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Biomedical subjects

A Kumar

Publications and source records attributed to A Kumar.

At least 469 records · Page 26Linked to original sources
PubMed2000

Evaluation of the urological complications of living related renal transplantation at a single center during the last 10 years: impact of the Double-J* stent.

PURPOSE: We evaluated the impact of the routine use of Double-J stents for decreasing urological complications in living related renal transplantation at a single center during the last 10 years. MATERIALS AND METHODS: Our 3-phase longitudinal study included 670 consecutive living related renal transplants from 1989 to 1998. In phase 1 from 1989 to 1993 a stent was introduced as and when required in only 15 of 170 patients. In phase 2 from January 1994 to April 1995 we randomized 57 and 43 cases to stenting and no stenting, respectively. The stent was removed after 4 weeks. In phase 3 from May 1995 to December 1998 all patients received a stent, which was removed 10 to 14 days just before discharge home. We reviewed urological complications at various time frames to determine the impact of routine Double-J stenting on decreasing urological complications. RESULTS: In phase 1 the major ureteral complication rate was 8.8%, which decreased to 3% in phase 2 when half of our cases were stented. In phase 3 there was only 1 ureteral complication (0.04%) in 400 patients, of whom all received a stent. The overall ureteral complication rate in nonstented and stented cases was 8.5% (18 of 213) and 0.22% (1 of 457). There was no difference in urological complications or stent related problems whether the stent was removed at 4 or 2 weeks. However, stent removal at 2 weeks eliminated the possibility of a forgotten stent, avoided repeat hospitalization for stent removal and decreased the cost. Routine stenting was cost-effective and almost eliminated urological complications. CONCLUSIONS: Routine Double-J stenting prevents ureteral complications. Early removal at 2 weeks is advisable. The short duration of stenting is effective and saves the cost of repeat hospitalization at a later date.

Adolescent↗
PubMed2000

Recovery and identification of West Nile virus from a hawk in winter.

West Nile virus was recovered from the brain of a red-tailed hawk that died in Westchester County, N.Y., in February 2000. Multiple foci of glial cells, lymphocytes, and a few pyknotic nuclei were observed in the brain. Three to 4 days after inoculation of Vero cells with brain homogenates, cytopathic changes were detected. The presence of West Nile virus antigen in fixed cells or cell lysates was revealed by fluorescent antibody testing or enzyme-linked immunosorbent assay, respectively. Furthermore, Reverse transcriptase-PCR with primers specific for the NS3 gene of West Nile virus resulted in an amplicon of the expected size (470 bp). Electron microscopy of thin sections of infected Vero cells revealed the presence of viral particles approximately 40 nm in diameter, within cytoplasmic vesicles. The demonstration of infection with the West Nile virus in the dead of the winter, long after mosquitoes ceased to be active, is significant in that it testifies to the survival of the virus in the region beyond mosquito season and suggests another route of transmission: in this case, prey to predator.

Animals↗
PubMed2000

Cell cycle-regulated transcription by the human immunodeficiency virus type 1 Tat transactivator.

Cyclin-dependent kinases are required for the Tat-dependent transition from abortive to productive elongation. Further, the human immunodeficiency virus type 1 (HIV-1) Vpr protein prevents proliferation of infected cells by arresting them in the G(2) phase of the cell cycle. These findings suggest that the life cycle of the virus may be integrally related to the cell cycle. We now demonstrate by in vitro transcription analysis that Tat-dependent transcription takes place in a cell cycle-dependent manner. Remarkably, Tat activates gene expression in two distinct stages of the cell cycle. Tat-dependent long terminal repeat activation is observed in G(1). This activation is TAR dependent and requires a functional Sp1 binding site. A second phase of transactivation by Tat is observed in G(2) and is TAR independent. This later phase of transcription is enhanced by a natural cell cycle blocker of HIV-1, vpr, which arrests infected cells at the G(2)/M boundary. These studies link the HIV-1 Tat protein to cell cycle-specific biological functions.

