Chilled Glass Research Articles

Effect of Smoking on Human Buccal Mucosal Cells: A Micronucleus Assay

Cigarette smoking causes several health problems and deadly diseases like cancer. Cigarette contains many deadly carcinogenic agents which activate in different tissues causing DNA damage. This damage is proportional directly to the frequency and duration of the exposure. Micronuclei are the formed basically due to genetic damage to living cells. Micronucleus (MN) is nuclear body that is formed by chromosome breakage or segregation of chromosome during cell division and can be easily detected in exfoliated buccal cells. This study was carried out to estimation of DNA damage in exfoliated buccal cells in smokers. Therefore the present study was carried out to evaluate the genetic damage using MN assay of exfoliated buccal cells in nonsmokers (comparison group), smokers with respect to duration and frequency of smoking. Two groups of people were taken, twenty five each for smokers, and nonsmokers. Informed consent was taken and relevant information was obtained using a questionnaire. Subjects were instructed to rinse their mouth thoroughly with normal saline two times, before taking the buccal mucosa cells. The buccal mucosa cells that were exfoliated by scrapping the buccal mucosa using new spatula and they were spread over the chilled glass slide after the cells were centrifuged. The slides were stained using Giemsa stain and were mounted for microscopic evaluation. Three hundred cells were counted. Results were noted. Statistical analysis was done using independent sample t-test. The mean and standard deviation in Controls and Smokers were 0�16±0�47 and 1�20±1�22 respectively. Independent sample t-test value showed no difference that was significant in the means between the two groups (p = 0�35). There was no statistical significance observed among Controls and Smokers. This may be due to the small sample size.

Drawing a Breath

Drawing a Breath Kaitlyn Teer (bio) I It starts and ends with a breath. The shock of air on a newborn’s cheek, the cold kiss of it. This is what beckons a first breath. It isn’t born of need, not a hunger for air nor scarcity that compels us to fill our lungs for the first time. Rather, drawing a breath is our natural response to the abundance of air. Air stirs the fine hairs on infant bodies, sways lanugo like seaweed underwater. A gale-force rush of stimuli triggers neurons, which spark in the brain. Unfamiliar waves of sound and light roll in: vibrations resonate within the ear canal, and brightness flashes upon the retina in fuzzy shapes. So it happens upon arrival, within the first ten seconds of extrauterine experience. It seems our first breath holds wonder. More an involuntary gasp of surprise than of survival. Upon encountering the world, the most fitting response is to open our mouths and take it in. We expand as it fills us. This initial inhalation is a moment that is unrepeatable: for the first time lungs trade fluid for air, an exchange of gases, and then, the umbilical cord with its oxygen-rich blood is cut. My friend, who is a midwife, stands in her kitchen making pizza and talking about the first breaths she has witnessed. Her hands hold the fixed ends of a rolling pin as she leans over the counter, working the dough. She tells me about the small, slippery bodies she catches. She holds these curled newborns up to their mothers’ chests and waits for the shallow expansion and contraction of tentative lungs under her palms. She pauses and smiles as her toddler interrupts our conversation. He chases a toy across the tiled kitchen floor while exclaiming “woah.” He says this many times, always with the same ecstatic appreciation. He is amazed that a toy man can sit in a toy car, amazed at the pizza pan in the oven, amazed at his own reflection as he presses his hands, lips, and nose against the chilled glass of the back door, leaving smudgy fingerprints in fog. [End Page 124] You can measure a lifetime in breaths. An eighty-year-old: 672,768,000 breaths. A fifty-five-year-old: 420,480,000 breaths. A twenty-five-year-old: 210,240,000 breaths. In and out, impossible to count each one, and yet not one of them is like the first breath. “I once took a nine-hour seminar on infant resuscitation,” my friend says. “Not just the mechanics of it, but to explore the meaning of it, the significance.” She tells me what happens when a baby is born but doesn’t breathe, tells me of the stillness in the room except for the effort to bring into being the one small body whose chest has yet to rise and fall. She tries to tell me what it’s like to breathe in and out, offering air to airless lungs. This giving of breath, to breathe for one who has never known air, is unlike any other resuscitation, more a suscitation, a rousing to life. II In the old-growth forest, the nearness of aged beings silences me. It is the quietude of Douglas firs, hush of hundreds of years of respiration. I sense in the air the scent of reciprocity, stomatal openings receiving carbon dioxide and delivering oxygen in return. My parents have traveled across the country to visit us and they walk with my husband and me under a canopy of firs as we hike toward Fragrance Lake. Mottled light covers the chipped path before us, carved into a carpet of vigorous sword ferns. All around us, moss makes its patient creep across bark and stone. The first mile is a steep incline. My father pauses occasionally to unclip his cell phone from his belt and take a photo, to study the globed web of an orb-weaver spider or the exposed root system of a fallen tree. He lags behind us, taking his time, smiling up at us during switchbacks. When he stops again to retie the laces of his sneakers, I...

