Respective Control Values Research Articles

Heterogenous changes in neuropeptide Y, norepinephrine and epinephrine concentrations in the hearts of diabetic rats

The changes in concentrations of neuropeptide Y (NPY), norepinephrine and epinephrine were investigated in the rat hearts 1, 2, 4, 6, 9 and 12 months after administration of streptozotocin (STZ; 65 mg/kg i.v.). About 30% of diabetic animals displayed symptoms of partial spontaneous recovery, i.e. decreasing blood glucose levels and increasing insulin concentrations in the plasma and pancreas. NPY concentrations in the atria of diabetic rats did not differ from those in age-matched control rats 1, 2, 4, 6 months in the right atria and even 9 months after STZ in the left atria. However, uncompensated diabetes led to a significant decrease in NPY levels 9 and 12 months after STZ administration in the right and left atria, respectively. In the ventricles, NPY concentrations were significantly decreased 6 months after the onset of diabetes. Interestingly, partial spontaneous recovery of diabetes was associated with increased NPY levels in the atria. Myocardial norepinephrine concentrations increased 1 month after STZ and then declined reaching ∼ 60% of the respective control values 12 months after the onset of the disease. Partial spontaneous recovery of diabetes had no effect on norepinephrine concentrations. Myocardial epinephrine concentrations did not differ from those found in controls till month 9 of the disease and they became significantly lower at month 12. Partial recovery of diabetes resulted in epinephrine concentrations not differing from the control values at month 12 of diabetes. Regarding to preferential localization of norepinephrine in the sympathetic postganglionic fibers and that of NPY also in intrinsic ganglion neurons, intrinsic neuronal circuits seem to be less susceptible to STZ-induced damage than extrinsic nerves and they might be able to recover after amelioration of diabetes.

Capacity of Various Food Materials to Support Growth and Reproduction of Epigeic Earthworms on Vermicompost

Biomass production and reproduction of tropical epigeic earthworms (Eisenia fetida, Perionyx excavatus, and Dicogaster bolaui) were studied using in-situ vermicomposts to assess the suitability of different forest litters, i.e., Tectona grandis(teak), Madhuca indica(mahua), and Butea monosperma (palas) and crop residues, i.e., Triticum aestivum L. (wheat), Glycine max Merri. L. (soybean), and Brasica juncea L. (mustard) as food materials. The leaf litter of T. grandis and the wheat crop residue (T. aestivum L.) were found to be the most suitable food material for these earthworms. Comparisons of the survival and reproduction rate of three epigeic earthworms revealed that the higher reproduction rate was maintained in case of E. fetida compared to P. excavatus and D. bolaui in these vermicomposts. The progressive decrease in total organic carbon, C/N ratios, water-soluble carbohydrates, and biodegradability index was observed irrespective of treatments in the progressive stage of decomposition. The total organic carbon decreased significantly and C/N ratios narrowed down about 17 percent to 45 percent and water-soluble carbohydrates decreased to about 11 percent to 25 percent by the application of earthworms compared to control. Application of earthworms accelerated the decomposition of forest litters and crop residues, which ultimately resulted in larger cation exchange capacity/total organic carbon (CEC/TOC) ratios than their respective control values. The use of earthworm application accelerated the compost maturity in the order: T. grandis litter compost > wheat straw > Madhuca indica> B. monosperma > soybean straw > mustard straw compost. The lignin content of decomposed organic waste increased with maturation, and concomitant decrease of cellulose giving rise to higher lignin/cellulose ratios. Irrespective of earthworms inoculation, levels of available nutrient such as NH4-N, NO3-N and available P were increased significantly (p = < 0.05).

Hepatotoxic and haematological effects of Nigerian Bonny light crude oil in male albino rats

The effect of Bonny light crude oil was assessed in adult albino rats. The rats were administered with 200, 400, and 800 mg/kg of the crude oil orally for 7 days. Fluid intake was measured daily, and the initial and final animal body weight recorded. Oral crude oil at these doses produced no effect on feed and fluid intake between the test groups and the control group. There was a significant decrease in body weight compared to the control group after 7 days of treatment with the different doses of crude oil. The toxic effects of the liver and hematological effects were assessed. The packed cell volume (PCV) and total white blood cell (WBC) of the 200 mg/kg group were significantly decreased compared to the respective control values. Administration of 200, 400, and 800 mg/kg of Bonny light crude oil, caused a significant dose-dependent increase in glutamic oxaloacetic transaminase (GOT) and glutamic pyruvic transaminase (GPT) levels, but a significant decrease in the alkaline phosphatase (AP) level compared to the control. Histological examination indicates that crude oil induced severe pathologic changes in the forms of necrosis and oedema.

