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Biomedical subjects

A Kádár

Publications and source records attributed to A Kádár.

At least 19 recordsLinked to original sources
PubMed2001

Development of atherosclerosis and plaque biology.

Atherosclerosis is a leading issue in mortality and morbidity in the civilized world. A number of hypotheses for atherogenesis indicate the complexity of initiation and development of this multifactorial disease. Morphologic types of lesions have long since been studied in order to understand plaque evolution and determinants of plaque complication, a frequent cause of acute ischemic accidents. Chemical and pathophysiological studies defined the wide spectrum of molecular interactions between cellular elements of atherosclerotic lesions. Recently, molecular biologic investigations provide a deeper insight into genetic predispositions for the disease and have widened our understanding of the pathogenic mechanisms. Until we can diminish the high prevalence of the disease, precise information is needed on the evolution of atherosclerosis in order to slow progression, select optimal therapies and prevent plaque complications and their consequences.

Arteriosclerosis↗
PubMed2001

Connexin 43 expression in rat aortic smooth muscle after ovariectomy and hormonal replacement.

The purpose of this study was to determine the effects of ovariectomy and long-term combined sexual hormone replacement on the gap junctional protein, connexin 43 (Cx43) of aortic medial smooth muscle cells in rats. Twenty non-pregnant mature Wistar female rats were divided into five groups (four animals in each group). Group A underwent ovariectomy, Group B underwent ovariectomy and received estradiol propionate, Group C underwent ovariectomy and received medroxyprogesterone acetate and Group D underwent ovariectomy and received both hormones. Group E was sham-operated and used as control. After 15 weeks of treatment, thoracic aortas were removed and immunohistochemistry was carried out using a specific fluorescent antibody against Cx43. Tissue sections were examined by confocal laser scanning microscopy and analysed by the Scion Image program. All five different groups had the same distribution and extent of Cx43 in the aorta. Neither the ovariectomy nor the hormone replacement had any effect on the Cx43 expression of aortic smooth muscle cells in rats as compared to control animals. These results indicate that sexual steroids do not influence the gap junctional protein Cx43 of the medial layer of aorta in rats. They may suggest that the beneficial effects of estrogen are not mediated via gap junctions in the human aorta either.

Animals↗
PubMed1999

Tenascin expression and angiogenesis in breast cancers.

The expression and the distribution of tenascin as well as the extent of blood vessel formation (angiogenesis) were investigated in 70 invasive human breast carcinomas. Formalin-fixed, paraffin-embedded specimens were stained with monoclonal antibody against tenascin-C (DAKO and Biogenex). Anti-CD31 antibody (Biogenex), an acknowledged marker of stromal angiogenesis, was used to detect endothelial cells. Tenascin immunostaining was positive in the tumours around the persisting normal ducts, around tumour-cell nests, in the neostroma, in some tumour cells, and it was found in or around vascular channels. Tumour vascularity was assessed by quantitative vascular grading (Chalkley point count) and was related to the localization and intensity of tenascin immunoreactivity. 19 tumours (27.1%) were scored as low, 35 (50%) as medium, and 16 (22.9%) as having a high vascular grade. The positive correlation between the vascular grade and the tenascin immunopositivity in tumour stroma was observed. Our results suggest that tenascin expression may be associated with endothelial cell activation and may play an important role in tumour angiogenesis.

Adult↗
PubMed1999

World Health organization (WHO) and the World Heart Federation (WHF) pathobiological determinants of atherosclerosis in youth study (WHO/WHF PBDAY Study) 1986-1996. Histomorphometry and histochemistry of atherosclerotic lesions in coronary arteries and the aorta in a young population.

