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S T Yuen

Publications and source records attributed to S T Yuen.

82 records · Page 5Linked to original sources
PubMed1994

Influence of chronic nicotine intake and acute ethanol challenge on gastric mucus level and blood flow in rabbits.

The effects of nicotine pretreatment on ethanol-induced gastric mucosal lesions and changes of gastric mucosal mucus levels and blood flow (GBF) were studied in anaesthetized rabbits. Nicotine treatment 25 or 50 micrograms/ml drinking water did not affect the volume of water consumption during the 10-day experimental period. It did not produce gastric mucosal lesions or affect the superficial adherent mucus content. The length of mucus-containing cells and the basal GBF were also unaffected. Intragastric administration of absolute ethanol reduced GBF, this effect was not altered by nicotine. However, the alkaloid potentiated the ulcerogenic actions of ethanol both on lesion formation and mucus depletion evoked by graded oral doses of ethanol (50 or 100%, v/v). Ultrastructurally, the mucous cells were more degenerated in the animals co-treated with nicotine and ethanol. It is concluded that reductions of mucus-containing cells and adherent mucus on the gastric mucosa are likely to be the contributory factors involved in the aggravating action of nicotine on ethanol-induced gastric mucosal lesions in rabbits.

Animals↗
PubMed1994

Ultrasound guided transperineal prostatic aspiration biopsy: experience in Hong Kong.

OBJECTIVE: The purpose of this study is to correlate the result of the ultrasound guided transperineal aspiration biopsy with the clinical findings. MATERIALS AND METHODS: We retrospectively studied 27 patients who had been subjected to ultrasound guided transperineal prostatic aspiration biopsy in our institution during the period 1990 to 1992. The patients were divided into two groups: Group A--those with clinically palpable nodules on digital examination, and Group B--those without palpable nodule but with clinical evidence of prostatic enlargement and/or bladder outlet obstruction. RESULTS: There were 8 biopsy proven cancers, 4 of them were palpable lesions while the other 4 were clinically non-palpable. The overall positive predictive value was 29.6%; this increased to 40% if the lesions were palpable but decreased to 23.5% if the lesions were non-palpable. CONCLUSION: The overall positive predictive value of this technique was found to be consistent with other studies using different methods of biopsies. The positive predictive value was increased if the abnormality was clinically palpable. This technique was also found to be safe and no significant complication was observed in these patients.

Aged↗
PubMed1993

Surgical lateral clearance in resected rectal carcinomas. A multivariate analysis of clinicopathologic features.

BACKGROUND: Incomplete removal of the tumor is the main cause of local recurrence in rectal carcinomas; this often occurs at the lateral aspects devoid of the peritoneum. The authors examined prospectively 80 resected rectal carcinoma specimens in an attempt to discover a reliable method to detect lateral resection margin (LRM) involvement by these tumors and to identify pathologic factors that would be prognostically important. METHODS: In each of the 80 resected specimens, the whole tumor was embedded, and whole-mount sections of the entire tumor and the surrounding mesorectum were examined after serial transverse slicing. The distance from the outermost part of the tumor to the LRM (surgical clearance) was measured. RESULTS: Six (7.5%) of the 80 specimens showed LRM involvement (defined as surgical clearance < or = 1 mm) in the single slice seen macroscopically to have the deepest tumor invasion, whereas 16 specimens (20%) were found to have LRM involved after examining all slices microscopically. Surgically clearance had a strong inverse relationship with Dukes staging (P < 0.001) and depth of tumor invasion (P = 0.001). The overall local recurrence rate was 28%; it was much higher (53%) in the patients who had LRM involved by tumor. As a whole, local recurrence was related significantly to LRM involvement (P = 0.006). Survival rates were correlated with macroscopic (n = 3) and microscopic (n = 13) features of the resected specimens using Cox multivariate regression analysis. Three of the nine pathologic parameters isolated (i.e., surgical clearance, cellular differentiation, and number of involved pericolic lymph nodes) were identified as favorable independent prognostic factors. CONCLUSIONS: Local recurrence is related closely to LRM involvement. Embedding and examining the entire tumor and mesorectum is the only reliable and satisfactory means of assessing LRM. Detailed pathologic study on the resected tumor is important when assessing the prognosis.

