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Biomedical subjects

D Berry

Publications and source records attributed to D Berry.

At least 91 records · Page 5Linked to original sources
PubMed1986

Pharmacodynamics and side effects of flecainide acetate.

We compared side effects with flecainide trough levels and ECG intervals among 43 patients who received flecainide for up to 34 months. Flecainide plasma levels were higher when associated with cardiovascular side effects (mean 1063 ng/ml; range 296 to 2050 ng/ml) than when no side effects occurred (mean 609 ng/ml; range 89 to 1508 ng/ml; P less than 0.001). The PR interval (P less than 0.001), QRS interval (P less than 0.001), and the rate-corrected QT interval (P less than 0.001) were greater at the time of cardiovascular side effects, but the rate-corrected JT interval was not. The therapeutic-toxic window for flecainide plasma level was 381 ng/ml (at least 50% probability of efficacy) to 710 ng/ml (less than 10% probability of cardiovascular side effects). The risk of cardiovascular side effects increases at higher plasma levels of flecainide and is associated with greater increases in the PR and QRS intervals from baseline than are routinely observed during flecainide dosing.

Aged↗
PubMed1986

Thymus deficiency in an infant with a chromosome t(18;22)(q12.2;p11.2)pat rearrangement.

The finding of an unbalanced t(18;22)pat chromosome rearrangement in a boy with multiple anomalies including apparent absence of the thymus is described. The observation is of interest because of the reported association of chromosome 22 rearrangements with the DiGeorge sequence. In contrast to previous reports of this association, the deletion involving chromosome 22 is confined to the short arm.

Abnormalities, Multiple↗
PubMed1986

IS222, a new insertion element associated with the genome of Pseudomonas aeruginosa.

A new insertion element, IS222, was identified to be associated with the DNA of a mutant strain of the converting Pseudomonas aeruginosa bacteriophage D3. The insertion sequence was 1,350 base pairs in size and possessed terminal inverted repeats. The nucleotide sequence contained single cleavage sites for EcoRI and PvuI but none for BamHI, PstI, HindIII, SmaI, or SalI. By Southern hybridization analysis, no homology was found with genomic DNA from P. aeruginosa PAT or Escherichia coli. Genomic DNA from the phage host, P. aeruginosa PAO, contained two sequences homologous to IS222.

DNA Restriction Enzymes↗
PubMed1986

Effect of lipopolysaccharide mutations and temperature on plasmid transformation efficiency in Pseudomonas aeruginosa.

We have isolated, and characterized electrophoretically, two new lipopolysaccharide-defective (rough) mutants of Pseudomonas aeruginosa strain PAO. These strains, AK1401 and AK1414, together with two previously characterized isolates, AK1012 and AK1282, were used as recipients in transformation experiments with plasmid pR01614 DNA. The roughest mutant, AK1282, was not transformable, while the transformation efficiency of AK1012, and to a lesser extent the wild-type strain, was dependent upon the growth temperature. The two new isolates which are less rough than AK1012 were transformed at a frequency equivalent to that of the wild type-strain.

Electrophoresis, Polyacrylamide Gel↗
PubMed1986

Respiratory distress and surfactant inhibition following vagotomy in rabbits.

We used the model of bilateral cervical vagotomy of adult rabbits to cause respiratory failure characterized by pulmonary edema, decreased lung compliance, and atelectasis. We documented an 18-fold increase in radiolabeled albumin leak from the vascular space into alveolar washes of vagotomy vs. sham-operated rabbits (P less than 0.01). Despite a twofold increase in percent of prelabeled saturated phosphatidylcholine secreted (P less than 0.01), the alveolar wash saturated phosphatidylcholine pool sizes were not different. The minimum surface tensions were 19.6 +/- 2.5 vs. 9.4 +/- 2.2 dyn/cm for alveolar washes from vagotomy and control rabbits, respectively (P less than 0.01). The soluble proteins from alveolar washes inhibited the surface tension lowering properties of natural surfactant, whereas those from the control rabbits did not (P less than 0.01). When vagotomy rabbits in respiratory failure were treated with 50 mg natural surfactant lipid per kilogram arterial blood gas values and compliances improved relative to control rabbits. Vagotomy results in alveolar pulmonary edema, and surfactant dysfunction despite normal surfactant pool sizes and respiratory failure. A surfactant treatment can improve the respiratory failure.

