Paradoxical behavior of the QT interval during exercise and recovery and its relationship with cardiac memory

BACKGROUND

Few studies have dealt with the behavior of the corrected (QTc) and uncorrected QT intervals during exercise and recovery.

HYPOTHESIS

Based on previously published dynamics of the QT interval during treadmill testing, this study attempted to reevaluate the computer-proposed underlying mechanisms of these dynamics and to determine whether the so-called memory phenomenon could be operative in some subjects without evidence of structural heart disease.

METHODS

This study included 42 unmedicated healthcare volunteers, 23 men and 19 women aged between 20 and 42 (mean 31.7) years. All had normal physical examinations, x-rays, and transthoracic echocardiograms. The electrocardiograms were also normal with 12-lead QT interval dispersions of < 90 ms.

RESULTS

During exercise and recovery, the behavior of the QT intervals permitted the categorization into two groups. In Group 1 (31/42; 73.8% of subjects) the uncorrected QT interval showed a biphasic pattern consisting of a gradual decrease during incremental exercise followed by a gradual increase during recovery. In contrast, the QTc interval had a triphasic pattern resulting from a slight increase during the early phase of exercise, a gradual decrease at the highest rates, and a final increase during recovery as the rate slowed to control values. In Group 2 (11/42; 36.2% of subjects) the behavior was considered as paradoxical since the uncorrected QT interval displayed in a triphasic pattern whereas the QTc interval yielded a tetraphasic pattern due to the fact that both showed a second decrease during recovery while the rate was decreasing.

CONCLUSIONS

Analysis of dynamics behavior of the QTc and the uncorrected QT intervals during exercise showed that some normal subjects had a paradoxical behavior which, because of its temporal relation to the phases of exercise, could be an expression of the so-called memory phenomenon.

Upper limits on a stochastic background of gravitational waves

The Laser Interferometer Gravitational-Wave Observatory has performed a third science run with much improved sensitivities of all three interferometers. We present an analysis of approximately 200 hours of data acquired during this run, used to search for a stochastic background of gravitational radiation. We place upper bounds on the energy density stored as gravitational radiation for three different spectral power laws. For the flat spectrum, our limit of omega0 < 8.4 x 10(-4) in the 69-156 Hz band is approximately 10(5) times lower than the previous result in this frequency range.

Chromogranin A levels and mortality in patients with severe sepsis

CONTEXT

Chromogranin A (CgA) is a novel biomarker with potential to assess mortality risk of patients with severe sepsis.

OBJECTIVE

Assess association of CgA levels and mortality risk of severely septic patients.

METHODS

Serum CgA levels were measured in 50 hospitalized, severely septic patients with organ failure <48 h.

RESULTS

Higher CgA levels trended toward higher ICU and hospital mortality. Patients without cardiovascular disease who died in the ICU had higher median (IQR) CgA levels 602.3 (343.3, 1134.3) ng/ml versus 205.5 (130.7, 325.9) ng/ml, p = 0.01.

CONCLUSIONS

High CgA levels predict ICU mortality in severely septic patients without prior cardiovascular disease.

Isotropic finishing of austempered iron casting cylindrical parts by roller burnishing

Roller burnishing technique to achieve isotropic surface topography on cylindrical components made of austempered ductile iron (ADI) casting is presented in this paper. In the last years, ADI casting components are used in many mechanical applications, due to their enhanced mechanical properties. ADI castings are difficult-to-cut materials; therefore, advanced techniques to improve manufacturing productivity are necessary and under research. On the other hand, spiral roughness pattern produced by turning operation is a common source of unconformities in several applications. Turning produces a defined kinematic pattern, similar to a thread. This work presents a theoretical and experimental validation using different burnishing conditions. Roughness and surface topography and surface integrity were checked. Results show that the technique greatly improves surface roughness, and eliminates the kinematic-driven roughness pattern of turning, leading to a more isotropic finishing. A comparison between roller burnishing and ball burnishing is also presented in this paper.

