Wet Weight Measurements Research Articles

Regional brain sodium, potassium, and water changes in the rat middle cerebral artery occlusion model of ischemia.

Middle cerebral artery occlusions (MCAo) in rats produce infarcts in the pyriform and frontoparietal cortex, extending into the lateral basal ganglia and parasagittal cortex. We estimated tissue H2O concentrations from wet and dry weight measurements and determined Na and K concentrations by atomic absorption spectroscopy in these areas of rat brains. Tissue samples were analyzed at 2, 4, and 24 hours after MCAo and sham MCAo, compared with normal values measured in unoperated rats. In the pyriform and frontoparietal areas, H2O concentrations increased to 34 and 7% greater than normal by 2 hours, and 89 and 94% by 24 hours after MCAo. Na concentrations rose in these areas to 73 and 37% greater than normal by 2 hours, and 281 and 330% by 24 hours. K concentrations did not change until 4 hours, but fell to 62 and 34% of normal in these areas by 24 hours. Such large ion shifts indicate severe tissue destruction. In the parasagittal cortex and basal ganglia areas, the ion and water changes were smaller and did not become significant until 24 hours after MCAo. Rates of Na entry into the infarct site were greatest at 0-2 hours, while the rates of K loss peaked later, between 2 and 4 hours. The difference in Na influx and K efflux resulted in net ion shifts that correlated highly with water entry, yielding a correlation coefficient of 0.992 (p less than 0.001) and a slope indicating that 1 ml of water entered the tissue with each 145 mumoles of ions. These findings strongly suggest that net ion shifts cause the early edema of regional brain ischemia.(ABSTRACT TRUNCATED AT 250 WORDS)

Age-bodyweight relationships to lung growth in the F344 rat as indexed by lung weight measurements.

Measurements of the total lung weights and the individual weights of the lung lobes of male F344 rats ranging in age from about 30 days to 140 days or more were made in order to determine how lung growth and the growths of the individual lung lobes relate to bodyweight over the course of maturation of this species. Additionally, in this study we also compared how each lung lobe grows relative to total lung growth, evaluated the ratios of lung dry weight to wet weight and obtained information on the weights of the trachea and extra-hilar main-stem bronchi as the F344 rat matures. The wet weights WLT of the trachea-lung preparations and the pooled lobe weights WPL as functions of rat bodyweight WB could be readily described by the following logarithmic expressions: WLT = 0.596 ln WB - 1.923, r = 0.95; WPL = 0.464 ln WB - 1.566, r = 0.96. Expressed as percentages of the pooled lobe weights, the individual lobes remained at constant values as the animals grew with the exception of the right caudal lobe which decreased between bodyweights of 72 and 96 g; absolute wet weight measurements of the individual lobes indicated that the right cranial, right middle and right intermediate lobes actually decreased in weight between bodyweights of 300 and 385 g. The dry weights of the lobes consistently represented approximately 22% of the wet weights regardless of animal age or bodyweight, and on average the airways represented about 20% of the weights of the intact airway-lung preparations over the course of animal maturation.

Effect of vasopressin on cold-induced brain edema in cats.

Centrally released arginine vasopressin (AVP) has been implicated in the regulation of intracranial pressure (ICP) and brain water, and is elevated in the cerebrospinal fluid (CSF) of some patients with pseudotumor cerebri or subarachnoid hemorrhage. The authors have examined the relationship of AVP levels in CSF to ICP and brain water content in three experimental groups of cats with and without cold-induced vasogenic edema. With the cats under general anesthesia, a cold lesion was made and cannulas were placed in the cisterna magna, lateral ventricle, and aorta. Subsequent central and systemic measurements were made while the animals were awake and free-roaming. In Experiment 1, endogenous AVP levels in CSF were measured every 12 hours over a 48-hour period by radioimmunoassay in cats with sham craniotomy, mild edema, or moderate edema; no significant difference was found between groups although a diurnal variation was seen (range 2 to 18 pg/ml). In Experiment 2, either carrier solution or AVP, in doses of 1.5 or 30 ng, was administered via a lateral ventricle every 2 hours over 24 hours in unlesioned cats. In Experiment 3, cats received 2 or 35 ng of carrier solution or AVP in a similar manner, but coupled with a cold lesion. The CSF AVP levels ranged from an average of 100 to 681 pg/ml and 1.4 to 11.9 ng/ml in the two dose groups in both experiments. Neither the low nor the high dose had an effect on brain water content in normal white matter (Experiment 2), but both doses increased brain water content in edematous white matter (p less than 0.05 in Experiment 3), as determined by wet and dry weight measurements of standardized pieces of white matter. The ICP was decreased by high-dose AVP in normal cats (p less than 0.01 at 24 hours), but in lesioned cats was unchanged by low-dose and increased by high-dose AVP (p less than 0.05 at 18 hours). The authors conclude that pharmacological doses of central AVP facilitate the production of vasogenic edema.

