Biomedical subjects
Publications and source records attributed to C Brechenmacher.
A patient with disseminated lupus erythematosus developed mitral and aortic valve disease, requiring double valve replacement. The ultra-structure of the lesions of the endo- and myocardium are described, and their significance discussed.
Explore the source record for details and available documents.
Intractable tachycardia in a boy proved fatal at the age of one year. A cousin still living has the same problem. Special electrocardiographic studies in the boy demonstrated a consistent abnormality which included complete atrioventricular dissociation with a normal atrial rate but a ventricular rate usually about 240 beats/minute; a His bundle comples preceded each QRS and all QRS complexes were narrow and uniform in configuration without a delta wave. At postmortem examination there were changes due to congestive failure and the heart was enlarged but otherwise normal except for the His bundle. In its midportion the His bundle was split into several thin and irregular longitudinally oriented strands, within which there were many areas of focal degeneration. There was no myocarditis and no focal degeneration elsewhere in the heart. Although the etiology of this process is uncertain, some possibilities are discussed.
The authors described seven cases of supraventricular tachycardia with atrio-ventricular dissociation, associated with the activity of an automatic focus in the bundle of His. These tachycardias, which appear at birth or are discovered at a very young age, appear to be congenital and sometimes familial, and are always isolated, having no associated cardiac abnormality. They give rise to cardiac failure, which is more marked when the rate is high (180-260/mn) and particularly resistant to treatment. The most effective form of treatment is amiodarone, almost always used in combination with digitalis. The anatomical abnormality, which was studied in the first case, is a contricting fibrosis around the main trunk of the bundle of His, and the appearances are reminiscent of those found in conditions of congenital atrio-ventricular block.
A child of six who had had several losses of consciousness died suddenly during a spell of tachycardia. The EKG showed at times a type B Wolff-Parkinson-White syndrome, at times a Lown-Ganong-Levine syndrome. Intracavitary electrophysiological explorations had been carried out. The interest of this case lies in the comparison between these electrophysiological explorations and the histological examination of the normal and accessory conduction pathways. The short PR interval, which did not lengthen under the effect of premature atrial stimulation, was accounted for by the presence of atrio-His bundle tracts. The intermittent delta wave was due to Hissio-ventricular Mahaim fibres. These two accessory conduction pathways are considered as abnormal.
The atrio-His bundle tracts are very rare; only two have been found in 687 hearts studied histologically. These tracts have a similar appearance to those of the atrioventricular bundle and form a complete bypass of the atrioventricular node. In their presence the electrocardiogram may show a short or normal PR interval. They may be responsible for some cases of very rapid ventricular response to supraventricular arrhythmias.
A study has been conducted into the morphological arrangement of the atrioventricular junctional area of human heart. The area was investigated in infantile, child, young adult, middle-aged, and old nodes. Although marked individual and ageing variations were observed, a general pattern of nodal architecture could be distinguished. The junctional area was therefore divided into four areas: (1) a transitional zone, (2) the compact node, (3) the penetrating bundle, and (4) the branching bundle. The transitional zone was intermediate between atrial myocardium and compact nodal specialized myocardium, but itself exhibited specialized characteristics. An important connection of the zone was to the myocardium of the left side of the interatrial septum. The compact node was itself composed of two segments which approached each other anteriorly from the mitral and tricuspid extremities of the septal anulus fibrosus. The junction of compact node and penetrating bundle could not be distinguished using cytological criteria. It was arbitrarily defined as the last point to make contact with transitional cells. Tissue distal to this was considered as penetrating bundle. A bypass tract was defined as any fiber contacting the bundle distal to this point, but such tracts were not observed in normal hearts. The branching bundle originated at the point of bifurcation of the penetrating bundle.
The working party on ventricular preexcitation of the European Society of Cardiology has debated nomenclature of the syndrome at several meetings. This communication presents the terminology proposed by the morphologists within the study group on behalf of the other members. It is suggested that the problem should be approached on the basis of possibilities of avoiding the delay-producing area of the atrioventricular junctional region or short-circuiting the specialized ventricular conduction pathways. Thus we propose that the following pathways or contingencies are relevant to preexcitation: (1) accessory atrioventricular muscle bundles; (2) accessory nodoventricular muscle bundles, (3) atriofasicular bypass fibers, (4) fasciculoventricular accessory connections, (5) intranodal bypass fibers, and (6) nodal malformations. Each of these possibilities is defined, or, where only hypothetical, is discussed. In the case of the first two definitions, anatomical variations are indicated which satisfy the basic definition. Thus accessory atrioventricular bundles can be either septal or parietal, and can be composed of either specialized or nonspecialized myocardium. Nodoventricular bundles can connect either the transitional cell zone or the compact nodal region of the junctional area to the ventricular septum. Comparison is made of the new nomenclature with terms in present usage.
