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Biomedical subjects

J D Nelson

Publications and source records attributed to J D Nelson.

At least 127 records · Page 7Linked to original sources

Oral v topical erythromycin therapies for chlamydial conjunctivitis.

Results of oral and topical erythromycin therapy in 41 infants under 4 months of age with chlamydial conjunctivitis were evaluated in randomized clinical trial. After three weeks of treatment, relapse or reinfection of the eye occurred in four of 19 patients (21%) in the topical therapy group and in three of 22 patients (13.6%) in the oral therapy group (p less than .69). In the topical therapy group, chlamydiae were isolated from nasopharyngeal cultures of eight patients (42%) during or after therapy. Chlamydiae were eradicated from the nasopharynx of the six colonized patients treated with oral erythromycin. All relapses responded to a course of oral erythromycin therapy. We conclude that both modes of therapy are comparable for treatment of chlamydial conjunctivitis, but that oral therapy has the advantage of eradicating nasopharyngeal colonization.

Administration, Oral↗

Mecillinam alone and in combination with ampicillin or moxalactam in experimental Escherichia coli meningitis.

The activity of mecillinam, ampicillin and moxalactam alone and in combination was determined in a lapin meningitis model and a mouse meningitis model against two Escherichia coli strains isolated from infants with meningitis. Both strains were highly susceptible in vitro to the antibiotics, and responded well in systemic mouse protection tests (PD50 less than 4 mg/kg). Continuous infusion of mecillinam in the lapin model over nine hours was effective in sterilizing the CSF of three of four animals infected with one strain. This prompt bacteriologic response to mecillinam alone precluded the possibility of constant infusion administration for synergy studies. Therefore, single dose administration was used to demonstrate the synergistic potential of mecillinam with ampicillin in the lapin meningitis model against the E. coli Kl # 2 strain. The combination of moxalactam and mecillinam was synergistic against the E. coli Kl # 2 strain in the mouse meningitis model. The synergistic potential of these combinations could not be reliably predicted by in vitro tests, time kill curves or systemic mouse protection tests.

Amdinocillin↗

Melioidosis.

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Animals↗

Response to pneumococcal vaccination in children with nephrotic syndrome.

Serologic responses to a 14-valent pneumococcal vaccine were measured in 20 children with steroid-responsive idiopathic nephrotic syndrome. All patients were free of proteinuria and receiving either daily (five patients) or alternate-day (15 patients) prednisone in a dosage of 1-2 mg/kg/day at the time of vaccination. Patients on alternate-day steroids received the vaccine on a day prednisone was not given. The mean fold rise in antibody titer was found to be normal in these children when antibody levels measured 3-6 wk post-vaccination were compared to prevaccination levels. This serologic response has correlated well with a 3-yr follow-up of the patients, none of whom has developed peritonitis secondary to any pneumococcal types in the vaccine. Also described are three patients who developed pneumococcal peritonitis during this period despite prior vaccination; in two of these patients, the pneumococcal type was not included in the vaccine (types 6b and 10a) and in one patient the organism was not typed. It is concluded that in children with nephrotic syndrome pneumococcal vaccination confers good protection against types included in the vaccine despite the concomitant administration of steroids. However, the patients who developed peritonitis secondary to other pneumococcal types remind us that pneumococcus must still be considered as an etiologic agent for peritonitis in nephrotic children who have been vaccinated.

Adolescent↗

Diagnosis of giardiasis by counterimmunoelectrophoresis of feces.

The diagnosis of giardiasis is frequently difficult. In the present study, the techniques of microscopic examination of feces, duodenal fluid, and duodenal biopsy specimens were compared with counterimmunoelectrophoresis (CIE) of feces for Giardia lamblia antigen. New Zealand white rabbits were immunized with purified G. lamblia cysts and axial trophozoites, and the resulting antiserum was used for the detection of antigen. Of 276 patients with acute and chronic diarrhea studied using standard diagnostic methods, 66 patients had giardiasis: 62 by examination of feces; three, of duodenal fluid, and one, of duodenal biopsy specimens. CIE tests for G. lamblia fecal antigen had positive results for 65 of the 66 patients. The CIE test for Giardia fecal antigen appears to be as sensitive and reliable as the combined examination of feces and duodenal fluid.

Antigens↗

Benefits and risks of sequential parenteral--oral cephalosporin therapy for suppurative bone and joint infections.

Seventy-five infants and children with suppurative skeletal infections were managed with a sequential parenteral-oral regimen of cephalosporin antibiotic therapy. Initially, parenteral antibiotics (cefamandole for 48 patients and cefuroxime for 27 patients) were given for a median of 5 days. Oral therapy was with large doses of cefaclor (150 mg/kg/day) or cephalexin (100 mg/kg/day). Eight patients (11%) had inadequate serum bactericidal activity with cefaclor. Six of them were successfully managed with alternative oral antibiotics, and parenteral therapy resumed in one patient. Chronic disease developed in a child who was continued on oral cloxacillin therapy in spite of absent serum bactericidal activity. It is concluded that oral therapy can be successful for the majority of patients but that it is hazardous and not indicated if careful laboratory monitoring of compliance and serum bactericidal activity cannot be performed.

