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Biomedical subjects

J Zák

Publications and source records attributed to J Zák.

At least 19 recordsLinked to original sources
PubMed2000

Effect of growth hormone and pamidronate on bone blood flow, bone mineral and IGF-I levels in the rat.

So far it is not known whether the growth hormone (GH) has an effect on the local blood circulation in bones. Using male rats we studied the local blood circulation in the tibia and the distal end of the femur (by means of the uptake of 85Sr-microspheres), the density and ash weight of the tibia, the urinary excretion of pyridinoline (PD) and deoxypyridinoline (DPD) as an indicator of bone resorption and the blood levels of IGF-I after the administration of human GH (4 mg/kg s.c. daily for 4 weeks) and/or bisphosphonate pamidronate (Aredia, CIBA-Geigy, administered in the dose of 3 mg/kg i.p. on day 1, 2, 9 and 10). The rats were divided into four groups: 1. controls, 2. GH, 3. pamidronate, 4. GH plus pamidronate. After the administration of GH, we observed a significant increase in bone blood flow (and in the uptake of 85Sr-microspheres), a decrease in the density and ash weight of the tibia and increased urinary excretion of PD and DPD; IGF-I levels in the blood were non-significantly elevated. Simultaneously administered pamidronate inhibited all significant effects of GH and it also decreased the IGF-I levels in rats treated with GH. After the administration of pamidronate itself the bone density and ash weight of the tibia were increased and urinary DPD excretion was decreased. In view of the known vascular effects of IGF-I, we assume that the increase in bone blood flow after the administration of GH and its reduction after simultaneous administration of pamidronate could be mediated by the changes of IGF-I blood levels, although the effect of pamidronate on IGF-I is still not clear. Regarding the role of blood circulation in rat bones, we consider that our present results are further evidence for the relationship between the blood circulation in bones and bone resorption, although these results do not show how active is bone blood circulation in the regulation of bone tissue metabolism.

Amino Acids↗
PubMed1999

[Overview of the pathophysiology, diagnosis and treatment of bone metastases].

The author presents a review on the most frequently encountered sources of malignant secondaries in bones, on their sites and their possible detection. Part of the review deals with the mechanism of deposition of metastatizing elements in bones and explains the basic sources of tumourous osteolysis. Finally the author mentions some recent trends as regards approaches to treatment of bone metastases.

Bone Neoplasms↗
PubMed1999

[Laparoscopically-assisted endoscopic polypectomy].

OBJECTIVE: Make it possible to implement safe polypectomy of polyps of the large intestine with a diameter at the base greater than 1 cm located in the intestinal lumen above the peritoneal fold. METHOD: After laparoscopy under general anaesthesia endoscopic polypectomy is performed under laparoscopic control. The large intestine is sutured to the site of the base of the removed polyp using laparoscopic technique. RESULTS: Removal of large polyps of the large bowel with a base diameter greater than 1 cm without the need of laparotomy. CONCLUSION: Laparoscopically assisted polypectomy is a safe and effective method for the removal of large bowel polyps with a large base.

Colonic Polyps↗
PubMed1998

[Relation between local blood flow and bone mineralization indicators in the tibia of female rats].

The results presented contribute to the still unclarified question of the role of bone blood flow in the metabolism and mineralization of the bone tissue. We investigated correlation relationships between 85Sr-microsphere uptake (in % dose per g) or local blood flow (in ml/min per g) and density or ash weight (in g per ml of bone tissue) in the tibia of female rats. In four experiments a total of 16 correlations was computed. The following relationships were found statistically significant (p < 0.05): in exp. A (20 intact females): microsphere uptake--ash weight, blood flow--density, blood flow--ash weight, in exp. B (oophorectomy 4 weeks before the experiment, 28 rats): microsphere uptake--ash weight, blood flow--density, blood flow--ash weight, in exp. C (estradiol benzoate 1 mg s.c. twice a week for 4 weeks, 40 rats): microsphere uptake--density, microsphere uptake--ash weight, blood flow--density, in exp. D (20 oophorectomized females on estradiol): microsphere uptake--ash weight, blood flow--ash weight. The results support the hypothesis of an interconnection between the mineralization of bone tissue and local bone blood flow.

Animals↗
PubMed1998

Effect of pamidronate on bone blood flow in oophorectomized rats.

