Co-chaperones Bag-1, Hop and Hsp40 regulate Hsc70 and Hsp90 interactions with wild-type or mutant p53.

Using highly purified proteins, we have identified intermediate reactions that lead to the assembly of molecular chaperone complexes with wild-type or mutant p53R175H protein. Hsp90 possesses higher affinity for wild-type p53 than for the conformational mutant p53R175H. The presence of Hsp90 in a complex with wild-type p53 inhibits the binding of Hsp40 and Hsc70 to p53, consequently preventing the formation of wild-type p53-multiple chaperone complexes. The conformational mutant p53R175H can form a stable heterocomplex with Hsp90 only in the presence of Hsc70, Hsp40, Hop and ATP. The anti-apoptotic factor Bag-1 can dissociate Hsp90 from a pre- assembled complex wild-type p53 protein, but it cannot dissociate a pre-assembled p53R175H-Hsp40- Hsc70-Hop-Hsp90 heterocomplex. The results presented here provide possible molecular mechanisms that can help to explain the observed in vivo role of molecular chaperones in the stabilization and cellular localization of wild-type and mutant p53 protein.

Oxitropium bromide, a new anticholinergic bronchodilator.

Oxitropium bromide (OB) is a quaternary ammonium congener of hyoscine with anticholinergic properties. We studied its bronchodilating properties in 14 patients with chronic obstructive lung disease without features of asthma in whom theophylline and other bronchodilators were withheld. Five doses of OB(20, 40, 100, 200, and 400 micrograms) as well as 150 micrograms of isoproterenol (ISO) and placebo were administered by metered-dose inhaler on separate occasions in a double-blind fashion. Pulmonary function (flow volume loops and airways resistance), blood pressure, and pulse rate were measured at baseline and periodically for eight hours after drug administration. Onset of bronchodilator effect was within five minutes for OB (P less than .025). Duration of action of OB was at least eight hours (P less than .025). The dose response characteristics of OB were examined by correlating the log dose with the areas under the time-FEV1 curve (r = .97, P less than .01), the time-forced vital capacity curve (r = .98, P less than .01), and the time-SGAW curve (r = .83, P less than 0.1). For FEV1, doses of 40 to 400 micrograms were significantly better than placebo and 100 to 400 micrograms were better than ISO (P less than .01). For forced vital capacity, all doses of OB were better than placebo (P less than .05). For SGAW, the response to the 100- and 400-micrograms doses were significantly better than placebo and isoproterenol (P less than .05). There were no significant effects of OB on pulse, blood pressure, or electrocardiogram. No side effects were noted from the use of OB.(ABSTRACT TRUNCATED AT 250 WORDS)

On the question of pre-existing personality differences between users and nonusers of drugs.

This study represents a beginning attempt to investigate the possible existence of predrug usage, personality differences between users and nonusers of drugs. Ss were male college students: 30 heavy marijuana (multiple drug) users, 30 light marijuana users, and 30 nonusers were compared on the results of the Gordon Personal Profile administered prior to the use of any drugs. Significant differences were found on two of the personality scales on this instrument.