Chemical Validation of Mycobacterium tuberculosis Phosphopantetheine Adenylyltransferase Using Fragment Linking and CRISPR Interference

The coenzyme A (CoA) biosynthesis pathway has attracted attention as a potential target for much-needed novel antimicrobial drugs, including for the treatment of tuberculosis (TB), the lethal disease caused by Mycobacterium tuberculosis (Mtb). Seeking to identify inhibitors of Mtb phosphopantetheine adenylyltransferase (MtbPPAT), the enzyme that catalyses the penultimate step in CoA biosynthesis, we performed a fragment screen. In doing so, we discovered three series of fragments that occupy distinct regions of the MtbPPAT active site, presenting a unique opportunity for fragment linking. Here we show how, guided by X-ray crystal structures, we could link weakly-binding fragments to produce an active site binder with a K D <20 μM and on-target anti-Mtb activity, as demonstrated using CRISPR interference. This study represents a big step toward validating MtbPPAT as a potential drug target and designing a MtbPPAT-targeting anti-TB drug.

Chemical Validation of Mycobacterium tuberculosis Phosphopantetheine Adenylyltransferase Using Fragment Linking and CRISPR Interference

The coenzyme A (CoA) biosynthesis pathway has attracted attention as a potential target for much-needed novel antimicrobial drugs, including for the treatment of tuberculosis (TB), the lethal disease caused by Mycobacterium tuberculosis (Mtb). Seeking to identify inhibitors of Mtb phosphopantetheine adenylyltransferase (MtbPPAT), the enzyme that catalyses the penultimate step in CoA biosynthesis, we performed a fragment screen. In doing so, we discovered three series of fragments that occupy distinct regions of the MtbPPAT active site, presenting a unique opportunity for fragment linking. Here we show how, guided by X-ray crystal structures, we could link weakly-binding fragments to produce an active site binder with a KD <20 μM and on-target anti-Mtb activity, as demonstrated using CRISPR interference. This study represents a big step toward validating MtbPPAT as a potential drug target and designing a MtbPPAT-targeting anti-TB drug.

Expanding the knowledge around antitubercular 5-(2-aminothiazol-4-yl)isoxazole-3-carboxamides: Hit-to-lead optimization and release of a novel antitubercular chemotype via scaffold derivatization

Tuberculosis is one of the deadliest infectious diseases in the world, and the increased number of multidrug-resistant and extensively drug-resistant strains is a reason for concern. We have previously reported a series of substituted 5-(2-aminothiazol-4-yl)isoxazole-3-carboxamides with growth inhibitory activity against Mycobacterium tuberculosis strains and low propensity to be substrate of efflux pumps. Encouraged by these preliminary results, we have undertaken a medicinal chemistry campaign to determine the metabolic fate of these compounds and to delineate a reliable body of Structure-Activity Relationships. Keeping intact the (thiazol-4-yl)isoxazole-3-carboxamide core, as it is deemed to be the pharmacophore of the molecule, we have extensively explored the structural modifications able to confer good activity and avoid rapid clearance. Also, a small set of analogues based on isostere manipulation of the 2-aminothiazole were prepared and tested, with the aim to disclose novel antitubercular chemotypes. These studies, combined, were instrumental in designing improved compounds such as 42g and 42l, escaping metabolic degradation by human liver microsomes and, at the same time, maintaining good antitubercular activity against both drug-susceptible and drug-resistant strains.

The Myxobacterial Antibiotic Myxovalargin: Biosynthesis, Structural Revision, Total Synthesis, and Molecular Characterization of Ribosomal Inhibition

Resistance of bacterial pathogens against antibiotics is declared by WHO as a major global health threat. As novel antibacterial agents are urgently needed, we re-assessed the broad-spectrum myxobacterial antibiotic myxovalargin and found it to be extremely potent against Mycobacterium tuberculosis. To ensure compound supply for further development, we studied myxovalargin biosynthesis in detail enabling production via fermentation of a native producer. Feeding experiments as well as functional genomics analysis suggested a structural revision, which was eventually corroborated by the development of a concise total synthesis. The ribosome was identified as the molecular target based on resistant mutant sequencing, and a cryo-EM structure revealed that myxovalargin binds within and completely occludes the exit tunnel, consistent with a mode of action to arrest translation during a late stage of translation initiation. These studies open avenues for structure-based scaffold improvement toward development as an antibacterial agent.

Targeting Mycobacterium tuberculosis CoaBC through Chemical Inhibition of 4'-Phosphopantothenoyl-l-cysteine Synthetase (CoaB) Activity

Coenzyme A (CoA) is a ubiquitous cofactor present in all living cells and estimated to be required for up to 9% of intracellular enzymatic reactions. Mycobacterium tuberculosis (Mtb) relies on its own ability to biosynthesize CoA to meet the needs of the myriad enzymatic reactions that depend on this cofactor for activity. As such, the pathway to CoA biosynthesis is recognized as a potential source of novel tuberculosis drug targets. In prior work, we genetically validated CoaBC as a bactericidal drug target in Mtb in vitro and in vivo. Here, we describe the identification of compound 1f, a small molecule inhibitor of the 4'-phosphopantothenoyl-l-cysteine synthetase (PPCS; CoaB) domain of the bifunctional Mtb CoaBC, and show that this compound displays on-target activity in Mtb. Compound 1f was found to inhibit CoaBC uncompetitively with respect to 4'-phosphopantothenate, the substrate for the CoaB-catalyzed reaction. Furthermore, metabolomic profiling of wild-type Mtb H37Rv following exposure to compound 1f produced a signature consistent with perturbations in pantothenate and CoA biosynthesis. As the first report of a direct small molecule inhibitor of Mtb CoaBC displaying target-selective whole-cell activity, this study confirms the druggability of CoaBC and chemically validates this target.

Inhibiting Mycobacterium tuberculosis CoaBC by targeting an allosteric site

Coenzyme A (CoA) is a fundamental co-factor for all life, involved in numerous metabolic pathways and cellular processes, and its biosynthetic pathway has raised substantial interest as a drug target against multiple pathogens including Mycobacterium tuberculosis. The biosynthesis of CoA is performed in five steps, with the second and third steps being catalysed in the vast majority of prokaryotes, including M. tuberculosis, by a single bifunctional protein, CoaBC. Depletion of CoaBC was found to be bactericidal in M. tuberculosis. Here we report the first structure of a full-length CoaBC, from the model organism Mycobacterium smegmatis, describe how it is organised as a dodecamer and regulated by CoA thioesters. A high-throughput biochemical screen focusing on CoaB identified two inhibitors with different chemical scaffolds. Hit expansion led to the discovery of potent and selective inhibitors of M. tuberculosis CoaB, which we show to bind to a cryptic allosteric site within CoaB.

