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Biomedical subjects

B Kunkel

Publications and source records attributed to B Kunkel.

At least 55 records · Page 3Linked to original sources
PubMed1986

Second symbiotic megaplasmid in Rhizobium meliloti carrying exopolysaccharide and thiamine synthesis genes.

Using physical and genetic data, we have demonstrated that Rhizobium meliloti SU47 has a symbiotic megaplasmid, pRmeSU47b, in addition to the previously described nod-nif megaplasmid pRmeSU47a. This plasmid includes four loci involved in exopolysaccharide (exo) synthesis as well as two loci involved in thiamine biosynthesis. Mutations at the exo loci have previously been shown to result in the formation of nodules which lack infection threads (Inf-) and fail to fix nitrogen (Fix-). Thus, both megaplasmids contain genes involved in the formation of nitrogen-fixing root nodules. Mutations at two other exo loci were not located on either megaplasmid. To mobilize the megaplasmids, the oriT of plasmid RK2 was inserted into them. On alfalfa, Agrobacterium tumefaciens strains containing pRmeSU47a induced marked root hair curling with no infection threads and Fix- nodules, as reported by others. This plant phenotype was not observed to change with A. tumefaciens strains containing both pRmeSU47a and pRmeSU47b megaplasmids, and strains containing pRmeSU47b alone failed to curl root hairs or form nodules.

DNA Transposable Elements↗
PubMed1985

Combined first-pass and equilibrium radionuclide ventriculography and comparison with left ventricular/right ventricular stroke count ratio in mitral and aortic regurgitation.

Effective and total left ventricular (LV) stroke volume were assessed in 31 patients with verified aortic or mitral regurgitation, or both, and in 22 patients with normal valvular function using combined first-pass and equilibrium radionuclide ventriculography. The difference between these 2 volumes as a fraction of LV stroke volume was taken as the radionuclide regurgitant fraction. The results were compared with the LV/right ventricular (RV) stroke count ratio and with the angiographic regurgitant fraction according to the method of Sandler and Dodge. Radionuclide regurgitant fraction derived from 2 determinations with a time interval of 1 week showed good reproducibility (n = 15, r = 0.96, SEE = 9.1). Sensitivity was 100% for radionuclide regurgitant fraction and 87% for LV/RV stroke count ratio at equal specificity (100%). Radionuclide regurgitant fraction was more sensitive, especially in severely ill patients, in whom additional RV volume overload led to false-low or false-negative ratios. Angiographic and radionuclide regurgitant fraction showed linear correlation (r = 0.79, p less than 0.001). In contrast, because 5 patients had RV volume overload, only a weak correlation could be noticed between angiography and LV/RV stroke count ratio (r = 0.47, p less than 0.05). Excluding these patients, correlation substantially improved (r = 0.74, p less than 0.001). The combination of first-pass and equilibrium radionuclide ventriculography is a sensitive, specific and well reproducible method for the evaluation of mitral and aortic regurgitation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

[2 families with dilatative cardiomyopathy].

In two brothers each of two families congestive cardiomyopathy was diagnosed. Left ventricular biopsy showed individually differing degrees of hypertrophy of the myocardial cells together with endocardial fibrosis and circumscribed interstitial fibrosis. In family I clinical symptoms appeared at the beginning of the 4th decade, conduction disturbances being predominant. One brother died after rapid progression of the disease within one year. The other has been treated as an outpatient for 9 years; he received a pacemaker implant half a year ago. In family II initial symptoms appeared in the middle of the 6th decade, progressive heart dilation and insufficiency being the predominant characteristics. In the course of 7 years one brother has developed cardiac decompensation whereas the other brother's condition has remained nearly unchanged for 4 years. The degree of myocardial changes in left ventricular biopsies correlated with the clinical course.

Adult↗
PubMed1985

[Transluminal coronary angioplasty 1977-1985. Experience with 1000 interventions].

