Search PubMed⌕ Search

Biomedical subjects

J Burns

Publications and source records attributed to J Burns.

At least 73 records · Page 4Linked to original sources
PubMed1997

Combined medical and surgical treatment after acute spinal cord injury: results of a prospective pilot study to assess the merits of aggressive medical resuscitation and blood pressure management.

The optimal management of acute spinal cord injuries remains to be defined. The authors prospectively applied resuscitation principles of volume expansion and blood pressure maintenance to 77 patients who presented with acute neurological deficits as a result of spinal cord injuries occurring from C-1 through T-12 in an effort to maintain spinal cord blood flow and prevent secondary injury. According to the Intensive Care Unit protocol, all patients were managed by using Swan-Ganz and arterial blood pressure catheters and were treated with immobilization and fracture reduction as indicated. Intravenous fluids, colloid, and vasopressors were administered as necessary to maintain mean arterial blood pressure above 85 mm Hg. Surgery was performed for decompression and stabilization, and fusion in selected cases. Sixty-four patients have been followed at least 12 months postinjury by means of detailed neurological assessments and functional ability evaluations. Sixty percent of patients with complete cervical spinal cord injuries improved at least one Frankel or American Spinal Injury Association (ASIA) grade at the last follow-up review. Thirty percent regained the ability to walk and 20% had return of bladder function 1 year postinjury. Thirty-three percent of the patients with complete thoracic spinal cord injuries improved at least one Frankel or ASIA grade. Approximately 10% of the patients regained the ability to walk and had return of bladder function. As of the 12-month follow-up review, 92% of patients demonstrated clinical improvement after sustaining incomplete cervical spinal cord injuries compared to their initial neurological status. Ninety-two percent regained the ability to walk and 88% regained bladder function. Eighty-eight percent of patients with incomplete thoracic spinal cord injuries demonstrated significant improvements in neurological function 1 year postinjury. Eighty-eight percent were able to walk and 63% had return of bladder function. The authors conclude that the enhanced neurological outcome that was observed in patients after spinal cord injury in this study was in addition to, and/or distinct from, any potential benefit provided by surgery. Early and aggressive medical management (volume resuscitation and blood pressure augmentation) of patients with acute spinal cord injuries optimizes the potential for neurological recovery after sustaining trauma.

Adult↗
PubMed1996

Distribution of pituitary adenylate cyclase activating polypeptide (PACAP) immunoreactivity in the hypothalamus and extended amygdala of the rat.

Pituitary adenylate cyclase activating polypeptide (PACAP) is found in two forms of 27 and 38 amino acids (PACAP-27 and PACAP-38 respectively) in the mammalian central nervous system. Using antibodies to these two forms of PACAP, we examined the distribution of PACAP immunoreactivity in the rat hypothalamus and a number of extrahypothalamic areas. The patterns of immunostaining for PACAP-27 and PACAP-38 were similar: prominent terminal labelling was present in the retrochiasmatic area, median eminence, and posterior periventricular nucleus of the hypothalamus as well as the bed nucleus of the stria terminalis and amygdaloid complex. After colchicine treatment, immunopositive cell bodies were found in the preoptic region of the periventricular zone of the hypothalamus, the suprachiasmatic and paraventricular hypothalamic nuclei, neural structures adjacent to the median eminence (including the retrochiasmatic area, arcuate nucleus, ventromedial hypothalamus, and tuber cinereum), and the lateral mammillary and supramammillary nuclei. In all these areas, immunolabelling appeared specific since it was abolished by preabsorption of primary antisera with the appropriate PACAP peptide. However, the number of immunopositive cells in the suprachiasmatic nucleus was also reduced by preabsorption of PACAP-27/38 antisera with vasoactive intestinal polypeptide, suggesting that a subpopulation of cells in the suprachiasmatic nucleus express a peptide which has significant sequence homology with both PACAP-27/38 and vasoactive intestinal polypeptide. The distribution of PACAP immunoreactivity throughout the hypothalamus, bed nucleus of the stria terminalis, and amygdala suggests the involvement of PACAP in a number of processes including limbic, autonomic, and neuroendocrine functions as well as regulation of the circadian pacemaker.

