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Biomedical subjects

D Kumar

Publications and source records attributed to D Kumar.

At least 217 records · Page 12Linked to original sources

Pediatric AIDS and advanced directives: a three-year prospective study in New York State.

Most HIV-infected families currently receive their care in an ambulatory setting. Ambulatory care provides greater means of medical care, and planning for the infected family members. Advanced Directives (AD) and Do Not Resuscitate (DNR) for adults are now discussed in an ambulatory setting rather than under the duress of a hospital admission. We felt it is important to examine the practice of discussing AD/DNR with the families of pediatric AIDS patients in an out patient setting. Twenty-one and 26 AIDS-designated centers in New York State and five major hospitals in New York City were contacted through a telephone survey in 1991 and 1994, respectively. Questions were designed to obtain demographics of the hospital, pediatric AIDS population, and their DNR/AD policies. In 1991 and 1994, the survey was conducted with the pediatric unit of hospitals with pediatric AIDS. In 1991, only 12 (75%) hospitals had an existing policy on pediatric DNR. No hospital had admitted a patient with AD/DNR obtained as an outpatient, nor were there guidelines at any hospital to approach the issue in an outpatient setting. In 1994, 20 (95%) hospitals had a DNR policy for pediatric patients. We found that even though six patients were admitted with AD obtained as outpatients, no outpatient guidelines existed for AD/DNR for pediatrics. The number of cases of pediatric AIDS in New York State increased by 29.7% for the 1991-1994 period. While pediatric DNR existed in 1991/1994, we found there were presently no guidelines for obtaining AD/DNR for pediatric AIDS patients in an ambulatory setting. Families infected with HIV should have a caring atmosphere to help them address pediatric AD/DNR with their primary care providers. However, we believe that guidelines should be developed to address this issue.

Acquired Immunodeficiency Syndrome↗

bc1-1 rearrangement and cyclin D1 protein expression in multiple lymphomatous polyposis.

Multiple lymphomatous polyposis (MLP), characterized by multiple polyps involving long segments of the gastrointestinal (GI) tract, is believed to represent GI involvement by mantle cell lymphoma (MCL), primarily based on its histologic and immunophenotypic similarities with MCL. However, rearrangement of the bcl-1 locus, the molecular lesion characteristic of MCL, has not been investigated in this group of patients. The authors evaluated the morphologic, immunophenotypic, and molecular features of 18 cases of MLP and 8 B-cell lymphomas involving the GI tract (including 6 MALT lymphomas). All MLP cases presented with GI disease, and were histologically similar to MCL. DNA extracted from formalin-fixed, paraffin-embedded tissue was analyzed for evidence of bcl-1 rearrangement by PCR, using chromosome 11 specific and consensus JH primers. Amplifiable DNA was obtained in 24 of 26 cases (16 of 18 MLP cases and 8 of 8 controls). bcl-1 rearrangement was detected in 6 of 16 cases (38%), subsequently confirmed by sequencing of the breakpoint region, and in 0 of 8 controls. Immunostaining for cyclin D1 was positive in 14 of 18 MLPs, including the 6 bcl-1 rearranged cases and negative in 6 of 6 evaluable controls. The detection of bcl-1 rearrangement and cyclin D1 expression in cases of MLP supports the view that MLP represents primary MCL, of the GI tract. These techniques may also be helpful in differentiating MLP from other GI lymphomas, particularly low grade lymphomas of MALT, when only small routinely fixed endoscopic biopsies are available.

Adult↗

Effect of hyperbaric oxygenation on existing oral mucosal carcinoma.

Hyperbaric oxygen therapy (HBO) is used to treat some complications of head and neck carcinoma treatment. Several patients treated with HBO have had rapid growth of a clinically cured squamous cell carcinoma. Prior studies have produced conflicting evidence about the effect of HBO on tumor growth. This study was undertaken to determine the effects of HBO on established squamous cell carcinoma. Forty Golden Syrian hamster cheek-pouch carcinomas were induced with the established chemical carcinogen 9,10-dimethyl-1,2-benzanthracene. Twenty hamsters underwent 30 HBO dives for 60 minutes each to 2.81 atm, while 20 served as controls. At necropsy, animals receiving HBO therapy had significantly smaller tumors (P < .05) and showed a trend toward fewer cervical metastases (P < .06). HBO therapy with coexistent carcinoma inhibited the established tumor's growth.

Animals↗

Rapid cyclic changes in density and accessibility of endometrial ligands for Escherichia coli Dr fimbriae.

