Influence of stress and stress-protecting factors on rat tolerance to cold and efficiency of rat adaptation to cold]

The adaptive characteristics of the body, including the specific features of increased cold resistance upon repeated exposures to cold, are determined not only by the properties of thermogenic structures themselves, but largely depend on the contribution of the central mechanisms which control the processes of habituation and mobilization of functions. The experiments revealed an increase in cold resistance in rats after preexposure to cold. Immobilization stress prior to training cold significantly decreased rapid cold resistance in the animals, but increased the training effect of the first cooling. On the contrary, chlordiazepoxide increased cold resistance during the first cooling. Testing of the untreated animal showed no effect of training. No adaptive changes in cold resistance occurred in rats with impaired amygdaloid complex. Analyzing adrenal catecholamines revealed a significant elevation of dopamine concentrations in the rats exposed to cold. Hypothalamic catecholamines did not change with cold and serotonin in intact rats and 5-hydroxyindoleacetic acid in amygdalectomized rats substantially increased.     

Metabolic and endocrine responses to cold air in women differing in aerobic capacity

PURPOSE: The purpose of this study was to measure resting metabolic rate, plasma norepinephrine, and plasma immunoreactive beta endorphin during exposures to cold air during two consecutive 5-d periods, separated by 2 weekend days, in two groups of women differing in aerobic fitness. METHODS: Plasma norepinephrine (NE), plasma immunoreactive beta-endorphin (IBE), and resting metabolic response (RMR) were measured during repeated exposures to 3.5 degrees C air in two groups of women differing in aerobic fitness. Ten women, separated into highly fit (HFW) and less fit (LFW) groups, sat in 22 degrees C air for 45 min followed by 45 min in 3.5 degrees C air each day during two consecutive 5-d periods separated by two weekend days. RESULTS: Norepinephrine was not different between groups during warm air exposure; however, following 45 min of cold air, NE was two times higher in HFW compared with that in LFW (P < 0.001). Plasma IBE was elevated (P < 0.02) in HFW compared with that in LFW but was not affected by exposure to cold on any test day. Warm RMR was not different between groups and remained unchanged during the study period. Cold RMR was significantly higher in LFW compared with that in HFW (P < 0.01). Resting metabolic rate peaked at 30% of VO2peak in LFW by the 5th minute of cold exposure on day 1 before declining to 21% and remaining steady. In contrast, RMR in HFW peaked at about 13% and then fell to 9.4% before slowly increasing to 14% by the end of 45 min. On other test days HFW RMR increased to 14% of VO2peak and rose slowly through 45 min of cold exposure while LFW RMR peaked at 24% of VO2peak before declining to 20% and remaining steady. CONCLUSIONS: Our findings suggest that, in women, aerobic fitness alters the endocrine and metabolic responses to acute cold air exposure. The norepinephrine response is exaggerated in highly fit women exposed to cold but not the metabolic response. Immunoreactive beta endorphin was not affected by exposure to cold but was elevated in highly fit women. We further conclude that the temperature threshold for acclimation to cold air by women may be higher than the air temperature used in this study.     

Shelf-life of pre-cooked rice oral rehydration salt packets

The shelf-life of pre-cooked rice oral rehydration salts (ORS) at the household level was studied in urban Dhaka. To prepare the packets, cooked rice was dried and ground to fine powder and the salt ingredients were mixed according to the World Health Organization formulation. For each half liter packet, 10 g glucose was replaced by 25 g of instant cooked rice powder. The packets were kept in different environments for three months among 30 households of varying socioeconomic status. At monthly intervals, two packets from each family were collected for laboratory tests. Physical characteristics of ORS such as color and dispersibility remained the same throughout the three month study period. However, in the third month flavor changed slightly. The electrolyte concentration of the prepared solution remained the same at the end of the first, second and third months. However, progressive but minimal increase in moisture content of the packets was noted over the allotted time period. This increase in moisture was less when the mixture was packed in double thin layer polythene bags as opposed to the single layer bags. In conclusion, the shelf-life of pre-cooked rice ORS remains stable at least up to three months when stored at the household level. Therefore, pre-cooked rice ORS can be kept at households for future use in the event of diarrheal episodes.     

