Martin G. Netsky

Bio: Martin G. Netsky is an academic researcher from Wake Forest University. The author has contributed to research in topics: Choroid plexus & Ependyma. The author has an hindex of 22, co-authored 56 publications receiving 1667 citations.

ticles Effect of Neonatal Malnutrition on Developing Cerebrum: I. Microchemical and Histologic Study of Cellular Differentiation in the Rat

Abstract: STUDIES of malnutrition indicate the importance of the "sparing effect": of all organs of the body, the brain is least affected by starvation during growth.1-5This widely accepted but partially correct conclusion is based on observations of rats weaned at 21 postnatal days and then undernourished. In 1917 and 1918, Sugita6,7emphasized that the normal growth of the cerebral cortex of the rat is precocious in relation to the body; the cortex reaches adult width and develops six layers during the first three weeks of life, but the maximal increment of growth of the body occurs between three and seven weeks. Sugita therefore suggested that the effect of undernutrition on the development of cerebral cortex is better studied in suckling rats during the first three postnatal weeks when growth of cortex and cytoplasmic differentiation of neurons is maximal.8 Recent investigations9-11on growth of whole

The Choroid Plexus in Health and Disease

Abstract: This book is James O'Leary's last work, and reflects the many-faceted accomplishment of fine clinical and scientific neurologists. Traditionally, epilepsy always has lain close to the heart of the electrophysiologist and cerebral localizer, for seizure patterns not only reflect the functional neuroanatomy of the brain, but imply something of the mixed stimulation-inhibition of neurological function. O'Leary and Goldring use the story of epilepsy to take us through progressive understandings of the brain and its paroxysmal disease from earliest times to the present, devoting chapters to the development of the neurone doctrine, electrophysiology, localization, the electroencephalogram, and the brain stem reticular core. It also reviews some of the more specific physiologic, anatomic, and pharmacologic abnormalities of the epilepsies. The chemistry of the epilepsies receives short shrift, but that was neither O'Leary's

Differentiation of medulloblastoma: Studies including immunohistochemical localization of glial fibrillary acidic protein

Abstract: ✓ A series of medulloblastomas was studied by light microscopy. The tumors were variable: astrocytic, ependymal, neuronal, and probable oligodendroglial differentiation was present. Features of glioblastoma multiforme occurred in one case. Immunoperoxidase staining for glial fibrillary acidic protein (GFAP), an antigen found only in astrocytes and ependymal cells, revealed astrocytic differentiation in 11 of 13 cases. The two GFAP-negative tumors were histologically undifferentiated. A new classification of medulloblastomas is presented, based on the multiple types of differentiation of these tumors. Neuronal, astrocytic, ependymal, and small-cell types are described. Undifferentiated tumors were more frequent in younger children. The differentiation of medulloblastoma is correlated with recent experimental studies of gliogenesis and neurogenesis. A hypothesis that medulloblastoma is a stem-cell neoplasm is presented, based on these comparative data.

Pragmatics of measuring recognition memory: applications to dementia and amnesia.

Abstract: SUMMARY This article has two purposes. The first is to describe four theoretical models of yesno recognition memory and present their associated measures of discrimination and response bias. These models are then applied to a set of data from normal subjects to determine which pairs of discrimination and bias indices show independence between discrimination and bias. The following models demonstrated independence: a two-highthreshold model, a signal detection model with normal distributions using d' and C (rather than beta), and a signal detection model with logistic distributions and a bias measure analogous to C. Cis defined as the distance of criterion from the intersection of the two underlying distributions. The second purpose is to use the indices from the acceptable models to characterize recognition memory deficits in dementia and amnesia, \bung normal subjects, Alzheimer's disease patients, and parkinsonian dementia patients were tested with picture recognition tasks with repeated study-test trials. Huntington's disease patients, mixed etiology amnesics, and age-matched normals were tested by Butters, Wolfe, Martone, Granholm, and Cermak (1985) using the same paradigm with word stimuli. Demented and amnesic patients produced distinctly different patterns of abnormal memory performance. Both groups of demented patients showed poor discrimination and abnormally liberal response bias for words (Huntington's disease) and pictures (Alzheimer's disease and parkinsonian dementia), whereas the amnesic patients showed the worst discrimination but normal response bias for words. Although both signal detection theory and twohigh-threshold discrimination parameters showed identical results, the bias measure from the two-high-threshold model was more sensitive to change than the bias measure (C) from signal detection theory. Three major points are emphasized. First, any index of recognition memory performance assumes an underlying model. Second, even acceptable models can lead to different conclusions about patterns of learning and forgetting. Third, efforts to characterize and ameliorate abnormal memory should address both discrimination and bias deficits.

