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Biomedical subjects

G Stamp

Publications and source records attributed to G Stamp.

At least 37 records · Page 2Linked to original sources
PubMed1995

Protein extraction and western blotting from methacarn-fixed tissue.

Polyacrylamide gel electrophoresis (PAGE) of proteins with subsequent western blotting has become a routine technique for the analysis of proteins from both cultured cells and fresh whole tissue. We have developed a method to extract proteins from methacarn-fixed tissue which renders them suitable for SDS-PAGE and western blotting. With a panel of antibodies to specific intermediate filaments, transforming growth factor-alpha (TGF-alpha), and albumin, immunohistochemistry was performed in parallel with western blotting on sections cut from methacarn-fixed samples of normal rat liver and liver from rats treated under a regime which induces oval cell proliferation. Immunohistochemistry enabled the determination of changes in tissue distribution and abundance of the target proteins, which was mirrored by the corresponding western blot data. This technique can be especially effective when used in conjunction with immunohistochemistry. Tissue samples are easy to prepare, avoiding the precautions which need to be taken when handling fresh tissue (Abstract: J Pathol 1994; 173S: No. 41).

Acetates↗
PubMed1995

Extranodal follicular dendritic cell sarcoma of the gastrointestinal tract. Morphologic, immunohistochemical and ultrastructural analysis of two cases.

Tumors showing differentiation toward follicular dendritic cells are rare and usually occur in lymph nodes. Their occurrence at extranodal sites was recognized recently. This report documents two further extranodal cases, one arising in the small intestine of a 23-year-old woman and the second in periduodenal retroperitoneal soft tissue of a 63-year-old man. Both neoplasms displayed a typical biphasic morphologic pattern, composed of large cells with indistinct cytoplasmic borders creating a syncytial appearance, admixed with spindle cell areas resembling malignant fibrous histiocytoma, and infiltrated by numerous small T lymphocytes. Expression of CD21 and CD35, together with ultrastructural demonstration (in one case) of long cytoplasmic processes connected by desmosomes, confirmed follicular dendritic cell differentiation. One case also expressed HLA-DR, and both showed aberrant epithelial membrane antigen staining. Neither tumor showed CD45 expression. In both cases the tumors were treated by local excision. Case 1 has shown an unusually aggressive course with extensive intraperitoneal recurrence. The biphasic morphologic pattern and tumor immunophenotype are discussed in relation to increasing evidence of immunophenotypic and morphologic heterogeneity of normal follicular dendritic cells.

Adult↗
PubMed1995

Integrins in tumour development and spread.

The study of integrin receptor expression and function in carcinomas will undoubtedly increase our understanding of the malignant process and clarify the relative importance of the numerous alterations that are identified. Whether this will lead to direct clinical applications is not clear at present, but it will certainly alter our approach to the evaluation of cancer treatment. The more immediate search for prognostic indicators and metastatic site preference in tumours expressing a particular integrin profile is partly hampered by the small numbers of cases studied in most series, where observed trends in tumour subsets barely achieve significance. Perhaps the next phase should be to evaluate promising approaches in large multicentre studies to establish the relative importance of these trends in tumour prognosis and response to treatment, preferably by developing reagents that will permit the demonstration of integrins in routinely processed archival material from human tumour specimens. Future developments in therapy may depend on the knowledge that may emerge from such work.

Animals↗
PubMed1993

Trefoil peptide gene expression in gastrointestinal epithelial cells in inflammatory bowel disease.

BACKGROUND: This work expands on recent observations that the trefoil peptides pS2 and human spasmolytic polypeptide (hSP) are expressed in the ulceration-associated cell lineage (UACL) glands developing in chronic ulcerative conditions. METHODS: Trefoil peptide expression in small intestinal Crohn's disease was examined by in situ hybridization to reveal sites of expression of the messenger RNAs encoding pS2 and hSP and by immunohistochemistry and immunoelectron microscopy to localize the peptides in the UACL and adjacent goblet and neuroendocrine cells. RESULTS: Goblet cells near the UACL expressed pS2 messenger RNA and peptide; ultrastructural immunolocalization revealed pS2 copackaged within mucous cell granules. Neuroendocrine cell hyperplasia was marked in crypts near the UACL; pS2 was copackaged with the neuroendocrine granules. CONCLUSIONS: Copackaging of a secretory protein, pS2, in both mucous and neuroendocrine granules, which have different functions, is unusual and indicates an important role for pS2 in the secretory process itself or as a ligand delivered to its receptors via different routes. It is concluded that trefoil peptides are of considerable potential functional importance in inflammatory bowel disease.

Cell Line↗
PubMed1992

Radiation stricture of the biliary ducts: an emerging new entity?

Two patients with stricture of the extrahepatic biliary tree are described. Both patients presented with a clinical picture of obstructive jaundice one to two years following radiotherapy for a malignant condition. As no recurrent tumour was detected in either of the patients the strictures were considered to be the result of radiation therapy. Bilio-enteric decompression was performed in both patients who are well at follow up one and ten years after the procedure.

