Transient evoked otoacoustic emissions in two-month-old infants: A normative study

Researchers have recently reported the effects of age, sex, ear asymmetry, and subject's activity status on transient evoked otoacoustic emissions (TEOAEs). The present study aimed to expand upon such reports by describing the characteristics of TEOAE spectra obtained from a cohort of 607 two-month-old infants in community child health clinics. Results indicated significant sex, ear and activity state effects on the signal:noise ratio, response. whole wave and band reproducibility values. These findings suggest the need for TEOAE normative data to be expressed as a function of sex, ear, and activity state of infants. These characteristics of TEOAE spectra may shape future investigations into appropriate pass-fail criteria for two-month-old infants.

Transient evoked otoacoustic emissions in 6-year-old school children: a normative study

Great potential has recently been demonstrated for the application of transient evoked otoacoustic emissions (TEOAEs) in screening the hearing of school-aged children. The present study aimed to describe the range of TEOAE values obtained from a large cohort of 6-year-old children in school settings. Results indicated significant sex and ear asymmetry effects on signal-to-noise ratio, response, whole wave reproducibility, band reproducibility and noise levels. A prior history of ear infections was also shown to influence response level, whole wave reproducibility and band reproducibility. The sex, ear and history specific normative data tables derived may contribute to future improvements in the accuracy of hearing screening for 6-year-old school children.

Placental growth hormone (GH), GH-binding protein, and insulin-like growth factor axis in normal, growth-retarded, and diabetic pregnancies: Correlations with fetal growth

We previously described significant changes in GH-binding protein (GHBP) in pathological human pregnancy. There was a substantial elevation of GHBP in cases of noninsulin-dependent diabetes mellitus and a reduction in insulin-dependent diabetes mellitus. GHBP has the potential to modulate the proportion of free placental GH (PGH) and hence the impact on the maternal GH/insulin-like growth factor I (IGF-I) axis, fetal growth, and maternal glycemic status. The present study was undertaken to investigate the relationship among glycemia, GHBP, and PGH during pregnancy and to assess the impact of GHBP on the concentration of free PGH. We have extended the analysis of specimens to include measurements of GHBP, PGH, IGF-I, IGF-II, IGF-binding protein-1 (IGFBP-1), IGFSP-2, and IGFBP-3 and have related these to maternal characteristics, fetal growth, and glycemia. The simultaneous measurement of GHBP and PGH has for the first time allowed calculation of the free component of PGH and correlation of the free component to indexes of fetal growth and other endocrine markers. PGH, free PGH, IGF-I, and IGF-II were substantially decreased in IUGR at 28-30 weeks gestation (K28) and 36-38 weeks gestation (K36). The mean concentration (+/-SEM) of total PGH increased significantly from K28 to K36 (30.0 +/- 2.2 to 50.7 +/- 6.2 ng/mL; n = 40), as did the concentration of free PGH (23.4 +/- 2.3 to 43.7 +/- 6.0 ng/mL; n = 38). The mean percentage of free PGH was significantly less in IUGR than in normal subjects (67% vs. 79%; P < 0.01). Macrosomia was associated with an increase in these parameters that did not reach statistical significance. Multiple regression analysis revealed that PGH/IGF-I and IGFBP-5 account for 40% of the variance in birth weight. IGFBP-3 showed a significant correlation with IGF-I, IGF-II, and free and total PGK at K28 and K36. Noninsulin-dependent diabetes mellitus patients had a lower mean percentage of free PGH (65%; P < 0.01), and insulin-dependent diabetics had a higher mean percentage of free PGH (87%; P < 0.01) than normal subjects. Mean postprandial glucose at K28 correlated positively with PGH and free PGH (consistent with the hyperglycemic action of GH). GHBP correlated negatively with both postprandial and fasting glucose. Although GHBP correlated negatively with PGH (r = -0.52; P

Mortality variation across Australia: descriptive data for States and Territories, and statistical divisions

