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Biomedical subjects

N Singh

Publications and source records attributed to N Singh.

At least 199 records · Page 11Linked to original sources
PubMed1999

Nasal carriage of and infection with Staphylococcus aureus in HIV-infected patients.

BACKGROUND: Staphylococcus aureus is a common cause of serious infection in patients infected with HIV. OBJECTIVES: To evaluate risk factors for and quantitative effect of S. aureus infection in HIV-infected patients, with special attention to nasal carriage. DESIGN: Prospective, multihospital cohort study. SETTING: Three tertiary care Veterans Affairs Medical Centers. PARTICIPANTS: 231 ambulatory HIV-infected patients. RESULTS: Thirty-four percent of patients were nasal carriers of S. aureus. Of these patients, 38% were persistent carriers and 62% were intermittent carriers. Twenty-one episodes of infection occurred in 13 patients: Ten were bacteremias (including 2 cases of endocarditis), 1 was pneumonia, and 10 were cutaneous or subcutaneous infections. Seventeen (85%) of these episodes occurred in patients with CD4 counts less than 100 cells/mm3. Recurrent infections occurred in 3 of 7 patients who survived an initial S. aureus infection. The mortality rate was higher among patients with S. aureus infection than among those without infection (P = 0.03). Factors significantly associated with S. aureus infection were nasal carriage, presence of a vascular catheter, low CD4 count, and neutropenia. Molecular strain typing indicated that for 6 of 7 infected patients, the strain of S. aureus isolated from the infected sites was the same as that previously cultured from the nares. CONCLUSION: Nasal carriage is an important risk factor for S. aureus infection in HIV-infected patients. Controlled studies are indicated to determine whether eradication of nasal carriage in a selected subset of patients (for example, those with a low CD4 cell count) might prevent invasive S. aureus infection in patients with HIV infection.

AIDS-Related Opportunistic Infections↗
PubMed1999

Quality of life, functional status, and depression in male liver transplant recipients with recurrent viral hepatitis C.

BACKGROUND: The quality of life, psychologic sequelae, and functional status of liver transplant recipients with recurrent hepatitis C virus (HCV) hepatitis have not been well defined. METHODS: Perceived quality of life, psychologic distress, depression, adaptive coping, and functional status were prospectively assessed in 59 liver transplant recipients at baseline (before transplantation) and 6 and 12 months after transplantation; comparisons were made between patients with recurrent HCV hepatitis and all other patients. RESULTS: Recurrent HCV hepatitis developed in 41% (14/34) of the patients with HCV. At 6 months, the patients with recurrent HCV hepatitis had significantly lower functional status (P=0.013) and experienced less gain in physical functioning from baseline than other patients (P=0.02). Quality of life, depression, and psychologic distress were not different at 6 months for patients with recurrent HCV hepatitis compared with all other patients. At 12 months, the patients with recurrent HCV hepatitis had significantly lower quality of life (P=0.003), greater depression (P=0.045), higher psychologic distress (P=0.05), and lower physical functioning (P=0.008) than all other patients. CONCLUSION: Recurrent HCV hepatitis in liver transplant recipients is associated with impairment in quality of life, functional status, and greater depression compared with patients who did not have HCV and those without HCV recurrence.

Adult↗
PubMed1999

Random amplified polymorphic DNA analysis of Indian scented basmati rice (Oryza sativa L.) germplasm for identification of variability and duplicate accessions, if any.

Genetic variation among the seventeen basmati rice accessions collected from the farmers' fields located at different places in India was analyzed using ten arbitrary tenmer oligonucleotide primers by the random amplified polymorphic DNA (RAPD) method. The number of polymorphic/monomorphic bands among the pairwise combinations of the accessions and the total number of bands were determined to categorize all the accessions in different groups of similarity and dissimilarity at the genetic level. The procedure described also allows the identification and discrimination of the individual genotypes of basmati rice including the identification of the duplicates in genetic resource collections.

DNA, Plant↗
PubMed1999

Encephalopathy associated with human herpesvirus 6 in a liver transplant recipient.