Correlation between the endocardial electrocardiographic recording and the histological findings of the conduction pathways in one case of apparent atrial standstill makes it possible to state the following facts: 1. The presence of a supranodal block through an intraatrial conduction disturbance. 2. The presence of James' fibres by-passing the upper part of Tawara node. 3. The functional character of these James' fivres which constitute, in view of the presence of lesions of the upper part of the Tawara node, the only possible pathway from the atria to the ventricles in this case. 4. The possibility to record the action potentials of James' fibres in that exceptional case. The histological examination made it possible also to recognize the anatomical lesions responsible for the idiopathic dilatation of the right atrium and of the apparent atrial standstill which represented the end-stage of an atrial rhythm disease.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
The authors recently reexamined the peripheral nerve biopsies from 42 patients with chronic inflammatory demyelinating polyneuropathy (CIDP). There were 27 males and 15 females, aged from 9 to 84 years, and 13 had relapses. No patient had vasculitis, monoclonal gammopathy, tumor, diabetes mellitus, Lyme disease, familial neuropathy, HIV, or any other immune deficiency. In the endoneurium, perivascular inflammatory cell infiltrates were present in only one case, but scattered histiocytes marked by KP1 on paraffin-embedded fragments were present in every case and there were no T-lymphocytes. At ultrastructural examination macrophage-associated demyelination was observed in 17 cases, of which 6 had relapses separated by intervals of several months or years. Axonal lesions without associated primary demyelination were observed in 4 cases and 3 of these had relapses. Thirty-two patients had mixed lesions of demyelination and axonal involvement. This study confirms other recent data indicating that in all cases of CIDP, macrophages are present in the endoneurium. Macrophage-associated demyelination is the characteristic feature of demyelinating forms. On the other hand, isolated primary axonal forms, which have been known since 1989, are relatively frequent and prone to relapses.
Intracellular pH was measured with the pH-sensitive fluorescent probe BCECF in spinal cord neurones cultured from rat embryos. At an external pH of 7.3, the average steady-state pHi was 7.18 +/- 0.03 (SEM, n = 97) and 7.02 +/- 0.01 (n = 221) in HEPES-buffered and in bicarbonate-buffered medium, respectively. In both external media, pHi was strongly dependent on external pH (pHe). In HEPES-buffered medium, pHi recovery following an acid load induced by transient application of ammonium required external Na+ and was inhibited by amiloride, indicating the presence of a Na+/H+ exchange. Na(+)- and HCO3(-)-dependent, DIDS-sensitive alkalinizing mechanisms also contributed to pHi regulation in CO2/bicarbonate-buffered medium. The presence of an electrogenic Na(+)-HCO3- cotransporter was confirmed by the alkalinizing effect of KCl application. The fact that pHi is lower in CO2/bicarbonate- than in HEPES-buffered medium and the alkalinization observed upon suppression of external Cl- suggest that the acidifying Cl-/HCO3- transporter plays an important role in defining pHi.
The authors reported a new family case of Steinert with twelve years follow-up. The study of potentials in the bundle of his was performed in all patients, showed an intra- and infra-hisian blocks. This study showed a discrepancy between muscular and myocardial evolutive injury, a very important knowledge for follow-up. Conduction disturbances were found in two cases and pacemaker insertion was performed in one patient. The authors specified the indication of electrophysiological studies during the onset and pacemaker implantation in all patient with a typical or suggestive history of syncope.
65 biopsies of peripheral nerve from patients suffering from Guillain-Barré syndrome were studied by electron microscopy. In 48 cases there was macrophagic invasion of the Schwann cells of certain myelinated fibers, and in 32 of these cases some myelin sheaths were stripped away by an elongated macrophagic process. Vesicular disruption of the myelin sheath was observed in only 8 cases and in less than 1% of the myelinated fibers. Uncompacted myelin lamellae were observed in a few myelinated fibers. These ultrastructural lesions are analysed and commented on with a view to selecting patients who are to undergo plasma exchange.