Cell Cycle↗
PubMed2000

Pathogenic simian/human immunodeficiency virus SHIV(KU) inoculated into immunized macaques caused infection, but virus burdens progressively declined with time.

Using the simian immunodeficiency virus/human immunodeficiency virus (SHIV)-macaque model of AIDS, we had shown in a previous report that a live, nonpathogenic strain of SHIV, further attenuated by deletion of the vpu gene and inoculated orally into adult macaques, had effectively prevented AIDS following vaginal inoculation with pathogenic SHIV(KU). Examination of lymph nodes from the animals at 18 weeks postchallenge had shown that all six animals were persistently infected with challenge virus. We report here on a 2-year follow-up study on the nature of the persistent infections in these animals. DNA of the vaccine virus was present in the lymph nodes at all time points tested, as far as 135 weeks postchallenge. In contrast, the DNA of SHIV(KU) became undetectable in one animal by week 55 and in three others by week 63. These four macaques have remained negative for SHIV(KU) DNA as far as the last time point examined at week 135. Quantification of the total viral DNA concentration in lymph nodes during the observation period showed a steady decline. All animals developed neutralizing antibody and cytotoxic-T-lymphocyte responses to SHIV(KU) that persisted throughout the observation period. Vaccine-like viruses were isolated from two animals, and a SHIV(KU)-like virus was isolated from one of the two macaques that remained positive for SHIV(KU) DNA. There was no evidence of recombination between the vaccine and the challenge viruses. Thus, immunization with the live vaccine not only prevented disease but also contributed to the steady decline in the virus burdens in the animals.

AIDS Vaccines↗
PubMed2000

Comparison of in house polymerase chain reaction with conventional techniques for the detection of Mycobacterium tuberculosis DNA in granulomatous lymphadenopathy.

AIMS: To evaluate the usefulness of the devR based polymerase chain reaction (PCR) in the detection of Mycobacterium tuberculosis in lymph node aspirates and tissues of lymphadenitis and to compare PCR with conventional diagnostic techniques. SUBJECTS AND METHODS: Coded specimens of fine needle aspirates and biopsies from 22 patients with tuberculous lymphadenitis, 14 patients with non-tubercular lymphadenitis, and nine patients with granulomatous lymphadenitis were processed and subjected to analysis by PCR, smear microscopy, M tuberculosis culture, histology, and cytology. RESULTS: Tuberculous lymphadenitis was correctly diagnosed by PCR in 18 patients, by culture in five patients, by histology in 13 patients, and by cytology in seven patients. PCR gave two false positive results in 14 patients with non-tubercular lymphadenitis. The sensitivity of the conventional techniques was significantly higher with biopsies (17 of 22 specimens; 77%) than with fine needle aspirates (nine of 22 specimens; 41%). However, the sensitivity of PCR was not significantly higher with biopsies (68%) in comparison with fine needle aspirates (55%). The sensitivity of either biopsy PCR or fine needle aspirate PCR was not significantly different from that of either histology combined with culture or cytology combined with culture. The overall combined specificity of PCR was 86%. Mycobacterium tuberculosis DNA was detected in six of nine patients with granulomatous lymphadenitis. CONCLUSION: PCR is the most sensitive single technique available to date for the demonstration of M tuberculosis in specimens derived from patients with a clinical suspicion of tuberculous lymphadenitis. The value of PCR lies in its use as an adjunct test in the diagnosis of tuberculous lymphadenitis, particularly in those patients where conventional methods fail. Because fine needle aspiration is not an invasive procedure, it is the procedure of choice, and PCR should be performed initially on these samples. Excisional biopsy histology and PCR should be recommended only for patients in whom fine needle aspirate PCR is negative or when there is discrepancy with the clinical impression.

Biopsy↗
PubMed2000

Recurrent synovial chondromatosis of the index finger--case report and literature review.

We report a case of synovial chondromatosis of the proximal interphalangeal joint of the dominant right index finger with a follow-up of four years. The lesion recurred within a year of complete excision of the fibrous sac containing cartilaginous nodules. Despite early recurrence and extensive calcification around the proximal phalanx, no malignant changes were noted on histological examination. The patient remains asymptomatic for two years after the second operation.

