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F Bode

Publications and source records attributed to F Bode.

At least 37 records · Page 2Linked to original sources
PubMed1998

Should unipolar leads be implanted in the atrium? A Holter electrocardiographic comparison of threshold adapted unipolar and high sensitive bipolar sensing.

The accuracy of atrial sensing plays a central role in dual chamber pacing. Recent Holter electrocardiographic studies showed a high incidence of atrial malsensing. We investigated the efficacy of bipolar atrial sensing at high sensitivity compared to threshold adapted unipolar sensing. One hundred consecutive patients with identical dual chamber pacemakers and bipolar atrial leads were investigated. Mean and individual range of 40 unipolar and bipolar telemetered atrial potentials were calculated; sensing threshold was determined by a semiautomatic sensing test. Oversensing was investigated with the help of a muscle provocation test. Twenty-four-hour Holter monitoring was performed at the highest bipolar sensitivity as well as at a unipolar sensitivity of half the measured sensing threshold. Mean atrial potential was significantly lower during bipolar mode compared to the unipolar sensing configuration, 3.66 +/- 1.75 versus 3.85 +/- 1.62 mV, P = 0.02. The bipolar atrial potentials showed a higher individual range than the unipolar signals, 2.44 +/- 2.62 versus 1.79 +/- 0.92 mV, P < 0.01. Sensing threshold did not differ significantly, 2.76 +/- 1.33 versus 2.67 +/- 1.29 mV. Mean oversensing threshold was 1.21 mV at unipolar configuration, whereas oversensing could not be provoked at a bipolar sensitivity of 0.5 mV. The incidence of atrial undersensing was significantly higher at threshold adapted unipolar sensing compared to bipolar sensing at highest atrial sensitivity, 35% versus 22%, P = 0.04. Oversensing did not occur at bipolar sensing, but was observed in 56% of patients at unipolar mode. Thirty-two percent of patients showed both atrial undersensing and oversensing at the unipolar sensing configuration. The muscle provocation test reached a sensitivity of 89% and a specificity of 95% in prediction of atrial oversensing during daily life. In conclusion, unipolar atrial potentials are more stable than bipolar ones. On the other hand, bipolar atrial sensing is less prone to the perception of myopotentials. Programming a high bipolar sensitivity significantly improves atrial sensing. Thus, bipolar leads should generally be implanted in the atrium.

Aged↗
PubMed1998

Differential effects of defibrillation on systemic and cardiac sympathetic activity.

OBJECTIVE: To assess the effect of defibrillation shocks on cardiac and circulating catecholamines. DESIGN: Prospective examination of myocardial catecholamine balance during dc shock by simultaneous determination of arterial and coronary sinus plasma concentrations. Internal countershocks (10-34 J) were applied in 30 patients after initiation of ventricular fibrillation for a routine implantable cardioverter defibrillator test. Another 10 patients were externally cardioverted (50-360 J) for atrial fibrillation. MAIN OUTCOME MEASURES: Transcardiac noradrenaline, adrenaline, and lactate gradients immediately after the shock. RESULTS: After internal shock, arterial noradrenaline increased from a mean (SD) of 263 (128) pg/ml at baseline to 370 (148) pg/ml (p = 0.001), while coronary sinus noradrenaline fell from 448 (292) to 363 (216) pg/ml (p = 0.01), reflecting a shift from cardiac net release to net uptake. After external shock delivery, there was a similar increase in arterial noradrenaline, from 260 (112) to 459 (200) pg/ml (p = 0.03), while coronary sinus noradrenaline remained unchanged. Systemic adrenaline increased 11-fold after external shock (p = 0.01), outlasting the threefold rise following internal shock (p = 0.001). In both groups, a negative transmyocardial adrenaline gradient at baseline decreased further, indicating enhanced myocardial uptake. Cardiac lactate production occurred after ventricular fibrillation and internal shock, but not after external cardioversion, so the neurohumoral changes resulted from the defibrillation process and not from alterations in oxidative metabolism. CONCLUSIONS: A dc shock induces marked systemic sympathoadrenal and sympathoneuronal activation, but attenuates cardiac sympathetic activity. This might promote the transient myocardial depression observed after electrical discharge to the heart.

Adult↗
PubMed1997

[Atrial sensing and atrioventricular synchrony in single lead VDD pacemakers. Can the appearance of atrial undersensing be predicted?].