Influence of nutrient amendments on the phytoextraction of weathered 2,2‐bis(p‐chlorophenyl)‐1,1‐dichloroethylene by cucurbits

Field experiments were conducted to determine the impact of nutrient amendments on the phytoextraction of weathered 2,2-bis(p-chlorophenyl)-1,1-dichloroethylene (p,p '-DDE) by eight cultivars of cucurbits over a single growing season. Four cultivars of Cucurbita pepo ssp pepo are accumulators and extract percent level quantities of persistent organic pollutants (POPs), whereas C. pepo ssp ovifera and Cucumis sativus are nonaccumulators. The nonamended accumulators phytoextracted 1.0% of the p,p'-DDE and had a translocation factor of 0.44; however, the nonaccumulators removed 0.16% of the contaminant and had a translocation factor value of 0.09. The accumulators also had 3.8 times greater inorganic element content than the nonaccumulators. Duplicate mounds of each cultivar also received weekly nutrient amendments of phosphorus (400 mg/L K2HPO4), nitrogen (200 mg/L KNO3), or nitrogen/phosphorus (400 mg/L K2HPO4, 200 mg/L KNO3); a minus phosphorus treatment involved a 1-L addition of 1 g/L AlSO4 to the soil before planting. When normalized to respective control values (unamended vegetation), the root and stem p,p'-DDE bioconcentration factors (BCF) of the accumulator cultivars were significantly greater than those of the nonaccumulator cultivars under most nutrient regimes. The biomass of accumulator cultivars decreased by up to 61% under certain nutrient regimes, resulting in mixed effects on the amount of p,p'-DDE extracted. Treatment with N and P increased nonaccumulator biomass by 40 to 100%, and increased p,p'-DDE extraction from soil by 75%. Although generally assumed that fertilizer amendments will enhance phytoremediation, as evidenced here by the nonaccumulators, additions of macronutrients may reduce the phytoextraction of weathered POPs by C. pepo ssp pepo. These findings support our hypothesis that the ability of C. pepo ssp pepo to remove sequestered organic contaminants is governed by unique nutrient-acquisition mechanisms.

Natural occurrence of citrinin in rice grains and its biocontrol byTrichoderma hamatum

Paddy rice was sampled from El-Sharkia, El-Gharbia, El-Dakahlia and Kafr El-Shekh governorates, Egypt. Of the 30 samples taken, ten were contaminated with the mycotoxin citrinin. An average of 6.79 × 104 fungal spores per gram rice was found. The isolated fungi represented 47 species and 28 genera. The predominant genera wereAspergillus, Cladosporium andPenicillium. Aspergilli were represented by 22 species;Aspergillus niger andA. flavus had the highest occurrence.Penicillium viridicatum produced the highest amount of citrinin on glucose ammonium nitrate salts broth and rice grains, and hence this isolate was selected as a good producer of citrinin in this study. The presence ofTrichoderma hamatum reduced the amount of citrinin produced byP. viridicatum compared with its respective control. The excessive growth ofT. hamatum onP. viridicatum was increased with time. Viability ofP. viridicatum conidia decreased byT. hamatum with an increase in the incubation period. Chitinases and 1,3-β-glucanase enzyme activity ofT. hamatum increased with extending the incubation period onP. viridicatum mycelia up to maximum values at 72 and 84 h, respectively.T. hamatum led to a decrease in the production of citrinin byP. viridicatum on rice grains compared with the respective control values.

