Survival of Radiochromium-labeled Platelets in Thrombocytopenias

Platelet survival studies were performed by the radiochromium method in280 patients. Although various types of patients were studied, markedly accelerated platelet destruction was encountered only in those with ITP. Nothrombocytopenic patient was found with accelerated platelet production andchanges in platelet count with therapy reflected corresponding changes insurvival. The use of surface scanning showed that patients with significantsplenic localization were more suitable candidates for splenectomy that thosewithout this localization.

Submitted on December 24, 1962 Accepted on June 21, 1963     

Induction of Abnormal Ventilatory Responses to CO2 and Evaluation of Agents Given to Prevent or Reverse These Responses

Induction of Abnormal Ventilatory Responses to CO2 and Evaluationof Agents Given to Prevent or Reverse These Responses. SCHAPER,M., AND ALARIE, Y. (1988). Fundam. Appl Toxicol 10, 506–516.This study demonstrates how a previously described animal modelcan be utilized to evaluate the effects of multiple aerosols.For the exposures presented in this report, unanesthetized butmildly restrained guinea pigs were used. Airflow (V), tidalvolume (V_T), and respiratory frequency (f) were continuouslymeasured in all animals and their flow-volume (V–V_T) loopswere also obtained. The animals were first exposed to room airand then challenged with a 10% CO2 (in 19% O₂, 71% N₂) mixture.The normal ventilatory response to 10% CO₂ consists of increasesin V, VT, and f. This response is very stable for long periodsof time and is highly reproducible. It is possible, however,to alter the normal CO₂ response by adding an aerosol to theCO₂ mixture. Two types of acute responses can be induced, TypeI and Type II. In this study, histamine and carbamylcholineaerosols were used to induce the Type I response while propranololaerosols were used to induce the Type II response. Serotoninaerosols were used to induce both types of effects. We reportthat the bronchodilator, isoproterenol, reversed the Type Ipulmonary effects where the level of reversal was deoendentupon isoproterenol concentration. The rapid, shallow breathing,characteristic of the Type II response, was not reversed byisoproterenol but could be prevented by blocking the vagus nervewith cocaine. Since no invasive techniques are required andthe same animals can be used repeatedly, combinations of aerosolscan be tested in order to delineate how Type I or Type II abnormalventilatory responses to CO₂ are induced by a wide variety ofairborne chemicals.     

Splenic Pseudocyst Associated with Hypersplenism

A patient with hypersplenism, who was found to have a splenic pseudocyst containing an organized hematoma, is described. There are only two patients with splenic pseudocyst and hypersplenism and an additional two patients with splenic cysts and hypersplenism reported in the world literature. The hypersplenism associated with splenic cysts and pseudocysts is explained on the basis of an expansion of the plasma volume and the total blood volume, an increased destruction of red blood cells and a pooling of blood in the enlarged spleen. The combined use of ultrasonography and computerized tomography has increased the accuracy of noninvasive diagnosis and made more invasive examinations unnecessary. When the ultrasound is technically unsuccessful or when it shows a mixed echo pattern, one should resort to computerized tomography with which it is possible, almost invariably, to differentiate between cysts and neoplasms.     

The Effect of Saline Iontophoresis on Skin Integrity in Human Volunteers: I. Methodology and Reproducibility