Prenatal exposure to maternal cigarette smoking and structural properties of the human corpus callosum

Alterations induced by prenatal exposure to nicotine have been observed in experimental (rodent) studies. While numerous developmental outcomes have been associated with prenatal exposure to maternal cigarette smoking (PEMCS) in humans, the possible relation with brain structure is less clear. Here we sought to elucidate the relation between PEMCS and structural properties of human corpus callosum in adolescence and early adulthood in a total of 1,747 youth. We deployed three community-based cohorts of 446 (age 25-27 years, 46% exposed), 934 (age 12-18 years, 47% exposed) and 367 individuals (age 18-21 years, 9% exposed). A mega-analysis revealed lower mean diffusivity in the callosal segments of exposed males. We speculate that prenatal exposure to maternal cigarette smoking disrupts the early programming of callosal structure and increases the relative portion of small-diameter fibres.

Priming the tuberculosis drug pipeline: new antimycobacterial targets and agents

Claiming close to two million lives each year, tuberculosis is now the leading cause of death from an infectious disease. The rise in number of Mycobacterium tuberculosis (Mtb) strains resistant to existing TB drugs has underscored the urgent need to develop new antimycobacterials with novel mechanisms of action. To meet this need, a drug pipeline has been established that is populated with new and repurposed drugs. Recent advances in identifying molecules with inhibitory activity against Mtb under conditions modelled on those encountered during infection, and in elucidating their mechanisms of action, have primed the pipeline with promising drug/target couples, hit compounds and new targets. In this review, we highlight recent advances and emerging areas of opportunity in this field.

The Influence of HIV on the Evolution of Mycobacterium tuberculosis

HIV significantly affects the immunological environment during tuberculosis coinfection, and therefore may influence the selective landscape upon which M. tuberculosis evolves. To test this hypothesis whole genome sequences were determined for 169 South African M. tuberculosis strains from HIV-1 coinfected and uninfected individuals and analyzed using two Bayesian codon-model based selection analysis approaches: FUBAR which was used to detect persistent positive and negative selection (selection respectively favoring and disfavoring nonsynonymous substitutions); and MEDS which was used to detect episodic directional selection specifically favoring nonsynonymous substitutions within HIV-1 infected individuals. Among the 25,251 polymorphic codon sites analyzed, FUBAR revealed that 189-fold more were detectably evolving under persistent negative selection than were evolving under persistent positive selection. Three specific codon sites within the genes celA2b, katG, and cyp138 were identified by MEDS as displaying significant evidence of evolving under directional selection influenced by HIV-1 coinfection. All three genes encode proteins that may indirectly interact with human proteins that, in turn, interact functionally with HIV proteins. Unexpectedly, epitope encoding regions were enriched for sites displaying weak evidence of directional selection influenced by HIV-1. Although the low degree of genetic diversity observed in our M. tuberculosis data set means that these results should be interpreted carefully, the effects of HIV-1 on epitope evolution in M. tuberculosis may have implications for the design of M. tuberculosis vaccines that are intended for use in populations with high HIV-1 infection rates.

Validation of CoaBC as a Bactericidal Target in the Coenzyme A Pathway of Mycobacterium tuberculosis

Mycobacterium tuberculosis relies on its own ability to biosynthesize coenzyme A to meet the needs of the myriad enzymatic reactions that depend on this cofactor for activity. As such, the essential pantothenate and coenzyme A biosynthesis pathways have attracted attention as targets for tuberculosis drug development. To identify the optimal step for coenzyme A pathway disruption in M. tuberculosis, we constructed and characterized a panel of conditional knockdown mutants in coenzyme A pathway genes. Here, we report that silencing of coaBC was bactericidal in vitro, whereas silencing of panB, panC, or coaE was bacteriostatic over the same time course. Silencing of coaBC was likewise bactericidal in vivo, whether initiated at infection or during either the acute or chronic stages of infection, confirming that CoaBC is required for M. tuberculosis to grow and persist in mice and arguing against significant CoaBC bypass via transport and assimilation of host-derived pantetheine in this animal model. These results provide convincing genetic validation of CoaBC as a new bactericidal drug target.

Identification of aminopyrimidine-sulfonamides as potent modulators of Wag31-mediated cell elongation in mycobacteria

There is an urgent need to discover new anti-tubercular agents with novel mechanisms of action in order to tackle the scourge of drug-resistant tuberculosis. Here, we report the identification of such a molecule - an AminoPYrimidine-Sulfonamide (APYS1) that has potent, bactericidal activity against M. tuberculosis. Mutations in APYS1-resistant M. tuberculosis mapped exclusively to wag31, a gene that encodes a scaffolding protein thought to orchestrate cell elongation. Recombineering confirmed that a Gln201Arg mutation in Wag31 was sufficient to cause resistance to APYS1, however, neither overexpression nor conditional depletion of wag31 impacted M. tuberculosis susceptibility to this compound. In contrast, expression of the wildtype allele of wag31 in APYS1-resistant M. tuberculosis was dominant and restored susceptibility to APYS1 to wildtype levels. Time-lapse imaging and scanning electron microscopy revealed that APYS1 caused gross malformation of the old pole of M. tuberculosis, with eventual lysis. These effects resembled the morphological changes observed following transcriptional silencing of wag31 in M. tuberculosis. These data show that Wag31 is likely not the direct target of APYS1, but the striking phenotypic similarity between APYS1 exposure and genetic depletion of Wag31 in M. tuberculosis suggests that APYS1 might indirectly affect Wag31 through an as yet unknown mechanism.

The application of tetracyclineregulated gene expression systems in the validation of novel drug targets in Mycobacterium tuberculosis

Although efforts to identify novel therapies for the treatment of tuberculosis have led to the identification of several promising drug candidates, the identification of high-quality hits from conventional whole-cell screens remains disappointingly low. The elucidation of the genome sequence of Mycobacterium tuberculosis (Mtb) facilitated a shift to target-based approaches to drug design but these efforts have proven largely unsuccessful. More recently, regulated gene expression systems that enable dose-dependent modulation of gene expression have been applied in target validation to evaluate the requirement of individual genes for the growth of Mtb both in vitro and in vivo. Notably, these systems can also provide a measure of the extent to which putative targets must be depleted in order to manifest a growth inhibitory phenotype. Additionally, the successful implementation of Mtb strains engineered to under-express specific molecular targets in whole-cell screens has enabled the simultaneous identification of cell-permeant inhibitors with defined mechanisms of action. Here, we review the application of tetracycline-regulated gene expression systems in the validation of novel drug targets in Mtb, highlighting both the strengths and limitations associated with this approach to target validation.

