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Biomedical subjects

W A Reid

Publications and source records attributed to W A Reid.

At least 19 recordsLinked to original sources
PubMed1992

Diagnosis of the acute ischaemic heart by ion elution from myocardium.

The post-mortem diagnosis of acute myocardial ischaemia may be difficult to establish in the absence of morphological changes in the myocardium or recent coronary thrombosis. Ischaemic cell injury leads to potassium (K) efflux and sodium (Na) influx and, if the blood is still circulating, the K:Na ratio of the tissue falls. In this study, the K:Na ratio was measured by eluting the ions from samples of myocardium and assaying the eluate. The method yields similar results to those obtained by a previous method, in which myocardial samples were homogenized. The K:Na ratios on samples of horizontal slices through the heart were plotted on maps of the slices. A low K:Na ratio corresponded to, but extended beyond, areas where there was morphological evidence of ischaemia. The method is simple and may be of use in routine practice.

Acute Disease↗
PubMed1991

Immunohistochemical and other features of breast carcinomas presenting clinically compared with those detected by cancer screening.

Features of 111 mammary carcinomas derived from breast cancer screening were compared with those of 69 carcinomas presenting 'clinically'. Screen detected cancers were smaller, had less likelihood of nodal metastases, included a higher proportion of in situ tumours and if invasive, tended to be of lower grade. Using immunohistochemical methods, the expression of c-erbB-2 oncoprotein, epidermal growth factor receptor (EGFR) and cathepsin D were compared in the two groups. A similar proportion of screened and unscreened tumours expressed c-erbB-2 oncoprotein and EGFR but expression of the oestrogen regulated protein cathepsin D was significantly more frequent in the screened group (P less than 0.05). Although a relatively small series, the results suggest a biological difference between 'screened' and 'clinical' tumours.

Breast Neoplasms↗
PubMed1990

Identification of primary tumour site by immunolocalization of progastricsin in metastatic adenocarcinoma.

The aspartic proteinase zymogen, progastricsin, which occurs in normal gastroduodenal mucosa and prostate, has been localized by the immunogold-silver method in formalin-fixed, paraffin-embedded sections of metastatic adenocarcinoma in lymph nodes and liver, the primary site being known in each case. Progastricsin was demonstrated in 16 of 84 lymph node metastases, including 7 of 17 from stomach, 2 of 2 from prostate, and 7 of 65 from other sites. Progastricsin was also found in 19 of 98 hepatic metastases, including 8 of 22 from stomach, 6 of 24 from pancreas, and 5 of 52 from other sites. The presence of progastricsin in a metastasis correlated well with a primary tumour in the stomach or prostate or, less significantly, pancreas. Immunolocalization of progastricsin in a histological section of metastatic adenocarcinoma may help to locate the primary site.

Adenocarcinoma↗
PubMed1990

Cationic antiprotozoal drugs. Trypanocidal activity of 2-(4'-formylphenyl)imidazo[1,2-a]pyridinium guanylhydrazones and related derivatives of quaternary heteroaromatic compounds.

A series of quaternary 2-phenylimidazo[1,2-a]pyridinum salts has been prepared and evaluated for antiparasitic activity. Primary attention was focused on derivatives with amido, substituted hydrazone, and heterocyclic functionality at the para position of the phenyl substituent. Guanylhydrazones and N-substituted guanylhydrazones of the 4'-formyl-substituted compounds are very active against the blood state Trypanosoma rhodesiense in mice by subcutaneous or oral administration. The most potent compounds attain 100% survival for 30 days at doses of less than 1.0 mg/kg (sc) and greater than 5.0 mg/kg (po). Weaker activity is noted for certain other 4'-substituents such as carboxamidines and carboxamide oximes. Considerable variation in structure, including replacing of the imidazo [1,2-a]pyridinium ring by other cationic heterocyclic rings and insertion of linking groups between the heterocyclic ring and phenyl group, can be done, and a high level of activity is maintained. Relationships between these structural changes and biological activity are discussed.

Animals↗
PubMed1990

Immunolocalization of cathepsin D in the human central nervous system and central nervous system neoplasms.

The cellular distribution of the lysosomal proteinase cathepsin D was studied in a series of 76 neoplasms and 18 non-neoplastic tissues from the human central nervous system, using a well-characterized polyclonal antibody in a peroxidase-antiperoxidase technique. In the normal and developing brain, cathepsin D is confined to neurons and choroid plexus epithelium. Strong granular cytoplasmic staining was present in neuronal and choroid plexus neoplasms, and in reactive macrophages. A large variety of other neoplasms also exhibited positive cytoplasmic staining, albeit usually of a weaker diffuse type. Cathepsin D cannot be considered a specific marker for neuronal or choroid plexus neoplasms, but the antiserum used in this study may be of value in antibody panels for the investigation of these tumours. Its localization may also be of value in embryological studies, particularly in the cerebellum, and in investigations of steroid hormone receptor-associated proteins in meningiomas and Schwannomas.

Brain Neoplasms↗
PubMed1989

Immunolocalisation of aspartic proteinases in the developing human stomach.

The distribution and time of appearance in the developing human stomach of the 4 aspartic proteinases, pepsinogen, progastricsin, slow-moving protease and cathepsin D, all present in gastric carcinoma, has been determined by the peroxidase-antiperoxidase method on formalin fixed paraffin embedded sections of fetal stomach. Slow-moving protease appears to be the dominant enzyme from 12 weeks gestation onward, although progastricsin is also present at this time. Pepsinogen and cathepsin D do not appear until 17-18 weeks.

