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Biomedical subjects

J T Hoff

Publications and source records attributed to J T Hoff.

At least 127 records · Page 7Linked to original sources
PubMed1984

Sodium 5-(3'-pyridinylmethyl)benzofuran-2-carboxylate (U-63557A) potentiates protective effect of intravenous eicosapentaenoic acid on impaired CBF in ischemic gerbils.

Eicosapentaenoic acid (EPA) has been reported to improve postischemic cerebral blood flow (CBF). The present study was designed to determine whether sodium 5-(3'-pyridinylmethyl)benzofuran-2-carboxylate (U-63557A), a selective thromboxane synthetase inhibitor, could potentiate the effects of EPA on CBF in ischemic gerbils. Ischemia was produced by bilateral carotid artery occlusion for 15 minutes followed by reperfusion for 2 hours. Immediately after ischemia, gerbils were given either an intravenous bolus of 0.167 mg of EPA followed by a continuous infusion of EPA at 1 mg/hr, or U-63557A (10 mg/kg intraperitoneally), or U-63557A and EPA, or a saline infusion. Regional CBF was measured by the hydrogen clearance method, and brain water by the specific gravity technique. Brain prostaglandins were measured by radioimmunoassay. Preischemic CBF's ranged from 27.4 to 29.5 ml/100 gm/min for the four animal groups. After ischemia and 2 hours of reperfusion, CBF in the saline-infused gerbils was significantly decreased to 19.2 ml/100 gm/min. Gerbils treated with either EPA or U-63557A alone had a CBF of 23.7 and 21.6 ml/100 gm/min, respectively. Postischemic CBF in animals treated with both U-63557A and EPA was 30.0 ml/100 gm/min, significantly higher than in saline-infused gerbils. Brain levels of 6-keto prostaglandin (PG)F1 alpha (the metabolite of PGI2) were significantly higher in gerbils treated with U-63557A and EPA compared to gerbils given EPA alone. This study indicates that U-63557A potentiates the effects of EPA on postischemic CBF. This is probably due to the ability of U-63557A to increase prostacyclin formation in the vessel wall.

Animals↗
PubMed1983

Ischemia reduces blood-to-brain glucose transport in the gerbil.

The effect of carotid occlusion on cerebral blood flow (CBF), brain plasma volume for sucrose (Vplsuc), and unidirectional transport of glucose from blood to brain was measured in four regions of gerbil brain. Unilateral common carotid artery occlusion caused a variable decrease in CBF to the ipsilateral cerebral cortex and basal ganglia, with no change in CBF to the contralateral structures; cerebellum, or brainstem. One hour of bilateral carotid artery occlusion reduced flow to near zero in the cerebral cortex and to 30% of control in the basal ganglia, while increasing CBF to the cerebellum and brainstem. There was a significant decrease in the Vplsuc of the cerebral cortex and basal ganglia after 1 h of ischemia, perhaps due to compression of the intravascular space by edema fluid. Blood-to-brain glucose transport, 1 min after release from 1 h of bilateral carotid occlusion, was decreased in the cerebral cortex and basal ganglia, but not in the cerebellum or brainstem. These data indicate that 1 h of complete or incomplete ischemia reduces the rate of unidirectional glucose transport from blood to brain.

Animals↗
PubMed1983

Adult Arnold-Chiari malformation and intrinsic brain stem neoplasm: a difficult differential diagnosis.

The occurrence of a brain stem neoplasm in three adults previously treated for an adult Arnold-Chiari malformation is reported. The diagnosis of adult Arnold-Chiari malformation had been confirmed by angiography and computed tomographic scanning. All patients were treated with a combination of ventricular shunts and posterior fossa decompression. The diagnosis of brain stem neoplasm was not made until late in the clinical course, and all patients died within 2 years of the onset of symptoms.

Adolescent↗
PubMed1983

The Wyburn-Mason syndrome. Concomitant chiasmal and fundus vascular malformations.

We report a 56-year-old female with a 50-year history of a progressive chiasmal syndrome who was found to have a suprasellar arteriovenous malformation involving the chiasm and both optic nerves associated with an unusual fundus picture consistent with the Wyburn-Mason syndrome. A review of the literature of this rare syndrome is also presented.

Blindness↗
PubMed1981

Experimental neurogenic pulmonary edema. Part 1: The role of systemic hypertension.

Neurogenic pulmonary edema (NPE) was produced consistently in normal cats by increasing intracranial pressure with an intraventricular infusion of mock cerebrospinal fluid. The usual elevation of systemic arterial pressure (SAP) that follows severe intracranial hypertension (the "Cushing response") was controlled by blood withdrawal at variable rates to achieve and maintain constant cerebral perfusion pressure (CPP) in three groups of cats of 50, 20, and 0 mm Hg, respectively, for 30 minutes. In this model, NPE occurs in the absence of increased SAP and in the presence of decreasing CPP. These results indicate that systemic arterial hypertension is not an essential stimulus for the development of NPE, and suggest that the lungs are directly affected by the intense sympathetic discharge evoked by severe intracranial hypertension.

Animals↗
PubMed1981

Experimental neurogenic pulmonary edema Part 2: The role of cardiopulmonary pressure change.

