The 4G/4G polymorphism of the hypofibrinolytic plasminogen activator inhibitor type 1 gene: an independent risk factor for serious pregnancy complications

The specific aim of the current study of 133 women with at least 1 pregnancy and measures of hypofibrinolytic and thrombophilic gene mutations was to determine retrospectively whether the mutations were associated with adverse pregnancy outcomes including prematurity, miscarriage, stillbirth, intrauterine growth retardation (IUGR), eclampsia, and abruptio placentae. Four gene mutations (factor V Leiden, methylenetetrahydrofolate reductase [MTHFR], prothrombin, and 4G/5G polymorphism of the plasminogen activator inhibitor type 1 [PAI-1] gene) were assessed by polymerase chain reaction (PCR). One hundred twenty-two women were genotyped for all 4 genes and divided into gene mutation (n = 68) and non-gene (n = 54) groups. The gene mutation group included those with at least 1 thrombophilic mutation (heterozygous for factor V Leiden, heterozygous for prothrombin, and homozygous for MTHFR), or hypofibrinolysis with homozygosity for the 4G polymorphism of the PAI-1 gene. The non-gene mutation group included those with no mutation for all 4 genes (wild-type normal) or who were wild-type normal for the prothrombin and factor V Leiden mutations and heterozygous for MTHFR and/or 4G/5G for the PAI-1 gene, neither heterozygosity associated with coagulation abnormalities. The 68 women with gene mutations, versus 54 in the non-gene mutation group, has more prematurity (10% v 4%, chi2 = 5.4, P = .021), more IUGR (3% v 0%, P = .035), and more total complications of pregnancy (37% v 21%, chi2 = 11.6, P = .001). The number of pregnancies (P = .0001) and 4G/4G polymorphism of the PAI-1 gene (P = .029) were positively associated with complications of pregnancy by stepwise logistic regression when the age, number of pregnancies, and all 4 gene mutations were the explanatory variables. Heritable hypofibrinolysis, mediated by 4G/4G homozygosity for the PAI-1 gene, is an independent significant, potentially reversible risk factor for pregnancy complications, probably acting through thrombotic induction of placental insufficiency.     

A sea urchin genome project: sequence scan, virtual map, and additional resources

Results of a first-stage Sea Urchin Genome Project are summarized here. The species chosen was Strongylocentrotus purpuratus, a research model of major importance in developmental and molecular biology. A virtual map of the genome was constructed by sequencing the ends of 76,020 bacterial artificial chromosome (BAC) recombinants (average length, 125 kb). The BAC-end sequence tag connectors (STCs) occur an average of 10 kb apart, and, together with restriction digest patterns recorded for the same BAC clones, they provide immediate access to contigs of several hundred kilobases surrounding any gene of interest. The STCs survey >5% of the genome and provide the estimate that this genome contains approximately 27,350 protein-coding genes. The frequency distribution and canonical sequences of all middle and highly repetitive sequence families in the genome were obtained from the STCs as well. The 500-kb Hox gene complex of this species is being sequenced in its entirety. In addition, arrayed cDNA libraries of >10(5) clones each were constructed from every major stage of embryogenesis, several individual cell types, and adult tissues and are available to the community. The accumulated STC data and an expanding expressed sequence tag database (at present including >12, 000 sequences) have been reported to GenBank and are accessible on public web sites.     

Prevalence of hepatitis C virus infection among injecting drug users in Glasgow 1990-1996: are current harm reduction strategies working?

OBJECTIVES: To determine the prevalence of HCV antibodies among injecting drug users and to gauge the effectiveness of needle/syringe exchange in preventing the transmission of HCV infection. METHODS: Between 1990-1994 and in 1996, annual cross-sectional surveys of injecting drug users in Glasgow were conducted. In order to ensure as representative a sample as possible, the 1949 respondents were recruited from both 'in-treatment' and 'out-of treatment' settings. Injectors were interviewed about their risk behaviours for blood-borne viruses and provided a saliva sample which was initially tested, anonymously, for HIV antibodies, and subsequently tested for hepatitis C infection. RESULTS: Among 1949 injectors, the prevalence of salivary antibodies, indicative of hepatitis C viraemia, was 61%(95%, confidence interval (CI) 59%-63%): the estimated prevalence of serum antibody positivity was 72%. Length of injecting, year of commencing drug injecting and the number of times in prison were predictive of antibody positivity. Thirty-one per cent of injectors who commenced their injecting after 1992, following the full establishment of needle/syringe exchange in the city, were salivary antibody positive, and the majority of their infections were acquired outside the prison setting. Respondents who began injecting after the introduction of needle/syringe exchange in the city were significantly less likely to test HCV antibody positive than those who commenced injecting prior to the advent of needle/syringe exchange, after adjusting for length of injecting career. CONCLUSION: The prevalence of HCV among injectors in Glasgow has decreased during the era of needle/syringe exchange. However, there is evidence to suggest that the incidence of infection remains high. Since the prevalence of hepatitis C viraemia among the city's injecting population is extremely high, ongoing transmission is inevitable unless more effective interventions are identified and implemented urgently.     

