First Report of Impatiens necrotic spot virus in Ornamental Plants in Hungary.

Economically important viruses such as Tomato spotted wilt virus, genus Tospovirus, are transmissible mechanically and mainly by two thrips species (Thrips tabaci and Frankliniella occidentalis) in Hungary (1). Samples (31) of eight ornamental plant species (Catharanthus roseus, Cyclamen persicum, Dendranthema × grandiflorum, Eustoma grandiflorum, Gerbera sp., Impatiens walleriana, Ocimum basilicum, and Verbena hybrida) were studied. Symptoms including color breaking on flowers and necrotic symptoms on leaves were observed on four samples (C. persicum, I. walleriana, O. basilicum, and E. grandiflorum). Infection by Impatiens necrotic spot virus (INSV) was determined by double-antibody sandwich-ELISA and triple-antibody sandwich-ELISA using antisera obtained from Loewe (Sauerlach, Germany) and the DSMZ. Back inoculation with the F. occidentalis vector was also carried out to Lycopersicon esculentum as indicator plants. Back inoculation was also positive for INSV by symptoms and ELISA. The high amount of ornamental plant production together with the use of virus-infected propagation material and the increasing thrips vector populations may result in significantly increased establishment and distribution of INSV in Hungary. References: (1) M. L. Daughtrey et al. Plant Dis. 81:1220, 1997.

[Merkel cell tumor]. / Merkel-sejtes daganat.

Merkel cell cancer is a rare carcinoma arising from the neuroendocrin cells of the skin. The diagnosis is based on the clinical behaviour, histopathologic and ultrastructural findings and immunohistochemical results. An unusual case of Merkel cell carcinoma is presented. Mass from the umbiculus and a right inguinal lymph node was excised in a 63-year-old female. The histologic features of a typical, primitive small cell tumor combined with the immunohistochemical evaluations established the diagnosis. Rare polynuclear giant cells were focally present in our case. Patient was treated with combination of chemotherapy (Cisplatin, Etoposid) and radiotherapy. Control examinations showed complete respond. One year later metastasis developed. Resection of all known metastasis were performed. Two months after the laparotomy she died of metastatic disease. The autopsy did not reveal any other primary tumor. The capricious nature of the clinical course and the differences between this tumor and other carcinomas is emphasized.

Action of androgenic steroids on brain neurotransmitters in rats.

The effects of androgenic steroids on the dopamine (DA), noradrenaline (NA) and 5-hydroxytryptamine (5-HT) contents of different brain regions have been studied in order to elucidate the possible involvement of neurotransmitters in the negative feedback action of androgens. Administration of testosterone propionate (TP); (100 micrograms/kg or 5 mg/kg, i.p.) increased plasma testosterones, which reached a maximum at about 30 min following injections. TP (100 micrograms/kg) decreased the DA level in the hypothalamus to a minimum after 30 min and returned to normal level after 120 min. There was no effect in the amygdala, striatum and mesencephalon. Subsequent to 5 mg/kg i.p. TP administration, the minimum in the DA level was observed between 90 and 120 min in the hypothalamus, and after 120 min in the amygdala, but the treatment was without effect in the striatum and mesencephalon. Both doses of TP were ineffective as regards for in altering NA and 5-HT levels in the brain areas studied. In a dose of 5 mg/kg, androgens of different activities, such as norandrostenolone, dihydrostestosterone and androstenedione, decreased the DA contents of the hypothalamus and amygdala regions, but pregnenolone was ineffective. None of the androgens affected the NA and 5-HT levels in the brain areas studied. The data suggest that some of the actions of androgens are mediated via a dopaminergic mechanism in which not only the hypothalamus but also the amygdala is involved.

Study of the effects of neurotransmitters on the hypothalamus-pituitary-testis function in in vitro cell suspension system.

The effects of different neurotransmitters were tested in vitro on a hypothalamic tissue, collagenase-digested isolated anterior pituitary and Leydig cell suspension system by measuring the testosterone production of the Leydig cells. Neurotransmitters were used in concentrations of 0.25, 1.0, 2.5, 5.0, and 10.0 micrograms/ml incubation medium. Dopamine in doses of 1.0, 2.5, and 5.0 micrograms/ml increased the hypothalamic tissue-induced pituitary-testis activation, while it had no direct effect on pituitary and Leydig cells. Noradrenaline in the concentration range 2.5--10.0 micrograms/ml decreased the luteinizing-hormone-releasing-hormone (LHRH) sensitivity of the pituitary cells. 5.0 and 10.0 micrograms/ml 5-hydroxytryptamine decreased the testosterone production and the hCG sensitivity of the isolated Leydig cells. Carbamylcholine and pilocarpine had no action on the in vitro system at the different levels studied.

Effects of drugs on brain neurotransmitter and pituitary-testicular function in male rats.

The effects of different drugs influencing brain neurotransmitter contents have been tested on the pituitary-testicular function in male rats. L-dopa (200 mg/kg body weight, i.p.) increased the dopamine and noradrenaline contents of the hypothalamus, amygdala, striatum and mesencephalon, but it was ineffective as regards the 5-hydroxytryptamine contents of the same brain areas, and increased the plasma testosterone level. alpha-Methyl-p-tyrosine (250 mg/kg b.w., i.p.) decreased the dopamine and noradrenaline contents of these brain areas, but it was ineffective to 5-hydroxytryptamine, and decreased the plasma testosterone level. Diethyldithiocarbamate (400 mg/kg b.w., i.p. twice a day) increased the dopamine levels in the hypothalamus, amygdala, striatum and mesencephalon, decreased the noradrenaline contents in the same brain regions but had no effect on the 5-hydroxytryptamine contents of these brain areas or on the testosterone level in the peripheral blood. p-Chlorophenylalanine (300 mg/kg b.w., i.p.) decreased the 5-hydroxytryptamine contents of the different brain areas, while it had no effect on the dopamine and noradrenaline levels or on the plasma testosterone level. 5-Hydroxytryptophan (200 mg/kg b.w., i.p.) increased the 5-hydroxytryptamine contents of all brain areas studied, but was without effect on the dopamine and noradrenaline contents or the plasma testosterone level. The data suggest that both dopamine and noradrenaline may be involved in the regulation of the pituitary-testicular function, and the ratio of the two transmitters might be more important that their actual levels in definite brain areas.

Technique for study of hypothalamus (-) pituitary (-) testis function in vitro.

An in vitro system consisting of the rat hypothalamic tissue, the collagenase-digested isolated anterior pituitary cells and the Leydig cells, has been employed, where the testosterone production of the incubated Leydig cells was measured as the end point. The method appeared to be highly sensitive and specific in studying the functional interrelations of hypothalamus-pituitary-testis system. The sensitivity of the Leydig cells to hCG was 0.1--1.0 mU per 10(6) cells, and that of the anterior pituitary cells to LHRH responding with LH release was in the range of 0.1--1.0 ng per 10(6) cells. Two hypothalamic blocks can release a sufficient amount of LHRH to produce LH secretion in the pituitary cell preparation. The described technique seems to be a suitable in vitro approach for measuring the functional activity of the system studied and for evaluation of the sites of response to various external agents.