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Biomedical subjects

G Frank

Publications and source records attributed to G Frank.

At least 163 records · Page 9Linked to original sources
PubMed1989

High concentrations of catecholamines in human hypothalamic-hypophysial blood.

While the hypothalamic-hypophysial portal system has been extensively studied in laboratory animals, equivalent studies have not been performed in humans. Here, we present an experimental procedure for collecting suprapituitary blood in man. To solve the question on the origin of such blood we investigated specific markers of hypothalamic secretory activity: the catecholamines (CAs). We found (a) norepinephrine (NE), dopamine (DA), and epinephrine (E) concentrations from approximately 1.5 to 2.5, 3.5 to 4.5, and 6- to 10-fold higher, respectively, in suprapituitary than peripheral blood, (b) different NE/DA and NE/E ratios in favor of DA and E in suprapituitary blood, and (c), a complete (100%) group separation (suprapituitary vs. peripheral) when discriminant analysis included only DA and E. These data indicate that suprapituitary blood composition is different from that of the peripheral blood, and is particularly rich in CAs and claimed differences between DA and E release on one hand and NE release on the other in suprapituitary blood also are observed. We advance the hypothesis of a hypothalamic source of such amines draining via median eminence into portal vasculature, and name this blood "hypothalamic-hypophysial blood." Besides serving as "classical" neurotransmitters, CAs may also have a direct neurohormonal role in the regulation of the human hypothalamic-hypophysial function.

Adult↗
PubMed1989

Granulopoiesis in tadpoles of Rana esculenta. Ultrastructural observations on the morphology and development of heterophil and basophil granules.

The morphology and development of heterophil and basophil granules from the trunk kidneys of Rana esculenta tadpoles were studied at the electron microscopic level. Cells of the heterophils series contain granules displaying either spheroid profiles with homogeneous content (Type A), or elongate profiles with a crystalloid interior (Type B). Type A granules apparently originate directly from Golgi-derived vesicles, which, gaining slightly in size and density, transform into the mature granules. Type B granules could be traced back to vacuolate structures showing an irregular content. Their development could be traced through increasingly elongated forms with the appearance of a characteristic crystalloid core. Fully developed basophil granules are considerably larger in size than heterophil granules and contain heterogeneous interna showing a central-cortical organisation: a finely stippled medullary zone of varying density is surrounded by a sickle-shaped and lamellate cortex (Type L), or a moderately dense and uniformly stippled medulla is enclosed by two diametrically opposed, cap-shaped, filamentous regions (Type F). The heterophil and basophil granules are compared to those in other vertebrates and possible phylogenetic aspects are discussed.

Animals↗
PubMed1989

Granulopoiesis in tadpoles of Rana esculenta. Ultrastructural observations on the developing granulocytes and on the development of eosinophil granules.

The morphology and development of the granules of developing eosinophils present in the trunk kidneys of Rana esculenta tadpoles has been studied at the ultrastructural level. During the differentiation of eosinophil granulocytes a single and morphologically unique population of cytoplasmic granules is present. Fully developed granules are spherical, membrane-limited, and have a dense and homogeneous content. Eosinophil granules have been traced back to Golgi-derived vacuoles which fuse and form immature granules containing a dense and knot-like precipitate. By condensation these immature granules transform into the definitive homogeneous forms. The eosinophil granules of Rana esculenta are compared to those in other vertebrates and possible phylogenetic aspects are discussed.

Animals↗
PubMed1989

[Complications caused by a Swan-Ganz catheter. An inadvertent entrapment in the right atrium during cardiac surgery].

Insertion of a Swan-Ganz catheter for measurement of pulmonary artery and pulmonary capillary wedge pressures is common for operative management of patients with borderline left ventricular function. However, use of the catheter has associated risks. This case report illustrates the inadvertent snaring, by a suture, of a Swan-Ganz line in the right atrium and its subsequent removal transvenously during rethoracotomy.

Catheterization, Swan-Ganz↗
PubMed1989

[Surgical therapy of life-threatening tachycardic cardiac arrhythmias in children].

Surgical techniques for tachyarrhythmias refractory to medical treatment are used with increasing frequency. Among 211 patients undergoing antiarrhythmic surgery 10 children (2 to 14 years old) were operated by electrophysiologically directed procedures. 7 patients suffered from WPW syndrome, 2 from focal atrial tachycardias and 1 from recurrent ventricular tachycardia following the repair of Fallot's tetralogy. In all cases preoperative electrophysiologic study and intraoperative mapping preceded operative ablation. Surgical treatment consisted of interruption of the bundle of Kent (3 right-sided, 2 left-sided, 3 septal), ablation of the atrial focus (1 right-sided, 1 left-sided) and right ventricular outflow tract incision. In 7 operations cryo-techniques were added. 2 children with WPW syndrome had two interventions because of tachycardia recurrences due to multiple accessory pathways. In 1 case a VVI-pacemaker was implanted postoperatively due to complete atrioventricular block. Another 2 children with prolonged postoperative bradycardia received a pacemaker prophylactically. Only the child with previous tetralogy of Fallot is still under antiarrhythmic medication while all other children are free of tachycardiac episodes. Our data confirm the efficacy of surgical treatment of tachyarrhythmias in children thereby abolishing the need for life-long antiarrhythmic medication.

