Risk factors associated with increased prevalence of abdominal aortic aneurysm in women.

BACKGROUND: Four randomized trials of men aged 65-80 years showed that aneurysm-related mortality was reduced by 40 per cent by ultrasound screening. Screening is considered economically viable when the prevalence of abdominal aortic aneurysm (AAA) is 1·0 per cent or higher. This is not the case for women, in whom the prevalence of AAA is less than 1 per cent. The aim of the present investigation was to determine the prevalence of AAA 3·0 cm or larger in women screened with ultrasound imaging, the risk factors associated with AAA in this population, and whether high-risk groups can be identified with an AAA prevalence of 1 per cent or greater. METHODS: Demographic data and risk factors were collected from the first 50 000 women who attended for private cardiovascular screening in the UK. Tests included ultrasound screening for AAA, ankle : brachial pressure index (ABPI), carotid duplex imaging for carotid atherosclerosis, and electrocardiography for atrial fibrillation. RESULTS: AAA was detected in 82 of 50 000 women screened; these aneurysms were rare below the age of 66 years (7 of 24 499). In the 66-85-years age group there were 72 AAAs in 25 170 women (0·29 per cent). Univariable analysis demonstrated that a history of stroke/transient ischaemic attack (TIA), hypertension, smoking, atrial fibrillation, ABPI of less than 0·9 and internal carotid artery stenosis of at least 50 per cent were associated with an increased prevalence of AAA (P < 0·001). In multivariable linear logistic regression of risk factors, age 76 years or more, history of stroke/TIA, hypertension and smoking were independent predictors of AAA. This model had an area under the receiver operating characteristic (ROC) curve (AUC) of 0·711 (95 per cent c.i. 0·649 to 0·772) and could identify 2235 women who had 22 AAAs (prevalence 0·98 per cent). By adding ABPI, atrial fibrillation and carotid stenosis, the prediction improved to an AUC of 0·775 (0·724 to 0·826). This model could identify 3701 women who had 58 AAAs (prevalence 1·57 per cent). CONCLUSION: This report should stimulate consideration of a targeted AAA screening programme for women aged over 65 years.

Joint recommendations for reporting carotid ultrasound investigations in the United Kingdom.

At present in the United Kingdom a number of different criteria are used to grade disease in carotid ultrasound investigations. One main cause of this has been the difference in the method of grading angiograms used in the NASCET and ECST large carotid surgery trials. It is desirable that all centres reporting carotid ultrasound investigations report to the same standard. This paper presents recommendations for the reporting of ultrasound investigations of the extra cranial arteries produced by a Joint Working Group formed between the Vascular Society of Great Britain and Ireland, and the Society for Vascular Technology of Great Britain and Ireland. The recommended criteria are based on the NASCET method of grading carotid bulb disease. Key recommendations include recording peak systolic velocity (PSV) and end-diastolic velocity (EDV) in both internal and distal common carotid arteries; measuring all velocities at a Doppler angle of 45-60 degrees; the use of internal carotid PSV of >1.25 ms(-1) and >2.3 ms(-1) and a Peak Systolic Velocity Ratio of >2 and >4 to indicate >50% and >70% stenosis respectively; and the use of the St Mary's Ratio to grade >50% stenoses in deciles. General recommendations are also given for the acquisition, interpretation and reporting of the data.

Decreased skeletal muscle mitochondrial DNA in patients treated with high-dose simvastatin.

Statins are generally well tolerated, but can cause myopathy and have been associated with mitochondrial abnormalities. The aim of this study was to determine whether muscle mitochondrial DNA (mtDNA) levels are altered during statin therapy. We retrospectively quantified mtDNA in 86 skeletal muscle biopsy specimens collected as part of a previously published clinical trial of high-dose simvastatin or atorvastatin versus placebo.

PKA, PKC, and AKAP localization in and around the neuromuscular junction.

