Amplitude and Direction of Atrial Depolarization Using a Multipolar Floating Catheter: Principles for a Single Lead VDD Pacing

VDD stimulation using a single catheter for atrial sensing and ventricular sensing and pacing has become a reality. In order to compare the quality of the cavitary atrial electrogram (AEG) and to determine the intraatrial P wave direction and conduction time (CT), we compared, in an acute study, three different types of atrial electrode systems using four different leads, in 53 patients in sinus rhythm. The three electrode systems were: (1) one experimental system with quadripolar orthogonal electrodes using the Goldreyer concept; (2) one experimental system with quadripolar whole ring electrodes; (3) two systems with diagonally oriented half-ring electrodes, one experimental quadripolar and one bipolar CCS commercial (Polysafe A-Track lead). For the experimental systems, the four electrodes forming two independent bipolar pairs were situated on the intraatrial floating portion of a single lead and one supplemental electrode was distally positioned in the right ventricular apex. Bipolar AEGs were recorded at the high and at the low levels of the right atrium. For the CCS lead, the single bipolar AEG was recorded at the high level of the right atrium only. The highest AEG amplitude and the highest values for ventricular far-field rejection were provided by both diagonally oriented half-ring electrodes at the high atrial level and by the whole ring electrodes at the low atrial level. For both atrial levels, the orthogonal electrode system provided the smallest AEG amplitudes, the highest ventricular electrogram amplitudes, and therefore, the smallest values for ventricular far-field rejection.(ABSTRACT TRUNCATED AT 250 WORDS)     

Differences in clinical behaviour and immunophenotype between primary cutaneous and primary nodal anaplastic large cell lymphoma of T-cell or null cell phenotype

The histological, immunophenotypic and clinical features of 19 primary cutaneous anaplastic large cell lymphomas (cutaneous ALCL) were compared with those of 18 primary nodal anaplastic large cell lymphomas (nodal ALCL) of T-cell or null cell type. Although cutaneous ALCL and nodal ALCL had identical morphological features, differences in surface marker expression and clinical behaviour were found. Immunophenotypical differences concerned the expression of epithelial membrane antigen (82% of the nodal ALCL were positive v. none of the cutaneous ALCL) and the cutaneous lymphocyte antigen (HECA-452), a possible skin-homing receptor on cutaneous T-lymphocytes (most tumour cells in 44% of cutaneous ALCL cases were positive, whereas nodal ALCL showed expression of HECA-452 on only few tumour cells (< 25%) in 18% of cases tested). Loss of T-cell markers was more pronounced for nodal ALCL. Patients with cutaneous ALCL were generally older (median 61 years) than patients with nodal ALCL (median 24 years) and, in contrast to the latter group, did not show bimodal age distribution. Survival after 4 years, using lymphoma-related death as an end-point, differed significantly between cutaneous ALCL and nodal ALCL; 92% for cutaneous ALCL and 65% for nodal ALCL ( P =0.04). The better survival of cutaneous ALCL patients could not be ascribed to differences in age, stage or initial mode of treatment. These data indicate that differences in ismmunophenotype and clinical behaviour exist between morphologically identical primary cutaneous and primary node-based ALCL. They indicate that the primary site is an important prognostic factor in predicting the clinical outcome of ALCL.     

Rapid verification of the identity of questionable specimens using immunohistochemistry with monoclonal antibodies directed against HLA-class I antigens

 

Aims:

A case report is presented in which an unexpected pathological diagnosis raised the possibility that biopsies of two patients were mixed-up. Since these biopsies were obtained from kidney transplant patients, the HLA-typings of both patients were known.  

Methods and results:

We developed an immunohistochemical method using HLA-class I specific monoclonal antibodies to recognize the donor and recipient antigens in these biopsies. Using this method we could confirm the identity of the patients of whom the biopsies had been taken.  

Conclusions:

This method, which uses the highly polymorphic HLA-system, is potentially useful for rapid and easy verification of the identity of specimens if a mix-up is suspected.     

The amount of white pulp in the spleen; a morphometrical study done in methacrylate-embedded splenectomy specimens

This report deals with a morphometrical study on 92 surgically removed human spleens, to investigate the composition of spleens which are considered to be normal, i.e. spleens which had ruptured in traffic accidents or which had been incidentally removed during abdominal operations. A comparison was made with 16 spleens with hypersequestration of platelets and to 11 with hyper-sequestration of erythrocytes. Methyl-methacrylate embedding was used because of the superiority of this technique over conventional paraffin embedding. Significant differences were found between both 'normal' groups as to the absolute and relative amount of white pulp as well as the perifollicular red pulp zone. Based also on the few morphometrical reported studies in the literature, spleens removed during abdominal surgery form the best control group. Traumatic rupture of the spleen in traffic accidents might specifically occur in spleens which already contained a stimulated lymphatic compartment. A probably non-specific increase of white pulp was found in splenomegaly of varied aetiology. An expected influence of age on weight and composition of the spleen was not found in our study. The spleen changes in weight and composition only up to 5 years of age. Significant involution at older age was not found in ours nor in other reported larger series.     

