Effectiveness of seasonal influenza vaccine in preventing laboratory-confirmed influenza in primary care in the United Kingdom: 2014/15 end of season results

The 2014/15 influenza season in the United Kingdom (UK) was characterised by circulation of predominantly antigenically and genetically drifted influenza A(H3N2) and B viruses. A universal paediatric influenza vaccination programme using a quadrivalent live attenuated influenza vaccine (LAIV) has recently been introduced in the UK. This study aims to measure the end-of-season influenza vaccine effectiveness (VE), including for LAIV, using the test negative case–control design. The overall adjusted VE against all influenza was 34.3% (95% confidence interval (CI) 17.8 to 47.5); for A(H3N2) 29.3% (95% CI: 8.6 to 45.3) and for B 46.3% (95% CI: 13.9 to 66.5). For those aged under 18 years, influenza A(H3N2) LAIV VE was 35% (95% CI: −29.9 to 67.5), whereas for influenza B the LAIV VE was 100% (95% CI:17.0 to 100.0). Although the VE against influenza A(H3N2) infection was low, there was still evidence of significant protection, together with moderate, significant protection against drifted circulating influenza B viruses. LAIV provided non-significant positive protection against influenza A, with significant protection against B. Further work to assess the population impact of the vaccine programme across the UK is underway.

Molecular diagnosis of haemophilia A at Centro Hospitalar de Coimbra in Portugal: study of 103 families--15 new mutations

Haemophilia A (HA), the most commonly inherited bleeding disorder, has well known phenotype heterogeneity, influenced by the type of mutation, modulating factors and development of inhibitors. Nowadays, new technologies in association with bioinformatics tools allow a better genotype/phenotype correlation. With the main objective of identifying familial carrier women and to offer prenatal diagnosis, 141 HA patients belonging to 103 families, followed or referred to the Haemophilia Centre of CHC, E.P.E., were studied. Molecular diagnosis strategy was based on HA severity: IVS22 and IVS1 inversions, direct sequencing and MLPA technique. New missense and splicing mutations were further analyzed using molecular modelling. Genotype/phenotype correlation was assessed taking into account the known modulating factors. During this study, mutations were detected in 102/103 families, carrier status was determined in 83 women and 14 prenatal diagnoses were performed. In a total of 46 different mutations identified, 15 have not been reported previously by the HAMSTeRS and HGMD. Genotype/phenotype correlation revealed two cases with a clinical picture less severe than expected by the type of mutation identified. Six patients developed inhibitors: five severe (IVS22, IVS1, large deletion) and one mild (p. Gln2265Lys). The adopted strategy allowed the identification of 99% of the molecular alterations underlying the HA phenotype (98% detection rate for severe and 100% for moderate and mild). Evaluation of genotype-phenotype correlation was complemented with structural protein modelling of newly identified missense mutations, contributing to better understanding of the disease-causing mechanisms and to deepening knowledge on protein structure-function.

Detection of the steroidogenic acute regulatory protein, StAR, in human liver cells

Overexpressing StAR (a mitochondrial cholesterol transporter) increases (>5-fold) the rate of 27-hydroxylation of cholesterol and the rates of bile acid synthesis in primary rat hepatocytes; suggesting that the transport of cholesterol into mitochondria is rate-limiting for bile acid biosynthesis via the CYP27A1 initiated 'acidic' pathway. Our objective was to determine the level of StAR expression in human liver and whether changes in StAR would correlate with changes in CYP27A1 activity/bile acid synthesis rates in human liver tissues. StAR mRNA and protein were detected in primary human hepatocytes and HepG2 cells by RT-PCR/Northern analysis and by Western analysis, respectively. In immunocompetition assays, liver StAR was competed away with the addition of purified human adrenal StAR. Overexpressing CYP27A1 in both cell types led to >2-fold increases in liver StAR concentration. StAR protein levels also increased approximately 2-fold with the addition of 27-hydroxycholesterol to HepG2 cell culture medium. Overexpressing StAR increased the rates of 27-hydroxylation of cholesterol/bile acid synthesis in both cell lines and increased intracellular levels of 27-hydroxycholesterol. In conclusion, human liver cells contain regulable StAR protein whose level of expression appears capable of regulating cellular cholesterol homeostasis, representing a potential therapeutic target in the management of hyperlipidemia.

