Simple cultural tests for identification of Agrobacterium biovars.
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Bacterial Typing Techniques↗
Biomedical subjects
A L Bishop
Publications and source records attributed to A L Bishop.
Albuterol aerosol versus albuterol Rotacaps in exercise-induced bronchospasm in children.
The purpose of this study was to determine the safety and effectiveness of albuterol aerosol 180 micrograms and albuterol powder 200 micrograms in the prevention of exercise-induced bronchospasm in children. Forty-six patients aged 4-11 years with asthma and exercise-induced bronchospasm were enrolled in this randomized, double-blind, single-dose, three-way crossover study comparing albuterol aerosol, albuterol powder, and placebo. Exercise challenge was performed at the screening visit for qualifying and baseline determinations of pulmonary function and then 15 min after drug administration at each of three visits. Prevention of exercise-induced bronchospasm was assessed by comparing across all treatment groups the percentage change in FEV1 from pre- to postexercise, the percentage of patients protected by treatment, postexercise minimum FEV1, and postexercise change in FEV1. Safety was assessed by observation of clinical adverse events, laboratory tests, physical examination, electrocardiogram and rhythm strips, vital signs, and pulmonary auscultation. Forty-four patients completed the study. Mean postexercise FEV1 decreased 6% from preexercise values when patients were treated with either albuterol formulation; FEV1 decreased 23% when patients were treated with placebo. Exercise-induced bronchospasm was prevented in 95% of patients when treated with albuterol powder, in 91% treated with albuterol aerosol, and in 57% treated with placebo. Patients maintained significantly higher mean minimum FEV1 values after treatment with albuterol powder and albuterol aerosol than when treated with placebo. Treatment with either albuterol formulation produced a significantly smaller decrease in mean FEV1 from pre- to postexercise than treatment with placebo. No drug-related adverse events were reported, and safety assessments were within normal limits.(ABSTRACT TRUNCATED AT 250 WORDS)
Administration, Inhalation↗
Efferent terminals in the cochlea of the mustached bat: quantitative data.
Efferent terminals in the cochlea of the mustached bat were stained for acetylcholinesterase (AChE) and quantitative data were obtained for the number and size of the endings on the outer hair cells (OHCs) in each row, from base to apex. From TEM micrographs and AChE-stained, surface preparations it was determined that every OHC had a single, large terminal. The mean size of the terminals was significantly different in each row, with the largest occurring in the first row (7.1 microns 2); the mean size in the second and third rows was 5.7 and 5.0 microns 2 respectively. In specific frequency processing regions, the largest mean size (8.4 microns 2) for first row OHCs was consistently found in the distal densely innervated (DDI) area. This region has afferent neurons that are sharply tuned to the second harmonic, constant frequency component of the bat's biosonar signals. Sudden changes in the size of the terminals were observed exactly at the boundaries of the DDI with adjacent sparsely innervated regions. Similar, but less striking, size changes also occurred in and adjacent to the proximal densely innervated (PDI) region, a harmonically related, sharply tuned region, which processes the bat's 91.5 kHz, third harmonic, constant frequency signals. The region of the cochlea with the smallest first row terminals (mean 5.3 microns 2) was the large, sparsely innervated region of the basal turn, a region that does not appear to process biosonar signals. Although the significance of differences in efferent terminal size is not known, the data suggest a possible correlation between OHC stimulation and sharp tuning. The potentially greater influence of the efferent fibers on the first row of OHCs, compared to other rows, is consistent with observations made on other mammals; in the latter, however, the greater influence has been suggested more by number than size. Unlike other mammals, the OHC efferents in the mustached bat have no clear base-to-apex gradient in the number or size of the efferent terminals. It is suggested that this might reflect the high frequency nature of the ear (6-120 kHz) and absence of low frequency hearing.
Acetylcholinesterase↗
Twenty-four-hour intragastric pH patterns in ICU patients on ranitidine.