Recent reports have documented human herpesvirus 6 (HHV-6) as a cause of high fever, bone marrow depression, and rash in liver transplant recipients in the absence of another known pathogen. We describe a 49-year-old liver transplant recipient who developed confusion, occipital headache, and involuntary movements of the limbs 3 weeks after orthotopic liver transplantation. HHV-6 was detected in the peripheral blood using a rapid culture assay. Examination of cerebrospinal fluid by polymerase chain reaction for HHV-6 was also positive. No other pathogens were identified. The patient improved after commencement of intravenous ganciclovir therapy. This case suggests HHV-6 needs to be considered in the differential diagnosis of unexplained confusion in liver transplant recipients.

Antiviral Agents↗
PubMed1999

Effect of lithium on hepatic and serum elemental status under different dietary protein regimens.

Lithium carbonate at the dose level of 1.1 g/kg was administered in diet to normal (18% protein), low-protein- (LP; 8%) and high-protein (HP; 30% diet)-fed rats for a period of 1 mo. The LP diet resulted in a significant decrease in the hepatic levels of zinc, iron, copper, manganese, calcium, and serum levels of calcium and sodium. The HP diet caused a marked decrease in copper and calcium levels in liver, but an increase in potassium levels in serum was observed. Lithium treatment to normal rats led to a significant reduction in the hepatic contents of zinc, copper, potassium, calcium, and serum contents of potassium and sodium, whereas an elevation in serum contents of calcium was noticed. Administration of lithium to protein-deficient rats increased the hepatic concentration of manganese and serum concentration of calcium and the levels almost reached the normal limits. On the other hand, there was a marked depression in potassium contents in the serum of LP- as well as HP-fed rats following lithium treatment when compared to LP and HP groups, respectively.

Animals↗
PubMed1999

Epispadias repair using the Mitchell technique.

PURPOSE: The results of epispadias repair using Mitchell's technique in nine patients is analyzed and the advantages of the procedure discussed. METHODS: Nine boys aged between 6 weeks and 6 years underwent epispadias repair between November 1996 and March 1998 (Penopubic epispadias, inferior vesical fissure, and midpenile epispadias, one patient each; exstrophy epispadias complex, six patients). Eight patients had first attempt at repair of epispadias. Two patients had closure of exstrophy and epispadias at one stage. RESULTS: At a mean follow-up of 10 months, all children had a conical glans, eight patients had ventral orthotopic meatus, and one had coronal hypospadiac meatus. Minor penopubic fistula developed in one patient. Six patients had downward angled penis, and three had horizontal penis in a flaccid state. All children were observed to have good erections during sleep. CONCLUSIONS: Mitchell's technique of epispadias repair allows an anatomic reconstruction of the penis with superior cosmetic and functional results. Long-term follow-up studies are necessary to evaluate the genital functions.

Child↗
PubMed1999

The rod photoreceptor ATP-binding cassette transporter gene, ABCR, and retinal disease: from monogenic to multifactorial.

The ABCR gene encodes a rod photoreceptor specific ATP-binding cassette transporter. Mutations in ABCR are associated with at least four inherited retinal dystrophies: Stargardt disease, Fundus Flavimaculatus, cone-rod dystrophy, and retinitis pigmentosa. A statistically significant increase in heterozygous ABCR alterations has been identified in patients with age-related macular degeneration (AMD). A pedigree is described which manifests both Stargardt disease and AMD in which an ABCR mutation cosegregates with both disease phenotypes. These data from this case report support the hypothesis that ABCR is a dominant susceptibility locus for AMD. Recent work regarding ABCR is reviewed and a model is presented in which decreased ABCR function correlates with severity of retinal disease.

ATP-Binding Cassette Transporters↗
PubMed1999

Assay of beta-hematin formation by malaria parasite.

Novel leads are urgently required for designing antimalarials due to the reduced efficacy of presently available drugs. The malaria parasite has a unique reaction of heme polymerization, which has attracted much attention in the recent past as a target for the design of antimalarial drugs. The process is hampered by non-availability of a proper assay method. Currently available methods are cumbersome and require advanced instrumentation or radioactive substrates. Here, we are describing an assay for hemozoin formation that is simple and reproducible. This assay has routinely been used by us for the identification of potential compounds with antimalarial activity.

