Clarification of glycosylphosphatidylinositol anchorage of OTOANCORIN and human OTOA variants associated with deafness

Otoancorin (OTOA), encoded by OTOA, is required for the development of the tectorial membrane in the inner ear. Mutations in this gene cause nonsyndromic hearing loss (DFNB22). The molecular mechanisms underlying most DFNB22 remain poorly understood. Disruption of glycosylphosphatidylinositol (GPI) anchorage has been assumed to be the pathophysiology mandating experimental validation. From a Korean deaf family, we identified two trans OTOA variants (c.1320 + 5 G>C and p.Gln589ArgfsX55 [NM_144672.3]) . The pathogenic potential of c.1320 + 5 G>C was confirmed by a minigene splicing assay. To experimentally determine the GPI anchorage, wild‐type (WT) and mutant OTOA harboring p.Gln589ArgfsX55 were expressed in HEK293T cells. The mutant OTOA with p.Gln589ArgfsX55 resulted in an uncontrolled release of OTOA into the medium in contrast with phosphatidylinositol‐specific phospholipase C‐induced controlled release of WT OTOA from the cell surface. Together, the results of this reverse translational study confirmed GPI‐anchorage of OTOA and showed that downstream sequences from the 589th amino acid are critical for GPI‐anchorage.     

A case: control study of oro-facial clefts in Western Australia

A bstract — A case: control study was undertaken using all children with oro-facial clefts born between 1 January 1982 and 14 April 1984 and conceived in Western Australia (WA) — a total of 90 cases and 180 matched controls. Information on all cases and controls was obtained from hospital records and a postal questionnaire. A 92 per cent response rate was obtained from the mothers of affected children.
An excess of cleft lip with or without cleft palate (CL(P)) was confirmed for rural Western Australia and reasons for this finding proposed. Further information is presented on maternal age, parity, blood groups, paternal occupation, familial and syndromic clefts, maternal alcohol and cigarette consumption and history of previous miscarriages.     

Childhood Primary Care Services in Wyoming

Provision of childhood primary care services and differences between types of providers (family practice physicians, pediatricians, nurse practitioners, and physicians' assistants) were explored in this study. A mail survey was conducted in Wyoming using a questionnaire based on the recommendations from the U. S. Preventive Service Task Force. Sixty-one percent of the providers returned questionnaires. While some areas of assessment, screening, and treatment/counseling services were provided at high levels, many were not. Gaps exist particularly in the areas of behavioral and lifestyle assessment and treatment/counseling. Only small differences existed between types of providers. However, nurse practitioners and pediatricians were more likely to report that they followed recommendations, while physicians' assistants were least likely to report that they followed recommendations.     

Patterns of cortical input to the primary motor area in the marmoset monkey

In primates the primary motor cortex (M1) forms a topographic map of the body, whereby neurons in the medial part of this area control movements involving trunk and hindlimb muscles, those in the intermediate part control movements involving forelimb muscles, and those in the lateral part control movements of facial and other head muscles. This topography is accompanied by changes in cytoarchitectural characteristics, raising the question of whether the anatomical connections also vary between different parts of M1. To address this issue, we compared the patterns of cortical afferents revealed by retrograde tracer injections in different locations within M1 of marmoset monkeys. We found that the entire extent of this area is unified by projections from the dorsocaudal and medial subdivisions of premotor cortex (areas 6DC and 6M), from somatosensory areas 3a, 3b, 1/2, and S2, and from posterior parietal area PE. While cingulate areas projected to all subdivisions, they preferentially targeted the medial part of M1. Conversely, the ventral premotor areas were preferentially connected with the lateral part of M1. Smaller but consistent inputs originated in frontal area 6DR, ventral posterior parietal cortex, the retroinsular cortex, and area TPt. Connections with intraparietal, prefrontal, and temporal areas were very sparse, and variable. Our results demonstrate that M1 is unified by a consistent pattern of major connections, but also shows regional variations in terms of minor inputs. These differences likely reflect requirements for control of voluntary movement involving different body parts. J. Comp. Neurol. 522:811–843, 2014. © 2013 Wiley Periodicals, Inc.     