OBJECTIVE: To describe variation in all cause and selected cause-specific mortality rates across Australia. METHODS: Mortality and population data for 1997 were obtained from the Australian Bureau of Statistics. All cause and selected cause-specific mortality rates were calculated and directly standardised to the 1997 Australian population in 5-year age groups. Selected major causes of death included cancer, coronary artery disease, cerebrovascular disease, diabetes, accidents and suicide. Rates are reported by statistical division, and State and Territory. RESULTS: All cause age-standardised mortality was 6.98 per 1000 in 1997 and this varied 2-fold from a low in the statistical division of Pilbara, Western Australia (5.78, 95% confidence interval 5.06-6.56), to a high in Northern Territory-excluding Darwin (11.30, 10.67-11.98). Similar mortality variation (all p<0.0001) exists for cancer (1.01-2.23 per 1000) and coronary artery disease (0.99-2.23 per 1000), the two biggest killers. Larger variation (all p<0.0001) exists for cerebrovascular disease (0.7-11.8 per 10,000), diabetes (0.7-6.9 per 10,000), accidents (1.7-7.2 per 10,000) and suicide (0.6-3.8 per 10,000). Less marked variation was observed when analysed by State and Territory. but Northern Territory consistently has the highest age-standardised mortality rates. CONCLUSIONS: Analysed by statistical division, substantial mortality gradients exist across Australia, suggesting an inequitable distribution of the determinants of health. Further research is required to better understand this heterogeneity.

Inactive free : total prostate specific antigen ratios in ejaculate from men with suspected and known prostate cancer, compared with young control men

Objective To measure free:total prostate specific antigen (PSA) ratios in ejaculate from men with suspected and known prostate cancer, and in young control men, to determine if this ratio might be useful in discriminating benign from malignant prostatic conditions. Patients, subjects and methods Forty-seven men with prostate cancer (positive biopsies), 52 men with suspected prostate cancer but who had negative biopsies and 28 young men (< 30 years old) and with no family history of cancer, provided either a single ejaculate specimen (total 59) or multiple specimens (total 193) on subsequent occasions. Free and total PSA were measured using appropriate assays. All specimens were diluted in a PSA-negative female serum pool. Results The median free:total PSA ratios were 0.76-0.81 among the patient groups and control men, and there was no statistical difference between the groups. These data presumably only reflect the inactive component of free PSA, given that any alpha(2)-macroglobulin or alpha(1)-antichymotrypsin in the assay serum diluent was likely to have bound the active free PSA component in these samples. Similar results were obtained from those providing single and multiple samples, suggesting that a single specimen is sufficient to reflect the seminal plasma free:total PSA ratio over that period. There was no relationship between seminal plasma free:total PSA ratio and age for the controls or the positive biopsy group, although there was a negative relationship (i.e. a decline with age) that almost reached significance in those with negative biopsies (P = 0.058, R-2 = 0.07). Conclusions This is the first report of free:total PSA ratios in the ejaculate of men with suspected and known prostate cancer compared with young control men. Although no significant changes were detected in the free:total PSA ratios in ejaculate, these results may be confounded by differences in ratios with age, as is the case for serum PSA or different molecular forms of PSA. Indeed, these data suggest that a large proportion of free PSA in seminal plasma may be inactive. Further studies are needed to determine the potential utility of measuring free:total PSA, or other candidate markers, in ejaculate to better discriminate benign from malignant prostate disease.

ERP 'old/new' effects: memory strength and decisional factor(s)

Event-related potentials (ERPs) were recorded while subjects made old/new recognition judgments on new unstudied words and old words which had been presented at study either once ('weak') or three times ('strong'). The probability of an 'old' response was significantly higher for strong than weak words and significantly higher for weak than new words. Comparisons were made initially between ERPs to new, weak and strong words, and subsequently between ERPs associated with six strength-by-response conditions. The N400 component was found to be modulated by memory trace strength in a graded manner. Its amplitude was most negative in new word ERPs and most positive in strong word ERPs. This 'N400 strength effect' was largest at the left parietal electrode (in ear-referenced ERPs). The amplitude of the late positive complex (LPC) effect was sensitive to decision accuracy (and perhaps confidence). Its amplitude was larger in ERPs evoked by words attracting correct versus incorrect recognition decisions. The LPC effect had a left > right, centro-parietal scalp topography (in ear-referenced ERPs). Hence, whereas, the majority of previous ERP studies of episodic recognition have interpreted results from the perspective of dual-process models, we provide alternative interpretations of N400 and LPC old/new effects in terms of memory strength and decisional factor(s). (C) 2002 Elsevier Science Ltd. All rights reserved.