Adult↗
PubMed2000

Infiltrative nonamyloidotic monoclonal immunoglobulin light chain cardiomyopathy: an underappreciated manifestation of plasma cell dyscrasias.

BACKGROUND: Infiltrative cardiomyopathies are characterized by diastolic dysfunction. In monoclonal plasma cell dyscrasias, organ compromise may be produced by tissue deposition of monoclonal immunoglobulins or their constituent peptides independently of the effects of unbridled plasma cell proliferation. The deposits may be fibrillar, as in light chain amyloid (AL) or nonfibrillar, as in light chain deposition disease (LCDD). AL disease of the heart is a restrictive cardiomyopathy. We hypothesized that, despite differences in physical properties, nonamyloidotic light chain deposition in the myocardium could produce similar clinical and physiological abnormalities. METHODS: Cardiac tissue from five patients with LCDD and cardiac dysfunction was examined by immunohistochemical and electron microscopic techniques. Hospital charts, electrocardiograms, echocardiograms and cardiac catheterization results were reviewed. In two cases, the original echocardiograms were reanalyzed. RESULTS: The five patients with nonamyloidotic light chain deposits in the myocardium had either mechanical or electrocardiographic abnormalities. In four with adequate clinical documentation, the diastolic dysfunction and conduction abnormalities were similar or identical to that described in cardiac AL disease. CONCLUSIONS: Although nonamyloidotic immunoglobulin light chain deposits in the myocardium differ in distribution and ultrastructural organization from the fibrillar deposits of AL disease, an analogous pattern of diastolic dysfunction and conduction disturbances results. The diagnosis should be considered in patients with a plasmacytic dyscrasia and restrictive cardiomyopathy in whom Congo red staining of endomyocardial biopsy tissue is negative. The diagnosis can be established by using the appropriate immunohistochemical and ultrastructural tissue examinations.

Adult↗
PubMed2000

Relative sensitivity of undifferentiated and cyclic adenosine 3',5'-monophosphate-induced differentiated neuroblastoma cells to cyclosporin A: potential role of beta-amyloid and ubiquitin in neurotoxicity.

Cyclosporin A is routinely used in transplant therapy following allogeneic or xenogeneic tissue transplantation to prevent rejection. This immunosuppressive drug is also neurotoxic; however, its mechanisms of action for neurotoxicity are poorly understood. Undifferentiated and cyclic adenosine 3',5'-monophosphate (cAMP)-induced differentiated neuroblastoma (NB) cells were used as an experimental model to study the toxicity of cyclosporin A. Results showed that cyclosporin A promoted the outgrowth of neurites and inhibited the growth of undifferentiated NB cells. When cyclosporin A was added simultaneously with RO20-1724, an inhibitor of cyclic nucleotide phosphodiesterase, or with prostaglandin E1, a stimulator of adenylate cyclase, it markedly enhanced the growth inhibitory and differentiation effects of these cAMP-stimulating agents. In addition, cyclosporin A added to cAMP-induced differentiated NB cells caused dose-dependent degeneration of these cells as evidenced by the vacuolization of cytoplasm and the fragmentation of nuclear and cytoplasmic materials; however, neurites remained intact. Cyclosporin A alone did not alter the intensity of cell immunostaining for ubiquitin or beta-amyloid peptide (amino acids 1-14) (Abeta1-14); however, it enhanced the intensity of staining for both ubiquitin and Abeta in cells that were treated with cAMP-stimulating agents. The intensity of staining of amyloid precursor protein (amino acids 44-63) (APP44-66) did not change in any treated group, suggesting that the increase in Abeta staining is due to increased processing of APP to Abeta. We propose that one of the mechanisms of cyclosporin A-induced neurotoxicity involves increased levels of Abeta and ubiquitin.

4-(3-Butoxy-4-methoxybenzyl)-2-imidazolidinone↗
PubMed2000

alpha-Tocopherol enhances tumour growth inhibition by cis-dichlorodiammine platinum (II).

