Noninvasive tests of vascular function and structure: Why and how to perform them

Background Early atherosclerosis involves the endothelium of many arteries. Information about peripheral arterial anatomy and function derived from vascular imaging studies such as brachial artery reactivity (BAR) and carotid intima media thickness (IMT) may be pertinent to the coronary circulation. The prevention and early treatment of atherosclerosis is gaining more attention, and these tests might be used as indications or perhaps guides to the effectiveness of therapy, but their application in clinical practice has been limited. This review seeks to define the anatomy and pathophysiology underlying these investigations, their methodology, the significance of their Findings, and the issues that must be resolved before their application. Methods The literature on BAR and IMT is extensively reviewed, especially in relation to clinical use. Results Abnormal flow-mediated dilation is present in atherosclerotic vessels, is associated with cardiovascular risk factors, and may be a marker of preclinical disease. Treatment of known atherosclerotic risk Factors has been shown to improve flow-mediated dilation, and some data suggest that vascular responsiveness is related to outcome. Carotid IMT is associated with cardiovascular risk factors, and increased levels can predict myocardial infarction and stroke. Aggressive risk factor management can decrease IMT. Conclusions BAR and IMT ate functional and structural markers of the atherosclerotic process. The clinical use of BAR has been limited by varying reproducibility and the influence by exogenous factors, but IMT exhibits less variability. A desirable next step in the development of BAR and IMT as useful clinical tools would be to show an association of improvement in response to treatment with improvement in prognosis.

The effect of high-pass filtering on TEOAE in 2-month-old infants

The aim of the present study was to investigate the effect of high-pass filtering on TEOAE obtained from 2-month-old infants as a function of filter cut-off frequency, activity states and pass/fail status of infants. Two experiments were performed. In Experiment 1, 100 2-month-old infants (200 ears) in five activity states (asleep, awake but peaceful, sucking a pacifier, feeding, restless) were tested by use of TEOAE technology. Five different filter conditions were applied to the TEOAE responses post hoc. The filter conditions were set at 781 Hz (default setting), 1.0, 1.2, 1.4 and 1.6 kHz. Results from this experiment showed that TEOAE parameters, such as whole-wave reproducibility (WR) and signal-to-noise ratio (SNR) at 0.8 kHz and 1.6 kHz, changed as a function of the cut-off frequency. The findings suggest that the 1.6 kHz and 1.2 kHz filter conditions are optimal for WR and SNR pass/fail criteria, respectively. Although all infant recordings appeared to benefit from the filtering, infants in the noisy states seemed to benefit the most. In Experiment 2, the high-pass filtering technique was applied to 23 infants (35 ears) who apparently failed the TEOAE tests on initial screening but were subsequently awarded a pass status based on the results from a follow-up auditory brainstem response (ABR) assessment. The findings showed a significant decrease in noise contamination of the TEOAE with a corresponding significant increase in WR. With high-pass filtering at 1.6 kHz, 21/35 ears could be reclassified into the pass category.

Primary aldosteronism: Are we diagnosing and operating on too few patients?

Many cases of potentially curable primary aldosteronism are currently likely to be diagnosed as essential hypertension unless screening tests based on suppression of renin are tarried out in all hypertensive patients. More than half of the patients with primary aldosteronism detected in this way have normal circulating potassium levels, so measurement of potassium is not enough to exclude primary aldosteronism. When primary aldosteronism is diagnosed, fewer than one-third of patients are suitable for surgery as initial treatment, but this still represents a significant percentage of hypertensive patients. After excluding glucocorticoid-suppressible primary aldosteronism, adrenal venous sampling is essential to detect unilateral production of aldosterone and diagnose angiotensin-responsive aldosterone-producing adenoma. One cannot rely on the computed tomography scan. If all hypertensive patients are screened for primary aldosteronism and the workup is continued methodically in those with a positive screening test, patients with unilateral overproduction of aldosterone who potentially can be cured surgically are not denied the possibility of cure.

