Biomedical subjects

W C Young

Publications and source records attributed to W C Young.

At least 19 recordsLinked to original sources

PubMed2000

The formation of reactive oxygen species catalyzed by neutral, aqueous extracts of NIST ambient particulate matter and diesel engine particles.

It is important to characterize the chemical properties of particulate matter in order to understand how low doses, inhaled by a susceptible population, might cause human health effects. The formation of reactive oxygen species catalyzed by neutral, aqueous extracts of two ambient particulate samples, National Institute of Standards & Technology (NIST) Standard Reference Materials (SRM) 1648 and 1649, and two diesel particulate samples, NIST SRM 1650 and SRM 2975, were measured. The formation of reactive oxygen species was estimated by measuring the formation of malondialdehyde from 2-deoxyribose in the presence of ascorbic acid; H2O2 was not added to this assay. SRM 1649, ambient particulate matter collected from Washington, DC, generated the most malondialdehyde, while SRM 2975, diesel particulate matter collected from a forklift, yielded the least amount. Desferrioxamine inhibited the formation of malondialdehyde from the particulate samples providing additional data to support the observation that transition metals were involved in the generation of reactive oxygen species. Six transition metal sulfates (iron sulfate, copper sulfate, vanadyl sulfate, cobalt sulfate, nickel sulfate, and zinc sulfate) were assayed for their ability to generate reactive oxygen species under the same conditions used for the particulate samples in order to facilitate comparisons between particles and these transition metals. The concentration of transition metals was measured in aqueous extracts of these particulate samples using ion-coupled plasma mass spectrometry (ICP-MS) analysis. There was qualitative agreement between the concentrations of Fe, Cu, and V and the amount of malondialdehyde produced from extracts of these particulate samples. These data suggest that transition metals can be dissolved from particles in neutral, aqueous solutions and that these metals are capable of catalyzing the formation of reactive oxygen species.

Air Pollutants, Occupational↗

PubMed1995

Eye movement desensitization/reprocessing: its use in resolving the trauma caused by the loss of a war buddy.

EMDR resulted in the rapid relief of symptoms of posttraumatic stress disorder in refractory traumatic imagery in a Vietnam veteran. The results were maintained at nine-month follow-up. EMDR appears to be a viable technique in anecdotal reports but the limitations of a single-case study and the lack of adequate large controlled studies prevent generalization beyond a case-by-case assessment. Despite controversial reports, it appears that more rigorous evaluation of EMDR needs to be done to document the factors that operate in the use of EMDR.

Combat Disorders↗

PubMed1993

Sadistic ritual abuse. An overview in detection and management.

Sadistic ritual abuse, including satanic cult abuse, is emerging as a syndrome among people with severe dissociative disorders, including multiple personality disorder. This article discusses the essential features that compose the clinical picture of sadistic ritual abuse in adults, adolescents, and children. Particular attention is paid to the differences between adolescents who may have been victimized by adults in sadistic and ritualized ways and disenfranchised "teenage dabblers" who may temporarily adopt a ritualized lifestyle as a way of expressing or acting out. The article also covers guidelines for appropriate medical, pharmacologic, and referral interventions. The controversy surrounding sadistic ritual abuse is discussed thoroughly, and primary care physicians are advised of the current status of understanding and validation in this area.

Adolescent↗

PubMed1992

Solvent extraction efficiencies of mutagenic components from diesel particles.

In order to determine the efficiency of organic solvent extractions of fresh diesel-engine exhaust particles a series of Soxhlet extractions were set up using single and sequential extractions of fresh diesel particles with solvents of increasing polarities. Single extractions were carried out with methylene chloride, methanol, acetone and acetonitrile. A single filter was sequentially extracted with methylene chloride followed by methanol, acetone and acetonitrile. Methylene chloride extracted the most mutagenicity relative to the other three solvents. In addition, methylene chloride extracted 97% of the total extracted mutagenicity from a sequential series of extractions. Therefore, we conclude that of the solvents tested methylene chloride extracts the highest proportion of mutagens from fresh diesel exhaust and little mutagenicity is lost using methylene chloride as the only extraction solvent.

