Search PubMed⌕ Search

Biomedical subjects

M Beasley

Publications and source records attributed to M Beasley.

At least 19 recordsLinked to original sources
PubMed2001

Technique for narrow-band imaging in the far ultraviolet based on aberration-corrected holographic gratings.

We have developed a new family of imaging spectrometer designs that combine the imaging power of two-element telescopes with the aberration control of first-generation holographic gratings. The resulting optical designs provide high spatial resolution over modest fields of view at selectable wavelengths. These all-reflective designs are particularly suited for narrow-band imaging below 1050 A, the wavelength below which there are no transmitting materials in the UV. We have developed designs to efficiently map the spatial distribution of UV-emitting material. This mapping capability is absent in current and future astronomical instruments but is crucial to the understanding of the nature of a variety of astrophysical phenomena. Although our examples focus on UV wavelengths, the design concept is applicable to any wavelength.

Journal Article↗
PubMed2001

Exacerbation, then clearance, of mutation-proven Darier's disease of the skin after radiotherapy for bronchial carcinoma: a case of radiation-induced epidermal differentiation?

We investigated a radiotherapy-induced flare and subsequent clearance of skin lesions of a patient with the rare, dominantly inherited genodermatosis, Darier's disease (DD). The DD gene, ATP2A2, was recently isolated and shown to be a cation pump responsible for regulating intracellular calcium homeostasis. A severe exacerbation of Darier's skin lesions developed within the radiation field when 40 Gy of palliative thoracic external-beam radiation therapy and concurrent chemotherapy (cisplatin and hydroxyurea) were delivered for non-small cell lung cancer. The DD lesions subsequently completely cleared from irradiated skin, as they did when a subsequent course of radiation alone was given for a loco-regional tumor recurrence. The two radiation therapy-treated areas of skin remained free from lesions of the skin disorder until the patient's death from progressive lung cancer 9 months later. The nucleotide sequence of the patient's ATP2A2 gene was determined by PCR-based cycle sequencing. We identified four nucleotide sequence variants in the ATP2A2 gene in this patient. Three were probable polymorphisms and the other appeared to be a novel disease-causing mutation (R751Q), situated in the transmembrane portion of the ATP2A2 protein. This finding confirmed the clinical diagnosis. Since epidermis turns over every 3-4 weeks, total and persistent clearance of the DD lesions by chemoradiotherapy suggests that this treatment induced sustained differentiation of the DD-affected skin by an unknown mechanism. Oncologists treating malignant disease in patients with DD should anticipate temporary deterioration in DD-involved irradiated skin. Radiation therapy has therapeutic potential in severe DD.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1998

Method and computer program for controlling the family-wise alpha rate in gene association studies involving multiple phenotypes.

Multiple significance testing involving multiple phenotypes is not uncommon in the context of gene association studies but has remained largely unaddressed. If no adjustment is made for the multiple tests conducted, the type I error probability will exceed the nominal (per test) alpha level. Nevertheless, many investigators do not implement such adjustments. This may, in part, be because most available methods for adjusting the alpha rate either: 1) do not take the correlation structure among the variables into account and, therefore, tend to be overly stringent; or 2) do not allow statements to be made about specific variables but only about multivariate composites of variables. In this paper we develop a simulation-based method and computer program that holds the actual alpha rate to the nominal alpha rate but takes the correlation structure into account. We show that this method is more powerful than several common alternative approaches and that this power advantage increases as the number of variables and their intercorrelations increase. The method appears robust to marked non-normality and variance heterogeneity even with unequal numbers of subjects in each group. The fact that gene association studies with biallelic loci will have (at most) three groups (i.e., AA, Aa, aa) implies by the closure principle that, after detection of a significant result for a specific variable, pairwise comparisons for that variable can be conducted without further adjustment of the alpha level.

Analysis of Variance↗
PubMed1996

Outpatient reduction mammaplasty: a review of 338 consecutive cases.

