Apparent diffusion coefficient and MR relaxation during osmotic manipulation in isolated turtle cerebellum.

The apparent diffusion coefficient (ADC) and relaxation times of water were measured by magnetic resonance imaging (MRI) in the isolated turtle cerebellum during osmotic cell volume manipulation. The aim was to study effects of cell volume changes, a factor in ischemia and spreading depression, in isolation from considerations of blood flow and metabolism. Cerebella were superfused at 12-14 degrees C with solutions ranging from 50-200% normal osmolarity. Hypotonic solutions, which are known to cause cell swelling, led to reductions of ADC and increases of T(2), while hypertonic solutions had the opposite effect. This supports the concept that ADC varies with the extracellular space fraction and, combined with published data on extracellular ion diffusion, is consistent with fast or slow exchange models with effective diffusion coefficients that are approximately 1.7 times lower in intracellular than in extracellular space. Spin-spin relaxation can be affected by osmotic disturbance, though such changes are not seen in all pathologies that cause cell swelling.

A kinetic microassay for glutathione in cells plated on 96-well microtiter plates.

We describe a modified enzymatic, kinetic, glutathione microassay based on the original macroassay described by Tietze and modified by Anderson. It is coupled with the Triton X-100 lysis and an acid extraction that can be performed in 96-well microtiter plates. The microassay can be read in a microplate reader equipped with a standard 405 nm filter. Intracellular glutathione levels are not significantly different when comparing the proposed Triton X-100 lysis and acid extraction method from those found with the cellular homogenization and acid extraction method typically employed. By combining a rapid sample extraction method, which can be done on the microtiter plate, with an assay based on the technology of a microplate reader, we have devised a rapid, reproducible, inexpensive and easy to use GSH microassay that can process several hundred samples daily and will be useful in studies where many replicate samples are required. We have successfully used this method to monitor glutathione status in a human cell line exposed to organochlorine pesticides and cells exposed to naturally occurring mixtures of metals extracted from aquatic sediments.

Survival of patients undergoing Nd:YAG laser therapy compared with Nd:YAG laser therapy and brachytherapy for malignant airway disease.

Brachytherapy in combination with Nd:YAG laser therapy may add to the duration of survival of the palliative period when compared with laser alone. A retrospective study of patients with inoperable squamous cell carcinoma (SCC) was undertaken to determine if there was a difference in survival between those patients treated with Nd:YAG laser alone and those treated with Nd:YAG laser and brachytherapy. Twenty-two patients were treated with brachytherapy for malignant airway disease at our institution of which 13 had SCC. All patients had previously received treatment with Nd:YAG laser for exophytic disease. Survival was compared with those patients treated with Nd:YAG laser alone for SCC involving the airway. There was no statistical difference between the two groups with regard to age. The duration of survival of patients with SCC of the airway from the first Nd:YAG laser treatment was determined. A significant difference between those patients treated with Nd:YAG laser alone and those patients treated with combined therapy was found (p < 0.001). Brachytherapy may potentiate the duration of survival in patients with SCC involving the airway compared to palliation with Nd:YAG laser alone.

Acute postdisaster psychiatric disorders: identification of persons at risk.

This study examined the prevalence of four psychiatric disorders--posttraumatic stress disorder, major depression, generalized anxiety disorder, and alcohol abuse/dependence--in survivors of a jet plane crash into a hotel. Forty-six subjects were interviewed with the Diagnostic Interview Schedule/Disaster Supplement within 4-6 weeks of the event. More than half of the subjects met criteria for a psychiatric disorder after the disaster. More than two-thirds of the cases of acute postdisaster psychiatric disorders were predicted by identifying the subjects who had predisaster psychiatric histories. Predisaster psychiatric disorder predicted postdisaster psychopathology with a sensitivity of 72% and a specificity of 90%.

Controlled trial of azathioprine and cyclosporin to prevent anti-HLA antibodies due to third-party transfusion.

The beneficial effect of elective transfusion on renal allograft survival must be weighed against the risks of sensitisation. We report a randomised controlled trial in which patients in end-stage renal failure who were non-parous and not previously transplanted or transfused, were entered in a transfusion protocol during which one group received no drugs (controls), one received azathioprine, and one received cyclosporin. Each group was given three identical transfusions of leucocyte-enriched fresh blood at 2-3 week intervals. The transfused blood was of known HLA type and donor/recipient pairs were completely mismatched. Sensitisation rates were assessed by T and B cell cross-matches between donor and recipients and by the screening of all sera against lymphocytes from 40 random donors. Fifty-one patients have completed the protocol, 20 in the control group, 12 in the azathioprine group, and 19 in the cyclosporin group. The sensitisation rate in the control group was 30%, occasionally of high titre, and persistent. In the azathioprine group, 25% developed anti-HLA antibodies and reactivity was of high titre and was broadly specific. Sensitisation in the cyclosporin group was 10%, was narrowly specific, reacting with only 10% of a panel, and was transient. There was no difference in graft survival between the groups. We conclude that cyclosporin therapy concurrent with third-party transfusion reduces the incidence, titre, and duration of sensitisation.

Morphometric analysis of the forebrain anomalies in the delayed Splotch mutant embryo.

