PubMed Health⌕ Search

Biomedical subjects

S Yadav

Publications and source records attributed to S Yadav.

At least 73 records · Page 4Linked to original sources
PubMed1993

Do umbilical vein catheterization and sepsis lead to portal vein thrombosis? A prospective, clinical, and sonographic evaluation.

Extrahepatic portal vein obstruction (EHPVO) affects 20-30% of all patients with portal hypertension in India. The etiopathogenesis of this disease is unknown. In retrospective studies, umbilical vein cannulation and sepsis have been alleged to cause portal thrombosis. This prospective study was undertaken to detect clinically and by serial sonography whether thrombosis and consequent obstruction of the splenoportal venous system develops after umbilical vein catheterization and sepsis. Forty-seven children who had undergone exchange transfusion for hyperbilirubinemia, belonging to two different age groups, were studied. Twenty-two new-borns (Group A) were studied within 4 weeks of birth and later at 3-month intervals until the age of 12 months and subsequently at 24 months. Another group of 25 children (Group B), 1- to 5-year-olds who had earlier undergone exchange transfusion and 15 healthy newborns (Group C) were also screened. In Group A, seven (29%) neonates had septicemia, and in five, the splenic vein could not be initially visualized. The splenic vein was not seen in five of the 15 newborns in Group A who had no umbilical sepsis. Twenty-one of the 22 neonates in Group A were followed-up, and the splenic vein was well visualized and found patent on subsequent ultrasound in all of them. In Group B, four (16%) children had umbilical sepsis. None of these or the other Group B children showed any thrombosis or obstruction of the splenoportal system. The portal vein and its branches and the splenic vein were visualized in all healthy (Group C) neonates.(ABSTRACT TRUNCATED AT 250 WORDS)

Catheterization, Peripheral↗
PubMed1993

Diagnostic value of maternal serum alpha fetoprotein for predicting pregnancy outcome in high risk pregnancies: an epidemiological perspective.

This study was conducted on high risk pregnancies, between 6-40 weeks of gestation, to evaluate the difference in maternal serum alphafetoprotein (MSAFP) levels in normal and abnormal pregnancies. It's predictive value for pregnancy outcome was calculated. Age and parity matched, normal pregnant women with normal pregnancy outcome were taken as controls. It was determined that the overall sensitivity (75.6%) and specificity (83.7%) was not very good for diagnostic purposes. On the contrary in patients with neural tube defects, congenital anomalies, early pregnancy complications leading to fetal death, still birth, neonatal deaths, Rh incompatibility and preterm deliveries the specificity was (96%-100%), due to very few false positives but sensitivity was comparatively low (75%-89%) due to many false negatives. As a result the predictive value of a negative test in these conditions was very high (80%-100%), though that of a positive test was comparatively low (60%-89%). This establishes a diagnostic value of MSAFP, especially in high risk pregnancies as opposed to its use as a screening test for all pregnancies. This is of special value for a poor country like India, where it is not possible to screen total pregnant population due to economic and logistic reasons.

Adolescent↗
PubMed1993

Acid phosphatase and lipid peroxidation in human cataractous lens epithelium.

The anterior lens epithelial cells undergo a variety of degenerative and proliferative changes during cataract formation. Acid phosphatase is primarily responsible for tissue regeneration and tissue repair. The lipid hydroperoxides that are obtained by lipid peroxidation of polysaturated or unsaturated fatty acids bring about deterioration of biological membranes at cellular and tissue levels. Acid phosphatase and lipid peroxidation activities were studied on the lens epithelial cells of nuclear cataract, posterior subcapsular cataract, mature cataract, and mixed cataract. Of these, mature cataractous lens epithelium showed maximum activity for acid phosphatase (516.83 moles of p-nitrophenol released/g lens epithelium) and maximum levels of lipid peroxidation (86.29 O.D./min/g lens epithelium). In contrast, mixed cataractous lens epithelium showed minimum activity of acid phosphatase (222.61 moles of p-nitrophenol released/g lens epithelium) and minimum levels of lipid peroxidation (54.23 O.D./min/g lens epithelium). From our study, we correlated the maximum activity of acid phosphatase in mature cataractous lens epithelium with the increased areas of superimposed cells associated with the formation of mature cataract. Likewise, the maximum levels of lipid peroxidation in mature cataractous lens epithelium was correlated with increased permeability of the plasma membrane. Conversely, the minimum levels of lipid peroxidation in mixed cataractous lens epithelium makes us presume that factors other than lipid peroxidation may also account for the formation of mixed type of cataract.

Acid Phosphatase↗
PubMed1993

Usefulness of immunoperoxidase test for serodiagnosis of genital chlamydial infections.

