Genomic DNA pooling for whole-genome association scans in complex disease: empirical demonstration of efficacy in rheumatoid arthritis

A pragmatic approach that balances the benefit of a whole-genome association (WGA) experiment against the cost of individual genotyping is to use pooled genomic DNA samples. We aimed to determine the feasibility of this approach in a WGA scan in rheumatoid arthritis (RA) using the validated human leucocyte antigen (HLA) and PTPN22 associations as test loci. A total of 203 269 single-nucleotide polymorphisms (SNPs) on the Affymetrix 100K GeneChip and Illumina Infinium microarrays were examined. A new approach to the estimation of allele frequencies from Affymetrix hybridization intensities was developed involving weighting for quality signals from the probe quartets. SNPs were ranked by z-scores, combined from United Kingdom and New Zealand case-control cohorts. Within a 1.7 Mb HLA region, 33 of the 257 SNPs and at PTPN22, 21 of the 45 SNPs, were ranked within the top 100 associated SNPs genome wide. Within PTPN22, individual genotyping of SNP rs1343125 within MAGI3 confirmed association and provided some evidence for association independent of the PTPN22 620W variant (P=0.03). Our results emphasize the feasibility of using genomic DNA pooling for the detection of association with complex disease susceptibility alleles. The results also underscore the importance of the HLA and PTPN22 loci in RA aetiology.

Primary thromboprophylaxis for cancer patients with central venous catheters--a reappraisal of the evidence

Venous thromboembolism (VTE) is responsible for an estimated 25 000 deaths per annum in UK hospital practice. It is well established that many of these deaths could be prevented through the use of appropriate thromboprophylaxis. This issue is of particular relevance in oncology practice, where the risks of VTE and bleeding are both significantly higher than those observed in general medical patients. Cancer patients with in-dwelling central venous catheters (CVCs) are at particularly high risk of developing thrombotic complications. However, the literature has produced conflicting conclusions regarding the efficacy of using routine primary thromboprophylaxis in these patients. Indeed such is the level of confusion around this topic, that the most recent version of the American College of Chest Physicians (ACCP) guidelines published in 2004 actually reversed their previous recommendation (published in 2001). Nevertheless, minidose warfarin continues to be routinely used in many oncology centres in the UK. In this article, we have performed a systematic review of the published literature regarding the efficacy and the risks, associated with using thromboprophylaxis (either minidose warfarin or low-dose LMWH) in cancer patients with CVC. On the basis of this evidence, we conclude that there is no proven role for using such thromboprophylaxis. However, asymptomatic CVC-related venous thrombosis remains common, and further more highly powered studies of better design are needed in order to define whether specific subgroups of cancer patients might benefit from receiving thromboprophylaxis.

Prevention and Management of Venous Thromboembolism in People with Cancer: A Review of the Evidence

Venous thromboembolism (VTE) constitutes an important health problem in developed countries. Owing to their underlying malignancies, people with cancer are at particularly high risk of VTE. The level of this risk is influenced by several factors, including type of cancer and the presence or absence of metastases. However, different types of oncology treatment can also further increase the thrombotic risk. Consequently, primary and secondary thromboprophylaxis in people with cancer should be considered as part of any integrated oncology treatment. Moreover, recent exciting studies have suggested that low molecular weight heparins (LMWH) may also influence overall survival in people with cancer. Clearly, these findings raise the likelihood that the use of LMWH in oncology practice may increase significantly in the near future. However, it is important to appreciate that the use of thromboprophylaxis in people with cancer is complicated by a number of specific problems. In this overview, we have systematically addressed the difficult clinical issues that are involved in the selection of appropriate primary and secondary thromboprophylaxis for people with cancer.

Improving Clinical Practice: Should We Give Influenza Vaccinations to Heart Transplant Patients?

