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Biomedical subjects

D Burnham

Publications and source records attributed to D Burnham.

14 recordsLinked to original sources
PubMed2006

Emotional prosodic processing in auditory hallucinations.

Deficits in emotional prosodic processing, the expression of emotions in voice, have been widely reported in patients with schizophrenia, not only in comprehending emotional prosody but also expressing it. Given that prosodic cues are important in memory for voice and speaker identity, Cutting has proposed that prosodic deficits may contribute to the misattribution that appears to occur in auditory hallucinations in psychosis. The present study compared hallucinating patients with schizophrenia, non-hallucinating patients and normal controls on an emotional prosodic processing task. It was hypothesised that hallucinators would demonstrate greater deficits in emotional prosodic processing than non-hallucinators and normal controls. Participants were 67 patients with a diagnosis of schizophrenia or schizoaffective disorder (hallucinating=38, non-hallucinating=29) and 31 normal controls. The prosodic processing task used in this study comprised a series of semantically neutral sentences expressed in happy, sad and neutral voices which were rated on a 7-point Likert scale from sad (-3) through neutral (0) to happy (+3). Significant deficits in the prosodic processing tasks were found in hallucinating patients compared to non-hallucinating patients and normal controls. No significant differences were observed between non-hallucinating patients and normal controls. In the present study, patients experiencing auditory hallucinations were not as successful in recognising and using prosodic cues as the non-hallucinating patients. These results are consistent with Cutting's hypothesis, that prosodic dysfunction may mediate the misattribution of auditory hallucinations.

Adult↗
PubMed1999

Effects of the bradykinin antagonist Bradycor (deltibant, CP-1027) in severe traumatic brain injury: results of a multi-center, randomized, placebo-controlled trial. American Brain Injury Consortium Study Group.

A phase II prospective, randomized, double blind clinical trial of Bradycor, a bradykinin antagonist, was conducted at 31 centers within North America in severely brain injured patients. Patients of Glasgow Coma Score (GCS) 3-8 (n = 139) with at least one reactive pupil were randomized to receive either Bradycor, 3 microg/kg/min or placebo as a continuous intravenous infusion for 5 days, with the infusion beginning within 12 h of the injury. The primary objective was to assess the efficacy of a continuous infusion of Bradycor (3.0 mc/kg/min) in preventing elevation of intracranial pressure (ICP). Other efficacy measures included the effect of Bradycor on the Therapy Intensity Level (TIL), mortality, and functional outcome. A secondary objective was to evaluate the safety of Bradycor in patients with severe brain injury. Randomization was carried out according to a computer generated randomization list. Patients were followed for the first 14 days of hospitalization with long-term outcome assessed at 3 and 6 months after injury. During the infusion and while the ICP monitor was in place, ICP measurements were recorded hourly along with blood pressure and heart rate. A modified version of the TIL was used to record therapeutic interventions hourly, while the ICP was being monitored. Outcome was assessed at 3 and 6 months after injury using the Glasgow Outcome Score (GOS). Bradycor was well tolerated in this patient population, and no adverse events were attributable to the compound. Although positive trends were seen for both ICP and TIL in the Bradycor group, these differences analyzed on a daily basis were not significant. However, a mixed model of variance which included treatment, day, treatment by day interaction, age and GCS revealed that the percentage time ICP of >15 mm Hg on days 4 and 5 was significantly lower in the Bradycor group compared to placebo (p = 0.035). There were fewer deaths in the Bradycor group, which had a 28-day all cause mortality of 20% versus 27% on placebo. Patients treated with Bradycor showed a 10.3% improvement in favorable outcome at 3 months and a 12% improvement in dichotomized GOS at 6 months (p = 0.26). The consistent positive trends seen in ICP, TIL, neuropsychological tests, and, most importantly, 3- and 6-month GOS provide supportive evidence that a bradykinin antagonist may play a neuroprotective role in severe brain injury.

Adolescent↗
PubMed1998

Effect of histamine-2 receptor antagonists on blood alcohol levels: a meta-analysis.