BACKGROUND AND AIM: The present work is a chapter in an investigation directed by the World Health Organization on the Pathobiological Determinants of Atherosclerosis In Youth (WHO-PBDAY). Our aim was to study the development of atherosclerotic lesions in a young population. METHODS AND RESULTS: Samples of left anterior descending coronary artery (LDC) and thoracic (TA) and abdominal aorta (AA) from five Collaborating Centres (Budapest/Hungary, Havana/Cuba, Heidelberg/Germany, Mexico City/Mexico, Peradeniya/Sri Lanka) of 214 subjects who died aged 15 and 34 were analysed at the Budapest Reference Centre. Slides stained with haematoxylin-eosin and with stains for extracellular matrix were quantitatively and qualitatively evaluated. Mean intima/media (I/M) ratio and the prevalence of type III-IV lesions (preatheroma; atheroma; calcified and fibrous atheroma) were determined and compared in different risk factor (high blood pressure, smoking) groups. High I/M ratio was found in the LDC and type III-IV lesions were frequently found both in the LDC and in the AA. I/M ratio and the occurrence of type III-IV lesions increased in all arteries by age. Atherosclerotic lesions in men were more severe, particularly in the LDC. Geographic origin had a limited effect on the histologic lesion parameters. Appearance of type III-IV lesions was associated with substantially different extracellular matrix changes. Myoelastic layer formation was found in each artery in both early and type III-IV lesions. Hypertension was associated with higher prevalence of type III-IV lesions in all arteries, in particular, in the TA; smoking showed a significant effect on the AA only. CONCLUSIONS: Atherosclerotic lesions were found in many of these young subjects. The effect of hypertension and smoking on their development suggests that control of risk factors, beginning in early adolescence, could help to prevent cardiovascular diseases.

Adolescent↗
PubMed1996

Detection of Chlamydia trachomatis in the prostate by in-situ hybridization and by transmission electron microscopy.

Chlamydia trachomatis infection has been investigated in the prostate gland using in-situ DNA hybridization and transmission electron microscopy. Sixty-four samples of tissue removed by trans-urethral resection or by open surgery from men with benign prostatic hypertrophy (BPH), were examined histologically and 20 of the cases were found to be positive for mononuclear cell infiltration. Some samples were then investigated using in-situ hybridization and transmission electron microscopy. Out of 20 tissue samples with mononuclear cell infiltration, nine were found to be positive for C. trachomatis infection.

Chlamydia Infections↗
PubMed1995

[Detection of Chlamydia trachomatis in chronic prostatitis by in situ hybridization (preliminary methodical report)].

(Preliminary methodical report). In situ hybridization of Chlamydia trachomatis in formalin fixed, paraffin embedded specimens from the Urology Clinic were performed in 2nd Department of Pathology Semmelweis University of Medicine by a biotin labelled DNA probe. Chlamydia trachomatis is suspected to be responsible for the chronic abacterial inflammation of the prostate besides Ureaplasma urealyticum and Mycoplasmae. According to our retrospective study out of 79 biopsy specimens 34 had the diagnosis of chronic abacterial prostatitis. We examined 11 specimens of them. Bacteria were not identified. Three specimens were positive for Chlamydia trachomatis which were improved by transmission electron microscope. The age of patients was between 59 and 81 years. The detection of chlamydia infection rises the suspicion of a "healthy" career and especially at younger age could cause Chlamydia trachomatis associated genital disease. The undiagnosed and untreated diseases may lead to infertility.

Adult↗
PubMed1994

[A case of successful operation of left atrial myxoma causing cerebral embolism].

The authors describe the case report of a young woman in whom a left atrial myxoma causing cerebral embolism was diagnosed by echocardiography. On the ninth day after the development of neurologic symptoms the tumor was excised by an emergency intervention. After the operation the condition of the patient improved considerably. In connection with the case the authors underline the role of echocardiography in the detection of sources of embolism.

Adult↗
PubMed1992

[Comparison of ST depression and various exercise test indices in the diagnosis of coronary stenosis].