An immunoperoxidase test detecting Chlamydia trachomatis specific serum IgG and IgA antibodies, was carried out to determine its efficacy in establishing chlamydial etiology in 104 clinically diagnosed patients attending a major STD Clinic in Delhi. The patients consisted of 58 with nonspecific urethritis/cervicitis (NSU/NSC), 11 with pelvic inflammatory disease (PID), 23 with primary infertility in either male or female and 12 with lymphogranuloma venereum (LGV). IgG antibodies were tested at a dilution of 1:64 and 1:128 and IgA antibodies at 1:16. Although 27.7 per cent (5 of 18) of the controls had IgG antibodies (> or = 1:128), none had IgA, showing the IgA marker as 100 per cent specific. In 80.8 per cent of all the patients, active infection was detected, 81.0 per cent in NSU/NSC, 81.8 per cent in PID, 76.9 per cent in female infertility, 80 per cent in male infertility and 83.3 per cent in LGV patients. The immunoperoxidase test was found to be an extremely simple and rapid test especially suited for laboratories where facilities are limited.

Adolescent↗
PubMed1992

Determining stability of proteins from guanidinium chloride transition curves.

The guanidinium chloride (GdmCl) denaturation of RNAase A, lysozyme and metmyoglobin was investigated at several pH values by using absorbance measurements at 287, 300 and 409 nm respectively. From these measurements the free-energy change on denaturation, delta Gapp., was calculated, assuming a two-state mechanism, and values of delta Gapp. at zero concentration of the denaturant were measured. For each protein all delta Gapp. values were adjusted to pH 7.00 by using the appropriate relationship between delta Gapp. and pH. Dependence of the adjusted delta Gapp. value on GdmCl concentration increases for metmyoglobin and decreases for the other two proteins as the denaturant concentration decreases. It has been shown that these are expected results if the presence of the acid-denatured state during the GdmCl denaturation of proteins is considered.

Drug Stability↗
PubMed1992

Evolution of B-cell lymphoma from pseudolymphoma. A multidisciplinary approach using histology, immunohistochemistry, and Southern blot analysis.

Cutaneous B-cell lymphomas are rare neoplasms that can present as lesions involving solely the skin or develop in association with a systemic lymphoma. Histologically they are often difficult to differentiate from pseudolymphomas, and the use of immunohistochemistry may be necessary to correctly classify them. We report a study of multiple skin lesions in a patient who initially presented with multiple pseudolymphomas, apparently associated with an immune response to the dye of his tattoos. Over a period of 4 years his skin lesions evolved from histologically benign and immunologically polyclonal pseudolymphomas to a histologically malignant and immunologically monoclonal B-cell large cell lymphoma. Genotypic analysis with a probe for the heavy-chain immunoglobulin gene demonstrated the presence of clonal B-cell populations in all of the pseudolymphoma biopsy samples as well as in the subsequent lymphoma tissue samples, with a pattern of clonal bands suggestive of evolution of the B-cell clones. These findings suggest that the development of B-cell lymphoma in this patient was related to a persistent abnormal immune response to the chronic antigenic stimulus of the dye of the tattoo. The presence of clonal B-cell populations in pseudolymphoma by Southern blot analysis may be useful in predicting those patients who will subsequently develop overt lymphoma.

Blotting, Southern↗
PubMed1992

Cholesterol and lipid peroxidation in 3 beta-(2-diethylaminoethoxy)- androst-5-en-17-oneHCl (U18666A) induced cataractogenesis in rats.

Decrease in cholesterol was observed in precataractous, cataractous, advance nuclear cataractous and non-cataractous lenses when 3 beta-(2-diethylaminoethoxy)-androst-5-en-17- oneHCl (U18666A) was injected, sc, to rats. Significant increase in lipid peroxidation was observed before the onset of any apparent lenticular opacity in U18666A treated rats. The results suggest that decrease in cholesterol is capable of altering the structural integrity of lens fibers. However, 12.5% decrease in cholesterol and 5% increase in lipid peroxidation observed in non-cataractous lenses indicated that these changes are not sufficient for any apparent opacification.

Androstenes↗
PubMed1991

Lens epithelial cell density and histomorphological study in cataractous lenses.

Human epithelial cell density was determined from flat preparation of 195 cataractous lenses from 108 males and 87 females between 30 and 80 years of age. The mature cataracts had significantly lower cell counts than the other cataracts. Cell density was significantly higher in the females than in the males. Morphohistological study of the epithelia was focused on the following cataract types: (1) nuclear, (2) posterior subcapsular, (3) mature, (4) mixed, (5) hypermature, and (6) black. The major cataractous changes in all types involved vacuolization of the cytoplasm. The mature types of cataractous epithelia showed 56% superimposed cells; the epithelia in nuclear, posterior subcapsular, and black cataracts showed between 6% and 16%. In the hypermature cataracts, four of five tissues analyzed showed superimposed cells. The superimposed areas are probably the source of increased and altered cell activity. We propose that the metaplastic processes leading to posterior capsular opacification originate from these areas. The majority of nuclear and black cataracts were almost similar to the normal human lens epithelium with more or less uniform distribution of cells. Nucleus shrinkage (5 microns) was more evident in nuclear cataracts; in subcapsular cataracts most of the nuclei were large (average 9 microns diameter). Variation in morphological changes like vacuolization of cytoplasm and nuclei, pyknotic nuclei, and superimposed cells was more evident in the mixed type of cataracts.

