Effect of slow-acting wide dynamic range compression on measures of intelligibility and ratings of speech quality in simulated-loss listeners.

The purpose of this study was twofold: (a) to determine the extent to which 4-channel, slow-acting wide dynamic range amplitude compression (WDRC) can counteract the perceptual effects of reduced auditory dynamic range and (b) to examine the relation between objective measures of speech intelligibility and categorical ratings of speech quality for sentences processed with slow-acting WDRC. Multiband expansion was used to simulate the effects of elevated thresholds and loudness recruitment in normal hearing listeners. While some previous studies have shown that WDRC can improve both speech intelligibility and quality, others have found no benefit. The current experiment shows that moderate amounts of compression can provide a small but significant improvement in speech intelligibility, relative to linear amplification, for simulated-loss listeners with small dynamic ranges (i.e., flat, moderate hearing loss). This benefit was found for speech at conversational levels, both in quiet and in a background of babble. Simulated-loss listeners with large dynamic ranges (i.e., sloping, mild-to-moderate hearing loss) did not show any improvement. Comparison of speech intelligibility scores and subjective ratings of intelligibility showed that listeners with simulated hearing loss could accurately judge the overall intelligibility of speech. However, in all listeners, ratings of pleasantness decreased as the compression ratio increased. These findings suggest that subjective measures of speech quality should be used in conjunction with either objective or subjective measures of speech intelligibility to ensure that participant-selected hearing aid parameters optimize both comfort and intelligibility.     

Estrogen receptor-mediated down-regulation of corticotropin-releasing hormone gene expression is dependent on a cyclic adenosine 3＇ ,5＇-monophosphate regulatory element in human placental syncytiotrophoblast cells

Placental CRH plays a major role in the mechanisms controlling human pregnancy and parturition. Understanding how placental CRH production is regulated is therefore of importance. Previously we have shown that placental expression of CRH peptide and mRNA are inhibited by estrogens, in contrast to the stimulatory effects of estrogen on hypothalamic CRH production. Our current study found that in placental cells cotransfected with a CRH promoter construct and an estrogen receptor-alpha expression vector results in a differential regulation whereby 17beta estradiol (E2) decreased and the putative pure estrogen antagonist, ICI 182780,     

Less severe retinopathy of prematurity induced by surfactant replacement therapy

To assess the effect of surfactant replacement therapy (SRT) on the prevalence and severity of retinopathy of prematurity (ROP), we compared data from 160 SRT-treated preterm infants with data from 230 historic controls. The prevalence of ROP was 30.6% in the treatment group and 23.4% in the control group. Severe ROP (stages 3-4) was seen in 6.1% of the infants with ROP in the treatment group and 20.3% of the ROP patients in the control group. Surfactant therapy had no influence on the prevalence of ROP (odds ratio 1.4, 95% confidence interval 0.797-2.459, p = 0.242). However, SRT was associated with a decreased risk for severe ROP, compared to mild ROP (odds ratio 0.226, 95% confidence interval 0.056-0.905, p = 0.036). These data suggest that SRT is associated with a decreased risk for severe ROP.     

Polyarteritis nodosa in children: radiological aspects and diagnostic correlation

The radiological findings in 14 children with polyarteritis nodosa (PN) were evaluated in relation to clinical, laboratory, and histological findings. In this series, there were two major groups of radiological findings, one associated with renal insufficiency and the other with intestinal vascular insufficiency. No radiographic finding was pathognomonic. Two patients were suspected of having small bowel intussusception (SBI), and SBI was documented at laparotomy in a third patient. The diagnosis and management of PN in children is dependent upon the correlation of clinical and laboratory findings. Associated pertinent radiological features which may be useful in the management of children with PN are reviewed.     

Aggressive pharmacologic donor management results in more transplanted organs

BACKGROUND: Brain death results in adverse pathophysiologic effects in many cadaveric donors, resulting in cardiovascular instability and poor organ perfusion. Hormonal resuscitation (HR) has been reported to stabilize and improve cardiac function in brain-dead donors. The goal of this study was to examine the effect of HR on the brain-dead donor on the number of organs transplanted per donor. METHODS: A retrospective analysis of all brain-dead donors recovered in the United States from January 1, 2000, to September 30, 2001, was conducted. HR consisted of a methylprednisolone bolus and infusions of vasopressin and either triiodothyronine or L-thyroxine. Univariate analyses and multivariate logistic regression analyses were used to detect differences between the HR group and those donors who did not receive HR. RESULTS: Of 10,292 consecutive brain-dead donors analyzed, 701 received three-drug HR. Univariate analysis showed the mean number of organs from HR donors (3.8) was 22.5% greater than that from nonhormonal resuscitation donors (3.1) (P <0.001). Multivariate analyses showed that HR was associated with the following statistically significant increased probabilities of an organ being transplanted from a donor: kidney 7.3%, heart 4.7%, liver 4.9%, lung 2.8%, and pancreas 6.0%. Extrapolation of these probabilities to the 5,921 brain-dead donors recovered in 2001 was calculated to yield a total increase of 2,053 organs. CONCLUSION: HR stabilizes certain brain-dead donors and is associated with significant increases in organs transplanted per donor.     

Accuracy of fetal echocardiography

The reliability of prenatal ultrasound (US) for the detection of structural heart defects was investigated in a consecutive population of patients referred for prenatal US. Twenty-eight of 49 fetuses (57%) shown to have one or more heart defects with physical examination or autopsy were found to have congenital heart disease with prenatal US. There were 66 cardiac defects in 49 fetuses, 33 of which were entirely or partly identified (50%). Defects correctly diagnosed included hypoplasia of either ventricle, common atrioventricular canal, tetralogy of Fallot, transposition of the great vessels, and Ebstein anomaly. Defects rarely diagnosed correctly included semilunar valve stenosis, total anomalous pulmonary venous drainage, coarctation of the aorta, pulmonic atresia, atrioseptal defect, and ventricular septal defect. Many types of heart defects can be diagnosed accurately with prenatal US in a general population of patients not at high risk for congenital heart disease. Some lesions, however, were difficult to detect.     

Identification of a second human nm23 gene, nm23-H2

Reduced RNA and/or protein levels corresponding to the murine nm23-1 and human nm23-H1 complementary DNA clones have been correlated with high tumor metastatic potential in several rodent model systems and human breast carcinomas. We report the identification of a second human nm23 gene, designated nm23-H2. The pNM23-H2S complementary DNA clone predicted a Mr 17,000 protein 88% identical to nm23-H1. nm23-H2 also shared a significant homology with nucleoside diphosphate kinases and a Drosophila developmental gene. Southern blots containing BglII-restricted genomic DNA, which exhibited an allelic restriction fragment length polymorphism for nm23-H1, contained nonallelic bands upon rehybridization to the nm23-H2 probe. Thus, nm23-H1 and nm23-H2 are distinct genes. Northern blot hybridization of nm23-H1- and nm23-H2-specific probes to breast tumors and cell lines indicated that nm23-H1 expression was reduced in high metastatic potential tumor cells to a greater extent than nm23-H2. The data indicate the existence of a family of independently regulated nm23 genes.