The prediction of organ viability: I. An hypothesis

The metabolic consequences of ischemia have been studied in the clamped rat kidney, by measurement of tissue adenine nucleotide levels and it has been found that the levels of these compounds correlate well with the subsequent ability of the rat kidney to support life. Based on these results a general hypothesis has been proposed which suggests that the primary defect in the ischemically damaged organ is the inability of the cell to maintain adequate levels of adenine nucleotides.     

Histological structure of the testes in andropause]

A structure of the convoluted tubuli, spermatogenesis and number of Leydig's cells in the andropause have been analysed in dependence on the degree of symptoms intensity. A control group included otherwise healthy men with ++post-inflammatory azoospermia. A percentage of the convoluted tubuli with normal tissue (p < .002) and spermatogenesis (p < .001) has been significantly decreased in andropause. The number of Leydig's cells has not differed in andropause and in a control group (p < .05). No difference of significance have been noted in the structure of convoluted tubuli, spermatogenesis, and Leydig's cells number depending on the intensity of symptoms. FSH and LH levels have been significantly increased in andropause (p < .001). No relationship between FSH and LH levels and percentage of the abnormal convoluted tubuli has been observed. However there have been a relationship between FSH and LH levels and the number of abnormal convoluted tubuli with spermatogenesis inhibition and intensified clinical symptoms. There has also been a relationship between FSH and LH levels and Leydig's cells number in patients with marked symptoms of andropause.     

Amyloid Beta Peptides Affect Pregnenolone and Pregnenolone Sulfate Levels in PC-12 and SH-SY5Y Cells Depending on Cholesterol

Increased amyloid beta (AB) peptide concentration is one of the initiating factors in the neurodegeneration process. It has been suggested that cholesterol induces the synthesis of AB peptide from amyloid precursor protein or facilitates the formation of amyloid plaque by lowering the aggregation threshold of the peptide. It is also shown that AB peptides may affect cholesterol metabolism and the synthesis of steroid hormones such as progesterone and estradiol. Pregnenolone (P) and pregnenolone sulfate (PS) are the major steroids produced from cholesterol in neural tissue. In toxicity conditions, the effect of AB peptides on P and PS levels has not yet been determined. Furthermore, it has not been clearly defined how changes in cellular P and PS levels affect neuronal cell survival. The aim of this study was to determine the effects of AB peptides on cellular changes in P and PS levels depending on the level of their main precursor, cholesterol. Cholesterol and toxic concentrations of AB fragments (AB 25–35, AB 1–40 and AB 1–42) were applied to PC-12 and SH-SY5Y cells. Changes in cellular cholesterol, P and PS levels were determined simultaneously in a dose—and time-dependent manner. The cell viability and cell death types were also evaluated. AB peptides affected both cell viability and P/PS levels. Steroid levels were altered depending on AB fragment type and the cholesterol content of the cells. Treatment with each of the AB fragments alone increased P levels by twofold. However, combined treatment with AB peptides and cholesterol increased P levels by approximately sixfold, while PS levels were increased only about 2.5 fold in both cell lines. P levels in the groups treated with AB 25–35 were higher than those in AB 1–40 and AB 1–42 groups. The cell viabilities were significantly low in the group treated by AB and cholesterol (9 mM). The effect of AB peptides on P levels might be a result of cellular self-defense. On the other hand, the rate of P increase might be playing a key role in the cell death mechanism of AB toxicity depending on cellular cholesterol levels.     

Influence of thyroid status on the differentiation of slow and fast muscle phenotypes

Muscle phenotype is determined by combined effects of intrinsic genetic and extrinsic factors like innervation, hormonal levels and mechanical factors or muscle activity. We have been studying the effect of altered thyroid hormone levels on the expression of myosin heavy chain (MyHC) isoforms in control and regenerating soleus and extensor digitorum longus muscles of euthyroid, hypothyroid or hyperthyroid female inbred Lewis rats. The fiber type composition has been determined according to the mATPase activity and immunocytochemical staining of MyHC isoforms, the content of MyHC isoforms has been determined by SDS-PAGE, the mRNA levels have been measured by RT-PCR and the ultrastructural transformation has been analyzed by electron-microscopy. Our results indicate that although the innervation plays a decisive role in the determination of muscle phenotype, levels of thyroid hormones contribute to the extent of muscle phenotype transformation.     