Determination of reference values for glucose tolerance, insulin tolerance, and insulin sensitivity tests in clinically normal cats

Objective-To determine reference values and test variability for glucose tolerance tests (GTT), insulin tolerance tests (ITT), and insulin sensitivity tests (IST) in cats, Animals-32 clinically normal cats. Procedure-GTT, ITT, and IST were performed on consecutive days. Tolerance intervals tie, reference values) were calculated as means +/- 2.397 SD for plasma glucose and insulin concentrations, half-life of glucose (T-1/2glucose), rate constants for glucose disappearance (K-glucose and K-itt), and insulin sensitivity index (S-l). Tests were repeated after 6 weeks in 8 cats to determine test variability. Results-Reference values for T-1/2glucose, K-glucose, and fasting plasma glucose and insulin concentrations during GTT were 45 to 74 minutes, 0.93 to 1.54 %/min, 37 to 104 mg/dl, and 2.8 to 20.6 muU/ml, respectively. Mean values did not differ between the 2 tests. Coefficients of variation for T-1/2glucose, K-glucose, and fasting plasma glucose and insulin concentrations were 20, 20, 11, and 23%, respectively. Reference values for K-itt were 1.14 to 7.3%/min, and for S-l were 0.57 to 10.99 x 10(-4) min/muU/ml. Mean values did not differ between the 2 tests performed 6 weeks apart, Coefficients of variation for K-itt and S-l were 60 and 47%, respectively. Conclusions and Clinical Relevance-GTT, ITT, and IST can be performed in cats, using standard protocols. Knowledge of reference values and test variability will enable researchers to better interpret test results for assessment of glucose tolerance, pancreatic beta -cell function, and insulin sensitivity in cats.

The influence of age on weight-bearing joint reposition sense of the knee

Knee joint-position sensitivity has been shown to decline with increasing age, with much of the research reported in the literature investigating this age effect in non-weight-bearing (NWB) conditions. However, little data is available in the more functional position of weight-bearing conditions. The objective of this study was to identify the influence of age on the accuracy and nature of knee joint-position sense (JPS) in both full weight-bearing (FWB) and partial weight-bearing (PWB) conditions and to determine the effect of lower-extremity dominance on knee JPS. Sixty healthy subjects from three age groups (young: 20-35 years old, middle-aged: 40-55 years, and older: 60-75 years) were assessed. Tests were conducted on both the right and left legs to examine the ability of subjects to correctly reproduce knee angles in an active criterion-active repositioning paradigm. Knee angles were measured in degrees using an electromagnetic tracking device, Polhemus 3Space Fastrak, that detected positions of sensors placed on the test limb. Errors in FWB knee joint repositioning did not increase with age, but significant age-related increases in knee joint-repositioning error were found in PWB. It was found that elderly subjects tended to overshoot the criterion angle more often than subjects from the young and middle-aged groups. Subjects in all three age groups performed better in FWB than in PWB. Differences between the stance-dominant (STD) and skill-dominant (SKD) legs did not reach significance. Results demonstrated that for, normal pain-free individuals, there is no age-related decline in knee JPS in FWB, although an age effect does exist in PWB. This outcome challenges the current view that a generalised decline in knee joint proprioception occurs with age. In addition, lower-limb dominance is not a factor in acuity of knee JPS.

Phylogenetic revision of Agapophytinae subf.n. (Diptera : Therevidae) based on molecular and morphological evidence

Agapophytinae subf.n. is a highly diverse lineage of Australasian Therevidae, comprising eight described and two new genera: Agapophytus Guerin-Meneville, Acupalpa Krober, Acraspisa Krober, Belonalys Krober, Bonjeania Irwin & Lyneborg, Parapsilocephala Krober, Acatopygia Krober, Laxotela Winterton & Irwin, Pipinnipons gen.n. and Patanothrix gen.n. A genus-level cladistic analysis of the subfamily was undertaken using sixty-eight adult morphological characters and c. 1000 base pairs of the elongation factor-1 alpha (EF-1 alpha) protein coding gene. The morphological data partition produced three most parsimonious cladograms, whereas the molecular data partition gave a single most parsimonious cladogram, which did not match any of the cladograms found in the morphological analysis. The level of congruence between the data partitions was determined using the partition homogeneity test (HTF) and Wilcoxon signed ranks rest. Despite being significantly incongruent in at least one of the incongruence tests, the partitions were combined in a simultaneous analysis. The combined data yielded a single cladogram that was better supported than that of the individual partitions analysed separately. The relative contributions of the data partitions to support for individual nodes on the combined cladogram were investigated using Partitioned Bremer Support. The level of support for many nodes on the combined cladogram was non-additive and often greater than the sum of support for the respective nodes on individual partitions. This synergistic interaction between incongruent data partitions indicates a common phylogenetic signal in both partitions. It also suggests that criteria for partition combination based solely on incongruence may be misleading. The phylogenetic relationships of the genera are discussed using the combined data. A key to genera of Agapophytinae is presented, with genera diagnosed and figured. Two new genera are described: Patanothrix with a new species (Pat. skevingtoni) and Pat. wilsoni (Mann) transferred from Parapsilocephala, and Pipinnipons with a new species (Pip. kroeberi). Pipinnipons fascipennis (Krober) is transferred from Squamopygin Krober and Pip. imitans (Mann) is transferred from Agapophytus. Agapophytus bicolor (Krober) is transferred from Parapsilocephala. Agapophytus varipennis Mann is synonymised with Aga, queenslandi Krober and Aga. flavicornis Mann is synonymised with Aga. pallidicornis (Krober).

