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Biomedical subjects

R C Singh

Publications and source records attributed to R C Singh.

At least 19 recordsLinked to original sources
PubMed2001

Role of positive charge of lysine residue on ribosome-inactivating property of gelonin.

The report that gelonin cross-linked with monoclonal antibodies with the use of 2-iminothiolane (2-IT) exhibited higher cytotoxicity than the conjugates prepared with the use of N-succinimidyl-3-(2-pyridylthio) propionate (SPDP) alone, has prompted us to investigate the effect of epsilon-NH2 group modification with 2-IT on the ribosome-inactivating property (RIP) of gelonin. The purified gelonin was modified with 2-IT at a different molar ratio and their effects on immunoreactivity and ribosome-inactivating property were compared with those of N-succinimidyl 6-[3-(2-pyridyldithio) propionamido] hexanoate (long chain-SPDP) and SPDP modified gelonin derivatives. Modification of single amino group with 2-IT results in about 25-50% inhibition of immunoreactivity and 60-70% loss of protein synthesis inhibition activity. Modification of 2-3 amino groups further hampers both immunoreactivity and protein synthesis inhibition property of gelonin. Both the long chain-SPDP with SPDP modifications showed more pronounced effects on immunoreactivity and RIP activity as compared to the similar ratio of 2-IT modification(s). It may, therefore, be concluded that the positive charge plays an important role in the immunological as well as the protein synthesis inhibitory effect of gelonin.

Antigens↗
PubMed2000

Current status of ribosome inactivating proteins.

Ribosome inactivating proteins (RIPs) are a group of naturally occurring plant proteins with a RNA-N-glycosidases activity which depurinate rRNA at a specific universally conserved position (i.e. cleavage of N-glycosidic bond of a specific adenine of 28S rRNA). These proteins are found in different parts of plants, in concentrations ranging from a few micrograms to several hundred mg per 100 g of plant tissues. RIPs exist in two forms, type 1 having a single polypeptide chain with a molecular mass of approximately 30 kDa possessing N-glycosidase activity; and type 2 with two or four polypeptide chains having a molecular mass of approximately 60 kDa and approximately 120 kDa respectively showing lectin activity along with N-glycosidase moiety. Such biomolecules causing cytotoxicity are being exploited for designing immunotoxins/hormonotoxins using heterobifunctional conjugates. These carrier conjugates with the RIPs can influence cellular trafficking and inhibition of protein synthesis. We are witnessing a novel protein from plants that can be utilised for various therapeutical treatments ranging from cancers, AIDS and other viral diseases of present times.

Plant Proteins↗
PubMed1999

Purification and characterisation of gelonin from seeds of Gelonium multiflorum.

Gelonin, a ribosome-inactivating protein has been isolated from the seeds of Gelonium multifluorum of Euphorbiaceae family by two methods and the results are compared. In method-I conventional aqueous extraction, cation-exchange and gel-filtration chromatography has been used. In method-II S-Sepharose fast flow gel has been used to purify the proteins from the seed extract, followed by ammonium sulfate fractionation, cation-exchange and gel-filtration chromatography. Extensive physico-chemical and immunological characterizations show that molecular weight of gelonin as determined by gel-filtration chromatography and SDS-PAGE is approximately 30 kDa. The non-proteinous material which binds to CMC-gel in association with gelonin in method-I is substantially removed when gelonin is purified by method-II. Cation exchange, G-100 chromatography, RP-HPLC and SDS-PAGE show that method-II yields 50% more purified gelonin when compared to the yield by method-I. The immunoreactivity of gelonin obtained by methods I and II vary from 22-26% and 50-66% respectively and the ribosome-inactivating property vary from 46-56% and 70-87% respectively.

Chromatography, Gel↗
PubMed1999

Modification of ovine luteinizing hormone subunits with SMPT and its effect on subunit recombination, immunological activity, receptor binding and steroidogenic activity.

The increasing use of heterobifunctional cross-linking agents in the design of defined conjugates for selective targeting and inducing immune response has prompted us to study the role of epsilon-NH2 group modification of oLH subunits, their recombination and effect on immunoreactivity, receptor binding and biological activity. The epsilon-NH2 groups of alpha oLH and beta oLH subunits were separately modified by using SMPT. The alpha oLH-SMPT modified derivatives hybridize to beta oLH. Similarly, the beta oLH-SMPT derivatives recombined with alpha oLH. The recombination was judged by gel filtration chromatography and RP-HPLC analysis. The sequential modification of subunits led to progressive reduction in immunoreactivity and receptor binding activity. The modification of six or more epsilon-NH2 groups in alpha oLH although recombine fully with native beta oLH but failed to react to anti-oLH antibody. Moreover, the steroidogenic activity was also abolished. Introduction upto four SMPT groups in alpha oLH compromised immunological and biological activities but further addition of two or more SMPT groups completely abolished antibody reactivity, receptor binding and steroidogenic activity indicating the importance of later two amino groups in the receptor binding and steroidogenic activity. The present investigation clearly demonstrate that only 1:2-3 molar ratio of oLH subunits:SMPT could generate the site(s) in the subunits of the oLH that retained reasonable immunological, receptor binding and biological activity of the hormone. Therefore, this molar ratio may be used in future for the design and synthesis of bioeffective hormonotoxins.

Animals↗
PubMed1999

Significance of charge on lysine residue of ovine luteinizing hormone on immunological and biological properties of the hormone.

