Showing papers by "Rajesh Kumar published in 1996"

Immunolocalization of polycystin in human tissues and cultured cells.

Abstract: The gene PKD I, which is mutated in type I autosomal dominant polycystic kidney disease (ADPKD 1), encodes a large protein of novel structure and unknown function and distribution that has been named polycystin. To gain better insight into polycystin function, we raised a panel of antisera against synthetic peptide antigens derived from the unique portion of the predicted polycystin sequence. Antisera were used to immunolocalize the protein in a variety of normal human fetal, childhood, and adult tissues as well as kidney and liver tissue from individuals with ADPKD 1, the genetically distinct ADPKD 2, and acquired renal cystic disease (ARCD). Subcellular localization studies were carried out on human cultured cell lines of renal epithelial origin. In normal tissues, polycystin expression was noted in renal tubular epithelial cells from 20 weeks gestation to 4 years postpartum, and in hepatocytes and biliary epithelium up to 4 years, but not in adult kidney or liver. Expression also was present in fetal and childhood pancreas, myocardium, bowel, and adrenal medulla. In cell lines of renal epithelial origin, immunofluorescence and immunoelectron-microscopical studies showed localization of polycystin epitopes to the peripheral cytoplasm. Kidney and liver from four unrelated adults with known ADPKD 1 showed strong staining, which was not seen in kidney and liver from one adult with ADPKD 2 or in kidney from three patients with ARCD. We conclude that polycystin is expressed in renal tubular epithelial cells as well as a variety of other cell types during development and growth but is absent or weakly expressed in adult kidney and liver. Overexpression of polycystin epitopes within affected tissue may be a specific feature of some or all cases of ADPKD 1.

Separation of 7-methyl- and 7-(2-hydroxyethyl)-guanine adducts in human DNA samples using a combination of TLC and HPLC

Abstract: We have used a combination of thin-layer chromatography (TLC) and high pressure liquid chromatography (HPLC) to achieve separation of 32 P-postlabelled 7-methylguanine and 7-(2-hydroxyethyl)-guanine adducts. The level of these two adducts was determined in human total white blood cells (mean values 0.7 to 1.5 adducts per 10 7 normal nucleotides) and isolated lymphocytes (mean values 1.1 to 12 adducts per 10 7 normal nucleotides). The separation of these two adducts revealed that the level of 7-(2-hydroxyethyl)-guanine was twice the level of 7-methyl-guanine adducts in total white blood cells, whereas, in isolated lymphocytes it was at least four times more than the 7-methylguanine adduct. The combined level of these two adducts in the lymphocytes of non-smokers was 1.1 to 8.4 adducts per 10 7 normal nucleotides and in the lymphocytes of smokers, the level was 5.6 to 12 adducts per 10 7 normal nucleotides. We also report detection of three unidentified adducts in the samples analysed, and at least one of these adducts seemed to be related to smoking. The chromatographic behaviour and depurination at neutral pH indicated the probable 7-alkylguanine or 3-alkyladenine nature of these unidentified adducts.

7-Alkylguanine adducts of styrene oxide determined by 32P-postlabelling in DNA and human embryonal lung fibroblasts (HEL)

Abstract: The modified 32P-postlabeling method was used for the detection of N-7-(2-hydroxy-phenylethyl) guanine adducts in DNA and human embryonal lung (HEL) cells treated in vitro with styrene oxide (SO). The total recovery of 7-alkylguanine adducts of styrene oxide in DNA analysed by 32P-postlabeling assay was 4.1 +/- 0.6%. The disappearance of 7-alkyldeoxyguanosine monophosphate adducts from SO-modified DNA at 37 degrees C showed a half-life of 19 h. The levels of 7-alkylguanine DNA adducts and single-strand breaks (SSBs) in DNA were determined in HEL cells treated with SO for 3 and 18 h. In the 3 h treatment there was a concentration-dependent increase of both 7-alkylguanine adducts and SSBs in DNA (r = 0.98, P = 0.012 and r = 0.99, P = 0.003, respectively). We found a significant correlation between 7-alkylguanine DNA adducts and SSBs in DNA (r = 0.98, P = 0.011). In HEL cells approximately 3-fold higher levels of both 7-alkylguanine DNA adducts and SSB in DNA were found after the SO (100 microM) treatment for 3 h than after the treatment for 18 h. A significant concentration-dependent increase was found only for SSB ( r = 0.95, P = 0.024) in the 18 h treatment with SO. There was no significant correlation between 7-alkylguanine adducts and SSBs (r = 0.72, P = 0.15). Our data suggest relatively fast removal of both 7-alkylguanine adducts of SO and DNA SSBs.