Development and Property Evaluation of Chilled MMC Prepared with LM25 as Matrix and SiO<sub>2</sub> (Glass) Particulates as Dispersoids

Main objective of the present work is to investigate the effect of dispersiod content and the effect of chill on the mechanical properties of chilled MMC with LM25 as matrix and SiO2 as dispersoid. Investigation is carried out to evaluate Ultimate Tensile Strength (UTS), Fracture toughness, Hardness, and microstructure of chilled aluminum matrix and Glass particulate composite. The glass (SiO2) particles ranging from 30-to100µm were chosen as dispersiod and added, ranging from 3to 12wt% in steps of 3%. The composite was prepared by stir-casting technique and poured into the sand molds incorporated with non-metallic and metallic chills. Test result showed that this MMC was greatly influenced by the dispersiod and chills. Fracture toughness & UTS of the composite are found to depend on the wt% of the dispersiod and chilling medium. It is observed that chill has influenced hardness of the composite. Volumetric heat capacity (VHC) of the chill is found to increase the amount of heat absorbed. Microstructure analysis has reveled uniform distribution of the dispersiod, which results in improved properties of the particulate reinforced metal matrix composite.

A compact semi–continuous atmospheric aerosol sampler for elemental analysis: a preliminary result

A compact semi–continuous atmospheric aerosol sampler has been developed for subsequent elemental analysis by inductively coupled plasma mass spectrometry (ICP–MS). The sampler is basically a downsized and simplified version of the University of Maryland Semi–continuous Element in Aerosol Sampler–II (SEAS–II) and is hereafter referred to as the Korean version of SEAS (KSEAS). It has four major components: a steam generator, a particle growth chamber, a particle impactor, and a fractional XY collector. The air flow rate of this sampler is 16.7 L min−1, roughly one fifth of the flow rate of SEAS–II. Due to the lower volume sampling rate, a virtual impactor is not needed, which makes it simple to fabricate and use. The absence of a virtual impactor also improves sample collection efficiency. Ambient air is withdrawn to a particle growth chamber where it mixes with a hot steam flow. As the resulting supersaturated air flows downward, its temperature decreases due to heat loss to the lower part of the water–chilled glass wall. Finally, air–flow is directed to a particle impactor where moisturized aerosol–laden droplets accumulate at the bottom as an aqueous solution, which is withdrawn periodically to a fraction collector. To evaluate the validity and field applicability of our sampler, we used it and SEAS–II to collect PM2.5 and PM10 in Seoul, Korea over the period of a month. Collected samples were analyzed for several key elements using ICP–MS. Elemental analysis results showed good to excellent correlation coefficients, ranging from 0.3~0.9 (n=586), between the two samplers, confirming the validity of KSEAS. Due to the lower volume sampling rate, the detection limits of KSEAS is higher than those of SEAS–II (2~5 times higher). However, lower sampling volume needs lower power for operation and provides a better field applicability.

Drivers of explosivity and elevated hazard in basaltic fissure eruptions: The 1913 eruption of Ambrym Volcano, Vanuatu (SW-Pacific)

Fissure-eruptions along linear structures can extend for several tens of kilometres with distinct separate manifestations of volcanism along their length. They typically involve low-viscosity mafic magmas forming long lava flows and cinder cones. Eruptions in 1894 and 1913 on Ambrym volcano, Vanuatu, showed how these mildly explosive eruptions can rapidly transform into violent explosive events, producing significant hazard and widespread volcanic ash clouds. During the 1913 episode, a fissure began in the central caldera and basaltic magmas broke out in a series of locations down the island's western flank. In all sites over 100 m in elevation, fissure outbreaks produced vigorous lava fountains and highly fluid lava flows that travelled rapidly to the shoreline. When the outbreaks propagated along the island's axis into coastal plain areas, a climactic series of explosive eruptions occurred, producing a 1.2 km long by 600 m wide maar and tephra ring. A further small tuff ring was formed later, creating a temporary island 400 m offshore. The onshore tephra ring destroyed a hospital and associated buildings. Its last evacuating occupants were close witnesses to the eruption processes. Deposits exposed in the lower portion of the tephra ring show that this part of the eruption began with a mild phreatomagmatic explosive eruption from a narrow vent, followed by a magmatic scoria-producing phase. Subsequently a complex sequence of highly explosive phreatomagmatic eruptions occurred, producing pyroclastic surges, along with repeated distinctive breccia-horizons, rich in coral and lava country rock. These features tally with eye-witness accounts to indicate that the main eruption phase was produced by a periodically shifting locus of phreatomagmatic fragmentation and eruption along a single E-W fissure. The glassy and vesicle-poor pyroclasts produced during this eruption phase were dominantly fragmented in a brittle manner by magma water interaction. Low volatile content of the magma upon fragmentation is confirmed by FTIR analysis showing < 0.5% H 2O in chilled glass. These findings highlight that a degassed, mafic, fissure-fed eruption can under certain circumstances pose a major volcanic hazard if dykes intersect substrates with abundant available water.