Potassium Deposition During And After Hypokinesia In Potassium Supplemented And Unsupplemented Rats

The aim of this study was to determine that hypokinesia (restricted motor activity) could increase potassium (K+) losses with decreased tissue K+ content showing decreased K+ deposition. To this end, measurements were made of K+absorption, tissue K+ content, plasma K+ levels, fecal and urinary K+ excretion during and after hypokinesia (HK) with and without K+ supplementation. Studies conducted on male Wistar rats during a pre-hypokinetic period, a hypokinetic period and a post-hypokinetic period. Rats were equally divided into four groups: unsupplemented vivarium control rats (UVCR), unsupplemented hypokinetic rats (UHKR), supplemented vivarium control rats (SVCR) and supplemented hypokinetic rats (SHKR). SHKR and UHKR were kept in small individual cages which restricted their movements in all directions without hindering food and water consumption. SVCR and UVCR were housed in individual cages under vivarium control conditions. SVCR and SHKR consume daily 3.96 mEq potassium chloride (KCl) per day. Absorption of K+, and K+ levels in bone, muscle, plasma, urine and feces and PA levels did not change in SVCR and UVCR compared with their pre-HK levels. During HK, plasma, fecal and urinary K+ levels and plasma aldosterone (PA) levels increased significantly (p<0.05) with time, while K+ absorption, muscle and bone K+ content decreased significantly (p<0.05) with time in SHKR and UHKR compared with their pre-HK values and the values in their respective vivarium controls (SVCR and UVCR). During the initial 9-days of post-HK, K+ absorption increased significantly (p<0.05) and plasma K+ levels, fecal and urinary K+ losses and PA levels decreased significantly (p<0.05) and muscle and bone K+ content remained significantly (p<0.05) depressed in SHKR and UHKR compared with their pre-HK and their respective vivarium control values. During HK and post-HK periods, K+ absorption, bone and muscle K+ content, and K+ levels in plasma, urine and feces and PA levels were affected significantly (p<0.05) more in SHKR than in UHKR. By the 15th day of post-HK the values in SHKR and UHKR approach the control values. The higher K+ losses during HK with decreased tissue K+ levels shows decreased K+ deposition. The higher K+ loss with lower tissue K+ levels in SHKR than in UHKR shows that K+ deposition decreases more with K+ supplementation than without. Because SHKR had shown lower tissue K+ content and lost higher K+ amounts than UHKR it was concluded that the risk of decreased K+ deposition and tissue K+ depletion is inversely related to K+ intake, i.e., the higher K+ intake, the greater the risk for decreased K+ deposition, and the higher K+ losses and the greater the risk for tissue K+ depletion. The dissociation between tissue K+ depletion and K+ excretion indicates decreased K+ deposition as the principal mechanism of tissue K+ depletion during prolonged HK.

RELATIONSHIPS AMONG PLASMA [2-13C]URACIL CONCENTRATIONS, BREATH13CO2EXPIRATION, AND DIHYDROPYRIMIDINE DEHYDROGENASE (DPD) ACTIVITY IN THE LIVER IN NORMAL AND DPD-DEFICIENT DOGS

Dihydropyrimidine dehydrogenase (DPD), the first enzyme in the sequential metabolism of pyrimidine, regulates blood concentrations of 5-fluorouracil and is deeply involved in its toxicity. This study was designed to examine the effects of a DPD inhibitor on blood concentrations of [2-(13)C]uracil ([(13)C]uracil) and (13)CO(2) concentration (Delta(13)C) expired in breath after oral or intravenous administration of [(13)C]uracil to DPD-suppressed dogs prepared by pretreatment with 5-(trans-2-bromovinyl)uracil (BVU), a DPD inhibitor. Area under the curve (AUC(t)) of [(13) C]uracil after oral administration at 20 micromol/kg to dogs pretreated with BVU at 2, 5, and 40 mmol/kg were 37-, 88- and 120-fold higher than those of the control dogs, respectively. In contrast, breath AUC(t) values of Delta(13)C were reduced to 0.88-, 0.47- and 0.13-fold the control values, respectively. Upon intravenous administration of [(13)C]uracil at 20 micromol/kg to dogs pretreated with BVU at 0.5, 2, and 40 micromol/kg, blood AUC(t) values of [(13)C]uracil were 1.4-, 4.2-, and 13-fold higher than those of the control group, respectively, whereas breath AUC(t) values were reduced to 1.0-, 0.83-, and 0.07-fold the respective control values. DPD activities in the liver cytosol of dogs pretreated with BVU at 0.5, 2, 5, and 40 micromol/kg were decreased to 0.71-, 0.12-, 0.06-, and 0.04-fold those of the control dogs, respectively. These findings demonstrate that breath output (Delta(13)C) is a good marker of hepatic DPD activity in vivo.

