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Biomedical subjects

V Kumar

Publications and source records attributed to V Kumar.

At least 37 records · Page 2Linked to original sources
PubMed1992

Alzheimer Disease Assessment Scale: a subtest analysis.

The Alzheimer Disease Assessment Scale (ADAS) was administered to 61 Alzheimer patients, 52 elderly controls, and 80 controls between age 7 and 54 years. The Alzheimer group was categorized into different severity levels of dementia based on MMSE scores: very mild (> or = 24), mild (> or = 20), moderate (10-19), and severe (0-9). All 11 ADAS Cognitive subtest scores for the mild, moderate, and severe dementia groups were statistically worse than the elderly control group. This was also the case for the very mild group, except for Naming, Commands, Constructional Praxis, and Ideational Praxis. In terms of magnitude of effect, memory and spontaneous language items were the earliest indicators on the ADAS, while praxis, commands, and naming items were only sensitive later in the course of the disorder. The best single indicators of progression throughout the severity continuum of dementia (i.e., from normal to severe) were the Orientation subtest, the ADAS Cognitive score, and the ADAS Total score. The ADAS Noncognitive subtests generally did not show the progression with increasing dementia that was evident on the ADAS Cognitive subtest. Differences in educational level had no statistically significant effects on any of the ADAS subtest scores, and age differences were few and small in magnitude. The differential rate of decline of the various ADAS subtests appears to reflect both the changing pattern of cognitive impairments as a function of severity of DAT and also to some extent the psychometric limitations of some of the subtests.

Aged↗
PubMed1992

Differentiation of bullous pemphigoid from epidermolysis bullosa acquisita on frozen skin biopsies.

Patients with bullous pemphigoid and epidermolysis bullosa acquisita may have similar clinical, histologic, and routine immunohistologic features. These two diseases can be distinguished by routine diagnostic studies either on a patient's serum tested by indirect immunofluorescence on salt-split normal skin or by obtaining a fresh perilesional skin biopsy, inducing a split at the lamina lucida, and testing for the site of IgG deposition by direct immunofluorescence. Often the serum studies are negative, while direct immunofluorescent studies yield the characteristic linear IgG staining of the basement membrane zone. To eliminate the need for a repeat biopsy to make a laboratory differential diagnosis, we studied the efficacy of salt-splitting perilesional skin biopsies that had been previously submitted and frozen for routine direct immunofluorescent studies. The biopsies were thawed, salt-split, and processed for direct immunofluorescence. Three epidermolysis bullosa acquisita biopsies and seven bullous pemphigoid biopsies examined demonstrated IgG staining at sites consistent with their respective diagnoses. The IgG appeared in the dermal side of the split biopsies in epidermolysis bullosa acquisita and predominantly, or exclusively, in the epidermal side in bullous pemphigoid. Thus the direct immunofluorescent study of previously frozen and subsequently salt-split skin biopsies may be used for the differential diagnosis of bullous pemphigoid from epidermolysis bullosa acquisita. In most cases, it may eliminate the need for a repeat biopsy.

Basement Membrane↗
PubMed1992

A distinct stratum corneum antigen in psoriasis and its reactions with stratum corneum autoantibodies.

Stratum corneum antibodies are ubiquitous and can be detected by various immunological methods. Of these, the ones detected by hemagglutination undergo changes in antibody titers and have been implicated in psoriasis. The purpose of our study was to examine if differences exist in the activities of the antigens isolated from psoriatic scales in comparison to normal callus. Stratum corneum antigens were prepared by trypsin-phenol-water extraction. The water phase, which contains the stratum corneum antigen, was used to sensitize the red blood cells in the hemagglutination assay. The antibody activity in human sera was determined before and after absorption with antigens isolated from callus, psoriatic scales, and cell envelopes. We found notable differences in the antigens obtained from callus and psoriatic scales. These include higher antibody titers to the antigens of the scales, the presence of unique antigenic determinants on psoriatic scales and the localization of the antigen on cell envelopes. These immunological differences were corroborated by the marked biochemical differences of certain amino acids, most notably glycine and proline, and these differences were unique to psoriatic scales as they were not shared with other hyperproliferative disorders.