Rga4 Modulates the Activity of the Fission Yeast Cell Integrity MAPK Pathway by Acting as a Rho2 GTPase-activating Protein

Rho GTPase-activating proteins (GAPs) are responsible for the inactivation of Rho GTPases, which are involved in the regulation of critical biological responses in eukaryotic cells, ranging from cell cycle control to cellular morphogenesis. The genome of fission yeast Schizosaccharomyces pombe contains six genes coding for putative Rho GTPases, whereas nine genes code for predicted Rho GAPs (Rga1 to Rga9). One of them, Rga4, has been recently described as a Cdc42 GAP, involved in the control of cell diameter and symmetry in fission yeast. In this work we show that Rga4 is also a Rho2 GAP that negatively modulates the activity of the cell integrity pathway and its main effector, MAPK Pmk1. The DYRK-type protein kinase Pom1, which regulates both the localization and phosphorylation state of Rga4, is also a negative regulator of the Pmk1 pathway, but this control is not dependent upon the Rga4 role as a Rho2-GAP. Hence, two subsets of Rga4 negatively regulate Cdc42 and Rho2 functions in a specific and unrelated way. Finally, we show that Rga7, another Rho2 GAP, down-regulates the Pmk1 pathway in addition to Rga4. These results reinforce the notion of the existence of complex mechanisms determining the selectivity of Rho GAPs toward Rho GTPases and their functions.

Pillow lavas of the Sierra Leone test site, Mid-Atlantic Ridge, 5°–7°N: Sr-Nd isotope systematics, geochemistry, and petrology

Based on detailed petrological, geochemical, and isotope-geochemical study, fragments of fresh pillow lavas with chilled glass margins dredged at the Sierra-Leone test site in the axial MAR rift zone between 5° and 7°N correspond to MORB tholeiites, which are not primitive mantle melts but were differentiated in intermediate magmatic (intrusive) chambers. Small-scale geochemical and Sr-Nd isotope heterogeneities were established for the first time in the basalts and their glasses. It was shown that some samples show significant nonsystematic differences in the 87Sr/86Sr ratio between the basalts and their chilled glasses and less significant difference in ɛNd; higher Sr ratios can be observed both in the glasses and basalts of the same lava fragments. No significant correlation is observed between the isotope characteristics of the samples and their geochemistry; it was also shown that seawater did not affect the Sr and Nd isotope composition of the chilled glasses of the studied pillow lavas. It is suggested that such differences in isotope ratios are related to a small-scale heterogeneity of the melts owing to incomplete homogenization during their rapid ascent to the surface. The heterogeneity of the basaltic melts is explained by their partial contamination by the older plutonic rocks (especially gabbroids) of the lower oceanic crust, through which they ascended to the ocean floor surface. The wider scatter of the Sr isotopic ratios relative to Nd is related to the presence of xenocrysts of calcic plagioclase; correspondingly, the absence of a Nd mineral carrier in the rocks results in less distinct Nd isotope variations. It was shown that all of the studied basalts define a single trend along the mantle correlation array in the Sr-Nd isotope diagram. The causes of this phenomenon remain unclear.

Inhibition of Nuclear Import of LIMK2 in Endothelial Cells by Protein Kinase C-dependent Phosphorylation at Ser-283

LIM kinases (LIMKs) are mainly in the cytoplasm and regulate actin dynamics through cofilin phosphorylation. Recently, it has been reported that nuclear localization of LIMKs can mediate suppression of cyclin D1 expression. Using immunofluorescence monitoring of enhanced green fluorescent protein-tagged LIMK2 in combination with photobleaching techniques and leptomycin B treatment, we demonstrate that LIMK2 shuttles between the cytoplasm and the nucleus in endothelial cells. Sequence analysis predicted two PKC phosphorylation sites in LIMK2 but not in LIMK1. One site at Ser-283 is present between the PDZ and the kinase domain, and the other site at Thr-494 is within the kinase domain. Activation of PKC by phorbol ester treatment of endothelial cells stimulated LIMK2 phosphorylation at Ser-283 and inhibited nuclear import of LIMK2 and the PDZ kinase construct of LIMK2 (amino acids 142-638) but not of LIMK1. The PKC-delta isoform phosphorylated LIMK2 at Ser-283 in vitro. Mutational analysis indicated that LIMK2 phosphorylation at Ser-283 but not Thr-494 was functional. Serum stimulation of endothelial cells also inhibited nuclear import of PDZK-LIMK2 by protein kinase C-dependent phosphorylation of Ser-283. Our study shows that phorbol ester and serum stimulation of endothelial cells inhibit nuclear import of LIMK2 but not LIMK1. This effect was dependent on PKC-delta-mediated phosphorylation of Ser-283. Since phorbol ester enhanced cyclin D1 expression and subsequent G1-to-S-phase transition of endothelial cells, we suggest that the PKC-mediated exclusion of LIMK2 from the nucleus might be a mechanism to relieve suppression of cyclin D1 expression by LIMK2.

