Effect of body surface area and gender on wall thickness thresholds in hypertrophic cardiomyopathy.

BACKGROUND: Family screening for hypertrophic cardiomyopathy (HCM) is based on genetic testing and clinical evaluation (maximal left ventricular wall thickness (MWT) ≥15 mm, or ≥13 mm in first-degree relatives of HCM patients). The aim of this study was to assess the effect of gender and body size on diagnosis of HCM and prediction of clinical outcome. METHODS: This study includes 199 genotype-positive subjects (age 44 ± 15 years, 50% men) referred for cardiac screening. Gender-specific reference values for MWT indexed by body surface area (BSA), height and weight were derived from 147 healthy controls. Predictive accuracy of each method for HCM-related events was assessed by comparing areas under the receiver operating characteristic curves (AUC). RESULTS: Men had a higher absolute, but similar BSA- and weight-indexed MWT compared with women (14.0 ± 3.9 mm vs 11.5 ± 3.8 mm, p < 0.05; 6.8 ± 2.1 mm/m2 vs 6.6 ± 2.4 mm/m2; 0.17 ± 0.06 mm/kg vs 0.17 ± 0.06 mm/kg, both p > 0.05). Applying BSA- and weight-indexed cut-off values decreased HCM diagnoses in the study group (48% vs 42%; 48% vs 39%, both p < 0.05), reclassified subjects in the largest, lightest and heaviest tertiles (≥2.03 m2: 58% vs 45%; ≤70 kg: 37% vs 46%; ≥85 kg: 53% vs 25%, all p < 0.05) and improved predictive accuracy (AUC 0.76 [95% CI 0.69-0.82] vs 0.78 [0.72-0.85]; and vs 0.80 [0.74-0.87]; both p < 0.05). CONCLUSIONS: In genotype-positive subjects referred for family screening, differences in MWT across gender are mitigated after indexation by BSA or weight. Indexation decreases the prevalence of HCM, particularly in larger men, and improves the predictive accuracy for HCM-related events.

Joint health scores in a haemophilia A cohort from Pakistan with minimal or no access to factor VIII concentrate: correlation with thrombin generation and underlying mutation.

Haemophilia A is associated with recurrent joint bleeding which leads to synovitis and debilitating arthropathy. Coagulation factor VIII level is an important determinant of bleed number and development of arthropathy . The aim of this study was to compare the haemophilia joint health score (HJHS) and Gilbert score with severity, age, thrombin generation (TG) and underlying mutation in a haemophilia A cohort which had minimal access to haemostatic replacement therapy. Ninety-two haemophilia A individuals were recruited from Pakistan. Age, age at first bleed, target joints, haemophilic arthropathy joints, HJHS and Gilbert score were recorded. A strong correlation was found between HJHS and Gilbert score (r = 0.98), both were significantly higher in severe (n = 59) compared with non-severe (n = 29) individuals before the age of 12 years (P ≤ 0.01) but not thereafter. When individuals were divided according to developmental age (<12 years, 12-16 years and >16 years), both HJHS and Gilbert score were significantly lower in the youngest group (P ≤ 0.001), there was no difference between 12-16 years and >16 years. In severe individuals there was no correlation between in vitro TG and joint score, whereas in non-severe individuals there was a weak negative correlation. In the severe group, no significant difference was observed for either joint score according to the underlying mutation type (inversion, missense, nonsense, frameshift). In this cohort of haemophilia A individuals with minimal access to haemostatic treatment, haemophilic arthropathy correlated with severity and age; among severe individuals, joint health scores did not relate to either the underlying mutation or in vitro TG.

Characterization of F8 defects in haemophilia A in Pakistan: investigation of correlation between mutation type and the in vitro thrombin generation assay.

Hereditary haemophilia A is an X-linked bleeding disorder caused by mutations in the coagulation factor VIII gene (FVIII abbreviates protein, gene symbol F8). The mutation spectrum has been reported in various populations but not in Pakistan. The aims of this study were to (i) characterize F8 mutations in a large haemophilia A cohort from Pakistan and to (ii) investigate whether in vitro thrombin generation (TG) differs according to mutation type (null compared with missense) in severe haemophilia A. One hundred individuals diagnosed with haemophilia A and 100 healthy controls were recruited in Pakistan. Phenotypic measurements were re-evaluated in Cardiff; the essential regions of F8 were screened for the causative defect. A diagnosis of haemophilia A was confirmed for 92 individuals, 7 were found to have haemophilia B and 1 did not have haemophilia. The F8 defects were characterized for 80 of the 92 haemophilia A individuals and comprised point mutations, inversions (intron 22 and intron 1) and frameshifts. Point mutations (41%) were the most frequent, followed by the intron 22 inversion (20%). Thirty novel variants were identified. Comparison of in vitro TG parameters [velocity index (VI) and peak] was made between severe individuals who had a null mutation (no FVIII) and those with a missense change (dysfunctional FVIII), no significant difference was observed. The spectrum of F8 defects in Pakistan is heterogenous; VI and peak in severe haemophilia A are not influenced by whether the underlying mutation gives rise to dysfunctional FVIII or no coagulation factor at all.

von Willebrand factor: evidence for variable clearance in vivo according to Y/C1584 phenotype and ABO blood group.

