Biomedical subjects

M A Gregory

Publications and source records attributed to M A Gregory.

49 records · Page 3Linked to original sources

PubMed1982

Changes in the morphology of villar epithelial cells adjacent to duodenal ulcers during the process of healing.

Fifteen patients with active duodenal ulcers were treated for 6 weeks with ulcerone, aluminium sucrose sulphate, or bromazepam to promote healing. Biopsies taken from the edge of ulcers before treatment showed an epithelium exclusively populated with cells of a mucus-secreting type which resembled those normally found in the gastric antrum. Biopsies taken at endoscopy from the edge of ulcers or scars at time intervals during treatment to endoscopic healing showed, irrespective of the drug used, a sequence of ultrastructural changes in villar epithelial cells, from a gastric secretory to a duodenal absorptive cell type. We suggest that the gastric cells in the duodenum are derived from stem cells in the crypts of Lieberkühn surrounding an ulcer and are produced in response to luminal fluids of abnormally low pH. Their function is probably protective, in that they isolate regions of ulceration from the healthy mucosa and, by the continuous secretion of gastric mucin, protect the ulcer from the harmful effects of luminal acids. Their transformation to absorptive cells during ulcer healing is part of a natural sequence that is aided by, but not dependent on, drug therapy.

Bismuth↗

PubMed1981

Transmission electron microscopy of human oesophageal carcinomas.

Twelve human oesophageal carcinoma samples were examined by both light and electron microscopy in order to characterise the ultrastructural features of this neoplasm. Those samples from well differentiated tumours contained abundant tonofilaments, mainly in a paranuclear position, while cells from poorly differentiated tumours displayed few such filaments but had more prominent cytoplasmic organelles. Desmosomes were well developed in all samples, some of which displayed numerous clearly defined intracellular desmosomes not necessarily associated with cell membrane material. Myelinoid figures were abundant and the bizarre forms which were present in some samples may be related either to abnormal metabolism or to viral activity. Glycogen, lipid droplets and intermediate filaments, possibly related to basement membrane material were observed in several samples. No single feature diagnostic for carcinoma of the oesophagus emerged from this study, but several structural similarities between oesophageal and other carcinomas were noted.

Cell Nucleus↗

PubMed1980

Compatibility of blood with solutions containing calcium.

Blood anticoagulated with citrate-phosphate-dextrose (CPD) was run through blood administration sets before and after Ringer-lactate solution (BP), Hidroliet, Maintelyte, Plasmalyte B and 0,9% saline. Clots, some of which were proven by electron microscopy to contain fibrin, formed distal to the filter when Ringer-lactate and Hidroliet were used, but not with other solutions. It is suggested that their formation was due to the calcium in Ringer-lactate and Hidroliet. As these two solutions are frequently used in combination with blood, especially in shocked patients, and as the clots would presumably be filtered out in the lung, it would seem wise to use either calcium-free Ringer-lactate solution or some other crystalloid solution such as 0,9% saline or Plasmalyte B.

Blood Coagulation↗

PubMed1980

Growth patterns, ultrastructure, and chromosomal constitution of normal kidney and nephroblastoma cells in short-term culture.

Nephrectomies were performed on four children with nephroblastomas (Wilms' tumor). Tumor tissue and normal kidney tissue were taken from each patient and were cultured. The in vitro characteristics of the cultured cells were then compared with their known in vivo characteristics. The normal kidney cells showed uniform cell morphology, had a relatively slow and orderly growth pattern and had the usual diploid chromosomal constitution. The tumor cells on the other hand were irregular in morphology and had a rapid and disorderly growth pattern. Electron microscopic examination confirmed the variation in the tumor cell morphology. In addition, microfilaments were seen to be abnormally abundant in many of the cells and some cells contained membrane-bound granules. Desmosomes were absent. Chromosome analyses showed cells from three of the nephroblastoma samples to maintain a constant hyperdiploid karyotype during the first few passages in vitro, whereas the normal kidney cells continued to have the normal diploid karyotype. Our study suggests that nephroblastoma and normal kidney cells are stable in culture, that is they retain most of their cellular characteristics in vitro and do not undergo rapid dedifferentitation in short-term culture.

Cell Division↗

PubMed1979

Ultrastructural artefacts in biopsied normal myocardium and their relevance to myocardial biopsy in man.

Biopsy specimens, as a source of myocardial tissue, are being used increasingly in the appraisal of various myocardial diseases. A study of myocardial tissue, biopsied and processed in various ways, and obtained from normal healthy experimental animals, showed that a variety of artefacts may be found. These artefacts develop in reactive, beating myocardium but not in non-reactive hearts. The artefacts are in many instances similar to, or mimic, changes previously described as pathological in origin. This is most unsatisfactory, and if valid pathological appraisals of myocardial biopsies are to be made, a technique allowing the recovery of tissue, free of biopsy artefact, is required. Such a technique is described.

Animals↗

PubMed1979

Does the duodenal cell ever return to normal? A comparison between treatment with cimetidine and denol.

After six weeks therapy with the bismuth-containing substance Denol, the ultrastructure of the duodenal cell is normal in most cases. Following therapy with the histamine-2 receptor antagonist (cimetidine), for the same period and even after one year continuous therapy, the denodenal cell remains abnormal in most instances. This may explain the frequent relapse of duodenal ulcers after cimetidine treatment.

Anti-Ulcer Agents↗

PubMed1974