Prenatal myocardial infarction suspected by fetal echocardiography

Myocardial infarction is rare in the newborn period. We describe a case in which myocardial infarction was suspected at 25 weeks of gestation by fetal echocardiography. There was an aneurysm of the left ventricular apex with paradoxical motion and bulging of the left ventricular free wall during systole. The diagnosis was confirmed by postnatal electrocardiogram, vectorcardiogram, and thallium myocardial perfusion imaging.     

Potential for oxytetracycline administration by three routes to cause milk residues in lactating cows, as detected by radioimmunoassay (Charm II) and high-performance liquid chromatography test methods

Milk antimicrobial residues are a serious concern for the dairy industry. Residues of the tetracycline family of antimicrobials have been reported in market milk by investigators, using radioimmunoassay and microbial receptor technology (hereafter referred to as the Charm II test). In response to these reports, an investigation was conducted to determine the potential of 3 extra-label routes of oxytetracycline (OTC) administration to cause milk residues above the Food and Drug Administration safe value of 30 parts per billion (ppb). Lactating Holstein cows were administered OTC once by use of 1 of 3 routes: IV at 16.5 mg/kg of body weight (n = 6); IM at 11 mg/kg (n = 6); and intrauterine (IU) at 2 g in 500 ml of saline solution/cow (n = 6). Duplicate milk samples were collected at the milking prior to drug administration and for the next 13 milkings at 12-hour intervals. Concentrations of OTC in milk samples were analyzed by use of the Charm II tes for tetracyclines (limit of OTC detection, approx 5 ppb) and were compared with concentrations determined by use of a high-performance liquid chromatography (HPLC) method (lower limit of OTC quantitation, approx 2 ppb). The potential for milk OTC residues above the Food and Drug Administration safe value of 30 ppb after treatment was considerably greater for the IV and IM routes, compared with the IU route.(ABSTRACT TRUNCATED AT 250 WORDS)     

Multi-Wire Proportional Counters for Low-Energy Particles

We have constructed multi-wire proportional-counter arrays in which only every second wire operates as an anode, the others being held at the cathode potential, and have investigated their response to a particles. The variation of the sensitivity and amplification with voltage and with different geometrical arrangements is described.     

The hemodynamic effects of induced supraventricular tachycardia in man

The circulatory effects of supraventricular tachycardia (SVT) were studied in eight patients who reported disabling symptoms during paroxysms of the arrhythmia. Supraventricular tachycardia was induced in each patient by rapid atrial pacing or with atrial premature stimuli. Hemodynamic parameters in sinus rhythm and following the initiation of SVT were recorded and compared. The following mean values were observed in sinus rhythm (SR) and SVT. Heart rate (beats/min): SR 79, SVT 183; P-R interval (msec): during SR, 154; during SVT, 256; ratio of mean P-R intervals to mean R-R cycl lengths: SR 20%, SVT 76%; brachial artery pressures (mmHg): SR 141, SVT 99; cardiac index (L/min/m2): SR 3.6, SVT 2.2; pulmonary artery pressures (mmHg): SR 18/7, SVT 26/15; peak right atrial pressures (mm Hg): SR 4, SVT 17. Large waves appeared in the right atrium during SVT due to atrial contraction against closed tricuspid valves. Pulsus alternans were observed in each case during SVT. Despite the presence of chest pain during SVT, the coronary arteries were normally patent in four patients who underwent coronary arteriography.     

On the Independence of Magnetic and Electric Body Surface Recordings

Recent papers have shown that the ECG depends on the flow sources of the impressed field in the heart while the MCG is a function of its vortex source distribution. It has consequently been suggested that body surface electric and magnetic recordings yield completely independent information about the physiological generators. Such independence would be of enormous significance wherever present diagnostic procedures rely heavily on the ECG or EEG. This paper points out that the independence of the flow and vortex sources is only a mathematical possibility. It demonstrates that two important physical constraints are operating which require the flow and vortex sources to be, in effect, one-to-one with each other. Consequently, the electric and magnetic fields arising from excitable tissue in an assumed homogeneous volume conductor are fundamentally interdependent.     

Interplay of design parameters and fabrication conditions on the performance of monomode fibers made by MCVD

An apparently undocumented loss mechanism in monomode fibers with germanium doped cores is demonstrated. This loss increases as the fiber drawing temperature and/or the germanium concentration increases. By consideration of this mechanism in the fiber design and fabrication, losses lower than previously reported have been achieved both in fiber with low germanium concentration (0.38 dB/km at 1.3 μm) and in higher doped, dispersion shifted fiber (0.37 dB/km at 1.55μm). The constraints on fiber design as a consequence of this loss mechanism are discussed.     

Report on APA's income protection plan: Announcement of higher weekly benefits and of expanded coverage.

Item notes that APA's income protection plan insures APA members against loss of income during periods of total disability, paying benefits when an insured member is unable to work at his regular occupation because of sickness or accident. The present plan provides payments ranging from $25.00 a week to $100.00 a week during periods that an insured member is prevented from working at his regular job because of sickness or accident. Beginning on May 1, 1959, benefits as high as $150.00 a week will be available on certain plans. These provisions are outlined. (PsycINFO Database Record (c) 2010 APA, all rights reserved)