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Biomedical subjects

A B Murray

Publications and source records attributed to A B Murray.

At least 19 recordsLinked to original sources
PubMed1992

Retrovirus-like particles from the human T47D cell line are related to mouse mammary tumour virus and are of human endogenous origin.

Retrovirus-like particles were secreted in a steroid-dependent manner by the human mammary carcinoma cell line T47D. The particles exhibited typical retroviral properties such as their electron microscopic appearance (95 nm in diameter) and occasional budding, sedimentation at 1.14 g/ml, reverse transcriptase activity and genomic RNA. The T47D particles were related to mouse mammary tumour virus (MMTV) as shown by their ultrastructural appearance (B type-like eccentric dense cores and budding), Mg2+ dependence of the reverse transcriptase activity; immunological reactivity with MMTV-directed antibodies (revealing proteins of 63K, 52K, 26K and 18K), and hybridization of particle RNA with MMTV DNA under stringent conditions. Purified particles were able to incorporate deoxynucleoside triphosphates in the absence of an exogenous primer and template, thus indicating the existence of a complete and biochemically functional reverse transcription apparatus (reverse transcriptase, RNA and primer) and the ability to direct endogenous cDNA synthesis. Labelled particle cDNA hybridized strongly to human genomic DNA but not to mouse and cat DNA, thus indicating the human origin of the T47D particles. Furthermore all human DNAs, hybridized with the labelled particle cDNA, showed a uniform hybridization pattern of restriction fragments, indicating the endogenous origin and distribution of the proviral particle DNA in the human genome.

Adenocarcinoma↗
PubMed1992

Sexual dimorphism of the kidney in the NMRI mouse as shown by Dolichos biflorus agglutinin labelling.

The histological affinity pattern of Dolichos biflorus agglutinin (DBA) in kidneys from mice (NMRI, Balb/c, CBA) and rats (Wistar) fixed by perfusion with formalin, Bouin, or HgCl2 was investigated with a horseradish peroxidase conjugate. The animals were examined from fetal stage to adulthood. Adult female NMRI mice exhibited constant DBA labelling, with DBA binding to cells of the proximal and collecting tubules. Moreover the vascular endothelium of the renal papilla was found to be DBA-positive in 50% of adult female animals. In contrast, there was only very little DBA binding in the kidneys of male adult NMRI mice. There was no sexual dimorphism in lectin labelling in kidneys from other strains of mice or from rats.

Animals↗
PubMed1992

Effect of passive smoking on asthmatic children who have and who have not had atopic dermatitis.

We studied 240 children with asthma who were themselves nonsmokers and had been referred consecutively to our clinic. They were aged 6 to 17 years. The severity of asthma was assessed by symptom score, by spirometry, and, in those who could perform the test reliably, by histamine bronchial challenge test. Those who reported having had a chronic or chronically relapsing itchy rash in characteristic locations were recorded as having had atopic dermatitis. Multiple analysis of variance revealed that children whose mothers smoked had significantly more severe asthma (p less than 0.001) but that atopic dermatitis had no apparent effect on the severity of asthma, either in its main effect (p = 0.71) or in its interaction with maternal smoking (p = 0.66). Although our previous study indicates that smoking mothers' children are more likely to develop asthma if they have had atopic dermatitis than if they have not, the severity of asthma does not appear to be associated with a history of atopic dermatitis. In smoking mothers' children the asthma was just as severe in those who had not had atopic dermatitis as in those who had.

Adolescent↗
PubMed1991

Intradermal vaccination against hepatitis B in a group of medical students.

A prospective study of a low-dose (one-tenth) intradermal regimen using recombinant hepatitis B vaccine was undertaken during two consecutive years in 4th-year medical students. Eighty-one per cent of the vaccinees (123/152) sero-converted with anti-HBs levels of greater than 10 IU/l. The lower titre of hepatitis B surface antibodies compared with published studies on intramuscular immunisation, together with a sero-conversion rate of only 81%, makes the intradermal method, in our opinion, a suboptimal form of hepatitis B immunisation.

Hepatitis B Antibodies↗
PubMed1991

Bone tumor induction after incorporation of short-lived radionuclides.

Temporally-limited internal irradiation after incorporation of short-lived bone-seeking radionuclides is a useful experimental tool for the investigation of extrinsic and intrinsic factors which modify the dose dependence of bone tumor risk. Here we describe some of the results obtained in experiments with female mice (mainly NMRI). The future aim of such experiments should be the prediction of risk of late effects using early molecular-biological changes. Molecular-biological descriptions in our model are at present very limited.

Animals↗
PubMed1991

In situ embedding of cell monolayers cultured on plastic surfaces for electron microscopy.