Amygdala↗
PubMed1996

Requirement for CD4+ T cells in the gammadelta T cell proliferative response to Daudi Burkitt's lymphoma.

Daudi Burkitt's lymphoma cells stimulate the proliferation of Vgamma2 Vdelta2 T cells in human peripheral blood mononuclear cells (PBMC). Transfection studies have established that the gammadelta T cell receptor is sufficient for recognition of a ligand associated with Daudi cells. Since other studies have demonstrated the need for cooperation between alphabeta T cells and Vgamma2 Vdelta2 T cells in the proliferative response to mycobacterial antigens, we used human, unfractionated PBMC and PBMC depleted of specific T cell subsets to determine whether the gammadelta T cell response to Daudi cells also requires cooperation between alphabeta and gammadelta T cells. In the current study, we demonstrate that depletion of CD4+ T cells substantially reduces the overall proliferative response of PBMC to Daudi cells and subsequent gammadelta T cell expansion. IL-2 production by PBMC in response to Daudi cells was also decreased by depletion of CD4+ T cells, but not by depletion of CD8+ or gammadelta T cells. In the CD4+ T-cell-depleted PBMC, proliferation in response to Daudi cells was restored by the addition of IL-2. These data stress the importance of cooperation between alphabeta and gammadelta T cells in the response to some complex antigens.

B-Lymphocytes↗
PubMed1996

Induction of V gamma 2 V delta 2 T cell proliferation by activated antigen-specific CD4+ T cells and IL-2.

Human gamma delta T cells respond to a wide range of ligands including some T lymphocyte cellular antigens associated with viral infection. In the present study we examined the participation of gamma delta T cells in the proliferative response that is induced in human peripheral blood mononuclear cells (PBMC) by activated, antigen-reactive, CD4+ T cells. Activated, irradiated, myelin basic protein (MBP)-specific T cells stimulate brisk proliferation when cultured with freshly isolated, autologous PBMC. Determination of the phenotype of the responding PBMC T cells revealed a prominent expansion of gamma delta T cells, principally of the V gamma 2 subset. There was only minimal proliferation of PBMC following culture with irradiated, MBP-specific T cells that had not been recently activated. However, addition of rIL-2 to cultures of PBMC and nonstimulated MBP-specific T cells restored proliferation and the expansion of the gamma delta T cells. IL-2 alone did not mediate this effect. While MBP was a convenient antigen to use in these experiments, similar gamma delta T cell expansion in vitro was noted using activated, CD4+ T cells reactive with an exogenous antigen, Candida. In additional experiments, gamma delta-enriched T cell lines and certain V gamma 2 T cell clones continued to respond to activated but not to nonstimulated, CD4+ T cells. Overall, this study suggests that V gamma 2 V delta 2 T cells may proliferate as a consequence of the activation of CD4+ T cells. At least one ligand associated with T cell activation is required in addition to IL-2.

CD4-Positive T-Lymphocytes↗
PubMed1996

Infrequent alterations of the p53 gene in rat skin cancers induced by ionizing radiation.

Radiation carcinogenesis almost certainly involves multiple genetic alterations. Identification of such genetic alterations would provide information to help understand better the molecular mechanism of radiation carcinogenesis. The energy released by ionizing radiation has the potential to produce DNA strand breaks, major gene deletions or rearrangements, and other base damages. Alterations of the p53 gene, a common tumour suppressor gene altered in human cancers, were examined in radiation-induced rat skin cancers. Genomic DNA from a total of 33 rat skin cancers induced by ionizing radiation was examined by Southern blot hybridization for abnormal restriction fragment patterns in the p53 gene. An abnormal p53 restriction pattern was found in one of 16 cancers induced by electron radiation and in one of nine cancers induced by neon ions. The genomic DNA from representative cancers, including the two with an abnormal restriction pattern, was further examined by polymerase chain reaction amplification and direct sequencing in exons 5-8 of the p53 gene. The results showed that one restriction fragment length polymorphism (RFLP)-positive cancer induced by electron radiation had a partial gene deletion which was defined approximately between exons 2-8, while none of the other cancers showed sequence changes. Our results indicate that the alterations in the critical binding region of the p53 gene are infrequent in rat skin cancers induced by either electron or neon ion radiation.

