Repeat Low‐Trauma Fractures Occur Frequently Among Men and Women Who Have Osteopenic BMD

Fracture risk assessment based solely on BMD has limitations. Additional risk factors include the presence of a previous low‐trauma fracture. We sought to quantify the fracture burden attributable to first versus repeat fracture. We studied 2179 men and 5269 women, 50–90 yr of age, participating in the Canadian Multicentre Osteoporosis Study (CaMos). We included all low‐trauma fractures that occurred over 8 yr of follow‐up and classified these as either first or repeat clinical low‐trauma fracture based on lifetime fracture history. Analyses were further stratified by sex, age, BMD risk categories (normal, osteopenia, osteoporosis), and vertebral deformity status. There were 128 fractures in men and 577 fractures in women. About 25% of fractures in men and 40% in women were repeat fractures. Just over one half of first fractures occurred in those with osteopenic BMD (58% in men, 54% in women). Just under one half of repeat fractures also occurred in those with osteopenic BMD (42% in men, 47% in women). The incidence of repeat fracture was, in most cases, nearly double, but sometimes nearly quadruple, the incidence of first fracture within a given BMD risk category in both men and women. Repeat fractures contribute substantially to overall fracture burden, and the contribution is independent of BMD. Furthermore, those with a combination of prior low‐trauma fracture and another risk factor were at especially high risk of future fracture.     

Poor Intraoperative Blood Glucose Control Is Associated with a Worsened Hospital Outcome after Cardiac Surgery in Diabetic Patients

Background: Tight perioperative control of blood glucose improves the outcome of diabetic patients undergoing cardiac surgery. Because stress response and cardiopulmonary bypass can induce profound hyperglycemia, intraoperative glycemic control may become difficult. The authors undertook a prospective cohort study to determine whether poor intraoperative glycemic control is associated with increased intrahospital morbidity.

Methods: Two hundred consecutive diabetic patients undergoing on-pump heart surgery were enrolled. A standard insulin protocol based on subcutaneous intermediary insulin was given the morning of the surgery. Intravenous insulin therapy was initiated intraoperatively from blood glucose concentrations of 180 mg/dl or greater and titrated according to a predefined protocol. Poor intraoperative glycemic control was defined as four consecutive blood glucose concentrations greater than 200 mg/dl without any decrease in despite insulin therapy. Postoperative blood glucose concentrations were maintained below 140 mg/dl by using aggressive insulin therapy. The main endpoints were severe cardiovascular, respiratory, infectious, neurologic, and renal in-hospital morbidity.

Results: Insulin therapy was required intraoperatively in 36% of patients, and poor intraoperative glycemic control was observed in 18% of patients. Poor intraoperative glycemic control was significantly more frequent in patients with severe postoperative morbidity (37% vs. 10%; P < 0.001). The adjusted odds ratio for severe postoperative morbidity among patients with a poor intraoperative glycemic control as compared with patients without was 7.2 (95% confidence interval, 2.7-19.0).     

Increased apical targeting of renal epithelial sodium channel subunits and decreased expression of type 2 11beta-hydroxysteroid dehydrogenase in rats with CCl4-induced decompensated liver cirrhosis

It was hypothesized that dysregulation of renal epithelial sodium channel (ENaC) subunits and/or 11beta-hydroxysteroid dehydrogenase (11betaHSD2) may play a role in the increased sodium retention in liver cirrhosis (LC). Experimental LC was induced in rats by CCl(4) (1 ml/kg, intraperitoneally, twice a week) for 12 wk (protocol 1) or for 11 wk (protocol 2). In both protocols, one group of rats with cirrhosis showed significantly decreased urinary sodium excretion and urinary Na/K ratio (group A), whereas a second group exhibited normal urinary sodium excretion (group B) compared with controls, even though extensive ascites was seen in both groups of rats with cirrhosis. In group A, protein abundance of alpha-ENaC was unchanged, whereas beta-ENaC abundance was decreased in the cortex/outer stripe of outer medulla compared with controls. The gamma-ENaC underwent a complex change associated with increased abundance of the 70-kD band with a concomitant decrease in the main 85-kD band, corresponding to an aldosterone effect. In contrast, no changes in the abundance of ENaC subunit were observed in group B. Immunoperoxidase microscopy revealed an increased apical targeting of alpha-, beta-, and gamma-ENaC subunits in distal convoluted tubule (DCT2), connecting tubule (CNT), and cortical and medullary collecting duct segments in group A but not in group B. Immunolabeling intensity of 11betaHSD2 in the DCT2, CNT, and cortical collecting duct was significantly reduced in group A but not in group B, and this was confirmed by immunoblotting. In conclusion, increased apical targeting of ENaC subunits combined with diminished abundance of 11betaHSD2 in the DCT2, CNT, and cortical collecting duct is likely to play a role in the sodium retaining stage of liver cirrhosis.     

