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Biomedical subjects

R Gillett

Publications and source records attributed to R Gillett.

30 records · Page 2Linked to original sources
PubMed1980

Scanning electron microscopic observations of the surface of the initial lesion in experimental streptococcal endocarditis in the rabbit.

The surfaces of vegetations in the first 24 h after initiation of experimental streptococcal endocarditis in rabbits were examined systematically using the scanning electron microscope (SEM). Most of the observed fields were occupied by amorphous material but with the SEM very small features of interest could be identified. Erythrocytes were more frequent before 6 h and leukocytes were rarely seen. Bacteria were significantly more frequent at 10/15 min and at 20 h. It is suggested that bacteria lodge on the vegetation surface following inoculation and that after a lag phase colonies are formed within the vegetation which reach the surface again at about 20 h.

Animals↗
PubMed1979

Light microscope and electron microscope alkaline phosphatase cytochemistry of rat bone marrow leukocytes.

An enzyme cytochemical method yielding an osmiophilic reaction product, visible at both the light and electron microscope levels, has been applied to the study of alkaline phosphatase in rat bone marrow cells. The enzyme is present in both eosinophils and, in much smaller amounts, in neutrophils. In both cases it is present on the plasma membrane, and in eosinophils intracellular aggregations of reaction product are also seen. The specific granules in both cell types fail to react and the enzyme is first detectable at the promyelocyte stage. Thus the enzyme is demonstrable before specific granule formation begins in the neutrophil, indicating that they are not a significant site of alkaline phosphatase activity in the rat.

Alkaline Phosphatase↗
PubMed1978

Differential leucocyte counts: a comparison of results using light and electron microscopy.

A method is described for handling leucocytes from an inflammatory peritoneal exudate prior to electron microscopy, which allows differential counts from ultra-thin sections to be made. The results of counts from ultrathin sections, viewed on the electron microscope, are compared with samples from the same cell populations prepared on a cytocentrifuge and counted by light microscopy. The results from several cell populations of widely different compositions show clearly that with suitable care taken over preparation and orientation, ultrathin sections can yield comparable differential counts to those obtained by standard light microscope procedures. Possible sources of error are discussed and the advantages of ultrastructural counting assessed. The method has a wide application wherever accurate differential counts are required from cell suspensions processed for electron microscopy.

Ascitic Fluid↗
PubMed1978

Ultrastructural localization of alkaline phosphatase in rat eosinophil leucocytes.

The ultrastructural localization of alkaline phosphatase in eosinophil leucocytes, obtained from experimentally-induced peritoneal exudates in rats, has been studied using an osmiophilic technique with 2-naphthylthiolphosphoryl dichloride as substrate, fast Blue BBN as diazonium salt and postosmication with 1% aqueous osmium tetroxide. With this method identical incubation procedures could be used for both light and electron microscope examination. Eosinophils were the only cells which contained alkaline phosphatase. The enzyme was predominantly associated with the outer surface of the plasma membrane, being present in much lower concentrations in cytoplasmic cisternae. Eosinophil granules only rarely showed reaction product. The plasma membrane location of alkaline phosphatase in eosinophil leucocytes is identical to that recently demonstrated in the human neutrophil.

Alkaline Phosphatase↗
PubMed1976

Rapid modification of the morphology of cell contact sites during the aggregation of limpet haemocytes.

Haemocytes suspended in the blood of the limpet Patella vulgata rapidly form microspikes and aggregate in response to withdrawal from the haemocoel. It has previously been suggested that the contacts between colliding cells in shaken suspension are stabilized by the rapid spreading of participant cells over each other's surfaces by a microspike-dependent process. In this communication we report that an electron-microscopic study of the contacts formed between cells in the early stages of aggregation suggests that intercellular contact elicits a rapid response from the organelles concerned with cell motility. This response leads to the rapid progression of each initial collision through 3 major categories of contact morphology, namely cell body/lamella, lamella/lamella and cell body/cell body. There is a concomitant increase in the area of mutually contacting surface between participating cells. On the basis of these results, a model is constructed for the participation of sub-surface components in the process of cellular aggregation. The sequence of development of contact found between aggregating cells is envisaged to be a consequence of cellular locomotory activities resembling those by which these cells spread on to a solid substrate. Included in this process is an element of intercellular recognition. It is suggested that the involvement of motile elements in cell aggregation is a general feature of aggregating cells. This would permit a re-interpretation of aggregation experiments which show specificity of cell adhesion, for total adhesive interactions between cells would depend not only on the adhesiveness per unit area of contacting cell surface but also on the extent or rate of formation of flat contact areas. The latter element could be regulated by a recognition system between contacting cells independently of the force per unit area which holds the 2 surfaces together.

Animals↗
PubMed1975

Distilled glutaraldehyde: its use in an improved fixation regime for cell suspensions.

A method is described for the sequential fixation of cell suspensions, suitable for use at room or culture temperatures. Though an adequate method for fixing cell suspensions does exist in the literature (Hirsch & Fedorko, 1968), it involves the use of a mixed glutaraldehyde-osmium tetroxide fixative. Since these two components inter-react, this method has many drawbacks. Previously described weaknesses of a sequential fixation regime (Hirsch & Fedorko, 1968; Jones, Yeh & Hirsch, 1972) with glutaraldehyde and osmium tetroxide have been overcome by the use of vacuum distilled glutaraldehyde as the primary fixative. The results, using a mixed glutaraldehyde-osmium tetroxide fixative and using the two components sequentially on a variety of cell types, are compared. The advantages of a sequential fixation made possible by the use of vacuum distilled glutaraldehyde rather than commercial glutaraldehyde are discussed.

Aldehydes↗
PubMed1973

The post-mortem diagnosis of influenzal infection by fluorescent IgG, IgA and IgM antibody studies on necropsy blood.

Necropsy blood from cases diagnosed as dying from influenza A was examined for specific antibody in the IgG, IgA and IgM fractions and a specific diagnosis of recent infection was made if either IgM or IgA antibody and low titres of IgG antibody were found. By these criteria a diagnostic rate of 77% was found in those cases from whom no virus was isolated. The use of infected cell monolayers grown on polytetrafluoroethylene-coated slides gave a simple method of carrying out these antibody assays, and the use of necropsy blood did not require any special methods of transport of specimens to the virus laboratory.

Aged↗
PubMed1970

Barbiturate blood levels found at necropsy in proven cases of acute barbiturate poisoning.

In order to determine whether blood barbiturate levels could be used to ascertain that death had been caused by barbiturate overdose, samples of blood from 128 subjects of coroners' necropsies were examined for barbiturate content. Sixty of these were well authenticated cases of barbiturate overdosage, and barbiturates were implicated, together with other factors such as alcohol and carbon monoxide, in a further 16 cases. The remaining 52 cases were of an eliminatory nature, 10 of which had low barbiturate blood levels considered to be within the therapeutic range.The results indicate that when the accepted levels producing loss of consciousness are exceeded, and maintained, death will ensue if treatment is not given. These results may be of value in assessing findings in necropsies requested by the coroner, and are in no way applicable to the living patient in whom it is well established that recovery from higher blood levels may take place if adequate treatment is available.

Amobarbital↗