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A Lewiński

Publications and source records attributed to A Lewiński.

At least 37 records · Page 2Linked to original sources
PubMed1994

Changes of 3H-thymidine incorporation into DNA and thymidine kinase activity in rat thyroid lobes, following their exposure to neuropeptide Y.

The effects of neuropeptide Y (NPY) on 3H-thymidine incorporation into DNA of rat thyroid lobes in a 4 h incubation, and on the activity of thymidine kinase (TK) in the homogenates of thyroid lobes in vitro, as well as the influence of thyrotropin (TSH), applied alone or together with NPY, were investigated. The effects of NPY were dependent on the concentration used. Neuropeptide Y, in the lowest and the highest concentrations, decreased both the incorporation of 3H-thymidine to DNA and TK activity, and when used in intermediate concentrations NPY did not significantly affect the processes examined. Thyrotropin decreased TK activity and revealed a tendency towards lowering 3H-thymidine uptake, the latter effect being not statistically significant. NPY (10(-10) M) used together with TSH, produced an increase of 3H-thymidine incorporation into DNA, when compared with controls and the TSH-exposed group. Following the joint exposure to NPY and TSH, TK activity declined.

Animals↗
PubMed1994

Effects of vasoactive intestinal polypeptide on the growth processes in rat thyroid lobes: studies ex vivo in vitro.

The effects of intravenous (i.v.) injections of vasoactive intestinal polypeptide (VIP) and intraperitoneal (i.p.) injections of thyroid-stimulating hormone (TSH, thyrotropin) on 3H-thymidine incorporation into the DNA of rat thyroid lobes incubated, after collecting, in vitro, were investigated. The animals of groups 1-6 were injected with the following substances: group 1, 0.9% NaCl; group 2, 2 IU TSH (i.p.); group 3, 10(-12) mol VIP; group 4, 10(-10) mol VIP; group 5, 10(-8) mol VIP; and group 6, 10(-8) mol VIP + 2 IU TSH (i.p.). The rats of each group were divided into three subgroups, and sacrificed after 6, 12 or 24 h from the time of injection. For group 1, the additional control group zero was used, and these controls were sacrificed immediately after i.v. injections of 0.9% NaCl at zero time. After decapitation the thyroid lobes were collected and then incubated for 4 h in RPMI 1640 medium in the presence of 3H-thymidine, 15% FCS and Hepes buffer. In all groups and at all times an increase of 3H-thymidine incorporation occurred; the stimulatory effect of VIP (in all doses) was stronger than that of TSH; the rate of 3H-thymidine incorporation after injections of both VIP and TSH (group 6), was higher than the rates following injections of VIP alone (group 5) or TSH alone (group 2).

Animals↗
PubMed1994

Melatonin-induced decrease of the size of thyrocyte nuclei in rat thyroids incubated in vitro.

The mean volume, intersection area and perimeter of thyrocyte nuclei in rat thyroid lobes incubated with melatonin (Mel), thyrotropin (TSH) or with both substances together, were investigated. The measurements were carried out using a computer system for karyometric examination. Melatonin in concentrations of 10(-8) M, 10(-10) M and 10(-12) M significantly decreased the mean nuclear volume and intersection area of thyrocytes (p < 0.01); the mean perimeter of thyrocyte nuclei was significantly decreased by melatonin in concentrations of 10(-10) M and 10(-12) M (p < 0.01). TSH (20 mIU/ml), when applied alone, significantly decreased the mean volume, intersection area and perimeter of thyrocyte nuclei (p < 0.01). TSH generally did not counteract the melatonin-induced decrease of thyrocyte nuclei except for 10(-10) M melatonin concentration when TSH increased the mean nuclear perimeter (p < 0.01) and slightly enlarged the mean volume (p < 0.05), compared with Mel alone. The results suggest an inhibitory influence of melatonin on thyroid follicular cell activity, and are in compliance with earlier observations.

Animals↗
PubMed1993

Effects of pinealectomy and melatonin administration on certain indices of ovarian hyperplasia and/or hypertrophy in rats with both ovaries intact or after unilateral ovariectomy.