BACKGROUND: The plasma von Willebrand factor (VWF) level (VWF:Ag) is known to correlate with the VWF Y/C1584 variation and with ABO blood group. The ratio of the VWF propeptide (VWFpp) to VWF:Ag and the ratio of coagulation factor VIII (FVIII:C) to VWF:Ag have previously been used as indicators of VWF clearance and/or secretion. OBJECTIVES AND METHODS: To investigate the mechanism underlying the relationship between VWF phenotype and VWF:Ag, the VWFpp/VWF:Ag ratio and FVIII:C/VWF:Ag ratio were determined for plasmas of phenotype Y/C1584, Y/Y1584, blood group O and blood group A (n = 50 for each set). The blood group O plasmas comprised two sets of 25 with low and high mean VWF levels (Low-O and High-O), respectively; similarly for group A (Low-A and High-A). RESULTS AND CONCLUSIONS: The VWFpp/VWF:Ag ratio was greater than 1 (unity) for Y/C1584 plasmas and significantly higher than for Y/Y1584 plasmas; however, the FVIII:C/VWF:Ag ratio was near unity for both and was not significantly different. These results are consistent with increased clearance for Y/C1584 VWF. Similarly, the VWFpp/VWF:Ag ratio and FVIII:C/VWF:Ag ratio in combination were consistent with increased VWF clearance in blood group O compared with blood group A, and in Low-O and Low-A, respectively, compared with High-O and High-A. The data indicate that in vivo C1584 and blood group O are associated with increased VWF clearance, and that clearance contributes to differing VWF level within a given blood group.

The tc genes of Photorhabdus: a growing family.

The toxin complex (tc) genes of Photorhabdus encode insecticidal, high molecular weight Tc toxins. These toxins have been suggested as useful alternatives to those derived from Bacillus thuringiensis for expression in insect-resistant transgenic plants. Although Photorhabdus luminescens is symbiotic with nematodes that kill insects, tc genes have recently been described from other insect-associated bacteria such as Serratia entomophila, an insect pathogen, and Yersinia pestis, the causative agent of bubonic plague, which has a flea vector. Here, recent advances in our understanding of the tc gene family are reviewed in view of their potential development as insect-control agents.

Echocardiographic examination of women previously treated with fenfluramine: long-term follow-up of a randomized, double-blind, placebo-controlled trial.

BACKGROUND: Fenfluramine hydrochloride was withdrawn from the market in September 1997 after reports of heart valve abnormalities in patients who used it. The prevalence of echocardiographic abnormalities and the clinical cardiovascular status of patients who received fenfluramine monotherapy remains uncertain. METHODS: A long-term, follow-up evaluation was undertaken in subjects who were randomly assigned to receive either fenfluramine hydrochloride (60 mg daily) or placebo as part of a double-blind smoking cessation therapy study. Cardiovascular status was evaluated by echocardiography, medical history, and physical examination. RESULTS: From the group of 720 smokers who had originally participated in the smoking cessation therapy trial, 619 women were enrolled; data from 530 (276 in the fenfluramine group and 254 in the placebo group) were evaluable. No statistically significant differences were identified in the prevalence of aortic or mitral regurgitation by Food and Drug Administration criteria or by grade, aortic or mitral valve leaflet mobility restriction or thickening, elevated pulmonary artery systolic pressure, or abnormal left ventricular ejection fraction. No significant differences were demonstrated in cardiovascular status by physical examination, and no serious cardiac events were noted among fenfluramine-treated subjects. CONCLUSION: There was no evidence of drug-related heart disease up to 4.9 years after anorexigen therapy in subjects who were randomly assigned to receive fenfluramine at the recommended dose for up to 3 months.

Effects of dietary fat intervention on mental health in women.