The splenic red pulp; a histomorphometrical study in splenectomy specimens embedded in methylmethacrylate

The anatomy and pathology of the splenic red pulp was studied in three-dimensional reconstructions of methylmethacrylate embedded blocks of tissue obtained after splenectomy, as well as by morphometrical analysis of a large number of specimens. The sinuses of the spleen form a plexus of anastomosing vessels with remarkable buds. Capillaries end as sheathed capillaries in the cord tissue, the 'filtering' area, but a large proportion of the red pulp cords appear to be 'non-filtering'. These might form part of the lymphatic compartment, which is separate from the white pulp and its extension along the capillaries. This area has not yet been described in man. The change in the volume and structure of the various components of the red pulp were studied in 60 controls and in cases of traumatic rupture, idiopathic thrombocytopenic purpura, aplastic anaemia, autoimmune haemolytic anaemia, congenital spherocytosis, splenic congestion, and Hodgkin's disease. Significant differences were found in the volume of filtering and non-filtering areas, the size of the sinus compartment, and the degree of vascularization; these differences were only partially expected, for instance in disorders with excessive erythrocyte sequestration. A decrease of the 'non-filtering' area in Hodgkin's disease might indicate an unknown aspect of this disease. In agreement with our previous paper on the amount of white pulp, spleens removed because of traumatic rupture and those incidentally removed during abdominal surgery may not be combined as a single control group, because of significant and probably functional differences in the composition also of the red pulp.     

Effective treatment of experimental lupus nephritis by combined administration of anti-CD11a and anti-CD54 antibodies

Mice with chronic graft-versus-host disease (GVHD), induced by injection of DBA/2 lymphocytes in (C57BL10*DBA/2) F₁ hybrids, develop a syndrome resembling systemic lupus erythematosus (SLE) with immune complex glomerulonephritis. In this model we evaluated the role of interactions between CD11a (LFA-1α) and CD54 (intercellular adhesion molecule-1 (ICAM-1)) molecules on leucocytes in the development of renal disease in systemic autoimmunity. Two weeks after induction of GVHD, when anti-nuclear autoantibodies were detected in the circulation and immune complexes had formed in the glomeruli, mice were injected twice per week with rat anti-CD11a and anti-CD54 MoAbs, or with their vehicle PBS, or with control rat IgG. MoAb treatment significantly lowered albuminuria and increased survival compared with control mice with GVHD. In the glomeruli of MoAb-treated mice there was markedly less binding of immunoglobulin and C3, while anti-renal tubular epithelium autoantibodies, but not anti-glomerular basement membrane autoantibodies, were significantly lowered in the circulation 4 weeks after disease induction. In addition, MoAb treatment inhibited the glomerular influx of CD11a⁺ cells and decreased development of histological abnormalities in the kidneys. Both rat IgG- and MoAb-treated mice developed anti-rat immunoglobulin antibodies. Furthermore, a marked splenomegaly with an increase of the T cell compartment was observed in MoAb-treated mice with GVHD. These results show that CD11a/CD54 interactions are crucial for the full-blown development of lupus nephritis in this model. Treatment aimed at blocking the activity of these molecules profoundly attenuated the development of renal disease in chronic GVHD even if started when first symptoms of SLE (i.e. anti-nuclear autoantibodies in sera and glomerular binding of immunoglobulins) were already detectable.     

The human spleen; a histological study in splenectomy specimens embedded in methylmethacrylate

In a series of 316 surgically removed spleens, a histological and supportive immunohistological study was performed on methylmethacrylate sections. The structure of the human white and red pulp differs from the rat spleen in many respects, e.g. the human lacks the marginal sinus and the architecture of the periarteriolar lymph sheath seen in the rat. In man, the lymphoid compartment is in both white and red pulps. In the white pulp separate periarteriolar T-cell areas contain a large lymph-vessel plexus, which was reconstructed in serial sections. The circulation in the red pulp is discussed. The area between the red and white pulp, the perifollicular zone, is not the equivalent of the marginal sinus in the rat. Its anatomy in man suggests that it is an area formed from red pulp during the expansion of new follicles. The micro-anatomy was analysed in 119 controls. In cases of traumatic rupture the white pulp showed evidence of stimulation. A pathognomonic histological picture was not found in idiopathic thrombocytopenic purpura. In haemolytic anaemia the pulp cords were engorged by erythrocytes accompanied by a decreased B/T cell ratio in autoimmune haemolytic anaemia and by an increased B/T cell ratio in congenital spherocytosis.     

Clinical Results of Automatic Slope Adaptation in a Dual Sensor VVIR Pacemaker

Manual slope programming in rate adaptive pacemakers can be time consuming. This may become worse with dual sensor devices. The remedy is to let the pacemaker automatically learn the slopes. Fast learning replaces initial manual slope programming. Daily learning is a continuous process to determine and optimize slopes during daily life. Both methods are known for a QT sensing pacemaker. Fast learning is known for other single sensor devices. The aim of this study was to follow daily learning in a QT and activity dual sensor pacemaker, starting with factory slope settings. Six patients were studied for about 8 weeks. The daily learning algorithm appeared to be elective, showing the desired regulation processes. It took 2–5 weeks to reach full rate response.     

Immunohistology of the human spleen: an inventory of the localization of lymphocyte subpopulations

The immunohistochemistry of the cell population of the human spleen was studied. As controls, a strictly defined group of five specimens were used. This study stresses the need for the utmost care in this selection procedure. Using enzyme- and immuno-histochemistry the lymphocyte subpopulations were studied as to their localization in the several specific compartments in the red and white pulp. The findings were compared to those in idiopathic thrombocytopenic purpura, autoimmune haemolytic anaemia and Hodgkin's disease. In the controls a consistent pattern was found. There were specific changes in each of the disease groups consisting mainly of shifts between the compartments.