Biomedical subjects
M Benn
Publications and source records attributed to M Benn.
Sensory capacity of the royal college of surgeons rat.
PURPOSE: To apply noninvasive tests for examining visual and other sensory functions of pigmented Royal College of Surgeons (RCS) rats compared with pigmented and albino control animals. METHODS: Rats aged 3 and 7 months were tested with a general neurologic examination that assessed visual, auditory, tactile, and whisker displacement responses. Photophobic responses and visual discrimination were also measured. RESULTS: Dystrophic RCS rats failed the visual presentation tests, even at 3 months of age, and showed diminished performance on tactile tests. Auditory and whisker displacement performances were normal. Albino rats also showed diminished performance on the visual test, particularly to stimuli presented in the upper visual field. Photophobic responses were diminished in the dystrophic RCS rats compared with the pigmented control animals. Albino animals showed heightened photophobia. The dystrophic rats failed to reach criterion levels of performance on the visual discrimination test even with gratings of 0.045 cyc/deg. CONCLUSIONS: The tests used discriminate deteriorated complex visual functions in RCS rats at ages when some simple reflexes can still be demonstrated. As such, they provide easily executed tests for screening for the effects of reparative treatments such as transplantation, administration of growth factors, and gene transfer technology. The integrity of whisker and auditory function are important when using tests requiring polysensory inputs. The somatosensory defect is surprising but may be useful in searching for the gene locus of the retinal disorder. The aberrations seen in the albino rats may be attributable to the effects of light damage and unfiltered light.
QT dispersion in patients with arrhythmogenic right ventricular dysplasia.
AIMS: Arrhythmogenic right ventricular dysplasia is a rarely diagnosed cardiomyopathy, but a frequent cause of ventricular arrhythmia and sudden cardiac death. QT interval dispersion, measured as an interlead variability of QT, is a marker of dispersion of ventricular repolarization and, hence, of electrical instability. The present study was conducted to assess the occurrence of QT dispersion and its modulation during treatment with sotalol. Methods Twenty-five patients with the diagnosis of arrhythmogenic right ventricular dysplasia were studied retrospectively. Fourteen patients were considered low risk for malignant ventricular arrhythmia and sudden cardiac death, and 11 high risk due to documented sustained ventricular arrhythmia, cardiac arrest, or sudden cardiac death. Twenty five healthy volunteers served as control subjects. RESULTS: Dispersion of repolarization was significantly higher in patients than in control subjects (QTd and JTd: P<0.05). Dispersion of repolarization was equal in patients both with and without malignant arrhythmias. There was no significant change in dispersion after treatment with sotalol. Adjacent QT dispersion between leads V3-V4, V4-V5 and V5-V6, respectively, was higher in patients than in control subjects (P<0. 05), while no differences were seen in leads V1-V2 and V2-V3. CONCLUSION: QT interval dispersion is increased in patients with arrhythmogenic right ventricular dysplasia. However, the degree of dispersion is not related to the severity of symptoms, nor is it influenced by treatment with sotalol.
[Hereditary long QT syndrome].
The Long QT Syndrome (LQTS) is a hereditary disease, characterized by a prolonged QT-interval on the electrocardiogram and a high risk of syncope and sudden death due to ventricular arrhythmias. LQTS must be suspected in apparently healthy children and young people with syncope after emotional or physical stress. Untreated symptomatic patients have a high mortality, which is markedly reduced by sympathetic block. The knowledge of the diagnostic criteria for the LQTS, a detailed history including a family history and an ECG-recording with measurement of the QT-interval in every patient with inexplicable syncope will advance the diagnosis of the LQTS and improve the survival of these patients after proper therapy. The current knowledge on the molecular genetics, epidemiology, mechanisms of arrhythmias and therapy are presented with special emphasis on the defects in the control of ionic transport over the cell membrane caused by mutations in ion channels.
[Arrhythmogenic right ventricular cardiomyopathy].
Arrhythmogenic right ventricular dysplasia is a rare cardiomyopathy, but a frequent cause of ventricular tachyarrhythmia and sudden cardiac death among young otherwise healthy individuals. This article contains a review of the current knowledge on epidemiology, diagnosis, symptoms and signs as well as theories on etiology and pathogenesis, prognosis and treatment. The aim is to draw attention to the disease as a cause of syncope, ventricular tachycardia and sudden cardiac death.
Benign duodenocolic fistula. A case presenting with acidosis.
A case of benign duodenocolic fistula as a complication to peptic ulcer disease is presented, the case being interesting for the rarity of the diagnosis and by being complicated with acidosis. The etiology, clinical features, diagnosis, and treatment are reviewed.
Infective endocarditis, 1984 through 1993: a clinical and microbiological survey.
