Cerebral blood flow in schizophrenia.

The regional cerebral blood flow of 27 young (mean age 24 years) schizophrenic patients was measured using the intravenous 133Xe method. The results were compared with those obtained from a group of age- and sex-matched control subjects. The main findings of the study were as follows: (a) the gray matter mean values of cerebral blood flow for both hemispheres were slightly but significantly lower in the schizophrenic group, and the statistical variance was significantly greater in the patients than in the control group; (b) the mean value for each hemisphere was found to be significantly lower for the right hemisphere; (c) the physiological hyperfrontal patterns of cerebral blood flow were identical in patients and controls; (d) visual hallucinations were associated with a reduction of regional cerebral blood flow in the temporo-occipital regions; and (e) antipsychotic medication did not appear to influence gray matter cerebral blood flow.

Cerebral blood flow in systemic lupus erythematosus with and without central nervous system involvement.

Regional cerebral blood flow (rCBF) was studied by the intravenous 133Xe method in 38 patients with systemic lupus erythematosus (SLE); 21 patients had neuropsychiatric manifestations (N+) and 17 did not (N-). Twelve of the N+ patients had had neuropsychiatric episodes less than one year before measurement of CBF ("recent" N+), while seven patients in this group had had episodes over a year before measurement ("old" N+). The results were compared with those obtained from a group of 27 age-matched normal healthy subjects. It was found that, in most of the N+ and N- patients, rCBF was evenly distributed bilaterally, but there was a "patchwork" of high/normal and low flow areas. This disturbance of rCBF distribution was significantly greater in "recent" N+ patients than in "old" N- patients, but was not a function of the potential evolution of systemic lupus erythematosus. It was also found that there was a reduction in the physiological high frontal rCBF in the "old" N+ patients. No correlation could be found between rCBF, the topography of the neuropsychological lesions, other neurological investigations or the glucocorticoid dosage and treatment schedules.

Cerebral blood flow in normal pressure hydrocephalus.

A xenon-133 method was used to measure cerebral blood flow (CBF) before and after cerebrospinal fluid (CSF) removal in patients with normal pressure hydrocephalus (NPH). Preliminary results suggested that shunting should be performed on patients whose CBF increased after CSF removal. There was a significant increase in CBF in patients with NPH, which was confirmed by the favorable outcome of 88% of patients shunted. The majority of patients with senile and presenile dementia showed a decrease or no change in CBF after CSF removal. It is suggested that although changes in CBF and clinical symptoms of NPH may have the same cause, i.e., changes in the cerebral intraparenchymal pressure, there is no simple direct relation between these two events. The mechanism underlying the loss of autoregulation observed in NPH is also discussed.

[Study of the cerebral blood flow by intravenous injection of xenon-133 in thalamic and juxtathalamic lesions]. / Etude du débit sanguin cérébral par injection intra-veineuse de xénon 133 lors de lésions thalamiques et juxta-thalamiques.

Sixteen patients with subcortical vascular lesions of one hemisphere, (7 left, including 4 aphasics and 9 right, 4 of which had a left neglect syndrome) and 4 controls without noticeable cerebral pathology underwent cerebral blood flow (CBF) measurements with intra-venous Xe 133, both at rest and during activation. The latter consisted of listening to a text together with eye opening and was considered non specific. At rest, a non significant CBF lowering on the side of the lesion was found in most patients, mainly in right brain damaged ones. Hypoperfusion areas (HA) were noted, predominantly in parieto-temporal cortex in right lesions, and in lower and middle frontal areas as well in left lesions. HA persisted during activation on both sides, except on the right side in left damaged patients. Activation resulted in a bilateral and roughly symmetrical mean CBF increase, which was not significant in left lesions nor in controls, but was significant (p less than .05) in right brain damaged patients without neglect syndrome. Conversely, patients with right lesions resulting in left neglect exhibited conspicuous mean CBF asymmetry during activation with depression on the right side. Right-left difference in mean CBF was significantly higher in this group than in right sided lesions without neglect (p less than .05). These facts are consistent with an activation imbalance between hemispheres as the mechanism of unilateral neglect syndromes, and support the view that right subcortical pathways and especially the thalamus, play a part in the activation of both cerebral hemispheres.

[Cardiac effects of the flow in the arteriovenous fistula. Study in 66 chronic hemodialysis patients]. / Retentissement cardiaque du débit de la fistule artério-veineuse. Etude chez 66 hémodialysés chroniques.

The effect on the heart of blood flow in the arterio-venous fistula created for haemodialysis was investigated in 66 patients with chronic renal impairment. Blood flow was measured by pulsed Döppler flowmetry. A significant (p less than 0.001) correlation was established between the signs of cardiac insufficiency and the fistula blood flow x fistula duration product. The arterio-venous fistula therefore constitutes a cardiac risk which should be quantified in chronically uraemic patients undergoing repeated haemodialysis.