Potential impacts of creating biomedical engineering programs on gender distribution within leading engineering colleges.

During the past decade, the number of biomedical engineering (BME) undergraduate degree programs that reported engineering bachelor's (BSE) degree recipients to the American Society for Engineering Education increased from 19 to 38 among the Association of American Universities institutions (AAUs). This increase in BME BSE degree recipients coincided with substantial decreases in the percentage of women receiving BSE degrees at the public AAUs. AAUs that had BME BSE degree recipients in 2000 or first reported BME graduates between 2000 and 2009 experienced a decrease in the percentage and number of women receiving engineering undergraduate degrees across the other engineering disciplines. Demographic data for public and private AAUs and within the four largest engineering disciplines, electrical and computer engineering, mechanical engineering, civil engineering, and chemical engineering show that the percentage and number of non-BME female BSE degree recipients decreased contemporaneously with an increase in the number of BME degree programs and BME BSE degree recipients. Academic leaders and diversity professionals should see the results presented here as cautionary. The targeting of science, technology, engineering, and mathematics disciplines toward specific underrepresented groups is discussed with respect to ongoing limited degree attainment of women in these fields. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Salt and oxidative stress: similar and specific responses and their relation to salt tolerance in citrus

Salt damage to plants has been attributed to a combination of several factors including mainly osmotic stress and the accumulation of toxic ions. Recent findings in our laboratory showed that phospholipid hydroperoxide glutathione peroxidase (PHGPX), an enzyme active in the cellular antioxidant system, was induced by salt in citrus cells and mainly in roots of plants. Following this observation we studied the two most important enzymes active in elimination of reactive oxygen species, namely, superoxide dismutase (SOD) and ascorbate peroxidase (APX), to determine whether a general oxidative stress is induced by salt. While Cu/Zn-SOD activity and cytosolic APX protein level were similarly induced by salt and methyl viologen, the response of PHGPX and other APX isozymes was either specific to salt or methyl viologen, respectively. Unlike PHGPX, cytosolic APX and Cu/Zn-SOD were not induced by exogenously added abscisic acid. Salt induced a significant increase in SOD activity which was not matched by the subsequent enzyme APX. We suggest that the excess of H2O2 interacts with lipids to form hydroperoxides which in turn induce and are removed by PHGPX. Ascorbate peroxidase seems to be a key enzyme in determining salt tolerance in citrus as its constitutive activity in salt-sensitive callus is far below the activity observed in salt-tolerant callus, while the activities of other enzymes involved in the defence against oxidative stress, namely SOD, glutathione reductase and PHGPX, are essentially similar.     

Expression of a betaine aldehyde dehydrogenase gene in rice, a glycinebetaine nonaccumulator, and possible localization of its protein in peroxisomes

BACKGROUND: Acquired resistance to standard chemotherapy for tuberculosis (TB) is an increasing problem worldwide. Vietnam has one of the highest incidences of TB and also has a large population of potential migrants to other countries. Since 1979 the International Organisation for Migration (IOM) has been running a supervised programme of TB treatment for intending migrants from Vietnam where few facilities for bacteriological culture and sensitivity testing exist. This study aimed to assess the most important factors for predicting non-response to first-line treatment as treatment starts and whether any further indicators occur during the course of treatment which may enable more accurate prediction of non-response. METHODS: In all, 130 subjects failing to respond to first-line therapy (cases) between 1990 and 1995 were compared with 673 subjects who responded to therapy (controls) on various demographic and clinical characteristics using logistic regression to create a prognostic index. Variables analysed included the patient history of past TB treatment, weight, age, sex and radiological and bacteriological findings. All subjects also tested negative for HIV status. RESULTS: The chief markers of successful response were x-ray signs and degree of sputum smear positivity. These markers provided a prognostic index with an optimal cutoff providing about 70% sensitivity and 80% specificity. Incorporating further measures obtained through the first 3 months of treatment improved the sensitivity to 80%. CONCLUSION: While this study enabled prediction of the majority of subjects failing to respond to first-line therapy, other factors need to be assessed before recommendations for altering treatment regimens can be made. The prognostic index could be useful in assessing subjects for closer supervision.     

