Identification of a Dutch founder mutation in MUSK causing fetal akinesia deformation sequence

Fetal akinesia deformation sequence (FADS) refers to a clinically and genetically heterogeneous group of disorders with congenital malformations related to impaired fetal movement. FADS can result from mutations in CHRNG, CHRNA1, CHRND, DOK7 and RAPSN; however, these genes only account for a minority of cases. Here we identify MUSK as a novel cause of lethal FADS. Fourteen affected fetuses from a Dutch genetic isolate were traced back to common ancestors 11 generations ago. Homozygosity mapping in two fetuses revealed MUSK as a candidate gene. All tested cases carried an identical homozygous variant c.1724T>C; p.(Ile575Thr) in the intracellular domain of MUSK. The carrier frequency in the genetic isolate was 8%, exclusively found in heterozygous carriers. Consistent with the established role of MUSK as a tyrosine kinase that orchestrates neuromuscular synaptogenesis, the fetal myopathy was accompanied by impaired acetylcholine receptor clustering and reduced tyrosine kinase activity at motor nerve endings. A functional assay in myocytes derived from human fetuses confirmed that the variant blocks MUSK-dependent motor endplate formation. Taken together, the results strongly support a causal role of this founder mutation in MUSK, further expanding the gene set associated with FADS and offering new opportunities for prenatal genetic testing.     

The thickness of facial alveolar bone overlying healthy maxillary anterior teeth

Background: A facial bone (<2 mm) overlying maxillary anterior teeth may be prone to resorptive processes after extraction and immediate implant placement. A thin bone contributes to risk of bone fenestration, dehiscence, and soft‐tissue recession. This study measures the distance between the cemento‐enamel junction (CEJ) and alveolar bone crest and the thickness of facial alveolar bone at points 1 to 5 mm from the bone crest for the six maxillary anterior teeth. Methods : Sixty‐six tomographic scans (31 males and 35 females; aged 17 to 69 years; mean age: 39.9 years) of intact anterior maxilla were randomly selected and evaluated by two calibrated and independent examiners (MG and TP). Results: A high variation of CEJ–bone crest (0.8 to 7.2 mm) was detected. A significantly larger CEJ–bone crest was measured in smokers (P <0.05) and patients who were ≥50 years old (P <0.05). The average bone thickness at 3 mm from the CEJ for the maxillary right central incisor was 1.41 mm and for the maxillary left central incisor was 1.45 mm. For the maxillary right and left lateral incisors, the crestal bone thickness averaged 1.73 and 1.59 mm, respectively. For the maxillary right and left canines, the crestal bone thickness averaged 1.47 and 1.60 mm, respectively. Conclusions : The present study supports the finding of a predominantly thin facial bone overlying the six maxillary anterior teeth. Therefore, it is essential to make informed treatment decisions based on thorough site evaluation before immediate implant placement.     

EUS mini probes in diagnosis of cystic dystrophy of duodenal wall in heterotopic pancreas： A case report

Cystic dystrophy of the duodenal wall is a rare condition characterized by the development of cysts in heterotopic pancreatic tissue localized in the duodenal wall. A 38-year-old man was admitted to the hospital for abdominal pain and vomiting after food intake. The diagnosis of acute pancreatitis was initially suspected. Abdominal ultrasound examination revealed thickening of the second portion of duodenal wall within which, small cysts (diameter, less than 1 cm) were present in the vicinity of pancreatic head.The head of pancreas appeared enlarged (63 mm&#215;42 mm)and hypoechoic. Upper endoscopy and barium X-ray series were performed revealing a severe circumferential deformation, as well as 4 cm long stenosis of the second portion of the duodenum. CT examination revealed multiple cysts located in an enlarged, thickened duodenal wall with moderate to strong post-contrast enhancement. We suspected that patient had cystic dystrophy of duodenal wall developed in the heterotopic pancreas and diagnosis was confirmed by endoscopic ultrasound (EUS). Endoscopi cutrasound (EUS) revealed drcular stenosis from the duodenal bulb onwards. A twenty megaHertz mini-probe examination further showed diffuse (intramural) infiltration of duodenal wall limited to the submucosa and muscularis propria of the second portion of duodenum with multiple microcysts within the thickened mucosa and submucosa, a. Patient was successfully surgically treated and pancreatoduodenectomy was performed. The pathological examination confirmed a diagnosis of cystic dystrophy of a heterotopic pancreas.Endoscopic ultrasonography features allow preoperative diagnosis of cystic dystrophy of a heterotopic pancreas in duodenal wall, with inb‘alumina120 MHz mini probe sonography being more efficient in cases of luminal stenosis.     

