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Biomedical subjects

H Bertram

Publications and source records attributed to H Bertram.

At least 37 records · Page 2Linked to original sources
PubMed1999

Percutaneous transluminal angioplasty for the treatment of complete arterial occlusion after retrograde cardiac catheterization in infancy.

Nine patients with arterial thrombosis were treated with transcatheter recanalization and subsequent balloon dilation of the occluded vessel. Repeat angiography or duplex sonography 3 to 14 months after intervention showed completely patent arteries without restenosis in 7 patients; there was residual narrowing of the vessel in the remaining 2 patients.

Angiography↗
PubMed1998

Transcatheter recanalization and subsequent stent implantation for the treatment of early postoperative thrombosis of modified Blalock-Taussig shunts in two children.

Two babies with duct-dependent cyanotic congenital heart disease were palliated with modified Blalock-Taussig shunts. One patient was diagnosed to have tetralogy of Fallot, and the other patient, tricuspid atresia type Ia. Early postoperative arterial oxygen saturations dropped significantly due to shunt thrombosis. Both patients were successfully treated with angioplasty and stent implantation.

Angioplasty, Balloon, Coronary↗
PubMed1998

[Mechanical recanalization of venous thrombosis and pulmonary embolism with the Clotbuster thrombectomy system in a 12-year-old boy].

The treatment of patients with deep vein thrombosis and pulmonary embolism with contraindications for a thrombolytic therapy is a therapeutic challenge. We report on a 12 year old patient who was treated for large cell lymphoma according to NHL-BFM 95: Block AA protocol. During his therapy, he developed a thrombosis of his right femoral vein and pulmonary embolism affecting the left segments 4, 5, 8, and 9. Because of cerebral metastasis a fibrinolytic therapy was contraindicated. Therefore, we performed a mechanical thrombectomy using the Amplatz thrombectomy device. The postinterventional scintigraphy showed a markedly improved pulmonary perfusion; dopplersonography 4 months postinterventionally showed a patent right femoral vein.

Angiography↗
PubMed1998

[High frequency catheter ablation in young patients with permanent junctional reentry tachycardia and ectopic atrial tachycardia].

Ten young patients with a median age of 10.5 (range: 6 to 31) years suffering from the permanent form of junctional reciprocating tachycardia (PJRT; n = 7) and ectopic atrial tachycardia (AET; n = 3) were treated by transcatheter radiofrequency current application. Indications for interventional therapy were failure of medical therapy after a median of 3 antiarrhythmic drugs in all patients, syncope in 1, and impaired left ventricular function in 4 patients (PJRT n = 3, AET n = 1). The intervention was primarily successful in all patients. Median fluoroscopy time during the ablation procedure was 17 (10 to 70) minutes. A median of 3 (1 to 14) radiofrequency (500 kHz) pulses was delivered at a target temperature of 70 degrees C or with 30 W for 30 s. One patient had a recurrence of PJRT and was successfully treated by a repeat ablation. After a median follow-up of 14 (2 to 61) months, all patients are free of drug treatment and in normal sinus rhythm. Left ventricular function has normalized in patients with follow-up > 6 months. Radiofrequency catheter ablation was a safe and effective therapy in young patients with drug-resistant forms of chronic-permanent supraventricular tachycardia.

Adolescent↗
PubMed1998

Radiofrequency current application on immature porcine atrial myocardium: no evidence of areas of slow conduction after 12-month follow-up.

INTRODUCTION: Radiofrequency current (RFC) application is a widely used procedure for treatment of supraventricular arrhythmias. The purpose of this study was to investigate late electrophysiologic sequelae of RFC lesions at immature atrial myocardium in pigs, as they have not yet been systematically investigated in vitro. METHODS AND RESULTS: RFC application (temperature guided) was performed in seven piglets (mean age 6 weeks) by a steerable 6-French electrode catheter positioned at the lateral aspect of the tricuspid valve annulus. After 12 months, hearts were removed, and lesions with surrounding tissue were isolated. The viable tissue at the border of the specimen was paced with a cycle length of 500 and 600 msec. One hundred fifty impalements were performed on each specimen using capillary microelectrodes to record action potential characteristics from the lesion's surface and the surrounding tissue. In all seven specimens, no transmembrane action potentials from the fibrotic surface of each of the lesions could be recorded. The surrounding viable tissue was sharply demarcated electrically. No areas of slow conduction were detected. Action potential characteristics as mean maximum diastolic transmembrane potential, mean action potential duration at 90% repolarization, and upstroke velocity of phase 0 of the action potential were all normal. CONCLUSION: No evidence of areas of slow conduction 12 months after RFC application at immature atrial myocardium suggests that this technique is safe regarding occurrence of late atrial tachyarrhythmias after the procedure.

