A Six Year Prospective Study of Fibrinogen and Other Risk Factors Associated with Mortality in Stable Claudicants

A total of 333 patients with stable intermittent claudication at recruitment were followed up for 6 years to determine risk factors associated with subsequent mortality. Cardiovascular diseases were the underlying cause of death in 78% of the 114 patients who died. The strongest independent predictor of death during the follow-up period was the plasma fibrinogen level, an increase of 1 g/l being associated with a nearly two-fold increase in the probability of death within the next 6 years. Age, low ankle/brachial pressure index and a past history of myocardial infarction also increased the probability of death during the study period. The plasma fibrinogen level is a valuable index of those patients with stable intermittent claudication at high risk of early mortality. The results also provide further evidence for the involvement of fibrinogen in the pathogenesis of arterial disease.

Gastrointestinal side effects in chronic opioid users: results from a population-based survey

BACKGROUND

Gastrointestinal side effects are commonly associated with opioid treatment for pain.

AIM

To understand gastrointestinal side effects associated with opioid treatment.

METHODS

This study was a population-based survey of adults in the US who use opioids to manage pain unrelated to cancer. Participants were recruited from an existing Web-enabled panel and a supplemental panel of individuals who previously indicated an interest in participating in Web-based surveys.

RESULTS

Overall, 2055 individuals participated in the main phase of the survey. Fifty-seven per cent of participants reported having had constipation that they associated with opioid treatment, and 49% reported constipation in the previous 4 weeks. Thirty-six per cent of participants reported new or worsening constipation in the previous 4 weeks. Thirty-three per cent of participants reported constipation as their most bothersome symptom associated with opioid treatment, 13% reported nausea, 11% abdominal pain and 10% gas. Seventy-three per cent of the participants who reported any GI symptoms did not change the dosage level or frequency of use of opioids because of adverse events, which may be explained by the fact that 72% of participants used over-the-counter laxatives and 12% a prescription laxative.

CONCLUSION

Constipation is a frequent and significant event occurring with opioid use.

Venous thromboembolism in patients with brain tumors

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Venous Thromboembolism (VTE) is common in patients undergoing treatment for brain tumors. American College of Chest Physicians (ACCP) 2004 consensus conference recommends routine use of intermittent pneumatic compression devices (IPC), unfractionated heparin (UH) or low molecular weight heparin (LMWH) for VTE prophylaxis in these patients. There, however, continues to be a reluctance on using pharmacologic VTE prophylaxis in these patients. The goal of our study was to determine the incidence of VTE in patients with brain tumors treated at a community hospital and the frequency of use of thromboprophylaxis in these patients. Both electronic and paper charts of all patients treated for brain tumors between 1997 and 2003 were reviewed. Follow up data was obtained by contacting physicians caring for these patients. Forty two patients were identified (Anaplastic astrocytoma 10; Glioblastoma multiforme 16; Meningioma 15; oligodendroglioma 1). Twelve patients were treated with various adjuvant chemotherapy regimens. Only 16 patients (38%) received any form of VTE prophylaxis. UH (12) or LMWH (2) were used with or without IPCs or graduated compression stockings. There were eight episodes of symptomatic VTE among 42 patients (19%). These include 6 episodes of deep vein thrombosis (DVT) and two cases of superficial vein thrombosis. Three patients with DVT also had symptomatic pulmonary embolus (PE). All episodes VTE were seen in patients with malignant gliomas yielding a 29% incidence of VTE in patients with malignant gliomas. None of the 15 patients with meningioma had symptomatic VTE. All but one episode of VTE were associated with administration of systemic chemotherapy. Half of these episodes occured more than six weeks after surgical debulking. We conclude that incidence of VTE with malignant brain tumors is high (29%) and the administration of chemotherpy increases this risk. There continues to be underutilization of VTE prophylaxis in these patients at very high risk of VTE. Efforts should be directed at improving the understanding of type and duration of appropiate VTE prophylaxis in patients with brain tumors.

No significant financial relationships to disclose.

