Myospherulosis

A review of the historical development of the understanding of the pathogenesis of myospherulosis is presented. An illustrative case report is reviewed. The role played by petrolatum-based anti-biotic ointments in the development of myospherulosis is emphasized.     

Wenckebach Periods in Sinoatrial Block: Experimental and Clinical Evidence

The reality of sinoatrial Wenckebach periods (WP) has been suggested, but not proven, in the literature. We report experimental and clinical data showing WP in sinoatrial blocks. Experimental sinoatrial blocks were induced by superfusion of bepridil (10(-5) M) in 15 preparations of isolated rabbit right atria. Different types of block were observed, including Blumberger I block, i.e., sinoatrial WP. The recordings showed that the typical pattern of Blumberger type IA block and sinoatrial WP may be due to transient acceleration of the sinus rate, without change in the increment. We also observed sinoatrial WP in a 72-year-old patient on direct recordings of the sinus node (SN) electrical activity. In this case, transient acceleration of the sinus rate also seemed to be involved in the genesis of sinoatrial WP. Analysis of these clinical and experimental data showed similarities that may explain the mechanism of the WP. Usually type IA Blumberger block is said to involve a decrease in the sinoatrial increment to explain the atrial sequence (decrease in PP interval followed by a pause shorter than twice the value of the preceding cycle, then a cycle longer than the one preceding the pause). In fact, this pattern can be observed when the acceleration of the higher structure, the SN, induces block within the lower structure, i.e., the atrium.     

Scattered Radiation Doses during Cardiac Studies using a U-arm type Fluoroscopy system

With the advent of image intensifier systems incorporating a U-arm with parallelogram support, a greater awareness of scattered radiation levels is needed, in particular to cardiologists. Depending on the projection, the cardiologist can now be subjected to scatter from the primary side of the patient, giving rise to much higher leyels of scattered radiation. Doses to cardiologists were measured for typical cardiac studies on such an image intensifier system. Doses to the eyes and thyroid were below the limits recommended by the ICRP, but if the principle of AJLARA. is to be adhered to consideration needs to be given to a secondary barrier, in addition to the lead apron, to provide protection to the eyes and thyroid of the cardiologist.     

Prevalence of Babesia antibody in a selected blood donor population

Human babesiosis, a parasitic disease transmitted by the tick, Ixodes dammini, was confined previously to limited areas of the northeastern United States. It is a rare but potentially life-threatening complication of transfusion. Red cells and platelets prepared from asymptomatic donors have been implicated in transfusion-transmitted cases. More cases of babesiosis are being reported as the range of the vector expands in the United States. Blood donors from an endemic area were tested for antibody to Babesia microti during the summer. Only 3.7 percent of the 779 donors were seropositive, compared with 4.7 percent (p greater than 0.05) of donors from a nonendemic area. An epidemiologic survey of seropositive and matched seronegative controls demonstrated no significant differences that would assist in screening donors.     

Three-phase radionuclide bone imaging in sports medicine

Three-phase radionuclide bone (TPB) imaging was performed on 238 patients with sports-related injuries. A wide variety of lesions was encountered, but the most frequent lesions seen were stress fractures of the lower part of the leg at the junction of the middle and distal thirds of the posterior tibial cortex (42 of 79 lesions). There were no differences in the type, location, or distribution of lesions between males and females or between competitive and noncompetitive athletes. In 110 cases, bone stress lesions were often diagnosed when radiographs were normal, whereas subacute or chronic soft-tissue abnormalities had few specific scintigraphic features. TPB imaging provides significant early diagnostic information about bone stress lesions. Normal examination results (53 cases) exclude underlying osseous pathologic conditions.