In connection with the known inhibitive action of bisphosphonates on bone resorption we were interested in their possible influence on bone blood flow (BBF). We determined BBF (85Sr-microsphere uptake in the tibia, distal femur and diaphysis of femur), cardiac output, density and ash weight of the tibia, as well as 24-h incorporation of 45Ca and 3H-proline into the tibia. Pamidronate (Aredia, CIBA-Geigy, Switzerland) was administered to sham-operated or oophorectomized (OOX) female rats in doses of 0.6 mg i.p. 2 days a week for 4 weeks. 85Sr-microsphere uptake was increased after OOX in the tibia and distal femur, simultaneous pamidronate administration significantly suppressed this increase below the control level. In addition, pamidronate inhibited the 24-h incorporation of 45Ca and 3H-proline in sham-operated females and suppressed the incorporation of 3H-proline that was increased after OOX. Bone density and ash weight were significantly increased after pamidronate administration in both sham-operated and OOX rats. The results of both experiments showing a significant effect of pamidronate on BBF and incorporation of 45Ca and 3H-proline require further verification and elucidation.

Animals↗
PubMed1997

[Endoscopic and surgical treatment of acute bleeding gastroduodenal ulcers].

One of the basic problems of the treatment of acute bleeding from gastroduodenal ulcers concerns the correct timing of individual therapeutic steps. From 1992 to 1990 the I. Surgical Clinic in Brno performed the total of 438 urgent gastrofibroduodenoscopies, the most frequent finding being bleeding from the lesions in the area of the duodenal bulb. Endoscopic stoppage of bleeding was successful in 87.7% of patients. Failures in stopping the bleeding occurred in 18 cases and lead to urgent surgical intervention. On the basis of gained experience we recommend the following algorhithm in patients with acute bleeding from gastroduodenal ulcers: urgent endoscopy-endoscopic stoppage of bleeding. Relapse of bleeding requires endoscopic control with a new attempt of endoscopic therapy, in the case of failure it is urgent to intervene surgically. (Tab. 4, Ref. 14.)

Acute Disease↗
PubMed1997

[DHEA: another hormonal modulator of bone blood flow in rats].

Dehydroepiandrosterone (DHEA) is a steroid with important effects on the bone tissue. We tried to check up if it influenced also the bone blood flow (similarly as estradiol and testosterone). We administered DHEA (Sigma) dissolved in dimethylsulphoxide s.c. three times weekly for four weeks in the doses of 15-20 mg per rat on 125 mg/kg body weight to female rats--sham-operated or oophorectomized (OOX). In two experiments (A and B) we ascertained the uptake of 85Sr-microspheres, local blood flow, cardiac output, density and ash weight of the burned tibia, in the third experiment (C) 24 hour incorporation of 45Ca and 3H-proline into the bone. The 85Sr-microsphere uptake in the tibia was elevated after OOX in both experiments A and B; this increase was inhibited completely (and statistically significantly versus the OOX group) by the administration of DHEA. Similar and also significant reactions were found in the microsphere uptake values in the distal end of femur. No significant changes could be demonstrated in the diaphysis of femur and calvaria as well as in the cardiac output, output, blood pressure and heart rate. The incorporation of 45Ca and 3H-proline into the tibia (experiment C) was significantly increased after OOX. The administration of DHEA inhibited this increase significantly in the values of 3H-proline. The density of tibia in both experiments A and B and ash weight of tibia in experiment A, suppressed after OOX, were significantly increased after the administration of DHEA to OOX females. The results show that also DHEA--in the experimental conditions used--has similar effect on the bone blood flow as estradiol and testosterone.

Animals↗
PubMed1995

[Histomorphometry of bone in clinical practice and research].

Short overview of importance and principles of histology and histomorphometry of bone tissue patterns performed in IIIrd internal clinic since 1978 is described. Since the beginning, 736 bone biopsy patterns were taken. Generally there are two groups of indications for bone tissue investigation: differential diagnosis of osteologic or hematologic diseases, or investigational indication in a research study. Short overview of morphometric results, gained in IIIrd internal clinic is stated. Histomorphometric parameters of acromegalic and normal trabecular bone were compared and results and consequences for architecture of trabecular bone are described. No correlation between levels of somatotropin or somatomedin C and histomorphometric parameters was found out. Principles of further investigation in IIIrd internal clinic are outlined.