Third trimester uterine artery Doppler indices as predictors of preeclampsia and neonatal small for gestational age

Objective: To test the hypothesis that third-trimester uterine artery Doppler (UAD) predicts adverse pregnancy and neonatal outcomes in a high-risk population.Study design: This is a nested case control study of women with singleton gestations referred for a fetal growth ultrasound between 24 and 36 weeks. Third-trimester UAD was performed if estimated fetal weight (Hadlock's chart) was <20th percentile as these patients were considered high risk for poor pregnancy outcomes. The primary outcomes assessed were neonatal small for gestational age (SGA) and hypertensive disorders. Secondary outcomes included pH <7.10, NICU admission, Apgar <7 at 5 minutes, respiratory distress syndrome, hypoglycemia, and a composite (presence of one or more of the secondary outcomes) neonatal adverse outcome. The sensitivity and specificity of the UAD indices for predicting these outcomes were compared.Results: Among 200 women included, neonatal SGA occurred in 91 (46%) neonates, preeclampsia in 21 (10.5%), early preeclampsia in 4 (2%) and a composite adverse outcome in 67 (34%) neonates. Abnormal UAD indices, specifically left uterine artery notching and pulsatile index (PI) >95th percentile, were significantly correlated with an increased relative risk (RR) of a number of outcomes. Left uterine artery notching was significantly associated with SGA, RR 1.76 (1.03-3.04), preeclampsia, RR 2.53 (1.47-4.37) and early preeclampsia, RR 2.88 (1.34-6.20). The PI >95th percentile was significantly associated with SGA, RR 1.83 (1.21-2.76), NICU admission, RR 1.79 (1.14-2.79), preeclampsia, RR 1.98 (1.29-3.03), and early preeclampsia, RR 3.13 (2.54-3.86). The mean UAD PI >95th percentile had the best sensitivity for SGA, but the area under the ROC curve (AUC) was modest (0.60, 95% CI = 0.53-0.67). Left uterine artery notching and PI >95th percentile had similar predictive utility for preeclampsia AUC 0.65, 95% CI = 0.53-0.76 (mean uterine artery PI >95th percentile) and AUC 0.66, 95% CI = 0.54-0.77 (left uterine artery notching).Conclusion: Abnormal third-trimester UAD indices are associated with adverse perinatal outcomes including neonatal SGA, preeclampsia, and early preeclampsia. Though statistically significantly correlated, the predictive value of UAD indices for adverse pregnancy and neonatal outcomes was modest.

Search for coherent charged pion production in neutrino-carbon interactions

We report the result from a search for charged-current coherent pion production induced by muon neutrinos with a mean energy of 1.3 GeV. The data are collected with a fully active scintillator detector in the K2K long-baseline neutrino oscillation experiment. No evidence for coherent pion production is observed, and an upper limit of is set on the cross section ratio of coherent pion production to the total charged-current interaction at 90% confidence level. This is the first experimental limit for coherent charged pion production in the energy region of a few GeV.

Amrinone stimulation test: ability to predict improvement in left ventricular ejection fraction after coronary bypass surgery in patients with poor baseline left ventricular function

OBJECTIVES

This study sought to determine whether the response to amrinone in patients with severe baseline left ventricular dysfunction can predict improvement in left ventricular ejection fraction after coronary artery bypass graft surgery.

BACKGROUND

Previous studies have suggested that the inotropic response to dobutamine can identify viable myocardium in the setting of chronic coronary disease and left ventricular dysfunction. However, increased oxygen demand stimulated by dobutamine can lead to superimposition of ischemia on the hibernating state, potentially confounding interpretation of results. Amrinone is an inotropic agent that does not critically augment myocardial oxygen demand and may be useful for identification of hibernating myocardium in the chronically ischemic state.

METHODS

Forty-four consecutive patients with coronary artery disease and left ventricular ejection fraction < 40% referred for coronary artery bypass graft surgery underwent amrinone stimulation (1 mg/kg body weight). Left ventricular ejection fraction was determined before amrinone stimulation, 20 min after infusion and 21 days after bypass surgery.

