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Biomedical subjects

S Malik

Publications and source records attributed to S Malik.

At least 73 records · Page 4Linked to original sources
PubMed1999

Serum insulin and lipid profile in normal pregnant and pregnancy-induced hypertensive women from North India.

High serum insulin and lipoproteins have been reported in pregnancy-induced hypertension. Little is known about the insulin and lipoprotein profile in Indian women. To address this question we compared serum insulin and lipoproteins of women with pregnancy induced hypertension (PIH) and normotensive pregnant women. The serum insulin, triglycerides, total cholesterol and HDL cholesterol of 104 women with PIH were compared with 99 control women. Hypertensive women had significantly higher insulin (53.94 +/- 29.58 versus 37.69 +/- 17.39 pmol/L, p=0.0004) and triglyceride (3.27 +/- 1.2 versus 2.66 +/- 0.6, p=0.0001). There was no significant difference in total cholesterol and HDL cholesterol levels. Insulin levels had a positive correlation with systolic blood pressure (r=0.64) and diastolic blood pressure (r=0.55) in women with PIH. These differences persisted even after adjusting for possible confounding variables such as age, body mass index and the period of gestation. We conclude that elevated serum insulin values or insulin resistance may contribute to the pathogenesis of PIH in Indian women.

Adult↗
PubMed1999

The long-term effect of successful mitral balloon valvotomy on left atrial size.

BACKGROUND AND AIM OF THE STUDY: The study aim was to determine the extent of regression of left atrial (LA) enlargement following mitral balloon valvotomy (MBV) for mitral stenosis. METHODS: Data obtained from 205 patients before, and at a mean of 31.0 +/- 21.1 months (range: 6 to 86.3 months) after successful MBV were analyzed retrospectively. RESULTS: The invasively determined mitral valve area increased from 0.81 +/- 0.27 cm2 at baseline to 1.73 +/- 0.54 cm2 immediately after valvotomy (p <0.0001), and the mean mitral gradient fell from 15.6 +/- 5.3 to 5.4 +/- 2.5 mmHg (p <0.0001). Similar changes were noted in Doppler-determined mitral valve area (0.89 +/- 0.16 to 1.97 +/- 0.29 cm2; p <0.0001) and gradient (12.6 +/- 5.3 to 4.9 +/- 1.7 mmHg; p <0.0001). In comparison with baseline, significant (p <0.0001) reductions were noted at follow up in the echocardiographic anteroposterior (48.7 +/- 6.9 to 42.4 +/- 6.6 mm), superior-inferior (68.5 +/-8.1 to 59.6 +/- 8.2 mm) and medial-lateral LA dimension (51.2 +/- 6.7 to 44.1 +/- 7.7 mm) and calculated LA volume (91.6 +/- 29.1 to 60.7 +/- 23.8 cm3) Patients in atrial fibrillation had larger LA dimensions, but substantially smaller absolute and relative reduction in LA size at follow up than patients in sinus rhythm. Among patients with prevalvotomy LA enlargement, normalization of LA dimension at follow up was seen in 29.2% of patients in sinus rhythm, but in none of the 32 with atrial fibrillation. CONCLUSIONS: Successful MBV results in significant long-term reduction in LA size in most patients, but normalization of LA size is unusual.

Adolescent↗
PubMed1998

The Xylum Clot Signature Analyzer: a dynamic flow system that simulates vascular injury.

The Xylum Clot Signature Analyzer (CSA) is an automated, user-friendly, benchtop analyzer that assesses platelet function and coagulation in non-anticoagulated whole blood under physiological flow and temperature conditions. From blood drawn in a single venipuncture, the CSA measures: a) the time for platelets to occlude holes "punched" in a blood conduit (platelet hemostasis time or PHT); b) collagen-induced thrombus formation (CITF) as blood flows in a channel containing a collagen fiber; and c) clotting time (CT). Micrographs show platelet-rich thrombi in the punched holes and on the collagen surface after a run. PHT and CITF increased at lower shear rate, suggesting that shear activation of platelets is involved in hole closure and in collagen-induced thrombus formation. In blood mixed with anti-von Willebrand's factor (vWF) antibodies, anti-GPIb antibodies, aurin tricarboxylic acid (ATA), or anti-GPIIb-IIIa, PHT and CITF were prolonged, further supporting the reflection of platelet function by those parameters. At low shear rate (<1000 sec(-1)), native blood and blood treated with anti-vWF did not have significantly different PHTs or CITFs. At high shear rate (>6000 sec(-1)), the PHT and CITF of the anti-vWF-treated sample were significantly greater than those of the untreated sample. This supports the inhibition of shear-induced activation of platelets by anti-vWF in the CSA. Heparin-treated blood showed significantly longer CT, indicating that coagulation of blood under flow is inhibited by heparin. The CSA thus assess multiple aspects of hemostasis under near-physiological conditions.

Biological Assay↗
PubMed1998

A dynamic model for PC4 coactivator function in RNA polymerase II transcription.

