Biomedical subjects

William Byne

Publications and source records attributed to William Byne.

5 recordsLinked to original sources

PubMed2003

Loss and altered spatial distribution of oligodendrocytes in the superior frontal gyrus in schizophrenia.

BACKGROUND: Brain imaging, molecular genetic, and ultrastructural evidence indicate the existence of pathologic alterations in the cortical and subcortical white matter of schizophrenic patients. METHODS: We performed a stereologic analysis of numbers, densities, and spatial distribution of oligodendrocytes in layer III and in the gyral white matter of Brodmann's area 9 in the superior frontal gyrus to assess whether these cells are affected in schizophrenia. Counts were obtained on Nissl-stained materials and on sections immunolabeled for the oligodendrocyte marker 2',3'-cyclic nucleotide-3'-phosphodiesterase (CNPase) in seven schizophrenic and seven age-matched control cases. RESULTS: A 28% decrease in total numbers (or densities) of cortical layer III oligodendrocytes and a 27% decrease in the white matter were detected in schizophrenic compared with control cases based on CNPase immunostaining. Nissl and CNPase immunohistochemistry yielded comparable results. The spatial distribution of oligodendrocytes in area 9 white matter exhibited a less clustered arrangement in schizophrenic cases. CONCLUSIONS: These results suggest a severe pathology of oligodendrocytes in schizophrenia and provide a quantitative cellular correlate of the white matter changes observed by brain imaging in vivo, showing reduced fractional anisotropy in schizophrenia. The data support recent evidence that several genes encoding myelin-related proteins consistently exhibit reduced expression in schizophrenia.

2',3'-Cyclic-Nucleotide Phosphodiesterases↗

PubMed2002

Evidence for a decrease in basilar dendrites of pyramidal cells in schizophrenic medial prefrontal cortex.

A variety of lines of converging evidence implicates the prefrontal cortex (PFC) in schizophrenia. Previous neuroanatomical studies have shown schizophrenia-associated changes in neuron density, soma size and spine number. We recently demonstrated a schizophrenia-associated decrease in microtubule-associated protein 2 (MAP2) immunostaining in laminae III and V of medial prefrontal area 32 and interpreted that finding as suggestive of a loss of dendritic material. We now present data from medial prefrontal area 32 of 11 schizophrenics and 11 comparison subjects. In Golgi-stained material, we describe a significant decrease in the number of both primary (29%) and secondary (46%) basilar dendrites on pyramidal neurons in layer V. Similarly, in layer III there was also a decrease in both primary (17%) and secondary (15%) basilar dendrites. These findings suggest a decrease in synaptic surface area which could lead to aberrant information processing.

Adult↗

PubMed2002

Alterations in MAP2 immunocytochemistry in areas 9 and 32 of schizophrenic prefrontal cortex.

A variety of lines of converging evidence implicate the prefrontal cortex (PFC) in schizophrenia. Studies employing Nissl stains have suggested that PFC dendrites may be atrophic in schizophrenia; however, Nissl stains do not reveal dendrites. We employed MAP2 immunocytochemistry, which stains dendrites to examine cortical layers III and V in two areas of the PFC (areas 9 and 32). Occipital cortex (area 17) was examined as a control region. Tissues from seven schizophrenics and seven non-psychiatric controls were examined. Immunostaining was quantitated by area fraction analysis. MAP2 area fraction was decreased in both layers in both regions of PFC, but not in occipital cortex. Area 9 exhibited a 42% reduction in layer V and a 36% reduction in layer III. Area 32 exhibited a 31% reduction in layer V and a 36% reduction in layer III. Neither region exhibited a significant change in the density of pyramidal cells. These data are consistent with the hypothesis of a schizophrenia-associated decrease in dendritic material in the PFC.

Adult↗

PubMed2002

A lack of dimorphism of sex or sexual orientation in the human anterior commissure.

Four studies have examined the cross-sectional area of the anterior commissure (AC) for variation with sex, with conflicting results. One also reported the AC to be larger in homosexual as opposed to heterosexual men. We examined the cross-sectional area of the AC in postmortem material from 120 individuals, and found no variation in the size of the AC with age, HIV status, sex, or sexual orientation.

Adult↗

PubMed2002

Postmortem assessment of thalamic nuclear volumes in subjects with schizophrenia.

OBJECTIVE: The authors assessed schizophrenia-associated changes in volume and neuronal number in the mediodorsal nucleus and the pulvinar regions of the thalamus. METHOD: Right-hemisphere thalami obtained at autopsy from 14 schizophrenic and eight comparison subjects were examined. Computer-assisted morphometric techniques were used to determine volumes for the mediodorsal nucleus, pulvinar, and the anterior and centromedian nuclei as well as the parvocellular, magnocellular, and caudodorsal subdivisions of the mediodorsal nucleus. Neurons in the mediodorsal nucleus and pulvinar were counted and measured by using a stereology-based sampling strategy. RESULTS: Four schizophrenic and three comparison subjects had Alzheimer's type pathology, leaving 10 schizophrenic and five comparison subjects without other documented neuropathological changes. In analyses that included either the full cohort or only the subjects without Alzheimer's type pathology, volumes of the mediodorsal nucleus and pulvinar, but not the anterior or centromedian nuclei, were significantly smaller in the schizophrenic subjects. For the schizophrenic subjects, neuronal number in the mediodorsal nucleus, parvocellular subdivision, and pulvinar was significantly lower, and neuronal size in the mediodorsal nucleus, caudodorsal subdivision, and pulvinar was significantly smaller. CONCLUSIONS: Schizophrenia is associated with volume and neuronal changes in the mediodorsal nucleus and pulvinar, the major association nuclei of the thalamus, whereas total thalamic volume and the volumes of anterior and centromedian nuclei were not significantly altered.

Aged↗