Application of 3D registration for detecting lesions in magnetic resonance breast scans

Abstract: In this paper we present 3D registration techniques for detecting breast cancer lesions based on differences between the high spatial resolution 'pre' and 'post' contrast administration MR breast scans. We also present registration techniques for detecting lesions based on the time course of enhancement after administration of the contrast agent based on changes in the low spatial resolution, high temporal resolution, dynamic MR data taken during the absorption of the contrast agent. Alignment of the 'pre' and 'post' MR data and of the dynamic MR images is done by a direct optimization technique to estimate a global affine deformation model using a coarse-to-fine control strategy over a 3D pyramid. This global model is followed by a one iteration flow estimation to account for any local non-rigidity. We present results of the registration process and visualization of the difference volumes obtained after alignment.

Nutritional status of children: validity of mid-upper arm circumference for screening undernutrition.

Abstract: OBJECTIVES: To determine the nutritional status and validity of mid upper arm circumference (MAC) in diagnosing malnutrition among preschool children. DESIGN: Cross-sectional household survey. SETTING: 47 villages in District Ambala, Haryana. SUBJECTS: 3747 children aged less than six years. METHODOLOGY: Trained field workers recorded age, weight, length/ height and MAC of children. Prevalence of underweight, stunting, and wasting were calculated in reference to National Centre for Health Statistics (NCHS) standards. Sensitivity and specificity of MAC for detecting underweight, wasting and stunting among children aged 1 to 4 years were determined. RESULTS: At the cut-off level of < -2.00 SD of Z-scores, 48.8% children were stunted, 49.6% were underweight and 9.1% were wasted whereas 47.6% children had neither wasting nor stunting. Prevalence of severe stunting, underweight, and wasting (Z-score < -3 SD) was 18.1%, 11.5% and 0.6%, respectively. Undernutrition showed a significant rise after 12 months of age (p < 0.0001). Stunting and underweight were significantly more among girls compared to boys (p < 0.01) but wasting was not significantly different in them. Compared to the conventional MAC cut off levels of < 13.5 cm and < 12.5 cm, sensitivity and specificity in our setting were optimum at < 13.5 cm for detection of wasting and < 14.0 cm for diagnosis of underweight and stunting, and < 13.0 cm for detection of severe wasting and < 13.5 cm for diagnosis of severe underweight and severe stunting. CONCLUSIONS: Almost every second child was undernourished. Optimum cut off level of MAC in our setting were higher than the conventional cut off points for detection of undernutrition among children.

Awareness of AIDS among school children in Haryana.

Abstract: The study is aimed to assess the existing level of knowledge of school children of 9th and 10th classes about Acquired Immune Deficiency Syndrome (AIDS). Three high schools in an urban area and three in the villages of a district of North India were included in the study. A pretested closed-ended questionnaire was administered to 336 students available. Overall level of knowledge about AIDS was found to be high. However, there were significant differences in knowledge among rural-urban and male-female students. There were some misconceptions in knowledge regarding transmission, prognosis and prevention. Books and media were the most common sources of information. Most of the students wanted to learn more about AIDS. Since overall knowledge levels were high we conclude that AIDS education should concentrate on clarifying areas of misconceptions.

Synthesis of 5-(1-azidovinyl) and 5-[2-(1-azirinyl)] analogs of 2′-deoxyuridine

Abstract: The regiospecific addition of bromine azide to the vinyl substituent of 5-vinyl-3′,5′-di-O-acetyl- (or tert-butyldimethylsilyl)-2′-deoxyuridines (2) yielded the corresponding 5-(1-azido-2-bromoethyl)-3′,5′-di-O-protected-2′-deoxyuridines (3). Treatment of the 5-(1-azido-2-bromoethyl) compounds 3 with t-BuOK, to effect the base-catalyzed elimination of HBr, afforded the corresponding 5-(1-azidovinyl)-2′-deoxyuridines (4, 7). Thermal decomposition of 5-(1-azidovinyl)-2′-deoxyuridine (7) at 110 °C in dioxane yielded 5-[2-(1 -azirinyl)]-2′-deoxyuridine (9). 5-(1 -Azidovinyl)-2′-deoxyuridine (7) exhibited appreciable in vitro antiviral activities againist herpes simplex virus type 1 (HSV-1) and varizella zoster virus (VZV). Athough 7 increased the length of survival of HSV-1 brain-infected mice, it did not decrease the mortality rate relative to placebo. 5-[2-(1-Azirinyl)]-2′-deoxyuridine (9) was an inactive antiviral agent. Key words: azidovinyl, azirinyl, 2′-deoxyuridine, antiviral activity.