Interaction of sea water and lava during submarine eruptions at mid-ocean ridges.

Lava erupts into cold sea water on the ocean floor at mid-ocean ridges (at depths of 2,500 m and greater), and the resulting flows make up the upper part of the global oceanic crust. Interactions between heated sea water and molten basaltic lava could exert significant control on the dynamics of lava flows and on their chemistry. But it has been thought that heating sea water at pressures of several hundred bars cannot produce significant amounts of vapour and that a thick crust of chilled glass on the exterior of lava flows minimizes the interaction of lava with sea water. Here we present evidence to the contrary, and show that bubbles of vaporized sea water often rise through the base of lava flows and collect beneath the chilled upper crust. These bubbles of steam at magmatic temperatures may interact both chemically and physically with flowing lava, which could influence our understanding of deep-sea volcanic processes and oceanic crustal construction more generally. We infer that vapour formation plays an important role in creating the collapse features that characterize much of the upper oceanic crust and may accordingly contribute to the measured low seismic velocities in this layer.

MAR volcanism in the Sierra Leone Fracture Zone region, Central Atlantic

We have studied major and trace element (including REE) geochemistries of basalts and chilled basaltic glasses from the MAR axial zone in the vicinity of the Sierra Leone FZ (5 -7 10 0 N). The links of basalts of various compositions with particular ocean- floor geological structural features have been analyzed as well. Three basaltic varieties have been discriminated. Almost ubiquitous are high-Mg basalts that are derivatives of N-MORB tholeiitic melts and that are produced in the axial zone of spreading. Variety 2 is alkaline basalts widespread on the southwest flank of the MAR crestal zone in the Sierra Leone region, likely generated through deep mantle melting under plume impact. Variety 3 is basalts derivative from T- and P-MORB-like tholeiitic melts and originating through addition of a deeper mantle material to depleted upper mantle melts. Magma generation parameters, as calculated from chilled glass compositions, are dierent for depleted tholeiites (44-55 km, 1320-1370 C) and enriched tholeiites (45-78 km, 1330-1450 C). Mantle plume impact is shown to aect not only tholeiitic basalt compositions but also magma generation conditions in the axial spreading zone, resulting in higher Ti and Na concentrations in the melts parental to the rift-related basalts occurring near the plume. T- and P-MORBs are also developed near the areas where mantle plumes are localized. The high-Mg basalts are shown to come in several types with distinctive Ti and Na contents. Nearly every single MAR segment (bounded by sinistral strike slips and the Bogdanov FZ) is featured by its own basalt type suggesting that it has formed above an asthenospheric diapir with its unique magma generation conditions. These conditions are time variable. The likely causes of the temporal and spatial instability of mantle upwelling beneath this portion of the MAR are singular tectonic processes and plume activity. In the sulfide-bearing rift morphostructures (the so-called Ore area and the Markov Basin), basalts make up highly evolved suites generated through olivine and plagioclase fractionation, which is suggestive of relatively long-lived magma chambers beneath the sulfide-bearing rift morphostructures. The functioning of these chambers is a combined eect of a singular geodynamic regime and plume activity. In these chambers, melts undergo deep dierentiation leading to progressively increasing concentration of the sulfide phase, eventually to be supplied to the hydrothermal plumbing system.

Short-term leptin infusion does not affect circulating levels of LH, testosterone or cortisol in food-restricted pubertal male rhesus macaques.

