Keratitis as a complication of bilateral, simultaneous radial keratotomy

During a one-month period, we examined four patients referred for evaluation of probable microbial keratitis after bilateral, simultaneous radial keratotomy. Each patient had midstromal infiltrates compatible with microbial keratitis that involved one or more of the radial incisions. In two patients the keratitis was bilateral. All patients had been treated empirically with antibiotic agents; superficial cultures with cotton-tipped applicators and corneal scraping by inserting a platinum spatula into the radial incisions were negative. Corneal biopsy of one patient disclosed gram-positive rods and culture of the biopsy specimen grew diphtheroids. The infiltrates gradually resolved over a period of several months with intensive antibiotic therapy. Sight-threatening infectious keratitis can occur after radial keratotomy, and we believe that simultaneous bilateral ocular surgery of any kind should be discouraged.     

Single myosin molecule mechanics: piconewton forces and nanometre steps

A new in vitro assay using a feedback enhanced laser trap system allows direct measurement of force and displacement that results from the interaction of a single myosin molecule with a single suspended actin filament. Discrete stepwise movements averaging 11 nm were seen under conditions of low load, and single force transients averaging 3-4 pN were measured under isometric conditions. The magnitudes of the single forces and displacements are consistent with predictions of the conventional swinging-crossbridge model of muscle contraction.     

The distribution of Nematospiroides dubius within the small intestine of laboratory mice

Recent reports have suggested the use of intravenous 201T1 (thallium-201) for myocardial imaging with the gamma scintillation camera. In order to better appreciate the possible utility of this agent in humans we examined its distribution and kinetics in 13 patients and in six mongrel dogs, three with experimental coronary artery occlusion. In addition, 201T1 was compared to 86Rb (rubidium-86) in 84 rats. In the rat heart, the concentration of 201T1 was 30% higher than that of 86Rb ten minutes after injection. Moreover, myocardium-to-blood ratios for 201T1 averaged 51:1, but only 32:1 for 86Rb ten minutes after administration. In the dog heart, the distribution of 201T1 paralleled that of radioiodinated (131I) albumin particles injected into the left atrium and, thus, appears to be related to regional blood flow. Its concentration in ischemic regions decreased to 32.3% of the normally perfused myocardium. In the patients with a recent or old myocardial infarction, areas of decreased 201T1 uptake were easily identified and corresponded in location to that by ECG. Repeat scans 24 hours after the initial injection showed a significant retention of 201T1 by the myocardium. 201T1 blood levels in humans 15 minutes after injection were low (averaging 1.06% +/- 0.41% SD of the total dose per liter) and these levels decreased with a biological half-life of 3.1 +/- 0.7 days. Twenty-four hour urinary excretion rates ranged from 0.6 to 6.5% of the total dose and appeared related to urinary flow and the concentation of 201T1 in blood. Because of the higher target to background ratios, 201T1 compares favorably with radioactive rubidium. 201T1 in diagnostic doses remained without detectable adverse effects and appears promising as an agent for visualizing abnormal regional myocardial perfusion in patients with coronary artery disease.     

Glucose and bicarbonate reabsorption in edematous dogs

Glucose and bicarbonate reabsorption were studied in dogs made edematour by aortocaval fistula (A-V dogs) and in sham-operated dogs. Following construction of the A-V fistula, there was a significant increase in body weight; glomerular filtration rate, renal plasma flow, hematocrit, and sodium excretion decreased significantly. Bicarbonate reabosorption was significantly higher in A-V than in sham dogs both during control and volume expansion. Volume expansion depressed bicarbonate reabsorption significantly in both groups. Glucose reabsorption fell following volume expansion in both groups; glucose reabsorption was significantly higher in A-V dogs than in sham dogs during control and volume expansion. Volume expansion led to a minimal increase in sodium excretion in A-V dogs when compared to the increase in the sham dogs. These data demonsttate that chronic sodium retention is associated with enhanced reabsorption of glucose and bicarbonate. The site in the neophron responsible for the increase in reabsorption of these substances cannot be determined with certainty based on these clearance studies although it is possible that proximal reabsorption may be enhanced in this model.     

Drying-induced stresses in porous bodies —an elastoviscoplastic model

The paper describes the application of the finite element method to the calculation of drying-induced stresses in capillary porous bodies, using an elastoviscoplastic stress-strain relationship. The method is illustrated by its application to the problem of drying of a clay brick. Stress distributions are shown at three distinct stages of the drying process, and at each stage the relaxation of the stresses due to plastic flow is indicated. Zones of potential failure are clearly seen, and hence geometry or rate of drying can be modified to avoid such failure.     

Source of cues for cue-dependent amnesia in rats.

In 2 experiments 54 Sprague-Dawley male albino rats were given extensive training in a complicated appetitive maze and then handled extensively for 7 days. On the 7th day of the retention interval some Ss were exposed to the "cognitive" learning cues of the maze and some were not. Immediately afterward Ss were given ECS or sham ECS. To the extent that cognitive learning cues are assumed to activate memory, the ECS impaired retrieval of memory only for those Ss which had the cues reinstated prior to ECS administration. It appears that memory must be active at the time of ECS in order to obtain retrieval deficits. In a 3rd experiment with 36 Ss the intensity of hunger drive, manipulated by the amount of prefeeding, was not a cue for memory activation and subsequent cue-dependent amnesia. Arousal is therefore not believed to be crucial for the effect. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Prognosis for total control of complex partial and secondarily generalized tonic clonic seizures. Department of Veterans Affairs Epilepsy Cooperative Studies No. 118 and No. 264 Group

When chaperonins GroEL and GroES are incubated under functional conditions in the presence of ATP (5 mM) and K+ (150 mM), GroEL-GroES complexes appear in the incubation mixture, that are either asymmetric (1:1 GroEL:GroES oligomer ratio) or symmetric (1:2 GroEL:GroES oligomer ratio). The percentage of symmetric complexes present is directly related to the [ATP]/[ADP] ratio and to the K+ concentration. Kinetic analysis shows that there is a cycle of formation and disappearance of symmetric complexes. A correlation between the presence of symmetric complexes in the incubation mixture and its rhodanese folding activity suggests some active role of these complexes in the protein folding process. Accordingly, under functional conditions, symmetric complexes are found to contain denatured rhodanese. These data suggest that binding of substrate inside the GroEL cavity takes place before the symmetric complex is formed.     

The relationship between the delayed improvement in ankle-brachial pressure index and changes in limb volume following balloon angioplasty for leg ischaemia

Occupational contact dermatitis to individual wood species from foreign countries, such as Asia, Africa, Central America, and South America, has been described. This report concerns the case of a domestic woodworker who developed allergic contact dermatitis shortly after beginning to work with multiple exotic woods. Patch testing with domestic and exotic wood fresh sawdust samples, 1% and 10% in petrolatum, yielded strong positive reactions to six exotic woods: zericote, pao ferro, cocobolo, becote, macassar ebony, and padauk. Later testing confirmed sensitivity to the allergenic quinonoid constituents in pao ferro (R-3,4-dimethoxydalbergione), cocobolo (obtusaquinone), and macassar ebony (macassar quinone).