BACKGROUND

Current practice recommends that immunosuppressed patients (pts) receive yearly influenza (flu) vaccinations. However, disparity exists between current recommendations and clinical practice regarding the decision to administer flu vaccinations to heart transplant (Tx) pts. The purpose of this study was to examine the common clinical practices and outcome characteristics in Tx pts in a multi-institutional database. We assess the incidence of rejection, infection and flu in the months after administration of flu vaccinations.

METHODS

Between 1990 and 2001, 5,581 pts underwent Tx at 28 institutions. Pts who were >1 year post-Tx as of January 1, 2002 (N = 3,601) constituted the study group.

RESULTS

During the years 2002 and 2003, 89% of the institutions administered flu vaccines, with 7 institutions requiring pts to be >3 months (N = 1), 6 months (N = 1) and 12 months (N = 5) post-Tx. All 25 centers that vaccinated pts used trivalent inactivated vaccines during the months of October through January. Three centers did not vaccinate Tx pts due to a purported association with increased allograft rejection. There were no significant differences in the total number of rejection episodes (0.4% vs 0.3%, p = 0.7), rejection episodes by month (January: 0.4% vs 0%, p = 0.2; February: 0.5% vs 1.5%, p = 0.08; March: 0.5% vs 0%, p = 0.14), all infections (0.7% vs 0.6%, p = 0.6) and viral infections (0.1% vs 0%, p = 0.17) between centers that administered flu vaccines and those that did not, respectively. The incidence of flu was low in both groups.

CONCLUSIONS

Flu vaccinations can be given safely to heart transplant pts without an increased incidence of rejection or infection. This information provides clinicians with data to improve clinical practice.

Warfarin, hematoma expansion, and outcome of intracerebral hemorrhage

BACKGROUND

Warfarin increases mortality of intracerebral hemorrhage (ICH). The authors investigated whether this effect reflects increased baseline ICH volume at presentation or increased ICH expansion.

METHODS

Subjects were drawn from an ongoing prospective cohort study of ICH outcome. The effect of warfarin on baseline ICH volume was studied in 183 consecutive cases of supratentorial ICH age > or = 18 years admitted to the emergency department over a 5-year period. Baseline ICH volume was determined using computerized volumetric analysis. The effect of warfarin on ICH expansion (increase in volume > or = 33% of baseline) was analyzed in 70 consecutive cases in whom ICH volumes were measured on all subsequent CT scans up to 7 days after admission. Multivariable analysis was used to determine warfarin's influence on baseline ICH, ICH expansion, and whether warfarin's effect on ICH mortality was dependent on baseline volume or subsequent expansion.

RESULTS

There was no effect of warfarin on initial volume. Predictors of larger baseline volume were hyperglycemia (p < 0.0001) and lobar hemorrhage (p < 0.0001). Warfarin patients were at increased risk of death, even when controlling for ICH volume at presentation. Warfarin was the sole predictor of expansion (OR 6.2, 95% CI 1.7 to 22.9) and expansion in warfarin patients was detected later in the hospital course compared with non-warfarin patients (p < 0.001). ICH expansion showed a trend toward increased mortality (OR 3.5, 95% CI 0.7 to 8.9, p = 0.14) and reduced the marginal effect of warfarin on ICH mortality.

CONCLUSIONS

Warfarin did not increase ICH volume at presentation but did raise the risk of in-hospital hematoma expansion. This expansion appears to mediate part of warfarin's effect on ICH mortality.

Increased influenza activity in Ireland, January 2005

During week 1/2005 (week ending 9 January), influenza activity in Ireland showed a marked increase from previous weeks. However, this was followed by a rapid decline in week 2/2005

Management of patients undergoing splenectomy in an Irish teaching hospital: impact of guidelines

INTRODUCTION

Overwhelming post-splenectomy infection (OPSI) has a 50-70% mortality rate and carries a lifetime risk for the asplenic patient. Specific British guidelines have been developed to reduce its incidence.

AIMS

To determine whether British guidelines were being followed in our own institution and what impact they had on overwhelming post-splenectomy infection.

METHODS

Retrospective chart review of 100 splenectomies performed by Department of Surgery, Beaumont Hospital from January 1990 to January 2000.