Malignant peripheral nerve sheath tumors. A clinicopathologic study of 120 cases.

Abstract: A review was done of 120 cases of malignant peripheral nerve sheath tumor (MPNST) seen during a 71-year period. Of the 120 patients, 52 were males and 68 were females with a mean age at diagnosis of 35.3 years; 12 patients were younger than 20 years. The series included 62 (52%) patients with neurofibromatosis, 13 (11%) with postradiation sarcomas, and 19 (16%) with metaplastic foci. The incidence of MPNST arising in neurofibromatosis was 4.6% in the current series and 0.001% in the general clinic population. Tumors greater than 5 cm and the presence of neurofibromatosis adversely affected the prognosis (P less than 0.05). When both features were present, survival was greatly decreased. Patients with tumor in the extremities did better than those with head or neck lesions. Metaplastic foci or previous radiation at the tumor site did not alter the prognosis. Each tumor was graded 1 to 4 on the basis of cellularity, pleomorphism, mitotic index, and necrosis. No significant correlation was noted between survival and either grade or mitotic rate. Survival was improved when total rather than subtotal resection was done. This was most marked in patients with a small lesion, which may reflect the difficulty in adequately excising large tumors. Adjuvant radiation or chemotherapy did not appear to affect survival. The MPNST is an aggressive uncommon neoplasm, and large tumor size, the presence of neurofibromatosis, and total resection are the most important prognostic indicators.

The Central Nervous System

Abstract: Evolution of Nervous Control from Primitive Organisms to Man A Symposium organized by the Section on Medical Sciences of the American Association for the Advancement of Science, and presented at the New York Meeting on December 29–30, 1956. Edited by Allan D. Bass. Pp. vii + 231. (Washington, D.C.: American Association for the Advancement of Science; London: Bailey Bros. and Swinfen, Ltd., 1959.) 52s.

Epidemiology and etiology of Parkinson’s disease: a review of the evidence

Abstract: The etiology of Parkinson’s disease (PD) is not well understood but likely to involve both genetic and environmental factors. Incidence and prevalence estimates vary to a large extent—at least partly due to methodological differences between studies—but are consistently higher in men than in women. Several genes that cause familial as well as sporadic PD have been identified and familial aggregation studies support a genetic component. Despite a vast literature on lifestyle and environmental possible risk or protection factors, consistent findings are few. There is compelling evidence for protective effects of smoking and coffee, but the biologic mechanisms for these possibly causal relations are poorly understood. Uric acid also seems to be associated with lower PD risk. Evidence that one or several pesticides increase PD risk is suggestive but further research is needed to identify specific compounds that may play a causal role. Evidence is limited on the role of metals, other chemicals and magnetic fields. Important methodological limitations include crude classification of exposure, low frequency and intensity of exposure, inadequate sample size, potential for confounding, retrospective study designs and lack of consistent diagnostic criteria for PD. Studies that assessed possible shared etiological components between PD and other diseases show that REM sleep behavior disorder and mental illness increase PD risk and that PD patients have lower cancer risk, but methodological concerns exist. Future epidemiologic studies of PD should be large, include detailed quantifications of exposure, and collect information on environmental exposures as well as genetic polymorphisms.