Responses to hypertonic solutions in guinea-pig atria: Changes in action potentials, force of contraction and calcium content

In left atria of guinea-pig hearts we studied the effects of Tyrode solution made hypertonic by the addition of mannitol (50 to 300 mosm/l). Electrical and mechanical performance were investigated at 0.1, 1 and 3 Hz. Up to 150 mosm/l a positive inotropic effect was observed, addition of 300 mosm/l caused a positive inotropic response followed by a long lasting negative inotropic effect. The positive inotropic effect depended on the frequency of stimulation: at the low frequency of 0.1 Hz the increase in force of contraction was so large, that in hypertonic solution the absolute value of developed tension at 0.1 Hz was actually larger than at 3 Hz. With 150 mosm/l mannitol the time to peak tension and the twitch duration were prolonged. These effects were also most prominent at 0.1 Hz. The action potential duration was shortened; the membrane hyperpolarized. The observed changes in action potential duration and the membrane hyperpolarization may reflect changes in cation concentration due to cellular dehydration. The propagation velocity of excitation was reduced in the absence of a detectable decrease in maximum rate of depolarization during the upstroke of the action potential. The cells did not behave as perfect osmometers because loss of tissue water as estimated from wet weight and dry weight measurements was smaller than expected for a 1.5-fold increase in tonicity. After having established complete exchange of tissue calcium with 45Ca, hypertonicity-induced changes in the cellular calcium content could be determined by changes in 45Ca content. At both frequencies of stimulation, the cellular calcium content increased to the same extent.(ABSTRACT TRUNCATED AT 250 WORDS)

電気刺激が健常骨格筋に及ぼす影響について

低周波電気刺激が健常な骨格筋に与える影響を調べる目的でラットの右側坐骨神経に毎日30分間,2週間にわたり周波数5Hzの電気刺激を加えて筋肉を収縮させ反対側下腿筋を対照として比較し以下の結果を得た.刺激側の筋肉はより赤味を帯び,筋重量は前脛骨筋,長趾伸筋,長母趾伸筋でそれぞれ約5.8%,10.2%,37.1%増加した.筋線維1個当たりの毛細血管数は前脛骨筋浅層,中間層で対照側ではそれぞれ1.32,1.35であるが,刺激側の筋肉では,1.68,1.88個に増加した.また刺激側のすべての筋線維にコハク酸脱水素酵素活性の上昇が認められた.

Effect of nerve extract on atrophy of denervated or immobilized muscles

Changes in denervated muscles are due to disuse caused by paralysis of the muscle and the loss of special neurotrophic substances. We determined the relative roles of these two factors in the production of atrophy in denervated rats' extensor digitorum longus (EDL) muscles. Muscles were denervated and/or immobilized (by fixation of the ankle) for 7 days. Some rats also received daily intramuscular injections of a saline extract of rats' sciatic nerves (2.0 mg protein/ml). Atrophy was assessed by measurement of wet weight, total protein, and cross-sectional areas of types IIA and IIB fibers (in sections stained for ATPase). Both denervation and immobilization produced significant decreases in weight, protein, and areas of fiber. The group of rats with denervated EDL muscles had significantly greater atrophy than the group with immobilized muscles. In another group, denervated EDL muscles had significantly greater atrophy than contralateral muscles which were immobilized. However, when denervated muscles were injected with nerve extract, they did not differ significantly from contralateral, noninjected, immobilized muscles. Comparisons of the group of rats in which one EDL was denervated with groups in which one muscle was immobilized or was denervated and injected with nerve extract, indicated that loss of trophic influence was responsible for about 40% of the decreases in wet weight, total protein, and cross-sectional area of type IIB fibers, and the remaining 60% was due to disuse. Loss of trophic influence was responsible for only about 5% of the atrophy of denervated type IIA fibers. Therefore, inactivity and loss of neurotrophic influence were responsible for the atrophy which occurred in denervated skeletal muscles, and these two factors influenced the two types of fiber differently. The component of denervation atrophy due to loss of trophic influence could be completely prevented by injection of substances extracted from peripheral nerves.

