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Biomedical subjects

G S Singh

Publications and source records attributed to G S Singh.

At least 19 recordsLinked to original sources
PubMed2004

Study of microporosity of active carbon spheres using inverse gas chromatographic and static adsorption techniques.

Active carbon spheres (ACSs) with different porous structures prepared in the laboratory were characterized by static adsorption studies and inverse gas chromatographic (IGC) technique. Surface properties such as BET surface area, micropore volume and pore size in different regions of porosity were determined using different theoretical approaches. Thermodynamic parameters such as isosteric heat of adsorption, free energy of adsorption and dispersive component of the surface energy were determined using IGC technique from corrected retention volume of normal alkanes and corresponding branched alkanes. Thermodynamic parameters were used to assess the molecular sieving property of ACSs. It is observed that thermodynamic properties strongly depend on microporous character of ACSs. The variations observed in pore size determined by both of the techniques that is by static adsorption measurements and IGC may be attributed to the variation in analysis temperature, i.e. liquid N2 temperature for adsorption studies and elevated temperature for IGC technique.

Adsorption↗
PubMed2004

Beta-lactams in the new millennium. Part-I: monobactams and carbapenems.

Beta-lactam ring-containing compounds such as penicillins, ampicillin, amoxicillin, cephalosporins and carbapenem are among the most famous antibiotics. This article reviews the recent developments in the study of such compounds. The introductory paragraph, which highlights the significance of the subject and cites most of the leading references of the previous century, is followed by an overview of beta-lactams and some novel methodologies for the synthesis of bi-, tri- and polycyclic derivatives. The rest of the sections deal with design, synthesis and biological activity of monobactams and carbapenems. Many of them have potential antibacterial activity, even against some resistant strains, and enzyme inhibitory activity.

Anti-Bacterial Agents↗
PubMed2004

Beta-lactams in the new millennium. Part-II: cephems, oxacephems, penams and sulbactam.

Beta-lactam ring-containing compounds such as penicillins, ampicillin, amoxicillin, cephalosporins and carbapenems are among the most famous antibiotics. This article reviews the recent developments in study of cephems, oxacephems, penams and sulbactam. Many of the compounds reviewed have potential antibacterial activity, even against resistant strains such as MRSA, and enzyme inhibitory activity.

Anti-Bacterial Agents↗
PubMed2001

Transport tensors in perfectly aligned low-density fluids: self-diffusion and thermal conductivity.

The modified Taxman equation for the kinetic theory of low-density fluids composed of rigid aspherical molecules possessing internal degrees of freedom is generalized to obtain the transport tensors in a fluid of aligned molecules. The theory takes care of the shape of the particles exactly but the solution has been obtained only for the case of perfectly aligned hard spheroids within the framework of the first Sonine polynomial approximation. The expressions for the thermal-conductivity components have been obtained for the first time whereas the self-diffusion components obtained here turn out to be exactly the same as those derived by Kumar and Masters [Mol. Phys. 81, 491 (1994)] through the solution of the Lorentz-Boltzmann equation. All our expressions yield correct results in the hard-sphere limit.

Journal Article↗
PubMed1999

Asymptomatic microscopic hematuria in women: case series and brief review.

Recommendations for the work-up of asymptomatic microscopic hematuria (AMH) often derive from studies including both men and women. This study was undertaken to determine whether that work-up is appropriate for a female patient population. We studied 49 women referred to a urogynecologist for AMH. Patients underwent formal urinalysis, urine culture and cytology, cystoscopy, and either renal ultrasound or intravenous urography (IVU). Highly significant lesions diagnosed were one renal cell carcinoma and one acute tubular necrosis (ATN). Moderately significant lesions included one candidal urinary tract infection. Insignificant lesions included bladder inflammation in 46 patients and renal cysts in 5. Our findings confirm the importance of the work-up of AMH in women. Ultrasound was effective in diagnosing upper tract lesions, with less cost and morbidity than IVU. Larger studies are needed to determine who should be screened, whether the work-up should differ for younger women, possible treatments for benign findings, and appropriate follow-up.

Adult↗
PubMed1994

Metastatic cervical cancer and pelvic inflammatory disease in an AIDS patient.

