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Biomedical subjects

A Wee

Publications and source records attributed to A Wee.

At least 55 records · Page 3Linked to original sources

Trivalent metal ions in the prevention of calcification in glutaraldehyde treated biological tissues. Is there a chemical correlation?

The influence of chemical factors on trivalent metal ions in the prevention of calcification of glutaraldehyde treated biological tissue has been explored. The results indicate that the chemical link lies in the hard character of the trivalent metal ions. Metal ions with the hardest character appear to have the best chance of reacting with oxygen atoms of the phosphate groups at nucleation sites of hydroxyapatite. This disrupts the nucleation and thus prevents calcification in glutaraldehyde treated biological tissue.

Animals↗

Uncommon presentation of typhoid fever: a case report.

A 24-year-old Chinese woman was admitted for cholestatic jaundice following a short history of fever associated with headache and diarrhoea. She had mild hepatomegaly. Initial laboratory investigations were non-contributory. A percutaneous liver biopsy revealed inflammatory changes more in keeping with a systemic infection than a primary hepatitic problem. Repeat blood and stool cultures finally grew salmonella typhi. Jaundice is a rare manifestation of typhoid fever; it occurs in less than one-third of patients with hepatomegaly. Such a presentation may mimic primary hepatic infections. Awareness of this rare occurrence in typhoid fever would help in early diagnosis and therapy.

Adult↗

Sclerosing haemangioma of lung--case report with histologic, immunohistochemical and ultrastructural correlation.

We report a case of a large sclerosing haemangioma of the lung that was found incidentally on roentgenography of an asymptomatic woman presenting for routine health screening. Computed tomographic scan showed a well-defined "coin" lesion with peripheral foci of calcification. The lesion had a variegated histological appearance comprising four major patterns--solid, papillary, haemorrhagic and sclerotic. There appeared to be two populations of cells--distinct round cells with abundant clear cytoplasm constituting the solid component and uniform cuboidal cells with small, dark nuclei lining irregular spaces. Positive immunohistochemical staining for cytokeratin and epithelial membrane antigen, and the ultrastructural demonstration of epithelial characteristics and electron-dense bodies showed that the proliferating cells had features in keeping with type 2 pneumocytes. This is a benign condition and the prognosis is excellent.

Adult↗

Augmentin-induced cholestatic jaundice--a case report.

A case of cholestatic jaundice following treatment with Augmentin is reported. The awareness of hepatotoxicity due to drug should help to avoid unnecessary invasive procedures in the evaluation of this reversible condition.

Acute Disease↗

Peliosis hepatis: a case report.

A 54-year-old man who presented with marked hepatomegaly and a liver scan suggestive of an infiltrative malignancy was found to have peliosis hepatis caused by androgenic steroids. A detailed and repeated drug history is necessary for making the correct diagnosis. Withdrawal of the offending drug is indicated and may result in reversal of this serious form of hepatic toxicity.

Androgens↗

Helicobacter pylori and gastric cancer: correlation with gastritis, intestinal metaplasia, and tumour histology.

This study aimed to examine the association between Helicobacter pylori, histological gastritis, and intestinal metaplasia in gastric cancers of different histological types. A total of 169 gastrectomy specimens received in one pathology department were studied. Altogether 156 were adenocarcinomas (intestinal type 87, diffuse type 50, mixed type 19). Gastritis occurred in 137 of 163 body specimens (84%) and in 126 of 131 antral specimens (96%). Its presence was unrelated to tumour histology. Atrophic gastritis was more common in both body and antral mucosa in intestinal type compared with diffuse type carcinoma. This was also true for intestinal metaplasia of the body, but not of the antral mucosa. H pylori was present in 101 of 163 (62%) body specimens and 56 of 131 (43%) antral specimens. In intestinal type carcinoma, H pylori was found in 52/84 (62%) body specimens and in 24/70 (34%) antral specimens, while the corresponding figures for diffuse type carcinoma were 29/48 (60%) and 17/38 (45%) respectively. Tumour histology therefore had no influence on the occurrence of H pylori. Tumour site had no effect on the presence or absence of gastritis, atrophic changes, intestinal metaplasia, or H pylori. While both H pylori and gastritis are associated with gastric cancer, the association is unrelated to tumour histology and may not be a causal one.

Adenocarcinoma↗

Association of Helicobacter pylori with HLA-DR antigen expression in gastritis.

