The spectrum of mutations in UBE3A causing Angelman syndrome

Angelman syndrome (AS) is characterized by mental retardation, absence of speech, seizures and motor dysfunction. AS is caused by maternal deletions for chromosome 15q11-q13, paternal uniparental disomy (UPD), imprinting defects or loss-of-function mutations in the UBE3A locus which encodes E6-AP ubiquitin-protein ligase. The UBE3A gene is imprinted with paternal silencing in human brain and similar silencing of the Ube3a locus in Purkinje cells and hippocampal neurons in the mouse. We have sequenced the major coding exons for UBE3A in 56 index patients with a clinical diagnosis of AS and a normal DNA methylation pattern. The analysis identified disease-causing mutations in 17 of 56 patients (30%) including 13 truncating mutations, two missense mutations, one single amino acid deletion and one stop codon mutation predicting an elongated protein. Mutations were identified in six of eight families (75%) with more than one affected case, and in 11 of 47 isolated cases (23%); no mutation was found in one family with two siblings, one with a typical and one with an atypical phenotype. Mutations were de novo in nine of the 11 isolated cases. An amino acid polymorphism of threonine substituted for alanine at codon 178 was identified, and a 3 bp length polymorphism was found in the intron upstream of exon 8. In all informative cases, phenotypic expression was consistent with imprinting with a normal phenotype when a mutation was on the paternal chromosome and an AS phenotype when a mutation was on the maternal chromosome. Laboratory diagnosis and genetic counseling for AS are complex, and mutation analysis is valuable in clinically typical AS patients with a normal methylation analysis.      

Prevalence and factors associated with tuberculosis treatment outcome among hazardous or harmful alcohol users in public primary health care in South Africa

Background

Tuberculosis (TB) remains a chronic infectious disease with high morbidity and mortality.

Objective

The aim of this study was to assess the prevalence and associated factors of tuberculosis treatment failure, death and default among hazardous or harmful alcohol users.

Method

We conducted a prospective study with TB patients in 40 public health clinics in three districts in South Africa. All consecutively new tuberculosis and retreatment patients presenting at the 40 primary health care facilities with hazardous or harmful alcohol use were included in this study. Logistic regression was used to assess determinants of TB treatment failure, death and default.

Results

The findings of our study showed that 70% of TB patients were either cured or had completed their TB treatment by the end of 6 months. In multivariate analysis participants living in a shack or traditional housing (Odds Ratio=OR: 0.63, Confidence Interval=CI: 0.45–0.89), being a TB retreatment patient (OR: 1.61, CI: 1.15–2.26) and residing in the eThekwini district (OR: 1.82, CI: 1.27–2.58) were significant predictors of treatment failure, death and default.

Conclusion

A high rate of treatment failure, death and default were found in the TB patients. Several factors were identified that can guide interventions for the prevention of treatment failure, death and default.     

Accuracy of spatial localization depending on head posture in a perturbed gravitoinertial force field

Spatial orientation is crucial when subjects have to accurately reach memorized visual targets. In previous studies modified gravitoinertial force fields were used to affect the accuracy of pointing movements in complete darkness without visual feedback of the moving limb. Target mislocalization was put forward as one hypothesis to explain this decrease in accuracy of pointing movements. The aim of this study was to test this hypothesis by determining the accuracy of spatial localization of memorized visual targets in a perturbed gravitoinertial force field. As head orientation is involved in localization tasks and carrying relevant sensory systems (visual, vestibular and neck muscle proprioceptive), we also tested the effect of head posture on the accuracy of localization. Subjects (n=10) were seated off-axis on a rotating platform (120 degrees s(-1)) in complete darkness with the head fixed (head-fixed session) or free to move (head-free session). They were required to report verbally the egocentric spatial localization of visual memorized targets. They gave the perceived target location in direction (i.e. left or right) and in amplitude (in centimeters) relative to the direction they thought to be straight ahead. Results showed that the accuracy of visual localization decreased when subjects were exposed to inertial forces. Moreover, subjects localized the memorized visual targets more to the right than their actual position, that was in the direction of the inertial forces. With further analysis, it appeared that this shift of localization was concomitant with a shift of the visual straight ahead (VSA) in the opposite direction. Thus, the modified gravitoinertial force field led to a modification in the orientation of the egocentric reference frame. Furthermore, this shift of localization increased when the head was free to move while the head was tilted in roll toward the center of rotation of the platform and turned in yaw in the same direction. It is concluded that the orientation of the egocentric reference frame was influenced by the gravitoinertial vector.     

