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Biomedical subjects

J A Buckley

Publications and source records attributed to J A Buckley.

At least 37 records · Page 2Linked to original sources
PubMed1984

Efficacy of epinephrine concentration in local anesthesia during periodontal surgery.

Blood loss in periodontal flap surgery using lidocaine 2% with either 1:50,000 or 1:100,000 epinephrine was compared. Ten patients from the graduate periodontal clinic were selected for the study. After the initial therapy which included oral hygiene instruction, scaling and root planning and occlusal adjustment, 20 surgical procedures were performed. In any one patient if 1:50,000 epinephrine was used on the posterior sextant of an arch, then 1:100,000 epinephrine was used on the contralateral side, with similar volumes being injected by the same method. Blood loss was determined by the cyanmethemoglobin comparison technique. Procedures using lidocaine 2% with 1:100,000 epinephrine generally had more than twice as much blood loss as those using lidocaine 2% with 1:50,000 epinephrine.

Anesthesia, Dental↗
PubMed1983

Pharmacokinetics of intravenously administered piperacillin in preadolescent children.

We studied the pharmacokinetics of piperacillin in 37 preadolescent children (mean age 52 months, range 1 month to 11 years) after 50 mg/kg IV doses. Pharmacokinetic parameters were determined after the initial dose in 18 instances and after subsequent doses in 32 instances. There were no significant differences between the initial doses and the subsequent doses in the plasma piperacillin concentrations at comparable times, the elimination rate constants, the elimination-phase plasma half-lives, the total body clearances, the apparent volumes of distribution, or the areas under the concentration curves. At the end of a 30-minute infusion of the drug, the plasma concentration was 166.2 +/- 42.2 mg/L (mean +/- SD) and ranged from 91.6 to 268.3 mg/L. The mean half-life was 31.0 +/- 9.4 minutes. The half-life of piperacillin in children 1 to 6 months of age (47.2 minutes) was significantly longer than in older children (28.8 minutes) (P less than 0.05). Likewise, the total body clearance of the drug in the younger age group (71.7 ml/min/m2) was significantly lower than in the older children (130.8 ml/min/m2) (P less than 0.05). The mean renal clearance of the drug was only 63% (range 39% to 85%) of the total body clearance, suggesting a variable but substantial nonrenal route of elimination. The intravenous administration of 50 mg/kg piperacillin every four hours results in adequate plasma concentrations for the treatment of most infections caused by gram-negative and gram-positive organisms.

Bacterial Infections↗
PubMed1982

Immunosuppression by fractionated total lymphoid irradiation in collagen arthritis.

Treatments with fractionated total lymphoid irradiation (TLI) and cyclophosphamide were evaluated for rats injected with type II collagen. Preadministration of TLI and repeated injections of cyclophosphamide suppressed the severity of arthritis and lowered antibody titers to collagen significantly. TLI initiated at the onset of collagen arthritis decreased humoral and cellular responses to collagen but did not affect the severity of arthritis. These data demonstrate that both TLi and cyclophosphamide are immunosuppressive in an experimentally inducible autoimmune disease.

Animals↗
PubMed1982

Pharmacokinetics of intramuscular ceforanide in infants, children, and adolescents.

We studied the pharmacokinetics of intramuscular ceforanide in 46 infants, children, and adolescents, ranging in age from 1 month to 17 years. After the subjects were given 20-mg doses of ceforanide per kg, the mean peak plasma concentration was 56.3 microgram/ml (range, 27.0 to 95.0), the mean 8-h level was 5.9 microgram/ml (range, 1.5 to 13.5), and the mean 12-h level was 1.5 microgram/ml (range, 0.2 to 4.2). Ceforanide half-life varied with the ages of the patients: in 1- to 2-year-old children, in half-life was significantly shorter (1.5 h) than in younger or older children. Plasma concentrations at 8 and 12 h after a dose were lowest in 1- to 2-year-old children. There was no relationship between the area under the curve, the volume of distribution, or the body clearance of ceforanide to the ages of the patients. Within 6 h of administration of the drug, a mean of 77.5% of a dose was excreted in urine, and at the end of 12 h, virtually all (93.9%) of the administered dose was recovered in urine samples. The administration of ceforanide every 12 h did not result in drug accumulation. A dose of 20 mg of ceforanide per kg every 12 h is recommended for most pediatric patients. Dosage recommendations for 1- to 2 year-old children are presented.

Adolescent↗
PubMed1981

Clinical and immunologic effects of fractionated total lymphoid irradiation in refractory rheumatoid arthritis.

