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Biomedical subjects

J L Larsen

Publications and source records attributed to J L Larsen.

At least 127 records · Page 7Linked to original sources
PubMed1989

Giant cell glioblastoma: a work-up of 2 cases with long survival.

Two patients, in whom visual disturbance (Case 1) and sudden hemiparalysis due to a hemorrhagic lesion (Case 2) had led to craniotomy and histological diagnosis of giant cell glioblastoma, each had an unexpectedly long survival period of 7 and 9 years, respectively. Radiologically, the tumours were well demarcated, but without any distinguishing features, by comparison with glioblastomas in general. The tumours, to a great extent, consisted of cells with large, bizarre multiple nuclei. The highly pleomorphic cells displayed strong cytoplasmic GFAP immunopositivity, which suggested an astroglial origin. Thus, these tumours were considered a variant of glioblastoma ("giant cell glioblastoma") with a more favourable prognosis than experienced by most patients with glioblastoma.

Adult↗
PubMed1989

Electroconvulsive therapy and cerebral computed tomography. A prospective study.

Cerebral computed tomography (CT) was performed before and after right-sided electroconvulsive therapy (ECT) in 40 patients aged 26-87 years with major affective disorders. Nine patients with a concomitant definite or possible non-acute organic brain disorder were included. Several patients had long seizure durations, maximum 6.5 min, caused by hyperventilation-induced hypocapnia. Twenty-nine patients received at least 16 treatments (maximum 46). No CT changes occurred following ECT. A questionable dilatation of the left temporal horn in a 69-year-old hypertensive man who recovered completely without side effects after 3 ECT sessions was probably unrelated to the ECT. Provided sufficient oxygenation, even relatively long ECT series and seizures lasting several minutes do not cause any brain damage visible on CT.

Adult↗
PubMed1989

Glioblastoma associated with multiple sclerosis: coincidence or induction?

A 63-year-old man died of a brain tumor 29 years after onset of multiple sclerosis (MS). The MS diagnosis was based upon clinical evidence of two brain stem lesions, separate in time, retinal periphlebitis, a fluctuating course of the disease, and supported by the observation of definite cognitive impairment at the age of 41 years, and an increased number of lymphocytes in the cerebrospinal fluid which normalized during gradual recovery. The MS diagnosis was confirmed at autopsy, which also revealed a glioblastoma developing adjacent to typical MS plaques.

Brain↗
PubMed1988

Study of Vibrio anguillarum strains from different sources with emphasis on ecological and pathobiological properties.

A total of 317 Vibrio anguillarum strains were isolated from water, sediment, and diseased as well as healthy rainbow trout at a Danish mariculture farm and from feral fish caught close to the farm. All strains were examined serologically. Ten sera permitted determination of the O group in 66.7% of the strains from diseased rainbow trout. Furthermore, the O group could be determined in 45.1 to 65.4% of the strains from mucus, gills, and intestinal contents of healthy rainbow trout, while only 22.2 to 28.8% of the isolates from water, sediment, and gills or mucus of feral fish were groupable. Serogroup O1 and to some extent O2 appeared to be associated with trout. Strains from these serogroups were selected for analyses of hemagglutinating activity and surface hydrophobicity. Serogroup O1 comprised hemagglutinating as well as nonhemagglutinating strains; from cases of vibriosis, all O1 strains were nonhemagglutinating. The strains belonging to serogroup O2 were generally hemagglutinating. Examinations of surface hydrophobicity by salt aggregation and hydrophobic interaction chromatography suggested that the O1 strains were more hydrophobic than the O2 strains. In pathogenicity tests, O1 strains isolated from gills and mucus of healthy rainbow trout killed all trout in the test groups. A strain from the intestinal contents of healthy rainbow trout did not produce significant mortality. This strain could, however, be frequently reisolated from the pronephros of fish in the test group concerned. After challenge with strains from eel mucus and seawater, mortality was not produced, and furthermore, these strains could not be reisolated from the pronephros.