Off label use of devices and drugs in interventional radiology

AIM

To establish how often off-label device and drug use occurs in interventional radiology (IR) in a UK tertiary referral hospital and consider the wider implications for the interventional radiologist.

MATERIALS AND METHODS

Prospective data were collected during interventional procedures for 1 working week in a university hospital. Out-of-hours procedures and procedures outside the department were excluded. Operators were asked to record the drugs and devices used, the indication, and method of use. The instructions for use/summary of product characteristics were then studied for each device/drug used to assess if the use was on or off-label.

RESULTS

During the study period 52 cases were performed and data were available on 26 cases (50%). In 22 of the 26 cases (84%) there was evidence of off-label use of devices or drugs. Off-label use of drugs included treatment of venous malformations with Fibrovein(©) (sodium tetradecyl sulphate), which is licensed for the treatment of varicose veins in the leg, and intra-arterial injection of heparin, which is licensed for intravenous and subcutaneous use. Off-label device use included placing vascular sheaths in the urinary tract, using angiographic catheters to guide wires in the urinary tract, using sheaths for thrombosuction, reshaping of the tip of most guidewires, and using angioplasty balloons to dislodge the arterial plug at fistula thrombectomy.

CONCLUSION

Off-label device and drugs use is common in a UK tertiary hospital IR department and literature suggests this is common in the wider IR community. There are important clinical and legal implications for off-label use for patients and physicians.

The ethics of fish welfare

The topic of fish welfare in the context of commercial fisheries is a difficult one. From traditionally anthropocentric or human-centred perspectives, fishes are simply objects for humans to use as they see fit. When it is argued that anthropocentrism is arbitrary, it may appear that a strong animal rights position is the only recourse, with the result that humans ought not to use animals in the first place, if it is at all possible. It can be argued that both positions fail to view human beings as part of the natural world. If human beings are viewed as part of the world from which they live, then it has to be asked what it means to be respectful of the animals which humans use and from which they live. From this perspective, concern for the welfare of the fishes humans eat is simply what should be expected from humans as good citizens in the community of living creatures.

Angina pectoris is a stronger indicator of diffuse vascular atherosclerosis than intermittent claudication: Framingham study

OBJECTIVE

To compare implications of Angina Pectoris (AP) and Intermittent Claudication (IC) as indicators of clinical atherosclerosis in other vascular territories.

STUDY DESIGN AND SETTING

Prospective cohort study of cardiovascular disease (CVD) in 5,209 men and women of Framingham, MA, aged 28-62 years at enrollment in 1948-1951, who received biennial examinations during the first 36 years of follow-up. Comparative 10-year incidence of subsequent atherosclerotic CVD in participants with IC and AP relative to a reference sample free of CVD was determined.

RESULTS

On follow-up, 95 CVD events occurred in 186 participants with IC and 206 of 413 with AP. After age, sex, and risk-factor adjustment, the proportion acquiring other CVD was 34.0% for IC and 43.4% for AP. Relative to the reference sample, those with IC had a 2.73-fold higher age and sex-adjusted 10-year hazard of CVD (95% CI 2.21, 3.38) and for AP was 3.17 (95% CI 2.73, 3.69). CVD hazard ratios remained more elevated for AP and statistically significant after standard risk factor adjustment. Risk factors accounted for more of the excess CVD risk associated with IC (34.8%) than AP (9.5%).

CONCLUSION

AP is as useful as IC as a hallmark of diffuse atherosclerotic CVD and an indication for comprehensive preventive measures.

Germline mosaicism for a MECP2 mutation in a man with two Rett daughters

Rett syndrome is a severe neurodevelopmental disorder that is caused by mutations in the X-linked gene, methyl-CpG binding protein 2 (MECP2). The majority of cases are sporadic, but rarely germline mosaicism can lead to familial cases. Here, we report the first case where germline mosaicism for a MECP2 mutation has been shown in a man. He has two affected daughters who are half sisters, and both have the c.808delC mutation. We show that this mutation is present at a low level in DNA extracted from the patient's semen. This case has implications for genetic counseling, and pre-natal testing should be offered for the partners of men who have a daughter with Rett syndrome.

People with MECP2 mutation-positive Rett disorder who converse

BACKGROUND

People with useful speech after regression constitute a distinct group of those with mutation-positive Rett disorder, 6% (20/331) reported among mutation-positive people in the British Survey. We aimed to determine the physical, mental and genetic characteristics of this group and to gain insight into their experience of Rett syndrome.

METHODS

Clinical and molecular data for people with Rett, aged 10 or more years at follow-up (the study group, n = 13), with the ability to converse and a MECP2 mutation are presented. They were compared with an age-matched control group (n = 110), who could not converse and had a pathogenic MECP2 mutation.

RESULTS

The study group differed significantly from the control group with regard to their disease severity (P < 0.001); feeding difficulty scores (P < 0.001); health scores (P < 0.001); epilepsy (P < 0.001); head circumference (P < 0.004); age at onset of the regression period (P < 0.001) (six in the study group did not regress) and mutation frequency (C-terminal deletions P = 0.014, R133C P < 0.006). The results indicate that favourable skewing of X-inactivation is only present in a small proportion of mild cases. Speech was fragmented with a soft, breathless quality, and all but two had obviously irregular breathing. One person with an R168X mutation preferred signing to speech. All enjoyed interpersonal contact, showing affection and preferring people to objects, clearly distinguishing the condition from autism. Most were habitually anxious. Music was a source of pleasure and relaxation also providing a valuable educational asset. Even in these most able cases, understanding was severely restricted in most and little initiative was shown.

CONCLUSIONS

While the Rett profile is present in these people they are commonly not classic, and the presence of speech, good head growth and lack of regression may lead to missed diagnoses. A strong association was demonstrated between this milder form of the disease and R133C and C-terminal deletions.