BACKGROUND: One mechanism that directs the action of the second messengers, cAMP and diacylglycerol, is the compartmentalization of protein kinase A (PKA) and protein kinase C (PKC). A-kinase anchoring proteins (AKAPs) can recruit both enzymes to specific subcellular locations via interactions with the various isoforms of each family of kinases. We found previously that a new class of AKAPs, dual-specific AKAPs, denoted D-AKAP1 and D-AKAP2, bind to RIalpha in addition to the RII subunits. RESULTS: Immunohistochemistry and confocal microscopy were used here to determine that D-AKAP1 colocalizes with RIalpha at the postsynaptic membrane of the vertebrate neuromuscular junction (NMJ) and the adjacent muscle, but not in the presynaptic region. The labeling pattern for RIalpha and D-AKAP1 overlapped with mitochondrial staining in the muscle fibers, consistent with our previous work showing D-AKAP1 association with mitochondria in cultured cells. The immunoreactivity of D-AKAP2 was distinct from that of D-AKAP1. We also report here that even though the PKA type II subunits (RIIalpha and RIIbeta) are localized at the NMJ, their patterns are distinctive and differ from the other R and D-AKAP patterns examined. PKCbeta appeared to colocalize with the AKAP, gravin, at the postsynaptic membrane. CONCLUSIONS: The kinases and AKAPs investigated have distinct patterns of colocalization, which suggest a complex arrangement of signaling micro-environments. Because the labeling patterns for RIalpha and D-AKAP 1 are similar in the muscle fibers and at the postsynaptic membrane, it may be that this AKAP anchors RIalpha in these regions. Likewise, gravin may be an anchor of PKCbeta at the NMJ.

Oxidative modification and inactivation of the proteasome during coronary occlusion/reperfusion.

Restoration of blood flow to ischemic myocardial tissue results in an increase in the production of oxygen radicals. Highly reactive, free radical species have the potential to damage cellular components. Clearly, maintenance of cellular viability is dependent, in part, on the removal of altered protein. The proteasome is a major intracellular proteolytic system which degrades oxidized and ubiquitinated forms of protein. Utilizing an in vivo rat model, we demonstrate that coronary occlusion/reperfusion resulted in declines in chymotrypsin-like, peptidylglutamyl-peptide hydrolase, and trypsin-like activities of the proteasome as assayed in cytosolic extracts. Analysis of purified 20 S proteasome revealed that declines in peptidase activities were accompanied by oxidative modification of the protein. We provide conclusive evidence that, upon coronary occlusion/reperfusion, the lipid peroxidation product 4-hydroxy-2-nonenal selectively modifies 20 S proteasome alpha-like subunits iota, C3, and an isoform of XAPC7. Occlusion/reperfusion-induced declines in trypsin-like activity were largely preserved upon proteasome purification. In contrast, loss in chymotrypsin-like and peptidylglutamyl-peptide hydrolase activities observed in cytosolic extracts were not evident upon purification. Thus, decreases in proteasome activity are likely due to both direct oxidative modification of the enzyme and inhibition of fluorogenic peptide hydrolysis by endogenous cytosolic inhibitory protein(s) and/or substrate(s). Along with inhibition of the proteasome, increases in cytosolic levels of oxidized and ubiquitinated protein(s) were observed. Taken together, our findings provide insight into potential mechanisms of coronary occlusion/reperfusion-induced proteasome inactivation and cellular consequences of these events.

Three-dimensional endoanal sonography in assessing anal canal injury.