Animals↗
PubMed1986

Hemodynamic effects of high frequency ventilation in surfactant-treated preterm lambs.

We compared the hemodynamic status and left ventricular (LV) performance in 7 twin pairs of preterm lambs delivered at 124 days gestational age (83% of term gestation) and ventilated by either conventional ventilation (CV) or high frequency ventilation (HFV) at 15 Hz. The lambs were treated with suspensions of natural sheep surfactant to permit ventilation and survival, and ventilatory settings were adjusted to maintain physiologic blood gas values. The ductus arteriosus was occluded with a balloon catheter at 40-45 min of age to eliminate the variable of a left to right ductal shunt. Cineangiocardiographic, pressure, and blood flow measurements were made 1 and 2 h after ductal occlusion. At the same mean airway pressures, the heart rates, LV end-diastolic volumes, and mean arterial pressures were similar in both groups. LV stroke volumes, ejection fractions, LV outputs, and organ blood flows also did not differ between the two groups. When compared with CV, HFV provides comparable ventilation with no apparent deleterious hemodynamic effects in preterm surfactant-treated lambs with occluded ductus arteriosus.

Acid-Base Equilibrium↗
PubMed1986

A protein that inhibits surfactant in respiratory distress syndrome.

A protein that interferes with surfactant function is present in the airways and alveoli of infants with respiratory distress syndrome (RDS). This inhibitor is also found in serum and amniotic fluid and presumably appears in the alveoli because of the abnormal protein leak present in the lungs of infants with RDS. This protein has a molecular weight of about 110,000 and is resistant to boiling or lipid extraction. As measured by radioimmunoassay, the ratio of inhibitor to phosphatidylcholine decreased from 8.1 +/- 2.3 early in the course of RDS to 0.7 +/- 0.1 on the day of extubation. The value at extubation was the same as that measured for preterm infants without RDS. The inhibitor to phosphatidylcholine ratio in airway samples from infants with RDS correlated significantly with simultaneously recorded pO2/FiO2 ratios and the peak inspiratory pressures used to normalized pCO2 values. These results are consistent with the concept that the inhibitor contributes to surfactant dysfunction and thus the respiratory failure characteristic of RDS.

Amniotic Fluid↗
PubMed1986

Clearance of natural surfactant phosphatidylcholine from 3-day-old rabbit lungs: effects of dose and species.

Surfactants were labeled in vivo with [3H] choline and the large aggregates of the surfactant were recovered by alveolar wash and centrifugation. The labeled natural surfactants from rabbit, sheep, cat, and pig were injected into the airways of 3-day-old rabbits, and the percent recoveries of the labeled surfactant-associated phosphatidylcholine were measured in alveolar washes, lung tissue after alveolar wash, and in the lungs (alveolar wash plus lung tissue). The rabbit surfactant-associated phosphatidylcholine was cleared from the lungs at a constant 15.6 +/- 1.8% per 24 h (mean +/- SE) of the injected doses of surfactant that contained from 0.41 to 10.2 mumol phosphatidylcholine. At all times following injection, approximately 50% of the labeled phosphatidylcholine remaining within the lungs was recovered in the alveolar wash and 50% with the lung tissue. The percent clearances for sheep, cat, and pig surfactant phosphatidylcholine in rabbits were 12.5, 16.6, and 16.3% per 24 h, respectively, values not different from that measured for rabbit surfactant. The results documented a slow clearance of exogenously administered surfactant phosphatidylcholine as a fixed percent of the injected dose that was unchanged by species source of the surfactant.

