Tissue fixation security in transosseous rotator cuff repairs: a mechanical comparison of simple versus mattress sutures

The primary purpose of this investigation was to compare tissue fixation security by simple sutures versus mattress sutures in transosseous rotator cuff repair. These two repair techniques were each performed in 17 human cadaver shoulders, with two bone tunnels being used for the repair by two simple sutures and two other bone tunnels being used for the repair by one mattress suture. The repairs were loaded to failure in a servohydraulic materials test system. Rotator cuff repair by simple sutures was found to be significantly stronger than repair by mattress sutures (P = .0007). The average ultimate load to failure for the simple suture construct (189.62 N) was 39.72% greater than that for the mattress suture construct (135.71 N). Most of the failures occurred by suture breakage at the knot. Load-sharing by multiple suture tails and multiple knots in the simple suture configuration likely contributed to its superior strength characteristics compared with the mattress suture configuration.     

Shear numbers of protein beta-barrels: definition refinements and statistics

The original definition of shear number for a beta-barrel is not unique if it contains one or more uneven beta-bulges. We define the shear number of a beta-barrel as the minimal change of residue numbers in the backbone direction for all closed paths on the beta-barrel. We also discuss how to overcome some computational difficulties. It is pointed out that some closed beta-sheets should not be considered as beta-barrels. The pertinent statistics obtained from a representative list of the Protein Data Bank entries are summarized. All beta-barrels have positive shear numbers, i.e. they are right-twisted. The shear numbers of most beta-barrels are even, but exceptions do exist. The sizes of beta-ladders in a beta-barrel vary significantly. Most beta-barrels contain uneven beta-bulges, which may have important biological functions.     

Diminished levels of insulin-like growth factor-I in lungs in streptozotocin-induced diabetes: relation to nutritional status and growth

It is yet unknown whether the impaired nutritional status of streptozotocin-induced diabetic rats influences changes in levels of insulin-like growth factor-I (IGF-I) in this experimental model of diabetes. To explore this possibility, simultaneous studies were undertaken of rats made diabetic by streptozotocin (75 mg/kg body wt, intraperitoneally) and undernourished control rats with similar somatic growth rate (determined by body weight gain), in comparison with normal controls. Serum IGF-I levels were diminished in the untreated diabetic and undernourished control animals, but more so in the diabetic group. Lung IGF-I levels (per lung and per lung DNA) and DNA contents were diminished to similar degrees in the untreated diabetic animals and the undernourished control group. Lung dry weights of the diabetic rats were greater than those of the undernourished control group, such that lung IGF-I/100 mg tissue dry wt in the former was significantly lower than in the latter group. Insulin treatment of the diabetic rats restored their body weights, serum and lung IGF-I levels, and DNA contents to normal control values. Lung IGF-I levels in the diabetic rats correlated strongly with serum glucose (r = .75) and body weight (r = .79), and moderately with lung weight (r = .43) and lung DNA (r = .58). These findings suggest that the diminished lung IGF-I levels in streptozotocin-induced diabetes may be related to the impaired nutritional status and/or somatic growth of the experimental animals, and that this relationship may be responsible, at least in part, for the diminished lung cellular proliferation observed in experimental diabetic animals.     

Economic analysis of tirilazad mesylate for aneurysmal subarachnoid hemorrhage. Economic evaluation of a phase III clinical trial in Europe and Australia

This study used data from a multinational phase III randomized, double-blind, vehicle-controlled trial to evaluate the cost-effectiveness of tirilazad mesylate (Freedox) in the treatment of aneurysmal subarachnoid hemorrhage. In men, therapy with 6 mg/kg per day of tirilazad mesylate was associated with significantly increased survival, increased cost of care, and ratios of cost per death averted that compare favorably with the ratios of other life and death interventions. In women, it appeared to have no effects on costs or survival. Further clinical studies may provide additional information about the cost-effectiveness of this intervention.     

Optic neuropathy resembling normal-pressure glaucoma in a teenager with congenital macrodiscs

We report a unique case of a renal transplant patient with a long-term nonprogressive human immunodeficiency virus type-1 (HIV-1) infection and who is asymptomatic despite sustained immunosuppression. Renal function is normal, and HIV infection was probably acquired through blood transfusion before the transplant. Nonprogression may be due either to an effective immune control of HIV replication or to particular genetic aspects of the virus. Several virological investigations were carried out to verify if she is infected with an attenuated virus strain. Results show an unusual combination of high and stable CD4 count, ongoing viral replication and elevated viral loads. Attempts to isolate the virus from plasma were unsuccessful, but isolation was possible from peripheral blood mononuclear cells, and the virus was shown to be non-syncytium-inducing. Sequence analysis of the nef gene revealed no mutation. This exceptional lack of progression of HIV infection under immunosuppressive therapy requires further investigation.     

Differential expression and distribution of focal adhesion and cell adhesion molecules in rat hepatocyte differentiation

The present study has examined the distribution of axons of differing sizes in the optic pathway of the ground squirrel. Axon diameters were measured from electron micrographs at various locations across sections of the optic nerve and tract, and total distributions and numbers were estimated. In both the nerve and tract, roughly 1.2 million optic axons were present. The population of optic axons had a unimodal size distribution, peaking at 0.9 microm in diameter and having an extended tail toward larger diameters. Local axon diameter distributions in the optic tract indicated distinct (though partially overlapping) axon diameter classes, including one of fine sizes peaking at 0.8-0.9 microm, a second of medium sizes peaking around 1.7-1.8 microm, and a third composed of the larger fibers with diameters up to 4.8 microm. The fine-caliber axons were found at all locations in the tract, and were the only axons present immediately adjacent to the pia, while the medium- and coarse-caliber axons were found at deeper locations. Curiously, the larger axons were found primarily in the medial parts of the tract, where axons from the dorsal retina normally course. A similarly restricted distribution of the larger axons was observed in the dorsotemporal parts of the optic nerve, suggesting that this difference in the tract may relate to an asymmetric distribution of ganglion cells on the retina giving rise to these axons. Measurements of axonal size taken within the optic fiber layer in dorsal and ventral parts of the retina confirmed this asymmetry, consistent with previous demonstrations of soma size differences in the dorsal versus ventral retina. The partial segregation of axons by size in the optic tract of the ground squirrel then reflects both the asymmetric distribution of retinal ganglion cell classes and the chronotopic reordering of optic axons that occurs within the chiasmatic region.     

Premedication with oral midazolam in children--an assessment of psychomotor function, anxiolysis, sedation and pharmacokinetics

We studied 30 children, aged 4 to 12 years, undergoing elective circumcision, premedicated with midazolam 0.5 mg.kg-1 and atropine 0.02 mg.kg-1 by mouth. A modified postbox test and the coding component of the Wechsler intelligence scale (WISC-R) was used to assess the preoperative effect of premedication on psychomotor function. Mood and sedation were also scored and related to serum midazolam concentrations. The children showed a significant decline in psychomotor performance 30 and 60 minutes after premedication when compared with their best unmedicated performance recorded the previous evening. This decline in psychomotor performance was only weakly associated with serum midazolam concentrations (r = 0.1). The postbox toy ratio is a suitable measurement of psychomotor performance in children because of its simplicity and ease of use in the clinical environment, although it may suffer the "test-retest" limitations of similar types of assessment. The sedative and anxiolytic effects of midazolam provide a quiet environment for a smooth induction of anaesthesia.