Animals↗
PubMed1996

Necropsy study of the association between sudden cardiac death, cardiac isoenzymes and contraction band necrosis.

AIMS: To assess whether a quantitative analysis of myocardial contraction bands could aid the postmortem identification of early myocardial infarction, especially if used in conjunction with cardiac isoenzyme activities. METHODS: Sixty four coroner's necropsies were grouped by gross and histological findings into 26 cases of definite non-cardiac death, 12 cases of definite myocardial infarction and 26 cases in which there was occlusive coronary artery atheroma, but no demonstrable evidence of infarction. Using multiple sections of left ventricular myocardium stained with Heidenhain's iron haematoxylin, the number of myocardial cells containing contraction bands per unit area was quantified. The results were analysed statistically using logistic regression, and were then compared and combined with results from the statistical analysis of postmortem cardiac isoenzymes that had recently been undertaken on the same cases. RESULTS: The number of cells containing contraction bands per unit area was higher in cases of definite myocardial infarction compared with those of non-cardiac deaths. In addition, cases of occlusive coronary artery atheroma only could be identified, indicating the presence of early myocardial infarction. The accuracy of this identification could be improved by combining these results with the results from the statistical analysis of postmortem cardiac isoenzymes. CONCLUSION: The quantitative assessment of myocardial contraction band necrosis can provide useful additional information in cases of sudden death, where myocardial infarction is suspected but not identified on routine histological staining. The value of the information obtained is increased when used in conjunction with the postmortem measurement of cardiac isoenzyme activities.

Coronary Artery Disease↗
PubMed1996

Distance estimation by foraging honeybees

Honeybees are widely believed to assess feeder distances by the energy spent on foraging flights. However, a critical review of this 'energy hypothesis' reveals many inconsistencies in the experiments from which it was derived. In fact, new evidence shows that the energy hypothesis cannot be correct. Foragers loaded with weights do not overestimate distance, as indicated by their waggle dances performed upon return to the hive. Bees that climb to a feeder on top of a high building (50 m) signal the same distance as hive mates that visit an equidistant feeder at ground level. Foragers visiting a feeder suspended from a balloon at 70 m from their hive underestimate the distance flown dramatically when the balloon lifts the feeder from ground level to 90 m, even though the energy required to reach the feeder increases considerably. Foragers from a hive situated on a high building (50 m) that fly to a feeder on the roof of another high building (34 m) signal a much shorter distance than the actual distance flown. We propose instead an 'optical flow hypothesis': bees use the speed of retinal image motion perceived from the ground to estimate the distance flown. Flight altitude is important for distance estimation by retinal image flow, because objects move faster and farther across the retina when the bee flies closer to the ground. When the forager's flight behavior is considered, the optical flow hypothesis does not conflict with previous findings.

Journal Article↗
PubMed1995

Feds come knocking in search of home-care fraud.

Home care has become a target for federal investigators looking for ways to reduce the amount of money Medicare doles out to fraudulent providers. Companies and executives in the multibillion-dollar industry are facing charges ranging from filing bogus claims to money laundering.

Criminal Law↗
PubMed1995

Workers strike back.

Frustrated by layoffs and new rules, healthcare workers are striking back. Nurses, such as those rallying in Seattle, are leading the charge. Interest in unions is rising. Specifically, unions have made inroads in efforts to organize nursing home workers, p. 28.

Data Collection↗