Animals↗
PubMed1985

Leakage of protein in the immature rabbit lung; effect of surfactant replacement.

Immature newborn rabbits, delivered on day 27 of gestation, were ventilated artificially for 60 min, with or without previous treatment with natural surfactant. Insufflation pressure was adjusted to maintain an average tidal volume of about 10 ml/kg. All animals received, before the onset of ventilation, 125I-labeled albumin via the airways and 131I-labeled albumin intravenously. At the end of the experiment 3.1 +/- 1.3% (means +/- SD) of the 131I-albumin had permeated into the alveolar compartment of control animals; the corresponding figures for surfactant-treated animals were 1.7 +/- 0.8% (P less than 0.002). In control animals only 18.2 +/- 4.4% of the 125I-albumin could be recovered from the airspaces after 60 min, whereas 69.9 +/- 14.6% of this label was recovered in surfactant-treated animals (P less than 0.002). Alveolar wash samples from control animals also contained significantly increased activity of surfactant inhibitor, as evaluated with pulsating bubble. The bidirectional flux of protein, including surfactant inhibitor, was thus significantly decreased in these immature lungs by surfactant replacement.

Albumins↗
PubMed1985

Lung protein leaks in ventilated lambs: effects of gestational age.

To study the protein permeability properties of the ventilated premature lung, we delivered groups of eight lambs at 122 and 135 days gestational age and ventilated the lambs equivalently. The lambs at 122 days gestational age had been treated with natural sheep surfactant at birth, and both groups of lambs had similar pH and blood gas values to 3 h of age. Three groups of lambs at 146 days gestational age also were studied for comparison; four lambs were ventilated to normalized PCO2 values, four lambs were ventilated equivalently to the premature lambs with supplemental CO2 used to normalize PCO2 values, and four lambs were treated with natural surfactant and ventilated similarly to the preterm lambs. The percent recovery into an alveolar wash and lung tissue of 131I-albumin given by intravascular injection and of 125I-albumin given into the airways was measured in each animal after killing at 3 h of age. Full-term lambs had a small bidirectional leak of albumin to and from the alveoli and lung tissue. The recovery of intravascular 131I-albumin in the alveolar wash was 5.8- and 4.1-fold higher in lambs at 122 and 135 days gestational age, respectively, than in full-term lambs. The loss of 125I-albumin from the airways and alveoli also increased as gestational age decreased. The bidirectional flux of albumin to and from the alveoli increased as gestational age decreased in the prematurely delivered and ventilated lambs.

Albumins↗
PubMed1985

Distribution of pulmonary blood flow in relation to atelectasis in premature ventilated lambs.

To investigate the ability of the preterm, ventilated lung to redirect blood flow away from atelectatic regions, we studied lambs with respiratory distress syndrome and spontaneous atelectasis or atelectasis caused by bronchial obstruction with a balloon catheter. Pulmonary blood flow distributions were measured by quantifying 15-mu, microsphere-associated radioactivity within multiple pieces of lung. Lambs with well aerated or very atelectatic lungs had relatively uniform blood flow/gram lung in all pieces of lung. Blood flow was much less uniform in lungs with both aerated and atelectatic regions. In 9 lambs with spontaneous atelectasis that included 25 +/- 5% (mean +/- SE) of the lungs by weight, blood flow was 29 +/- 4% less to atelectatic than to aerated lung volumes (p less than 0.01). In 5 lambs with well-aerated lungs, 18 +/- 3% of the lung by weight was made atelectatic by balloon occlusion of a major lower lobe bronchus. There was a 44 +/- 11% decrease in blood flow to the atelectatic lung segments. These studies document the ability of the lung of the premature, ventilated lamb to shunt pulmonary blood flow away from atelectatic lung volumes.

Animals↗
PubMed1984

Brain syndrome and WAIS PIO VIO difference scores corrected for test artifact.

