Biomedical subjects
Publications and source records attributed to J D Nelson.
Two dosages (7.5 and 15 mg/kg of body weight) of LY163892 were given to infants and children, and five plasma specimens were collected for antibiotic assay during the ensuing 4 h. Peak concentrations of 12.6 and 18.7 micrograms/ml occurred at 45 min. The mean half-lives were 0.85 and 0.78 h, and the mean areas under the curve were 24.4 and 38.0 micrograms.h/ml.
LY163892 is a carbacephem antibiotic for oral administration with an antibacterial spectrum similar to that of cefaclor and amoxicillin-clavulanic acid. It has greater stability than cefaclor and greater activity against beta-lactamase-producing Haemophilus influenzae and Escherichia coli. LY163892 is less active than amoxicillin against streptococci and less active than amoxicillin-clavulanic acid against Branhamella catarrhalis but comparable against other pathogens.
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Suture removal following penetrating keratoplasty continues to plague surgeons as one of the most unpredictable aspects of this procedure. The patients presented here will detail three cases of endophthalmitis and one case of expulsive hemorrhage following suture removal. These events cannot be predicted. However, certain steps can be taken to minimize these potentially blinding complications. These steps include avoidance of through and through sutures, follow-up examination within 24 h of suture removal to look for signs of would leak, graft dehiscence or infection, use of appropriate antibiotics, elimination of dacryocystitis prior to keratoplasty, and particular vigilance in immunocompromised patients.
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Impression cytology refers to the application of cellulose acetate filter material to the ocular surface to remove the superficial layers of the conjunctival epithelium. Impression cytology has been found to be useful in assessing the ocular surface in various dry eye disorders, such as keratoconjunctivitis sicca (KCS), cicatricial ocular pemphigoid, and vitamin A deficiency. The technique is noninvasive, is easy to perform, causes minimal discomfort to the patient, and can be used to follow changes in the conjunctival ocular surface over time. With this method, the morphology of the conjunctival ocular surface can be studied and the degree of squamous metaplasia assessed. A specific criteria based on the appearance of the epithelial cells and the density of the goblet cells can be used to assign a grade (0-3) to the ocular surface. The grade of the ocular surface is related to the degree of squamous metaplasia and usually parallels the severity of clinical disease. Impression cytology can also be used to differentiate between various dry eye disorders. Disorders that are extrinsic or environmental (such as KCS) often affect the exposed interpalpebral ocular surface before the more protected inferior palpebral ocular surface. Intrinsic surface disorders (such as ocular pemphigoid) affect the palpebral, as well as the bulbar ocular surfaces, early in the disease.
In a retrospective review of 214 children with nephrotic syndrome seen at Children's Medical Center and Parkland Memorial Hospital in Dallas throughout the 20-year period from 1967 to 1986, 62 cases of primary peritonitis were identified in 37 patients (17.3% rate). Streptococcus pneumoniae was the major pathogen, accounting for 38% of the cases. An additional 27% of patients had negative culture results but were clinically responsive to penicillin. Gram-negative organisms were cultured from only 3% of patients; 5% were caused by alpha-streptococci and 2% each by enterococcus and anaerobes. In 23% of cases the cause was unknown. Our findings differ from the recent trend in the literature in which Gram-negative organisms associated with these infections are increasingly implicated. The incidence and bacteriology of peritonitis do not appear to have changed significantly during the 20-year period. Clinically, peritonitis was characterized by abdominal pain (98%), fever (95%), rebound tenderness (85%), and nausea and vomiting (71%). A total of 79% of patients were either in relapse or receiving steroid therapy at the time peritonitis was diagnosed; 13% had infiltrates visible on their chest radiographs. Based on our data, it seems reasonable to initiate antimicrobial therapy in nephrotic children with suspected peritonitis using a combination of penicillin plus either an aminoglycoside or a cephalosporin. This regimen should continue until culture results are available, unless Gram-positive diplococci are identified in a Gram-stained specimen of peritoneal fluid, in which case penicillin alone should suffice.
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We identified 35 patients who had epididymitis from 1965 to 1984 by hospital chart review. The common clinical presentation was swelling, pain, and erythema. Twenty-two patients had onset of symptoms within 24 hours of hospital admission. Surgery was performed in 31 patients, 22 of whom had cultures taken from the epididymis at the time of surgery. Bacterial agents were recovered from cultures of 13 patients: coagulase-negative staphylococci were identified in nine patients. In two patients, a polymicrobic cause was found. Six patients had associated urologic abnormality. Three patients had concurrent urinary tract infection. Urologic investigation should be undertaken in children younger than 2 years old and in older patients with recurrent episodes suspected to be due to reflux of urine and associated genitourinary abnormality.