Single-lead VDD-pacing is an alternative to DDD-systems in patients with AV-block and normal sinus node function. Atrial sensing plays a central role in these pacemakers. AV-synchrony, incidence of atrial arrhythmias and the occurrence of sinus node disease were investigated in 108 patients with VDD-pacemakers followed over a mean period of 24.8 months after implantation. Determinants influencing the occurrence of atrial undersensing were especially focused on. Mean atrial potential and sensing threshold were reduced within the first 2 weeks after implantation (p < 0.01). Intermittent atrial undersensing occurred in 25.9% of patients and was observed in 82.1% of these patients within the first 2 weeks after implantation. Positioning the atrial dipole in the low right atrium showed a significantly higher incidence of atrial undersensing (42% in comparison to 24% in the other positions). In a multivariate analysis including intra- and postoperative measurements as well as characteristics of the pacemakers and leads, it was the only parameter significantly (p < 0.02) correlated to the occurrence of atrial undersensing. Atrial fibrillation was observed in 4.6% of patients, a sinus node disease became evident in 2.7% of patients; 92.6% of patients remained in the AV-synchronous mode. Intermittent atrial undersensing is common in single-lead VDD-pacemakers and difficult to provide during implantation. The atrial dipole should not be positioned in the low right atrium and highest atrial sensitivity should generally be programmed. Nevertheless, VDD-pacing achieves an AV-synchrony comparable to DDD-pacemakers.

Aged↗
PubMed1994

Prolongation of monophasic action potential duration and the refractory period in the human heart by tedisamil, a new potassium-blocking agent.

The effect of intravenous tedisamil (0.3 mg.kg-1), a newly developed potassium-blocking agent, on ventricular repolarization was studied in 10 patients (three women, seven men; mean age 53 +/- 8 years) with coronary artery disease (stenoses < or = 60%). Left ventricular monophasic action potentials, effective refractory periods and surface electrocardiograms were recorded during sinus rhythm and during constant atrial pacing at cycle lengths of 600, 500 and 400 ms. Under tedisamil there was a 12% reduction of heart rate and in parallel a prolongation of QTc interval (+10%) and left ventricular monophasic action potential duration (+16% at 90% repolarization). QRS duration remained unchanged. Tedisamil increased the duration of monophasic action potentials during constant atrial pacing, indicating a direct prolongation effect on left ventricular repolarization independent of sinus node activity. By increasing the atrial pacing rate this prolonging effect diminished. Left ventricular effective refractory periods also increased in a frequency-dependent fashion with a greater prolongation effect at long cycle lengths as compared to short cycle lengths. The ratio between effective refractory period and monophasic action potential duration, however, remained constant, independent of heart rate. We conclude that tedisamil is bradycardiac at the dose tested and has a reverse use dependent prolongation effect on left ventricular repolarization and refractoriness. The electrophysiologic profile is consistent with a class III antiarrhythmic classification.

Action Potentials↗
PubMed1991

Quantitative skin prick and bronchial provocation tests with platinum salt.

Occupational asthma due to platinum salts is a frequent disease in platinum refineries. The diagnosis is based upon a history of work related symptoms and a positive skin prick test with platinum salts. Bronchial provocation tests have not been performed in epidemiological studies because the skin test is believed to be highly specific and sensitive. As no reliable data about this issue currently exist, this study assesses the use of skin prick and bronchial provocation tests with methacholine and platinum salt in platinum refinery workers. Twenty seven of 35 workers, who were referred to our clinic with work related symptoms and nine control subjects with bronchial hyperreactivity underwent a skin prick test and bronchial provocation with methacholine and platinum salt. For skin prick and bronchial provocation tests with platinum salt a 10(-2)-10(-8) mol/l hexachloroplatinic acid solution, in 10-fold dilutions was used. Four of the 27 subjects and all controls showed neither a bronchial reaction nor a skin reaction. Twenty three subjects were considered allergic to platinum salt; 22 of these showed a fall of 50% or more in specific airway conductance after inhalation of the platinum salt solution. Four workers experienced a positive bronchial reaction despite a negative skin prick test. No correlation of responsiveness to methacholine with responsiveness to platinum salt was found, but the skin prick test correlated with the bronchial reaction to platinum salt (rs = 0.50, p less than 0.023, n = 22). One dual reaction was seen in bronchial provocation tests. Side effects of both skin tests and bronchial provocation tests with platinum salt were rare and were not encountered in workers without a skin reaction to platinum salt. It is concluded that bronchial provocation tests with platinum salts should be performed on workers with work related symptoms but negative skin tests with platinum salts.

Adult↗
PubMed1989

Computer analysis reveals changes in renal Na+-glucose cotransporter in diabetic rats.

