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Biomedical subjects

J Burke

Publications and source records attributed to J Burke.

At least 91 records · Page 5Linked to original sources
PubMed1995

Diode laser photocoagulation to the vascular retina for progressively advancing retinopathy of prematurity.

AIMS: To estimate the effectiveness of diode laser photocoagulation of the retina posterior to the ridge in eyes with retinopathy of prematurity (ROP). METHODS: Diode laser photocoagulation was applied posterior to the fibrovascular ridge in stage 4a ROP in six eyes of four infants and in advancing stage 3+ in two eyes of one infant. Seven eyes had previously been unsuccessfully treated with diode laser photocoagulation anterior to the ridge. RESULTS: Six eyes of four children had total regression, two eyes of two children had flat maculae with residual peripheral tractional detachment and maintained vision. CONCLUSION: These preliminary results indicate that diode laser photocoagulation posterior to the ridge may be a useful treatment in late stage 3 and stage 4A ROP following failed laser treatment to the avascular retina in threshold stage 3 disease.

Disease Progression↗
PubMed1994

Medial-Golgi retention of N-acetylglucosaminyltransferase I. Contribution from all domains of the enzyme.

We have previously shown that the transmembrane domain and flanking residues of beta-1,2-N-acetylglucosaminyltransferase I (GnTI) can localize a hybrid molecule to medial-Golgi cisternae (Burke, J., Pettitt, J. M., Schachter, H., Sarkar, M., and Gleeson, P.A. (1992) J. Biol. Chem. 267, 24433-24440). Here, we have further examined the contribution of the cytoplasmic tail, transmembrane domain, and the catalytically active, luminal domain of GnTI in medial-Golgi localization, by analyzing the localization of hybrid molecules stably expressed in murine cells. In contrast to wild-type GnTI, which was efficiently localized to the medial-Golgi and not detected at the cell surface, hybrid molecules containing any two of the three domains of GnTI were localized to the medial-Golgi and were also present at low levels at the cell surface. Hybrid molecules containing only the transmembrane domain or the luminal domain of GnTI showed partial Golgi retention together with an increased level of cell surface expression compared with molecules containing two GnTI domains. The cytoplasmic tail independently was unable to retain reporter sequences to the Golgi but increased the ability of constructs containing either the luminal or transmembrane domain of GnTI to localize to the Golgi apparatus. Therefore, all three domains of GnTI contribute significantly to medial-Golgi localization. Furthermore, GnTI hybrid molecules showing increased cell surface expression were more readily extracted in a low salt buffer, suggesting that Golgi localized GnTI differs in physicochemical properties from cell surface GnTI. Based on an aggregation model of localization, we propose that Golgi retention of these hybrid molecules is mediated by the interaction of their GnTI domains with the corresponding domains of endogenous glycosyltransferase aggregates within the Golgi membranes of the transfected cell.

Amino Acid Sequence↗
PubMed1994

Targeting of proteins to the Golgi apparatus.

The Golgi apparatus maintains a highly organized structure in spite of the intense membrane traffic which flows into and out of this organelle. Resident Golgi proteins must have localization signals to ensure that they are targeted to the correct Golgi compartment and not swept further along the secretory pathway. There are a number of distinct groups of Golgi membrane proteins, including glycosyltransferases, recycling trans-Golgi network proteins, peripheral membrane proteins, receptors and viral glycoproteins. Recent studies indicate that there are a number of different Golgi localization signals and mechanisms for retaining proteins to the Golgi apparatus. This review focuses on the current knowledge in this field.

Biological Transport↗
PubMed1994

Effect of age on mortality in coronary artery bypass surgery in New York, 1991-1992.

The purpose of this study was to determine the effect of age on the in-hospital mortality of all 30,972 patients undergoing coronary artery bypass graft (CABG) surgery in New York in 1991 and 1992. Mortality rates were relatively low for patients 40-49, 50-59, and 60-64, 65-69, and 70-74 years old (1.10%, 1.65%, 2.17%, 2.76%, and 3.36%, respectively). However, CABG surgery mortality increased rapidly for patients 75 to 79 years old (5.28%) and patients > or = 80 years old (8.31%). To examine the independent effect of age on mortality after accounting for the effects of other significant risk factors, a multivariate statistical model was developed to identify the significant independent predictors of mortality. Age emerged as 1 of 24 significant predictors, with age > or = 75 demonstrating much higher mortality risk than lesser age. For example, the odds of an 80-year-old patient's dying in the hospital were 3.25 times the odds of a 50-year-old patient's dying in the hospital, assuming all other significant risk factors were identical.

Adult↗
PubMed1994

Priming deficits in patients with dementia of the Alzheimer type.