The Center for Disease Control (CDC) recently added invasive cervical cancer to its list of surveillance case-defining diseases, and also included cervical dysplasia, carcinoma in situ, and pelvic inflammatory disease (PID) in the classification system. There are several reported cases of cervical cancer in AIDS patients that behaved in an unusually aggressive fashion and responded poorly to therapy. In light of the above-reported cases, it may be expected that cervical cancer may manifest itself in unusual ways in HIV-positive women. A case of aggressive cervical cancer in an AIDS patient with PID is reported. She was admitted with PID and newly diagnosed cervical cancer with recurrent fever spikes despite adequate antibiotic coverage. An aspiration of a presumed psoas abscess revealed metastatic squamous cell carcinoma. These data suggest that not only are HIV-infected women at risk for aggressive and unusual presentations of cervical cancer, but also that coexistent pelvic infection may contribute to development and spread of the disease. Immunosuppression from the virus may increase the incidence and severity of neoplasia. Data suggest that cervical cancer in HIV-infected women is often of advanced stage and responds poorly to treatment. Unique treatment approaches may need to be developed as conventional strategies do not seem to be adequate. More research is required to determine what these strategies should be. Lastly, universal HIV screening of women with either PID or cervical cancer seems prudent.

Acquired Immunodeficiency Syndrome↗
PubMed1994

Synthesis and anticonvulsant activity of new 1-substituted 1'-methyl-3-chloro-2-oxospiro (azetidin-3',4-indol-2' ones).

The aim of the present research work is to discover new compounds with potential anticonvulsant activity. Several indolinone derivatives and also azetidinones are reported to have significantly anticonvulsant activity. So, it was thought considerable to synthesise compounds having both these moieties and study their anticonvulsant activity. The new spiroazetinones synthesized from the reaction of 3-(N-substituted) imino-1-methyl-indol-2-ones with chloroacetyl chloride in presence of triethylamine have been characterised on the basis of triethylamine have been characterised on the basis of satisfactory analytical and spectral data. Of the eight compounds screened in the series two compounds (3c and 3h) exhibited significant activity against MES.

Animals↗
PubMed1990

Immunosuppression due to chronic ochratoxicosis in broiler chicks.

Crystalline ochratoxin A (OA) was added to the feed of broiler chicks at 0.5 ppm and 2.0 ppm, and humoral and cell-mediated immunity (CMI) were studied. CMI was assessed by skin sensitivity testing, graft versus host (GVH) reaction and T lymphocyte count. Humoral immunity was examined by measuring the haemagglutinin (HA) response to sheep RBC (SRBC). In addition, total lymphocyte counts, total serum protein, albumin and globulin were determined and the phagocytic activity of splenic macrophages was measured in the nitroblue tetrazolium test (NBT). The weights of lymphoid organs were also recorded at post-mortem examination of the birds. Highly significant reductions in CMI were indicated by diminished skin sensitivity, GVH reactions and T lymphocyte counts. On the other hand, only the overall HA titres differed significantly between the various treatment groups. Total lymphocyte counts, total serum protein, serum albumin and serum globulin were significantly depressed on the 21st day of intoxication. The number of NBT-positive cells was drastically reduced in both the intoxicated groups compared with controls (P less than 0.05) and the weights of thymus, bursa of Fabricius and spleen of intoxicated birds were significantly reduced. The study illustrated the immunosuppressive effects of ochratoxicosis in broiler chicks.

Animals↗
PubMed1986

Lumbar discography.

Explore the source record for details and available documents.

Evaluation Studies as Topic↗
PubMed1975

Modification of acetylcholine action by bivalent cations on the perfused heart of the frog.

When frog heart is perfused with high calcium Ringer solution it may be stimulated by a low dose of acetylcholine. This stimulant action is mediated through atropine-sensitive receptors and is blocked by certain calcium antagonists such as local anesthetics, cobalt, magnesium, and phenoxybenzamine. However, the nicotinic action of high doses of acetylcholine on atropinized heart is not blocked by cobalt and magnesium ions.

Acetylcholine↗
PubMedDate not supplied

Evaluation of the direct agglutination test as an immunodiagnostic tool for kala-azar in India.

The direct agglutination test (DAT) has been assessed as a diagnostic procedure for visceral leishmaniasis. Fifty-six of 58 sera (96.5%) from confirmed cases of visceral leishmaniasis, whose bone marrow aspirates contained Leishmania donovani amastigotes, had agglutinating antibodies above the cut-off titre of 1:800. None of the sera from healthy control subjects from non-endemic or endemic areas had anti-leishmanial antibodies. Similarly, none of the sera obtained from cases of malaria or tuberculosis had agglutinating antibodies above the cut-off titre. A significant decline in agglutinating antibody titre in 3 cases following antileishmanial chemotherapy appeared to correlate with regression of clinical symptoms and the absence of amastigotes from bone marrow aspirates. One of 3 cases developed post-kala-azar dermal lesions and sera from this subject had an elevated agglutinating antibody titre. It is concluded that the DAT is a sensitive and specific test to confirm visceral leishmaniasis. As the formalin-fixed promastigotes, stained with Coomassie blue, which are used as antigen could be stored at 4 degrees C for 6 months without any loss of ability to detect anti-leishmanial antibodies, the DAT is recommended for use under field conditions.

Agglutination Tests↗