Acute Disease↗

Pharmacokinetics and bacteriological efficacy of cefoperazone, ceftriaxone, and moxalactam in experimental Streptococcus pneumoniae and Haemophilus influenzae meningitis.

The pharmacokinetics and bacteriological efficacy of cefoperazone, cefuroxime, ceftriaxone, and moxalactam were evaluated in the experimental rabbit meningitis model of Haemophilus influenzae type b or Streptococcus pneumoniae infection. The cerebrospinal fluid penetration of these beta-lactam antibiotics was from 3 to 14% and was greater in Haemophilus-infected that in pneumococcus-infected animals. With the exception of moxalactam, the antibacterial activity in cerebrospinal fluid and change in concentration of bacteria during therapy with the test drugs were comparable to those of penicillin G in pneumococcal infection. In animals infected with H. influenzae, cefoperazone, moxalactam, and ceftriaxone were as effective as chloramphenicol in reducing the bacterial counts in cerebrospinal fluid. Moxalactam and ceftriaxone produced the largest cerebrospinal fluid bactericidal titers against this beta-lactamase-producing strain of Haemophilus. On the basis of these data, it was concluded that ceftriaxone and cefoperazone were effective against both pathogens in this meningitis model, whereas moxalactam was effective against only Haemophilus, and cefuroxime was effective against only S. pneumoniae.

Animals↗

Pharmacokinetics of potassium clavulanate in combination with amoxicillin in pediatric patients.

Two dosages of a liquid suspension formulation of amoxicillin and potassium clavulanate were tested in 34 infants and children. The smaller dosage resulted in suboptimal plasma concentrations. With a greater dosage (3.3 mg of clavulanate per kg and 13.3 mg of amoxicillin per kg), the mean peak plasma concentrations were 1.6 micrograms clavulanic acid per ml and 4.9 micrograms amoxicillin per ml.

Amoxicillin↗

Pharmacokinetics and cerebrospinal fluid bactericidal activity of ceftriaxone in the treatment of pediatric patients with bacterial meningitis.

Single-dose pharmacokinetics of ceftriaxone were determined in 19 patients with proven bacterial meningitis. The dosage was 50 mg of ceftriaxone per kg. The plasma concentration time curve declined in a biexponential manner. The mean peak plasma concentration was 207 micrograms/ml, and the elimination half-life was 4 h. In 12 patients, multiple-dose pharmacokinetics were determined after a loading dose of 75 mg of ceftriaxone per kg, followed by 50-mg/kg doses every 8 h in 5 patients or every 12 h in 7 patients. The mean peak plasma concentration was 230 micrograms/ml after the first dose and 263 micrograms/ml after the last dose. Of 12 patients, 5 had trough values that were larger after multiple doses than after a single dose. Mean penetration of ceftriaxone into cerebrospinal fluid was 3.1%. The median cerebrospinal fluid bactericidal titer against the patients pathogens was greater than 1:1,024 and less than 1:2,048. The drug was well tolerated without adverse effects.

Bacteria↗

Pharmacokinetics of cefuroxime in infants and children with bacterial meningitis.

A total of 38 patients with bacterial meningitis received either 50 or 75 mg of cefuroxime per kg of body weight given as a 15-min intravenous infusion during the first to third days of therapy. The mean peak plasma concentrations of cefuroxime after doses of 50 and 75 mg/kg were 105 and 152 micrograms/ml, respectively. In five patients, pharmacokinetic values were determined after multiple doses of 50 mg of cefuroxime per kg every 6 h. The mean peak plasma concentrations were 120 micrograms/ml after the first dose and 130 micrograms/ml after the last dose. The concentrations at 6 h were 3.25 and 11.0 micrograms/ml after the first and last doses, respectively. The elimination half-life was approximately 1.5 h, and the apparent volume of distribution was 650 ml/kg. The plasma clearance rate was 195 to 198 ml/min per 1.73 m2. Penetration into the cerebrospinal fluid, expressed as the ratio of the cerebrospinal fluid to serum areas under the curve times 100, was 6.4% in patients given 50 mg of cefuroxime per kg and 10% in those who received 75 mg/kg. The cerebrospinal bactericidal activity in 27 patients was less than or equal to 1:8; only 2 patients had bactericidal activity of less than or equal to 1:2.

Cefuroxime↗

Metabolic response of normal man and insulin-infused diabetics to postprandial exercise.

