Karnofsky performance status revisited: reliability, validity, and guidelines

Little research has been conducted documenting the reliability and validity of the Karnofsky Performance Status (KPS) scale, and guidelines based on empirical data do not exist to govern its use. Two hundred ninety-three cancer patients completed a questionnaire that assesses their physical and psychosocial difficulties. Physicians rated patients on the KPS and a subsample of 75 patients was used to evaluate interrater reliability. Analyses were conducted to evaluate the interrater reliability and construct validity of the KPS. The KPS was shown to have good reliability and validity. Detailed examination of the reliability data suggested areas in which physicians err in their judgments. Multiple regression techniques were used to empirically identify seven behaviorally based questions that would be helpful in predicting KPS scores. The seven variables included weight loss, weight gain, reduced energy, difficulty walking, driving, grooming, and working part time. An interview approach with behaviorally based guidelines is presented using these variables to obtain relevant data and make more accurate KPS ratings. With the approach suggested and the guidelines presented, oncologists may train themselves to use the KPS in a standard way, which should increase reliability and validity of the KPS and has implications for patients and research studies that use KPS as a stratifying variable.     

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Relation between sperm count and semen volume, and pregnancies obtained during a twenty-year follow-up period

The clinical fertility of 1077 men investigated with sperm analysis including sperm count and semen volume during the years 1950-52 was studied 20 years later using a questionnaire, replied by 785 (72.9%). There was a significant correlation ( P < 0.01) between sperm count and number of living children, but no relation to abortions and pathological pregnancies. Furthermore, sperm count was correlated ( P < 0.01) to time interval from wish of pregnancy to pregnancy obtained. Of 53 men with sperm count ≤ 5 mill/ml 22.6% obtained living children compared with 52.2–63.1% living children in 730 men with sperm count > 5 mill/ml. Sperm count is concluded to be proper for fertility classification, and sperm count 5 mill/ml is found to be the clinically significant borderline of male infertility. There was no relation between semen volume and pregnancies obtained, however, there was a statistical relation ( P < 0.01) to time interval to pregnancy obtained. Semen volume is concluded not to be suited for fertility classification.     

Remote-controlled device for sampling arterial blood in unrestrained animals

A device is described that allows remote-controlled sampling of arterial blood in unrestrained animals. An artery and a vein are dissected in local anesthesia and connected by a plastic catheter, the sampling catheter. The flow of arterial blood in this artificial shunt can be blocked by kinking the sampling catheter by a remote-controlled device. The blood thus trapped in the sampling catheter, of 0.45 ml volume is analyzed for PO2, PCO2, and pH using electrodes. The technique has been used in ducks and hens but can be applied to other vertebrate classes and to species of smaller body size.     

Monosynaptic activation of a direct reticulo-spinal pathway by the dentate nucleus

Experiments were performed to test the hypothesis that the output of the dentate nucleus can affect the excitability of spinal neurons via the reticular formation. In the first group of studies, the response of neurons in the medial reticular formation to stimulation of the dentate nucleus was investigated. In the second set of experiments, stimuli were applied in the same region of the medial reticular formation in order to determine whether neurons in the dentate nucleus could be antidromically activated from this part of the brainstem. The results indicate that the output from the dentate nucleus monosynaptically activates medial reticular neurons which project to the spinal cord. This finding, together with the observation that stimulation of the medial reticular formation can antidromically activate neurons in the dentate nucleus, demonstrates that there is an anatomical substrate by which the dentate nucleus can affect the excitability of spinal neurons via a rapidly conducting reticulospinal pathway.