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Biomedical subjects

S Singh

Publications and source records attributed to S Singh.

At least 199 records · Page 11Linked to original sources
PubMed2002

Radioprotection by a herbal preparation of Hippophae rhamnoides, RH-3, against whole body lethal irradiation in mice.

PURPOSE: Hippophae rhamnoides L. has been well documented to have anti-oxidative, immunostimulative and regenerative properties and therefore a herbal preparation of H. rhamnoides coded as RH-3 was investigated for its radioprotective action. MATERIALS AND METHODS: RH-3 was administered intraperitonially (i.p.) to mice 30 minutes before whole body irradiation and whole body survival, spleen Colony forming units (CFU) and haematological parameters were studied. To investigate free radical scavenging and antioxidant potential, Fenton reaction, radiation mediated OH radical scavenging and chemically generated superoxide anions scavenging were studied in vitro while inhibition of lipid peroxidation was studied in liver homogenate of mice. RESULTS: A dose of 30 mg/kg body weight of RH-3 rendered 82% survival as compared to no survival in irradiated control. The endogenous CFU counts in mouse spleen on 10th post-irradiation day with and without RH-3 demonstrated radioprotective effect. Various hematological parameters also corroborated the radioprotective effect of RH-3. In a dose dependent manner, RH-3 inhibited Fenton reaction and radiation mediated generation of hydroxyl radicals in vitro, superoxide anion mediated Nitroblue tetrazolium (NBT) reduction and FeSO4 mediated lipid peroxidation in liver. CONCLUSION: Free radical scavenging, acceleration of stem cell proliferation and immunostimulation are the radioprotective attributes, which require further investigations.

Animals↗
PubMed2002

Mucosal protection against sulphide: importance of the enzyme rhodanese.

BACKGROUND: Hydrogen sulphide (H(2)S) is a potent toxin normally present in the colonic lumen which may play a role in ulcerative colitis (UC). Two enzymes, thiol methyltransferase (TMT) and rhodanese (RHOD), are thought to be responsible for sulphide removal but supportive evidence is lacking. AIMS: To determine the distribution of TMT and RHOD in different sites throughout the gastrointestinal tract and their efficacy as detoxifiers of H(2)S. METHODS: Enzyme activities were measured in normal tissue resected from patients with cancer. TMT and RHOD activities were determined using their conventional substrates, 2-mercaptoethanol and sodium thiosulphate, respectively. For measurement of H(2)S metabolism, sodium sulphide was used in the absence of dithiothreitol. Thiopurine methyltransferase (TPMT), which in common with TMT methylates sulphydryl groups but is not thought to act on H(2)S, was also examined. RESULTS: TMT, RHOD, and TPMT activities using their conventional substrates were found throughout the gastrointestinal tract with highest activity in the colonic mucosa. When H(2)S was given as substrate, no reaction product was found with TMT or TPMT but RHOD was extremely active (Km 8.8 mM, Vmax 14.6 nmol/mg/min). Incubation of colonic homogenates with a specific RHOD antibody prevented the metabolism of H(2)S, indicating that RHOD is responsible for detoxifying H(2)S. A purified preparation of RHOD also detoxified H(2)S. CONCLUSIONS: RHOD, located in the submucosa and crypts of the colon, is the principal enzyme involved in H(2)S detoxication. TMT does not participate in the detoxication of H(2)S.

Adult↗
PubMed2002

Human strongyloidiasis in AIDS era: its zoonotic importance.

Human strongyloidiasis is caused by a nematode Strongyloides stercoralis. Many species cause strongyloidiasis in animals. The parasite has predilection to one host only but the host specificity is not strict. When animal species infects humans there is intense allergic reaction in the form of cutaneous larva currens and larva migrans. Therefore, strongyloidiasis in strict terms is a zoonotic disease. The strongyloides species have three stages. The parasitic form inside the host, the free form stage in the soil or water that moults to infective third stage. The later infects the host through skin and migrate to the heart and lung and finally swallowed back to cause intestinal infection. However, in some cases intense pulmonary manifestations may take place. The Strongyloides stercoralis has unique feature of moulting from parasitic form to infective stage within the body, rather than coming out and forming free living stage and causing autoinfection. This may lead to latent infection for indefinite period in an immunocompetant person but fatal hyper or disseminated infection in immunocompromised person like patients of AIDS, organ transplant recipients, cancer and other patients put on immunosuppressive therapy, in whom it can involve any organ of the body. Because this group of patients in last few years have increased tremendously in Africa and South-East Asia, more and more cases of strongyloidiasis are being reported in english literature. The diagnosis of intestinal strongyloidiasis is made by repeated stool smear examinations and in extraintestinal strongyloidiasis the appropriate specimen is examined for the rhabditiform larvae. Recently serological tests have also been developed that can be used for epidemiological purposes. The drug of choice for the treatment of strongyloidiasis remains thiabendazole but due to its unacceptable side effects other medicines like albendazole and ivermectine are being used more frequently. The prevention of the infection is possible by adopting good personal hygiene and safe drinking water supply.

Acquired Immunodeficiency Syndrome↗
PubMed2002

Cholesterol esterase and cholesterol oxidase immobilized onto arylamine glass beads.