Although the adipocyte protein leptin has been implicated in the control of reproductive function in rodents, its role in primate reproductive physiology is poorly understood. Because primates in puberty show nighttime LH secretion and there is considerable evidence that the fertile state requires adequate nutrition, we reasoned that animals on the verge of reproductive competence would respond to leptin infusions by secreting LH. Food restriction reduces circulating leptin levels and slows or stops the GnRH pulse generator. Therefore, we examined the endocrine effects of leptin infusions in food-restricted male pubertal primates during the night when they normally secrete LH. In addition, we investigated the effect of leptin on in vitro testosterone production by Leydig cells. Four pubertal male rhesus macaques (Macaca mulatta), 4-5.5 kg in weight (2.5-4-year-old) were examined in this study. Leydig cells from adult male rats were to investigate in vitro effects of leptin. To document that animals had entered puberty, blood samples were collected from each of the four animals at 15-minute intervals for 15 h both during the day and at night. Since at this age animals secrete LH mainly at night, blood samples were collected at 15-minute intervals from each of the four animals on two separate occasions for 15 h between 1500 and 0600h. During the experiment, animals were feeding from 0800 to 0830h, cages were completely cleaned of food at 0900h and the afternoon meal was not given to individual animals on the day they were studied. One of the studies served as the control (food restricted group) and during the other, 2 mg (n = 4) or 0.3 mg (n = 3) of recombinant human leptin was administered intravenously during 2000-0100h (food restricted plus leptin group). Blood samples (1 ml) were collected through the indwelling catheter and immediately transferred from the plastic syringe into chilled glass tubes containing 10 microl 14% EDTA. The samples were centrifuged at 5-h intervals and the plasma withdrawn and stored frozen at - 20 degrees C in polypropylene vials until assays were performed. Bioactive LH was determined and testosterone, cortisol and leptin were measured by radioimmunoassay. During daytime experiments in these animals, LH pulses were sometimes observed late in the day and generally continued for 12-15 h. Food-restricted pubertal males showed delayed or absent LH pulses. Short-term leptin administration to food-restricted male rhesus macaques had no effect on LH, testosterone, or cortisol levels either during or after the infusion. Leptin also had no direct effect on basal or LH-stimulated testosterone production in Leydig cells. Our data support the notion that leptin is not the missing signal for the acute suppression of reproductive hormones secretion in food-restricted primates.

Optically Transparent Polymethyl Methacrylate Composites made with Glass Fibers of Varying Refractive Index

The dependence of the optical and mechanical properties of optically transparent polymethyl methacrylate (PMMA) composites on the annealing temperature of BK10 glass fibers was investigated. Annealing was used to modify the refractive index (R.I.) of the glass fiber so that it would more closely match that of PMMA. Annealing increased the refractive index of the fibers and narrowed the distribution of refractive index of the fibers, but lowered their mechanical strength so the mechanical properties of composites reinforced with annealed fibers were not as good as for composites containing as-pulled (chilled) glass fibers. The refractive index of as-pulled 17.1 μm diameter fibers (R.I. = 1.4907) increased to 1.4918 and 1.4948 after annealing at 350 °C to 500 °C for 1 h or 0.5 h, respectively. The refractive index of glass fibers annealed at 400 °C/1 h best matched that of PMMA at 589.3 nm and 25 °C, so the composite reinforced with those fibers had the highest optical transmission. Because annealed glass fibers had a more uniform refractive index than unannealed fibers, the composites made with annealed fibers had a higher optical transmission. The mechanical strength of annealed fiber/PMMA composites decreased as the fiber annealing temperature increased. A composite containing fibers annealed at 450 °C/1 h had a tensile strength 26% lower than that of a composite made with as-pulled fibers, but 73% higher than that for unreinforced PMMA. This decrease was avoided by treating annealed fibers with HF. Composites made with annealed and HF (10 vol. %)-treated (for 30 s) glass fibers had a tensile strength (∼200 MPa) equivalent to that of the composites made with as-pulled fibers. However, as the treatment time in HF increased, the tensile strength of the composites decreased because of a significant reduction in diameter of the glass fiber which reduced the volume percent fiber in the composite.

The effects of temperature on the setting of glass ionomer (polyalkenoate) cements

Glass ionomer (polyalkenoate) cements have proved to be superior to zinc phosphate cements as orthodontic luting agents. Setting behaviours at different temperatures were recorded by an oscillating rheometer under controlled conditions. The working time of these cements can be increased by mixing on a chilled glass slab with setting time at mouth temperatures remaining rapid. Where more than one orthodontic band is cemented per mix, the authors recommend refrigeration of the glass slab for at least one hour prior to mixing the cement.

Excess 3He in oceanic basalts: Evidence for terrestrial primordial helium

Helium trapped in the chilled glass rims of Pacific Ocean basalts is highly enriched in 3He; the 3He/ 4He and 3He/Ne ratios are respectively 10 and 1000 times the atmospheric ratios. We interpret these large enrichments as further evidence that primordial 3He is still present in the interior of the earth. The 3He/ 4He ratio in basalt glass is the same as the isotope ratio of the “excess helium” in Pacific Ocean deep water, supporting the theory that the atmospheric escape rate of 3He is balanced by a flux of primordial 3He from the mantle.

