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H Davis

Publications and source records attributed to H Davis.

285 records · Page 16Linked to original sources
PubMedDate not supplied

A slow brain stem response for low-frequency audiometry.

Proper choices of stimuli and of brain stem electric responses allow us to estimate peripheral auditory thresholds at 500, 1 000, 2 000 and 4 000 Hz with an accuracy of about +/- 10 dB. With the help of sedation (secobarbital), such audiograms may be obtained from each ear of a child of any age in a single session. Tone pips (filtered clicks) or very brief tone bursts give a frequency selectivity that is clinically adequate. The rise time must be adjusted to the center frequency. A rise time of two periods with a plateau from zero to one period gives a good compromise between frequency specificity and a synchronous neural discharge. The best threshold indicator for tone pips of 2 000 Hz or higher (or unfiltered clicks) is P6 (Jewett V). At 60 dB nHL its latency is 6.0-7.0 ms (for children of 1 year or older), but near threshold it is 8.0-9.5 ms. An input pass-band of 140-3 000 Hz is appropriate. The best threshold indicator at 500 or 1 000 Hz is a nearly neglected slower wave with a scalp-negative crest at about 10 ms following a 60-dB click. Latency is 15 ms following a 500-Hz tone pip at 15 dB SL. We call this wave "slow negative (ten)" or SN10. To see it well a wider input pass-band such as 40-3 000 Hz is needed. SN10 is usually obscured by P6 or by frequency-following response at stimulus levels above 35 dB SL. The details are given of a clinical routine that allows the determination (+/- 10 dB) of 8 threshold endpoints within about 80 min. Several precautions and limitations are discussed, and also the origin of the SN10 wave.

Audiometry↗
PubMedDate not supplied

Psychosocial implications of strabismus surgery in adults.

PURPOSE: Adults with socially noticeable strabismus have been known to experience psychosocial difficulties as a result of their abnormal eye position. This study was designed to assess the impact of noticeable strabismus in adults and the psychosocial effects of surgical correction. METHODS: A total of 31 adults who underwent surgery for longstanding horizontal strabismus where poor alignment was the primary reason for consenting to surgery were requested to complete a self-reporting repertory grid to appraise the psychosocial consequences of corrective strabismus surgery. RESULTS: Prior to corrective surgery, the majority of subjects reported various psychosocial difficulties, considered by them to be wholly or partly due to their unsightly strabismus. A significant improvement in interpersonal interactions is apparent following strabismus surgery. CONCLUSION: Surgery to improve ocular alignment appears to herald major improvements in the quality of psychosocial functioning for the majority of adults undergoing such surgical procedures (P < 0.001).

Adolescent↗
PubMedDate not supplied

A novel skin penetration enhancer: evaluation by membrane diffusion and confocal microscopy.

PURPOSE: The aim of this study was to determine the in vitro transdermal efficacy of a Meyer Zall Laboratories (MZL) oil/water emulsion in two separate preparations containing the actives, coal tar and the non-steroidal anti-inflammatory drug, diclofenac sodium. METHOD: The release rate of the two active ingredients from MZL dermatological preparations, Exorex and Athru-Derm and four comparator products was determined using an enhancer cell system, whilst specific penetration characteristics of the MZL formulation were elucidated using confocal and electron microscopy. The latter properties were explored at both the organ level, using human skin, as well as at a cellular level using a melanoma cell line. RESULTS: While the in vitro release rates for all formulations was high, coal tar and diclofenac release from Exorex and Athru-Derm respectively was, at nearly all time intervals, significantly higher than from comparator products. Microscopy revealed the presence of spherical liposomal type structures in both the MZL lotion and a comparator gel. In the MZL lotion, the majority of these structures, referred to here as emzaloid particles, were in the order of magnitude of about 50 nm to 1 microm in diameter with a small minority exceeding these dimensions. After application of Athru-Derm to human skin, intact emzaloid particles of submicron dimensions were detected in the epidermis in association with the cell membranes. The affinity of the MZL lotion for cell membranes was further demonstrated with melanoma cells; in addition, the formulation was seen to penetrate even to the nucleus of viable cells. CONCLUSION: Overall the data suggest that the oil/water base in MZL formulations is a highly efficient transdermal vehicle able to transport a wide range of indication- specific actives to their site of action.

Administration, Topical↗
PubMedDate not supplied

Buspirone effect on tobacco withdrawal symptoms: a randomized placebo-controlled trial.

BACKGROUND: Withdrawal symptoms hinder smoking cessation in nicotine-dependent smokers. This prospective, double-blind, placebo-controlled clinical trial was conducted to evaluate buspirone for nicotine withdrawal symptoms. METHODS: Fifty-four heavy smokers (mean 33.1 cigarettes per day for 24 years) were randomly prescribed 30 mg/d of buspirone or placebo beginning 3 weeks before abrupt smoking cessation. Validated nicotine withdrawal and anxiety scales were administered at baseline and serially for 2 weeks after cessation. RESULTS: Baseline demographic and nicotine-dependence measures were similar for each group. Three smokers (1 on buspirone, 2 on placebo) dropped out of the protocol prior to the quit date. Both groups had significant withdrawal effects over time (analysis of variance [ANOVA] P = 0.0001). There was a significant buspirone effect on any nicotine withdrawal symptoms (ANOVA, alpha = 0.05). Smokers who relapsed, regardless of group, reported significantly worse craving, irritability, anxiety, and difficulty concentrating than abstainers (P less than 0.05). Relapse rates at follow-up visits were not significantly different between groups. Two-week abstinence rates were 52 percent for placebo and 62 percent for buspirone (chi-square, P = 0.760). CONCLUSIONS: In these heavy smokers, buspirone offered no relief from nicotine withdrawal symptoms. Regardless of treatment, relapsing smokers experienced more intense nicotine withdrawal.

