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Biomedical subjects

B R Brooks

Publications and source records attributed to B R Brooks.

142 records · Page 8Linked to original sources
PubMed1977

Cerebrospinal fluid GABA reductions in seizure patients evoked by cerebellar surface stimulation.

Lumbar cerebrospinal fluid (CSF) gamma-aminobutyric acid (GABA) levels determined by fluorometric assay in four seizure patients were found to be significantly lower during bilateral, continuous cerebellar stimulation than those determined after a 7-day period without stimulation. The CSF GABA concentrations during chronic unilateral, alternating cerebellar stimulation were reduced in three seizure patients but unchanged in a fourth patient. The percentage decrease in CSF GABA appeared to be independent of cerebellar stimulation frequency. These findings suggest that GABA-mediated neuronal transmission is depressed during cerebellar surface stimulation and this evoked reduction in GABA activity may compromise the efficacy of cerebellar stimulation in the treatment of epilepsy. Lumbar CSF cyclic guanosine monophosphate levels determined by radioimmunoassay were not significantly altered by either mode or frequency of cerebellar stimulation.

Aminobutyrates↗
PubMed1976

Adult-onset acid maltase deficiency. Morphologic and biochemical abnormalities reproduced in in cultured muscle.

We established muscle-tissue cultures from biopsy of a patient with adult-onset acid maltase deficiency. Morphologically and biochemically, the newly grown fibers of the cultured muscle showed the same abnormalities as those of the biopsied muscle. Light microscopy showed multiple vacuoles filled with acid-phosphatase-positive material; on ultrastructural examination there was abnormal accumulation of glycogen in membrane-bound sacs (secondary lysosomes), some of which also contained dark membranous of homogeneous material. Acid maltase (pH 4.0), a lysosomal enzyme, was undetectable in either cultured or biopsied muscle by maltose hydrolysis, whereas acid phosphatase, also a lysosomal enzyme, was increased in both sources of muscle cells. Cultured muscle fibers demonstrate the same morphologic and biochemical abnormalities characteristic of biopsied muscle, supporting the concept of a biochemically distinct primary myopathy in man.

Acid Phosphatase↗
PubMed1975

Cerebrospinal fluid acid-base and lactate changes after seizures in unanesthetized man. I. Idiopathic seizures.

The natural course of acid-base changes in arterial blood and lumbar cerebrospinal fluid of patients admitted after major motor seizures was correlated with simultaneously determined lactate levels. In 10 patients with idopathic seizures studied less than 3 hours after the seizure, arterial lactate and cerebrospinal fluid lactate were elevated in association with a mild arterial metabolic acidosis. The elevated cerebrospinal fluid lactate persisted despite a return to normal of the arterial lactate in seven patients studied between 3 and 6 hours after the seizure. All values were normal in five patients studied more than 4 days after a major seizure.

Acid-Base Equilibrium↗
PubMed1975

Cerebrospinal fluid acid-base and lactate changes after seizures in unanesthetized man II. Alcohol withdrawal seizures.

Acid-base changes in arterial blood and lumbar cerebrospinal fluid were correlated with simultaneously determined lactate levels in patients admitted after alcohol withdrawal seizures. Arterial and cerebrospinal fluid lactate was elevated in association with a marked respiratory alkalosis in 13 patients studied 5 to 12 hours after the seizure. Similar elevations of arterial and cerebrospinal fluid lactate were found in five patients during delirium tremens without antecedent withdrawal seizure. The cerebrospinal fluid lactate determined on admission appeared to correlate best with the length and severity of the alcohol withdrawal syndrome that developed in patients after a withdrawal seizure.

Adult↗
PubMed1975

Computerized axial tomography: clinicopathologic correlation.

Between August 1973 and April 1974 more than 750 patients had computerized axial tomography (CT) scans at the Massachusetts General Hospital. Ten brains from previously CT-scanned patients in this group were sectioned in the plane of the scan. Nearly exact correlation was found between the anatomic location and extent of intracranial lesions demonstrated by CT scan and the findings on gross and microscopic pathologic examination in cases of primary intracranial tumors, obstructive hydrocephalus, intracerebral hemorrhage, ischemic and hemorrhagic infarctions, pineal tumor, and thermal-burn encephalopathy. Determination of absorption values (mu) of 47 pathologically verified processes showed that high-absorption intracerebral hemorrhage and calcium-containing tumors are readily separable from other processes on the basis of mu values alone. However, the abnormal mu values of primary brain tumor, edema, and infarction are difficult to distinguish from those of normal spinal fluid and white matter.

Autopsy↗
PubMed1967

Aggression.

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Aggression↗
PubMedDate not supplied

Spongiform polioencephalomyelopathy caused by a murine retrovirus. II. Ultrastructural localization of virus replication and spongiform changes in the central nervous system.

The development of murine retrovirus induced spongiform polioencephalomyelopathy was studied sequentially by electron microscopy. During the initial 30 days, viral infection of the central nervous system, as evidenced by viral budding from membranes, was limited to the endothelial cells and pericytes. Viral particles were observed in the lumen of blood vessels, extracellular spaces and astrocytic endfeet surrounding blood vessels, but no morphological evidence of productive infection was found in astrocytes or neurons during early development of vacuolation. The earliest lesions in the neuropil consisted of swelling of astroglia followed by vacuolation, initially in axons and dendrites and later in neuronal and astrocytic soma, where vacuoles appeared to arise from dilated cisternae of the Golgi apparatus. Vacuoles contained only amorphous debris and fragments of membranes. Virions budding aberrantly into vacuoles were seen only in mice surviving beyond 35 days. Numerous reactive astrocytes were observed, but inflammatory cells were absent. The ultrastructural changes were remarkably similar to those described in scrapie, Kuru, and Creutzfeldt-Jakob disease.

Animals↗
PubMedDate not supplied

Elevations in cerebrospinal fluid norepinephrine during unilateral and bilateral cerebellar stimulation in man.

Lumbar cerebrospinal fluid (CSF) norepinephrine concentrations determined by radioenzymatic assay in four epileptic patients were significantly higher during either chronic unilateral or bilateral cerebellar stimulation than those determined after a 7-day period without stimulation. The mean CSF norepinephrine levels noted during these two modes of cerebellar stimulation were not significantly different. The percentage of increase in CSF norepinephrine in one patient receiving 200/sec stimulation was 3 times higher than those noted in the three patients undergoing 10/sec stimulation. These evoked alterations in norepinephrine metabolism may relate to the reported modulation of spasticity and cerebral neuronal excitability during chronic cerebellar stimulation. Lumbar CSF cyclic adenosine monophosphate levels determined by radioimmunoassay were not significantly altered by either mode or frequency of cerebellar stimulation.

Cerebellum↗