The mechanisms of developing infection in young, noncompromised individuals are well understood. Colonization is prerequisite for the development of infection. In human, ligands serving bacterial colonization belong to common antigens. Consequently, a majority of individuals should be sensitive to infection at all times. We hypothesize that the temporal patterns of some infections and sensitivity to them are associated with sudden changes in the density and accessibility of common receptors. Endometrial samples from women having normal menstrual cycles were examined for histological location, receptor density, and in situ hybridization of Dr (decaying-accelerating factor) ligands for Escherichia coli Dr fimbriae. Significant up-regulation and luminal expression of Dr ligands occurred during the secretory phase, whereas receptors were expressed in the basement membrane and in smaller quantities during the proliferative phase. This observation agrees with our hypotheses that some ligands recognized by bacterial adhesins change their compartmentalization and, most importantly, that they up-regulate expression at specific times.

Adult↗

Identification of a 25-kilodalton protein of Mycobacterium bovis BCG to distinguish BCG strains from Mycobacterium tuberculosis.

Mycobacterium bovis BCG vaccine strains were compared with Mycobacterium tuberculosis by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. A 25-kDa protein observed in the BCG strains was absent in M. tuberculosis. Rabbit antibodies specific to the 25-kDa protein uniquely identified this protein in BCG strains but not in M. tuberculosis. It is suggested that the 25-kDa protein and polyclonal antibodies directed against this antigen can be exploited to distinguish BCG strains from M. tuberculosis.

Antibodies, Bacterial↗

Lessons from mammographic-histopathologic correlation of large-core needle breast biopsy.

A thorough understanding of the limitations of sampling and histopathologic issues affecting lesion management is critical to successful large-core (14-gauge) needle breast biopsy. The most common problems are differentiating usual hyperplasia, atypical hyperplasia, and carcinoma in situ; satisfactory sampling of microcalcifications, often present in adjacent benign and malignant processes; differentiating phyllodes tumor from cellular fibroadenoma; and assessing the extent of an in situ component in mixed invasive and in situ carcinoma. Equally important is understanding what constitutes an acceptable histopathologic result given the mammographic appearance of the lesion. Mammographers and pathologists need experience in identifying benign processes that can manifest as discrete masses at mammography and core biopsy: focal fibrosis, apocrine metaplasia, sclerosing adenosis, and fat necrosis. When present as discrete histopathologic processes at core biopsy, such diagnoses should be accepted. Nonspecific diagnoses such as "benign breast tissue" should be avoided by pathologists when a discrete process is evident; absence of a discrete finding to explain the mammographic appearance should prompt repeat core or excisional biopsy.

Adult↗

Glucose-induced transmigration of monocytes is linked to phosphorylation of PECAM-1 in cultured endothelial cells.

The adherence of circulating monocytes to the endothelium, their migration into the subendothelium, and the subsequent formation of foam cells are initial events in the pathogenesis of atherosclerosis. However, the effect of hyperglycemia on the transendothelial migration of monocytes is not known. Exposure of human umbilical vein endothelial cells (HUVEC) cultured in a Transwell chamber to 25 mM D-glucose (a concentration representing a hyperglycemic state) for 2 h resulted in a twofold increase in the migration of vitamin D3-differentiated monocyte-like HL-60 cells. The migration was inhibited by addition of either an antibody to platelet-endothelial cell adhesion molecule-1 (PECAM-1) or a protein kinase C inhibitor, GF-109203X. In HUVEC, high concentrations of D-glucose (25 mM), but not of other sugars such as L-glucose, 2-deoxyglucose, D-galactose, or D-mannitol, caused a sevenfold increase in the phosphorylation of PECAM-1 as a result of activation of protein kinase C. The 25 mM D-glucose-induced PECAM-1 phosphorylation and transmigration of monocyte-like HL-60 cells were further increased by treatment of HUVEC with the phosphatase inhibitor calyculin A. These results suggest that direct phosphorylation of PECAM-1 in response to elevated glucose promotes transendothelial migration of monocytes, contributing to accelerated atherogenesis in diabetics.

Cell Movement↗

A distinct syndrome of familial cleft lip and palate with prominent eyes and characteristic facies in two unrelated families.

A variable degree of facial and oral clefting segregating with the characteristic facies, wide set prominent eyes, a broad nasal tip, and protruding external ears is described in several individuals spread over four generations in a British family and over two generations in a Spanish family. None of the affected individuals have any other developmental anomaly. The occurrence of oral and facial clefting associated with prominent eyes and characteristic facies probably indicates the existence of a distinct autosomal dominant syndrome.

