Localization of the gene for familial primary pulmonary hypertension to chromosome 2q31-32.

Primary pulmonary hypertension (PPH), an often fatal disease, is characterized by elevated pulmonary artery pressures in the absence of a secondary cause. Endovascular occlusion in the smallest pulmonary arteries occurs by proliferation of cells and matrix, with thrombus and vasospasm. Diagnosis is often delayed because the initial symptoms of fatigue and dyspnea on exertion are nonspecific and definitive diagnosis requires invasive procedures. The average life expectancy after diagnosis is two to three years with death usually due to progressive right heart failure. The aetiology of the disease is unknown. Although most cases appear to be sporadic, approximately 6% of cases recorded in the NIH Primary Pulmonary Hypertension Registry are inherited in an autosomal dominant manner with reduced penetrance. Following a genome-wide search using a set of highly polymorphic short tandem repeat (STR) markers and 19 affected individuals from six families, initial evidence for linkage was obtained with two chromosome 2q markers. We subsequently genotyped patients and all available family members for 19 additional markers spanning approximately 40 centiMorgans (cM) on the long arm of chromosome 2. We obtained a maximum two-point lod score of 6.97 at theta = 0 with the marker D2S389; multipoint linkage analysis yielded a maximum lod score of 7.86 with the marker D2S311. Haplotype analysis established a minimum candidate interval of approximately 25 cM.

Exponential gain and saturation of a self-amplified spontaneous emission free-electron laser.

Self-amplified spontaneous emission in a free-electron laser has been proposed for the generation of very high brightness coherent x-rays. This process involves passing a high-energy, high-charge, short-pulse, low-energy-spread, and low-emittance electron beam through the periodic magnetic field of a long series of high-quality undulator magnets. The radiation produced grows exponentially in intensity until it reaches a saturation point. We report on the demonstration of self-amplified spontaneous emission gain, exponential growth, and saturation at visible (530 nanometers) and ultraviolet (385 nanometers) wavelengths. Good agreement between theory and simulation indicates that scaling to much shorter wavelengths may be possible. These results confirm the physics behind the self-amplified spontaneous emission process and forward the development of an operational x-ray free-electron laser.

Linkage of combined factors V and VIII deficiency to chromosome 18q by homozygosity mapping.

Combined Factors V and VIII deficiency is an autosomal recessive bleeding disorder identified in at least 58 families comprising a number of different ethnic groups. Affected patients present with a moderate bleeding tendency and have Factor V and Factor VIII levels in the range of 5-30% of normal. The highest frequency of the mutant gene is found in Jews of Sephardic and Middle Eastern origin living in Israel with an estimated disease frequency of 1:100,000. We sought to identify the gene responsible for combined Factors V and VIII deficiency using a positional cloning approach. Of 14 affected individuals from 8 unrelated Jewish families, 12 were the offspring of first-cousin marriages. After a genome-wide search using 241 highly polymorphic short tandem repeat (STR) markers, 13 of the 14 affected patients were homozygous for two closely linked 18q markers. Patients and all available family members were genotyped for 11 additional STRs spanning approximately 11 cM on the long arm of chromosome 18. Multipoint linkage analysis yielded a maximal log of the odds (LOD) score of 13.22. Haplotype analysis identified a number of recombinant individuals and established a minimum candidate interval of 2.5 cM for the gene responsible for combined Factors V and VIII deficiency. The product of this locus is likely to operate at a common step in the biosynthetic pathway for these two functionally and structurally homologous coagulation proteins. Identification of this gene should provide new insight into the biology of Factor V and Factor VIII production.

TGFbeta is active, and correlates with activators of TGFbeta, following porcine coronary angioplasty.

OBJECTIVE: Restenosis following angioplasty involves processes that may be influenced by local production of cytokines. We investigated the expression of active and total transforming growth factor beta (TGFbeta) following porcine coronary angioplasty (PTCA), and have correlated this with the expression of potential in vivo activators of TGFbeta: mannose-6-phosphate/insulin-like growth factor-II (M6P/IGF-II) receptor and thrombospondin-1. METHODS: Oversized porcine PTCA was performed and the arteries excised after selected intervals. Levels of in situ active and total (active plus latent) TGFbeta were determined using a modified plasminogen activator-inhibitor/luciferase bioassay. RESULTS: Levels of active TGFbeta significantly increased 2 h to 7 days after angioplasty, compared to non-injured controls. Levels returned to baseline by 28 days. Active TGFbeta in tissues adjacent to the injured artery did not change. Total TGFbeta was significantly higher than controls 2-6 h after injury. M6P/IGF-II receptor mRNA was upregulated between 6 h and 3 days after injury, with protein detectable at 3-28 days. Thrombospondin-1 was detected between 1 h and 14 days. CONCLUSIONS: We conclude that balloon injury causes an early rapid increase in levels of active TGFbeta, that correlates with the expression of TGFbeta activators. Thus, TGFbeta is a good potential target for anti-restenotic therapies.

