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Biomedical subjects

J Ho

Publications and source records attributed to J Ho.

At least 109 records · Page 6Linked to original sources
PubMed1993

CEA tissue staining in colorectal cancer patients--correlation with plasma CEA, histology and staging.

To study the expression of tissue carcinoembryonic antigen (CEA) by immunoperoxidase staining in colorectal adenocarcinomas and its relation with preoperative serum CEA and clinicopathological parameters, we studied 85 unselected patients who underwent resective surgery for colorectal adenocarcinomas and were followed up for a mean of 66 mths. All tumors except 2 showed positive staining for CEA. The staining pattern was classifiable into 4 types: apical, cytoplasmic, basolateral and stromal, according to the predominant sites of staining. We found a significant positive correlation between tissue CEA staining pattern and preoperative plasma CEA. Plasma CEA levels were higher when tumor cell staining extended to basolateral regions of the cells and into stromal tissues rather than restricted to apical and cytoplasmic regions (p = 0.012). Furthermore, tissue CEA staining also correlated positively with vascular invasion by tumor cells (p = 0.046), with basolateral and stromal types associated with more frequent vascular invasion than apical and cytoplasmic types. This was in contrast to the preoperative CEA which did not correlate with vascular permeation. We speculate that tissue CEA staining is useful in indicating possible vascular invasion even at early stage whereas vascular invasion by a larger tumor bulk or even tumor metastases may be necessary to produce an increased plasma CEA level that is detectable. On the other hand, preoperative plasma CEA had a strong, positive relationship with tumor stage and mortality (p < 0.001 for both). Preoperative CEA was higher in tumors showing moderate and poor differentiation, although it did not reach statistical significance (p = 0.068), whereas tissue CEA staining had no correlation with tumor differention.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenocarcinoma↗
PubMed1993

Primary malignant fibrous histiocytoma of the spleen and liver--a case report.

Primary malignant fibrous histiocytoma of the spleen is extremely rare. Only four cases have been reported so far. We report a case of primary malignant fibrous histiocytoma of the spleen and liver presenting like multiple liver and splenic abscesses. The controversy surrounding its histogenesis is discussed.

Aged↗
PubMed1992

A randomized comparative trial of the MLCu375, TCu220C, steel ring and uterine cavity-shaped IUDs.

The Stainless Steel Ring, Uterine Cavity-Shaped Device, TCu220C and MLCu375 IUDs were evaluated in a randomized trial of 1536 women in Guangdong Province, China. The first-year continuation and expulsion rates were significantly lower (p less than 0.05) for the latter 3 IUDs than for the Stainless Steel Ring. The first year pregnancy rates for the MLCu375 (0.76 per 100 women) and TCu220C (1.2 per 100 women) were significantly lower (p less than 0.05) than those of the other two devices (6.1 and 4.1 per 100 women). The results of the study show that the MLCu375 and TCu220C are the most suitable IUDs for women in Guangdong Province.

Adult↗
PubMed1992

Microvascular changes in rat glomeruli as a consequence of small differences in selenium exposure.

This paper evaluates the effect of small differences in selenium exposure, within the safe range, on the glomerular vascular tufts of rats fed high-sucrose diets. In the first experiment male Wistar rats were housed in galvanized cages and were provided sucrose-based diets to induce a mild chronic insult to the microcirculation. One group of rats received the diet prepared to contain 0.10 mg Se/kg and another group 0.21 mg Se/kg. To assure that the galvanized metal cages were not influencing the results of the experiment this protocol was repeated in a second experiment wherein rats were housed in stainless steel cages. The levels of Se used supported normal activity of the long-term indicator of Se sufficiency, erythrocyte glutathione peroxidase. In both experiments rats fed diets containing 0.21 mg Se/kg had larger Bowman's capsules (P < 0.01) and vascular tufts (P < 0.01). Vascular tufts from these rats also contained a higher proportion of open capillary lumen (P < 0.01), contained less cytoplasmic and extracellular material (P < 0.001), and had larger nuclei (P < 0.001) than those fed 0.10 mg Se/kg. A third study was designed to determine if the selenium-dependent differences in nuclear size were indicative of this being a site of incorporation. Year-old rats subjected to the same protocol as those in the second experiment were given 75Se, by injection into the femoral vein, to label the sites of incorporation. Glomeruli were purified and subjected to subcellular fractionation. Ninety percent of the radioactivity was associated with the crude nuclear fraction. Purification of the crude nuclear fraction demonstrated that the radioactivity was associated with the nuclei.

