Zerovalent Rhodium and Iridium Silatranes Featuring Two-Center, Three-Electron Polar σ Bonds.

Species with 2-center, 3-electron (2c/3e ) σ bonds are of interest owing to their fascinating electronic structures and potential for interesting reactivity patterns. Report here is the synthesis and characterization of a pair of zerovalent (d ) trigonal pyramidal Rh and Ir complexes that feature 2c/3e σ bonds to the Si atom of a tripodal tris(phosphine)silatrane ligand. X-ray diffraction, continuous wave and pulse electron paramagnetic resonance, density-functional theory calculations, and reactivity studies have been used to characterize these electronically distinctive compounds.

Update: Mode of action (MOA) for liver tumors induced by oral exposure to 1,4-dioxane.

Previous work has shown that the weight of evidence supports the hypothesis that 1,4-dioxane causes liver tumors in rodents through cytotoxicity and subsequent regenerative hyperplasia. Questions regarding a lack of concordant findings for this mode of action (MOA) in mice have not been resolved, however. In the current work, a reanalysis of data from two chronic mouse cancer bioassays on 1,4-dioxane, one 13-week mouse study, seven rat cancer bioassays, coupled with other data such as 1,4-dioxane's negative mutagenicity, its lack of up-regulated DNA repair, and the appearance of liver tumors with a high background incidence, support the conclusion that rodent liver tumors, including those in mice, are evoked by a regenerative hyperplasia MOA.

Approaches for describing and communicating overall uncertainty in toxicity characterizations: U.S. Environmental Protection Agency's Integrated Risk Information System (IRIS) as a case study.

Single point estimates of human health hazard/toxicity values such as a reference dose (RfD) are generally used in chemical hazard and risk assessment programs for assessing potential risks associated with site- or use-specific exposures. The resulting point estimates are often used by risk managers for regulatory decision-making, including standard setting, determination of emission controls, and mitigation of exposures to chemical substances. Risk managers, as well as stakeholders (interested and affected parties), often have limited information regarding assumptions and uncertainty factors in numerical estimates of both hazards and risks.

Derivation of an occupational exposure limit for inorganic borates using a weight of evidence approach.

Inorganic borates are encountered in many settings worldwide, spurring international efforts to develop exposure guidance (US EPA, 2004; WHO, 2009; ATSDR, 2010) and occupational exposure limits (OEL) (ACGIH, 2005; MAK, 2011). We derived an updated OEL to reflect new data and current international risk assessment frameworks. We assessed toxicity and epidemiology data on inorganic borates to identify relevant adverse effects.

Mode of action analysis for liver tumors from oral 1,4-dioxane exposures and evidence-based dose response assessment.

1,4-Dioxane is found in consumer products and is used as a solvent in manufacturing. Studies in rodents show liver tumors to be consistently reported after chronic oral exposure. However, there were differences in the reporting of non-neoplastic lesions in the livers of rats and mice.

International spinal cord injury musculoskeletal basic data set.

Objectives: To develop an International Spinal Cord Injury (SCI) Musculoskeletal Basic Data Set as part of the International SCI Data Sets to facilitate consistent collection and reporting of basic musculoskeletal findings in the SCI population.

Setting: International.

Methods: A first draft of an SCI Musculoskeletal Basic Data Set was developed by an international working group.

Human health risks from mercury exposure from broken compact fluorescent lamps (CFLs).

Human health risk to infants/toddlers and adults was evaluated based on two exposure scenarios from compact fluorescent lamp (CFL) breakage; first in a room with no ventilation and no clean-up, and second in a room with adequate ventilation and clean-up. Concentration data from multiple exposure scenarios tested in a study by Stahler et al. (2008) were compared to human toxicity benchmarks to calculate hazard quotients.

Efficacy and safety study of arbaclofen placarbil in patients with spasticity due to spinal cord injury.

Study Design: Randomized, double-blind, placebo-controlled, two-period crossover.

Objectives: To evaluate the efficacy and safety of arbaclofen placarbil (AP) in patients with spasticity secondary to spinal cord injury (SCI).

Setting: United States and Canada.

Chronic oral inflammation and the progression of periodontal pathology in the third molar region.

Purpose: To assess the association between risk markers of chronic oral inflammation and changes over time in periodontal probing depth (PD) in the third molar region, the distal of a second molar, or around a third molar.

Subjects And Methods: The data from these analyses are part of a study of subjects enrolled with 4 asymptomatic third molars with adjacent second molars in an institutional review board-approved longitudinal trial. Full-mouth periodontal probing was conducted at enrollment and follow-up.

Change in third molar angulation and position in young adults and follow-up periodontal pathology.

Purpose: This study was designed to assess changes in third molar position and angulation in young adults and the resulting third molar periodontal probing (PD) status.

Patients And Methods: Data derived from patients with 4 asymptomatic third molars with adjacent second molars enrolled in an institutional review board approved longitudinal trial. Inclusion criteria for the trial dictated that patients be healthy and 14 to 45 years of age.

Progression of periodontal disease in the second/third molar region in subjects with asymptomatic third molars.

Purpose: To assess the change in periodontal status over time by periodontal probing depth (PD) in the third molar region.

Subjects And Methods: The data for these analyses are part of a study of subjects enrolled with 4 asymptomatic third molars with adjacent second molars in an institutional review board-approved longitudinal trial. Full mouth periodontal probing was conducted to determine periodontal status at baseline and follow-up.

Elevated plasma viscosity in extreme hemodilution increases perivascular nitric oxide concentration and microvascular perfusion.

