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Biomedical subjects

P Gregor

Publications and source records attributed to P Gregor.

At least 91 records · Page 5Linked to original sources
PubMed1988

Myocardial contrast echocardiography: a new method for the evaluation of regional myocardial blood flow.

Myocardial contrast echocardiography is a new method enabling detailed evaluation of blood flow distribution within the myocardium. It is performed by means of intracoronary injection of small volumes of carrier solutions containing small microbubbles of a size similar to that of red blood cells. The perfused myocardium opacifies densely, while the ultrasonic backscatter of nonperfused areas does not change. This method enables evaluation of the physiologic impact of coronary stenosis, diagnosis of "small vessel disease", collateral blood flow assessment, infarct size measurement and, with the help of videomemory and a computer, also regional myocardial blood quantification. This paper reviews all hitherto published studies with myocardial contrast echocardiography in humans including some studies only recently submitted for publication. These studies examined a total of 169 patients. No complications of intracoronary injection of microbubbles were described. Transient ECG and haemodynamic changes of less than 30 seconds' duration are less pronounced than during routine coronary arteriography. This paper describes the methodology, safety, physiology and potential clinical usefulness of myocardial contrast echocardiography.

Contrast Media↗
PubMed1988

Clinical findings in hypertrophic cardiomyopathy and their relationship to the disease severity.

The clinical and electrocardiographic findings of 82 patients presenting with hypertrophic cardiomyopathy were compared with the distribution and extent of myocardial hypertrophy. The clinical and ECG signs did not depend on either the presence or the degree of the obstruction. Subjective complaints (with the exception of dypnoea) were not related to the value of myocardial thickness but they correlated with the square extent of the area affected by hypertrophy of the myocardium. It was distinct in the case of dyspnoea and especially syncope the occurrence of which was significantly higher in patients with a higher extent of hypertrophy. This extent of hypertrophy was reflected in our previously published classification of hypertrophic cardiomyopathies which is based on echocardiographic analyses of the individual parts of myocardial thickness.

Adolescent↗
PubMed1988

The picture of hypertrophic cardiomyopathy in the elderly.

The aim of the study was to analyse the findings obtained in 27 patients with hypertrophic cardiomyopathy who lived to be 60 and more. Elderly patients are, more frequently than younger ones, women, mostly with a negative family history (81% vs. 30% in younger patients), with a lower incidence of syncope (11% vs. 25%), smaller myocardial wall thickness and lesser extent of hypertrophy. Elderly patients displayed mitral ring calcification more often (18%) than younger subjects (6%) or those of the same age but free of hypertrophic cardiomyopathy (3%). Pathological Q waves on the ECG recording were likewise less frequent (7.6% vs. 20.4%). While elderly patients exhibited manifest proneness to elevated values of left ventricular end-diastolic pressure, there were no marked differences in obstruction.

Aged↗
PubMed1988

Myocardial contrast echocardiography. A review of clinical studies.

A review is presented of to date published studies devoted to contrast echocardiography of the myocardium and covering a total of 169 patients. No complications occurred during investigations; slight transient ECG and haemodynamic changes of less than 30 s duration were not as pronounced as during coronary arteriography. Intracoronary administration of a 3-4 ml solution containing microbubles close to erythrocyte size leads to opacification of the perfused part of the myocardium in echocardiographic image, whereas the echogenity of nonperfused parts remains unchanged. With the use of this method it might be possible to evaluate the significance of coronary stenosis, to diagnose the "disease of small arteries", to assess the collateral circulation, myocardial infarction size, and to quantify the blood flow in various parts of the myocardium in real time. The method is promising for the assessment of myocardial microcirculation as a complement of coronary arteriography.

Contrast Media↗
PubMed1988

Severe diffuse hypokinesis of the remote myocardium--the main cause of cardiogenic shock? An echocardiographic study of 75 patients with extremely large myocardial infarctions.

Two-dimensional echocardiography was performed in 75 patients with extensive myocardial infarctions to prove why cardiogenic shock develops only in a minority of such patients. 23 patients with clinical signs of shock formed group A, and 52 patients without signs of shock group B. The extent of akinesis and/or dyskinesis was the same in both groups. The "Asynergy Index"--involving also hypokinesis--was more favourable in group B (126 +/- 28, compared with 158 +/- 23 in group A, p less than 0.05). The ejection fraction was significantly higher in group B (33 +/- 12%, compared with 17 +/- 6% in group A, p less than 0.01). The cause of these differences was severe diffuse hypokinesis of the remote myocardium, which was present in all 23 patients with cardiogenic shock and only in 2 patients without shock (p less than 0.001). All 23 patients with shock had multi-vessel disease, which was present only in 19% of patients without shock (p less than 0.01). The study shows that in addition to two known conditions necessary for the development of cardiogenic shock (multi-vessel disease and infarct size at least 40% of the left ventricle), there exists a third condition of equal importance: severe diffuse hypokinesis of the remote myocardium.