Primordial germ cell migration in the rat: preliminary evidence for a role of galactosyltransferase.

The precise cellular mechanism of primordial germ cell (PGC) migration remains unknown. Cell surface galactosyltransferase (GalTase) is known to play unique roles in the process of locomotion of many migratory cells. With an objective to seek evidence for possible involvement of GalTase in the migratory process of PGC, we evaluated germ cell migration in the rat following experimental modulation of embryonic GalTase activity. Pregnant rats were laparotomized under anesthesia on Day 10 of pregnancy. While embryos of one uterine horn received lysozyme (100 microg/fetus), those of the other received alpha-lactalbumin (LA; 100 microg/fetus), N-acetylglucosamine (GlcNAc; 250 nmole/fetus), uridine 5'-monophosphate (UMP; 2.5 micromole/fetus), uridine diphosphate-galactose (UDP-gal; 250 nmole/fetus), or a combination of 250 nmole of UDP-gal and 2.5 micromole of UMP/fetus. Between gestation Days 12 and 14, embryos were dissected out and processed for histochemical localization of PGC on the basis of binding of Dolichos biflorus agglutinin on the surface glycoconjugate of the germ cells. The number of PGC in each embryo was counted. There was a daywise increase in the number of PGC in all groups. As compared with lysozyme-exposed controls, the numbers of PGCs at the day-specific sites on all days of examination were significantly lower in the LA- as well as GlcNAc-exposed groups. UMP or UDP-gal individually exerted little or no influence, while the total PGC count rose significantly over the respective control values under simultaneous exposure to UMP and UDP-gal. The present findings suggest a likely catalytic role of GalTase in the process of germ cell migration.

The biomechanical properties of the healing periodontium of replanted rat mandibular incisors.

One of the most important aspects in tooth replantation seems to be restoration of the tooth support function of the healing periodontal ligament (PDL). We examined the support function, as measured by the mechanical properties, of the healing PDL at 7, 14, and 21 days after replantation of the left mandibular incisor in rats. From each dissected left mandible, a transverse section(650 microm in thickness) of the incisor was cut through an axis near the labial alveolar crest. Each section was intrusively loaded at a rate of 5 mm min(-1), and the shear stress-strain curve for the PDL was analyzed. Mechanical measures of the healing PDL showed gradual improvement after replantation. By 21 days, the mechanical strength returned to 53% of the control value; the extensibility, to 85%; the stiffness, to 61%; and the toughness, to 52%. The healing PDL exhibited reattachment of fibers in the middle region of the PDL, and the birefringent collagen fibers appeared to have regained the functional orientation by 14 days. The ratios occupied by the birefringent collagen fibers in the tooth-related, middle, and bone-related areas of the healing PDL gradually improved and returned to 78, 51, and 48% of the respective control values by 21 days. These results suggest that the support function of the healing PDL is gradually restored and that the biomechanical restoration is closely related to the reorganization and reorientation of collagen fiber bundles in replanted rat incisors.

Reducing swelling pressure on the freezing method of ground treatment by drilling and coring measures for tunnelling works