Transluminal coronary angioplasty (TCA) was introduced in 1977 for dilatation of coronary stenoses. From October 1977 to December 1984 1087 procedures have been performed in Frankfurt. The mean success rate was 77% with an increase from 58% to 84% since 1977. Recurrences were seen within the first year in 15% of the patients, which could be treated successfully in a high percentage with a second TCA. Emergency bypass operations were necessary in 5.2%. Four patients (fatality rate 0.37%) died as consequence of the intervention. Within few years TCA has become an established procedure for myocardial revascularisation, with a high success rate. Major progress has been possible in the last few years due to technical developments, which are still going on. They may lead to further improvement of the results and enlargement of the indication for TCA.

Adult↗
PubMed1985

[Coronary perfusion in acute vascular occlusion within the scope of transluminal coronary angioplasty].

The procedure of coronary perfusion during transluminal coronary angioplasty (TCA) is described. By using guide wires of a length of 300 cm it is possible to exchange a balloon catheter for a perfusion catheter in acute vascular occlusion. Arterial blood is withdrawn and correspondingly supplied distal to the occlusion to meet the myocardial need for sufficiently oxygenated blood. Ischemia resolves, resulting in the normalization of left ventricular function and resolution of subjective complaints. This procedure can maintain myocardial oxygen supply until emergency coronary bypass graft surgery or repeat angioplasty. It might help to reduce mortality secondary to transluminal coronary angioplasty.

Angioplasty, Balloon↗
PubMed1985

[Biopsy and autopsy frequency of myocarditis].

Mononuclear infiltrations indicative for myocarditis were found in 3 out of 171 left ventricular biopsies from patients with cardiomyopathies (1.2%). One patient had a normal EF, one had a minimally and one a markedly reduced ventricular function. Among 5,804 consecutive necropsies myocarditis was diagnosed in 308 cases (5.3%). 1.3% were septic in origin while mononuclear infiltrations were found in 3.7% and special morphology in 0.3%. Combined detailed analysis both of clinical and autopsy data could be performed in 84 patients who had died in our own hospital. 82 patients had severe additional diseases determining clinical symptoms and course. Myocarditis without other underlying diseases was found in 2 patients only. Infiltrations were widespread and diffuse in both ventricles and atria in these cases. Myocardial inflammation could not be diagnosed from clinical parameters (X-ray, symptoms, ECG) in any case. Our bioptical data demonstrate that myocarditis does not play a major role in the pathogenesis of dilated cardiomyopathies. Diffuse myocarditis of clinical relevance rarely occurs in adults while focal myocardial infiltrations can be found in a majority of diseases. Reliable clinical symptoms indicative for inflammatory myocardial disease could be found neither in cases with concomitant nor in patients with diffuse myocarditis.

Biopsy↗
PubMed1985

[Follow-up studies in chronic aortic insufficiency].

In order to study the course of chronic aortic regurgitation 17 patients with various degrees of aortic valve incompetence were investigated twice with a time interval of 1.5 +/- 0.4 years. The following parameters were evaluated: NYHA class; electrocardiographic sum of the largest R-wave in V4-V6 plus the largest S-wave in V1-V3 (RS index); echocardiographic left ventricular end-diastolic diameter (EDD); roentgenographic heart volume (HV); scintigraphic left ventricular end-diastolic volume (EDV), regurgitated blood volume (RBV) and ejection fraction (EF). During the period of observation functional deterioration occurred in 5 cases, all suffering from moderate to severe aortic regurgitation. While EF did not change significantly (55 +/- 12% vs. 55 +/- 11%), all other parameters showed a significant increase: RS index 5.4 +/- 1.4 mVolt to 6.0 +/- 1.7 mVolt (p less than 0.01); EDD 6.3 +/- 0.7 to 6.8 +/- 0.9 cm (p less than 0.001); HV 1017 +/- 151 ml to 1099 +/- 261 ml (p less than 0.01); EDV 371 +/- 131 ml to 441 +/- 175 ml (p less than 0.001); RBV 117 +/- 57 ml to 151 +/- 77 ml (p less than 0.001). Cases with functional deterioration showed a higher initial EDV and EDD (487 +/- 143 vs. 322 +/- 93 ml, p less than 0.05; 7.1 +/- 0.7 vs. 6.1 +/- 0.5 cm, p less than 0.01). The increase of HV, EDV and RBV during the time of observation was higher than in the remaining patients (166 +/- 137 vs. 39 +/- 95 ml, p less than 0.05; 133 +/- 75 vs. 44 +/- 29 ml, p less than 0.01; 66 +/- 22 vs. 22 +/- 31 ml, p less than 0.01). On average it was less pronounced in cases with mild initial left ventricular dilation than in those with marked dilation.(ABSTRACT TRUNCATED AT 250 WORDS)

