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Biomedical subjects

D Andrews

Publications and source records attributed to D Andrews.

At least 55 records · Page 3Linked to original sources
PubMed1998

Comparative assessment of four different Tl-201 tumor uptake indices in the evaluation of brain tumors.

The objective of this study was to determine which semi-quantitative thallium-201 brain tumor index correlated best with clinical outcome. Fifty-two patients had Tl-201 brain single-photon emission computer tomography (SPECT) performed for the evaluation of recurrent brain tumor. A semi-quantitative tumor index was calculated utilizing four currently available techniques: 1) the ratio of average counts of the region of interest (ROI) in the lesion area and its mirror image in normal brain tissue, 2) the ratio of maximum counts of the region of interest in the lesion area and its average counts in the mirror image, 3) the ratio of maximum counts of the region of interest in the lesion area and its mirror image and 4) the ratio of the average counts of the region of interest in the lesion area and the region of interest of the scalp. A two-tailed Student's t test was performed. The mean value plus one standard deviation was used to assess the sensitivity and specificity correlated with clinical follow-up evaluation, defined as inactive or active at the time of brain SPECT by the referring neurosurgeons. Results of correlation coefficient, P value, mean, standard deviation, sensitivity, and specificity of each index using cutoff values were obtained. For those patients with recurrence or residual malignant tumor after therapy, the maximum count ratio index correlated best with clinical outcome. It provided a sensitivity of 92% and specificity of 88% in differentiating active from inactive brain tumors.

Brain Neoplasms↗
PubMed1998

Depletion of anti-Gal(alpha)1-3Gal antibody in baboons by specific alpha-Gal immunoaffinity columns.

Ongoing studies at our center on facilitating transplantation of discordant xenogeneic organs are focused on tolerance induction. To abrogate hyperacute rejection, we have used adsorption methods to eliminate natural anti-Gal(alpha)1-3Gal (alphaGal) antibodies from the circulation of baboons. We have analyzed data concerning antibody removal in baboons that were 1) immunologically naive, 2) receiving conventional pharmacologic immunosuppressive therapy (IS), and 3) treated with a conditioning regimen for tolerance induction. We compared the efficiency of removing alphaGal antibody 1) by perfusion of whole blood through an alphaGal affinity column (CP; n=5) with 2) perfusion of plasma (separated from cellular components by apheresis) through an alphaGal column (CPA; n=39). Our studies demonstrate that 1) CP and CPA are equally effective in removing anti-alphaGal antibody, 2) CPA is the method of choice if multiple adsorptions are required, 3) CPA in naive animals transiently affects levels of total IgG and IgM, 4) four CPAs repeated at 2-4 day intervals in association with heavy IS reduce the pool of anti-alphaGal antibody and total Ig, and 5) splenectomy and/or IS delay the return of anti-alphaGal antibody.

Animals↗
PubMed1997

In vivo accumulation of the same anti-melanoma T cell clone in two different metastatic sites.

In a patient with progressing metastatic melanoma, we showed that the same autologous tumor-cytolytic CD8+ tumor infiltrating lymphocyte (TIL) clone accumulated in two separate metastatic sites. This clone, which represented three of eight independently derived clones from a tumor deposit on the skin of the abdomen, also represented two of eight clones derived from a skin lesion on the shoulder. This clone could be identified by its use of a unique TCRBV2-nD1n-J1S6 sequence, and could also be detected by single-stranded conformational polymorphism (SSCP) as the dominant TCRBV2-expressing clone among CD8+ TILs propagated from both shoulder and abdominal lesions. Using SSCP analysis, we also demonstrated that this clone was dominant in the fresh tumor tissue and in all TILs in which CD8+ were strongly represented, including several separate but parallel cultures. The SSCP pattern for this clone was not apparent among CD4+ TILs or CD8+ peripheral blood mononuclear cells. The SSCP analysis of the tumor tissue prior to in vitro culture is an indication that the selection for this anti-tumor cytotoxic T cell clone was a reflection of its in vivo accumulation. Thus, we provide evidence that melanomas are immunogenic and able to select for cytotoxic antitumor-specific TIL clones that are expanded in vivo and can circulate to accumulate in different tumor sites. However, because these clones were isolated from progressing tumor metastases, the accumulation of these specific cytotoxic T cells was not sufficient to contain tumor growth.

Abdomen↗
PubMed1997

Reading and metaphonological outcomes in late talkers.

Children with a history of slow expressive language development (SELD) were followed to second grade, at which point outcomes in terms of speech, language, cognitive skills, reading achievement, and metaphonological performance were evaluated. Although there were some statistically significant differences between groups, children with a history of SELD generally performed within the normal range on the measures collected. Relations among speech, reading, and metaphonology in the SELD cohort appeared to operate in a manner similar to that seen in groups with typical language development. The implications of these findings for understanding the nature of specific language impairments and for treating early circumscribed language delays are discussed.

Achievement↗
PubMed1997

Immune function in patients with beta thalassaemia receiving the orally active iron-chelating agent deferiprone.

