Sex differences in spatial ability in children

There is considerable evidence that sex differences in spatial ability exist in adults, with males outperforming females at every age after puberty. It is difficult, however, to find sex differences in children younger than 13. This is due in part to the lack of adequate measures of spatial ability for use with children. We report the use of spatial tests for children that are similar to those that have shown large sex differences in adults and may be measuring ability comparable to adult spatial ability. Four tests of mental rotation and spatial visualization were given to two samples of children. The first sample consisted of 81 children (39 males and 42 females) aged 9 to 12 years. The second sample consisted of 42 children (21 males and 21 females) aged 9 to 13 years. Sex differences of .4–.6 standard deviations were found on three tests in both samples. These results indicate that sex differences in spatial ability can be found in preadolescents if appropriate tests are used. Measurement of these abilities in children facilitates the investigation of possible biological and sociocultural contributors to the sex differences in spatial ability.This study was supported by National Institutes of Health Grant HD19644 and NIH Biomedical Research Support Grant S07 RR05366-24.     

A single amino acid distinguishes the high-responder from the low-responder form of Fc receptor II on human monocytes.

The low-affinity Fc receptor on human peripheral blood monocytes (Fc gamma RIIA) is polymorphic with respect to its ability to bind murine IgG1. The two allelic forms of the receptor, high responder (HR) and low responder (LR), yield characteristic patterns after isoelectric focusing and react differently with the anti-Fc gamma RII monoclonal antibody (mAb), 41H16. We recently cloned cDNA encoding the extracellular domains of Fc gamma RIIA on monocytes from one HR and two LR donors, and found that they differed at only a single base. The cDNA isolated from the HR donor had a G at position 519 and would be expected to encode an aginine at residue 133 in the mature protein, while the cDNA isolated from both LR donors had an A at position 519 and would be expected to encode a histidine at the same residue. To determine whether this single amino acid substitution actually accounts for the functional polymorphism involving Fc gamma RIIA, we transfected COS cells with full-length HR and LR Fc gamma RIIA cDNA, and examined them for their ability to react with anti-Fc gamma RIIA mAb and to bind red blood cells (RBC) coated with either murine IgG2b or murine IgG1. Whereas COS cells transfected with either the HR cDNA or the LR cDNA reacted with the anti-Fc gamma RII mAb, IV.3, and bound murine IgG2b-coated RBC, only COS cells transfected with the HR cDNA formed rosettes with murine IgG1-coated RBC and reacted strongly with mAb 41H16. A total of nine LR donors were identified, and all were homozygous for the A substitution at position 519. We conclude that at an A at position 519 in the cDNA encoding Fc gamma RIIA is the primary molecular basis for the LR form of the receptor, and that the amino acid at residue 133 determines whether Fc gamma RIIA efficiently binds murine IgG1.     

An exome sequencing strategy to diagnose lethal autosomal recessive disorders

Rare disorders resulting in prenatal or neonatal death are genetically heterogeneous. For some conditions, affected fetuses can be diagnosed by ultrasound scan, but this is not usually possible until mid-gestation. There is often limited fetal DNA available for investigation. We investigated a strategy for diagnosing autosomal recessive lethal disorders in non-consanguineous pedigrees with multiple affected fetuses. Exome sequencing was performed to identify genes where each parent is heterozygous for a rare non-synonymous-coding or splicing variant. Putative pathogenic variants were tested for cosegregation in affected fetuses and unaffected siblings. In eight couples of European ancestry, we found on average 1.75 genes (range 0–4) where both parents were heterozygous for rare potentially deleterious variants. A proof-of-principle study detected heterozygous DYNC2H1 variants in a couple whose five fetuses had short-rib polydactyly. Prospective analysis of two couples with multiple pregnancy terminations for fetal akinesia syndrome was performed and a diagnosis was obtained in both the families. The first couple were each heterozygous for a previously reported GLE1 variant, p.Arg569His or p.Val617Met; both were inherited by their two affected fetuses. The second couple were each heterozygous for a novel RYR1 variant, c.14130-2A>G or p.Ser3074Phe; both were inherited by their three affected fetuses but not by their unaffected child. Biallelic GLE1 and RYR1 disease-causing variants have been described in other cases with fetal akinesia syndrome. We conclude that exome sequencing of parental samples can be an effective tool for diagnosing lethal recessive disorders in outbred couples. This permits early prenatal diagnosis in future pregnancies.     