Development of educational image databases and e-books for medical physics training

Medical physics education and training requires the use of extensive imaging material and specific explanations. These requirements provide an excellent background for application of e-Learning. The EU projects Consortia EMERALD and EMIT developed five volumes of such materials, now used in 65 countries. EMERALD developed e-Learning materials in three areas of medical physics (X-ray diagnostic radiology, nuclear medicine and radiotherapy). EMIT developed e-Learning materials in two further areas: ultrasound and magnetic resonance imaging. This paper describes the development of these e-Learning materials (consisting of e-books and educational image databases). The e-books include tasks helping studying of various equipment and methods. The text of these PDF e-books is hyperlinked with respective images. The e-books are used through the readers' own Internet browser. Each Image Database (IDB) includes a browser, which displays hundreds of images of equipment, block diagrams and graphs, image quality examples, artefacts, etc. Both the e-books and IDB are engraved on five separate CD-ROMs. Demo of these materials can be taken from www.emerald2.net.

Mutations in Cdh23 cause nonsyndromic hearing loss in waltzer mice

Mutations at the waltzer (v) locus result in deafness and vestibular dysfunction due to degeneration of the neuroepithelium within the inner ear. Here, we use a positional cloning approach to show that waltzer encodes a novel cadherin (Cdh23), which is most closely related to the Drosophila Fat protein. A single nucleotide deletion in the v(J) allele and a single nucleotide insertion in the v allele are predicted to truncate each protein near the N-terminus and produce a functional null allele. In situ hybridization analysis showed that Cdh23 is expressed in the sensory hair cells of the inner ear, where it has been suggested to be a molecule critical for crosslinking of the stereocilia. In addition, Cdh23 is expressed in the urticulo-saccular foramen,the ductus reuniens, and Reissner's membrane, suggesting that Cdh23 may also be involved in maintaining the ionic composition of the endolymph. Finally, mutations in human CDH23 have recently been described for two loci, DFNB12 and USH1D, which cause nonsyndromic deafness, identifying waltzer as a mouse model for human hearing loss.

Deletion of Dad1 in mice induces an apoptosis-associated embryonic death

Dad1 is a putative anti-apoptosis gene identified in several distantly related organisms. Expression of Dad1 in transfected cells inhibits apoptosis in vitro. To determine whether Dad1 has a similar function in vivo, we used gene targeting to delete Dad1. Heterozygous adult mice (+/-) show no obvious phenotype or abnormalities, but genotype analysis of over 100 offspring from heterozygous matings detected no weanling, homozygous Dad1 null (-/-) mice. Subsequent analysis of embryos from heterozygous matings detected Dad1 null (-/-) embryos at E3.5 but no later, suggesting Dad1 is required for development beyond the late blastocyst stage. Increased levels of apoptosis were observed in cultured embryos lacking a functional copy of the gene, consistent with an anti-apoptotic role for Dad1.

Absence of the tight junctional protein AF-6 disrupts epithelial cell-cell junctions and cell polarity during mouse development

BACKGROUND

The establishment, maintenance and rearrangement of junctions between epithelial cells are extremely important in many developmental, physiological and pathological processes. AF-6 is a putative Ras effector; it is also a component of tight and adherens junctions, and has been shown to bind both Ras and the tight-junction protein ZO-1. In the mouse, AF-6 is encoded by the Af6 gene. As cell-cell junctions are important in morphogenesis, we generated a null mutation in the murine Af6 locus to test the hypothesis that lack of AF-6 function would cause epithelial abnormalities.

RESULTS

Although cell-cell junctions are thought to be important in early embryogenesis, homozygous mutant embryos were morphologically indistinguishable from wild-type embryos through 6.5 days post coitum (dpc) and were able to establish all three germ layers. The earliest morphological abnormalities were observed in the embryonic ectoderm of mutant embryos at 7.5 dpc. The length of the most apical cell-cell junctions was reduced, and basolateral surfaces of those cells were separated by multiple gaps. Cells of the embryonic ectoderm were less polarized as assessed by histological criteria and lateral localization of an apical marker. Mutant embryos died by 10 dpc, probably as a result of placental failure.