Differential Wetting in Some Lichens and Mosses: The Role of Morphology

The effect of morphology on water uptake was examined in eleven species of lichen and three species of moss, using a raining wind tunnel environment. Experiments were conducted using a variety of species to test for the influence of specific morphological features such as rhizines, isidia, papules, apothecia and lamellae, in the control of water uptake and storage. Experiments were also conducted to test for the effect of variation in overall morphology on water uptake in lichens and mosses. The results show that rhizines play a major role in the water relations of some species, but not in all. Apothecia in Umbilicaria muhlenbergii have no role in water uptake, nor do the surface papules of U. papulosa or the surface isidia of U. deusta, although the lamellae of U. muhlenbergii are exceedingly important. The upper and lower cortices of lichens were also shown to have a variable capacity for water absorption. The variation in the amount of time required to achieve saturation was the same in the lichens and mosses. This time varied from three minutes in P. juniperinum to over 300 minutes in Stereocaulon saxatile. Plants with a large surface area to weight ratio absorb water at an exceedingly rapid rate. Conversely, any poikilohydric plant showing a low surface area to weight ratio absorbs water very slowly. Variation in the morphology of lichens has been shown to control evaporative water loss (Larson 1979; Larson & Kershaw 1976) in a fashion similar to the way in which variation in leaf or stem morphology controls water loss in many higher plants. These studies are the only ones to date, however, that demonstrate this feature of the biology of lichens. In general, the earlier literature is composed of studies demonstrating, through a variety of techniques, that water loss and gain in lichens, and to a lesser extent in mosses, is a passive phenomenon, and that adaptations do not exist for controlling the plant's water balance (Blum 1973). The techniques used in the past to study water loss and gain tend to fall into two categories: first are immersion experiments in which lichens or mosses are either soaked thoroughly, then allowed to dry in still air (or conversely are plunged into water when dry, followed by measurement of the plant's wet weight as imbibition occurs); second are bell 007-2745/81/1-15$1.75/0 This content downloaded from 157.55.39.192 on Sun, 28 Aug 2016 04:41:35 UTC All use subject to http://about.jstor.org/terms 2 THE BRYOLOGIST [Volume 84

Measurement of cultured plant cell growth on filter paper discs

To measure growth of cell cultures with minimal or no disturbance, a thin layer of cells can be separated from the agar medium by a disc of filter paper. The disc and adhering cells are removed periodically, weighed, and replaced. With this filter paper growth assay it is possible to produce a complete growth curve from a single culture without sacrificing that culture. It provides immediate measurement of wet weight, and allows for transfer of cultures to different media without interruption of growth. During the initial stages of growth, cells are spread thinly over a large surface with relatively uniform exposure to the medium, thus combining some of the benefits of growth in suspension with the lower cost and simplicity of callus culture.

Effect of preservation on wet weight biomass of chironomid larvae

Preservation of four species of chironomid larvae in either 10% formalin or 70% ethanol caused changes in the preserved wet weight expressed as a percentage of the original live wet weight. The magnitude of the change varied with species, preservative, preservation time and the nature of the water used for preservative dilution. Failure to take these factors into account can lead to errors in wet weight measurements as great as 47%. The use of io% formalin prepared with filtered habitat water appears to be the most suitable preservative for chironomid larvae.