RESULTS

Twenty per cent of patients were discharged without any recommended vaccinations. Prophylactic antibiotics were not prescribed in 53% of patients. Just 12% of charts document a verbal explanation of the complications and management of asplenia to the patient. Overall septic mortality was 12%, of whom 8% died in hospital and 4% after discharge.

CONCLUSION

Management of the asplenic patient has improved but is far from complete. A central register of asplenic patients and national asplenic guidelines should be established in Ireland to ensure optimum patient care.

Achieving Normothermia in Patients With Febrile Subarachnoid Hemorrhage: Feasibility and Safety of a Novel Intravascular Cooling Catheter

INTRODUCTION

Fever is common and difficult to control in patients with subarachnoid hemorrhage (SAH). We have previously shown an inverse relationship between fever and outcome in patients with SAH.

MATERIALS/METHODS

This was a prospective, single-arm, feasibility trial in which nine patients with SAH underwent temperature management using an intravascular cooling catheter (ICC) to restore and maintain 24 hours of normothermia (36.5 degrees+/-0.2 degrees C). Enrollment occurred after development of a fever of at least 38.3 degrees C within 7 days of SAH that was refractory to acetaminophen treatment. The ICC was placed at the bedside through an introducer sheath via the femoral vein into the inferior vena cava (IVC). Portable X-ray confirmed placement.

RESULTS

Normothermia was achieved in seven of the nine patients treated (78%); it was achieved in 100% of the patients with a 14F catheter (n=4) and in 60% of the patients with a 9F catheter (n=5). The two patients not reaching normothermia were not adequately treated for shivering. All other patients reached normothermia irrespective of intubation status. Overall, normothermia was well tolerated and not discontinued because of discomfort or adverse events. Two incidences of deep vein thrombosis were diagnosis by ultrasound that were not associated with clinical sequelae, and IVC filters were placed. No unanticipated adverse events occurred.

DISCUSSION

We have demonstrated that fever can be safely and effectively controlled in patients with SAH for at least 24 hours using an ICC. Future studies are needed to assess the effect of such sustained therapy on outcome in patients with SAH.

Never forget the risks of immunosuppression

It has been widely reported in the literature that malignant neoplasms are a recognised complication of immunosuppression following organ transplantation. These days, immunosuppressive drugs are being used for many conditions outside the transplant setting. A case of a de novo astrocytoma in a patient on long-term immunosuppression for psoriatic arthritis is described.

Neuronal and inducible nitric oxide synthase expressions and activities in the hippocampi and cortices of young adult, aged cognitively unimpaired, and impaired Long-Evans rats

Nitric oxide (NO) is a neurosignaling molecule that appears to play a significant role in learning and memory. This molecule has also been implicated in neurotoxicity due to its oxidative properties. Previous experiments from our laboratories have demonstrated elevated hippocampal and cortical neuronal nitric oxide synthase (NOS) mRNA levels in aged cognitively unimpaired and impaired Long-Evans rats, which could represent either increased neuronal NOS activity thereby leading to NO-mediated neurotoxicity, or a compensatory response by aged neurones to maintain physiological nitric oxide output. The current study measured the protein expression and activity levels of neuronal and inducible NOS in young adult (6 months) and aged (24-26 months) Long-Evans rats by means of western blotting and NOS activity assay. Aged animals were assigned as either cognitively unimpaired or aged with moderate cognitive impairments based on their performances in the Morris water maze behavioural task. Our results showed that hippocampal and cortical neuronal NOS expressions were significantly decreased in aged animals. These aged animals also exhibited increased hippocampal and cortical inducible NOS expressions. Between the two aged animal groups, cognitively impaired rats showed significantly lower hippocampal and cortical neuronal but higher hippocampal inducible NOS expressions. Young adult rats exhibited significantly higher hippocampal and cortical NOS activities than the aged animals. Aged animals with cognitive deficits showed significantly lower hippocampal NOS activity than cognitively unimpaired aged rats. Our data indicate that aging is associated with a decline in neuronal but elevated inducible NOS functioning in brain areas involved in learning and memory. These phenomena could contribute to the cognitive deficits observed in a sub-population of aged animals.

