UDP-galactose 4-epimerase from Escherichia coli: existence of a catalytic monomer

UDP-galactose 4-epimerase from Escherichia coli is a homodimer of molecular mass 39 kDa/subunit and requires NAD as a co-factor. X-ray crystallographic studies indicate two pyridine nucleotide co-factor-binding sites of the dimeric molecule situated in a symmetry-oriented manner. Size-exclusion HPLC of an equilibrium intermediate at 3 M urea suggests a monomeric holoenzyme structure that is catalytically active. Ultracentrifugal studies of the native enzyme in a 5-20% sucrose gradient at low protein concentration also indicate existence of a catalytic monomer. The monomer resembles the dimeric protein in stability and most of its physico-chemical properties.

A study of ocular morbidity among elderly population in a rural area of central India

A cross-sectional study was conducted in five randomly selected villages in Wardha district of Maharashtra state to study the magnitude and factors related to the prevalence of ocular diseases among the elderly population. A total of 903 persons above 50 years were screened. The prevalence of low vision was 32% while that of blindness was 12.2%. Ocular morbidity rate was 1.21 lesions per elderly person and it increased significantly with increasing age (p < 0.001). Ocular diseases were found to be more prevalent among males, low socio-economic status group and landless labourers (p < 0.001). There was a high prevalence of refractive errors (40.8%), cataract (40.4%), aphakia (11.1%) followed by pterygium (5.2%), glaucoma (3.1%) and corneal opacities (3%). Prevalence of diseases of the lens and iris increased significantly with increasing age (p < 0.001). There is a need to evolve strategies for reducing the burden of ocular diseases and improve geriatric eye health under the existing infrastructure of health care delivery in our country.

Magnitude of acute respiratory infections in under five children

A community based study was carried out in a rural area of Wardha district in Maharastra to measure the incidence of acute respiratory infections among children below 5 years age. 384 under five children were followed up fortnightly for one calendar year to estimate the incidence of acute respiratory infections (ARI). There were 1298 episodes of ARI averaging 3.67 episodes/child/year. The incidence of lower respiratory infections was 0.07 episodes/child/year. The incidence of ARI was found to be closely associated with nutritional status of the child, socio-economic status of the family, maternal literacy status and family size. Environmental factors like type of house, ventilation and fuel used for cooking were found to influence the incidence of ARI.

Association of endogenous steroid levels with high and low density lipoprotein concentrations in the human maternal-fetoplacental unit at term

OBJECTIVE

To determine the concentrations of high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C), estradiol (E2), dehydroepiandrosterone (DHEA) and dehydroepiandrosterone sulfate (DHEAS) in both maternal and venous cord blood upon delivery at term; to determine the degree of association between lipoprotein cholesterol concentrations and concentrations of selected steroid hormones, thus indicating correlations between regulatory mechanisms mediating steroid biosynthesis and cholesterol homeostasis in the maternal-fetoplacental unit; and to determine the efficacy of both heparin-manganese precipitation and agarose-gel electrophoresis techniques for quantitation of HDL-C and LDL-C in fetal and maternal plasma.

STUDY DESIGNS

Steroids were quantitated by radioimmunoassay in maternal and umbilical cord venous blood collected from 56 patients upon delivery. Correlation analysis and ANOVA were utilized to determine the degree of association between quantitative parameters in the total study population and differences in regard to fetal sex, respectively.

RESULTS

Values determined for all parameters measured fell within previously established normal ranges. HDL-C concentrations in the cord blood of female newborns were higher than those of males, while LDL-C concentrations were unchanged in regard to fetal sex. Concentrations of both LDL-C and all steroids measured in the maternal periphery were unchanged in regard to fetal sex, but HDL-C concentrations were higher in plasma of women bearing female fetuses. Further, LDL-C levels in cord blood positively correlated with maternal DHEAS levels and negatively correlated with maternal E2 levels. Cord E2 concentrations correlated highly with cord levels of both DHEA and DHEAS, and maternal E2 levels correlated, although to a lesser degree, with maternal DHEA concentrations.

