Cerebrovascular and metabolic perturbations in delayed heavy charged particle radiation injury

Focal heavy charged particle irradiation of the rabbit brain created defined lesions which were observable by nuclear magnetic resonance (NMR) and positron emission tomography (PET) imaging techniques. The lesions appeared approximately 9-11 months after left partial hemibrain irradiation with 30 Gy (230 MeV/u helium ions), and were restricted to the white matter tracts and deep perithalamic and thalamic regions. 82Rubidium PET and Gadolinium DTPA enhanced NMR imaging were used to detect blood-brain barrier perturbations. 18Fluordeoxyglucose PET studies demonstrated widespread decreases in cerebral glucose uptake in the cortex and thalamus of the irradiated hemisphere. NMR and PET imaging results correlated well with histological findings. Rabbits irradiated with 15 Gy did not demonstrate any abnormalities in the brain with sequential NMR scans through 14 months post-irradiation.     

Administration of kainic acid and colchicine alters mu and lambda opiate binding in rat hippocampus

Quantitative in vitro autoradiography was used to assess the effects of kainic acid (KA) and colchicine (COL) on mu and lambda opiate binding in the rat hippocampus. Rats were treated with either systemic KA, a neurotoxin that damages CA3 pyramidal cells and causes seizures and wet-dog shakes, or intrahippocampal COL to destroy dentate granule cells and their mossy fibers, or both toxins. Moderate levels of mu binding were detected in the pyramidal layer and in the stratum lacunosum-moleculare; binding was greater in the ventral hippocampus. Levels of mu binding were markedly increased in all regions 48 h after treatment with KA. Two weeks after COL treatment, there was a modest decrease in mu binding; COL plus KA gave results similar to COL alone. Dense lambda binding was present over the mossy fibers in the stratum lucidum, but was absent over the pyramidal layer. In contrast to mu binding, lambda binding was greater in the dorsal hippocampus. KA alone had little effect on lambda binding, whereas COL alone caused large decreases. KA plus COL caused even larger decreases in lambda binding, to as much as 85% below control. These results demonstrate that mu and lambda binding are localized to different parts of the hippocampus, respond differently to neurotoxin lesions, and likely serve different roles in this brain region. The number of mu sites is responsive to the release of enkephalin; these receptors appear to be linked to opiate-induced hippocampal seizure activity, especially wet-dog shakes. Lambda sites may serve as autoreceptors on mossy fibers.     

The factor of magnification in mammography

The last generation of mammographic equipment allows mammography to be performed with direct magnification techniques, thanks to such technical features as microfocus, high focus-film distance, high-power generators. The authors compared the diagnostic yield of two different equipment sets, with 1.4x and 2x magnification respectively, and verified the utility of magnification radiography. A significant reduction was obtained in questionable diagnoses (42 to 18) in a group of 63 patients, with no evidence of substantial differences in the diagnostic yield of the images obtained with different magnification ratios. An objective analysis of the system resolution power privileges 2x magnification ratio, which however implies an increase in the average dose to the breast. The use of faster recording systems reduces the dose by 50%, though maintaining good image quality.     

Behavioral treatment of angina-like chest pain in patients with hyperventilation syndrome

The hyperventilation syndrome is present in as many as 50% of patients with non-cardiac chest pain. This study evaluated a behavioral treatment of this disorder in three adult females. They had long histories of chest pain and were documented to be free of coronary artery disease. Each subject met the DSM-III-R diagnostic criteria for an anxiety disorder. Following treatment, all subjects showed a marked decrease in the frequency and intensity of chest pain episodes and in the frequency of shortness of breath episodes. Two subjects maintained their progress at one-year follow-up. The results lend support to the efficacy of controlled breathing and relaxation training for the treatment of hyperventilation-related chest pain and to the inclusion of a hyperventilation provocation test in the diagnosis of the syndrome as well as its role in changing cognitions regarding cardiac status. Also discussed is the rationale for treating hyperventilation related chest pain in a medical care setting.     

Blood alcohol level among emergency room patients: a multivariate analysis

This article examines the distribution of positive blood alcohol levels (BALs) among emergency room patients and the relationship between intoxication and other variables. Approximately one-quarter of the 640 subjects had positive blood alcohol levels and 16.3% had BAL readings above 0.10%, the legal limit for operating a motor vehicle in most states. Chi-square tests and logistic regression analysis indicated a significant relationship between employment status, gender, educational attainment, age and BAL. There were no significant racial differences. Analysis of the role of the presenting problem with BAL revealed that being involved in an accident was significantly predictive of a high BAL in a multivariate context. However, patients presenting with psychiatric problems had overall higher levels of intoxication than other patients. These findings have major implications for public policy formulation vis-à-vis public health delivery.     

Cranial nasal bone grafts

Reconstitution of the nasal scaffolding with maintainence of soft tissue proportions either following severe facial trauma or as a sequela to aesthetic rhinoplasty misadventures frequently is best achieved using the stability afforded by bone grafts. Split cranial bone grafts offer many advantages and may be the donor site of choice, and may even allow such surgery to be performed on an outpatient basis in some cases. The use of miniplate or screw osteosynthesis, now commonly accepted as a superior technique in craniomaxillofacial procedures, may simplify fixation of these calvarial nasal bone grafts with an apparent decrease in the risk of resorption.     

Morphological findings during retinal development and maturation in hereditary rod-cone degeneration in Abyssinian cats

The sequence of structural changes involved in postnatal photoreceptor differentiation, maturation and early degeneration was studied in young Abyssinian cats and kittens with hereditary rod-cone degeneration and compared to maturation in normal controls. In affected cats the earliest change seen was disorientation of outer segment discs in the majority of the rods, while other rods appeared to develop and mature normally. Such disorientation of discs (at oblique angles or parallel to the longitudinal axis of the outer segment, or whorls of discs) is considered as 'immaturity', since controls also showed a substantial number of disoriented rod outer segment discs at this young age. At postnatal day 35 the difference between affected animals and controls was marked with a high frequency of immature appearing rod outer segment discs in affected animals, while all rod outer segment discs were adult-like and arranged in an orderly manner in controls. Cones seemed unaffected at this age. More severe changes in affected rod outer segments in the form of disintegration of discs (vacuolization and clumping of disc material, or formation of debris), which we consider to represent degeneration, were first observed at the time when retinal maturation normally occurs in the cat, i.e. 150 days postnatally. Subsequently a drop-out of rods was seen, primarily of rods with disoriented and disintegrated outer segment discs, followed by a slow, progressive degeneration of rods that had developed and matured normally. Cones appeared normal during the time of retinal development and maturation and it was not until the age of 2-3 years (Narfstr?m and Nilsson, 1986, Incest. Ophthalmol, Vis. Sci. 27, 1569-76) that degenerative changes were seen also in cones.     

Outflow of aqueous humor following cyclodialysis or ciliochoroidal detachment in rabbit

Cyclodialysis and ciliochoroidal detachment were performed in three eyes of three rabbits and in three eyes of another three rabbits, respectively. After aspiration of the aqueous humor, 0.1 ml of 10% sodium fluorescein was injected intracamerally, and the eyeball was enucleated between 30 minutes and one hour after injection and prepared for fluorescence microscopy. Sodium fluorescein concentrations in the supraciliary space were much greater in the group with cyclodialysis or ciliochoroidal detachment than in the normal control group. These results suggest that (1) in the eye with cyclodialysis, the aqueous humor may freely gain access to the supraciliary space through the cleft between the anterior chamber and the supraciliary space and then be removed rapidly and (2) in the eye with ciliochoroidal detachment, the aqueous humor may pass through the uveoscleral outflow pathway.