Animals↗
PubMed1999

Effect of lithium augmentation on the trace elemental profile in diabetic rats.

Energy dispersive X-ray fluorescence technique was employed to study the interactions among various elements, viz.: K, Zn, Br, Fe, Cu, Br & Rb in 4 groups of rats viz. control-GI, diabetic-GII (diabetes induced by i.p. administration of alloxan monohydrate at a dose level of 150 mg/kg b.w; single injection), lithium treated-GIII (lithium administered as Li2 Co3 at a dose level of 1.1 g of Li2 Co3/kg animal diet; free access; serum lithium levels--0.5-1.2 mEq/L) and lithium + diabetic rats-GIV. The different treatments continued for a total duration of 1 month. The K contents were found to be significantly lowered in all the treatment groups which was maximum (28%) in lithium treated diabetic rats. Depression in the levels of Rb was noticed in lithium treated and lithium treated diabetic (G-III and G-IV) groups. However, the levels (Rb) remained unaltered in diabetic (G-II) group. Interestingly, a significant decline was observed in Fe levels in G-III following lithium administration but the levels remained unchanged in G-IV with lithium administration to diabetic rats. On the other hand, lithium treatment to normal (G-III) and diabetic (G-IV) rats indicated statistically significant elevation in the levels of Cu and Br. However, diabetic (G-II) rats did not indicate any elevation in the levels of these two elements. Interestingly, the concentrations of Zn were found to be significantly elevated in all the treatment groups, which was maximum (37%) in G-III (lithium) group. A comparison of various elements from lithium treated diabetic group G-IV with the corresponding elements from the diabetic group G-II, implied a significant depression in K and Rb levels and a significant elevation in the levels of Br.

Animals↗
PubMed1999

Fever in liver transplant recipients in the intensive care unit.

Whether febrile illnesses in the intensive care unit (ICU) have unique spectrum, etiologies, and outcome has not been determined in liver transplant recipients. We studied 78 consecutive febrile patients over a 4-yr period; 49% (38/78) were in the ICU and 51% (40/78) were in the non-ICU setting. Of febrile patients in the ICU, 87% (33/38) had infection and 13% had non-infectious etiology for fever. Seventy-nine percent (26/33) of the infections associated with fever in the ICU were bacterial, 9% (3/33) were viral, and 9% (3/33) were fungal in etiology. Pneumonia (30%), catheter-related bacteremia (15%), and biliary tree (9%) were the predominant sources of infections associated with fever in the ICU. Bacteremia was documented in 45% of the patients with fever in the ICU. Fifty-three percent (20/38) of the febrile episodes in the ICU occurred during the initial post-transplant stay, and 47% (18/ 38) during a subsequent readmission. Pneumonia accounted for 41% of all febrile infections during the first 7 d of ICU stay, but only 14% of those after 7 d. Febrile patients in the ICU had higher APACHE II scores (p = 0.001), higher APS scores (p = 0.0001), higher bilirubin (p = 0.001), lower cholesterol (p = 0.019), higher prothrombin time (p = 0.001), were more tachycardiac (p = 0.002), and were more likely to have abnormal blood pressure (p = 0.001) than those in the non-ICU setting. Twenty-three percent of all infections in the ICU were unaccompanied by fever and 9% were accompanied by hypothermia. Mortality at 14 d (24 versus 0%, p = 0.001) and at 30 d (34 versus 5%, p = 0.001) was significantly higher in febrile patients in the ICU, as compared to the patients in the non-ICU setting. These data have implications for diagnostic evaluation and management of critically ill febrile liver transplant recipients.

Adult↗
PubMed1999

Diagnostic PCR with Leishmania donovani specificity using sequences from the variable region of kinetoplast minicircle DNA.

