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Biomedical subjects

J D Wilson

Publications and source records attributed to J D Wilson.

At least 505 records · Page 28Linked to original sources
PubMedDate not supplied

Challenges of recording human fetal auditory-evoked response using magnetoencephalography.

OBJECTIVE: Our goals were to successfully perform fetal auditory-evoked responses using the magnetoencephalography technique, understand its problems and limitations, and propose instrument design modifications to improve the signal quality and success rate. METHODS: Fetal auditory-evoked responses were recorded from four fetuses with gestational ages ranging from 33-40+ weeks. The signals were recorded using a gantry-based superconducting quantum interference device. Auditory stimulus was 1 kHz tone burst. The evoked signals were digitized and averaged over an 800 ms window. RESULTS: After several trials of positioning and repositioning the subjects, we were able to record auditory-evoked responses in three out of the four fetuses. Since the superconducting quantum interference device array design was not shaped to fit over the mother's abdomen, we experienced difficulty in positioning the sensors over the fetal head. CONCLUSIONS: Based on this pilot study, we propose instrument design that may improve signal quality and success rate of the fetal magnetic auditory-evoked response.

Equipment Design↗
PubMedDate not supplied

Genetic control of extraglandular aromatase activity in the chicken.

Feminization of feathers in the Sebright cock is the result of increase in the activity of skin aromatase. This increased estrogen synthesis is the consequence of an autosomal dominant mutation that causes an increase in the specific androgen-binding cytochrome P450 oxidase involved in the reaction. Since this oxidase appears to be kinetically indistinguishable from the activity in control ovary we believe that the mutation causes an increased steady-state level of normal enzyme. The mechanism by which the mutation acts is unknown, but its presence implies that in normal birds an allele of the mutation limits the activity of the enzyme in all tissues other than ovary.

Androgens↗
PubMedDate not supplied

MR characteristics of low-flow facial vascular malformations in children and young adults.

The purpose of this report is to describe the magnetic resonance (MR) imaging characteristics of low-flow vascular malformations of the face. We studied six patients ranging in age from 1 month to 20 years old, with surgically proven or clinically certain low-flow vascular malformations of the face. T1-weighted MR images of five lesions showed homogeneous intermediate to low signal intensity, similar to the signal intensity of muscle. T1-weighted images of one lesion showed mild high signal intensity and image of another demonstrated fatty infiltration. After contrast administration, images of four lesions showed moderate to marked enhancement, three diffused and one patchy. On T2-weighted sequences, five lesions were heterogeneously of high signal and one of low signal intensity. Three lesions exhibited low-signal septa, and two revealed low-signal vascular flow voids on both types of sequences. Satellite nodules were present in three instances. Low-flow vascular malformations involving the face in children and young adults have a heterogeneous and nonspecific appearance on MR images. They should be considered in the differential diagnosis of all facial masses presenting in children and young adults. Enhancement with contrast material is essential to localize the mass.

Adolescent↗
PubMedDate not supplied

Cat-scratch disease. Subtle vertebral bone marrow abnormalities demonstrated by MR imaging and radionuclide bone scan.

Cat-scratch disease (CSD) is a benign, self-limited cause of lymphadenitis occurring mainly in children and young adults. Its etiology is a delicate, small gram-negative pleomorphic bacillus. Less common manifestations of CSD are seen in 5% of patients and include Parinaud's oculoglandular syndrome (with enlargement of the preauricular nodes), parotid gland enlargement, encephalitis, radiculopathy, pneumonitis, erythema nodosum, thrombocytopenia, and lytic bone lesions. We describe a patient in whom magnetic resonance imaging initially detected subtle vertebral bone marrow abnormalities that correlated with the site of abnormality on a subsequent radionuclide bone scan.

Adult↗
PubMedDate not supplied

MRI features of intracranial sarcoidosis mimicking meningiomas.

We present three young African-American patients in whom magnetic resonance imaging (MRI) showed dural based masses that were initially thought to represent meningiomas. Two patients underwent surgery and the diagnosis of sarcoidosis was made. The third patient underwent a trial of steroids with considerable improvement of her symptoms. We suggest that sarcoidosis should always be considered in the differential diagnosis of dural-based masses which have MRI characteristics similar to those of meningiomas. The possibility of sarcoidosis should lead to appropriate laboratory tests and therapy.

Adult↗
PubMedDate not supplied

Aerodynamic sizing of tobacco smoke particulate from commercial cigarettes.

Aerodynamic sizing of smoke particulate was performed on a variety of commercial cigarettes using a single particle aerodynamic relaxation time (SPART) analyzer. Cigarettes tested were rated as "medium," "low," or "ultra-low" tar by the Federal Trade Commission method. Aerodynamic size determinations were made with filters attached and with filters removed. Smoke particles from all cigarettes were less than 0.6 micron mass median aerodynamic diameter, and particle size was not affected by filters. Commercial filters reduced particle number concentration by 20-96%. Particle number concentration of smoke particles from some "low" tar cigarettes was found to be similar to some "medium" tar cigarettes. Particle number per puff increased as the cigarette shortened. These findings suggest that estimation of tar delivery to smokers from cigarettes should include puff number information. Also, the ultimate respiratory tract deposition site of smoke particles is not affected by filters since particle size was not altered by passing smoke through cigarette filters.

Filtration↗
PubMedDate not supplied

Inheritance of the henny-feathering trait of the Sebright bantam chicken.