OBJECTIVES: To characterize the epidemiology and the clinical and microbiological spectrum of infective endocarditis in a Danish population. DESIGN: A retrospective review. SETTING: All episodes hospitalized of infective endocarditis from 1984 to 1993 in Viborg County were reviewed. The county is served by one general and four local hospitals. SUBJECTS: One hundred and nine episodes of suspected infective endocarditis with 62 episodes in 59 patients fulfilling the diagnostic criteria by von Reyn. RESULTS: An overall incidence of 27 episodes per million per year was found. The incidence was 17.4 episodes per million per year in the first part of the decade and 36.5 episodes per million per year in the second part (P < 0.001). Microscopic haematuria was found in 70.2% of the patients with infective endocarditis, compared to 16.7% of the patients in whom the diagnosis was rejected (P < 0.01). Staphylococcus aureus was found in 38.9%, non-beta-haemolytic streptococci in 24.1% and Enterococcus faecalis in 16.7%. The overall mortality was 35.5%. The mortality decreased significantly from 50.0% in the first part of the decade to 28.6% in the second part (P < 0.01). The mortality was 23.1% in patients in whom the diagnosis was established whilst they were alive. This finding was significantly lower than the overall mortality (P < 0.05). CONCLUSION: The incidence of infective endocarditis increased during the decade. The frequency of non-beta-haemolytic streptococci was lower than normally reported. Mortality is still high, with the main mortality within the first week in hospital, which stresses the importance of early case detection and treatment.
Prescribing oral contraceptives and the medical record.
Scripts for the oral contraceptive pill are written by general practitioners every day, but how organised are their prescribing habits? The author describes the use of a supplementary insert to medical records to aid the busy general practitioner.
The tired patient.
The management of the tired patient revolves primarily around a careful, detailed history, with specific emphasis placed on lifestyle factors and in particular ruling out a depressive illness. 'Time waits for no man' ... so say the sages--but it does wait for the GP in his or her evaluation of fatigue. Time is on our side. A careful follow up of the tired patient will aid in the future diagnosis of any evolving organic cause of the fatigue, and is also an integral part of the general management of the tired patient. These points are summarised in Table 2. So, remember, in the management of the tired patient 'mind your Ps and Qs'.
[Left ventricular diastolic function in heart failure--a Doppler echocardiography study].
Assessment of transmitral flow by Doppler echocardiography allows measurement of changes in left ventricular filling patterns in patients with cardiac disease. Typically a decrease in early diastolic flow velocity and increase in late diastolic flow velocity is found in various cardiac diseases. In order to assess the influence of overt heart failure on transmitral velocity profiles these were measured in 20 patients with a history of myocardial infarction and in 10 normal controls (group I). Of those patients with coronary heart disease 10 patients were in overt heart failure according to clinical and radiological criteria (group II); another 10 patients were compensated after treatment for heart failure (group III). In decompensated group II early diastolic flow velocity (E) was 91.2 cm/s and higher than 67.9 cm/s in group III (p less than 0.05) compared to 68.8 cm/s in the control group. In contrast late diastolic flow (A) at the time of atrial contraction was 41.2 cm/s in group II, 81.3 cm/s in group III, and 65.0 cm/s in group I (p less than 0.05). The ratio between early and late diastolic flow velocities (E/A) was 2.58 in group II, 0.87 in group III, and 1.06 in group I (p less than 0.05). Deceleration halftime was significantly shorter in group II as compared to the other two groups (p less than 0.05). These results can be interpreted as masking of the pathological flow patterns of the underlying heart disease (E/A ratio) by elevated left atrial filling pressure that leads to inversion of the pathologically altered velocity profiles of the underlying heart disease. These results might gain practical value for the care of patients in congestive heart failure if follow-up studies should demonstrate conversion of the flow pattern of group II to that of group III under treatment.
[Maximum rate of left ventricular volume change--a parameter of ventricular function (author's transl)].
Peak left ventricular ejection rate (dV/dtsyst) and peak left ventricular filling rate (dV/dtdiast) were determined from biplane cineangiographies in patients with normal left ventricular function (n = 8), pressure overload (n = 11), aortic regurgitation (n = 7), mitral regurgitation (n = 9), mitral stenosis (n = 6), hypertrophic obstructive cardiomyopathy (n = 10), congestive cardiomyopathy (n = 9) and coronary heart disease (n = 17). dV/dtsyst (normal 642 +/- 187 ml s-1) was reduced in mitral stenosis (447 +/- 77 ml s-1) and was increased significantly in aortic regurgitation (1085 +/- 162 ml s-1) and mitral regurgitation (744 +/- 232 ml s-1). dV/dtsyst/EDV was correlated linearly with ejection fraction and was reduced significantly in mitral stenosis, aortic and mitral regurgitation, congestive cardiomyopathy and coronary heart disease. Ventricles with pressure overload and coronary heart disease could be separated better from normal ventricles by dV/dstsyst/EDV than by ejection fraction. dV/dtdiast (normal 549 +/- 205 ml s-1) was decreased significantly in mitral stenosis and increased in aortic regurgitation (1141 +/- 557 ml s-1) and mitral regurgitation (946 +/- 349 ml s-1). Peak left ventricular filling rate and diastolic stiffness were correlated by a hyperbolic function. The results show that peak left ventricular ejection and filling rates allow a more detailed analysis of ventricular function than the usually applied parameters. Quantification of the factors which determine the rate of change of left ventricular volume was only partially possible.