A novel, computer-assisted program was developed to analyze the time course of Na+-glucose cotransport by rat renal cortical brush-border membrane vesicles (BBMV). Transporter characteristics can be measured, which routine kinetic analyses fail to distinguish: cotransporter membrane density is derived from the picomoles of D-glucose bound per milligram of protein. Binding is stereospecific, blocked by phlorizin, and supported equally well by Na+ or K+ (but not Cs+). Quasi-first-order influx and efflux rate constants for the composite Na+-driven influx and the (presumed) Na+-independent efflux processes were highly dependent on glucose concentration. Either two Na+-glucose transporters exist in proximal tubules or a single mechanism abruptly changes rate when glucose falls to low levels. The major operation mode is slow, has a high capacity but low affinity, and may have a 2 Na+:2 glucose stoichiometry (Hill coefficient is unity). The minor system is a fast, smaller-capacity, higher-affinity operation with a 2 Na+:1 glucose stoichiometry that was not distinguishable when the same data were analyzed in conventional kinetic plots. Results with streptozocin-induced diabetic rats illustrate the method's utility. Low-glucose-affinity cotransporters were upregulated in hyperglycemic, but not in cachectic, ketoacidotic animals. Rate constants, especially for efflux, were decreased in diabetes.

Animals↗
PubMed1989

Amniotic fluid isoamylase activity in uneventful pregnancies.

A kinetic test (Phadebas) was used to determine the isoamylase activity in 50 serum specimens and 159 samples of amniotic fluid. A highly significant difference between the isoamylase patterns of serum and amniotic fluid was ascertained which strongly supports the view that amylase activity in amniotic fluid is not of maternal origin. During the whole course of gestation the activity of pancreatic isoamylase was constantly low whereas there was an increase of nonpancreatic activity (S-type amylase) from 44 +/- 10 U/l in the 18th week of gestation to 445 +/- 170 U/l in week 39/40. A comparison between the dispersion of the ascertained values and the lecithin-sphingomyelin (L/S) ratio showed a clear overlapping. There was a correlation coefficient of r = 0.645 for 115 amniotic fluid specimens examined in our investigation. The findings show that the estimation of nonpancreatic isoamylase (S-type amylase) activity in amniotic fluid is a valuable indirect parameter for determining fetal maturity and fetal lung maturity. The easy and quick determination method will provide even those hospitals with an index of fetal maturity which are presently not in a position to estimate the L/S ratio, thus being of great assistance in the field of premature deliveries.

Amniotic Fluid↗
PubMed1985

Kinetic studies of D-glucose transport in renal brush-border membrane vesicles of streptozotocin-induced diabetic rats.

Renal brush-border membrane vesicles prepared from streptozotocin-induced 4-day-diabetic rats possessed a Na+-dependent D-glucose transport system that exhibited apparent Kt and Vmax values about 2-fold greater than normal. Apparently, hyperglycemia and probably other stimuli cause the induction and membrane incorporation of a low-affinity transporter in these membranes; this increased sugar-transport capacity is retained for at least 4 weeks so long as the animals maintained or increased their body weight. Membranes prepared from 28-day-diabetic, severely ill ketoacidotic animals lose this enhanced transport ability and the decrease in Vmax was found to correlate directly with the weight loss. Furthermore, the transporter in brush-border membranes prepared from these cachectic animals had an even lower affinity for glucose than those from the acute hyperglycemic animals. That these changes in the diabetic animals represent major alterations in renal brush-border membrane construction is further supported by our observation that the specific activity of the marker enzymes, alkaline phosphatase and neutral alpha-glucosidase, are profoundly increased and decreased, respectively, in this condition.

Alkaline Phosphatase↗
PubMed1985

Inhibition of protein reabsorption in the renal proximal tubule by basic amino acids.

The effects of basic and neutral amino acids on the reabsorption of 125I-lysozyme by the renal proximal tubule were examined in rats. In whole animal experiments control animals were given an intravenous (i.v.) injection of 125I-lysozyme alone while experimental animals received an i.v. injection of either a basic or a neutral amino acid prior to the injection of 125I-lysozyme. In control animals the renal content of 125I-lysozyme 30 min after injection was 35% of the injected dose. After injection of basic amino acids there was a significant decrease in the renal uptake of lysozyme. There was no effect of neutral amino acids on the reabsorption of lysozyme. In microperfusion experiments proximal convoluted tubules were perfused in vivo for 3 min with a solution containing 125I-lysozyme and either lysine or alanine. In tubules perfused with lysine there was a significant decrease in the reabsorption of lysozyme, whereas alanine had no effect on lysozyme uptake. Electron microscope autoradiography revealed that lysozyme was located in endocytic vesicles and lysosomes in both experimental groups. However, the autoradiographic grain density was significantly decreased in tubules perfused with lysine as compared with those perfused with alanine. These findings demonstrate that basic amino acids inhibit the reabsorption of the cationic protein lysozyme by the proximal tubule cells.

