Diagnostic accuracy of 64-slice computed tomography coronary angiography in a large population of patients without revascularisation: registry data on the comparison between male and female population.

PURPOSE: This study was undertaken to evaluate the diagnostic accuracy of computed tomography coronary angiography (CTCA) for detecting significant coronary artery stenosis (≥50% lumen reduction) compared with conventional coronary angiography (CAG) in a male and female population. MATERIAL AND METHODS: A total of 1,372 patients (882 men, 490 women; mean age 59.3 ± 11.9 years) in sinus rhythm imaged with CTCA (64-slice technology) and CAG were enrolled. Diagnostic accuracy and likelihood ratios (LR+ and LR-) of CTCA were assessed against CAG for the male and female populations. RESULTS: The prevalence of obstructive disease was 53% (men 58%; women 43%). CAG demonstrated the absence of significant coronary artery disease (CAD) in 47% (men 42%; women 56%), single-vessel disease in 25% (men 36%; women 22%) and multivessel disease in 29% (men 32%; women 23%) of patients. In the per-patient analysis, sensitivity, specificity and positive (PPV) and negative (NPV) predictive values of CTCA were 99% (men 98%; women 100%), 92% (men 92%; women 92%), 94% (men 95%; women 90%) and 99% (men 98%; women 100%), respectively. The per-patient likelihood ratios (LR) in the total population (LR+=12.4 and LR-=0.011), the male (LR+=12.9 and LR-=0.016) and female (LR =11.9 and LR-=0) populations were very good. We observed no significant differences in diagnostic accuracy between male and female populations. CONCLUSIONS: CTCA is a reliable diagnostic modality with high sensitivity and NPV in the female population.

Diagnostic accuracy of 64-slice computed tomography coronary angiography in a large population of patients without revascularisation: registry data in NSTEMI acute coronary syndrome and influence of gender and risk factors.

PURPOSE: This study sought to evaluate the diagnostic accuracy of computed tomography coronary angiography (CTCA) for detecting significant coronary artery stenosis (≥50% lumen reduction) compared with conventional coronary angiography (CAG) in non-ST-elevation myocardial infarction-acute coronary syndrome (NSTEMI-ACS) and in subgroups selected by gender and number of risk factors (RF). MATERIALS AND METHODS: We selected from a population of 1,500 patients in a multicentre registry with NSTEMI-ACS who had undergone CTCA and CAG, (n=237; 187 men, mean age 63±10 years). Diagnostic accuracy and likelihood ratios (LR) of CTCA were assessed against CAG in the total population and subgroups (men, women: 0 RF = absence of RF, 1-2 RF = presence of one or two RF, >2 RF = presence of more than two RF). RESULTS: The prevalence of obstructive disease was 53%. In the per-patient analysis, sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of CTCA were 100% (men 100%; women 100%; 0 RF 100%; 1-2 RF 100%; >2 RF 100%), 95% (men 98%; women 50%; 0 RF NA% (NA, not assessable); 1-2 RF 96%; >2 RF 96%), 95% (men 98%; women 91%; 0 RF 91%; 1-2 RF 96%; >2 RF 96%), 100% (men 100%; women 100%; 0 RF NV%; 1-2 RF 100%; >2 RF 100%), respectively. The per-segment analysis showed a reduction in PPV (ranging between 56% and 67%). The per-patient LR+ ranged between 18 and 27, whereas LR-were always 0. We observed no significant differences in diagnostic accuracy between subgroups. CONCLUSIONS: CTCA is a reliable diagnostic modality with high sensitivity and NPV in NSTEMI-ACS patients who are not candidates for early revascularisation, regardless of gender and number of risk factors.

Diagnostic accuracy of 64-slice computed tomography coronary angiography in a large population of patients without revascularisation: registry data on the impact of calcium score.