Ten patients with refractory rheumatoid arthritis were given 3000 rad of fractionated total lymphoid irradiation in an uncontrolled therapeutic trial. Total lymphoid irradiation was associated with objective evidence of considerable clinical improvement in eight patients and with reduced blood lymphocyte counts in all 10. On completion of irradiation, there was an abrogation of lymphocyte reactivity in vitro in the patients with clinical responses, but abnormal antibody activities characteristic of rheumatoid arthritis and normal components of humoral immunity were not suppressed. Partial recrudescence of arthritis occurred shortly after a year after the completion of irradiation and was paralleled by a restitution of lymphocyte concentrations and responsiveness to mitogens to levels similar to those observed before irradiation. These data provide further evidence of T-cell involvement in the pathogenesis of rheumatoid arthritis and demonstrate that total lymphoid irradiation can induce temporary relief, but they do not ascertain whether the natural history of this disease was altered.

Aged↗
PubMed1981

Relative bioavailability of intravenous chloramphenicol succinate and oral chloramphenicol palmitate in infants and children.

The relative bioavailability of intravenously administered chloramphenicol succinate and orally administered chloramphenicol palmitate was compared in 18 children, age 2 months to 14 years. The area under the serum concentration vs time curve of chloramphenicol and urinary excretion of chloramphenicol succinate were determined in each child under steady-state conditions while receiving chloramphenicol succinate and again while receiving chloramphenicol palmitate. The mean AUC was significantly greater during oral therapy compared to intravenous therapy (110 vs 78 mg hr/L, P less than 0.001). The relative bioavailability of chloramphenicol succinate was 70% compared to chloramphenicol palmitate. This could be explained by the mean loss of 36% of the intravenous dose in the urine as unhydrolyzed chloramphenicol succinate. The intravenous dose of chloramphenicol succinate did not correlate with AUC (r = 0.193). However, there was a significant correlation between the oral dose of chloramphenicol palmitate and AUC (r = 0.429, P = 0.025). The bioavailability of orally administered chloramphenicol palmitate is superior to that of chloramphenicol succinate given intravenously. Furthermore, there is a greater correlation between dose and amount of active drug in the body when the oral preparation is used. Oral administration of chloramphenicol palmitate appears to offer significant therapeutic advantages in patients who can tolerate medication given orally.

Administration, Oral↗
PubMed1981

Diffusion of moxalactam into the cerebrospinal fluid in children with bacterial meningitis.

We studied the penetration of moxalactam into the cerebrospinal fluid of 16 children (age range one month to 4 1/2 years) who were being treated for bacterial meningitis. Two hours after single intravenous doses of 15 or 25 mg/kg, moxalactam was detectable in the CSF in only one of 11 instances; however, following three doses (50 mg/kg each) moxalactam was detectable in eight of 17 instances. In these eight instances CSF concentrations of moxalactam ranged between 1.5 and 18.9 micrograms/ml (mean 7.7) and the CSF/plasma ratio ranged from 2.6 to 36% (mean 17.7). There was no relation between the stage of meningitis or the CSF cell count and the diffusion of the drug into the CSF. However, the diffusion of the drug significantly correlated with the CSF protein content. In view of the unpredictability of moxalactam penetration into CSF, caution should be exercised in using it alone in the treatment of meningitis.

Anti-Bacterial Agents↗
PubMed1981

Pharmacokinetics of chloramphenicol and chloramphenicol succinate in infants and children.

The metabolism and elimination of chloramphenicol-3-monosuccinate was studied in 45 infants and children, ages 3 days to 16 years, during intravenous administration. The apparent half-life of chloramphenicol was extremely variable, ranging from 1.7 to 12.0 hours with a mean of 5.1 hours. Apparent half-lives were inversely correlated with age. Chloramphenicol-S serum concentration declined biexponentially in most patients, with an estimated mean initial half-life of 0.7 hours and a subsequent longer mean half-life of 2.2 hours. Chloramphenicol-S persisted in serum up to six hours after a dose, and comprised a significantly larger fraction of total chloramphenicol in the serum of infants under one month of age than in older infants and children. A widely variable fraction of the administered chloramphenicol-S dose, with a mean of 33%, was excreted in the urine unchanged and was, therefore, not bioavailable in active form. Mean renal clearance of chloramphenicol-S was 259.5 ml/minute/1.73 M2, four times the mean creatinine clearance, indicating active tubular secretion. Variable hydrolysis and renal elimination of nonhydrolyzed chloramphenicol-S reduces the bioavailability of the antibiotic and appears to contribute substantially to the wide variation in apparent half-life and poor correlation between dose and serum concentration of free chloramphenicol.

