Passive angle measurement based localization consistency via geometric constraints

In this paper, we examine the geometric relations between various measured parameters and their corresponding errors in angle-measurement based emitter localization scenarios. We derive a geometric constraint formulating the relationship among the measurement errors in such a scenario. Using this constraint, we formulate the localization task as a constrained optimization problem that can be performed on the measurements in order to provide the optimal values such that the solution is consistent with the underlying geometry.

Modelling the fate of chromated copper arsenate in a sandy soil

A pulse of chromated copper arsenate (CCA, a timber preservative) was applied in irrigation water to an undisturbed field soil in a laboratory column. Concentrations of various elements in the leachate from the column were measured during the experiment. Also, the remnants within the soil were measured at the end of the experiment. The geochemical modelling package, PHREEQC-2, was used to simulate the experimental data. Processes included in the CCA transport modelling were advection, dispersion, non-specific adsorption (cation exchange) and specific adsorption by clay minerals and organic matter, as well as other possible chemical reactions such as precipitation/dissolution. The modelling effort highlighted the possible complexities in CCA transport and reaction experiments. For example, the uneven dosing of CCA as well as incomplete knowledge of the soil properties resulted in simulations that gave only partial, although reasonable, agreement with the experimental data. Both the experimental data and simulations show that As and Cu are strongly adsorbed and therefore, will mostly remain at the top of the soil profile, with a small proportion appearing in leachate. On the other hand, Cr is more mobile and thus it is present in the soil column leachate. Further simulations show that both the quantity of CCA added to the soil and the pH of the irrigation water will influence CCA transport. Simulations suggest that application of larger doses of CCA to the soil will result in higher leachate concentrations, especially for Cu and As. Irrigation water with a lower pH will dramatically increase leaching of Cu. These results indicate that acidic rainfall or significant accidental spillage of CCA will increase the risk of groundwater pollution.

Psychometric properties of the modified Emory functional ambulation profile in stroke patients

Objective: To examine the test – retest reliability, convergent and predictive validity and responsiveness of the modified Emory Functional Ambulation Profile (mEFAP) in assessing gait function in stroke patients undergoing rehabilitation. Subjects: Forty subacute stroke inpatients were enrolled in the validity and responsiveness study. Twenty chronic patients participated in the reliability study. Setting: Rehabilitation department of a medical centre. Design: In the validity and responsiveness study, patients were tested using the mEFAP, 10-m walking speed test, Barthel Index and Rivermead Mobility Index at admission and at discharge. For the reliability study, the patients completed the mEFAP twice one week apart. Results: The patients' performances on the mEFAP were moderately to highly correlated with results of the 10-m walking speed test and Rivermead Mobility Index (absolute correlation coefficients ≥ 0.67), indicating good convergent validity. Patients' performance on the mEFAP at admission was moderately correlated with the Barthel Index and Rivermead Mobility Index scores at discharge (Spearman's rank correlation coefficients = -0.52 and -0.78, respectively), indicating good predictive validity. The standardized response mean of the mEFAP was 1.1 (P < 0.0001), suggesting good responsiveness. The intraclass correlation coefficient ICC(3,1) for the mEFAP was 0.997, indicating excellent test – retest reliability. Conclusions: Our results provide strong evidence that the mEFAP has good reliability, validity and responsiveness for assessing stroke patients undergoing rehabilitation. The mEFAP is a useful scale for measuring walking function and recovery in stroke patients.

Effect of Glucocorticoid pretreatment on oxidative liver injury and survival in jaundiced rats with Endotoxing Cholangitis

Introduction: Biliary tract infection is associated with high mortality. This study investigated the effect of glucocorticoid pretreatment on lipopolysaccharide (LPS)-induced cholangitis. Methods: Rats undergoing either sham operation or ligation of the extrahepatic bile duct (BDL) for 2 weeks were randomly assigned to receive intravenous injections of dexamethasone (DX) or normal saline (NS) prior to infusing LPS into the biliary tract. The plasma levels of tumor necrosis factor-α (TNFα), chemokines monocyte chemoattractant protein-1 (MCP-1) and macrophage inflammatory protein-2 (MIP-2) as well as liver mRNA expression of MCP-1 and MIP-2 were determined. Infiltration of monocytes, Kupffer cells, and neutrophils in rat liver were studied with immunohistochemistry. Oxidative liver injury was measured by the malondialdehyde (MDA) content. Results: Dexamethasone pretreatment resulted in significantly decreased plasma levels of TNFα at 1 hour, MCP-1 and MIP-2 at 2 and 3 hours, and decreased liver MCP-1 mRNA expression at 3 hours following LPS infusion in BDL-DX rats than in BDL-NS rats. The number of inflammatory cells in the liver was significantly different between sham- and BDL-treated rats but was not affected by DX pretreatment. Pretreatment with DX resulted in significantly decreased liver MDA contents in the BDL-DX group than that in the BDL-NS group. Jaundiced rats pretreated with 5 mg DX prior to infusion of 1 g of LPS were 6.8 times more likely to survive than those that were not pretreated. Conclusions: Pretreatment of jaundiced, LPS-treated rats with a  supraphysiological dose of dexamethasone may rescue their lives by suppression of chemokine expression and alleviation of oxidative liver injury.

