Temperature changes in chicken embryos exposed to a continuous-wave 1.25 GHz radiofrequency electromagnetic field.

A total of 550 fertile chicken eggs (White Leghorn) were exposed to a radiofrequency (RF) electromagnetic field of 1.25 GHz (continuous wave) at six different power flux densities in the range of 9.0-0.75 mW/cm(2). The eggs were exposed either continuously throughout the whole 21 days of incubation (long-term exposure) or in a short-term exposure (1-2 h/day). The temperatures of the embryonic tissue and the amniotic fluid, respectively, were measured with inserted temperature probes. This study was designed to investigate the relationship between exposure and temperature changes in exposed tissues, without considering biological and medical effects. This knowledge is of general interest for studies of nonthermic teratological or embryo-lethal effects of exposure to electromagnetic fields (EMFs). Throughout the entire 21 days of embryonic development, the mean temperature increases in the eggs during the exposure were found to be up to 0.25 degrees C for a power flux density of 1.25 mW/cm(2) and increased to 2.3 degrees C for 9.0 mW/cm(2). The corresponding maximum whole-body SARs for the embryos over the 21 days of embryonic development were 1.45 and 10.44 W/kg, respectively. At 0.75 mW/cm(2) (0.87 W/kg) the extent of the RF-field induced hyperthermia was within the measurement accuracy (+/-0.1 degrees C) of the temperature probes used in the tests. The field-induced temperature increase was greatest in the first week of incubation and was less pronounced in the last (third) week before hatching. In both the short- and the long-term exposures, the temperature of the exposed tissue and the amniotic fluid, respectively, reached its maximum (asymptotic) approximately 40-50 min after the RF field was switched on. After the field was switched off, the temperature inside the exposed eggs returned to its initial value within 40-50 min.

Influence of a radiofrequency electromagnetic field on cardiovascular and hormonal parameters of the autonomic nervous system in healthy individuals.

The potential health risks of radiofrequency electromagnetic fields (EMFs) emitted by mobile phones are of considerable public interest. The present study investigated the hypothesis, based on the results of our previous study, that exposure to EMFs can increase sympathetic vasoconstrictor activity. Forty healthy young males and females underwent a single-blind, placebo-controlled protocol once on each of two different days. Each investigation included successive periods of placebo and EMF exposure, given in a randomized order. The exposure was implemented by a GSM-like signal (900 MHz, pulsed with 217 Hz, 2 W) using a mobile phone mounted on the right-hand side of the head in a typical telephoning position. Each period of placebo exposure and of EMF exposure consisted of 20 min of supine rest, 10 min of 70 degrees upright tilt on a tilt table, and another 20 min of supine rest. Blood pressure, heart rate and cutaneous capillary perfusion were measured continuously. In addition, serum levels of norepinephrine, epinephrine, cortisol and endothelin were analyzed in venous blood samples taken every 10 min. Similar to the previous study, systolic and diastolic blood pressure each showed slow, continuous, statistically significant increases of about 5 mmHg during the course of the protocol. All other parameters either decreased in parallel or remained constant. However, analysis of variance showed that the changes in blood pressure and in all other parameters were independent of the EMF exposure. These findings do not support the assumption of a nonthermal influence of EMFs emitted by mobile phones on the cardiovascular autonomic nervous system in healthy humans.

Integrating osteopathic training into family practice residencies.

BACKGROUND AND OBJECTIVES: Since the mid-1980s, the number of osteopathic graduates has increased, and the number of osteopathic hospitals has decreased. This has led to an increasing number of osteopathic students seeking training in Accreditation Council for Graduate Medical Education (ACGME) family practice residency programs. In response to these developments and to a declining pool of allopathic applicants in the early 1990s, at least 35 ACGME programs have completed the American Osteopathic Association (AOA) accreditation process as approved internship sites. This article describes 1) the rationale for becoming accredited, 2) the AOA accreditation process, 3) a model osteopathic curriculum, 4) potential difficulties, 5) issues to consider in approaching a decision to become AOA accredited, and 6) future trends in osteopathic graduate medical education.

Diagnostic criteria and the management of dystocia.

Cephalopelvic disproportion has been identified as making an important contribution to the rising cesarean birth rate. O'Driscoll and colleagues in Dublin, Ireland, have suggested replacement of cephalopelvic disproportion by the term dystocia for failure of labor to progress and have defined two major subcategories: (1) true cephalopelvic disproportion, and (2) inefficient uterine action. A chart audit of reported indications for cesarean birth in a family practice residency population was done, and patients were classified using the O'Driscoll et al diagnostic criteria for dystocia. When reclassified, the percentage of cesarean births in this population for true cephalopelvic disproportion did not differ significantly from that reported from Dublin (6.1 as compared with 8.8), while the percentage done for inefficient uterine action was significantly greater (35.4 as compared with 4.2). This finding suggests there is a set of labors amenable to a management strategy that could result in a decrease in the cesarean birth rates if efficient uterine action is assured with adequate use of oxytocin.