Various procedures suitable for routine in situ embedding of cell monolayers were tested including: (1) the use of different Epon substitutes, (2) the use of different types of plasticware obtained from different sources, and (3) different methods of preparing capsules for sectioning. Different resins reacted differently with different plastics and type of preparation. Merck Epon substitute bound to most of the plastics tested. Ladd Epon substitute released cleanly from all plastics tested when a suitable method of preparation was used. The results show that for routine embedding of cell monolayers it is necessary to select an appropriate Epon substitute and method of preparation of capsules for the type of plasticware used. A routine method is described, with various alternative steps which can be applied when particular difficulties are encountered.

Animals↗
PubMed1979

The seasonal variation in a population of house dust mites in a North American city.

Mattress dust collected at monthly intervals for 2 1/2 yr was examined for mites. Both Dermatophagoides pteronyssinus and D. farinae were found. There was a significant association between the presence of live mites and the relative humidity (RH): Live mites were seen only when the RH had been greater than or equal to 50% for at least part of every day during the month of collection. There was a seasonal variation in that live mites were found only in the warmer months and not in the winter. However, the peak in the mite population was consistent neither for month nor for numbers: In 1977 a slight peak in mite numbers occurred in October, while in 1978 the peak was higher and occurred in July. Use of data from previously published studies to preduct mite levels may therefore be misleading.

Animals↗
PubMed1979

Anorexia of infection as a mechanism of host defense.

The role of anorexia of infection as a mechanism of host defense was studied by force-feeding infected mice to a normal energy intake. Their mortality and survival times were then compared with those of infected mice feeding ad libitum. Mortality was increased and survival time shortened in force fed animals. Our observations suggest that anorexia, by reducing energy intake, has a significant role in the early defense of the host.

Animals↗
PubMed1979

Three-dimensional reconstruction of the chromatin bodies in the nuclei of mature erythrocytes from the newt Triturus cristatus: the number of nuclear envelope-attachment sites.

The arrangement of the chromatin bodies in the interphase nuclei of 6 erythrocytes has been investigated by means of 3-dimensional reconstruction from electron micrographs of serial sections. When the borders of chromatin bodies are marked on the surface of each model, discrete areas of chromatin in contact with the nuclear envelope are revealed. The number of these areas in approximately equal to the number of chromosomes in the diploid set. The data suggest that each chromatin body corresponds to a condensed interphase chromosome and that each chromosome is attached to one discrete site on the nuclear envelope. The data are insufficient to show whether or not the condensed chromosomes are arranged in any orderly pattern in these nuclei.

Animals↗
PubMed1978

The adverse effect of iron repletion on the course of certain infections.

The incidence of infections was studied in 137 iron-deficient Somali nomads, 67 of whom were treated with placebo and 71 with iron. Seven episodes of infection occurred in the placebo group and 36 in the group treated with iron; these 36 episodes included activation of pre-existing malaria, brucellosis, and tuberculosis. This difference suggested that host defence against these infections was better during iron deficiency than during iron repletion. Iron deficiency among Somali nomads may be part of an ecological compromise, permitting optimum co-survival of host and infecting agent.

Adolescent↗
PubMed1978

Serum cholesterol, triglycerides and heart disease of nomadic and sedentary tribesmen consuming isoenergetic diets of high and low fat content.

1. The effects were examined of two approximately isoenergetic diets differing widely in saturated fat content on the levels of serum cholesterol and triglycerides of nomads and non-nomads in eastern Niger. Each person was also examined for clinical and electrocardiographic evidence of heart disease. 2. No significant differences could be found between serum cholesterol and triglyceride levels of 297 Anagamba nomad men consuming 73% energy as fat and 303 Kanouri sedentary men consuming 9% energy as fat. 3. Rheumatic heart disease was common in nomads and four possible cases of ischaemic heart disease were found in sedentary men only.

Adolescent↗
PubMed1978

The effect of iron status of Nigerien mothers on that of their infants at birth and 6 months, and on the concentration of Fe in breast milk.

1. Within the limits of this study, neither maternal iron deficiency nor Fe-overload as measured at term appeared to affect the complement of Fe received by the foetus. 2. Infants feeding entirely on breast milk appeared to have normal Fe status 6 months postpartum regardless of the Fe status of the mother. 3. No relationship could be demonstrated between the Fe content of breast milk and the Fe status of the mother.

Anemia, Hypochromic↗
PubMed1978

Diet and cerebral malaria: the effect of famine and refeeding.

In an outbreak of Plasmodium falciparum malaria following refeeding after famine cerebral malaria was restricted to children eating grain. Nomad children consuming a predominantly milk diet were free of this complication despite an equivalent incidence of uncomplicated malaria. Freedom of nomads from cerebral complications may be due to inhibition by the milk diet of rapid division of the parasite combined with delayed recovery after famine of T cell function.

Animals↗
PubMed1977

Starvation suppression and refeeding activation of infection. An ecological necessity?

The hypothesis is advanced that starvation suppresses and refeeding activates certain infections as an essential part of an ecological balance between man, his animals, and his environment. During famine, then, man fails to thrive, but his ultimate extinction is prevented in part by the parallel decline in fecundity of his "micropredators". In times of plenty the parallel increase in the same predators is a check against his excessive multiplication.

Adult↗