The Outer Metropolitan Discharge Channel Project was implemented to relieve flooding problem at the outskirts of Tokyo. Vertical Shaft No. 2 is one of the vertical shafts constructed in diluvial sand and clay formations. The ground treatment work by Freezing Method was used to create a frozen earth wall to prevent water seepage and collapse at the launching portal during dismantling of diaphragm wall and initial launching stage of the shield machine. After considering the design strength of frozen earth, lateral pressure and safety factor, the thickness of the frozen earth during dismantling of the diaphragm wall was designed as 4.8 m while for initial launching stage of shield machine, the thickness of the frozen earth from the entrance packing was designed as 7.95 m. Totally, about 3500 m3 of frozen earth were generated. Due to the existence of clay in the frozen earth, a higher swelling pressure to the clay layer resulting from freezing was anticipated to occur during construction. As a counter measure to protect the vertical shaft and diaphragm wall, drilling and coring was carried out into the ground formation to the full depth of clay layer and an additional two metres into the underlying sand layer. The drill holes absorbed the displacement due to swelling stemming from freezing thereby reducing the swelling pressure. In order to determine the degree of impact of swelling pressure on the vertical shaft and diaphragm wall as well as the efficacy of drilling and coring into the ground formation in relieving swelling pressure, the following factors of steel reinforcement stress and deflection of the diaphragm wall as well as displacement of the internal space of vertical shaft were measured. The measurement results revealed that drilling and coring had managed to keep the stress, deflection and displacement below the respective established control values. In addition comparison was made between: (1) average swelling pressure estimated from maximum deflection of diaphragm wall; (2) average swelling pressure estimated from displacement of internal space of the vertical shaft; and (3) average swelling pressure deduced from a theoretical equation proposed by Takashi without subject to drilling and coring. The results show that the average swelling pressure estimated from maximum deflection of diaphragm wall on the dismantling date of diaphragm wall (i.e. 85th day after the freezing operation commenced) was 12 tf/m2. This value is about 70% of 17 tf/m2 i.e. the average swelling pressure without drilling and coring as deduced from Takashi's equation. Furthermore, the average swelling pressure estimated from displacement of internal space of the vertical shaft on the 153rd day after the freezing operation started (i.e. when the frozen earth for initial launching of shield machine was ready) was 18 tf/m2, which was about 80% of 23 tf/m2 i.e. the average swelling pressure without drilling and coring as deduced from Takashi's equation. In conclusion, it was found that drilling and coring in ground formation had reduced the swelling pressure resulting from freezing to 70% to 80% of the case without drilling and coring. Thus, this has proven that drilling and coring in ground formation is an effective way to reduce swelling pressure stemming from freezing method of ground treatment. (A). Reprinted with permission from Elsevier. For the covering abstract see ITRD E124500.

Studies on the protective effects of caffeic acid and quercetin on chemical-induced hepatotoxicity in rodents

Caffeic acid and quercetin, the well-known phenolic compounds widely present in the plant kingdom, were investigated for their possible protective effects against paracetamol and CCl4-induced hepatic damage. Paracetamol at the oral dose of 1 g/kg produced 100% mortality in mice while pretreatment of separate groups of animals with caffeic acid (6 mg/kg) and quercetin (10 mg/kg) reduced the death rate to 20% and 30%, respectively. Oral administration of sub-lethal dose of paracetamol (640 mg/kg) produced liver damage in rats as manifested by the significant (P<0.01) rise in serum levels of aminotransferases (aspartate transaminase (AST) and alanine transaminase (ALT)) compared to respective control values. The serum enzyme values were significantly (P<0.01) lowered on pretreatment of rats with either caffeic acid (6 mg/kg) or quercetin (10 mg/kg). Similarly, the hepatotoxic dose of CCl4 (1.5 ml/kg; orally) also raised significantly (P<0.05) the serum AST and ALT levels as compared to control values. The same dose of the caffeic acid and quercetin was able to prevent CCl4-induced rise in serum enzymes. Caffeic acid and quercetin also prevented the CCl4-induced prolongation in pentobarbital sleeping time confirming their hepatoprotectivity. These results indicate that caffeic acid and quercetin exhibited hepatoprotective activity possibly through multiple mechanisms.

Determining shelf life by comparing degradations at elevated temperatures

The degradation of a biological product follows a specific pattern that depends on the kinetics of the chemical reaction. For most biological and pharmaceutical products, accelerated stability tests are preferred to establish shelf life. We describe a new approach for accelerated stability tests, for situations in which the Arrhenius equation is not appropriate. This approach consists of estimating stability at elevated temperatures and comparing these results with the stability estimates for a similar product with a known shelf life. In this article, "Test" refers to Immuno-Trol Low Cells, and "Control" (the product with a known shelf life) refers to Immuno-Trol Cells. The degradation rates and stabilities at elevated temperatures of three antigens of the Test are estimated and compared to their respective Control values. Most of the degradation occurs at the beginning of the experimental period and then slows down until it levels off to form a plateau at the minimum level. Both Control and Test showed similar degradation patterns at three elevated temperatures, indicating that they both have the same mechanism of degradation. Thus, it is expected that they will degrade similarly at storage temperature and have nonsignificantly different shelf lives. The approach for accelerated stability testing discussed here is applicable to situations in which the Arrhenius equation is not appropriate, and the chemical properties of both the Test and Control products are similar.