Cytogenetic damages in the cells of allergy patients

The levels of cytogenetic damages in cell cultures of chemical industry workers suffering from different forms of allergy have been investigated. The levels of chromosomal aberrations in cells of allergic patients are shown to reliably increase as against those of healthy donors. Studies on SCE levels have shown no such differences between the patients and donors. The SCE levels have been determined at different periods of BUdR addition and cultures fixation under the effect of environmental factors.     

Effects of boron on nitrogen metabolism and sugar levels of sugar beet

Summary The effects of deficient and toxic levels of boron on various aspects of nitrogen metabolism in sugar beet are studied. Plant analysis shows a nitrate ion accumulation, a decrease in the activity of the nitrate reductase enzyme and a lower molybdenum absorption.The effect of boron levels on the plant and root sugar concentration has also been studied.     

The effect of daily Hassles of humoral immunity: an interaction moderated by locus of control

Research has shown that stress is associated with depressed cellular immune functioning. Controversy exists as to whether humoral immunity shows a similar depression under stress. Several psychological variables have been found to moderate responses to stress. In particular, an internal locus of control has been correlated with better health. The present study examined the level of salivary immunoglobulin A (IgA) and health locus of control in subjects with high and low stress levels. The Hassles scale was administered to identify two subject groups differing significantly in reported stress levels. Results showed no significant differences between the two groups on salivary IgA. There was a significant negative correlation between IgA and internal locus of control. The direction of this correlation is in contrast with previous findings on internality. The evidence suggests that high internal individuals may be especially vulnerable to high levels of stress, particularly stress that they cannot control. Also, there was a significant difference in IgA levels between females depending on whether they were in the first or the second half of their menstrual cycle. Those in the premenstrual phase had lower IgA levels.     

Dopaminergic processes in the striatum mediating corticoliberin effect on behavior of active and passive rats

The action of intranasal corticotropin-releasing hormone (CRH) administration on open field behavior and striatal and hypothalamic levels of dopamine, noradrenaline and their metabolites has been studied in rats with different behavior strategies (KHA and KLA strains). In KLA rats, CRH administration resulted in increased locomotor and exploratory activity, while KHA rats demonstrated decreased that. The analysis of catecholamine levels did not detect any strain differences in hypothalamus, but in striatum the dopamine levels have been twice higher, while the metabolite levels (DOPAC and HVA) were significantly lower in KLA rats as compared to KHA rats. The CRH administration led to increased dopamine and noradrenaline levels in hypothalamus and decreased those in striatum in rats of both strains, but in KLA the decrease was more evident. It is probably a result of intensified mediator turnover induced by the neurohormone in KLA rats, as supported by a fact of increased dopamine metabolite levels in this structure.     

The effect of daily hassles of humoral immunity: An interaction moderated by locus of control

Research has shown that stress is associated with depressed cellular immune functioning. Controversy exists as to whether humoral immunity shows a similar depression under stress. Several psychological variables have been found to moderate responses to stress. In particular, an internal locus of control has been correlated with better health. The present study examined the level of salivary immunoglobulin A (IgA) and health locus of control in subjects with high and low stress levels. The Hassles scale was administered to identify two subject groups differing significantly in reported stress levels. Results showed no significant differences between the two groups on salivary IgA. There was a significant negative correlation between IgA and internal locus of control. The direction of this correlation is in contrast with previous findings on internality. The evidence suggests that high internal individuals may be especially vulnerable to high levels of stress, particularly stress that they cannot control. Also, there was a significant difference in IgA levels between females depending on whether they were in the first or the second half of their menstrual cycle. Those in the premenstrual phase had lower IgA levels.     

The effects of sodium arsenate on the free amino acid levels in erythrocytes and plasma in rats.

The effects of arsenate on the levels of free amino acids in rat plasma and red blood cells have been investigated. The biggest changes occur in the branched-chain amino acids valine, isoleucine and leucine which are markedly decreased. The levels of several other amino-acids also change. The effects on the amino acids are not due to a change in the food intake caused by dosing with arsenate. This has been shown by comparing the results with those on fasting rats (40 h). Branched-chain amino acids in particular are markedly increased in plasma of fasting rats as opposed to a decrease in arsenate-treated rats.     

Maintenance of normal serum calcium level in the hyperprolactinaemic rat.

The effect of experimentally induced chronic hyperprolactinaemia in male rats on the serum levels of calcium has been examined. Chronic elevation of circulating prolactin levels had no significant effect on the serum calcium levels and normal blood calcium homeostasis was still maintained.     