Several studies have identified potential detrimental sequelae of cholesterol and fat-lowering interventions in randomized trial. Little research has been published to document changes in mental health in women as a result of fat and cholesterol lowering interventions to prevent chronic disease. This paper examines the relationships among changes in dietary fat consumption and mental health in the Women's Health Trial, a randomized, controlled trial to determine whether lowering fat consumption to 20% of daily calories could reduce the incidence of breast cancer in women ages 45-69 years. Assessments were made at baseline and at the 12-month follow-up of several aspects of quality of life, including negative and positive affect and past, present, and future perceptions of health. Mental health variables were measured by the Mental Health Inventory, a standardized scale used in the Medical Outcomes study. Dietary intake was assessed for all subjects with the use of semiquantitative food frequency questionnaires. The change in mental health values (follow-up minus baseline) was significantly different between intervention and control groups for three of the four psychological variables: (a) anxiety; (b) depression; and (c) vigor. In all three cases, the direction of the change for intervention women was positive. Neither randomization assignment nor percent of calories from fat at the follow-up visit were significant predictors of mental health at the 1-year follow-up. Cholesterol changes were not related to levels of mental health variables in a sample of the women. These data indicate that lowering fat in the diets of healthy women does not produce overall lowering of any mental health variables.(ABSTRACT TRUNCATED AT 250 WORDS)

Predictors of participation in genetic research in a primary care physician network.

This study evaluated the process of recruiting women from a primary care physician network into a study of genetic counseling for breast cancer. It also investigated predictors of women's interest in participating in genetic counseling research. Women were recruited in three stages: (a) via an initial contact letter; (b) a telephone screening survey; and (c) a mailed baseline questionnaire. We performed a logistic regression with participation as the outcome. We sent 4690 initial contact letters and conducted 2081 telephone surveys to recruit 340 participants. Number of relatives with cancer, higher interest in taking a genetic test for breast cancer, and lower degree of worry about cancer were strong predictors for women's participation. Recruitment data showed interest in a study on genetic counseling for breast cancer risk. However, interest decreased as study requirements increased. Participation in genetics-related studies is related to psychological differences that must be considered when generalizing findings.

Feasibility of using volunteer research staff to deliver and evaluate a low-fat dietary intervention: the American Cancer Society Breast Cancer Dietary Intervention Project.

This report presents the results of a study to examine the feasibility of using volunteers as research staff for a randomized trial of whether reduction in dietary fat intake could prevent or delay breast cancer recurrence. We examined whether volunteers could be trained to recruit study participants, deliver a complex and intensive dietary intervention, and monitor intervention effectiveness. Volunteers, who were mostly employed nurses and dietitians, screened 521 women, of whom 293 were eligible and 144 were randomized. Participants were postmenopausal women under age 75, who had recently been diagnosed with breast cancer and treated with either mastectomy or lumpectomy. At 1 year postrandomization, 77% of intervention and 75% of control participants remained active in the study. Intervention effects (change in intervention group minus change in control group) at 3, 6, and 12 months postrandomization were 5.9, 8.4, and 7.2% energy from fat and 1.7, 3.0, and 3.5 kg body weight (all P < 0.001). These results were similar to those from other studies that used paid, professional staff to deliver and monitor interventions. Results from this feasibility study suggest that volunteer-based health organizations can provide research opportunities for health practitioners and can conduct high-quality research at lower costs.

Attitudes and interest in genetic testing for breast and ovarian cancer susceptibility in diverse groups of women in western Washington.

OBJECTIVES: This paper examines the knowledge, opinions, and predictors of interest in genetic testing for breast cancer risk in a demographically diverse group of women in western Washington who participated in a randomized controlled trial (RCT) of breast cancer risk counseling methods. MATERIALS AND METHODS: Four groups of women were surveyed, all with some family history of breast cancer: (a) 307 white women; (b) 36 African-American women; (c) 87 lesbian/bisexual women; and (d) 113 Ashkenazi Jewish women. As part of the baseline questionnaire for the RCT, participants were asked about their familiarity with genetic testing for breast cancer risk, their interest in such testing and opinions of it, and actions they anticipated based on test results. RESULTS: Women in all four groups favored ready access to testing, believed the decision to be tested should be a personal choice, believed that genetic test results should stay confidential, and were not greatly concerned that this might not be possible. Women anticipated using such genetic test results to increase the frequency of various breast cancer screening methods (in all four groups, > 69% would increase mammogram frequency, > 85% would increase clinician exam, and > 92% would increase breast self exam). Women overwhelmingly rejected prophylactic surgery as a preventive measure (in all > 80% probably or definitely would not consider it). Significant predictors of interest in genetic testing for cancer risk included perceived risk, cancer worry, and beliefs about access to testing. CONCLUSIONS: These data will be of interest to health care providers, payers, public health professionals, legislators, and others as they consider issues associated with population testing for susceptibility to common diseases such as breast cancer.

