Bone density ligand, Sclerostin, directly interacts with LRP5 but not LRP5G171V to modulate Wnt activity.

We compared and contrasted the mechanism of action for the cysteine knot protein subfamily, Wise and Sost (Sclerostin). Our data suggest that functional interactions between Sost or Wise and LRP5/LRP6 have the potential to regulate bone deposition by modulating the Wnt pathway. INTRODUCTION: The human disease sclerosteosis exhibits an increase in bone mass thought to be caused by hyperactive osteoblasts. Sclerostin, SOST, the gene affected in this disease, has been postulated to exert its activity by functioning as a BMP antagonist. However, recent evidence indicates that SOST is highly related to Wise, which can also modulate the Wnt pathway by binding to LRP5 and LRP6. MATERIALS AND METHODS: For this study, we used cell culture to test the BMP and Wnt activity function of both Wise and Sost. In addition, we used Xenopus in vivo Wnt assays along with Xenopus in vitro Wnt assays to support our cell culture results. Epitope tagged cell supernatants containing either Sost or soluble mutant or wildtype LRP5/LRP6 were used for immunoprecipitation. Sost immunoprecipitation results were confirmed in vivo using cell culture. Finally, to support our in vitro data, we co-localized Sost, Wise, LRP5, and LRP6 in mouse long bone sections. Results: In this study, we report in vitro and in vivo evidence to show that Sost physically interacts with Lrp5 and Lrp6 and inhibits the canonical Wnt signaling pathway. Furthermore, using in vitro and in vivo assays, we showed that a variant of LRP5 (LRP5(G171V)) known to cause the human high bone mass (HBM) trait and a homologous change in LRP6 (LRP6(G158V)) abolished protein interactions with Sost. We used variants of Sost amino acids to further identify the contact points between Sost and LRP6. In Xenopus and mammalian cell culture assays, we showed that SOST is able to attenuate Wnt signaling and that this attenuation can be rescued by the addition of alpha-Sost antibodies or by the introduction of single amino acid substitution that alter its binding to LRP6. Sost differs from Wise in that it is unable to stimulate Wnt signaling. Using immunohistochemistry, we found that Sost and Wise are co-localized to osteoblasts, along with LRP5 and LRP6. CONCLUSIONS: Our data suggest that functional interactions between Sost or Wise and LRPs have the potential to regulate bone deposition by modulating Wnt signaling.     

Bleeding complications associated with peritoneal dialysis catheter insertion.

OBJECTIVE: To identify the incidence of bleeding complications associated with peritoneal dialysis catheter insertion. DESIGN: Retrospective review at a tertiary-care center of all double-cuffed Tenckhoff catheters placed surgically from 1 January 1992 to 1 October 2003 to identify the incidence of major bleeding complications occurring with catheter insertion. Major bleeding episodes were defined as > or = 3% decline in hematocrit, or the need for surgical intervention or blood transfusion within 2 weeks of insertion. RESULTS: 292 catheters had been inserted in 263 patients. Six patients satisfied the criteria for a major bleeding event, for a major bleeding complication rate of 2%. Bleeding was associated with perioperative anticoagulation in 3 patients, uremia and thrombocytopenia in 1 patient, aspirin use and thrombocytopenia in 1 patient, and 1 patient experienced intraoperative bleeding. Coagulation parameters were not obtained prior to the procedure in 2 of the 6 patients. CONCLUSION: The rate of serious bleeding complications related to catheter insertion is low and usually associated with anticoagulation. Holding anticoagulation therapy for a minimum of 24 hours during the postoperative period should eliminate much of the risk. Coagulation parameters should also be obtained and corrected preoperatively.     

