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S Narayan

Publications and source records attributed to S Narayan.

At least 37 records · Page 2Linked to original sources
PubMed2001

Acute lymphoblastic leukaemia with giant intracytoplasmic inclusion--a case report.

Acute Lymphoblastic Leukaemia (ALL) with intracytoplasmic inclusions is a rare and unusual subtype of acute leukaemia. Here we describe a case of ALL with intracytoplasmic inclusions in an adult female. These inclusions stained negative for Myeloperoxidase (MPO), Sudan Black B (SBB) and Alpha-naphthyl acetate estarase (ANAE) and positive for Periodic Acid Schiff (PAS). This case is being presented for its unusual occurrence and to recognise the characteristics of this subtype of ALL to avoid a misdiagnosis of AML (Acute Myeloid Leukaemia).

Adult↗
PubMed2000

Retroviral entry mediated by receptor priming and low pH triggering of an envelope glycoprotein.

Avian leukosis virus (ALV) has been used as a model system to understand the mechanism of pH-independent viral entry involving receptor-induced conformational changes in the viral envelope (Env) glycoprotein that lead to membrane fusion. Here, we report the unexpected finding that ALV entry depends on a critical low pH step that was overlooked when this virus was directly compared to the classical pH-dependent influenza A virus. In contrast to influenza A virus, receptor interaction plays an essential role in priming ALV Env for subsequent low pH triggering. Our results reveal a novel principle in viral entry, namely that receptor interaction can convert a pH-insensitive viral glycoprotein to a form that is responsive to low pH.

Avian Leukosis Virus↗
PubMed2000

Kinetic analysis of Sp1-mediated transcriptional activation of the human DNA polymerase beta promoter.

In the present studies, we have examined the effect of Sp1 on the activation of the human DNA polymerase beta (beta-pol), a TATA-less promoter. A HeLa cell nuclear extract (NE) based in vitro runoff transcription system of core beta-pol promoter human DNA (pbetaP8) three-step kinetic model of transcription initiation were used to describe the kinetic effect of Sp1. The results showed that distal Sp1-binding sites in the core beta-pol promoter are important for transcriptional activation of the pbetaP8 promoter. A detailed kinetic analysis showed that Sp1 stimulates the activity of the pbetaP8 promoter through distal Sp1-binding sites by increasing the amount of recruitment, instead of stimulating the apparent rate of RPc assembly (k1). There was no significant effect of Sp1 on the apparent rate of open complex (RPo) formation (k2) or on the apparent rate of promoter clearance (k3) of the pbetaP8 promoter. These studies define the kinetic mechanisms by which Sp1 may regulate the rate of transcript formation of the pbetaP8 promoter, and these results may have implications for Sp1 regulation of TATA-less promoters.

DNA Polymerase beta↗
PubMed2000

Kinetic analysis of Sp1-mediated transcriptional activation of a TATA-containing promoter.

Using a HeLa cell nuclear extract (NE)-based in vitro runoff transcription system, we have examined the effect of Sp1 on the activation of a TATA-containing chimeric DNA polymerase beta (pAS8) promoter. The results demonstrated that the TATA element-dependent basal activity of the pAS8 promoter was stimulated 4-fold by supplementation of a Sp1-depleted HeLa cell nuclear extract (NEd) with purified human Sp1, indicating that pAS8 promoter activity is dependent upon Sp1. A detailed kinetic analysis based on a three-step kinetic model of transcription initiation showed that Sp1 stimulates the activity of the pAS8 promoter by increasing the amount of closed preinitiation complex (RP(c)) assembly as well as by enhancing the rate of promoter clearance (k(3)). There was no significant effect of Sp1 on the apparent rate of open complex (RP(o)) formation (k(2)) of the pAS8 promoter. These studies define more precisely the kinetic mechanisms by which Sp1 may regulate the rate of transcript formation of a TATA-containing promoter.

Base Sequence↗
PubMed2000

Anvirzel, an extract of Nerium oleander, induces cell death in human but not murine cancer cells.

