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Biomedical subjects

N Singh

Publications and source records attributed to N Singh.

At least 19 recordsLinked to original sources
PubMed2003

Hydrolysis of fenamiphos and its oxidation products by a soil bacterium in pure culture, soil and water.

A bacterium, identified as Brevibacterium sp. MM1, readily hydrolysed fenamiphos, a widely used organophosphorus insecticide and its toxic oxides (fenamiphos sulfoxide, fenamiphos sulfone), which all contain a common P-O-C bond, in a mineral salts medium. The bacterium also hydrolysed fenamiphos and its oxides in soil and groundwater. Interestingly, fenamiphos phenol, fenamiphos sulfoxide phenol and fenamiphos sulfone phenol, formed during bacterial hydrolysis of fenamiphos and its oxides, persisted in the mineral salts medium, but were transitory in soil and groundwater due to their further metabolism by indigenous micro-organisms. The cell-free preparation (crude enzyme) of this bacterium was very effective in hydrolysing fenamiphos. This is the first report on exceptionally rapid hydrolysis of fenamiphos by a bacterium in pure cultures, soil and groundwater.

Brevibacterium↗
PubMed2003

Serum sialic acid, a reputed cardiovascular risk factor, is related to serum leptin concentrations in Fijians.

BACKGROUND: Serum sialic acid (TSA) has been shown to be a cardiovascular risk factor and an acute phase reactant, with elevated concentrations associated with increased cardiovascular mortality and to precede the onset of type 2 diabetes. AIM: The purpose of this present study was to test the hypothesis that serum TSA may be related to serum leptin concentrations in healthy individuals. METHODS: Thirty Fijian individuals were studied (8 males and 22 females). They were urban Melanesians living in Raiwaga, a suburb of Suva in Fiji. RESULTS: Serum TSA significantly correlated with subject body mass index (BMI, rho 0.39, P<0.05) and serum leptin concentration (rho 0.44, P<0.05). In stepwise multiple regression analysis serum TSA independently correlated with subject waist/hip ratio (r(2)=0.167, P<0.02) and diastolic blood pressure (r(2)=0.300, P<0.01) but not with age, BMI, serum insulin-like growth factor binding protein (IGFBP-1), fasting plasma glucose or systolic or diastolic blood pressure. CONCLUSIONS: Serum TSA is related to markers of obesity and adipose tissue metabolism which may help to explain why it is a reputed cardiovascular risk factor and why elevated serum TSA concentrations precede the development of type 2 diabetes mellitus.

Adult↗
PubMed2003

Changing epidemiology and predictors of mortality in patients with spontaneous bacterial peritonitis at a liver transplant unit.

OBJECTIVES: To determine whether antimicrobial resistance in pathogens and outcome in patients with spontaneous bacterial peritonitis (SBP) has evolved over time. METHODS: Sixty-one consecutive episodes of SBP were studied in patients with end-stage liver disease undergoing evaluation for liver transplantation between 1991 and 2001. Patients were dichotomized into a cohort between 1991 and 1995 (the earlier cohort) and 1996-2001 (the later cohort). RESULTS: Overall, 19% of all bacteria were multiply-antibiotic resistant. The frequency of multiple-antibiotic resistance in bacteria increased from 8.3% to 38.5% in the earlier as compared to the later cohort (P = 0.07). Overall, mortality at 30 days in the study patients was 26% and had remained unchanged between the two cohorts. The mortality rate was significantly higher in patients with multiply-antibiotic-resistant bacteria than in those with other bacteria (P = 0.045). However, the Child-Pugh score (P = 0.003), and renal failure (P = 0.04) were the only independently significant predictors of mortality in patients with SBP. CONCLUSIONS: Mortality in patients with end-stage liver disease who developed SBP has remained unchanged over the last decade. Although multiple-antibiotic resistance in bacteria causing SBP has increased over time, the severity of hepatic and renal dysfunction were the predominant determinants of outcome in these patients.

Adult↗
PubMed2003

The hospital- and field-based performances of the OptiMAL test, for malaria diagnosis and treatment monitoring in central India.