Kala azar or visceral leishmaniasis, a parasitic disease caused by Leishmania donovani, is presently causing an epidemic in the eastern region of India. Diagnosis of kala azar is often complicated. We developed a pair of oligonucleotides suitable as primers from the variable region of a predominant sequence class of minicircles of L. donovani. These primers were used in a nonisotopic polymerase chain reaction and found to be highly specific for the parasites of L. donovani complex. Using these primers, amplification of L. donovani kinetoplast DNA minicircle from the peripheral blood of kala azar patients results in a product of 204 bp. The patient group was comprised of individuals from a highly endemic region of India. We feel that PCR could assess the efficacy of new leishmanicidal drugs under investigation in these patients. PCR could also predict response to therapy which would be useful for both clinical and research applications.

Adolescent↗
PubMed1999

Susceptibility genes in human epilepsy.

Major advances in the identification of genetic loci and genes that predispose individuals to epilepsy have been made in the last several years. Two main themes for human, idiopathic epilepsies are emerging; genetic, or locus heterogeneity is not uncommon, and the discovery that epilepsy susceptibility genes are voltage-gated and ligand-gated ion channels. Knowledge that more than a single genetic locus is responsible for a single seizure type, along with a wide spectrum of disease mutations among families will complicate clinical, diagnostic issues. Disease gene identification, such as the two potassium ion channels (KCNQ2 and KCNQ3) for the two forms of benign familial neonatal seizures (BFNC) and the alpha4 subunit of the nicotinic receptor for autosomal dominant nocturnal frontal lobe epilepsy (ADNFLE), however, should yield significant advances in drug discoveries. Understanding the primary defect in inherited epilepsies provides for specific protein and pathway targets for potential drug intervention.

Chromosome Mapping↗
PubMed1999

Malaria and the Narmada-river development in India: a case study of the Bargi dam.

The largest river-valley development to be proposed in India is that in the Narmada valley. The building of the Bargi dam, a multi-purpose irrigation and hydro-electric project, in Jabalpur, in central India, formed part of the first phase of the development of this valley (1974-1988). Many villages and several hectares of land in three districts were submerged as the waters rose behind the dam, the worst affected area being the catchment area of the primary health centre (PHC) at Narayanganj, in Mandla district. Until recently, cases of malaria were relatively rare in Narayanganj. However, an epidemic of malaria in late 1996 claimed hundreds of lives in the area and the outbreak spread, during 1997, to new villages in the region. A review of the records collected by the National Malaria Eradication Programme (NMEP) not only indicated that the slide positivity rate (SPR) for Narayanganj increased > 7.45-fold between 1979 and 1997 but also that the slide falciparum rate (SFR) increased > 32-fold over the same period. The NMEP data available for Mandla district as a whole indicated a doubling in mean SPR and SFR between 1979 and 1997. There is no evidence that a new species of vector has established since 1979. In fact, indoor-resting densities of anophelines and of the most established vector, Anopheles culicifacies, have fallen since the dam was built, but densities of another vector, An. fluviatilis, have increased.

Adolescent↗
PubMed1999

Genotype/Phenotype analysis of a photoreceptor-specific ATP-binding cassette transporter gene, ABCR, in Stargardt disease.

Mutation scanning and direct DNA sequencing of all 50 exons of ABCR were completed for 150 families segregating recessive Stargardt disease (STGD1). ABCR variations were identified in 173 (57%) disease chromosomes, the majority of which represent missense amino acid substitutions. These ABCR variants were not found in 220 unaffected control individuals (440 chromosomes) but do cosegregate with the disease in these families with STGD1, and many occur in conserved functional domains. Missense amino acid substitutions located in the amino terminal one-third of the protein appear to be associated with earlier onset of the disease and may represent misfolding alleles. The two most common mutant alleles, G1961E and A1038V, each identified in 16 of 173 disease chromosomes, composed 18.5% of mutations identified. G1961E has been associated previously, at a statistically significant level in the heterozygous state, with age-related macular degeneration (AMD). Clinical evaluation of these 150 families with STGD1 revealed a high frequency of AMD in first- and second-degree relatives. These findings support the hypothesis that compound heterozygous ABCR mutations are responsible for STGD1 and that some heterozygous ABCR mutations may enhance susceptibility to AMD.

ATP-Binding Cassette Transporters↗