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Biomedical subjects

D M Brooks

Publications and source records attributed to D M Brooks.

30 records · Page 2Linked to original sources
PubMed1993

Mouse strain variability in the expression of the hematopoietic stem cell antigen Ly-6A/E by bone marrow cells.

The cell surface molecule Ly-6A/E provides a convenient marker for primitive stem cells in the hematopoietic tissues of both fetal and adult mice. However, previous studies have shown that Ly-6A/E expression by lymphocytes is variable depending on the haplotype of the Ly-6 locus. Therefore, strain-specific variation in Ly-6A/E expression by bone marrow (BM) cells was investigated. The results show that Ly-6a mice have, on average, 50% of the number of BM cells expressing Ly-6A/E relative to that for Ly-6b mice. Furthermore, among the 5% of BM cells that do not express antigens characteristic of mature T, B, myeloid, or erythroid lineages, which include the primitive hematopoietic stem cell compartment, Ly-6a mice have, on average, more than fivefold fewer Ly-6A/E+ cells relative to that for Ly-6b mice. Isolation of Ly-6A/E- and Ly-6A/E+ cells from mice of both haplotypes showed that, whereas 99% of the marrow repopulating activity (MRA) of C57BL/Ka (Ly-6b) mice could be recovered in the Ly-6A/E+ fraction, only about 25% of the MRA of BALB/c (Ly-6a) was recoverable in the same population. On a per-cell basis, the Ly-6A/E+ cells that were isolated from BALB/c mice were essentially equivalent in MRA to those isolated from C57BL/Ka mice. Thus, whereas a large percentage of the hematopoietic stem cells of Ly-6a mice do not express the Ly-6A/E molecule, the antigen may be used to isolate a subset of stem cells from these mice. These results show that hematopoietic stem cell phenotype can vary between mouse strains and imply that caution should be exercised in the identification of human stem cell antigens such as CD34, because a similar variability may occur between individual humans. To further explore the influence of Ly-6 haplotype on Ly-6A/E expression by specific cell subsets, lymph-node lymphocytes from a panel of mouse strains were analyzed by multiparameter flow cytometry for correlated expression of Ly-6A/E, CD4, and CD8. All Ly-6a strains examined had less than 20% Ly-6A/E+ cells, and those cells were predominantly CD8+ T lymphocytes. In contrast, the Ly-6b strains had greater than 30% Ly-6A/E+ cells, and those cells included CD4+, CD8+, and B lymphocytes.

Animals↗
PubMed1992

Phenotypic analysis of mouse hematopoietic stem cells shows a Thy-1-negative subset.

Mouse hematopoietic stem cells can be identified and enriched from populations of normal bone marrow cells by immunofluorescent labeling of cell surface molecules followed by flow cytometric separation. We show here that the majority of hematopoietic stem cell activity, as defined by long-term competitive repopulation of irradiated animals and by a secondary transplant assay for spleen colony-forming units (CFU-S), could be localized in Ly-6b haplotype mice to a fraction of bone marrow cells that expresses the Ly-6A/E (Sca-1) molecule. Further, an analysis of hematopoietic stem cell activity in bone marrow of mouse strains expressing the Thy-1.1 allele indicated that the vast majority of activity was included in the Thy-1low population. In contrast, hematopoietic stem cell activity found in the bone marrow of Thy-1.2 genotype mouse strains was recovered in both the Thy-1neg and the Thy-1low populations. However, similar to Thy-1.1 strains, most activity was localized to the Ly-6A/E+ population of cells. The difference in Thy-1 phenotype of hematopoietic stem cell activity apparent between Thy-1.1- and Thy-1.2-expressing mouse strains was not caused by differences in the staining intensity of monoclonal antibodies (MoAbs) specific for the Thy-1 alleles. Furthermore, an antiframework MoAb that stains both alleles of Thy-1 separated hematopoietic stem cell activity from mice expressing the two alleles in the same manner as did allele-specific MoAb. The results of this study show that Thy-1 expression is not an invariant characteristic of mouse hematopoietic stem cells, and that mice expressing the Thy-1.1 allele are unique in that hematopoietic stem cell activity is found exclusively in the Thy-1low population.

Animals↗
PubMed1991

Prediction tree for severely head-injured patients.

Prediction tree techniques are employed in the analysis of data from 555 patients admitted to the Medical College of Virginia hospitals with severe head injuries. Twenty-three prognostic indicators are examined to predict the distribution of 12-month outcomes among the five Glasgow Outcome Scale categories. A tree diagram, illustrating the prognostic pattern, provides critical threshold levels that split the patients into subgroups with varying degrees of risk. It is a visually useful way to look at the prognosis of head-injured patients. In previous analyses addressing this prediction problem, the same set of prognostic factors (age, motor score, and pupillary response) was used for all patients. These approaches might be considered inflexible because more informative prediction may be achieved by somewhat different combinations of factors for different patients. Tree analysis reveals that the pattern of important prognostic factors differs among various patient subgroups, although the three previously mentioned factors are still of primary importance. For example, it is noted that information concerning intracerebral lesions is useful in predicting outcome for certain patients. The overall predictive accuracy of the tree technique for these data is 77.7%, which is somewhat higher than that obtained via standard prediction methods. The predictive accuracy is highest among patients who have a good recovery or die; it is lower for patients having intermediate outcomes.

Adult↗
PubMed1985

A survey of clinical training in music therapy: degree of compliance with NAMT guidelines.

