Children's Hospital Oakland Research Institute

About: Children's Hospital Oakland Research Institute is a based out in . It is known for research contribution in the topics: Population & Human leukocyte antigen. The organization has 1568 authors who have published 2480 publications receiving 203418 citations.

The identification of 5 alpha-reductase-2 and 17 beta-hydroxysteroid dehydrogenase-3 gene defects in male pseudohermaphrodites from a Turkish kindred.

Abstract: Male pseudohermaphroditism (MPH) is characterized by incomplete differentiation of male genitalia in the presence of testicular tissue. Enzymatic defects involving androgen synthesis or action are causes of MPH. We studied the molecular genetics of a large isolated inbred Turkish kindred with MPH due to either 5 alpha-reductase-2 (SRD5A2) or 17 beta-hydroxysteroid dehydrogenase-3 (17 beta HSD3) gene defects. Using single strand DNA conformational polymorphism analysis and DNA sequencing, a new mutation in exon 5 of SRD5A2 gene was detected in certain male pseudohermaphrodites from this kindred. This single base deletion (adenine) resulted in a frame shift at amino acid position 251 resulting in the addition of 23 amino acids at the carboxyl-terminal of this 254-amino acid isozyme. Transfection expression of the mutant isozyme in CV1 cells showed a complete loss of enzymatic activity in the conversion of [14C]testosterone to dihydrotestosterone, without a change in the messenger ribonucleic acid level compared to that of the wild-type isozyme. Analysis of the 17 beta HSD3 gene in other male pseudohermaphrodites from this kindred revealed a single point mutation (G-->A) at the boundary between intron 8 and exon 9, disrupting the splice acceptor site of exon 9. In this kindred, in addition to the identification of male pseudohermaphrodites with either a homozygous SRD5A2 or 17 beta HSD3 gene defect, other male pseudohermaphrodites were found to be genetically more complex: e.g. homozygous for the SRD5A2 defect and heterozygous for the 17 beta HSD3 defect, or homozygous for the 17 beta HSD3 defect and heterozygous for the SRD5A2 defect. Also, phenotypically normal carriers were identified with either one or both gene defects. Homozygous male pseudohermaphrodites with SRD5A2 or 17 beta HSD3 gene defects were phenotypically distinguishable by the presence of mild gynecomastia in the latter. Hormone data were consistent with the particular homozygous gene defect. In summary, we show 1) the novel existence of two gene defects, SRD5A2 and 17 beta HSD3, each causing MPH within a large isolated Turkish kindred; 2) that the two defects segregate independently and may be inherited from two different progenitors; and 3) analysis of a new mutation in exon 5 of SRD5A2 gene, supporting the functional importance of the carboxyl-terminal of 5 alpha-reductase-2 isozyme.

Genetic variability and linkage disequilibrium within the HLA‐DP region: analysis of 15 different populations

Abstract: In order to understand the forces governing the evolution of the genetic diversity in the HLA-DP molecule, polymerase chain reaction (PCR)-based methods were used to characterize genetic variation at the DPA1 and DPB1 loci encoding this heterodimer on 2,807 chromosomes from 15 different populations including individuals of African, Asian, Amerindian, Indian and European origin. These ethnically diverse samples represent a variety of population substructures and include small, isolated populations as well as larger, presumably admixed populations. Ten DPA1 and 39 DPB1 alleles were identified and observed on 87 distinct DP haplotypes, 34 of which were found to be in significant positive linkage disequilibrium in at least one population. Some haplotypes were found in all ethnic groups while others were confined to a single ethnic group or population. Strong positive global linkage disequilibrium (Wn) between DPA1 and DPB1 was present in all 15 populations. The African populations displayed the lowest values of Wn whereas the Amerindian populations displayed near absolute disequilibrium. Analysis of the distribution of haplotypes using the normalized deviate of the Ewens-Watterson homozygosity statistic, F, suggests that DP haplotypes encoding the functional heterodimer are subject to much lower degrees of balancing selection than other loci within the HLA region. Finally, neighbor joining tree analyses demonstrate the power of haplotype diversity for inferring the relationships between the different populations.

Marking Embryonic Stem Cells with a 2A Self-Cleaving Peptide: A NKX2-5 Emerald GFP BAC Reporter

Abstract: BackgroundFluorescent reporters are useful for assaying gene expression in living cells and for identifying and isolating pure cell populations from heterogeneous cultures, including embryonic stem (ES) cells. Multiple fluorophores and genetic selection markers exist; however, a system for creating reporter constructs that preserve the regulatory sequences near a gene's native ATG start site has not been widely available.MethodologyHere, we describe a series of modular marker plasmids containing independent reporter, bacterial selection, and eukaryotic selection components, compatible with both Gateway recombination and lambda prophage bacterial artificial chromosome (BAC) recombineering techniques. A 2A self-cleaving peptide links the reporter to the native open reading frame. We use an emerald GFP marker cassette to create a human BAC reporter and ES cell reporter line for the early cardiac marker NKX2-5. NKX2-5 expression was detected in differentiating mouse ES cells and ES cell-derived mice.ConclusionsOur results describe a NKX2-5 ES cell reporter line for studying early events in cardiomyocyte formation. The results also demonstrate that our modular marker plasmids could be used for generating reporters from unmodified BACs, potentially as part of an ES cell reporter library.

A potent oral P-selectin blocking agent improves microcirculatory blood flow and a marker of endothelial cell injury in patients with sickle cell disease.

Abstract: Abnormal blood flow accounts for most of the clinical morbidity of sickle cell disease (SCD) [1,2]. Most notably, occlusion of flow in the microvasculature causes the acute pain crises [3] that are the commonest cause for patients with SCD to seek medical attention [4] and major determinants of their quality of life [5]. Based on evidence that endothelial P-selectin is central to the abnormal blood flow in SCD we provide results from four of our studies that are germane to microvascular blood flow in SCD. A proof-of-principle study established that doses of heparin lower than what are used for anticoagulation but sufficient to block P-selectin improved microvascular blood flow inpatients with SCD. An in vitro study showed that Pentosan Polysulfate Sodium (PPS) had greater P-selectin blocking activity than heparin. A Phase I clinical study demonstrated that a single oral dose of PPS increased microvascular blood flow in patients with SCD. A Phase II clinical study that was not completed documented that daily oral doses of PPS administered for 8 weeks lowered plasma levels of sVCAM-1 and tended to improve microvascular blood flow in patients with SCD. These data support the concept that P-selectin on the microvascular endothelium is critical to both acute vascular occlusion and chronically impaired microvascular blood flow in SCD. They also demonstrate that oral PPS is beneficial to microvascular sickle cell blood flow and has potential as an efficacious agent for long-term prophylactic therapy of SCD.