Adolescent↗
PubMedDate not supplied

Disposable hydrogel contact lenses for extended wear.

Nine ophthalmologists and nine optometrists conducted a premarket study of the Acuvue disposable contact lens manufactured by Vistakon, Inc. Of the 812 patients offered the lens, 733 accepted it and were enrolled in the study. These patients were fitted with the lens and followed for a period of 8 months. Over 98% of these patients had 20/25 or better vision on initial fitting; and subjective ratings of lens comfort were very good. Only 3.7% (27 of 733) discontinued wearing their lenses during the study period. Thirty-four patients (5.6%) experienced a problem while wearing their contact lenses.

Adolescent↗
PubMedDate not supplied

Give us democracy.

Explore the source record for details and available documents.

Humans↗
PubMedDate not supplied

Nutrition counseling--should physicians guide their patients?

This article summarizes the findings of a study initiative under-taken by the U.S. Public Health Service to examine its own role in fostering a more effective education of U.S. physicians in nutrition. The study was completed in response to a congressional request that the federal government examine the need for a more productive government role in this important area. The literature, dating back to the turn of the century, is relatively uniform in its conclusions that U.S. physicians are woefully undertrained in nutrition. The training inadequacy might be dismissed, indeed, has been dismissed by many programs, yet the role of nutrition in promoting health becomes clearer with each passing year. We ask: Will either the government or the medical education community begin to equip our physicians with the knowledge needed to bring nutrition into play as an active therapeutic approach to complement other therapies?

Clinical Competence↗
PubMedDate not supplied

Cost of hospitalizations associated with sickle cell disease in the United States.

OBJECTIVE: This study estimated the number and cost of hospitalizations associated with sickle cell disease in the United States. METHODS: To estimate the number of hospitalizations per year in the United States of people with sickle cell disease, the authors used data for the years 1989 through 1993 from national hospital discharge surveys conducted by the National Center for Health Statistics. The authors derived cost estimates using data from a 1992 national hospital discharge survey conducted by the Agency for Health Care Policy and Research and a 1992 survey of physicians conducted by the American Medical Association. RESULTS: During the years 1989 through 1993, there were on average an estimated 75,000 hospitalizations per year of children and adults with sickle cell disease. The average direct cost per hospitalization (in 1996 dollars) was estimated at $6300, for a total direct cost of $475 million per year. In 66% of hospital discharge records, government programs were listed as the expected principal source of payment. CONCLUSIONS: The cost of hospitalizations associated with sickle cell disease is substantial. Because government programs pay most of this cost, further government-funded research to develop interventions that prevent complications of the disease has great potential for cost savings as well as for reducing the suffering of those afflicted with this painful genetic disorder. These national cost estimates contribute to an understanding of the impact of sickle cell disease and should be useful in establishing research priorities.

Adolescent↗
PubMedDate not supplied

Geographic differences in mortality of young children with sickle cell disease in the United States.

OBJECTIVES: Because geographic differences in health care have been found for many diseases, including those affecting children, there are probably geographic differences in the health care of young children with sickle cell disease. Consequently, survival of young children with sickle cell disease might differ among geographic areas. This study's objective was to identify areas in the United States where young children with sickle cell disease are at especially high and low risk of dying. METHODS: Using U.S. death certificate data from 1968 through 1992, the authors calculated the mortality rates of 1- through 4-year-old black children with sickle cell disease for states, counties, and cities. Deaths from trauma, congenital anomalies, and perinatal conditions were excluded. RESULTS: From 1968 through 1980 and from 1981 through 1992, 1- through 4-year-old black children with sickle cell disease in Florida had a markedly higher risk of dying, and those in Pennsylvania had a markedly lower risk of dying, than the average 1- through 4-year-old black child with the disease in the United States. From 1981 through 1992, 1- through 4-year-old black children with sickle cell disease in Maryland had the lowest mortality rate in the nation. During the same time period, 1- through 4-year-old black children with sickle cell disease in five counties in Florida were at especially high risk, while in Baltimore no young black children with the disease died. These geographic differences in mortality of black children with sickle cell disease greatly exceeded geographic differences in mortality of black children without the disease. CONCLUSIONS: Marked differences exist across the United States in mortality of young black children with sickle cell disease. To improve survival for children with the disease in high mortality areas, evaluations should be made of the accessibility and quality of medical care, and of parents' health care seeking behavior and compliance with antibiotic prophylaxis. In addition, efforts should be made to understand and duplicate the success of treatment programs in low mortality areas.

Anemia, Sickle Cell↗