Amino Acids↗
PubMed1992

Murine natural killer cells and marrow graft rejection.

Rejection of bone marrow transplants in lethally irradiated mice differs from rejection of solid tissue grafts in several respects. The genetic laws that govern rejection of solid tissue grafts often fail with hemopoietic grafts. For example, F1 hybrids between two H-2 disparate strains of mice often reject parental bone marrow cells (BMC), and conversely, marrow cells of F1 hybrids (H-2 heterozygous) are usually not rejected by either parent or an unrelated allogeneic recipient. Thus, unlike the classical MHC antigens, the hemopoietic histocompatibility (Hh) antigens relevant in marrow graft rejection are inherited in a recessive pattern. The major Hh (Hh-1) locus maps within the mouse H-2 complex between the H-2S and H-2D regions, and it can therefore be dissociated from the class-I MHC genes. Nevertheless, it is possible that class-I MHC antigens play a role in the formation or expression of Hh-1 antigens. Three models that explain the possible relationship between class-I MHC and Hh-1 genes and the noncodominant pattern of inheritance of Hh antigens are presented. The effector cells responsible for resisting BMC grafts are different from those responsible for rejection of solid tissue grafts. Three cell types, natural killer cells (CD3-, NK1.1+), cytotoxic T cells (CD3+, CD8+), and T cells with natural killer cell markers (CD3+, NK1.1+) have been implicated in the rejection of BMC grafts. Involvement of these cell types is reviewed and the relative roles played by each are discussed. Evidence supporting the existence of Hh-1 specific subsets of NK cells is presented.

Animals↗
PubMed1992

Quantitative studies of immunofluorescent staining. VII. Quantitative reference standard slide for standardization of fluorescence microscopes.

We evaluated a quantitative reference standard (QRS) slide with 10-microns beads with different concentrations of Coulter Electronics green dye No. 1. Microfluorospectrophotometric readings of the QRS slides provided quantitative comparisons between the sensitivity of the different fluorescence microscopes. The visual comparisons between beads with a range of intensities of fluorescence of Coulter Electronics green dye No. 1 indicated that the end points vary with different optical systems as do the end points in standard indirect immunofluorescent titrations. Fluorescent emission wavelength of QRS slide beads gave the same peak as fluorescein-labeled beads; both differed from the peak of orange beads of an 'Optical Standard' slide. Since shelf life studies show no changes in fluorescence intensity of beads over a period of 27 months or longer, QRS slide beads can afford a device for standardization of fluorescence microscopes used for immunofluorescent tests.

Animals↗
PubMed1992

A preliminary study of correlation of immuno-histological and ultrastructural characteristics of neural granuloma in leprosy patients.

With an aim to better understand the pathogenesis of nerve damage in leprosy, peripheral nerve biopsies from six untreated leprosy cases (3 BT/TT and 3 BL/LL) were studied by electronmicroscopy and immuno-histology. In addition to routine histopathology for diagnosis, infiltrating cells of granuloma were characterized after preparation of single cell suspension. The lymphocytes in the lesion were characterized by E and EAC rosetting and macrophage phagocytic system (MPS) cells were studied using histochemical markers like esterase and peroxidase. The results indicate that the lymphocyte content was significantly greater in tuberculoid neural granuloma compared to lepromatous nerves and these formed rosettes with sheep erythrocytes (E) and expressed HLA-DR antigen suggesting that they are activated T cells. Infiltrating macrophages in both the tuberculoid and lepromatous neural granuloma were esterase positive, peroxidase negative and did not form rosettes with sheep erythrocytes or EAC. Ultrathin sections of tuberculoid granuloma showed lymphocytes clearly associated to epithelioid macrophages having well developed Golgi apparatus and rough endoplasmic reticulum. Correlation of these immunological and ultrastructural characters suggests that hypersensitivity mechanisms are possibly responsible for nerve damage in tuberculoid leprosy. Ultrastructural examination of lepromatous nerves, on the other hand, showed the predominance of macrophages with large nucleus, heavily bacillated Schwann cells, and a few lymphocytes. The correlation of immuno-histological and ultrastructural characters indicates that the mechanism(s) of nerve damage in lepromatous leprosy are basically different wherein hypersensitivity appears to play a very limited role.

