Identification of structural mutations in the fifth domain of apolipoprotein H (beta 2-glycoprotein I) which affect phospholipid binding

Apolipoprotein H (apoH), also known as beta 2-glycoprotein-I, is considered to be a cofactor for the binding of certain antiphospholipid autoantibodies to negatively charged phospholipids. Genetically determined structural abnormalities in the lipid binding domain(s) of apoH can affect its ability to bind lipid and consequently the production of the autoantibodies. In this study we have identified two common structural mutations at codons 316 and 306 in the fifth domain of apoH which rendered apoH unable to bind to negatively charged phosphatidylserine (PS). The missense mutation at codon 316 (TGG --> TCG) replaces Trp316 with Ser316 and disrupts the integrity of four highly conserved hydrophobic amino acids sequence at positions 313-316, which is a potential protein-lipid hydrophobic interaction site. The missense mutation at codon 306 (TGC --> GGC) involves the substitution of Cys306 by Gly306 which causes the disruption of a disulfide bond between Cys281 and Cys306 and affects the normal configuration of the fifth domain of apoH that appears to be critical for clustering positively charged amino acids along with four hydrophobic amino acids sequence. ApoH from the two homozygotes (Ser316/Ser316) and all seven compound heterozygotes (Ser316/Gly306) failed to bind to PS; all heterozygotes at one or the other sites and wild type showed normal PS binding. These data indicate that the fifth domain of apoH harbors the lipid binding region. An estimated 2 million Caucasians in the United States, who are compound heterozygotes for the two mutations, may be precluded from producing apoH-dependent antiphospholipid autoantibodies.      

Mouse choroideremia gene mutation causes photoreceptor cell degeneration and is not transmitted through the female germline

Choroideremia (CHM) is an X-linked progressive eye disorder which results from defects in the human Rab escort protein-1 (REP-1) gene. A gene targeting approach was used to disrupt the mouse chm/rep-1 gene. Chimeric males transmitted the mutated gene to their carrier daughters but, surprisingly, these heterozygous females had neither affected male nor carrier female offspring. The targeted rep-1 allele was detectable, however, in male as well as female blastocyst stage embryos isolated from a heterozygous mother. Thus, disruption of the rep-1 gene gives rise to lethality in male embryos; in female embryos it is only lethal if the mutation is of maternal origin. This observation can be explained by preferential inactivation of the paternal X chromosome in murine extraembryonic membranes suggesting that expression of the rep-1 gene is essential in these tissues. In both heterozygous females and chimeras the rep-1 mutation causes photoreceptor cell degeneration. Consequently, conditional rescue of the embryonic lethal phenotype of the rep-1 mutation may provide a faithful mouse model for choroideremia.      

Linkage analysis of candidate regions for coeliac disease genes

A strong HLA association is seen in coeliac disease [specifically to the DQ(alpha1*0501,beta1*0201 heterodimer], but this cannot entirely account for the increased risk seen in relatives of affected cases. One or more genes at HLA-unlinked loci also predispose to coeliac disease and are probably stronger determinants of disease susceptibility than HLA. A recent study has proposed a number of candidate regions on chromosomes 6p23 (distinct from HLA), 6p12, 3q27, 5q33.3, 7q31.3, 11p11, 15q26, 19p13.3, 19q13.1, 19q13.4 and 22cen for the location of a non-HLA linked susceptibility gene. We have examined these regions in 28 coeliac disease families by linkage analysis. There was excess sharing of chromosome 6p markers, but no support for a predisposition locus telomeric to HLA. No significant evidence in favour of linkage to coeliac disease was obtained for chromosomes 3q27, 5q33.3, 7q31.3, 11p11, 19p13.3, 19q13.1, 19q13.4 or 22cen. There was, however, excess sharing close to D15S642. The maximum non-parametric linkage score was 1.99 (P = 0.03). Although the evidence for linkage of coeliac disease to chromosome 15q26 is not strong, the well established association between coeliac disease and insulin dependent diabetes mellitus, together with the mapping of an IDDM susceptibility locus (IDDM3) to chromosome 15q26, provide indirect support for this as a candidate locus conferring susceptibility to coeliac disease in some families.      

The cost of infertility diagnosis and treatment in Canada in 1995

The objectives of this study were to estimate the direct cost of infertility management, including diagnosis and treatment, in Canada during 1995, and the relative cost per live birth by treatment category. The analysis was based on the following estimates: the prevalence of infertility in Canada in 1995; the volume and distribution of infertility services; and the effectiveness and cost of specific infertility treatments. In 1995 there were approximately 330,000 couples experiencing infertility in Canada. It is estimated that <50% (150,000) sought medical advice or treatment during that year. A total of 13 diagnostic and treatment categories account for nearly all of the treatments received, and these categories form the treatment model. The cost of treatment per live birth ranges from Cdn$650 for clomiphene treatment of unexplained infertility to Cdn$41,000 for in-vitro fertilization. For a hypothetical group of 100 couples, the annual cost of diagnosis and treatment would be Cdn$77,000 and Cdn$200,000 respectively for a total of Cdn$277,000, or an average of Cdn$2770 per couple. After 1 year of treatment, it is expected that 26 of these 100 couples would achieve a live birth. The total annual cost of infertility management in Canada, estimated to be approximately Cdn$415 million, is 0.6% of the annual cost of health care.      