PURPOSE: This study evaluated the diagnostic accuracy of computed tomography coronary angiography (CTCA) for detecting significant coronary artery stenosis (≥50% lumen reduction) at different coronary calcium score (CACS) values with conventional coronary angiography (CAG) as the reference standard. MATERIAL AND METHODS: A total of 1,500 patients (928 men, mean age 58.2±12.5 years) in sinus rhythm who underwent CTCA (64-slice technology) and CAG were enrolled. Diagnostic accuracy and likelihood ratios (LR) of CTCA were evaluated against CAG for the total population and in different CACS classes (0; 1-10; 11-100; 101-400; 401-1,000; >1,000). RESULTS: The prevalence of obstructive disease was 51% (23.5% single vessel; 27.5% multivessel; progressive increase from 17.9% to 94% through the CACS classes). In the per-patient analysis, sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of CTCA were 99%, 92%, 94% and 99%, respectively. Per-patient analysis showed a worse PPV of CTCA (76-77%) in classes with low CACS (1-10/11-100). Per-patient LR were higher in classes with extreme CACS values (0 = LR+ 18.3 and LR- = 0.0; c1,000 = LR+ 17.0 and LR- = 0.0) with values always >7 for LR+ and <0.033 for LR- for all CACS classes. CONCLUSIONS: CTCA is a reliable diagnostic modality, with high sensitivity and NPV regardless of CACS.

Diagnostic accuracy of 64-slice computed tomography coronary angiography in a large population of patients without revascularisation: registry data and review of multicentre trials.

PURPOSE: This study was undertaken to evaluate the diagnostic accuracy of computed tomography coronary angiography (CT-CA) for the detection of significant coronary artery stenosis (> or =50% lumen reduction) compared with conventional coronary angiography (CCA) in a registry and to review major multicentre trials. MATERIALS AND METHODS: A total of 1,372 patients (882 men, 490 women; mean age 59.3+/-11.9 years) in sinus rhythm were studied with CT-CA (64-slice technology) and CCA. The diagnostic accuracy of CT-CA was evaluated against quantitative CCA as a reference standard for coronary artery stenosis. Positive and negative likelihood ratios and inter- and intraobserver agreement were calculated. RESULTS: The prevalence of disease was 53%. CCA demonstrated the absence of significant coronary artery disease in 46.6% (639/1372), single-vessel disease in 24.7% (337/1372) and multivessel disease in 28.9% (396/1372) of patients. In per-patient analysis sensitivity, specificity and positive and negative predictive value of CT-CA were 99% [confidence interval (CI) 97-99], 92% (CI 89-94), 94% (CI 91-95) and 99% (CI 97-99), respectively. Per-patient and per-segment likelihood ratios (LR+=12.4 and LR-=0.011; LR+=18.3 and LR-=0.064, respectively), were good. Inter- and intraobserver variability was 0.78 and 0.85, respectively. CONCLUSIONS: CT-CA is a reliable diagnostic modality both in terms of sensitivity and negative predictive value. Differences in trial results are also due to the different parameters used for patient inclusion.

Hyperinsulinemia in a normal population as a predictor of non-insulin-dependent diabetes mellitus, hypertension, and coronary heart disease: the Barilla factory revisited.

The study was initiated to evaluate the ability of hyperinsulinemia (as a surrogate measure of insulin resistance) to predict the development in a previously healthy population of three putative outcomes of this abnormality--glucose intolerance, hypertension, and coronary heart disease (CHD). The study involved defining the incidence at which these changes occurred between 1981 and 1993 to 1996 in 647 individuals who were free of any disease when initially studied. The study population consisted of approximately 90% of the subjects evaluated in 1981, divided into quartiles on the basis of the plasma insulin response to a glucose challenge as determined in 1981. The results indicated that the 25% of the population with the highest insulin response in 1981 had significant (P < .001) increases in the incidence of impaired glucose tolerance (IGT) or type 2 diabetes (eightfold), hypertension (twofold), or CHD (threefold). Furthermore, the ability of hyperinsulinemia to predict the three clinical endpoints was independent of differences in age, gender, or body mass index (BMI). Finally, if CHD is considered the clinical endpoint, multiple logistic regression analysis indicates that the values for plasma triglyceride (TG) and mean arterial blood pressure ([MAP] as measured in 1981) also predict the development of CHD. These results indicate that the untoward clinical effects of insulin resistance and/or compensatory hyperinsulinemia, glucose intolerance, hypertension, and CHD clearly can develop in less than 15 years.

Can weight gain in healthy, nonobese volunteers be predicted by differences in baseline plasma insulin concentration?