[11C]5-HTP and microPET are not suitable for pharmacodynamic studies in the rodent brain

The PET tracer [¹¹C]5-hydroxytryptophan ([¹¹C]5-HTP), which is converted to [¹¹C]5-hydroxytryptamine ([¹¹C]5-HT) by aromatic amino acid decarboxylase (AADC), is thought to measure 5-HT synthesis rates. But can we measure these synthesis rates by kinetic modeling of [¹¹C]5-HTP in rat? Male rats were scanned with [¹¹C]5-HTP (60 minutes) after different treatments. Scans included arterial blood sampling and metabolite analysis. 5-HT synthesis rates were calculated by a two-tissue compartment model (2TCM) with irreversible tracer trapping or Patlak analysis. Carbidopa (inhibitor peripheral AADC) dose-dependently increased [¹¹C]5-HTP brain uptake, but did not influence 2TCM parameters. Therefore, 10 mg/kg carbidopa was applied in all subsequent study groups. These groups included treatment with NSD 1015 (general AADC inhibitor) or p-chlorophenylalanine (PCPA, inhibitor of tryptophan hydroxylase, TPH). In addition, the effect of a low-tryptophan (Trp) diet was investigated. NSD 1015 or Trp depletion did not affect any model parameters, but PCPA reduced [¹¹C]5-HTP uptake, and the k₃. This was unexpected as NSD 1015 directly inhibits the enzyme converting [¹¹C]5-HTP to [¹¹C]5-HT, suggesting that trapping of radioactivity does not distinguish between parent tracer and its metabolites. As different results have been acquired in monkeys and humans, [¹¹C]5-HTP-PET may be suitable for measuring 5-HT synthesis in primates, but not in rodents.     

Patterns of afferent input to the caudal and rostral areas of the dorsal premotor cortex (6DC and 6DR) in the marmoset monkey

Corticocortical projections to the caudal and rostral areas of dorsal premotor cortex (6DC and 6DR, also known as F2 and F7) were studied in the marmoset monkey. Both areas received their main thalamic inputs from the ventral anterior and ventral lateral complexes, and received dense projections from the medial premotor cortex. However, there were marked differences in their connections with other cortical areas. While 6DR received consistent inputs from prefrontal cortex, area 6DC received few such connections. Conversely, 6DC, but not 6DR, received major projections from the primary motor and somatosensory areas. Projections from the anterior cingulate cortex preferentially targeted 6DC, while the posterior cingulate and adjacent medial wall areas preferentially targeted 6DR. Projections from the medial parietal area PE to 6DC were particularly dense, while intraparietal areas (especially the putative homolog of LIP) were more strongly labeled after 6DR injections. Finally, 6DC and 6DR were distinct in terms of inputs from the ventral parietal cortex: projections to 6DR originated preferentially from caudal areas (PG and OPt), while 6DC received input primarily from rostral areas (PF and PFG). Differences in connections suggest that area 6DR includes rostral and caudal subdivisions, with the former also involved in oculomotor control. These results suggest that area 6DC is more directly involved in the preparation and execution of motor acts, while area 6DR integrates sensory and internally driven inputs for the planning of goal‐directed actions. They also provide strong evidence of a homologous organization of the dorsal premotor cortex in New and Old World monkeys. J. Comp. Neurol. 522:3683–3716, 2014. © 2014 Wiley Periodicals, Inc.     

Cortical and thalamic projections to cytoarchitectural areas 6Va and 8C of the marmoset monkey: Connectionally distinct subdivisions of the lateral premotor cortex

We studied the afferent connections of two cytoarchitectural subdivisions of the caudolateral frontal cortex, areas 6Va and 8C, in marmoset monkeys. These areas received connections from the same set of thalamic nuclei, including main inputs from the ventral lateral and ventral anterior complexes, but differed in their patterns of corticocortical connections. Areas 8C and 6Va had reciprocal interconnections, and received similar proportions of afferents from premotor areas 6M and 6DC, and from the prefrontal cortex. However, area 8C received stronger inputs from frontal areas that have been implicated in oculomotor functions, whereas area 6Va received stronger projections from the primary motor area. Somatosensory projections to area 6Va were generally stronger than those to area 8C, and originated from several areas; in contrast, only the second somatosensory area (S2) sent major inputs to area 8C. Finally, although both 6Va and 8C received major inputs from the rostral posterior parietal cortex (putative homologs of areas PE, PF, and PFG), area 8C also received a variety of smaller connections from posterior midline, caudal posterior parietal, and extrastriate areas. Statistical analyses revealed that the pattern of connections of area 8C is more akin to that characterizing a premotor area, rather than a prefrontal area. We conclude that cytoarchitectural area 6Va in the marmoset is similar to ventral premotor areas identified in other simian primates, and that area 8C corresponds to a specialized subdivision of the caudal premotor complex where visual information for the guidance of movements is likely to be emphasized. J. Comp. Neurol. 523:1222–1247, 2015. © 2015 Wiley Periodicals, Inc.