Pressure changes in the aorta, left atrium, and main pulmonary artery were measured before, during, and after inducing increased intracranial pressure in cats. By selectively controlling each of the three pressures, it was concluded that pulmonary arterial hypertension is the single most important precursor of experimental neurogenic pulmonary edema. An earlier observation that neurogenic pulmonary edema may develop in the absence of systemic arterial hypertension was confirmed.

Animals↗
PubMed1980

Intraspinal tumors in children.

Thirty cases of intraspinal neoplasms occurring during the first two decades of life are reviewed. Histologic examination showed 13 of these to be astrocytomas, 6 neuroblastomas, 5 sarcomas, 3 ependymomas, 2 neurofibromas and 1 a schwannoma. Orthopedic deformities developed or worsened in 60 percent of patients surviving longer than a year after diagnosis. In five patients some form of endocrine deficiency developed after irradiation. For treatment of radiosensitive extradural malignant lesions, biopsy followed by irradiation is advocated.

Adolescent↗
PubMed1979

Microsurgical approach to the anterior cervical spine and spinal cord.

When the cervical spine is affected by disease that is predominantly anterior, we prefer to take an anterior operative approach. Whether or not fusion is indicated depends largely upon the case. In general, we do not fuse the spine unless it is unstable. Widening of the spinal canal and the neural foramina can be done effectively by the anterior route, with or without anterior fusion. When the spine is unstable from disease affecting the vertebral bodies, we routinely fuse with bone graft or provide mechanical stability with a vertebral body prosthesis if life expectancy is short.

Bone Transplantation↗
PubMed1978

Brain death, apneic diffusion oxygenation, and organ transplantation.

This paper presents a simple method of maintaining good donor organ oxygenation during a prolonged test of apnea used to determine brain death prior to cadaver transplantation. Apneic diffusion oxygenation can maintain arterial pO2 above 200 torr for periods exceeding 15 minutes, thereby allowing a more definitive determination of brain death without concomitant tissue hypoxia and possible damage to donor organs.

Adult↗
PubMed1978

Experimental neurogenic pulmonary edema in cats.

Hemorrhagic pulmonary edema was produced consistently in 19 of 20 anesthetized, paralyzed, ventilated cats when intracranial pressure (ICP) was raised for 30 minutes by intraventricular infusion of mock CSF to 150 mm Hg in 14, or 200 mm Hg in six. However, under identical conditions, except that ICP was raised to only 100 mm Hg, three of seven animals did not develop hemorrhagic edema of the lungs and the remaining four had spotty hemorrhage. Thirteen control animals with normal ICP had normal lungs. Gravimetric lung water analysis by Pearce's method confirmed gross and microscopic appearance of hemorrhagic pulmonary edema. Extravascular lung water (p less than 0.05) and lung blood (p less than 0.05) were significantly greater than control values when ICP was raised to or exceeded 150 mm Hg. Despite hemorrhagic edema, pulmonary gas exchange (O2, CO2) remained unaffected. This animal model allows quantitative measurement of neurogenically-mediated hemorrhagic edema of the lungs before gas exchange is impaired. The model may facilitate clarification of the pathogenesis of neurogenic pulmonary edema and, consequently, refine evaluation of therapy.

Animals↗
PubMed1978

Decreased mortality from brain abscesses since advent of computerized tomography.

No deaths have occurred among 20 consecutive patients with intraparenchyma brain abscesses treated at the University of California, San Francisco, since computerized tomographic (CT) brain scanning became a routine diagnostic procedure (study period: July, 1974, to June, 1977). These patients have been compared to 18 consecutive cases treated without benefit of CT analysis (January, 1970, to June, 1974) in order to determine the factors responsible for the recently improved prognosis. The mortality rate was 44% for all cases and 36% for all operated patients treated before the availability of CT. Similar morbidity (about 33%) was seen in survivors from both series. No significant differences in the two groups were noted with respect to patient population and antibiotic or corticosteroid therapy. Among the factors that may have contributed to the improved results for patients diagnosed with CT are: less frequent occurrence of multiple abscesses, fewer patients with poor preoperative clinical status, and a greater incidence of total abscess removal. In addition, CT scanning provided more accurate diagnosis and localization of abscesses and aided in the rapid detection of postoperative complications that probably accounted for six out of eight deaths in the earlier series. Serial CT studies provide a means to optimize the timing for surgical intervention and plan appropriate medical therapy. It is noteworthy that two patients have been followed by serial CT scans to non-surgical cures.

Adult↗
PubMed1978

Head injury and early signs of tentorial herniation: a management dilemma.

In 100 patients intracranial exploration was done soon after severe head injury when signs of transtentorial herniation were present. A third of patients had extracerebral hematomas shown on initial burr hole examination. An additional 18 percent had parenchymal clots of clinical significance disclosed only by angiography after burr hole exploration or at autopsy. Half the patients in whom exploration was done did not have intracranial hematomas of sufficient size to warrant an operative approach. Detailed neurological examinations soon after injury and the availability of more rapid diagnostic tools may improve the accuracy of early diagnosis and allow more specific prognostication in patients with severe head injury.

Adolescent↗