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Biomedical subjects

U Tomiyasu

Publications and source records attributed to U Tomiyasu.

At least 19 recordsLinked to original sources
PubMed1990

Intracerebroventricular bethanechol for Alzheimer's disease. Variable dose-related responses.

Five male patients participated in a pilot open-label study of dose-related aspects of response to intracerebroventricular bethanechol in Alzheimer's disease. No patient had remission of symptoms, but three patients improved symptomatically and on tests of memory. Improvement was evident over a restricted range of doses for each subject, and symptoms were worse at doses below and above the optimal range. There was little overlap in the range of doses producing improvement among these three. Two patients had no consistent improvement in memory, and agitation, depression, paranoia, and seizures developed during treatment. Qualitative differences and variability in dosages producing responses complicate the identification of true drug response in the treatment of Alzheimer's disease.

Alzheimer Disease↗
PubMed1990

A quantitative study of dendrite complexity in selected areas of the human cerebral cortex.

This study seeks relationships between the degree of dendrite complexity of four areas of the human cerebral cortex and the type of function subserved by those areas. Quantitative studies of basilar dendrite patterns in the trunk and hand-finger receptive zones of areas 3 and 1, superior gyrus of the prefrontal cortex (area 9), and supramarginal gyrus (area 39) of the parietal lobe, in the left hemisphere of 10 subjects are reported. Measurements of dendrite complexity were based on the Sholl method of counting dendrite intersections with a series of superimposed concentric rings centered on the middle of the neuron soma. The data were analyzed graphically to show (1) characteristic dendrite profiles generated by cells in each of these areas, (2) comparisons between dendrite systems of two paired areas, i.e., trunk vs. hand-finger, and hand-finger vs. supramarginal, and (3) cumulative dendrite-ring intersection patterns for all areas studied. The data provided only partial support for our working hypothesis suggesting a relationship between complexity of the dendrite arbor and the nature of the computational tasks performed by the area. However, complexity of dendrite systems in the trunk area was found to be generally less than that of any other. In addition, there were suggestive associations between the complexity of dendrite systems of the hand-finger zone of the primary sensory receptive area and the nature of the work with which the individual had been associated during his/her working life. It proved more difficult to discern relationships between structure and function in the cortical associative areas. The study underlines the large degree of interindividual variation in dendrite structure and the need for much more extensive information about the life history of individuals who serve as subjects for this type of study.

Aged↗
PubMed1989

Lymphomatoid granulomatosis and malignant lymphoma of the central nervous system in the acquired immunodeficiency syndrome.

While primary and secondary malignant lymphomas have been well-documented in the CNS of patients with the acquired immunodeficiency syndrome (AIDS), only one case of lymphomatoid granulomatosis (LG) involving the CNS has been reported. We present three AIDS patients with multiple grossly evident foci of necrosis in the cerebral hemispheres which, on histologic evaluation, were seen to contain angiocentric mixed chronic inflammatory infiltrates with atypical mononuclear cells, luminal thrombosis, and infarction, which is typical of LG. LG was also identified in sections of the lung in one case. Lymphoma was found in other regions of the brain in two cases, suggesting the evolution of LG into cerebral lymphoma. In addition, widespread perivascular multinucleate syncytial giant cells, associated with human immunodeficiency virus (HIV) infection of the CNS, were identified in all patients. The features of LG, its relationship to lymphoma, and the possible etiologic role of an immunodeficiency state or the HIV virus in the pathogenesis of LG are discussed.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Cytomegalovirus in the nervous system of patients with the acquired immune deficiency syndrome.

Clinicopathological features of infection of the nervous system by cytomegalovirus (CMV) in 31 patients with the acquired immune deficiency syndrome (AIDS) are reviewed. Neuropathology was variable, ranging from rare isolated CMV inclusions in brain without associated inflammation or necrosis, to severe necrotizing ependymitis and meningoencephalitis. In 1 patient, CMV had produced a necrotizing meningoradiculitis which presented clinically as ascending paralysis. In the brains and spinal cords of 6 patients, evidence of human immunodeficiency virus (HIV) infection of neural parenchyma was seen in close proximity to CMV infection. Both viruses individually or together were associated with low grade (microglial nodule) encephalitis. In retrospect, the diagnosis of CMV had been a difficult one to make clinically in neurologically impaired patients with AIDS. The results suggest that CMV may also localize in the nervous system without significant clinical sequelae. Imaging studies and analysis of cerebrospinal fluid revealed abnormalities in many patients, but none of them (short of culture of CMV itself in two cases) appeared to be specific to this neurological complication of the immunodeficiency.

Acquired Immunodeficiency Syndrome↗
PubMed1987

Denervation microangiopathy in senile dementia, Alzheimer type.

Structural analysis of the capillary plexus in the brains of 5 patients with clinical and neuropathological diagnosis of Senile Dementia, Alzheimer Type, revealed a group of striking physical alterations compared with tissue specimens from 5 age-matched controls. Capillary walls were thickened with irregular lumpy, nodulated contours which appeared due, in part, to infiltration of the vascular wall with rounded cell-like bodies. In some cases, these resembled the perikarya of pericytes or monocytes, or their protoplasmic extensions, which were often filled with lipids. In each case, there was no trace of the perivascular neural plexus which regularly invests the microvasculature of the brain parenchyma. The loss of this neural plexus, believed to originate largely from locus ceruleus and the basal forebrain, may be related to the changes in capillary wall structure, and these, in turn, may lead to profound alterations in blood-brain barrier function. We suggest that this subcortically induced denervation microangiopathy may serve as a pathogenic factor in the development of SDAT.