Quantitative Measurements of Endogenous Levels of Acetylcholine and Choline in Tetrathyridia of Mesocestoides corti (Cestoda) by Means of Combined Gas Chromatograph-Mass Spectrometry

Endogenous levels of choline and acetylcholine in tetrathyridia of Mesocestoides corti were determined under different environmental conditions. The highest values of choline and ACh were obtained when tetrathyridia were washed in media NCTC 135 and Eagle's Basal Medium. The lowest values were obtained when organisms were washed in 0.85% NaCl, or BME without choline chloride. Incubation of organisms in different concentrations of physostigmine showed an increase in the ACh level. The levels of choline and ACh decreased with decreasing drug concentration. DFP also showed a similar effect on choline and ACh. Oxotremorine increased choline and ACh levels but the increase was considerably lower than in physostigmine or DFP-treated organisms. While the histochemical association of acetylcholinesterase (AChE) with the nervous system has been the primary means of claiming the presence of acetylcholine (ACh) in helminthic tissue, a few workers have demonstrated ACh by biochemical isolation. Bueding (1952) showed that extracts of Schistosoma mansoni contain high levels of AChE and choline acetylase activities. Barker et al. (1966) reported the level of ACh in S. mansoni to be 5.3 jug/g wet weight. Chance and Mansour (1953) demonstrated AChE and choline acetylase activities in the liver fluke, Fasciola hepatica. Furthermore, they reported that this parasite contains an ACh-like substance. The presence of ACh was demonstrated in Ascaris by Mellanby (1955) who showed that the head region contains a much higher level than the body. Several biochemical methods are routinely used for determining ACh-like activity in extremely small amounts, but their reliability has been questioned (Hosein and Orzek, 1966; Stockley, 1969) in view of the fact that their response is not specific to one compound alone. Definitive identification of ACh and choline Received for publication 2 November 1973. * This investigation was aided in part by research grant USPHS AI-11107-01 from the NIH, Bethesda, Maryland. t Recipient of USPHS-NIAID Training Grant No. TOI-A1-00249. + Grand Island Biological Company, 519 Aldo Avenue, Santa Clara, California 95050. was made in tetrathyridia of Mesocestoides corti by means of a combined gas chromatograph-mass spectrometry (GC-MS) system. The functional aspects of ACh in this parasite will be reported elsewhere. MATERIALS AND METHODS Tetrathyridia of Mesocestoides, originally isolated from lizards (Specht and Voge, 1965), were maintained in Swiss albino mice. The animals were killed by cervical dislocation and tetrathyridia were transferred from the body cavity into petri dishes containing GIBCOt NCTC 135, "Eagle's Basal Medium" (BME) with or without choline chloride, or physiological saline solution (0.85% NaCl). Worms were preincubated in BME without choline chloride for a maximum of 1/2 hr before exposure to drug. The number of worms never exceeded 20 per ml of medium. The maximum period of incubation was 1 hr. For each drug concentration, the motility of worms was observed under the dissecting microscope at 15, 30, 45, and 60 min. The effect on choline and ACh levels by 3 different concentrations of physostigmine salicylate and 2 concentrations of oxotremorine and diisopropylfluorophosphate (DFP) was tested. The effect of each concentration was tested 3 times and organisms for each concentration were obtained from a different mouse. After incubation at 37 C, parasites were washed and dried by use of aspiration of fluids or by means of a Millipore filter. Organisms were then removed with a frozen spatula and immediately immersed in liquid nitrogen. The entire process of washing and drying lasted 6 to 8 min. Organisms were pulverized by the method of Campbell et al. (1970). The finely powdered tissue, 0.066 to 1.11 g, was transferred to a tared, chilled glass homogenizer to prevent thawing, and weighed. With few exceptions, the

The Role of Tin in Copper Ruby Glass—Viscosity Measurements

A new mechanism for striking of colour in copper ruby glass was recently suggested: 2 Cu-O-Si≡ (chilled glass) striking → Cu2O (red colourant) −+≡Si-O-Si≡. It does not need tin, considered essential as per the earlier mechanism. The actual role of tin has therefore been investigated. A copper ruby glass melted without tin became amber indicating the presence of Cuo. For confirmation, its low temperature viscosity has been studied. Viscosity of chilled glass remains unchanged on annealing. This indicates presence of Cuo in chilled glass rather than of Cu+ which, on annealing, would have increased the viscosity several fold due to formation of bigger structural linkages. Hence in absence of tin the reduction of Cu+ to Cuo is almost instantaneous in the melt and the latter makes the glass amber. Cu+ being absent, formation of Cu2O (red colourant) is not possible on striking. But when tin is used, availability of Cu+ is prolonged. It is likely that tin acts as a protector for Cu+ in molten glass. Probably rea...