Sequence analysis, chromosomal distribution and long-range organization show that rapid turnover of new and old pBuM satellite DNA repeats leads to different patterns of variation in seven species of the Drosophila buzzatii cluster

We aimed to study patterns of variation and factors influencing the evolutionary dynamics of a satellite DNA, pBuM, in all seven Drosophila species from the buzzatii cluster (repleta group). We analyzed 117 alpha pBuM-1 (monomer length 190 bp) and 119 composite alpha/beta (370 bp) pBuM-2 repeats and determined the chromosome location and long-range organization on DNA fibers of major sequence variants. Such combined methodologies in the study of satDNAs have been used in very few organisms. In most species, concerted evolution is linked to high copy number of pBuM repeats. Species presenting low-abundance and scattered distributed pBuM repeats did not undergo concerted evolution and maintained part of the ancestral inter-repeat variability. The alpha and alpha/beta repeats colocalized in heterochromatic regions and were distributed on multiple chromosomes, with notable differences between species. High-resolution FISH revealed array sizes of a few kilobases to over 0.7 Mb and mutual arrangements of alpha and alpha/beta repeats along the same DNA fibers, but with considerable changes in the amount of each variant across species. From sequence, chromosomal and phylogenetic data, we could infer that homogenization and amplification events involved both new and ancestral pBuM variants. Altogether, the data on the structure and organization of the pBuM satDNA give insights into genome evolution including mechanisms that contribute to concerted evolution and diversification.

Fragmentation of a Neotropical migratory fish population by a century-old dam

Loss of connectivity in impounded rivers is among the impacts imposed by dams, and mitigation measures such as fish passages might not accomplish their purpose of reestablishing an efficient bi-directional gene flow in the fish populations affected. As a consequence, fish populations remain fragmented, and a new interpopulational structure may develop, with increased risk of reduced genetic diversity and stochastic extinction. In order to evaluate the effects of the Gavio Peixoto Dam, which was constructed almost a century ago on the Jacar,-Gua double dagger u River in the Upper Parana River basin, Brazil, a comparative morphometric study was undertaken on the populations of the Neotropical migratory characid fish Salminus hilarii living up- and downstream of this dam. Population dynamics, spatial segregation, and habitat use by different age classes were monitored for 2 years. We found that segregation caused by the dam and long periods with no efficient connection by fish passages have led to fragmentation and interpopulational structuring of S. hilarii, as revealed by canonical variable analysis of morphometric features. The fish populations occupying the up- and downstream sections have succeeded in performing short-distance reproductive migrations in the main river and tributaries, have found suitable habitats for completing their life cycle, and have been able to maintain distinct small-sized populations so far.

A non-invasive method for silencing gene transcription in honeybees maintained under natural conditions

in the Apis mellifera post-genomic era, RNAi protocols have been used in functional approaches. However, sample manipulation and invasive methods such as injection of double-stranded RNA (dsRNA) can compromise physiology and survival. To circumvent these problems, we developed a non-invasive method for honeybee gene knockdown, using a well-established vitellogenin RNAi system as a model. Second instar larvae received dsRNA for vitellogenin (dsVg-RNA) in their natural diet. For exogenous control, larvae received dsRNA for GFP (dsGFP-RNA). Untreated larvae formed another control group. Around 60% of the treated larvae naturally developed until adult emergence when 0.5 mu g of dsVg-RNA or dsGFP-RNA was offered while no larvae that received 3.0 mu g of dsRNA reached pupal stages. Diet dilution did not affect the removal rates. Viability depends not only on the delivered doses but also on the internal conditions of colonies. The weight of treated and untreated groups showed no statistical differences. This showed that RNAi ingestion did not elicit drastic collateral effects. Approximately 90% of vitellogenin transcripts from 7-day-old workers were silenced compared to controls. A large number of samples are handled in a relatively short time and smaller quantities of RNAi molecules are used compared to invasive methods. These advantages culminate in a versatile and a cost-effective approach. (c) 2008 Elsevier Ltd. All rights reserved.

