Paul A. Young

Cortical projections to the inferior colliculus of the cat

Abstract Cortical projections to the inferior colliculus were studied in the cat by the Nauta and the Fink and Heimer degeneration techniques. The auditory cortex projects to all parts of the ipsilateral inferior colliculus, with the the terminations especially heavy in the external nucleus and the dorsomedial part of the central nucleus. Projections from the somesthetic, visual, and motor areas of the cortex terminate in various parts of the external nucleus and the medial part of the central nucleus. These connections are discussed as a possible inhibitory function to the inferior colliculus and thus influencing the ascending auditory system. The subdivisions of the inferior colliculus are also discussed.

Ultrastructural changes in the cerebrovascular endothelium induced by a diet high in linoleic acid and deficient in vitamin E

Abstract Studies were made on the blood vessels of the brain of chicks which were fed a diet high in linoleic acid and deficient in vitamin E. Electron microscopic observations revealed that ceroidlike dense bodies began to accumulate in some endothelial cells after 1 wk on the diet. By 2 wk, these dense bodies were found to occupy large segments of the endothelial cytoplasm in many blood vessels. The endothelia of capillaries and venules of the cerebellum in addition, were swollen and underwent fragmentation and denudation with focal breakdown of the vascular wall. The pathogenesis of the vascular injury was discussed in the light of lipid peroxidation as a result of excess uptake of unsaturated fatty acid with the absence of vitamin E.

Efferent projections of the lateral dorsal nucleus in the rat

Abstract The present study was undertaken to determine the efferent projections of the lateral dorsal nucleus of the rat thalamus using procedures based on anterograde degeneration as well as anterograde and retrograde axoplasmic transport. Discrete lesions or injections of [3H]leucine were placed at separate anterior and posterior loci in the lateral dorsal nucleus to determine if these portions of the nucleus project to different terminal fields. From both loci, labeled or degenerating axons coursed laterally from the nucleus, passed through the superior thalamic radiation, and entered the caudate-putamen complex. From there, a large number of fibers coursed rostrally in the album cerebri and terminated in layers I and III of anterior cingulate cortical areas 23 and 24. The remaining fibers passed dorsally and entered the posterior cingulate cortex where terminations were observed in areas 29b and 29c. Within area 29b, terminations were arranged parallel to the surface in layers I and III at its border with area 29c. In animals with anteriorly placed lesions or injections, area 29c exhibited input in layers I, III, and IV at the lip of the hemisphere. After injections in the posterior part of the lateral dorsal nucleus, a denser distribution was observed within the same layers at the border of areas 29b and 29c. Projections and areas of termination were also observed from both anterior and posterior lesions or injection sites to the laminae dissecans and externa of the pre- and parasubiculum. These projections were confirmed by retrograde axoplasmic transport of horseradish peroxidase after its injection in the cingulate and subicular cortices. These results indicate that the lateral dorsal nucleus, through its prominent connections with the anterior and posterior parts of the cingulate cortex and subicular region may have significant connections with the limbic system.

Thermography and the sensory dermatome

The basic neuroanatomic and physiologic aspects of the sympathetic outflow to the limbs are reviewed and correlated with the somatic sensory dermatomes. The recent literature is considered. A thermocouple thermometer was used to test 30 normal patients and 87 patients with clinically proven nerve root lesions. Thermographic imaging of the sensory dermatome is not plausible, and thermography is not recommended for clinical documentation of painful conditions of the neck, back, or limbs.

Ultrastructural changes in chick cerebellum induced by vitamin E deficiency

SummaryFocal lesions were induced in the cerebellum by feeding chickens a diet high in unsaturated fats and deficient in vitamin E. Ultrastructurally, the lesions consisted of central and peripheral zones. The central zone was characterized in the cortex and white matter by enlargement of the intercellular space, swelling of astrocytes, vacuolization of oligodendrocytes, ballooning of nerve fibers, degenerative changes in small blood vessels, and extravasation of plasma and blood cells. The peripheral zone was characterized by enlargement of the intercellular space in the white matter, swelling of astrocytes in the cortex, and the accumulation of dark bodies in the endothelium of small blood vessels. The results suggest that this nutritional encephalopathy is caused by alterations in the permeability of the vascular bed due to the dietary stress of unsaturated fatty acids in the absence of vitamin E.

Histological observations on the evolution of nutritional encephalomalacia in chick cerebellum