UNLABELLED: Various modifications and refinements have been proposed to improve the diagnostic accuracy of standard ST-segment criteria for identifying coronary artery disease using exercise testing. To ascertain if the treadmill exercise score (TES), the ST integral, or the ST/HR index are significantly better markers for coronary disease the standard ST analysis, measured visually or by computer, a retrospective study of 173 male patients was performed. Exclusions were clinical or electrocardiographic evidence of prior myocardial infarction, left ventricular hypertrophy, left bundle branch block, or resting ST segment depression on their baseline electrocardiogram, digitalis, previous revascularization procedure or any significant valvular or congenital heart disease. Ninety-six patients (55.5%) had at least one epicardial coronary stenosis (more than 70% diameter stenosis). Cutpoints were chosen for each method, that maximized their best combination of sensitivity and specificity. There were no statistically significant differences between any of the five methods (TES, ST integral, ST/HR index, standard and computer ST analysis) for identifying any coronary disease. CONCLUSION: careful visual or ST-segment analysis continues to be the simplest as well most effective marker for coronary disease during exercise testing.

Coronary Disease↗
PubMed1992

Venous myogenic tone: studies in human and canine vessels.

Active and passive mechanical properties of human saphenous and canine femoral and saphenous vein segments were measured in vitro to assess the degree of pressure-dependent venous myogenic tone (% change in diameter, physiological saline solution vs. Ca(2+)-free solution) in these vessels. Stepwise elevation of intraluminal pressure from 2 to 20 mmHg caused an active myogenic response, which was calcium dependent. Side branches of human saphenous veins (OD at 20 mmHg: 1.92 +/- 0.15 mm control; 2.41 +/- 0.18 mm relaxed) displayed a larger degree of myogenic tone (approximately 25%) compared with dog saphenous (OD: 2.84 +/- 0.16 mm control; 2.89 +/- 0.16 mm relaxed) and femoral (OD: 3.56 +/- 0.32 control; 3.66 +/- 0.31 mm relaxed) veins (2-3%). This alteration in myogenic tone results in over 120% change in lumen capacity for the human saphenous vein, whereas for the dog saphenous and femoral veins, the change in lumen capacity is less than 10%. The vessels showed a constriction to norepinephrine as well as a reversible dilation to Ca(2+)-free perfusion. These results support the hypothesis that an active myogenic response may play an important role in the regulation of vascular capacity in the human saphenous vein, which is subject to substantial pressure variations due to changing orthostatic loads.

Animals↗
PubMed1991

[Diagnosis of coronary stenosis by clinical data and computer-assisted analysis of stress test].

A probability algorithm (PA) was developed and tested using the clinical, exercise test and coronary arteriography (CA) data of 543 patients (pts) studied with the suspicion of coronary artery disease (CAD). The algorithm was constructed from the data of 361 consecutive pts and tested on a separate group of 182 pts. The two pts groups were comparable in all respect. The sensitivity of Pain the diagnosis of CAD was higher compared to the exercise test alone (73% versus 68%, p less than 0.05). The numbers of variables used for the PA didn't influence of the sensitivity. The authors suggest to use the probability algorithms in the clinical practice.

Algorithms↗
PubMed1991

Preoperative silent myocardial ischemia. Has it prognostic significance?

We studied the prognostic significance of preoperative silent myocardial ischemia in patients undergoing coronary artery bypass grafting (CABG). Nonfatal and fatal perioperative myocardial infarction were regarded as prognostically important endpoints. Ninety-five patients (9 women) with stable-effort angina pectoris were studied during their hospital stay in the surgery ward before CABG. Silent ischemia was detected using Holter monitoring; all patients had Holter monitoring 76 +/- 9 h before surgery using Marguette Laser Holter and Cardiodata Prodigy systems. Two-channel electrocardiographic recordings were used which included CM5 and a modified inferior lead. Effort was taken to avoid leads with pathological Q waves and resting ST segment abnormalities. The mean duration of the monitoring was 27.9 +/- 11.3 h. Three patients (3.2%) had angina pectoris during these observations, 1 of them with significant ST depression. Silent ST depression was found in 12 patients (12.6%). Twelve patients (12.6%) had perioperative myocardial infarction. Perioperative myocardial infarction was more common in patients with silent ischemia: 4/12 vs. 8/83; chi 2 = 4.48955, p = 0.0341. Our results suggest that Holter monitoring identifies a group of patients with a higher probability of perioperative myocardial infarction. In the future, it may be possible to study different methods to prevent this surgical complication.

Adult↗
PubMed1989

[Ergometry-induced silent ischemia--clinical and angiographic features].