Response of very small (2 mm) porcine coronary arteries to balloon angioplasty and stent implantation.

OBJECTIVE: To investigate the response of very small coronary arteries to stent deployment and balloon angioplasty. SETTING: Normal porcine coronary arteries. METHODS: 24 pigs underwent intervention to two main coronary arteries, in segments 2.0 mm in diameter, with balloons whose diameter was 2.5 mm at standard pressure. Twelve arteries received a BiodivYsio small vessel (SV) stent; 12 an NIR SV stent; 12 standard BiodivYsio stent, and 12 balloon only. The arteries were harvested at 28 days, fixed, embedded in plastic, and cut and ground in cross section. The injury score and histomorphometry were assessed. RESULTS: The BiodivYsio SV stent was associated with 20% less injury (p = 0.16), a 30% larger lumen (p = 0.13), and a 25% smaller neointima (p = 0.03) than the NIR SV stent, despite identical oversize. The standard BiodivYsio stent exhibited less recoil but 29% greater injury (p = 0.01), 59% more neointima (p = 0.00), and 18% less lumen (p = 0.27) than the BiodivYsio SV. Of all interventions, balloon only was associated with little injury, little neointima, major vessel shrinkage, and the largest lumen. CONCLUSION: Despite uniform oversize dilatation, both injury and response varied widely in very small porcine coronary arteries, depending on whether a stent or balloon was used, the stent design, and the number and/or thickness of struts. The response to different stent designs is considerable and is related to the degree of injury.

p38 Mitogen-activated protein kinase mediates the transcriptional induction of the atrial natriuretic factor gene through a serum response element. A potential role for the transcription factor ATF6.

In various cell types certain stresses can stimulate p38 mitogen-activated protein kinase (p38 MAPK), leading to the transcriptional activation of genes that contribute to appropriate compensatory responses. In this report the mechanism of p38-activated transcription was studied in cardiac myocytes where this MAPK is a key regulator of the cell growth and the cardiac-specific gene induction that occurs in response to potentially stressful stimuli. In the cardiac atrial natriuretic factor (ANF) gene, a promoter-proximal serum response element (SRE), which binds serum response factor (SRF), was shown to be critical for ANF induction in primary cardiac myocytes transfected with the selective p38 MAPK activator, MKK6 (Glu). This ANF SRE does not possess sequences typically required for the binding of the Ets-related ternary complex factors (TCFs), such as Elk-1, indicating that p38-mediated induction through this element may take place independently of such TCFs. Although p38 did not phosphorylate SRF in vitro, it efficiently phosphorylated ATF6, a newly discovered SRF-binding protein that is believed to serve as a co-activator of SRF-inducible transcription at SREs. Expression of an ATF6 antisense RNA blocked p38-mediated ANF induction through the ANF SRE. Moreover, when fused to the Gal4 DNA-binding domain, an N-terminal 273-amino acid fragment of ATF6 was sufficient to support trans-activation of Gal4/luciferase expression in response to p38 but not the other stress kinase, N-terminal Jun kinase (JNK); p38-activating cardiac growth promoters also stimulated ATF6 trans-activation. These results indicate that through ATF6, p38 can augment SRE-mediated transcription independently of Ets-related TCFs, representing a novel mechanism of SRF-dependent transcription by MAP kinases.

Polymorphism of adhesion molecule CD31 is not a significant risk factor for graft-versus-host disease.

Mismatch between bone marrow transplant (BMT) patient and donor for an amino acid polymorphism within the adhesion molecule CD31 has recently been reported to increase risk for the development of graft-versus-host disease (GVHD). We further examined this association in a larger series of 301 BMT patients (227 with grade III/IV GVHD and 74 with grade 0 GVHD) and their HLA-identical sibling donors. CD31 genotypes were determined by polymerase chain reaction and restriction endonuclease digestion. The role of mismatch at the CD31 locus in the development of GVHD was assessed by analyzing the extent of CD31 identity and CD31 compatibility among the grade 0 GVHD and grade III/IV GVHD sibling pairs. No significant association between CD31 mismatch and the development of severe GVHD was detected in our overall patient population. Sixty-three percent of grade III/IV GVHD sibling pairs and 69% of grade 0 GVHD sibling pairs had CD31 genotypes that were identical (P = .36, odds ratio = 1.30). In addition, neither the grade 0 GVHD group (P = .10) nor the grade III/IV GVHD group (P = .27) differed significantly from the expected probability of identity between sibling pairs. Mismatch at the CD31 polymorphism between recipients and donors showed no consistent association with the development of GVHD. Current evidence does not support the value of CD31 mismatch in the selection of BMT donors.