Cleft Lip↗

Central modulation of Brewer's yeast-induced peripheral inflammation by neuropeptides bradykinin and substance P.

Possible modulation of the Brewer's yeast-induced peripheral inflammation by two central neuropeptides, bradykinin and substance P (SP), was investigated in rats. Centrally administered bradykinin significantly increased pedal oedema and pain threshold whereas, SP produced significant augmentation of oedema volume and nociception. The results of the present study indicate that central bradykinin exerts pro-inflammatory and analgesic effects whereas, central SP exerts pro-inflammatory and pro-nociceptive effects on Brewer's yeast-induced peripheral inflammation.

Analgesics↗

Polymorphonuclear leukocytes in non-insulin-dependent diabetes mellitus: abnormalities in metabolism and function.

OBJECTIVE: To determine basal levels of cytosolic calcium ([Ca2+]i) and phagocytic activity in polymorphonuclear leukocytes (PMNLs) from patients with non-insulin-dependent diabetes (NIDDM). DESIGN: Prospective cohort study. SETTING: A university-county hospital. MEASUREMENTS: Cytosolic calcium levels, adenosine triphosphate (ATP) content, and phagocytosis of PMNLs from patients with NIDDM and from controls. INTERVENTION: In patients with NIDDM, we evaluated the effect of treatment with an oral hypoglycemic agent (glyburide) on [Ca2+]i levels, ATP content, and the phagocytosis of PMNLs. PATIENTS: 22 controls and 34 patients with NIDDM were examined. Fifteen patients were studied before and after 3 months of treatment with glyburide. RESULTS: Polymorphonuclear leukocytes from patients with NIDDM showed significantly elevated basal levels of [Ca2+]i (68 +/- 9.6 compared with 43 +/- 4.9 nmol/L; P < 0.01); reduced ATP content (1.30 +/- 0.58 compared with 2.35 +/- 0.45 nmol/10(6) PMNLs; P < 0.01); and impaired phagocytosis (117 +/- 21.0 compared with 145 +/- 17.4 micrograms oil/10(7) PMNLs per minute; P < 0.01) compared with controls. There was a direct and significant correlation (P < 0.01, r = 0.80) between [Ca2+]i levels in PMNLs and serum glucose levels and an inverse correlation between phagocytic ability and [Ca2+]i levels (P < 0.01; r = 0.62) as well as between phagocytic activity and fasting serum glucose levels (P < 0.01, r = 0.54) in patients with NIDDM. Glyburide therapy resulted in significant reduction in fasting serum glucose levels; in PMNLs, this treatment resulted in a significant reduction in [Ca2+]i levels, a significant increase in ATP content, and a significant improvement of phagocytosis. CONCLUSIONS: Patients with NIDDM have elevated [Ca2+]i levels in PMNLs. This abnormality is probably induced by hyperglycemia and is primarily responsible for the imparied phagocytosis seen in these patients.

Adenosine Triphosphate↗

Cooperative organization of inorganic-surfactant and biomimetic assemblies.

A model that makes use of the cooperative organization of inorganic and organic molecular species into three dimensionally structured arrays is generalized for the synthesis of nanocomposite materials. In this model, the properties and structure of a system are determined by dynamic interplay among ion-pair inorganic and organic species, so that different phases can be readily obtained through small variations of controllable synthesis parameters, including mixture composition and temperature. Nucleation, growth, and phase transitions may be directed by the charge density, coordination, and steric requirements of the inorganic and organic species at the interface and not necessarily by a preformed structure. A specific example is presented in which organic molecules in the presence of multiply charged silicate oligomers self-assemble into silicatropic liquid crystals. The organization of these silicate-surfactant mesophases is investigated with and without interfacial silicate condensation to separate the effects of self-assembly from the kinetics of silicate polymerization.

Benzene Derivatives↗

The decline in coronary artery bypass graft surgery mortality in New York State. The role of surgeon volume.

