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M Buckingham

Publications and source records attributed to M Buckingham.

98 records · Page 6Linked to original sources

Length of the polyadenylated sequence in cytoplasmic ribonucleic acid isolated from fetal calf myoblasts differentiating in vitro.

Poly(adenylic acid) [poly(A)] containing cytoplasmic ribonucleic acid (RNA) in differentiating fetal calf myoblasts cultivated in vitro was examined by hybridization with radioactive poly(uridylic acid). The size distribution of the poly(A)-containing RNA after sucrose-gradient centrifugation was similar in cells before and after differentiation. There was no apparent correlation between the length of the poly(A) segment and the change in stability of messenger RNA which occurs on differentiation, nor with the polysomal or nonpolysomal localization of the RNA in the cytoplasm. The average length of the poly(A) segments in cytoplasmic RNA in the steady state was found to be dependent on the size of the RNA: the longer the RNA, the longer the average length of the poly(A) sequence. In contrast, in pulse-labeled RNa, the length of poly(A) is similar in all size classes of RNa.

Animals↗

Muscle coding sequences and their regulation during myogenesis: cloning of muscle actin cDNA probes.

For a number of years our group has been mainly interested in the regulation of muscle gene expression during myogenesis. Using primary cultures and cell lines we have tried to find out whether the coding sequences for muscle proteins are already present in an unexpressed form or if there is a transcriptional switch at the onset of differentiation. Metabolic studies on pulse-labelled RNA, together with translation and molecular hybridization experiments have given a certain number of indications. More recently the development of genetic engineering techniques has made it possible to answer these questions directly with probes which are complementary to specific muscle coding sequences. We have identified a plasmid which contains a coding sequence for muscle actin. Other recombinant plasmids are being characterized. Such plasmids, used as probes, will permit us to study the organization and expression of the genes coding for the contractile proteins in muscle cells.

Actins↗

Race as a risk factor in cadaver kidney transplantation.

Recipients of 93 first-cadaver kidney transplants were studied for the effect of recipient and donor race on graft and patient survival. Both graft and patient survival were lower for black recipients than for whites. The difference was not explained by racial mismatch between donor and recipient. Black recipients had more rejection episodes and more instances of bacterial pneumonia. Pretransplant splenectomy reduced the likelihood of rejection episodes for black recipients and increased their rate of graft survival.

Adult↗

Gastro-intestinal absorption and transplacental transfer of amoxycillin during labour and the influence of metoclopramide.

The absorption of amoxycillin from the gastro-intestinal tract, with or without oral metoclopramide, has been evaluated. Levels of amoxycillin in the maternal blood and liquor prior to the induction of labour were of a therapeutic level against many organisms. However, absorption during labour, as reflected by maternal blood levels at delivery and cord blood levels, suggests that amoxycillin is poorly absorbed and may not reach adequate therapeutic levels in the fetus. Oral metoclopramide did not improve the absorption of amoxycillin. Should a parenteral form of amoxycillin become available, a similar study of blood and liquor levels may indicate that, like ampicillin, intramuscular administration is required for adequate therapeutic use at this stage of pregnancy. Until an oral formulation of an appropriate antibiotic is available which gives rapid absorption may and a sustained level of the chemotherapeutic agent in this situation, parenteral administration of an appropriate antibiotic remains mandatory.

Amniotic Fluid↗

Investigation of genetic linkage between myosin and actin genes using an interspecific mouse back-cross.

The introduction of cloned probes to follow the segregation of DNA restriction fragment length polymorphisms (RFLPs) has led to a revival of mendelian genetics in attempts to map the human genome. In the mouse, however, it has often proved difficult to detect an RFLP with a DNA probe between different inbred strains of the laboratory mouse. To circumvent this problem, we have used two species, Mus musculus domesticus and Mus spretus which interact as sympatric species but can be interbred under laboratory conditions. Because of the relative evolutionary distance between these species, they exhibit polymorphism at many more loci than do different strains of the usual M. m. domesticus laboratory mouse. This is also observed at the DNA level when the sizes of restriction fragments encoding a specific gene are compared. We have used these RFLPs between M. m. domesticus and M. spretus to follow the segregation of genes encoding different isoforms of myosin alkali light chains in the backcross progeny between these species and to compare this with that of other contractile protein genes. No linkage between these genes was observed.

Actins↗