In this study, we have evaluated the effect, over approximately 14 yr, of differences in baseline degree of hyperinsulinemia on weight gain in 647 healthy, nonobese factory workers. The subjects were divided into 4 quartiles, on the basis of their plasma insulin response to an oral glucose challenge, in 1981. At that time, the mean (+/-SD) plasma insulin concentration, 2 h after the glucose challenge, varied from 18+/-5 to 106+/-42 microU/mL. Despite this approximate 6-fold difference in plasma insulin response at baseline, the weight gain over the period of observation was similar in all quartiles, with mean (+/-SD) increments (kg) of 1.8+/-5.1, 1.6+/-5.3, 2.3+/-5.2, and 2.3+/-5.7, going from the lowest quartile to the highest quartile, in terms of insulin concentration. Furthermore, when the population was considered as a whole, there was no correlation between baseline degree of hyperinsulinemia and change in either absolute (r = 0.004) or percent (r = 0.003) weight gain. Finally, there was no difference in the number of individuals who gained more than 4.5 kg, as a function of their baseline insulin response. Consequently, we conclude that 6-fold differences in plasma insulin responses to glucose do not predict weight gain in a healthy, nonobese population.

The Aer protein and the serine chemoreceptor Tsr independently sense intracellular energy levels and transduce oxygen, redox, and energy signals for Escherichia coli behavior.

We identified a protein, Aer, as a signal transducer that senses intracellular energy levels rather than the external environment and that transduces signals for aerotaxis (taxis to oxygen) and other energy-dependent behavioral responses in Escherichia coli. Domains in Aer are similar to the signaling domain in chemotaxis receptors and the putative oxygen-sensing domain of some transcriptional activators. A putative FAD-binding site in the N-terminal domain of Aer shares a consensus sequence with the NifL, Bat, and Wc-1 signal-transducing proteins that regulate gene expression in response to redox changes, oxygen, and blue light, respectively. A double mutant deficient in aer and tsr, which codes for the serine chemoreceptor, was negative for aerotaxis, redox taxis, and glycerol taxis, each of which requires the proton motive force and/or electron transport system for signaling. We propose that Aer and Tsr sense the proton motive force or cellular redox state and thereby integrate diverse signals that guide E. coli to environments where maximal energy is available for growth.

Quantitative analysis of apoptosis and bcl-2 in Sjögren's syndrome.

OBJECTIVE: To determine whether apoptosis plays a significant role in tissue damage of Sjögren's syndrome (SS). METHODS: We performed a quantitative analysis of programmed cell death on salivary glands of 11 patients. Ten age matched women with sicca syndrome served as controls. Morphometric measurement of the fractional volume of acini and ducts showing DNA strand breaks was performed in sections stained by deoxynucleotidyl transferase assay. The extent of bcl-2 expression was determined in sections labeled with monoclonal antibody. The different cell populations infiltrating the glands were examined in tissues stained with anti-leukocyte common antigen and OPD4 monoclonal antibodies. RESULTS: In patients with SS, 68% of the ductal epithelium was occupied by apoptotic structures, whereas only 12% of acini showed DNA strand breaks. Corresponding values in control salivary glands were 3 and 0.13%. bcl-2 labeling was higher in ducts than in acini of both control and pathologic glands. However, in SS a 43% (p < 0.001) and 75% (p < 0.001) reduction in bcl-2 expression was observed in ductal and acinar epithelium, respectively. In comparison with controls, the numerical density of CD4+ cells and plasma cells scattered throughout the interstitium was 323% and 203% higher (p < 0.001) in SS. Moreover, T helper/inducer lymphocytes represented 52% of the inflammatory foci. CONCLUSION: Apoptosis occurs in minor salivary glands of patients with SS with a prevailing localization on the ductal epithelium in association with downregulation of bcl-2 and a large number of infiltrating CD4+ lymphocytes. Thus, the destruction of glandular tissue and the loss of secretory function in SS is dependent on the activation of the suicide program of epithelial cells.

Dissociation between urinary albumin excretion and variables associated with insulin resistance in a healthy population.

