The effect of mammographic screening on invasive breast cancer in Western Australia

Objective: To determine whether mammographic screening has affected the presentation of invasive breast cancer in Western Australia. Design: Population-based reviews of the presentation of all invasive breast cancers diagnosed in Western Australia in 1989 and 1994. Setting: Western Australia (population 1.8 million), Active recruitment of women aged 50-69 years for mammographic screening began in 1989. Main outcome measures: Size and stage of invasive breast cancers at diagnosis. Results: From 1989 to 1994, the age-standardised incidence rose from 109 to 123 per 100 000 woman-years, based on 584 and 750 cases, respectively. The proportion of all invasive breast cancers detected as a result of a mammogram increased from 9.2% in 1989 to 34.5% in 1994. Among the cases where relevant information was recorded, the proportion of impalpable tumours increased from 7.7% in 1989 to 27.6% in 1994, and the average size of palpable tumours fell. There was an unexpected increase in the proportion of tumours that were negative on assays for oestrogen and progesterone receptors. Conclusions: A relatively simple and inexpensive clinical review has boosted confidence that the outlay of public monies required to establish and conduct screening in Australia appears likely to yield the reductions in mortality from breast cancer that would be predicted on the basis of the earlier controlled trials of mammography.

Mothers' mental illness and child behavior problems: Cause-effect association or observation bias

Objective: A number, of studies have consistently found that a mother's mental health (particularly her level of depression) is a strong predictor of mental health problems experienced by her child(ren). However, the validity of this finding is in doubt because the majority of these studies have relied on maternal reports as indicators of children's behavior. Method: This prospective, longitudinal study examines data an the mental health of the mother from prior to the birth of her child to when the child reaches 14 years of age. Child behavior is measured at 14 years of age using reports from mother and child. Mother and child responses are compared to provide an indication of the possible magnitude of maternal observation bias in the reporting of child behavior problems. Results: Anxious and/or depressed mothers tend to report more cases of child behavior problems than do their mentally healthy counterparts or children themselves. Differences between mothers and youths In reporting behavior problems appear to be related to the mothers' mental health. Conclusions: Current maternal mental health impairment appears to have a substantial effect on the reporting of child behavior problems by the mother, thereby raising questions about the validity of reports of child behavior by persons who are currently emotionally distressed.

Effect of coinfection with STDs and of STD treatment on HIV shedding in genital-tract secretions - Systematic review and data synthesis

Objective: To determine whether coinfection with sexually transmitted diseases (STD) increases HIV shedding in genital-tract secretions, and whether STD treatment reduces this shedding. Design: Systematic review and data synthesis of cross-sectional and cohort studies meeting. predefined quality criteria. Main Outcome Measures: Proportion of patients with and without a STD who had detectable HIV in genital secretions, HIV toad in genital secretions, or change following STD treatment. Results: Of 48 identified studies, three cross-sectional and three cohort studies were included. HIV was detected significantly more frequently in participants infected with Neisseria gonorrhoeae (125 of 309 participants, 41%) than in those without N gonorrhoeae infection (311 of 988 participants, 32%; P = 0.004). HIV was not significantly more frequently detected in persons infected with Chlamydia trachomatis (28 of 67 participants, 42%) than in those without C trachomatis infection (375 of 1149 participants, 33%; P = 0.13). Median HIV load reported in only one study was greater in men with urethritis (12.4 x 10(4) versus 1.51 x 10(4) copies/ml; P = 0.04). In the only cohort study in which this could be fully assessed, treatment of women with any STD reduced the proportion of those with detectable HIV from 39% to 29% (P = 0.05), whereas this proportion remained stable among controls (15-17%), A second cohort study reported fully on HIV load; among men with urethritis, viral load fell from 12.4 to 4.12 x 10(4) copies/ml 2 weeks posttreatment, whereas viral load remained stable in those without urethritis. Conclusion: Few high-quality studies were found. HIV is detected moderately more frequently in genital secretions of men and women with a STD, and HIV load is substantially increased among men with urethritis, Successful STD treatment reduces both of these parameters, but not to control levels. More high-quality studies are needed to explore this important relationship further.

