PubMed Health⌕ Search

Biomedical subjects

M Petric

Publications and source records attributed to M Petric.

121 records · Page 7Linked to original sources
PubMed1977

Viruses associated with acute gastroenteritis in young children.

Conventional virologic investigations generally failed to implicate viruses as a cause of acute gastroenteritis in young children. When negative-contrast stain electron microscopy was used for the examination of stool samples from affected patients, several candidate etiologic agents were discovered. Rotavirus (otherwise known as orbivirus, reo-like agent, and infantile gastroenteritis virus) emerged as an important causative agent. In a considerable number of patients, however, no causative agent was identified. Several other candidate etiologic viruses now "stand in the wings" awaiting additional evidence as to their role in the pathogenesis of acute gastroenteritis. In a study period of 12 months, 669 patients were found to be shedding virus in association with symptoms of diarrhea, vomiting, and temperature elevation. Approximately one third of these patients acquired their infection in hospital.

Acute Disease↗
PubMed1977

Solid-phase radioimmunoassay for the detection of rotavirus.

A solid-phase radioimmunoassay method has been developed for the detection of rotavirus in the form of a purified antigen and in stool. The parameters of the radioimmunoassay were examined and optimized to give high sensitivity and same-day results. Compared with electron microscopy, the assay is up to 10 times as sensitive for detection of the virus in stool and up to 128 times as sensitive for detection of a purified virus antigen. In a field study on stool specimens it was at least as efficient as electron microscopy.

Antibodies, Viral↗
PubMed1977

Human rotavirus enteritis induced in conventional piglets. Intestinal structure and transport.

To better understand the pathogenesis of infantile viral gastroenteritis, we studied Na+ and Cl- fluxes in vitro in short-circuited jejunal epithelium from 8-10-day-old piglets after infection with a standard dose of human rotavirus given via nasogastric tube. 11 infected piglets, all of whom became ill, were compared with 9 uninfected, healthy litter-mates. When killed 72 h after infection, intestinal villi were shorter and crypts deeper (P less than 0.025) in duodenum, upper jejunum, and mid-small intestine, but not ileum in infected piglets. Virus antigen was seen by fluorescence microscopy in occasional jejunal villus tip cells in only four infected piglets and no controls at 72 h. Net Na+ and Cl- fluxes did not differ from noninfected litter-mate controls under basal conditions, but response to glucose was blunted in infected piglets (P less than 0.001). Theophylline stimulated net Cl- secretion in both infected and control animals, and cyclic AMP concentration in isolated jejunal villus enterocytes did not differ significantly. In isolated jejunal villus enterocytes of infected piglets, thymidine kinase activity increased (P less than 0.001), and sucrase activity decreased (P less than 0.001). We conclude that in this invasive enteritis caused by a major human viral pathogen, glucose-coupled Na+ transport is impaired in the jejunum at a time when the villus epithelium shows enzyme characteristics of crypt epithelium, and when little or no virus is present. These findings are identical to those occurring in an invasive coronavirus enteritis of piglets but differ markedly from those seen with enterotoxigenic diarrhea.

Animals↗
PubMed1976

Counter-immunoelectro-osmophoresis for the detection of infantile gastroenteritis virus (orbi-group) antigen and antibody.

A moderatley sensitive, rapid, and economical test scheme for the detection of infantile gastroenteritis virus (IGV) in stool or antibody in serum has been developed and evaluated. The test scheme with minor modifications was an adaptation of a counter-immunoelectro-osmophoresis system we once used for the detection of hepatitis B antigen. Large numbers of stool samples may be screened during half a working day for the presence of IGV using reference antiserum to IGV prepared in guinea-pigs. Serological studies of a diagnostic but not epidemiological nature may also be performed with equal facility by this same test scheme using highly purified IGV antigen derived from stool.

Adolescent↗
PubMed1976

Indirect microhemagglutination test for varicella--zoster antibody determination.

