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Biomedical subjects

R Frank

Publications and source records attributed to R Frank.

At least 505 records · Page 28Linked to original sources
PubMed1982

Right ventricular dysplasia: a report of 24 adult cases.

Right ventricular dysplasia is characterized by an abnormality in the development of part of the right ventricular musculature. Patients with right ventricular dysplasia may present with ventricular tachycardia, supraventricular arrhythmias, right-heart failure or asymptomatic cardiomegaly. Twenty-two adult patients with right ventricular dysplasia who had recurrent ventricular tachycardia were seen during a 7-year period. The male/female ratio was 2.7:1. The mean age at the time of hospitalization was 39 years. All but one of the patients had ventricular tachycardia of a left bundle branch block configuration. With few exceptions, the T waves were inverted over the right precordial leads. The heart was usually enlarged and the pulmonary vasculature was usually normal. In six patients who had two-dimensional echocardiograms, all showed increased right ventricular diastolic dimensions. All patients had right ventricular angiography; the diagnosis of right ventricular dysplasia was substantiated during surgery in 12 patients and at autopsy in another. Two other patients who did not have arrhythmias had right ventricular dysplasia diagnosed by right- and left-heart angiography. Our unique experience, when combined with a literature review of 34 adult cases, permits a composite clinical profile of this condition in the adult.

Adolescent↗
PubMed1982

Measurements of respiratory ammonia and the chemical neutralization of inhaled sulfuric acid aerosol in anesthetized dogs.

The extent of neutralization of inhaled H2SO4 aerosol by endogenous NH3 has been measured in the surgically isolated upper airways of anesthetized dogs. Neutralization was observed to be inversely proportional to particle size. The H2SO4 particles with initial dry diameters of 0.5 micrometer and 1.0 micrometer underwent 0.28 (+/- 0.08) and 0.06 (+/- 0.06)% neutralization per ppb of laryngeal NH3, respectively, during passage through the mouth and out of the larynx at a flow of 0.1 L/s. At either particle size, neutralization is related to the route of entry, being greater for entry via the mouth than the nose. Limited measurements for entry via the mouth show more neutralization of 0.7 micrometer particles at 0.1 L/s than at 0.2 L/s. These results are consistent with a reaction that is limited by the rate of NH4 diffusion to the particle's surface.

Aerosols↗
PubMed1982

[Arrhythmogenic right ventricular dysplasia and Uhl's disease].

Ventricular tachycardia with left bundle branch block appearance in adults without coronary artery disease may be due to arrhythmogenic right ventricular dysplasia. This condition forms part of a spectrum with the complete form of Uhl's anomaly at one end and arrhythmogenic right ventricular dysplasia at the other. Both conditions have similar histological appearances representing the same congenital defect but the macroscopic appearances are quite different. Arrhythmogenic right ventricular dysplasia seems to be a slowly progressive condition with one or more localisations in the right ventricle where the myocardium is replaced by adipose tissue with progression of lesions from the epicardium towards the endocardium. The subepicardial layers resemble a plexiform structure of partially degenerated myocardial fibres within fibro-adipose tissue. These fibres may be the site of slowing of activation and the anatomical basis of intraventricular reentry phenomena. A similar appearance is also found in UHl's anomaly, but the severe dilatation of the ventricle and almost complete absence of muscle fibres only leaves a few zones with surviving, partially degenerated myocardial fibres. Clinically, a cardiothoracic index of over 0.60 is more common in Uhl's anomaly whilst arrhythmogenic right ventricular dysplasia is usually associated with a normal cardiac silhouette or only slight cardiomegaly. The differential diagnosis is important if surgery is being considered. An appropriate technique must be chosen to avoid supraventricular arrhythmias which can lethal in patients with Uhl's anomaly.

Adolescent↗
PubMed1982

[Difficulties of persistent repolarization following normalization of the QRS wave in the Wolff-Parkinson-White syndrome].

The normalisation of the ventricular complex in the Wolff-Parkinson-White syndrome is often accompanied by changes in the repolarisation phase with a deep, symmetric and pointed T wave suggestive of coronary artery disease. In order to study this phenomenon we examined 29 cases of intermittent WPW, 13 of which had abnormalities of the normalised complex. Normalisation occurred spontaneously on 10 occasions, twice on exercise and once after Ajmaline. In the majority of cases (9/13) the preexcitation was a right (4 cases) or left (5 cases) posterior pathway and the T waves were abnormal in the posterior leads (II, III and AVF). In left lateral preexcitation the T waves were negative in lead 1 and AVL. The T wave changes seem to be related to the topography of the preexcitation pathway. They gradually disappeared in the 3 cases in which preexcitation had not recurred. The age of the patients (11 to 45 years, average 31 years) or normal coronary angiography, performed in 3 cases, excluded coronary pathology as did the close relationship between the topography of the preexcitation and the T wave changes and the gradual disappearance of the abnormalities in the cases where preexcitation did not recur. This phenomenon, related to abnormal ventricular activation, seems to be comparable to the changes in ventricular repolarisation observed on termination of ventricular pacing, on the regression of certain intermittent left bundle branch blocks and perhaps, in some cases, of the post-ventricular tachycardia syndrome.