Resolution of natural groups using iterative assignment tests: an example from two species of Australian native rats (Rattus)

Sympatric individuals of Rattus fuscipes and Rattus leucopus, two Australian native rats from the tropical wet forests of north Queensland, are difficult to distinguish morphologically and are often confused in the field. When we started a study on fine-scale movements of these species, using microsatellite markers, we found that the species as identified in the field did not form coherent genetic groups. In this study, we examined the potential of an iterative process of genetic assignment to separate specimens from distinct (e.g. species, populations) natural groups. Five loci with extensive overlap in allele distributions between species were used for the iterative process. Samples were randomly distributed into two starting groups of equal size and then subjected to the test. At each iteration, misassigned samples switched groups, and the output groups from a given round of assignment formed the input groups for the next round. All samples were assigned correctly on the 10th iteration, in which two genetic groups were clearly separated. Mitochondrial DNA sequences were obtained from samples from each genetic group identified by assignment, together with those of museum voucher specimens, to assess which species corresponded to which genetic group. The iterative procedure was also used to resolve groups within species, adequately separating the genetically identified R. leucopus from our two sampling sites. These results show that the iterative assignment process can correctly differentiate samples into their appropriate natural groups when diagnostic genetic markers are not available, which allowed us to resolve accurately the two R. leucopus and R. fuscipes species. Our approach provides an analytical tool that may be applicable to a broad variety of situations where genetic groups need to be resolved.

Impact numbers: measures of risk factor impact on the whole population from case-control and cohort studies

Objective: To describe new measures of risk from case-control and cohort studies, which are simple to understand and relate to numbers of the population at risk. Design: Theoretical development of new measures of risk. Setting: Review of literature and previously described measures. Main results: The new measures are: (1) the population impact number (PIN), the number of those in the whole population among whom one case is attributable to the exposure or risk factor (this is equivalent to the reciprocal of the population attributable risk),- (2) the case impact number (CIN) the number of people with the disease or outcome for whom one case will be attributable to the exposure or risk factor (this is equivalent to the reciprocal of the population attributable fraction); (3) the exposure impact number (EIN) the number of people with the exposure among whom one excess case is attributable to the exposure (this is equivalent to the reciprocal of the attributable risk); (4) the exposed cases impact number (ECIN) the number of exposed cases among whom one case is attributable to the exposure (this is equivalent to the reciprocal of the aetiological fraction). The impact number reflects the number of people in each population (the whole population, the cases, all those exposed, and the exposed cases) among whom one case is attributable to the particular risk factor. Conclusions: These new measures should help communicate the impact on a population, of estimates of risk derived from cohort or case-control studies.

Polymerase chain reaction tests for the identification of Ross River, Kunjin and Murray Valley encephalitis virus infections in horses

Objective To develop and validate specific, sensitive and rapid diagnostic tests using RT-PCR for the detection of Ross River virus (RRV), Kunjin virus (KV) and Murray Valley encephalitis virus (MVEV) infections in horses. Methods Primer sets based on nucleotide sequence encoding the envelope glycoprotein E2 of RRV and on the nonstructural protein 5 (NS5) of KV and MVEV were designed and used in single round PCRs to test for the respective viruses in infected cell cultures and, in the case of RRV, in samples of horse blood and synovial fluid. Results The primer pairs designed for each of the three viruses amplified a product of expected size from prototype viruses that were grown in cell culture. The identity of each of the products was confirmed by nucleotide sequencing indicating that in the context used the RT-PCRs were specific. RRV was detected in serums from 8 horses for which there were clinical signs consistent with RRV infection such that an acute-phase serum sample was taken and submitted for RRV serology testing. The RRV RT-PCR was analytically sensitive in that it was estimated to detect as little as 50 TCID50 of RRV per mL of serum and was specific in that the primer pairs did not amplify other products from the 8 serum samples. The RRV primers also detected virus in three independent mosquito pools known to contain RRV by virus isolation in cell culture. Samples from horses suspected to be infected with KV and MVEV were not available. Conclusion Despite much anecdotal and serological evidence for infection of horses with RRV actual infection and associated clinical disease are infrequently confirmed. The availability of a specific and analytically sensitive RT-PCR for the detection of RRV provides additional opportunities to confirm the presence of this virus in clinical samples. The RTPCR primers for the diagnosis of KV and MVEV infections were shown to be specific for cell culture grown viruses but the further validation of these tests requires the availability of appropriate clinical samples from infected horses.