This study, conducted in 36 human volunteers, was an evaluationof the effects of saline iontophoresis on skin temperature,irritation, and barrier function. The major objectives wereto assess the effects of low-level ionic currents, to validatethe proposed methodology of assessment, and to establish reproducibilityin repeated saline iontophoresis applications. This was thefirst of a multistage study designed to assess the safety of24-hr saline iontophoresis episodes at selected currents andcurrent densities. Since an iontophoresis patch challenges theskin harrier both by occluding the skin surface and by passingionic current through the skin, the experimental protocol wasdesigned to permit measurement of the contribution of each ofthese processes to the overall response. In this first stagewe investigated the effect of 10 min of current delivery, at0.1 mA/cm² on a 1-cm² area patch and 0.2 mA/cm² on a 6.5-cm²area patch compared to unpowered control patches. Twelve subjectswere tested under each condition on two separate occasions toexamine reproducibility of the response variable measurements.A further 12 subjects were tested once under the 0.2 mA/cm 6.5-cm2condition. Skin irritation was evaluated via repeated measurementsof transepidermal water loss, capacitance, skin temperature,skin color, and a visual scoring system, before the iontophoresisepisode and after patch removal. No damage to skin harrier functionin terms of skin-water loss or skin-water content was detected.Slight, subclinical, short-lasting erythema was observed forboth conditions. Assessment of correlation coefficients showedhighly statistically significant indications of reproducibilityfor all five response variables measured. The experimental design,in combination with a repeated measures analysis, provided clearseparation of the occlusion and ionic current components ofthe iontophoretic patch challenge. Further, the repeated measuresanalysis gave a highly sensitive assessment of skin irritationand resolution after patch removal. We conclude that the experimentalmethodology is appropriate for assessing possible changes inskin integrity resulting from saline iontophoresis under similaroperating conditions for longer durations and for other skinchallenges from which a subclinical response is expected.     

Right Ventricular Dysplasia: A Report of 24 Adult Cases

Right ventricular dysplasia is characterized by an abnormality in the development of part of the right ventricular musculature. Patients with right ventricular dysplasia may present with ventricular tachycardia, suprgventricular arrhythmias, right-heart failure or asymptomatic cardlomegaly. Twenty-two adult patients with right ventricular dysplasia who had recurrent ventricular tachycardia were seen during a 7-year period. The male/female ratio was 2.7:1. The mean age at the time of hospitalization was 39 years. All but one of the patients had ventricular tachycardia of a left bundle branch block configuration. With few exceptions, the T waves were inverted over the right precordial leads. The heart was usually enlarged and the pulmonary vasculaturc was usually normal. In six patients who had two-dimensional echocardiograms, all showed increased right ventricular diastolic dimensions. All patients had right ventricular angiography; the diagnosis of right ventricular dysplasia was substantiated during surgery in 12 patients and at autopsy in another. Two other patients who did not have arrhythmias had right ventricular dysplasia diagnosed by right- and left-heart angiography. Our unique experience, when combined with a literature review of 34 adult cases, permits a composite clinical profile of this condition in the adult.     

Initial Experience with the High-Density Mesh Ablation Catheter for Pulmonary Vein Isolation

Background: Pulmonary vein isolation (PVI) is usually performed with multiple point-by-point radiofrequency ablation with a second multielectrode circular mapping catheter to validate isolation. We evaluated a 30-mm high-density mesh electrode (HDMA) for mapping and PVI in patients with recurrent atrial fibrillation (AF).
Methods: In 13 patients (validation group) up to three pulmonary veins (PVs) were targeted with the HDMA. A circular mapping catheter was used to validate PVI. PVI was completed with a CARTO-guided approach (Biosense Webster, Diamond Bar, CA, USA) followed by a voltage remap. In 11 patients (feasibility group) the HDMA catheter was evaluated as a stand-alone mapping and ablation tool.
Results: The diagnostic accuracy of the HDMA catheter to evaluate PVI was 100%. The encircled low-voltage area (<0.15 mV) after HDMA-guided PVI was smaller compared to CARTO-guided PVI. In the feasibility group 76% of the PVs could be isolated. Complete isolation of all PVs was feasible in five patients (45%) with a mean procedure and fluoroscopy time of respectively 180 ± 39 minutes and 40 ± 14 minutes. After 1 year 64% of the patients were free of symptomatic AF.
Conclusions: The HDMA electrode is a reliable mapping tool to validate PVI. The majority of PVs can be isolated, but on a patient basis touch-up ablations are necessary in more than 50% of the cases. Therefore, modifications in catheter design are required. The small area of voltage abatement points to an ostial left atrium-pulmonary vein disconnection. Initial clinical results in a small number of patients are promising.