Mutations in PLOD2 cause autosomal-recessive connective tissue disorders within the Bruck syndrome-Osteogenesis imperfecta phenotypic spectrum

PLOD2 and FKBP10 are genes mutated in Bruck syndrome (BS), a condition resembling osteogenesis imperfecta (OI), but that is also typically associated with congenital joint contractures. Herein, we sought mutations in six consanguineous BS families and detected changes in either PLOD2 or FKBP10 in all cases. Two probands were found with a homozygous frameshift mutation in the alternative exon 13a of PLOD2, indicating that specific inactivation of the longer protein isoform encoded by this gene is sufficient to cause BS. In addition, by homozygosity mapping, followed by a candidate gene approach, we identified a homozygous donor splice site mutation in PLOD2 in a patient with autosomal‐recessive OI (AR‐OI). Screening of additional samples also revealed compound heterozygous mutations in PLOD2 in two brothers, one affected with mild AR‐OI and the other with mild BS. Thus, PLOD2 in addition to causing BS is also associated with AR‐OI phenotypes of variable severity. Hum Mutat 33:1444–1449, 2012. © 2012 Wiley Periodicals, Inc.     

Investigation of central pain processing in shoulder pain: converging results from 2 musculoskeletal pain models

Recent reports suggest deficits in conditioned pain modulation (CPM) and enhanced suprathreshold heat pain response (SHPR) potentially play a role in the development of chronic pain. The purpose of this study was to investigate whether central pain processing was altered in 2 musculoskeletal shoulder pain models. The goals of this study were to determine whether central pain processing: 1) differs between healthy subjects and patients with clinical shoulder pain; 2) changes with induction of exercise-induced muscle pain; and 3) changes 3 months after shoulder surgery. Fifty-eight patients with clinical shoulder pain and 56 age- and sex-matched healthy subjects were included in these analyses. The healthy cohort was examined before inducing EIMP, and 48 and 96 hours later. The clinical cohort was examined before shoulder surgery and 3 months later. CPM did not differ between the cohorts, however; SHPR was elevated for patients with shoulder pain compared to healthy controls. Induction of acute shoulder pain with EIMP resulted in increased shoulder pain intensity but did not change CPM or SHPR. Three months following shoulder surgery, clinical pain intensity decreased but CPM was unchanged from preoperative assessment. In contrast, SHPR was decreased and showed values comparable with healthy controls at 3 months. Therefore, the present study suggests that: 1) clinical shoulder pain is associated with measurable changes in central pain processing; 2) exercise-induced shoulder pain did not affect measures of central pain processing; and 3) elevated SHPR was normalized with shoulder surgery. Collectively our findings support neuroplastic changes in pain modulation were associated with decreases in clinical pain intensity only, and could be detected more readily with thermal stimuli. PERSPECTIVE: Longitudinal studies involving quantitative sensory testing are rare. In exploring 2 musculoskeletal shoulder pain models (exercise-induced muscle pain and surgical pain), conditioned pain modulation was unchanged from pre- to post-assessment in both models. Suprathreshold heat pain response decreased after shoulder surgery and was comparable to healthy controls, suggesting this measure may be sensitive to decreases in clinical pain intensity.     

Usefulness of severity scores in patients with suspected infection in the emergency department: a systematic review

Background

Score systems for severity of illness and organ dysfunction have been validated and used as tools to predict the risk of death in intensive care unit (ICU) patients, but their usefulness in patients with suspected infection in the emergency department (ED) or hospital ward is unclear.

Objectives

The objective of this systematic review was to establish the accuracy of score systems in the prediction of mortality in patients with suspected infection in hospital settings compared to the ICU.

Methods

Three researchers independently performed a systematic search and a review of related articles and their references using the PubMed database. The articles were selected by consensus, based on previously defined inclusion and exclusion criteria.

Results

In total, 21 studies were included, 19 of which were carried out in the ED. The researchers found that the operative characteristics to evaluate the accuracy (calibration and discrimination) of the different scores were insufficiently assessed in most studies. Only two studies evaluated the calibration, using the Hosmer-Lemeshow goodness-of-fit test, and less than half of the studies evaluated the discrimination, using the area under the receiver operator characteristics curve.

Conclusions

The reviewed literature did not provide enough information to assess the accuracy of the prognostic models in patients with suspected infection admitted to the ED and hospital ward. Some reports suggest a better accuracy with new scores like the MEDS (Mortality in Emergency Department Sepsis score), but the results are not consistent.     