Cholesterol esterase (CEase) from bovine pancreas and cholesterol oxidase (COD) from Bravibacterium recombinant type have been immobilized individually and co-immobilized onto arylamine glass (pore diameter 55 nm) through the process of diazotization. CEase and COD retained 92.65% and 85.54% of the initial activity with conjugation yields of 7.2 mg/g and 8.3 mg/g support respectively when immobilized individually on arylamine glass beads, but retained 89.58% of the initial activity with a conjugation yield of 2.9 mg/g support when co-immobilized on the same support. The effects of pH, temperature, time of incubation, substrate concentration, serum inorganic salts & metabolites, thermal stability, storage stability in cold and reusability on the immobilized enzymes were studied and compared with those of free enzymes. The analytic use of both individually immobilized and co-immobilized enzymes in discrete analysis of total and free cholesterol in serum is demonstrated.

Amines↗
PubMed2002

Paradoxical reaction in HIV and tuberculosis coinfection.

Occurrence of paradoxical reaction following institution of antiretroviral therapy to patients with HIV and tuberculosis coinfection who are already on antitubercular therapy is distinctly uncommon. In this report we describe one such case and emphasize that such a reaction does not imply discontinuation of therapy.

AIDS-Related Opportunistic Infections↗
PubMed2002

Hepatorenal syndrome: pathophysiology and treatment.

The hepatorenal syndrome (HRS) is a unique form of acute renal failure with entirely normal renal histology in advanced liver disease. Its diagnosis is made by exclusion of all causes of renal failure and by all the five major criteria as set by the International Ascites Club. The presence of hepatomegaly, poor nutritional status, and oesophageal varices at endoscopy are associated with a high risk of HRS. The liver tests, the Child-Pugh score, are of no value in prediction of its occurrence. Contraction of the effective blood volume, which may lead to renal hypoperfusion with preferential renal cortical ischaemia, is proposed pathogenesis of the condition. Because understanding of the pathogenesis of HRS is incomplete, therapy is supportive only. Optimal fluid management is vital as there is almost invariably a reduction in effective arterial blood volume. Dopamine, frusemide and haemofiltration may be helpful in management of fluid overload but do not affect renal function. TIPS has been used successfully in small series of patients. The vasopressin analog also has been used with early excellent response. The treatment of HRS has been discouraging and the only proven cure for HRS is liver transplantation at this point of time.

Hepatorenal Syndrome↗
PubMed2002

Comparison of levels of mutans streptococci and lactobacilli in children with nursing bottle caries, rampant caries, healthy children with 3-5 dmft/DMFT and healthy caries free children.

Ten children from each group of nursing caries, rampant caries, 3-5 dmft/DMFT and caries free children were selected and plaque samples from carious lesion, early carious lesion, sound tooth surface as well as salivary sample were collected. The levels of mutans streptococci and lactobacilli were estimated at all the sample sites. The result further supported the role of mutans streptococci in the initiation and of lactobacilli in the progression of the dental caries.

Adolescent↗
PubMed2002

Acute paraplegia following viper bite.

Neurological complications following viper bite are uncommon and are generally as a result of intracerebral or subarachnoid bleed and rarely due to cerebral infarction. We report a young male who following viperine bite developed local tissue swelling, haemorrhagic manifestations due to disseminated intravascular coagulation and later developed acute flaccid paraplegia as a result of dorsal spinal cord involvement.

Acute Disease↗
PubMed2001

Impact of field vaccination with a Theileria annulata schizont cell culture vaccine on the epidemiology of tropical theileriosis.

Tropical theileriosis, caused by Theileria annulata, is an important tick-borne disease of cattle. A cell culture attenuated vaccine has been developed in our laboratory by long-term in vitro propagation of the schizont stage of the parasite. A longitudinal study was conducted at selected farms housing indigenous, cross-bred and exotic animals to investigate the effect of vaccination on the epidemiology of the disease. A total of 120 animals in 4 age groups were vaccinated with the vaccine before the onset of disease season. An equal number of age-matched animals were kept as controls at the same sites. Animals were monitored for 14 months at monthly intervals. The 97.5% vaccinated animals showed a rise in antibody titres 1 month post-vaccination, as determined by single dilution ELISA. The 78.3% of non-vaccinated animals became sero-positive over the period of observation. Mean antibody titres were significantly higher in vaccinated than non-vaccinated animals. Cross-bred animals showed higher antibody titres followed by exotic and indigenous animals in both the vaccinated and non-vaccinated groups. However, the antibody titres in animals of different ages were similar. The 36.7% vaccinated and 64.2% non-vaccinated animals became carriers (<0.5% piroplasms in erythrocytes) during the observation period. Clinical cases of theileriosis were recorded only in the non-vaccinated group suggesting that vaccinated animals were sufficiently immune to withstand field tick challenge for at least 14 months.

Animals↗
PubMed2001

A critical review of the probable reasons for the poor variable bioavailability of rifampicin from anti-tubercular fixed-dose combination (FDC) products, and the likely solutions to the problem.

The problem of poor/variable bioavailability of rifampicin, which is shown in particular when the drugs are present in anti-tubercular fixed-dose combination (FDC) products, is a matter of serious concern. There is a potential of failure of therapy in patients with an active disease. It perhaps also is a contributory factor towards the increasing resistance to anti-tubercular drugs. Unfortunately, the origin and cause of the problem is not clearly understood, though GMP and crystalline changes in the drug are invariably cited as the principal reasons. In this write-up, various probable physical and/or chemical reasons are critically reviewed. The enhanced decomposition of rifampicin in the presence of isoniazid in stomach after ingestion is indicated to be the key factor behind the problem. Some simple solutions offered by the knowledge of the cause are discussed and it is concluded that there is a need to have a multifaceted approach to handle the problem.

Animals↗