An influence of ABO blood group on the rate of proteolysis of von Willebrand factor by ADAMTS13.

The susceptibility of von Willebrand factor (VWF) of blood group O, A, B and AB to proteolysis by the ADAMTS13 metalloprotease was investigated. Multimeric analysis indicated that the rate of VWF proteolysis differed between blood groups and was greater for group O VWF than for non-O VWF in the rank order O >/= B > A >/= AB. Measurement of the collagen binding activity of VWF of each blood group following proteolysis for a fixed time interval corroborated the results obtained on multimer analysis: the loss of collagen binding activity was greater for VWF of group O compared with non-O VWF, in the rank order O >/= B > A >/= AB. Ristocetin was found to increase the rate of VWF proteolysis approximately two-fold; the differential between blood groups was retained in the presence of ristocetin.

Increased clearance of von Willebrand factor antigen post-DDAVP in Type 1 von Willebrand disease: is it a potential pathogenic process?

The mechanism of von Willebrand factor (VWF) clearance is not fully understood. The factors that affect VWF clearance, and the normal in vivo mechanism of clearance, may be relevant to the pathogenesis of Type 1 von Willebrand disease (VWD), in which there is a partial deficiency of VWF. In order to investigate the clearance of VWF in Type 1 VWD, the current study assessed the half-life of VWF antigen (t(1/2) VWF:Ag) in Type 1 VWD patients and individuals with mild hemophilia A following the administration of 1-deamino-8-d-arginine vasopressin (DDAVP; desmopressin). To date 20 individuals have been assessed, 13 with Type 1 VWD and seven with mild hemophilia A. The median t(1/2) VWF:Ag in the Type 1 VWD and mild hemophilia A groups were 4.6 h and 9.5 h, respectively. The difference between the t(1/2) VWF:Ag for the two groups was significant, P < 0.02. Analysis of the data showed a correlation between the t(1/2) VWF:Ag and the baseline VWF:Ag level prior to administration of DDAVP: lower baseline VWF:Ag levels were associated with a shorter t(1/2) VWF:Ag. These data suggest that increased clearance of VWF may be the pathogenic mechanism in some cases of Type 1 VWD.

Factor V Leiden (G1691A), the prothrombin 3'-untranslated region variant (G20210A) and thermolabile methylenetetrahydrofolate reductase (C677T): a single genetic test genotypes all three loci--determination of frequencies in the S. Wales population of the UK.

Simultaneous genetic diagnosis of factor V (FV) Leiden (G1691A), the prothrombin variant (G20210A) and the thermolabile methylenetetrahydrofolate reductase (MTHFR) variant (C677T) has been achieved using multiplex heteroduplex analysis. All three loci are amplified in a single polymerase chain reaction (PCR) containing test DNA and three heteroduplex generators, respectively detecting the three nucleotide substitutions. After PCR, the products are analysed directly without further manipulation and the resulting heteroduplex profiles permit straightforward interpretation of the respective genotypes. The multiplex test has been used to assess the prevalence and allele frequency of each of the three nucleotide substitutions in 300 individuals (150 males and 150 females) from the local (S. Wales) population. A prevalence of 8% and an allele frequency of 0.040 +/- 0.015 (95% confidence interval) was obtained for FV Leiden; the prothrombin variant showed a prevalence of 1% and an allele frequency of 0.007 +/- 0.006 (95% confidence interval); the MTHFR mutation showed a prevalence of 60% and an allele frequency of 0.377 +/- 0.039 (95% confidence interval). This method is applicable to investigation of large cohorts of patients with arterial or venous thrombotic disease.

Female twins with severe Christmas disease (hemophilia B).

Hemophilia B is an X-linked bleeding disorder. We report on female twins, who were conspicious in prolonged bleeding after venipuncture as well as hematomas after intramuscular injections even in the first months of their life. Their father suffering from a severe hemophilia B deceased in 1992. Their mother, half-brother and grandmother from their father's side had no signs of bleeding disorders. Clotting analysis performed in both twins revealed a markedly prolonged partial thromboplastin time (> 100 s). The factor IX levels were below 2%. In order to detect mutations, a general screen using the polymerase chain reaction (PCR) followed by single strand conformation polymorphism (SSCP) analysis of the PCR products have been performed. PCR products have been cut into smaller fragments using restriction endonucleases (RE) for an in-depth SSCP screen. A general screen for gross abnormalities in the factor IX gene including deletions, insertions and rearrangements was performed by Southern blot analysis of RE-digests of genomic DNA using the factor IX cDNA as a hybridization probe. Furthermore, we screened for mutations in the CG dinucleotides comprising part of RE-recognition sequences (exon 1, 2, 3, 4, 5, and 8). By all methods applied herein, no mutations have been detected in these twins. On the basis of our results the hemophilia B of these twins might be explained by extreme non-random lyonization.

