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Biomedical subjects

A Roberts

Publications and source records attributed to A Roberts.

At least 379 records · Page 21Linked to original sources
PubMed1976

Inbred mice and their hypbrids as an animal model for atherosclerosis research.

1. The inbred strain of mouse is a relatively inexpensive and easily controlled animal that produces consistent results within each of the P1, P2, F1, F2, B1 and B2 generations. 2. The mother and father exert an equal influence on the development of fatty deposits in the aortic sinus wall and on serum total cholesterol levels. 3. Different strains of inbred mice react to the high-fat, high-cholesterol diet in different ways. 4. The control mice of the CBA/J (P2) strain had significantly lower values of serum total cholesterol and size of the largest lesion at some weeks than the control mice of the C57BR/cdJ and F1, F2, B1 and B2 generations. 5. The experiments indicate a multifactorial (polygenic) system of inheritance.

Animals↗
PubMed1975

The uterine and cardiovascular effects of salbutamol and practolol during labour.

Intravenous salbutamol, a beta-adrenoceptor stimulant, given to nine patients in normal labour, with continous monitoring of uterine activity and of the maternal and fetal cardiovascular systems, was shown to decrease uterine activity significantly; maternal and fetal heart rates were significantly increased, and maternal systolic and diastolic arterial pressures were significantly decreased during the infusion, although no treatment had to be discontinued because of these effects. Apart from worsening of low back pain during the infusion in one patients, subjective side-effects were trival. With the salbutamol infusion continued at an effective maintenance rate, the carioselective beta-adrenoceptor blocking drug, practolol, given intravenously, reduced the maternal heart rate (although not significantly) but it did not alter the fetal heart rate; it also appeared to interfere transiently with the inhibiting action of salbutamol on uterine activity, but cerevical dilatation was arrested until the salbutamol infusion was discontinued. At least in five patients, labour remained suppressed until oxytoxin was infused intravenously.

Albuterol↗
PubMed1975

Aortic root dilatation and mitral valve prolapse in Marfan's syndrome: an ECHOCARDIOgraphic study.

Echocardiographic and phonocardiographic findings in 35 patients with Marfan's Syndrome and ten patients without Marfan's or other clinically apparent connective tissue disorders but with angiographic and echocardiographic evidence of mitral prolapse are reported and compared. Echocardiography revealed aortic root dilatation and/or mitral valve prolapse in 97% of the patients with Marfan's Syndrome. Aortic root dilatation was found in 60% of this group (74% of males, 33% of females) while mitral valve prolapse was found in 91% (87% of males, 100% of females). The incidence of aortic dilatation and mitral prolapse in patients with Marfan's syndrome was essentially equal in children and adults of the same sex. None of the nine adults or one child with mitral prolapse but without evidence of Marfan's Syndrome or other clinically apparent connective tissue disorder had aortic root enlargement. Ausculatory examination and phnocardiography revealed abnormalities in 54% of the patients with Marfan's Syndrome. Aortic regurgitation was found in 23% of this group (35% of males, 0% of females) while mitral regurgitation and/or mitral clicks were found in 46% (39% of males, 58% of females). Aortic regurgitation was much more frequent in adult males with Marfan's Syndrome (7/14, 50%) than male children (1/9, 11%), while the incidence of abnormal mitral sounds was essentially the same in adults (33% of males, 60% of females) and children (43% of males, 57% of females) of the same sex with Marfan's Syndrome. Abnormal mitral sounds were more frequent in patients without Marfan's who had mitral prolapse (90%) than in those with Marfan's (46%). It appears that cardiac abnormalities are a consistent manifestation of Marfan's Syndrome and that ultrasound is a more sensitive indicator of these abnormalities in such patients than ausculation or phonocardiography.

Adolescent↗
PubMed1975

Catabolism of human IgG in mice sensitized to various IgG fragments. Similarities to the catabolism of rheumatoid IgG in mice.

Whole body elimination studies of human serum IgG have showm that C57Bl miceare tolerant to this protein at low concentrations. The present study demonstrates that tolerance to this protein may be broken by presensitization of the mouse with the pepsin-derived fragments of human IgG (F(ab)2 and pFc), in marked contrast to the papain-derived fragments (Fab and Fc). Sensitization with F(ab)2 fragments induced a distinctive elimination pattern of the intact protein which was analogousto that observed in non-sensitized mice injected with serum IgG isolated from patients with rheumatoid arthritis. Since, by circular dichroism studies, we have previouslyimplicated a structural anomaly at or near the hinge region of the 'rheumatoid' IgGmolecule, our observations are discussed in relationship to a possible immune aetiologyfor rheumatoid arthritis.

Animals↗
PubMed1975

The distribution of non-synaptic intercellular junctions during neurone differentiation in the developing spinal cord of the clawed toad.

The distribution of intercellular junctions, other than synapses and their precursors, has been described in the developing spinal cord of Xenopus laevis between the neurula and free swimming tadpole stages. At the neurocoel, ventricular cells are joined in the apical contact zone by a sequence of junctions which usually has one or more intermediate junctions but also includes close appositions, gap junctions and desmosomes. This apical complex is more diverse than that reported in other vertebrate embryos and between ependymal cells in the adult central nervous system. Gap junctions are also found between ventricular cells and their processes near the external cord surface. However, no other special junctions occur in this location under the basement lamella which surrounds the cord. Punctate intermediate junctions are generally distributed between undifferentiated and differentiating cells and their processes but were not found in neuropil after stage 28. These results are discussed in relation to cell movements during neural differentiation, possible effects on the freedom of movement of ions and molecules through extracellular pathways in the emryo, and possible intercytoplasmic pathways via gap junctions which may be responsible for the physiologically observed electrical coupling between neural tube cells.

Animals↗
PubMed1975

The assessment of maternal nutrition.

The assessment of maternal nutrition is a very important task that should become a more integral part of clinical obstetrical care. It is not simple but neither is it overly complex for the practical office or clinic setting or personnel. This is especially critical for the groups at nutritional risk. Normal pregnancy physiology complicates the interpretation of traditional physical and laboratory techniques and, therefore, must be thoroughly understood. The dietician and/or nutritionist should be involved where available. The physician and nursing component of maternity care must, however, be increasingly aware of and involved with assessment techniques if maternity patients are to achieve adequate nutrition in practical clinical terms.

Diet↗