Reproducibility of a laboratory-based 40-km cycle time-trial on a stationary wind-trainer in highly trained cyclists

The purpose of the present study was to examine the reproducibility of laboratory-based 40-km cycle time-trial performance on a stationary wind-trainer. Each week, for three consecutive weeks, and on different days, forty-three highly trained male cyclists ((x) over bar +/- SD; age = 25 +/- 6 y; mass = 75 +/- 7 kg; peak oxygen uptake [(V) over dot O-2 peak] = 64.8 +/- 5.2 ml x kg(-1) x min(-1)) performed: 1) a (V) over dot O-2 peak test, and 2) a 40-km time-trial on their own racing bicycle mounted to a stationary wind-trainer (Cateye - Cyclosimulator). Data from all tests were compared using a one-way analysis of variance. Performance on the second and third 40-km time-trials were highly related (r = 0.96; p < 0.001), not significantly different (57:21 +/- 2:57 vs. 57:12 +/- 3:14 min:s), and displayed a low coefficient of variation (CV) = 0.9 +/- 0.7%. Although the first 40-km time-trial (58:43 +/- 3:17min:s) was not significantly different from the second and third tests (p = 0.06), inclusion of the first test in the assessment of reliability increased within-subject CV to 3.0 +/- 2.9%. 40-km time-trial speed (km x h(-1)) was significantly (p < 0.001) related to peak power output (W; r = 0.75), (V) over dot O-2 peak (1 x min(-1); r = 0.53), and the second ventilatory turnpoint (1 x min(-1); r = 0.68) measured during the progressive exercise tests. These data demonstrate that the assessment of 40-km cycle time-trial performance in well-trained endurance cyclists on a stationary wind-trainer is reproducible, provided the athletes perform a familiarization trial.

Effects of herbicides diuron and atrazine on corals of the Great Barrier Reef, Australia

In response to recent reports of contamination of the nearshore marine environment along the Queensland coast by herbicides (including areas inside the Great Barrier Reef Marine Park), an ecotoxicological assessment was conducted of the impact of the herbicides diuron and atrazine on scleractinian corals. Pulse-amplitude modulated (PAM) chlorophyll fluorescence techniques were used to assess the herbicide effects on the symbiotic dinoflagellates within the tissues (in hospite) of 4 species of coral (Acropora formosa, Montipora digitata, Porites cylindrica, Seriatopora hystrix) in static toxicity tests, and in freshly isolated symbiotic dinoflagellates from Stylophora pistillata. Using change in the effective quantum yield (DeltaF/F-m') as an effect criterion, diuron (no observable effect concentration, NOEC = 0.3 mug 1(-1); lowest observable effect concentration, LOEC = 1 mug 1(-1); median effective concentration, EC50 4 to 6 mug 1(-1)) was found to be more toxic than atrazine (NOEC = 1 mug 1(-1), LOEC = 3 mug 1(-1), EC50 40 to 90 mug 1(-1)) in short-term (10 h) toxicity tests. In the tests with isolated algae, significant reductions in DeltaF/F-m' were recorded as low as 0.25 mug 1(-1) diuron (LOEC, EC50 = 5 mug 1(-1)). Time-course experiments indicated that the effects of diuron were rapid and reversible. At 10 mug 1(-1) diuron, DeltaF/F-m' was reduced by 25% in 20 to 30 min, and by 50% in 60 to 90 min. Recovery of DeltaF/F-m' in corals exposed to 10 mug 1(-1) diuron and then transferred to running seawater was slower, returning to within 10% of control values inside 1 to 7 h. The effect of a reduction in salinity (35 to 27%) on diuron toxicity (at 1 and 3 mug 1(-1) diuron) was tested to examine the potential consequences of contaminated coastal flood plumes inundating inshore reefs. DeltaF/F-m' was reduced in the diuron-exposed corals, but there was no significant interaction between diuron and reduced salinity seawater within the 10 h duration of the test. Exposure to higher (100 and 1000 mug 1(-1)) diuron concentrations for 96 h caused a reduction in DeltaF/F-m' the ratio variable to maximal fluorescence (F,1F.), significant loss of symbiotic dinoflagellates and pronounced tissue retraction, causing the corals to pale or bleach. The significance of the results in relation to diuron contamination of the coastal marine environment from terrestrial sources (mainly agricultural) and marine sources (antifouling paints) are discussed.