Adolescent↗
PubMed1988

Identification of IL-6 as a T cell-derived factor that enhances the proliferative response of thymocytes to IL-4 and phorbol myristate acetate.

Thymocytes undergo a vigorous proliferative response when stimulated with a combination of IL-4 and PMA. We have found that conA-induced supernatants from a number of Th cell clones could enhance the level of IL-4/PMA-induced proliferation of unseparated thymocytes 0.5- to 2-fold and of peanut agglutinin-positive thymocytes 2- to 10-fold. These supernatants did not contain IL-2 or IFN-gamma, and the enhancing activity could be chromatographically separated from IL-3, -4, -5, and granulocyte/macrophage CSF. The possibility that the thymocyte enhancement factor contained in these supernatants was IL-6 was suggested when murine rIL-6 was found to have similar activity. Further evidence for the identity of these two factors was obtained when an IL-6 assay, based on plasmacytoma growth, was used to test column fractions showing thymocyte enhancement. All fractions active in the thymocyte enhancement assay also had activity in the plasmacytoma growth assay. These observations suggest that the thymocyte-stimulating activity present in the T cell supernatants was due to IL-6.

Adjuvants, Immunologic↗
PubMed1988

Manual gas-phase isothiocyanate degradation.

We describe a manual gas-phase isothiocyanate degradation procedure for the primary structure determination of proteins and peptides. The proteins and peptides are applied to a polybrene-coated glass fiber filter wedged into a small glass column. The phenylisothiocyanate is directly pipetted onto the filter disk. The coupling and cleavage reactions are performed in small desiccators containing trimethylamine and trifluoroacetic acid vapors, respectively. The wash and extraction steps are performed by allowing the suitable solvents to percolate through the filter disk. The extracted anilinothiazolinone is then converted to the phenylthiohydantoin and identified by any one of a number of described methods. Our results show that this method is very sensitive and that the reactions proceed faster than those of the published automated procedure. No expensive equipment is required and the manual degradation can be performed by a laboratory assistant. A large number of samples can be simultaneously subjected to the degradation under identical conditions, making this an ideal method for physicochemical investigations into the isothiocyanate degradation. We also use this method to screen HPLC fractions after enzymatic protein fragmentation. Manually sequenced glass filters can be transferred to the automated instrument for more extended degradations.

Amino Acid Sequence↗
PubMed1988

Reduced diastolic left ventricular posterior wall motion in patients with constrictive pericarditis--incidence, hemodynamic and clinical correlations.

In 24 patients with constrictive pericarditis proven by cardiac catheterization, the amplitude of diastolic left ventricular posterior wall motion was evaluated by M-mode echocardiography and compared to the results of 24 healthy volunteers. The amplitude was significantly less in constrictive pericarditis patients than in normal controls (0.3 +/- 0.2 mm versus 3.9 +/- 0.4 mm) (P less than 0.001). No constrictive pericarditis patient demonstrated a higher value than 2 mm whereas none of the healthy volunteers had an amplitude less than 3 mm. In 11 of 13 constrictive pericarditis patients who underwent pericardiectomy, an increase in amplitude was observed. In 6 patients the amplitude returned to normal limits after surgery. No significant correlation between the degree of heart failure or the level of left ventricular end-diastolic pressure and the reduction of the amplitude was found. In addition, the amplitude of left ventricular diastolic posterior wall motion did not allow a clear separation between patients who could be treated medically and those requiring pericardiectomy.

Adult↗
PubMed1988

Surgical alternatives in the treatment of life-threatening ventricular arrhythmias.

We present our experience in the treatment of life-threatening ventricular tachycardia using electrophysiologically guided surgery (97 patients), automatic implantable cardioverter defibrillator (AICD) (42 patients), and orthotopic heart transplantation (15 patients). Eighty-three percent of these patients had ischemic and 17%, nonischemic heart disease. Our results of electrophysiologically directed surgery show an early mortality of 10% and a recurrence of 5% in the ischemic group. In the nonischemic group, the recurrence was 45%. The AICD was implanted in 31 patients with ischemic heart disease, in 5 with ventricular dysplasia, and in 6 with dilative cardiomyopathy, the ejection fractions ranging from 12% to 65%, with a mean of 30%. Early and late mortalities were 5% and 19%, respectively. The AICD was effective in all patients. Survival rate at 1 year was 83% +/- 6.4%. Thirteen of 15 patients have survived heart transplantation for 3-20 months (mean: 11 months). Ejection fractions prior to transplantation ranged from less than 10% to 34% (mean: 16%). We conclude that electrophysiologically guided surgery is highly effective in most cases of ischemia-related ventricular tachycardia. The AICD is considered a palliative alternative in patients with either poor ventricular function, no electrophysiological substrate, or multimorphological tachycardia. Heart transplantation has to be considered especially in young patients in whom progression of the underlying disease can be anticipated. Bridging by AICD is possible when transplantation is not immediately available or recommendable.