Angina Pectoris↗
PubMed1984

Volumetric evaluation of aortic regurgitation by combined first-pass/equilibrium radionuclide ventriculography.

In 16 men with normal valvular function (group 1) and 23 men and one woman with isolated aortic regurgitation (group 2) effective stroke was determined by first-pass radionuclide ventriculography. Total left ventricular stroke volume was derived from equilibrium radionuclide ventriculography using a geometric approach for the end-diastolic volume multiplied by the ejection fraction. The difference between the two stroke volumes as a fraction of total left ventricular stroke volume was taken as radionuclide regurgitant fraction. Radionuclide lv/rv stroke count ratio was calculated as the ratio of end-diastolic-end-systolic count-rate differences from the left and right ventricles. All patients underwent left heart catheterization. Angiographic regurgitant fraction was evaluated by the method of Sandler and Dodge in 16 patients of group 2. In the others, aortic regurgitation was quantified in 5 grades of severity. Group l was classified correctly by both radionuclide regurgitant fraction and lv/rv stroke count ratio (specificity 100%). In group 2 the radionuclide regurgitant fraction was elevated in all (from + 20% to +88%, sensitivity 100%), radionuclide lv/rv stroke count ratio in 19 of 24 cases (from 0.6 to 5.6, sensitivity 79%). The angiographic regurgitant fraction correlated well with the radionuclide regurgitant fraction (r = 0.78), whereas no significant correlation was found between the angiographic stroke volume ratio (i.e. left ventricular stroke volume/cardiac output per beat) and radionuclide stroke count ratio (r = 0.10) due to the high rate of false-negative results of the latter method.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1984

[Reversibility of akinetic segments in coronary heart disease].

Akinetic wall segments not exhibiting contractions following nitroglycerin administration or in a post-extrasystolic beat are usually considered to consist of scar tissue; i.e. even by re-established or improved blood supply following aorto-coronary bypass surgery no functional improvement is expected. In the present study, the pre- and postoperative ventriculograms (RAO projection) of 24 patients undergoing bypass surgery were analyzed. Ventriculography was routinely performed following sublingual nitroglycerin and a post-extrasystolic contraction. In each patient the akinetic segment had received a bypass graft which was found to be patent on reangiography. In 7 of 24 patients (29%) the formerly akinetic segment exhibited improved contraction postoperatively; in 17 patients the segment remained akinetic. Global ejection fraction rose in the group of patients with improved akinesia from 47 +/- 10 to 65 +/- 10% (p less than 0.05). In the patients with unchanged contraction pattern, ejection fraction was found to be 56 +/- 12% prior to surgery and 54 +/- 16% after surgery (n.s.). The increase in ejection fraction was more pronounced in those patients showing improvement of anterior wall akinesia (from 39 to 72%) than it was in patients exhibiting improved inferior wall akinesis (from 54 to 59%). According to these findings, the regional ejection fraction was found to be higher postoperatively in patients with former anterior wall akinesis (78%) than in those showing inferior wall contraction abnormalities (49%). End-diastolic and end-systolic left ventricular volume changes postoperatively did not reach statistical significance, although end-systolic volume showed a clear trend to decrease (preoperative: 114 +/- 54 ml/1.73 m2; postoperative: 79 +/- 29 ml/1.73 m2; n.s.).(ABSTRACT TRUNCATED AT 250 WORDS)

Angina Pectoris↗
PubMed1984

[Hemodynamic and echocardiographic long-term results of closed mitral commissurotomy].

