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Biomedical subjects

C E Johnson

Publications and source records attributed to C E Johnson.

At least 73 records · Page 4Linked to original sources
PubMed1994

Measles vaccine immunogenicity in 6- versus 15-month-old infants born to mothers in the measles vaccine era.

HYPOTHESIS: The low titer of measles antibody in infants of mothers with vaccine-induced immunity may allow immunization against measles before 15 months of age. METHODS: Six- and 15-month-old infants born to mothers < or = 30 years of age with no history of measles were recruited. Infants enrolled at 6 months of age were immunized with monovalent measles vaccine (Attenuvax), and maternal serum and infant pre- and postvaccination sera were obtained. Those enrolled for primary vaccination at 15 months of age received either Attenuvax (N = 12) or M-M-RII (N = 3). Six-month-old infants were revaccinated with M-M-RII at 15 months of age; pre- and postrevaccination sera were again obtained. Three antibody assays were used: a measles neutralizing assay (NT) and two enzyme immunoassays (EIA) for measles IgG and measles IgM. RESULTS: Among primary vaccinees, 14 of 19 infants aged 6 months (74%) developed NT antibody, as did 15 of 15 infants aged 15 months (100%). The reciprocal geometric mean titer of 6-month-old seroresponders was 23.3, significantly lower than that of the 15-month-old primary vaccinees (87.7, P < .001). Primary seroconversion rates by EIA were 53% for 6-month-old infants and 100% for those aged 15 months. Revaccination of infants who had received Attenuvax at 6 months of age resulted in 100% NT positivity; the geometric mean titer rose to equal that of the group given primary immunization at 15 months of age. Measles IgM antibody was detected in 10 of 14 infants tested 1 month after primary vaccination at 15 months, but was not detected in any of the revaccinated infants after the second dose at 15 months of age (P < .001). CONCLUSIONS: 1) Immunization with measles vaccine in infants born to vaccine-immune mothers at 6 months of age induced NT antibody in 74% of infants. 2) Revaccination of prior 6-month-old vaccinees at 15 months resulted in antibody titers equivalent to 15-month-old vaccinees. 3) Lack of an IgM response following revaccination suggests that even seronegative infants may be primed to respond on re-exposure to measles.

Adult↗
PubMed1993

The role of bacterial adhesins in the outcome of childhood urinary tract infections.

OBJECTIVES: To compare the efficacy of 3-day vs 10-day treatment with a combination of amoxicillin and clavulanate potassium for children with uncomplicated urinary tract infections and to determine the role of host factors, including vesicoureteral reflux, and of bacterial virulence factors, including adhesins, in treatment outcome. DESIGN: Randomized, double-blind, controlled trial. SETTING: A pediatric infectious diseases clinic at an urban medical center. PATIENTS: Thirty-seven children with uncomplicated urinary tract infections. INTERVENTIONS: Treatment with 3 days or 10 days of antibiotics at a dosage of 20 mg/kg per day of amoxicillin and 5 mg/kg per day of clavulanate potassium in three divided doses. MEASUREMENTS AND MAIN RESULTS: The success rate for 10-day treatment was 82% (14/17) compared with 55% (11/20) for 3-day treatment (P = .09). Among the 35 patients infected with Escherichia coli, all 10 patients infected with adhesin-negative isolates were treated successfully regardless of the duration of treatment, whereas only 14 (56%) of the 25 infections involving adhesin-positive isolates were clinically cured (P = .015). Two of the three failures in the 10-day treatment group were in patients with reflux. CONCLUSIONS: We conclude that 3-day treatment with amoxicillin and clavulanate is insufficient for afebrile childhood urinary tract infections and that both bacterial and host factors affect treatment outcome.

Adhesins, Escherichia coli↗
PubMed1993

A convincing case for primary repair of penetrating colon injuries.

