Biomedical subjects

T Donahue

Publications and source records attributed to T Donahue.

8 recordsLinked to original sources

PubMed2001

The determination of 11-nor-delta9-tetrahydrocannabinol-9-carboxylic acid (THC-COOH) in hair using negative ion gas chromatography-mass spectrometry and high-volume injection.

The determination of 11-nor-delta9-THC-9-carboxylic acid (THC-COOH) in hair specimens at the sensitivity required to detect marijuana users is a difficult analytical problem. A sensitive and specific method has been developed for the quantitative assay of THC-COOH in hair. Hair specimens were washed, incubated in sodium hydroxide, subjected to solid-phase extraction, and analyzed using high-volume injection coupled with negative chemical ionization (NCI) mass spectrometry. A common disadvantage of chemical ionization, the production of a single mass-to-charge ratio ion, was also addressed. By specific selection of the derivatizing agent, three ions were monitored, allowing the calculation of two ion ratios, as in electron impact mode. The method was applied to several hair specimens taken from known marijuana users and workplace specimens. This is the first publication describing the use of high-volume injection and NCI mass spectrometry for the determination of THC-COOH in hair.

Adult↗

PubMed2000

CD8 expression on B cells in chronic lymphocytic leukemia: a case report and review of the literature.

The expression of CD8, a restricted T-cell antigen, on B cells in B chronic lymphocytic leukemia is rare, and its significance, if any, remains unknown. We report herein a patient with B chronic lymphocytic leukemia in whom CD8 was strongly expressed on all B cells, both in the bone marrow and peripheral blood. The patient required no therapy for 6 years after being diagnosed as having B chronic lymphocytic leukemia. Then, when the disease progressed, he was treated with conventional doses of fludarabine phosphate (25 mg/m(2) daily for 5 days), but unlike other patients with B chronic lymphocytic leukemia he tolerated this therapy poorly. He received a total of only 4 series of fludarabine therapy, and following each course of treatment, he developed considerable myelosuppression. After the fourth course of therapy, his bone marrow failed to show any evidence of regeneration, and he died as a result of intercurrent respiratory tract infection 1 month after his last dose of fludarabine was given.

Antigens, CD19↗

PubMed1999

A low-temperature origin for the planetesimals that formed Jupiter.

The four giant planets in the Solar System have abundances of 'metals' (elements heavier than helium), relative to hydrogen, that are much higher than observed in the Sun. In order to explain this, all models for the formation of these planets rely on an influx of solid planetesimals. It is generally assumed that these planetesimals were similar, if not identical, to the comets from the Oort cloud that we see today. Comets that formed in the region of the giant planets should not have contained much neon, argon and nitrogen, because the temperatures were too high for these volatile gases to be trapped effectively in ice. This means that the abundances of those elements on the giant planets should be approximately solar. Here we show that argon, krypton and xenon in Jupiter's atmosphere are enriched to the same extent as the other heavy elements, which suggests that the planetesimals carrying these elements must have formed at temperatures lower than predicted by present models of giant-planet formation.

Cold Temperature↗

PubMed1998

L1 antibodies block lymph node fibroblastic reticular matrix remodeling in vivo.

L1 is an immunoglobulin superfamily adhesion molecule highly expressed on neurons and involved in cell motility, neurite outgrowth, axon fasciculation, myelination, and synaptic plasticity. L1 is also expressed by nonneural cells, but its function outside of the nervous system has not been studied extensively. We find that administration of an L1 monoclonal antibody in vivo disrupts the normal remodeling of lymph node reticular matrix during an immune response. Ultrastructural examination reveals that reticular fibroblasts in mice treated with L1 monoclonal antibodies fail to spread and envelop collagen fibers with their cellular processes. The induced defect in the remodeling of the fibroblastic reticular system results in the loss of normal nodal architecture, collapsed cortical sinusoids, and macrophage accumulation in malformed sinuses. Surprisingly, such profound architectural abnormalities have no detectable effects on the primary immune response to protein antigens.

Animals↗

PubMed1998

A comparative analysis of surveyors from six hospital accreditation programmes and a consideration of the related management issues.

PURPOSE: To gather data on how accreditors manage surveyors, to compare these data and to offer them to the accreditors for improvement and to the scientific community for knowledge of the accreditation process and reinforcement of the credibility of these processes. DATA SOURCE: The data were gathered with the aid of a questionnaire sent to all accreditors participating in the study. RESULTS: An important finding in this comparative study is the different contractual relationships that exist between the accreditors and their surveyors. CONCLUSION: Surveyors around the world share many common features in terms of careers, training, work history and expectations. These similarities probably arise from the objectives of the accreditors who try to provide a developmental process to their clients rather than an 'inspection'.

Accreditation↗

PubMed1996

Accreditation programs for hospitals: funding and operation.

Accreditation is a formal process by which an authorized body assesses and recognizes an individual, an organization (like a hospital), a program, or a group as complying with requirements such as standards or criteria. This article analyses and compares the activity and funding of six health care accrediting bodies which operate in five different countries, and which in 1994, accredited over 5000 health centres. The data included in this article could be useful for other institutions who wish to commence accreditation programmes for health care organizations.

Accreditation↗

PubMed1989

Pharmacist-based i.v. theophylline therapy.

With the support and guidance of the medical staff, a protocol for IV theophylline dosing and monitoring has been implemented. The patients' theophylline needs are individually determined by pharmacists using clinical criteria and historical data determined for each patient. Ongoing monitoring and dosage adjustments are provided. The protocol is described where a therapeutic range of 10-20 mcg/mL was maintained 84% of the time as verified by quality assurance audits.

Adolescent↗

PubMedDate not supplied

Left ventricle-to-ascending aorta communication complicating composite graft repair undetected by aortography: diagnosis by transesophageal echocardiography.

A 57-year-old man underwent composite ascending aortic conduit and prosthetic aortic valve repair of a sinus of Valsalva aneurysm. The patient's course was complicated by recurrent aneurysm formation caused by a communication between the left ventricular outflow tract and the ascending aorta outside the conduit. Transesophageal echocardiography documented the anatomic and functional characteristics of this complication, whereas aortography failed to demonstrate them. Findings at surgery confirmed the transesophageal echocardiogram results of a left ventricular outflow tract to aorta communication, a normal prosthetic aortic valve, and an intact distal anastomosis of the conduit with the aorta. Transesophageal echocardiography is a useful modality for the evaluation of composite graft repairs of the aortic valve and ascending aorta.

Aorta↗