The prevalence of autonomic neuropathy in the primary glaucomas

The results of systemic autonomic nerve function studies in patients with closed-angle glaucoma and ocular hypertension are reviewed. Autonomic neuropathy has been demonstrated in 58% of patients with closed-angle glaucoma and 42% of ocular hypertensive subjects, with significantly increased prevalence in ocular hypertensives with narrow iridocorneal angles. The implications are discussed, with particular reference to the pathogenesis of raised intraocular pressure.     

Comparative dermal carcinogenesis of shale and petroleum-derived distillates

Ten test materials derived from petroleum or hydrotreated shale oils were applied 3 times/week for up to 105 weeks to the shaved skin of 25 male and 25 female C3H/HeN mice per group. Mineral oil and benzo(a) pyrene (0.15%) were control materials. Clinical observations were recorded during the study. At death, histopathologic examination was conducted on skin, internal organs and any gross lesions. Exposures to some materials were ended midway in the study due to severe irritation. Chronic toxicity of all materials was limited to inflammatory and degenerative skin changes. Significant increases over control incidence of skin tumors (squamous cell carcinoma and fibrosarcoma) occurred with both petroleum and shale-derived naphtha (21%, 50%), Jet A (26%, 28%), JP-4 (26%, 50%), and crude oils (84%, 54%). Severely hydrotreated shale oil and petroleum and shale-derived diesel distillates were not considered tumorigenic. Results indicate that toxicity of comparable petroleum and shale-derived fractions was qualitatively similar and confirm earlier findings that hydrotreating reduces or eliminates carcinogenicity of raw shale oil.     

High alveolar surface tension increases clearance of technetium 99m diethylenetriamine-pentaacetic acid.

The effect of high alveolar surface tension on alveolar epithelial permeability was studied in anesthetized closed-chest mongrel dogs. Alveolar surface tension was elevated by displacement of pulmonary surfactant from the alveolar hypophase by the aerosolized detergent dioctyl sodium sulfosuccinate (OT). After measurement of baseline hemodynamics, arterial blood gases, and airway pressure, the dogs were separated into groups: Group I inhaled a 1% solution of OT (15 mg/kg) in a vehicle of equal parts saline and ethanol; group II inhaled the same volume of vehicle without OT. The pulmonary clearance of technetium 99m diethylenetriamine-pentaacetic acid (99mTc-DTPA) (half-time in minutes) was studied immediately after aerosol (OT and vehicle) delivery and compared with that of historical control values. No change was seen in arterial blood gases and airway pressure after vehicle inhalation, whereas OT caused a marked fall in arterial oxygen tension and increase in airway pressure. Vehicle inhalation effected only a slight increase in DTPA clearance, whereas OT significantly reduced half-time over control and group II. These data suggest that high alveolar surface tension increases alveolar epithelial permeability.     

Calcium decreases transparency of homogenate from lens cortex and has no effect on nucleus

We studied the effects of calcium on transparency in homogenates of cortical and nuclear cells from calf lenses. Calcium was mixed into samples of homogenate to final concentrations between 0 and 50 mM and the transparency of the calcium-treated homogenates was measured using laser transmittance. In the presence of 10 mM calcium, the transmittance of cortical homogenate decreased 50% while the nuclear homogenate lost less than 4% transmittance after 24 h at 37 degrees C. To better understand the contribution of cytoplasm and membranes to opacity, the nuclear and cortical homogenates were centrifuged to separate membranes from the cytoplasm. When 10 mM calcium was added to cortical homogenate which was then centrifuged, the transmittance of the membrane fraction decreased nearly 60%, while the fraction without membrane decreased only 10%. The strong effect of calcium on the membrane fraction was accompanied by an increase in specific gravity of membranes from 1.23 to 1.32. Ten- and 20 mM calcium had no effect on transparency of membranes or cytoplasm separated from nuclear homogenate, and 50 mM calcium produced only a slight opacity. The results indicate that an effect on membrane-protein interactions may be important in the loss of transparency produced by calcium in cells of lens cortex.     

Diagnostic accuracy of progressive supranuclear palsy in the Society for Progressive Supranuclear Palsy brain bank.

