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Biomedical subjects

A K Sharma

Publications and source records attributed to A K Sharma.

At least 415 records · Page 23Linked to original sources
PubMed1983

Monocyte-derived soluble suppressor factor(s) in patients with lepromatous leprosy.

Peripheral blood monocytes from polar lepromatous leprosy (LL) patients were unable to support Mycobacterium leprae-induced in vitro lymphoproliferation of HLA-D-matched T cells from tuberculoid leprosy subjects, whereas those from responder individuals were able to do so. Monocyte-rich adherent cells from untreated LL patients released de novo soluble factors which inhibited antigen-induced lymphoproliferation to a greater extent and mitogenic responses to a lesser extent. Suppressive activity varied in different LL patients. However, the degree of suppression was similar in soluble factors obtained de novo and after treatment of adherent cells with heat-killed and freshly extracted, cryopreserved M. leprae. Treated patients showed less inhibition with de novo released soluble factors (27 +/- 7.7%) as compared to parallel soluble factors obtained after antigen treatment (44 +/- 4.8%) or with de novo soluble factors from untreated LL patients (62 +/- 14.2%). Similar supernatants from tuberculoid individuals showed no or insignificant effects on antigen-induced lymphoproliferation. The suppressive activity of LL soluble factors was produced for up to 72 h, was heat stable at 56 degrees C for 30 min, was indomethacin resistant, and resided in the greater than 25,000 molecular weight fraction.

Blood Proteins↗
PubMed1983

The natural history of acute painful neuropathy in diabetes mellitus.

Observations have been made on nine cases of painful diabetic neuropathy of acute onset. All cases were male and all were associated with and preceded by precipitous and severe weight loss. The pain was of a continuous burning quality and experienced mainly in the legs, especially distally. Contact discomfort of the skin was often a troublesome feature, but sensory loss was mild or absent, and reflex loss or depression not invariable. There were no accompanying motor signs. Depression and impotence were constant features. The weight loss responded to adequate control of the diabetes with insulin and was followed by improvement in the neuropathy. The severe manifestations subsided in all cases within 10 months, and in most cases within 6 months, and later resolved completely in all except one. No recurrences were observed after follow-up periods of up to 6 years. Abnormalities of nerve conduction were mild or even lacking. Sural nerve biopsies from three cases taken in the acute stage showed evidence of active degeneration of myelinated nerve fibres of all diameters and also degeneration of unmyelinated axons. There was a mild degree of demyelination. It is concluded that acute painful diabetic neuropathy is a distinct syndrome, occurring in insulin or noninsulin dependent patients of any duration, and unrelated to other diabetic complications. It is separable from other types of painful diabetic sensory polyneuropathy that have been described.

Acute Disease↗
PubMed1983

Peripheral nerve abnormalities in the diabetic mutant mouse.

Observations were made on the genetically diabetic C57BL/Ks (db/db) mouse. Morphometric observations were performed on the tibial nerve at 6, 9, and 15 mo and compared with those from nondiabetic (m/m) controls. Myelinated fiber size was less in the diabetic animals at all stages and affected cross-sectional axon area and myelin thickness equally. Unmyelinated axons were unaffected. The index of circularity of myelinated axons did not differ between diabetic and control animals. No definite absolute reduction in fiber size occurred and degenerative changes, which were slight, were equally frequent in the diabetic and control nerves. Axonal glycogenosomes, polyglucosan particles, and Schwann cell/axon networks, and Schwann cell Reich granules increased with age in both groups, but only glycogenosomes were consistently more numerous in the diabetic animals. Counts of membrane associated particles in both P and E faces revealed that these were reduced in number in the diabetic animals in myelin and in axolemma of unmyelinated axons, but not in the axolemma of myelinated fibers. Growth in tibial length was also reduced in the diabetic animals and this suggested that the reduced fiber diameter probably represented a maturational deficit. The absence of a selective reduction in axonal size did not favor a primary axonopathy as the cause.

Animals↗
PubMed1983

Climatological and genetic effects on milk composition and yield.

Results confirm most other research on milk composition and yield. All responses were affected by climate, some considerably more than others, if percent of error variance is the criterion. Jersey yields were less sensitive to climate than were Holstein, but Jersey milk composition appeared more sensitive. Somatic cell count (REF), a measure of mastitis, was affected by climate but less than all other variables except protein/fat and LM%. Needed are estimates of interactions between climatic effects and response surface models to quantify possible improvement in performance following environmental modification. Genetic correlations between milk yield and REF and chloride % suggest that single trait selection for milk yield might increase incidence of mastitis although phenotypic correlations indicate that high yields and absence of mastitis are correlated.