Synthesis of silica films at the air/water interface: Effect of template chain length and ionic strength

We have grown surfactant-templated silicate films at the air-water interface using n-alkyltrimethylammonium bromide and chloride in an acid synthesis with tetraethyl orthosilicate as the silicate source. The films have been grown with and without added salt (sodium chloride, sodium bromide) and with n-alkyl chain lengths from 12 to 18, the growth process being monitored by X-ray reflectometry. Glassy, hexagonal, and lamellar structures have been produced in ways that are predictable from the pure surfactant-water phase diagrams. The synthesis appears to proceed initially through an induction period characterized by the accumulation of silica-coated spherical micelles near the surface. All syntheses, except those involving C(12)TACl, show a sudden transformation of the spherical micellar phase to a hexagonal phase. This occurs when the gradually increasing ionic strength and/or changing ethanol concentration is sufficient to change the position of boundaries within the phase diagram. A possible mechanism for this to occur may be to induce a sphere to rod transition in the micellar structure. This transformation, as predicted from the surfactant-water phase diagram, can be induced by addition of salts and is slower for chloride than bromide counteranions. The hexagonal materials change in cell dimension as the chain length is changed in a way consistent with theoretical model predictions. All the materials have sufficiently flexible silica frameworks that phase interconversion is observed both from glassy to hexagonal and from hexagonal, to lamellar and vice versa in those surfactant systems where multiple phases are found to exist.

Effect of increased lung expansion on lung growth and development near midgestation in fetal sheep

Obstruction of the fetal trachea is a potent stimulus for fetal lung growth and may have therapeutic potential in human fetuses with lung hypoplasia. However, the effects of increased lung expansion on lung development near midgestation, which is the preferred timing for fetal intervention, have not been well studied. Our aim was to determine the effects of increased lung expansion on lung development at 75-90 d of gestation in fetal sheep. In three groups of fetuses (n = 4 for each), the trachea was occluded for either 10 [10-d tracheal occlusion (TO) group] or 15 d (15-d TO group) or left intact (control fetuses). TO for both 10 and 15 d caused fetal hydrops, resulting in significantly increased fetal body weights. Both periods of TO significantly increased total lung DNA contents from 99.8 +/- 10.1 to 246.0 +/- 5.3 and 246.9 +/- 48.7 mg in 10- and 15-d TO fetuses, respectively. TO for 10 and 15 d also increased airspace diameter, although the percentage of lung occupied by airspace was not increased in 10-d TO fetuses due to large increases in interairway distances; this resulted from a large increase in mesenchymal tissue. The interairway distances at 15 d of TO were reduced compared with the 10-d value but were still similar to 30% larger than control values. We conclude that TO at

Effect of density on spatial distribution, pit formation and pit diameter of Myrmeleon acer Walker, (Neuroptera : Myrmeleontidae): patterns and processes

The effect of increasing population density on the formation of pits, their size and spatial distribution, and on levels of mortality was examined in the antlion Myrmeleon acer Walker. Antlions were kept at densities ranging from 0.4 to 12.8 individuals per 100 cm(2). The distribution of pits was regular or uniform across all densities, but antlions constructed proportionally fewer and smaller pits as density increased. Mortality through cannibalism was very low and only occurred at densities greater than five individuals per 100 cm(2). Antlions in artificially crowded situations frequently relocated their pits and when more space became available, individuals became more dispersed with time. Redistribution of this species results from active avoidance of other antlions and sand throwing associated with pit construction and maintenance, rather than any attempt to optimise prey capture per se.