Gross rearrangements of the MECP2 gene are found in both classical and atypical Rett syndrome patients

MECP2 mutations are identifiable in approximately 80% of classic Rett syndrome (RTT), but less frequently in atypical RTT. We recruited 110 patients who fulfilled the diagnostic criteria for Rett syndrome and were referred to Cardiff for molecular analysis, but in whom an MECP2 mutation was not identifiable. Dosage analysis of MECP2 was carried out using multiplex ligation dependent probe amplification or quantitative fluorescent PCR. Large deletions were identified in 37.8% (14/37) of classic and 7.5% (4/53) of atypical RTT patients. Most large deletions contained a breakpoint in the deletion prone region of exon 4. The clinical phenotype was ascertained in all 18 of the deleted cases and in four further cases with large deletions identified in Goettingen. Five patients with large deletions had additional congenital anomalies, which was significantly more than in RTT patients with other MECP2 mutations (2/193; p<0.0001). Quantitative analysis should be included in molecular diagnostic strategies in both classic and atypical RTT.

Analysis of haematopoietic chimaerism by quantitative real-time polymerase chain reaction

Allogeneic bone marrow transplantation (BMT) with marrow ablative conditioning is the treatment of choice for haematopoietic malignancies. The use of nonmyeloablative stem cell transplants has allowed the treatment of patients previously ineligible for BMT because of age or other disease. These reduced conditioning regimes allow the persistence initially of some recipient cells in the blood and bone marrow (haematopoietic chimaerism). Monitoring of the relative proportion of donor and recipient cells is required to assess the success of the procedure, to predict subsequent rejection or impending relapse and to guide the use of donor lymphocyte infusions. We present a quantitative real-time PCR approach for the measurement of haematopoietic chimaerism using the TaqMan. This approach exploits the presence of single-nucleotide polymorphisms (SNPs) to distinguish cells of patient or donor origin. We have designed and validated a panel of seven allele-specific probes to quantify the contribution of patient and donor cells in the haematopoietic population from 12 patient and donor pairs. We have compared the performance of this approach with an existing method and proved it to be superior in both accuracy and sensitivity. The use of more sensitive and accurate techniques permits earlier intervention for improved clinical outcome.

Major resection for chronic pancreatitis in patients with vascular involvement is associated with increased postoperative mortality

Background

The aim was to evaluate the outcome of major resection for chronic pancreatitis in patients with and without vascular involvement.

Methods

Of 250 patients with severe chronic pancreatitis referred between 1996 and 2003, 112 underwent pancreatic resection. The outcome of 17 patients (15·2 per cent) who had major vascular involvement was compared with that of patients without vascular involvement.

Results

The 95 patients without vascular involvement had resections comprising Beger's operation (39 patients), Kausch–Whipple pancreatoduodenectomy (28), total pancreatectomy (25) and left pancreatectomy (three). Twenty-five major vessels were involved in the remaining 17 patients. One or more major veins were occluded and/or compressed producing generalized or segmental portal hypertension, and three patients also had major arterial involvement. Surgery in these patients comprised Beger's operation (eight), total pancreatectomy (five), Kausch–Whipple pancreatoduodenectomy (two) and left pancreatectomy (two). Perioperative mortality rates were significantly different between the groups (two of 95 versus three of 17 respectively; P = 0·024). There were similar and significant improvements in long-term outcomes in both groups.

Conclusion

Resection for severe chronic pancreatitis in patients with vascular complications is hazardous and is associated with an increased mortality rate. Vascular assessment should be included in the routine follow-up of patients with chronic pancreatitis, to enable early identification of those likely to develop vascular involvement and prompt surgical intervention.

Minimally invasive retroperitoneal pancreatic necrosectomy

INTRODUCTION

Open surgery for pancreatic necrosis is associated with considerable morbidity and mortality. We report the results of a recently developed minimally invasive technique that we adopted in 1998.

METHODS

A descriptive explanation of the approach is given together with the results of a retrospective analysis of patients who underwent a minimally invasive retroperitoneal pancreatic necrosectomy (MIRP) between August 1998 and April 2002.

PATIENTS

There were 24 patients with a median (range) age of 61 (29-75) years. The initial median (range) APACHE II score was 8 (2-21). All patients had infected pancreatic necrosis with at least 50% pancreatic necrosis. In three patients it was not possible to complete the first MIRP because of technical reasons.

RESULTS

A total of 88 procedures were performed with a median (range) of 4 (0-8) per patient. Twenty-one (88%) patients developed 36 complications during the course of their illness. Five patients required an additional open procedure: 2 for subsequent distant collections, 2 for bleeding and 1 for persisting sepsis and a distant abscess. Six (25%) patients who had MIRP died. The median (range) post-operative hospital stay was 51 (5-200) days.

CONCLUSIONS

MIRP is a new technique that has shown promising results, and could be preferable to open pancreatic necrosectomy in selected patients. However, unresolved issues remain to be overcome and the exact role of MIRP in the management of pancreatic necrosis has yet to be defined.

Glutamine synthetase in tilapia gastrointestinal tract: zonation, cDNA and induction by cortisol

Glutamine synthetase, an enzyme generally associated with ammonia detoxication in the vertebrate brain and with hepatic nitrogen turnover in mammals, shows substantial activities in the gastrointestinal tract of teleostean fishes. Enzyme activity is highest in the central area of the stomach and reveals a distinct distribution pattern in stomach and along the intestine of tilapia (Oreochromis niloticus), rainbow trout (Oncorhynchus mykiss) and copper rockfish (Sebastes caurinus). In all three species, intestinal activity peaks in the distal region of the intestine. The brain contains the highest titre of the enzyme (46 U g(-1) in tilapia brain versus 15 U g(-1) in tilapia stomach), but because of the relative mass of the stomach, the largest glutamine synthetase pool in tilapia body appears to be localized in the stomach. Activities in white and red muscle are very modest at 0.1% of the brain. Independent of distribution, peak activities of glutamine synthetase in selected areas of tilapia stomach and intestine are significantly (two- to fourfold) increased after a 5-day treatment with an intraperitoneal cortisol deposit. Cortisol also increases glutamine synthetase activity in tilapia liver, white and red muscle, while activities in brain remain unaffected. We cloned and sequenced the predominant transcript of tilapia stomach glutamine synthetase (about 1.9 kb), encoding a 371-amino acid peptide. The open reading frame shows considerable identity with glutamine synthetase in toadfish (92% at peptide level, 87% at nucleotide level), but possesses a longer 3'-untranslated region than the toadfish. The tilapia glutamine synthetase mRNA contains a remnant of a putative mitochondrial leader sequence, but without a conserved second site for initiation of translation. We also find evidence for additional transcripts of glutamine synthetase in tilapia, suggesting multiple genes. Finally, we present evidence for similar abundance of glutamine synthetase transcripts in all regions of rockfish intestine. The physiological significance of the presence of glutamine synthetase in teleostean intestine is discussed.