Short-term deferiprone may reduce body iron in some patients with thalassaemia major. Concerns regarding potential immunosuppressive effects of deferiprone have been raised from results of animal studies and case reports in humans. We studied immune function in 57 thalassaemia patients: 36 treated with deferiprone (L1; CP020) and 21 treated with desferrioxamine (DFO). Circulating B lymphocytes were increased in all patient groups. No differences were detected between treatment groups in percentages of circulating lymphocytes, concentrations of IgG, IgM or IgA, specific antibody titres, complement levels, or in vitro lymphocyte proliferation. No clinically important infections were observed in any patient. These data suggest that no clinical or laboratory changes consistent with immuno-suppression or immunodeficiency are observed during deferiprone therapy.

Adolescent↗
PubMed1997

Assessment of physical work load in epidemiologic studies: common measurement metrics for exposure assessment.

There are many possible means of determining exposure ranging from self-reports of physical exposure to measures of muscle activations and estimated spinal loads. In epidemiologic studies, issues of validity make instrumented measures preferable, however issues of cost and practicability tend to force investigators to less costly but less valid and less reliable measures of exposure, such as self-report questionnaires. This paper presents a method by which estimates of exposure from self-report questionnaires, expert observers, work sampling, video analysis and electromyograms can be reported in a common metric, Newtons of force on a tissue, and show, as an example of its application, estimation of spinal compression on auto workers. A common metric allows a flexible approach to selection of measurement methods in occupational settings: no matter which instrument is used the results can be combined to provide an overall picture of exposure. This approach to exposure assessment for the low back allows for comparability across studies and settings.

Automobiles↗
PubMed1996

Detection of JC virus DNA sequence and expression of the viral oncoprotein, tumor antigen, in brain of immunocompetent patient with oligoastrocytoma.

We describe molecular and clinical findings in an immunocompetent patient with an oligoastrocytoma and the concomitant presence of the human papovavirus, JC virus (JCV), which is the etiologic agent of the subacute, debilitating demyelinating disease, progressive multifocal leukoencephalopathy. Histologic review revealed a glial neoplasm consisting primarily of a moderately cellular oligodendroglioma with distinct areas of a fibrillary astrocytoma. Immunohistochemical analysis revealed nuclear staining of tumor cells with antibodies against the viral oncoprotein [tumor antigen (T antigen)], the proliferation marker (Ki67), and the cellular proliferation regulator (p53). Using primers specific to the JCV control region, PCR yielded amplified DNA that was identical to the control region of the Mad-4 strain of the virus. PCR analysis demonstrated the presence of the genome for the viral oncoprotein, T antigen, and results from primer extension studies revealed synthesis of the viral early RNA for T antigen in the tumor tissues. The presence of viral T antigen in the tumor tissue was further demonstrated by immunoblot assay. To our knowledge, this is the first report of the presence of JCV DNA, RNA, and T antigen in tissue in which viral T antigen is localized to tumor cell nuclei and suggests the possible association of JCV with some glial neoplasms.

Antigens, Neoplasm↗
PubMed1995

Statistical prediction of the optimal site for thalamotomy in parkinsonian tremor.

Stereotactic lesions in the thalamus for treatment of parkinsonian tremor are often made at the location where neurons fire at approximately tremor frequency (tremor cells). Some of these cells show a large amount of activity at tremor frequency and are significantly correlated with electromyographic activity (EMG) during tremor. Our analysis of cellular location identifies a cluster of neurons showing activity characterized both by concentration of power at tremor frequency and by significant correlation with EMG. In a retrospective analysis of results in 15 patients, lesions placed within 2 mm of the center of this cluster were uniformly effective in relieving tremor. Therefore, a small lesion targeting this cluster is effective in treatment of parkinsonian tremor.

Brain Mapping↗
PubMed1994

Homework and students with learning disabilities and behavior disorders: a practical, parent-based approach.

This article provides a limited review of the effects of homework on students with disabilities, the essentials of effective homework programs, and variables that affect home-school partnerships. The emphasis is on students with learning disabilities and behavior disorders who are at risk for academic failure and poor school adjustment. The authors introduce the University of Utah Homework Partners series, which highlights three homework packages: a cooperative learning teams-based approach for classrooms, a package to train parents to be positive academic tutors for their children, and a systematic program to train parents in effective homework practices. The latter package is the major focus of this article because it emphasizes home-school partnerships for students with disabilities. Sanity Savers for Parents: Tips for Tackling Homework is a training program that teaches parents how to assess, design, and troubleshoot an effective in-home homework program for their child. The overall emphasis of this program is on practical interventions that are positive and motivating and include a home-to-school link to maximize the generalization of effects for students with learning and behavior disabilities.

Achievement↗
PubMed1994

Using student-managed interventions to increase homework completion and accuracy.

We examined the effectiveness of self-managed individual and group contingency procedures in improving the completion and accuracy rates of daily mathematics homework assignments. A group of sixth-grade students having homework difficulties in mathematics were selected for the study. There was substantial improvement in the amount of homework completed over baseline for a majority of the students, whereas the results for accuracy were mixed. Students who participated in the self-management training made significant gains on standardized measures of academic achievement and curriculum-based measures of classroom performance. Parents also reported significantly fewer problems associated with homework completion following the intervention. Students who were allowed to select their own performance goals made superior improvements in the number of homework assignments returned compared to students who were given a specified goal by the classroom teacher. Parents, subjects, and the classroom teacher responded positively on consumer satisfaction measures following termination of the study.