Present studies indicate that alpha-tocopherol enhances the efficacy of cisplatin as demonstrated by inoculation of Dalton's lymphoma cells incubated with either cisplatin (5 or 10 microg/ml) alone or cisplatin + alpha-tocopherol (25 or 50 microg/ml) into C3H/He mice. Tumour cells (3 x 10(6) cells/mouse) incubated with cisplatin grow slowly in syngeneic mice as indicated by the late appearance of tumour. However, mice failed to develop tumour when inoculated with tumour cells incubated with cisplatin + alpha-tocopherol. When the animals were challenged with tumour cells (3 x 10(6) cells/mouse) on the 15th day after the initial inoculation, 30-50% survived more than 60 days, with 10% tumour-free survivors being observed in some groups. Antitumour activity was higher in mice receiving lymphoma cells (3 x 10(6) cells/mouse) preincubated with cisplatin + alpha-tocopherol compared to cisplatin alone. Tumour-bearing mice receiving cisplatin in combination with different concentrations of alpha-tocopherol exhibited significantly higher (P<0.001) intratumour platinum content (123-306%) but without any change in the kidney platinum content as compared to those receiving cisplatin (5 or 10 microg/ml) alone. Enhancement of cisplatin-induced tumour growth inhibition is probably due to the modulation of tumour cell membrane permeability by alpha-tocopherol. alpha-Tocopherol might increase the influx of cisplatin into tumour cells, causing the DNA repair machinery to be less efficient due to increased efficiency of adduct formation in the DNA molecule. This effect of alpha-tocopherol can render cisplatin more effective as an antitumour agent.

Animals↗
PubMed2000

Immediate loading of implants in partially and fully edentulous jaws: a series of 27 case reports.

BACKGROUND: The concept of immediate loading of dental implants has been researched in animal and man. High predictability with titanium screw implants can be expected under certain circumstances. Delayed loading, which is empirically based, may offer roadblocks to success in the complex case. Micromotion under a denture, retention of compromised teeth, and the necessity for multiple implant surgeries complicate the situation. The present study was undertaken to demonstrate whether in partial and fully edentulous patients, titanium screw implants may be installed and loaded within 72 hours. METHODS: The study included 27 jaws (23 mandibles and 4 maxillas) in patients who refused to wear a denture or were told of the possibility of immediately loading their implants. Criteria similar to delayed loading was utilized. The patient had to have adequate volume and density for a minimum of 4 (10 mm) implants in the mandible and 6 in the maxilla, in addition to other requirements. After a thorough presurgical evaluation by the restorative dentist, a template and heat-cured/metal-reinforced provisional were fabricated. Following fixture installation, either the fixed provisional was placed or an impression was taken, and the provisional was seated within 72 hours. Once the temporary was placed, it remained until osseointegration was complete. RESULTS: Success rates similar to those in delayed loaded cases may be expected (95%). Fewer sandblasted/acid-etched titanium screws were lost than machined titanium screws. All patients went on to completion of their original prosthetic prescription. CONCLUSIONS: Patients who are partially or fully edentulous may predictably be restored with fixed implant prostheses immediately upon fixture placement if certain parameters are met.

Aged↗
PubMed2000

Relapses in multibacillary leprosy patients: effect of length of therapy.

Two groups of MB leprosy patients, one treated to the point of smear negativity (TSN) and the other given therapy for fixed duration (24 doses of WHO MB regimen) (FDT), were compared for relapse rates during treatment and in the post-treatment period. During the follow-up of 980.2 person years in 260 patients treated with FDT, 20 relapses (2.04/100 patient years) were observed. In the other group of 301 patients, who received therapy till smear negativity, 12 relapses in 1085.46 person years (1.10/100 patient years) occurred. Comparison of survival rates (without relapse) has shown that although there is no difference up to 4 years, the risk of relapse was significantly higher on longer follow-up in the FDT group. In addition, when patients were compared on the basis of initial bacterial load, it was found that the relapse rates in patients with BI > or = 4 was significantly higher (P < 0.01) in the FDT group as compared to those receiving treatment till the point of smear negativity (4.29 versus 1.27/100 patient years). All the relapsed patients responded to retreatment with the same drug combination, indicating that the exacerbation in their condition was because of insufficient treatment. It is suggested that to prevent or reduce relapses, treatment where feasible would be continued till smear negativity, at least in patients with high BI.