Over the past 14 years, 146 patients with penetrating colon trauma were managed by primary repair with/without resection (PR, n = 55), and by diverting colostomy (DC, n = 91). These groups did not differ in terms of age, ISS (Injury Severity Scale), PATI (Penetrating Abdominal Trauma Index), a-AIS (abdominal Abbreviated Injury Scale), or preoperative hypotension. No intergroup differences were manifested in intra-abdominal complications (fistula/leak, abscess, pancreatitis, intestinal obstruction, wound dehiscence). The percentage of patients who experienced at least one major intra-abdominal complication did not differ statistically when the two groups were compared--12.7% in PR versus 11% in DC--although risk in both groups increased with the additional number of organs injured. Wound infection was significantly higher (p < 0.05) in the PR group (19.6%) compared with the DC group (9.4%). Mortality in the PR and DC groups was 0% and 3.6%, respectively. One hundred and ten patients who underwent elective colostomy closure following trauma had a 9.1% intra-abdominal complication rate and a 3.6% wound infection rate. These risks should be considered when colostomy is selected to manage patients with penetrating colon injury. These data support primary repair of all colon injuries, reserving skin closure for patients with limited collateral damage.

Adult↗
PubMed1993

Bacterial polysaccharide immune globulin for prophylaxis of acute otitis media in high-risk children.

We evaluated the prevention of recurrences of acute otitis media (AOM) by bacterial polysaccharide immune globulin (BPIG), a hyperimmune human immune globulin prepared by immunizing donors with bacterial polysaccharide vaccines. We used a randomized, stratified, double-blind, placebo-controlled design. Children < or = 24 months of age with 1 to 3 prior episodes of AOM received BPIG, 0.5 ml/kg, or saline placebo intramuscularly at entry and 30 days later. During the 120-day follow-up period, AOM was diagnosed by using clinical criteria and was confirmed with tympanocentesis and culture of the middle ear exudates. Eighty-eight episodes of AOM were observed in 76 patients who completed the study. The incidence of AOM during the entire 120-day study period was similar in BPIG and placebo recipients. Pneumococcal AOM was significantly less frequent in BPIG recipients (0.21 episode per patient) than in placebo recipients (0.45 episode per patient; p = 0.05). Time spent free of AOM was significantly prolonged in recipients of BPIG, in comparison with placebo recipients (51 vs 35 days; p = 0.034). This study demonstrated that circulating antibody, even without stimulation of specific local immunity, may prevent infection of the middle ear. The use of immune globulin preparations for longer periods or at a higher dosage might decrease the incidence of recurrent AOM in otitis-prone children, and deserves further evaluation.

Acute Disease↗
PubMed1993

Stability of an extemporaneously compounded baclofen oral liquid.

The stability of baclofen in an extemporaneously compounded oral liquid formulation for 35 days was studied. A suspension was prepared by grinding commercially available 20-mg baclofen tablets and adding Glycerin, USP, to form a paste. Simple Syrup, NF, was added as necessary to make a final volume of 60 mL. A control solution was prepared from analytical-grade baclofen powder in Simple Syrup, NF. The final concentration of baclofen in both formulations was 5 mg/mL. Three samples of each preparation were stored in 2-oz, amber glass prescription bottles in the dark under refrigeration at 4 degrees C. Immediately after preparation and at 7, 14, 21, 28, and 35 days, samples were visually inspected, tested for pH, and assayed in duplicate by high-performance liquid chromatography. On day 35, the mean percentages of the initial baclofen concentrations remaining were 95.9% in the suspension and 95.6% in the solution. The color, odor, and pH of the samples did not change appreciably over the study period. In an extemporaneously compounded oral liquid preparation in Simple Syrup, NF, stored in the dark under refrigeration, baclofen was stable for at least 35 days.

Administration, Oral↗
PubMed1993

Stability of midazolam hydrochloride in extemporaneously prepared flavored gelatin.

The stability of midazolam hydrochloride in flavored gelatin was evaluated after storage at 4 degrees C for 14 days and at -20 degrees C for 28 days. A flavored liquid gelatin mixture was prepared and mixed with midazolam hydrochloride injection in final concentrations of midazolam 1 and 2 mg/mL. Gelatin cups containing 5 and 15 mg of midazolam were prepared by measuring appropriate volumes of the gelatin stock solutions and were stored in a refrigerator at 4 degrees C or in a freezer at -20 degrees C. Immediately after preparation and at 7 and 14 days, three refrigerated and three frozen gelatin samples of each midazolam concentration were visually inspected, tested for pH, and assayed for midazolam concentration by high-performance liquid chromatography. The frozen gelatin samples were also evaluated at 21 and 28 days; three whole and three partial gelatin samples were assayed for midazolam content to determine the uniformity of drug distribution within each sample. All samples maintained greater than 96% of the initial midazolam concentration throughout the study. There was no appreciable change in color, odor, or pH. The midazolam content of the gelatin in the cups was uniform. An extemporaneously compounded preparation of midazolam hydrochloride in flavored gelatin was stable when stored for 14 days at 4 degrees C and for 28 days at -20 degrees C. Distribution of midazolam hydrochloride in the gelatin was uniform.

