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Biomedical subjects

M McGinnis

Publications and source records attributed to M McGinnis.

10 recordsLinked to original sources
PubMed2001

Effect of beta radiation on the crystallization of sodium chlorate from water: a new type of asymmetric synthesis.

Sodium chlorate is an achiral molecule that crystallizes from water in the chiral space group P2(1)3. In the absence of chiral perturbations, a random distribution of (+) and (-) crystals is obtained. Kondepudi(2) has shown that constantly stirring an evaporating NaClO(3) solution gives mostly either (+) or (-) crystals. Repeating this experiment many times gives equal numbers of (+) and (-) sets of crystals. Herein we report that when evaporating aqueous NaClO(3) is subjected to beta particles from an Sr-90 source, an asymmetric distribution of (+) and (-) crystals favoring the (+) crystals is obtained. The beta particles are energetic polarized electrons that are approximately 80% of left-handed helicity. By a poorly understood mechanism, the spin polarized electrons produce chiral nucleating sites that favor formation of the (+)-NaClO(3) crystals. Exposure of the evaporating solution instead to energetic positrons from an Na-22 source yields mainly (-)-NaClO(3) crystals. Polarized positrons are of predominantly right-handed helicity. One may conclude that the chirality of the radiation is correlated with the chirality of the crystals being generated.

Journal Article↗
PubMed2000

Auditory cortex accesses phonological categories: an MEG mismatch study.

The studies presented here use an adapted oddball paradigm to show evidence that representations of discrete phonological categories are available to the human auditory cortex. Brain activity was recorded using a 37-channel biomagnetometer while eight subjects listened passively to synthetic speech sounds. In the phonological condition, which contrasted stimuli from an acoustic /dae/-/tae/ continuum, a magnetic mismatch field (MMF) was elicited in a sequence of stimuli in which phonological categories occurred in a many-to-one ratio, but no acoustic many-to-one ratio was present. In order to isolate the contribution of phonological categories to the MMF responses, the acoustic parameter of voice onset time, which distinguished standard and deviant stimuli, was also varied within the standard and deviant categories. No MMF was elicited in the acoustic condition, in which the acoustic distribution of stimuli was identical to the first experiment, but the many-to-one distribution of phonological categories was removed. The design of these studies makes it possible to demonstrate the all-or-nothing property of phonological category membership. This approach contrasts with a number of previous studies of phonetic perception using the mismatch paradigm, which have demonstrated the graded property of enhanced acoustic discrimination at or near phonetic category boundaries.

Acoustic Stimulation↗
PubMed2000

Urban issues in health promotion strategies.

The powerful influence of behavioral choices on health status is well established. The implications and challenges for urban populations are formidable. Understanding urban environments will better prepare health promotion professionals to deal effectively with the forces affecting health-related behaviors. In thinking about urban health promotion in the United States, researchers often distinguish between 2 frameworks; one contending with urbanization, which affects most of us, and another contending with inner-city environments, where many of the deepest needs are. Urbanization confers both benefits and liabilities, but the single greatest challenge for health promotion may lie in reestablishing positive social connections. In contrast, 2 key features of the inner-city environment may be the negative ecological forces within neighborhoods and the lack of control over one's fate. Too often, prescriptions for the inner city stereotype its problems and ignore its strengths. For the inner city, important foundation stones for the future include ways to build on these strengths through positive connections and increased community control through coalition building.

Health Promotion↗
PubMed1997

Mismatches for two major and one minor histocompatibility antigen correlate with a patient's rejection of a bone marrow graft from a serologically HLA-identical sibling.

We describe the case of a patient with chronic myeloid leukemia who rejected a bone marrow (BM) graft from a sibling donor believed to be HLA identical. Sequencing of the HLA genes showed the mother to be heterozygous for two closely related HLA haplotypes that could not be resolved by serological typing. The donor and the recipient had each inherited a different maternal haplotype resulting in allelic mismatches for the HLA-B35 and the HLA-DR11 genes. T cell cytotoxicity directed towards the donor's B35 allele was detected in the patient, in addition to CTL specificity for an HLA-B7-restricted minor histocompatibility antigen carried by the donor, resulting in three histocompatibility mismatches between the BM donor and the recipient.

Adult↗
PubMed1993

Congenital peribronchial myofibroblastic tumor (so-called "congenital leiomyosarcoma"). A distinct neonatal lung lesion associated with nonimmune hydrops fetalis.

An unusual solid tumor composed of myofibroblasts in an infant with nonimmune hydrops fetalis is presented together with a review of previous cases reported under a variety of different names, most notably congenital leiomyosarcoma. Immunocytochemical, ultrastructural, and flow cytometric data plus an analysis of fetal lung specimens from various times during lung development suggest that this tumor arises from the condensed mesenchyme that surrounds those respiratory ducts that go on to form large bronchi. Because of its age of onset, cellular composition, and benign biological behavior we believe that this tumor is analogous to two other congenital myofibroblastic tumors, congenital mesoblastic nephroma, and spindle cell tumor of the intestinal tract. Although the term myofibroblastoma has gained popularity in recent reports describing localized proliferations of myofibroblasts in adults, we would like to emphasize the unique developmental origin of this lesion and suggest the term congenital peribronchial myofibroblastic tumor.

Humans↗
PubMed1989

Fractures of the scapula: a retrospective study of 40 fractured scapulae.

Forty fractured scapulae in 39 patients treated by nonoperative means were retrospectively reviewed. The nature of injury, associated injuries, site of fracture, and results were evaluated. The data obtained in this series were compared to data from previous studies. Various associated injuries were found in these patients with scapula fractures. Many of these injuries were life threatening although some could have been easily overlooked on initial presentation. Adequate followup was achieved in 67% of the patients. Seventy-three per cent of the patients had good to excellent results using the criteria of subjective complaints, strength, and range of motion. Three of the 39 patients had poor results. These were multiply injured patients or elderly patients in whom early range of motion was not done.

Adolescent↗
PubMedDate not supplied

Gardening as therapy for children with behavioral disorders.

A gardening program was implemented by the nursing staff for in-patients on a children's psychiatric unit. By establishing and maintaining the garden and participating in garden group discussions, patients practiced teamwork, coped with delays in gratification, studied life cycles and discussed topics of therapeutic significance. The success of this program provides anecdotal evidence for the efficacy of gardening as a supplemental therapy for children with behavioral disorders.

Child↗
PubMedDate not supplied

Comparison of resorbable and nonresorbable guided bone regeneration materials: a preliminary study.

The purpose of this study was to compare bone regeneration within a surgically created defect using three different resorbable membranes (polyglactin 910 knitted mesh/Vicryl, freeze-dried fascia lata, and crosslinked bovine type I collagen/BioMend) and two nonresorbable membranes (expanded polytetrafluoroethylene/Gore Tex, and polytetrafluoroethylene/Millipore). Each of three adult male dogs underwent surgical preparation of six bicortical defects of the calvarium, each 1.5 cm in diameter. The experimental barrier membranes were placed on both sides of the defects (inner and outer cranial tables). Five of the six defects were covered randomly by one of the five membrane materials, and one was left uncovered to serve as a negative control. The animals were sacrificed 10 weeks after membrane placement. Bone response was measured clinically, as well as radiographically, via densitometric examination. All surgical sites healed uneventfully. Variable degrees of new bone growth were present at all sites when evaluated by both clinical and radiographic examination. The general trend of observed osseous response indicates a greater, although not statistically significant, degree of bone growth using nonresorbable membranes. The animal model employed appears to be an efficient and reliable means of evaluating guided bone regeneration membranes.

Animals↗