This study was planned to clarify the clinical and angiographic attributes of patients with exercise induced silent myocardial ischaemia. The study sample consisted of 102 patients who had ischaemic exercise electrograms (greater than = 1 mm ST segment depression) and significant angiographic stenosis (greater than = 50% diameter stenosis), in at least one of the major coronary arteries. In 61 patients (60%) painful ischaemia was observed during exercise (group A) while in 41 patients (40%) only SD depression (silent ischaemia) occurred (group B). The groups were similar with respect to age, sex, history of diabetes and all angiographic parameters including the Gensini coronary score. A history of prior myocardial infarctions was observed more frequently (p less than 0.01) in patients with silent ischaemia (group B). Prior myocardial infarction may be a factor causing silent myocardial ischaemia.

Aged↗
PubMed1989

[Symptomless (silent) myocardial ischemia and its prognostic significance].

The authors studied the prognostic significance of Silent myocardial ischemia. To study the correlation between the silent ischemia before the operation of coronary revascularization and the perioperative complications (infarction, mortality) Holter-monitoring (HM) was performed with 26 patients. The average time of HM was 43 +/- 3.1 h. During the observation period total 138 silent ischemic episodes were registered with 7 patients. The average heart rate observed during the ischemic event did not differ from that observed in other periods. Three myocardial infarctions occurred in the perioperative period one of them was of lethal outcome. Silent ischemia was detected in 2 of 3 patients before operation. The patient who displayed the gravest ischemic alteration died of perioperative myocardial infarction. On the basis of their observations the authors attribute prognostic significance to the preoperative silent myocardial ischemia.

Coronary Disease↗
PubMed1989

Experimentally induced acute changes in veins studied by scanning microscopy.

Endothelial damage caused by hypoxia and the local administration of Varicocid, or by using vascular clamps on the jugular vein of rabbits, was studied under a scanning electron microscope. Adhering platelets and fibrin were found only in the acutely damaged veins with endothelial defects. Swelling and vacuolization of endothelial cells did not induce intravascular coagulation. Adhering thrombocyte aggregates and fibrin strands can be found on the venous wall after acute changes under a scanning microscope only if part or all of the endothelial lining has been lost. Intravascular coagulation is not induced by swelling or vacuolization. The jugular vein of rabbits was studied after hypoxia, the administration of Varicocid and the use of vascular clamps.

Animals↗
PubMed1988

Comparison of histochemical and biochemical methods in the evaluation of estrogen and progesterone receptor level in human breast cancer. A study of 118 cases.

Unselected surgical specimens from 118 cancerous breasts of female patients were studied by histochemistry for the presence of cellular estrogen (ER) and progesterone (PR) receptors. The receptor tracers used were 17 beta-estradiol-6-carboxymethyl-oxim-bovine serum albumin - fluorescein isothiocyanate and 11 alpha-hydroxyprogesterone-hemisuccinate-bovine serum albumin-tetramethylrodamine isothiocyanate conjugate (Fluoro-CepTM). Out of 118 carcinomas 77 (67%) proved to be positive in the ER and 79 (66%) in the PR test. The histochemical results were compared with the results of the biochemical assay in 70 cases. A positive correlation was found in 57 cases.

Breast Neoplasms↗
PubMed1988

Painful and silent myocardial ischaemia during exercise testing.

The study was designed to clarify the clinical and angiographic attributes of patients with exercise induced silent myocardial ischaemia. The sample consisted of 102 patients who had ischaemic exercise electrograms (greater than or equal to 1 mm ST segment depression) and had a significant angiographic stenosis (greater than 50% diameter stenosis), in at least one of the major coronary arteries. In 61 patients (60%) painful ischaemia was observed during exercise (group A) while in 41 patients (40%) only ST depression (silent ischaemia) occurred (group B). The groups were similar with respect to age, sex, history of diabetes and all angiographic parameters including the Gensini coronary score. A history of prior myocardial infarctions was observed more frequently (p less than 0.01) in patients with silent ischaemia (group B). Prior myocardial infarction may be a factor causing silent myocardial ischaemia.

Adult↗