BACKGROUND: Instrument design limits endosonography of the anal canal to the axial plane, with no capability for longitudinal imaging or measurement. Using three-dimensional reconstructions, the relationship between the radial and linear extent of an anal sphincter tear has been explored, and sex differences in anal canal and sphincter length have been established. METHODS: Three-dimensional reconstructions were performed in 20 controls and 24 patients with faecal incontinence found to have 25 external and five internal sphincter defects. The radial and linear extent of any sphincter tear was measured. In controls the length of the sphincters was compared with the total anal canal length, and the maximum and mean internal sphincter thickness was compared. RESULTS: The radial angle of an internal or external sphincter defect was significantly related to its length (R2 = 96.8 per cent and R2 = 84.4 per cent respectively; both P < 0.001). The anal canal was longer in men than in women (mean(s.d.) 32.6(5.3) versus 25.1(3.4) mm; P < 0.001). The internal anal sphincter was also longer in men (25.6(6.3) versus 19.8(4.0) mm; P < 0.02), but the mean internal sphincter length as a percentage of total anal canal length did not differ (78.3 versus 78.7 per cent; P not significant). The anterior external anal sphincter was longer in men than in women (32.6(5.3) versus 15.3(2.8) mm; P < 0.001), and formed a greater percentage of total anal canal length (100 versus 62.9 per cent; P < 0.001). CONCLUSION: Multiplanar imaging has revealed a direct relationship between the length of a sphincter tear and its radial extent as shown on axial scanning. Marked sex differences in sphincter configuration have been demonstrated. In women the shorter anterior sphincter length highlights the risk of complete sphincter disruption with extensive tears.

The effect of partial extraction of troponin C on the elementary steps of the cross-bridge cycle in rabbit psoas muscle fibers.

The elementary steps of the cross-bridge cycle in which troponin C (TnC) was partially extracted were investigated by sinusoidal analysis in rabbit psoas muscle fibers. The effects of MgATP and phosphate on the rate constants of exponential processes were studied at 200 mM ionic strength, pCa 4.20, pH 7.00, and at 20 degrees C. The results were analyzed with the following cross-bridge scheme: [formula: see text] where A is actin, M is myosin, S is MgATP, D is MgADP, and P is phosphate (Pi). When TnC was extracted so that the average remaining tension was 11% (range 8-15%), K1 (MgATP association constant) increased to 7x, k2 (rate constant of cross-bridge detachment) increased to 1.55x, k-2 (reversal of detachment) decreased to 0.27x, and K2 (= k2/k-2: equilibrium constant of cross-bridge detachment) increased to 6.6x, k4 (rate constant of force generation) decreased to 0.4x, k-4 (reversal of force generation) increased to 2x, K4 (= k4/k-4) decreased to 0.17x, and K5 (Pi association constant) did not change. The activation factor alpha, which represents the fraction of cross-bridges participating in the cycling, decreased from 1 to 0.14 with TnC extraction. The fact that K1 increased with TnC extraction implies that the condition of the thin filament modifies the contour of the substrate binding site on the myosin head and is consistent with the Fenn effect. The fact that alpha decreased to 0.14 is consistent with the steric blocking mechanism (recruitment hypothesis) and indicates that some of the cross-bridges disappear from the active cycling pool. The fact that the equilibrium constants changed is consistent with the cooperative activation mechanism (graded activation hypothesis) among thin-filament regulatory units that consist of troponin (TnC, Tnl, TnT), tropomyosin, and seven actin molecules, and possibly include cross-bridges.

Stage- and lineage-specific expression of the HOXA10 homeobox gene in normal and leukemic hematopoietic cells.

There is growing evidence that the HOX homeobox-containing transcription factors are differentially expressed during hematopoiesis. We have previously demonstrated that the HOXA10 gene is expressed in unfractionated normal marrow and in immortalized leukemic cell lines with myelomonocytic features, but not in cell lines with lymphoid or erythroid features. To gain insights into the patterns of activation of this gene during hematopoietic differentiation, we have examined HOXA10 expression in CD34+ and CD34- subfractions of normal marrow and normal peripheral blood, as well as samples from patients with a variety of acute and chronic leukemias. HOXA10 is strongly expressed in CD34+ normal marrow cells, markedly downregulated in CD34- marrow cells, and inactive in mature neutrophils, monocytes, and lymphocytes. HOXA10 is expressed in all types of acute myelogenous leukemia (AML) with the notable exception of acute promyelocytic leukemia (AML-M3). HOXA10 message is observed in chronic myelogenous leukemia (CML) but appears to be reduced in accelerated phase and blast crisis, particularly lymphoid blast crisis. With rare exception, HOXA10 expression is not observed in samples of acute or chronic lymphoid leukemias. Normal marrow and patient samples appear to contain a single transcript which encodes a full-length homeobox-containing protein, while immortalized cell lines contain an additional alternatively spliced transcript. These studies indicate that HOXA10 expression is restricted to early stages of myeloid differentiation.