A Statistical Study of the Association of Seven Dental Anomalies in the Brazilian Population

The objective of this study was to show the association patterns among seven types of dental anomalies (second pre-molar agenesis, upper side incisive reduced in size, lower first molar infra-ochlesis, enamel hypoplasia, first molar ectopic eruption, supra numerous teeth and upper canine ectopic eruption) in a population sample without dental treatment ranging in age from 7 to 14. A total of 172 patients were attended and underwent the clinical examination at the Clinica Infantil da Fundacao Educacional de Barretos. Eleven patients from this total were selected according to a first dental anomaly diagnosis and submitted to panoramic radiography. A significant association (p < 0.05) was detected among six pairs of anomalies (second pre-molar agenesis x first pre-molar ectopic eruption; second pre-molar agenesis x lower first molar infra-ochlesis; second pre-molar agenesis x upper side incisive reduced in size; supra numerous teeth x reduced size upper side incisive; first pre-molar ectopic eruption x enamel hypoplasia; lower first molar infra-ochlesis x upper side incisive reduced in size) suggesting a common genetic origin for these conditions. The association was not significant in only one case where there was anomaly sharing by the patients. The existence of an anomaly is clinically relevant for early diagnosis of a possible association and an anomaly can indicate an increased risk of other anomalies.

Why fear snakes and spiders? Evidence for a learning-based account of fear-relevant stimulus-processing

Fear-relevant stimuli, such as snakes, spiders and heights, preferentially capture attention as compared to nonfear-relevant stimuli. This is said to reflect an encapsulated mechanism whereby attention is captured by the simple perceptual features of stimuli that have evolutionary significance. Research, using pictures of snakes and spiders, has found some support for this account; however, participants may have had prior fear of snakes and spiders that influenced results. The current research compared responses of snake and spider experts who had little fear of snakes and spiders, and control participants across a series of affective priming and visual search tasks. Experts discriminated between dangerous and nondangerous snakes and spiders, and expert responses to pictures of nondangerous snakes and spiders differed from those of control participants. The current results dispute that stimulus fear relevance is based purely on perceptual features, and provides support for the role of learning and experience.

Statistical questions - Comment

No Abstract

Comparison of videolaparoscopic versus open surgery for benign renal diseases in children

Introduction: Laparoscopic nephrectomy in children has become a reasonable alternative to open nephrectomy and has replaced open surgery for many renal diseases. The purpose of our study is to evaluate transperitoneal videolaparoscopic procedures in renal benign diseases in comparison to an open surgery approach. Patients and methods: 34 children aged between 17 days and 15 years old (mean 6.14) were divided into two groups in order to be submitted to nephrectomy. The first one underwent transperitoneal videolaparoscopic nephrectomy and was composed by 21 patients aged from 2 months to 15 years (mean 7.42), from which 12 were females and 9 males. The second group was submitted to open nephrectomy and was composed by 13 patients aged from 17 days to 11 years (mean 3.91), 6 females and 7 males. The groups were compared regarding anesthesic time, operative time, length of hospital stay, postoperative pain and time of reintroduction of oral intake. Short and long term complications were also evaluated. Statistical analysis was performed by Student t-test with the level of significance set at P < 0.05. The study was previously approved by the Committee on Ethics in Research of our institution. Results: Significant statistical difference was observed only for the variable length of hospital stay. No laparoscopy group case was converted to open surgery. There was no immediate or late complication. Blood loss was negligible and no transfusion was required. Conclusions: In our experience, transperitoneal videolaparoscopic nephrectomy has similar results to open nephrectomy, except for time of hospitalization. (C) 2009 AEU. Published by Elsevier Espana, S.L. All rights reserved.