Search PubMed⌕ Search

Biomedical subjects

A Puri

Publications and source records attributed to A Puri.

85 records · Page 5Linked to original sources
PubMed1988

Activation of vesicular stomatitis virus fusion with cells by pretreatment at low pH.

Fusion of vesicular stomatitis virus (VSV) with Vero cells was measured after exposure of the virus to low pH under a variety of experimental conditions. The method of relief of fluorescence self-quenching of the probe octadecylrhodamine was used to monitor fusion. Incubation of the virus at pH 5.5 prior to binding to cells led to significant enhancement of fusion at the plasma membrane, whereas fusion via the endocytic pathway was inhibited. Fusion of pH 5.5-pretreated VSV showed a similar pH threshold for fusion as nontreated virus, and it was blocked by antibody to VSV G protein. Activation of VSV by pretreatment at low pH was only slightly dependent on temperature. In contrast, when VSV was first bound to target cells and subsequently exposed at 4 degrees C to the low pH, activation of the fusion process did not occur. The pH 5.5-mediated activation of VSV could be reversed by returning the pH to neutral in the absence of target membranes. The low pH pretreatment also led to aggregation of virus; large aggregates could be pelleted by low speed centrifugation and only the effects of the supernatant, which consist of single virions and/or microaggregates, were considered. The data were analyzed in the framework of an allosteric model according to which viral spike glycoproteins undergo a pH-dependent conformational transition to an active (fusion-competent) state. Based on that analysis we conclude that the conformational transition to the active state is rate-limiting for fusion and that the viral spike glycoproteins are fusion-competent only in their protonated form.

Allosteric Regulation↗
PubMed1986

Protection of mice against Plasmodium berghei infection by a tuftsin derivative.

In Plasmodium berghei infections, the mortality rate and parasitaemias were significantly reduced and the mean survival time was considerably enhanced by pretreating the animals with a tuftsin derivative, Thr-Lys-Pro-ARg-NH-(CH2)2-NHCOC15H31. This effect of the modified tuftsin was further increased upon its incorporation in the liposome bilayer. These results indicate that tuftsin and its derivatives may prove useful in enhancing nonspecific host resistance against protozoan infections.

Animals↗
PubMed1984

Comparative chromatography of hypothalamic corticotrophin-releasing factors.

Extracts of rat stalk-median eminences were chromatographed on Sephadex G-50 and BioGel P2. Effluent fractions were monitored for corticotrophin-releasing factor (CRF) bioactivity, using the perfused isolated pituitary cell column bioassay, and radioimmunoassay for CRF-41, AVP, oxytocin, neurophysin, adrenocorticotrophic hormone (ACTH) and luteinizing hormone-releasing hormone (LHRH). Porcine hypothalami were also chromatographed on Sephadex G-50. Our results suggest that vasopressin and a peptide in the rat related to synthetic ovine CRF are two components of the hypothalamic CRF complex which potentiate each other at the corticotrope to release ACTH. However, these two substances alone do not appear to be wholly responsible for CRF bioactivity of hypothalamic stalk-median eminence extracts and other CRFs may yet be found.

Animals↗
PubMed1984

Involvement of rat corticotrophin-releasing factor-41-related peptide and vasopressin in adrenocorticotrophin-releasing activity from superfused rat hypothalami in vitro.

Superfused rat hypothalamic pieces stimulated with a high K+ medium released corticotrophin-releasing factor (CRF) as detected in the rat isolated anterior pituitary cell column bioassay. This activity has components related to ovine CRF-41 (oCRF-41) and vasopressin as assessed by the effects of specific antisera on the ACTH-releasing activity of the hypothalamic column effluent. Release of immunoactive vasopressin paralleled that of CRF bioactivity. Immunoactive oCRF-41 could not be detected, as it is likely to be below the sensitivity of present radioimmunoassays.

Adrenocorticotropic Hormone↗
PubMedDate not supplied

Gastroschisis and omphalocele.

The survival rate of patients with abdominal wall defects has gradually improved with the advances in the investigation and treatment modalities. The present paper reviews the results of various treatment modalities and also analyses the long term results in these patients. A meta-analysis was performed via a medline search of English written clinical studies containing the text words "abdominal wall defects", gastroschisis and 'omphalocele or exomphalos" from 1953 to 1998. The present consensus on operative management of abdominal wall defect is to provide primary closure, if it can be achieved without haemodynamic or respiratory compromise. Patients with primary closure on analysis were found to have better survival rates, reduced risk of sepsis and overall, a shorter hospital stay. However, resumptions of oral feeds, duration of total parenteral nutrition (usually lasting 10-15 days) and ventilatory support required postoperatively did not significantly differ in the primary and silo technique. Long term outcome of these patients is generally good, but they have high incidence of GER (40-50%) for which they should be on regular follow up.

Digestive System Surgical Procedures↗
PubMedDate not supplied

Macrophage migration as an index of immune status.

Peritoneal macrophages from mice and guinea pigs pretreated with Freund's complete adjuvant (FCA) or any other immunostimulant when packed in a glass capillary and placed in a migration chamber migrated to a larger area than macrophages from normal untreated animals. The extent of migration could be correlated with the dose of FCA and the period of treatment. Under optimum conditions the ratio between the areas of migration of macrophages from FCA-treated animals and of macrophages from untreated animals was above 3.0. A close correlation was observed between macrophage migration and delayed type hypersensitivity (DTH) response in animals sensitized with ovalbumin or sheep red blood cells. The macrophages of immunostimulant-treated animals had relatively higher phagocytic activity. The macrophage migration index (MMI) appears to be a close correlate of macrophage activation and possibly also of the status of cell mediated immune response.

Animals↗
PubMedDate not supplied

Coexisting chondroblastoma and osteochondroma: a case report.

The coexistence of two different types of benign cartilaginous tumours of bone in the same patient has not been reported in literature. We report a case in which a sixteen-year-old male had a benign chondroblastoma of the proximal left humerus and an osteochondroma of the distal left femur. Both originated at the same time and had a progressive increase in size with growth.

Adolescent↗
PubMedDate not supplied

Cyst of ectopic (choristomatous) lacrimal gland.

A rare case of cyst of an ectopic lacrimal gland in the bulbar conjunctiva is reported in a 40 year-old-man. The clinical presentation histopathology, differential diagnosis and treatment of this choristomatous lacrimal ductal cyst (Group IV according to Bullock's classification) is described.

Adult↗