Impact of Audits and Multifaceted Intervention on Vaginal Birth After Caesarean: Secondary Analysis of the QUARISMA Trial

Objectives

This study estimated the effect that a multifaceted intervention aiming to improve the quality of obstetrical care and reduce Caesarean section (CS) had on the rate of vaginal birth after Caesarean (VBAC).

Human hematopoiesis in SCID mice implanted with human adult cancellous bone

The persistence of hematopoietic cells from human adult cancellous bone fragments implanted subcutaneously into CB-17 scid/scid mice was studied. Recipient mice received either no pretreatment (control group) or pretreatment with 3 Gy total-body irradiation and anti-asialo GM1 sera (ASGM1; pretreated group) before implantation. Pretreated severe combined immunodeficient (SCID) mice implanted with human bone were subsequently given ASGM1 every 7 days for the duration of the experiments. At 12 weeks postimplantation, flow cytometry of cells from pretreated and control animal tissues detected human CD45+ cells in the mouse spleen (mean, 7.8% and 3.4% positive cells, pretreated and control animals, respectively), bone marrow (BM; mean, 16.5% and 4.8% positive cells, respectively), and blood (mean, 5.5% and < 2% positive cells, respectively), and in the implanted human bone (73% and 8.9% positive cells, respectively). At 12 weeks, pretreated mice had human granulocyte-macrophage colony-forming cells (GM-CFC) and burst-forming units-erythrocyte (BFU-E) in the implanted human bone in the murine BM and in some of the spleens. The spleens also had extensive infiltration of human B cells and macrophages. Mean serum levels of human IgG in pretreated animals were 14 micrograms/mL during weeks 6 to 12, compared with trace levels (< 1 microgram/mL) in control mice. Bone from patients with acute myeloblastic leukemia (AML) was also implanted in pretreated SCID mice, and retrieved at 8 weeks for analysis. Comparison of preimplantation and implanted samples showed that the original histology was maintained, and massive infiltration of human CD68+ cells was observed in the mice spleens and BM. Implantation of AML bone in SCID mice facilitates analysis of in situ AML cell interaction with stromal cells in the leukemic state, and therapies against AML can be tested in this system, especially the selective killing of AML cells in the presence of other BM cells. Furthermore, this model requires no exogenous administration of cytokines to maintain human hematopoiesis with both normal or AML bone. Because the structure and function of both normal and diseased human adult bone is maintained, this animal model should facilitate investigation of both normal human hematopoiesis and hematopoietic malignancies.     

Occlusion during iliac angioplasty: a salvageable complication

During transluminal dilation of the iliac artery, occlusion resulting from dissection occurred in four patients. In all four, the deteriorating clinical findings prompted surgical intervention. In three patients, Fogarty balloon catheters easily passed the occluded segments and specimens much the same as surgical endarterectomy specimens were retrieved. A clamp was used to retrieve the dissected portion of the vessel wall in the fourth patient. Three of four vessels have remained patent for 18 months, 18 months, and 6 months, respectively. One patient underwent bypass surgery 4 months after the occlusion episode for recurrent stenosis in a segment of vessel above the occluded segment, which had also been dilated during the same procedure. It is therefore possible in some cases to salvage vessels occluded during angioplasty, making it unnecessary to resort to aortofemoral or other type of bypass.     

Bronchobiliary fistula: complete percutaneous treatment with biliary drainage and stricture dilation

Percutaneous transhepatic cholangiography was performed on an 18-year-old man who presented with jaundice and cholangitis 19 months after right hepatic lobe resection. The cholangiogram demonstrated a bronchobiliary fistula and a stricture of the common hepatic duct. Percutaneous therapy consisting of biliary drainage and balloon dilation cholangioplasty was successful in eradicating the fistula and reestablishing normal bile flow.     

拟胆碱药物对赛拉嗪镇静效应的拮抗作用

以小鼠为实验对象,观察了拟胆碱药物对赛拉嗪镇静效应的影响,催醒宁(0.25～1.0mg·kg^-1),溴代胆碱(100～300 mg·kg^-1)以及槟榔碱(1.0～5.0 mg·kg^-1),均可显著拮抗赛拉嗪的镇静效应。催醒宁(0.25 mg·kg^-1和密胆碱(3μg icv)分别使赛拉嗪镇静效应量效曲线显著右移和左移。结果提示,赛拉嗪对中枢胆碱能系统功能产生抑制作用,在拮抗赛拉嗪镇静,以及赛拉嗪复合麻醉的催醒方面,催醒宁可能有潜在的应用价值。