Elevated Levels of Thymidylate Synthase Linked to Neoplastic Transformation of Mammalian Cells

Thymidylate synthase (TS), an enzyme that is essential for DNA synthesis and repair has been identified as an important biomarker for colorectal and other human cancers. The elevated steady-state levels of TS found in many common human malignancies have been thought to represent a secondary event in tumor formation. However, it has recently been demonstrated that the deregulated levels of ectopic TS may also have a causal effect on tumorgenesis since overexpression of human TS transforms immortalized mammalian cells to a malignant phenotype. Since the levels of TS are regulated by E2F-1 and thus are linked to the cell cycle pathway, regulating TS activity may be an important factor for the control of cell cycle progression and for the development of therapeutic strategies and cancer prevention.     

Accumulation and remobilization of amino acids during senescence of detached and attached leaves: in planta analysis of tryptophan levels by recombinant luminescent bacteria

The process of leaf senescence is biochemically characterized by the transition from nutrient assimilation to nutrient remobilization. The nutrient drain by developing vegetative and reproductive structures has been implicated in senescence induction. The steady-state levels of amino acids in senescing leaves are dependent on the rate of their release during protein degradation and on the rate of efflux into growing structures. To determine the possible regulatory role of amino acid content in leaf senescence, an in planta non-destructive, semi-quantitative method for the analysis of endogenous levels of free amino acids has been developed. The method is based on in vivo bioluminescence of amino acid-requiring strains of recombinant Escherichia coli carrying the lux gene. The luminescence signal was found to be proportional to the levels of added exogenous tryptophan and to the free amino acid levels in the plant tissues analysed. During the senescence of tobacco flowers and of detached leaves of oats and Arabidopsis, a progressive increase in the levels of free amino acids was monitored. By contrast to the detached leaves, the attached oat leaves displayed a decrease in the levels of free amino acids during senescence. In Arabidopsis, both the attached and detached leaves exhibited a similar pattern of gradual increase in amino acid content during senescence. The differences between the sink-source balance of the two species and the possible relationships between amino acid content and leaf senescence are discussed.     

Simple radio-immunoassay for the measurement of human and rat IgE levels by ammonium sulfate precipitation.

A simple assay for quantitating IgE levels has been developed based on the observation that antibody-bound IgE is insoluble in 33 percent saturated (NH-4)2-SO-4 whereas unbound IgE is not. The method has been applied to human and rat IgE. Some preliminary results on IgE levels in parasite-injected rats are presented.     

Small differences in Drosophila tropomyosin expression have significant effects on muscle function.

The effects of promoter deletions on Drosophila tropomyosin I (TmI) gene expression have been determined by measuring TmI RNA levels in transformed flies. Decreases in RNA levels have been correlated with rescue of flightless and jumpless mutant phenotypes in Ifm(3)3 mutant transformed flies and changes in muscle ultrastructure. The results of this analysis have allowed us to identify a region responsible for 20% of maximal TmI expression, estimate threshold levels of TmI RNA required for indirect flight and jump muscle function, and obtain evidence suggesting that sarcomere length may be an important determinant of flight muscle function.     

Components of the protein quality control system are expressed in a strain-dependent manner in the mouse hippocampus

Inbred mouse strains are used in forward-genetic experiments, designed to uncover genes contributing to their highly distinct neurophenotypes and multiple reports of variations in mutant phenotypes due to genetic background differences in reverse-genetic approaches have been published. Information on strain-specific protein expression-phenotypes however, is limited and a comprehensive screen of an effect of strain on brain protein levels has not yet been carried out. Herein a proteomic approach, based upon two-dimensional gel electrophoresis (2-DE) coupled to mass spectrometry (MALDI-TOF/TOF) was used to show significant genetic variation in hippocampal protein levels between five mouse strains. Considering recent evidence for the importance of the intracellular protein quality control system for synaptic plasticity-related mechanism we decided to focus on the analysis of molecular chaperones and components of the ubiquitin-proteasome system. Sixty-six spots, depicting 36 proteins have been unambiguously identified by mass spectrometry. Quantification revealed strain-dependent levels of 18 spots, representing 12 individual gene products. We thus present proteome analysis of hippocampal tissues of several mouse strains as suitable tool to address fundamental questions about genetic control of protein levels and to demonstrate molecular networks of protein metabolism and chaperoning. The findings are useful for designing future studies on these cascades and interpretation of results show that data on brain protein levels cannot be simply extrapolated among different mouse strains.     

