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Biomedical subjects

M Waloch

Publications and source records attributed to M Waloch.

11 recordsLinked to original sources

Melatonin inhibits PHA-stimulated chicken lymphocyte proliferation in vitro.

Many studies have shown that melatonin plays a fundamental role in neuroimmunomodulation. There are known differences between mammals and birds in immunomodulatory function of melatonin exerted in vivo. In present study the effect of exogenous melatonin on chicken lymphoid cell proliferation in vitro was examined. Melatonin alone (10(-10)M-10(-5)M) did not exert any effect on the proliferation of the chicken thymocytes, splenocytes and lymphocytes from the bursa of Fabricius. On the other hand, melatonin addition strongly inhibited the proliferation of PHA-activated thymocytes and splenocytes from young chickens. The effect of melatonin was hormone- and mitogen-(PHA) dose-dependent; the most pronounced effect was obtained at low PHA and melatonin concentrations i.e., 1.6-3.125 microg/100 microl of PHA and 10(-10) M-10(-7) M melatonin, respectively. Prior immunization of chickens with sheep red blood cells (SRBC) inhibited the proliferative response of splenocytes to the same dose of PHA and, consequently, the effect of melatonin addition was not observed. The results reported demonstrate a direct inhibitory effect of melatonin on in vitro activated chicken lymphocytes.

Animals↗

[Determination of specific immunoglobin G avidity in serodiagnosis of toxoplasmosis].

A total of 37 serum samples from pregnant women were examined for the avidity of toxoplasma IgG antibodies using commercially available enzyme immunoassay (Vidas Toxo IgG Avidity, bio Merieux). Low values of the avidity index were found for 4 samples and borderline ones were found in further 3 cases. Out of 19 serum samples showing the presence of IgG and IgM toxoplasma antibodies, 13 had high avidity index, including 9 samples from women in the first trimester of pregnancy. The results of examinations in these 9 cases allowed to exclude the possibility that toxoplasma infection was acquired during gestation. It is to be concluded that determinations of antitoxoplasma IgG avidity should become routine in every pregnant woman positive in the test for specific IgM antibody.

Animals↗

Cervical cerclage in the treatment of cervical incompetence in Zambian women.

Over a period of 5 years from January 1989 to October 1994, 207 patients with cervical incompetence were managed with Mac Donald's cervical cerclage at Nkana/Wusikili Mine Hospitals, Kitwe, Zambia. The incidence rate of cervical incompetence in our population was 1.47%. Our results confirmed a success rate of 90.8% as compared to 52.5% in previous pregnancies. This represents 159 (76.8%) full term pregnancies, 29 (14%) premature deliveries and 19 (9.2%) abortions. Post operation total survival rate was 87.4% with fetal salvage ratio of 1.68. We confirmed that optimum time to insert cerclage was 18 weeks and below. The possibility of having a mature baby in the group of low number previous abortions was significantly higher as compared to the group with a higher number of habitual abortions. Better pregnancy outcome was seen in low parity group (less than 2 previous deliveries) as compared to higher parity group. Our study confirms that cervical cerclage is a successful way in the treatment of cervical incompetence.

Abortion, Habitual↗

The effects of stimulation and lesion of raphe nuclei on luteinizing hormone release in estrogen-progesterone-treated ovariectomized rats.

A study was made of the effects of electrochemically stimulating (ECS) and destroying the midbrain dorsal and median raphe nuclei on the estrogen-progesterone- (EP) induced surge of pituitary LH release in ovariectomized rats. ECS and lesions were produced simultaneously with anodal direct current through a chronically implanted stimulation-lesion electrode. Blood for LH assay was collected through a chronic intra-atrial cannula positioned on the day of first treatment with progesterone. ECS of the raphe nuclei exerted a strong inhibition of the LH surge when compared with sham stimulation. On the second EP treatment the onset of the LH surge was advanced both in sham-stimulated animals and in rats with raphe lesions resulting from the anodal direct current of the initial ECS. It was suggested that this apparent facilitation of the LH surge on the second EP treatment was the results of reduced stress or an altered hormonal milieu and not a consequence of destroying the raphe nuclei. The results confirm in a chronic preparation that stimulation of raphe nuclei depresses the EP-induced LH surge and that subsequently in the absence of the raphe nuclei the LH response to EP treatment is apparently normal.

Animals↗

The effect of raphe nuclei lesions on the rat ovarian cycle.

The effects of lesions of the median raphe or dorsal raphe nuclei on ovarian cycle were studied in rats. Lesions involving raphe nuclei decreased forebrain 5-HT and 5-hydroxyindole acid (5-HIAA) concentrations. Rats with lesions of the raphe showed prolonged estrous phase as well as an increase in both the eosinophilic index and karyopycnotic index of the vaginal smears. Histological examinations revealed that lesions of both the dorsal and median raphe produced marked increase in the number of maturing and mature follicles as well as an increase in corpora lutea. The increase in uterine weight was also observed. Present results indicate that lesions of the ascending 5-HT neurons stimulate ovulation and cause an increase in the estrogenic activity. Thus, the 5-HT neurons of the raphe nuclei seem to inhibit ovulation probably due to inhibiting of the hypothalamic releasing hormones.

Animals↗

Effect of median raphe nucleus electrocoagulation and serotonin synthesis blockade on oestrogen receptor content of rat uterus.

The number of oestrogen receptors (OR) in rat uterus changes in relation to the cyclic function of the ovary. In the dioestrus phase the OR content of rat uterus is significantly greater than in the oestrus phase. Electrocoagulation of the median raphe nucleus causing in rats increased release of gonadotrophins and consequent disturbances in the cyclic ovarian function is associated also with changes in OR content of the uterus. These changes are, however, not analogous to those observed in the normal sexual cycle. In the oestrus phase a very high accumulation of OR is found in the uterus, while in the dioestrus phase OR are barely detectable. Serotonin synthesis blockade with p-CPA, which is associated with an increase in the number of maturating and mature follicles in the ovary and dioestrus phase prolongation leads to a striking increase in the number of OR in the uterus.

Animals↗