Biomedical subjects
J R Thompson
Publications and source records attributed to J R Thompson.
Therapeutic embolization for vascular trauma of the head and neck.
Therapeutic embolization is an effective and relatively safe method for managing many cases of head and neck trauma. In the last 5 years, 78 traumatic vascular lesions--10 arterial transections and 68 arteriovenous fistula--were treated by intravascular embolization at four medical centers. Selection of embolic materials is discussed and different types of lesions are illustrated. Treatment was successful in every instance. Complications were limited to one case of cerebral infarction and two cases of temporary oculomotor weakness. The indications for embolization have widened beyond life-threatening hemorrhage alone, and continued improvement in techniques and embolic agents should see an increased use of this form of treatment.
Dislocation of the temporomandibular joint disk demonstrated by CT.
Explore the source record for details and available documents.
CT scanning phantom for normalization of infant brain attenuation.
The x-ray attenuation values of brain studied with computed tomography (CT) are strikingly affected by the ages of the subjects. Premature neonates, for example, may have brain attenuation values 20-30 H below adult values. These lower attenuation values for developing compared with adult brain can be ascribed partly to machine-related effects (beam-hardening, adult algorithms, scanning geometry, etc.). A scanning phantom made from aluminum was developed that can be used to develop a nomogram for any particular scanner from which normalized brain attenuation may be derived for any small head size. Using this nomogram, predicted neonatal attenuations are still 10-15 H higher than those actually observed in scanning neonates. The model predicts that, at the most, 3-4 H of this discrepancy can be accounted for by less beam-hardening from the lower bone attenuation of the thinner developing skull. Presumably, the rest is from a lower brain density in neonates (higher water content). By normalizing to cerebrospinal fluid (water) with special care to avoid partial-volume artifacts, one can predict attenuation values for developing brain more accurately.
Radiodense dural sinuses: new CT sign in patients at risk for hypoxemic insult.
The observation of apparent dural sinus opacification in a polycythemic patient with cerebral infarction prompted a review of 300 computed tomographic scans for the significance of dense dural sinuses. Fifteen patients including 11 neonates, were identified; each of them had dense dural sinuses and elevated hematocrit or red blood cell indices or both. With only one exception, computed tomography also showed various low attenuation parenchymal abnormalities. A typical cerebral infarction pattern was seen in six and parenchymal hemorrhage in one. Nonthrombotic dural sinus opacification is a sign of increased blood viscosity in patients with congenital heart disease, hemoconcentration states, polycythemia of the newborn, and polycythemia rubra vera. These patients are at high risk for hypoxemic cerebral insult, which can be detected by cranial computed tomography.
Effect of sex, testosterone propionate and trienbolone acetate on the rate of growth and myofibrillar protein degradation in growing young rats.
The urinary output of N tau-methylhistidine (3-methylhistidine: 3-Mehis) was determined to evaluate the effect of testosterone propionate (TP, 1 mg/100g body weight per day) and trienbolone acetate (3-oxo-17 beta-hydroxy-4,9,11-estratriene acetate, TBA 1 mg/100g body weight per day) on the rate of myofibrillar protein breakdown in young growing intact and adrenalectomized (AdX) male and female rats. Injections were given subcutaneously for 14 days. Body weight changes were recorded daily throughout the experiment. Compared with the intact control rats, male-AdX rats had a significant (p less than 0.05) reduction in both growth and 3-Mehis output (and, therefore, a reduction in the rate of myofibrillar protein degradation). Administration of the anabolic steroids to these rats had no significant effect on growth but increased the rate of 3-Mehis output to the normal range in the case of TP, and above the normal range (p less than 0.05) in the case of TBA. However, compared with the intact female rats, female-AdX rats showed a significant (p less than 0.05) increase in 3-Mehis output. Administration of either TP or TBA to these animals significantly (p less than 0.05) increased growth and reduced 3-Mehis output. The response of myofibrillar protein degradation in AdX rats to TP or TBA administration is strongly dependent on the sex of the animals. The anabolic action of TP and TBA, especially in female rats, may be mediated through an antagonistic effect to the catabolic effects of oestrogens and glucocorticoids.
Myofibrillar protein breakdown in intact and adrenalectomized female rats treated with testosterone propionate.
Explore the source record for details and available documents.
Effect of ovariectomy on the rate of muscle protein breakdown in the rat.
Explore the source record for details and available documents.
Allan Gibson Brodie, Sr., D.D.S. 1897-1976.
Explore the source record for details and available documents.
Hyperventilation-induced cerebral ischemia in patients with acute brain lesions: demonstration by xenon-enhanced CT.
PURPOSE: To examine the possibility that hyperventilation, commonly used to prevent or treat increased intracranial pressure in patients with acute brain lesions, may induce significant cerebral ischemia. METHODS: Local cerebral blood flow and vascular reactivity were measured before and after hyperventilation using xenon-enhanced CT in 12 patients with acute brain lesions. RESULTS: Five patients showed "paradoxical" reactivity (increased cerebral blood flow during hyperventilation) within the lesions. In five patients, hyperventilation induced ischemia in apparently normal regions of brain. In three patients, areas of luxury perfusion became ischemic during hyperventilation, while in three patients, lesions with moderate ischemia became more ischemic. Most patients showed more than one type of reactivity. CONCLUSIONS: These findings document hyperventilation-induced ischemia in acute brain lesions, and demonstrate that this phenomenon affects both injured and apparently intact areas of the brain. Further studies are required to determine the clinical significance of these pathophysiologic changes.