Acetone↗

PubMed1992

Absence of the carotid canals at skull base CT.

Congenital absence of one or both internal carotid arteries (ICAs) has a high association with circle of Willis aneurysm formation. Since the carotid canals in the skull base form secondary to the presence of the embryonic ICA, absence or hypoplasia of a carotid canal on a computed tomographic (CT) scan through the skull base should suggest a congenital ICA abnormality and prompt a search for associated intracranial vascular abnormalities. Of four patients with carotid canal underdevelopment evident at CT, two had associated circle of Willis aneurysms and a third had an extensive skull base rete mirabile supplying an abnormal tangle of vessels in the basal cisterns. Only two patients (one with an aneurysm, one with the skull base rete mirabile) presented with subarachnoid hemorrhage. One patient presented with monocular decreasing vision due to an enlarging aneurysm, and one patient was essentially asymptomatic. If asymmetry or absence of the carotid canals is evident on CT scans of the head, further evaluation to rule out a potentially life-threatening intracranial vascular abnormality such as those found in these patients should be seriously considered, even in a young or asymptomatic patient.

Aged↗

PubMed1992

Radiation-induced optic neuropathy: correlation of MR imaging and radiation dosimetry.

The authors performed topographic correlation of dosimetric measurements with contrast medium-enhanced magnetic resonance (MR) imaging signal aberration in two cases of radiation optic neuropathy. The region of pathologic contrast enhancement in the optic nerve and chiasm had received 55-62 Gy, which supports the theory that the risk of injury to the optic nerve and chiasm increases steeply with radiation doses above the tolerance level of 50-55 Gy.

Female↗

PubMed1991

Ames assay mutagenicity and electronic structure calculations of bromomethylfluoranthenes, chloromethylfluoranthenes, and hydroxymethylfluoranthenes.

The mutagenicities of the five possible isomers of bromomethylfluoranthene, chloromethylfluoranthene, and hydroxymethylfluoranthene were determined in the Ames assay using strains TA100 and TA98 without the addition of rat-liver S9 tissue extract. The mutagenicities of the bromomethyl and chloromethylfluoranthenes ranged from 25 to 6000 rev./nmol. The most mutagenic compound was 8-chloromethylfluoranthene in strain TA98 (6000 rev./nmol). The reactivities of the bromomethylfluoranthenes and the chloromethylfluoranthenes were estimated from electronic structure calculations using the MNDO and the PM3 semi-empirical methods. The bromomethylfluoranthenes showed the smallest differences between the heats of formation of the carbocations and the heats of formation of the parent bromomethyl derivatives. Therefore, the bromomethylfluoranthenes were estimated to be the most reactive of the halomethylfluoranthenes studied. The compound that showed the largest change in heat of formation (the most stable halomethylfluoranthene) going from the halomethylfluoranthene to the carbocation was 2-chloromethylfluoranthene. However, neither the most reactive nor the most stable halomethylfluoranthenes were the most mutagenic in either strain of bacteria. These results are interpreted to suggest that the reactivity of the parent halomethylfluoranthene is not a critical factor in the mechanism by which these compounds are mutagenic, but some other factor, perhaps intercalation, must be a critical step in the mechanism of mutagenesis of these compounds.

Acetone↗

PubMed1991

Patients reporting ritual abuse in childhood: a clinical syndrome. Report of 37 cases.

Thirty-seven adult dissociative disorder patients who reported ritual abuse in childhood by satanic cults are described. Patients came from a variety of separate clinical settings and geographical locations and reported a number of similar abuses. The most frequently reported types of ritual abuse are outlined, and a clinical syndrome is presented which includes dissociative states with satanic overtones, severe post-traumatic stress disorder, survivor guilt, bizarre self abuse, unusual fears, sexualization of sadistic impulses, indoctrinated beliefs, and substance abuse. Questions relating to issues of reliability, credibility and verifiability are addressed in depth, and the findings and implications are discussed.

Abreaction↗

PubMed1991