Drug Stability↗
PubMed1993

Stability and compatibility of fluconazole and aminophylline in intravenous admixtures.

The stability of aminophylline and fluconazole in intravenous admixtures containing both drugs was studied. Admixtures containing aminophylline 2.0 or 1.0 mg/mL and fluconazole 1.5 or 0.5 mg/mL in 5% dextrose injection or 0.9% sodium chloride injection were prepared. Each admixture was prepared in triplicate in glass containers and kept at 24 degrees C. Immediately after preparation and at one, two, and three hours, samples were visually inspected, tested for pH, and assayed in duplicate by high-performance liquid chromatography for theophylline concentration and fluconazole concentration. More than 98% of the initial aminophylline and fluconazole concentrations remained at each test interval. There was no visible evidence of precipitation, gas formation, or color change. No appreciable change in pH occurred during the study period. Aminophylline 1.0-2.0 mg/mL and fluconazole 0.5-1.5 mg/mL admixed in 5% dextrose injection or 0.9% sodium chloride injection were stable and compatible for up to three hours at 24 degrees C.

Aminophylline↗
PubMed1992

Altered steady-state levels of the messenger RNAs for c-myc and p53 in L1210 cell lines resistant to deoxyadenosine.

L1210 cell lines, selected for resistance to deoxyadenosine due to the loss of allosteric inhibition of ribonucleotide reductase by dATP, had altered steady-state levels of the mRNAs for c-myc, fos, and p53. Wild-type L1210 cells had constitutive steady-state levels of c-myc and p53 with little or no fos mRNA. Two different deoxyadenosine-resistant cell lines (Y8 and ED2) had elevated steady-state levels of c-myc and fos but essentially no p53 mRNA. Hydroxyurea-resistant L1210 cells had the same levels of c-myc, fos, and p53 as the wild-type cells. There was no amplification of the gene for c-myc in the Y8 or ED2 cell lines. The half-life for c-myc mRNA was essentially the same in the wild-type and the Y8 and ED2 cells. Nuclear runoff experiments showed that the rates of transcription for c-myc in the Y8 and ED2 cells were elevated and could account for the increased steady-state levels of c-myc in these two cell lines. The transcription rate for p53 mRNA was not decreased in the Y8 and ED2 cells and therefore did not account for the loss of the steady-state levels of p53 in the cells. Cycloheximide treatment of the Y8 and ED2 cells resulted in a marked increase in the steady-state p53 mRNA level, indicating that a protein which was rapidly turned over was responsible for the extremely short half-life of p53 mRNA in these two cell lines.

Animals↗
PubMed1992

The accuracy of antenatal ultrasonography in identifying renal abnormalities.

OBJECTIVE: To determine the accuracy of measuring antenatal renal pelvic diameter for prediction of renal abnormalities. RESEARCH DESIGN: Prospective evaluation of all pregnant women undergoing ultrasonography. SETTING: A teaching hospital providing primary and referral maternity care. PARTICIPANTS: Fifty-six pregnant women with suspected fetal hydronephrosis or cystic lesions identified from 7500 ultrasonograms over 3 years. METHODS: Antenatal renal pelvic diameter was measured in the anteroposterior dimension. Neonates underwent postnatal ultrasonography after day 3 of life; if the results were abnormal, a cystogram and renal diuretic scan were obtained. RESULTS: None of 50 kidneys 15 mm or smaller in anteroposterior pelvic diameter had obstruction; 11 (79%) of 14 kidneys larger than 15 mm were obstructed or demonstrated vesicoureteral reflux. Of 12 kidneys believed to be multicystic before birth, five (42%) proved to have hydronephrosis. CONCLUSIONS: Since the majority of fetuses with suspected hydronephrosis proved to be normal, parents should not be unduly alarmed by the physician. Renal pelvic diameter of more than 15 mm is strongly predictive of hydronephrosis. Since severe hydronephrosis is treatable and can be mistaken for a multicystic kidney antenatally, full radiologic evaluation is needed soon after birth.