UHG-based mutation screening in type 2B von Willebrand's disease: detection of a candidate mutation Ser547Phe.

We have recently described a novel mutation screening technique for the diagnosis of type 2B von Willebrand's disease (vWD). Analysis involves the use of a synthetic universal heteroduplex generator (UHG). To test the validity of the technique, we have applied UHG screening to seven type 2B vWD patients of previously unknown genotype. Characteristic heteroduplex patterns for Arg543Trp and Val553Met mutations were found in three patients and one patient, respectively. A fifth patient gave a novel pattern and direct sequencing revealed a hitherto unreported candidate mutation (Ser547Phe) 8 bases downstream of an "identifier" deletion in the UHG molecule. The two remaining patients gave normal heteroduplex patterns; an Arg578Gln mutation was identified by PstI digestion in one individual and no mutation could be identified in the sequence covered by the UHG in the final patient. Using a combination of UHG technology and restriction analysis, over 85% of type 2B vWD patients can be rapidly diagnosed by genotype.

Type 2N von Willebrand disease: rapid genetic diagnosis of G2811A (R854Q), C2696T (R816W), T2701A (H817Q) and G2823T (C858F)--detection of a novel candidate type 2N mutation: C2810T (R854W).

The majority of patients with type 2N von Willebrand disease (VWD type 2N) have mutations in the region of the von Willebrand factor (VWF) gene encoding the factor VIII binding domain of VWF. Two mutations predominate among VWD type 2N patients: G2811A and C2696T, which respectively bring about the amino acid substitutions R854Q and R816W in VWF. Several other mutations have been found in VWD type 2N, including T2701A (H817Q) and G2823T (C858F). We have developed a genetic test which permits rapid screening for these four mutations in a single polymerase chain reaction (PCR). The test employs induced heteroduplex formation using two universal heteroduplex generators, one of which detects G2811A (R854Q) and G2823T (C858F), the other detects C2696T (R816W) and T2701A (H817Q). The allele frequency of the common G2811A (R854Q) mutation was investigated in the local (S. Wales) population by examination of 216 VWF genes (108 individuals) and was found to be 0.01. The heteroduplex-based test additionally detected a novel candidate type 2N mutation, C2810T (R854W) and a previously described polymorphism, G2805A (R852Q). The polymorphism showed allele frequencies of 0.92 (G nucleotide) and 0.08 (A nucleotide) in the population study.

Genetic diagnosis of factor V Leiden using heteroduplex technology.

A new genetic test has been developed for detection of the mutation known as factor V Leiden. The test employs heteroduplex technology and comprises a single PCR reaction followed immediately by PCR product analysis. It therefore represents the minimum practical route from blood/tissue sample to genetic result. A cohort of 100 patients with a history of thrombosis have been screened using both the new heteroduplex test and a previously described PCR-restriction endonuclease test. Results gave 100% correlation: normals 75 (75%), heterozygotes 24 (24%) and homozygotes 1 (1%). The heteroduplex test has been shown to give straightforward diagnosis in three different analytical systems: standard polyacrylamide gel electrophoresis (PAGE), mini-gel PAGE and capillary electrophoresis. The latter system is semiautomated, therefore rapid through-put of large sample numbers is now possible.

Effects of nicotine on body weight and food consumption in female rats.

Women often report that they smoke cigarettes to avoid weight gains and that they relapse after abstaining from tobacco because of weight gains. Men also report these concerns but to a lesser extent. This gender difference may reflect sociological and cultural pressures about physical appearance, or it may reflect sex differences in the effects of nicotine. The present research was designed to examine the effects of nicotine administration and cessation of nicotine on body weight, food consumption, and water consumption. Alzet miniosmotic pumps were implanted SC to administer saline or three different concentrations of nicotine to female Sprague-Dawley rats for 17 days. This paradigm has been used in previous studies of nicotine and body weight in male rats. Animals were used as subjects to avoid cultural factors and cognitive concerns about body weight. Nicotine administration decreased normal body weight gains and cessation of nicotine was accompanied by significant increases in body weight compared to controls. In contrast to previous studies of male rats, the nicotine-related changes in body weight were accompanied by changes in bland food and water consumption. These findings indicate that females are more sensitive than males to the effects of nicotine on body weight and feeding during and after drug administration.