Absorption↗
PubMed1983

Binding of lysozyme to brush border membranes of rat kidney.

The binding of 125I-labelled egg-white lysozyme to isolated brush border membranes of rat kidney cortex was investigated. The lysozyme binding was reversible and saturable. The Scatchard plot revealed a one-component binding type with a dissociation constant of 7.8 microM and 15.6 nmol/mg membrane protein for the number of binding sites. The binding of the basic lysozyme could be reduced by basic amino acids such as L-lysine, L-ornithine or L-arginine, while neutral amino acids such as L-citrulline or L-alanine had no effect. The inhibitory effect of lysine was competitive.

Animals↗
PubMed1982

[Perforations of the oesophagus (author's transl)].

The different reasons for perforations of the oesophagus are listed with their preferential locations. A survey is given on the necessary x-ray diagnostics including computed tomography according to the clinical signs. Examples of the characteristic x-ray findings and follow-up are demonstrated with their relation to the surgical possibilities.

Adult↗
PubMed1980

[Immunity reaction in old age (author's transl)].

It was found that 61 per cent of ageing persons (average age 73 years) had no protective concentrations of tetanus antitoxin in their serums. After active immunization with a vaccine (tetanus toxoid) the increase of the tetanus antitoxin concentration was slower and lower in old age compared to the young age.

Adolescent↗
PubMed1980

[Immunity reaction in old age (author's transl)].

In 20 persons in old age and in 20 young persons the immunization with 0,5 ml of a vaccine (tetanus toxoid) was performed. The cell--immediated immunity of lymphocytes of these probands were investigated on the 0,7 21. and 28. day by lymphocyte-transformation test and E-rosette test. The boostering followed after 21 days with the same dose of the vaccine. It was found that the spontaneous transformation rate in T-lymphocytes in old age compared to the young age was duplicated. The stimulation with PHA (Phytämagglutinin) showed no significant differences while the specific cellular reactivity of the T-cells in old age is delayed and reduced compared to the T-cells in young age.

Adolescent↗
PubMed1977

Effect of parathyroid hormone and cyclic adenosine 3',5'-monophosphate on isotonic fluid reabsorption: polarity of proximal tubular cells.

Isotomic fluid reabsorption (JV) of rat renal proximal tubules was examined by the shrinking droplet method in combination with simulatneous perfusion of blood capillaries. Sensitivity of JV measurement was improved by using each punctured tubule for control measurements: 1) Parathyroid hormoen (PTH) on the contraluminal cell side reduced JV in a dose-response behavior. The maximal inhibition was achieved at a PTH concentration of 10(-5) M, the half maximal inhibition at a concentration of 3 X 10(-9) M. PTH on the luminal cell side had a small inhibitory effect. 2) Cyclic AMP inhibited JV preferentially when applied to the luminal cell side. On the luminal cell side, both cyclic AMP and dibutyryl cyclic AMP inhibited JV in a similar dose-dependent behavior. Concentrations of both nucleotides as low as 10(-10) M had a definite inhibitory effect. Tested at a high concentration, N6-butyryl cyclic AMP was almost as effective as cyclic AMP. Deoxy cyclic AMP, 5' AMP, cyclic guanosine monophosphate (cyclic GMP), dibutyryl cyclic GMP had no effect. ATP inhibited JV to a very small extent. 3) The reduction of JV after administration of PTH and dibutyryl cyclic AMP was not additive. The similar inhibitory effect of PTH at the contraluminal cell face and of cyclic AMP at the luminal cell face suggests the following sequence of events in the mediation of the action of PTH: 1) activation of adenylate cyclase by PTH in the contraluminal cell membrane, and 2) action of the generated cyclic AMP on the luminal cell membrane. The interaction of cyclic AMP and the luminal cell membrane is initiated at the luminal cell surface.

Absorption↗
PubMed1976

Diagnosis of obstruction of the upper and central airways.

Patients with obstruction of the upper airways are often treated for long periods of time for other disorders. Correct diagnosis is important since treatment is quite specific. Such patients may present with a characteristic history and findings on physical examination. Certain physiologic tests such as flow-volume loops with and without helium help to prove the diagnosis. Patients with upper airway obstruction may also have sleep apneas and the sleep deprivation syndrome. Methods of diagnosis of upper airway obstruction are presented and three instructive cases are reviewed.

Airway Obstruction↗