Acromegaly↗
PubMed1994

[Local factors in bone remodeling. II. Factors stimulating bone resorption].

In this article, author gives a surveillance of factors, locally produced in bone tissue, which stimulate bone resorption. Production of local factors in bone tissue cells is initiated by various hormones, including some systemic hormones. Some new hypothesis about relation of systemic hormones activity and local bone tissue factors production are described including hypothesis about function of estrogens on bone.

Animals↗
PubMed1992

[Changes in hypertrophy and diastolic left ventricular function during hypertension therapy].

The authors examined a group of hitherto not treated patients with primary hypertension and hypertrophy of the left ventricle. By means of echocardiography and isometric loading they investigated the effect of treatment on the left ventricular morphology and function. Despite long-term normalization of casual and loading values of the blood pressure the authors did not observe a significant regression of LV hypertrophy. The authors did not find a relationship between the casual blood pressure and weight of the left ventricle with exception of the diastolic pressure after a load. The indicators of diastolic function did not correlate with the weight of the left ventricle but with changes of the end diastolic volume and blood pressure.

Adult↗
PubMed1990

[Hormones in bone metabolism. I. Calcitropic hormones].

The review concentrates on calcitropic hormones (parathormone, calcitonin and the active metabolite of vitamin D-1,25-dihydroxyvitamin D3) and their action on bone remodeling. Attention is drawn to mechanisms of their action on the bone cell, on their manifestations in histology of osseous tissue and clinical symptomatology in pathological conditions. Attention is also drawn to the possible therapeutic application of calcitropic hormones.

Bone and Bones↗
PubMed1990

[Hormones in bone metabolism. II. Other systemic hormones].

The authors present a review on a number of systemic hormones involved in bone metabolism. At the same time they demonstrate mechanisms of their action on the cellular, tissue and skeletal level. Attention is drawn to the participation of these hormones in the pathology of bone and other organs and the necessity to protect the skeleton during their therapeutic use in other than osteologic indications.

Adrenal Cortex Hormones↗
PubMed1990

[Interrelation between static parameters of trabecular bones in acromegaly, the STH levels and the duration of the condition. Histomorphometric study].

To evaluate trabecular bone formations of active acromegalic patients the authors used the method of histomorphometry and correlated the calculated variables of the trabecular volume (V), osteoid volume (Vos), osteoid surface (Sf) and width of the osseous trabeculum (MTT) with STH levels, the patients' age and the period of the acromegalic process. No correlations were found between Vos, Sf, MTT and STH levels, age and the length of the case-history. There were negative correlations (p less than 0.05) between the trabecular volume (V) and the period of the case-history and trabecular volume (V) and the patients' age. From the results it may be concluded that STH does not influence the balance between resorption and formation of the acromegalic spongiosa in favour of formation.

Acromegaly↗
PubMed1990

[Comparative histomorphometric study of acromegalic spongy bone. Formative static parameters].

The authors used static histomorphometric parameters obtained by processing of bioptic bone specimens for comparison of normal and acromegalic spongious bone. Parameters of the bone volume (V), osteoid volume (Vos), the extent of osteoid bone surfaces (Sf) in the two groups do not differ statistically. The two groups do not differ as to age distribution. The width of bone trabeculae is greater in acromegalic bone; the difference as compared with normal bone specimens is statistically significant (p less than 0.05). The authors conclude that STH in acromegalics subjects does not stimulate osteoid production in trabecular bone to shift the balance between bone resorption and formation significantly in favour of formation. Only restructuring of trabecular acromegalic bone occurs.

Acromegaly↗
PubMed1990

Actual contribution of bronchology to the management of lung diseases.

The paper reports on bronchoscopic examinations carried out at the Department of Bronchoscopy, Clinic of Tuberculosis and Respiratory Diseases, in the period of 1977 to 1987. The applicability of individual bronchoscopic methods is evaluated. Advantages and limitations of the rigid bronchoscope and the fibrescope, techniques of removal of material for cytologic and other examinations are discussed. It is stressed that the most frequent indication for bronchoscopy is suspected bronchial carcinoma with increasing incidence.

Bronchoscopy↗