Adolescent↗
PubMed1988

Rate-responsive pacing as compared to fixed-rate VVI pacing in patients after ablation of the atrioventricular conduction system.

In 44 patients with supraventricular arrhythmias various pacemakers were studied after closed-chest ablation of the atrioventricular conduction system. There were 22 patients with a rate-programmable VVI pacemaker (Group I), 15 patients with an activity mode (ACTIVITRAX 8400) (Group II) and seven patients with a QT-mode pacemaker (QUINTECH 911) (Group III). To study both physical work capacity and heart-rate behaviour, exercise testing was performed using a treadmill. Sixteen patients in Group I (72.7%) complained of shortness of breath during exercise in comparison to four patients (26.7%) in Group II and three patients (42.9%) in Group III. Normal physical work capacity was observed in three of 22 patients (13.6%) in Group I and in all patients in Groups II and III. The heart rate both increased and decreased more rapidly at the onset and end of the stress test, respectively, in patients with activity-mode compared to patients with QT-mode pacing systems. These data show that, despite successful His-bundle ablation, both dyspnea and decreased work capacity are observed when VVI pacemakers are used. In contrast, the use of rate-responsive pacing systems leads to better cardiac performance.

Adult↗
PubMed1988

Evaluation of global and regional left ventricular function using two-dimensional and M-mode echocardiography in patients with an automatic implantable cardioverter defibrillator.

The effects of glued epicardial patch electrodes of the automatic implantable cardioverter defibrillator on the left ventricular function was studied by two-dimensional and M-mode echocardiography in 15 patients. Pre- and postoperative end-diastolic and end-systolic left ventricular cross-sectional areas were evaluated using planimetry. Regional left ventricular wall motion at the level of the left ventricular patch electrode was analyzed by two end-diastolic and end-systolic perpendicular axes. Left ventricular end-diastolic and end-systolic diameters as well as E-point-septal-separation and fractional shortening were analyzed using M-mode echocardiography. The mean time interval between preoperative echocardiograms and implantation of the automatic defibrillator was 0.3 X 1.3 (less than 1-2) months. Postoperative echocardiograms were recorded 6.6 +/- 6.9 (0.5-24) months after implantation of the device. There were no significant differences between pre- and postoperative mean values of end-diastolic and end-systolic areas and axes as well as M-mode echocardiographic parameters. Our data show that left ventricular patch electrodes do not significantly alter global or regional left ventricular function in patients after implantation of the automatic defibrillator.

Adult↗
PubMed1988

Granulopoiesis in tadpoles of Rana esculenta. Survey of the organs involved.

The topography and nature of granulopoietic tissues appearing during the larval period of Rana esculenta have been investigated using light and electron microscopy. The formation of eosinophils and heterophils occurred in the interstices of the pronephros and opisthonephros, in the mesenchymal sheath surrounding the pronephric duct, as well as in the mesentery and mesenchymal coat of the bile duct and hepatic ducts. Developing basophils were very rare, being detectable only in the stroma of the trunk kidneys. The pronephric interstices additionally contained differentiating lymphocytes, the opisthonephric interstices differentiating lymphocytes and erythrocytes. In contrast, the mesenchymal sheath of the pronephric duct as well as the mesentery and the mesenchymatous coat of the bile duct and hepatic ducts were solely granulopoietic.

Animals↗
PubMed1988

Treatment of extensive aortic aneurysms by a new multiple-stage approach.

A new multiple-stage approach to extensive aneurysmal disease of the aorta is presented. The method is designed to obviate the proximal graft-to-aorta anastomosis in second-stage and third-stage aortic replacement to simplify and facilitate these operative steps. Since 1981 a total of 17 such procedures were performed in seven patients with dissecting and nondissecting aneurysms without deaths or complications related to the method.

Adult↗
PubMed1987

Comparisons between diastolic fluttering and reverse doming of anterior mitral leaflet in aortic regurgitation.

In 27 patients with aortic regurgitation and nine patients with associated aortic stenosis, the incidence of reverse doming was studied by two-dimensional echocardiography and was compared with diastolic fluttering of the mitral valve. Reverse doming could be identified in four of six patients (66.7%) with mild aortic regurgitation and in 20 of 21 patients (95.2%) with moderate or severe aortic regurgitation (p less than 0.05). Fluttering of the anterior mitral leaflet was observed in all patients with mild aortic insufficiency and in 19 of 21 patients (90.5%) with moderate or severe aortic insufficiency. In patients with associated aortic stenosis, reverse doming was observed in three patients (33.3%), whereas fluttering was seen in six patients (66.7%). After aortic valve replacement, reverse doming persisted in one patient with a paravalvular leak. Reverse doming or fluttering was not seen in healthy volunteers or in 10 patients with congestive cardiomyopathy. Our data indicate that reverse doming is a helpful parameter for the diagnosis of aortic regurgitation.

Adolescent↗