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Biomedical subjects

N Naik

Publications and source records attributed to N Naik.

At least 19 recordsLinked to original sources
PubMed2006

Correlation between inflammation and oxidative stress in normocholesterolemic coronary artery disease patients 'on' and 'off' atorvastatin for short time intervals.

AIM OF THE STUDY: To assess whether variations in antioxidant and anti-inflammatory parameters occur with short term administration and discontinuation of atorvastatin in normocholesterolemic coronary artery disease (CAD) patients. METHODS: Forty CAD patients with near normal serum cholesterol levels (total cholesterol <240 mg/dl, LDL cholesterol <130 mg/dl) were continuously enrolled and randomized to groups A and B (20 patients taking atorvastatin) and groups C and D (20 patients not taking atorvastatin). Atorvastatin (10 mg/day) was continued in group A, withdrawn in group B and started in groups C and D for 6 weeks. Thereafter atorvastatin was withdrawn in group A and C, restarted in group B, and continued in group D for further 6 weeks. CRP, FRAP and TBARS were assessed at baseline, 6 weeks and 12 weeks in all the groups. RESULTS: Baseline CRP, TBARS and FRAP levels were significantly different (p < 0.05) between groups A and B and C and D at the time of enrollment, indicating lower levels of oxidative stress (FRAP-172.40 +/- 23.41 nmol Fe(2+)/l vs 142.62 +/- 15.73 nmol Fe(2+)/l and TBARS-3.66 +/- 1.14 nmol/ml vs 6.11 +/- 1.85 nmol/ml) and low grade inflammation (CRP-1.38 +/- 0.69 mg/l vs 3.19 +/- 1.77 mg/l) in statin treated groups. In group B, discontinuation resulted in increase in CRP (2.87 +/- 0.98 mg/l) and TBARS (5.75 +/- 1.35 nmol/ml) and decrease in FRAP (133.132 +/- 13.32 nmol Fe(2+)/l) and whereas group A patients did not show significant variation in values compared to baseline (CRP-1.36 +/- 0.33 mg/l, FRAP-155.45 +/- 19.51 and TBARS-4.22 +/- 0.81). Administration of atorvastatin caused a marked reduction in oxidative stress and inflammation in groups C and D (CRP-1.13 +/- 0.99 mg/l and 1.73 +/- 1.60 mg/l, FRAP-166.54 +/- 34.11 and 177.44 +/- 13.31 nmol Fe(2+)/l, TBARS-4.66 +/- 2.33 and 3.55 +/- 1.25 nmol/ml respectively). The values returned to pretreatment levels on discontinuation of the drug in group C (CRP-2.61 +/- 1.28 mg/l, FRAP-138.49 +/- 19.62 nmol Fe(2+)/l, TBARS-6.13 +/- 0.74 nmol/ml) whereas the decline was maintained in group D (CRP-1.62 +/- 1.48 mg/l, FRAP-173.07 +/- 9.03 nmol Fe(2+)/l, TBARS-3.75 +/- 1.03 nmol/ml). CONCLUSION: Administration and withdrawal of atorvastatin caused changes in markers of oxidative stress which closely correlated with changes in marker of inflammation. Further, the salutary effects were of quick onset, but were rapidly reversed on withdrawal of atorvastatin.

Atorvastatin↗
PubMed2002

Necrotizing periorbital Fusarium infection--an emerging pathogen in immunocompetent individuals.

Fungal infections of the skin and deeper tissues of the periorbital region are quite rare. We report a case of a localized, deep periorbital necrotizing Fusarium infection in an otherwise healthy, elderly lady. Since the clinical features and histopathological findings of Fusarium infection are by no means characteristic, the definitive diagnosis was achieved with the help of microbiological examination of cultured organisms. A combined medical and surgical therapy led to adequate control of infection. To conclude, localized, deep periorbital necrotizing soft tissue infection by Fusarium in an immunocompetent lady is not reported in literature. One should have a high index of suspicion for emerging fungal pathogens in the differential diagnosis of necrotizing orbital or adnexal conditions, even in an immunocompetent patient. The histologic findings of septate, branching hyphae and vascular invasion cannot distinguish Fusarium species from various other moulds such as Aspergillus species; microbiologic studies are essential for confirming the diagnosis.

