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Biomedical subjects

W Logan

Publications and source records attributed to W Logan.

At least 19 recordsLinked to original sources
PubMed1986

Visual and auditory neurotoxicity in patients receiving subcutaneous deferoxamine infusions.

Of 89 patients receiving nightly subcutaneous deferoxamine for transfusion-dependent thalassemia major or Diamond-Blackfan anemia, 13 presented with visual loss or deafness of acute onset or both. Detailed ophthalmologic, audiologic, and evoked-potential studies uncovered abnormalities caused by neurotoxicity in 27 more. Four patients with visual loss had optic neuropathy, with a marked decrease in acuity, loss of color vision, and delayed visual evoked potentials. Five asymptomatic patients had changes in the pigment of the retinal epithelium. The hearing loss was characterized by a high-frequency sensorineural deficit, which necessitated hearing aids in six patients. When deferoxamine was stopped, recovery of vision was complete in 2 patients and partial in 2, and in 22 patients with abnormal audiograms, reversal of the hearing deficit was complete in 4 and partial in 1. An analysis of the clinical data showed that members of the affected group were younger, had lower serum ferritin values, and were self-administering higher doses of deferoxamine per kilogram of body weight. Significantly lower doses of deferoxamine were being taken by patients without abnormalities than by those with visual symptoms, abnormal audiograms, or prolonged evoked potentials (P less than 0.001, less than 0.006, and less than 0.04, respectively). The data implicate high-dose deferoxamine as a central factor in the pathogenesis of the neurotoxicity. We strongly recommend careful regulation of the deferoxamine dosage and serial audiovisual monitoring in all patients receiving the drug.

Adolescent↗
PubMed1984

Carotid and coronary arterial disease. A rational approach.

One hundred thirty-four patients referred for myocardial revascularization had oculoplethysmography/carotid phonoangiography (OPG/CPA) evaluations as a screening test for possible carotid arterial disease. On the basis of preoperative neurologic symptoms or hemodynamically positive OPG/CPA studies, 52 patients had carotid arteriography. Forty-six patients with coexistent carotid and coronary arterial occlusive disease were identified. Twenty-nine had a previous history of central nervous system (CNS) dysfunction, while ten patients (20%) were asymptomatic. Twenty-two patients had "staged" coronary artery bypass grafts (CABG) and carotid endarterectomy (CE) procedures, while 24 had simultaneous CABG/CE. Of the staged patients, one fatal myocardial infarction occurred after CE but prior to CABG; two patients experienced neurologic deficits after CABG yet prior to CE. Twenty-four patients had simultaneous CE/CABG, and no cardiac or neurologic complications occurred. All patients undergoing cardiovascular surgery should have preoperative noninvasive carotid screening studies performed. If OPG/CPA studies indicate a hemodynamically significant lesion, arteriography is indicated. When OPG/CPA studies are negative, yet a history consistent with previous CNS dysfunction is present, a digital intravenous arteriogram is performed. In the presence of coexistence severe coronary and extracranial carotid stenotic or ulcerative plaque disease, simultaneous CE/CABG is advocated.

Arterial Occlusive Diseases↗
PubMed1983

Methylphenidate hydrochloride given with or before breakfast: II. Effects on plasma concentration of methylphenidate and ritalinic acid.

Methylphenidate HCl (Ritalin) is often prescribed for the treatment of hyperactivity and is usually administered orally 30 minutes to 1 hour before meals, based on an assumption that meals may interfere with the absorption or metabolism of the drug. Seven boys who were taking methylphenidate regularly for the treatment of hyperactivity were hospitalized and given their established dose of the drug intravenously or orally, either with breakfast or in a fasted state. Blood samples were taken to determine the pharmacokinetics of the drug in each condition. Few differences between the "fed" and "fasted" states were noted, but the statistically significant differences indicated that meals accelerate rather than impede the absorption of methylphenidate.

Adolescent↗
PubMed1982

Screening for breast cancer in a high-risk series.

A unique cohort of women at increased risk of breast cancer because of prior X-ray treatment of acute mastitis and their selected high-risk siblings were offered periodic breast cancer screening including physical examination of the breasts, mammography, and thermography. Twelve breast cancers were detected when fewer than four would have been expected based on age-specific breast cancer detection rates from the National Cancer Institute/American Cancer Society Breast Cancer Demonstration Detection Projects. Mammography was positive in all cases but physical examination was positive in only three cases. Thermography was an unreliable indicator of disease. Given the concern over radiation-induced risk, use of low-dose technique and of criteria for participation that select women at high risk of breast cancer will maximize the benefit/risk ratio for mammography screening.

Adult↗