Congenital Abnormalities↗
PubMed1992

Measuring the comparative efficacy of antibacterial agents for acute otitis media: the "Pollyanna phenomenon".

In randomized, double-blind trials of antibiotic therapy for acute otitis media that determined both clinical and bacteriologic outcomes, clinical success rates were (93%) 236 of 253 for patients with bacteriologic success, (62%) 25 of 40 for those with bacteriologic failure, and (80%) 124 of 155 for those with nonbacterial acute otitis media. These rates were used to calculate the effectiveness of three strategies for assessing drug efficacy: (1) tympanocentesis and culture before and during therapy (bacteriologic efficacy), (2) tympanocentesis before therapy and assessment of clinical efficacy in bacterial acute otitis media, and (3) no tympanocentesis and assessment of clinical efficacy in clinical (total) acute otitis media. For a drug with a bacteriologic efficacy of 100%, calculated clinical efficacy was 93% for bacterial acute otitis media and 89% for clinical acute otitis media. For a drug with bacteriologic efficacy of 27%, a rate consistent with no antibacterial therapy, efficacy was 71% for bacterial acute otitis media and 74% for clinical acute otitis media. We conclude that if efficacy is measured by symptomatic response, drugs with excellent antibacterial activity will appear less efficacious than they really are and drugs with poor antibacterial activity will appear more efficacious than they really are. The predominant phenomenon is that drugs with poor antibacterial activity will appear to be clinically effective in the treatment of acute otitis media.

Acute Disease↗
PubMed1992

Abnormal cardiovascular responses induced by localized high power microwave exposure.

A hypothesis of microwave-induced circulatory under perfusion was tested in ketamine anesthetized rats whose heart rate, mean arterial pressure, pulse pressure, respiration rate, and body temperatures were monitored continuously. Fifty-eight ventral head and neck exposures in a waveguide consisted of sham-exposure and exposure to continuous wave (CW) and pulsed 1.25 GHz microwaves for 5 min. The 0.5 Hz (10 microseconds, 2 W average) and 16 Hz (1 microsecond, 6.4 W average) pulse-modulated microwaves were delivered at 400 kW peak power. The CW microwaves were 2 and 6.4 W. The average specific absorption rate was 4.75 W/kg per watt transmitted in the brain and 17.15 W/kg per watt transmitted in the neck. Respiration rate and mean arterial pressure were not altered. Changes in heart rate and pulse pressure were observed in rats exposed to higher power (16 Hz pulses and 6.4 W CW) but not to the lower average power microwaves (0.5 Hz pulses and 2 W CW). Depression of pulse pressure, an indication of a decrease in stroke volume, and increased (tachycardia) or decreased (bradycardia) heart rate were noted in presence of whole-body hyperthermia. The cardiac output of those animals exposed to higher average power microwaves was considered to be below normal as hypothesized. Decreased cardiac output and normal mean arterial pressure resulted in an increase in the total peripheral resistance which was contrary to the anticipated thermal response of animals.

Animals↗
PubMed1992

Stability of fluconazole and amino acids in parenteral nutrient solutions.

The stability of fluconazole and amino acids in parenteral nutrient (PN) solutions was studied. Amino acids at three concentrations (1.0%, 2.5%, and 5.0%) with 25% dextrose injection were combined with a high (1.75 mg/mL) or a low (0.5 mg/mL) concentration of fluconazole to form six combinations of PN solution and fluconazole. The solutions were visually inspected for precipitate, color change, or gas formation and tested for pH. By using high-performance liquid chromatography, the solutions were assayed for fluconazole concentration at zero, one, and two hours after preparation. The PN solution containing fluconazole 1.75 mg/mL and 5.0% amino acids was assayed for 14 amino acids at the same time points. There was no visual evidence of incompatibility in any of the fluconazole and PN solutions, and the pH of the solutions did not vary appreciably throughout the study period. The mean percentage of initial fluconazole concentration remaining at one and two hours was greater than 97% for all of the solutions studied. The mean percentage of initial amino acid concentration remaining at one and two hours was greater than 93% for each of the 14 amino acids assayed. When fluconazole 0.5 mg/mL or 1.75 mg/mL is mixed with PN solution containing 1.0%, 2.5%, or 5.0% amino acids and 25% dextrose injection, both fluconazole and amino acids are stable for up to two hours.