We tested the hypothesis that high-viscosity (HV) plasma in extreme hemodilution causes wall shear stress to be greater than low-viscosity (LV) plasma, leading to enhanced production of nitric oxide (NO). The perivascular concentration of NO was measured in arterioles and venules and the tissue of the hamster chamber window model, subjected to acute extreme hemodilution, with a hematocrit (Hct) of 11% using Dextran 500 (n = 6) or Dextran 70 (n = 5) with final plasma viscosities of 1.99 +/- 0.

Intrathecal drug therapy using the Codman Model 3000 Constant Flow Implantable Infusion Pumps: experience with 17 cases.

Objectives: The objective of this study was to evaluate the accuracy, reliability, safety, and efficacy of the Codman Model 3000 Constant Flow Implantable Infusion Pump for intrathecal baclofen delivery as a therapeutic option for the treatment of severe spasticity. The distinctive features of this pump include a raised, easily palpable septum, a safety valve protecting the bolus pathway, no programmer needed, and no battery to fail.

Design: A total of 17 patients with spinal cord injury, multiple sclerosis, or cerebral palsy were implanted with this pump.

Efficacy and safety of tolterodine in people with neurogenic detrusor overactivity.

Objective: To compare tolterodine with oxybutynin and placebo in people with neurogenic detrusor overactivity.

Design: Prospective, randomized, double-blind, crossover trial plus open-label comparative stage.

Participants: Ten participants with neurogenic detrusor overactivity due to spinal cord injury or multiple sclerosis who used intermittent catheterization.

Relationship between erythrocyte aggregate size and flow rate in skeletal muscle venules.

In previous studies we showed that intravenous infusion of Dextran 500 in the rat causes blunting of the velocity profile of red blood cells in venules at low shear rates. To determine whether this blunting is associated with the formation of red blood cell aggregates, we measured the length and width of particles in the venular flow stream at systemic hematocrits up to 20% with a high-speed video camera and a new image analysis technique. Data were obtained at various shear rates under normal (nonaggregating) conditions as well as after infusion of Dextran 500.

Alpha adrenergic and serotonergic agents in the treatment of spastic hypertonia.

In the treatment of patients with problematic spasticity, it is important to consider the following steps: 1. Establish the functional impact of the spasticity. 2.

Erythrocyte margination and sedimentation in skeletal muscle venules.

Previous studies in skeletal muscle of the dog and cat have shown that venous vascular resistance changes inversely with blood flow and may be due mainly to red blood cell aggregation, a phenomenon present in these species. To determine whether red blood cell axial migration and sedimentation contribute to this effect, we viewed either vertically or horizontally oriented venules of the rat spinotrapezius muscle with a horizontally oriented microscope during acute arterial pressure reduction. With normal (nonaggregating) rat blood, reduction of arterial pressure did not significantly change the relative diameter of the red blood cell column with respect to the venular wall.

Surgical treatment of pressure ulcers: 20-year experience.

Objective: To review the outcomes of surgical management of spinal cord injury (SCI) patients with severe pressure ulcers and to examine likely risk factors for recurrence of pressure ulcers.

Design: A retrospective medical record review.

Setting: An SCI unit in a tertiary care facility.

Effect of erythrocyte aggregation on velocity profiles in venules.

A recent whole organ study in cat skeletal muscle showed that the increase in venous resistance seen at reduced arterial pressures is nearly abolished when the muscle is perfused with a nonaggregating red blood cell suspension. To explore a possible underlying mechanism, we tested the hypothesis that red blood cell aggregation alters flow patterns in vivo and leads to blunted red blood cell velocity profiles at reduced shear rates. With the use of fluorescently labeled red blood cells in tracer quantities and a video system equipped with a gated image intensifier, we obtained velocity profiles in venous microvessels (45-75 microm) of rat spinotrapezius muscle at centerline velocities between 0.

Diameter changes in skeletal muscle venules during arterial pressure reduction.

Previous studies in skeletal muscle have shown a substantial (>100%) increase in venous vascular resistance with arterial pressure reduction to 40 mmHg, but a microcirculatory study showed no significant venular diameter changes in the horizontal direction during this procedure. To examine the possibility of venular collapse in the vertical direction, a microscope was placed horizontally to view a vertically mounted rat spinotrapezius muscle preparation. We monitored the diameters of venules (mean diameter 73.

Walking index for spinal cord injury (WISCI): an international multicenter validity and reliability study.

Study Design: Construction of an international walking scale by a modified Delphi technique.

Objective: The purpose of the study was to develop a more precise walking scale for use in clinical trials of subjects with spinal cord injury (SCI) and to determine its validity and reliability.

Setting: Eight SCI centers in Australia, Brazil, Canada (2), Korea, Italy, the UK and the US.

BOLD MRI of the human cervical spinal cord at 3 tesla.

The feasibility of functional MRI of the spinal cord was investigated by carrying out blood oxygen-level dependent (BOLD) imaging of the human cervical spinal cord at a field of 3 T. BOLD imaging of the cervical spinal cord showed an average intensity increase of 7.0% during repeated exercise with the dominant hand with a return to baseline during rest periods.

Urinary and gastrointestinal systems medications.

This article reviews the medical management of the neurogenic bladder and bowel. The drugs discussed specifically affect detrusor instability, detrusor weakness, high urethral pressure, low urethral closure pressure, inflammatory cystitis, and chronic constipation.

Intrathecal drug therapy.

The direct application of drugs for non-hospitalized patients became a practical therapeutic modality with the advent of implantable drug delivery devices, or "pumps". This article describes the use of pumps for the intrathecal infusion of baclofen, morphine and clonidine.

Antispasticity medications.

The article illustrates a practical approach to the challenging management of problematic, generalized spasticity. Use of dose titration to achieve symptomatic relief is described. Currently approved pharmaceuticals used as antispasticity agents and muscle relaxants and other medications with antispasticity effects are reviewed.