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Biomedical subjects

D Hopwood

Publications and source records attributed to D Hopwood.

At least 19 recordsLinked to original sources
PubMed1994

Secretory and absorptive activity of oesophageal epithelium: evidence of circulating mucosubstances.

The space between the oesophageal basal and prickle epithelial cells appears empty by standard ultrastructural preparative techniques. Fixation of human oesophageal biopsies with a variety of agents, including tannic acid, glutaraldehyde-lysine, cetylpyridinium chloride and Ruthenium Red shows that this space is filled with mucosubstances, some free, some attached to the cells as a glycocalyx. There is evidence that this material is secreted constitutively by the basal and prickle cells. This secretion may be changed or blocked by incubating oesophageal biopsies in the presence of colchicine or dinitrophenol. Incubation at 16 degrees C has the same effect. Absorption from the intercellular space may be followed using the fluid phase marker, horseradish peroxidase. Early endosomes may also be shown by their acid phosphatase activity. Incubation of biopsies at 20-22 degrees C allows early endosomes to accumulate material, but not pass it on the late endosomes.

Absorption↗
PubMed1992

Membranous expression of carcinoembryonic antigen (CEA) in the normal cervical squamous mucosa.

Using a panel of polyclonal and monoclonal antibodies to CEA-related antigens in paraffin-processed cervical biopsies, CEA and NCA expression has been demonstrated on the cell membrane of normal mature cervical squames. Cytofluorimetry of disaggregated cervical squames confirmed membranous expression and immunogold labelling of ultrathin cryostat sections localized CEA to the glycocalyx and to within cytoplasmic membrane-bound vesicles of mature squames. Immunoblotting of cervical tissue showed that most of the CEA reactivity was expressed as a glycoprotein of molecular weight around 180 k, probably CEA itself. Localization of the CEA to the cell membrane of mature cervical squames suggests a key role for these antigens in maintaining the integrity of the squamous mucosa, through the putative function of an adhesion molecule.

Carcinoembryonic Antigen↗
PubMed1992

Flow cytometry of oesophageal mucosal biopsies; epidermal growth factor receptor, and CD15.

Flow cytometry may be used to examine the properties of single or isolated cells. We have shown that it is possible to disaggregate and label oesophageal epithelial cells for two surface markers, CD15 and epidermal growth factor receptor. We have previously demonstrated these markers in oesophageal squamous cells using immunoperoxidase techniques. These labelled disaggregated cells could then be measured by flow cytometry.

Adult↗
PubMed1992

Cytokeratin expression in oral exfoliative cytology: effect of temperature and fixation.

The identification of keratin expression within oral cytology may be useful in the diagnosis of clinically suspicious oral mucosal lesions. There may be wide variation in the temperature at which such smears are stored, prior to processing. Conventionally, rapid fixation or storage at low temperatures is recommended to preserve kertin expression within tissue biopsies. No previous study has assessed whether this is true for oral cytology. Smears were taken from clinically normal buccal mucosa. For each temperature assessed (-70, -40, -22, +5, +20 and +26 degrees C), one smear was spray-fixed (Vale Smear Fix) and one air-dried, prior to storage for 4 days, and then staining with the pan-epithelial antikeratin antibody, LP34. Preservation of keratin expression was assessed as either weak (zero to few positive cells) or strong (most cells positive). The results were analysed using logistic regression with the statistical modelling package, GLIM. Over the range of temperatures studied, spray fixation did not appear to improve the identification of keratin expression. Although the best preservation was obtained at lower temperatures, keratin expression was still adequate after 4 days at 20 degrees C. Hence, a delay in processing of 4 days would still allow detectable expression in oral exfoliative cytology even at room temperature.

Adolescent↗
PubMed1992

Growth regulatory peptides in gastric mucosa.

1. Epidermal growth factor and the related peptide transforming growth factor alpha have been implicated in the stimulation of gastric mucosal proliferation. We assessed the immunohistochemical distribution of these peptides and their receptor, epidermal growth factor receptor, in mucosa from the antrum and body of the stomach from 28 patients. Twenty-three of the 56 biopsies were histologically normal (12 antrum and 11 body), whereas the other 33 showed varying degrees of inflammation. 2. Epidermal growth factor, transforming growth factor alpha and epidermal growth factor receptor had maximal density of distribution on the apical surfaces of the superficial epithelial cells, but were also expressed to a lesser extent on neck and body cells of the glandular tissue (P less than 0.05). We also demonstrated that epidermal growth factor expression was greater in the epithelial cells of inflamed mucosa than in those of normal mucosa (P less than 0.05). 3. We assessed mucosal proliferation by the Ki-67 labelling index. Ki-67-positive cells were found predominantly in the neck area of the glands and were more frequent in glandular antral tissue than in body glandular tissue (P less than 0.05). Expression of epidermal growth factor receptor in the neck and isthmus cells had a significant correlation with the Ki-67 labelling index (P less than 0.05). 4. We conclude that epidermal growth factor and epidermal growth factor receptor may be important in the adaptation of gastric mucosa to inflammation.