RESULTS

Baseline ejection fraction was 28 +/- 7% (mean +/- SD). Ejection fraction increased to 35 +/- 5% after amrinone stimulation (p < 0.0001) and to 33 +/- 6% after bypass surgery (p < 0.0001). Postbypass ejection fraction was significantly correlated with postamrinone ejection fraction (r = 0.65, p < 0.0001). Furthermore, the change in ejection fraction from baseline to after bypass surgery was highly correlated with the change in ejection fraction after amrinone stimulation (r = 0.75, p < 0.0001). Of 13 patients with an increase in ejection fraction > or = 10% after amrinone, all 13 had an increase of at least 8% and 11 (85%) of 13 had an increase > or = 10% after bypass surgery. In contrast, of 31 patients with an increase in ejection fraction < 10% after amrinone, only 2 (6%) had an increase > or = 10% (p < 0.0001) and 28 (90%) of 31 had an increase < 5% after bypass surgery.

CONCLUSIONS

Augmentation of myocardial contraction by amrinone in patients with chronic coronary artery disease and severe baseline left ventricular dysfunction predicts improvement in left ventricular ejection fraction after coronary artery bypass graft surgery.

Results (>6 months) of stenting of >1 major coronary artery in multivessel coronary artery disease

Multivessel percutaneous transluminal coronary angioplasty (PTCA) is associated with a high requirement for further revascularization procedures. Although stenting can reduce restenosis and clinical events after 1-vessel intervention, little information is available after multivessel coronary stenting. We followed up 136 patients (9% of 1,481 undergoing stenting in our center) who had had stent implantation in at least 2 different major native coronary arteries and were followed-up for >6 months. Each patient had received a mean of 2.3 +/- 0.6 stents (1.13 +/- 0.4 stents per lesion) and procedural success was 95%. In-hospital complications included 1 death, 1 Q-wave infarction, 5 non-Q-wave myocardial infarctions, and 1 repeat PTCA. After a mean of 18 +/- 13 months, 7 patients died (3 of heart failure, 4 of noncardiac causes), 2 required coronary bypass surgery, 1 had a myocardial infarction, 13 target vessel repeat PTCA, and 4 non-target vessel PTCA. Survival free of major cardiac events was 75% at 3 years. A history of heart failure, dilation of a restenotic lesion, and 3-vessel dilation were independent negative predictors of event-free survival. Angiographic follow-up was available in 86 patients: 56 (65%) were restenosis free, 23 (27%) had 1-vessel restenosis, and 6 (7%) had 2-vessel and 1 patient 3-vessel restenosis. Restenosis per vessel was 23% (41 of 177). Reference diameter, past-PTCA minimal luminal diameter, and length of the stent were independent predictors of restenosis. We conclude that multivessel stenting provides good midterm results in selected patients with multivessel coronary artery disease. Midterm events are less frequent than previously reported after balloon PTCA.

Immunocytochemical study of type IV collagen and laminin in canine mammary tumours

We performed an immunohistochemical study of the basement membrane (BM) proteins laminin and type IV collagen in 35 canine mammary tumours, histologically classified according to the World Health Organization's suggested classification. Laminin and type IV collagen were seen in extracellular locations but only laminin was present in epithelial and myoepithelial cells and chondrocytes. The BM was always continuous in adenomas and fibroadenomas. In the 20 malignant tumours studied, the basement membrane was continuous in one, discontinuous in five, and virtually absent in 14. When present, the BM of malignant tumours varied in width and distribution in the same area. The benign and malignant mixed tumours did not have BM separating epithelial and newly-formed mesenchymal structures. In areas of abundant myoepithelial cells in complex and mixed tumours, both benign and malignant, there were groups of BM fragments which differed in length and thickness and occasionally formed tangles. We have called these 'membranous thickets'. Our results indicate that myoepithelial cells are the main source of the BM proteins laminin and type IV collagen in canine mammary tumours.