Diagnostic accuracy has been addressed previously for Parkinson's disease in a brain bank collection, but accuracy of progressive supranuclear palsy (PSP) has not been addressed in a similar setting. Clinical and genetic features of pathologically confirmed cases of PSP were compared with misdiagnosed cases to determine ways to improve diagnostic accuracy. Medical records were reviewed for 180 cases sent to the Society of Progressive Supranuclear Palsy Brain Bank that had standardized neuropathologic evaluations as well as determination of apolipoprotein E and tau genotypes. Of the 180 cases studied, 137 had PSP and 43 had other pathologic diagnoses. Corticobasal degeneration (CBD), multiple system atrophy (MSA), and diffuse Lewy body disease (DLBD) accounted for 70% of the misdiagnosed cases. History of tremor, psychosis, dementia, and asymmetric findings were more frequent in misdiagnosed cases. The frequency of H1 tau haplotype (93 vs. 80%) and H1H1 genotype (86 vs. 66%) were significantly greater and APOE epsilon4 carrier state was significantly less (17 vs. 41 %) in PSP compared with misdiagnosed cases. Pathologic evaluation of clinically diagnosed PSP remains important for definitive diagnosis, and CBD, MSA, and DLBD are the disorders most likely to be misdiagnosed as PSP. Tremor, psychosis, early dementia, asymmetric findings, absence of H1 haplotype, and presence of APOE epsilon4 should raise questions about a diagnosis of PSP.     

Techniques of splenic preservation using fibrin glue

Fibrin glue (FG) was used to achieve hemostasis of 16 splenic injuries in 14 patients. The etiologies of injury included five gunshot wounds, two stab wounds, four iatrogenic injuries, and five patients with blunt splenic trauma. The intraoperative blood loss averaged 1.8 +/- 2.4 (SD) liters and patients were transfused 3 +/- 2 units of blood perioperatively. The amount of FG required to achieve splenic hemostasis averaged 11 +/- 8 ml and varied directly with the grade of injury. One patient with a splenic hilar vascular injury (Grade V) underwent splenectomy following failure to achieve complete hemostasis despite the use of 25 ml of FG. All other splenic injuries were successfully managed using less than 25 ml of FG. Postoperative computerized tomographic (CT) scanning, performed in ten patients, was negative for rebleeding or abscess formation. The overall splenic salvage rate was 86%. FG was effective in achieving hemostasis of both superficial and deep splenic injuries. Its use as an adjunct in trauma surgery should result in increased splenic salvage rates compared with that obtained using conventional surgical techniques.     

Dual Effects of Hexanol and Halothane on the Regulation of Calcium Sensitivity in Airway Smooth Muscle

Background: Contraction of airway smooth muscle is regulated by receptor-coupled mechanisms that control the force developed for a given cytosolic calcium concentration (i.e., calcium sensitivity). Halothane antagonizes acetylcholine-induced increases in calcium sensitivity by inhibiting GTP-binding (G)-protein pathways. The authors tested the hypothesis that hexanol, like halothane, inhibits agonist-induced increases in calcium sensitivity in airway smooth muscle by inhibiting G-protein pathways.

Methods: Calcium sensitivity was assessed using [alpha]-toxin-permeabilized canine tracheal smooth muscle. In selected experiments, regulatory myosin light chain phosphorylation was also determined by Western blotting in the presence and absence of 10 mm hexanol and/or 100 [mu]m acetylcholine.

Results: Hexanol (10 mm) and halothane (0.76 mm) attenuated acetylcholine-induced calcium sensitization by decreasing regulatory myosin light chain phosphorylation during receptor stimulation. Hexanol also inhibited increases in calcium sensitivity due to direct stimulation of heterotrimeric G-proteins with tetrafluoroaluminate but not with 3 [mu]m GTP[gamma]S, consistent with prior results obtained with halothane. In contrast, in the absence of receptor stimulation, both compounds produced a small increase in calcium sensitivity by a G-protein-mediated increase in regulatory myosin light chain phosphorylation that was not affected by pertussis toxin treatment.     

An assessment of the characteristics of n-type diodes for use in electron beam radiotherapy.

Diodes are now commercially available for use in electron beams. This paper aims to assess their response and limitations under different clinical conditions. Parameters considered were applicator factors, focus skin distance (FSD), angle of incidence, and temperature dependence. The beam perturbation was also measured. The beam energies used varied from 5 to 17 MeV. Applicator factors, measured at the surface of a phantom, differed by up to 7% compared with ion chamber measurements at Dmax. Similarly, large differences were found in FSD dependence. The temperature dependence was found to be approximately double the manufacturer's specification at 0.7% per degree Centigrade and the angular dependence was within the specification of +/- 2% for angles of +/- 30 degrees. The beam perturbation was measured as a maximum of 25% for 5-MeV electrons. The measurements were compared to other published data but this is highly dependent on the methodology employed. It was concluded that the diodes could be used in some circumstances, but only if used with extreme caution. An extensive set of commissioning measurements would be required before introducing the diodes into use clinically.