CONCLUSION

The results indicated both positive and negative correlations of lipoprotein cholesterol levels with concentrations of the various steroid hormones associated with human pregnancy and illustrate the complicated interplay of mechanisms regulating steroid/lipoprotein metabolism in the maternal-fetoplacental unit. Changes in lipoprotein levels in the maternal-fetoplacental unit may suggest changes in steroid metabolism associated with fetal sex. Both heparin-manganese precipitation and agarose-gel electrophoresis techniques proved adequate for the quantitation of plasma lipoprotein cholesterol in both maternal and fetal plasma.

Clinical and electroneurophysiological assessment of leprosy patients on dapsone monotherapy--a two year follow-up study

Fifty-three persons with tuberculoid type of leprosy having a thickened nerve on one side and a clinically normal nerve on the contralateral side were studied before, during and after two years of therapy for electrophysiological abnormalities in apparently normal and in obviously thickened nerves. Twenty-seven patients had received treatment with dapsone 100 mg orally and 26 cases had received rifampicin therapy. It was found that there was no extension of anesthesia or diminution of motor power over a period of two years. There was no significant difference between the initial and final recordings of motor and sensory nerve conductions if aggregate figures were taken. However, taking individual cases, deterioration in nerve conduction (increased latency and decreased velocity) was found in two patients, of whom one had received dapsone and the other had received rifampicin.

Visual appearance of matte surfaces

All visual sensors, biological and artificial, are finite in resolution by necessity. As a result, the effective reflectance of surfaces in a scene varies with magnification. A reflectance model for matte surfaces is described that incorporates the effect of macroscopic surface undulations on image brightness. The model takes into account complex physical phenomena such as masking, shadowing, and interreflections between points on the surface, and it predicts the appearance of a wide range of natural surfaces. The implications of these results for human vision, machine vision, and computer graphics are demonstrated with both real and rendered images of three-dimensional objects. In particular, objects with extremely rough surfaces produce silhouette images devoid of shading, precluding visual perception of the object's shape.

Epidemiological aspects of visual impairment above 50 years in a rural area

A cross-sectional survey was conducted in 5 villages in central India to find out the extent, causes and epidemiological factors for visual impairment among 903 individuals aged above 50 years; 44.3% of them were visually impaired (29.4% with low vision and 14.9% blind). Age-specific visual impairment increased at a rate of 13.2% with each decade of advancing age. Landless labourers suffered more from visual impairment than other occupational groups (p < 0.05). Socioeconomic and literacy status of the population did not significantly influence the prevalence of visual impairment. Major causes of visual impairment were cataract (48.5%), refractive errors (24.5%), age-related macular degeneration (10%), glaucoma (6.8%), and others (10.2%). In view of the high prevalence of visual impairment among the elderly individuals, it is necessary to intensify our efforts in motivating them for early detection and treatment.

Oscillating behavior of carbohydrate granule formation and dinitrogen fixation in the cyanobacterium Cyanothece sp. strain ATCC 51142

It has been shown that some aerobic, unicellular, diazotrophic cyanobacteria temporally separate photosynthetic O2 evolution and oxygen-sensitive N2 fixation. Cyanothece sp. ATCC strain 51142 is an aerobic, unicellular, diazotrophic cyanobacterium that fixes N2 during discrete periods of its cell cycle. When the bacteria are maintained under diurnal light-dark cycles, N2 fixation occurs in the dark. Similar cycling is observed in continuous light, implicating a circadian rhythm. Under N2-fixing conditions, large inclusion granules form between the thylakoid membranes. Maximum granulation, as observed by electron microscopy, occurs before the onset of N2 fixation, and the granules decrease in number during the period of N2 fixation. The granules can be purified from cell homogenates by differential centrifugation. Biochemical analyses of the granules indicate that these structures are primarily carbohydrate, with some protein. Further analyses of the carbohydrate have shown that it is a glucose polymer with some characteristics of glycogen. It is proposed that N2 fixation is driven by energy and reducing power stored in these inclusion granules. Cyanothece sp. strain ATCC 51142 represents an excellent experimental organism for the study of the protective mechanisms of nitrogenase, metabolic events in cyanobacteria under normal and stress conditions, the partitioning of resources between growth and storage, and biological rhythms.