Epidermal Growth Factor↗
PubMed1992

Epidermal growth factor in the oesophagus.

Epidermal growth factor (EGF) has been implicated in mitogenesis and oncogenesis in the gastrointestinal tract. To determine the role of EGF in oesophageal disease, its quantity and distribution in the oesophageal mucosa of control subjects and patients with oesophageal disease were studied. Oesophageal biopsy specimens, taken 20-40 cm from the incisors in 72 patients, were graded histologically and adjacent specimens were taken for immunohistochemical analysis of the distribution of EGF. In patients with Barrett's columnar lined oesophagus, specimens were also taken from the gastric cardia for comparison. Twenty two biopsy specimens showed oesophagitis, 20 Barrett's mucosa, and 30 were histologically normal. EGF was found in the capillary endothelium of the normal oesophageal papillae and basal mucosa. Significantly more EGF positive papillae were found in the normal mucosa (81%) than in the inflamed mucosa (42%) (p < 0.001). The 20 patients with Barrett's mucosa showed abnormal expression of EGF in 25% of the isthmus and superficial epithelial cells. This study has shown that EGF is found only in the endothelial cells of the capillaries of the normal oesophageal mucosa and that the peptide is detectable significantly less frequently than normal in the inflamed oesophageal mucosa. EGF is also abnormally present, in large quantities, in the cytoplasm of the epithelial cells of Barrett's mucosa compared with gastric mucosa.

Adult↗
PubMed1992

Epidermal growth factor receptors in the oesophagus.

The quantity and distribution of epidermal growth factor receptors (EGF-R) in oesophageal mucosa was studied in the oesophagus in order to determine its role in oesophageal disease. Fifty five biopsies were taken from different levels of the oesophagus in 25 consecutive patients undergoing endoscopy. Another group of eight patients with histologically proven Barrett's oesophagitis had a biopsy taken from the area of columnar lined oesophagus. A peripheral, membranous pattern was seen predominantly confined to the basal and immediately suprabasal cells in all of the first group of patients. In the superficial cells a few granular cytoplasmic structures were positive. All patients with Barrett's oesophagitis showed EGF-R staining of the surface epithelium. A computerised planimeter was used to determine the proportion of stained areas of squamous cells which were expressed as a percentage of the total area of squamous cells. The difference in the area of cells stained for EGF-R between normal and inflamed oesophageal mucosa (29.5% and 43.1% respectively) was significant (p less than 0.001).

Adult↗
PubMed1992

Proliferating cell nuclear antigen in oesophageal diseases; correlation with transforming growth factor alpha expression.

This study was designed to correlate mucosal proliferation in Barrett's oesophagus with expression of a growth promoting peptide, transforming growth factor alpha (TGF alpha). Oesophageal mucosa was studied from 50 patients with oesophageal disease who had been treated by oesophagectomy. Histological analysis showed a range of oesophageal pathology - 18 patients had gastric type Barrett's mucosa, 18 had intestinal type Barrett's mucosa, and 14 had oesophageal adenocarcinomas. Sections were stained immunohistochemically for proliferating cell nuclear antigen (PCNA) (an index of cellular proliferation) and TGF alpha. PCNA immunostaining was seen mainly in the basal cells of the neck/foveolar epithelial compartment of the glands in Barrett's oesophagus. However, in mucosa with high grade dysplasia, the proliferative compartment extended upwards into the superficial layers of the glands. At least 2000 cells were counted in each patient to determine the proportion with PCNA immunoreactivity (PCNA labelling index). The labelling index was highest in adenocarcinoma (25%) and in Barrett's intestinal type mucosa with high grade dysplasia (26%) compared with intestinal type mucosa with no significant dysplasia (20%) and Barrett's gastric type mucosa (12%). There was a significant positive correlation between PCNA labelling indices and TGF alpha expression in Barrett's mucosa (p less than 0.01). In glands showing high grade dysplasia, TGF alpha immunoreactivity was seen in the same regions of the glands as PCNA immunoreactivity, indicating the possibility of involvement of TGF alpha in (pre) neoplastic proliferation in Barrett's oesophagus.

Adenocarcinoma↗
PubMed1992

Oncogenes and onco-suppressor gene in adenocarcinoma of the oesophagus.