Reduction mammaplasty is usually accomplished under general anesthesia, often with an overnight stay. With cost-containment pressures, the ability to perform this surgery in an outpatient setting would have obvious benefits. We present a series of 338 patients who have undergone bilateral reduction mammaplasty over a 3-year period. Two hundred eighty-six cases (84.6%) were performed on an outpatient basis and 52 (15.4%) were inpatients. Patient age ranged from 13 to 82 years. Significant differences were found between the two groups regarding average age (34.3 and 42.4 years, respectively) and average total resection weights (1,486.1 gm and 1,895.6 gm, respectively). The maximum total resection weight was 6,000 gm in the outpatient group and 7,140 gm in the inpatient group. Surgical techniques included inferior pedicle (N = 273), central mound (N = 54), and free nipple graft (N = 11). There were no substantial differences in the incidence of minor complications, including wound separation, seromas, hypertrophic scars, infection, and hypopigmentation. Autologous transfusion was utilized in 18 patients early in the series. Of the 175 patients (52%) who returned a follow-up questionnaire, all considered their outpatient experience a positive one. In addition, 33% of the inpatients who responded (N = 8/24) felt their hospital stay was unnecessary. Outpatient surgery resulted in a savings of $1,500 to $2,500 when compared to an overnight stay. Reduction mammaplasty can be performed safely in an outpatient setting and is not necessarily limited by age or extent of resection.

Adolescent↗
PubMed1995

Xylazine.

Explore the source record for details and available documents.

Letter↗
PubMed1992

Pharmacokinetics of pirmenol in young and elderly subjects.

The steady state pharmacokinetics of pirmenol was compared in twelve healthy young (aged 18 to 45 y) and 11 elderly subjects (over 65 y) subjects given pirmenol HCl 100 mg every 12 h for a total of 14 doses. In addition, the single-dose pharmacokinetics of pirmenol was determined following a 100 mg oral dose in the young subject group for comparison with the results of repeated administration. In the young subjects, the mean single-dose and steady-state CLR of pirmenol were similar; however, Ae was 29% higher and CL/f was 22% lower at steady state than after the single dose. Steady-state (fourteenth dose) Cmin, Cmax, tmax, lambda z, Ae, CL/f, CLR and V values were similar in the young and elderly subjects. Based on pharmacokinetic considerations, the dosage of pirmenol is unlikely to differ in young and elderly subjects.

Adult↗
PubMed1991

Review of neonatal screening programme for phenylketonuria.

OBJECTIVE: To review the neonatal screening programme during 1984-8. DESIGN: Analysis of data from screening laboratories and paediatricians. SUBJECTS: All live births in United Kingdom. MAIN OUTCOME MEASURES: Structure of programme; number of infants tested and number with phenylketonuria; number of infants missed; ages at testing and treatment. RESULTS: The proportion of infants tested approached 100%. The incidence of phenylketonuria was 11.7/100,000 births (445 subjects): 273 had classic phenylketonuria and three had defects of cofactor metabolism. One child with phenylketonuria was known to have been missed compared with three in 1979-83 and six in 1974-8. Seven subjects had been missed over the 15 years due to negative test results. All seven had been tested with the bacterial inhibition assay, although only 53% of infants had been so tested; the difference between the expected and observed proportion was significant (Fisher's exact test, p = 0.017). Eleven infants with classic phenylketonuria were not tested by 14 days of age and 23 (8%) did not start treatment until after 20 days, an improvement compared with 36 (15%) in 1979-83. There were, however, wide regional variations (0% to 27% treated after 20 days). CONCLUSION: The screening programme achieves high coverage and effectiveness, although some children are still missed. A national practice for screening may help reduce regional variations.

Age Factors↗
PubMed1991

Management of oil of citronella poisoning.

The management for ingestion of oil of citronella, an essential oil, has traditionally been rigorous, including dilution with milk or oil, and gastric lavage or emesis, taking care to prevent aspiration. Recently our Centre handled five oil of citronella poisonings and their outcomes led us to review our management protocol which had been based on information from standard poisoning texts. The source data used to determine the human toxicity of oil of citronella and the appropriate management of poisoning included a case report of a fatal ingestion of oil of citronella in a child. On scrutiny, however, the management of this poisoning included now out-moded techniques, giving rise to uncertainties in establishing the true cause of the child's death. Our own experiences indicate that advice given in standard texts based on poisoning cases managed with out-moded techniques should be carefully evaluated.

Acyclic Monoterpenes↗