Specific proteolysis regulates fusion between endocytic compartments in Xenopus oocytes.

We examined the role of proteolytic ligand modification in endosomal targeting using vitellogenin (VTG) uptake by Xenopus oocytes as a model system. Non-cleavable VTG is internalized, but does not appear in yolk platelets. We identified two inhibitors of VTG processing into the yolk proteins: the ionophore monensin and pepstatin A, a specific inhibitor of cathepsin D. Pepstatin neither affected ligand binding and internalization, nor inhibited the degradation of nonspecifically incorporated proteins, whereas monensin inhibited all of these processes. Inhibiting VTG processing prevented its deposition into yolk platelets by strongly interfering with endosome-yolk platelet fusion. Monensin treatment resulted in morphologically abnormal endosomes, while pepstatin only inhibited VTG cleavage and the subsequent fusion of endosomes with yolk platelets. Since VTG cleavage is initiated prior to its deposition in platelets, we postulate that ligand proteolysis could be necessary for normal endosomal targeting.

Variations in minimum licensing age and fatal motor vehicle crashes.

The effect of differences in the legal minimum licensing age on fatal motor vehicle crashes was studied in New Jersey (age 17), Massachusetts (age 16 1/2), and Connecticut (age 16). New Jersey's 17-year-old licensing law was associated with greatly reduced fatal crash involvement. It is estimated that 65 to 85 per cent reductions in 16 year-old-driver fatal crash involvement can be expected if the licensing age is increased from 16 to 17 without increasing fatal crash rates at older ages.

Passenger car size and driver seat belt use.

The National Highway Traffic Safety Administration (NHTSA) claims, on the basis of survey results, that seat belt use in small cars is twice as high as in large cars. The agency interprets this as being due in part to perceptions of higher risk by small car occupants. In fact, little is known about the factors motivating belt use, including whether risk perception is important. A reanalysis of the NHTSA data indicates that most of the differences in belt use by car size can be explained by higher use in imported cars, and by geographical differences in belt use in domestic cars.

Nonverbal components of the interpretive process in psychoanalytic psychotherapy.

Viewing traditional psychoanalytic concepts from a new perspective of kinetics and proxemics gives added insight and freshness. A thumb-nail sketch of the new sciences is drawn. These sciences of nonverbal behavior have been far too neglected by clinicians. There is historic precedent for making them part-and-parcel of classical psychoanalysis.

Modalities of psychotherapy with the elderly.

Emphasized is the view that geriatric psychotherapy can be effectively administered only with knowledge of the biology, psychology, and sociology of old age. The concepts of transference, countertransference, interpretation, conflict and defense mechanisms are crucial for understanding the various treatment modalities. Five intervention patterns are offered for the therapeutic approaches, i.e., interpretation, suggestion, reinforcement, confrontation, and clarification. The different modalities of geriatric psychotherapy may be viewed as variations of different clusters of these interventions, e.g., psychoanalysis makes most use of interpretation whereas group therapy makes most use of confrontation and clarification. For the psychologic treatment of disorders in late life, there are five basic modalities and one adjunct. The basic psychotherapies are classified as psychoanalytic, supportive, group, family, and behavioral; the adjunct is psychopharmacologic treatment, which is not a substitute for effective psychotherapy. Much semantic confusion has centered around this adjunctive treatment. Conceptual confusions about the meaning of the word "cure" are discussed.