Metabolic activation of 2-aminofluorene by isolated rat liver cells through different pathways leading to hepatocellular DNA-repair and bacterial mutagenesis

The aromatic amine 2-aminofluorene (2-AF) is metabolised by isolated rat liver cells to reactive species, thereby causing mutagenic effects in Salmonella typhimurium TA 1538 and evoking DNA-excision repair within the liver cells. The pathway leading to the production of metabolites mutagenic in Salmonella is likely to proceed via direct N-hydroxylation of 2-AF to N-hydroxy-2-aminofluorene (N-OH-2-AF). On the other hand, the formation of intermediates giving rise to hepatocellular DNA-repair is shown to depend upon N-acetylation of 2-AF to 2-acetylaminofluorene(2-AAF), whereas a subsequent conjugation reaction, most likely to be sulfate ester formation, is also essentially involved.     

国内外冷轧电工钢尺寸公差分析及探讨

大多数工业化国家的冷轧电工钢都采用IEC标准制定本国标准,在铁损、磁感相同的情况下,评价标准水平高低和质量优劣的主要指标就是电工钢的尺寸公差。经对IEC、欧洲、日本、中国、美国标准尺寸公差的比较得出:取向钢的同板差,IEC、欧洲、日本、中国相同;美国ASTM标准较严。无取向钢的同板差,美国最大,中国、日本中等,IEC、欧洲最小。取向钢的横向厚度差,IEC、欧洲标准严于日本、中国标准0.010mm;美国ASTM没有规定。无取向钢横向厚度差,IEC、欧洲标准较严,日本、中国较松。美国没有规定。宽度偏差,IEC、欧洲标准最小,美国最大,日本、中国中等。     

Metabolic engineering for the production of carotenoids in non-carotenogenic bacteria and yeasts

This article deals with a topic being controversially discussed in public for several years now: violence in school. Following the outlining of the current state of research and the naming of causes is a representation of the research-project "Violence in School' sponsored by the German Research Community (Deutsche Forschungsgemeinschaft, DFG). This four-stage program which was designed to analyze and prevent violence in school has set itself the aim to get a comprehensive idea of extent and appearance of violent behavior as well as to find condition-constellations in the school environment and also externally. Finally, some ideas for prevention and intervention of violence in school are given. Those recommendations represent a set of proposals that can be found in the bibliography.     

Metabolic delivery of ketone groups to sialic acid residues. Application To cell surface glycoform engineering

The development of chemical strategies for decorating cells with defined carbohydrate epitopes would greatly facilitate studies of carbohydrate-mediated cell surface interactions. This report describes a general strategy for engineering the display of chemically defined oligosaccharides on cell surfaces that combines the concepts of metabolic engineering and selective chemical reactivity. Using a recently described method (Mahal, L. K., Yarema, K. J., and Bertozzi, C. R. (1997) Science 276, 1125-1128), we delivered a uniquely reactive ketone group to endogenous cell surface sialic acid residues by treating cells with the ketone-bearing metabolic precursor N-levulinoylmannosamine (ManLev). The ketone undergoes highly selective condensation reactions with complementary nucleophiles such as aminooxy and hydrazide groups. The detailed quantitative parameters of ManLev metabolism in human and nonhuman-derived cell lines were determined to establish a foundation for the modification of cell surfaces with novel epitopes at defined cell-surface densities. Ketones within the glycoconjugates on ManLev-treated cells were then reacted with synthetic aminooxy and hydrazide-functionalized carbohydrates. The remodeled cells were endowed with novel lectin binding profiles as determined by flow cytometry analysis. The simplicity and generality of this method make it well suited for use in the study of carbohydrate-mediated cell surface interactions.     