Amino Acids↗
PubMed1992

Gentamicin pharmacokinetics in term neonates receiving extracorporeal membrane oxygenation.

Extracorporeal membrane oxygenation (ECMO) may affect the pharmacokinetics of certain drugs. The objectives of this study were to determine (1) the pharmacokinetics of gentamicin in neonates on ECMO and compare them to reported values for a similar patient population not on ECMO, (2) if the pharmacokinetics of gentamicin differ between venous-venous and venous-arterial bypass, and (3) if the pharmacokinetics of gentamicin are affected by oxygenator surface area (0.6 m2 vs 0.8 m2 oxygenators). The medical records of 29 term neonates who received gentamicin while on ECMO were reviewed. Data collected included gentamicin dosage, peak and trough serum concentrations determined at steady state, duration of treatment, time on ECMO, daily weights, and pertinent laboratory values. An initial dosage of gentamicin 2.5 mg/kg every 18 hours is suggested for term neonates on ECMO. Dosage adjustments should be based on gentamicin serum concentrations, and modifications may also be required after ECMO.

Bacterial Infections↗
PubMed1992

Stability of an extemporaneously compounded clonidine hydrochloride oral liquid.

The stability of clonidine hydrochloride in an extemporaneous oral liquid formulation refrigerated for 28 days was studied. A suspension was prepared by grinding commercially available 0.2-mg clonidine hydrochloride tablets, adding Purified Water, USP, to form a paste, and then adding Simple Syrup, NF. A control solution was prepared from analytical grade clonidine hydrochloride powder in Simple Syrup, NF. The final concentration of clonidine hydrochloride in both formulations was 0.1 mg/mL. Three samples of each preparation were stored in 2-ounce amber glass prescription bottles in the dark at 4 degrees C. Immediately after preparation and at 3, 7, 14, 21, and 28 days, samples were visually inspected, tested for pH, and assayed in duplicate by high-performance liquid chromatography. On day 28, the mean percentages of the initial clonidine hydrochloride concentrations remaining were 92.4% in the suspension and 93.7% in the solution. The color, odor, and pH of the samples did not change appreciably over the study period. An extemporaneously compounded oral liquid preparation of clonidine hydrochloride in Simple Syrup, NF, is stable under the conditions studied for up to 28 days.

Chromatography, High Pressure Liquid↗
PubMed1992

Prevention of Lyme disease.

Lyme disease and the use of tick repellents and physical protective measures to prevent the disease are discussed. Lyme disease is a multiple-organ-system, immune-mediated inflammatory disorder transmitted by the bites of ixodid ticks infected with Borrelia burgdorferi. An individual is at greatest risk for infection when a tick has been attached to the skin for more than 24 hours. Lyme disease occurs in three stages and may affect the skin, nervous system, cardiac system, and joints. Antimicrobials used in management consist primarily of penicillins, cephalosporins, tetracyclines, and erythromycin. Tick repellents are divided into those applied to the skin and those applied to clothing. Skin repellents include N,N-diethyl-meta-toluamide (DEET), 2-ethyl-1,3-hexanediol, and dimethyl phthalate. Permethrin is by far the most effective clothing repellent. DEET plus a permethrin-containing clothing repellent offers the best overall protection. The adverse effects of repellents are minimal, but cases of hypersensitivity have been reported, especially in children. Physical measures to prevent tick bites include avoiding tick-infested areas, wearing light-colored clothing for easy identification of crawling ticks, regularly checking the body and pets for ticks, wearing protective garments and closed-toed shoes, and removing attached ticks promptly by using tweezers or forceps to apply a steady upward pull. A vaccine for the active immunization of humans against Lyme disease remains to be developed. Although antimicrobial therapy is available for persons with Lyme disease, the best approach for those who may be exposed to infected ticks is to apply topical skin or clothing repellents and to practice common-sense measures of physical protection.

Animals↗