Evaluation of Hemoperitoneum Using a Single- vs Multiple-view Ultrasonographic Examination

Objective: To compare the sensitivities, specificities, and accuracies between a single-view ultrasonography (US) technique and a multiple-view technique for identifying hemoperitoneum in multiple-trauma patients.
Methods: Data from a prior prospective study of US for trauma diagnosis at a level I trauma center were retrospectively analyzed. A convenience sample of adult patients (≥ 18 years of age) who had presented with major blunt or penetrating torso trauma and had undergone rapid trauma US examinations to detect hemoperitoneum were reviewed. The US interpretations by emergency physicians had been recorded prior to obtaining other diagnostic tests. Five views were evaluated, including the right intercostal oblique view examining Morison's pouch. Evidence of free intraperitoneal fluid by exploratory laparotomy, CT, or diagnostic peritoneal lavage (DPL) was used as the criterion standard.
Results: Of the 245 patients entered into the study, 37 had free intraperitoneal fluid, confirmed by CT, DPL, or exploratory laparotomy. With the multiple-view technique, US was 87% (95% CI = 71%, 96%) sensitive, 100% (95% CI = 97%, 100%) specific, and 98% (95% CI = 95%, 100%) accurate. The single-view technique, evaluating only Morison's pouch, was 51% (95% CI = 34%, 68%) sensitive, 100% (95% CI = 98%, 100%) specific, and 93% (95%. CI = 89%, 96%) accurate.
Conclusions: An initial trauma US examination using a multiple-view technique is more sensitive than that using a single-view technique for detecting hemoperitoneum in trauma patients.     

Risk of recurrence of birth defects in Washington State

A population-based study was conducted using maternally-linked birth certificate records from Washington State for 1980–93 to evaluate the risk of birth defect occurrence among infants with pre-viously affected siblings, relative to infants whose siblings did not have birth defects. The risks of recurrence of similar and dissimilar defects were estimated, and the effects of change in paternity and/or city of residence were evaluated as proxies of genetic and environmental effects. At the first birth on record, 3322 women were identified in the linked certificates as giving birth to a child with a birth defect; 6620 women whose first birth did not result in an infant with a defect were randomly selected for comparison. Women with a malformed infant had an in-creased risk of having a malformed infant at the subsequent birth (Relative Risk = 1.9, [95% Confidence Interval (CI) = 1.5–2.4]), which did not vary by intervening changes in partner or residence. The risk of recurrence of the same general type of defect [RR = 11.7, 95% CI = 9.7–19.50] was much greater than that of occurrence of a dissimilar defect [RR = 1.5, 95% CI = 1.1–1.9]. This was consistent for all defect categories, and did not vary markedly by changes in partner or residence.     

The effect of aquatic therapy on functional mobility of infants and toddlers in early intervention.

PURPOSE: The purpose of this study was to determine the effect of aquatic therapy (AT) as an adjunct to home-based early intervention (EI) on differences in children's functional mobility. METHODS: Thirty-seven children of ages six to 30 months (x = 24.2; SD = 8.5) with delayed functional mobility participated in this study. The AT group (n = 15) received weekly AT in a community pool in addition to home-based EI with a physical therapist (PT) or occupational therapist (OT). A randomly selected comparison group (n = 22) received home-based EI with a PT or OT. Baseline and postintervention scores on the Gross Motor Subsection of the Mullen Scales of Early Learning were compared between the AT and comparison group. RESULTS: The AT group demonstrated significantly greater (p < 0.05) gains in functional mobility than the comparison group. CONCLUSION: AT is a useful adjunct to EI to improve children's functional mobility.     

The Significance of Histology and Morphometry in Predicting Lymph Node Metastases in Patients with Squamous Cell Carcinoma of the Vulva

The material consists of a series of 73 patients with squamous cell carcinoma of the vulva. The site and the size of the primary tumor and the histological status of the lymph nodes of the groin were known. Two pathologists evaluated nuclear hyperchromatism, nuclear polymorphism, histological differentiation, number of mitoses, inflammatory response, and vascular invasion and graded these parameters from one to three. The reliability of the histopathological grades evaluated by the κ coefficient showed considerable interobserver variation. Despite this a model which included the subjective parameter nuclear hyperchromatism could predict patients without lymph node metastases. The model consisted of patients with tumors which were not situated on the clitoris, were less than 40 mm in diameter, and exhibited only slight hyperchromatism. The model fitted 19 (26%) and 14 (19%) of the patients with two different pathologists evaluating the nuclear hyperchromatism and none of these patients had lymph node metastases. The quantitative parameter—mean nuclear volume—determined by morphometry was of no diagnostic value for the prediction of patients without groin node metastases at the time of operation.