Animals↗
PubMed1988

Modulation of prolactin-stimulated Nb2 lymphoma cell mitogenesis by cholera toxin and pertussis toxin.

We have investigated whether cholera toxin (CT)- or pertussis toxin (IAP)-sensitive G proteins are involved in ovine (o) PRL-stimulated mitogenesis in the lactogen-dependent rat Nb2 node lymphoma cell line. Addition of IAP to medium caused a biphasic effect on oPRL-stimulated cell number. Low doses (10(-3) ng/ml) enhanced (mean +/- SEM, 15 +/- 3%) whereas higher doses (greater than or equal to 10 ng/ml) inhibited (24 +/- 3%) mitogenesis stimulated by a submaximal dose of oPRL (0.1 ng/ml) compared to control values. The cAMP analog 8-bromo-cAMP also had a biphasic effect on cell division stimulated by submaximal doses of PRL. Low doses (10(-5) M) enhanced whereas higher doses (10(-3) M) inhibited Nb2 cell growth in response to PRL. Incubation with CT only inhibited oPRL-stimulated mitogenesis in a dose-dependent manner. Maximal inhibition (63 +/- 7%) occurred at a concentration of 10 ng/ml or more. Phorbol myristate acetate (PMA) enhanced mitogenesis stimulated by PRL alone and in the presence of either stimulatory or inhibitory doses of IAP, but PMA did not block IAP inhibition. In contrast, PMA had no effect on cells incubated with CT; the inhibition of PRL-stimulated cell division by CT remained unchanged. Lactogenic receptor-binding sites per cell and affinity were not significantly affected by PMA, IAP, or CT, suggesting a postreceptor mechanism of action. In summary, these data demonstrate that cAMP modifies PRL-stimulated Nb2 cell mitogenesis. The differences between IAP and CT (i.e. biphasic effect, degree of inhibition, and differential effect of PMA) suggest that these agents could also modulate PRL actions in the Nb2 cell through different mechanisms, including a cAMP-independent pathway.

8-Bromo Cyclic Adenosine Monophosphate↗
PubMed1988

Effect of subinhibitory concentrations of tiamulin on the haemagglutinating properties of fimbriated Escherichia coli (K88, K99).

The haemagglutinating properties (HA) of Escherichia coli possessing the fimbrial antigens K88 and K99 were significantly affected by tiamulin. HA for K88-positive strains was reduced at 1/10 to 1/40 minimum inhibitory concentration (MIC), while the corresponding values for the K99 strains were 1/2 to 1/10 MIC. Tiamulin concentrations of 3 to 12 micrograms ml-1 increased salt aggregation test values from between 1.4 and 1.5, to more than 2.

Animals↗
PubMed1987

Toxins, putative cell adhesins and fibronectin binding properties of Salmonella dublin.

Fifty Salmonella dublin strains isolated from cattle and human diarrhoeal cases were assayed for toxin production, haemagglutination, cell-surface hydrophobicity and fibronectin-binding properties. Most strains (65% of tested) produced cytotonic toxins and cytotoxic factors when tested on Chinese hamster ovary (CHO) cells and rabbit skin test. However, only three strains produced a skin-permeability factor as determined in pig skin intra-dermal tests. None of the strains were positive in pig intestinal loop tests. Six of the 32 strains tested for 125I-fibronectin and its 125I-29 kDa N-terminal domain binding showed 10-17% and 6-10% binding, respectively. Most of the strains expressed mannose-sensitive haemagglutination (MSHA) (76%) and high cell-surface hydrophobicity (74%) when grown at 37 degrees C. At 20 degrees C the expression of MSHA and especially the expression of high cell-surface hydrophobicity were reduced. Twelve strains grown at 37 degrees C did not haemagglutinate erythrocytes from five animal species used in this study, while six of these strains expressed high cell-surface hydrophobicity. Salmonella dublin strains isolated in Denmark appeared to express a higher frequency of fimbriae type 1 (MSHA) and a lower frequency of high cell-surface hydrophobicity than the strains from external sources.

