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Biomedical subjects

G K Jain

Publications and source records attributed to G K Jain.

13 recordsLinked to original sources
PubMed2006

Distribution of lovastatin to bone and its effect on bone turnover in rats.

Statins, the widely used lipid-lowering drugs, are inhibitors of 3-hydroxy-3-methyl-glutaryl coenzyme A (HMG-CoA) reductase, which catalyses a rate-limiting step in the biosynthesis of cholesterol. Many previous reports show that statins can act both as bone anabolic and as anti-resorptive agents but their beneficial effects on bone turnover are still controversial. Considering their high liver specificity and low oral bioavailability, the distribution of statins to the bone microenvironment is questionable. In this study, the distribution of lovastatin and its active metabolites to bone, with respect to plasma and liver compartments, was examined after oral and intravenous administration in female rats. As compared with oral administration, the distribution of lovastatin to the bone compartment was significantly enhanced after intravenous administration. Further, the effect of lovastatin on bone turnover was studied in-vitro and in-vivo to assess its anti-osteoporotic potential. Lovastatin acid but not lovastatin was found to inhibit parathyroid-hormone-induced bone resorption in an in-vitro chick embryo bone assay. Oral, as well as intravenous, short-term lovastatin treatment significantly reduced the serum total cholesterol, serum total alkaline phosphatase and urinary crosslinks in ovariectomized rats. In accordance with its increased distribution to the bone compartment, intravenously administered lovastatin was more effective in reducing the ovariectomy-induced increase in markers of bone metabolism, especially urinary crosslinks. The findings of this study suggest that statins inhibit bone resorption and that their anti-resorptive efficacy can be increased by administering them by routes other than oral so as to achieve their enhanced concentration in bone.

Administration, Oral↗
PubMed2002

Anilino-(2-bromophenyl) acetonitrile: a promising orally effective antileishmanial agent.

Visceral leishmaniasis (VL) or kala-azar is a worldwide disseminated intracellular infection caused by the hemoflagellate protozoan parasites Leishmania donovani. Chemotherapeutic scenario presents a deplorable picture and demands an urgent search for a new and safe anti-VL drugs, preferably active by oral route. In search of new antileishmanial agents, a total of 16 compounds belonging to the anilino-(substituted phenyl)-acetonitrile class were tested in vitro in promastigote/macrophase-amastigote systems and in vivo in L. donvoani/hamster model for their antileishmanial activity. Compound 3, anilino-(2-bromophenyl)-acetonitrile, exhibited most promising activity both in vitro at a concentration of 100 microg/ml (82.33 and 94.36% in promastigote and macrophase-amastigote systems, respectively) and in vivo at a dose of 50 mg/kg for 5 days (82.11 and 80% by i.p. and p.o. routes, respectively), hence this compound was investigated in detail. To maximize its bioavailability, dissolution profile, absorption, the compound was also tested in vivo as its soluble form. But no enhancement in activity was observed. From the results of different parameters for example ED(50) and LD(50) etc. compound 3 appears to be a potent orally effective compound which could further be investigated to establish its potential as a candidate molecule of antileishmanial therapy.

Acetonitriles↗
PubMed2000

Dysobinin, a tetranortriterpenoid.

The planar furan ring in the title compound (6beta-acetoxyazadirone, C(30)H(38)O(6)) is twisted with respect to the steroid D ring. The crystal structure is stabilized by C-H.O hydrogen bonds and van der Waals interactions.

Journal Article↗
PubMed2000

A simple and rapid evaluation of methemoglobin toxicity of 8-aminoquinolines and related compounds.

Methemoglobin, a toxic ferric form of hemoglobin, is continuously formed in normal erythrocytes, but during abnormal situations in situ, the level is enhanced. 8-Amino-quinolines and related compounds are causative agents for methemoglobin formation. Employing oxyhemoglobin, methemoglobin toxicity was about six times higher with primaquine compared to CDRI Compound 80/53 at 10(-9) M concentration. Methemoglobin reductase activity was also completely inhibited by primaquine, whereas 24% inhibition was noted in the case of 80/53 at the same concentrations. Mastomys, a rodent animal model, was found to be equally good for comparative evaluation of methemoglobin toxicity. Further, with the use of primaquine transdermal tape on the Mastomys model, a rise in methemoglobin occurred with increase in time. In conclusion, the study presents simple, economical, less time-consuming methods for the evaluation of methemoglobin toxicity, in vitro and in vivo, without employing the conventional Beagle dog model.

Administration, Cutaneous↗
PubMed1999

In vitro and in vivo wound healing activity of asiaticoside isolated from Centella asiatica.