AIMS: To assess the association between Helicobacter pylori-associated gastritis and HLA-DR antigen (class II antigen) expression. METHODS: Fifty endoscopic gastric biopsy specimens were studied for the presence of H pylori, degree and type of inflammation, and for HLA-DR antigen expression in the epithelium. The cases were chosen to represent different categories: inflamed gastric mucosa with (n = 13) and without (n = 20) H pylori, and non-inflamed mucosa (n = 17). RESULTS: The antigen was aberrantly expressed in the antral mucosal epithelium in 11 of 12 cases (92%) with acute-on-chronic gastritis when H pylori was also present. It was present in the antrum in only seven of 18 H pylori negative cases (39%) with acute-on-chronic/chronic gastritis. One of three cases of acute gastritis and three of seven cases of chronic gastric erosions (non-inflamed category) showed positive staining. Generally, there was more staining in the antral than body mucosa and in the surface/foveolar epithelium than in the glands. No aberrant HLA-DR antigen expression was found in the 10 cases of normal gastric mucosa examined. CONCLUSIONS: These findings suggest that H pylori may have a role in the induction of class II HLA antigen expression in chronic gastritis and lend support to the view that these organisms may be responsible for part of the inflammatory response.

Acute Disease↗

Expression of HLA-DR antigen in different histological types of gastric polyp.

AIMS: To study the expression of HLA-DR antigen in the different histological types of gastric polyps. METHODS: Ninety five cases of gastric polyps were histologically classified and examined for the presence of Helicobacter pylori, and for degree and type of inflammation. Further sections were stained immunohistochemically for HLA-DR antigen expression in the epithelium using a monoclonal antibody that was reactive to formalin-fixed paraffin wax embedded tissue. RESULTS: HLA-DR antigen was expressed in all of the inflammatory polyps studied (20/20), and in most hyperplastic (12/16) and adenomatous (4/6) polyps. Only a few fundic gland polyps (8/51) stained positively for HLA-DR antigen. Gastric polyps seem to have a greater tendency to express HLA-DR antigens than non-polypoid gastric mucosa, even after considering the factors that may affect HLA-DR antigen expression, such as inflammation and the presence of H pylori. CONCLUSIONS: Growth disturbances/polyp formation may be associated with increased HLA-DR antigen expression.

Adolescent↗

Relief from chronic pelvic pain through surgical lesions of the conus medullaris dorsal root entry zone.

Dorsal root entry zone (DREZ) lesions are effective in treating specific pain syndromes, most notably post-brachial plexus avulsion. There is limited experience, however, with lesions in the conus medullaris. We review the case of a patient having pelvic pain and urinary retention who failed to improve despite multiple prior interventions. Her pain was completely relieved after DREZ lesions were placed bilaterally at S2, S3, S4 and S5. The intraoperative sensory and motor evoked potential monitoring used to define the level is described in detail.

Action Potentials↗

Helicobacter pylori and gastric acid output in peptic ulcer disease.

Helicobacter pylori is associated with peptic ulcer, and a causal relationship has been postulated. We investigated the association between Helicobacter pylori and gastric acid output. Two hundred forty-one patients were studied: 173 with duodenal ulcer, 51 with gastric ulcer (41 corpus, 10 prepyloric), and 17 with combined gastric and duodenal ulcer. In 194 patients (80%), Helicobacter pylori could be demonstrated histologically from gastric antral biopsies. The presence or absence of Helicobacter pylori was not influenced by age, sex, or use of tobacco or analgesics. Patients with duodenal ulcer or combined gastric and duodenal ulcer had similar gastric acid outputs irrespective of the presence or absence of Helicobacter pylori. However, gastric ulcer patients with Helicobacter had higher basal and maximal acid outputs when compared to patients without Helicobacter (mean basal output: 4.1 mmol/hr vs 2.4, P less than 0.05; mean maximal output 19.5 mmol/hr vs. 14.4, P less than 0.05). Although Helicobacter pylori is associated with both gastric ulcer and duodenal ulcer, its significance may be different in the two diseases.

Duodenal Ulcer↗

Cytological diagnosis from fine needle aspiration biopsy of the liver.

One hundred and six fine needle aspiration biopsies (FNAB) of the liver were performed on 99 patients to rule out hepatic malignancy. Biopsies were performed with CT guidance (60), ultrasonography (40), fluoroscopy (3), by direct palpation (2) and intra-operatively (1). The smears and cell blocks were reviewed and the cytologic diagnoses were made after clinicopathologic correlation. Eight cases were excluded (six non-diagnostic and two mislaid). Fifty-two were positive, 2 suspicious and 44 negative for malignancy. There were no false positive results. The sensitivity for malignancy was 84.4%, the specificity was 100% and the predictive value of positive results was 100%. The false negative rate was ten out of 44 cases (22.7%). Of the malignant aspirates, there were 27 hepatocellular carcinomas, 21 metastases and four carcinomas of unknown histogenesis. Common benign lesions included abscesses, cysts, cirrhosis and steatosis. For FNAB to be an effective diagnostic procedure, adequate representative sampling, cell block preparation for appraisal of histological architecture and experience in cytomorphologic interpretation are necessary to increase yield and enhance precision of diagnosis.