The effects of metabolic stress on plasma progesterone in healthy volunteers and schizophrenic patients.

A number of preclinical studies suggest that progesterone may play an important role in the stress response, however, the effects of stress on progesterone in humans has not been established. Also, several lines of evidence indicate that schizophrenia may be associated with abnormal neurobiological responses to stress, but the effects of stress on progesterone in schizophrenia has not been investigated. The purpose of the present study was to examine the effects of stress on plasma progesterone and cortisol in healthy subjects and to determine if schizophrenic patients have altered stress-induced plasma progesterone levels compared to normal controls. Stress was induced through administration of 2-deoxyglucose (2DG), a glucose analog that impairs glucose metabolism resulting in a clinical state comparable to hypoglycemia. There were significant increases in plasma progesterone and cortisol levels following 2DG-induced glucoprivic stress in healthy controls. There was no relationship between stress related progesterone and cortisol elevations. Schizophrenic patients, in comparison to controls, had significantly greater 2DG-induced elevations in progesterone levels but no differences in stress-related cortisol levels. There was evidence that basal progesterone and cortisol levels were elevated in the schizophrenic patients. The implications of these data are discussed.     

Exposure to beta-carbolines norharman and harman

The aromatic beta-carbolines norharman and harman have been implicated in a number of human diseases including Parkinson's disease, tremor, addiction and cancer. It has been shown that these compounds are normal body constituents formed endogenously but external sources have been identified. Here, we summarise literature data on levels of norharman and harman in fried meat and fish, meat extracts, alcoholic drinks, and coffee brews. Other sources include edible and medicinal plants but tobacco smoke has been identified as a major source. Exposure levels from these different dietary sources are estimated to a maximum of 4 microg norharman per kg body weight (bw) per day and 1 microg harman per kg bw per day. Exposure via tobacco smoke depends on smoking habits and type of cigarettes but can be estimated to 1.1 microg/kg bw for norharman and 0.6 microg/kg bw for harman per package of cigarettes smoked. Studies on toxicokinetics indicate that inhalative exposure leads to a rapid increase in plasma levels and high bioavailability of norharman and harman. Oral bioavailability is lower but there are indications that sublingual absorption may increase dietary uptake of beta-carbolines. Endogenous formation can be estimated to be 50-100 ng/kg bw per day for norharman and about 20 ng/kg bw per day for harman but these rates may increase with high intake of precursors. Biomarker studies on plasma levels of beta-carbolines reported on elevated levels of norharman, harman or both in diseased patients, alcoholics and following tobacco smoking or consumption of beta-carboline-containing food. Cigarette smoking has been identified as major influence but dietary exposure may contribute to exposure.     

Fructose 2,6-bisphosphate in liver of Sparus aurata: influence of nutritional state

1. Fructose 2,6-bisphosphate (fru-2,6-P2) has been measured in liver and muscle of gilthead sea bream fish, Sparus aurata. 2. The fru-2,6-P2 levels in liver depend on the diet given to the fish: in fish fed a high carbohydrate diet, the fru-2,6-P2 levels are higher than any one previously reported. These changes are associated with differences in the phosphofructokinase 2 activity. 3. Fru-2,6-P2 levels has also been measured in liver of Sparus aurata after different fasting periods. In starved fish, fru-2,6-P2 did not decrease as sharply as in rat. The values found in fish starved for 20 days were similar to those reported for rats that had been starved for 24 hr.     

Subculture-induced protein synthesis in tissue cultures of Glycine max and Phaseolus vulgaris

The effects of subculture of tissue cultures on the levels of certain mRNAs have been investigated, and the action of cytokinins on the disposition of certain mRNAs between possible non-translating and translating pools has been determined. mRNA preparations were assayed by cell free translation with message-dependent reticulocyte lysate and the in vitro products resolved by polyacrylamide gel electrophoresis. Subculture of the cells caused a rapid stimulation of polysome formation. It also increased the translatable levels of a small group of mRNAs, one of which was present in both bean and soybean cultures. Cytokinins caused a slight increase in polysome levels after subculture, but had no effect on the levels of particular mRNAs, nor on the distribution of mRNAs between a non-translating and translating pool, nor on polysome levels in the absence of subculture.Abbreviations EDTA ethylenediaminetetra acetic acid - EGTA 1,2-di-(2-aminoethoxy)ethane-NNNN-tetra acetic acid - IEF isoelectric focusing - SDS sodium dodecyl sulphate