CONCLUSIONS

AF-6 is a critical regulator of cell-cell junctions during mouse development. The loss of neuroepithelial polarity in mutants is consistent with a loss of efficacy of the cell-cell junctions that have a critical role in establishing apical/basolateral asymmetry.

Transplant renal artery stenosis in 77 patients--does it have an immunological cause?

Transplant renal artery stenosis (TRAS) is a common complication after transplantation and is an important cause of graft dysfunction. Damage from graft rejection, trauma, and atherosclerosis have been implicated as possible causes. We reviewed all 917 patients transplanted in our unit since 1978 to study the prevalence, clinical features, and possible causes of TRAS. Seventy-seven patients with TRAS were identified. The detected incidence was 2.4% before the introduction of color doppler ultrasonography (CDU) and rose to 12.4% after CDU was introduced in 1985, giving an overall incidence of 8.4% during a mean follow-up period of 6.9 years. The TRAS group was compared with a control group of 77 transplanted patients matched for age, year of transplant, sex, and number of previous grafts. Mean ages for the study and control groups were 43.6 +/- 15 and 44.8 +/- 13.7 yr. A total of 25% of cases of TRAS were diagnosed within the first 8 wk of transplantation and in 60% within the first 30 wk (median = 23 wk). All patients were treated with angioplasty, 28 patients had recurrence of TRAS requiring multiple angioplasties (maximum 5) and 1 went on to have surgery. Angioplasty resulted in a significant fall in plasma creatinine. Patient and graft survival were significantly worse in the TRAS group: 69% vs. 83% (P < 0.05) and 56% vs. 74% (P < 0.05) (TRAS vs. Control), respectively. There was a significantly higher incidence of rejection, especially cellular rejection in the TRAS group, 0.67 vs. 0.35 episodes per patient (P < 0.01) (TRAS vs. Control). Recurrence but not occurrence of TRAS was associated with the use of cyclosporine.

Structure-function analysis of Escherichia coli translation initiation factor IF3: tyrosine 107 and lysine 110 are required for ribosome binding

Translation initiation factor IF3 is required for peptide chain initiation in Escherichia coli. IF3 binds directly to 30S ribosomal subunits ensuring a constant supply of free 30S subunits for initiation complex formation, participates in the kinetic selection of the correct initiator region of mRNA, and destabilizes initiation complexes containing noninitiator tRNAs. The roles that tyrosine 107 and lysine 110 play in IF3 function were examined by site-directed mutagenesis. Tyrosine 107 was changed to either phenylalanine (Y107F) or leucine (Y107L), and lysine 110 was converted to either arginine (K110R) or leucine (K110L). These single amino acid changes resulted in a reduced affinity of IF3 for 30S subunits. Association equilibrium constants (M-1) for 30S subunit binding were as follows: wild-type, 7.8 x 10(7); Y107F, 4.1 x 10(7); Y107L, 1 x 10(7); K110R, 5.1 x 10(6); K110L, < 1 x 10(2). The mutant IF3s were similarly impaired in their abilities to specifically select initiation complexes containing tRNA(fMet). Toeprint analysis indicated that 5-fold more Y107L or K110R protein was required for proper initiator tRNA selection. K110L protein was unable to mediate this selection even at concentrations up to 10-fold higher than wild type. The results indicate that tyrosine 107 and lysine 110 are critical components of the ribosome binding domain of IF3 and, furthermore, that dissociation of complexes containing noninitiator tRNAs requires prior binding of IF3 to the ribosomes.

A six year prospective study of fibrinogen and other risk factors associated with mortality in stable claudicants

A total of 333 patients with stable intermittent claudication at recruitment were followed up for 6 years to determine risk factors associated with subsequent mortality. Cardiovascular diseases were the underlying cause of death in 78% of the 114 patients who died. The strongest independent predictor of death during the follow-up period was the plasma fibrinogen level, an increase of 1 milligram being associated with a nearly two-fold increase in the probability of death within the next 6 years. Age, low ankle/brachial pressure index and a past history of myocardial infarction also increased the probability of death during the study period. The plasma fibrinogen level is a valuable index of those patients with stable intermittent claudication at high risk of early mortality. The results also provide further evidence for the involvement of fibrinogen in the pathogenesis of arterial disease.