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Biomedical subjects

R Flanagan

Publications and source records attributed to R Flanagan.

15 recordsLinked to original sources
PubMed1999

Multiple logistic regression analysis of plasma paraquat concentrations as a predictor of outcome in 375 cases of paraquat poisoning.

Successful prediction of who may survive paraquat poisoning can prevent inappropriately aggressive treatment in those who have little hope of survival and those only minimally poisoned. We examined case records of patients admitted to one poisoning treatment unit over the last 5 years, and the English and French language literature on paraquat poisoning. Data were recorded from all patients where outcome and timed plasma paraquat concentrations were present. Of 375 patients (113 M, 62 F, 200 unknown), mean age 38.3 years (range 1-87 years), 49 had evidence of renal toxicity, and 41 received haemodialysis or charcoal haemoperfusion; 61 developed pulmonary sequelae; and 44 had lesions in the upper gastrointestinal tract. Median time from ingestion to death in the 241 deaths reported was 270 h (range 3-720 h). We plotted log(plasma paraquat concentration) against log(h since ingestion). The predicted probability of survival for any specified time and concentration was exp(logit)/[1 + exp(logit)], where logit = 0.58-2.33 x log(plasma paraquat)-1.15 x log(h since ingestion). This equation may be helpful in predicting who will survive after ingestion of paraquat up to at least 200 h after ingestion, and can now be used as a research tool for studies on efficacy of treatment of paraquat poisoning.

Adolescent↗
PubMed1999

Objective and projective personality assessment: the TEMAS and the Behavior Assessment System for Children, self-report of personality.

The TEMAS and Self-report of Personality of the Behavior Assessment System for Children were administered to 71 youngsters aged 8 to 13 years. Preliminary data suggest that, although the two measures assess several similarly named constructs, the data are complementary. This appears to reflect the fact that the TEMAS Personality Functions measure children's skills in coping with emotionally laden situations, whereas the Behavior Assessment System for Children measures the emotion or skill in question independent of situational context.

Adaptation, Psychological↗
PubMed1997

Measurement of nucleic acid concentrations using the DyNA Quant and the GeneQuant.

Molecular biology is now a routine tool in almost all biological research fields. With the exponential growth in the number of molecular biological techniques, there is a recognizable need for sensitive, accurate and precise quantitation of nucleic acids. We present here two complementary instruments designed for the quantitation of nucleic acids, the GeneQuant II and the DyNA Quant 200 Fluorometer. The GeneQuant II can rapidly determine the UV absorbance of a solution and display the calculated DNA, RNA or protein concentration. In addition, the GeneQuant can display calculated melting temperatures for a given DNA oligonucleotide base sequence, a useful feature for primer design. The DyNA Quant 200 quantitates DNA on the basis of the fluorescent Hoechst 33258 dye/double-stranded (ds)DNA assay. Upon binding to dsDNA, the spectral properties of the dye change such that it becomes highly fluorescent at 460 nm when excited at 365 nm. The assay has proven to be a specific and sensitive alternative method for DNA quantitation, particularly for unpurified DNA samples. Together, the GeneQuant II and the DyNA Quant 200 are a cost-effective and convenient solution to the routine protein and nucleic acid quantification needs of the molecular biologist.

Bisbenzimidazole↗
PubMed1995

Temporal integration differences between crossed and uncrossed stereoscopic mechanisms.

In this study, we investigated temporal integration of disparity information for crossed and uncrossed stereopsis. Across three experiments, exposure duration thresholds were measured for stereoscopic stimuli created from dynamic random-dot stereograms. In Experiment 1, an investigation of disparity detection showed that detection thresholds were equal for the crossed and uncrossed directions. In Experiment 2, an examination of duration limits for depth perception showed that critical durations were lower, and depth more veridical, for crossed depth than for uncrossed depth. In Experiment 3, an investigation of depth discrimination revealed that discrimination thresholds were lower for crossed depth than for uncrossed depth. These results suggest that crossed and uncrossed mechanisms differ in terms of their temporal integration properties at processing levels involving the computation and discrimination of depth.

Depth Perception↗
PubMed1993

The milk-alkali syndrome. A reversible form of acute renal failure.