Action Potentials↗
PubMed1996

Familial idiopathic atrial fibrillation with bradyarrhythmia.

UNLABELLED: A 10-year-old boy is reported who presented with idiopathic atrial fibrillation and bradyarrhythmia. After history of intrauterine and postnatal bradycardia, atrial fibrillation was first documented electrocardiographically at 16 months of age. An underlying structural heart disease was not evident. At the age of 10 years, implantation of a permanent ventricular demand pacemaker was indicated after syncope due to severe bradyarrhythmia. The family history revealed five persons of four generations with bradyarrhythmias. Idiopathic atrial fibrillation known since childhood was documented in three close relatives. A high grade AV block resulting in bradyarrhythmias and the occurrence of ST-T-changes in precordial leads could be demonstrated in all affected family members suggesting a diffuse general conduction abnormality in these patients. In this family, idiopathic atrial fibrillation seems to be transmitted as an autosomal dominant trait. CONCLUSION: Atrial fibrillation without underlying heart disease is extremely rare in children. Careful electrocardiographic follow-up of these patients and the evaluation of ECG recordings of all family members is recommended.

Atrial Fibrillation↗
PubMed1996

[Permanent ventricular tachycardia in a 12-year-old boy: curative therapy by high frequency current ablation].

UNLABELLED: A 12-year old boy from Armenia presented with chronic permanent ventricular tachycardia (150/min) and reduced left ventricular shortening fraction (< 30%). Tachycardia was present > 20 h/day on several 24-h Holter monitorings. Diagnosis of ventricular tachycardia could be established on surface ECG by identification of atrioventricular dissociation and a right bundle branch block pattern with a R/S ratio < 1 in lead V6. Antiarrhythmic therapy with mexiletine and sotalol alone or in combination did not influence the presence of the dysrhythmia. During electrophysiological study, the dysrhythmia could not be terminated by administration of adenosine, ventricular extrastimuli, overdrive stimulation or direct current cardioversion. Endocardial mapping identified a region on the left ventricular surface of the anterior upper interventricular septum as the origin of the dysrhythmia. At this location stimulation at a cycle length shorter than the tachycardia produced a QRS complex nearly identical to the tachycardia QRS complex. Local ventricular electrogram preceded the onset of the tachycardia QRS complex on surface ECG by 23 ms. Radiofrequency current application with 30 W for 30 s resulted in permanent termination of the tachycardia. No complications occurred. Six months after the intervention, the boy is still in normal sinus rhythm. Left ventricular function normalized. CONCLUSION: Radiofrequency catheter ablation should be considered in young patients with drug-refractory chronic permanent ventricular tachycardia.

Bundle-Branch Block↗
PubMed1996

[Coronary sinus defects: rare form of interatrial communication].

UNLABELLED: A coronary sinus defect results in a communication of variable size between the coronary sinus (CS) and the left atrium (LA). It is in most cases associated with a persistent left superior vena cava (l-SVC) and an atrial septal defect of the coronary sinus type and often part of a more complex cardiac malformation. If the CS to LA fenestration is the single cardiac defect, this anomaly provides the basis of an unusual form of interatrial communication, which may cause diagnostic difficulties. Two patients with this rare anomaly are reported. A 9-year-old boy presented with history of mild cyanosis pronounced after physical activity (SaO2 < 90%) since the age of 3. Comprehensive pulmonary and cardiological diagnostic procedures in the referring hospital yielded normal findings. Finally, a 1-SVC draining into a mildly dilated coronary sinus could be demonstrated echocardiographically. Contrast echocardiography revealed a right-to-left-shunt at atrial level. Diagnosis of a partially unroofed coronary sinus was subsequently confirmed during cardiac catheterization. The second patient was primarily diagnosed echocardiographically to have an atrial septal defect of the primum type (ASD I) in the first year of life. After pulmonary vascular markings on chest-x-ray had increased, she was assigned to our hospital for cardiac catheterization. Slight arterial desaturation (SaO2 88%) was present due to a large l-SVC anomalously draining into the LA, the innominate vein was missing. The roof of the coronary sinus was predominantly absent. Combined with a large atrial septal defect of the coronary sinus type, this resulted in significant left-to-right-shunt and right-to-left-shunt at atrial level due to a pure unroofed coronary sinus. CONCLUSION: A coronary sinus defect with partial or complete unroofing of the CS and a persistent l-SVC should be considered in the differential diagnosis of an otherwise unexplained systemic desaturation and in patients with both left-to-right-shunt and right-to-left-shunt at atrial level.