Association of calpain-10 gene with microvascular function

AIMS/HYPOTHESIS

Genotype could influence vascular function. In some populations, Calpain 10 gene polymorphisms increase susceptibility to diabetes or insulin resistance. Alterations in microvascular function could contribute to insulin resistance. This study investigated whether polymorphisms in the Calpain-10 gene influence microvascular function.

METHODS

Skin maximum microvascular hyperaemia to local heating on the dorsum of the foot (30 min at 43 degrees C) was measured by Laser Doppler Fluximetry in 37 healthy volunteers. All were normoglycaemic according to World Health Organisation criteria, normotensive and not on any medication. Four polymorphisms in the calpain-10 gene were typed: SNP-44, SNP-43, SNP-19, SNP-63. The SNP common to all the described high risk haplotypes is the G-allele at SNP-43. This intron 3 polymorphism appears to influence gene expression. Microvascular function was examined in relation to polymorphisms at this site alone as well as the effects of the known extended high risk haplotypes using the SNP's above.

RESULTS

Maximum microvascular hyperaemia was increased in the 21 subjects with G/G genotypes at SNP-43 compared to the combined group of subjects ( G/ A genotype at SNP-43 ( n=12) + A/ A genotype at SNP-43 ( n=4)), and the minimum microvascular resistance was reduced 49.4 (39.6-94.2) vs 67.5 (39.1-107.3) mmHg/V, p=0.007). Haplotype analysis of the hyperaemic response revealed no significant differences between haplotypes. The two groups did not differ in terms of anthropometric measures, blood pressure, insulin resistance or glucose.

CONCLUSIONS/INTERPRETATION

The polymorphism that confers susceptibility to Type II (non-insulin-dependent) diabetes mellitus in some populations is associated in United Kingdom Caucasians with enhanced microvascular function in the presence of normoglycaemia.

The potential size and duration of an epidemic of bovine spongiform encephalopathy in British sheep

Because there is a theoretical possibility that the British national sheep flock is infected with bovine spongiform encephalopathy (BSE), we examined the extent of a putative epidemic. An age cohort analysis based on numbers of infected cattle, dose responses of cattle and sheep to BSE, levels of exposure to infected feed, and number of BSE-susceptible sheep in the United Kingdom showed that at the putative epidemic peak in 1990, the number of cases of BSE-infected sheep would have ranged from fewer than 10 to about 1500. The model predicts that fewer than 20 clinical cases of BSE in sheep would be expected in 2001 if maternal transmission occurred at a rate of 10%. Although there are large uncertainties in the parameter estimates, all indications are that current prevalence is low; however, a simple model of flock-to-flock BSE transmission shows that horizontal transmission, if it has occurred, could eventually cause a large epidemic.

A national survey of attitudes towards the use of MRI in patients known to have intracranial aneurysm clips

The objective of this study was to determine the attitudes and practice of neuroradiology centres across the UK regarding the use of MRI in patients known to have intracranial aneurysm clips. A postal survey comprising three questions and a comments section was sent to 35 neuroradiology centres across the UK. There were 32 (91%) respondents to the single questionnaire. 16 (50%) respondents said that they would not consider performing MRI on a patient with an intracranial aneurysm clip. Of the remaining 50%, all said that identification of the clip type and assurance of its safety would be needed prior to scanning the patient. The magnetic strength of the system did not appear to affect the decision regarding whether or not to perform MRI on such patients. There was a variation in attitude towards the use of MRI in such patients between different regions. Neuroradiology centres are equally divided in their attitude and practice about whether it is safe to use MR to image a patient known to have an intracranial aneurysm clip. This is most probably due to the conflicting literature, as well as uncertainty about the identification and ferromagnetic properties of individual clips.

Family breast cancer history and mammography: Framingham Offspring Study

The authors examined mammography use according to family cancer history and identified predictors of recent use (<or=2 years). Framingham Offspring Study participants in Framingham, Massachusetts, aged 40-79 years, completed a breast health questionnaire in 1996-1997. The study sample of women included 141 with a first-degree relative with breast cancer, 221 with a mother or sister(s) with other cancers, and 331 with a mother and sister(s) who participate in the Framingham Heart Study and did not report a history of cancer. Stepwise logistic regression analysis was used to identify predictors of recent mammography use. Among women with a family breast cancer history, 98% reported mammography use compared with 95% of other women. Recent mammography use was higher in women with a family breast cancer history (93%) compared with women with a family history of other cancer (80%) and women without a family history of cancer (84%) (p = 0.004). Odds ratios and 95% confidence intervals for significant predictors of recent mammography use were as follows: family history of breast cancer, 3.2 (95% confidence interval (CI): 1.4, 7.7); recent clinical breast examination, 17.4 (95% CI: 9.2, 32.8); and smoking, 0.4 (95% CI: 0.2, 0.7). Mammography use was high among women with a family breast cancer history.

Material properties for modeling traumatic aortic rupture

Traumatic aortic rupture is a significant cause of fatalities in frontal automobile crashes. However, such ruptures are difficult to reproduce experimentally in cadaveric surrogates, and it is difficult to observe dynamic aortic response in situ. So, the aortic injury mechanism or mechanisms remains in dispute. This study is a staged investigation of the physical parameters and mechanisms of human aortic rupture. The investigation includes both experimental study of local and global viscoelastic properties and failure properties of aortas using aortic tissue samples, excised aortas in vitro, and whole human aortas in situ in cadaver thoraxes. This study is the first phase in a staged programme to develop a finite element computer model of aorta injury to examine the mechanisms of aorta injury in automobile crashes. The high-rate local biaxial properties of porcine aorta tissue are determined from samples taken from the isthmus region, the most common area of failure in traumatic aorta injury. Using porcine aortas, similar in structure and physical characteristics to human aortic tissue, biaxial oscillatory response is determined at large strains and high strain rates. From this data, a hyperelastic material model with a failure threshold is developed that is in good agreement with local property data determined from oscillatory tests at 20 Hz and 65 Hz. Further, whole aorta tests are performed using pressure application with aortic pressure time histories similar in onset rate to those seen in cadaveric sled testing. These tests establish the ultimate stretch ratio and strain to failure for human aorta specimens. The specimens show no significant difference in response between the in situ tests and the in vitro tests. This indicates either that the internal thoracic boundary conditions may not be important in the stress and strain level of aorta failure or that the number of in situ tests (3) was too small to establish a difference. A Weibull survival analysis of the whole aorta failure tests shows significant dependence of aortic ultimate stretch ratio on age. A 50% risk of failure is 852 kPa in the circumferential direction and 426 kPa in the longitudinal direction. For pressure, the 50% risk of failure for all the tests is approximately 101 kPa. This increases to greater than 120 kPa for subjects below 68 years.