In a study that replicated the procedures used by Salmon et al. (1988), the effect on stem completion performance of two different semantic orientation tasks has been assessed in patients with Alzheimer's disease. Previously reported findings of impairment in repetition priming in Alzheimer patients were confirmed. Performance was not affected by the nature of the orientation task. No significant correlations were found between explicit and implicit memory tests. The results are discussed in the context of a hypothesized parallel decline in explicit and implicit memory systems.

Aged↗
PubMed1994

Biological evaluation of d2, an algorithm for high-performance sequence comparison.

A number of algorithms exist for searching sequence databases for biologically significant similarities based on the primary sequence similarity of aligned sequences. We have determined the biological sensitivity and selectivity of d2, a high-performance comparison algorithm that rapidly determines the relative dissimilarity of large datasets of genetic sequences. d2 uses sequence-word multiplicity as a simple measure of dissimilarity. It is not constrained by the comparison of direct sequence alignments and so can use word contexts to yield new information on relationships. It is extremely efficient, comparing a query of length 884 bases (INS1ECLAC) with 19,540,603 bases of the bacterial division of GenBank (release 76.0) in 51.77 CPU seconds on a Cray Y/MP-48 supercomputer. It is unique in that subsequences (words) of biological interest can be weighted to improve the sensitivity and selectivity of a search over existing methods. We have determined the ability of d2 to detect biologically significant matches between a query and large datasets of DNA sequences while varying parameters such as word-length and window size. We have also determined the distribution of dissimilarity scores within eukaryotic and prokaryotic divisions of GenBank. We have optimized parameters of the d2 program using Cray hardware and present an analysis of the sensitivity and selectivity of the algorithm. A theoretical analysis of the expectation for scores is presented. This work demonstrates that d2 is a unique, sensitive, and selective method of rapid sequence comparison that can detect novel sequence relationships which remain undetected by alternate methodologies.

Algorithms↗
PubMed1994

Comparison of effects of two interval-training programmes on lactate and ventilatory thresholds.

Twenty-one women subjects were matched in terms of their Vo2max and assigned to one of two groups: (1) training at 30 s; or (2) 2 min with a 1:1 work: relief ratio (1:1 WR) before participating in a 7-week training programme which began at an intensity of 85% Vo2max and increased 5% every two weeks (90% and 95% Vo2max). The subjects trained to exhaustion four times per week. Maximal oxygen consumption (Vo2max), lactate threshold (Tlac) and ventilatory threshold (Tvent) were determined before and after the training programme. After training, there were significant increases (P < 0.05) in Vo2max (5% and 6%), Tlac (19.4% and 22.4%), and Tvent (19.5% and 18.5%). There were no significant group differences on any dependent measure but this research adds support to previous training studies in that a strong correlation (P < 0.05) between Tlac and Tvent is maintained from before to after the test. It was concluded that both formats of high intensity aerobic interval-training produce similar changes in Vo2max, Tlac and Tvent and that these changes appear to be independent of the length of the work interval.

Adult↗
PubMed1994

[Control of Trypanosoma gambiense trypanosomiasis. Evaluation of a strategy based on the treatment of serologically suspected cases with a single dose of diminazene].

A novel method for the control of T.b. gambiense trypanosomiasis was evaluated in an endemic focus of Zaïre where a high incidence had persisted despite massive participation in active case-finding surveys based on lymph node puncture. All inhabitants of 3 villages were examined with a card agglutination serological test (CATT), and parasitological examinations were performed on those who were CATT+. Individuals in whom we detected trypanosomes were treated as usual. A lumbar puncture was carried out on CATT+/parasitology- subjects; those whose cerebrospinal fluid showed more than 3 white blood cell (WBC) per mm3 were treated with a full course of melarsoprol while those with a CSF WBC count between 1 and 3 per mm3 were given a single injection of diminazene (7 mg/kg). Three such surveys were performed, with a 6-month interval, during which 282 "serological suspects" received diminazene, 39 "clinical cases" were given melarsoprol and 82 "parasitological cases" were treated according to standard protocols. The annual incidence of trypanosomiasis decreased rapidly from 10.4-41.1/1.000 inhabitants (mean: 17.6/1.000) during the 10 years before the intervention to 1.1-2.6/1.000 (mean: 1.7/1.000) in the 3 years following the intervention. No major adverse effect was seen with diminazene. Among the 282 serological suspects, an elevated CSF WBC count was later documented in 12 individuals, who were all cured with melarsoprol. The incidence increased 5 years after the intervention (7.1/1.000 in 1992), which may have been avoided had we carried out similar interventions in adjacent foci.

Agglutination Tests↗
PubMed1994

Workplace advocacy.

Explore the source record for details and available documents.

American Nurses' Association↗
PubMed1993

Antibody to an abnormal protein in amyotrophic lateral sclerosis identifies Lewy body-like inclusions in ALS and Lewy bodies in Parkinson's disease.

