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Biomedical subjects

S K Lim

Publications and source records attributed to S K Lim.

At least 109 records · Page 6Linked to original sources
PubMed1986

Preliminary observations on the influence of antibiotics on the ecology of Escherichia coli and the enterococci in the faecal flora of healthy young chickens.

Two separate replicated experiments are described. In the first the influence of oxytetracycline on the Escherichia coli flora was assessed, while in the second the effect of tylosin on the enterococci was investigated. In both experiments the administration of the antibiotic was associated with an increase in the average proportion of isolates resistant to the agent although in experiment 1 the agent had no apparent influence on either the total number of E. coli strains, differentiated by biotype and resistance pattern, or the number of 'new' strains per sampling. On the other hand significant differences were noted between the two replicates and also in relation to the age of the birds. In the second experiment fewer enterococcal strains were isolated from the birds dosed with tylosin but since fewer strains on average were isolated from the samples collected prior to dosing it is probable that this difference was due to factors other than the influence of the antibiotic. The enterococci were speciated and the two most commonly isolated were Streptococcus faecalis and S. faecium. The isolation rate of each was expressed as a proportion of the total number of enterococcal isolates per sample and when considered in relation to both dosing and the age of the bird the interaction dosing X age was statistically significant for both species. However, the differences did not appear particularly great and it was possible that the differences were of no practical importance from an ecological point of view.

Animals↗
PubMed1983

Virilizing lipid cell tumor of the ovary: light and electron microscopic studies.

Lipid cell tumor of the ovary is among the rarest tumors belonging to the virilizing group of ovarian neoplasms. A lipid cell tumor of the ovary is described in an 18-year-old woman with secondary amenorrhea, hirsutism, and frank virilization. Current diagnostic features, preoperative and postoperative androgen determinations, and histomorphological and ultrastructural studies are presented. Prompt diagnosis and treatment are emphasized in this potentially malignant and disfiguring androgenic tumor that is readily amenable to surgery.

Adenoma↗
PubMed1982

On the preferred rotameric conformation for dopamine agonist action: an illusory quest.

Putative dopamine agonists from the 2-aminotetrahydronaphthalene and trans-octahydrobenzo (f) and (g) quinoline series were shown to inhibit the spontaneous locomotor activity of mice. Marked potency differences were observed between the alpha-and beta-rotameric conformations, compounds having the alpha-rotameric conformation having the greater potency. Thus, 2-di-n-propylmino-5,6-dihydroxytetrahydronaphthalene was 339 times more potent than the 6, 7-dihydroxy isomer, and 2-n-propylamino-5,6-dihydroxy-compound was respectively 79 times and 179 times more than 6,7-hydroxy-and 7,8-dihydroxycompounds. trans-7,8-dihydroxy-1-n-propyl-1,2,3,4,a,9,10,10b-octahydrobenzo(f)quinoline was 11 times more potent than the beta-rotamer, the 6,7-dihydroxy compound, and within the trans-octahydrobenzo(g)quinoline series the alpha-rotameric N-propyl derivative was 467 times more potent than the beta-rotamer, and the alpha-rotameric greater than N-H analogue was 46 fold more potent than the beta-rotamer. Thus, the alpha-rotamer appears the more potent in causing the present functional dopaminergic change. The dopaminergic nature of the response was indicated by its sensitivity to spiroperidol but not to yohimbine or prazosin. The possibility that a difference in behavioural potency between the alpha- and beta-rotamers may reflect a differential metabolism by catechol-O-methyl transferase was assessed by administration of different agonists after pyrogallol pretreatment. This potentiated the activity of 2-di-n-propylamino-6,7-dihydroxytetrahydro-naphthalene but not that of the 5,6-dihydroxy analogue. However, changes in the effects of N-propyl derivatives of trans-octahydrobenzo (f) and (g)quinoline were not marked and, in all experiments, pyrogallol treatment failed by orders of magnitude to shift the dose-response curves of the beta-rotamers to indicate a comparable potency to the rotameric forms.

Animals↗
PubMed1981

Characterisation of the mechanisms by which purported dopamine agonists reduce spontaneous locomotor activity of mice.