OBJECTIVE: To examine the longitudinal relationship between surgeon volume and in-hospital mortality for coronary artery bypass graft (CABG) surgery in New York State and to explain changes in mortality that occurred over time. DESIGN: Observation of clinically risk-adjusted operative mortality over time. SETTING: All 30 New York State hospitals in which CABG surgery was performed for 1989 through 1992. PATIENTS: All 57,187 patients undergoing isolated CABG surgery in New York State in 1989 through 1992 in the 30 hospitals. MAIN OUTCOME MEASURES: Actual, expected, and risk-adjusted mortality. RESULTS: Risk-adjusted in-hospital mortality decreased for all categories of surgeons. Low-volume surgeons (< or = 50 operations per year) experienced a 60% reduction in risk-adjusted mortality in the 4-year period, whereas the highest-volume surgeons (> 150 operations per year) experienced a 34% reduction. The percentage of patients undergoing CABG surgery by low-volume surgeons decreased from 7.6% in 1989 to 5.7% in 1992, a 25% decrease. CONCLUSIONS: The overall decline in risk-adjusted mortality could not be explained by shifts in patients away from low-volume surgeons to high-volume surgeons. The proportionately larger decrease in risk-adjusted mortality for low-volume surgeons could not be explained by changes in patient case mix or by improvements in the performance of surgeons with persistently low volumes. Part of the decrease was a result of the exodus of low-volume surgeons with high risk-adjusted mortality (in all years studied), the markedly better performance of surgeons who were new to the system (especially in 1991 and 1992), and the performance of surgeons who were not consistently low-volume surgeons (especially in 1992).

Clinical Competence↗

Bilateral gracilis neosphincter construction for treatment of faecal incontinence.

Neosphincter formation with gracilis muscle is used for faecal incontinence refractory to conservative measures and after failed sphincter repair. In this study both gracilis muscles were used to create a neosphincter to determine whether this provides superior physiological and clinical results. Ten patients of median age 39 (range 18-73) years were treated. The mean resting and squeeze pressures before operation were 16 (range 0-40) and 44 (range 0-68) cmH2O respectively. The operation was covered by a defunctioning loop left iliac fossa colostomy. Nine of the ten patients have had the stoma closed and are fully continent after a mean follow-up of 24 (range 6-40) months. One patient who had an ileoanal pouch and bilateral graciloplasty has urgency of defaecation. None of the patients has to wear a pad or is taking constipating agents. All nine patients have satisfactory evacuation on isotope defaecography and are continent to artificial stool. After operation the mean resting and squeeze pressures were 78 (range 70-112) and 121 (range 90-188) cmH2O respectively. Bilateral graciloplasty provides satisfactory results for grade 4 faecal incontinence refractory to other operative and non-operative measures, and may be an alternative to stimulated dynamic graciloplasty.

Adult↗

Association of hypersensitivity and carriage of dermatophytes in clinically normal sites in patients with Tinea cruris.

Forty nine patients with mycologically confirmed Tinea cruris were investigated for the association of hypersensitivity to trichophytin and the isolation of dermatophytes from clinically normal sites with chronicity and recurrence of infection. At the end of six months following specific therapy, 24 patients returned for follow up and they were similarly studied. Dermatophytes were isolated from clinically asymptomatic sites in 46% patients before treatment and in 21% of the patients on follow up. Immediate weal reaction and increased concentration of IgE antibodies were seen in 73% and 80% of the patients respectively. However, the delayed hypersensitivity reaction was more associated with patients having lesions for more than 6 months (48%) in comparison with patients with a short history (17%). On follow up after 6 months, the different hypersensitivity reactions and IgE antibody concentration maintained more or less the same association. Therefore in persistent or recurrent Tinea cruris infection, besides potential carriage in clinically normal sites, hypersensitivity to antigens of dermatophytes possibly plays an important role in pathogenicity.

Adolescent↗

Randomized trial of internal anal sphincter plication with pelvic floor repair for neuropathic fecal incontinence.

PURPOSE: This study was designed to examine the role of adjuvant internal anal sphincter plication in women with neuropathic fecal incontinence undergoing pelvic floor repair. METHODS: We completed a randomized trial with symptomatic and physiologic assessment before and after surgery. RESULTS: There was no symptomatic advantage of adding internal sphincter plication; the mean improvement of functional score was 3.61 +/- 1.82 (standard deviation; P < 0.01) following pelvic floor repair alone compared with 2.80 +/- 1.66 (standard deviation; P < 0.01) when adjuvant internal and sphincter plication was added. The addition of internal sphincter plication was associated with a significant fall in maximum anal resting and squeezing pressures (P < 0.01). CONCLUSIONS: Addition of internal sphincter plication is not advised in women with neuropathic fecal incontinence treated by pelvic floor repair.

Adult↗