OBJECTIVE: To determine the effect, if any, of histamine type 2 receptor antagonists (H2RAs) on serum alcohol levels under various conditions including type of H2RA receptor antagonist, alcohol dose, and fed status of the subject. STUDY DESIGN: Meta-analysis of the published literature. DATA SOURCES: Studies were identified by MEDLINE (January 1982 through December 1997) using the key words H2 receptor antagonists and alcohol. Other studies were identified by reviewing bibliographies of retrieved articles and by discussion with colleagues. STUDY SELECTION: Studies were selected if they involved the coadministration of H2RAs and alcohol in healthy, human volunteers. Studies that may have addressed this goal but were performed in another context, for instance the measurement of ulcer healing, were excluded. DATA EXTRACTION: Data were extracted on the design, number of participants, participant characteristics, type and dose of H2RA administered, serum alcohol levels (measured as Cmax) along with standard deviations, dose of alcohol received, and fed or fasted status of participants. Alcohol dose was arbitrarily divided into low dose (< or = 0.5 g/kg body weight) versus high dose (> 0.5 g/kg body weight). In addition, studies involving ranitidine and cimetidine were stratified by sample size into small (n < or = 10) versus not small (n > 10). MEASUREMENTS AND MAIN RESULTS: Twenty-four trials met selection criteria. Small elevations in Cmax were noted when cimetidine (2.71 mg/DL; 95% confidence internal [CI] 1.60, 3.83) or ranitidine (6.95 mg/DL; 95% CI 5.83, 8.08) were coadministered with alcohol. No such differences were noted for famotidine (0.28 mg/DL; 95% CI -1.24, 1.80) or nizatidine (2.33 mg/DL;, 95% CI -0.06, 4.72). The elevation detected with cimetidine and ranitidine was most pronounced in smaller studies (n < 10). Separate analyses investigating the effect of alcohol dose and fed or fasted status of participants revealed no clinically important differences. CONCLUSIONS: Cimetidine and ranitidine, but not the other H2RAs, can cause small elevations of serum alcohol level when alcohol and drug are administered concurrently. Studies with larger numbers of participants were less likely to demonstrate this effect. Relative to accepted, legal definitions of intoxication, the effect of any H2RA on blood alcohol level is unlikely to be clinically relevant.

Cimetidine↗
PubMed1998

Efficacy studies of paroxetine in panic disorder.

The optimal assessment of treatment outcome for studies assessing the efficacy of treatments for panic disorder has been a controversial topic. A recent National Institute of Mental Health (NIMH)-sponsored consensus conference addressed this important topic, and a summary paper regarding assessment of essential elements of the disorder resulted. Among other conclusions, it was agreed that several different domains should be considered as essential. This article reviews three pivotal studies assessing the efficacy of paroxetine for the treatment of panic disorder, and evaluates these studies for inclusion of those variables considered essential. Additionally, some data were reanalyzed to determine the percentage of individuals in these studies who are unequivocal responders (i.e., were both panic-free and rated on global assessment as responders). A longer-term treatment and relapse study is also mentioned briefly.

Antidepressive Agents, Second-Generation↗
PubMed1993

Visual recognition of mother by young infants: facilitation by speech.

Infants recognise their mother's voice at birth but appear not to recognise visual-only presentations of her face until around 3 months. In a series of experiments visual discrimination by infants aged 1, 3, and 5 months of their mother's and a female stranger's face was investigated in visual-only and visual-plus-speech conditions. In the first experiment these infants' discrimination of mother's and female stranger's faces was measured by their visual-fixation-preference scores. Discrimination was found to be facilitated by the addition of speech information. In experiment 2 naive adults viewed silent videotapes of infants from experiment 1 and judged whether the mother had been presented on the infants' left or right. This added further information to the fixation-preference results of experiment 1: it was found that 1-month-olds discriminate mother's and stranger's face only in the presence of speech information, whereas 3-month-olds also do so in visual-only conditions. In experiments 3 and 4 the relative salience of lip movements and voice information in visual recognition of mother's face was investigated. In experiment 3, no significant differences in infants' visual-fixation-preference scores were obtained. However, in experiment 4 adults' 'where is mother?' judgments of video-tapes from experiment 3 were found to be more accurate in the voice than in the lip-movements conditions, especially for the 3-month-olds and more accurate when mother rather than stranger was talking. It is concluded that young infants' visual recognition of mother is facilitated by addition of speech information, that it is primarily the voice component of speech that causes this facilitation, and that social discrimination is best indexed by a dependent variable which is sensitive to a range of facial cues provided by infants.

Acoustic Stimulation↗
PubMed1992

Isoleucine requirements of the chicken: requirement for maintenance.

1. The maintenance requirement of adult male cockerels for isoleucine was measured by nitrogen balance. Measured amounts of a diet first-limiting in isoleucine were fed by tube each day for 6 d to give a range of intakes of from 0 to 100 mg isoleucine/kg body weight. A nitrogen-free diet containing energy, vitamins and both major and trace minerals was offered ad libitum during that time. Two series of diets were used, an unbalanced series, as described above, and a balanced series, in which synthetic L-isoleucine was added to each diet in the unbalanced series. Excreta were collected in bags during the last 3 d of the balance period and the N content of the excreta was analysed on wet, homogenised samples. 2. The resultant linear regressions were not statistically different for the unbalanced and the balanced series indicating that the response measured was to isoleucine. The pooled regression equation was: N retention = -144.14 (+/- 8.5) + 2.421 (+/- 0.19)I where I is the intake of isoleucine in mg/kg body weight day. The isoleucine required to maintain the body at zero N retention was therefore calculated to be 60 (+/- 3.2) mg/kg body weight day. 3. A case has been made for the expression of the amino acids required for maintenance to be in terms not of body weight but scaled according to the degree of maturity of the animal, and on this basis the amount of isoleucine required for maintenance was calculated to be 300 mg per unit of maintenance protein (Pm 0.73 mu) per day.