Cardiac Catheterization↗
PubMed1993

On the cytotoxicity of irradiated media. To what extent are stable products of radial chain reactions in physiological saline responsible for cell death?

In a previous publication (Czapski et al. 1992) we reported that HOCl accounts for the toxicity of irradiated phosphate-buffered saline towards Escherichia coli bacterial cells. We have now investigated the respective toxicities towards lambda phage and mammalian cells. For phage, as with bacteria, cytotoxicity of the irradiated media seems to derive from HOCl without detectable contribution of H2O2. Mammalian cells (V79 CHO), in contrast, are more sensitive to H2O2 than to HOCl. Both agents, however, are not able to account quantitatively for the toxicity of irradiated solutions towards V79 cells; a hitherto unidentified chlorine/oxygen derivative--being formed in the sub-micromolar concentration range--is suggested to be responsible for toxicity in the case of eukaryotes.

Animals↗
PubMed1992

Radical effects on mutation spectra in lambda phage.

Mutations in the lambda repressor gene cI (710 bp) were induced by 60Co-gamma radiation in dissolved lambda phage DNA. After in vitro DNA packaging to lambda phage particles (pack phage) and phenotypic expression of the mutants, DNA was sequenced directly. Two-thirds of mutations were located in the amino terminus region of the gene without any signs of hotspots. Changes consisted of (+1) insertions (25%) and base substitutions (75%). Transitions were exclusively G/C to A/T. Transversions were mostly G/C to C/G and few G/C to T/A. We did not find A/T to T/A transversions, A/T to G/C transitions, deletions and gross rearrangements. In most of the base substitutions a pre-existing base pair had been replaced by an A/T pair; this might come from 'non-instructional sites' like abasic sites. Several mechanisms for base substitutions are considered.

Bacteriophage lambda↗
PubMed1992

[Neonatal variant of Bartter syndrome].

A male preterm infant of 32 weeks of gestation with history of severe polyhydramnios during pregnancy presented soon after birth with polyuria with initial sodium chloride loss subsequently followed by increasing potassium loss. After manifestation of hypokalaemia, hypochloraemia, alkalosis and high urinary prostaglandin concentrations, the diagnosis of the neonatal variant of Bartter's syndrome was made. The treatment consisted of administered of large amounts of fluid with sodium chloride and potassium supplementation and indomethacin (1.5 to 2 mg/kg per day).

Bartter Syndrome↗
PubMed1990

Evidence for a preglomerular oxygen diffusion shunt in rat renal cortex.

Although blood flow to the renal cortex is high and oxygen extraction is low, the renal cortex is remarkably susceptible to hypoxia. Because erythropoietin production has been localized mainly to the renal cortex, the aim of this study was to find a common denominator for both the high susceptibility to hypoxia and oxygen sensing within the renal cortex. By direct measurement of oxygen pressure with microcoaxial needle sensors at superficial glomeruli of the in situ kidney of anesthetized Munich-Wistar-Frömter rats, we obtained mean partial pressure of O2 (PO2) values of 46 +/- 13 (SD) mmHg (n = 71). The simultaneously measured systemic PO2 in arterial blood was 90 +/- 8 mmHg (n = 54). Changing the respirator gas from air to pure oxygen enhanced systemic arterial PO2 to 593 +/- 27 mmHg, whereas PO2 at the superficial glomeruli increased only to a mean of 80 +/- 28 mmHg (n = 71). These data suggest significant preglomerular shunting of oxygen within the cortical vasculature, most likely between interlobular vessels, which are arranged in a countercurrent fashion and represent quantitatively the largest contact area between arteries and veins within the renal cortex.