Found an artifactual discrepancy of six units between VIQ and PIQ in Ss (N = 62) of low and bright, but not of mid-range IQ. Despite the matching of psychiatric cases for dominant and nondominant cognitive function, the discrepancy took the form of a lowered PIQ. The application of an equivalent correction to the PIQs of consecutive and unmatched psychiatric cases failed to improve the neurological predictive utility of the VIQ PIQ difference score. The latter failed statistically as an alerting device for abnormal CT and EEG results and whether a neurological event was recorded in the file. Despite the observation of a strong relationship between CT outcome and VIQ PIQ difference score evidence of cognitive intactness, it was concluded that difference score, whether corrected or not, should be used with extreme caution as a screening device for psychiatric cases who might be harboring an underlying brain syndrome.

Adult↗
PubMed1984

A pharmacokinetic comparison of choline magnesium trisalicylate and soluble aspirin.

Claims that twice-daily dosage of choline magnesium trisalicylate (CMT) may alter salicylate disposal kinetics and result in sustained plasma levels were examined. Plasma levels, urine excretion and pharmacokinetics of salicylate were estimated in six men following the recommended twice-daily dose of CMT and a smaller dose of soluble aspirin. The plasma salicylate levels achieved with CMT were lower than those seen in previous studies but this probably reflected differences of methodology. Salicylate levels were not sustained between doses and elimination rates and half-life were similar for both preparations. No major alteration of disposal kinetics could be demonstrated for CMT with the dose used in the present study.

Administration, Oral↗
PubMed1983

Anaerobic biodegradation of phenolic compounds in digested sludge.

We examined the anaerobic degradation of phenol and the ortho, meta, and para isomers of chlorophenol, methoxyphenol, methylphenol (cresol), and nitrophenol in anaerobic sewage sludge diluted to 10% in a mineral salts medium. Of the 12 monosubstituted phenols studied, only p-chlorophenol and o-cresol were not significantly degraded during an 8-week incubation period. The phenol compounds degraded and the time required for complete substrate disappearance (in weeks) were: phenol (2), o-chlorophenol (3), m-chlorophenol (7), o-methoxyphenol (2), m- and p-methoxyphenol (1), m-cresol (7), p-cresol (3), and o-, m-, and p-nitrophenol (1). Complete mineralization of phenol, o-chlorophenol, m-cresol, p-cresol, o-nitrophenol, p-nitrophenol, and o-, m-, and p-methoxyphenol was observed. In general, the presence of Cl and NO2 groups on phenols inhibited methane production. Elimination or transformation of these substituents was accompanied by increased methane production, o-Chlorophenol was metabolized to phenol, which indicated that dechlorination was the initial degradation step. The methoxyphenols were transformed to the corresponding dihydroxybenzene compounds, which were subsequently mineralized.

Anaerobiosis↗
PubMed1983

Therapeutic, toxic and fatal blood concentration ranges of antiepileptic drugs as an aid to the interpretation of analytical data.

1 Problems associated with the interpretation of analytical results are often related to the ineffective presentation of reference information. Concentration-response curves overcome many of the problems by presenting all available information concisely and by allowing clear comparisons between drug concentrations associated with different pharmacological responses. Although visual comparison of such curves is possible, it can be advantageous to represent them numerically. 2 Numerical representations are used in the present work to compare sub-therapeutic, optimally therapeutic, toxic (side-effects and severe effects), and fatal blood concentrations of the commonly prescribed antiepileptic drugs. 3 Blood drug concentrations accounting for 50% of the population (EC50) are expressed in relation to the concentrations accounting for 10% (EC10) and 90% (EC90) of the population in each clinical category. 4 Such EC10-EC50-EC90 ranges are shown to represent adequately the concentration-response curves. They demonstrate the overlap between drug blood concentrations associated with the various responses and give a good indication of the expected response at any concentration. The concentration ranges are therefore a very useful interpretative aid in therapeutic drug monitoring, emergency toxicology, and forensic toxicology.

Anticonvulsants↗