The histological effects of copper and zinc on chick embryo skeletal tissues in organ culture

1. The effects of copper and zinc on organ cultures of chick embryo cartilage and bone maintained in low-trace-metal, chemically defined media for up to 8 d were studied macroscopically, histologically and histochemically. Length and wet-weight measurement of explants were assessed statistically. 2. No effects were found with Cu concentrations of 0-5-1-5 mug/ml medium. Between concentrations of 5 and 40 mug Cu/ml medium, lengths and wet-weights of cartilage cultures decreased significantly (P less than 0-001) compared with controls. The decrease was directly proportional to increasing Cu concentration, and that of the length was greater with increasing period of culture (P less than 0-001). 3. With 5--20 mug Cu/ml medium cartilage and bone became yellow in colour, and chondrocytes were swollen, rounded and basophilic. They were detached from their lacunae and the quantity of matrix was reduced. Loss of alkaline phosphatase (EC 3.1.3.1) activity and disappearance of glycogen accompanied the degeneration. Osteogenesis ceased, cells failed to divide and mature, lost their enzymes and died. Cu did not accumulate in the bone matrix. 4. The direct toxic effects of Cu for cartilage and bone may underlie some of the skeletal changes in hepatolenticular degeneration (Wilson's disease). 5. As Zn concentrations were increased from 2-5 to 7-5 mug/ml medium, lengths and wet-weights of cartilaginous cultures were significantly increased (P less than 0-001). As Zn concentrations were further increased (from 10 to 40 mug/ml medium), lengths and wet-weights were significantly decreased (P less than 0-001). 6. Zn stimulated chondrocyte division and vacuolation of cytoplasm. With higher Zn concentrations toxic changes of granular basophilia, lacunar detachment and necrosis were seen. Differentiation and functioning of osteoblasts, osteoclasts and chondroclasts were stimulated by Zn. 7. Zn was found in bone matrix, osteoblasts, osteocytes and hypertrophied chondrocytes.

The histological effects of copper and zinc on chick embryo skeletal tissues in organ culture

1. The effects of copper and zinc on organ cultures of chick embryo cartilage and bone maintained in low-trace-metal, chemically defined media for up to 8 d were studied macro-scopically, histologically and histochemically. Length and wet-weight measurement of explants were assessed statistically.2. No effects were found with Cu concentrations of 0·5–1·5μg/ml medium. Between concentrations of 5 and 40μg Cu/ml medium, lengths and wet-weights of cartilage cultures decreased significantly (P< 0·001) compared with controls. The decrease was directly proportional to increasing Cu concentration, and that of the length was greater with increasing period of culture (P< 0·001).3. With 5–20μg Cu/ml medium cartilage and bone became yellow in colour, and chondrocytes were swollen, rounded and basophilic. They were detached from their lacunae and the quantity of matrix was reduced. Loss of alkaline phosphatase (EC3.1.3.1) activity and disappearance of glycogen accompanied the degeneration. Osteogenesis ceased, cells failed to divide and mature, lost their enzymes and died. Cu did not accumulate in the bone matrix.4. The direct toxic effects of Cu for cartilage and bone may underlie some of the skeletal changes in hepatolenticular degeneration (Wilson’s disease).5. As Zn concentrations were increased from 2·5 to 7·5μg/ml medium, lengths and wet-weights of cartilaginous cultures were significantly increased (P< 0·001). As Zn concentrations were further increased (from 10 to 40μg/ml medium), lengths and wet-weights were significantly decreased (P< 0·001).6. Zn stimulated chondrocyte division and vacuolation of cytoplasm. With higher Zn concentrations toxic changes of granular basophilia, lacunar detachment and necrosis were seen. Differentiation and functioning of osteoblasts, osteoclasts and chondroclasts were stimulated by Zn.7. Zn was found in bone matrix, osteoblasts, osteocytes and hypertrophied chondrocytes.

Growth of the Chick Embryo In Vitro

An improved technique is described for in vitro culture of the chick embryo from three days through 21 days of total incubation (three days in shell plus 18 days in culture). Mean survival time for cultured embryos is 18 days of total incubation, and mean morphological stage is Hamburger-Hamilton stage 41 (15 days). Mean measurements of wet weight, dry weight, and right third toe length for stage 45 (partial or complete abdominal yolk sac retraction, 19–20 days) cultured embryos are comparable with corresponding means for stage 42–43 (16–17 days) embryos from control intact eggs. Possible causes of growth retardation in vitro are briefly discussed.