Animals↗
PubMed1992

"Serpentine heart". Direct observation of the human heart during profound hyperkalemia.

We observed cardiac contractility in a patient who had inadvertently received a massive overdose of potassium chloride during open heart surgery. Slowly advancing waves of contraction were present while the surface electrocardiogram showed the sine wave configuration typical of severe hyperkalemia. This is the first report of such an observation and may serve to promote proper diagnosis and treatment of similar cases.

Coronary Artery Bypass↗
PubMed1992

Regulation of prodynorphin gene expression in the hippocampus by glucocorticoids.

The regulation of prodynorphin gene expression by glucocorticoids in the hippocampus was examined in rats that were adrenalectomized (ADX) either 7, 30, 60 and 90 days prior to sacrifice. Peptide levels in the hippocampus of ADX rats were determined by radioimmunoassay and immunocytochemistry. Prodynorphin (PDYN) mRNA was measured by Northern blot analysis and in situ hybridization. A time-dependent decrease in dynorphin A(1-8)(DYN) levels in the hippocampus (18% at 7 days; 44% at 30 days; 58% at 60 days) of ADX rats was found, which was accompanied by a comparable decrease in the abundance of PDYN mRNA. An in situ hybridization analysis revealed that both the number of positively hybridized cells and the number of silver grains per cell were decreased in the dentate gyrus after ADX. The administration of dexamethasone after surgery reversed the peptide and mRNA attenuation induced by ADX. ADX had no effect on the expression of proenkephalin mRNA or [Met5]-enkephalin immunoreactivity in the hippocampus. Examination of thionin-counterstained tissue showed that the dentate granule cell layer was intact. The decrement of DYN expression in this system is proposed to have resulted from the removal of glucocorticoid input and not dentate granule cell loss. This study provides the strong evidence for a differential susceptibility of these two opioid peptides in the hippocampus to the removal of glucocorticoids. In addition, these data provide support for a potentially selective, glucocorticoid-permissive component in PDYN gene expression.

Adrenal Glands↗
PubMed1992

Case report--melanoma of the anorectum.

Melanomas of the gastrointestinal tract are rare tumours, the anorectum being the most common site. Anorectal melanomas can pose difficult diagnostic and therapeutic problems. Awareness on the part of both the clinician and histopathologist that melanomas can rarely occur in the anorectum is an important pre-requisite to its diagnosis as specific histopathological staining may be required. Therapeutically, surgery remains the primary option. Prognosis is however poor as metastatic disease is commonly established at presentation. When the tumour is sited in the rectum, the cells of origin is controversial. A case of disseminated anorectal melanoma is described.

Biomarkers, Tumor↗
PubMed1992

Clotest (rapid urease test) in the diagnosis of Helicobacter pylori infection.

Over a period of 3 months, 85 patients who underwent gastroscopy had antral biopsy taken for Clotest, histology and/or culture for Helicobacter pylori (HP). The sensitivity and specificity of Clotest were found to be 77% and 96% respectively with negative predictive value of 63% and positive predictive value of 98%. Ninety-two percent of the positive Clotests were positive within 20 minutes, thus giving rapid result. Therefore, Clotest is a rapid, sensitive and highly specific test for HP infection. A high correlation between HP infection and chronic gastritis was noted and the prevalence of HP infection in patients with duodenal ulcer (90%) was higher than that of gastric ulcer (64%) or non-ulcer group (65%).

Adolescent↗
PubMed1991

Effect of omeprazole on duodenal ulcer-associated antral gastritis and Helicobacter pylori.

This study set out to investigate the effects of omeprazole or ranitidine on the progression of antral gastritis and Helicobacter pylori in patients with active duodenal ulcer. A double-blind, double-dummy trial was performed in 270 patients, 241 of whom were studied histologically for the presence of H. pylori. Patients were randomized to receive omeprazole, 10 mg every morning, omeprazole, 20 mg every morning, or ranitidine, 150 mg twice a day, for four weeks. Endoscopy was performed on entry and at weekly intervals during the study; at least two antral biopsies were taken on each occasion to assess the activity and degree of chronic inflammation, as reflected by the degree of polymorphonuclear leukocyte infiltration and mononuclear cell infiltration, respectively. Biopsy specimens also were assessed histologically for H. pylori. The sex, age and maximal acid output were comparable in the three treatment groups. The percentages of patients showing an improvement in the activity of gastritis in the four consecutive weeks of treatment were 9%, 40%, 51%, and 53% for omeprazole, 10 mg (N = 78); 14%, 42%, 49%, and 53% for omeprazole, 20 mg (N = 81); and 2%, 23%, 30%, and 33% for ranitidine, 150 mg twice a day (N = 82) (life table analysis gave P less than 0.01 for both omeprazole regimens compared with ranitidine). The degree of chronic inflammation showed similar changes. The density of H. pylori decreased significantly after treatment with omeprazole, 10 mg or 20 mg, (both, P less than 0.00001) but not with ranitidine.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Pathogenetic role of Helicobacter pylori in duodenal ulcer disease. Multivariate analysis of factors affecting relapse.