Use of analgesia in a paediatric accident and emergency department following limb trauma

The objective of this study was to assess analgesic use and the use of a pain scoring system on those children presenting to a paediatric accident and emergency (A&E) department with a history of injury due to trauma. A random sample of patients who presented to a paediatric A&E department over a 6-week period with a history of limb trauma were prospectively studied. Pain severity scores were assessed on arrival and at 10, 30 and 60 minutes using the Douhit Faces Scale and any analgesia given or plaster application was noted. One hundred and seventy-two patients were studied. The median age was 10 years (range 3-13 years) and the majority, 56%, were male. The mean initial pain scores were 2.7 (range 1-4) for boys and 3.0 (range 1-4) for girls. The presenting injuries were 103 upper or lower limb fractures and 69 'soft tissue' injuries. Only 84 (49%) patients received analgesic medication in the department (30% morphine; 70% paracetamol); analgesia was not given to the remaining 88 (51%). Of these, 7 declined analgesia, and 5 had already taken analgesia on arrival to A&E. Despite prompt triage (median time 2 minutes, range 0-10 minutes), the median time from arrival to paracetamol administration was 20 minutes (range 4-105 minutes) and for morphine was 14 minutes (range 2-57 minutes). Pain is a common symptom in patients presenting to A&E. Because children's pain can be particularly difficult to assess, a pain scoring system such as the Douhit Faces Scale can be a useful means of pain assessment in the A&E setting. Despite increased awareness, pain is still under treated in the A&E department.

Granulocyte-macrophage colony-stimulating factor (GM-CSF) priming with successive concomitant low-dose Ara-C for elderly patients with secondary/refractory acute myeloid leukemia or advanced myelodysplastic syndrome

Patients with advanced MDS and secondary AML respond poorly to chemotherapy. Granulocyte-macrophage colony-stimulating factor (GM-CSF) can stimulate proliferation of leukemic blasts and sensitize these cells to the cytotoxic effects of S-phase-specific drugs. This is the first report of safety and efficacy of GM-CSF prior to and during cytarabine in a low-dose, intermittent regimen for elderly patients with poor risk acute myelogenous leukemia or myelodysplastic syndrome. Twenty patients, age 68 to 86 years, each received 250 microg/m2 of GM-CSF (Sargramostatin; Immunex, Seattle, WA, USA) subcutaneously (s.c.) or intravenously (i.v.) for 3 days followed by GM-CSF at the same dose and cytarabine 100 mg/m2 i.v. for 3 days. GM-CSF and cytarabine were both administered for 3 days during weeks 2 and 3 followed by a 3-week rest period. Rates of CR and PR were 20% and 40%, respectively. These included clinically significant resolution of cytopenias and transfusion requirements. Many of the responding patients had been heavily pretreated prior to enrollment. One- and 2-year survival estimates are 44% and 19%, respectively. Myelosuppression was the most significant toxicity. Our findings suggest that this novel combination of GM-CSF with sequential and concomitant low-dose cytarabine can benefit patients with poor risk myeloid malignancies.

Marked elevation of thrombin generation in patients with elevated FVIII:C and venous thromboembolism

