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Biomedical subjects

R L Grubb

Publications and source records attributed to R L Grubb.

At least 73 records · Page 4Linked to original sources
PubMed1984

Extracranial-intracranial bypass surgery: hemodynamic and metabolic effects.

After superficial temporal artery-middle cerebral artery bypass, cerebral blood flow (CBF) in the operated hemisphere increased in 6 of 17 patients. Preoperatively, the symptomatic hemisphere showed lower CBF in all six, lower oxygen metabolism in five, higher blood volume in four, and higher oxygen extraction in two. With the postoperative increase in hemispheric CBF, there was a decrease in oxygen extraction, but no change in blood volume or oxygen metabolism. In these patients, chronic regional hypoperfusion followed major vascular occlusion. Compensatory responses included dilation of intraparenchymal vessels and increased transport of oxygen from blood to tissue. These changes were partially reversed by cerebral revascularization.

Adult↗
PubMed1983

Complete fracture-dislocation of cervical spine without permanent neurological sequelae. Case report.

A case of complete fracture-dislocation of the lower cervical spine in which there were no permanent neurological sequelae is presented. The absence of permanent neurological deficits with this type of injury is rare. The primary mechanism of injury in this patient was believed to be hyperextension with rupture of the ligamentous structures, allowing complete dislocation of the C-6 body while the posterior elements remained in good alignment due to multiple fractures which "decompressed" the spinal cord.

Fractures, Bone↗
PubMed1983

Maternal hydrocephalus and pregnancy.

Women with cerebrospinal fluid (CSF) shunts for correction of hydrocephalus are rapidly joining the reproductive age population. These patients can have uncomplicated pregnancies and spontaneous vaginal deliveries. Careful attention to signs of CSF shunt malfunction, historical and ultrasonic screening for familial hydrocephalus, and antibiotic prophylaxis for delivery are recommended. Management of the first and second stages of labor is discussed. There is no apparent advantage to any particular technique for intrapartum analgesia.

Adult↗
PubMed1982

Effects of hemorrhagic and pharmacologic hypotension on cerebral oxygen utilization and blood flow.

Cerebral oxygen utilization and blood flow were measured by the washout of oxygen-15 isotopes injected into the internal carotid artery in baboons during hypotension produced by acute hemorrhage, trimethaphan, and sodium nitroprusside. Acute hemorrhage, trimethaphan, and sodium nitroprusside lowered the mean arterial blood pressure to 52 per cent, 55 per cent, and 47 per cent, respectively, of control values. There were corresponding decreases in cerebral blood flow to 76 per cent (P less than 0.01), 81 per cent (P less than 0.05), and 79 per cent (P less than 0.01) of control values. When the mean arterial blood pressure was decreased 11 per cent with hemorrhage, auto-regulation of the cerebral vasculature was preserved and cerebral oxygen utilization increased 10 per cent (P less than 0.01). When cerebral autoregulation was lost with acute hemorrhage, cerebral oxygen utilization declined 17 per cent (P less than 0.05). When cerebral autoregulation was lost with pharmacologic hypotension, cerebral oxygen utilization was preserved with trimethaphan and increased 17 per cent (P less than 0.05) with sodium nitroprusside. The increase in cerebral oxygen utilization seen with sodium nitroprusside and hemorrhagic (autoregulation preserved) hypotension may be due to stimulation of the sympathetic nervous system with release of circulating catecholamines. However, the mechanism by which circulating catecholamines mediate an increase in cerebral oxygen metabolism during hypotension is not clear.

Animals↗
PubMed1981

Cerebral hemodynamics and metabolism in postoperative cerebral vasospasm and treatment with hypertensive therapy.

A 24-year-old woman developed subarachnoid hemorrhage from an aneurysm at the bifurcation of the right internal carotid artery. Following successful clipping of the aneurysm she developed a left hemiplegia associated with focal cerebral vasospasm, which markedly improved when systemic blood pressure was raised with intravenous dopamine infusion. Regional cerebral blood flow and oxygen utilization were significantly depressed in both cerebral hemispheres, while blood volume was significantly elevated only on the side with vasospasm. Oxygen extraction was significantly elevated in both hemispheres, indicating a generalized impairment in oxygen delivery to the brain.