OBJECTIVES: To see if the cluster of metabolic and haemodynamic variables defined as comprising Syndrome X varied as a function of urinary albumin excretion (UAE) rate in a healthy population. DESIGN: A cross-sectional, population-based study. SETTING: A factory in Italy. SUBJECTS: Two hundred and twenty-five healthy volunteers, 115 men and 110 women. OUTCOME MEASURES. Measurements were made of the plasma glucose and insulin responses to oral glucose, fasting triglyceride (TG) and high density lipoprotein (HDL)-cholesterol concentrations, blood pressure, and UAE rates. RESULTS: Only five of the 225 volunteers had micro-albuminuria, defined as a UAE rate > 2 micrograms min-1, and the UAE rate was < 5 micrograms min-1 in 80% of the volunteers. Significant variations in the metabolic and haemodynamic variables measured were not associated with any differences in UAE. Finally, significant relationships were found between various measures of plasma insulin concentration and plasma glucose response to oral glucose, plasma TG and HDL-cholesterol concentrations, and mean arterial blood pressure, independent of variations in age, body mass index, ratio of waist-to-hip girth, and UAE rates. CONCLUSION: The widespread variability in plasma glucose and insulin responses, plasma TG and HDL-cholesterol concentrations, and blood pressure that are seen in the population at large cannot be attributed to variations in UAE rate.

Relevance of residue 116 of HLA-B27 in determining susceptibility to ankylosing spondylitis.

Ankylosing spondylitis (AS) is an autoimmune disorder strongly associated with HLA-B27. A direct role of B27 molecules in the disease pathogenesis has been postulated, possibly by presenting to T cells an as-yet unidentified arthritogenic peptide that triggers the autoimmune response. There are nine HLA-B27 alleles differing from each other at one or more amino acid positions. It is important, for the identification of the arthritogenic peptide, to define which alleles, and therefore which polymorphic positions, predispose to the disease. Here, we report that HLA-B*2709 is not associated with AS, as it was not found in patients. HLA-B*2709 differs from the most frequent and disease-associated HLA-B*2705 allele for a single substitution (His vs. Asp) at position 116. Amino acid 116 is located at the bottom of the groove where the antigenic peptide sits, and it has been proven to influence the peptide-binding specificity of HLA class I molecules. The most likely interpretation of these data is that the differences in charge and size that accompany the His-to-Asp substitution exclude the acceptance of the arthritogenic peptide.

A general method for detecting and sizing large plasmids.

We have devised a method for detecting and estimating the sizes of large bacterial plasmids in the presence of genomic DNA by pulsed-field gel electrophoresis (PFGE). Bacteria harboring plasmids were embedded in agarose and lysed using a rapid protocol. Plugs were incubated with S1 nuclease and subjected to PFGE in agarose gels. S1 nuclease converted supercoiled plasmids into full-length linear molecules. Large plasmids migrated as discrete bands that were readily observed after ethidium staining. Their sizes were reliably estimated by comparison with linear DNA markers. Without S1 digestion, supercoiled plasmids migrated at rates that were not a simple function of their molecular weights, making size determinations problematic. S1-PFGE detected megaplasmids up to 609 kilobases (kb) in six genera of bacteria (Agrobacterium, Escherichia, Klebsiella, Pseudomonas, Salmonella, and Staphylococcus). The procedure gave size values consistent with previous estimates for characterized megaplasmids. Eight new plasmids between 102 and 316 kb were discovered in Klebsiella and Staphylococcus. S1-PFGE avoids the difficulties of plasmid isolation, eliminates the preparation of probes, and does not require knowledge of restriction enzyme cleavage sites. It detects multiple large plasmids up to the limits of PFGE and can be used to screen for megaplasmids in many strains simultaneously.

Microbiologic evaluation of a hydrogen peroxide sterilization system.

The reliability of chemical sterilizers (acetone and/or 30-percent hydrogen peroxide at 25 degrees C and at 60 degrees C) was tested against Bacillus subtilis inoculated onto glass slides, commercial biological indicator discs (Bacillus stearothermophilus and B. subtilis), and B. subtilis spore survival. Acetone alone was not sporicidal. Hydrogen-peroxide-sterilized glass slides were sterile after 5 minutes. The indicator discs required 25 minutes at 25 degrees C, and less than 3 minutes at 60 degrees C (P < .0001). The D value of B. subtilis in 27-percent hydrogen peroxide at 25 degrees C is 2 minutes, with z values of 22 degrees C and 26 degrees C at 25 degrees C and 40 degrees C, respectively. For delicate instruments, a 30-percent peroxide solution followed by an acetone rinse provides an effective alternative to classic heat sterilization.