The henny -feathering trait of the Sebright bantam chicken is the result of an enhanced rate of estrogen synthesis (aromatase activity) in skin and other peripheral tissues of this bird. To gain insight into the underlying nature of this mutation, we examined the inheritance of this trait using a sensitive isotopic assay for aromatase activity. All birds of the F1 generation obtained by crossing homozygous henny X non- henny chickens expressed increased aromatase in the skin, and the males exhibited henny -feathering plumage. The average rate of aromatase activity in the skin of F1 chicks was approximately half that of homozygous henny chicks. The distribution of increased aromatase activity in the F2 generation and in the backcrosses of F1 to the two types of parental strains suggest that the enzyme activity in extragonadal tissues is regulated predominantly by one autosomal gene. Attempts to demonstrate linkage to several known loci by backcrossing F1 heterozygotes with parental chickens carrying a variety of genetic markers were unsuccessful. We conclude that the enhanced estrogen synthesis in extragonadal tissues in chickens carrying this gene is inherited as an autosomal codominant but that a half maximal level of the enzyme is sufficient to allow full development of female feathering in affected male birds so that henny -feathering is transmitted as a dominant trait.

Animals↗
PubMedDate not supplied

Inheritance of the henny feathering trait in the golden Campine chicken: evidence for allelism with the gene that causes henny feathering in the Sebright bantam.

The henny feathering mutation causes roosters to develop female feathering morphology as a result of increased conversion of androgen to estrogen (aromatase activity) in extraglandular tissues, including skin. This trait is maintained in two breeds of chickens: the Sebright Bantam and the Golden Campine. To characterize the inheritance of this trait further, we did breeding studies of the Golden Campine and identified the trait by measuring aromatase activity in biopsied skin. As previously established for the Sebright Bantam, the trait is transmitted in the Campine by an autosomal, incomplete dominant mechanism; heterozygous offspring express half the levels of extraglandular aromatase as do homozygous Campines on average. No reversions to wild-type levels were observed in 555 heterozygous offspring of crosses between homozygous Campines and normals. Compound heterozygotes for the trait were obtained by mating homozygous Sebrights and homozygous Campines. When these compound heterozygote birds were crossed to control birds, all 98 offspring had elevated aromatase activity in skin, suggesting that the traits in Sebright and Campine birds are allelic. Furthermore, the restriction fragment length polymorphism pattern performed on genomic DNA was the same in the Sebright and Campine birds. Thus, the phenotypic, endocrine, and genetic features suggest that the traits in Sebright and Campine birds are the same. The trait in the Campine probably was derived from the Sebright.

Alleles↗
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Bread-making as a source of vaginal infection with Saccharomyces cerevisiae. Report of a case in a woman and apparent transmission to her partner.

We report the case of a woman, who baked her own bread, acquiring a vulvovaginal infection caused by saccharomyces cerevisiae, a yeast used extensively in the baking and brewing industries. Her partner was also infected, and the infections proved difficult to eradicate. Oral and topical treatment with nystatin along with disinfection of both patients' underwear produced clinical and microbiologic cure.

Adult↗
PubMedDate not supplied

The Agency for Toxic Substances and Disease Registry's role in development and application of biomarkers in public health practice.

An overview of the Agency for Toxic Substances and Disease Registry's (ATSDR) biomarker program is presented in the context of the paradigm for biomarkers developed by the National Research Council (NRC, 1987, 1991). The status and projected utility of four biomarker studies conducted by NRC and sponsored by ATSDR, the Environmental Protection Agency (EPA), and the National Institute of Environmental Health Sciences (NIEHS) are discussed. These studies include a review of relevant research on biomarkers for specific toxicologic end points, including reproductive toxicology, pulmonary toxicology, neurotoxicology, and immunotoxicology. Also, the scope of related research on exposure characterization being conducted by the ATSDR-sponsored research program at Rutgers University is reviewed. The potential impact of biomarkers on public health assessments and on the range of ATSDR programs is described. Specifically, the role of biomarkers in dose reconstruction, in ATSDR's health studies program, and in the emerging field of molecular epidemiology is reviewed. In addition, future directions and research needs are addressed.

Animals↗
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Differences in the contribution of CD4+ T cells to proislet and islet allograft rejection correlate with constitutive class II MHC alloantigen expression.

Allografts of BALB/c (H-2d) fetal proislets facilitated long-term (> 100 days) reversal of streptozotocin-induced diabetes in CBA/H (H-2k) mice treated with a combination of anti-CD4 and anti CD8 mAbs. Anti-CD8 monotherapy was partially effective in restoring normoglycemia but anti-CD4 mAb treatment of host animals failed to promote allograft function. In contrast, allografts of BALB/c adult islets demonstrated indefinite reversal of diabetes in recipient mice treated only with anti-CD8 mAb. Anti-CD4 monotherapy resulted in only transient restoration of normoglycemia. These findings clearly demonstrate (1) a critical role for CD8 T cells in the acute rejection of pancreatic islet tissue allografts and (2) tissue-specific differences in the participation of CD4 T cells as primary effectors in the rejection reaction. Immunohistochemical studies showed that the capacity for CD4 T cells to initiate the rejection of proislet but not adult islet allografts correlates with the presence/absence, respectively, of graft parenchymal cells that constitutively express Class II MHC alloantigens. Proislet grafts, unlike transplants of purified adult islets, contain heterogeneous tissue components including Class II MHC+ve duct epithelium. Thus, the participation of CD8 and CD4 T cells as primary effectors of graft rejection depends on which class or classes of MHC antigens are constitutively expressed on graft parenchymal cells and are available for recognition. Islet tissue in both rejecting proislet and islet allografts showed de novo induction of Class II MHC alloantigens only after severe disruption to islet architecture had been achieved by infiltrating mononuclear cells. Thus, at this stage of advanced allograft injury, CD4 T cells have the potential to act as secondary effectors, possibly by amplifying the inflammatory reaction and thus accelerating graft destruction. The capacity for antirejection mAb therapy to establish transplant tolerance was facilitated in the islet allograft model where it was necessary to target only the CD8 T cell subpopulation.

Animals↗