Adult↗
PubMed1992

Non-steroidal anti-inflammatory drugs inhibit the processes of mucosal cell proliferation associated with duodenal ulcer healing.

We demonstrate that, in patients taking non-steroidal anti-inflammatory drugs (NSAIDs), there is inhibition of the proliferation of mucosal cells that normally leads to healing of duodenal ulcers. A microdissection technique was used to quantitate mitosis in duodenal crypts at the ulcer edge, giving a regeneration index of mitotic rate at that site, as compared to nearby mucosa. In patients with duodenal ulcers occurring in the absence of NSAID therapy, there was a brisk regenerative response (median index 2.48, range 1.55-9.81, n = 8), significantly greater than in patients taking NSAIDs (median index 1.10, range 0.73-2.16, n = 10, p = 0.014). Inhibition of the process of epithelial cell division normally involved in duodenal ulcer healing could contribute to the delay in ulcer healing which may explain the higher complication rate for duodenal ulcer during NSAID therapy.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1992

Trefoil peptide expression in intestinal adaptation and renewal.

There are many avenues where molecular biology is important in studying the gut, and here we explore methods for defining expression of a new gene family in the gut. We have defined the pattern of trefoil peptide gene expression in the ulceration-associated cell lineage (UACL) and in the nearby mucosa in Crohn's disease. In the UACL, human spasmolytic polypeptide mRNA and peptide are expressed in the acinar and proximal duct cells, whereas pS2 mRNA and peptide are found in the distal duct cells and in the surface cells. In adjacent mucosa, pS2 mRNA and protein are expressed ectopically by goblet cells. Ultrastructural immunolocalisation showed the pS2 to be co-packaged in the mucous cell granules. pS2 peptide was demonstrated in local neuroendocrine cells and was also co-packaged with the neuroendocrine granules. The crypts associated with the UACL also showed marked neuroendocrine cell hyperplasia. We have also cloned the newest trefoil peptide intestinal trefoil factor from human and rat intestinal mucosa and shown its co-expression with mucus by normal intestinal goblet cells. The co-packaging of the same secretory protein in both mucous and neuroendocrine granules, which have different functions, is unusual and indicates an important role for pS2 in the secretory process itself or as a ligand delivered to its receptor via multiple routes. We conclude that the trefoil peptides are widely distributed in the intestine in inflammatory bowel disease and are of considerable potential functional importance.

Amino Acid Sequence↗
PubMed1992

Trefoil peptide gene expression in gastrointestinal epithelial cells in inflammatory bowel disease.

Trefoil peptides are a growing group of proteins with interesting structural and functional properties. We have defined the pattern of trefoil peptide gene expression in the ulceration-associated cell lineage (UACL) and in the nearby mucosa in Crohn's disease. In the UACL, human spasmolytic polypeptide (hSP) mRNA is expressed in the acinar and proximal duct cells, while pS2 mRNA and peptide are found in the distal duct cells and in the surface cells. In adjacent mucosa, pS2 mRNA and protein are expressed by goblet cells, with the pS2 peptide concentrated in the area of the Golgi and also in the theca. Ultrastructural immunolocalisation showed the pS2 to be co-packaged in the mucous cell granules before being secreted into the intestinal lumen. In addition, pS2 peptide was demonstrated in local neuroendocrine cells and was also co-packaged with the neuroendocrine granules. The crypts associated with the UACL also showed marked neuroendocrine cell hyperplasia. We conclude that pS2 peptide is secreted locally into the viscoelastic coat covering the intestinal mucosa which surrounds Crohn's disease ulcers. In addition, it is clear that intestinal goblet cells, in addition to producing mucins, are a rich source of regulatory peptides. Moreover, pS2 is clearly co-packaged with neurosecretory granules, which are released through basal and lateral membranes so that the contained peptides can act in a paracrine manner. These findings are interpreted in terms of the epidermal growth factor/urogastrone released by the UACL, stimulating pS2 gene expression in surrounding cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Crohn Disease↗
PubMed1992

Nonuniform expression of a mouse mammary tumor virus-driven int-2/Fgf-3 transgene in pregnancy-responsive breast tumors.

We have developed transgenic mice in which expression of the mouse int-2/Fgf-3 gene is regulated by a single long terminal repeat from mouse mammary tumor virus. Such mice contain and transmit a replica of the activated int-2/Fgf-3 allele present in a spontaneous mammary tumor from a BR6 mouse. Although free of infectious mouse mammary tumor virus and with a different genetic background, the transgenic mice develop pregnancy-responsive mammary epithelial proliferations that are similar to the early stages of tumorigenesis in the BR6 strain. Histological examination revealed that most of these tumors showed pronounced tubular and acinar structures, features usually associated with morphological differentiation. In some cases, the tumors were locally invasive, causing disruption of the dermis which manifested itself as local hair loss. In situ hybridization showed that patterns of transgene expression in the abnormal glands were markedly nonuniform. In contrast, mouse mammary tumor virus-induced neoplasms showed more uniform expression of int-2/Fgf-3, as did the urogenital epithelial proliferations that occur among males of this transgenic line. These data suggest that mammary tumors in virally infected animals may depend primarily on autocrine stimulation by the int-2/Fgf-3 gene product, whereas both autocrine and paracrine mechanisms may contribute to tumors and hyperplasias found in transgenic animals.