Salmonella phage PSP3, another member of the P2-like phage group.

Freshly isolated DNA of phage PSP3, whose morphology closely resembles that of phage P2, contained both circular and linear molecules about 31 kb in length. Linear PSP3 DNA molecules possess single-stranded cohesive termini (cos). Sequencing of the fragment anticipated to contain cos revealed a 19-base sequence identical to cos of phage 186. Of the 107 bp to the right of cos, 94 were identical in 186 DNA (88% similarity), and of the 370 bp to the left, 229 were identical (62% similarity). Cos flanking sequences in both P2 and P4 were also highly conserved in PSP3. A number of restriction sites were at similar locations on the two phage DNAs. The parasitic phage P4 propagated on PSP3 lysogens. PSP3 integrates into the Escherichia coli chromosome at 27 min.

Diversity and stability of restriction enzyme profiles of plasmid DNA from methicillin-resistant Staphylococcus aureus.

Nosocomial infections caused by methicillin-resistant Staphylococcus aureus (MRSA) are a significant epidemiological problem. Detecting the sources of epidemic strains and preventing their access to patients, however, depend upon the availability of techniques to reliably distinguish among MRSA strains. We evaluated restriction enzyme analysis of plasmid DNA for use as an epidemiological marker of MRSA strains. The diversity of plasmid types was assessed by examining 120 clinical and environmental MRSA isolates from five southern California hospitals and from the American Type Culture Collection. Thirty-seven distinctive EcoRI digestion patterns were observed. We characterized each strain by the number of plasmids it contained and the sizes of the fragments that were generated by EcoRI. Very few of the isolates (4.2%) lacked plasmids, and some (6.7%) contained DNA that was not digested by EcoRI. Several isolates (12.5%) contained two or more plasmids. We were able to assess the stability of MRSA plasmid types by tracking epidemic strains over a 2-year period. We also examined successive isolates from 10 individual patients during their hospitalization. In all but one case, the patient's plasmid profiles remained unchanged. We conclude that the diversity and stability of MRSA plasmid types make them excellent epidemiological markers. In support of this conclusion, we found that our data provided significant epidemiological insights. Two epidemic strains, accounting for more than half of the infections, were identified in the five hospitals. The remaining cases were sporadic, caused by MRSA strains that appeared very infrequently and that may have originated from sources outside the hospitals.

Elliptic fourier analysis of cell and nuclear shapes.

The elliptic Fourier analysis (EFA) is proposed to characterize the cell and nuclear shape. The principal feature of this method is that it decomposes shapes with a closed contour into subshapes each of which maintains a closed contour. A set of homogeneous, nonredundant descriptors, independent of the contour rotation and translation, is computed from the elliptic Fourier coefficients. These descriptors also account for the contour size and resolution. The paired analysis of the cell and nuclear shape provides an exhaustive and accurate definition of the nucleoplasmic configuration.

Rapid isolation of high-molecular-weight DNA from agarose gels.

We have developed a simple, reliable, and rapid method for recovering DNA from agarose gels. While many methods for DNA extraction have already been described, few provide quantitative recovery of large DNA molecules. These procedures generally require costly apparatus, extended elution times, or considerable handling of the sample after elution. Our method employs a novel electroelution chamber constructed from acrylic plastic. Gel slices containing DNA are placed in the chamber between platinum electrodes. Voltage is applied and a continuous flow of buffer sweeps the eluted DNA from the chamber into an external receptacle. Elution is complete in 7 min. Concentrated DNA is obtained by butanol extraction and alcohol precipitation in 1 h. Recoveries, quantitated by counting radiolabeled DNA or by densitometry of analytical gels, were 94 to 100% for fragments of 4 to 50 kb. The eluted DNA was undegraded and could be digested with restriction enzymes, ligated, end-labeled, or used to transform cells as efficiently as noneluted DNA. Complete elution of a 100-kb plasmid, a 194-kb concatemer of bacteriophage lambda, and of 440- and 550- chromosomes of Saccharomyces cerevisiae was also achieved using the same process. This method is suitable for routine use in a wide range of cloning applications, including the electrophoretic isolation of large DNA molecules.