The cyclic lipopeptide micafungin induces rupture of isolated mitochondria by reprograming the mitochondrial inner membrane anion channel

The antifungal activity of the drug micafungin, a cyclic lipopeptide that interacts with membrane proteins, may involve inhibition of fungal mitochondria. In humans, mitochondria are spared by the inability of micafungin to cross the cytoplasmic membrane. Using isolated mitochondria, we find that micafungin initiates the uptake of salts, causing rapid swelling and rupture of mitochondria with release of cytochrome c. The inner membrane anion channel (IMAC) is altered by micafungin to transfer both cations and anions. We propose that binding of anionic micafungin to IMAC attracts cations into the ion pore for the rapid transfer of ion pairs.

Developing models for pediatric residency training in managed care settings

The preparation of pediatric residents to function optimally in managed care environments challenges educators to create a new set of educational objectives and competencies and to incorporate these into curricula that are already full. Many of the skills needed to practice managed care are those that have been required for the practice of pediatrics in any setting. Nevertheless, the emergence of managed care requires the identification of new knowledge to be acquired and new skills and attitudes to be incorporated into daily practice. These competencies can be identified most thoroughly through collaboration among physicians, educators, and leaders of managed care organizations. This joint effort should also serve to establish a foundation on which collaborative, mutually beneficial learning environments can be created. The development of curricula that provide the opportunities needed to attain managed care proficiencies requires an individualized approach for each program that takes into account the degree of managed care penetration in each training environment. Programs in which a managed care approach to patient care predominates will be able to promote most easily their trainees' incorporation of these principles into routine practice. Those with less regular exposure will be forced either to promote managed care principles in an environment in which they may not be accepted or practiced, or to join in partnership with managed care organizations (MCOs) to train residents. Regardless of the setting, evaluation methodologies must be developed to ensure that each of the core competencies has been learned, can be applied to clinical situations, and is retained throughout the training period. These efforts require the development of faculty who understand and can model a managed care approach to patient management. The ongoing evolution of managed care systems encourages the development of new, creative strategies to train faculty, who may find themselves learning about this emerging environment at the same time as are their trainees.

Electrocardiographic findings in children with Lyme disease

The incidence of cardiac involvement in Lyme disease (LD) has been estimated to be 4 to 10% in adults, with conduction and rhythm disturbances noted most frequently. To assess the frequency of electrocardiographic abnormalities in children with LD, we prospectively performed 12-lead electrocardiograms in 32 randomly selected children presenting with LD between May and September 1989. No patient had symptoms of cardiac involvement. Using defined diagnostic criteria, combining symptoms, signs, serology, and residence in or travel to an endemic area, 14 patients were classified as having definite LD and 10 were categorized as probable. The incidence of electrocardiographic abnormalities in the definite group was 29% (4/14), including two patients with 1 degree atrioventricular block, one with left axis deviation, and one with ventricular ectopy. Thirty percent (3/10) of the probable group had abnormal ECGs, including one with ST-T wave abnormalities, one with prominent sinus arrhythmia, sinus bradycardia, and wandering atrial pacemaker, and one with ectopic atrial bradycardia. No patient required cardiac therapy. The incidence of abnormal ECG findings in this group of children with either probable or definite LD was thus 29%, with 1 degree atrioventricular block noted most frequently. When the diagnosis of LD is highly suspected, an electrocardiogram may be a useful screening test for cardiac involvement.