The performance of the OptiMAL test, to detect and differentiate Plasmodium falciparum and P. vivax, was evaluated in central India. The subjects were either symptomatic patients, who presented at a referral hospital in urban Jabalpur, or the inhabitants of remote, tribal, forested villages where malaria is a major public-health problem. In each setting, the results of conventional microscopy were used as the 'gold standard'. Under hospital conditions, the test had excellent sensitivity (100%), good specificity (97%), a high positive predictive value (98%) and a high negative predictive value (100%). The corresponding values in the field-based study in the tribal villages (100%, 67%, 84% and 100%, respectively) were almost as good. The results of OptiMAL testing reveal the decline in parasitaemias (of P. falciparum or P. vivax) after drug administration. For monitoring the effectiveness of treatment, the test could therefore be a useful alternative to microscopy, particularly (1) in places where the facilities for microscopy are poor or non-existent and (2) among hospitalized patients with severe, complicated malaria (in whom parasitaemia and drug response need to be followed very carefully). Follow-up (within 28 days of diagnosis) of the 58 malaria cases detected in the field revealed that the OptiMAL test can be used to detect re-infection with a different Plasmodium sp. (sensitivity = 100%; specificity = 100%; J-index = 1) or recrudescence/re-infection with the same Plasmodium sp. (sensitivity = 83%; specificity = 100%; J-index = 0.83) accurately. The ability to use the test to distinguish P. falciparum from P. vivax, and to identify mixed infections of these two species, is of great significance in areas where the preferred and effective therapy for P. falciparum malaria differs from that for P. vivax.

Adult↗
PubMed2003

Effect of thymosin-alpha1 on the production of nitric oxide by tumor-associated macrophages.

The present investigation was conducted to study the effect of thymic peptide: thymosinalpha1 (thyalpha1) on the activation of tumor associated mphi (TAM) obtained from mice bearing a transplantable T cell lymphoma of spontaneous origin designated as Dalton's lymphoma, to produce nitric oxide (NO). It was found that in vivo administration of aqueous thymic extract obtained from thymus of normal mice or thyalpha1 could activate the TAM to produce enhanced amount of NO which was further augmented on in vivo treatment of these TAM by LPS. These observations suggest that thyalpha1 could prime TAM for activation by second signal of LPS. The study also presents evidence that tumor cell elaborate factors that enhance the effect of thyalpha1 on TAM for production of NO. This is the first study to show that thyalpha1 can activate TAM directly even in the absence of LPS, and may, therefore, have clinical significance.

Animals↗
PubMed2002

Effects of age on brain volume and head circumference in autism.

OBJECTIVE: To determine whether brain volume, as assessed on MRI scans, differs between individuals with autism and control subjects, and whether such differences are affected by age. BACKGROUND: Previous studies have found increased brain weight, head circumference, and MRI brain volume in children with autism. However, studies of brain size in adults with autism have yielded conflicting results. The authors hypothesize that enlargement of the brain may be a feature of brain development during early childhood in autism that normalizes with maturational processes. METHODS: The authors measured total brain volumes from 1.5-mm coronal MRI scans in 67 non-mentally retarded children and adults with autism and 83 healthy community volunteers, ranging in age from 8 to 46 years. Head circumference was also measured. Groups did not differ on age, sex, verbal IQ, or socioeconomic status. RESULTS: Brain volumes were significantly larger for children with autism 12 years old and younger compared with normally developing children, when controlling for height. Brain volumes for individuals older than age 12 did not differ between the autism and control groups. Head circumference was increased in both younger and older groups of subjects with autism, suggesting that those subjects older than age 12 had increased brain volumes as children. CONCLUSIONS: Brain development in autism follows an abnormal pattern, with accelerated growth in early life that results in brain enlargement in childhood. Brain volume in adolescents and adults with autism is, however, normal, and appears to be due to a slight decrease in brain volume for these individuals at the same time that normal children are experiencing a slight increase.

Adolescent↗
PubMed2002

Vascular phenotype in angiogenic and non-angiogenic lung non-small cell carcinomas.

We have previously described a group of non-small cell lung carcinomas without morphological evidence of neo-angiogenesis. In these tumours neoplastic cells fill up the alveoli and the only vessels present appear to belong to the trapped alveolar septa. In the present study we have characterised the phenotype of the vessels present in these non-angiogenic tumours, in normal lung and in angiogenic non-small cell lung carcinomas. The vessels, identified by the expression of CD31, were scored as mature when expressing the epitope LH39 in the basal membrane and as newly formed when expressing alphaVbeta3 on the endothelial cells and/or lacking LH39 expression. In the nine putative non-angiogenic cases examined, the vascular phenotype of all the vessels was the same as that of alveolar vessels in normal lung: LH39 positive and alphaVbeta3 variable or negative. Instead in 104 angiogenic tumours examined, only a minority of vessels (mean 13.1%; range 0--60%) expressed LH39, while alphaVbeta3 (in 45 cases) was strongly expressed on many vessels (mean 55.5%; range 5--90%). We conclude that in putative non-angiogenic tumours the vascular phenotype is that of normal vessels and there is no neo-angiogenesis. This type of cancer may be resistant to some anti-angiogenic therapy and different strategies need to be developed.