Elevated plasma factor VIII coagulant activity (FVIII:C, > 150 IU/dl) is a risk factor for venous thromboembolism (VTE). We hypothesized that increased FVIII:C may exert a prothrombotic effect by increasing basal thrombin generation. To test this hypothesis we have measured prothrombin fragment 1 + 2 (F1 + 2) and thrombin-antithrombin complex (TAT) in three groups: (i) patients with objectively confirmed VTE and elevated FVIII:C; (ii) patients with VTE and no detectable thrombophilia; and (iii) healthy age- and sex-matched control subjects. In the group of patients with elevated FVIII:C, TAT and F1 + 2 levels were increased in 85% and 78% of individuals respectively. This frequency of coagulation activation is dramatically higher than that reported for other recognized constitutional thrombophilias. In the group of patients with VTE but no proven thrombophilia, increased thrombin generation was present in 30% of individuals. Basal thrombin generation was significantly higher in patients with elevated FVIII:C compared with individuals with VTE but no documented thrombophilia (median TAT = 8.65 microg/l versus 2.95 microg/l, median F1 + 2 = 1.5 nmol/l versus 0.87 nmol/l; P < 0.0001, P < 0.001). Overall FVIII:C levels were strongly correlated with levels of thrombin generation (r= 0.5, P < 0001). The clinical significance of such markedly increased F1 + 2 and TAT levels in patients with high FVIII:C levels remains unclear.

Potential influence of acute CT on inpatient costs in patients with ischemic stroke

RATIONALE AND OBJECTIVES

Patients presenting with ischemic brain symptoms have widely variable outcomes dependent to some degree on the pathologic basis of their stroke syndrome. The purpose of this study was to determine the cost implications of the emergency use of a computed tomographic (CT) protocol comprising unenhanced CT, head and neck CT angiography, and whole-brain CT perfusion.

MATERIALS AND METHODS

By using a retrospective patient database from a tertiary care facility and publicly available cost data, the authors derived the potential savings from the use of CT angiography. CT perfusion, or both at hospital arrival by means of a cost model. The cost of the CT angiography-CT perfusion protocol was determined from Medicare reimbursement rates and compared with that of traditional imaging protocols. Cost savings were estimated as a decrease in the length of stay for most stroke patients, whereas the most benign (lacunar) strokes were assumed to be managed in a non-acute setting. Misdiagnosis cost (erroneously not admitting a patient with nonlacunar stroke) was calculated as the cost of a severe complication. Sensitivity testing included varying the percentage of misdiagnosed patients and admitting patients with lacunar stroke.

RESULTS

The nationwide net savings that would result from the adoption of the CT angiography-CT perfusion protocol are in the $1.2 billion range (-$154 million to $2.1 billion) when patients with lacunar strokes are treated nonacutely and $1.8 billion when those patients are admitted for acute care.

CONCLUSION

The results demonstrate the potential effect of implementing a CT angiography-CT perfusion protocol. In particular, prompt CT angiography-CT perfusion imaging could have an effect on the cost of acute care in the treatment of stroke.

Spiritual and religious components of patient care in the neonatal intensive care unit: sacred themes in a secular setting

OBJECTIVE

We hypothesized that spiritual distress was a common, unrecognized theme for neonatal intensive care unit (NICU) care providers.

STUDY DESIGN

An anonymous questionnaire form assigned to a data table in a relational database was designed.

RESULTS

Surveys were completed by 66% of NICU staff. All respondents viewed a family's spiritual and religious concerns as having a place in patient care. Eighty-three percent reported praying for babies privately. Asked what theological sense they made of suffering of NICU babies, 2% replied that children do not suffer in the NICU. Regarding psychological suffering of families, the majority felt God could prevent this, with parents differing (p = 0.039) from nonparents.

CONCLUSION

There exists a strong undercurrent of spirituality and religiosity in the study NICU. These data document actual religious and spiritual attitudes and practices and support a need for pastoral resources for both families and care providers. NICU care providers approach difficulties of their work potentially within a religious and spiritual rather than a uniquely secular framework.