Animals↗
PubMed1983

T cell subsets in leprosy lesions: in situ characterization using monoclonal antibodies.

Cryostat sections of dermal lesions from 30 untreated leprosy patients were studied by indirect immunofluorescence using monoclonal antibodies defining T cell subsets and Ia like antigens. Most lymphocytes in leprosy lesions were positive for OKT3 and Ia like antigens indicating thereby the presence of activated T cells. Maximal numbers of these cells were seen in localized paucibacillary tuberculoid leprosy lesions in close association with epithelioid cells. A decline in their numbers was observed over the leprosy spectrum with a marked reduction in disseminated, multi-bacillary, lepromatous leprosy where only scattered OKT3+ cells were visualized. OKT4 and OKT8 positive cells defining T cell subsets, were frequently found within the OKT3+ lymphocytes throughout the leprosy spectrum. The ratio of OKT4+/OKT8+ cells ranged from 1.2 to 5.0 in tuberculoid and from 0.2 to 1.0 in lepromatous lesions. Macrophages in the granulomas stained intensely with anti-Ia antisera. Ia like antigens were expressed to the same degree on macrophages with or without intracellular acid fast bacilli.

Antibodies, Monoclonal↗
PubMed1982

Age-at-onset of leprosy. (An analytic data from Northern India).

Very little information is available from Northern India about various intriguing facets of epidemiology of leprosy. Age-at-onset is a very important aspect of the epidemiology of the disease process. In the present study an analytic data of the patients from Northern India is presented. The mean age-at-onset of leprosy in males was 31.49 years and in female 29.43 years. The mean age-at-onset for N, N ? L and L types was 30.14, 30.12 and 34.13 years respectively. The data compared well with those of earlier series.

Adult↗
PubMed1981

The adhesion of glow--discharge polymers, Silastic and Parylene to implantable platinum electrodes: results of tensile pull tests after exposure to isotonic sodium chloride.

Thin organic coatings commonly are used for insulating microelectrodes and electronic packages designed for implant applications. The adherence of these coatings to the underlying substrates is a key parameter in their selection for various devices. Instron pull tests were performed on glow-discharge polymerized monomers, Parylene-N, medical-grade Silastic and various epoxies. The application of a thin coating of glow-discharge polymerized methane under a thicker Parylene-N coating improved the adhesion of the latter to the underlying substrate in isotonic sodium chloride solution and during accelerated testing conditions done by boiling.

Adhesiveness↗
PubMed1981

An interphase model for mitotic chromosome organization in eukaryota.

A model for the spatial relationship of the arrangement of the chromosomes in the nucleus in eukaryota is presented. Evidence is derived from light and electron microscopic studies, application of autoradiographic and banding techniques; on the organization, structure and behaviour of chromosomes during interphase and other stages of cell cycle. This model visualizes the entire chromosomal DNA as a single uninemic multirepliconic continuum where the chromosomes with their centromeres and telomeres have a predetermined arrangement among themselves as well as in relation to the nucleolus and nuclear membrane. This orderly arrangement is presumably maintained through interchromosomal connections. The impact of this model on the interpretation of various cytogenetic phenomena is discussed.

Animals↗
PubMed1981

Nerve conduction velocity in experimental diabetes in the rat and rabbit.

Tibial motor nerve conduction velocity was measured in rats, before and two months after the induction of diabetes with streptozotocin. A second group of diabetic animals was also administered 1% dietary myoinositol supplements. An analysis of variance was performed on these data. Myoinositol supplements had no effect whatsoever. The period of diabetes had a statistically significant and quantitatively marginal effect (a decrease of 2.2 m s-1) on conduction velocity. This is considerably less than in previous reports. The reasons for this are discussed. Tibial motor nerve conduction velocity was also measured in a group of alloxan-diabetic rabbits two months after the induction of diabetes and in an age-matched control group. Conduction velocity was again slightly but significantly less in the diabetic animals.

Animals↗
PubMed1981

Effect of spray and evaporative cooling on certain galactopoietic responses in buffaloes (Bubalus bubalis).