Poor intraoperative blood glucose control is associated with a worsened hospital outcome after cardiac surgery in diabetic patients

BACKGROUND: Tight perioperative control of blood glucose improves the outcome of diabetic patients undergoing cardiac surgery. Because stress response and cardiopulmonary bypass can induce profound hyperglycemia, intraoperative glycemic control may become difficult. The authors undertook a prospective cohort study to determine whether poor intraoperative glycemic control is associated with increased intrahospital morbidity. METHODS: Two hundred consecutive diabetic patients undergoing on-pump heart surgery were enrolled. A standard insulin protocol based on subcutaneous intermediary insulin was given the morning of the surgery. Intravenous insulin therapy was initiated intraoperatively from blood glucose concentrations of 180 mg/dl or greater and titrated according to a predefined protocol. Poor intraoperative glycemic control was defined as four consecutive blood glucose concentrations greater than 200 mg/dl without any decrease in despite insulin therapy. Postoperative blood glucose concentrations were maintained below 140 mg/dl by using aggressive insulin therapy. The main endpoints were severe cardiovascular, respiratory, infectious, neurologic, and renal in-hospital morbidity. RESULTS: Insulin therapy was required intraoperatively in 36% of patients, and poor intraoperative glycemic control was observed in 18% of patients. Poor intraoperative glycemic control was significantly more frequent in patients with severe postoperative morbidity (37% vs. 10%; P < 0.001). The adjusted odds ratio for severe postoperative morbidity among patients with a poor intraoperative glycemic control as compared with patients without was 7.2 (95% confidence interval, 2.7-19.0). CONCLUSION: Poor intraoperative control of blood glucose concentrations in diabetic patients undergoing cardiac surgery is associated with a worsened hospital outcome after surgery.     

Autoimmune responses against renal tissue proteins in long-term surviving allograft recipients

Major histocompatibility complex antigens (MHC) are classical targets of recipient responses to allotransplants. However, the role of an immune response directed against autologous graft tissue determinants is poorly defined. In this study, we investigated (i) whether autologous kidney tissue extract can induce an immune response to autologous kidney proteins in normal rats, and (ii) if a similar autologous response develops in the long-term surviving LEW.1A recipients of an MHC-mismatched LEW.1W kidney (RT1^u to RT1^a). LEW.1A rats immunized with allo- or syngeneic soluble kidney extracts developed a T-cell response to self antigens as shown by the frequency of specific IFN-γ-producing T cells from LEW.1A rats in the presence of extracts (ELISPOT). In contrast, they responded only marginally to dominant RT1^u determinants. The ELISPOT against fractions of soluble autologous kidney extracts separated by an FPLC gel-filtration system indicated a preferential response to megalin, a high molecular weight protein that has been shown to be involved in experimental Heymann nephritis. In a model of long-term kidney allograft survival by anti-CD28 administration, recipients also developed humoral but not cellular responses to megalin. Our data suggest that autoimmune processes develop in long-term surviving kidney allograft recipients.     

Designing a workplace return-to-work program for occupational low back pain: an intervention mapping approach

Background  

Despite over 2 decades of research, the ability to prevent work-related low back pain (LBP) and disability remains elusive. Recent research suggests that interventions that are focused at the workplace and incorporate the principals of participatory ergonomics and return-to-work (RTW) coordination can improve RTW and reduce disability following a work-related back injury. Workplace interventions or programs to improve RTW are difficult to design and implement given the various individuals and environments involved, each with their own unique circumstances. Intervention mapping provides a framework for designing and implementing complex interventions or programs. The objective of this study is to design a best evidence RTW program for occupational LBP tailored to the Ontario setting using an intervention mapping approach.     