Plasma vitamin A, zinc and selenium concentrations in children with acute and persistent diarrhoea.

Abstract: Plasma zinc, selenium, and vitamin A concentrations in 25 children with persistent diarrhoea (PD) and acute diarrhoea (AD) were determined and compared with 25 age-matched control children. Plasma retinol concentrations (PRC) and plasma zinc concentrations (PZC) (3.92 pg/dL and 79.4 pg/dL respectively) were found to be significantly lower (p<0.05) in children with PD. PZCs were also significantly reduced (p<0.05) in children with AD. However, reduction in PZC was more in PD than that in AD. There was no significant difference in PSC in children with either types of diarrhoea as compared with the control group. The results of the study showed that there was deficiency of vitamin A and zinc in diarrhoeas which needs to be correlated for proper nutritional management.

Thrombolytic therapy in infants for femoral artery thrombosis following cardiac catheterisation.

Abstract: Little information is available on the use of thromobolytic therapy in infants for femoral artery thrombosis after cardiac catheterisation. We report 12 cases (mean age: 4 months; range: 1-9 months) who received intravenous streptokinase (3000 U/kg bolus, 1000 U/kg/h) infusion. Five of them had undergone transarterial balloon dilatation procedures. Streptokinase was administered 48 h after catheterisation and continued for 4-20 h (mean 11.5 h). No detailed haematologic monitoring was done during therapy. Distal pulses were restored in all the patients. No complications were seen except a minor local ooze in two patients. We found that intravenous streptokinase is a safe and effective therapy for femoral artery thrombosis following cardiac catheterisation in infants.

32P-Postlabelling of diastereomeric 7-alkylguanine adducts of butadiene monoepoxide

Abstract: The reaction of 3,4-epoxy-1-butene (BMO) with deoxyguanosine-3'-monophosphate (3'-dGMP) resulted in the formation of two pairs of diastereomeric 7-alkyl-3'-dGMP derivatives corresponding to two isomers C?-1 and C?-2. The T4 polynucleotide kinase-mediated phosphorylation with [gamma-32P]-ATP showed preferential labelling of diastereo- mers of the C?-1 isomer. The diastereomers 1 and 2 of the C?-1 isomer had labelling efficiencies of 42%. However, the labelling efficiencies of diastereomers 3 and 4 of the C?-2 isomer were 11 and 10%, respectively. The 32P-postlabelling of BMO-modified DNA yielded four isomers in the ratio of 4:4:1:1 with overall recoveries being 14%. The two isomers had a half-life of 270 min (C?-1 isomer) and 300 min (C?-2 isomer) which is in accordance with the stability predicted by other similar adduct experiments. The molecular modelling experiments showed more pronounced restricted rotation of butadiene residue in C?-2 isomers due to steric interaction between butadiene residue at N-7 and O(6) atom of guanine than in C?-1 isomer. The butadiene residue also leads to steric overcrowding at 3'-phosphate in C?-2 isomer which probably restricts the access to the active site of T4 polynucleotide kinase.

Accuracy of maternal perception of neonatal temperature.

Abstract: Neonatal hypothermia is a common and widespread problem even in tropical developing countries(l,2) Majority of the deliveries in these countries are conducted at home either by traditional birth attendants or by relatives Therefore, methods of prevention of neonatal hypothermia, ie, warming the delivery room, wiping and wrapping the baby, and early maternal skin-to-skin contact are being popularized among them(3) Early recognition of hypothermia and prompt rewarming in home births is equally important Mothers often assess hypothermia by touching and feeling the temperature of the baby Studies in hospital settings have demonstrated that physicians and trained assistants can perceive the temperature of the newborn with reasonable accuracy by touching the skin of the baby(4-6) However, accuracy of mothers' assessment of the temperature of the baby by means of touching is not known This study was therefore designed to determine the accuracy of mothers'

Effect of Pore Alignment on Surface Wave Propagation in a Liquid-Saturated Porous Layer over a Liquid-Saturated Porous Half-Space with Loosely Bonded Interface.