Heritability of longitudinal change in lung function. The Framingham study

There have been multiple reports of heritability of lung function in cross-sectional analysis, but no prior reports of heritability of rate of change in lung function. We examined heritability of rate of change of lung function in families participating in the Framingham Heart Study. Spirometric measures from two time points were used to calculate annualized rate of change in FEV(1), FVC, and FEV(1)/FVC ratio, adjusting for the effects of age, height, and weight using multiple linear regression models. Standardized residuals from these models were used as phenotypic variables in variance components analysis to assess effects of smoking and heritable factors on rate of change in lung function. Heritable factors explained a modest proportion of the population variance, with heritability estimates for change in FEV(1), FVC, and ratio of 0.05, 0.18, and 0.13, respectively. Restricting the analysis to subjects concordant for smoking status during the interval over which lung function was measured, the heritability estimates increased to 0.18, 0.39, and 0.14, respectively, among interim smokers. These data suggest that in middle-aged and older persons in the general population, genetic factors contribute modestly to the overall population variance in rate of lung function decline, and further suggest the importance of gene-environment interactions.

Impact of high-normal blood pressure on the risk of cardiovascular disease

BACKGROUND

Information is limited regarding the absolute and relative risk of cardiovascular disease in persons with high-normal blood pressure (systolic pressure of 130 to 139 mm Hg, diastolic pressure of 85 to 89 mm Hg, or both).

METHODS

We investigated the association between blood-pressure category at base line and the incidence of cardiovascular disease on follow-up among 6859 participants in the Framingham Heart Study who were initially free of hypertension and cardiovascular disease.

RESULTS

A stepwise increase in cardiovascular event rates was noted in persons with higher baseline blood-pressure categories. The 10-year cumulative incidence of cardiovascular disease in subjects 35 to 64 years of age who had high-normal blood pressure was 4 percent (95 percent confidence interval, 2 to 5 percent) for women and 8 percent (95 percent confidence interval, 6 to 10 percent) for men; in older subjects (those 65 to 90 years old), the incidence was 18 percent (95 percent confidence interval, 12 to 23 percent) for women and 25 percent (95 percent confidence interval, 17 to 34 percent) for men. As compared with optimal blood pressure, high-normal blood pressure was associated with a risk-factor-adjusted hazard ratio for cardiovascular disease of 2.5 (95 percent confidence interval, 1.6 to 4.1) in women and 1.6 (95 percent confidence interval, 1.1 to 2.2) in men.

CONCLUSIONS

High-normal blood pressure is associated with an increased risk of cardiovascular disease. Our findings emphasize the need to determine whether lowering high-normal blood pressure can reduce the risk of cardiovascular disease.

Echocardiographic features of the right heart in sleep-disordered breathing: the Framingham Heart Study

The effect of sleep-disordered breathing (SDB) on right heart structure and function is controversial. Studies of patients referred for evaluation of possible sleep apnea have yielded conflicting results, and the impact of SDB on the right heart has not been investigated in the general population. We examined the echocardiographic features of subjects with SDB at the Framingham Heart Study site of the Sleep Heart Health Study. Of 1,001 polysomnography subjects, 90 with SDB defined as a respiratory disturbance index (RDI) score > 90th percentile (mean RDI = 42) were compared with 90 low-RDI subjects (mean RDI = 5) matched for age, sex, and body mass index. Right heart measurements, made without knowledge of clinical status, were compared between groups. The majority of the subjects were male (74%). After multivariable adjustment, right ventricle (RV) wall thickness was significantly greater (p = 0.005) in subjects with SDB (0.78 +/- 0.02 cm) than in the low-RDI subjects (0.68 +/- 0.02 cm). Right atrial dimensions, RV dimensions, and RV systolic function were not found to be significantly different between subjects with SDB and the low-RDI subjects. We conclude that in this community-based study of SDB and right heart echocardiographic features, RV wall thickness was increased in subjects with SDB. Whether the RV hypertrophy observed in persons with SDB is associated with increased morbidity and mortality remains unknown.

beta-cell genes and diabetes: molecular and clinical characterization of mutations in transcription factors

beta-Cell transcription factor genes are important in the pathophysiology of the beta-cell, with mutations in hepatocyte nuclear factor (HNF)-1alpha, HNF-4alpha, insulin promoter factor (IPF)-1, HNF-1beta, and NeuroD1/BETA2, all resulting in early-onset type 2 diabetes. We assessed the relative contribution of these genes to early-onset type 2 diabetes using linkage and sequencing analysis in a cohort of 101 families (95% U.K. Caucasian). The relative distribution of the 90 families fitting maturity-onset diabetes of the young (MODY) criteria was 63% HNF-1alpha, 2% HNF-4alpha, 0% IPF-1, 1% HNF-1beta, 0% NeuroD1/ BETA2, and 20% glucokinase. We report the molecular genetic and clinical characteristics of these patients including 29 new families and 8 novel HNF-1alpha gene mutations. Mutations in the transactivation domain are more likely to be protein truncating rather than result in amino acid substitutions, suggesting that a relatively severe disruption of this domain is necessary to result in diabetes. Mutations in the different transcription factors result in clinical heterogeneity. IPF-1 mutations are associated with a higher age at diagnosis (42.7 years) than HNF-1alpha (20.4 years), HNF-1beta (24.2 years), or HNF-4alpha (26.3 years) gene mutations. Subjects with HNF-1beta mutations, in contrast to the other transcription factors, frequently present with renal disease. A comparison of age at diagnosis between subjects with different types and locations of HNF-1alpha mutations did not reveal genotype-phenotype correlations. In conclusion, mutations in transcription factors expressed in the beta-cell are the major cause of MODY, and the phenotype clearly varies with the gene that is mutated. There is little evidence to indicate that different mutations within the same gene have different phenotypes.

Thrombosed double inferior vena cava mimicking paraaortic lymphadenopathy

A case is presented of thrombosis of an anomalous left-sided duplication of the inferior vena cava misinterpreted on CT as lymphadenopathy or other retroperitoneal mass. Recognition of this anomaly is important in reaching the correct diagnosis in such cases. The diagnosis by imaging methods is described as well as their pitfalls.