Carcinoma, Non-Small-Cell Lung↗
PubMed2002

Pyomyositis associated with bacillary angiomatosis in a patient with HIV infection.

Bacillary angiomatosis is an opportunistic infection occurring predominantly in patients with HIV infection. The manifestations of this vasculoproliferative disorder vary markedly. Virtually any organ site may be involved, singly or multiply. However cutaneous involvement can be a valuable clue to its diagnosis. We report a case of bacillary angiomatosis in an HIV-infected patient presenting as isolated pyomyositis of the right leg. The rarity of such a presentation and paucity of cutaneous lesions, as in our case, may render timely diagnosis elusive and difficult. Its recognition however, is important since bacillary angiomatosis, if untreated, is potentially fatal.

AIDS-Related Opportunistic Infections↗
PubMed2002

Usefulness of an inexpensive, Paracheck test in detecting asymptomatic infectious reservoir of plasmodium falciparum during dry season in an inaccessible terrain in central India.

OBJECTIVES: The performance of a new indigenous rapid diagnostic test, Paracheck Pf was evaluated in detection of Plasmodium falciparum in asymptomatic children in remote forest villages of Mandla district, central India to determine the lower limits of sensitivity and specificity of rapid test. METHODS: A finger prick blood sample was collected to prepare blood smear and for testing with the Paracheck test. The blood smears were read by an experienced technician blinded to the Paracheck results. The figures for specificity, sensitivity, accuracy and predictive values were calculated using microscopy as gold standard. RESULTS: The new diagnostic test had a sensitivity of 94% and a specificity of 89%. The positive and negative predictive values were 71% and 98%, respectively. The J -index was 0.83%. CONCLUSION: The rapid test was found to be very easy to perform and the result could be read reliably by field workers. The field evaluation with this new inexpensive test, ($0.65/test) indicates that it could be used as an epidemiological tool in the management of malaria particularly in areas where microscopy is not operationally feasible to attain the goal of the roll back malaria initiative.

Adolescent↗
PubMed2002

Effect of prenatal auditory enrichment on developmental expression of synaptophysin and syntaxin 1 in chick brainstem auditory nuclei.

Neural activity plays an important role in shaping the developing brain. We have determined the consequence of increased auditory stimulation on the developmental profile of synaptic proteins, synaptophysin and syntaxin 1, in the chick brainstem auditory nuclei, nucleus magnocellularis and nucleus laminaris, by immunohistochemistry and western blotting techniques. The chick embryos were provided with patterned sounds of species-specific calls or musical notes of a sitar, a stringed instrument, in a graded manner from embryonic day 10 (E10) through hatching, for 15 min every hour. During normal synaptogenesis of nucleus magnocellularis and nucleus laminaris, synaptophysin immunoreactivity increased significantly from E8 to E20, in parallel with synapse formation, and reduced at hatching. The embryos receiving species-specific sound stimuli exhibited a similar pattern with higher levels of immunoreactivity, though the difference between the study groups was not statistically significant. The music stimulated embryos showed an earlier peak at E16, followed by a gradual decline until hatching. In all three groups studied, syntaxin immunoreactivity showed a surge at E12, followed by a decline at E16 and subsequent stabilization. The stimulated groups continually expressed higher amounts of syntaxin immunoreactivity. The results suggest that prenatal sound stimulation enhances the normal pattern of synaptic protein expression in these auditory nuclei.

Acoustic Stimulation↗
PubMed2002

Chronic epididymitis (epididymal nodule) mimicking an adenomatoid tumor--case report with review of literature.

AIM: To describe and review the differential diagnosis of epididymal nodules and chronic epididymitis so as to have a broad view of this pathology. We have suggested a possible diagnostic algorithm for the workup of an epididymal nodule. METHODS/RESULTS: We have reported a case of a 35-year-old patient with a symptomatic palpable nodular mass in the tail of the left epididymis. Fine needle aspiration suggested an adenomatoid tumor while the surgical excision histology was reported as chronic epididymitis. CONCLUSIONS: Epididymal nodules are frequently encountered in the epididymis. Their differential diagnosis includes chronic granulomatous epididymitis, adenomatoid tumor and benign paratesticular neoplasms. We consider that it is important to distinguish epididymal nodules from benign inflammatory lesions and the threshold for a surgical excision should be low as it is therapeutic and provides a definite diagnosis. Whilst the FNAC alone may not be always adequate to confirm diagnosis, an epididymectomy may be curative as well as diagnostic in selected cases.

Adenomatoid Tumor↗