Adolescent↗
PubMed2000

Expanding the living related donor pool in renal transplantation: use of marginal donors.

PURPOSE: In a living related transplantation program it is not always possible to find an ideal donor. Sometimes the only available donor in the family has some benign disease or suboptimal renal anatomy or physiology, or is too old to be accepted and defined as a marginal donor. However, with proper screening the donor pool can be increased by accepting these marginal donors and treating the benign diseases which is beneficial to the donor. We evaluate the outcome of grafts from marginal donors. MATERIALS AND METHODS: From July 1988 to August 1997, 581 live related transplantations were performed. Of the donors 52 were older than 60 years and 34 had associated benign renal or nonrenal anomaly or disease. These donors were accepted after thorough questioning and consultation with family members. The recipients of graft from elderly donors were evaluated for the number of rejections, serum creatinine at last followup and graft survival. RESULTS: Of the recipients 52 received grafts from elderly donors with a mean age of 62.6+/-3.7 years. Mean followup was 34.14+/-0.7 months. The 2 and 5-year actuarial graft survival was 96% and 74%, respectively. Creatinine was normal (less than 1.5) in 37% of recipients and 1.5 to 2.5 mg.% in 46%. The rejection rate in postoperative month 1 was 29%. All donors underwent simultaneous surgery to treat the benign disease, and all did well after surgery. CONCLUSIONS: By accepting these marginal donors a 14.6% increase in the living related donor pool was achieved without compromising recipient or donor safety. Otherwise these recipients would have been forced to undergo unrelated transplantation or be maintained on dialysis, which is particularly difficult in a developing country. Donors with associated disease benefited from cure.

Female↗
PubMed2000

Mesh repair of a coccygeal hernia via an abdominal approach.

We report on the presentation and management of a patient with herniation of the rectum following a coccygectomy. We used an abdominal approach and careful pelvic dissection to define the defect in the pelvic floor at the site where coccyx used to be. Prolene mesh repair resulted in the reduction of the hernia. To our knowledge, this is the first report on the mesh repair of the coccygeal hernia via an abdominal approach.

Aged↗
PubMed2000

HIV infection among children in Barbados.

We studied a cohort of children with the human immunodeficiency virus (HIV) infection in Barbados in order to determine the prevalence of HIV infection, the clinical course including morbidity and mortality and the magnitude of the health care and social problems. Forty-seven children were diagnosed with HIV infection during the study period. The number of HIV infected children increased from 5 during 1981-85, to 14 during 1986-90, and to 21 during the 1991-95 period. The majority (91.5%) of infections resulted from perinatal transmission. Six (12.8%) cases remained asymptomatic and 41 (87.2%) were symptomatic with 19(46.3%) presenting in infancy, while 22 (53.5%) presented post-infancy. The median age at diagnosis (class P-2) was 13 months. Generalized lymphadenopathy (47.5%), hepatosplenomegaly (40.0%), failure to thrive (27.5%), persistent recurrent diarrhoea (15.0%), oral candidiasis (37.5%), Pneumocystis carinii pneumonia (37.5%), lymphoid interstitial pneumonia (12.5%) and progressive neurological disease (10.0%) were common HIV related conditions. Two children developed non-hodgkin's lymphoma. The median age at death for 23 children was 12 months, whereas the median survival after diagnosis was 4 months. Mortality was higher among those diagnosed in infancy (73.7%) as compared to those diagnosed post-infancy (42.8%). Pneumocystis carinii pneumonia was the most common (65.2%) cause of death. Paediatric HIV infection is rising and contributes considerably to infant mortality. In this study, children took longer to be symptomatic when compared to other reports. However, once symptomatic, they died early.

AIDS-Related Opportunistic Infections↗