SummaryA study was made of the histological alterations which occur in the development of nutritional encephalomalacia in the chick cerebellum. 3 categories of chicks were discernible according to severity of symptoms.The earliest changes consisted of focal edema in the folial and medullary white matter. These became progressively more severe and resulted in widespread spongy degeneration. Edema of the Purkinje layer consistently appeared and led to a separation of this layer from the underlying granular layer. Apparent capillary proliferation was noted in all layers and distention of blood vessels finally resulted in hemorrhage and in necrosis of the folia.Clinical signs occasionally occurred without apparent morphological alterations. The edematous process, when noted, was considered to be intracellular, involving glial elements in the white matter and the Golgi epithelial cells (Bergmann astroglia) in the Purkinje layer. The condition results from altered permeability of the cerebellar blood-brain barrier which is selectively affected by the metabolic changes brought about by vitamin E deficiency.ZusammenfassungDie histologischen Veränderungen in der Entwicklung von nutritiver Encephalomalacie im Kleinhirn des Huhnes wurden untersucht. Nach der Schwere der klinischen Symptome wurden 3 Gruppen von Tieren unterschieden.Die frühesten Veränderungen bestanden in Ödemherden im Läppchenmark und Marklager, die progredient an Schwere zunehmen und ausgedehnte spongiöse Degeneration bewirken. Ödem der Purkinje-Zellschicht trat regelmäßig auf und führte zu ihrer Ablösung von der darunterliegenden Körnerschicht. Deutliche Capillarproliferation war in allen Schichten erkennbar. Die Gefäßerweiterung führte schließlich zu Blutungen und Nekrosen in den Läppchen.Klinische Symptome traten gelegentlich ohne manifeste morphologische Läsionen auf. Der ödematöse Prozeß wurde, wenn nachweisbar, als intracellulär aufgefaßt. Er betraf Gliaelemente des Markes und die Golgi Epithelzellen in der Purkinje-Zellschicht (Bergmann Astroglia). Diese Veränderung ist bedingt durch Permeabilitätsveränderungen der cerebellaren Bluthirnschranke, die selektiv betroffen erscheint, wenn der Stoffwechsel durch Vitamin E-Mangel gestört wird.

Association Projections from the Secondary Somatosensory Cortex in the Cat

The autoradiographic study of the association fiber connections of the secondary somatosensory area in the cat confirmed all the connections that were described by Yamaguchi in 1980

Immunophoretic Evaluation of Blood Serum Proteins in Chickens. I. Changing Protein Patterns in Chickens According to Age.

Summary and Conclusions 1. Immuno-phoresis was performed in a series of 42 normal chickens from ages 1 to 210 days. Rabbit serum immunized against normal mature chicken serum was used for antibodies. Bar-bital buffer at pH 8.6, ionic strength 0.1 was used. 2. Identification of fractions was attempted by designating precipitation curves in the chick serum preparation with the names used for curves of known fractions in identical position and of identical shape in human serum preparations made under identical conditions. 3. Significant findings in chicken serum indicate that all fractions are more abundant in neonatal life than at later periods. 4. Prealbumin becomes less abundant after the 12th day of life, and is not detected in the preparations after the 20th day. 5. Precipitation curve in the position of the beta lipoprotein fraction is not observed in preparations after the 8th day of life. 6. Additional fractions of gamma globulin appear in some preparations after the 12th day of life. 7. The findings are significant for comparison with serological protein profiles of chickens on vit E-deficient diets.

The performance of students selected through a special program at St. Louis University School of Medicine.

PURPOSE: To compare the performances of students selected through a special program, the Medical Anatomy Preparatory Program (MAPP), at St. Louis University School of Medicine with those of students admitted at the traditional way. METHOD: The students were members of the classes of 1993-1996 at the St. Louis University School of Medicine (N = 654). Of these, 52 (8%) were MAPP students. The MAPP students and the non-MAPP students were compared on the basis of various test scores and grades obtained from the admission office, the registrars office, and the office of curricular affairs. Means and standard deviations were computed for each group, and the MAPP students and the non-MAPP students were compared using analysis of variance to assess the statistical significance of any differences. RESULTS: The non-MAPP students were significantly better than were the MAPP students in terms of Medical College Admission Test scores, undergraduate gradepoint averages, grades for three major second-year courses, and performances on Steps 1 and 2 of the U.S. Medical Licensing Examination (all p < .001). There was no significant difference between the groups in grades for three major first-year courses or five major third-year courses. None of the MAPP students has been dropped for academic reasons. CONCLUSION: The MAPP program takes medical school applicants who have been rejected because of their preadmission performances, given them the opportunity to show that they can perform at the medical school level by taking the anatomy courses with the regular medical students, and accepts those who are successful. The results suggest that those chosen can satisfactorily complete the requirements for the MD degree.

Immunophoretic Evaluation of Blood Serum Poteins in Chickens. II. Patterns in Vitamin E Deficiency Encephalomalacia.

Summary and Conclusions 1. Twenty-five newly hatched or very young chickens were subjected to a purified diet, deficient in vit E or any synthetic antioxidant and supplemented with 4.8% linoleic acid. If permitted to survive, these chicks developed encephalo-malacia between the 10th and 26th day. Forty-two chicks, fed on a conventional stock laboratory diet, developed normally and were well at the time blood samples were examined. 2. Immunophoresis patterns of blood sera from experimental and normal chickens were obtained. 3. In the experimental sera, an antigen-antibody precipitation curve with the mobility of beta lipoprotein persisted whereas this curve did not persist after the 10th day in normal chickens. This curve was interpreted as due to the presence of an abnormal protein, possibly a denatured beta lipoprotein. 4. The role of possible denaturation of beta lipoproteins in the blood serum in the presence of autoxidation products of linoleic acid in the serum as a possible mechanism for production of vit E deficiency syndromes is discussed.