Academies and Institutes↗
PubMed1992

Alzheimer disease assessment scale: useful for both early detection and staging of dementia of the Alzheimer type.

The Alzheimer Disease Assessment Scale (ADAS) was administered to 61 patients with dementia of the Alzheimer type (DAT) and 52 elderly controls. The DAT group was subdivided into different severity levels of dementia based on scores from the Mini-Mental State Exam: very mild (greater than or equal to 24), mild (20 to 23), moderate (10 to 19), and severe (0 to 9). The mean scores on the ADAS Cognitive subscale for the four levels of dementia (very mild = 23.1 +/- 7.7, mild = 22.9 +/- 8.9, moderate = 38.6 +/- 9.8, severe = 54.8 +/- 7.6) were statistically different from one another (p less than 0.0001, except very mild vs. mild) and were significantly worse than the scores of the elderly control group (5.5 +/- 2.7, p less than 0.0001, ANOVA). Furthermore, the ADAS Cognitive subscale was highly effective in discriminating individual Alzheimer patients from elderly controls. The ADAS Cognitive score correctly classified 100% of the very mild group, 91% of the entire mild group, and 100% of the moderate and severe groups when a cutoff score of 2 SDs above the control group mean was used. Age and education had only minimal effects on the ADAS Cognitive score. The ADAS is a valuable screening test that only takes 30 min to administer and has utility in both early detection and staging of DAT.

Adolescent↗
PubMed1992

Hematologic relapse of chronic myelogenous leukemia following allogeneic bone marrow transplantation: apparent graft-versus-leukemia effect following abrupt discontinuation of immunosuppression.

Two patients with hematologic relapse of chronic myelogenous leukemia (CML) following allogeneic BMT were treated by abrupt discontinuation of cyclosporine. Both patients rapidly attained complete hematologic and cytogenetic remission and remain free of disease with long follow-up. In the first patient, disappearance of CML was associated with the development of graft-versus-host disease (GVHD). In the second patient GVHD did not develop until after clearing of disease had been documented by cytogenetic analysis. Laboratory studies in the second patient disclosed the presence of lytic activity against both K562 and autologous CML cells that enhanced with IL2. Correlation with serial immunophenotyping data from this patient suggests that the effector for this graft-versus-leukemia (GVL) reaction could have been a T lymphocyte. Abrupt discontinuation of post-transplant immunosuppression with cyclosporine may represent a therapeutic approach to CML which has recurred following BMT. Moreover, investigation of this clinical phenomenon in subsequent cases may permit direct study of the cellular mechanisms involved in the GVL effect.

Adult↗
PubMed1992

Serologic markers of gluten-sensitive enteropathy in bullous diseases.

BACKGROUND AND DESIGN: Dermatitis herpetiformis (DH) is characterized immunologically by the presence of IgA immune deposits in the skin and by the presence of various serum antibodies. Of these, antibodies to gliadin, reticulin, and endomysium have been found to be significant. There are, however, conflicting reports as to the exact specificity and sensitivity of these serologic markers in diagnosing DH. We examined the disease specificity of these three antibody markers in 14 patients with DH, in 98 patients with pemphigus and pemphigoid, and in 26 normal subjects. Reticulin and endomysium antibodies were detected by indirect immunofluorescence and gliadin antibodies by means of the enzyme-linked immunosorbent assay method. RESULTS: Among the various bullous diseases, endomysial and reticulin antibodies were found to be disease specific for DH. Endomysial antibodies occurred in twice the number of DH patients (72%) compared with the occurrence of reticulin antibodies (36%). Antigliadin antibodies were detected in two thirds of DH patients and were not disease specific since increased frequencies of these antibodies were also detected in patients with pemphigus and pemphigoid. CONCLUSION: These studies support the earlier findings of the high degree of specificity of endomysial antibodies for DH and, thus, help to differentiate DH from other bullous disorders.

Antibodies↗
PubMed1992

[Immunodiagnosis of Taenia saginata cysticercosis].

