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Biomedical subjects

J F Lewin

Publications and source records attributed to J F Lewin.

11 recordsLinked to original sources
PubMed1992

Transmucosal penetration of bismuth particles in the human stomach.

Electron microscopic examination of upper gastrointestinal biopsies with x-ray microanalysis was used to detect electron-dense particles of bismuth in the mucosa of the upper gastrointestinal tract, 30-60 minutes after oral dosing with either tripotassium dicitrato bismuthate [De-Noltab; Brocades (Great Britain) Ltd., Weybridge, UK; five patients] or bismuth salicylate (Pepto-Bismol; Richardson Vicks Ltd., Egham, UK; five patients), or without dosing (two patients). Transmucosal penetration of bismuth particles was observed in the gastric antral mucosa of all patients who had been dosed with tripotassium dicitrato bismuthate, but there was no penetration after oral dosing with bismuth salicylate. Persorption of bismuth particles through the gastric mucosa to the vascular endothelium provides an explanation for the rapid rise of plasma bismuth concentration observed only after oral dosing with tripotassium dicitrato bismuthate.

Adult↗
PubMed1991

'Neuroendocrine' differentiation in primary neoplasms of the liver.

Thirty primary liver neoplasms (16 hepatocellular, nine biliary, and five epithelioid haemangioendotheliomas) were studied for the expression of the general 'neuroendocrine' markers, neurone specific enolase (NSE) and protein gene product 9.5 (PGP 9.5). Grimelius silver staining for neurosecretory granules and immunostaining for S100 protein, HMB-45, vasoactive intestinal polypeptide (VIP), and calcitonin were also performed. Eleven of the 16 hepatocellular carcinomas stained positively for PGP 9.5, four for NSE, six for HMB-45, and two for S100 protein. Seven exhibited granular staining by the Grimelius method; eight showed immunostaining for VIP, and two for calcitonin. Three of the five haemangioendotheliomas demonstrated positive immunostaining for PGP 9.5, and two for NSE; of the nine biliary carcinomas, two showed staining for PGP 9.5 and NSE, and four contained cells staining with the Grimelius technique. Primary neoplasms of liver may show 'neuroendocrine' differentiation and this aspect of their phenotypic expression has to be considered before predicting the site of origin of a tumour in the liver.

Bile Duct Neoplasms↗
PubMed1981

Minimizing sample error in transmission electron microscopy.

The last few years have seen an increase in the use of electron microscopy, both for research and as a diagnostic tool in pathology. With the increase in the number of specimens being used for diagnostic purposes, limitations due to sampling error have become apparent. The method described is designed to help overcome this problem.

Microscopy, Electron↗
PubMedDate not supplied

Computer storage of toxicology methods and postmortem drug determinations.

Two data bases have been developed by toxicologists from the Department of Scientific and Industrial Research in New Zealand. The data bases are designed to store and retrieve postmortem drug and poison levels (TOXFILE) and methods used in drug and poison determinations (TOXMETH). TOXFILE contains a list of all the analytical results determined in toxicological cases received by the three laboratories. This method of storing the data has been found superior to the previously used card systems. The file also contains a reference to the analytical method which is very important for the interpretation of the results. TOXMETH contains a list of the analytical methods which have been developed and are in use in one or more of the three Chemistry Division toxicology laboratories. Methods can be added, modified and superseded as approaches change. A Chemistry Division Report (Pannell, L.K. et al., Chemistry Division Report No. CD: 2195, 1983) has been published containing all the programs and instructions. Copies of this are available from the authors on request. Computer magnetic tapes of the programs, the report and the data are also available. The names of the deceased on the TOXFILE data file are encrypted to provide increased security of the information. The TOXFILE data file which will be supplied on magnetic tape to overseas laboratories will have the name file on all records changed to 'CD' to provide complete confidentiality.

Autopsy↗
PubMedDate not supplied

Determination of potentially toxic metals in human livers in New Zealand.

Ninety-six human liver samples from persons who died as a result of physical injuries in New Zealand have been analysed for arsenic, cadmium, chromium, cobalt, copper, mercury, lead, manganese, nickel, selenium, silver, and zinc. The levels found were generally lower than those found in similar studies outside New Zealand. Cadmium and lead levels showed a positive correlation with age and there did not appear to be any major regional variations within New Zealand.

Adolescent↗