Pentoxifylline versus placebo in the treatment of infertility associated with minimal or mild endometriosis: a pilot randomized clinical trial

The present study is the first prospective randomized controlled trial of the effect of pentoxifylline on future fertility in infertile women with asymptomatic minimal or mild endometriosis. After completion of a basic infertility workup and laparoscopy, patients were entered into the study and randomly allocated to receive either a 12 month course of oral pentoxifylline (800 mg/day) (n = 30) or an oral placebo (n = 30). Those patients with other infertility factors were included in the study only if the factors were correctable and ultimately determined to be non-contributory. Life-table analysis was used to compare pregnancy rates between the two groups over a 12 month period that started immediately after laparoscopy. The 12 month actuarial overall pregnancy rates were 31 and 18.5% in the pentoxifylline and placebo groups respectively. However, this difference was not statistically significant by the chi(2)-test. Similarly, the Cox regression method showed no differences between the hazard of pregnancy in the two groups studied (odds ratio, 0.56; 95% confidence interval, 0.18-1.67). Therefore, there is no evidence from this study that immunomodulation with pentoxifylline aids fertility in those women with minimal or mild endometriosis. Further studies including more infertile patients with endometriosis are desirable in order to confirm our results.      

Interference between work and outside-work demands relative to health: unwinding possibilities among full-time and part-time employees

Background: Demands from work and home may interfere with one another and the stress engendered by that can be detrimental to health. Purpose: To study the relationship between experienced interference and subjective health, and address the impact of unwinding on these associations. Method: Questionnaire data from a representative sample of the Swedish population are used considering full-time and part-time employed women and men aged 25–64. The associations between negative interference (either work-home or home-work) and sleep quality, self-rated health, and the use of sleeping pills/tranquillizers are analyzed by means of logistic regressions, compiling odds ratios (ORs) with 95% confidence intervals (CIs). The impact of adjustment for lack of unwinding on these associations is assessed. Results: Work-home interference is associated with suboptimal sleep quality and self-rated health for both women and men. The significance of this disappears among women after adjustment for lack of unwinding, regardless of work schedule. Among both sexes, home-work interference is associated with suboptimal sleep quality and self-rated health. When adjusting for lack of unwinding, the relationship to sleep quality disappears, but not the one to self-rated health, equally for women and men. Conclusion: Only among women, unwinding seems to buffer the association between work-home interference and health.     

Molecular refinement of the 1p36 deletion syndrome reveals size diversity and a preponderance of maternally derived deletions

The deletion of chromosome 1p36 is a newly recognized, relatively common contiguous gene deletion syndrome with a variable phenotype. The clinical features have recently been delineated and molecular analysis indicates that the prevalence of certain phenotypic features appears to correlate with deletion size. Phenotype/genotype comparisons have allowed the assignment of certain clinical features to specific deletion intervals, significantly narrowing the regions within which to search for candidate genes. We have extensively characterized the deletion regions in 30 cases using microsatellite markers and fluorescence in situ hybridization analyses. The map order of 28 microsatellite markers spanning the deletion region was obtained by a combination of genotypic analysis and physical mapping. The deletion region was divided into six intervals and breakpoints were found to cluster in mainly two regions. Molecular analysis of the deletions showed that two patients had complex re-arrangements; these cases shared their distal and proximal breakpoints in the two common breakpoint regions. Of the de novo deletions ( n = 28) in whichparental samples were available and the analysis was informative ( n = 27), there were significantly morematernally derived deletions ( n = 21) than paternally derived deletions ( n = 6) (chi1(2) = 8.35, P < 0.0001). Phenotype/genotype correlations and refinements of critical regions in our naturally occurring deletion panel have delineated specific areas in which to focus the search for the causative genes for the features of this syndrome.      

Circulating eosinophil/basophil progenitors and nasal mucosal cytokines in seasonal allergic rhinitis

Accumulation of eosinophils in the airways is characteristic of allergic rhinitis and asthma. The tissue eosinophilia may involve both recruitment of mature eosinophils and proliferation of their progenitors. This study examines mature eosinophils (nasal and circulating), their circulating progenitors, and a potential role of granulocyte-macrophage colony-stimulating factor (GM-CSF) in stimulating these progenitors. Twelve subjects with a history of seasonal allergic rhinitis and positive skin prick test for birch pollen were studied during four periods: shortly before, in the early and intense phase, at the end, and well after the Swedish birch-pollen season. Nasal mucosal and circulating eosinophils were examined in both nasal brushings and peripheral blood samples. Eosinophil/basophil progenitors were determined by counting colony-forming units in nonadherent mononuclear blood-cell cultures in methylcellulose at 14 days. The nasal mucosal cytokines GM-CSF, interleukin (IL)-1beta, IL-3, IL-5, IL-6, IL-8, and RANTES were analyzed (ELISA) in nasal lavage (NAL) fluids. All patients developed severe symptoms of rhinitis at the height of the season, with increased numbers of eosinophils in the nasal mucosa (P<0.05) and in the circulation (P<0.05). At this time point, the number of circulating progenitors (P<0.05) and the NAL fluid level of GM-CSF (P<0.05) were also increased. In contrast, there was no change in the NAL fluid levels of IL-1beta, IL-3, IL-6, or IL-8. Neither IL-5 nor RANTES could be detected in any of the NAL fluids. At the end of or after the season, there was no increase in nasal eosinophils or circulating eosinophils or progenitors (P>0.05). Ex vivo addition of GM-CSF (10-100 U) increased the number of blood progenitors grown before (P<0.01) and after (P<0.05) the season, compared with during the season. The in vitro GM-CSF responsiveness of progenitors may be related to whether or not these already have been stimulated endogenously by GM-CSF. Taken together, our data thus suggest that GM-CSF may play a role in vivo to increase production of eosinophilic progenitors in allergic airway disease.