The milk-alkali syndrome became rare with the advent of modern ulcer therapy with nonabsorbable antacids, histamine2 blockers, and sucralfate. An increased frequency of this syndrome seems likely with the growing popularity of the use of calcium carbonate as an antacid or as calcium supplementation to prevent osteoporosis. We treated five patients who had six episodes of the milk-alkali syndrome; four of these cases were diagnosed between 1990 and 1992. All patients were ingesting massive quantities of calcium and absorbable alkali and were unaware of the toxic effects of these compounds. All patients presented with the triad of hypercalcemia, metabolic alkalosis, and renal failure. All metabolic abnormalities were corrected, and renal function improved with appropriate supportive measures and cessation of calcium and alkali ingestion. In two patients, the renal failure was so severe that dialysis was necessary. In four patients, either the serum amino-terminal parathyroid hormone or 1,25-dihydroxycholecalciferol levels were appropriately decreased in response to hypercalcemia. The serum carboxy-terminal parathyroid hormone levels were increased because of renal failure. Since both physicians and patients are often unaware of the calcium and alkali content of many nonprescription medicines, the diagnosis of the milk-alkali syndrome, a reversible cause of renal failure, can be missed if a detailed history of such intake is not elicited. Measurement of the serum amino-terminal parathyroid hormone and 1,25-dihydroxycholecalciferol levels may help differentiate milk-alkali syndrome from primary hyperparathyroidism.

Acute Kidney Injury↗
PubMed1993

Nontuberculous mycobacterial infections in continuous ambulatory peritoneal dialysis patients.

Nontuberculous mycobacterial infections are a rare but clinically important cause of infections in continuous ambulatory peritoneal dialysis (CAPD) patients. We describe seven cases of catheter-related nontuberculous mycobacterial infections associated with CAPD. Six patients had Mycobacterium fortuitum infections and one had a Mycobacterium kansasii infection. Three patients presented with peritonitis, three presented with exit site infections, and one developed an infection at the exit site after catheter removal. There were no specific clinical findings that differentiated these infections from those caused by common bacterial pathogens. Initial routine peritoneal dialysis fluid and exit site cultures were negative in two patients and grew M fortuitum in four patients and M kansasii in one patient. M fortuitum and M kansasii were sensitive to amikacin, and M fortuitum was sensitive to ciprofloxacin when tested. Sensitivities to other antibiotics were variable. All patients were treated with a combination of antibiotics from 3 weeks to 6 months. Catheter removal was necessary for cure of the infection in all patients with peritonitis and in a majority of patients with exit site infections. The majority of patients changed to hemodialysis after catheter removal. Two patients remained on CAPD, with follow-up ranging from 2 months to 4 years. One patient has received a successful renal transplant. In conclusion, M fortuitum is the most common nontuberculous mycobacterial catheter-related infection in CAPD patients. Nontuberculous mycobacterial infections should be considered in the differential diagnosis of any culture-negative infection associated with CAPD. In patients with infections secondary to M fortuitum, our findings suggest that amikacin and ciprofloxacin are the initial antibiotics of choice until antibiotic sensitivities are available.

Aged↗
PubMed1992

In vivo measurement of atrial natriuretic peptide receptors using nuclear imaging.

We have successfully visualized atrial natriuretic peptide (ANP) receptors in vivo using nuclear imaging. 123I-Labelled ANP, injected in green vervet monkeys, was rapidly bound to ANP receptors in the kidneys and lungs. That the observed uptake was receptor mediated was demonstrated with competition studies using simultaneous injection of unlabelled ANP 99-126. It was possible to distinguish between the ANP receptor subtypes by the use of selective antagonists. Thus coinjection of ANP 102-121-des[Gln, Ser, Gly, Leu, Gly] (C-ANP), an ANP analog that selectively binds to the ANP C-receptor, decreased uptake in the kidneys by 50% but increased relative uptake in the lungs and soft tissues. This method permits for the first time, the dynamic in vivo analysis of ANP receptors and their interaction with endogenous ligand. Differences and changes in local ANP receptor concentrations and occupancy could be detected. Since ANP receptor density and affinity are influenced by various physiological and pathological conditions, clinical and diagnostic applications seem possible.

Animals↗
PubMed1992

Shyness, egocentricity, and psychopathology: their relationships among nonhospitalized individuals and mental hospital patients.

To investigate the relationship between shyness and egocentricity in both psychiatric (hospitalized) and nonhospitalized groups, 162 adult men and women diagnosed as paranoid or undifferentiated schizophrenic, and a control group of 162 nonhospitalized individuals matched for age and gender were studied. Shyness was assessed on the Social Reticence Scale and egocentricity by the Self-focus Sentence Completion. Analysis indicated that the patients were more shy than nonhospitalized individuals. Paranoid schizophrenics were not different from undifferentiated schizophrenics on egocentricity and the Self-focus Sentence Completion subscales. Nonhospitalized individuals and the mental hospital patients were egocentric on the Self-focus Sentence Completion. For this reason, relationships among shyness, egocentricity, and psychopathology could not be demonstrated.