Many different serological tests have been investigated in order to replace the current "knife and eye" method at the slaughterhouse, which detects only a small fraction of the cattle infected with cysticercosis. Among the assays for the detection of antibodies against the cysticerci of Taenia saginata, the ELISA is certainly the most sensitive, although it is unable to detect lightly infected animals. Consequently it only allows a group diagnosis in naturally infected cattle. The use of purified antigens of T. saginata, T. crassiceps and T. hydatigena did not improve significantly the reliability of these antibody detection tests. Recently monoclonal antibodies have been developed against surface or excretory- and secretory antigens of T. saginata metacestodes, allowing the detection of circulating antigens in the serum of infected cattle. Furthermore these monoclonal antibodies can distinguish animals carrying living, infectious cysticerci from those harbouring only dead cysticerci. Research is currently going on in order to improve the sensitivity of this antigen detection test, so that it can replace the current unreliable meat inspection methods in the slaughterhouse.

Animals↗
PubMed1992

Termination of photorefractoriness in the brahminy myna, Sturnus pagodarum: role of photoperiods and gonadal hormones.

In brahminy myna a photosensitive species, long days caused full gonadal development followed by rapid regression, whereas short days inhibited these responses. Experiments were performed to investigate the effects of duration of photoperiod and gonadal hormones on the recovery of photosensitivity to long photoperiods in male birds. Groups of photorefractory birds were subjected to 8-, 9- or 11-hr daily photoperiods for 45 (6.5 weeks) or 63 (9 weeks) days and then transferred to 15 h daily photoperiods for 60 days to check for the regaining of photoresponsivity. A control group was held under 15L:9D throughout the period of study. Another experiment included three groups of photorefractory males, which were maintained on 9L:15D for 9 weeks and administered with, birth-1day-1 alternately for first 30 days olive oil or different doses (10 or 100 micrograms) of testosterone propionate (TP)/bird/day alternately for first 30 days, and then transferred to 15L:9D for another 30 days to test the recovery of photosensitivity. The results indicated that (i) a period of exposure to short daylengths is required to dissipate photorefractoriness, (ii) termination of photorefractoriness is dependent on the length and duration of photoperiods and (iii) TP inhibits the recovery of photosensitivity in a dose dependent manner.

Animals↗
PubMed1992

Susceptibility of south Indian strains of Mycobacterium tuberculosis to tuberactinomycin.

A total of 114 strains of Mycobacterium tuberculosis isolated from sputum samples of 114 patients of pulmonary tuberculosis in south India, were coded and tested for their in vitro susceptibility to tuberactinomycin (Tum) incorporated in Lowenstein-Jensen (LJ) medium. Of these strains, 95 (83.3%) and 15 (13.2%) were susceptible to Tum at 25 and 50 mg/l respectively. Only 4 (3.5%) strains were inhibited at 100 mg/l or more. Of the 37 drug sensitive strains, 2 (5.4%) were not susceptible to Tum at 25 mg/l compared to 17 (22.1%) of 77 strains-resistant to one or more of antituberculosis drugs (P less than 0.02). The drug susceptibility pattern of the strains revealed that there was no significant association of resistance between Tum and streptomycin or rifampicin or ethambutol or ethionamide or isoniazid. However, 15 (53.6%) of 28 kanamycin (K) resistant strains were not susceptible to Tum at 25 mg/l. This cross resistance between Tum and K was further studied in 24 and 15 K sensitive and resistant strains respectively, by correlating their proportion resistance at 16 mg/l and it was found to have a significant positive correlation (r = 0.55; P less than 0.01).

Drug Resistance, Microbial↗
PubMed1992

Role of the indigenous drug saptamrita lauha in hemorrhagic retinopathies.

A clinical study was done on 48 eyes to assess the role of an indigenous drug, Saptamrita Lauha, in the absorption of hemorrhages and prevention of their recurrence in retinopathic eyes. Rapid absorption of retinal hemorrhages was observed in both treated groups: diabetic and hypertensive (mean durations, 16 days and 17.83 days, respectively). In three eyes, the hemorrhage cleared completely; partial clearance was observed in the rest of the eyes. Recurrence of a hemorrhagic episode was less in treated eyes (25% in each group) compared with control eyes (60% in diabetic and 50% in hypertensive patients). This study suggests that Saptamrita Lauha may hasten the process of retinal hemorrhage absorption and prevent its recurrence. The beneficial effect could be attributed to the flavanoid-like properties of one of the ingredients of this natural product.

