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Biomedical subjects

S Yadav

Publications and source records attributed to S Yadav.

At least 19 recordsLinked to original sources
PubMed2025

Optimising parent selection in plant breeding: comparing metaheuristic algorithms for genotype building.

Stacking desirable haplotypes across the genome to develop superior genotypes has been implemented in several crop species. A major challenge in Optimal Haplotype Selection is identifying a set of parents that collectively contain all desirable haplotypes, a complex combinatorial problem with countless possibilities. In this study, we evaluated the performance of metaheuristic search algorithms (MSAs)-genetic algorithm (GA), differential evolution (DE), particle swarm optimisation (PSO), and simulated annealing (SA) for optimising parent selection under two genotype building (GB) objectives: Optimal Haplotype Selection (OHS) and Optimal Population Value (OPV). Using a diverse wheat population of 583 lines genotyped for 29,972 SNPs, forming 7645 haplotype blocks and phenotyped for stripe rust scores, we assessed each algorithm's performance across fitness optimisation, convergence speed, and computational efficiency. GA consistently achieved high fitness and rapid convergence, while DE showed robustness but required longer runtime and careful tuning. PSO performed well under the OHS criterion but was less effective for OPV. SA, although computationally lighter, was less consistent in finding optimal solutions. Simulation over 100 breeding cycles showed that OHS outperformed both OPV and GEBV-based selection in long-term genetic gain and diversity retention. OHS maintained heterozygosity and additive variance, which are key for sustainable improvement, while GEBV selection led to early allele fixation. Our findings underscore the potential of GB strategies that prioritise the collective performance of parent sets rather than individual ranking to enhance selection outcomes in genomic-assisted breeding programmes.

Plant Breeding↗
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↗
PubMed1990

Circulating iso and auto antibodies to human spermatozoa in infertility.

Blood samples from 50 couples of unexplained primary infertility and 25 healthy fertile couples were tested for antispermatozoa antibodies (ASA) by gelatin agglutination test and sperm immobilising complement dependent cytotoxicity test. The incidence of sperm agglutinating and sperm immobilising antibodies was found to be 14 per cent and 10 per cent respectively in infertile couples. Agglutinating antibodies were detected in 18 per cent males and 16 per cent of females while cytotoxic antibodies were found in 14 per cent males and 10 per cent of females. Only 4 per cent of the normal fertile couples taken as a control group showed positive ASA, hence the difference in incidence of positive ASA between the infertile and fertile couples was found to be statistically significant. Also, the agglutination test was observed to be more sensitive than the cytotoxicity test.

Agglutination Tests↗
PubMed1989

Role of natural frequency of bone as a guide for detection of bone fracture healing.

The natural frequency of bone is studied in normal and fractured bones, in vitro as well as in vivo, by recording the outputs of microphone pick-ups, attached at proximal and distal ends to the bone defect. Natural frequency of bone is determined for an optimum output displayed on a cathode ray oscilloscope with respect to different stress wave frequencies. A comparative study of normal and fractured bone in vivo in 25 patients was made to diagnose the size of the fracture and its rate of healing. The natural frequency and intensity of sound in the injured bone was reduced while the output voltage increased with respect to the normal bone. The investigation reports a simple, reliable and rapid technique for the assessment of bone fracture.

Animals↗
PubMed1989

Captopril.

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Captopril↗
PubMed1989

Respiratory complication in tetanus.

Six hundred cases of tetanus were studied to find out incidence of respiratory complications and to evaluate factors predisposing such complications in tetanus. The incidence of complications was 41 per cent. Infants, patients of more than 40 years of age, smokers, cases with grossly contaminated injuries, short incubation period and short period of onset were more vulnerable. Patients with dysphagia, spasm, associated respiratory diseases and the patients in higher grades were also found to be more susceptible to respiratory complications.

Adolescent↗
PubMed1989

Propranolol.

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Arrhythmias, Cardiac↗