The activity of asiaticoside, isolated from Centella asiatica, has been studied in normal as well as delayed-type wound healing. In guinea pig punch wounds topical applications of 0.2% solution of asiaticoside produced 56% increase in hydroxyproline, 57% increase in tensile strength, increased collagen content and better epithelisation. In streptozotocin diabetic rats, where healing is delayed, topical application of 0.4% solution of asiaticoside over punch wounds increased hydroxyproline content, tensile strength, collagen content and epithelisation thereby facilitating the healing. Asiaticoside was active by the oral route also at 1 mg/kg dose in the guinea pig punch wound model. It promoted angiogenesis in the chick chorioallantoic membrane model at 40 microg/disk concentration. These results indicate that asiaticoside exhibits significant wound healing activity in normal as well as delayed healing models and is the main active constituent of Centella asiatica.

Administration, Oral↗
PubMed1999

A time course study for the development of an immunocompromised wound model, using hydrocortisone.

Although wound healing is essentially a physiologic process, some chronic wounds exhibit considerable delay in healing. Often these do not heal perfectly in individuals with low immune profiles. Thus, the present study was undertaken to develop an excision wound model in the immunocompromised state induced by pretreatment with hydrocortisone (HC) 40 mg/kg intramuscularly in male rats. Wounds of 8-mm diameter were made on the preshaved dorsal surface of rats using an Acuderm biopsy punch, following pretreatment with HC. After 14 days HC-treated animals exhibited atrophy of spleen and adrenal glands and a significant reduction of circulating lymphocytes and increase in neutrophils; these changes are indicative of immunosuppressive state of animals. The cell proliferation was significantly affected as shown by decreases in DNA (23%) and protein (11%). Furthermore, there were also significant reductions in tensile strength (37%) and hydroxyproline (33%) contents. These results were further supported by lack of contraction of wound edges. It is concluded that animals primed with HC 1 week prior to wounding developed prolonged immunosuppression, which significantly impaired the wound healing as compared with other groups. Thus, this can be experimentally employed as an immunocompromised wound model for evaluating compounds as novel wound healers suitable for immunocompromised subjects.

Adrenal Glands↗
PubMed1996

In vitro percutaneous absorption of verapamil.

The in vitro percutaneous absorption of verapamil hydrochloride (VHCl) was investigated in order to assess its feasibility for transdermal development. The experiments were carried across mice and guinea pig skins using Keshary-Chien diffusion cell. The values of diffusion rate (J) and permeability coefficient (Kp) across guinea pig skin were lowered as compared to mouse skin. Increased drug concentration in donor compartment increased value of J but decreased value of Kp. Under similar conditions, values of J and Kp were lowered for dorsal skin as compared to abdominal skin, both for mice and guinea pig. The results indicate that verapamil can be administered transdermally.

Administration, Cutaneous↗
PubMed1993

In vitro transdermal delivery of atenolol using mouse and guinea pig.

In vitro percutaneous absorption of atenolol was done in order to assess its feasibility for transdermal development across mouse and guinea pig skins using Keshary-Chien type of diffusion cell. Values of diffusion rate (J) and permeability coefficient (Kp) across guinea pig skin were lowered as compared to those in mouse skin. When the concentration of drug in donor compartment was increased a decrease in Kp and increase in J value were observed with both the skins. Under the same conditions, values of J and Kp were lowered for dorsal skin compared to abdominal skin both for mouse and guinea pig. The results suggest that atenolol can be pursued further for transdermal system development.

Administration, Cutaneous↗
PubMed1975

Intra-abdominal symptoms arising from spinal osteophytes.

A case of abdominal pain caused by irritation of a segment of jejunum and another due to irritation of the ureter are reported. In both cases the cause of the irritation was established to be osteophytic growth from the 4th lumbar vertebra. After its excision the symptoms disappeared in both cases. To the best of our knowledge, osteophytes have not been reported before to be the cause of intestinal and ureteric pain, and its is therefore urged that in cases of intractable pain these must be considered as a possible cause.

Abdomen↗
PubMedDate not supplied

Spontaneous choledocoduodenal fistula--due to chronic duodenal ulcer.

A case of spontaneous choledocoduodenal fistula due to penetrating posterior duodenal ulcer is reported. The only presenting symptoms were pain and vomiting. There was no fever or recurrent jaundice which is usually expected in such a condition. The radiological findings included barium and air in the biliary tract. Biliary fistula are not uncommon. Although external biliary fistulae are seldom seen in present times, internal biliary fistulae are not a rare entity. Internal biliary fistulae are either spontaneous or due to operations on biliary tract. The common causes for spontaneous internal biliary fistula includes cholelithiasis, peptic ulceration and malignant neoplasm (Shiu) 1967. In a study of 819 cases by Waggoner and Le Mone (1949) 51% of such fistulae were cholecystoduodenal, 21% cholecystocolic, 19% choledocoduodenal, while the rest were choledocogastric and cholecystocholedocal. Most common cause for spontaneous choledocoduodenal fistula is due to gall stones, but, rarely posterior penetrating duodenal ulcer may also cause this condition. The following report concerns a spontaneous biliary fistula of the choledocoduodenal type, due to chronic duodenal ulcer.

Biliary Fistula↗