Animals↗
PubMed1991

Antitumor activity of gamma-interferon in ascitic and solid tumor models of human ovarian cancer.

We have investigated the action of recombinant human gamma-interferon (rHuIFN-gamma) against human ovarian cancer xenografts growing as ascites or as bulky solid i.p. tumors in nude mice. Both forms of the disease responded to i.p. rHuIFN-gamma with significant increases in mouse survival time, and in 2 of 3 ascitic models the mice were cured of peritoneal disease. The activity of rHuIFN-gamma was dose and schedule dependent, and xenografts derived from 3 different patients showed a heterogeneity of response. Peak i.p. levels of rHuIFN-gamma in nude mice bearing multiple i.p. solid tumors were similar to those found in ovarian cancer patients receiving i.p. rHuIFN-gamma, but clearance was more rapid in the mice. Rat gamma-interferon had no antitumor activity at the same doses and schedules although it had some biological activity in the nude mice. Histological examination of treated tumors revealed increased necrosis and loss of cellular organization with large areas of hypocellular epithelial mucin. These changes were preceded by a fall in tumor tryptophan and a rise in tumor kynurenine. We conclude that rHuIFN-gamma has a direct dose related antitumor effect on ovarian cancer xenografts that is preceded by increased metabolism of tryptophan.

Animals↗
PubMed1990

Inhibitory effect of non-steroidal anti-inflammatory drugs on mucosal cell proliferation associated with gastric ulcer healing.

To find out whether non-steroidial anti-inflammatory drugs (NSAIDs) inhibit the proliferation of mucosal cells that normally leads to healing of gastric ulcers a microdissection technique was used to quantify mitosis in gastric glands at the ulcer edge in relation to that in the adjacent mucosa. The regeneration index thus obtained of the ulcer edge was greater in the 9 subjects with gastric ulcers not taking NSAIDs (mean index 3.1 [SEM 0.61]) than that in the 8 patients taking NSAIDs (index 1.49 [0.16]). In rats in which gastric ulcers were produced with a cryoprobe, the ulcers were larger and slower to heal in those receiving indomethacin than in controls; also, immunohistochemical staining indicated significantly fewer mitotic cells in glands adjacent to the ulcer in indomethacin-treated rats (8 mitoses [SEM 3]) than in control animals (25 [5]). The prostaglandin E1 analogue misoprostol reversed the inhibition of healing and substantially restored the proliferative rate in the animals. Inhibition of epithelial cell division normally involved in gastric ulcer healing would contribute to the high prevalence of gastric ulcer during NSAID therapy.

Adult↗
PubMed1989

Identification of the origin of cells in human basal cell carcinoma xenografts in mice using in situ hybridization.

In an attempt to identify more clearly the origin of cells in human basal cell carcinoma xenografts in mice, paraffin and frozen sections were subjected to in situ DNA hybridization with biotin labelled human and murine DNA probes. Human skin and mouse skin sections were used as controls. As expected, the implanted epithelium reacted with the human DNA probe and the surface epithelium and most of the stromal cells reacted with the murine probe. However, the stroma immediately surrounding the implanted epithelium contained cells of human origin mixed with murine cells. Occasional murine cells (presumed inflammatory) were present in the human implanted epithelium. Assessment showed no correlation between the degree of differentiation of the implanted epithelium and the ratio of human/murine cells in the contiguous stroma. This technique provides a sensitive test for identifying human cells in xenografts and may be useful in assessing the role of stromal cells in the differentiation of a variety of carcinomas.

Animals↗
PubMed1988

Response of the benign hypertrophied prostate to treatment with an LHRH analogue.

Twenty patients with outflow tract obstruction secondary to benign prostatic hypertrophy were treated with an LHRH analogue, buserelin, for up to 6 months. Despite maintaining castrate levels of testosterone and achieving a significant reduction in tissue levels of dihydrotestosterone, no significant improvement was seen in flow rate or residual volume.

Buserelin↗
PubMed1988

Clonal rearrangement of the T-cell receptor gamma gene associated with a bizarre lymphoproliferative syndrome.

Investigations in an unusual patient with prolonged fever, fat necrosis and haemorrhagic tendency showed widespread histiocytic phagocytosis in fat and liver biopsy specimens. Lymph nodes were also infiltrated by morphologically normal T lymphocytes predominantly expressing the OKT4 antigen. Analysis of lymph node DNA using immunoglobulin and T-cell receptor (TCR) probes showed rearrangement restricted to the gamma TCR gene combined with polyclonal beta TCR gene rearrangements, thus providing evidence of a unique lymphoproliferative disorder of T cells. The patient displayed a striking response to cytotoxic chemotherapy.

DNA↗