Acute renal failure following jering ingestion

We report two cases of acute renal failure that followed the ingestion of jering. Features of jering poisoning included clinical presentation of bilateral loin pain, fever, nausea, vomiting, oligo-anuria, haematuria and passage of sandy particles in the urine. Blood urea (40.8 mmol/l; 21.9 mmol/l) and serum creatinine (1249 mumols/l; 693 mumols/l) were markedly elevated. With conservative therapy which included rehydration with normal saline and alkalinisation of the urine with sodium bicarbonate, the acute renal failure resolved.

Modulation of murine in vitro immune response by verapamil (V)

Functionally distinct lymphocyte subsets differ with regard to necessary activation signals. In selected circumstances lymphocyte activation has been shown to be critically dependent upon transcellular calcium influx. Whether calcium plays a central role in the activation of all lymphocytes remains to be determined. The effect of the calcium channel blocker verapamil on the induction of murine cytotoxic T lymphocytes (CTL), suppressor cells, T helper cells, and B cells was investigated. Verapamil (V) was found to inhibit the induction of cytotoxic effector cells. V acted primarily on the afferent limb of this immune response, was synergistic with cyclosporin A (CsA), and its effects could be largely reversed by the addition of exogenous helper factors. V also inhibited B cell proliferation in response to anti-mouse IgM in the presence of 2-mercaptoethanol, but in the absence of cognate or non-cognate T cell help. In contrast to this, V did not inhibit the activation of cells capable of inducing B cell proliferation nor did it inhibit the induction of suppressor cells. The selective suppression of V is discussed in terms of activation requirements of CTL, suppressor cells and helper cell subsets.

Vitamin A intake and vitamin A deficiency in rural children

The prevalence of vitamin A deficiency was estimated in 366 rural children in the age group of 1 to 15 years. In a systematically selected subsample of 90 children, the dietary intake of vitamin A was assessed. The prevalence of vitamin A deficiency signs ranged from 24.1 to 34.8%. The adequacy of dietary intake of vitamin A ranged from 8 to 12% when compared with the recommended dietary allowance. The dietary intake of children with and without vitamin A deficiency was not different (p greater than 0.05). The main source of beta carotene in the diet was cereals accounting for 47.9% of the total beta carotene intake.

Primary school teacher as a primary health care worker

School children (1608) were examined for three items (nails, scalp hairs and teeth) relating to personal hygiene and relevant infective conditions from two sets of villages i.e. one set where primary school teacher was working as primary health care worker (Group I) and the other set where Community Health Volunteer (CHV) was delivering primary health care (Group II). The objective was to evaluate the efficiency of school teachers' role vis-a-vis CHVs' in imparting health education to school children. Out of 1608 school children, 801 belonged to Group I villages and the remaining 807 to Group II villages. From the results, it was evident that children of Group I villages were better with respect to all the items related to personal hygiene and infective conditions excepting scalp infections, where difference was not statistically significant, indicating teachers' superiority over the CHVs' in imparting health education to school children.

Mechanism of durable resistance: a new approach

Wheat genotypes, including backcross derivatives of 'Thatcher' carrying Lr10 and Lr23, substitution lines for Lr10 and Lr23 in Chinese Spring background and Chinese Spring and Thatcher were analysed against 21 pathotypes of leaf rust in seedling tests. Adult plant responses in all these stocks were observed in the field nurseries under exposure to the inoculum of the Indian virulent races of leaf rust. The seedling data demonstrated that both the substitution lines and the backcross derivatives for each gene carry identical pattern of infection for resistance. The high level of adult plant resistance in the substitution lines, in contrast to the backcross derivatives in Thatcher, has been postulated to be due to the combination of resistance contributed by Lr10 and adult plant Chinese Spring resistance or to Lr23 and Chinese Spring adult plant resistance. It has been suggested that genes Lr10 and Lr23 added to the Chinese Spring background provide sources for durable resistance, since Chinese Spring has continued to provide a moderate level of adult plant resistance to leaf rust for a very long time.