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Biomedical subjects

E C Sweeney

Publications and source records attributed to E C Sweeney.

At least 37 records · Page 2Linked to original sources
PubMed1992

Cloning and characterization of a Candida albicans maltase gene involved in sucrose utilization.

In order to isolate the structural gene involved in sucrose utilization, we screened a sucrose-induced Candida albicans cDNA library for clones expressing alpha-glucosidase activity. The C. albicans maltase structural gene (CAMAL2) was isolated. No other clones expressing alpha-glucosidase activity. were detected. A genomic CAMAL2 clone was obtained by screening a size-selected genomic library with the cDNA clone. DNA sequence analysis reveals that CAMAL2 encodes a 570-amino-acid protein which shares 50% identity with the maltase structural gene (MAL62) of Saccharomyces carlsbergensis. The substrate specificity of the recombinant protein purified from Escherichia coli identifies the enzyme as a maltase. Northern (RNA) analysis reveals that transcription of CAMAL2 is induced by maltose and sucrose and repressed by glucose. These results suggest that assimilation of sucrose in C. albicans relies on an inducible maltase enzyme. The family of genes controlling sucrose utilization in C. albicans shares similarities with the MAL gene family of Saccharomyces cerevisiae and provides a model system for studying gene regulation in this pathogenic yeast.

Amino Acid Sequence↗
PubMed1988

Effect of treatment on Campylobacter pylori in peptic disease: a randomised prospective trial.

This study investigated the effect of colloidal bismuth subcitrate and cimetidine on Campylobacter pylori in peptic disease. In 74% of 135 patients with peptic disease diagnosed at endoscopy C pylori was detected before treatment. Compared with cimetidine, colloidal bismuth subcitrate significantly decreased the incidence of C pylori after six weeks of treatment (p less than 0.001). In the colloidal bismuth subcitrate group, subsequent healing of the lesion was correlated with the clearance of C pylori, unlike in the cimetidine group. C pylori was strongly associated with the presence of histological gastritis, which was decreased by colloidal bismuth subcitrate (p less than 0.001).

Adult↗
PubMed1987

The relationship of endocrine cells, dysplasia and carcinoembryonic antigen in Barrett's mucosa to adenocarcinoma of the oesophagus.

This study was undertaken to assess the prevalence and characteristic hormonal profile of endocrine cells in Barrett's mucosa and to determine to what extent this profile was shared by endocrine cells of adenocarcinomas arising therefrom. In addition, lower oesophageal carcinomas, not associated with columnar metaplasia, were examined to see if they exhibited a different hormonal profile. The patients studied comprised 43 who had had multiple oesophageal biopsies. 35 who had had oesophagogastric resection for adenocarcinoma arising in Barrett's mucosa and 26 in whom the resection showed no metaplastic epithelium adjacent to tumour. Argyrophil cells were present in 90% of biopsies and resections of Barrett's mucosa combined, irrespective of the histological type of metaplastic epithelium. By immunocytochemistry the most frequently identified substance in mucosal endocrine cells was serotonin (82%) followed by somatostatin (54%), secretin (22%) and pancreatic polypeptide (17%). Gastrin, bombesin, cholecystokinin, ACTH and substance P were not identified in metaplastic mucosa in any case. The difference in expression of serotonin by endocrine cells of tumours arising in Barrett's mucosa (31%) and those not (3.8%) was statistically significant (P less than 0.0186). Carcinoembryonic antigen (CEA) was demonstrated in 60% of oesophageal carcinomas, both endocrine positive and endocrine negative. Focal CEA expression was seen in 4.6% of biopsies and 14% of Barrett's mucosa adjacent to tumour. These results indicate a higher prevalence of endocrine cells in Barrett's mucosa than hitherto documented and suggest that serotonin may be a useful marker in distinguishing between primary oesophageal and putative gastric cancers at the gastro-oesophageal junction. The identification of CEA in oesophageal columnar epithelium is of little value in predicting the development of malignancy.

Adenocarcinoma↗
PubMed1987

Modification of caecal lymphoid tissue and relationship to granuloma formation in sporadic ileocaecal tuberculosis.

The histopathology of eight cases of sporadic ileocaecal tuberculosis is described with particular reference to caecal lymphoid tissue. Adjacent to areas of ulceration in all cases there was an increase in lymphoglandular complexes (LGC) and proliferation of paravascular lymphoid aggregates deeper in the gut wall. Early and fully-developed granulomas were present in locations comparable to LGC and lymphoid aggregates. Immunocytochemical staining of paraffin sections with monoclonal antibodies UCHL1 (T-lymphocyte membrane antigen) and LN-1, LN-2 and LN-3 (B-lymphocyte and Ia antigens) showed that central cells in LGC and lymphoid aggregates stained like follicular centre B-lymphocytes. Both LGC and lymphoid aggregates had a distinct peripheral rim of cells staining as T-lymphocytes, but LN-2 and LN-3 also stained scattered peripheral cells, some of which were recognizable as interdigitating reticulum cells. Most lymphocytes within and around granulomas stained as T-lymphocytes. In lymph nodes, granulomas appeared to occur first at the periphery of, and later to efface, cortical follicles. Lymph node compartments showed the expected T- and B-zonation, and lymphocytes associated with granulomas stained as in caecal granulomas. Our observations suggest that LGC are sites of mycobacterial antigen sampling, of T-lymphocyte and macrophage activation, and of (potential) granuloma formation in ileocaecal tuberculosis. Lymphoid aggregates deeper in the gut wall probably subserve a similar function during extension of the lesion. The location of both LGC and lymphoid aggregates beside lymphatics is suited to the transfer of their cellular constituents throughout the gut and to regional lymph nodes.

