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R A Nelson

Publications and source records attributed to R A Nelson.

195 records · Page 11Linked to original sources
PubMedDate not supplied

Mitochondrial gene mutation is a significant predisposing factor in aminoglycoside ototoxicity.

PURPOSE: Aminoglycoside-induced deafness caused by mutations in the mitochondrial 12S ribosomal RNA gene has been described in a number of Asian patients. The purpose of the current study is to analyze ethnically diverse patients in the United States with hearing loss after aminoglycoside exposure for presence or absence of these mitochondrial DNA mutations, and establish the frequency and clinical presentation associated with them. PATIENTS AND METHODS: Clinical histories, medical records, and blood samples were obtained from 41 unrelated American individuals with hearing loss after aminoglycoside exposure. DNA was extracted from the blood of these individuals, amplified by the polymerase chain reaction, and analyzed for mitochondrial ribosomal RNA gene mutations by allele-specific oligonucleotide hybridization, restriction fragment length polymorphism analysis, and sequencing. RESULTS: The nucleotide 1555 A-->G mutation was identified in 7 of 41 individuals (17%). None of the other known mutations was found. The ethnic origin of the individuals with predisposing mutations included Caucasians, Hispanics, and Asians. Four of the 7 patients with the 1555 A-->G mutation had a family history of aminoglycoside-induced ototoxicity. Particularly unexpected was the late onset of hearing loss in 3 of these patients, years after the aminoglycoside exposure. The 12S ribosomal RNA gene was sequenced in these patients, and a second sequence change that could be responsible for the milder phenotype was detected in 1 of the 3 patients. CONCLUSION: These findings imply that a significant proportion of patients with aminoglycoside-induced ototoxicity harbor mutations in the 12S rRNA gene, which can be detected by DNA screening. Also, the majority of these hearing losses could have been easily prevented by the simple taking of a clinical history. In these individuals, a genetic susceptibility to the ototoxic effects of aminoglycosides can be diagnosed, and deafness can be prevented in maternal relatives by avoidance of these antibiotics.

Adult↗
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Acute mouse and chronic dog toxicity studies of danthron, dioctyl sodium sulfosuccinate, poloxalkol and combinations.

Because of an apparent typographic error in a US patent, there has been some confusion as to the acute oral toxicity of danthron and danthron in combination with dioctyl sodium sulfosuccinate (DSS). Acute oral toxicity studies in mice revealed LD50 values of greater than 7 gm/kg for danthron, 2.64 gm/kg for DSS and 3.42 gm/kg for danthron/DSS mixture (1:2 ratio). These results indicate that the lethality of these compounds is in the gm/kg range and not in the mg/kg range. A one year chronic toxicity study of danthron, dioctyl sodium sulfosuccinate, poloxalkol and combinations in dogs failed to reveal any toxic effects. In particular, there was no evidence of hepatotoxicity or of any changes in the myenteric plexuses in the chronically treated dogs.

Animals↗
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Knowing what we mean by wanting autonomy.

Central to decisions regarding merging your medical group into another organization is the concern for loss of autonomy. Merging the vehicle from which the physician's livelihood is derived demands careful consideration and clear understanding of what will be gained and what will be lost. In the marriage of any two parties, whether individuals or businesses, some autonomy must be forfeited or the marriage won't work. Understanding what autonomy means to the individuals or businesses is essential before the forfeiture of any autonomy can be assessed. The author suggests autonomy can be defined in three levels, each building on the one before and each carrying different levels of importance to those considering a marriage or merger with another. Understanding these levels, and what importance one places on each, will make the decision process easier to address by both parties in the merger.

California↗
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What is the payoff in computerized appointment scheduling?

Is your group experiencing difficulty in the area of patient appointment scheduling? By changing from a manual method to a system of on-line computerized appointment scheduling, you will not only realize the value of consistent scheduling, but also the benefits of credit control and a reduction of time-consuming error correction. The process that this group went through in developing a computerized system to meet their specific needs is especially relevant to larger group practices. However, there are systems available that can fulfill the needs of any size group.

Appointments and Schedules↗
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Managing the complexities of group practice. An interview with ACMPE president Robert Nelson.

Robert A. Nelson, FACMPE, the new president of the American College of Medical Practice Executives (ACMPE) and a principal with the Canon Group, Santa Barbara, Calif., took time to share his vision of the ACMPE and the state of group practice with the MGM Journal. A past president of MGMA. Nelson was honored in 1999 with the ACMPE's Harry J. Harwick Award--the College's highest recognition for health care executives.

Attitude of Health Personnel↗