Human positive cofactor (PC4) acts as a general coactivator for activator-dependent transcription by RNA polymerase II. Here we show that PC4 coactivator function, in contrast to basal (activator-independent) transcription, is dependent both on TATA binding protein (TBP)-associated factors (TAFs) in TFIID and on TFIIH. Surprisingly, PC4 strongly represses transcription initiation by minimal preinitiation complexes in the absence of TAFs and TFIIH, while simultaneously promoting the formation of these complexes. Furthermore, TFIIH and TAFII250, the largest subunit of TFIID, can both phosphorylate PC4. These results provide evidence for an inactive, PC4-induced intermediate in preinitiation complex assembly and point to TFIIH and TAF requirements for its progression into a functional preinitiation complex. Thus PC4 coactivator activity is realized in a stepwise series of events reminiscent of prokaryotic activation pathways involving conversion of inactive RNA polymerase-promoter complexes to an initiation-competent state.

Animals↗
PubMed1998

Genetic and immunologic studies of patients on procainamide.

Forty (40) patients with cardiac arrhythmias receiving procainamide (PA) therapy and 24 patients who were receiving other drugs for their cardiac disorders were investigated for class II HLA phenotypes and their DRB1*04 and DQB1*03 subtypes. Other genetic marker evaluations in the PA patients included: 1) class III MHC C4A and C4B null alleles of complement; and, 2) acetylation phenotype. Twenty (20) of the PA patients were also tested for the ability of their stimulated cells to secrete Interleukin-1 (IL-1 beta) and tumor necrosis factor (TNF alpha). We also examined the spontaneous production of these cytokines by peripheral blood leukocytes (PBL) from patients who were receiving chronic PA treatment. The results revealed no association of acetylation phenotypes with the class II HLA phenotypes nor class III MHC C4 allotypes in these patients. The results did show a significant increase in class III C4 complement allotypes in the PA patients when compared to the controls. The results also showed a significant increase in autoantibodies and DQw3 phenotypes in the PA patient group when compared to control populations. Results of spontaneous IL-1 and TNF production suggested there may be an association of select class II HLA phenotypes in some patients and this may be relevant to host responsiveness to PA treatment.

Acetylation↗
PubMed1998

Involvement of TFIID and USA components in transcriptional activation of the human immunodeficiency virus promoter by NF-kappaB and Sp1.

The purified Rel/NF-kappaB (p50/p65) complex and Sp1 markedly activate transcription from the human immunodeficiency virus type 1 (HIV-1) promoter in a highly purified HeLa reconstituted transcription system. Transcriptional activation by NF-kappaB and Sp1 requires both TFIID and the USA fraction. The USA-derived coactivators PC2 and PC4 fully reconstitute the USA coactivator activity, both by repressing the basal level of transcription and by potentiating activator function to yield large increases in the levels of transcription induction. Under limiting concentrations, PC2 and PC4 also show synergistic effects. The C-terminal portion (amino acids 416 to 550) of the p65 subunit of NF-kappaB is a potent activator when assayed as a Gal fusion in the reconstituted transcription system and interacts both with TATA-binding protein (TBP) and with several human TBP-associated factors (TAFs) that include TAFII250. The p65 activation domain mediates transcription activation in the presence of partially reconstituted TFIID species that include a minimal complex containing only TBP and TAFII250. These studies also show that, like USA components, TAFs can serve both to repress TBP-mediated transcription and, following activator interactions, to reverse the repression and effect a net increase in activity. Taken together, these data underscore the importance of both TAFs and specific USA-derived coactivators for optimal activation of the HIV-1 promoter, as well as certain parallels in their overall mechanisms of action.

DNA-Binding Proteins↗
PubMed1998

Congenital gingival granular cell tumor--a case report.

Presented here is a case report of a congenital granular cell tumor commonly known as congenital epulis. It has been found to be ten time more common in females as compared to males. The most common presenting problem is that of difficulties in feeding and respiration. Surgical excision is indicated in case the above problems are present. In the absence of any respiratory or feeding difficulties it is advisable to wait for spontaneous regression.

Female↗
PubMed1997

Subacute paraparesis induced by venous thrombosis of a spinal angiolipoma: a case report.

STUDY DESIGN: A case report of spinal extradural angiolipoma, a rare tumor that can cause spinal cord compression, is presented with a complete review of the literature related to this disorder. OBJECTIVES: To discuss venous thrombosis involving the angiolipoma in the development of subacute paraparesis. SUMMARY OF BACKGROUND DATA: This case shows that venous thrombosis of a spinal angiolipoma can precipitate the subacute onset of paraparesis. METHODS: Medical history, physical findings, and the results of imaging and histopathologic studies were analyzed to elucidate the pathogenesis of the patient's subacute onset of paraparesis. A bilateral T3-T7 laminectomy was performed, and although the tumor was extremely hemorrhagic, it was mobilized easily off the compressed dura to achieve resection. RESULTS: The postoperative course was uneventful. One month after her surgery, the patient's myelopathic symptoms had resolved, and the she was able to return to work. CONCLUSION: Because the prognosis after surgical management of these lesions is favorable, the diagnosis of thrombosis involving a spinal angiolipoma should be considered in the differential diagnosis of subacute spinal cord compression.