The effect of arousals during sleep onset on estimates of sleep onset latency

It is well established that insomniacs overestimate sleep-onset latency. Furthermore, there is evidence that brief arousals from sleep may occur more frequently in insomnia. This study examined the hypothesis that brief arousals from sleep influence the perception of sleep-onset latency. An average of four sleep onsets was obtained from each of 20 normal subjects on each of two nonconsecutive, counterbalanced, experimental nights. The experimental nights consisted of a control night (control condition) and a condition in which a moderate respiratory load was applied to increase the frequency of microarousals during sleep onset (mask condition). Subjective estimation of sleep-onset latency and indices of sleep quality were assessed by self-report inventory. Objective measures of sleep-onset latency and microarousals were assessed using polysomnography. Results showed that sleep-onset latency estimates were longer in the mask condition than in the control condition, an effect not reflected in objective sleep-stage scoring of sleep-onset latency. Furthermore, an increase in the frequency of brief arousals from sleep was detected in the mask condition, and this is a possible source for the sleep-onset latency increase perceived by the subjects. Findings are consistent with the concept of a physiological basis for sleep misperception in insomnia.

Concentration-effect relationship of hydroxychloroquine in patients with rheumatoid arthritis - A prospective, dose ranging study

Objective. A 6 month prospective randomized double blind study was conducted to investigate hydroxychloroquine dose concentration-effect relationships in people with rheumatoid arthritis. Methods. Patients were randomized in 2 groups: one group received 200 mg hydroxychloroquine sulfate daily (A) and one group received 400 mg daily (B). Each month, 8 disease variables were assessed, adverse events recorded, and hydroxychloroquine blood concentrations determined. Results. Twenty-three patients were included: 10 in group A and 13 in group B. After 6 months of therapy, a significant improvement in disease activity was noted for 6 criteria with no statistical differences between groups: pain (assessed by a visual analog scale), joint scores (swelling and tenderness), impairment in daily Living activity (18 activities graded 0 to 8), patient assessment of disease state, and erythrocyte sedimentation rate. Hydroxychloroquine steady-state blood concentrations (Month 6) were significantly different between groups (mean +/- SD): 450.6 +/- 285.3 ng/ml (A) vs 870.3 +/- 329.3 ng/ml(B) (p = 0.0001). Steady-state concentrations were correlated with the daily dose (r = 0.63, p = 0.005), the improvement in activity of daily living (r = 0.49, p = 0.03), and the improvement in joint tenderness score (r = 0.47, p = 0.038). Conclusion. The data indicate that hydroxychloroquine is an effective therapy, but there were no further improvements observed in the group receiving 400 mg daily compared to those receiving 200 mg. There were some correlations between hydroxychloroquine steady-state blood concentrations and effects.

The effect of electrode placement in measuring ipsilateral/contralateral segmental bioelectrical impedance

No Abstract

The effect of solidification rate on the structure of magnesium-aluminium eutectic grains

A magnesium-aluminium alloy of eutectic composition was solidified under two different cooling conditions, producing a low and a high growth rate of the eutectic solid-liquid interface. The high growth rate specimen contained smaller eutectic grains and cells, with a smaller interphase spacing compared with the low growth rate specimen. The high growth rate specimen also contained some primary Mg17Al12 dendrites, suggesting that the coupled zone is skewed towards the Mg phase with increased undercooling, A lamellar eutectic morphology was observed in the low growth rate specimen, while the morphology was fibrous in the high growth rate specimen.