The purpose of this study was to examine the mechanism(s) and differential cell-killing effects of Anvirzel, an extract of oleander (Nerium oleander; family-Apocynaceae), and its derivative compound Oleandrin on human, canine and murine tumor cells. Cells received different concentrations of Anvirzel (1.0 ng/ml to 500 microg/ml) or Oleandrin (0.01 ng/ml to 50 microg/ml) in both continuously treated and pulse-treated/recovery cultures. The cytotoxicity of these compounds was then determined. Both Anvirzel and Oleandrin were able to induce cell killing in human cancer cells, but not in murine cancer cells; the cell-killing potency of Oleandrin was greater than that of Anvirzel. Canine oral cancer cells treated with Anvirzel showed intermediate levels of response, with some abnormal metaphases and cell death resulting from the treatment. From these results we conclude that Anvirzel and Oleandrin act in a species-specific manner, and while testing the effectiveness of a new compound for cancer treatment, one must use not only murine but a variety of cancer cells, including those of human origin.

Animals↗
PubMed2000

Cutaneous cryptococcus infection due to C. albidus associated with Sézary syndrome.

Cryptococcus albidus is a non-neoformans species of the genus Cryptococcus and is a rare cause of disease. There have been only 13 previously reported cases of systemic disease in which this opportunistic yeast has been isolated from the lung, cerebrospinal fluid and blood. We report the first case of cutaneous Cryptococcus infection due to the species C. albidus, in a man with Sézary syndrome.

Aged↗
PubMed2000

Leukocytosis as a harbinger and surrogate marker of Clostridium difficile infection in hospitalized patients with diarrhea.

OBJECTIVES: Clostridium difficile is the etiological agent of antibiotic-associated diarrhea and pseudomembranous colitis and is a leading cause of nosocomial diarrhea. The objective of the study was to examine if leukocytosis could be a harbinger and surrogate marker of C. difficile infection in hospitalized patients. METHODS: We retrospectively examined the medical records of 70 hospitalized patients who presented with diarrhea of variable severity and who underwent stool examination for enteric pathogens, including C. difficile. We specifically recorded the white blood cell count and the pattern and severity of leukocytosis in two groups of patients--those who were C. difficile-positive and those who were negative. RESULTS: Leukocytosis was common in C. difficile-positive patients, compared to in C. difficile-negative patients (mean 15,800/mm3 vs 7700/mm3, p < 0.01). Review of the 35 C. difficile-positive patients revealed three patterns: Pattern A) sudden WBC increase coinciding with the onset of symptoms suggestive of C. difficile; Pattern B) unexplained leukocytosis preceding the appearance of C. difficile-related diarrhea and serving as a harbinger of the infection; and Pattern C) worsening of pre-existing leukocytosis as a surrogate marker of C. difficile infection. Treatment with metronidazole led to amelioration of symptoms and normalization of the leukocyte count in all cases. CONCLUSIONS: Infection with C. difficile should be considered in the differential diagnosis of sudden onset of leukocytosis in hospitalized patients previously or concurrently treated with antibiotics. Doing so may obviate the need for expensive and time-consuming tests for other etiologies.

Clostridioides difficile↗
PubMed2000

A study of lupus anticoagulant in unexplained fetal wastage.

Lupus Anticoagulant, first discovered in patients of SLE, is now known to be associated with a wide spectrum of diseases. The presence of LA is associated with adverse fetal outcome in an obstetric population. In the present series the incidence of LA was found to be 16.6% and 80% of LA positive subgroup had an unsuccessful outcome.

Abortion, Habitual↗
PubMed2000

Acute lymphoblastic leukaemia with giant intracytoplasmic inclusions--a case report.