Modification to the AOAC Sporicidal Activity of Disinfectants Test (Method 966.04): Collaborative Study

In an effort to improve AOAC Method 966.04, the Sporicidal Activity of Disinfectants Test, selected modifications to the procedure were evaluated in a collaborative study. Method 966.04 is used to generate efficacy data to support the product registration of sporicides and sterilants. The method is a carrier-based test that provides a qualitative measure of product efficacy against spores of Bacillus subtilis and Clostridium sporogenes. The use of garden soil extract and the lack of standard procedures for the enumeration of spores and neutralization of the test chemicals have been considered problematic for many years. The proposed modifications were limited to the B. subtilis and hard surface carrier (porcelain penicylinder) components of the method. The study included the evaluation of a replacement for soil extract nutrient broth and an establishment of a minimum spore titer per carrier, both considered crucial for the improvement and utilization of the method. Additionally, an alternative hard surface material and a neutralization confirmation procedure were evaluated. To determine the equivalence of the proposed alternatives to the standard method, 3 medium/carrier combinations, (1) soil extract nutrient broth/porcelain carrier (current method), (2) nutrient agar amended with 5 g/mL manganese sulfate/porcelain carrier, and (3) nutrient agar amended with 5 g/mL manganese sulfate/stainless steel carrier were analyzed for carrier counts, HCl resistance, efficacy, quantitative efficacy, and spore wash-off. The test chemicals used in the study represent 3 chemical classes and are commercially available antimicrobial liquid products: sodium hypochlorite (bleach), glutaraldehyde, and a combination of peracetic acid and hydrogen peroxide. Four laboratories participated in the study. The results of the spore titer per carrier, HCl resistance, efficacy, and wash-off studies demonstrate that amended nutrient agar in conjunction with the porcelain is comparable to the current method, soil extract nutrient broth/porcelain. The nutrient agar method is simple, inexpensive, reproducible, and provides an ample supply of high quality spores. Due to the current use of porcelain carriers for testing C. sporogenes, it is advisable to retain the use of porcelain carriers until stainless steel can be evaluated as a replacement carrier material for Clostridium. The evaluation of stainless steel for Clostridium has been initiated by the Study Director. Study Director recommendations for First Action revisions are provided in a modified method.

Entrapment and obstruction of the esophagus from thoracic spine hyperextension-dislocation injury

We have reported a unique case of esophageal entrapment and obstruction from a thoracic spine hyperextension-dislocation injury after a motor vehicle crash. Because the risk for esophageal injury is not typically associated with thoracic spine injury, a heightened sensitivity for developing symptoms and signs is at least necessary. As with any injury to the gastrointestinal tract, optimal therapy requires resuscitation and prompt operative intervention.

Leishmania (Viannia) guyanensis: a new minicircle class exclusive to this specie isolated from a DNA cosmid library useful for taxonomic purposes

A new minicircle class exclusive to this specie isolated from a DNA cosmid library useful for taxonomic purposes. Experimental Parasitology 94, 143-149. In this paper we describe a new minicircle class exclusive to Leishmania (Viannia) guyanensis. The minicircle class was obtained with the aid of a total DNA cosmid library. The library was screened with an EcoRI fragment isolated from L. (V.) guyanensis (M4147). After screening seven clones were selected which showed strong hybridisation. Clones were digested and hybridised with the same probe. After hybridisation only one clone containing the desired fragment was positive. The fragment sized around 1000 bp was subcloned into pBluescript for sequencing. Sequence analysis using the GCG programme showed no substantial homology with any sequences previously reported, apart from the expected homology with the conserved region of Leishmania kDNA sequences. The probe hybridised strongly only to L. (V.) guyanensis kDNA after medium stringency washing.

Protective immunity induced by daily bites from irradiated mosquitoes infected with Plasmodium yoelii

Individuals in malaria endemic regions do not develop fully protective immune responses against Plasmodium liver stage infections. In high transmission areas, individuals can be exposed to more than two infective mosquito bites daily. Their exposure to Plasmodium sporozoites, therefore, is in the form of small and frequent doses. This is very different from individuals studied in controlled immunization trials where the delivery of large numbers of radiation-attenuated sporozoites in a limited number of doses can induce sterile protective immunity. Using irradiated mosquitoes infected with Plasmodium yoelii 17XNL, we tested whether daily bites from a few mosquitoes can induce a protective immune response in mice. This immunization strategy successfully induced a protective response, preventing the development of liver stages when mice were challenged with nonirradiated sporozoites. These results provide further support for the development of liver stage vaccines. They are also a call for further study into why fully protective responses against the liver stage are not seen in individuals from endemic regions.