The effect of pentoxifylline on haemolysis in patients with double cardiac prosthetic valves

Objective — Intravascular haemolysis frequently occurs in patients with mechanical heart valve prostheses. In this prospective study, we investigated whether pentoxifylline (PTX) has an effect on haemolysis following prosthetic valvular replacement in 40 patients who underwent double valve (mitral and aortic) replacement.Methods and results — The patients were randomly assigned to two groups as control (n = 20) and PTX group (n = 20). PTX was given in a daily oral dose of 1200 mg (3 times 400 mg) for 120 days. Laboratory tests for evidence of haemolysis namely, haemoglobin (Hb), haematocrit (Hct), plasma total bilirubin, indirect bilirubin and haptoglobin levels, corrected reticulocyte percent and serum lactic dehydrogenase activity (SLDH) were performed before and after the PTX treatment. PTX treatment caused significant increases in Hb, Htc, and haptoglobin levels (P < 0.05, P<0.05 and P<0.01, respectively).Additionally, there were significant decreases in SLDH, total and indirect bilirubin levels, and corrected reticulocyte percent in patients receiving PTX as compared with their respective control values (P<0.01, for all). PTX treatment caused a significant improvement, to different extents, in signs of haemolysis in 60% of the patients. On the other hand, the response rate was 5% in the placebo-treated control group (P<0.05).Conclusions — These findings suggest that PTX may be an effective agent in the management of haemolysis in patients with prosthetic heart valves.

Cytokine expression in allergic inflammation: systematic review of in vivo challenge studies.

Allergic inflammatory responses are driven by cells of the immune system that rely on cytokines to regulate the activity of other immune and structural cells. To review published studies to (1) identify cytokines consistently increased after allergen challenge in atopic patients and (2) investigate temporal variation in cytokine expression. A PUBMED systematic search was used to extract data from studies involving analysis of cytokine expression in fluids or biopsies following in vivo allergen challenge in atopic patients. Data were extracted from 82 studies. There were no consistent reports of cytokine protein increase in fluids of patients at 0-1 h after challenge. At 4-12 h, the chemokines eotaxin, macrophage inflammatory protein-1alpha, RANTES (regulated on activation normal T cell expressed and secreted) and interleukin (IL)-8 have all been consistently reported to be up-regulated. At 18-24 h after challenge, the lymphokines IL-4, IL-5 and IL-13, as well as the pro-inflammatory cytokines granulocyte-macrophage colony-stimulating factor, tumour necrosis factor-alpha and IL-6 are consistently increased when compared with the respective control value. There were no reports of up-regulation in interferon-gamma protein and mRNA and in IL-2 mRNA. The expression of granulocyte-macrophage colony-stimulating factor is consistently increased in tissues at 4-12 h after challenge. The influence of this cytokine on antigen capture and presentation by dendritic cells should be further investigated. Additionally, allergen challenge studies are needed that investigate the expression of macrophage-derived chemokine and thymus-regulated and activation-regulated chemokine in tissues of atopic patients. Blocking the effects of these lymphocyte-specific chemokines might provide new therapeutic approaches for the control of allergic inflammation.

The interaction of carbachol and strophantin on the electrical and mechanical events in electrically driven strips of guinea pig left atria.

