Involvement of Renin-Angiotensin System in Pressure-Flow Relationship: Role of Angiotensin-converting Enzyme Gene Polymorphism

Background: The renin-angiotensin system is involved in blood pressure regulation. The insertion/deletion (I/D) polymorphism of the angiotensin-converting enzyme (ACE) gene is known to be associated with variation of plasma and cellular ACE concentrations. Furthermore, changes in arterial function have been suggested to be associated to the DD genotype. The aim of the study was to investigate the arterial vascular response to a physiologic stimulus (i.e., flow) according to the I/D ACE gene polymorphism.

Methods: Sixty patients scheduled for coronary artery bypass grafting (n = 24) or valve surgery (n = 36) under normothermic cardiopulmonary bypass were genotyped in a blind manner by polymerase chain reaction. Mean arterial pressure was measured at pump flows ranging from 1 to 3 l [middle dot] min-1 [middle dot] m-2 by 0.25 l [middle dot] min-1 [middle dot] m-2 step each 15 s, to obtain a pressure-flow relation. Independent factors associated with the variation of the slope of the pressure-flow relation curve were assessed by multivariate analysis.

Results: We found a D allelic frequency of 0.54. Patients were separated in two groups (DD, n = 16;ID/II, n = 44). There were no significant difference with regard to preoperative and intraoperative data between the two groups. DD patients had their pressure-flow relation curves shifted upward (with higher pressures as flow increased), indicating a lesser decrease in vascular resistance. Furthermore, DD genotype was the only independent predictor of the slope of the curves (21.5 +/- 4.2 vs. 18.1 +/- 5 mmHg/[l [middle dot] min-1 [middle dot] m-2] for DD and ID/II, respectively;P = 0.02; values are mean +/-SD).     

Family-based case-control study of MAOA and MAOB polymorphisms in Parkinson disease.

Monoamine oxidase (MAO) is an enzyme regulating metabolism of neurotransmitters such as dopamine. Two distinct forms of enzyme, encoded by genes MAOA and MAOB located on the X chromosome, have been considered as possible factors in the pathogenesis of Parkinson disease (PD). Previous association studies of PD and MAO genes reported inconsistent results. In this study, we used a large family-based data set to test associations between MAO genes and a risk of PD. The data set includes 298 female discordant sibpairs and 348 male discordant sibpairs. For this study, all subjects analyzed were white and families with known parkin mutations were removed. We analyzed 15 single nucleotide polymorphisms (SNPs) and a dinucleotide repeat marker in the MAO genes. Association was found with the intron 13 SNP of MAOB in the female subset (P = 0.02). No significant association was found in the male subset. Our results add to the evidence of involvement of MAOB in PD and suggest that the effect may be stronger in women.     

Investigation of vibration‐induced artifact in clinical diffusion‐weighted imaging of pediatric subjects

It has been reported that mechanical vibrations of the magnetic resonance imaging scanner could produce spurious signal dropouts in diffusion‐weighted images resulting in artifactual anisotropy in certain regions of the brain with red appearance in the Directionally Encoded Color maps. We performed a review of the frequency of this artifact across pediatric studies, noting differences by scanner manufacturer, acquisition protocol, as well as weight and position of the subject. We also evaluated the ability of automated and quantitative methods to detect this artifact. We found that the artifact may be present in over 50% of data in certain protocols and is not limited to one scanner manufacturer. While a specific scanner had the highest incidence, low body weight and positioning were also associated with appearance of the artifact for both scanner types evaluated, making children potentially more susceptible than adults. Visual inspection remains the best method for artifact identification. Software for automated detection showed very low sensitivity (10%). The artifact may present inconsistently in longitudinal studies. We discuss a published case report that has been widely cited and used as evidence to set policy about diagnostic criteria for determining vegetative state. That report attributed longitudinal changes in anisotropy to white matter plasticity without considering the possibility that the changes were caused by this artifact. Our study underscores the need to check for the presence of this artifact in clinical studies, analyzes circumstances for when it may be more likely to occur, and suggests simple strategies to identify and potentially avoid its effects. Hum Brain Mapp 36:4745–4757, 2015. © 2015 Wiley Periodicals, Inc.     