Plasma sex steroids and SHBG in patients with breast cancer and their relation to tumor oestrogen-dependency

In order to evaluate the possible role of sex steroids in breast cancer and their relation to the presence of oestradiol receptors (ER), ER were quantified in 112 breast adenocarcinomas and 14 benign tumours. The sex hormones of the patients were determined in plasma: oestradiol (E2), progesterone, testosterone, androstenedione, as well as SHBG and gonadotrophins. The ER were evaluated in cytosolic and nuclear fractions. Steroids and gonadotrophins were determined by RIA. SHBG was determined by following a procedure of saturation with tritiated dihydrostestosterone. The mean levels of E2 in postmenopausal women with breast cancer was found to be significantly higher than of the control group. However, no significant variations for the rest of the steroids were seen among the patients with breast cancer and the control group or benign tumour. Nor was any relation found between the presence of ER and the hormonal steroids studied or SHBG. It is suggested that the possible influence of the sex steroids in the etiopathogenesis of breast cancer might be due to the greater production accompanied by a parallel metabolic clearance that would maintain their plasma levels.

Nonesophageal side-effects after antireflux surgery plus acid-suppression duodenal diversion surgery in patients with long-segment Barrett's esophagus*

During the last years we have employed acid-suppression duodenal diversion procedures (truncal vagotomy-partial gastrectomy plus Roux-en-Y gastrojejunostomy) in addition to antireflux surgery in order to treat all the pathophysiological factors involved in the genesis of Barrett's esophagus. We have observed very good results concerning the clinical and objective control of GERD at the long-term follow up after this procedure. However, it could be associated with other nonesophageal symptoms or side-effects. This study was conducted to evaluate the presence of gastrointestinal symptoms (diarrhea, vomiting, dumping, weight loss and anastomotic ulcers) after this operation. In this prospective study 73 patients were assessed using a careful clinical questionnaire asking regarding these complications at the early (< 6 months) and late (> 6 months) follow-up (average of 32.4 months). In the early postoperative period, diarrhea was present in 64% (19% considered severe 10-90 days after surgery), dumping in 41% and loss of weight in 71% of cases. Diarrhea occurred daily in 47.7% in the early postoperative period, but only in 16% of cases after 1 year. Shortly after surgery, steatorrea was observed in 9% of cases and responded well to medical treatment. Severe diarrhea or dumping was rare (5% of cases). These symptoms improved significantly after 1 year with medical management (45%, 20% and 30%, respectively) and 42% of patients regained their normal body weight. Only two patients presented anastomotic ulcers and were treated satisfactory with proton pump inhibitors. Revisional surgery was indicated in two patients with severe dumping syndrome. Most side-effects identified by this study were mild and diminished 1 year after operation.

Decrease in detectable complement receptor type 1 levels on erythrocytes from patients with psoriatic polyarthritis

The complement receptor type 1 (CR1) levels on erythrocyte membranes from 23 patients with PsA was determined by using ELISA. Six patients had an axial form, the rest had peripheral arthritis (10 polyarthritis and seven oligoarthritis). A significant decrease in levels of this receptor was found in patients with polyarthritis compared with healthy controls. Non-significant differences were found when comparing the other two groups of patients with the controls, although the mean values of CR1 were lower in the patients' group. We also found an inverse correlation between CR1 levels and articular index, but not with ESR, CRP or disease duration. No differences in the CR1 density were obtained for HLA-B27 positive and HLA-B27 negative patients.

Prognostic value of brachioradialis muscle oxygen saturation index and vascular occlusion test in septic shock patients

OBJECTIVES

To compare rSO2 (muscle oxygen saturation index) static and dynamic variables obtained by NIRS (Near Infrared Spectroscopy) in brachioradialis muscle of septic shock patients and its prognostic implications.