Milk Production, Wet Weight, Dry Weight, Potassium, and Nucleic Acid Measurements of Cows’ Udders

Udders were from 15 dry and 35 lactating cows of several dairy breeds. After trimming, udders were weighed and 39-potassium, 40-potassium, dry fat-free tissue weight, deoxyribonucleic acid, and ribonucleic acid were determined. Simple correlation coefficients and linear regression coefficients were calculated for all 50 udders and for the 35 lactating udders, giving a total of 60 comparisons. The highest correlation was between wet weight and 39-potassium at .98 for all 50 udders while the correlation between deoxyribonucleic acid and milk production for the 35 lactating udders was only .22. For all udders deoxyribonucleic acid related highest to dry fat-free tissue weight with a correlation of .86. Milk production related highest to 39-potassium and ribonucleic acid with correlations of .70 in both comparisons. For every gram increase in udder 39-potassium, there was a 1.11kg increase in milk production. While deoxyribonucleic acid in lactating udders was 2.42 g/kg wet weight and 3.51 g/kg wet weight in dry udders, total deoxyribonucleic acid in lactating udders was 28.7g and only 16.0g in dry udders.

The influence of acute respiratory acidosis on the pulmonary defense mechanisms in rats.

Respiratory acidosis and infection often occur together. Because metabolic abnormalities can enhance susceptibility to respiratory infection, the effect of acute respiratory acidosis on murine resistance to bacterial infection was investigated. After infection with Staphylococcus aureus labeled with phosphorus-32, rats were anesthetized for 4 hours with gas mixtures containing 5, 8, or 10 per cent carbon dioxide with 30 per cent oxygen and 1 per cent halothane in nitrogen. Pulmonary bactericidal activity rates were determined in excised lungs. Bactericidal activity decreased progressively with increasing degrees of respiratory acidosis; arterial blood threshold values were pH 75 mm Hg. Hypoxia was not a factor (arterial oxygen tension > 88 mm Hg), and there was no significant base deficit. Pulmonary edema, as judged histologically and by wet and dry lung weight measurements, was not present. It was concluded that respiratory acidosis impairs pulmonary defense mechanisms...

Growth Rate of a Carangid Fish, the Omaka Caranx mate, in Hawaii

Abstract A study of growth rate was initiated to ascertain the time to marketable size and the feasibility for aquaculture of the Hawaiian carangid, Caranx mate. The growth rate of Caranx mate was calculated for larvae, juveniles, and adults. Measurements of standard length and wet weight of juveniles were made every 14 days for a year; of adults, every 30 days for 3 months. The approximate growth rate for larval C. mate was 18 mm per month; of juveniles, 7.5 mm per month; and of adults, 2.3 mm per month. Marketable size is reached in approximately 7 months.

Developmental Changes in Weight and Hemolymph Total Solids in the Sixth Instar of Peridroma saucia (Lepidoptera: Noctuidae)

In spring and winter generations of the variegated cutworm, Peridroma saucia (Hubner), female larvae are heaviest at the fourth day after the fifth ecdysis, their weight decreasing subsequently, but in summer generations their weight continues to increase until the sixth day. Spring and winter males show weight changes similar to those of females of the same generations, but the summer males, in contrast, maintain a constant weight from the fourth to the sixth day after ecdysis. In spring and winter generations, the hemolymph of female larvae has a higher refractive index than that of male larvae at the fourth and subsequent days after the fifth ecdysis, but in summer generations this difference is not evident until the sixth clay. The hemolymph refractive index increases during the prepupal stage. This is at variance with findings on various silkworm species which characteristically incorporate hemolymph proteins and amino acids into silk at this time. It is consistent with previously published work and the analysis of the present findings, to associate the variation in total wet weight and plasma refractive index with the interaction between progressive larval differentiation and metamorphosis phenomena. Upon these are superimposed fluctuations ascribed to sex, genetic change, and host-plant composition. The data obtained in this study suggest that, as a gauge of larval age in populations of healthy insects, plasma refractive index measurements may be more reliable than measurements of wet weight.