Chemical models of oxidative phosphorylation

Chemical models for coupling oxidation to phosphorylation are summarized and examined both from the standpoint of organic reaction mechanisms and with respect to their relevance to mitochondria and chloroplasts. In order to accelerate the progress of our research in bioenergetics, it is suggested to focus at least as much attention on structural biochemistry as on phenomenological observations of energy-transducing membranes.     

Statistical methods for the analysis of tumor multiplicity data

The fit of tumor multiplicity data from 93 mouse skin, lung, and liver carcinogenicity experiments to Poisson, negative binomial, and normal distributions was studied. The data were fitted well by the negative binomial distribution. This distribution has two parameters, the mean tumor multiplicity and an exponent determined by the interanimal homogeneity of tumor response. The value of the latter parameter was related to animal strain and the target tissue studied in the carcinogenicity experiments. The null distribution of the two-sample likelihood ratio test based on the negative binomial with common exponent model for tumor multiplicity data was shown by simulation studies to be approximately chi 2 with 1 d.f. Simulation also indicated that the likelihood ratio test has sufficiently better performance when the negative binomial model is valid to make its use more attractive than the more commonly used Wilcoxon test or Student t test. Charts for estimating the number of animals per group that are required to detect specified differences in tumor multiplicities are provided for several commonly used assays.     

Mass spectrometry: application in the exercise sciences

This paper outlines a computerized system for monitoring physiological functions during exercise, using a mass spectrometer for analyzing the concentration of the mixed expired air. Examples are provided illustrating the operation of this system in both research and clinical situations. The most remarkable aspect of the system is its versatility, coupled with its accuracy. While the applications reviewed in this paper are rather narrow, work has been initiated using the mass spectrometer to measure residual lung volumes by the oxygen dilution technique, cardiac output by the CO2 rebreathing technique, and total body density by the helium dilution technique. The application of the mass spectrometer into other areas most certainty will occur in the near future.     

Hematuria and sickle cell disorders

To examine the relationship between gross hematuria and sickle cell disorders, all patients admitted to Grady Memorial Hospital with the diagnosis of a sickle cell disorder during a 14-month period were reviewed. Of 115 such patients, 65% had sickle cell disease and 35% had sickle cell trait. None of the former but seven of the latter group had gross hematuria. Mean age of the seven was 30 years. Comprehensive examinations and laboratory studies showed that all were free of concomitant disease. Physical findings, diagnostic modalities, and treatment were reviewed. Findings suggest that conservative therapy (bed rest, hydration, and diuresis) is usually effective.