The spontaneous locomotor activity of mice, recorded in the first 20 min period after placement in individual cages fitted with photocells, was reduced dose-dependently by apomorphine, (-)-N-n-propylnorapomorphine, 2-dimethylamino-5,6-dihydroxytetralin (M-7), 2-di-n-propylamino-5,6-dihydroxytetralin, (3,4-dihydroxyphenylamino)-2-imidazoline (DPI), N-n-propyl-benzo(f) and (g) quinolines, bromocriptine, N-n-propyl-3-(3-hydroxyphenyl)-piperidine (3-PPP) and by the N,N-dimethyl-, -diethyl-, -dipropyl- and -dibutyl-dopamines. SK&F 38393, in a wide dose range, failed to modify spontaneous locomotion. The inhibition of spontaneous locomotion caused by 2-di-n-propylamino-5,6-dihydroxytetralin was reversed by spiroperidol, haloperidol, benperidol and (-)-sulpiride, used in doses which did not in themselves modify spontaneous locomotion, but not by similarly selected doses of trifluperidol, fluphenazine, oxiperomide, molindone, thioridazine, prazosin, picrotoxin, methysergide, yohimbine, propranolol, phentolamine, atropine or SK&F 38393. Spiroperidol was also shown to reduce the actions of N,N-diethyl-, N,N-dipropyl- and N,N-dibutyl-dopamine, M-7, bromocriptine, apomorphine and, less markedly, 3-PPP and the (f) and (g)benzoquinolines, but not the actions of N,N-dimethyldopamine or DPI. Yohimbine reversed the action of DPI but ont that of any other purported dopamine agonist, whilst prazosin was ineffective throughout the experiments. The neuroleptic agents did not in themselves cause significant increase in spontaneous locomotor activity. Data is discussed in terms of a dopamine-neuroleptic sensitive mechanism for motor inhibition.

Animals↗
PubMed1981

Simultaneous primary carcinomas--a report of three cases.

Two separate primary carcinomas occurring simultaneously in the esophagus and stomach are uncommon. The authors report three cases of this entity, squamous cell carcinoma of the osophagus and adenocarcinoma of the stomach, one of which is classified as a collision carcinoma of the stomach. Because of the rarity of collision tumors of this histologic variety, the world literature was reviewed. Diagnostic features and the relative prognosis of dual primary carcinomas are discussed.

Adenocarcinoma↗
PubMed1979

Adenoid cystic carcinoma of breast with metastasis: a case report and review of the literature.

Adenoid cystic carcinoma of the breast is a rare tumor having a favorable prognosis. At this writing, less than 100 cases have been reported. A review of the literature discloses only six well-documented cases with associated distant metastases. The characteristic biological behavior of this tumor appears to be the development of distant metastasis without prior detectable invasion of axillary lymph nodes.

Breast Neoplasms↗
PubMed1974

Direct fluorescent-antibody method for the diagnosis of Pneumocystis carinii pneumonitis from sputa or tracheal aspirates from humans.

A direct fluorescent antibody (DFA) method was applied to sputum or tracheal aspirate from 68 patients with clinical or radiological evidence suggesting Pneumocystis carinii pneumonitis, and to 50 control patients. P. carinii was detected by DFA in specimens from 33 of the 69 clinical cases and 3 of the 50 controls. Specimens of lung from 11 of 33 DFA-positive cases were examined histologically, and 9 were positive. Four of 35 DFA-negative cases were examined histologically, and all were negative. Sputa or tracheal aspirates from 6 patients who were positive by both DFA and histological examination were examined also by methenamine silver staining; none could be diagnosed conclusively by this method. The results indicate that the DFA method is a sensitive and dependable procedure for the laboratory diagnosis of P. carinii pneumonitis in man.

Acetylcysteine↗
PubMed1973

Development and evaluation of a direct fluorescent antibody method for the diagnosis of Pneumocystis carinii infections in experimental animals.

Because no fully satisfactory diagnostic method has been available for use in pneumocystis infection, an attempt was made to apply the fluorescent antibody technique in the identification of Pneumocystis carinii. Hyperimmune sera were prepared in rabbits against P. carinii from human and rat sources. After proper adsorption, these antisera were conjugated with fluorescein isothiocyanate and used as reagents in a direct fluorescent antibody procedure. Each of the two reagents was found to stain trypsin-treated P. carinii organisms from either human or rat sources, indicating the presence of common antigens. Stained organisms were demonstrated in the hypopharyngeal material from rats in which pneumocystis infection had been activated by the administration of corticosteroid. From the results reported here, the procedure outlined is considered sufficiently sensitive and specific to justify tests on pneumocystis infections in man. The findings in a series of specimens from human subjects will be reported separately. The method also provides an extended approach to related research problems. The need for controls of the procedure at all points is emphasized.

Animals↗