Amphotericin B↗
PubMed2001

Are drugs and catheter ablation effective for treating ventricular arrhythmias in populations that cannot afford implantable cardioverter defibrillators?

Despite recent advances, ventricular arrhythmias continue to pose a therapeutic challenge, especially to the clinician in the developing world. Although the implantable cardioverter defibrillator (ICD) has improved survival in both primary and secondary prevention trials, it still remains a costly modality for the developing world. Even though certain subgroups stand to benefit unequivocally in survival from the ICD, there are others in whom this therapy may not offer a survival benefit over empiric antiarrhythmic drug therapy with amiodarone. The utility of optimized drug therapy (including either amiodarone or sotalol, b-blockers, and angiotensin-converting enzyme inhibitors) needs to be compared with the ICD in a randomized manner in these lower-risk patients with ventricular arrhythmias. The role of conventional catheter ablation techniques is mostly adjunctive to drugs and ICDs, although the newer mapping and ablation techniques may offer greater promise in the future.

Arrhythmias, Cardiac↗
PubMed2001

Etiology and management of sustained ventricular tachycardia.

Ventricular tachyarrhythmias secondary to a variety of underlying cardiovascular problems pose a therapeutic challenge to the clinician. The initial presentation may be as sudden cardiac death, which underlies its public health problem. The underlying conditions predisposing to this arrhythmia include ischemic heart disease, dilated cardiomyopathy, hypertrophic cardiomyopathy, arrhythmiogenic right ventricle dysplasia and certain postoperative states including corrective surgery for tetralogy of Fallot and valve replacement. Other causes include prolonged QT syndrome, idiopathic right and left ventricle tachycardia and bundle branch re-entry tachycardia. Ischaemic heart disease is the most common cause of ventricular tachycardia and therapy has evolved considerably over the past two decades. The development of and refinements in the implantable cardioverter-defibrillator (ICD) have introduced a new dimension in therapeutic options and markedly improved survival in these patients. Insights in the dichotomy between arrhythmia suppression and total mortality have reoriented drug therapy with a decrease in the use of sodium channel blockers. beta-blockers have emerged as antiarrhythmic drugs in their own right and their synergistic effects with amiodarone have strengthened the antiarrhythmic drug arm. The role of these drugs in patients with hemodynamically stable ventricular tachycardia, especially in relatively preserved ventricles needs to be explored. Catheter ablation techniques have provided curative therapy in patients with idiopathic and bundle branch reentry tachycardia. Further advances in radiofrequency ablation, including use of newer mapping techniques, promise a greater role for ablation of ischemic ventricular tachycardia in the future. A hybrid approach consisting of drugs, catheter ablation and/ or ICD may provide effective therapeutic approach in some situations. Further innovations and technologic developments promise a further reorientation in therapy towards identification and treatment of the underlying arrhythmogenic substrate.

Adrenergic beta-Antagonists↗
PubMed2000

Differences in the microtubule organization between normal and cml granulocytes after stimulation with chemotactic peptide.

Chemotaxis of polymorphonuclear leukocytes (PMNL) from chronic myeloid leukemia (CML) patients followed in a gradient of a chemotactic peptide n-formyl-methionyl-leucyl-phenylalanine (fMLP) is consistently defective in all the phases of the disease. Chemoattractant-induced polymerization of cytoskeletal proteins (actin and tubulin) plays a major role in regulation of cell shape and cellular motility. To study the role of microtubules in defective chemotaxis, we have compared fMLP-induced alterations in organization of microtubules in PMNL from CML patients with those from normal subjects by laser confocal microscopy. Our analysis shows differences in microtubule organization between normal and CML PMNL and suggests that both nucleation of new microtubule and elongation of pre-existing microtubules are essential for PMNL chemotaxis.

Humans↗
PubMed1999

Does treatment change the outcome of seizures and computerized tomographic lesions in intracranial granulomas?