Adolescent↗
PubMed1990

The requirement for platelets in allergen-induced late asthmatic airway obstruction. Eosinophil infiltration and heightened airway responsiveness in allergic rabbits.

In these studies, we have used an allergic rabbit model to investigate the role of platelets in the late asthmatic response (LAR) by depleting platelets with a guinea pig antirabbit platelet antiserum (APAS). Allergen exposure of immunized rabbits pretreated with normal guinea pig serum (NGPS) to serve as a control resulted in an early- and late-phase obstructive airway response that persisted for 6 h. When the immunized animals were pretreated with APAS, the magnitude of the LAR in terms of dynamic compliance was reduced by 86.2% (p less than 0.03), but there was no difference in the early response curve. Allergen challenge of animals treated with NGPS resulted in an increased bronchial responsiveness to inhaled histamine: PD50 Cdyn geometric mean +/- SEM before, 2.36 mg/ml (3.43-1.64); after, 0.60 mg/ml (0.67-0.54) (p less than 0.01). PD50 RL before, 1.78 mg/ml (2.4-1.32); after, 0.58 mg/ml (0.81-0.47) (p less than 0.05). In contrast, when animals were treated with APAS, there was a significant inhibition of allergen-induced airway hyperresponsiveness to inhaled histamine: PD50 Cdyn geometric mean +/- SEM before, 1.42 mg/ml (2.06-0.98); after, 1.10 mg/ml (1.41-0.86) (p less than 0.4). PD50 RL before, 1.62 mg/ml (2.22-1.39); after, 1.05 mg/ml (1.35-0.82) (p greater than 0.4). Analysis of bronchoalveolar lavage fluid revealed an increase in the number of neutrophils and eosinophils after allergen exposure in control animals (p less than 0.01). However, in animals rendered thrombocytopenic, the number of eosinophils, but not neutrophils, was significantly reduced (p less than 0.03).(ABSTRACT TRUNCATED AT 250 WORDS)

Allergens↗
PubMed1989

Replication timing of 10 developmentally regulated genes in Physarum polycephalum.

We have tested the hypothesis which stipulates that only early-replicating genes are capable of expression. Within one cell type of Physarum - the plasmodium - we defined the temporal order of replication of 10 genes which were known to be variably expressed in 4 different developmental stages of the Physarum life cycle. Southern analysis of density-labeled, bromodesoxyuridine-substituted DNA reveals that 4 genes presumably inactive within the plasmodium, were not restricted to any temporal compartment of S-phase: 1 is replicated in early S-phase, 2 in mid S-phase and 1 in late S-phase. On the other hand, 4 out of 6 active genes analysed are duplicated early, with the first 30% of the genome. Surprisingly, the two others active genes are replicated late in S-phase. By gene-dosage analysis, based on quantitation of hybridization signals from early and late replicating genes throughout S-phase, we could pinpoint the replication of one of these two genes at a stage where 80-85% of the genome has duplicated. Our results demonstrate that late replication during S-phase does not preclude gene activity.

Blotting, Southern↗
PubMed1984

Diazepam tolerance: effect of age, regular sedation, and alcohol.

The dose of intravenous diazepam required for sedation was estimated in a series of 78 patients aged 17-85 years given the drug for dental and endoscopic procedures. Multiple regression analysis showed a significant correlation (r = 0.71; p less than 0.001) between dose and age, body weight, the taking of regular sedation, and the taking of more than 40 g alcohol daily, but there were no differences in the doses required between men and women, smokers and non-smokers, inpatients and outpatients, or dental and endoscopy patients. Patients aged 80 required an average dose of 10 mg and patients aged 20 an average dose of 30 mg, and the dose required was much higher in those receiving regular sedation or having a high alcohol intake. Plasma total and free diazepam concentrations were measured in the second half of the series of patients (n = 37). Plasma concentrations required for sedation fell twofold to threefold between the ages of 20 and 80 and were significantly higher in those taking regular sedation or alcohol. Differences in the acute response to diazepam appeared to be due to differences in the sensitivity of the central nervous system (pharmacodynamic tolerance) rather than to differences in pharmacokinetic factors.

Adolescent↗