We compared the electrophysiological and the mechanical actions of the cholinergic agonist carbachol (CARB) and the digitalis glycoside strophantin (STR) in a study on the electrically driven strips of guinea pig left atria. The respective control values for the resting membrane potential (RMP), action potential amplitude (APA), action potential duration at 20%, 50%, and 90% repolarization levels (APD20,50,90), and time to peak tension (TtPt) were of the order of 61.1 +/- 1.69 nmV, 104.64 +/- 1.28 mV, 28.5 +/- 1.22 msec, 51.0 +/- 1.51 msec, 106.91 +/- 3.81 msec, and 60.1 +/- 1.09 msec. Exposure to CARB (2 x 10(-7) M) rapidly reduced contractility, TtPt, APD, and APA to exceptionally lower levels within the initial 5 minutes and gradually caused a slight hyperpolarization in RMP. Strophantin (1 x 10(-7) M) caused contractility and RMP to increase slightly, APD and APA to reduce less markedly, but did not significantly affect TtPt. Under the influence of combined CARB/STR, the effect of CARB on the contraction amplitude (CA), TtPt, APD, and APA was attenuated and that on RMP was significantly potentiated (p < 0.05), whereas the effects of STR on CA, TtPt, APD, and APA were reversed (p < 0.05), and the effect on RMP was augmented. The action potential duration was less responsive to STR at all depolarization levels with respect to those of CARB and combined CARB/STR. Although the correlation between the time course of APD-20 and APD-90 for STR was poor, the correlation for CARB and combined CARB/STR was highly significant (r > 0.95). The correlation between the effects of CARB on CA and APD-90 was high but poor for the effect of combined CARB/STR. Striking to note is that the rate of induction of contractile changes with CARB (d(delta)/dt = 1.39 +/- 0.05%/sec), and its washout was more rapid (p < 0.05) in comparison to the rate of changes in APD-90 (0.98 +/- 0.05%/sec). This result, however, was not observed with combined CARB/STR. From the results we concluded that CARB and STR act as antagonists when used in combination, with the exception that only the effect on RMP was additive, with asignificant discordance between the rates of induction of effects on CA and APD-90, with the former being more rapid.

Protective effects of atypical antipsychotic drugs on PC12 cells after serum withdrawal.

Atypical antipsychotic drugs are widely used in the treatment of schizophrenia, and clinical evidence has shown that early and prolonged intervention with these drugs will improve the long-term outcome. It is still unclear, however, whether the atypical antipsychotic drugs are also neuroprotective. To clarify this matter, we used PC12 cell cultures and the MTT assay for cell viability to determine whether various concentrations of the atypical antipsychotics clozapine, quetiapine, and risperidone are neuroprotective after serum withdrawal. In addition, to explore the drugs' actions, Northern blot was used to examine the gene expression of SOD1 (Cu/Zn superoxide dismutase) and p75NTR (p75 neurotrophin receptor). The results demonstrated that 1) the antipsychotic drugs can protect PC12 cells from death after serum withdrawal; cell viability in these drug treatment groups is significantly different from that in the groups without serum in the medium (P < 0.01); and 2) these drugs up-regulated the SOD1 gene expression to more than 120% (P < 0.05) and also down-regulated p75NTR mRNA levels to less than 65% of their respective control values (P < 0.05). These findings suggest that the atypical antipsychotics clozapine, quetiapine, and risperidone may exert a neuroprotective function through the modulation of SOD1 and p75NTR expression.

Intraspecific variability in growth response to cadmium of the wood-rotting fungus Piptoporus betulinus

The intraspecific variability in growth response to cadmium (Cd) on agar media and in liquid culture was studied among fourteen strains of a wood-rotting fungus Piptoporus betulinus. The variability of Cd tolerance was found to be very high. The ED50 ranged from 6.8 μM Cd in the most sensitive strain, up to 255.1 μM in the most resistant one. On agar media the addition of Cd to nutrient media resulted in reduction of relative growth rate and increased lag time. While the reduction of growth rate was already apparent at 10 μM Cd, the lag time was significantly increased in higher Cd concentrations. Five strains of P. betulinus failed to grow at 250 μM Cd and none grew at 500 μM metal. Biomass production in liquid culture was less sensitive to addition of Cd than the growth rate on solid media. At 100 μM Cd the radial growth rate of the mycelium was reduced to 27%, whereas the dry mass of mycelium was 77% of the respective control value. A group of four Cd-sensitive strains was found, showing low metal tolerance both on solid media and in liquid cultures. Although the isolates originated from sites with different Cd-pollution level, no correlation between level of Cd-pollution and resistance (ED50) was found. The growth rate of fourteen tested strains displayed lower variability than biomass production, showing that radial growth rate is more species-specific and therefore more valuable for interspecific comparisons of growth response.

Acrylamide disturbs the subcellular distribution of GABAA receptor in brain neurons.