Adolescent↗
PubMed1981

Pharmacokinetic and clinical evaluation of moxalactam in infants and children.

37 patients ranging in age from 9 months to 14 years, with various infections, were treated with moxalactam. The pharmacokinetics of the drug were studied in 18 patients. The mean plasma concentration 1 h after a 25 mg/kg intravenous dose was 41.4 micrograms/ml +/- 15.6 SD, the half-life was 1.5 h +/- 0.4 SD and the mean Vd was 550 ml/kg +/- 239 SD. The total body clearance of moxalactam was 4.1 ml/min/kg +/- 1.5 SD and the mean renal clearance 4.5 ml/min/kg +/- 2.8 SD. Between 52 and 107% of the administered dose was recovered in the urine within 8 h after administration. The pharmacokinetics after the first and multiple doses of moxalactam were similar, indicating no accumulation of the drug with repeated administration. The clinical response was adequate in 35 of 37 patients. Moxalactam was well tolerated and only minor and transient hematological abnormalities were observed.

Adolescent↗
PubMed1979

Real-time analysis of breath using an atmospheric pressure ionization mass spectrometer.

A new technique is reported resulting in the direct, instantaneous analyses of trace compounds in breath. The analyses were performed using a commercial atmospheric pressure chemical ionization mass spectrometer (TAGA TM2000 APCI mass spectrometer). A known flow of breath sample is introduced into the ionization region of the mass spectrometer. The study includes the measurement and monitoring in real-time, of breath ammonia during a 24 hour and a 48 hour period. The ammonia profiles indicate a personalized daily pattern associated with each subject. This method appears to be of potential value in routine detection and treatment of hyperammonemia patients. Results also show that it is possible to obtain instantaneous analyses of several naturally occurring metabolites and other substances on breath in the ppm to ppt range, suggesting a number of diagnostic research applications.

Air↗
PubMedDate not supplied

CT features of pulmonary nocardiosis.

OBJECTIVE: Our goal was to identify the CT features of pulmonary nocardiosis, specifically in AIDS patients versus other immunocompromised hosts. MATERIALS AND METHODS: Twenty-four patients with pulmonary nocardiosis were identified; medical records, CT scans, and chest radiographs were reviewed. Five patients had HIV disease, 17 had other causes of immunosuppression, and 2 had normal immunity. RESULTS: CT features of pulmonary nocardiosis included one or more nodules/masses (20/24 cases, 83%), cavitation (8, 33%), consolidation/infiltrates (8, 33%), and pleural thickening (7, 29%). All AIDS patients with nocardiosis had multiple (four or more) nodules detected on CT and 80% (4/5) had cavitation compared with 21% each of non-AIDS patients (p < 0.01 for multiple nodules, p < 0.045 for cavitation). CONCLUSION: CT features of pulmonary nocardiosis are varied, and AIDS patients are more likely to display cavitation and multiple nodules. Although not widely recognized, Nocardia infection should be included in the differential diagnosis of an unexplained nodule or progressive cavitary process in HIV-positive patients.

AIDS-Related Opportunistic Infections↗
PubMedDate not supplied

The accuracy of CT staging of small bowel adenocarcinoma: CT/pathologic correlation.

PURPOSE: Several studies have documented the use of CT in the evaluation of small bowel neoplasms, but few have addressed the CT staging of adenocarcinoma. We retrospectively correlated CT and pathologic staging to evaluate the accuracy of CT for staging small bowel adenocarcinoma using American Joint Committee on Cancer criteria. METHOD: The preoperative CT scans of 15 patients with pathologically proven small bowel adenocarcinoma were analyzed. Two blinded readers separately interpreted extent of invasion, presence of lymphadenopathy, and distant metastases. Pathologic and CT staging were compared. RESULTS: The overall accuracy of CT staging was 47% (14/30). The sensitivity of detection of mesenteric infiltration was 88%. The sensitivity and specificity for detection of distant metastases were 58 and 63% and for lymphadenopathy 75 and 20%, respectively. Errors occurred in patients with Crohn disease, adenomas, Peutz-Jegher syndrome, small bowel obstruction, and perforation and on suboptimal studies. CONCLUSION: The accuracy of CT staging of small bowel adenocarcinoma is 47%. CT is highly sensitive but not specific for the detection of mesenteric infiltration and regional lymphadenopathy. Since spiral CT may offer improved detection of distant metastases and increased accuracy in the evaluation of patients with concomitant bowel disease, further research is needed to determine the maximal utility of CT in the staging of adenocarcinoma of the small bowel.

Adenocarcinoma↗