During recent years open mitral commissurotomy (OMC) has seemed to be more favorable than closed commissurotomy (CMC). Up to now only few long-term results including hemodynamic data of mitral valve reconstruction have been reported. 69 of the 103 patients who underwent CMC between 1973 and 1980 were followed over a mean period of 5.3 +/- 2.1 years after intervention. 5 patients died. In 8 (11%) a prosthetic valve replacement was necessary (restenosis 4, insufficiency 2, combined valve disease 2). 36 of the patients were clinically improved (at least 1 NYHA class), 21 (30%) maintained the same NYHA class, and 7 (10%) had deteriorated. The relative heart volume (HV) from supine chest X-rays decreased from 1010 ml/1.71 m2 to 906 ml/1.73 m2 (n = 42, p less than 0.01). The mitral valve area ( MOFL ; n = 25) increased from 1.2 cm2 (Gorlin formula) to 2.6 cm2 (2D-echo) (p less than 0.001). Mean pulmonary artery pressure ( MPAP ) at rest decreased by 29% (from 33.6 mm Hg to 23.8 mm Hg, n = 37, p less than 0.001) and during exercise by 36% (from 69.5 mm Hg to 44.8 mm Hg, n = 10, p less than 0.01). The reduction in PA pressures and the increase in mitral valve area did not correlate and showed no relationship to the intraoperatively estimated success of commissurotomy. Our findings reflect very satisfactory long-term results after closed commissurotomy, which are comparable with those of open valvotomy.

Adolescent↗
PubMed1982

[Combined first-pass-/equilibrium radionuclide ventriculography for non-invasive evaluation of aortic valve incompetence].

In 15 patients with pure aortic valve incompetence and 5 patients with normal valvular function we determined cardiac output by first-pass-radionuclide ventriculography. In addition, left ventricular stroke volume was evaluated by equilibrium radionuclide ventriculography. The difference between those two volumes in relation to left ventricular stroke volume is the regurgitant fraction. Stroke volume index was calculated as the ratio of enddiastolic-endsystolic count differences of left and right ventricle. Patients with aortic insufficiency demonstrated a regurgitant fraction between 20 and 88%, whilst controls never exceeded 10% (on average-2%). Sensitivity therefore was 100%. In contrast, 2 of 15 patients with aortic valve incompetence showed a stroke volume index within normal range (sensitivity 87%). Regurgitant fraction correlated well with aortographically determined severity of valvular incompetence (r = 0.94). We conclude that combined first-pass-/equilibrium radionuclide ventriculography is a highly sensitive quantitative method for evaluation of aortic insufficiency.

Adult↗
PubMed1981

[Angiography of the orbit (author's transl)].

Advances in angiography of the orbit are presented. Angiography is done by selective catheterisation of the internal carotid artery or of the branches of the external carotid artery supplying the periorbital area. Since the procedure is done without heavy sedation or even general anesthesia, the patient can follow instructions and move his eyeballs or open or close his eyelids if wanted for the procedure. Magnification angiography and subsequent subtraction is necessary to obtain good images of the globe permitting visualisation of even the smallest vessels in the choroid layer.

Angiography↗
PubMed1981

[Selective angiography of the external carotid artery and branches (author's transl)].

Selective angiography of the external carotid artery and superselective angiography of single branches can be used for demonstration of blood supply of dural tumors, tumors of the skull, skull base and of facial parts of the skull. Especially malformations of vessels and their blood supply can be shown. Improvements in x-ray technique and apparatus enable movement angiography, which can be very helpful for the diagnosis of special changes. In special kinds of headache influences from outside to the external carotid artery, to the maxillary artery, to the ascending pharyngeal artery, to the posterior auricular artery, to the occipital artery and the meningeal branches can be of higher importance than was assumed before. Selective angiographies of the external carotid artery and radiographic investigations of the anatomical situation are giving the basis for planning of embolisations. For diagnosis of intra- and extra-cranial changes the neuroradiologist is the connecting person between all specialists for skull and brain.

Aged↗