Mechanisms underlying the action of acrylamide on neurons were studied by monitoring the expression of GABA(A) receptor (R) in cultured brain neurons derived from chicken embryos. In situ trypsinization of the neurons and 3H-flunitrazepam binding assay were employed to examine the subcellular distribution of GABA(A)R. A 3-h exposure of the cultured neurons to 10 mM of acrylamide raised reversibly the proportion of intracellular (trypsin-resistant) 3H-flunitrazepam binding sites by about 48% and decreased cell surface binding 24% from respective control values, without altering total cellular binding and the affinity of the ligand. Moreover, the acrylamide treatment induced more intense perikaryal immunostaining of GABA(A)R alpha subunit proteins than that in control neurons but did not change the total level of cellular alpha immunostain, in accordance with the binding data. In the cell bodies of acrylamide-treated neurons, the level of neurofilament-200 kDa proteins was similar to control, whereas the tubulin protein content was significantly lowered approximately 51% from control, as revealed by quantifying the immunostained cytoskeletal elements. In addition, electron microscopic observations found reductions in the numbers of microtubules and neurofilaments in the perikarya of acrylamide-treated neurons. As exhibited by the 3H-leucine and 3H-monosaccharide incorporation experiments, the exposure to acrylamide inhibited the rate of general protein synthesis in the culture by 21%, while the rate of glycosylation remained unaltered. Furthermore, in situ hybridization analysis showed that acrylamide did not modify the expression of GABA(A)R alpha subunit mRNAs. Taken together, these data suggest that acrylamide may downregulate the microtubular system and disintegrate neurofilaments, and thereby block the intracellular transport of GABA(A)R, resulting in the accumulation of intracellular receptors.

Fluid distribution measurement between body compartments in primates in disclosing fluid retention during prolonged hypokinesia.

Body fluid homeostasis undergoes significant changes during hypokinesia (diminished movement). Understanding of fluid transfer between body fluid compartments and its regulating mechanisms was the aim of this study for disclosing impaired fluid retention during hypokinesia (HK). Studies were done on 12 male Macaca mulatta (rhesus monkeys) aged three to five years (5.15 to 6.56 kg) during 90 days period of pre-HK and 90 days period of HK. All primates were divided equally into two groups: vivarium control primates (VCP) and hypokinetic primates (HKP). Hypokinetic primates were kept for 90 days in small individual cages that restricted their movements in all directions without hindering food and fluid intakes. Control primates were housed in individual cages without their movements being restricted. Total body fluid (TBF), intracellular fluid volume (IFV) and circulating plasma volume (CPV) decreased significantly (p < 0.05), while extracellular fluid volume (EFV) and interstitial fluid volume (IsFV) decreased significantly (p < 0.05) at the initial seven days of the HK period and after the 7th day increase progressively in HKP compared with their pre-HK values and their respective control values in VCP. Fluid excretion, urinary and plasma sodium (Na) and potassium (K) levels increased significantly (p < 0.05), while fluid intake and fluid retention decreased significantly (p < 0.05) in HKP compared with their pre-HK values and their respective controls in VCP. The measured parameters did not change in VCP compared with their pre-HK values. It was concluded that decreased IFV and CPV may demonstrate fluid depletion, while marked increase of fluid loss despite of fluid depletion may demonstrate impair fluid retention during HK. Dissociation between fluid loss and fluid depletion may demonstrate the presence of reduced fluid retention as the mechanism of development of fluid depletion during HK.

An Estimation of the Potential Prevalence of "Syndrome X" amongst Diabetics Using Traditional Markers

In order to estimate the potential prevalence of "Syndrome X" in newly diagnosed cases of insulinoplethoric diabetes mellitus, patients were selected from the emergency (accident) ward, University of Benin Teaching Hospital, Benin City, Nigeria. Both risk factors (plasma lipids) and allied metabolic aberration (plasma glucose and creatinine) were assessed in 100 subjects comprising of 60 patients (30 males, 30 females) within the ages of 35 to 70 years and 40 sex and age matched healthy control subjects. Results showed significant increase in patients mean plasma glucose, tricyglycerol and total cholesterol when compared with the respective mean control values at the 5% probability level, using ANOVA. Their lipoprotein-cholesterol profile also, showed a significant difference (P