Nontoxigenic Vibrio cholerae Non-O1/O139 Isolate from a Case of Human Gastroenteritis in the U.S. Gulf Coast

An occurrence of Vibrio cholerae non-O1/O139 gastroenteritis in the U.S. Gulf Coast is reported here. Genomic analysis revealed that the isolate lacked known virulence factors associated with the clinical outcome of a V. cholerae infection but did contain putative genomic islands and other accessory virulence factors. Many of these factors are widespread among environmental strains of V. cholerae, suggesting that there might be additional virulence factors in non-O1/O139 V. cholerae yet to be determined. Phylogenetic analysis revealed that the isolate belonged to a phyletic lineage of environmental V. cholerae isolates associated with sporadic cases of gastroenteritis in the Western Hemisphere, suggesting a need to monitor non-O1/O139 V. cholerae in the interest of public health.     

Human anti-acetylcholine receptor antibodies use variable gene segments analogous to those used in autoantibodies of various specificities

The production of autoantibodies to the nicotinic acetylcholine receptor are responsible for many of the neurological symptoms observed in myasthenia gravis. An understanding of the structural organization of the anti-receptor antibodies may help to define the role of these antibodies in the pathogenesis of this disease. The nucleotide sequences of the heavy and light chains of three human monoclonal anti-receptor antibodies isolated from peripheral blood lymphocytes from two patients with myasthenia gravis were analyzed. In addition, the structure of an anti-idiotypic antibody was studied. The V_H and V_L gene segments used in the anti-receptor antibodies appear to be derived from the same repertoire as gene segments that have been found in other autoantibodies isolated from patients with various autoimmune diseases. The IgM anti-receptor antibodies are direct copies of germline gene segments, while the structures of the IgG anti-receptor antibody and the anti-idiotypic antibody appear to be mutated suggesting that they have undergone antigenic selection.     

A novel method for selection of invasive tumor cells: Derivation and characterization of highly metastatic K1735 melanoma cell lines based onin vitro andin vivo invasive capacity

Tumor cell invasion of basement membranes is required at several steps in the process of metastasis. To study the genetic and biochemical events mediating invasion, a variant cell line (TK) was selected from the metastatic M2 K1735 murine melanoma cell line. A novel selection procedure was used, based onin vitro andin vivo invasion and growth upon basement membrane and stroma. Additionally, two extrapulmonary metastases of the TK cell line, TK-Eve and TK-Liver, were established as cell lines and characterized. The TK cell line demonstrates greater metastatic potentialin vivo and invasive abilityin vitro than the parent M2 cell line, confirming the validity of the selection procedure. In addition, the M2 and TK cell lines were examined for other cell functions involved in the metastatic process. Cellular growth rates and sensitivity to T lymphocyte and natural killer cell lysis were not determining factors in the metastatic potentials of the M2 and selected cell lines; possible macrophage contribution to metastatic behavior was noted. [³⁵S]methionine pulse labeling of protein synthesis and karyotypic analysis confirm the close relationship of parental and selected cell lines.Supported by contract NDI-23910.Supported by ACS Institution Grant IN-15-Y and NIH Grant MRC-5T34-GM08037.Was a fellow of the Jane Coffin Childs Memorial Fund for Medical Research. This investigation has been aided by a grant from the Jane Coffin Childs Memorial Fund for Medical Research. Also supported by NIH Postdoctoral Fellowship #HD06423.     

Birth plans—Impact on mode of delivery,obstetrical interventions,and birth experience satisfaction: A prospective cohort study

Objective

To examine whether the presence of a birth plan was associated with mode of delivery, obstetrical interventions, and patient satisfaction.

Methods

This was a prospective cohort study of singleton pregnancies greater than 34 weeks’ gestation powered to evaluate a difference in mode of delivery. Maternal characteristics, antenatal factors, neonatal characteristics, and patient satisfaction measures were compared between groups. Differences between groups were analyzed using chi‐squared for categorical variables, Fisher exact test for dichotomous variables, and Wilcoxon rank sum test for continuous or ordinal variables.

Results

Three hundred women were recruited: 143 (48%) had a birth plan. There was no significant difference in the risk of cesarean delivery for women with a birth plan compared with those without a birth plan (21% vs 16%, adjusted odds ratio [adjOR] 1.11 [95% confidence interval (CI) 0.61‐2.04]). Women with a birth plan were 28% less likely to receive oxytocin (P < .01), 29% less likely to undergo artificial rupture of membranes (P < .01), and 31% less likely to have an epidural (P < .01). There was no difference in the length of labor (P = .12). Women with a birth plan were less satisfied (P < .01) and felt less in control (P < .01) of their birth experience than those without a birth plan.

Conclusion

Women with and without a birth plan had similar odds of cesarean delivery. Though they had fewer obstetrical interventions, they were less satisfied with their birth experience, compared with women without birth plans. Further research is needed to understand how to improve childbirth‐related patient satisfaction.