Aspartic Acid Endopeptidases↗
PubMed1987

The labile nature of the insulin signal(s) for the stimulation of DNA synthesis in mouse lens epithelial and 3T3 cells.

A kinetic study was carried out to assess the stability of the intracellular signal(s) generated by insulin in quiescent cells for the stimulation of DNA synthesis. Using murine lens epithelial cells and Swiss 3T3 cells in culture, it was found that insulin stimulated DNA synthesis after a lag of 14.5 h. If, however, 6 h after the addition of insulin to the cells, the insulin-containing media were totally removed, followed by the addition of fresh media (even if insulin was returned to the medium within approximately 10 min), a 14.5-h lag still remained after insulin readdition before DNA synthesis started. In another set of experiments, the insulin was removed after 6 h by diluting its concentration approximately 60,000-fold. In this case, if insulin was at the diluted concentration for approximately 60 min before being added back, a full 14.5 h was necessary for the start of DNA synthesis. The half-time for loss of signal was 2 +/- 1 min for total washout and 18.4 +/- 0.5 min for the dilution experiment. These results indicate that the intracellular signal(s) for DNA synthesis produced by the binding of insulin to its cellular receptor are extremely transitory in nature. The signal disappears at approximately the same rate that insulin dissociates from the receptor. Thus, insulin must be constantly binding to the membrane receptor in order to keep the key signal(s) at a high enough level for the cell to progress on to S phase. Early events, such as specific protein synthesis, changes in ion flux, changes in cellular metabolism, and changes in cellular pH, may be essential, but they are not sufficient to cause a cell to progress on to S phase. Addition of sodium vanadate to the cell is found to stabilize the messenger such that there is no loss of signal when insulin is removed. These data are consistent with the tyrosine-phosphorylated insulin receptor or a product of its action being the signal.

Animals↗
PubMed1987

Continual audit of clinical diagnostic accuracy by computer: a study of 592 autopsy cases.

In a prospective study of 592 autopsy cases, correlations between clinical and pathological data were made by computer from a novel protocol on which morphological and functional diagnoses were separated. The accuracy of diagnosis was analysed with respect to time in hospital, specialty, consultant in charge, and other criteria. Overall, there were 168 clinical 'overdiagnoses', not confirmed at autopsy; 492 'underdiagnoses', not made clinically; and 432 'agreements' between clinical and pathological diagnoses. The computer program allows the data to be analysed at any time as the number of cases increases. Entry of information entails comparatively little extra work and a similar system could be incorporated into the service commitment of any pathology department with a suitable microcomputer and access to a mainframe computer.

Autopsy↗
PubMed1987

The effect of diffusion on the immunolocalization of antigen.

Diffusion prior to tissue fixation may result in immunohistochemical localization of antigen at sites in which it does not occur in vivo. The extent and speed with which this may occur have been investigated with several antigens of different molecular weights in tissues which were left unfixed for various lengths of time. There was clear evidence of diffusion when fixation was delayed for as little as 1 h, resulting in focal labelling of cells which did not contain antigen in rapidly fixed tissues. Falsely localized antigen was particularly evident adjacent to sites containing high antigen concentrations and might be expected in areas permeated by antigen-containing tissue fluid. These findings substantiate the view that diffusion of antigen should be considered as a cause of false positivity in any immunolocalization study.

Animals↗
PubMed1987

Cost effectiveness of routine postmortem histology.

In a retrospective study of the records of 160 necropsies it was found that, according to the clinical and gross necropsy findings, no clinically important abnormality would have been anticipated in 46% of the tissue samples. The estimated annual cost of processing this material alone was pounds 10,500, including the salary of one full time medical laboratory scientific officer (MLSO). Few of the microscopic findings led to a change in diagnosis. It is suggested that unselected postmortem histology is, for diagnostic purposes, not cost effective.

Autopsy↗
PubMed1987

Slow moving proteinase. Isolation, characterization, and immunohistochemical localization in gastric mucosa.

Human gastric mucosa contains three immunochemically distinguishable aspartic proteinases, pepsinogen I (pepsinogen A), pepsinogen II (pepsinogen C, progastricsin), and a nonpepsinogen proteinase also termed slow moving proteinase (SMP). The properties of SMP, and in particular its relationship to another aspartic proteinase, cathepsin D, were examined in this study. Slow moving proteinase and cathepsin D were isolated, respectively, from gastric mucosa and human spleen. Antiserum specific to each proteinase was prepared in rabbits. Rabbit anti-SMP did not recognize cathepsin D, and conversely, anticathepsin D did not react with SMP. Immunohistochemical studies localized SMP to surface epithelial cells in both the fundic and pyloric gland areas of the stomach. In contrast, cathepsin D was found mainly in mononuclear cells in the lamina propria and in parietal cells. Slow moving proteinase exhibited considerably lower Km values for its interaction with two chromogenic substrates than did cathepsin D. An even greater distinction between the two enzymes was found with the protein inhibitor from Ascaris lumbricoides; the activity of SMP was inhibited very strongly, whereas that of cathepsin D was not affected. By sodium dodecyl sulfate-polyacrylamide gel electrophoresis under denaturing conditions, SMP consisted of two subunits with apparent molecular weights of 42,500 and 41,000. The last two properties characterize a less-well-known aspartic proteinase, cathepsin E. We conclude that SMP is not cathepsin D, but that it may be cathepsin E.

Cathepsin D↗