Air↗
PubMed1990

Osteolysis in alloarthroplasty of the hip. The role of bone cement fragmentation.

Movement at the interface between bone and cement and fractures of the cement can cause fragmentation of the polymethylmethacrylate (PMMA) bone cement implant. In order to obtain further information about the effect of PMMA fragments on the surrounding tissue and the role of such particles in the development of bone resorption, the authors investigated 17 patients with cemented total hip endoprostheses showing osteolysis and implant loosening in the femoral shaft with (Group B) and without (Group A) involvement of the acetabulum. The roentgenographic follow-up examinations revealed an initially slow and later more rapid extension of the endosteal bone erosions, with a predilection for the tip of the stem, the lesser trochanter, and laterally for the middle of the stem. At revision surgery, tissue samples were taken from the joint capsule and the bone-cement interface, in particular from the osteolysis in the femoral shaft and the acetabulum. The tissue samples were processed for histology, microscopically examined, and semiquantitatively evaluated. The retrieved devices were also carefully inspected. Large foreign-body granulomas were found at the bone-cement interface and in the joint capsule. Histiocytes and foreign-body giant cells stored particles of PMMA and polyethylene, of which fragmented bone cement predominated. Granulomatous tissue invaded bone canals and marrow spaces and induced resorption of the surrounding bone. In four cases in Group A, tissue from the osteolysis contained only fragmented bone cement, demonstrating that PMMA particles alone may be responsible for triggering focal bone resorption. Osteolysis seems to begin at the site where disintegration of bone cement begins. In cases in which polyethylene particles were found in the tissue in addition to fragmented bone cement, wear from the ultrahigh molecular weight polyethylene socket has been increased by entrapment of PMMA particles between the joint surfaces. Thus, fragmentation of bone cement and abrasion of polyethylene enhance each other. Bone cement particles promote polyethylene wear, which in turn promotes granuloma formation, bone resorption, and subsequent bone cement disintegration.

Acetabulum↗
PubMed1990

Osteolysis in alloarthroplasty of the hip. The role of ultra-high molecular weight polyethylene wear particles.

Massive localized osteolysis around artificial joints has been seen more frequently in the past few years. It is still not generally accepted that ultra-high molecular weight polyethylene (UHMWPE) wear particles can induce massive bone resorption, even distant from the joint. This article describes a series of eight soft-top prostheses with large UHMWPE ball heads that contributed to the erosion of surrounding bone. Roentgenographically, all of the cases showed a marked loss of proximal cortical bone, more or less combined with osteolysis, which was distal to the femoral shaft and deep into the acetabulum. In two cases, remodeling and resorption transformed the bone into a tumorlike appearance. Tissue samples from areas of osteolysis as well as from the joint capsule were taken at revision surgery, processed for histology, examined microscopically, and evaluated semiquantitatively. The retrieved devices were also carefully inspected. Large amounts of UHMWPE wear debris were found not only in the joint capsule but also in layers of granulomatous tissue from the acetabulum and femur, whereas metal particles and fragmented polymethylmethacrylate were either completely absent or occurred only in very small amounts. The results of this study demonstrate that UHMWPE wear products alone can cause massive osteolysis by triggering foreign-body granuloma formation at the bone-cement interface; the bone cement may remain fixed in areas beyond the osteolytic transformation.

Acetabulum↗
PubMed1988

Action of gamma endonuclease on clustered lesions in irradiated DNA.

Irradiation of DNA in situ i.e. in phage particles or in the cell leads to alterations of single DNA nucleotides as well as to clustered lesions such as double strand breaks or unpaired DNA regions the latter being sensitive to digestion by S1 nuclease. A contribution will be made to the configuration of such S1-nuclease-sensitive sites (S1 sites). DNA from irradiated lambda phage containing S1 sites was treated with gamma endonuclease from M. luteus which is known to split the nucleotide strand at the position of oxidized pyrimidine base. It was found that the gamma endonuclease induces double-strand breaks at some of the S1 sites indicating double base damage within this site. However, half of the S1 sites are not converted into a double-strand break by the gamma endonuclease, indicating base damage only on one strand within the unpaired region.

Aspergillus oryzae↗