In earlier studies from other laboratories it was shown that melatonin decreased ovarian weight in rats and inhibited compensatory hypertrophy of the remaining ovary after unilateral ovariectomy. This study was designed to examine the influence of melatonin on certain indices of ovarian hyperplasia and/or hypertrophy in adult female rats with both ovaries preserved and with either an intact pineal gland or with the pineal gland removed (pinealectomy, PX) or, finally, in sham-PX animals. Similar studies were conducted on rats after unilateral ovariectomy, referring the examined parameters to the remaining intact ovary. The studies included mitotic activity of granulosa layer cells and corpus luteum cells, ovarian weight, ovarian cross-sectional area, cross-sectional area of the granulosa layer of all the Graafian follicles and the cross-sectional areas of the corpora lutea, visible on the ovarian cross-section. On the basis of results, we conclude that: 1) the effect of PX on the processes of ovarian hyperplasia and hypertrophy may vary; analogously, exogenous melatonin administration may influence ovarian hyperplasia and hypertrophy in different ways; 2) PX and exogenous melatonin may, under certain conditions, exert similar biological effects, even synergistic effects; 3) melatonin inhibits ovarian growth processes, while the effects of PX are variable; 4) the results indicate that in experiments performed on rats, with the use of two control groups, i.e., intact and sham-PX, melatonin effects on these two groups may differ.

Animals↗
PubMed1993

The usefulness of computer-aided karyometric examination in preoperative differentiation of follicular neoplasms of the thyroid gland.

Fine-needle aspiration biopsy (FNAB) is the most important procedure in preoperative diagnosis of thyroid neoplasms. However, routine cytological examination is insufficient for differentiation between follicular adenoma and follicular carcinoma. Therefore, we decided to assess the usefulness of karyometric analysis in the examination of aspirates from these neoplasms. Morphometric analysis was performed with the use of the computer system for karyometric measurements--"Karyometry Manager" ver. 1.2. We examined cytological smears derived from 26 patients. In 10 of them a nodular goitre was diagnosed in both cytological and histopathological examinations. In the other 16 patients, "follicular neoplasms" were found in cytological examination. These proved to be follicular adenomas (8 cases) and follicular carcinomas (8 cases) on histopathological examination. The following morphometric parameters were measured in 100 nuclei per smear: volume, intersection area, perimeter, convexity coefficient and shape coefficient. We found that: 1) the mean volume and the mean intersection area of thyrocyte nuclei from follicular carcinomas were significantly (p < 0.001) greater than those of nuclei from adenomas or nodular goitres; 2) the mean perimeter of thyrocyte nuclei from follicular carcinomas was significantly greater than the mean perimeter of thyrocyte nuclei from follicular adenomas (p < 0.025) and nodular goitres (p < 0.001); 3) the mean nuclear area of thyrocytes from follicular adenomas was significantly greater than that of thyrocytes from nodular goitres (p < 0.05). Our results show that karyometric analysis can be useful in cytological differentiation of follicular neoplasms.

Adenocarcinoma, Follicular↗
PubMed1993

Occurrence of goitre in relation to iodine deficiency in school children in Lódź City, the Lódź metropolitan area and in Piotrków, Sieradz, Płock, Włocławek, Radom and Skierniewice Voivodships (Lódź coordinating center).

This paper presents the results of studies performed within the Applied Project of the Ministry of Health and Social Welfare and of the Committee for Scientific Research: "Studies on Iodine Deficiency in Poland", including the school children in Lódź City and seven voivodships of the Central Poland. According to the results, the analyzed regions can be regarded as areas of goitrous endemia of a moderate degree (the goitre was found in 32.7% of examined population); the same regions can also be classified among the regions of mild iodine deficiency (the mean iodide concentration in urine was 64.0 micrograms/l). The obtained results prove the to-date's iodine prophylaxis to be not entirely efficient in the areas of interest, demanding an effective model of iodine complementation in diet to be designed.

Adolescent↗
PubMed1993

[Role of melatonin in human physiology and pathology. I. Circadian rhythm of melatonin secretion. Involvement of melatonin in reproductive physiology. Melatonin and hypothalamic-pituitary-adrenal cortex axis].

This paper summarizes the recent knowledge on the role of melatonin in humans. The first part of the present review considers the following aspects: circadian rhythm of melatonin excretion, melatonin in body fluids, melatonin influence on sexual maturation, changes of melatonin blood concentration during the menstrual cycle and pregnancy, and the influence of melatonin administration on prolactin concentration. Current views on the relationship between melatonin and the hypothalamo-pituitary-adrenal cortex axis, as well as on changes of melatonin concentration during hypothyreosis, hyperthyreosis, and hyperparathyroidism are also discussed.