A lea-class gene of tomato confers salt and freezing tolerance when expressed in Saccharomyces cerevisiae

Although less cytotoxic, the new platinum complex [meso-1,2-bis(2,6-difluoro-4-hydroxyphenyl)-ethylenediamine]sulfatopl atinum (II) (2) is equipotent to cisplatin (1) in the oestrogen-dependent MXT mammary tumour of the mouse. As this may be due to oestrogen level-lowering properties, we compared the effect of 1 and 2 on steroidogenesis in the rat. A single dose of 1 and 2 (20 mumol/kg s.c.) decreased plasma testosterone level in male rats by 90% (1, day 3) and 80% (2, day 7). Luteinizing hormone level remained unchanged in intact and in ovariectomized rats. The activities of the following testicular enzymes were decreased (day 7): cholesterol side-chain cleavage enzyme (1: 33%; 2: 36%), 3 beta-hydroxysteroid dehydrogenase/delta 4,delta 5-isomerase (1: 31%; 2: 48%) and 17 alpha-hydroxylase/17,20-lyase (1: 21%; 2: 15%). Testicular microsomal cytochrome P450 content was also diminished (1: 60%; 2: 49%, day 7). Corticosterone level in plasma and biosynthesis in adrenal explants was not affected, indicating the selectivity of action at the gonadal level. In vitro, neither 1 nor 2 (2 and 20 microM) influenced binding of human chorionic gonadotropin to testis interstitial cells during an observation period up to 21 h. These results suggest that 1 and 2 act at the gonadal level by inhibiting the expression of the steroidogenic enzymes. They do not, however, inactivate the luteinizing hormone receptor.     

Dual role for the yeast THI4 gene in thiamine biosynthesis and DNA damage tolerance

The bioactivity, i.e., bone-bonding ability, of 26 glasses in the system Na2O-K2O-MgO-CaO-B2O3-P2O5-SiO2 was studied in vivo. This investigation of bioactivity was performed to establish the compositional dependence of bioactivity, and enabled a model to be developed that describes the relation between reactions in vivo and glass composition. Reactions in vivo were investigated by inserting glass implants into rabbit tibia for 8 weeks. The glasses and the surrounding tissue were examined using scanning electron microscopy (SEM), light microscopy, and energy-dispersive X-ray analysis (EDXA). For most of the glasses containing < 59 mol % SiO2, SEM and EDXA showed two distinct layers at the glass surface after implantation, one silica-rich and another containing calcium phosphate. The build-up of these layers in vivo was taken as a sign of bioactivity. The in vivo experiments showed that glasses in the investigated system are bioactive when they contain 14-30 mol % alkali oxides, 14-30 mol % alkaline earth oxides, and < 59 mol % SiO2. Glasses containing potassium and magnesium bonded to bone in a similar way as bioactive glasses developed so far.     

Microstructure ‐ tensile strength correlation of salt bath nitrocarburised engineering steels

A commonly used engineering steel (En8) and a hot working die steel (H11) were salt bath nitrocarburised in the ferritic and austenitic range and studied for their microstructure and tensile properties. Compound layer thickness and hardness increased with increasing treatment temperature. There was a marginal improvement in the tensile strength after ferritic nitrocarburising due to the hardness increase in the compound layer and diffusion zone. There was marginal drop in the tensile properties of specimens treated in the austenitic range, but these values were comparable to those obtained after blank treatment at the same temperature. The tests showed that the compound layer had good cohesion with the underlying zone despite the precipitous hardness drop at their interface.     