Differential control of systolic and diastolic blood pressure : factors associated with lack of blood pressure control in the community

Data from the Third National Health and Nutrition Examination Survey, phase 2 (1991 to 1994), indicate that among hypertensive individuals in the United States, 53.6% are treated and only 27.4% are controlled to goal levels. We sought to determine whether poor hypertension control is due to lack of systolic or diastolic blood pressure control, or both. We studied Framingham Heart Study participants examined between 1990 and 1995 and determined rates of control to systolic goal (<140 mm Hg), diastolic goal (<90 mm Hg), or both (systolic <140 and diastolic <90 mm Hg). Of 1959 hypertensive subjects (mean age 66 years, 54% women), 32.7% were controlled to systolic goal, 82.9% were controlled to diastolic goal, and only 29.0% were controlled to both. Among the 1189 subjects who were receiving antihypertensive therapy (60.7% of all hypertensive subjects), 49.0% were controlled to systolic goal, 89.7% were controlled to diastolic goal, and only 47.8% were controlled to both. Thus, poor systolic blood pressure control was overwhelmingly responsible for poor rates of overall control to goal. Covariates associated with lack of systolic control in treated subjects included older age (OR for age 61 to 75 years, 2.43, 95% CI 1.79 to 3.29; OR for age >75 years, 4.34, 95% CI 3.10 to 6.09), left ventricular hypertrophy (OR 1.63, 95% CI 1.04 to 2.54), and obesity (OR for body mass index >/=30 versus <25 kg/m(2), 1.49, 95% CI 1.08 to 2.06). In this community-based sample of middle-aged and older subjects, overall rates of hypertension control were remarkably similar to those in the Third National Health and Nutrition Examination Survey. Poor blood pressure control was overwhelmingly due to lack of systolic control, even among treated subjects. Therefore, clinicians and policymakers should place greater emphasis on the achievement of goal systolic levels in all hypertensive patients, especially those who are older or obese or have target organ damage.

The ASK Model

Professional nurses are expected to read and evaluate nursing research. Many nurses' report feeling intimated by research studies. The Applicability, Science, Knowledge Model offers the basics needed to quickly review and grasp the potential clinical significance of a journal study. Using a research report previously published in the Journal of Trauma Nursing, the authors demonstrate the critique process. Key points for critical understanding and guidelines for application to practice are presented.

Extensive soft tissue uptake of 99Tcm methylene diphosphonate in a patient with multiple myeloma

Bone scintigraphy is not usually performed in multiple myeloma (MM), as marrow deposits characteristically show no tracer uptake. However, metastatic bone disease often mimics MM both clinically and biochemically, resulting in a substantial number of MM patients undergoing bone scintigraphy. Variable appearances in these cases have been reported, ranging from normal to a superscan, the latter a result of massive tracer uptake within bone. Soft tissue uptake has been documented, often when MM is complicated by secondary amyloidosis. This usually results in mainly solid organ uptake of tracer. We report a case of MM where massive soft tissue uptake occurred, primarily within muscles, with very little isotope elsewhere.

Confirmation of linkage of Duane's syndrome and refinement of the disease locus to an 8.8-cM interval on chromosome 2q31

Duane's syndrome is a congenital abnormality of eye movement, which may be inherited as an autosomal dominant trait but usually occurs sporadically. Genetic mapping in a Mexican family has recently identified a locus for Duane's syndrome within a 17.8-cM region of chromosome 2q31. The region was flanked by the microsatellite markers D2S2330 and D2S364. We performed linkage and haplotype analysis in a four-generation UK family with autosomal dominant transmission of Duane's syndrome. Linkage to 2q31 was confirmed with a maximum logarithm of differences (lod) score of 3.3 at theta = 0. The genetic interval was reduced to an 8.8-cM region between markers D2S326 and D2S364 that includes the candidate homeobox D gene cluster.

Is vaginal delivery preferable to elective cesarean delivery in fetuses with a known ventral wall defect?

OBJECTIVE

We sought to test the hypothesis that vaginal delivery compared with elective cesarean delivery results in improved neonatal outcome in fetuses with a known isolated ventral wall defect.

STUDY DESIGN

We performed a retrospective chart review.

RESULTS

Between 1989 and 1999, we identified 102 infants with a confirmed antenatal diagnosis of an isolated ventral wall defect with either the diagnosis of an omphalocele or gastroschisis. Sixty-six infants were delivered by cesarean and 36 were delivered vaginally. There were no significant demographic differences between the study groups or between the two sites except that one center (Cincinnati) usually delivered these fetuses by cesarean whereas the other (Louisville) usually delivered such fetuses vaginally. Overall, there were a greater number of infants with gastroschisis than omphalocele (gastroschisis, n = 71; omphalocele, n = 31). After we controlled for primary versus staged closure of ventral wall defect and gestational age at delivery; the medians and interquartile ranges for cesarean and vaginal delivery were 39 (25, 63) days versus 42 (26, 75) days, respectively (P =.32), for neonatal length of stay and 13 (9, 18) days versus 13 (9, 26) days, respectively (P =.16), for days to enteral feeding. After we controlled for the size of the defect and the amount of bowel resected, the odds of primary closure given a vaginal delivery was about half that given a cesarean delivery (odds ratio, 0.56; 95% confidence interval, 0.18-1. 69), but this was not statistically significant. There was no statistically significant difference in the rates of neonatal death (2 [3%] vs 2 [6%]; P =.61) and neonatal sepsis (2 [3%] vs 4 [11%]; P =.18) for cesarean versus vaginal delivery. Maternal length of stay after delivery was found to be 1 day less after vaginal delivery [vaginal, 2 (2, 2) days; cesarean, 3 (2, 3) days; P =.0001]. There were 5 instances of maternal complications, and all 5 pregnancies were delivered by cesarean (P =.16).

CONCLUSION

Fetuses with an antenatal diagnosis of an isolated ventral wall defect may safely be delivered vaginally, and cesarean delivery should be performed for obstetric indications only.

