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Biomedical subjects

W C Lin

Publications and source records attributed to W C Lin.

At least 145 records · Page 8Linked to original sources

[Adenomatous polyps of the prostatic urethra. A report of four cases].

A benign prostatic urethral polyp is considered as an unusual lesion of the urethra. It attracts the patient or doctor's attention only when hematuria or hemospermia is noted. From August 1987 to June 1988, the authors found four cases of posterior urethral polyps in the Taitung Branch of Mackay Memorial Hospital. Hematuria was found in all of the 4 patients and hemospermia was found in one. Three patients presented gross hematuria, and one microscopic hematuria. Of the four, two had suprapubic soreness; one had perineal discomfort; and only one manifested no symptoms at all. All of the patients underwent a cystoscopic biopsy, and their specimens were stained and studied by the immunoperoxidase method. All of the specimens were PSA positive, and presented a picture of adenomatous polyp. Only one patient received transurethral electrocoagulation because of continued hematuria and perineal discomfort that persisted even after a two week medical course that appeared to be more effective to the previous one. In conclusion, the authors believe that more of such lesions will be discovered when more attention is paid to the posterior urethra; when adenomatous polyps are suspected in patients who have the above symptoms; and when polyps are considered as a possibility in the differential diagnosis.

Adult↗

Possible involvement of the central GABAergic system in pentobarbital-stimulated gastric acid secretion in the perfused rat stomach preparation.

The effects of several convulsants and diazepam on pentobarbital-stimulated gastric acid secretion were studied in the perfused stomach of rats under urethane anesthesia. Picrotoxin and pentylenetetrazol, GABA antagonists, and 3-mercaptopropionic acid, an inhibitor of GABA biosynthesis, strongly inhibited the pentobarbital-stimulated gastric acid secretion. The secretory action of pentobarbital was transiently depressed by strychnine, a glycine antagonist, and by bicuculline, a GABA antagonist; vigorous convulsions were observed in these rats. Diazepam had no effect on the pentobarbital-stimulated gastric acid secretion. These findings suggest that the potentiation of central GABAergic mediation by pentobarbital could be a main mechanism involved in pentobarbital-stimulated gastric acid secretion.

3-Mercaptopropionic Acid↗

Effect of pentobarbital on gastric acid secretion elicited by secretagogues or electrical vagal stimulation in rats under urethane anesthesia.

The effect of pentobarbital, which stimulates gastric acid secretion in urethane-anesthetized rats, on secretagogue-stimulated or electrically stimulated acid secretion was studied in the rat perfused stomach. 2-Deoxy-D-glucose (2-DG)-stimulated gastric acid secretion was markedly depressed by intravenous injection of pentobarbital, but was definitely increased by lateral cerebroventricular injection and was unaffected by injection into the fourth cerebroventricle. Bethanechol-stimulated secretion was augmented by intravenous injection of pentobarbital. In vagotomized rats, pentobarbital did not affect the bethanechol-stimulated or electrically vagally stimulated secretion. These findings indicate that pentobarbital produces both stimulatory and inhibitory effects on gastric acid secretion through a central mechanism, especially in the forebrain. It was proposed that the inhibitory response would result from some interaction of intravenous 2-DG and pentobarbital in the central regulatory system of gastric secretion.

Animals↗

Stimulation of gastric acid secretion by microinjection of pentobarbital into the ventromedial hypothalamus.

Sites of stimulatory action of pentobarbital on gastric acid secretion were studied in rats anesthetized with urethane. Intracerebroventricular injection of pentobarbital dose-dependently stimulated gastric secretion. When injections of pentobarbital into the ventromedial hypothalamus were repeated with an interval of 30 min, the second and third consecutive injections produced a small but significant increase in gastric acid secretion. We propose that the ventromedial hypothalamus is involved in the stimulatory effect of pentobarbital on gastric acid secretion.

Animals↗

Stimulatory effect of pentobarbital and some anesthetics on gastric secretion in the continuously perfused stomach in rats under urethane anesthesia.