Effect of the Impact Conditions on the Mechanical Properties of Injection-Molded Parts

This work focused on the study of the impact event on molded parts in the framework of automotive components. The influence of the impact conditions and processing parameters on the mechanical behavior of talc-filled polypropylene specimens was analyzed. The specimens were lateral-gate discs produced by injection molding, and the mechanical characterization was performed through instrumented falling weight impact tests concomitantly assisted with high-speed videography. Results analyzed using the analysis of variance (ANOVA) method have shown that from the considered parameters, only the dart diameter and test temperature have significant influence on the falling weight impact properties. Higher dart diameter leads to higher peak force and peak energy results. Conversely, higher levels of test temperatures lead to lower values of peak force and peak energy. By means of high-speed videography, a more brittle fracture was observed for experiments with higher levels of test velocity and dart diameter and lower levels of test temperature. The injection-molding process conditions assessed in this study have an influence on the impact response of moldings, mainly on the deformation capabilities of the moldings.

The need for standardized tests to evaluate the reliability of data transport in wireless medical systems

Wireless medical systems are comprised of four stages, namely the medical device, the data transport, the data collection and the data evaluation stages. Whereas the performance of the first stage is highly regulated, the others are not. This paper concentrates on the data transport stage and argues that it is necessary to establish standardized tests to be used by medical device manufacturers to provide comparable results concerning the communication performance of the wireless networks used to transport medical data. Besides, it suggests test parameters and procedures to be used to produce comparable communication performance results.

Feeding non-preference by Spodoptera frugiperda and Spodoptera eridania on tomato genotypes

Larvae of the genus Spodoptera spp. are highly polyphagous and can cause economical losses in several agricultural crops. Given their growing importance in the tomato crop, especially for industry, this work aimed to evaluate the feeding non-preference by larvae of Spodoptera frugiperda (J. E. Smith, 1797) and Spodoptera eridania (Cramer, 1782) on tomato genotypes and classify them by the levels of resistance. The commercial cultivar Santa Clara was set as the susceptible standard and line PI 134417 as the resistant standard to evaluate the lines PI 134418, PI 126931, LA 462 and LA 716. Feeding non-preference tests were performed under non-choice and free-choice conditions to evaluate the genotype attractiveness to larvae at predetermined times after their release, as well as the leaf area consumed. Overall, the genotypes LA 716 and PI 126931 were the least attractive to S. frugiperda, whereas Santa Clara was the most attractive and consumed. For S. eridania, the genotypes PI 126931, LA 462, LA 716 and PI 134418 were the least preferred for feeding, and Santa Clara and PI 134417 were the most attractive and consumed. The genotypes LA 716 and PI 126931 are moderately resistant to S. frugiperda and S. eridania; PI 134418 and LA 462 are moderately resistant to S. eridania; PI 134417 is susceptible to S. frugiperda and S. eridania; and Santa Clara is highly susceptible to both S. frugiperda and S. eridania.

Agronomic performance of 27 cocoa progenies and plant selection based on productivity, self-compatibility and disease resistance

The objective of the present work was to evaluate 27 progenies of cocoa crosses considering the agronomic traits and select F1 plants within superior crosses. The experiment was installed in March 2005, in the Experimental Station Joaquim Bahiana (ESJOB), in Itajuipe, Bahia. The area of the experiment is of approximately 3 ha, with a total of 3240 plants. Thirteen evaluations of vegetative brooms, five of cushion brooms and 15 of number of pods per plant were accomplished. Thirty pollinations were made for each selected plant to test for self-compatibility. The production, based on the number of pods per plant, and resistance to witches´ broom indicated CEPEC 94 x CCN 10, RB 39 x CCN 51 and CCN 10 x VB 1151 as superior progenies. All selections tested were self-compatible. The analyses of progenies and individual tree data, associated to visual field observations, allowed the selection of 17 plants which were included in a network of regional tests to determine the phenotypic stability.