Calcium oxalate crystal formation in the kidneys of rats injected with 4-hydroxy-L-proline

Summary Calcium oxalate crystal formation induced in rat kidneys by intraperitoneal injection of 4-hydroxy-L-proline were studied by chemical, microscopic and size analysis techniques. Crystal growth rates were determined at different intervals of time from the size distribution curves. Calcium oxalate dihydrate (weddelite), formed in the first 2 hour after injection, undergoes gradual phase transformation to the more stable monohydrate (whewellite). This finding emphasizes the significance of crystal transformation in the development of experimental nephrolithiasis.     

Deletion of the distal COOH-terminus of the A2B adenosine receptor switches internalization to an arrestin- and clathrin-independent pathway and inhibits recycling

Background and purpose:

We have investigated the effect of deletions of a postsynaptic density, disc large and zo-1 protein (PDZ) motif at the end of the COOH-terminus of the rat A_2B adenosine receptor on intracellular trafficking following long-term exposure to the agonist 5′-(N-ethylcarboxamido)-adenosine.

Experimental approach:

The trafficking of the wild type A_2B adenosine receptor and deletion mutants expressed in Chinese hamster ovary cells was studied using an enzyme-linked immunosorbent assay in combination with immunofluorescence microscopy.

Key results:

The wild type A_2B adenosine receptor and deletion mutants were all extensively internalized following prolonged treatment with NECA. The intracellular compartment through which the Gln³²⁵-stop receptor mutant, which lacks the Type II PDZ motif found in the wild type receptor initially trafficked was not the same as the wild type receptor. Expression of dominant negative mutants of arrestin-2, dynamin or Eps-15 inhibited internalization of wild type and Leu³³⁰-stop receptors, whereas only dominant negative mutant dynamin inhibited agonist-induced internalization of Gln³²⁵-stop, Ser³²⁶-stop and Phe³²⁸-stop receptors. Following internalization, the wild type A_2B adenosine receptor recycled rapidly to the cell surface, whereas the Gln³²⁵-stop receptor did not recycle.

Conclusions and implications:

Deletion of the COOH-terminus of the A_2B adenosine receptor beyond Leu³³⁰ switches internalization from an arrestin- and clathrin-dependent pathway to one that is dynamin dependent but arrestin and clathrin independent. The presence of a Type II PDZ motif appears to be essential for arrestin- and clathrin-dependent internalization, as well as recycling of the A_2B adenosine receptor following prolonged agonist addition.     

Ceramic-on-ceramic vs ceramic-on-polyethylene,a comparative study with 10-year follow-up

BACKGROUNDIn press-fit total hip arthroplasty (THA) ceramic-on-ceramic (CoC) bearings are a potential for overcoming the wear that is seen in ceramic-on-polyethylene (CoPE) bearings, and can lead to wear-induced osteolysis, resulting in loosening of the implant. However, CoC bearings show disadvantages as well, such as squeaking sounds and being more fragile, which can cause ceramic head or liner fracture. Because comparative long-term studies are limited, the objective of this study was to determine the long-term difference in wear, identify potential predictive factors for wear, investigate radiological findings such as osteolysis, and evaluate clinical functioning and complications between these bearings.AIMTo determine 10-year differences in wear, predictive factors for wear, and investigate radiological findings and clinical functioning between CoC and CoPE.METHODSThis observational prospective single-center cohort study with a 10-year follow-up includes a documented series of elective THAs. Primary outcome was wear measured by anteroposterior (AP) radiographs. Secondary outcomes were potential predictive factors for wear, complications during follow-up, Harris hip score (HHS), and radiological findings such as presence of radiolucency, osteolysis, atrophy, and hypertrophy around the cup. Due to the absence of wear in the CoC group, stratified analysis to identify risk factors for wear was only performed in the CoPE group by use of univariate linear regression analysis. HHS was expressed as a change from baseline and the association with bearing type was assessed by use of multivariate linear regression analysis, adjusted for potential confounders.RESULTSA total of 17 CoPE (63.0%) and 25 CoC (73.5%) cases were available for follow-up and showed a linear wear of respectively 0.130 mm/year (range 0.010; 0.350) and 0.000 mm/year (range 0.000; 0.005), which was significant (P < 0.001) between both groups. Wear always occurred in the cranial direction. Cup inclination was the only predictive factor for polyethylene (PE) wear. No dislocations, ceramic head, or liner fractures were seen. The HHS showed a mean change from baseline of 37.1 points (SD 18.5) in the CoPE group and 43.9 (SD 17.0) in the CoC group. This crude difference of 6.8 (range -5.2; 18.7) in favor of the CoC group was not significant (P = 0.26) and was not significant when adjusted for age, gender, and diagnosis either (P = 0.99). No significant differences in complications and radiological findings were seen between groups. CONCLUSIONCoC bearing shows lower wear rates compared to CoPE at 10-year follow-up with cup inclination as a predictive factor for wear and no differences in complications, HHS, and radiological findings.     