Journal Article↗
PubMed1993

Injury patterns in motorcycle road racers: experience on the Isle of Man 1989-1991.

We report the first prospective study on the incidence of motorcycle accidents of the world's foremost motorcycle road-racing venue, the Isle of Man. Between 1989 and 1991 there were six meetings during which over 2500 riders took part. Racing on essentially normal country and town roads, the motorcycles can reach speeds in excess of 306 km/h and the average lap record is now 198 km/h. During the study, 175 motorcyclists were injured and 16 were killed (9.1 per cent). The most common injury patterns were soft tissue injury (114 riders), head injury (52) and fractures/dislocations (188), of which one-third were open. The injuries sustained were more frequent and of a greater severity than recreational motorcycling. The casualty rate was 15 times, and the fatality rate 87 times the national figures. Of the 16 fatalities only seven reached hospital alive, despite the use of helicopter air ambulance, and 14 had serious head injuries. No fatality was thought to have been avoidable on review. There were no cervical spine injuries and only two major abdominal injuries. Of the injured riders, 93 (56 per cent) were admitted and there were 170 surgical procedures undertaken on 54 riders.

Adolescent↗
PubMed1993

Weight gain attitudes among pregnant adolescents.

Maternal weight gain is the most important, manageable determinant of infant birth weight among adolescents. Negative attitudes toward weight gain may adversely affect maternal weight gain. We hypothesized that (a) negative attitudes toward pregnancy weight gain are more common among younger pregnant adolescents, and (b) negative attitudes toward pregnancy weight gain adversely affect adolescent maternal weight gain. The study subjects, 99, radially diverse, pregnant 13 through 18 year olds, completed the 18-item, Likert-format, Pregnancy and Weight Gain Attitude Scale. Responses to the questionnaire indicated that most (83.8%) of the adolescents we interviewed had a positive attitude toward pregnancy weight gain when they entered prenatal care. Univariate analyses revealed that attitudes toward weight gain were unrelated to the respondents' ages but inversely related to their prepregnant weights (-0.16; p = 0.06) and the severity of their symptoms of depression (r = -0.26; p = 0.004). Attitudes toward weight gain were also directly related to their family support (r = 0.17; p = 0.06). Weight gain was significantly related to 4 of the 18 scale items but not to the total attitude scale score. We conclude that (a) the developmental task of formulating a positive body image does not foster more negative attitudes toward pregnancy weight gain among younger adolescents; (b) negative weight gain attitudes are most common among heavier adolescents, depressed adolescents, and adolescents who do not perceive their families as supportive; and (c) negative weight gain attitudes could adversely affect pregnancy weight gain.

Adolescent↗
PubMed1992

Oxidation of hemoglobin F is associated with the aging process of neonatal red blood cells.

Previously, we reported that in cord blood there is a population of very dense, surface area-depleted red blood cells (RBC). We hypothesized that oxidative damage might account for the generation of this cell population because Hb F is known to be mildly unstable in vitro. Accordingly, we examined density-separated subpopulations of neonatal red cells searching for evidence of oxidant injury to Hb in vivo. Cord or adult RBC were separated into populations of varying density and an increased amount of membrane-associated globin was found in the densest fraction of cord RBC. Solubilized ghosts from each fraction were analyzed by thiol-disulfide exchange chromatography for the presence of oxidized Hb and spectrophotometrically for the presence of membrane-bound hemichrome. About four times more oxidized Hb was found in unseparated cord RBC than in adult RBC. This difference was most evident in the densest 10-15% RBC subfractions. Membrane-bound hemichrome levels in cord cells were twice those found in adult cells. We found that in cord membrane skeletons there was 2.5 to 9 times as much globin in the dense fraction as compared to the light fraction. Membrane skeletons from dense and light adult RBC differed little from one another. We postulate that membrane (and perhaps membrane skeleton)-associated oxidized Hb is a marker for more generalized oxidative damage, which may create the population of unusually dense cells found in cord blood and ultimately shorten their life span.

Adult↗
PubMed1992

Laparoscopic cholecystectomy in an infant.

Use of the laparoscopic approach in traditionally open procedures has developed rapidly in recent years. Despite this intensive rate of evolution, most procedures have been done in adult patients, with pediatric patients largely excluded. This paper reviews a case report of a laparoscopic cholecystectomy in a 19-month-old male. This effort presents new data and techniques to encourage further investigation into minimally invasive surgery in the pediatric age group.

Cholecystectomy, Laparoscopic↗
PubMed1991

Subepiglottic cyst causing upper airway obstruction in a neonatal calf.

A 14-day-old female Brahman calf was referred because of respiratory stridor since birth. Radiography and endoscopy were used to diagnose a pharyngeal cyst, which was subsequently surgically removed. The subepiglottic location and histopathologic features of the cyst were consistent with origin from an embryologic thyroglossal duct remnant.

Airway Obstruction↗