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Biomedical subjects

R Burrows

Publications and source records attributed to R Burrows.

At least 73 records · Page 4Linked to original sources
PubMed1987

Cholesterol synthesis in rat liver peroxisomes. Conversion of mevalonic acid to cholesterol.

The key regulatory enzyme of cholesterol, dolichol, and isopentenyl adenosine biosynthesis, 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMG-CoA reductase) is a 97-kilodalton transmembrane glycoprotein which was believed until recently to reside exclusively in the endoplasmic reticulum of mammalian cells. However, several recent publications have shown that the enzyme in liver cells is present not only in the endoplasmic reticulum but also within peroxisomes. In an effort to clarify the role of peroxisomal HMG-CoA reductase, highly purified (95%) rat liver peroxisomes from cholestyramine-treated rats were incubated with RS-[2-14C]mevalonic acid plus cytosolic proteins and then tested for the presence of newly synthesized cholesterol. For comparison, highly purified microsomes from the same liver preparation were incubated at several protein concentrations under the same conditions. A three-step procedure was employed to resolve the newly synthesized cholesterol from the complex mixture of sterol intermediates in cholesterol biosynthesis. After termination of the reaction and addition of a [3H]cholesterol standard, the incubation products were extracted and separated by thin layer chromatography into a number of fractions. The fraction containing C-27 sterols was further resolved by reverse-phase high pressure liquid chromatography. After acetylation, the products were then separated by silicic acid high pressure liquid chromatography. Confirmation of the identity of newly synthesized cholesterol was obtained by recrystallization with added non-radioactive cholestenyl acetate standard. The results indicate that highly purified rat liver peroxisomes are able to convert mevalonic acid to cholesterol in the presence of cytosolic fraction in vitro. An abstract of these results has been published (Krisans, S. K., Thompson, S. L., Burrows, R., and Laub, R. J. (1986) J. Cell Biol. 103, 525 (abstr.).

Animals↗
PubMed1987

Sociocultural characteristics of pregnant and nonpregnant adolescents of low socioeconomic status: a comparative study.

The objective of this study was to compare the sociocultural characteristics of pregnant adolescents of low SES with a nonpregnant adolescent group from the same area of Santiago, Chile. The sample was composed of 229 adolescents, 129 of whom were pregnant for the first time (group A), and 100 who were not pregnant (group B). Each pregnant girl was matched with a nonpregnant girl of the same age and from the same neighborhood. Several differences between the groups were found. Group A had less schooling, a lower level of aspirations, and tended to live in "the present." In addition, norms of behavior were more permissive, they did not practice any religion, and their peer group had more liberal attitudes. The importance of breaking these patterns in order to prevent adolescent pregnancy is discussed.

Adolescent↗
PubMed1987

Hemoglobin barts hydrops fetalis syndrome.

A 25 year old Vietnamese-Canadian pregnant woman was referred to our regional perinatal center at 31 weeks gestation after a routine ultrasound examination showing fetal ascites. A diagnosis of non-immune hydrops fetalis was made, and a Caesarean section was performed two days after hospital admission. An infant with Hb Barts hydrops fetalis was delivered who expired one hour after birth. alpha-Globin gene mapping of fetal DNA confirmed the diagnosis of homozygous alpha-thalassemia with deletion of all four alpha-globin genes. Both parents were shown to have alpha-thalassemia trait with deletion of both alpha-globin genes on one chromosome. This report further illustrates the need for a simple screening test for couples at risk of giving birth to infants with homozygous alpha-thalassemia. The availability of such a test would facilitate genetic counselling and prenatal diagnosis, thereby improving the quality of obstetrical care provided to these women at risk.

Adult↗
PubMed1985

Group therapy.

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Adult↗
PubMed1984

Trials of an inactivated equid herpesvirus 1 vaccine: challenge with a subtype 1 virus.

Vaccinated yearlings , two-year-old and in-foal pony mares with appropriate controls were exposed to aerosols of a subtype 1 virus one to two months after two or three vaccinations; all became infected. No obvious differences in the febrile responses, clinical signs and subsequent abortions were found between vaccinated and control mares. All vaccinated yearlings and two-year-old ponies developed a febrile respiratory disease but this was less severe than that suffered by the controls and the amounts and duration of virus shedding were reduced.