Using a driving simulator to identify older drivers at risk of traffic infringements

Objectives: To determine the internal consistency of assessment criteria measuring the simulated driving performance of older drivers and the criterion validity of the assessment protocol related to traffic infringements. Method: One hundred and twenty‐nine older drivers residing in metropolitan Perth volunteered to participate in the study. Using a driving simulator, specific driving tasks were devised to test the participants, whose performances were measured by ten assessment criteria. Logistic regression analysis was then undertaken to determine those criteria that may be related to the event of incurring at least one demerit point during the previous two years. Results: As expected, driving skill of older drivers was found to decline with age. The Cronbach alpha coefficient among the assessment criteria was 0.742. Forty six participants incurred at least one demerit point within the previous two years. Adjusting for age in the logistic regression, the functional abilities associated with traffic infringements were decision and judgement under pressure of time, confidence in driving with high speed and compliance to traffic regulation. Conclusions: For the present study sample, the identified assessment criteria measuring the simulated driving performance of older drivers were shown to be reliable, and their significant association with the event of incurring a demerit point further confirmed the criterion validity of using the laboratory‐based driving simulator to identify older drivers at risk of traffic infringements incurring demerit points.     

Osteoblast-derived cells express functional glucose-dependent insulinotropic peptide receptors

Glucose-dependent insulinotropic peptide (GIP) is a 42-amino acid peptide synthesized and secreted from endocrine cells in the small intestine. The role of GIP in coupling nutrient intake and insulin secretion, the incretin effect, is well known. We report that GIP receptor messenger RNA and protein are present in normal bone and osteoblast-like cell lines, and that high affinity receptors for GIP can be demonstrated by [125I]GIP binding studies. When applied to osteoblast-like cells (SaOS2), GIP stimulated increases in cellular cAMP content and intracellular calcium, with both responses being dose dependent. Moreover, administration of GIP results in elevated expression of collagen type I messenger RNA as well as an increase in alkaline phosphatase activity. Both of these effects reflect anabolic actions of presumptive osteoblasts. These results provide the first evidence that GIP receptors are present in bone and osteoblast-like cells and that GIP modulates the function of these cells.     

Idarubicin and cyclophosphamide--an active oral chemotherapy regimen for advanced breast cancer

Between October 1993 and September 1994, 33 women with metastatic breast cancer aged between 29 and 74 years with a median age of 58 were entered into a study of oral chemotherapy from three UK centres. Patients by definition had metastatic disease and were fit and well with performance status 0 or 1 in 23 cases, 2 in seven cases and 3 in two cases (one missing). Five patients had received prior adjuvant CMF chemotherapy, nine first line non-anthracycline containing chemotherapy for relapse, eight patients second line non-anthracycline containing chemotherapy and all patients had had hormone therapy either as adjuvant or for relapsed disease. Adjuvant radiotherapy had been given to 17 and palliative radiotherapy to 12 patients. In nine patients there was one site of disease at start of therapy, in 10 two sites, in 11 three sites and in three patients four or more sites. The regimen comprised oral idarubicin 15 mg/m2 on day 1, 10 mg/m2 on days 2 and 3 and oral cyclophosphamide 250 mg/m2 (maximum 400 mg) on days 1, 2 and 3. Treatment was continued until disease progression or toxicity. RESULTS: Overall 25% of 32 evaluable patients responded objectively including one complete response; 50% of patients had stable disease and 25% of patients progression. Among patients who had had no prior chemotherapy the objective response rate was 37.5%; 45% of patients had symptomatic improvement. The most common severe toxicity was granulocytopenia WHO grade 3 or more in 69.7% of patients. Thrombocytopenia grade 3 or 4 was seen in four patients. Six patients had documented infections and all but four patients had alopecia. All patients complained of mild or moderate fatigue. Nausea and vomiting occurred in 75% of patients but only four individuals had grade 3 toxicity. Two patients stopped therapy after myocardial infarction and one after impaired cardiac function was noted. The median time to progression was 2.7 months (1-11.5 months) and median survival time 8.8 months (1-13+ months). CONCLUSION: The combination chemotherapy is active in heavily treated patients with manageable toxicity but there are problems in heavily pre-treated patients. There was good compliance in taking medication and at the doses chosen the drugs appear to be suitable for younger fitter patients.     

Large-scale conformational sampling of proteins using temperature-accelerated molecular dynamics

We show how to apply the method of temperature-accelerated molecular dynamics (TAMD) in collective variables [Maragliano L, Vanden-Eijnden E (2006) Chem Phys Lett 426:168–175] to sample the conformational space of multidomain proteins in all-atom, explicitly solvated molecular dynamics simulations. The method allows the system to hyperthermally explore the free-energy surface in a set of collective variables computed at the physical temperature. As collective variables, we pick Cartesian coordinates of centers of contiguous subdomains. The method is applied to the GroEL subunit, a 55-kDa, three-domain protein, and HIV-1 gp120. For GroEL, the method induces in about 40 ns conformational changes that recapitulate the t → r^′′ transition and are not observed in unaccelerated molecular dynamics: The apical domain is displaced by 30 Å, with a twist of 90° relative to the equatorial domain, and the root-mean-squared deviation relative to the r^′′ conformer is reduced from 13 to 5 Å, representing fairly high predictive capability. For gp120, the method predicts both counterrotation of inner and outer domains and disruption of the so-called bridging sheet. In particular, TAMD on gp120 initially in the CD4-bound conformation visits conformations that deviate by 3.6 Å from the gp120 conformer in complex with antibody F105, again reflecting good predictive capability. TAMD generates plausible all-atom models of the so-far structurally uncharacterized unliganded conformation of HIV-1 gp120, which may prove useful in the development of inhibitors and immunogens. The fictitious temperature employed also gives a rough estimate of 10 kcal/mol for the free-energy barrier between conformers in both cases.