Adolescent↗
PubMed1982

[Encircling endocardial ventriculotomy in the treatment of recurrent ventricular tachycardia after myocardial infarction].

Thirty nine men and two women aged 26 to 76 years old (average 55 years) with ventricular tachycardia (VT) complicating chronic myocardial infarction were operated on between December 1971 and September 1980. Epicardial mapping was performed in sinus rhythm in 25 cases and in VT in 12 cases. The series was divided into two consecutive groups: --The first group comprised 14 patients operated on between December 1971 and November 1975 in which the operative mortality at the 30th day was 36%. There was one death due to recurrent VT in the early post-operative period; two deaths due to arrhythmia were observed between the 11th and 26th postoperative months. VT was successfully prevented in 6 cases with over 2 years' follow-up. --The second group comprised 27 patients operated after November 1975, in which encircling endocardial ventriculotomy (EEV) was the procedure used. The operative mortality fell to 18% with no relation to the arrhythmia. In the first 10 cases of this group, VT recurred in 2 patients in the early postoperative period. These two cases were controlled with antiarrhythmic therapy at doses that had been ineffective preoperatively. Four other recurrences of VT were observed at the 3rd, 34th, 45th, and 56th postoperative months. They were controlled by anti arrhythmic agents in 3 cases. The other patient died. VT was prevented for over 2 years in 7 patients and for over I year in 16 patients. These results suggest that EEV is more effective than the techniques used previously in resistant VT. Its side effects on myocardial contractility are discussed.

Adult↗
PubMed1982

Effects of triiodothyronine and propylthiouracil on plasma lipoproteins in male rats.

Hyperalphalipoproteinemia, characterized by increased plasma concentrations of apoA-I and of HDL lipid and protein, was observed in rats treated with triiodothyronine (T(3)) for 7 days. The increase in the plasma HDL apoproteins was general for apoC, apoE plus A-IV, and apoA-I, as determined by isoelectric focusing. Hypotriglyceridemia, characterized by decreased concentrations of VLDL and apoB, was also observed in the hyperthyroid state. Although in the mildly hypothyroid animals (propylthiouracil-treated), hepatic metabolism of free fatty acid is shifted toward esterification to triglyceride and VLDL formation, as we reported previously, plasma HDL and apoA-I concentrations were not different from control plasma values, while the d 1.006-1.063 g/ml (IDL + LDL) lipoprotein fraction tended to be increased. In general, the proportion of apoE in the (IDL + LDL) fraction of the hypothyroid rat was greater than in controls and hyperthyroid animals, while the proportion of apoE tended to be lower in VLDL from both hypo- and hyperthyroid rats than in VLDL from controls. An enhanced release of apoA-I by perfused livers isolated from rats treated with T(3) was also observed; this enhanced output of apoA-I may explain, in part, the hyperalphalipoproteinemia observed in these rats. The depressed net output of apoA-I in vitro by perfused livers from rats treated with propylthiouracil (PTU) was not expressed in a statistically significant diminished plasma concentration of HDL or apoA-I in the intact animals. Treatment with T(3) also resulted in modification of the content of essential fatty acids in various lipid classes. Linoleic acid residues were significantly reduced and arachidonic acid content was increased in plasma phospholipids and esterified cholesterol in T(3)-treated rats. However, the relative fatty acid composition of unesterified fatty acids and triglyceride fatty acids was not altered by T(3) treatment. PTU treatment had no effect on fatty acid distribution in any of the plasma lipids. Secretion of biliary lipids was increased in perfused livers from T(3)-treated rats, while treatment with PTU did not affect release of lipids in the bile. These observations suggest a regulatory role for thyroid hormones that determine concentration and composition of plasma HDL and other lipoproteins.-Wilcox, H. G., W. G. Keyes, T. A. Hale, R. Frank, D. W. Morgan, and M. Heimberg. Effects of triiodothyronine and propylthiouracil on plasma lipoproteins in male rats.

Animals↗
PubMed1981

Identification and suppression of secondary structures formed from deoxy-oligonucleotides during electrophoresis in denaturing polyacrylamide-gels.

Nature and stability of secondary structures formed from DNA-fragments during electrophoresis in urea containing polyacrylamide-gels were investigated. Duplices and especially hairpin loops were found to be surprisingly stable. Polyacrylamide-gels containing high concentrations of formamide effectively melt these structures. Such gels will improve nucleotide sequence analysis in regions of dyad symmetry that often cause 'band compressions' under standard electrophoresis conditions.

Electrophoresis, Polyacrylamide Gel↗
PubMed1981

[Automated analysis of electrocardiograms at rest: present status (author's transl)].

Computer interpretation of electrocardiograms was developed twenty years ago and is now routinely performed in the United States, where 9 different programs are being used. Depending on diagnosis and program, computer interpretation shows an 80-100% correlation with human interpretation. The systems provide an aid to diagnosis in preventive medicine and in hospitals without cardiologists, but since interpretations are standardized they are also useful in cardiology units, where they can be used to build up data banks, compare repeat ECGs with clinical findings and thus ultamately perfect electrocardiographic criteria. The use of this technique in Europe remains limited. In France, only two centers possess routine equipment. This feable diffusion is partly due to the cost of computer analysis, which can only compete with that of human interpretation if each system performs a sufficient number of ECGs.

Computers↗