Adenocarcinoma↗
PubMed1993

Pattern of cerebral atherosclerosis in Hong Kong Chinese. Severity in intracranial and extracranial vessels.

BACKGROUND AND PURPOSE: The clinical pattern of stroke and the angiographic distribution of cerebral atherosclerosis in Chinese are different from those in Caucasians. Pathological data from autopsy studies are lacking. METHODS: The intracranial and extracranial arteries supplying the brains of 114 consecutive Chinese patients undergoing autopsy in a regional general hospital were examined by computer-assisted morphometric analysis under a microscope as well as by macroscopic grading for atherosclerotic narrowing. The severity was correlated with various atherosclerosis-related factors. RESULTS: Atherosclerosis of the intracranial cerebral vessels was more severe than that of the extracranial vessels. The distal branches of the intracranial vessels were also commonly involved. Hypertension and diabetes mellitus were identified as factors associated only with intracranial atherosclerosis (p < 0.001), whereas ischemic heart disease was associated with atherosclerosis in both the intracranial (p < 0.001) and extracranial (p = 0.012) vessels. Smoking was associated with narrowing of the extracranial vessels only (p = 0.0054). CONCLUSIONS: Compared with figures from Caucasian and Japanese populations, the extent of intracranial atherosclerosis is much more severe in Hong Kong Chinese, whereas atherosclerotic narrowing of the extracranial carotid artery is less severe in Hong Kong Chinese than in Caucasians.

Adolescent↗
PubMed1992

Central neurocytoma: its differentiation from intraventricular oligodendroglioma.

Two patients with intraventricular tumours are presented. Both had similar features on light microscopic examination. On the basis of the specific immunohistochemical staining patterns and the ultrastructural findings, one was diagnosed as a central neurocytoma while the other was diagnosed as an intraventricular oligodendroglioma. The possibility of central neurocytoma should be considered in all young patients including children presenting with an intraventricular lesion. Definitive diagnosis requires electron microscopic and immunohistochemical studies.

Adult↗
PubMed1992

Sudden death from secondary massive pulmonary embolism derived from marrow emboli trapped by Chiari's network.

We report a case of fatal massive pulmonary embolism in an 86-year-old woman. The embolus occurred as a result of embolic bone marrow particles from a fractured femur becoming trapped by a Chiari's network which then acted as a source for propagation of a large thrombus which detached and caused sudden death from massive pulmonary embolism. To our knowledge this is the first report of such a case.

Aged↗
PubMed1991

An autopsy study of pulmonary thromboembolism in Hong Kong Chinese.

A retrospective study of autopsied material in the last 15 yrs is documented an increasing incidence of pulmonary thromboembolism (PTE) in Hong Kong Chinese. The incidence of significant PTE increased from 0.58% in the first 5 yr period to 2.08% in recent years. The topographic features and characteristics of these PTE patients are analysed and the factors contributing to the changes are discussed.

Adolescent↗
PubMedDate not supplied

Carcinoma of the colon with synchronous hepatic metastasis in a cirrhotic liver harboring a hepatocellular carcinoma.

Tumor metastasis to a cirrhotic liver is rare. It has been suggested that colorectal cancer does not metastasize to the cirrhotic liver. We reported a 65 year-old man, a known carrier of hepatitis B surface antigen, diagnosed to have hepatocellular carcinoma with routine screening. A partial hepatectomy with resection of segments VI and VII was performed. The hepatectomy specimen revealed a 4.5 cm diameter HCC in a cirrhotic liver. Incidentally, 0.8 cm diameter ulcer at the descending colon. Histological examination of the left hemicolectomy specimen showed a moderately differentiated adenocarcinoma.

Adenocarcinoma↗
PubMedDate not supplied

Hemoperitoneum caused by spontaneous rupture of a true splenic cyst.

A 34 year-old man presented with hemoperitoneum from a spontaneously ruptured spleen. At laparotomy, a 5-cm diameter splenic cyst was found to be ruptured. Histological examination confirmed the diagnosis of a true splenic cyst of the mesothelial type. Spontaneous rupture with hemoperitoneum is a rare but potentially lethal complication of a true splenic cyst.

Adult↗