Analysis of cardioprotective effects using purified Saliva miltiorrhiza extract on isolated rat hearts

The purpose of the current study is to evaluate the cardioprotective effects of purified Salvia miltiorrhiza extract (PSME) on myocardial ischemia/reperfusion injury in isolated rat hearts. Hearts were excised and perfused at constant flow (7 – 9 ml · min⁻¹) via the aorta. Non-recirculating perfusion with Krebs-Henseleit (KH) solution was maintained at 37°C and continuously gassed with 95% O₂ and 5% CO₂. KH solution with or without PSME (100 mg per liter solution) was used after 30-min zero-flow ischemia for the PSME and control group, respectively. Left ventricular (LV) developed pressure; its derivatives, diastolic pressure, and so on were continuously recorded via a pressure transducer attached to a polyvinylchloride balloon that was placed in the left ventricle through an incision in the left atrium. PSME treated hearts showed significant postischemic contractile function recovery (developed pressure recovered to 44.2 ± 4.9% versus 17.1 ± 5.7%, P<0.05; maximum contraction recovered to 57.2 ± 5.9% versus 15.1 ± 6.3%, P<0.001; maximum relaxation restored to 69.3 ± 7.3% versus 15.4 ± 6.3%, P<0.001 in the PSME and control group, respectively). Significant elevation in end-diastolic pressure, which indicated LV stiffening in PSME hearts might have resulted from the excess high dose of PSME used. Further study will be conducted on the potential therapeutic value with lower dose of PSME on prevention of ischemic heart disease.

Predicting the grade of disability 1 year after stroke following rehabilitation

The purpose of this study was to identify predictors of grades of disability at least 1 year after stroke rehabilitation therapy. We recruited stroke patients from the inpatient rehabilitation department of a university hospital. The degree of disability was graded using the disability evaluation at least 1 year after stroke onset. Functional ability was evaluated using the Functional Independence Measure instrument on admission, on discharge from the inpatient rehabilitation program, and at the 6-month follow-up visit after discharge. Major sociodemographic, medical, and rehabilitative factors were also collected during the hospitalization period. Of the 109 patients surveyed, 64 (58.7%) had severe or very severe grades of disability. The correlates of severe or very severe disability in logistic regression analyses were bilaterally affected (odds ratio, OR, 10.8), impaired orientation (OR, 3.6), and poorer functional ability at discharge (OR, 7.6). Based on the significant predictors identified, the logistic regression model correctly classified severe or very severe disability in 68.0% of subjects. The higher frequency of severe or very severe disability in this study may have been due to the relatively more severely affected stroke patient population in the inpatient rehabilitation service and the use of unique disability evaluation criteria. These results may provide information useful in planning continuous rehabilitation care and setting relevant socio-welfare policies for stroke victims.

Acetylcysteine for prevention of acute deterioration of renal function following elective coronary angiography and intervention

Context The antioxidant acetylcysteine prevents acute contrast nephrotoxicity in patients with impaired renal function who undergo computed tomography scanning. However, its role in coronary angiography is unclear.

Objective To determine whether oral acetylcysteine prevents acute deterioration in renal function in patients with moderate renal insufficiency who undergo elective coronary angiography.

Design and Setting Prospective, randomized, double-blind, placebo-controlled trial conducted from May 2000 to December 2001 at the Grantham Hospital at the University of Hong Kong.

Participants Two hundred Chinese patients aged mean (SD) 68 (6.5) years with stable moderate renal insufficiency (creatinine clearance <60 mL/min [1.00 mL/s]) who were undergoing elective coronary angiography with or without intervention.

Intervention Participants were randomly assigned to receive oral acetylcysteine(600 mg twice per day; n = 102) or matching placebo tablets (n = 98) on the day before and the day of angiography. All patients received low-osmolality contrast agent.

Main Outcome Measures Occurrence of more than a 25% increase in serum creatinine level within 48 hours after contrast administration; change in creatinine clearance and serum creatinine level.