Circadian Rhythm↗
PubMed1993

[Role of melatonin in human physiology and pathology. II. Involvement of melatonin in pathogenesis of affective and chronobiological disorders. Melatonin and the aging process. Melatonin and neoplasms].

In the second part of this review the role of melatonin in pathogenesis of affective diseases and chronobiological disorders is discussed. Current views on melatonin involvement in aging are presented. Clinical experiments on the possible usefulness of melatonin in treatment of various types of cancers and hypothetical mechanisms of oncostatic influence of melatonin are also summarized.

Aging↗
PubMed1993

Effects of the pineal gland on the growth processes of Guerin epithelioma in male Wistar rats.

The effects of pinealectomy (PX) and melatonin (Mel) administration on the growth processes of Guerin epithelioma, a malignant tumour derived from spontaneous cancer in Wistar rat uterus, was investigated in five groups of male rats. The mean life span of the rats bearing Guerin tumours (GT) and subjected to PX was shorter than in animals with an intact pineal gland. Mel did not affect the lifespan in rats with intact pineals or in those subjected to PX. Mel decreased the mitotic activity of GT cells in rats with and without the pineal gland. Pathomorphological examination revealed high malignancy of the primary tumour but no metastases. The results confirmed the important role of the pineal gland in 'oncostasis'.

Animals↗
PubMed1993

Effects of a single pentagastrin injection on diamine oxidase activity in the rat intestinal mucosa.

The effect of a single injection of pentagastrin on diamine oxidase (DAO) activity in the rat intestinal mucosa was examined. The animals of subsequent groups were sacrificed by decapitation at 6, 12 and 24 h after the administration of pentagastrin or 0.9% NaCl (controls). Diamine oxidase activity was also tested in entire animals. The intestinal fragments were rinsed with 0.9% NaCl. The mucosal scrapings were frozen in liquid nitrogen. Diamine oxidase activity increased in the 24 h after the administration of pentagastrin, when compared with respective controls. No significant differences at other times were evident. The present data are in agreement with the hypothesis that DAO is an enzyme involved in the negative feedback control mechanism of intestinal mucosa cell proliferation.

Amine Oxidase (Copper-Containing)↗
PubMed1992

Inhibitory influence of late afternoon melatonin injections and the counter-inhibitory action of melatonin-containing pellets on thyroid growth process in male Wistar rats: comparison with effects of other indole substances.

Previous studies performed in our laboratory indicated that melatonin, when administered in late afternoon (1600-1800) as s.c. injections for 10 days, exerted an inhibitory effect on thyroid growth in mice and Sprague-Dawley rats. The goal of the present study was to examine the effects of melatonin and other indole substances (5-methoxytryptophol, N-acetylserotonin, 6-methoxytryptamine), administered for 10 days, for either 4, 8, or 10 weeks, on thyroid growth processes in adult male Wistar rats. We have also compared the action of melatonin administered in late afternoon as s.c. injections with effects of the melatonin-released chronically from s.c. implanted beeswax pellets containing 1 mg of the hormone. Additionally, the effects of melatonin injections in animals with the pineal gland removed and in thyroid stimulating hormone (TSH)-injected rats have been studied. We examined the mean mitotic activity rates (MMARs) of thyroid follicular cells (TFC) and the wet thyroid weights. We concluded that melatonin, of the examined substances, is the most potent inhibitor of thyroid growth; the hormone reduced the MMAR of TFC and the thyroid weight at all time-points. 5-Methoxytryptophol, like melatonin, exerted the inhibitory influence on the mitotic activity; however, it did not affect thyroid weight. The influence of other indole substances was much less pronounced. It was shown that melatonin-pellets prevented the inhibitory effect of late afternoon melatonin injections on thyroid growth processes. This observation is consistent with results of other authors concerning the counter-antithyroid effect of melatonin on thyroid hormone secretion. Pinealectomy revealed the stimulatory effect on thyroid growth processes, while melatonin treatment reversed the effect of the surgery.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Effects of pineal-derived indolic compounds and of certain neuropeptides on the growth processes in the thyroid gland.