The relationship between ABO histo-blood group, factor VIII and von Willebrand factor

ABO histo-blood group is a major determinant of plasma levels of factor VIII (FVIII) and von Willebrand factor (vWF). Blood group O individuals have significantly (approximately 25%) lower plasma levels of both glycoproteins. This association is of clinical significance. Low plasma levels of either FVIII or vWF have long been established as causes of excess bleeding. Conversely, there is accumulating evidence that elevated FVIII-vWF levels may represent an important risk factor for ischaemic heart disease and venous thromboembolic disease. In spite of the well-documented association between ABO blood group and FVIII-vWF levels, the underlying mechanism remains unknown. However, it has been established that the ABO effect is primarily mediated through a direct functional effect of the ABO locus on plasma vWF levels. Theoretically, ABO blood group may alter the rate of vWF synthesis or secretion within endothelial cells. Alternatively, ABO group may affect vWF plasma clearance rates. ABH antigenic determinants have been identified on the N-linked oligosaccharide chains of circulating vWF and FVIII, according to the blood group of the individual. It remains unclear whether these carbohydrate structures are responsible for mediating the effect of ABO blood group on plasma vWF levels.

Undisclosed port-wine stain--anesthetic implications and psychosocial considerations: a case report

Port-wine stains (nevus flammeus, port-wine nevus) are congenital vascular lesions that have psychological and physiological implications for patient care. The location and size of these lesions can lead to complications related to anesthetic management. Facial lesions have the most profound psychological effect on the patient with respect to behavior alterations and reluctance to disclose the lesion's presence. Covering makeup has become increasingly effective not only in concealing the lesion, but also in being nearly undetectable during routine examination. Issues such as agent choice, surgical position, frequency of positioning evaluation, and choice of intravenous fluid should be considered when caring for a patient with a port-wine stain. In this case study the authors describe the anesthesia implications and outcome in a patient who refused to disclose her port-wine lesion in the preoperative interview and who ignored preoperative instructions to remove all makeup before presenting for surgery.

Elevated plasma factor VIII levels--a novel risk factor for venous thromboembolism

An association between elevated plasma levels of FVIII:C and arterial thrombosis was first described 20 years ago. More recently a growing literature has centered on the potential role for elevated FVIII:C in venous thromboembolic disease. 25% of patients have plasma FVIII:C levels greater than 1500 IU/l six months following venous thrombosis. This increased FVIII:C appears unrelated to any ongoing acute phase reaction, and reflects a true increase in circulating FVIII protein. Furthermore the increase in FVIII:C is sustained in the vast majority of subjects for years following the thrombotic episode. Multivariate analysis of the Leiden thrombophilia study has demonstrated that increased FVIII is an independent risk factor for venous thromboembolism. Individuals with FVIII:C exceeding 1500 IU/l had a six-fold increased risk, compared to those with FVIII:C levels less than 1000 IU/l. Also, prospective follow-up has shown that patients with high FVIII:C levels are at increased risk for episodes of recurrent venous thrombosis. These findings support the theory that increased plasma levels of FVIII:C represent a constitutional prothrombotic tendency. However the mechanism underlying the elevation in FVIII remains unknown.

Post-translational modifications of the beta-1 subunit of AMP-activated protein kinase affect enzyme activity and cellular localization

The AMP-activated protein kinase (AMPK) is a ubiquitous mammalian protein kinase important in the adaptation of cells to metabolic stress. The enzyme is a heterotrimer, consisting of a catalytic alpha subunit and regulatory beta and gamma subunits, each of which is a member of a larger isoform family. The enzyme is allosterically regulated by AMP and by phosphorylation of the alpha subunit. The beta subunit is post-translationally modified by myristoylation and multi-site phosphorylation. In the present study, we have examined the impact of post-translational modification of the beta-1 subunit on enzyme activity, heterotrimer assembly and subcellular localization, using site-directed mutagenesis and expression of subunits in mammalian cells. Removal of the myristoylation site (G2A mutant) results in a 4-fold activation of the enzyme and relocalization of the beta subunit from a particulate extranuclear distribution to a more homogenous cell distribution. Mutation of the serine-108 phosphorylation site to alanine is associated with enzyme inhibition, but no change in cell localization. In contrast, the phosphorylation site mutations, SS24, 25AA and S182A, while having no effects on enzyme activity, are associated with nuclear redistribution of the subunit. Taken together, these results indicate that both myristoylation and phosphorylation of the beta subunit of AMPK modulate enzyme activity and subunit cellular localization, increasing the complexity of AMPK regulation.