Adult↗
PubMed1987

Regulation of sexual differentiation in D. melanogaster via alternative splicing of RNA from the transformer gene.

The transformer (tra) gene regulates female somatic sexual differentiation and has no known function in males. It gives rise to two sizes of RNA, one non-sex-specific and one female-specific. These two RNAs are shown to be present throughout the life cycle, and related by the use of alternative first intron splice acceptor sites. The non-sex-specific RNA has a 73 base first intron, while that in the female-specific RNA is 248 bases. The non-sex-specific RNA has no long open reading frame, while the female-specific RNA has a single long open reading frame beginning at the first AUG. Substitution of a heat shock promoter for the tra promoter still leads to female-specific differentiation of otherwise tra-females. We suggest a mechanism by which Sex-lethal controls itself and tra.

Animals↗
PubMed1987

Autoantibodies in hypertrophic cardiomyopathy and their clinical significance.

Data concerning autoantibodies in hypertrophic cardiomyopathy are rare and controversial and only the results of indirect immunofluorescence methods are available in the literature. The aim of this study was to determine the frequency and clinical significance of autoantibodies in hypertrophic cardiomyopathy by means of the Western blot which is a highly sensitive immunological technique. Sera from twelve (48.0%) of the whole group of 25 patients with hypertrophic cardiomyopathy reacted with actin from the HeLa extract. The incidence of anti-actin antibodies in sera from 23 ischaemic heart disease patients was 13.0% (P less than 0.025) and in 37 apparently healthy subjects was 8.1% (P less than 0.001). When samples were assayed on the actomyosin prepared from Xenopus laevis muscle, sera of 14 (56.0%) of the patients exhibited actin positivity while the positivity in ischaemic heart disease and in healthy subjects was found to be 13.0 and 13.5%, respectively (P less than 0.001). Presence of anti-actin antibodies was related to the functional and clinical status and the progression of the disease. Anti-actin antibodies were found more frequently in medically treated patients. These data suggest that anti-actin antibodies are probably not directly involved in the pathogenesis of hypertrophic cardiomyopathy, but their detection might be useful as an additional marker of disease severity.

Actins↗
PubMed1987

[Effect of intracoronary thrombolytic therapy on the development of the complications of myocardial infarction].

The incidence of myocardial infarction complications, detectable clinically or echocardiographically, was evaluated in 2 groups of patients: 62 patients treated with selective intracoronary thrombolysis (SIT) and 40 conventionally treated controls (C). Local femoral arterial lesions or hemorrhages developed in 16% of SIT patients, while intracardiac thrombosis was more frequent in the controls (35% versus 6% in the former; p less than 0.001). Left ventricular dyskinesias and heart failure were apparently less common in the SIT patients, however the differences were not significant. The comparison between patients with successful and stable recanalization and the controls showed significant differences, however; the incidence of left ventricular dyskinesias was 9% and 38% (p less than 0.005), respectively, the incidence of heart failure was 0% and 30% (p less than 0.001), and the incidence of intracardiac thrombosis was 3% and 35% (p less than 0.001). Differences in mortality rates were not significant between the two groups (0% for SIT versus 10% for controls).

Adult↗
PubMed1986

Cerebral methylations in epileptogenesis.

This chapter deals with the neurochemical consequences of the administration of the chemical convulsant agent L-methionine-dl-sulfoximine (MSO) on the brain of rodents. The principal notion is that this convulsant agent differs qualitatively from most quick-acting and predominantly lethal convulsant agents, commonly used in laboratory studies in epilepsy modeling because it has a preconvulsant latency period of several hours and also because it need not be fatal to the animals receiving it if they are properly managed during the preconvulsant period and following the first seizure attack. The historical profile of MSO as a useful and unique laboratory tool for neurochemical and molecular studies is briefly recounted, and the point is made that MSO is a close derivative of the amino acid L-methionine, which is used by each and every brain cell as a protein building block and as a precursor of the universal cellular methyl donor molecule, S-adenosyl-L-methionine. The importance of methylations, a set of reactions which consist in the transfer of the methyl group of S-adenosyl-L-methionine to several dozens of endogenous methyl acceptor molecules, small and large, is stressed and reviewed both historically and as this process relates to MSO epileptogenesis. The multiple effects of MSO on the methylation of small MW compounds, histamine being the working example, are reviewed. The involvement of phospholipid, nucleic acid, and protein methylations, all apparent targets of MSO action, in that they respond to the MSO challenge by a significant rate increase is elucidated. Finally, the effects of MSO at the functional level of brain receptor action are presented.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