Abortion, Veterinary↗
PubMed1984

Development of an enzyme-linked immunosorbent assay (ELISA) for the detection of specific antibodies against an H7N7 and an H3N8 equine influenza virus.

This paper describes a solid-phase microtitre plate enzyme-linked immunosorbent assay (ELISA) for the detection of antibodies to equine influenza viruses. Using egg-grown influenza viruses as the antigens attached to the solid phase, cross-reactions were observed between an H7N7 equine virus (designated A1) and an H3N8 equine influenza virus (designated A2) when untreated antisera were tested. Absorption of antisera with egg-grown A/Porcine/Shope/1/33 influenza virus eliminated cross-reactive antibodies so that specific detection of anti-equine influenza A1 or A2 antibodies was possible. Examination of horse sera following vaccination with A1 and/or A2 isolates showed that antibodies were produced against antigen associated with egg allantoic fluid as well as against virus. Such antibodies were eliminated following the absorption of antisera with porcine influenza virus. Results using sera from horses with known vaccination histories confirmed that the ELISA preferentially detected antibodies homologous to the antigen attached to the solid phase and methods to evaluate the current serological state of individual horses by relating the titres of specific antibodies against equine influenza A1 and A2 isolates are shown. This ELISA provides a simple and rapid method of assessing specific antibodies from horse sera and offers advantages over the 'routine' HI and SRH assessments since it gives high precision, is economical of reagents and has the capacity to handle large numbers of serum samples.

Animals↗
PubMed1982

Antigenic properties of some equine influenza viruses.

The antigenic relationships between the haemagglutinins of five A/equine-1 viruses and between six A/equine-2 viruses were examined using post-infection ferret and immunized pony sera. Similar results were obtained with sera from both species for the A/equine-1 viruses and these confirmed minor antigenic differences between the prototype A/Prague 1/56 virus and viruses isolated in England in 1973 and 1977. Considerable antigenic differences were found between five of the A/equine-2 viruses, using ferret sera, but these differences were less evident using pony sera. The response of ponies to the inactivated viruses indicated that there was little need to change the virus strains used in the manufacture of commercial equine influenza vaccines.

Animals↗
PubMed1981

An outbreak of paresis in mares and geldings associated with equid herpesvirus 1.

An outbreak of paresis occurred on a small isolated stud farm in July 1980. Of the 42 horses on the stud, infection was confined to a group of nine in-foal mares and their foals and eight other horses which were either housed together at night or grazed adjacent pastures. Eight mares and two geldings developed ataxia or paresis and one mare died. Equid herpesvirus 1 was isolated from 17 animals and serological studies confirmed that 24 of 26 animals sampled had experienced infection.

Animals↗
PubMed1981

Field and laboratory studies of equine influenza viruses isolated in 1979.

Experimental ponies developed signs of disease four days after the intranasal instillation of A/England 1/79 equine influenza virus and virus was recovered from the nasopharynx from the second to the ninth day. No significant antigenic difference was found between the virus and the prototype A/Miami 1/63 virus, using post infection ferret and chicken sera and post vaccination pony sera. No antigenic differences were found between four viruses isolated between January and July 1979, although some differences were found in their ability to detect haemagglutination inhibiting antibody in convalescent horse sera.

Animals↗
PubMed1979

Noncalcified echinococcal liver cyst.

A large echinococcal cyst containing clear fluid was seen as a lucent defect within the liver on the plain radiograph. It had no fatty or calcific contents. No similar cases could be found in the literature.

Adult↗
PubMed1978

Case report: echinococcal cyst of the liver seen on computed tomography.

A case of a single, large noncalcified echinococcal cyst of the liver demonstrated by computed tomography (CT) and verified at surgery is presented. To our knowledge, no previous CT pictorial display of such a lesion has been reported in the literature. The cyst appears as a radiolucent, sharply demarcated lesion of water density.

Echinococcosis, Hepatic↗
PubMed1977

The outbreak of equine influenza in England: January 1976.

Equine influenza type 2 infections occurred in the Newmarket areas in January 1976. The disease did not spread to any extent and while this may have been due to recent vaccination it was found that not all vaccinated horses were fully protected. The virus involved showed some antigenic drift from the prototype strain A/equine/Miami/1/63 (Heq 2 Neq 2).

Animals↗