The early development of delayed Splotch mouse embryos was examined histologically using scanning electron microscopy and morphometric techniques. Embryos obtained from matings of mice heterozygous for the delayed Splotch gene exhibited a high incidence of lumbosacral (25%) or cephalic (7%) neural tube defects. The lumbosacral neural tube defects extended from the posterior neuropore region to the tip of the tailbud; cephalic neural tube closure defects were found in the hindbrain and midbrain regions. The frontal region of affected embryos was abnormal in that it was reduced in size, particularly in the developing midface. Histologically, the forebrain region of affected embryos appeared reduced, and the luminal surface of the neuroepithelium was often irregular and infolded. To quantify these alterations and to determine their contribution to the final form of the region, size and areal measurements were recorded and served as input for principal component and cluster analytic techniques. In affected embryos, significant reductions were found in lumen size, in neuroepithelial area but not thickness, and in overall area of forebrain but not hindbrain. Principal component analysis of data from unaffected embryos produced two factors, one containing hindbrain variables and the second forebrain variables; for the affected embryos, three factors were extracted. The first loaded on variables that measured the thickness and area of the neuroepithelium, the second on forebrain variables, and the third on hindbrain variables. Factor scores were then generated from a pooled analysis of normal and affected cases and were analyzed using cluster analysis. Three clusters were identified: one contained eight affected embryos with cephalic neural tube defects; another contained nine affected embryos with lumbosacral neural tube defects and five normal embryos; and the final cluster contained ten unaffected embryos. These results suggest a major role of the delayed Splotch gene on the neuroepithelium itself and support the suggested role of cerebrospinal fluid pressure in normal forebrain histogenesis.

Acute Quadriplegia Following the Use of Progressive Resistance Exercise Machinery.

In brief: This case report describes a 26-year-old female fitness instructor in excellent health who suffered the acute onset of permanent quadriplegia only a few minutes after using progressive resistance exercise devices. She began her workday as she usually did-with a light workout of low-resistance exercise that lasted about 20 minutes. The onset of quadriplegia may have been a tragic coincidence or may have been related to her workout in a way that remains unexplained. Several possible causes of her condition, which was diagnosed as spinal apoplexy of an unknown cause, are discussed.

The congenital cavus foot. A follow-up report.

Congenital cavus feet are not commonly related to central nervous system disease or associated with other significant congenital anomalies. The authors believe that the congenital variety of cavus foot is probably the most common etiology of cavus deformity, although it is usually noted only in later life when it becomes symptomatic. The vast majority of these feet can be managed conservatively; only rarely is surgical intervention warranted. Early recognition of the deformity and appropriate treatment is important. The Hibbs angle is a useful method of measuring the cavus deformity and can be employed in determining the degree of the deformity.

Purification of desmin from adult mammalian skeletal muscle.

A method has been developed for preparation of purified desmin from mature mammalian (porcine) skeletal muscle. A crude desmin-containing fraction was prepared by modification of procedures used for isolation of smooth-muscle intermediate-filament protein [Small & Sobieszek (1977) J. Cell Sci. 23, 243-268]. The desmin was extracted in 1 M-acetic acid/20 mM-NaCl at 4 degrees C for 15h from the residue remaining after actomyosin extraction from washed myofibrils. Successive chromatography on hydroxyapatite and DEAE-Sepharose CL-6B in 6M-urea yielded desmin that was routinely more than 97% 55 000-dalton protein and that had no detectable actin contamination. Removal of urea by dialysis against 10mM-Tris/acetate (pH 8.5)/1 mM dithioerythritol and subsequent clarification at 134 000 g (rav. 5.9 cm) for 1 h results in a clear desmin solution. Dialysis of purified desmin against 100 mM-NaCl/1 mM-MgCl2/10 mM-imidazole/HCl, pH 7.0, at 2 degrees C resulted in the formation of synthetic desmin filaments have an average diameter of 9-11.5 nm. The present studies demonstrate that the relatively small amount of desmin in mature skeletal muscle can be isolated in sufficient quantity and purity to permit detailed studies of its properties and function. Although 10nm filaments have not been unequivocally demonstrated in mature muscle in vivo, that the purified skeletal-muscle desmin will form 10 nm filaments in vitro lends support to their possible existence and cytoskeletal function in mature skeletal-muscle cells.

Effect of pressure treatments on the mechanical properties of pre- and post-rigor meat.

Pressure-heat treatment of beef semitendinosus samples post-rigor gave shear and tensile results similar to those obtained with pressure treatment pre-rigor. Post-rigor pressure-heat treatment did not affect the contraction state, unlike pre-rigor pressure treatment which caused samples to contract by about 40%. Maximum tenderizing effect by pressure-heat treatment (150 M Nm(-2) at 60°C for 30 min) was achieved when samples were heated at 45°C for 45-180 min immediately before application of the treatment. As the pre-pressurization temperature was increased, the duration of heating became more critical until at temperatures ≥ 60°C the effects of subsequent pressure-heat treatment became very small. Pressure-heat treated samples did not show the increase in shear force values for cooking temperatures ≥ 60°C associated with myofibrillar hardening. It was concluded that pressure-heat treatment primarily affected the myofibrillar structure.

Some effects of pressure treatment on actomyosin systems.

Natural actomyosin, actin and myosin, have been pressurized at up to 150 MN/m2 for 1 h at 0 degrees C and examined 3-5 h later. Pressurization of myosin resulted in the formation of aggregates with a molecular weight approximately that expected for a dimer, whereas with F-actin depolymerization occurred. With actomyosin, a gel to sol transition was promoted. Viscosity and light-scattering measurements indicated that pressurization results in a large measure of disaggregation of actomyosin in solution. Pressurization of actomyosin resulted in a greater decrease in the calcium-sensitive, than in the calcium-independent, Mg2+ ATPase activity. The Ca2+ and K+-EDTA ATPase activities of myosin were inhibited to about the same extent.