An indirect microhemagglutination assay (IHA) was devised because of a need to provide an alternative test to complement fixation (CF) for varicella-zoster (V-Z) antibody determination. Human erythrocytes were sequentially treated with 2% glutaraldehyde, 0.04% tannic acid, and 2% pyruvic aldehyde then exposed to sonicated V-Z infected cells. This same tanning procedure was suitable for herpes simplex and Epstein-Barr virus antigen attachment but unsatisfactory for several non-herpes-group viruses. V-Z antibody titres determined by IHA were generally 2 to 6 times higher than CF titres. Cross-reaction with herpes simplex antibody was minimal.

Adult↗
PubMed1976

Studies on the particles of infantile gastroenteritis virus (orbivirus group).

Isopycnic centrifugation of infantile gastroenteritis virus (orbivirus group) in a CsCl gradient produced up to four bands at densities 1.38, 1.36, 1.30 and 1.28 g/ml. The particles in the bands had sedimentation coefficients of 380-400S, 520-530S, 270-280S and 320-330S, respectively. Whereas the 1.38 and 1.36 g/ml particles contained RNA, the 1.30 and 1.28 g/ml particles lacked RNA. Upon heating at 37 degrees, the 1.36 g/ml particles broke down into particles of higher and lower density.

Centrifugation, Density Gradient↗
PubMed1975

Propagation of infantile gastroenteritis virus (orbi-group) in conventional and germfree piglets.

Infantile gastroenteritis virus (orbi-group) recovered from stools of infants with acute nonbacterial gastroenteritis was administered per os to germfree and conventional piglets. Virus was found subsequently in stools and in the mucosal epithelial cells of the small intestine of these animals. Some animals developed diarrhea. Added proof of orbivirus replication was obtained through the use of tritiated uridine injections and the recovery of labeled virus in gut contents at the time of autopsy. Serological conversion was demonstrated in infected germfree piglets.

Animals↗
PubMed1975

California encephalitis virus development in mosquitoes as revealed by transmission studies, immunoperoxidase staining, and electron microscopy.

Isolates of the snowshoe hare subtype of California encephalitis (CE) virus from Yukon mosquitoes during 1972 and 1973 were transmitted by bites of Aedes aegypti mosquitoes after 4 to 5 weeks of extrinsic incubation at 55 degrees F after intrathoracic injection, and the 1973 strain was transmitted after mosquitoes were fed virus and held for 3 to 4 weeks at 75 degrees F. Antigen of a 1971 isolate of CE virus (Marsh Lake 23) was detected in salivary glands of infected mosquitoes by the immunoperoxidase technique, using highly purified antiserum before and after conjugation with horseradish peroxidase, plus the use of orthotolidine as a substitute for benzidine. enveloped virions 45 nm in diameter were observed in thin sections of salivary glands of Culiseta inornata mosquitoes 59 days after intrathoracic injection with the 1971 isolate, afterincubation at 55 degrees F.

Aedes↗
PubMedDate not supplied

Immunoelectron microscopic identification of human parvovirus B19.

A mildly macerated, hydropic fetus was delivered spontaneously at 25 weeks gestation by a multigravidous black mother. At autopsy, gross and microscopic evidence suggested fetal anemia, and excessive extramedullary erythroblastosis was present generally. Erythroid precursor cells in the pulmonary capillary circulation contained eosinophilic nuclear inclusions consistent with human parvovirus B19 infection. Transmission electron microscopy on osmicated Epon lung sections showed lucent, granular chromatin corresponding to the inclusions. In rare foci only these sections contained paracrystalline arrays of 20-nm virions. In the same cells, similar virions were seen within the cytoplasm, both randomly distributed and in paracrystalline aggregates. Postembedding immunoelectron microscopy, done on formalin-fixed lung embedded in a hydrophilic resin, showed positive labelling over the nuclear inclusions, and also localized the viral capsid antigen to cytoplasmic virion aggregates. The nuclear aggregates suggest that the virus would reach the circulation after cell lysis whereas those in cytoplasm suggest that parvovirus also may be excreted from infected cells before they lyse.

Adult↗