Acute Disease↗
PubMed1997

V(D)J recombination: modulation of RAG1 and RAG2 cleavage activity on 12/23 substrates by whole cell extract and DNA-bending proteins.

Antigen receptor gene rearrangement is directed by DNA motifs consisting of a conserved heptamer and nonamer separated by a nonconserved spacer of either 12 or 23 base pairs (12 or 23 recombination signal sequences [RSS]). V(D)J recombination requires that the rearranging DNA segments be flanked by RSSs of different spacer lengths, a phenomenon known as the 12/23 rule. Recent studies have shown that this restriction operates at the level of DNA cleavage, which is mediated by the products of the recombination activating genes RAG1 and RAG2. Here, we show that RAG1 and RAG2 are not sufficient for 12/23 dependent cleavage, whereas RAG1 and RAG2 complemented with whole cell extract faithfully recapitulates the 12/23 rule. In addition, HMG box containing proteins HMG1 and HMG2 enhance RAG1- and RAG2-mediated cleavage of substrates containing 23 RSS but not of substrates containing only 12 RSS. These results suggest the existence of a nucleoprotein complex at the cleavage site, consisting of architectural, catalytic, and regulatory components.

DNA↗
PubMed1997

Kappa-casein alleles in Zebu and cross-bred (1/2 Friesian, 1/4 Jersey, 1/4 Hariana) cattle from India using polymerase chain reaction and sequence-specific oligonucleotide probes (PCR-SSOP).

Primers and probes were designed to identify two common alleles CASK-A and CASK-B. A local breed of cross-bred cattle produced to improve the quality and quantity of milk, were studied for the alleles of kappa-casein (kappa-casein) gene using polymerase chain reaction and hybridization with sequence specific oligonucleotide probes (PCR-SSPO).

Alleles↗
PubMed1997

Community and dating violence among adolescents: perpetration and victimization.

PURPOSE: Adolescents are both the perpetrators and victims of violence in the United States. To reduce violence, it is important to identify those most at risk within particular contexts. METHODS: A social learning framework was used to investigate involvement in violence in a survey of 719 high school students. Four outcomes (community violence perpetration, community violence victimization, dating violence perpetration, and dating violence victimization) were examined as a function of demographic characteristics, exposure to violence, and several potential mediating variables. RESULTS: Exposure to weapons and violent injury in the community was the sole consistent predictor across the four outcomes. Gender generally was an important correlate of violence; there were substantial gender differences in the correlates of dating violence perpetration and victimization, but relatively few gender differences in the correlates of community violence involvement. Other demographic characteristics typically were of limited importance, and were largely accounted for by exposure to violence or other mediators. Personal norms about the circumstances under which the use of violence is perceived as justified were important for three of the four outcome: community violence perpetration, and dating violence perpetration and victimization. CONCLUSIONS: Being exposed to violence in one context appears to have crossover effects to victimization and perpetration in another context. Furthermore, victimization and perpetration often co-occur.

Adolescent↗
PubMed1997

Propantheline protects the oral mucosa after high-dose ifosfamide, carboplatin, etoposide and autologous stem cell transplantation.

Oral mucositis is a dose-limiting toxicity of high-dose etoposide regimens. Since etoposide is excreted in saliva, we tested the hypothesis that the induction of xerostomia would reduce the severity of the mucositis. We designed a phase II trial of propantheline in patients receiving high-dose ICE (ifosfamide 20 mg/m2, carboplatin 1.8 g/m2, etoposide 3 g/m2 in divided doses over 6 days) chemotherapy plus autologous hematopoietic stem cell support. We treated 31 consecutive patients and graded the oral mucositis according to WHO criteria. Mild (WHO grade 0, I, II) mucositis occurred in 28 of 31 (90%) (95% CI 74-98%) patients; severe (WHO grade III, IV) mucositis occurred in three of 31 patients (10%) (95% CI 2-25%) patients. In contrast, a published reference group treated with the same doses and schedule of ICE reported mild mucositis in 10 of 46 (22%) (95% CI 11-36%) patients and severe mucositis in 36 of 46 (78%) (95% CI 64-89%). Propantheline therapy had no protective effect on esophagitis and enteritis associated with high-dose ICE. Minor toxicities were constipation and asymptomatic tachycardia; major toxicities were palpitations in one patient and urinary retention in one patient. We conclude that anticholinergic therapy dramatically reduced the oral mucositis associated with high-dose etoposide and should be considered as a supportive care measure for patients receiving etoposide-containing regimens.

Adult↗
PubMed1997

Fine needle aspiration cytology in parotid lumps.

Over a period of two years, Fine Needle Aspiration Cytology (FNAC) was performed on 33 patients presenting with a parotid lump. Five patients were excluded as they were treated medically after FNAC report. The FNAC results of 28 cases were compared with histopathological diagnoses of surgically resected specimens. There were 8 true positive, 17 true negative, 1 false positive and 2 false negative cases. Sensitivity was 80%, specificity 94.4% and diagnostic accuracy 89.3%. FNAC is a simple quick, accurate and virtually complications free investigative modality. It is also helpful adjunct to assess preoperatively the suitability and extent of the surgical treatment.

Adolescent↗