Thirty critically ill patients with mixed diagnoses underwent continuous intragastric pH monitoring for 72 hr while confined to a shock/trauma intensive care unit. The first 24 hr were monitored under no specific acid-suppressing therapy (placebo control). During the second and third consecutive 24-hr periods, patients received continuous infusion of intravenous ranitidine in the dose of 6.25 mg/hr and 12.5 mg/hr, respectively. Results of the placebo-control 24-hr study revealed that one third (N = 10) of the patients were gastric acid hyposecretors (24-hr median intragastric pH values above pH 4.0). In the normosecreting group (N = 20), both ranitidine schedules significantly elevated 24-hr median pH values, when compared to placebo (placebo 24-hr median intragastric pH 1.75; ranitidine 6.25 mg/hr 24-hr median intragastric pH 4.625, P < 0.0001; ranitidine 12.5 mg/hr 24-hr median intragastric pH 6.29, P = 0.0099). Five patients (18%) failed to adequately respond to the ranitidine 12.5 mg/hr dose (24-hr median intragastric pH < 4.0). These findings suggest that a significant percentage of intensive care unit patients are not in need of acid-suppressing therapy as prophylaxis against stress-induced ulceration. Conversely, other patients may require more intensive acid-suppressing regimens because of failure to respond to high dose H2-antagonist therapy.
Adolescent↗
Pharmacokinetics and pharmacodynamics of ranitidine after burn injury.
The pharmacokinetics and pharmacodynamics of ranitidine were studied in 10 hypermetabolic burned patients with normal creatinine clearance and compared with healthy volunteers. Ranitidine was administered as a single 50 mg intravenous bolus and multiple blood samples were obtained up to 10 hours after the dose for determination of plasma ranitidine concentrations. Gastric pH in burned patients was monitored by way of a nasogastric tube. Burned patients exhibited significantly higher (p less than 0.01) ranitidine clearance (mean +/- SD; 10.80 +/- 2.38 versus 7.53 +/- 1.71 ml/min/kg) and steady-state distribution volume (1.63 +/- 0.13 versus 1.16 +/- 0.33 L/kg). Within an hour of administration of drug the gastric pH was greater than or equal to 4.0 in all but one patient. This pH was maintained for at least 6 hours. In five patients the pH was greater than or equal to 4.0 throughout the 10-hour study. Thus, despite increased ranitidine clearance, the recommended dose of ranitidine maintained gastric pH greater than or equal to 4.0 throughout the normal dosing interval in the majority of patients. Dosage adjustment reported for many other drugs after burn injury may not be necessary for ranitidine.
Adult↗
Intragastric pH and pharmacokinetics of intravenous ranitidine during sinusoidal and constant-rate infusions.
Six patients with healed duodenal ulcer completed two treatment periods with continuous i.v. infusion ranitidine. A 25-mg i.v. bolus was followed by a constant infusion at 6.25 mg/h or a sinusoidal infusion with infusion rates ranging from 3.125 to 9.375 mg/h. The sinusoidal infusion rate was designed to match the previously observed circadian changes in basal acid secretion. The peak infusion rate occurred at 19:30 h. A pharmacokinetic method was designed to predict the resultant plasma concentrations of ranitidine. Intragastric pH and plasma ranitidine concentration data were fit to a cosine function to evaluate circadian and ultradian rhythms. Plasma concentrations during the sinusoidal infusion exhibited a circadian rhythm according to model predictions. Cosinor analyses of the mean ranitidine plasma concentration data showed a mesor concentration of 237 ng/mL and amplitude of 76 ng/mL (coefficient of determination [CD] = 0.98). The acrophase in plasma concentration occurred at 2223 h, a delay of approximately 2.9 hours from the peak in the infusion rate. The constant-rate infusion resulted in a mean plasma concentration of 222 +/- 32 ng/mL. The 24-h mean intragastric pH values for the sinusoidal and constant regimens were 5.4 and 5.1, respectively (p = 0.170). The intragastric pH during the constant-rate infusion exhibited a significant circadian rhythm (CD = 0.52). The minimum pH (bathy-phase) occurred at 2031 h. No circadian rhythm was present during the sinusoidal-rate infusion (CD = 0.08). At the approximate time of the peak basal acid secretion, between 21:00 hours and midnight, the mean pH for the sinusoidal infusion was 5.77 versus 4.5 for the constant-rate infusion (p = 0.112). Sinusoidal infusions or alternate methods of increased doses at the times of peak acid output may improve around-the-clock control of intragastric pH.
Adult↗
Pharmacodynamics of intravenous ranitidine after bolus and continuous infusion in patients with healed duodenal ulcers.
