Common questions about chronic low back pain.

More than 30% of U.S. adults report having experienced low back pain within the preceding three months. Although most low back pain is nonspecific and self-limiting, a subset of patients develop chronic low back pain, defined as persistent symptoms for longer than three months. Low back pain is categorized as nonspecific low back pain without radiculopathy, low back pain with radicular symptoms, or secondary low back pain with a spinal cause. Imaging should be reserved for patients with red flags for cauda equina syndrome, recent trauma, risk of infection, or when warranted before treatment (e.g., surgical, interventional). Prompt recognition of cauda equina syndrome is critical. Patient education should be combined with evidence-guided pharmacologic therapy. Goals of therapy include reducing the severity of pain symptoms, pain interference, and disability, as well as maximizing activity. Validated tools such as the Oswestry Disability Index can help assess symptom severity and functional change in patients with chronic low back pain. Epidural steroid injections do not improve pain or disability in patients with spinal stenosis. Spinal manipulation therapy produces small benefits for up to six months. Because long-term data are lacking for spinal surgery, patient education about realistic outcome expectations is essential.

CT findings and long-term mortality after pulmonary embolism.

OBJECTIVE: The utility of CT findings in predicting long-term mortality in patients with acute pulmonary embolism (PE) is unknown. The purpose of this study is to retrospectively determine whether three CT findings--increased embolic burden, interventricular septal bowing toward the left ventricle, and right ventricle-to-left ventricle (RV/LV) diameter ratio greater than 1--are independent predictors of long-term all-cause mortality after acute PE. MATERIALS AND METHODS: A total of 1105 patients (47% female; mean age, 63 ± 16 years) with CT scans positive for PE from January 1, 1997, to December 31, 2002, were included. Scans were independently interpreted by two observers, with a third independent observer reviewing discrepant cases. CT findings and clinical information were compared with all-cause mortality using univariate and multivariate logistic regression analyses. RESULTS: The median duration of survival was 6.2 years following acute PE, with estimated 10-year survival of 37.4%. CT-derived embolic burden was associated with a very small decrease in long-term all-cause mortality in both univariate (hazard ratio [HR], 0.97; p < 0.001) and multivariate (HR, 0.97; p < 0.001) analyses. Interventricular septal bowing and RV/LV diameter ratio were not significantly associated with long-term all-cause mortality. CONCLUSION: CT findings are not predictive of decreased long-term survival after acute PE.

Effects of carbonate species on the kinetics of dechlorination of 1,1,1-trichloroethane by zero-valent iron.

The effect of precipitates on the reactivity of iron metal (Fe0) with 1,1,1-trichloroethane (TCA) was studied in batch systems designed to model groundwaters that contain dissolved carbonate species (i.e., C(IV)). At representative concentrations for high-C(IV) groundwaters (approximately 10(-2) M), the pH in batch reactors containing Fe0 was effectively buffered until most of the aqueous C(IV) precipitated. The precipitate was mainly FeCO3 (siderite) but may also have included some carbonate green rust. Exposure of the Fe0 to dissolved C(IV) accelerated reduction of TCA, and the products formed under these conditions consisted mainly of ethane and ethene, with minor amounts of several butenes. The kinetics of TCA reduction were first-order when C(IV)-enhanced corrosion predominated but showed mixed-order kinetics (zero- and first-order) in experiments performed with passivated Fe0 (i.e., before the onset of pitting corrosion and after repassivation by precipitation of FeCO3). All these data were described by fitting a Michaelis-Menten-type kinetic model and approximating the first-order rate constant as the ratio of the maximum reaction rate (Vm) and the concentration of TCA at half of the maximum rate (K(1/2)). The decrease in Vm/K(1/2) with increasing C(IV) exposure time was fit to a heuristic model assuming proportionality between changes in TCA reduction rate and changes in surface coverage with FeCO3.

Treating drug-dependent patients in hospitals.

Are hospital staff legally permitted to test drug-dependent patients for drugs or infectious disease without the patient's consent in order to treat the patient or to protect themselves or other patients? What should staff do with "suspicious" items in the patient's possession (drugs, credit cards in different names, firearms)? Can drug-dependent patients lawfully use illicit drugs in hospital? Who should supply and administer them?

A new seed-train expansion method for recombinant mammalian cell lines.

A new approach has been developed and used to minimize the timeand more carefully monitor and control the seed-train expansionprocess of recombinant mammalian cell lines. The process uses 50or 100 ml cryo-bags that contain frozen cells at high cell densities of 20 x 10(6) ml(-1) (100 ml bags) or 40 x 10(6) cells ml(-1) (50 ml bags). The frozen bag cell suspension is thawed and transferred directly into a bioreactorthat has been modified such that pH, DO and temperature can becontrolled at the initial volume of two liters (the working volume eventually increases to 12 l). The successful use of thesecryo-bags and the modified ;inoculation' bioreactor to initiate anew seed train expansion of rBHK or rCHO cells is described herein. The interval between cell thawing and the accumulation ofsufficient cell mass to inoculate a production reactor is reducedby at least 25 to 30 days compared to the conventional method that begins with the thaw of 1-2 ml cryo-vials. This ;one-step'technology leads to a much more consistent scale-up by reducingmanual operations and avoiding subjective decisions during the scale-up phase. The cell metabolic rates and product integritywere similar to the control experiments. Furthermore, it was found that it is not necessary to include a wash step to removeDMSO prior to the inoculation.