The effect of fixation on the autoradiographic grain count

AMONGST the most popular fixatives of animal tissues for light microscope autoradiography are formalin, ethyl alcohol, ethyl alcohol mixtures (e.g. those of Belanger and Carnoy), and glacial acetic acid mixtures (for example, Bouin’s and its modifications). It is reasonable to expect that the fixative might be important in subsequent autoradiographic studies, and KOPRIWA and LEBLOND (1962) have obtained significantly different counts with different fixatives of pieces of liver from a 3H-cytidine injected mouse. This report outlines a satisfactory technique for light microscopeautoradiography of developing dental tissues and compares the effect of several fixatives on the autoradiographic grain counts from ameloblasts labelled with tritiated proline. Fourteen-day old albino rats (Wistar strain) were injected with 8 PC per g of body weight of jH-proline (Radiochemical Centre, Amersham, England; spec. activ 253 mc/mM). The animals were killed by decapitation at intervals of 20 min, 60 min, and 90 min, after the injection. Each head was quicklydissectedinto fourjawquadrants, which were each placed into one of four fixatives : buffered neutral formalin, Hollande modification of Bouin’s fluid (JONES, 1966), 3 per cent glutaraldehyde in sodium cacodylate buffer, and glutaraldehyde with osmium tetroxide post-Gxation. The first three were processed for light microscopy and the fourth was processed and kept for subsequent electron microscopy. The tissues for light microscopy were fixed for 3 days at room temperature, decalcified in 10 per cent EDTA, washed in several changes of distilled water and embedded in paraffin. Sections 6 p thick were placed on gelatinized slides and prestained with Mayers haematoxylin and eosin. The liquid emulsion technique used for autoradiography came mainly from the methods reported by KOPRIWA and LEBLOND (1962), KOPRIWA (1966) and ROGERS (1967). Ilford K2 emulsion was diluted with an equal volume of 0 5 per cent glycerol in distilled water and all slides were coated in a uniform manner by means of a dipping machine (KOPRIWA, 1966); the time of withdrawalof each slide from the emulsion was 42 sec. The back of each slide was wiped clean and the slide was then placed to cool, face downwards, upon a chilled glass slab. The slides were stacked in Clay-Adams light-tight boxes which were flushed out with COz before sealing, and the sealed boxes of slides were stored at 4°C in a lead-lined container. Each box contained sections from all three fixatives. All slides were developed after 8 days in the following developer: 2 ~2 g sodium sulphite (anhydrous) plus 1 *O g amidol, made up to 620 ml with distilled water and

Studies On Phosphatase Activity In Some Parasitic Helminths

In order to obtain some informations on the nature and relative activity of the phosphatases present in various helminths, biochemical studies have been made in thirteen kinds of worm parasites including the adults and larvae (Fasciola hepatica, Eurytrema pancreaticum, Paramphistomum sp., Taenia solium, Taenia pisiformis, Dipylidium caninum, Diphyllobothrium mansoni, Cysticercus cellulosae, Cysticercus fasciolaris and Sparganum). A comparison based on the analysis of pH-activity curves was made among these helminths. The worm materials were mostly obtained alive from an abattoir and removed from the organs or tissues of the animal hosts naturally infected. Sparganum and Cysticercus cellulosae, however, are collected from the subcutaneous tissue of the patients by surgical removal. The worms thoroughly washed were weighed and transferred with 0.1 M Tris buffer to a chilled glass grinder (Capacity; 15 ml) and homogenized in the cold. The homogenate was centrifuged at 5000 RPM for 30 minutes. The supernatant was pipetted off for determination of the phosphatase activity. Incubation mixtures consisted of 1 ml substrate, 1 ml buffer and 0.5ml extract. The buffers used were Tris (Hydroxymethyl) aminomethane and citric acid monohydrate and the substrate was paranitrophenyl phosphate (1 gm/25 ml). These mixtures were incubated at the temperature of 37 degrees C for 30 minutes in water bath. The absorbance or transferance of mixture was determined colorimetrically by "Spectronic 20 "spectrophotometer at 410 nm against a distilled water blank. The amount of phenol liberated was then calculated from a standard curve using phenol solutions. Controls consisted of unincubated mixtures. The results were deducted from this experiment. The phosphatase activity occurred over all parasitic helminths used in this experiment. In trematodes, pH-activity curves have demonstrated two peaks of phosphatase activity in Fasciola hepatica and Paramphistomum species. However the acid phosphatase activity was predominantly found and the alkaline phosphatase activity was found distinctly to be low in all three species. In Eurytrema pancreaticum, the pH-activity curves displayed two peaks in acid phosphatase activity, one at pH 5.0 and the other pH 9.0. In cestodes, both alkaline and acid phosphatase activity displayed the pH optima 5.0 and 9.0 to 10.0 in the adult tapeworms. However, major activity in the adults is due to the alkaline phosphtases. In contrast to the adults, Cysticercus and sparganum showed the higher activity in acid phosphatases which predominates in the larvae. In all cases of nematodes, the pH optimum for acid phosphatase was 4.0 to 6.0. A preponderance of acid phosphatase activity was shown in the extract of intestine of Ascaris lumbricoides. The aspect that phosphatases are correlated with phosphorylated passage of substances through the cuticle of helminths and may also be involved in carbohydrate metabolism is discussed.