Acute Lymphoblastic Leukaemia (ALL) with intracytoplasmic inclusions is a rare and unusual subtype of acute leukaemia. Here we describe a case of ALL with intracytoplasmic inclusions in an adult female. These inclusions stained negative for Myeloperoxidase (MPO), Sudan Black E (SBB) and alpha-naphthyl acetate estarase (ANAE) and positive for Periodic Acid Schiff (PAS). This case is being presented for its unusual occurrence and to recognise the characteristics of this subtype of ALL to avoid a misdiagnosis of AML.

Adult↗
PubMed1999

Iodoacetoxylation of glycals using cerium(IV) ammonium nitrate, sodium iodide, and acetic acid: stereoselective synthesis of 2-deoxy-2-iodo-alpha-mannopyranosyl acetates.

[formula: see text] The reactions of glycals with ceric(IV) ammonium nitrate and sodium iodide in the presence of acetic acid provides 2-deoxy-2-iodo-alpha-mannopyranosyl acetates with good stereoselectivity. In the majority of the cases examined, the selectivity was considerably better than that from reactions using N-iodosuccinimide and HOAc.

Acetates↗
PubMed1999

Value of radiation therapy in the management of chemoresistant intermediate grade non-Hodgkin's lymphoma.

The purpose of this study was to evaluate the probability and extent of response to radiation therapy in patients with chemotherapy-resistant intermediate grade non-Hodgkin's lymphoma. Thirty-five patients with chemotherapy-resistant non-Hodgkin's lymphoma received local radiation therapy after initial treatment with at least six cycles of systemic chemotherapy. There were 17 men and 18 women in our study. Ages ranged from 15 to 68 years, median age was 42 years. Chemotherapy resistance was defined as relapse after initial chemotherapy (11 patients) or failure to achieve complete remission (partial response in 18 patients, stable disease in 1 patient, and disease progression in 5 patients). Radiation doses were between 1,980-5,040 cGy (median dose of 3,200 cGy). Treatment outcome was evaluated with respect to any subsequent relapse either within or outside the irradiated region. The 2-year actuarial survival was 65%. The cumulative incidence of isolated local failure and any local failure at 2 years were 33% and 54%, respectively. Tumors that responded to initial chemotherapy had a better local control probability than tumors that did not respond. The 2-year actuarial local failure rates for these two groups were 51% and 83%, respectively (P = 0.01). There was a trend for improved local control with radiation doses > or = 3,960 cGy, suggesting the presence of a dose-control relationship. The rate of disease progression within an irradiated region in patients with intermediate grade non-Hodgkin's lymphoma that relapsed after or failed to respond completely to full course chemotherapy was substantially higher than the historical in-field failure rates when radiation therapy was used as the sole modality of treatment. Prior response to initial chemotherapy was a predicting factor for local control following radiation therapy.

Adolescent↗
PubMed1999

Protein synthesis inhibitor-mediated stability of adenomatous polyposis coli mRNA levels in HCT-116 colon cancer cells.

We examined the effect of a protein synthesis inhibitor, cycloheximide (CHX) on the adenomatous polyposis coli (APC) mRNA levels in HCT-116 colon cancer cell line. The HCT-116 cells were treated with different concentrations of CHX for 15 h. APC, p53 and beta-actin mRNA levels were determined by Northern blotting. Results showed that APC and beta-actin mRNA levels were significantly increased in a dose-dependent manner after CHX treatment. The p53 mRNA levels were moderately increased. The increase in APC mRNA levels after CHX treatment was due to increase in its stability instead of transcription. These results provide a model for CHX-induced APC mRNA stabilization and its implication in cell cycle arrest and cell survival studies.

Adenomatous Polyposis Coli Protein↗
PubMed1999

Options, outcomes, values, likelihoods decision-making guide for patients and their families.

When family caregivers are faced with making daily decisions, they may feel burdened, frustrated, and even in conflict with other family members. The OOVL Guide is a tool to help people think about the various aspects of a decision situation and combine them to make a decision. The OOVL Guide supports nurses in their advocacy role because it affirms the importance of the clients' values and preferences. The OOVL Guide provides decision-makers, both professionals and lay people, with a structure and procedure for making choices for themselves or others.

Activities of Daily Living↗