Activity of D-glucarate analogues: synergistic antiproliferative effects with retinoid in cultured human mammary tumor cells appear to specifically require the D-glucarate structure.

D-Glucarate has shown modest chemopreventive and synergistic chemopreventive effects with retinoids in a number of tumor models as well as a similar antiproliferative effect in MCF-7 human tumor cells in culture. It has been postulated that D-glucarate exerts some of its effects by equilibrium conversion to D-glucarolactone, a potent beta-glucuronidase inhibitor. In the present study, D-glucarate and a number of its analogues, including D-glucarolactone, were evaluated as antiproliferatives in the MCF-7 model with and without added retinoid. Results suggest that the effects of glucarate are reasonably specific for its structure and may not require conversion to glucarolactone.

Basis for the anti-tumor and chemopreventive activities of glucarate and the glucarate:retinoid combination.

The biochemical basis for the cancer chemopreventive and anti-cancer activities of glucarate, retinoids (13-cis-retinoic acid, hydroxyphenyl retinamide) and their synergistic combination, has been evaluated. Neither alone nor in combination did these agents affect the level in the rat, of enzymes which are (a) known to correlate with reduced risk of carcinogenesis (detoxification enzyme, catalase, glutathione reductase) nor (b) enzymes which correlate with increased risk of carcinogenesis (beta-glucuronidase, xanthine oxidase, glucose-6-phosphate dehydrogenase). Retinoids, but neither glucarate nor its lactone inhibited free radical-induced lipid peroxidation. Both agents alone and synergistically in combination, raise cellular cAMP levels, repress protein kinase C and more generally inhibited DNA synthesis.

Monitoring hemangioblastoma tumor burden using plasma erythropoietin levels.

We report a 39-year-old female patient with a hepatic hemangioblastoma, polycythemia and elevated plasma erythropoietin (Epo) levels. Following orthotopic liver transplantation (OLTx), her plasma Epo levels and hematocrit normalized but began to rise several months later. This rise correlated with the appearance of multiple lung metastases. The tumor was implicated as the source of excess Epo production using Northern analysis of a resected metastatic lung nodule. Based on our results, the measurement of plasma Epo levels in patients with Epo secreting tumors could be of general utility in assessing tumor burden.

Analysis of splice junctions and in vitro and in vivo translation potential of the small, abundant B19 parvovirus RNAs.

Two parvovirus B19 cDNA libraries have been constructed; one from COS-7 cells transfected with a B19/pSVOd hybrid vector and the other from B19-infected human erythroid leukemic cells. We have used these libraries to investigate the expression of the abundant classes of polyadenylated B19 RNAs; the 700- and 800-nt class which terminates in the middle of the genome and the 500- and 600-nt class which contains an ORF from the extreme right-hand end of the genome. The 700- and 800-nt RNA species were not found in the COS cell library, suggesting that a variant polyadenylation signal (ATTAAA or AATAAC) in the middle of the genome is not efficiently recognized in these cells. In contrast, the 700- and 800-nt class was highly represented in the human library, confirming the use of this variant polyadenylation signal in the normal host cell of the virus. In COS cells the middle exon of the 500- and 600-nt class of RNA exhibited variability in both splice donor and acceptor sites. However, in human cells there were only two splice acceptor sites nt 1910 and 2030, and a single splice donor site nt 2183 for this exon. Antisera, prepared against a peptide derived from the 94-aa potential protein encoded by the 500- and 600-nt class of RNA, recognized, on a Western blot, a polypeptide of approximately 11 kDa that was translated in vitro from these cDNAs and in vivo in pSVOd/B19 transfected COS cells. Immunoprecipitation revealed that two proteins were made from this ORF, suggesting the use of internal translation initiation site(s). Another antisera, raised against a second peptide corresponding to an antigenic region of the potential protein encoded by the 700- and 800-nt class of RNA, failed to detect a 15-kDa protein by Western blotting or immunoprecipitation of labeled proteins both in vitro and in vivo in COS cells.