While the activation of the proto-oncogenes has been implicated in the development and progression of cancer of many tissues, the role of oncogenes in the development of oesophageal adenocarcinoma has not been defined. Fifteen patients who had undergone resection for oesophageal adenocarcinoma and 15 who had undergone oesophagectomy or biopsy for Barrett's oesophagus were studied. The latter patients also had adjacent normal gastric mucosa biopsied for comparison with the metaplastic oesophageal mucosa. The mucosal samples were snap frozen and subsequently stained with monoclonal antibodies to the following oncogene associated proteins; c-erbB2 (neu and CE-1) (external domain), c-erbB2 (NCL-CB11) (internal domain), c-src, c-ras, c-myc, c-fos, c-jun, and the onco-suppressor gene--p53. All tumours were well or moderately differentiated adenocarcinomas arising from the lower third of the oesophagus. Eleven specimens showed strong membraneous staining with both c-erbB2 (neu) and c-erbB2 (CBL-CB11). Seven specimens showed strong nuclear staining with p53 onco-suppressor gene. Three specimens were positive for c-ras and c-src, and two were positive for c-jun. In Barrett's epithelium, nine specimens were positive for c-erbB2 (neu and CB11), three were positive for c-src, two were positive for c-ras and c-jun, and one was positive for c-fos. Two of the gastric mucosal biopsy specimens expressed c-erbB2 weakly but no other oncogenes were found. The frequency of positive staining for c-erbB2 is very high, compared with the expression of these genes in other tumours. It is also concluded that errors in the onco-suppressor gene p53, and especially in the external and internal domains of c-erbB2, which is also often expressed in Barrett's mucosa, may be implicated in the development of adenocarcinoma of the oesophagus.

Adenocarcinoma↗
PubMed1992

Flow-cytometric analysis of growth-regulatory peptides and their receptors in Barrett's oesophagus and oesophageal adenocarcinoma.

The conventional assessment of the premalignant potential of Barrett's oesophagus is unsatisfactory. However, it has recently been shown that abnormalities of growth-regulatory peptides and their receptors may be important in the pathogenesis of this condition. In an attempt to improve the diagnostic and prognostic criteria we have studied 21 consecutive patients with Barrett's oesophagus and 7 others with adenocarcinoma of the oesophagus. In each patient biopsy specimens were taken from the columnarlined oesophagus or the adenocarcinoma and from the gastric cardiac mucosa for routine histologic evaluation. Immediately adjacent specimens were taken from both the Barrett's mucosa or adenocarcinoma and from the gastric mucosa for flow-cytometric study. The latter samples were disaggregated and labelled with antibodies to epidermal growth factor (EGF), transforming growth factor alpha (TGF-alpha), and epidermal growth factor receptor (EGF-R). The flow cytometer selected cells labelled with each antibody and expressed them as a percentage of the total number of disaggregated cells (average, 5500 cells). Epidermal growth factor receptors were expressed in a greater number of cells from Barrett's mucosa, with the intestinal type or those with dysplasia, than in gastric cardiac mucosa (p less than 0.05). All seven adenocarcinoma had many more cells expressing EGF, TGF-alpha, and EGF-R than normal gastric mucosa (p less than 0.01). We conclude that flow-cytometric evaluation of EGF-R can help in the understanding of the pathogenesis of Barrett's oesophagus.

Adenocarcinoma↗
PubMed1992

Glycogen storage disease diagnosed in adults.

Glycogen storage diseases are usually identified in childhood. We present the clinical, biochemical and histological features of 10 patients first diagnosed in adult life. Five had glycogen storage disease type 1a, one type 1c, two type IX, and in two patients there were previously unreported abnormalities of hepatic glucose-6-phosphatase system activity. Of the latter, one patient had an inhibitor of liver glucose-6-phosphatase (pseudo-1b glycogen storage disease) the other having abnormal glucose-6-phosphatase activity and microsomal pyrophosphate transport. A glucagon test is suggested as a useful screening procedure. Glycogen storage disease should be considered in adults with symptoms suggesting hypoglycaemia.

Adolescent↗
PubMed1992

Adverse influence of fibrin sealant on the healing of high-risk sutured colonic anastomoses.