Aged↗
PubMed1986

The prevalence, prognostic significance and hormonal content of endocrine cells in gastric cancer.

Twenty-six of 100 cases of gastric adenocarcinoma contained argyrophil cells. All these tumours were carcino-embryonic antigen positive and 13 contained variable amounts of gastro-enteropancreatic peptides and amines. There was no significant difference in mucin type, extent or incidence of intestinal metaplasia between tumours with and those without endocrine cells. The prognosis for both groups was similarly poor, contrasting with that for carcinoid and atypical carcinoid. Endocrine cell hyperplasia was evident in the adjacent mucosa in some of the cases of endocrine positive tumours. There was no association between achlorhydria and the presence of endocrine cells in the tumours. The origin of the neoplastic endocrine cells remains speculative, occurring either as a mutation of a single stem cell or as a synchronous malignant transformation of two epithelial cell types exposed to a particular carcinogenic factor(s). Adenocarcinomas containing endocrine cells appear to be as biologically aggressive as the usual adenocarcinomas of the stomach and therefore should be treated in a like manner.

APUD Cells↗
PubMed1986

Lymphoglandular complexes of the colon: structure and distribution.

The structure and distribution of lymphoglandular complexes of the colon are described. The cellular composition of these complexes, as detailed by immunohistochemistry and electron microscopy, suggests that they are sites of antigen processing. Variations in structure and in the number of complexes that are found in certain colonic diseases are documented.

B-Lymphocytes↗
PubMed1986

Progress of bleomycin-induced lung fibrosis in rabbits.

Progression of lung fibrosis induced in rabbits by intratracheal bleomycin (BLM, 10 mg/kg) was monitored by biochemical and morphological measurements. These indicated that the evolution of fibrosis in the rabbit was slower than in other experimental animals. Histology revealed cellular and fibrocellular lesions 4 weeks after BLM. At 8 weeks these lesions still predominated, indicating continuing active disease accompanied by a progression to fibrosis. The gradual progression of the response was reflected in alterations in lung composition. Changes in lung content of collagen, protein and DNA were evident at 8 weeks after BLM, at which time concentration (micrograms/mg dry weight) of collagen and protein were also elevated (P less than 0.05). Plasma angiotensin converting enzyme (ACE), a marker of endothelial injury, decreased 1 week after BLM (P less than 0.01) and then returned to normal, indicating that endothelial injury does not parallel the fibrotic response. In summary, the continuing active inflammation and slow progress of fibrosis induced by i.t. BLM in the rabbit suggests that this model has advantages over others for the serial study of the cellular and biochemical evolution of lung fibrosis.

Animals↗
PubMed1982

Drugs and sperm.

Explore the source record for details and available documents.

Chloramphenicol↗
PubMed1981

Medullary carcinoma of the thyroid presenting as tumours of the pharynx and larynx.

Two cases of medullary carcinoma of the thyroid presenting as tumours of the pharynx and larynx are described. One patient had a tonsillar mass that resembled a carotid body tumour clinically, radiologically and microscopically. The other had an arytenoid tumour with multiple cervical lymph node metastases but without intrathyroidal carcinoma. The endocrine nature of the neoplasms was indicated by the presence of stromal amyloid, cellular argyrophilia and secretory granules whilst the demonstration of calcitonin and carcinoembryonic antigen provided evidence that they were medullary carcinomas.

Aged↗
PubMed1980

Adenoid cystic carcinoma of the esophagus: a light and electron microscopic study.

The light and electron microscopic appearances of adenoid cystic carcinoma of the esophagus are presented. Typical light microscopic features of adenoid cystic carcinoma were seen, but a unique additional feature was the presence at one edge of the tumor of gland-like structures lined entirely by tumor cells and opening onto an intact esophageal epithelium. Electron microscopy showed cystic spaces containing replicated basement membrane surrounded by epithelial cells with occasional myoepithelial cells at the interface. Rare lumina were seen between the cells with microvilli projecting into them. Occasional epithelial cells contained granules of neurosecretory tape. Both the light and electron microscopic findings strongly support an origin from the intercalated duct of esophageal mucus glands. The paucity of gland lumina may represent a lesser degree of differentiation which would accord well with the known biological aggressiveness of the tumor at this site.

Basement Membrane↗
PubMed1980

Atypical gastric carcinoids.

Four examples of infiltrating gastric tumours which had light microscopic features suggestive of carcinoid or oat-cell carcinoma are documented. Histological and ultrastructural findings indicated that these tumours were atypical carcinoids. A spectrum of endocrine cell neoplasia in the stomach analogous to that observed in the bronchus is postulated. It is felt that increased recognition of poorly differentiated endocrine tumours of the stomach might be of prognostic and therapeutic importance.

Adult↗