Aged↗
PubMed1986

The neuropathology of AIDS. UCLA experience and review.

The central nervous system (CNS) has been examined at autopsy in 89 patients who died of the acquired immune deficiency syndrome (AIDS), including 14 patients who died primarily of neurologic complications of the disease. A total of 66 brains (74%) showed significant pathologic abnormalities, with opportunistic infections including cytomegalovirus (14) and cryptococcal (11) infections, progressive multifocal leukoencephalopathy (6), toxoplasmosis (6), and histoplasma microabscesses (1). Incidental Mycobacterium avium-intracellulare infection was found in 4 cases. Simultaneous CNS infection by more than one microorganism was encountered in 5 patients. Subacute (microglial nodule) encephalitis-related to cytomegalovirus infection or possibly brain infection by the causative agent of AIDS was present in 56 cases. Primary CNS lymphoma was noted in 3 patients. Secondary CNS deposits of lymphoma were found in 1 patient, and another patient had lymphomatoid granulomatosis. Vascular complications were not infrequently seen, and included infarcts secondary to vessel occlusion and disseminated intravascular coagulation in 4 patients and intracranial hemorrhage of variable severity in 13. White matter changes included vacuolar myelopathy (3 cases), central pontine myelinolysis (1 case), and foci of calcified, necrotizing leukoencephalopathy in pontocerebellar fibers of the basis pontis (2 cases). These findings highlight the variety of CNS complications in AIDS, some of which are not associated with clinical manifestations. Nevertheless, characterization of all lesions may be important in understanding the neurologic sequelae of AIDS.

Adult↗
PubMed1985

Dendritic organization of the anterior speech area.

Golgi studies revealed significant differences in dendritic patterns between neurons of the left and right opercular regions of the frontal lobe (Broca's speech area on the dominant side) and between cells of the left and right precentral areas (the orofacial motor zones) just behind. Although total dendritic length of the basilar dendritic array seemed characteristic of an area independent of side, a larger proportion of the length on the left (dominant) side was made up of higher order (4, 5, 6) dendrite branches, and lower order (1, 2, 3) segments predominated on the right. The pattern was partially reversed in non-right-handed patients. These findings can be interpreted as indicating an early preponderance of dendrite growth in the non-speech-gifted hemisphere followed by enhanced dendrite growth in the dominant hemisphere coincident with the beginning of conceptualization and speech function.

Aged↗
PubMed1985

Immunocytologic localization of herpes simplex type 1 viral antigens in herpetic retinitis and encephalitis in an adult.

An immunoperoxidase technique was utilized to identify herpes simplex type I viral antigens in the retina, optic nerve and brain of an adult with herpetic retinitis and encephalitis. Viral antigens were demonstrated in all layers of retina, retinal pigment epithelium and to a lesser extent, in choroid. Oligodendroglia in the right optic nerve and neuronal and glial cells in the grey and white matter of the left frontal, inferior parietal and temporal lobes of the brain also expressed herpes simplex antigens. The sensitive immunoperoxidase method allowed detection of viral antigens in many cells without intranuclear inclusions or surrounding inflammation, and thereby added valuable information regarding the anatomic and cellular localization of herpetic infection. The clinicopathologic features that characterize herpes simplex retinitis in the adult are compared to cytomegalovirus retinopathy.

Acquired Immunodeficiency Syndrome↗
PubMed1978

Spinal intramedullary glioblastoma with intracranial seeding. Report of a case.

Approximately one year after partial removal of an intramedullary glioblastoma at T12, a patient was admitted to Wadsworth Veterans Administration Hospital with signs and symptoms of an intracranial tumor. We describe the unusual occurrence of intracranial seeding from spinal glioblastoma and review this rare condition and the possible mechanism involved.

Brain Neoplasms↗
PubMed1977

Primary position upbeat nystagmus. A clinicopathologic study.

Eye movements were studied with electro-oculography in a patient with primary position, large amplitude, upbeat nystagmus. The upbeat nystagmus increased in amplitude on upward gaze, decreased on downward gaze, and was not altered by loss of fixation. The patient could not produce smooth pursuit movements upward or to the left, but had normal saccadic and vestibular induced eye movements in all directions. At necropsy, a low grade glioma was found involving primarily the medulla and caudal pons. The inferior olives and prepositus hypoglossal nuclei were diffusely infiltrated with tumor. These results suggest (1) primary position upbeat nystagmus is due to a defect in the upward smooth pursuit system, (2) the lower brain stem at the level of the inferior olives and nucleus prepositus hypoglossi is important in the mediation of vertical pursuit, and (3) primary position upbeat nystagmus can result from damage to several nuclei and interconnecting pathways in the caudal brain stem and midline cerebellum involved in control of vertical smooth pursuit.

Ataxia↗