Adult↗
PubMed1979

Regional cerebral blood flow and oxygen utilization in superficial temporal-middle cerebral artery anastomosis patients: an exploratory definition of clinical problems.

Regional cerebral blood flow (rCBF) and regional cerebral oxygen utilization (rCMRO2) were measured before and after surgery in nine patients undergoing a superficial temporal artery-middle cerebral artery (STA-MCA) anastomosis to bypass cerebrovascular lesions not amenable to extracranial operative procedures. The objective of these studies was to determine whether measurements of this type could provide objective criteria for surgery as well as assess the effect of surgery. The preliminary data, although limited, suggest that measurements of regional cerebral hemodynamics and metabolism in these patients before and after surgery provide valuable data upon which to develop criteria and assess results. For example, 1) a significant depression of rCBF and rCMRO2 in patients in whom a major cerebral infarction has not occurred, or 2) relative preservation of rCMRO2 despite depressed rCBF seem to be favorable indications for establishing a functioning STA-MCA anastomosis. In such patients, STA-MCA anastomosis can be followed by a return of rCBJ and rCMRO2 to virtually normal levels. Relatively normal rCBF and rCMRO2 in the presence of an occluded internal carotid artery in asymptomatic patients indicates satisfactory collateral circulation and is probably a contraindication to surgery.

Adult↗
PubMed1978

Central neuroendocrine regulation of brain water permeability.

The brain vasculature, especially capillaries, may function in a very dynamic fashion under neuroendocrine control to regulate the internal environment of the brain. This is exemplified by new observations on the regulation of brain water permeability using the tracer H215O in vivo in adult rhesus monkeys. These studies reveal that brain water permeability, and hence brain water content and volume, are, at least in part, under the influence of the central noradrenergic system and centrally released vasopressin.

Animals↗
PubMed1978

Cerebral hemodynamics and metabolism in pseudotumor cerebri.

A comprehensive analysis of cerebral hemodynamics and metabolism was carried out in 14 patients with pseudotumor cerebri. Tracer techniques were employed to measure cerebral blood flow (CBF) and vascular reactivity to acute changes in arterial carbon dioxide tension and blood pressure, cerebral blood volume (CBV), and the cerebral metabolic rate for oxygen and glucose. There was a small reduction (p less than 0.01) in CBF (44 +/- 7 ml/100 gm/min; normal, 54 +/- 9) with normal vascular reactivity; an increase (p less than 0.005) in CBV (4.8 +/- 0.8 ml/100 gm; normal, 3.6 +/- 0.5), and normal cerebral metabolism. We conclude that an abnormality of the cerebral microvasculature is responsible for an elevation in CBV, but the intracranial hypertension can be explained only by tissue swelling due to an increase in water content. The relationship between the vascular abnormality and the tissue swelling remains to be defined.

Adolescent↗
PubMed1978

Measurement of regional cerebral blood volume by emission tomography.

The technique of positron emission tomography was used to measure cerebral blood volume (CBV) in 10 normal right-handed human volunteers following inhalation of trace quantities of cyclotron-produced, 11C-labeled carbon monoxide. In scans obtained 4 cm above the orbitomeatal line, CBV was 4.3 ml per 100 gm of tissue, whereas in scans obtained 8 cm above the orbitomeatal line, CBV was significantly less (3.3 ml per 100 gm; p less than 0.001). This difference reflects the greater proportion of gray matter in the lower scan. Furthermore, the CBV was significantly larger (p less than 0.001) in the left cerebral hemisphere in the tomographic scans obtained 4 cm above the orbitomeatal line. These scans include the region of the superior surface of the temporal lobe (planum temporale), which is thought to be larger in individuals with left cerebral dominance for speech. This observation is the first in vivo demonstration of a structural correlate of a known functional difference in the cerebral hemispheres of man.

Blood Volume Determination↗
PubMed1978

Adult idiopathic communicating hydrocephalus with and without shunting.

The outcome in 37 adult patients with idiopathic communicating hydrocephalus treated by ventriculoatrial shunting is presented. Only 33% showed definite improvement, and no diagnostic procedures accurately predicted the outcome of surgery. These were compared with a "control" group of 12 patients who were not shunted; 50% of these were stable for up to 36 months. These findings, and the high frequency of serious complications (35%), suggest caution in recommending a shunt procedure.

Aged↗