DESIGN

Prospective and observational study.

SETTING

Intensive care unit.

SUBJECTS

Septic shock patients and healthy volunteers.

INTERVENTIONS

The probe of a NIRS device (INVOS 5100) was placed on the brachioradialis muscle during a vascular occlusion test (VOT).

VARIABLES

Baseline, minimum and maximum rSO2 values, deoxygenation rate (DeOx), reoxygenation slope (ReOx) and delta value.

RESULTS

Septic shock patients (n=35) had lower baseline rSO2 (63.8±12.2 vs. 69.3±3.3%, p<0.05), slower DeOx (-0.54±0.31 vs. -0.91±0.35%/s, p=0.001), slower ReOx (2.67±2.17 vs. 9.46±3.5%/s, p<0.001) and lower delta (3.25±5.71 vs. 15.1±3.9%, p<0.001) when compared to healthy subjects (n=20). Among septic shock patients, non-survivors showed lower baseline rSO2 (57.0±9.6 vs. 69.8±11.3%, p=0.001), lower minimum rSO2 (36.0±12.8 vs. 51.3±14.8%, p<0.01) and lower maximum rSO2 values (60.6±10.6 vs. 73.3±11.2%, p<0.01). Baseline rSO2 was a good mortality predictor (AUC 0.79; 95%CI: 0.63-0.94, p<0.01). Dynamic parameters obtained with VOT did not improve the results.

CONCLUSION

Septic shock patients present an important alteration of microcirculation that can be evaluated by NIRS with prognostic implications. Monitoring microvascular reactivity in the brachioradialis muscle using VOT with our device does not seem to improve the prognostic value of baseline rSO2.

Alpha linolenic acid in cholesterol esters: a marker of alphalinolenic acid intake in newborns

OBJECTIVE

To evaluate alpha-linolenic acid (ALA) (18&ratio;3 n-3) and linolenic acid (LA) (18&ratio;2 n-6) in cholesterol esters (CE) as markers of ALA and LA dietary intakes in preterm infants.

SUBJECTS

Forty-five preterm infants: two groups fed different formulas, the third fed human milk.

DESIGN

ALA and LA dietary intakes were precisely recorded in each infant to accurately determine the cumulative amount of ingested ALA and LA during two intervals: (i) between the second day after the first significant formula intake (D0) and the fifteenth day (D15); and (ii) between D0 and the first day of the 37th week of post-conception age (W37). The corresponding amounts of ingested ALA and LA were related to ALA and LA levels determined by capillary column gas-liquid chromatography in plasma cholesterol esters at D15 and W37, respectively.

RESULTS

ALA in CE was very significantly correlated to D0-D15 and D0-W37 ALA intakes (0.66; P=0.0001 and 0.70; P=0.0001), respectively. LA in CE was weakly correlated to D0-D15 LA intakes (0.03; P=0.01) and whatever the group (human milk or enriched formula) the correlation was lost at W37.

CONCLUSION

In preterm infants, ALA in CE can be considered as representative of ALA dietary intakes, whereas LA in CE appears as a poor marker of LA intakes.

Hydro-climatic changes of wetlandscapes across the world

Assessments of ecosystem service and function losses of wetlandscapes (i.e., wetlands and their hydrological catchments) suffer from knowledge gaps regarding impacts of ongoing hydro-climatic change. This study investigates hydro-climatic changes during 1976-2015 in 25 wetlandscapes distributed across the world's tropical, arid, temperate and cold climate zones. Results show that the wetlandscapes were subject to precipitation (P) and temperature (T) changes consistent with mean changes over the world's land area. However, arid and cold wetlandscapes experienced higher T increases than their respective climate zone. Also, average P decreased in arid and cold wetlandscapes, contrarily to P of arid and cold climate zones, suggesting that these wetlandscapes are located in regions of elevated climate pressures. For most wetlandscapes with available runoff (R) data, the decreases were larger in R than in P, which was attributed to aggravation of climate change impacts by enhanced evapotranspiration losses, e.g. caused by land-use changes.