Fifteen adult men who had histories of duodenal ulcer disease were studied for 24 hours during treatment with varying intravenous doses of ranitidine (50 mg every 8 hours, 100 mg every 12 hours, 6.25 mg/hr continuous infusion, and 10 mg/hr continuous infusion) and placebo. Gastric pH was monitored under fasting conditions by means of an indwelling pH sensitive electrode. The continuous infusion regimens provided the most constant level of acid suppression. A "breakthrough" decrease in gastric pH began at approximately 6 PM at the 6.25 mg/hr dose level. The drop in pH at the 10 mg/hr dose level was less impressive. Ranitidine, 100 mg every 12 hours, resulted in better acid suppression than the regimen of 50 mg every 8 hours. A gastric pH greater than or equal to 4 was achieved 35 to 50 minutes after the start of administration for all regimens. The median effective concentration (EC50) of ranitidine was approximately 45 ng/ml. Continuous infusion regimens, with a dosage adjustment for the time of day, may be the optimal dosage regimen for patients requiring continuous protection from gastric damage by hydrochloric acid. Bolus loading doses are not required to speed the onset of effect in the clinical setting.
Adult↗
The efferent cochlear projections of the superior olivary complex in the mustached bat.
Following the placement of horseradish peroxidase in the scala tympani, labeled neurons were found in the ipsilateral interstitial nucleus (INT) and throughout the ipsilateral and contralateral dorsomedial periolivary nuclei (DMPO). The neurons in the INT were morphologically distinct from those in the DMPO. The INT neurons formed a thin shell over the lateral superior olivary nucleus (LSO) and their dendrites extended into the body and hilar region. The DMPO neurons had long, tapering dendrites that extended in every direction. Data indicate that the crossed fibers in the floor of the ventricle arise entirely from the DMPO while uncrossed olivocochlear fibers originate in the INT and DMPO. It was estimated that 75% of the efferent fibers arise from the INT and 25% from the DMPO. Approximately 70% of the efferent neurons in each DMPO project to the contralateral cochlea via the crossed olivocochlear bundle. The number of olivocochlear neurons associated with each ear was determined to be approximately 1585. This number is similar to that found in cats and guinea pigs, but the number of neurons per unit length of the basilar membrane is considerably higher in the mustached bat than in other species examined to date. The compact, restricted locations of the neurons in the INT and DMPO in the mustached bat are different from those described for most other mammals and the arrangement in the mustached bat offers advantages over other species for future anatomical and physiological studies.
Animals↗
Echo intensity compensation by echolocating bats.
When mounted on a swinging pendulum, mustache bats, Pteronotus p. parnellii, emit ultrasonic pulses as they move toward and away from fixed targets. During forward swings they systematically decrease the intensity of their emitted pulses and during backward swings they increase the intensity. In this way, echo strength is continuously adjusted and apparently optimized for signal analysis. We have called this behavior echo intensity compensation. Pteronotus simultaneously Doppler and echo intensity compensate during forward swings of the pendulum but during backward swings they only echo intensity compensate. Pteronotus can regulate the intensity of both the constant frequency and frequency modulated components of their pulses; this regulation is independent of vestibular cues, pulse repetition rates, pulse durations and pulse-echo intervals.
Animals↗
Short- and long-term retention of a nursing home education program on metered-dose inhaler technique.
OBJECTIVE: To evaluate an education program on metered-dose inhaler (MDI) technique designed for nurses and trained medication aides (TMAs). DESIGN: The education program included a handout, a lecture incorporating a videotape on correct inhaler and device technique, and hands-on experience with placebo inhalers. The participants' ability to verbalize and demonstrate correct MDI technique was assessed by the same two-person teams before, immediately after, and two months after the program. SETTING: Five nursing homes. PARTICIPANTS: Fifty-six nurses and TMAs practicing in nursing homes. MAIN OUTCOME MEASURES: Learning and retention. RESULTS: The participants' mean (+/- SD) verbal and demonstration scores increased immediately after the program by 68 +/- 18 points for verbalization and 47 +/- 16 points for demonstration. The participants were always better at demonstrating than verbalizing MDI technique. The participants' baseline verbal and demonstration scores correlated with the amount learned. Learning was influenced by the individual nursing home (verbal and demonstration) and personal use (demonstration only), but not by academic degree, previous training, past instruction of a patient, or current care of a patient who was receiving inhaler therapy. After two months, the scores were lower than immediately after the program test by 0-92 points for verbalization and 10-80 points for demonstration; however, the mean scores were still significantly greater (p less than 0.05) than the baseline scores. Retention of knowledge on the correct technique was greater for the demonstration component. Retention was influenced only by the nursing home in which the participant worked, and not any of the other variables. CONCLUSIONS: Our structured education program significantly improved inhaler technique; however, to maintain retention of the material, the program should be frequently repeated.
Clinical Competence↗