Privatizing indigent health services in Los Angeles County: understanding the effects on community-based providers.

Faced with imminent financial collapse of its public healthcare system, the Los Angeles County Department of Health Services solicited community-based providers to supply primary care health services to the medically indigent. This study highlights the effects that participation in the programme has had on these community providers. While strongly committed to the programme's objectives, community providers tended to overextend themselves financially, putting their organizations at substantial risk of failure should contractual expectations or patient demand forecasts not be met. Because of this risk, policymakers involved in public-private partnerships with community-based providers must exercise extreme caution owing to the unique status many of these providers hold as centrally positioned actors in their communities. On the positive side, we found evidence of increased levels of co-operation and innovation between community providers outside their formal roles in the county-sponsored public-private partnership programme.     

How Much Labor Is in a Labor Epidural?: Manpower Cost and Reimbursement for an Obstetric Analgesia Service in a Teaching Institution

Background: Some anesthesiologists avoid provision of obstetric analgesia services (OAS) because of low reimbursement rates for the work involved. This study defines the manpower costs of operating an OAS in a tertiary referral center and examines reimbursement for this cost.

Methods: The time spent providing OAS in a total of 55 parturients was studied prospectively using a modification of classic time and motion studies.

Results: Mean duration of OAS in our population was 412 +/- 313 min. Mean bedside anesthesia staff time was 90 +/- 40 min, and mean number of visits to each patient's bedside was 6.3 +/- 2.0 visits. Assuming staffing on demand for service (intermittent staffing), a minimum of 2.5 full-time equivalent (FTE) attending anesthesiologists was required to meet demand. With intermittent staffing, labor cost was $325 per patient. Actual practice at Duke University Medical Center is around-the-clock (dedicated) staffing, which requires 4.4 FTEs at a cost of $728 per patient. Neither average indemnity reimbursement ($299) nor Medicaid reimbursement ($204) covered the cost per OAS patient. Breaking even is possible under indemnity reimbursement because operating room reimbursement subsidizes OAS costs. Breaking even cannot occur with Medicaid reimbursement under any circumstances.     

A pilot study of an online workplace nutrition program: the value of participant input in program development

ObjectiveTailored nutrition Web programs constitute an emerging trend in obesity prevention. Initial investment in innovative technology necessitates that the target population be well understood. This pilot study's purpose was to determine the feasibility of a workplace nutrition Web program.DesignFormative research was conducted with gaming industry employees and benefits managers to develop a consensus on workplace-specific nutrition needs. A demonstration Web program was piloted with stakeholders to determine feasibility.SettingIndiana, Mississippi, Nevada, and New Jersey gaming establishments.Participants86 employees, 18 benefits managers.InterventionPrototype Web program.Main Outcome MeasuresConcept mapping; 16-item nutrition knowledge test; satisfaction.AnalysisConcept mapping was used to aggregate importance ratings on programmatic content, which informed Web program curriculum. Chi-square tests were performed postintervention to determine knowledge improvement.Results(1) Employees and benefits managers exhibited moderate agreement about content priorities for the program (r = 0.48). (2) There was a significant increase in employees' nutrition knowledge scores postintervention (t = 7.16, df = 36, P < .001); those with less knowledge exhibited the greatest gains in knowledge scores (r = −0.647, P < .001).Conclusions and ImplicationsEmployees and benefit managers do not necessarily agree on the priority of nutrition-related content, suggesting a need for programs to appeal to various stakeholders. Computer-based approaches can address various stakeholder health concerns via tailored, customized programming.     

镉相关翻译启动因子TIF3致Ras癌基因蛋白的异常表达

目的 研究镉相关翻译启动因子TIF3对多种细胞肿瘤相关基因表达的影响,探索镉的分子致癌机制。方法应用TIF3基因真核细胞稳定表达系统和Western blot检测技术,用各种单克隆抗体检测细胞肿瘤相关基因蛋白的表达情况。结果 相对于载体转染中国仓鼠卵巢(CHO)对照细胞,在4株具有高效稳定表达TIF3编码蛋白质的CHO细胞系中均有pan—ras癌基因蛋白异常表达,其编码蛋白(21kDa)含量均明显高于对照组;其余肿瘤相关基因蛋白如c—myc．c-jun,MDM2,ODC,P16,p53,Cyclin D1的表达蛋白在TIF3转基因细胞与对照细胞之间未见明显差别。结论 镉相关翻译启动因子TIF3是一种镉应答原癌基因,TIF3的超额表达可导致Ras癌基因蛋白异常表达,这可能是镉应答原癌基因TIF3的分子致癌机制。     

WONCA Online电子病例介绍颈内动脉-海绵窦瘘、硬脑膜动静脉畸形

患者，男，68岁，因右眼红肿4d到急诊科就诊。