Impact of duplex scanning on carotid endarterectomy.

Duplex ultrasound permits safe and accurate assessment of the extracranial vasculature. This paper reports the change in patterns of referral to a specialized vascular unit following its introduction; increased referrals were seen in all specialties except neurology. A widely available and reliable duplex service has revealed more extracranial vascular disease than was previously recognized, and has increased referrals for carotid endarterectomy, thereby increasing surgical workload.

Digoxin-like immunoreactivity, displacement of ouabain and inhibition of Na+/K+ ATPase by four steroids known to be increased in essential hypertension.

An endogenous digoxin-like immunoreactive substance(s) (DLIS, "endoxin") may be of significance in the etiology of essential hypertension (EH). Progesterone, dehydroepiandrosterone sulphate (DHEA-S), 11-deoxycortisol and 18-hydroxy-11-deoxycorticosterone (18-OH-DOC), four steroids known to be increased in essential hypertension, were found to have digoxin-like immunoreactivity at levels 1,000 times higher than physiological concentrations. Of these steroids, progesterone and 18-OH-DOC were the most efficient in displacing 3H-ouabain from canine kidney Na+/K+ ATPase whereas progesterone and 11-deoxycortisol were the most potent inhibitors of this enzyme's activity. Although 18-OH-DOC and DHEA-S cross-reacted with digoxin-specific antibodies, their ability to inhibit Na+/K+ ATPase activity was minimal. Although it is concluded that these steroids may contribute to DLIS as isolated from hypertensive patients, it is unlikely that they would be of physiological significance in the etiology of EH unless they were to accumulate and act synergistically within vascular wall smooth muscle tissues.

A study into the nature and organ source of digoxin-like immunoreactive substance(s) in the perinatal period.

Digoxin-like immunoreactive substance(s) (DLIS) was isolated from sera and autopsy-derived tissue obtained from premature and full-term neonates. The highest tissue level of DLIS was in the small bowel followed by the adrenal, gallbladder and liver. Of the fluids examined, meconium had the highest level of DLIS. Preparative high performance liquid chromatography fractionation of cord blood generated at least six different fractions which not only contained DLIS material but also inhibited canine kidney Na+/K+-ATPase activity. Recovery/inhibition studies indicated that 72% of the canine kidney Na+/K+-ATPase inhibition within one fraction could be accounted for on the basis of progesterone content of the fraction.

Duplex ultrasound monitoring of arterial grafts: prospective evaluation in conjunction with ankle pressure indices after femorodistal bypass.

Duplex scanning and ankle brachial pressure indices have been used to objectively assess 94 femoro-distal bypass grafts 4-8 weeks postoperatively. Twenty grafts were occluded. Of the 74 patent grafts, three distinct groups could be identified on the basis of the non-invasive examination. Group 1. Patent grafts with no evidence of haemodynamically significant disease. Group 2. Patent grafts with localised disease. Group 3. Patent: haemodynamically failed grafts. Ankle brachial pressure indices alone could not differentiate between occluded grafts and grafts that were patent: haemodynamically failed (group 3), or adequately separate between grafts in groups 1 and 2. Duplex scanning when combined with pressure indices identified patent grafts "at risk" due to the presence of haemodynamically significant disease. Life table analysis demonstrated appreciable differences in event free survival between group 1 grafts and "at risk" grafts (groups 2 and 3). Duplex scanning is ideal for regular postoperative surveillance and complements the use of ankle brachial pressure indices in the follow-up of femoro-distal grafts.