Ubiquitinated cytoplasmic inclusions are a characteristic feature of the neuronal pathology of neurodegenerative diseases. Immunocytochemical techniques have identified intermediate filaments associated with ubiquitin-immunoreactive inclusions in Alzheimer's disease (AD), Parkinson's disease (PD), and Pick's disease; however, no core protein has been detected in the ubiquitinated inclusions in amyotrophic lateral sclerosis (ALS). The pathogenesis of these inclusions is not known, but the inclusion may result from an accumulation of an abnormal proteins. Here we report a novel protein of 32.5 kDa detected by polyacrylamide gel electrophoresis, in the spinal cord in ALS patients. A polyclonal antibody raised against this protein and used for Western blotting, suggests that the novel protein is related to actin. Immunocytochemical studies using this antibody indicate that the protein is found in Lewy body-like inclusions in anterior horn cells of ALS, and in Lewy bodies in the substantia nigra in PD.

Actins↗
PubMed1993

Drug-induced disorders of glucose tolerance.

PURPOSE: To review the medications that influence glucose metabolism and to examine the mechanisms of these medications on glucose metabolism. DATA SOURCES: Data were obtained from a MEDLINE search back to 1966 and included animal and human studies published in the English language. STUDY SELECTION: Approximately 80% of original publications were included after review by the authors. Case reports were included if they provided additional information. DATE EXTRACTION: The original data from the literature were included on the basis of independent extraction by the authors. DATA SYNTHESIS: Many common therapeutic agents influence glucose metabolism. Multiple mechanisms of action on glucose metabolism exist through pancreatic, hepatic, and peripheral effects. Based on circumstances at the time of use, a drug may cause both hyper- and hypoglycemia in a patient. The patient's previous pancreatic reserve, nutritional state, use of other medication, or exposure to alcohol may influence the direction of the plasma glucose alterations. CONCLUSION: Hyperinsulinemia and insulin resistance form an intrinsic component of diabetes, hyperlipidemia, and atherosclerotic vascular disease (syndrome X). The induction of hyperinsulinemia and insulin resistance by medication may therefore counteract intended benefits. An extensive review of recent medication in patients with disorders of glucose tolerance and the avoidance of polypharmacy are recommended. It is prudent to monitor plasma glucose values when it is not possible to avoid prescription of medication with known effects on carbohydrate metabolism.

Animals↗
PubMed1993

Exclusion of linkage between schizophrenia and the D2 dopamine receptor gene region of chromosome 11q in 112 Irish multiplex families.

A leading theory hypothesizes that schizophrenia arises from dysregulation of the dopamine system in certain brain regions. As this dysregulation could arise from abnormal expression of D2 dopamine receptors, the D2 receptor gene (DRD2) on chromosome 11q is a candidate locus for schizophrenia. We tested whether allelic variation at DRD2 and five surrounding loci cosegregated with schizophrenia in 112 small- to moderate-size Irish families containing two or more members affected with schizophrenia or schizoaffective disorder, defined by DSM-III-R. Evidence of linkage was assessed using varying definitions of illness and modes of transmission. Assuming genetic homogeneity, linkage between schizophrenia and large regions of 11q around DRD2 could be strongly excluded. Assuming genetic heterogeneity, variation at the DRD2 locus could be rejected as a major risk factor for schizophrenia in more than 50% of these families for all models tested and in as few as 25% of the families for certain models. The DRD2 linkage in fewer than 25% of these families could not be excluded under any of the models tested. Our results suggest that the major component of genetic susceptibility to schizophrenia is not due to allelic variation at the DRD2 locus or other genes in the surrounding chromosomal region.

Alleles↗
PubMed1993

Extracorporeal shock wave lithotripsy induces the release of prostaglandins which increase ureteric peristalsis.

The aim of this study was to identify the changes in secretion of prostaglandins into the urinary tract as a result of treatment by extracorporeal shock wave lithotripsy (ESWL) and to determine their effects on ureteric motility. Sixteen patients with renal or upper ureteric calculi were studied. A peripheral blood and urine sample was collected immediately before and after ESWL, with further samples taken 24 h later. The following variables were assessed by radioimmunoassay:prostaglandin E2 (PGE2), prostaglandin F1 alpha (PGF1 alpha), and thromboxane B2 (TXB2). An in vitro canine study was then designed to study the activity of TXB2, PGF1 alpha and PGE2 on an isolated intact canine ureter model. Significant elevations of TXB2 were found immediately after ESWL in both serum and urine, which fell almost to pre-treatment levels by 24 h. PGF1 alpha levels showed significant elevations at 24 h but no immediate increase as seen with TXB2. In contrast, PGE2 levels were unchanged in the urine but significantly decreased in the serum. In vitro studies showed that both TXB2 and PGF1 alpha repeatedly produced an increased frequency of ureteric contraction. ESWL results in the release of prostaglandins from the urinary tract which are shown to cause increased ureteric peristalsis.

Adult↗