Antibacterial efficacy of gentamicin encapsulated in pH-sensitive liposomes against an in vivo Salmonella enterica serovar typhimurium intracellular infection model

Encapsulation of gentamicin in liposomes can be used to achieve intracellular delivery and broaden the clinical utility of this drug. We have previously described a novel, rationally designed, pH-sensitive liposomal carrier for gentamicin that has superior in vitro efficacy against intracellular infections compared to the efficacies of both free gentamicin and non-pH-sensitive liposomal controls. This liposomal carrier demonstrated pH-sensitive fusion that was dependent on the presence of unsaturated phosphatidylethanolamine (PE) and the pH-sensitive lipid N-succinyldioleoyl-PE. The pharmacokinetics and biodistribution of the free and liposomal gentamicin were examined in mice bearing a systemic Salmonella enterica serovar Typhimurium infection. Encapsulation of gentamicin in pH-sensitive liposomes significantly increased the concentrations of the drug in plasma compared to those of free gentamicin. Furthermore, the levels of accumulation of drug in the infected liver and spleen were increased by 153- and 437-fold, respectively, as a result of liposomal encapsulation. The increased accumulation of gentamicin in the liver and spleen effected by liposomal delivery was associated with 10(4)-fold greater antibacterial activity than that associated with free gentamicin in a murine salmonellosis model. These pH-sensitive liposomal antibiotic carriers with enhanced in vitro activity could be used to improve both in vivo intracellular drug delivery and biological activity.

Association of blood pressure with fibrinolytic potential in the Framingham offspring population

BACKGROUND

Hypertension is an established risk factor for acute coronary events. Because fibrinolytic and hemostatic factors are also associated with cardiovascular disease, we examined the relations of systolic and diastolic blood pressures (SBP and DBP) to levels of plasminogen activator inhibitor antigen, tissue plasminogen activator antigen, fibrinogen, factor VII, von Willebrand factor, fibrinogen, and plasma viscosity in subjects of the Framingham Offspring Study.

METHODS AND RESULTS

We studied 1193 men and 1459 women after the exclusion of subjects with known cardiovascular disease and those receiving anticoagulant or antihypertensive therapy. Linear regression models were used to evaluate SBP and DBP as predictors of fibrinolytic and hemostatic factor levels in separate sex models, with adjustment for age, body mass index, smoking, diabetes, total cholesterol, HDL, triglycerides, alcohol intake, and estrogen use (in women). In both sexes, levels of plasminogen activator inhibitor and tissue plasminogen activator antigen were positively related to SBP and DBP (P<0.001). Plasma viscosity was positively related to SBP (P=0.008) and DBP (P=0.001) in women only. There was no association between SBP or DBP and fibrinogen, factor VII, or von Willebrand factor in either sex.

CONCLUSIONS

These data suggest that impaired fibrinolysis may play an important role in the pathogenesis of cardiovascular disease in hypertensive patients.

The radiological appearances of tuberous sclerosis

Tuberous sclerosis is an autosomal dominant disorder often associated with a chromosome 9 abnormality, although up to 60% of cases occur spontaneously. The incidence of the disorder is between 1/100,000 and 1/10,000, and it leads to multiple organ and skeletal abnormalities. The classical triad of epilepsy, mental retardation and adenoma sebaceum defines the syndrome clinically. Other cutaneous associations include shagreen patches, ash leaf-shaped areas of depigmentation, subungual fibromas and café-au-lait spots. This review describes the commoner radiological manifestations of the syndrome, and briefly mentions the rarer associations that have been reported to date.

Parent-offspring trios: a resource to facilitate the identification of type 2 diabetes genes

The transmission disequilibrium test with use of trios (an affected proband with both parents) is a robust method for assessing the role of gene variants in disease that avoids the problem of population stratification that may confound conventional case/control studies and allows the detection of parent-of-origin effects. Trios have played a major role in defining genes in a number of polygenic conditions, including type 1 diabetes. We assessed the prevalence, clinical characteristics, and suitability for defining type 2 susceptibility genes of European type 2 diabetes trios. In a Caucasian population in the U.K., only 2.5% of type 2 patients had both parents alive. Using a nationwide strategy, we collected 182 trios defined by strict clinical criteria. Immunological and genetic testing resulted in the exclusion of 25 trios as a result of latent autoimmune diabetes (n = 13), inconsistent family relationships (n = 7), and maternally inherited diabetes and deafness (n = 5). The 157 remaining probands had similar treatment requirements to familial type 2 diabetic subjects but presented at a younger age, were more obese, and more frequently had affected parents. Using this resource, we have not found any evidence for linkage disequilibrium between type 2 diabetes and the glucokinase gene markers GCK1 and GCK2 and the chromosome 20 marker D20S197. We conclude that European type 2 diabetes trios are difficult to collect but provide an important additional approach to dissecting the genetics of type 2 diabetes.

Cardiovascular disease and mortality in a community-based cohort with mild renal insufficiency

Cardiovascular disease and mortality in a community-based cohort with mild renal insufficiency.

BACKGROUND

Little is known about the prevalence of cardiovascular disease (CVD) and associated risk factors in individuals with mild renal insufficiency (RI). Furthermore, the long-term outcomes associated with mild RI in the community have not been described.

METHODS

Serum creatinine (SCr) was measured in 6233 adult participants of the Framingham Heart Study (mean age 54 years, 54% women). Mild RI was defined as SCr 136 to 265 micromol/liter (1.5 to 3.0 mg/dl) in men and 120 to 265 micromol/liter (1.4 to 3.0 mg/dl) in women. The lower limits for mild RI were defined by the sex-specific 95th percentile SCr values in a healthy subgroup of our sample. The upper limit for mild RI was chosen to exclude those subjects with more advanced renal failure. Cox proportional hazards analyses were used to determine the relationship of baseline RI to CVD and all-cause mortality.

RESULTS

At baseline, 8.7% of men (N = 246) and 8.0% of women (N = 270) had mild RI. Nineteen percent of the subjects with mild RI had prevalent CVD. During 15 years of follow-up, there were 1000 CVD events and 1406 deaths. In women, mild RI was not associated with increased risk for CVD events [hazards ratio (HR) 1.04, 95% CI, 0.79 to 1.37] or all-cause mortality (HR 1.08, 95% CI, 0.87 to 1.34). In men, mild RI showed no significant associations with CVD events (HR 1.17, 95% CI, 0.88 to 1.57), but it was associated with all-cause mortality in age-adjusted (HR 1.42, 95% CI, 1.12 to 1.79) and multivariable adjusted (HR 1.31, 95% CI, 1.02 to 1.67) analyses.

CONCLUSION

Mild RI in the community is common and is associated with a high prevalence of CVD. The association of RI with risk for adverse outcomes is strongly related to coexisting CVD and CVD risk factors.