Relationship between European Mitochondrial Haplogroups and Chronic Renal Allograft Rejection in Patients with Kidney Transplant

Mitochondrial DNA variants may contribute to differences in mitochondrial function, leading to an altered immune system. The aim of this study was to analyze the relationship between mtDNA haplogroups and the development of chronic allograft dysfunction in patients with kidney transplant. A retrospective observational study was carried out on 261 patients who received kidney transplant (114 had stable transplant and 147 patients developed chronic allograft dysfunction). DNA samples were genotyped for 14 mtDNA polymorphisms by using Sequenom''s MassARRAY platform (San Diego, CA, USA). Only European white patients within the N macro-cluster were included. Patients with haplogroups V (odds ratio (OR)=0.32; p=0.037) and J (OR=0.36; p=0.038) showed lower odds for developing CRAD than patients with haplogroup H. After adjusting for the most significant variables, haplogroups V and J tended to statistical significance (p=0.091 and p=0.067 respectively). This is a preliminary study in which mtDNA haplogroups seem to be implicated in susceptibility or protection for developing chronic allograft dysfunction.     

Studies on Several Genetic Hematologic Characteristics of the Mexican Population: IV. The Finding of a Fast Hemoglobin Component (Hemoglobin Mexico) in an Indian Family

The clinical, genetic and electrophoretic characteristics of what is verylikely a new hemoglobin variant, hemoglobin Mexico, are presented. It isclinically silent, transmitted by an autosomal co-dominant gene, and inalkaline pH moves faster than hemoglobin A.

Submitted on January 9, 1963 Accepted on April 21, 1963     

Manifest Fast and Slow Pathway Conduction Patterns and Reentry in a Patient with Dual AV Nodal Physiology

Manifest Fast and Slow AV Nodal Conduction Patterns and Reentry. A 52-year-old woman with paroxysmal supraventricular tachycardias (PST) showed short and long PR intervals during sinus rhythm. Repetitive episodes of PST due to simultaneous anterograde conduction through fast and slow conduction pathways (one P-two QRS) were recorded. A self-limited episode of non-paroxysmal AV nodal reentry with anterograde slow and retrograde fast pathway conduction was initiated by a single atrial premature beat. Each pathway depicted distinct refractory periods, conduction velocities, unidirectional block, and Wenckebach-type block suggesting the possibility of a well-defined anatomical substratum.     

Electrophysiologic Changes and Ventricular Fibrillation in Acute Regional Ischemia in the Porcine Heart: The Concept of Wavelength

Early Electrophysiologic Changes in Acute Ischemia. Introduction: The purpose of this study was to match changes in conduction velocity, refractoriness, and wavelength during acute regional ischemia with initiation of ventricular fibrillation. Methods and Results: In 30 isolated, Langendorff-perfused pig hearts we measured refractory period duration and conduction velocity in ventricular myocardium during the first minutes of regional ischemia in an attempt to determine the minimal changes in these parameters related to the occurrence of ventricular fibrillation (VF). In addition, we wanted to evaluate whether wavelength, i.e., the product of conduction velocity and refractory period, was a useful parameter to predict the occurrence of arrhythmias, as has been shown to be the case for atrial arrhythmias.¹ The refractory period increased significantly after 1 minute of ischemia at basic cycle length and after one and two premature beats. Longitudinal and transverse conduction velocities varied with ischemic time. Compared to the preocclusion value, the longitudinal conduction velocity decreased significantly, but only after 2 minutes of ischemia and at basic cycle length. Wavelength was the least sensitive parameter for ischemia: neither in the longitudinal nor in the transverse direction did it change significantly even during 5 minutes of ischemia. VF was never induced by applying a single premature stimulus within the ischemic area. It occurred in 33% of the occlusions when three successive premature stimuli were delivered from within the ischemic zone, and in 100% when they were applied to the nonischemic myocardium. Whenever fibrillation was induced, it occurred within 3 minutes following coronary occlusions. Wavelength, neither before nor after coronary occlusion, could predict whether VF would occur. The only difference between hearts that fibrillated by stimulation of the ischemic myocardium and those that did not was that, in the first group, the refractory period at the site of stimulation prolonged significantly less than in the no-VF group. Since electrophysiologic changes within the ischemic zone are inhomogeneous,² an attempt was made to measure simultaneously at 52 sites the onset of inhomogeneity by determining the average interval between local depolarization during VF. This so-called VF interval is an index of local refractoriness.³ The coefficient of variation of the VF interval, taken as an index of spatial dispersion in refractoriness, increased significantly 1 minute after occlusion in the border zone and 2 minutes after occlusion in the central ischemic area. Conclusion: In conclusion, wavelength is not a useful parameter to predict the occurrence of VF in hearts with regional ischemia because of the inhomogeneity in refractoriness, which develops within 2 minutes of ischemia. VF occurs when hearts are stimulated from sites with relatively short refractory periods, either within or outside the ischemic zone. (J Cardiovasc Electrophysiol, Vol. 3, pp. 128–140, April 1992)     

Alternating Wenckebach Periods in Acute Inferior Myocardial Infarction: Clinical, Electrocardiographic, and Therapeutic Characterization

We report on twelve patients with alternating Wenckebach periods (AWP) occurring during an acute inferior myocardial infarction (AIMI). There were nine males and three females, with a mean age of 61 years (range, 43 to 75). AWP appeared during the first 48 hours of the AIMI in 10 patients and on the fourth day of hospitalization in two patients. AWP occurred spontaneously in nine patients and following the administration of atropine in the remaining three patients. Mean systolic blood pressure significantly decreased during AWP as compared to the period preceding or following the bradyarrhythmia (93 ± 42 mmHg vs 123 ± 37 mmHg, p < 0.02). Killip functional class was significantly higher during AWP as compared to the period preceding or following the bradyarrhythmia (2.1 ± 1.2 vs 1.5 ± 0.8, p < 0.02). Pacemaker therapy was initiated prophylactically in two patients, because of syncope in six, because of hemodynamic deterioration in two, and for syncope and hemodynamic deterioration in two. Three patients died in cardiogenic shock despite pacemaker therapy. No evidence of right ventricular infarction was seen in the patients.
Atropine administration during AWP significantly increased the sinus rate and significantly decreased the ventricular rates and the systolic blood pressure. In addition, three patients developed long bouts of paroxysmal AV block. Isoproterenol administration improved AV conduction in one patient, caused no change in two patients and induced non-sustained ventricular tachycardia in three patients.
In conclusion, AWP occurring during AIMI is a symptomatic bradyarrhythmia associated with hemodynamic deterioration. Drug therapy for this bradyarrhythmia is usually ineffective and sometimes paradoxical responses are observed. Pacemaker therapy is usually needed to correct symptoms and the worsening hemodynamic status. We recommend prophylactic pacemaker implantation in patients developing AWP during AIMI.     

Hairy pigmented congenital naevocellular naevus in a patient with alopecia universalis

We describe a patient with universal alopecia of 8 years duration, and an alopecia-resistant hairy pigmented congenital naevocellular naevus on the scalp.