A novel crosslinking reagent and its application for the detection and isolation of heparin-binding protein(s) on the platelet surface

A new hetero-bifunctional photo crosslinking reagent, 2-(4-azidoanilyl)-4-(4-azabicyclo-[2,2, 2]hexylammonio)-6-morpholino-1,3,5-triazine chloride, was designed to detect and isolate heparin-binding protein(s) that may act as heparin-receptor(s) on the platelet surface. In a preliminary study using ethanol as a model substrate, the reagent was shown to react with the alcoholic hydroxy group under mild conditions and its crosslinking photoreactivity was high. The reagent effectively formed similar covalent bonds with heparin, while preserving its anticoagulant anti-Xa activity. [3H]Heparin labeled with this reagent crosslinked to antithrombin III very specifically but not to ovalbumin, as analyzed by the Bio-imaging Analyzer System (BAS, Fuji Photo Film, Tokyo). Affinity crosslinking of [3H]heparin was then used to detect heparin-binding proteins on the surface of intact platelets. Several discrete protein bands were detected by the BAS-imaging of SDS-PAGE.

Polypectomy and endometrial resection in postmenopausal patients

STUDY OBJECTIVE

To evaluate the therapeutic efficacy of polypectomy associated with endometrial resection for the treatment of polyps in postmenopausal women.

DESIGN

Prospective study (Canadian Task Force classification II-2).

SETTING

Private urban hospital with facilities for endoscopic surgery.

PATIENTS

Sixty-six women with endometrial polyps.

INTERVENTIONS

Sixty-four of the 66 patients underwent polypectomy followed by endometrial resection. One patient had hysterectomy because endometrial biopsy showed serous papillary carcinoma.

MEASUREMENTS AND MAIN RESULTS

No major complications were associated with the procedure. Histopathology showed hyperplasia in most polyps. One patient had a papillary uterine carcinoma in the polyp that was not detected by preoperative endometrial biopsy. The women were followed with transvaginal sonography for 1 year after surgery.

CONCLUSION

Polypectomy followed by endometrial resection is a very low-risk procedure for postmenopausal patients. There was no recurrence after the first year in women who completed follow-up.

Prevention of arterial thrombosis using a novel heparin with enhanced antiplatelet activity and reduced anticoagulant activity

PURPOSE

Thrombosis after arterial injury is often initiated by von Willebrand factor (vWF)-dependent platelet accumulation. A promising antithrombotic strategy is the interruption of platelet/vWF interactions. Previously, we demonstrated how chemical and affinity modification can enhance heparin's anti-vWF activity while reducing conventional anticoagulation. Here, we investigated whether a modified heparin can block platelet-dominated arterial thrombosis.

METHODS

Standard heparin was oxidized with periodate, refined to have high vWF affinity and inhibitory potency, and tested in a guinea pig model of platelet-dependent arterial thrombosis. In this model, a controlled mechanical arterial injury yields cyclic flow variations (CFVs) caused by recurrent accumulation of platelet thrombi.

RESULTS

All six control animals developed CFVs (mean, 10.4 +/- 2.6 CFVs), and six of seven animals treated with standard heparin also developed CFVs (mean, 7.6 +/- 4.6). Only one of six animals treated with the anti-vWF heparin and one of six treated with AJvW-2 (an anti-vWF antibody) developed CFVs (mean, 2.0 +/- 4.9 and 0.5 +/- 1.2, respectively). Thus both the modified heparin and AJvW-2 were more effective than standard heparin (p < 0.03). Bleeding times and platelet counts were unaffected. A modified activated partial thromboplastin time was less prolonged by the modified high-affinity heparin (91 +/- 17) seconds) than by standard heparin (144 +/- 30 seconds; p < 0.01).

CONCLUSIONS

The modified heparin with high vWF affinity was a more effective arterial antithrombotic agent, with fewer conventional anticoagulant effects than standard heparin. Interruption of the vWF/platelet interaction is a promising antithrombotic strategy that may be met by novel heparin-based antithrombotic drugs.

Structural aspects of heparin responsible for interactions with von Willebrand factor

Unfractionated heparin (UFH) binds von Willebrand factor (vWF) and inhibits the vWF-platelet GP Ib interaction. For vWF, a heparin-binding domain has been identified, but for heparin, the structures that confer such activity are unknown. To investigate this, UFH was depolymerized by methods that yield structurally distinct fragments. The glycosaminoglycans (GAGs) produced were separated into five groups of homogeneous molecular weight (MW). Anti-Xa activity, vWF binding affinity, and vWF-dependent platelet agglutination were measured. Periodate oxidation but not heparinase digestion destroyed anti-Xa activity. At all MWs, periodate conferred greater vWF binding affinity and greater ability to inhibit platelet agglutination than heparinase. As an example, at MW 6100, the binding IC50 was 100+/-19 micromol/L for a periodate-derived GAG and 527+/-70 micromol/L for a heparinase-derived GAG. At the same MW, the agglutination IC50 was 17+/-5 micromol/L for periodate and 135+/-18 micromol/L for heparinase. This suggests that the disaccharide GlcNS[6S]-IdoA2S, destroyed by heparinase but not periodate, is crucial to heparin-vWF interactions. An MW dependency was also noted, with a minimum dodecasaccharide required for activity inhibition. To further investigate the heparin/vWF interaction, affinity fractionation of heparins was performed with an immobilized peptide derived from a heparin-binding domain of vWF. Disaccharide analysis of high-affinity heparins revealed an increased ratio of IdoA2S-GlcN[S/Ac]6S to IdoA2S-GlcN[S/Ac]. Affinity fractionation of oligosaccharides (MW 3500) diminished the relative content of all disaccharides except IdoA2S-GlcNS6S, which was increased. These data suggest that the disaccharide structures IdoA2S-GlcNS6S and GlcNS6S-IdoA2S are crucial to heparin/vWF interactions. Understanding the structural aspects that confer such activity may be useful in designing heparin-based antithrombotic drugs.

