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Biomedical subjects

I M Dawson

Publications and source records attributed to I M Dawson.

At least 19 recordsLinked to original sources
PubMed1992

An intracellular study of the action of NAN-190 on neurons in the dorsal raphe nucleus of the rat.

Intracellular recordings have been made from neurons in the dorsal raphe (DR) nucleus of the rat to determine the mechanism of action of the arylpiperazine compound NAN-190. Application of NAN-190 (50 microM) alone most frequently caused a hyperpolarization accompanied by a fall in RM and reduced the response to 5-HT and 8-OH-DPAT. After pretreatment of the preparation with the 5-HT-uptake blocker citalopram (10 microM) NAN-190 exerted an excitatory effect. It is concluded that NAN-190 is a partial agonist in the DR nucleus.

8-Hydroxy-2-(di-n-propylamino)tetralin↗
PubMed1982

The maternal autopsy.

Careful study of reports prepared for the Confidential Enquiries into Maternal Deaths in England and Wales has made it clear that many maternal autopsy reports are not as informative as they might be. This is, in part at least, because no pathologist who does not work in a maternity unit can expect to see more than a handful of such deaths in a working lifetime. This paper describes briefly the particular features to look for at autopsy, stresses the importance of taking adequate material for histology and discusses some of the more significant histological findings, both of conditions which cause death and of those commonly associated with it.

Autopsy↗
PubMed1977

Morphology and staining patterns of endocrine cell tumours in the gut, pancreas and bronchus and their possible significance.

We have studied 109 endocrine cell tumours of the gastrointestinal tract, pancreas and bronchus in terms of histological pattern and histochemical staining with immunocytochemical studies on seven tumours. As a result we believe that previous histological classifications need modification. 5-Hydroxytryptamine secreting tumours have a carcinoid (A1) pattern with, in some cases, an additional tubuloacinar element (A1A2) and definable histochemical reactions; well differentiated gastrinomas, insulinomas and glucagonomas are associated commonly, but not exclusively, with particular histological patterns and argyrophilia, but no such association exists for less differentiated tumours. This may be related to the synthesis of precursor hormones by less differentiated tumours. Mixed patterns are common, particularly in tumours of foregut derivation. Prospective studies planned to correlate histology, histochemistry, immunocytochemistry and ultrastructure are needed on all endocrine cell tumours.

Bronchial Neoplasms↗
PubMed1974

An investigation into the enzyme histochemistry of adenocarcinomas of human large intestine and of the transitional epithelium immediately adjacent to them.

Histochemical enzymatic studies were performed on 30 freshly resected large bowel carcinomas, 30 samples of normal colonic epithelium, and six samples of the histologically normal epithelium (so-called transitional epithelium) immediately adjacent to a carcinoma. Five enzymes were studied: nicotine adenine dinucleotide tetrazolium reductase (NADH-TR), glucose-6-phosphate dehydrogenase, succinate dehydrogenase, monoamine oxidase, and acid phosphatase. QUANTITATIVE AND QUALITATIVE DIFFERENCES IN ENZYME ACTIVITY WERE OBSERVED BETWEEN NORMAL, TRANSITIONAL, AND CARCINOMATOUS MUCOSA AS FOLLOWS: monoamine oxidase activity was moderate in normal mucosa, high in transitional mucosa, and low in carcinoma. Succinate dehydrogenase activity was high in transitional mucosa and low or moderate in normal and carcinomatous mucosa. Glucose-6-phosphate dehydrogenase activity showed a gradation from low in normal mucosa to high in carcinoma while acid phosphatase showed the reverse of this pattern. The tetrazolium reductase activity was low or moderate in normal and transitional mucosa and high in carcinoma. These differences in enzyme activity and their possible clinical and metabolic significance are discussed.

Acid Phosphatase↗
PubMed1971

The value of electron microscope studies in diagnosing malignant change in ulcerative colitis.

Ultrastructural and histological appearances were studied in normal rectal and colonic mucosa, in the mucosa immediately adjacent to neoplasms (transitional mucosa), in neoplasms themselves, and in ulcerative colitis to try to determine whether any changes found in colitis might be recognized as premalignant. Two of the ulcerative colitis specimens showed histological evidence of premalignant change and these changes were reflected at the ultrastructural level. No electron microscopical premalignant changes were found which could not more easily be detected by simple histology, and it is concluded that attempts to detect premalignant changes in ulcerative colitis using electron microscopical techniques are likely to be unrewarding.

Colitis, Ulcerative↗