Adult↗
PubMed1992

Effect of certain toxicants on gonadotropin-induced ovarian non-esterified cholesterol depletion and steroidogenic enzyme stimulation of the common carp Cyprinus carpio in vitro.

Isolated ovarian tissues from the common carp, Cyprinus carpio were incubated in vitro to obtain a discrete effect of four common toxicants of industrial origin, namely phenol, sulfide, mercuric chloride and cadmium chloride, on gonadotropin-induced alteration of nonesterified and esterified cholesterol and steroidogenic enzymes, delta 5-3 beta-HSD and 17 beta-HSD activity. Stage II ovarian tissue containing 30-40% mature oocytes were shown to be most responsive to gonadotropins in depleting only nonesterified cholesterol moiety and stimulating the activity of both. Safe doses of above mentioned toxicants when added separately to stage II ovarian tissue with oLH (1 microgram/incubation) gonadotropin-induced depletion of nonesterified cholesterol and gonadotropin-induced stimulation of the activity of both enzymes was significantly inhibited. Esterified cholesterol remained almost unaltered. Findings clearly indicate the impairment of gonadotropin induced fish ovarian steroidogenesis by the four toxicants separately.

17-Hydroxysteroid Dehydrogenases↗
PubMed1991

T cell receptor gamma and delta gene rearrangements in scid thymocytes. Similarity to those in normal thymocytes.

The nature of TCR gamma and delta gene rearrangements in 4- to 6-week-old scid thymocytes was examined by using the polymerase chain reaction technique, cloning, and DNA sequencing. Analysis of 78 sequences indicates that TCR gamma and delta gene rearrangements in scid mice generally resemble those in thymocytes from normal young adult mice. V gamma 1, V gamma 2, and V gamma 5 rearrangements are heterogeneous, with extensive N region addition and nucleotide excision from the recombining coding segments. In addition, homogeneous and fetal-like V gamma 3, V gamma 4, and V delta 1 rearrangements are observed. These rearrangements are currently difficult to interpret but may be significant with respect to whether certain homogeneous joints in normal mice are due to cellular selection or to the rearrangement process. scid TCR gamma and delta gene nucleotide sequences also reveal direct V-J delta joining, inter-(V-J-C gamma) cluster joining, and the possibility of inversional rearrangement at the gamma locus. Short sequence homologies may contribute to V(D)J recombination and to the rescue of blocked coding joints.

Animals↗
PubMed1991

Inhibition of murine natural killer cell differentiation by dehydroepiandrosterone.

Dehydroepiandrosterone (DHEA) is a naturally occurring steroid. We have previously shown that dietary DHEA (0.45% wt/wt) inhibits murine lymphopoiesis but not myelopoiesis. To assess the effect of DHEA on stages of natural killer (NK) cell differentiation, lethally irradiated mice fed DHEA or not were infused with 10(6) or 20 x 10(6) syngeneic bone marrow cells (BMC) as a source of transplantable NK cell progenitors. The differentiation of progenitor cells to lytic NK cells was assessed by the ability to clear radiolabeled YAC-1 tumor cells from the lungs. DHEA-fed recipients of 10(6) or 20 x 10(6) BMC failed to generate NK activity. Because NK progenitor cells are believed to differentiate into interleukin-2 (IL-2)-responsive precursor cells before maturation, BMC from recipient mice were cultured with IL-2 and the generation of NK cells was assessed. DHEA feeding prevented the generation of IL-2-responsive precursor cells in recipients of 10(6) BMC, but this inhibition was overcome in recipients of 20 x 10(6) BMC. To evaluate the capacity of stem cells to generate NK progenitor cells in DHEA-fed mice, the ability of marrow cells from primary recipients to generate NK activity in irradiated secondary recipients was determined. The production of NK progenitors was inhibited 20-fold. Thus, DHEA appears to inhibit the generation of NK progenitors from more primitive stem cells, the differentiation of progenitors into IL-2-responsive precursors cells and the maturation of IL-2-responsive precursor cells into mature NK cells.

Animals↗