Administration of medroxyprogesterone acetate after endomyometrial resection

STUDY OBJECTIVE

To assess the efficacy of endometrial resection for treatment of menorrhagia in women to whom no preoperative agent was given to prepare the endometrium.

DESIGN

Retrospective analysis of patients' records for all endometrial resections in which medroxyprogesterone acetate was used postoperatively.

SETTING

Hospital day surgery unit.

PATIENTS

Seventy patients with menorrhagia.

INTERVENTIONS

The women underwent transvaginal sonography, followed by hysteroscopy and endometrial biopsy. The endometrium was removed using the 27F resectoscope followed by coagulation with the rollerball. Medroxy-progesterone acetate was prescribed for 2 months after surgery.

MEASUREMENTS AND MAIN RESULTS

All women achieved a reduction in menstrual flow and 50% reported amenorrhea after endometrial resection. In only two was hysterectomy necessary due to recurrence of menorrhagia.

CONCLUSION

Preoperative endometrial preparation was unnecessary when endometrial resection was carried out for treatment of menorrhagia. However, the patients received medroxyprogesterone acetate postoperatively.

Hysteroscopy and transvaginal sonography in menopausal women receiving hormone replacement therapy

STUDY OBJECTIVE

To evaluate the endometrial cavity of menopausal women with irregular bleeding while receiving hormone replacement therapy.

DESIGN

Comparative evaluation of hysteroscopic and biopsy findings.

SETTING

A center for reproductive studies.

PATIENTS

Forty-one patients receiving different regimens of hormone replacement therapy.

INTERVENTIONS

Hysteroscopy, endometrial biopsy, and transvaginal sonography were performed in all 41 women. In 10 patients, endometrial polyps were removed with the resectoscope.

MEASUREMENTS AND MAIN RESULTS

Irregular bleeding during hormone replacement therapy was associated with atrophic endometrium whenever transvaginal sonography showed endometrial thickness to be less than 4 mm. In patients who developed increased endometrial thickness after hormone replacement therapy, hysteroscopy revealed the presence of endometrial polyps in the uterine cavity. Histopathologic examination of excised polyps revealed cystic or adenomatous hyperplasia confined to these lesions.

CONCLUSIONS

Endometrial polyps can appear in menopausal women receiving hormone replacement therapy despite the presence of progestins to oppose the action of estrogens.

Heparins designed to specifically inhibit platelet interactions with von Willebrand factor

BACKGROUND

Platelet interactions with the injured vessel wall may contribute significantly to the early and late failures of many cardiovascular interventions; the adhesive protein von Willebrand factor (vWF) is thought to play an important role. Previously, we demonstrated that heparin interfered with platelet/vWF hemostatic mechanisms by binding to vWF within the proteins's domain responsible for binding the platelet vWF receptor, glycoprotein Ib. The purpose of the present study was to develop and refine heparins with greater potency to inhibit platelet/vWF interactions.

METHODS AND RESULTS

Immobilized synthetic peptides based on a known heparin-binding domain of vWF were used to yield novel fractions of standard heparin that demonstrated a sevenfold increase in their ability to inhibit vWF-dependent platelet agglutination and vWF/platelet binding. The high vWF affinity heparin showed enhanced anti-factor Xa activity but comparable activated partial thromboplastin time activity. Chemical modification of a standard heparin by periodate oxidation and borohydride reduction enhanced its ability to inhibit platelet/vWF interactions by threefold, while eliminating more than 90% of its activated partial thromboplastin time and anti-factor Xa activity. Affinity chromatography of the chemically modified heparin yielded a heparin with an eightfold higher inhibitory potency than the original heparin.

CONCLUSIONS

Subspecies of heparin can be developed with significantly enhanced potency to inhibit vWF/platelet interactions. The vWF-inhibiting property of heparin can be dissociated from its antithrombin-binding activity. Based on a growing understanding of heparin/vWF interactions, combinations of affinity separations and chemical modifications could be designed to yield heparins uniquely suitable for prevention of arterial thrombosis.