Nine normal lactating Murrah buffaloes from Punjab Agricultural University Dairy herd were used to assess the effect of spray and evaporative cooling on certain galactopoietic responses in buffaloes in three equal groups of control (Group I), showers (Group II) and evaporative cooling (Group III). At 10.30, 12.30, 14.30 and 16.30 h daily the animals in Group II were given showers for fifteen minutes while the animals of Group III were kept on evaporative cooling system from 07.00 to 21.00 h daily. All the animals of Groups I, II and III were given showers by splashing water on their bodies with buckets once a day as a general routine being practised in the farm. Physical parameters included were dry bulb temperature, wet bulb temperature, maximum and minimum temperature, light intensity, % R. H., total day length and cooling power of air. The various galactopoietic responses recorded were the let down time, the milking time, the milk yield, the average flow rate, the fat and lactose percentages. The results of this study revealed that the showers amd the evaporative cooling were responsible for increasing the galactopoietic responses, i. e. the milk yield, the milking time, the the average flow rate and decreasing the let down time in both the periods. This may be attributed to the added comfort to such animals.

Animals↗
PubMed1980

XY gonadal dysgenesis in a heifer.

The anatomical and histological features of the genital tract of a six-year-old Haryana heifer, which had failed to show oestrus, are described. The heifer had a 60 XY karyotype in the leucocyte culture. The external genital organs were absent and a small opening at the ventral perineal border acted as the external urogenital opening. The ovaries were completely hypoplastic and a uterus didelphys opened into a single cervix. No male sex organs or their rudiment were observed.

Animals↗
PubMed1980

Changes with age in the peripheral nerves of the rat. An ultrastructural study.

Ultrastructural observations have been made on the tibial and plantar nerves of Wistar rats aged 18-24 months. Changes indicative of segmental demyelination and remyelination and axonal degeneration and regeneration were prominent in the plantar nerves. Both in the plantar and tibial nerves, but particularly in the former, axonal abnormalities were frequent. These included the occurrence of multiple intra-axonal vacuoles containing glycogen and polyglucosan bodies. Axonal sequestration by adaxonal Schwann cell processes was also increased. The Schwann cell cytoplasm in relation to this activity contained bundles of filaments with the ultrastructural features of Hirano bodies. The changes in the plantar nerves probably indicate a pressure neuropathy, but the possibility of a superimposed distal axonal degeneration related to aging cannot be excluded on the present evidence. Such changes must be taken into consideration in experimental studies performed on rats of this age.

Aging↗
PubMed1980

Axoplasmic transport in vagal afferent fibres in normal and alloxan-diabetic rabbits.

Fast and slow components of anterograde axoplasmic transport have been studied in the sensory fibres of the vagus nerve of alloxan-diabetic rabbits and age-matched controls by incorporation of tritiated leucine into nodose ganglion cells. The diabetic rabbits were maintained for 2 months with blood glucose levels in the range 20--40 mmol/l. They showed growth retardation and one third developed cataracts. No alteration of either fast or slow axoplasmic transport was detected in the diabetic animals. These results are discussed in the light of the present understanding of the role of axoplasmic transport, of the findings in other axoplasmic transport studies, and of other data available on the pathogenesis of human and experimental diabetic neuropathy.

Animals↗
PubMed1980

Age changes in the tibial and plantar nerves of the rat.

Observations have been made on the changes in the myelinated fibres of the rat tibial and plantar nerves between 2 and 24 months of age. There is an initial rapid increase in fibre diameter followed by a later more gradual increase, which ceases after approximately 9 months of age in the tibial nerve but which continues for longer in the medial plantar nerve. The fibre size distribution remains substantially unimodal throughout. In both nerves maximal and average fibre diameter become reduced by 24 months. Total fibre number shows considerable variability between animals, but no definite systematic alteration with age is detectable. Teased fibre preparations demonstrate a low level of abnormality in the tibial nerve until after 18 months of age, but by 24 months approximately 30% of fibres display abnormalities. Although both paranodal and segmental demyelination and remyelination, and axonal degeneration and regeneration occur, the latter type of change predominates. By contrast, in the lateral plantar nerve paranodal and segmental demyelination become detectable to a significant extent from 6 months of age. Axonal degeneration and regeneration also become evident after 15 months, and by 24 months of age 55% of fibres show abnormalities. The possible explanation of these changes is discussed, as is their relevance to the frequent use of the tibial nerve for studies on experimental neuropathies.

Aging↗