The aim of the present study was to examine the effects of melatonin (Mel) and of pinealectomy (PX) [in a long-term experiment in vivo - 10 weeks], as well as of Mel and N-acetylserotonin (NAc-5HT) [in experiments ex vivo in vitro and in vitro], on the rat thyroid growth processes. Additionally, the incubations in vitro of rat thyroid lobes with 3H-thymidine, in the presence of TSH, vasoactive intestinal polypeptide (VIP), VIP-antagonist ([4Cl-D-Ph6, Leu17]VIP), somatostatin (SS), all the substances used separately or jointly in combinations, were performed. It was shown that: (a) Mel--administered in late afternoon injections--decreased, while PX increased examined indices of thyroid growth in vivo, (b) Mel--administered in s.c. implanted pellets--reversed the inhibitory effect of Mel injections, (c) in experiments ex vivo in vitro and in vitro, the inhibitory effect of Mel revealed only for the lowest applied dose/concentration of the hormone, (d) NAc-5HT showed no effect, (e) VIP decreased 3H-thymidine incorporation into DNA of thyroid lobes in vitro and enhanced the inhibitory effect of SS on the process in question, (f) VIP-antagonist failed to reverse the inhibitory action of VIP on the thyroid growth.

Animals↗
PubMed1992

Effects of calcitonin and calcitonin gene-related peptide on 3H-thymidine incorporation into DNA of rat thyroid lobes in vitro.

The effects of a 4 h incubation of rat thyroid lobes, in the presence of calcitonin (CT) and calcitonin gene-related peptide (CGRP) on the incorporation of 3H-thymidine into DNA, were investigated. In other groups the thyroid lobes were incubated during exposure to CT and thyrotropin (TSH), and to CGRP together with TSH. All concentrations of CT (10(-6)-10(-8) M) revealed a tendency towards lowering 3H-thymidine uptake, but the effect was not statistically significant. The influence of CGRP was dose-dependent; the lowest concentration of CGRP (10(-9) M) significantly enhanced DNA synthesis in the incubated rat thyroids; an intermediate dose of the peptide (10(-8) M) had no effect, while the highest concentration of CGRP (10(-7) M) decreased 3H-thymidine incorporation. Calcitonin (10(-7) M), as well as CGRP (10(-8) M), suppressed the stimulatory effect of TSH on 3H-thymidine incorporation.

Animals↗
PubMed1992

[Comparative analysis of fine needle aspiration biopsy results performed in the laboratory of thyroid diseases, University School of Medicine in Lodz in 1985-91 with results of postoperative histopathologic examinations].

From 1985 to 1991 there were 5889 fine-needle aspiration biopsies of thyroid performed in our laboratory. 703 cytological diagnoses based on biopsy specimens taken from 679 patients, were compared with the results of postoperative histopathological examinations. There were 14% non-diagnostic biopsies. The statistical analysis was performed considering difficulties in differentiation between follicular adenomas and follicular carcinomas. Difficulties in evaluation of biopsies of cystic lesions were also considered. The results of cytological and histopathological examinations were agreeing with one another in 88% cases. In regard to diagnosis of malignant neoplasms, the sensitivity of the cytological investigation was equal to 63% and the specificity equaled to 90%. While considering detection of papillary carcinomas, the sensitivity was equal to 67%. Our results are in a compliance with the view, that the fine-needle aspiration biopsy is a useful method in a preoperative diagnosis of thyroid lesions.

Biopsy, Needle↗
PubMed1992

[Factors regulating growth processes in the ovary].

This paper summarizes the recent knowledge on the factors stimulating or inhibiting the ovarian growth. In the present review the following factors influencing growth processes in the ovary are discussed: gonadotropins, sex steroids, prolactin, renin, angiotensin II, atrial natriuretic factor (ANF), growth hormone, insulin, prostaglandins, pineal indoleamines, tissue growth factors and others. The role of nervous system is also described in the study. Not only gonadotropins and other stimulatory factors but also inhibitory agents, e.g., melatonin should be considered in the ovarian growth regulation. The hypertrophic and/or hyperplastic processes in the ovary seem to be dependent on either the excess of stimulatory agents or the deficit of the growth inhibitors.

Atrial Natriuretic Factor↗