[Ventricular and myocardial function in aortic regurgitation (author's transl)].
The influence of chronic volume load on ventricular function and myocardial load and shortening was investigated in 10 patients with chronic aortic regurgitation by means of biplane ventriculography and simultaneous pressure measurements. The regurgitant fraction was 63 +/- 15 per cent. Enddiastolic volume (EDVI 227 +/- 37 ml/m2), systolic (161 +/- 18 mm Hg) and enddiastolic ventricular pressure (30 +/- 12 mm Hg) were elevated, ejection fraction was reduced (54 +/- 7 per cent). Myocardial mass related to EDV was normal (1.2 +/- 0.2 g/ml). Contractility as measured from dp/dt max (1736 +/- 492 mm Hg s-1) and dp/dtmax/PI (22.2 +/- 4.3 s-1) was slightly reduced. Mean velocity of equatorial midwall fiber shortening VMW 0.45 +/- 0.13 cir X s-1) was significantly diminished, equatorial midwall fiber stress during ejection (sigma tej 267 +/- 44.5 X 10(3) dyn X cm-2) was elevated. In spite of a very high enddiastolic stress (sigma ED 96 +/- 36 X 10(3) dyn X cm-2) mean systolic power (sigma tej X VMX 123 +/- 43.2 X 10(3) dyn X cm-2 X s-1) was normal. Compensation of chronic volume load in aortic regurgitation is not compensated by an increased contractility but by ventricular enlargement and a pronouned increase in preload. Myocardial load and shortening in chronic aortic regurgitation are altered in the same way (increased stress and reduced shortening) as in chronic pressure overload.
[The influence of afterload on the normal and ischemic myocardium in the dog].
The influence of an instantaneous increase in afterload on the hemodynamics and regional myocardial function was studied in five anesthetized dogs before and after occlusion of the left anterior descending coronary artery. By inflation of an intaaortic balloon during single ejections, an instantaneous increase in afterload was obtained. From biplane cineventriculograms, the following parameters were calculated: left ventricular volumes (EDV, ESV), stroke volume (SV), ejection fraction (EF). Mean circumferential fiber shortening (V CF) was calculated in three ventricular diameters in the RAO projection. Simultaneously PLV, PLVED, PAo, and LV dp/dt were obtained. In the control ventriculograms, an increased afterload (delta PLV 16.4 +/- 8 mm Hg) caused only a minor decrease of SV (2.6 +/- 2.5 ml), EF (4.2 +/- 2.4%), and V CF (0.20 circ . s -1). After coronary occlusion (delta PLV 14.5 +/- 6.7 mm Hg),the reduction of SV (5.9 +/- 2.7 ml) and EF (8.2 +/- 2.6%) was more pronounced. This was caused mainly by a significant reduction of V CF in the center of ischemia (delta V CF -93%). For the evaluation of regional myocardial function by ventriculography, the marked influence of afterload in ischemic areas must be taken into consideration. This is of special interest in comparative ventriculograms, such as those before and after coronary bypass surgery.
[Systolic and diastolic ventricular and myocardial function in the volume stressed heart].
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[Systolic and diastolic ventricular and myocardial function in congestive cardiomyopathy (author's transl)].
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[The effect of contrast medium injection into the left ventricle on systolic and diastolic ventricle function].
The influence of contrast medium on systolic and diastolic left ventricular function was studied in eight patients with coronary heart disease and in five dogs during and five minutes after ventriculography. Two biplane ventriculograms were performed in 5-minute intervals, in the dogs an additional one after 10 minutes. 0.66 cc/kg BW of sodium methyl-glucamin-iothalamate were injected during diastole into the left ventricel. 1. During ventriculography there are only slight changes of left ventricular volumes, pressures and diastolic compliance. The first four opacified heart cycles can be evaluated for the analysis of left ventricular function. 2. In patients with coronary heart disease there are much more pronounced alterations of systolic ventricular function 5 minutes after Ventriculography than in the normal dog. The ischemic ventricle has a reduced tolerance for volume load and negative inotropic effect of contrast media. In patients and dogs diastolic compliance is significantly increased 5 minutes after the injection of contrast medium. After 10 minutes however in the dogs compliance is significantly decreased. Analysing left ventricular function by repeated ventriculographies one has to take into account that the function is altered by the first angiogram. The degree of the changes depends on the initial hemodynamic conditions and on the time interval between the ventriculograms.
[Proceedings: The effect of after-stress on the normal and ischemic dog myocardium].
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[Changes in the geometry of the left ventricle in healthy subjects and coronary patients during isovolumetric relaxation].
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