Abstract: Dispersion of Rayleigh type surface waves have been studied in a liquid-saturated porous solid layer over a liquid-saturated porous half-space having a loosely bonded interface with the effect of pore alignment. Some special cases have been deduced by changing the depth of the layer. Frequency equation in the form of a determinant has been obtained. Dispersion curves giving phase and group velocities as a function of wave number have been plotted graphically for four different cases with a particular model.

Future research directions in the use of biomarkers.

Abstract: Many DNA adduct studies have been carried out in occupational groups that have been at a risk of cancer based on epidemiological results relating to exposure decades ago. Even new epidemiological publications on cancer cannot accurately address the effective exposures after about 1970. This is one justification for biomarker studies. Another justification is exposures for which epidemiological studies have not been conducted or have provided inadequate results, in spite of suspicions raised by short-term or animal experiments. The modulation of environment carcinogenesis by host polymorphism in genes for xenobiotic metabolizing and DNA repair enzymes is currently under extensive investigation. The studies relating phenotype/genotype to cancer are presently extended to various end points that may be related to cancer such as DNA adducts and cytogenetic damage. Adjustment for a metabolic phenotype or genotype may also increase the precision in the measurement. Mutations in oncogenes and tumor suppressor genes may give clues to the etiology of cancer.

Conjunctival impression cytology with transfer (CICT) to detect pre-clinical vitamin A deficiency among slum children in India.

Abstract: In order to establish a method usable in the field for diagnosis of pre-clinical vitamin A deficiency, conjunctival impression cytology with transfer (CICT) was used in 200 normal slum children aged 6-120 months in Chandigarh, India. Conjunctival impressions taken on cellulose acetate paper were transferred to glass slides which were fixed in ethanol and stained with alcian blue and carbol fuchsin. Sixty samples of cellulose acetate paper were preserved after transfer of impression and were stained later. Transfer was complete in forty-eight samples and in the other twelve it was incomplete. Conjunctival impressions on paper and slide of these twelve cases were comparable. At a plasma retinol concentration of < 0.70 mumol/l measured by HPLC the sensitivity, specificity and positive predictive values of CICT were 90.59%, 100% and 100% respectively. Compared with conventional conjunctival impression cytology, CICT is less time consuming, cheaper and comparable in validity. It is thus more suitable than the conventional method for mass screening.

Statistical Choropleth Cartography in Epidemiology

Abstract: Background: The potential of maps in the study of regional variation and similarlity in health and in understanding the underlying processes is being increasingly realized. It has thus become important that more care is exercised in drawing health maps and the subjective elements are minimized. Conventional choropleth maps based on quantitative data are mostly arbitrary with regard to the number of categories and the cutoff points. This can lead to substantially different pictures based on the same data set. Methods: We suggest use of cluster methods to discover 'natural' groups of data points which to a large extent are suggested by the data themselves. These methods can determine not only the cutoff points but also the number of categories required to depict the variability In the data. The methods have natural extension to the multivatlate set-up and thus can provide the strategy to construct integrated maps based on the simultaneous consideration of several variables. Since different cluster methods can yield different groupings we propose a simple method to identify cutoffs common to a majority of the methods. Results: The details of the methods are explained on two real data sets. One is the indicators of mortality before one year of age in India and the other is years of life lost due to premature mortality in different countries. The maps obtained are compared with the conventional maps. Conclusion: The cutoff points obtained by a majority of cluster methods deserve attention for obtaining natural groups for choroplethic depiction. Maps based on such cutoffs seems to have promise for increasing the accuracy in perception and cognition of regional variation.

Primary tuberculosis of esophagus.

Abstract: Primary tuberculosis of the esophagus is rare. We report a young lady with odynophagia who had esophageal tuberculosis without evidence of the disease elsewhere in the body.