The pathogenesis of duodenal ulcer disease is multifactorial and the contribution of Helicobacter pylori in relation to the other factors to the release of duodenal ulcer is unknown. To investigate this, we studied 147 patients with endoscopically proven healed ulcers. These patients were randomized to receive either placebo, misoprostol 200 micrograms or misoprostol 300 micrograms four times daily, and clinical, personal, physiological and endoscopic characteristics were obtained prospectively. Endoscopy was performed at the active phase of the ulcer and when the ulcer healed. Biopsies were taken from the antrum to assess histologically for: (1) the activity of gastritis as assessed by the degree of polymorph infiltration, (2) the degree of chronic inflammation by the degree of chronic inflammatory cells infiltration and degree of mucosal degeneration, and (3) bacteriologically for the presence of H. pylori. The severity of the gastritis and the bacterial density were graded independently by two pathologists. The patients were assessed at two-month intervals for 12 months or until the ulcer relapsed. The results demonstrated that the relapse rates of duodenal ulcer were similar in the three treatment groups. The relapse rate was higher in the group with higher density of the bacteria (P less than 0.05). The degree of gastritis did not affect the relapse rate of duodenal ulcer in either the placebo or misoprostol group or in all patients combined. Stepwise logistic regression analysis identified that increased duodenal inflammation, male sex, early-onset disease, and H. pylori adversely affected relapse of the ulcer. We conclude that multiple factors affect the relapse of duodenal ulcer and H. pylori is one of them.

Adult↗
PubMed1991

Retention between a serrated steel dowel and different core materials.

This in vitro study compared the retention of dowel posts using different core materials. Glass ionomer cements, composite resin, and amalgam core materials were combined with serrated dowel posts to form post and core assemblies. Individual post-core assemblies were mounted with a special jig in an Instron Universal testing machine. A tensile force was applied at a cross-head speed of 0.02 cm/min and the separation force was recorded. Glass ionomer cement core materials were weak in tension and metalized ionomers remained brittle and were not fracture resistant. Composite resin and amalgam were strong in tension and relatively fracture resistant.

Analysis of Variance↗
PubMed1990

Ultrastructure of preimplantation human embryos co-cultured with human ampullary cells.

Ova with two pronuclei were co-cultured with established human ampullary cell lines and various stages of preimplantation embryonic development were monitored by Nomarski optics and then assessed by transmission electron microscopy (TEM). Fifteen embryos ranging from the 2-cell stage to blastocyst hatching were examined for normal and abnormal features. Their ultrastructure was similar to that of embryos cultured in Whittingham's T6 medium, reported previously. Seven embryos were evidently morphologically normal and showed good organization of fine structure. Most cellular organelles underwent progressive changes during early development. There was evidence of enhanced embryonic genome activation at the 8-cell stage. Invariably, all embryos had few too many fragments, some internalized, which were later segregated into the blastocoele or found outside the trophoblast of the late morula and blastocysts. Six grossly 'normal' embryos assessed by Nomarski had multiple nuclei of various dimensions, which highlights the subjectivity of embryo assessment in the IVF laboratory. Incomplete incorporation of chromatin into nuclei and formation of micronuclei were evident in some blastomeres. The results are discussed in relation to early embryonic loss, prevalent in IVF. Significant events reported include the detection of centrioles at the 8-cell stage, cavitation of the early blastocyst and the initiation of blastocyst hatching visualized by TEM.

Blastocyst↗
PubMed1990

c-myc Oncogene expression in colorectal cancer: its use in prognosis and role in colorectal carcinogenesis.

Expression of the c-myc oncogene was studied in 35 cases of colorectal cancer. Elevated expression was found in 46% (16/35) of cases. This elevated c-myc expression was not significantly correlated with tumour stage, tumour size, tumour differentiation or carcinoembryonic antigen gene expression, demonstrating that it is not a useful prognostic indicator in colorectal cancer. The role of c-myc in colorectal carcinogenesis is discussed in the light of these findings and of the recent advances in molecular biology.

Biomarkers, Tumor↗