Adult↗
PubMed1991

Selenium and diabetes in the tropics.

We have examined the possibility that selenium deficiency may underlie one or more of the following peculiarities of chronic pancreatitis in tropical as compared to temperate zones: much higher prevalence, propensity for pancreatic calculi, and high frequency of diabetes. Selenium was measured by graphite furnace atomic absorption spectrometry in sera from 20 healthy volunteers, 36 patients with chronic pancreatitis (calcific 35, diabetic 32), and 23 patients with primary forms of diabetes, from Madras, South India; results were compared with data from 41 controls and 37 patients with chronic pancreatitis (calcific 13, diabetes 8) from Manchester, North West, England. We conclude that (a) bioavailability of selenium is equally high in each geographic area; (b) decrement in serum selenium (p less than 0.001) is of a similar order in Manchester and Madras patients, which denies a connection with calculi formation or pancreatic exocrine failure (since the incidence of these two problems was substantially higher in the Madras series); and (c) selenium levels do not account for accelerated course to diabetes in tropical chronic pancreatitis.

Adolescent↗
PubMed1991

Puerperal tetanus.

Fifty cases of puerperal tetanus were studied. It constituted 6.66% of total cases of tetanus with overall mortality of 52% which was higher in cases with incubation period of 14 days or less, period of onset 48 hours or less, higher grades, cases with temperature more than 37.7 degrees C and patients with respiratory complications. Significantly higher mortality rate after 48 hours signifies the need of effective local control of infection to improve prognosis. Prevention, early detection and prompt treatment of respiratory complications which is the main cause of death may further reduce mortality rate in these patients.

Female↗
PubMed1990

Identification of a region of UDP-galactose:N-acetylglucosamine beta 4-galactosyltransferase involved in UDP-galactose binding by differential labeling.

The location of regions in the primary structure of UDP-galactose:N-acetylglucosamine beta 4-galactosyl-transferase (GT) that are involved in binding UDP-galactose has been investigated by differential chemical modification with two different reagents in the presence and absence of UDP-galactose. Treatment with periodate-cleaved UDP and NaCNBH3 resulted in a loss of 80% of GT activity, which was largely prevented by UDP-galactose. Stoichiometry of labeling and peptide maps of the modified enzyme samples indicated partial labeling at many sites. A major site of reaction in the absence of UDP-galactose that was essentially unmodified in its presence was found to correspond to Lys341 in the cDNA sequence of GT. As a second approach, the reactivities of the amino groups of GT were compared in the presence and absence of saturating levels of UDP-galactose by trace acetylation with [3H]acetic anhydride. UDP-galactose binding was found to perturb the reactivities of a number of lysines in the C-terminal region of GT, the most pronounced effect being a reduction in the reactivity of Lys351. The two procedures thus identified a region between residues 341 and 351 as being associated with UDP-galactose binding. This region overlaps a small section in the sequence of GT that was previously noted to be similar to part of bovine alpha-1,3-galactosyltransferase (Joziasse, D. H., Shaper, J. H., Van den Eijnden, D. H., Van Tunen, A. J., and Shaper, N. L. (1989) J. Biol. Chem. 264, 14290-14297). Sequence comparisons indicate that extended regions at the C terminus of each enzyme encompassing this area may represent homologous UDP-galactose-binding domains.

Amino Acid Sequence↗
PubMed1990

A stress wave propagation technique for bone repair study.

The diagnosis of bone fracture and its rate of healing still remains a problem among orthopedic surgeons. An acoustic technique based on stress-wave propagation is developed. The technique is used on laboratory experimental in vitro bones, as well as on in vivo (human) bones, to diagnose a fracture. The rate of healing of the fracture is also studied. The technique developed is quick, economical, reliable, portable, and safe for both the patient and the operator.

Animals↗
PubMed1990

Measurement of ultrasonic velocity and attenuation in bone tumors, in vitro.

Ultrasonic velocity and attenuation are determined in different types of bone tumors by using a double-probe-through-transmission ultrasonic technique. The average values of propagation velocity in different types of tumors are found as 2106, 2304, 2677.5, and 3586 m/s with 1.49%, 1.04%, and 0.74% standard deviation in Giant Cell, Lymphoma, Chondro Sarcoma, and Osteogenic Sarcoma, respectively. Absorption coefficient of ultrasound is found to be minimum as 19.7 dB/cm with 0.002% standard deviation in Lymphoma, and high in Osteochondroma and not measurable with the present setup. A direct technique for the diagnosis and differentiation of various types of tumors can be developed by standardization of the data.

Bone Neoplasms↗