Physical exercise is often performed during absorption of meals. We have characterized the metabolic response to 45 min of moderate exercise (approximately 55% of estimated maximal oxygen uptake) beginning 30 min after breakfast in seven healthy controls. Nine insulin-dependent diabetes were studied in an identical manner, with glycemia controlled by a closed-loop "artificial endocrine pancreas" controlled by a closed-loop "artificial endocrine pancreas" (AEP). Responses were compared to those during breakfast without exercise. In the controls, onset of exercise rapidly reversed the rise in both glycemia and insulin (IRI) that occurred with breakfast alone, both returning to fasting levels (glycemia, 80 +/- 3 mg/dl; IRI, 0.38 +/- 0.10 ng/ml). After exercise, small and transient increments occurred (glycemia, 33 +/- 6 mg/dl; IRI, 0.81 +/- 0.15 ng/ml). In the diabetics, prior overnight intravenous insulin normalized fasting glycemia (98 +/- 4 mg/dl), and its postbreakfast excursion was identical to that of controls, as were those of most measured substrates. Similarly, with exercise, glycemia returned rapidly to fasting levels, accompanied by an appropriate decrease in insulin infusion rates. "Free" IRI levels mirrored changes in infusion rates by the AEP, with a decrease in insulin requirement of 30% during exercise as compared to breakfast alone (P less than 0.05). Thus, in both diabetics treated with the AEP and in normals, the responses to postprandial exercise required rapid modulation of insulin delivery. To demonstrate the effect of postprandial exercise on preprogrammed open-loop insulin replacement, four diabetic subjects were studied during breakfast with and without exercise while receiving a fixed open-loop insulin infusion pattern (6.1 +/- 0.7 U over 140 +/- 8 min). The glycemic response to breakfast alone was entirely normalized. However, symptomatic hypoglycemia occurred in all subjects when exercise was initiated 30 min after breakfast. The diabetic responses to closed-loop insulin infusion provide important data in defining the appropriate preprogrammed open-loop insulin infusion pattern for postprandial exercise.

Adult↗

Comparative toxicities of methicillin and nafcillin.

In a prospective, randomized study, 75 infants and children were treated with methicillin sodium and 74 were treated with nafcillin sodium. The two groups were comparable with regard to age, sex, duration of therapy, types off illnesses, etiologic bacteria, and bacteremia. Clinical responses were also comparable. The frequencies of fever, rash, eosinophilia, neutropenia, anemia, and abnormal hepatic enzymes were the same in the two groups. Two patients in each group had transient hematuria early in their course that resolved despite continued antibiotic therapy. Definite urologic toxic effect did not occur in patients who received nafcillin, while four (5.3%) of the methicillin-treated patients were judged to have this complication. In addition, six patients (8%) who received methicillin had questionable evidence of urologic toxic effect. It is concluded that methicillin and nafcillin have comparable clinical efficacy and adverse effects, with the exception that definite urologic toxic effect has been observed with nafcillin therapy.

Adolescent↗

Furazolidone and quinacrine. Comparative study of therapy for giardiasis in children.

Furazolidone and quinacrine hydrochloride were compared for efficacy, toxicity, and ease of administration in 45 young children with giardiasis. With the initial course of therapy, the cure rate was 89% (17/19) with furazolidone and with quinacrine it was 64% (9/14) in children less than 5 years and 92% (11/12) in older children. Cure rates for all courses of therapy were 92% (24/26) with furazolidone and 53% (9/17) and 92% (12/13) in the younger and older children, respectively, treated with quinacrine. Quinacrine failure was usually due to severe vomiting. When re-treated with furazolidone, patients were cured. The disadvantages of furazolidone are the large volume of doses and the expense. In this study, furazolidone was more effective and better tolerated than quinacrine for the treatment of giardiasis.

Adolescent↗

Concentrations of antimicrobial agents in middle ear fluid, saliva and tears.

Antibiotics concentrations in middle ear fluid (MEF), saliva and tears were measured in children with persistent middle ear effusions undergoing tympanostomy tube placement. In 31 children given cefaclor, specimens of serum, saliva and MEF were collected at 0.5, 1, 2, 3 or 5 h after a dose. Another group of 37 children were randomized to receive a single dose of penicillin V, amoxicillin, ampicillin, erythromycin estolate, erythromycin ethylsuccinate, trimethoprim-sulfamethoxazole or cefaclor. Concentrations of antibiotics in saliva and tears bore no consistent relationship to those in MEF. Mean concentrations of all drugs in MEF were several-fold greater than the usual minimal inhibitory concentrations (MIC) of pneumococci, but only with trimethoprim and cefaclor were they greater than in usual MIC's for Haemophilus influenzae. Concentrations of antibiotics in MEF in persistent effusions were comparable to those previously reported in acute purulent effusions.

Amoxicillin↗

Recurrent infections and delayed separation of the umbilical cord in an infant with abnormal phagocytic cell locomotion and oxidative response during particle phagocytosis.

An 18-month-old infant with delayed separation of the umbilical cord and severe recurrent bacterial infections since the newborn period was found to have depressed polymorphonuclear leukocyte locomotion and oxidative metabolic response to particulate stimuli. Both her polymorphonuclear leukocytes and monocytes demonstrated a markedly delayed chemiluminescence response to zymosan, but there was a normal chemiluminescence response to soluble stimuli, phorbol myristate acetate and calcium ionophore A23187. The patient also had a marked delay in uptake of Staphylococcus aureus and Escherichia coli. The patient's polymorphonuclear leukocytes were normal morphologically, and myeloperoxidase was present in histochemical stains. The dichotomy between normal oxidative response to soluble stimuli and abnormal response to opsonized particulate stimuli, plus abnormal cell locomotion and phagocytosis, suggest an abnormality of cell membrane fluidity or contractility.

Bacterial Infections↗