Regulation of salt tolerance in fission yeast by a protein-phosphatase-Z-like Ser/Thr protein phosphatase

In the yeast Saccharomyces cerevisiae, Na+ efflux is mediated by the Ena1 ATPase, and the expression of the ENA1 gene is regulated by the Ppz1 and Ppz2 Ser/Thr protein phosphatases. On the contrary, in the fission yeast Schizosaccharomyces pombe, effective output of Na+ is attributed to the H+/Na+ antiporter encoded by the sod2 gene. We have isolated a S. pombe gene (pzh1) that encodes a 515-amino-acid protein that is 78% identical, from residue 193 to the COOH terminus, to the PPZ1 and PPZ2 gene products. Bacterially expressed Pzh1p shows enzymatic characteristics virtually identical to those of recombinant Ppz1p. When expressed in high-copy number from the PPZ1 promoter, the pzh1 ORF rescues the caffeine-induced lytic defect and slightly decreases the high salt tolerance of S. cerevisiae ppz1delta mutants. Disruption of pzh1 yields viable S. pombe cells and has virtually no effect on tolerance to caffeine or osmotic stress, but it renders the cells highly tolerant to Na+ and Li+, and hypersensitive to K+. Although lack of pzh1 results in a 2-3-fold increase in sod2 mRNA, the pzh1 mutation significantly increases salt tolerance in the absence of the sod2 gene, suggesting that the phosphatase also regulates a Sod2-independent mechanism. Therefore, the finding of a PPZ-like protein phosphatase involved in the regulation of salt tolerance in fission yeast reveals unexpected aspects of cation homeostasis in this organism.     

Metastasis of carcinoma to skeletal muscle leading to myosclerosis and progressive contractures

Pressure sore prevention is a challenging aspect of caring for elderly patients who have sustained femoral neck fractures. Despite implementation of a pressure sore prevention policy, a small-scale audit revealed that almost half of patients who sustained femoral neck fractures developed Stage 1 or Stage 2 pressure sores while in hospital. The findings indicate the need for more proactive pressure sore prevention in A&E and theatres.     

Secondary amenorrhea leading to osteoporosis: incidence and prevention

Osteoporosis is widely accepted as a "female disease" occurring primarily in postmenopausal women. The fact that this disease can affect premenopausal women experiencing menstrual dysfunction is less commonly known. Amenorrhea decreases bone density at an age when bone formation should still be occurring. The implications of this failure to attain sufficient bone density during the formative years are frightening. The adverse effects on skeletal strength may lead to devastating outcomes in this subgroup of women, either now or in the future. This article reviews causes, risk factors, and treatments associated with both osteoporosis and amenorrhea. Three causes of secondary amenorrhea are discussed in detail: rigorous physical training, anorexia nervosa, and use of the contraceptive agent medroxyprogesterone acetate injection. A review of the literature is presented in order to establish the link between amenorrhea and osteoporosis. A great many young women may be unknowingly placing themselves at risk for developing osteoporosis. This article includes interventions that may decrease this risk and improve quality of life.     

Genetic analysis of salt tolerance in arabidopsis. Evidence for a critical role of potassium nutrition

A large genetic screen for sos (for salt overly sensitive) mutants was performed in an attempt to isolate mutations in any gene with an sos phenotype. Our search yielded 28 new alleles of sos1, nine mutant alleles of a newly identified locus, SOS2, and one allele of a third salt tolerance locus, SOS3. The sos2 mutations, which are recessive, were mapped to the lower arm of chromosome V, approximately 2.3 centimorgans away from the marker PHYC. Growth measurements demonstrated that sos2 mutants are specifically hypersensitive to inhibition by Na+ or Li+ and not hypersensitive to general osmotic stresses. Interestingly, the SOS2 locus is also necessary for K+ nutrition because sos2 mutants were unable to grow on a culture medium with a low level of K+. The expression of several salt-inducible genes was superinduced in sos2 plants. The salt tolerance of sos1, sos2, and sos3 mutants correlated with their K+ tissue content but not their Na+ tissue content. Double mutant analysis indicated that the SOS genes function in the same pathway. Based on these results, a genetic model for salt tolerance mechanisms in Arabidopsis is presented in which SOS1, SOS2, and SOS3 are postulated to encode regulatory components controlling plant K+ nutrition that in turn is essential for salt tolerance.