In order to understand the significance of positive charge of lysine residues of ovine luteinizing hormone (oLH) on immunological and biological activity, the epsilon-NH2 group(s) of ovine LH were sequentially modified with 2-iminothiolane (2IT) that preserves the positive charge of the lysine while the overall charge of the hormone remains unchanged. These studies have also been compared with the oLH modified by N-succinimidyl 3-(2 pyridyldithio) propionate (SPDP) and succinimidyl 6-[3-(2-pyridyldithio)propionamido]hexanoate (LC-SPDP) that abolish positive charge of lysine residues. The modification primarily occurs in the alpha-subunit. Sequential modification led to progressive reduction in receptor binding and immunological activities. However, the steroidogenic activity was substantially retained. The immunoreactivity and receptor binding properties of 2IT modified oLH (oLH-2IT) were less affected when compared to SPDP (oLH-SPDP) or LC-SPDP (oLH-LC-SPDP) modified derivatives suggesting that increase in hydrophobic carbon chain in oLH-LC-SPDP molecule resulted in drastic inhibition in immunological and biological properties. But the steroidogenic potential of oLH-2IT, oLH-LC-SPDP or oLH-SPDP was relatively comparable. This suggests that a single -NH2 group modification with 2IT would generate the site in the hormone for conjugation to the toxin/carrier proteins that may retain better immunological and biological activity compared to that of SPDP or LC-SPDP modified oLH.

Animals↗
PubMed1996

The effect of induced fever on the biokinetics of norfloxacin and its interaction with probenecid in goats.

The kinetic profiles of norfloxacin were evaluated in afebrile, febrile and probenecid pre-treated (70 mg/kg orally) febrile goats after a single intravenous (i.v.) dose (5 mg/kg). Fever was induced and maintained for 12 h by injecting Escherichia coli endotoxin (0.2 microgram/kg, i.v.) and repeating it in half the dose (0.1 microgram/kg) 5 h later. The plasma pharmacokinetic values for norfloxacin were best represented using a two-compartment open model. The peak norfloxacin plasma level of 90.52 +/- 3.18 micrograms/ml attained in the probenecid pre-treated febrile goats was higher than that in the febrile (75.46 +/- 0.72 micrograms/ml) or afebrile goats (62.25 +/- 1.23 micrograms/ml). ClB and Kel values were significantly (p < 0.01) decreased in febrile compared with afebrile goats. These values were further reduced in febrile goats after probenecid pre-treatment. However, t1/2 beta was not affected by the fever-probenecid interaction. Norfloxacin may be used as an infusion with probenecid in caprine diseases where very high plasma levels are required to combat resistant organisms such as Bacteroides.

Analysis of Variance↗
PubMed1996

Role of epidural medication in the treatment of resistant low back pain.

Two hundred and eight patients of low back pain were studied in the department of orthopaedic surgery, GSVM Medical College, Kanpur. The patients were put on intensive conservative treatment in the form of analgesics, hard bed rest, spinal extension exercises, traction and lumbosacral support. Thirty-two patients did not respond to this treatment and their symptoms were of more than 6 months duration and they were subjected to epidural injection of local anaesthetic agent, saline and corticosteroids. The failed 6 cases were investigated for consideration of surgery. The aim of this study is to develop standardised strategy for the treatment of low back pain. For the low back pain patients not responding to intensive conservative treatment, an idea has been put forward in the form of epidural medication prior to considering them to surgery to prevent unnecessary incidence of "failed back". A trial of epidural injection is suggested to avoid surgery.

Adolescent↗
PubMed1991

Total lactate dehydrogenase and its isoenzyme pattern in lens, aqueous humour, and serum in cases of senile cataract.

Lens, aqueous humour and serum LDH and its isoenzyme pattern were estimated in 50 patients with senile cataract; 10 each with immature senile cortical cataract, mature senile cortical cataract, hypermature senile cortical cataract, immature senile nuclear cataract and mature senile nuclear cataract. The gradual decrease in total LDH and activity in the lens with advancement of cataract was maximum in hypermature senile cortical cataract. Aqueous LDH and its isoenzyme pattern remained unaltered with the maturity of cataract, and serum LDH and its isoenzyme pattern were found to be within normal limits. The lens LDH activity was found to be not related to the serum and aqueous humour LDH activity, but LDH3 isoenzyme showed declining trend, whereas LDH5 isoenzyme increased with the maturity of cataract. The present study concluded that significant decrease in lens LDH did not bear any relationship to LDH in serum and aqueous humour in cases of senile cataract.

Aged↗
PubMed1984

Study of anti-inflammatory activity in the leaves of Nyctanthes arbor tristis Linn.--an Indian medicinal plant.

Nyctanthes arbor tristis Linn. (Harsingar) is widely used as a decoction in the Ayurvedic system of medicine for treatment of sciatica and arthritis, but it has not yet been screened scientifically. In the present study, the water soluble portion of the alcoholic extract of the leaves of Nyctanthes arbor tristis (NAT) was screened for the presence of anti-inflammatory activity. NAT inhibited the acute inflammatory oedema produced by different phlogistic agents, viz. carrageenin, formalin, histamine, 5-hydroxytryptamine and hyaluronidase in the hindpaw of rats. The acute inflammatory swelling in the knee joint of rats induced by turpentine oil was also significantly reduced. In subacute models, NAT was found to check granulation tissue formation significantly in the granuloma pouch and cotton pellet test. Acute and chronic phases of formaldehyde induced arthritis were significantly inhibited. NAT was also found to inhibit the inflammation produced by immunological methods, viz. Freund's adjuvant arthritis and PPD induced tuberculin reaction. Thus anti-inflammatory activity in leaves of Harsingar supports its use in various inflammatory conditions by the followers of the Ayurvedic system of medicine.

Animals↗