Results Twelve control patients (12%) and 4 acetylcysteine patients (4%) developed a more than 25% increase in serum creatinine level within 48 hours after contrast administration (relative risk, 0.32; 95% confidence interval [CI], 0.10-0.96; P = .03). Serum creatinine was lower in the acetylcysteine group (1.22 mg/dL [107.8 µmol/L]; 95% CI, 1.11-1.33 mg/dL vs 1.38 mg/dL [122.9 µmol/L]; 95% CI, 1.27-1.49 mg/dL; P = .006) during the first 48 hours after angiography. Acetylcysteine treatment significantly increased creatinine clearance from 44.8 mL/min (0.75 mL/s) (95% CI, 42.7-47.6 mL/min) to 58.9 mL/min (0.98 mL/s) (95% CI, 55.6-62.3 mL/min) 2 days after the contrast administration (P<.001).The increase was not significant in the control group (from 42.1 to 44.1 mL/min [0.70 to 0.74 mL/s]; P = .15). The benefit of acetylcysteine was consistent among various patient subgroups and persistent for at least 7 days. There were no major treatment-related adverse events.

Conclusion Acetylcysteine protects patients with moderate chronic renal insufficiency from contrast-induced deterioration in renal function after coronary angiographic procedures, with minimal adverse effects and at a low cost.

Renal transplantation in patients with primary immunoglobulin A nephropathy

Background. Opinions on the clinical course and outcome of renal transplantation in patients with primary immunoglobulin A nephropathy (IgAN) have been controversial.
Methods. We conducted a retrospective single-centre study on 542 kidney transplant recipients over the period 1984–2001. Long-term outcome and factors affecting recurrence in recipients with primary IgAN were analysed.
Results. Seventy-five patients (13.8%) had biopsy-proven IgAN as the cause of renal failure, and their mean duration of follow-up after transplantation was 100 ± 5.8 months. Fourteen (18.7%) of the 75 patients had biopsy-proven recurrent IgAN, diagnosed at 67.7 ± 11 months after transplantation. The risk of recurrence was not associated with HLA DR4 or B35. Graft failure occurred in five (35.7%) of the 14 patients: three due to IgAN and two due to chronic rejection. Three (4.9%) of the 61 patients without recurrent IgAN had graft failure, all due to chronic rejection. Graft survival was similar between living-related and cadaveric/living-unrelated patients (12-year graft survival, 88 and 72%, respectively, P = 0.616). Renal allograft survival within the first 12 years was better in patients with primary IgAN compared with those with other primary diseases (80 vs 51%, P = 0.001). Thereafter, IgAN patients showed an inferior graft survival (74 vs 97% in non-IgAN patients, P = 0.001).
Conclusions. Our data suggested that around one-fifth of patients with primary IgAN developed recurrence by 5 years after transplantation. Recurrent IgA nephropathy in allografts runs an indolent course with favourable outcome in the first 12 years. However, the contribution of recurrent disease to graft loss becomes more significant on long-term follow up.

Prediction of functional oucomes in stroke inpatients receiving rehabilitation

Background and Purpose: Early identification of predictive factors relevant to functional outcomes for stroke patients is important to the establishment of an effective continuing care program. The objective of this studywas to identify the predictive factors related to functional outcome at discharge after stroke rehabilitation therapy. Methods: 105 first-time stroke patients admitted to the inpatient rehabilitation department of a university-based medical center were recruited for this prospective study. The functional outcomes of the patients were assessed at admission and at discharge using the Functional Independence Measure (FIM). Severity of stroke was determined using the Canadian Neurological Scale (CNS). Age, gender, side of hemiplegia (SIDE), type of stroke (TYPE), onset to admission interval (OAI), and length of rehabilitation stay (LORS) were also included as predictor variables. Results: The mean (′SD) FIM score at discharge (76.6 ′ 26.4) correlated strongly (r = 0.78, p < 0.001) with the admission FIM score (56.3 ′ 24.1), moderately (r = 0.46, p < 0.001) with the admission CNS score (6.1 ′ 2.2), negatively (r = -0.38, p < 0.001) with age (63.2 ′ 12.3 years), negatively (r = -0.26, p = 0.009) with OAI (24.2 ′ 16.0 days), and negatively (r = -0.29, p = 0.002) with LORS (34.7 ′ 16.8 ays). Stepwise regression analyses indicated that admission FIM score, age, and admission CNS score were the stronge predictors of functional outcome and accounted for 66% of the total variation in discharge FIM total score. The admission FIM score was the best predictor and accounted for 61% of the variation. Conclusions: The findings of this study imply that the admission FIM scores for inpatients receiving stroke rehabilitation can be used to predict functional outcomes at discharge from hospital.