Animals↗
PubMed1987

Prolactin alters luteinizing hormone pulsation characteristics in the intact and castrate male rabbit.

The effect of prolactin (PRL) on luteinizing hormone (LH) pulsation characteristics in intact and castrate male rabbits was investigated. Eight groups of animals were studied. Two groups castrate and two groups of adult male rabbits served as controls to establish baseline pulsation characteristics. Preliminary studies showed that a sampling interval of 3-4 min was optimal. One group of castrate and one group of intact rabbits were sampled at this frequency for 60 min; two additional groups were sampled for 240 min. With these data determined, four groups were used in paired studies: two castrate and two intact groups received either a bolus injection intravenously of saline or PRL (20 micrograms), followed by a constant infusion of saline or PRL (50 micrograms/min) for 3.5 h. Blood was sampled every 3 min for the last 1.5 h of infusion. Serum LH was measured on each sample; rabbit PRL was measured on pooled samples. In selected samples bovine PRL was also measured. The LH pulsation characteristics of the 3 groups of castrate and intact controls (unperfused and saline-perfused) were not statistically different and the data were pooled. The PRL-treated animals were compared to the controls. Castration increased LH mean concentration, pulse amplitude and duration. PRL infusion decreased mean LH concentration and pulse amplitude in both intact and castrate animals. Pulse duration was decreased significantly in castrate, but not in intact, animals by PRL infusion. We conclude that, in the adult male rabbit, PRL modulates LH pulsation. This action of PRL must occur either directly at the pituitary or more probably through an influence on gonadotropin-releasing hormone pulsation at the hypothalamus.

Animals↗
PubMed1986

Primary adrenocortical nodular dysplasia, a distinct subtype of Cushing's syndrome. Case report and review of the literature.

Non-iatrogenic Cushing's syndrome has been associated primarily with three entities: pituitary-dependent processes due to pituitary adenomas or microadenomas causing adrenal hyperplasia; pituitary-independent primary adrenal causes, predominantly unilateral adenomas, rarely multiple adenomas or adrenal carcinoma; ectopic sources of adrenocorticotropic hormone (ACTH) production. Although non-neoplastic bilateral adrenal disease generally has been ascribed to extra-adrenal stimulation, a rare cause of Cushing's syndrome that involves bilateral adrenal nodule formation independent of pituitary stimulation has been identified. Nodular adrenal diseases represent a confusion of terms in the literature, but one subgroup of Cushing's syndrome has most frequently--and, perhaps, most appropriately--been designated primary adrenocortical nodular dysplasia. A case of this unusual entity is presented, and previous case reports pertaining to this confusing area of adrenal hyperfunction are reviewed. The characteristic manifestations that separate this diagnosis from other types of nodular adrenal disease are also discussed. Recognition of this diagnosis, although rare, is important, as bilateral adrenalectomy in the treatment of choice.

Adolescent↗
PubMed1986

Serotyping of Vibrio anguillarum.

A serotyping scheme based on the detection of O antigens by slide agglutination in fish-pathogenic strains of Vibrio anguillarum is presented. Over a period of 5 years 270 Vibrio strains from feral and cultured fish, 189 strains from the environment, and 36 strains from invertebrates were collected. The strains were divided into 10 distinct serotypes (O1 through O10). More than 90% of the fish-pathogenic strains, but only 40% of the environmental strains, were typable; 71% of the strains isolated from cultured rainbow trout were serotype O1, whereas 78% of the strains isolated from feral fish were serotype O2. No dominating environmental serotype was found. A serotyping system for V. anguillarum is proposed. A total of 90 strains received from culture collections and laboratories in different countries were typed according to the present system.

Animals↗