Dynamic MR imaging of osteoid osteomas: correlation of semiquantitative and quantitative perfusion parameters with patient symptoms and treatment outcome

Objective

To evaluate the relationship between multiple MR perfusion parameters and symptoms of patients with osteoid osteomas after percutaneous laser therapy.

Methods

MR perfusion studies of 20 patients diagnosed with an osteoid osteoma, treated with CT-guided percutaneous laser therapy, were retrospectively evaluated. Multiple perfusion parameters correlated with the treatment outcome and the presence of osteoid osteoma-related symptoms.

Results

There were 16 successful treatments, 6 recurrences and a significant difference in the perfusion parameters of these groups (P?<?0.0001). Patients with successful treatment demonstrated delayed progressive enhancement or no enhancement (mean time to peak?=?182 s, mean delay to the arterial peak?=?119.3 s). Patients with treatment failure demonstrated an early and steep enhancement (mean time to peak?=?78 s and mean delay to the arterial peak?=?24 s). Plasmatic volume and transfer constant values significantly changed after successful treatment (P?<?0.008). MR perfusion has a sensitivity and a specificity higher than 90 % in the detection of recurrent osteoid osteomas.

Conclusion

The identification of an early and steep enhancement with short time to peak and a short delay between the arterial and nidus peaks on MR perfusion in the postoperative setting is highly indicative of an osteoid osteoma recurrence. Key points ? Magnetic resonance perfusion is becoming widely used for several tumours. ? MR perfusion measurements correlate well with osteoid osteoma-related symptoms. ? MR perfusion has high diagnostic performance for osteoid osteoma recurrence. ? MR perfusion can improve the diagnostic confidence of osteoid osteoma recurrence.     

The effect of raloxifene treatment in postmenopausal women with CKD

It is unknown whether treatment for osteoporosis with raloxifene is safe or effective in those with chronic kidney disease (CKD). With data from a multicenter, randomized, placebo-controlled trial of 7705 postmenopausal women with osteoporosis, the effect of raloxifene on rate of change of bone mineral density (BMD), incidence of fractures, and adverse events by stage of CKD was examined over 3 yr. Baseline serum creatinine values were available for 7316 women, and these values were used to assign a category of creatinine clearance (CrCl) using the Cockcroft-Gault formula (CrCl < 45, 45 to 59, and > or = 60 ml/min). BMD was measured at baseline and annually by dual x-ray absorptiometry. Within the placebo group, lower baseline CrCl was associated with a trend for higher annual losses of BMD at the femoral neck; however, within the raloxifene group, lower baseline CrCl was associated with greater increases in femoral neck BMD. This interaction between category of CrCl and treatment assignment was significant for rate of change of BMD at the hip. Irrespective of kidney function, raloxifene treatment was associated with a greater increase in spine BMD, a reduction in vertebral fractures, and no effect on nonvertebral fractures compared with placebo. Within each category of kidney function, adverse events were similar between the raloxifene and placebo groups. In conclusion, raloxifene increases BMD at both the hip and the spine and reduces the risk for vertebral fractures among individuals with CKD. The effect ofraloxifene on hip BMD is greater among those with mild to moderate CKD.     

Calcium-sensing receptor attenuates AVP-induced aquaporin-2 expression via a calmodulin-dependent mechanism

Recent evidence suggests that arginine vasopressin (AVP)-dependent aquaporin-2 expression is modulated by the extracellular calcium-sensing receptor (CaSR) in principal cells of the collecting duct, but the signaling pathways mediating this effect are unknown. Using a mouse cortical collecting duct cell line (mpkCCD(cl4)), we found that increasing the concentration of apical extracellular calcium or treating with the CaSR agonists neomycin or Gd(3+) attenuated AVP-dependent accumulation of aquaporin-2 mRNA and protein; CaSR gene-silencing prevented this effect. Calcium reduced the AVP-induced accumulation of cAMP, but this did not occur by increased degradation of cAMP by phosphodiesterases or by direct inhibition of adenylate cyclase. Notably, the effect of extracellular calcium on AVP-dependent aquaporin-2 expression was prevented by inhibition of calmodulin. In summary, our results show that high concentrations of extracellular calcium attenuate AVP-induced aquaporin-2 expression by activating the CaSR and reducing coupling efficiency between V(2) receptor and adenylate cyclase via a calmodulin-dependent mechanism in cultured cortical collecting duct cells.