Studies On Lactic Dehydrogenase Activity In Parasitic Helminths

A series of experiments was performed to determine the lactic dehydrogenase activity of various parasitic helminths. The enzyme activity was determined by the modified method of Wroblewshi and LaDue (1955) using tissue homogenate of 16 kinds of worm parasites. The worms were mostly collected alive from local abattoir and removed from the organ or tissues of the naturally infected animal host and some materials were also obtained from the human host. They were thoroughly washed and homogenized in chilled glass tissue grinder, and then centrifuged. The supernatants were designated as enzyme preparations, and their enzyme activity was measured by spectrophotometry at the wave length of 340 millimicron. In order to know the effects of temperature and substrate concentration on the enzyme activity, the extinction of reduced Coenzyme I(NADH) was measured at the various conditions of incubation temperature and substrate concentration. The results of this experiments were as follows: 1. The lactic dehydrogenase activity occurred over all kinds of parasites used in this study. 2. Most worms of nematodes and trematodes displayed their maximum activity in the range of pH 2.7~3.5, and cestodes revealed their maximum activity in the ranges of both pH 2.7~3.5 and pH 7.4. 3. In nematodes and trematodes, the lactic dehydrogenase activity increased slowly as incubation temperature increases except in the case of Eurytrema pancreaticum, while the activity in cestodes decreased inversely. 4. The lactic dehydrogenase activity increased in proportion to the increase of substrate concentration in most of worm parasites.

PROXIMO-DISTAL INCREASE OF ENZYMIC ACTIVITY IN THE DORSAL SPINAL TRACTS.

IT IS known that enzyme distribution is not the same among various fibre tracts, but except for LUBLINSKA’S (1 962) report of a proximo-distal decrease of cholinesterase along peripheral nerves there is little information about differences of enzyme activity along the course of a given fibre tract. This paper presents biochemical and histochemical data of the distribution of lactate dehydrogenase (LDH) along the tractus gracilis (Goll’s tract) and the tractus cuneatus (Burdach’s tract). The enzymes cytochrome oxidase (CYO), succinate dehydrogenase (SDH), malate dehydrogenase (MDH), glutamate dehydrogenase (GDH), and glucose 6-phosphate dehydrogenase (G-6-PDH) were also studied histochemically. The data show a gradual proximodistal increase of most of these enzymes in the axons of both fibre tracts; however, the increase is much more pronounced in the tractus gracilis than in the tractus cuneatus. The possible significance of this phenomenon is discussed. Additional studies evidenced an inverse distribution of LDH in glial cells and axons along the course of the tractus gracilis: in the caudal part of the tractus gracilis, the LDH activity was strong in many glial cells and weak in the axons; in the cranial-most part of the tract, there was no LDH activity in glial cells but it was very intense in the axons. MATERIAL AND METHODS Assay methods. Biochemical determinations of the LDH activity at different levels of the tractus gracilis and tractus cuneatus were made in ten cats; two cats were used for preliminary establishment of a standard procedure for sampling. The results of studies on eight cats are included in the biochemical data. The cats were sacrificed with sodium pentobarbitone and the medulla oblongata and 6 cm of the cervical spinal cord were removed. The tissue was transferred to ice-cold saline and used within 10min. Transverse dorso-ventral incisions were made into the cord to divide the dorsal tracts into segments exactly 5 mm in length. By comparing the features of the cross section of the cord with the dorsal fissure, sulci and roots at its dorsal surface, the positions of the tractus gracilis and cuneatus were readily determined, and wedge-shaped samples were cut from each tract from the dorsal surface of the cord. In the beginning, after the assay sample was removed the remainder of the specimen was fixed and embedded in paraffin, and the stained sections were studied to determine if assay samples were free of contamination by adjacent tissue. After a little practice, uncontaminated samples of both tracts were obtained without difficulty. The wet weight of each sample, 23-7 mg, was determined immediately. These samples were transferred to chilled glass tissue-grinder tubes and homogenized with a motor driven pestle in ice-cold tris buffer, pH 7.4. Concentration of homogenates was 10 mg of tissue per ml of buffer. The incubation medium was slightly modified from that of ALLEN and SLATER (1961) for cytochemical determination of LDH: 1 ml sodium lactate, 0.5 M; 1 ml NAD, 0.01 M; 1 ml potassium cyanide,