Adult↗

Chronic hepatitis B infection in Singapore.

Four hundred and four patients (273 men, 131 women) aged 3 to 85 years with chronic Hepatitis B virus (HBV) infection seen during a five year period were analysed. At presentation, 177 patients (44%) were Hepatitis B e Antigen (HBeAg) positive (mean age 32 years) and 217 patients (54%) were anti-HBe-positive (mean age 40 years). Ten patients (2%) were negative for HBeAg and anti-HBe. Serum HBV-DNA was detected in 169 patients (42%). 85% of the HBeAg-positive patients had detectable serum HBV-DNA and 9% of the HBeAg-negative patients were positive for serum HBV-DNA. The mean serum Alanine amino-transferase (ALT) and Aspartate amino-transferase (AST) levels were higher in HBeAg-positive patients (75 and 52 iu/l) than in HBeAg negative patients (46 and 37 iu/l) (P less than 0.001). Liver biopsies were performed in 135 patients. Fifty-three (39%) had minimal changes, 61 (45%) chronic hepatitis (CPH, CLH & CAH) and 21 (16%) cirrhosis. There was no significant difference in the histologic distribution between HBeAg-positive and HBeAg-negative groups. Two hundred and fifty eight patients were followed up for a mean duration of 2 years (range 3 to 108 months). The cumulative probability of clearing HBeAg at the end of the first, second and third year were 14%, 16% and 18% respectively. Of these, the cumulative probability of developing anti-HBe over one, two and three years were 8%, 9% and 11% respectively. Reversion to HBeAg occurred in 1.5% of patients who were HBeAg-negative at presentation and 11% of HBeAg-positive patients who cleared HBeAg.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

An in vitro assessment of human fetal pancreatic islets of Langerhans in culture.

The human fetal pancreas is a potential source of islets for transplantation into insulin-dependent diabetic patients. In this study, 35 human fetal pancreas obtained from prostaglandin-induced abortions (12-26 weeks gestation), were placed in culture to determine their capacity to secrete insulin over 30 days. Culture media were sampled twice weekly for insulin and histology was performed serially. Of the 35 pancreases cultured, six were lost due to bacterial contamination, five discarded due to undetectable levels of insulin in culture, nine are still under study, whilst 15 pancreases have been cultured for one month, and insulin studies completed. Three patterns of insulin release were observed: (a) progressive decline (n = 6), indicating non-viable tissue at the onset; (b) delayed decline, indicating significant tissue damage before organ culture (n = 5); and (c) insulin production in vitro over 30 days (n = 4), with viable islets detected histologically. Factors such as gestational age and cold ischaemia time did not correlate with the pattern of insulin secretion observed. This was probably due to a more important variable, not easily assessed, of the period of intrauterine (warm) ischemia. These data suggest: (1) that a small number of fetal pancreases procured from prostaglandin-induced abortuses do yield islets which remain viable in culture over 30 days, and (2) the functional status of islets can be monitored in vivo by measuring insulin secretion, thereby providing a means of identifying tissue suitable for transplantation.

Culture Techniques↗

A study of the xenogeneic response in an isolated liver perfusion circuit--preliminary observations.

An isolated liver perfusion circuit was developed to study the xenogeneic reaction of human blood to porcine liver, and investigate the feasibility of using such a system for liver dialysis in fulminant hepatic failure. Three experimental groups were studied: a control group where pooled porcine blood was perfused through pig liver (n = 12), a xenogeneic group where banked human blood was perfused through porcine liver (n = 23), and a modified xenogeneic group where decomplemented human blood was perfused through porcine liver (n = 4). The following parameters of liver function were assessed: liver function tests, serum electrolytes, bile and ascites production. In addition, liver histology was assessed at the start and completion of each perfusion experiment. Control experiments established that the use of low perfusion pressures (mean inlet pressure of 29.5 +/- 7.4 mmHg), and low haematocrit of 20.5 +/- 8.9% (n = 14), enabled five hour perfusions to be consistently achieved with maintenance of normal acid base and electrolyte balance. Bile production over 5 hours was 18.8 +/- 8.0 ml in controls (n = 5) and 17.0 +/- 6.7 ml in the xenogeneic (human-pig) circuit (n = 11) (NS). Ascites production was 235.8 +/- 157.3 ml/hr in controls (n = 5) and 205 +/- 142.0 ml/hr in the xenogeneic circuit (n = 7) (NS).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