Amino Acids↗
PubMed1992

Isoleucine requirements of the chicken: the effect of excess leucine and valine on the response to isoleucine.

1. Three experiments were designed to determine the response of broiler chickens to dietary isoleucine, and to quantify the antagonistic effects of excess leucine and valine on this response. 2. A dilution technique was used to measure the responses in growth rate and food intake to a range of diets differing in their isoleucine concentrations. A summit diet was formulated to contain isoleucine at 1.14 times the requirement and with leucine (1.76 times the requirement) and valine (1.87 times the requirement) at the minimum possible concentrations, given the ingredients available. A dilution mixture, devoid of protein, was formulated to correspond in all respects, other than in amino acid content, to the summit diet. These two basal diets were blended in different proportions to give a range of diets of decreasing isoleucine and protein content. 3. In experiment 1 the response was measured to isoleucine with leucine and valine remaining in the same proportion to isoleucine throughout the range of diets fed. In experiments 2 and 3, however, L-leucine and L-valine were added to the diets either singly or in combination to give 6 isoleucine concentrations and 3 ratios of each of leucine and valine to isoleucine. 4. Weight gain decreased as the isoleucine content of the diet was reduced, whereas food intake of broilers fed on the marginally deficient diets increased to a maximum and then decreased. FCE decreased curvilinearly as the isoleucine concentration in the food decreased, reflecting a concomitant change in the fat content of the broilers. 5. It is possible that the amount of dietary isoleucine assumed to be available to the broilers in these experiments was overestimated by hydrolysing the food samples for 72 h, and the doubt thus created makes an estimate of the efficiency of retention of isoleucine suspect. 6. Excess valine had no effect on the response to isoleucine, whereas an increase in the leucine to isoleucine ratio depressed food intake and hence weight gain, but only at the lowest concentrations of isoleucine. 7. If the food content of isoleucine is sufficient to meet the requirements of the broiler, relatively large excesses of leucine, of valine, or of both will not depress growth.

Animal Feed↗
PubMed1991

Visual processing of stimulus compounds in newborn infants.

An experiment is described in which newborn infants' processing of stimulus compounds was investigated. After familiarization to two alternately presented stimuli which differed in colour and orientation, the newborns showed significant preferences for a stimulus which had a novel colour/orientation combination: the novel stimulus was produced by recombining features of the stimuli used for familiarization. This finding argues against the view that infants initially process separate components, or parts, of visual stimuli and are only able to attend to the correlations between them after about 3 months of age. Rather, the ability to process and remember stimulus compounds is present at birth.

Attention↗
PubMed1991

Effects of low-dose cimetidine on nocturnal acid secretion in healthy subjects.

The effects of 100 mg and 200 mg bedtime doses of cimetidine on nocturnal gastric acid secretion were examined in nine healthy subjects in a double blind, placebo controlled, randomised three way crossover study. Treatment was given at 23.00 hours and the gastric contents continually aspirated from midnight until 07.00 hours the following morning. Hourly aliquots were analysed for pH and acid output. Relative to placebo the 100 mg and 200 mg doses of cimetidine respectively increased mean pH by 2.22 and 2.63 units/h (P less than 0.001) with mean acid output decreasing by 0.95 and 0.98 mmol/h (P less than 0.001). Whilst mean pH was higher and mean acid output was lower for 200 mg cimetidine compared to 100 mg cimetidine the difference was not statistically significant. Mean hourly pH was consistently above pH 3 for 100% of the time for both doses of cimetidine whereas mean pH failed to reach this value at anytime on placebo. Low doses of cimetidine taken at bedtime effectively reduced nocturnal gastric acid secretion in healthy individuals.

Administration, Oral↗
PubMed1986

The effects of calcium hydroxide on dentin permeability.

Calcium hydroxide paste was applied to human dentin in vitro to determine its effects on dentin permeability. Discs of dentin were acid-etched on both sides to permit determination of their maximum permeability. Smear layers were then applied to the enamel sides of the discs, thereby reducing dentin permeability 99%. Topical application of Ca(OH)2 paste to the smear layer reduced dentin permeability further, to levels 48% below that of untreated smear layers. When the Ca(OH)2-treated smear layers were exposed to 6% citric acid for two min, dentin permeability returned to the initial acid-etched value, demonstrating that Ca(OH)2 offers little protection to acid challenge. Treatment of acid-etched dentin with Ca(OH)2 produced a similar reduction in dentin permeability, which was restored to normal following acid challenge. Thus, Ca(OH)2 is effective at reducing the permeability of both the smear layer and of acid-etched dentin, in vitro.

Acid Etching, Dental↗