This study compared the experiences and responsibilities of music therapy interns with requirements outlined in the Guidelines for Establishing and Maintaining Music Therapy Clinical Training Programs (National Association for Music Therapy, Inc., 1983). Subjects were 134 music therapy clinical training directors and 75 music therapy interns. Results from the intern survey indicated that over 80% of the interns were more than satisfied with their clinical training experiences. However, the data revealed several areas of concern. First, 75% of the directors and 92% of the responding interns were female; this response suggests that music therapy is not recognized as a viable career choice among male music majors. In addition, 22% of the responding clinical training facilities were not affiliated with the closest NAMT-approved college or university; reported range between these facilities and the nearest university was 5 to 1,500 miles, with a mean of 392 miles. The authors concluded that the affiliate process is often meaningless. While the Guidelines require training in "Administrative skills, i.e., budgeting, program proposals, organizational structures," nearly 63% of intern respondents had not received such training. The authors recommend that the Guidelines be rewritten and professionally printed, that interns and clinical training directors be required to complete annual questionnaires, and that the affiliation between clinical training facility and academic institution be strengthened.

Data Collection↗
PubMed1983

Development and implementation of a music/activity therapy intake assessment for psychiatric patients. Part I: initial standardization procedures on data from university students.

The stimulus for the Music/Activity Therapy Intake Assessment was a recent publication by the Joint Commission on Accreditation of Hospitals requiring for activity services, "assessment of the patient's needs, interests, life experiences, capacities, and deficiencies" (1981, p. 126). The Assessment was written in the spring of 1982 and contains four sections: Activity Preference, Organizational involvement, Attitude Survey, and Post-Interview Observations. The purpose of the present study was to investigate the psychometric properties of the Attitude Survey. The Attitude Survey was administered to 214 university students enrolled in three areas of study: human science, performance, and liberal arts. Results show that each of the three scales in the Survey is internally consistent (.63 to .74), that each scale measures a single large dimension, and that two of the three scales significantly discriminate between groups of students (p less than .05). The authors conclude that the Attitude Survey possesses adequate psychometric properties to justify its continued use as part of the Music/Activity Intake Assessment.

Attitude to Health↗
PubMed1982

Clinical trial of propranolol in post-traumatic neuralgia.

In view of several case reports of relief of various neuralgias by propranolo, a double-blind cross-over trial using this drug was conducted in 10 patients with severe persistent pain and paraesthesiae following upper limb peripheral nerve injuries. The patients received up to 240 mg of propranolol per day. Only one patient reported pain relief, but this patient withdrew from the trial. An open trial of propranolol was conducted in 6 other patients with a variety of peripheral nerve lesions. Of these, neuroma tenderness was transiently reduced in one patient and the hyperaesthesia of a painful scar was relieved in another. Routine use of propranolol in such patients cannot be recommended.

Adult↗
PubMed1980

Frustration as a factor in the height of low achievers' self-portraits.

It was hypothesized that the large variance in low achievers' self-portraits may be related to frustration and symbolic acting out. 29 low achievers in Reading and Mathematics were given the Describe Your School inventory. Subjects below the median drew pictures which were taller than pictures drawn by subjects above the median score. It was concluded that frustation must be considered when using height of drawing to analyze low achievers' self-portraits.

Acting Out↗
PubMed1978

Long-term results of ulnar to median nerve pedicle grafts.

Nerve pedicle grafts in the upper limb were performed on nine patients with Volkmann's Ischaemia. Long-term follow-up of three cases has shown that the results of this operation are successful. Sensory and motor recovery of the median nerve occurs and consequently useful hand function is regained. Since Volkmann's Ischaemic contracture is not rare in developing countries, this operation should be the treatment of choice when the median and ulnar nerves have been damaged beyond hope of recovery.

Adult↗
PubMedDate not supplied

Evolution of the multidomain protein wheat germ agglutinin.

We compared the homologous amino acid sequences of hevein and each of the four domains (A, B, C, and D) of wheat germ agglutinin and used them to construct a pseudophylogenetic tree relating these sequences to a hypothetical common ancestor sequence. In the crystal structure of the wheat germ agglutinin dimer, six pseudo-two-fold rotational symmetry axes have previously been located in addition to the true twofold axis. Four of these relate two nonidentical domains to each other in each of the four possible pairs constituting the sugar-binding sites (A1D2, A2D1, B1C2, and B2C1). The remaining two relate contiguous unique pairs of sugar-binding sites to each other (A1D2 to B1C2, and A2D1 to B2C1). These latter two sets of pairs are related to each other by the true twofold axis. Side chains that mediate sugar binding in the interfaces of each of the four pairs were found to be largely conserved. The sequence homology, taken together with these pseudo-symmetry elements in the dimer structure, suggests a pathway for the evolution of the four-domain molecule from a single-domain dimer that can be correlated with simultaneous development of the saccharide-binding sites.

Amino Acid Sequence↗
PubMedDate not supplied

Electric power induction through an isolated intestinal pouch.

A new transintegumental power transformer uses the walls of an isolated intestinal pouch to separate primary and secondary coils. It may surpass transcutaneous devices in heat dissipation potential and in comfort. It was acutely tested in 13 dogs. Corrections in geometry and insulation were suggested by the nine initial trials. In the remaining four animals, up to 14.1 W were delivered, incrementing over 90 to 395 min. Three pouch and two remote thermistors recorded temperature (T) at 10 min intervals. Thirty sets of data were taken at 4 W or less (Group A), 31 at 4-8 W (Group B), and 16 at more than 8 W (Group C). T elevations above reference drift were 0.096 + 0.062 degrees C, 0.468 + 0.234 degrees C, and 0.876 + 0.156 degrees C for groups A, B, and C, respectively. These were significant by t-tests (p less than 0.001 for Group A vs. B; p less than 0.05 for Group B vs. C). The concept appears to be feasible, and longer term implantation trials seem justified.

Animals↗