In children, intracranial granuloma diagnosed on computerized tomography (CT) scan and presenting with seizures as the sole manifestation has traditionally been treated with antitubercular (ATB) therapy or albendazole (Alb) in addition to antiepileptic drugs (AED). This study was conducted to determine whether AED therapy alone or specific treatment (ATB + Alb) influences the outcome of seizures and the CT lesion. Sixty-eight children presenting with seizures along with intracranial granuloma on CT scan were selected for the study. They were randomly divided into two groups. Group A (n = 34) was treated with AED alone and group B (n = 34) received antitubercular therapy and albendazole in addition to AED. Seizure type was noted and electroencephalogram (EEG) and CT scan were done in all. They were followed up for a period of 2 to 9 years, during which a record of seizure count and type was maintained. CT scans were repeated at 3 monthly intervals and EEGs were repeated whenever indicated. Four patients in each group were lost to follow-up. Seizures persisted in four out of 30 in group A and six out of 30 in group B. There was no statistically significant difference (p > 0.05) in the outcome of seizures in the two groups. Taking the whole group together (n = 60), of the 13 who had presented with multiple seizures at onset, epilepsy was a sequela in five (p < 0.05); and of the 17 in whom the lesion had calcified, seizures persisted in seven (p < 0.05), irrespective of treatment modality. In conclusion, though specific treatment did not alter the outcome of seizures, children with multiple seizures at presentation and calcification of CT lesion had epilepsy as a sequela.

Adolescent↗
PubMed1998

Histopathologic changes are not specific for diagnosis of gastric antral vascular ectasia (GAVE) syndrome: a review of the pathogenesis and a comparative image analysis morphometric study of GAVE syndrome and gastric hyperplastic polyps.

We studied the nonspecific nature of the histologic findings in the gastric antral vascular ectasia (GAVE) syndrome by using a morphometric comparison with common gastric lesions including hyperplastic polyps and gastritis. Five clinicopathologically confirmed cases of GAVE syndrome and 41 cases of gastric hyperplastic polyps were diagnosed during a 5-year interval at Summa Health Systems (Akron, Ohio). These cases, as well as 16 randomly selected cases of nonspecific gastritis and 9 normal gastric antral biopsy specimens, were evaluated. A semiquantitative comparison of the light microscopic findings believed to be essential in diagnosis of GAVE syndrome, including vascular hyperplasia, mucosal vascular ectasia, intravascular fibrin thrombi, and fibromuscular hyperplasia, was performed. Image analysis morphometric measures of the area ratio (vascular area/total biopsy area), mean vascular area, and number of ectatic vessels per square millimeter of tissue were performed on the CAS 200 Image Analyzer (Becton Dickinson, San Jose, Calif). By morphometric and statistical parametric analysis, several histopathologic variables, including area ratio, mean vascular area, mucosal vascular ectasia, and fibromuscular hyperplasia, did not confidently differentiate the histologic features of gastric hyperplastic polyp from those of GAVE syndrome, but did apparently differentiate GAVE syndrome from gastritis and normal gastric mucosa. The propensity of gastric hyperplastic polyps to undergo prolapse changes and prolapse as one proposed mechanism for development of the GAVE syndrome lesion probably accounts for this morphologic similarity. Specific diagnostic histopathologic changes probably do not exist for the GAVE syndrome.

Aged↗
PubMed1997

Phagocyte chemoattractant receptors.

Myeloid cells are attracted and activated by a variety of chemoattractants that bind to G protein-coupled receptors. In the past few years, the receptors for the classical chemoattractants (fMLF, C5a, PAF) and the chemotactic cytokines, known as C-X-C and C-C chemokines, have been cloned from myeloid cells. This review briefly describes recent advances in structure-function relationships of chemotactic receptors in human leukocytes as well as activation of signaling pathways and regulation of receptor function. In neutrophils, the binding of chemoattractants mainly activates the Gi2 protein inducing PIP2 hydrolysis and activation of the MAP kinase pathway. The C-C chemokine receptor, CC CKR5, and a chemokine receptor homologue, named fusin, have been shown to be the major cofactors for HIV-1 entry in macrophages and T cells. Recent studies suggest that the phosphorylation of chemoattractant receptors is a key event that regulates their biological function.

Amino Acid Sequence↗
PubMed1997

Genital tuberculosis--a major pelvic factor causing infertility in Indian women.