Effects of some anesthetics (pentobarbital, thiopental, alpha-chloralose and urethane) on gastric acid secretion were studied in the continuously perfused stomach in rats. Under urethane anesthesia, pentobarbital, thiopental and alpha-chloralose showed a definite stimulation on gastric acid secretion. Pretreatment with atropine or hexamethonium abolished the pentobarbital-induced acid secretion. Pentobarbital and thiopental did not elicit acid secretion in bilateral truncal vagotomized rats. In spinal rats, pentobarbital also stimulated acid secretion, but urethane, which was subcutaneously administered, reduced spontaneous acid output. The present results indicated that some anesthetics could stimulate gastric secretion in the anesthetized rat in contrast to the previously described inhibitory effect in the Shay rat.

Anesthesia↗

The pharmacological studies in central nervous system on the interaction of Taiwanese Veratri Formosani Rhizoma and Sophorae Radix.

The eighteen opposing drugs were to be recognized as absolute incompatibility of Chinese herbs. Ku-Shen (Sophorae Radix) opposed Li-Lu (Veratri Rhizoma) is one of these incompatible drugs. In this study, we attempted to investigate and identify the interactions of these two drugs in the CNS by means of modern pharmacological technics. The results elucidate that toxicity, number of retching movements, change of locomotor activity and the concentration of monoamines' metabolites of Li-Lu can be changed by Ku-Shen. From these results, further evidence was provided that the involvement of Li-Lu and Ku-Shen in the eighteen opposing drugs of Chinese ancient Pentsao are deemed to be significant.

Animals↗

Effects of ibuprofen on arylamine N-acetyltransferase activity in human colon tumor cells.

The inhibition of arylamine N-acetyltransferase (NAT) activity by ibuprofen was determined in a human colon tumour (adenocarcinoma) cell line. Two assay systems were employed, one with cellular cytosols (9000 g supernatant) and the other with intact colon tumour cell suspensions. The NAT activity in a human colon tumour cell line was inhibited by ibuprofen in a dose-dependent manner in both systems, i.e. the greater the concentration of ibuprofen in the reaction, the greater the inhibition of NAT activities in both systems. The data also indicated that ibuprofen decreases the apparent Km and Vmax of NAT enzyme from human colon tumour cells in both systems examined. This report is the first demonstration to show that ibuprofen affects human colon tumour cell NAT activity.

2-Acetylaminofluorene↗

Automated surface interpolation technique for 3-D object reconstruction from serial cross sections.

A method for automatically reconstructing a three-dimensional object from serial cross-sections is presented in this paper. The method combines the techniques of dynamic elastic contour interpolation, spline theory, and quadratic-variation-based surface interpolation. In the proposed method, the initial description of the object is formed by applying the elastic interpolation algorithm to generate a series of intermediate contours between each pair of consecutive cross-sections. After this, a preliminary processing for surface computation is carried out by mapping the contours into the domain of surface function and then using spline functions to calculate the initial surface values. Based on the output from the preliminary processing, we apply the quadratic-variation-based surface interpolation algorithm to calculate the final surface representation. Since our method takes the continuity of high order derivatives into consideration, the smooth and complete surface of a 3-D object can thus be reconstructed.

Arteries↗

Inhibition of N-acetyltransferase activity and DNA-2-aminofluorene adducts by glycyrrhizic acid in human colon tumour cells.

Glycyrrhizic acid (GA) was tested for inhibition of arylamine N-acetyltransferase (NAT) activity in a human colon tumour (adenocarcinoma) cell line (colo 205). Two assay systems were performed, one with cellular cytosols (9000g supernatant), the other with intact colon tumour cell cultures. The NAT activity in a human colon tumour cell line was inhibited by GA in a dose-dependent manner in both types of systems examined. The data also indicated that GA decreased the apparent values of K(m) and V(max) of NAT enzymes from human colon tumour cells in both examined systems. The DNA-2-aminofluorene adduct formation in human colon tumour cells were inhibited by GA. This report is the first to demonstrate that GA does inhibit human colon tumour cell NAT activity and DNA adduct formation.

4-Aminobenzoic Acid↗

Idiopathic thrombocytopenic purpura preceding malignant lymphoma: report of one case.

Idiopathic thrombocytopenic purpura (ITP) preceding malignant lymphoma is a rare condition. Most cases occur simultaneously with lymphoma or after it has been diagnosed. The case of a child with idiopathic thrombocytopenic purpura recovered after prednisolone treatment, but lymphoma developed four months later. The pathogenesis for idiopathic thrombocytopenic purpura evolving into malignant lymphoma is still unknown and further study is necessary.

Child↗