Recurrent Hepatitis in Two Iranian Children: A Novel (Q166R) Mutation in EIF2AK3 Leading to Wolcott-Rallison Syndrome

Early-onset diabetes, liver dysfunction, growth retardation, spondyloepiphyseal dysplasia, and tendency to skeletal fractures due to osteopenia are characteristics of Wolcott-Rallison syndrome (WRS). Eukaryotic translation initiation factor 2α kinase (EIF2AK3) is the only known gene, which is responsible for this rare autosomal recessive disorder. Here, we report two siblings a girl and a boy with diabetes mellitus (DM) who presented in one and two months of age respectively. Recurrent self-limiting hepatitis developed later, and severe hepatic failure resulted in death of the first child. The second child visited was a 7.75 year old boy who had spondyloepiphyseal dysplasia and subclinical hypothyroidism besides DM and recurrent hepatitis. We suggested WRS for this patient, and it was confirmed by identification of a novel homozygous missense mutation (Q166R) in exon 3 of the EIF2AK3 gene. The aim of this report is to remind the possibility of WRS in isolated neonatal diabetes; while, the other clinical manifestations of this syndrome including its major symptom of recurrent hepatitis may appear later.     

Role of capsid sequence and immature nucleocapsid proteins p9 and p15 in Human Immunodeficiency Virus type 1 genomic RNA dimerization

HIV-1 genomic RNA (gRNA) dimerization is important for viral infectivity and is regulated by proteolytic processing of the Gag precursor protein (Pr55gag) under the direction of the viral protease. The processing occurs in successive steps and, to date, the step associated with formation of a wild-type (WT) level of gRNA dimers has not been identified. The primary cleavage divides Pr55gag into two proteins. The C-terminal polypeptide is termed NCp15 (NCp7-p1-p6) because it contains the nucleocapsid protein (NC), a key determinant of gRNA dimerization and packaging. To examine the importance of precursor polypeptides NCp15 and NCp9 (NCp7-p1), we introduced mutations that prevented the proteolytic cleavages responsible for the appearance of NCp9 or NCp7. Using native Northern blot analysis, we show that gRNA dimerization was impaired when both the secondary (p1-p6) and tertiary (p7-p1) cleavage sites of NCp15 were abolished, but unaffected when only one or the other site was abolished. Though processing to NCp9 therefore suffices for a WT level of gRNA dimerization, we also show that preventing cleavage at the p7-p1 site abolished HIV-1 replication. To identify the minimum level of protease activity compatible with a WT level of gRNA dimers, we introduced mutations Thr26Ser and Ala28Ser in the viral protease to partially inactivate it, and we prepared composite HIV-1 resulting from the cotransfection of various ratios of WT and protease-inactive proviral DNAs. The results reveal that a 30% processing of Pr55gag into mature capsid proteins (CA/CA-p2) yielded a WT level of gRNA dimers, while a 10% Pr55gag processing hardly increased gRNA dimerization above the level seen in protease-inactive virions. We found that full gRNA dimerization required less than 50% WT NC in complementation asssays. Finally, we show that if we destroy alpha helix 1 of the capsid protein (CA), gRNA dimerization is impaired to the same extent as when the viral protease is inactivated. Cotransfection studies show that this CA mutation, in contrast to the NC-disabling mutations, has a dominant negative effect on HIV-1 RNA dimerization, viral core formation, and viral replication. This represents the first evidence that a capsid mutation can affect HIV-1 RNA dimerization.     

Pre‐medication and renal pre‐conditioning: a role for alprazolam,atropine, morphine and promethazine

Four pre‐medication drugs are used to relieve pain, allay anxiety, reduce secretion and enhance hypnosis, were evaluated for their effects on ischemia reperfusion (I/R) injury which is one of the major complications of vascular and transplantation surgery. Right kidney was removed from female rats (210–250 g) 3 weeks before surgical procedure. Different doses of morphine (0.5, 2 and 5 mg/kg), promethazine (1, 2 and 5 mg/kg), atropine (0.1, 0.3 and 0.5 mg/kg) and alprazolam (0.08, 0.32 and 0.64 mg/kg) were administered subcutaneously 30 min before left renal artery occlusion and 6 h reperfusion. Left kidneys were processed for histological evaluations. Creatinine and BUN were measured in serum samples. Morphine, promethazine, atropine and alprazolam at all evaluated doses significantly decreased serum creatinine and BUN levels and histopathological scores. The effects of promethazine (1 mg/kg) and all doses of alprazolam were more potent than other pre‐medication drugs and doses. This study suggested a protective effect of these pre‐medication drugs on I/R injury. Although obvious studies are required, these findings may lead to effective therapies against I/R injury.     

Does electronic clinical microbiology results reporting influence medical decision making: a pre- and post-interview study of medical specialists

Background  

Clinicians view the accuracy of test results and the turnaround time as the two most important service aspects of the clinical microbiology laboratory. Because of the time needed for the culturing of infectious agents, final hardcopy culture results will often be available too late to have a significant impact on early antimicrobial therapy decisions, vital in infectious disease management. The clinical microbiologist therefore reports to the clinician clinically relevant preliminary results at any moment during the diagnostic process, mostly by telephone. Telephone reporting is error prone, however. Electronic reporting of culture results instead of reporting on paper may shorten the turnaround time and may ensure correct communication of results. The purpose of this study was to assess the impact of the implementation of electronic reporting of final microbiology results on medical decision making.