Numerical modelling of single-layer folding: clarification of an issue regarding the possible effect of computer codes and the influence of initial irregularities

The influence of initial perturbation geometry and material propel-ties on final fold geometry has been investigated using finite-difference (FLAC) and finite-element (MARC) numerical models. Previous studies using these two different codes reported very different folding behaviour although the material properties, boundary conditions and initial perturbation geometries were similar. The current results establish that the discrepancy was not due to the different computer codes but due to the different strain rates employed in the two previous studies (i.e. 10(-6) s(-1) in the FLAC models and 10(-14) s(-1) in the MARC models). As a result, different parts of the elasto-viscous rheological field were bring investigated. For the same material properties, strain rate and boundary conditions, the present results using the two different codes are consistent. A transition in Folding behaviour, from a situation where the geometry of initial perturbation determines final fold shape to a situation where material properties control the final geometry, is produced using both models. This transition takes place with increasing strain rate, decreasing elastic moduli or increasing viscosity (reflecting in each case the increasing influence of the elastic component in the Maxwell elastoviscous rheology). The transition described here is mechanically feasible but is associated with very high stresses in the competent layer (on the order of GPa), which is improbable under natural conditions. (C) 2000 Elsevier Science Ltd. All rights reserved.

Effect of combined supplementation with vitamin E and alpha-lipoic acid on myocardial performance during in vivo ischaemia-reperfusion

Reactive oxygen species (ROS) contribute significantly to myocardial ischaemia-reperfusion (I-R) injury. Recently the combination of the antioxidants vitamin E (VE) and alpha-lipoic acid (alpha-LA) has been reported to improve cardiac performance and reduce myocardial lipid peroxidation during in vitro I-R. The purpose of these experiments was to investigate the effects of VE and alpha-LA supplementation on cardiac performance, incidence of dysrhythmias and biochemical alterations during an in vivo myocardial I-R insult. Female Sprague-Dawley rats (4-months old) were assigned to one of the two dietary treatments: (1) control diet (CON) or (2) VE and alpha-LA supplementation (ANTIOXID). The CON diet was prepared to meet AIN-93M standards, which contains 75 IU VE kg(-1) diet. The ANTIOXID diet contained 10 000 IU VE kg(-1) diet and 1.65 g alpha-LA kg(-1) diet. After the 14-week feeding period, significant differences (P < 0.05) existed in mean myocardial VE levels between dietary groups. Animals in each experimental group were subjected to an in vivo I-R protocol which included 25 min of left anterior coronary artery occlusion followed by 10 min of reperfusion. No group differences (P > 0.05) existed in cardiac performance (e.g. peak arterial pressure or ventricular work) or the incidence of ventricular dysrhythmias during the I-R protocol. Following I-R, two markers of lipid peroxidation were lower (P < 0.05) in the ANTIOXID animals compared with CON. These data indicate that dietary supplementation of the antioxidants, VE and alpha-LA do not influence cardiac performance or the incidence of dysrhythmias but do decrease lipid peroxidation during in viva I-R in young adult rats.

In vivo measurement of the effect of intra-abdominal pressure on the human spine

In humans, intra-abdominal pressure (IAP) is elevated during many everyday activities. This experiment aimed to investigate the extent to which increased IAP-without concurrent activity of the abdominal or back extensor muscles-produces an extensor torque. With subjects positioned in side lying on a swivel table with its axis at L3, moments about this vertebral level were measured when IAP was transiently increased by electrical stimulation of the diaphragm via the phrenic nerve. There was no electromyographic activity in abdominal and back extensor muscles. When IAP was increased artificially to similar to 15% of the maximum IAP amplitude that could be generated voluntarily with the trunk positioned in flexion, a trunk extensor moment (similar to6 Nm) was recorded. The size of the effect was proportional to the increase in pressure. The extensor moment was consistent with that predicted from a model based on measurements of abdominal cross-sectional area and IAP moment arm. When IAP was momentarily increased while the trunk was flexed passively at a constant velocity, the external torque required to maintain the velocity was increased. These results provide the first in vivo data of the amplitude of extensor moment that is produced by increased IAP. Although the net effect of this extensor torque in functional tasks would be dependent on the muscles used to increase the IAP and their associated flexion torque, the data do provide evidence that IAP contributes, at least in part, to spinal stability. (C) 2001 Elsevier Science Ltd. All rights reserved.