Measurements of frequency upconversion and picosecond excitation‐correlation luminescence spectra in GaAs quantum wells and determination of time constants describing exciton dynamics

Abstract: We study the picosecond dynamics of free carriers and excitons in high‐quality GaAs quantum wells at 8 K using frequency upconversion (UC) and nonlinear picosecond excitation‐correlation (PEC) luminescence spectroscopy under nonresonant excitation conditions with carrier densities of a few 1010 cm−2. We analyze the measurements using a theoretical model of the coupled free electron–hole pair and exciton dynamics, incorporating important density‐dependent nonlinear effects, caused by exciton collisions and fermion exclusion. The time‐resolved UC photoluminescence (PL) spectra are used to deduce time constants related to free electron–hole (e–h)‐pair transformation into excitons and exciton transfer from large K to small K (k is the exciton wave vector). It is shown that unambiguous determination of exciton radiative and nonradiative decay times are possible when both UC and PEC PL spectra are considered simultaneously. We carry out a detailed line‐shape analysis of the picosecond UC and PEC PL spectra. We ...

A quantum structure for high‐temperature operation of AlGaAs lasers: Multiple‐quantum barrier and multiple‐quantum well in active region

Abstract: We propose a quantum structure of AlGaAs lasers designed for high‐temperature operation. In this design, the superlattice structure multiple‐quantum barrier (MQB) is located in the middle of active region which improves the injection efficiency of holes from the cladding into the active region, compared to MQB in cladding structure. Simulation results showed that low energy electrons can tunnel through the MQB barriers, while high energy electrons were reflected back by effective potential barrier to suppress the electron overflow from active to the cladding region. Multiple‐quantum wells (MQWs) are integrated at each side of MQB to minimize the overflow of tunneled electrons. A differential quantum efficiency change as small as 5% was achieved in the temperature range of 20–100 °C from MQB+MQW in active lasers.

Closed form dispersion expressions for a shielded microstrip line for millimetre wave applications

Abstract: Using the concept of virtual permittivity, a closed form dispersion model for a shielded microstrip line is proposed for 0.6/spl les/w/h/sub 1//spl les/10, h/sub 2//h/sub 1//spl ges/2, 1.05/spl les//spl epsiv//sub r1//spl les/20 and f.h/spl les/4.0 GHz/spl middot/cm. The model has RMS deviation within 1% as compared with that obtained using spectral domain analysis.

Study of fungi associated with bronchopulmonary disorders.

Abstract: Two hundred samples from sputum (160), bronchial secretions (35) and pleural aspirate (5) were analysed from patients of bronchopulmonary disorders. One hundred nine samples (54.5%) were positive for the fungi. Candida species (50%) were the predominant fungus isolated, followed by Aspergillus species (3.5%). Among various species of Candida, C. albicans accounted for 29.5% cases of bronchopulmonary disorders.

Hepatopancreatoduodenectomy in advanced carcinoma gall bladder.

Abstract: A patient with advanced carcinoma of the gall bladder was treated by hepatopancreatoduodenectomy. She had no postoperative complication, and is anicteric six months after surgery despite local recurrence.

Physical growth of rural pre-school children in Haryana.

Abstract: During 1987-89 field workers conducted a survey of 3731 children 0-5 years old living in rural Naraingarh subdivision of Ambala District in Haryana State India to examine their physical growth. 63% of the households had access to health care. 91% had access to a hand pump or tap water. Only 2% of the households had a latrine. Only 14.2% of the children weighed more than 90% of standards of the National Centre of Health Statistics (NCHS). 2.8% weighed less than 60% of the expected median weight for age. Boys were more likely to weigh more and be taller than girls. For example at age 60-72 months the mean weight of boys was 14.83 kg compared to 14.22 kg for girls and the mean height was 103 cm vs. 101.6 cm respectively. This study and other studies show that children in developing countries tend to have lower levels of physical growth than US children. NCHS standards are used since they represent the optimal levels of growth to be attained. They may include data on obese children however. Thus using the NCHS standards for Indias screening program for growth monitoring may be inappropriate. These norms can be revised to better reflect the Indian situation.

System Design of Integrated Optics Spectrum Analyser with Tilted Fresnel Lens

Abstract: Integrated optics spectrum analyser is the optical version of rf spectrum analyser with the capability of handling large amount of real time signal in a small, low power design. In this paper we determine the specifications and placement of the subsystems for a bandwidth of 400 MHz and resolution of 4 MHz at the centre frequency of 600 MHz. Computer simulation has been used to show that a tilted fourier transform fresnel lens has to be used to achieve low aberration over a wide band.