An analysis of the knowledge base of practicing internists as measured by the 1980 recertification examination

The performance of practicing internists on the American Board of Internal Medicine's 1980 Recertification Examination was examined in two studies. In the first study, a psychometric common-item equating technique was used to compare the performance of 1980 recertification candidates with that of 1979 certification candidates. Results showed that the knowledge base of practicing internists was similar to that of residents completing training. The second study analyzed the performance of 1980 recertification candidates to determine whether being certified or having an interest in a subspecialty affects a physician's performance on items in that area. The results showed that subspecialists do significantly better than general internists on items pertaining to their area of specialization. Similar outcomes were found for internists with a special interest in a subspecialty area. These findings establish the importance of continued periodic evaluation and support the development of an evaluation tool tailored to the physician's area of concentration.     

Immunocytochemical method to identify myelin basic protein in oligodendroglia and myelin sheaths of the human nervous system

To study the distribution of basic protein (BP) and other myelin constituents immunocytochemically in human nervous tissue, we modified the unlabeled antibody enzyme (peroxidase-antiperoxidase) method. The technique is described here. Because the availability of unfixed tissue from human central nervous system is limited, we tested the method on blocks that had been fixed in formalin and embedded in paraffin, fixed and stored in 4% formalin, or frozen at autopsy and stored. We obtained the best results with paraffin blocks. BP antiserum stained oligodendroglia and myelin sheaths in the developing human nervous system. In the adult, myelin sheaths were well stained. Also, abnormalities associated with myelin breakdown could be identified in multiple sclerosis lesions. The results suggest that this method will be useful in studying the cellular distribution of myelin components in human demyelinating diseases.     

脑益嗪对实验性脑血栓形成及血小板聚集的抑制作用

本文报道脑益嗪对大鼠实验性脑血栓形成及兔血小板聚集的抑制作用。经大鼠颈动脉顺行注射复合血栓诱导剂造成脑血栓模型,测定伊文思兰通过血脑屏障渗入脑实质的量以反映脑血栓的严重程度。结果表明脑益嗪(67 mg/kg,灌胃)有抗脑血栓形成的作用。半体内实验表明脑益嗪(34 mg/kg,灌胃)可抑制兔血小板聚集。     

Anatomical asymmetry of the cerebral hemispheres of the cat brain.

The fissure patterns of 39 cat brains were examined and each hemisphere was classified according to the scheme of Otsuka and Hassier. Of the 33 brains for which there was no ambiguity of classification for either hemisphere, 45 percent were asymmetrical. Included among these asymmetrical brains was that of a newborn kitten. As the asymmetry is focussed predominantly in the region of the visual cortex, it is suggested that this may form the substrate of the functional asymmetry in visual discrimination performance previously demonstrated in cats.     

A method for the assay of inflammatory mediators in follicular casts.

A method is presented whereby inflammatory mediators may be detected and quantified in individual follicular casts. Lysozyme, lactoferrin, IgG, IgM, C3 and material reacting with antiserum to polymorphonuclear leukocytes (PMN) were assayed by functional and immunologic methods. By these techniques, lysozyme, IgG and anti-PMN reactive material were detected in clinically uninflamed follicular casts from acne subjects.     

Modification of paradoxical sleep following transections of the reticular formation at the pontomedullary junction

A retractable wire knife was employed to transect the reticular formation at the pontomedullary junction in order to assess the respective importance of pontine and medullary reticular neurons and their pathways in paradoxical sleep. Thirteen cats were implanted with a standard array of electrodes for polygraphic recording of sleep-wakefulness states during 3 days in baseline condition and during 21 days after transections. Average electroencephalographic (EEG) amplitude, average electromyographic (EMG) amplitude, and ponto-geniculo-occipital (PGO) spike rate were measured per 1-min epoch for each day. A trivariate computer graphics display of 1 day's data revealed three major clusters of points that corresponded to wakefulness, slow wave sleep, and paradoxical sleep in baseline. (a) After transections through the entire reticular formation at the pontomedullary junction, paradoxical sleep was no longer evident in the trivariate computer graphics or polygraphic record, either by the presence of a high PGO spike rate or by that of muscle atonia in association with a low-amplitude EEG. These results indicated that the reticular fibers that pass through the pontomedullary junction and interconnect the pontine tegmentum and the medullary reticular formation are necessary for generating the cluster of electrographic variables that normally characterizes paradoxical sleep. (b) After transections through the dorsal half of the reticular formation, paradoxical sleep was still evident, though with a reduced PGO spike rate, and muscle atonia was normal. These results indicated that the descending noradrenaline locus coeruleus fibers and the "longitudinal catecholamine bundle," which course through the dorsal tegmentum, are not necessary for the generation of muscle atonia or the state of paradoxical sleep. (c) After transections through the ventral half of the reticular formation, paradoxical sleep was still apparent by the association of a moderate, though reduced, rate of PGO spiking in association with low-amplitude EEG activity and a high-amplitude EMG, indicating a loss of muscle atonia. The duration of the PS episodes, however, was greatly reduced. These results indicated that the descending "tegmentoreticular" and ascending reticulotegmental pathways, which course ventrally through the pontomedullary junction and interconnect the dorsolateral pontine tegmentum and the ventromedial medullary reticular formation, are essential for the muscle atonia of paradoxical sleep and important for the normal cyclic generation and maintenance of the state of paradoxical sleep.