OBJECTIVE: To study the effect of tuberculosis, a common infectious disease in the Indian subcontinent, on the female pelvic factor and its subsequent effect on female fertility. DESIGN: Retrospective case studies. SETTING: Department of Infertility Management and Assisted Reproduction, Jaslok Hospital and Research Centre, Bombay, India. PATIENT(S): Three hundred women, between the ages of 25 and 35 years, with tubal factor as a cause of their infertile state. RESULT(S): One hundred seventeen women with a tubal factor were found to have tuberculosis as the cause of tubal blockage. On laparoscopy, 49.5% were found to have simple tubal blockage, 15.3% showed tubo-ovarian masses, and 23.9% had a frozen pelvis. Seventy-five percent complained of menstrual irregularities, thus indicating endometrial involvement; 25.6% of these women underwent an IVF procedure. The pregnancy rate after IVF-ET was 16.6% per transfer. CONCLUSION(S): This study highlights the fact that tuberculosis, a chronic infectious disease, is one of the major etiologic factors of female tubal infertility, especially on the Indian subcontinent.

Adult↗
PubMed1997

Internalization and recycling of the C5a anaphylatoxin receptor: evidence that the agonist-mediated internalization is modulated by phosphorylation of the C-terminal domain.

The C5a anaphylatoxin receptor is a member of the G protein-coupled receptor family involved in chemoattraction and activation of myeloid cells, as well as in host defence against infection by Pseudomonas aeruginosa. Upon challenge by C5a, the C5a receptor undergoes a rapid phosphorylation on serine residues in the carboxyl-terminal region. In this study, we used cells stably transfected with either the wild-type C5a receptor, or mutants affected in their capacity to be phosphorylated, to examine the role played by phosphorylation in the intracellular trafficking of the C5a receptor. Upon agonist binding, the wild-type receptor was rapidly internalized into endosomes that cluster near the nucleus after 10 minutes. Internalization of a non-phosphorylable mutant was severely impaired relative to wild-type receptor, whereas a mutant phos-phorylated on serine 327 and/or serine 338, showed a rate of internalization intermediate between that of wild-type receptor and that of the non-phosphorylable mutant. Under continuous exposure to C5a and in the absence of protein synthesis, the C5a receptor was maintained in a highly phosphorylated state but was not degraded. Confocal microscopy and ligand-binding studies indicated that internalized receptors were recycled to the plasma membrane. During this process, receptors were dephosphorylated with kinetics that correlated with the kinetics of receptor recovery on the cell surface. Altogether, our data suggest that phosphorylation plays a key role in the intracellular trafficking of the C5a receptor. Phosphoryl-ated receptors might be recognized by an adaptor protein that interacts with the endocytic machinery.

Amino Acid Sequence↗
PubMed1992

Monoclonal antibody 14E recognizes an antigen common to human oligodendrocytes, Schwann cells, Bergmann glia, and a subpopulation of reactive glia.

The monoclonal antibody 14E immunocytochemically stains the nuclear membrane of oligodendrocytes but not myelin in tissue sections of adult normal human white matter. The nuclear membranes of Schwann cells in human peripheral nerve and cerebellar Bergmann glia were also visualized with this antibody. In actively demyelinating multiple sclerosis plaques the 14E antibody stained increased numbers of oligodendrocytes and the nuclei, perikarya and cell processes of hypertrophic glia, which were often multinucleate. Scattered small groups of these hypertrophic glia were present in areas of dense astrogliosis in acute plaques. The 14E-positive hypertrophic cells could be either a subpopulation of reactive astrocytes or bipotential glial precursors.

Antibodies, Monoclonal↗
PubMed1991

Monitoring of cyclosporine concentrations by using dry blood-spot samples.

We modified the Incstar Cyclo Trac SP kit to enable its use with dry blood-spots on filter paper. The recovery ranged from 92 to 106%. Dilution studies have shown excellent linearity and parallelism throughout the range of the assay. Precision is demonstrated by within-assay CV's of 6.6 and 4.3% at 96 and 342 micrograms/L respectively and between-assay CV's of 9.1 and 7.0% at 138 and 506 micrograms/L respectively. A comparison study (n = 209) with whole blood assay gave a correlation coefficient of 0.97, a slope of 1.04, and an intercept of 13.2. Whole blood and dry blood-spot cyclosporine assays on heart, kidney, liver, and lung transplants were also compared.

Cyclosporins↗