The effect of fibrin glue sealing on sutured colonic anastomoses was studied using a 'high-risk' colon anastomosis model in the rat. Animals (n = 104) were randomized to have their sutured anastomosis sealed with fibrin glue or left untreated. They were assessed clinically until they were killed on the fourth day after surgery when contrast radiology, detailed post-mortem examination, anastomotic bursting pressure (ABP) and assessment of adhesion formation were performed. The clinical outcome was worse in the glued group (toxic or death from sepsis: 18 versus seven in the non-glued group; P = 0.0354), which also showed a significantly higher moderate to major leak rate (17 versus two in the non-glued group; P = 0.0009). The median ABP was significantly higher in the glued anastomosis group (96 versus 68 cmH2O in the non-glued group; P = 0.0367). Excessive perianastomotic adhesion formation was significantly greater in the glued group. Microscopic examination showed an extremely intense inflammatory reaction in the glued anastomoses compared with that in the untreated group. These results indicate that sealing of a sutured anastomosis with fibrin glue containing an antiproteinase impairs healing the of anastomotic wound, probably by resisting the ingrowth of vascular granulation tissue during the early stages of repair.

Anastomosis, Surgical↗
PubMed1991

Mucosal function after ileal mucosal fenestration and colonic autotransplantation.

A method of small bowel mucosal augmentation called ileal mucosal fenestration and colonic autotransplantation (IMFCA) was devised and tested in pigs. In this technique, a vascularized mucosal graft was harvested from a 12-cm ileal loop, fenestrated by serial incision and then expanded to 20 cm. A 20-cm colonic loop was isolated and surgical mucosectomy was carried out. The fenestrated ileal mucosal graft was then autotransplanted into the prepared colon and the resulting composite structure was exteriorized as a Thiry-Vella loop. With this technique, ileal mucosal fenestrations healed by lateral epithelial in-growth, giving a new mucosal continuum within the recipient colon. At 60 days after surgery, the surface area of transplanted mucosa exceeded that within the original ileal loop by approximately 85 per cent. At this time, the transplanted mucosa had morphology and capacity for Na(+)-dependent glucose transport which were indistinguishable from those of control ileal mucosa.

Animals↗
PubMed1991

Leakiness of gastric superficial and foveolar cells. A quantitative electron microscopic study using tannic acid.

Two adjacent antral biopsies were taken endoscopically from 41 patients attending a clinic for the investigation of upper gastrointestinal tract symptoms. One was processed for histopathological grading and assessment of the Helicobacter pylori by light microscopy. The other was fixed in tannic acid, which demonstrates cell leakiness, and processed for electron microscopy. On each grid, the light (electron lucent) and dark (electron dense-leaky) gastric superficial and foveolar cells away from mechanical trauma of biopsy were counted, along with the number of H. pylori which were in contact with the epithelial cells. There was a significant relationship between histological grade of gastritis and the extent of electron microscopic damage, i.e., the degradation of normal to leaky cells and the number of H. pylori per leaky cell. If the patients were divided into two groups with minimal and maximal gastritis and compared against each other, then there was a significant difference between the two groups with respect to surface cell damage, polymorphs per unit area, the number of glands invaded by polymorphs, light/dark cells, Helicobacter grades assessed light microscopically or totals counted in contact with epithelial cells by electron microscopy, the number of Helicobacter per cell, and the age of the patients. There was no difference between the two groups on their endoscopic appearances or treatment with H2 blockers or NSAIDS.

Adolescent↗
PubMed1991

Uptake of horseradish peroxidase by human oesophageal explants over 24 h.

Human oesophageal biopsies, endoscopically and histologically normal, were incubated in Ham's F10 for periods up to 24 hours in the presence of horseradish peroxidase. The fluid phase marker was taken up most avidly by the prickle cells but to a lesser extent in the functional layers and by basal cells. Endocytosed markers proceeded to multivesicular bodies (segrosomes). Horseradish peroxidase was later deposited in lysosome-like structures and also in the Golgi apparatus. The lesser uptake by the functional cells may represent reduced access of the marker to the cells due to the intercellular barrier.

Cell Membrane↗
PubMed1991

Microencapsulation of human cells: its effects on growth of normal and tumour cells in vitro.

The growth kinetics of established human colorectal tumour cell lines (HT29, HT115 and COLO 320DM) and human diploid fibroblasts (Flow 2002) were studied in conventional culture and in microcapsules formed from alginate-poly(L-lysine)-alginate membranes. The tumour lines grew rapidly in microcapsules but, in the case of the substrate-adherent lines HT29 and HT115, only after a prolonged lag phase. This phase was reduced by serial passage in microcapsules. The anchorage-independent line COLO 320DM showed no lengthening in lag phase. Microencapsulated fibroblasts underwent negligible growth but remained viable. Some evidence for functional differentiation (microvilli, cell-cell junctions) of the tumour line HT115 within the microcapsules was observed. We conclude that the use of microcapsules provides an alternative system with some advantages for the study of human cancer and its metastases in vitro.

Cell Adhesion↗