Late Pleistocene age and archaeological context for the hominin calvaria from GvJm-22 (Lukenya Hill,Kenya)

Kenya National Museums Lukenya Hill Hominid 1 (KNM-LH 1) is a Homo sapiens partial calvaria from site GvJm-22 at Lukenya Hill, Kenya, associated with Later Stone Age (LSA) archaeological deposits. KNM-LH 1 is securely dated to the Late Pleistocene, and samples a time and region important for understanding the origins of modern human diversity. A revised chronology based on 26 accelerator mass spectrometry radiocarbon dates on ostrich eggshells indicates an age range of 23,576–22,887 y B.P. for KNM-LH 1, confirming prior attribution to the Last Glacial Maximum. Additional dates extend the maximum age for archaeological deposits at GvJm-22 to >46,000 y B.P. (>46 kya). These dates are consistent with new analyses identifying both Middle Stone Age and LSA lithic technologies at the site, making GvJm-22 a rare eastern African record of major human behavioral shifts during the Late Pleistocene. Comparative morphometric analyses of the KNM-LH 1 cranium document the temporal and spatial complexity of early modern human morphological variability. Features of cranial shape distinguish KNM-LH 1 and other Middle and Late Pleistocene African fossils from crania of recent Africans and samples from Holocene LSA and European Upper Paleolithic sites.For Late Pleistocene African populations of modern humans, the constellation of behavioral changes encapsulated in the transition from the Middle Stone Age (MSA) to the Later Stone Age (LSA) ∼70–20 kya represents a series of some of the most pronounced changes in the archaeological record before the adoption of domesticated animals and plants and the use of ceramics for cooking and storage. It is among LSA sites that the strongest parallels with ethnographic and historic foragers are observed. Typical archaeological signatures include lithic technologies focused on the production of microliths (small flakes, blades, and bladelets with one edge blunted or “backed”) from bipolar, single-, and opposed-platform cores; an increased use of ground-stone tools; and implements made of wood and bone. These new technologies occur with the appearance of material correlates of social identity and networks of long-distance exchange, including ostrich eggshell (OES) beads, ochre, and nonlocal stone raw material, as well as increased dietary breadth, all consistent with larger, more dense, or more interconnected populations (1–9).This same interval of ∼70–20 kya witnessed a number of human dispersals across Africa, with eastern Africa host to one or more candidate populations for the expansion of Homo sapiens out of Africa (10–15). However, the eastern African hominin fossil record for this interval is extremely sparse and poorly dated, and it consists largely of isolated teeth or highly fragmentary crania and postcrania (16–18). Here, we reassess the age and context of the Kenya National Museums Lukenya Hill Hominid 1 (KNM-LH 1) partial calvaria from site GvJm-22 at Lukenya Hill, Kenya, the only eastern African fossil hominin from a Last Glacial Maximum [LGM; 19–26.4 kya (19)] LSA archaeological context. We construct a revised accelerator mass spectrometry (AMS) radiocarbon chronology built on 26 new dates on OES fragments. The revised chronology confirms the LGM age of KNM-LH 1 and expands the maximum age of the site to beyond the limits of the radiocarbon method. Increased radiometric age is consistent with new technological analyses that demonstrate previously unrecognized MSA elements that indicate assemblages spanning the MSA/LSA transition from deposits underlying KNM-LH 1. Morphometric analyses using a robust comparative dataset demonstrate the variability among African Late Pleistocene hominins, including candidate populations for out-of-Africa dispersals. They indicate that KNM-LH 1 is distinct from (i) modern Africans, (ii) H. sapiens from Holocene LSA sites, and (iii) European Upper Paleolithic modern humans, suggesting that it may sample a now extinct lineage.     

Rehabilitation Regimens Following Surgical Repair of Extensor Tendon Injuries of the Hand—A Systematic Review of Controlled Trials

There is no consensus on the most effective rehabilitation regimen following extensor tendon repair of the hand. This systematic review evaluates the outcomes of the various regimens. The Cochrane, MEDLINE, EMBASE, CINAHL, AMED, PEDro, OTseeker databases were searched for any prospective randomised clinical trials comparing rehabilitation regimens for acute extensor tendon injuries in adults. Five papers met the inclusion criteria. The regimens were static immobilisation, dynamic splinting and early active motion (EAM). There was no standard format of reporting. The sample size ranged from 27 to 100 patients. The duration of follow-up ranged from 8 to 24 weeks. Overall, patients’ total active motion improved with time. Early mobilisation regimens (active and passive) achieve quicker recovery of motion than static immobilisation but the long-term outcome appears similar. Given the comparable outcomes between dynamic splinting and EAM, we therefore favour EAM which is simpler and more convenient.

Electronic supplementary material

The online version of this article (doi:10.1007/s12593-012-0075-x) contains supplementary material, which is available to authorized users.