Leishmania (Viannia) species identification on clinical samples from cutaneous leishmaniasis patients in Peru: assessment of a molecular stepwise approach

We present an algorithm based on three PCR assays for Leishmania (Viannia) species identification and assessed its performance using 70 specimens from Peruvian patients. The succession of the assayed targets can be ordered according to species prevalence. Sequential progression through the algorithm reduced the number of samples here studied by approximately 30% after each step.     

SOD1-N196 mutation in a family with amyotrophic lateral sclerosis

Introduction

N19S mutation is produced by substitution in the 139 position of SOD1 and was described by Mayeux in a patient with amyotrophic lateral sclerosis (ALS). He suggested that it did not have a causal effect as it was found in asymptomatic and sporadic cases. Other authors in later articles did not agree.

Material and methods

We describe a family with 4 members with ALS patients and attempt to find the carrier of the N19S mutation of the propositus. Molecular studies were performed on 15 members of the family of a different order.

Results

The ALS cases were found in the maternal line of the propositus. The presence of the mutation was detected in 3 people, the other two were asymptomatic. One of patients with ALS in the family, who died previously, did not have the mutation. Two of the sons of this case and another of the other case did not show it. On the other hand, N19S mutation was only present in paternal branch of the propositus, where there were no cases.

Conclusion

The described family supports the hypothesis by Mayeux and against that mutation N19S has pathological consequences, since mutation is only in the family line where there are no cases with ALS. In consequence, although the described case is included as a familiar form, it cannot be attributed to the mutation, and its relationship with N19S should be considered as casual.     

Multiple phenotypes in Huntington disease mouse neural stem cells

Neural stem (NS) cells are a limitless resource, and thus superior to primary neurons for drug discovery provided they exhibit appropriate disease phenotypes. Here we established NS cells for cellular studies of Huntington's disease (HD). HD is a heritable neurodegenerative disease caused by a mutation resulting in an increased number of glutamines (Q) within a polyglutamine tract in Huntingtin (Htt). NS cells were isolated from embryonic wild-type (Htt(7Q/7Q)) and "knock-in" HD (Htt(140Q/140Q)) mice expressing full-length endogenous normal or mutant Htt. NS cells were also developed from mouse embryonic stem cells that were devoid of Htt (Htt(-/-)), or knock-in cells containing human exon1 with an N-terminal FLAG epitope tag and with 7Q or 140Q inserted into one of the mouse alleles (Htt(F7Q/7Q) and Htt(F140Q/7Q)). Compared to Htt(7Q/7Q) NS cells, HD Htt(140Q/140Q) NS cells showed significantly reduced levels of cholesterol, increased levels of reactive oxygen species (ROS), and impaired motility. The heterozygous Htt(F140Q/7Q) NS cells had increased ROS and decreased motility compared to Htt(F7Q/7Q). These phenotypes of HD NS cells replicate those seen in HD patients or in primary cell or in vivo models of HD. Huntingtin "knock-out" NS cells (Htt(-/-)) also had impaired motility, but in contrast to HD cells had increased cholesterol. In addition, Htt(140Q/140Q) NS cells had higher phospho-AKT/AKT ratios than Htt(7Q/7Q) NS cells in resting conditions and after BDNF stimulation, suggesting mutant htt affects AKT dependent growth factor signaling. Upon differentiation, the Htt(7Q/7Q) and Htt(140Q/140Q) generated numerous Beta(III)-Tubulin- and GABA-positive neurons; however, after 15 days the cellular architecture of the differentiated Htt(140Q/140Q) cultures changed compared to Htt(7Q/7Q) cultures and included a marked increase of GFAP-positive cells. Our findings suggest that NS cells expressing endogenous mutant Htt will be useful for study of mechanisms of HD and drug discovery.     

No evidence for additional blood-brain barrier P-glycoprotein dysfunction in Alzheimer's disease patients with microbleeds

Decreased blood-brain barrier P-glycoprotein (Pgp) function has been shown in Alzheimer's disease (AD) patients using positron emission tomography (PET) with the radiotracer (R)-[(11)C]verapamil. Decreased Pgp function has also been hypothesized to promote cerebral amyloid angiopathy (CAA) development. Here, we used PET and (R)-[(11)C]verapamil to assess Pgp function in eighteen AD patients, of which six had microbleeds (MBs), presumably reflecting underlying CAA. No differences were found in binding potential and nonspecific volume of distribution of (R)-[(11)C]verapamil between patient groups. These results provide no evidence for additional Pgp dysfunction in AD patients with MBs.