Twenty-five infants and children with acute osteomyelitis (n = 7), suppurative arthritis (n = 11), or both (n = 7) were treated with imipenem and cilastatin sodium. Patients ranged in age from 5 months to 11.3 years. Needle aspiration of infected sites was performed in all patients, and 11 (44%) required further surgical drainage. Imipenem and cilastatin sodium in a dosage of 100 mg/kg/d was used for children 3 years of age or younger, while older ones received 60 mg/kg/d intravenously, divided in four equal doses. Bacterial pathogens were identified in 15 patients (60%): Staphylococcus aureus in five, Haemophilus influenzae b in four, Pseudomonas aeruginosa in two, Streptococcus pneumoniae in one, group A Streptococcus in one, Kingella kingae in one, and Citrobacter amalonaticus in one. All isolates were susceptible to imipenem in vitro. Imipenem and cilastatin therapy was continued for a median of six days followed by treatment with appropriate orally administered antibiotics. Median peak serum bactericidal titers after imipenem and cilastatin infusions were 1:512 for S aureus, 1:32 for H influenzae b, 1:512 for streptococci, and 1:16 for gram-negative rods. All but one patient with P aeruginosa osteomyelitis responded favorably to imipenem and cilastatin. The median duration until resolution of symptoms was six days. Imipenem and cilastatin infusions were well tolerated, and side effects included maculopapular rash in one patient, watery diarrhea in one, and mild transient elevation of alanine aminotransferase levels in three. Because of imipenem and cilastatin's unusually broad spectrum of activity and its relative safety, this drug combination can be used for the initial, empiric therapy of acute bone and joint infections in pediatric patients.
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The first step in treatment of chemical injuries to the eyes is immediate, thorough, and if necessary, prolonged irrigation. Ophthalmologic consultation should be obtained early in the course of treatment, and in severe injuries an anterior chamber tap (paracentesis) may be of benefit. Topical cycloplegics and antibiotics should be administered and a "bandage" contact lens placed to protect the corneal epithelium. If the eyelid is involved, care must be taken to protect the cornea and provide a moist local environment. Long-term care of the severely injured eye is fraught with difficulties, including glaucoma and recurrent corneal ulcerations.
The presence of viral infection was evaluated in 160 children older than three months with bacterial meningitis who were admitted to Children's Medical Center or Parkland Memorial Hospital, Dallas, TX, between October 1979 and March 1982. Results were compared with a single serologic specimen in 138 children without meningitis. A recent history of upper respiratory infection was obtained from 60% of patients, including 10/13 with pneumococcal, 9/16 with meningococcal, and 77/131 with Haemophilus influenzae meningitis. Viral infection was documented by serologic response (23.8%) or viral isolation (13.2%) in 63/160 (40%) of patients with meningitis. There were 23 positive cultures (one patient with both adenovirus and respiratory syncytial virus). Picornaviruses, including two rhinoviruses, were isolated from six of the 24 subjects without meningitis who had viral cultures. There were 69 serologic conversions in meningitis patients, with 12 patients converting to two organisms and four patients converting to three organisms. Viral diagnoses included: adenovirus, 32 children; respiratory syncytial virus, 14; influenza A, 8; influenza B, 4; parainfluenza (1, 2, and 3), 12; picornaviruses, 9; herpes simplex virus, 1; and cytomegalovirus, 1. Additionally, 6/15 seroconverted to Mycoplasma pneumoniae. The acute geometric mean serum antibody titers of meningitis patients were lower than those of the comparison group for adenovirus (3.5 vs. 6.6, p less than or equal to 0.001) and influenza B (1.2 vs. 1.6, p less than or equal to 0.05). Twenty nine of 131 patients with H. influenzae had evidence of recent adenovirus infection. Primary infection with adenoviruses and possibly influenza B or mycoplasma precedes development of bacterial meningitis in some patients and may be a predisposing factor.
An acellular pertussis vaccine principally containing two purified pertussis antigens, filamentous hemagglutinin and lymphocytosis-promoting factor, combined with diphtheria and tetanus toxoids was compared to conventional diphtheria-tetanus toxoids-whole cell pertussis for adverse effects and serologic responses in a group of 120 children who were from 18 to 24 months of age. Three vaccinations at 2, 4 and 6 months of age with diphtheria-tetanus toxoids-whole cell pertussis had been administered previously. Adverse effects occurred more frequently with the diphtheria-tetanus toxoids-whole cell pertussis than with diphtheria-tetanus toxoids-acellular pertussis vaccine. Fever occurred significantly more often and to a higher degree in the whole cell pertussis vaccine recipients with a peak difference occurring 6 hours after immunization (P = 0.00008). Local swelling, redness, warmth and tenderness at the injection site also occurred significantly more frequently following whole cell pertussis vaccination. No major sequelae were noted in either group. The antibody responses to lymphocytosis-promoting factor were similar for the two vaccines. The diphtheria-tetanus toxoids-acellular pertussis vaccine produced significantly lower pertussis agglutinin titers (P = 0.00001) but significantly higher antibody to filamentous hemagglutinin (P = 0.05) and to diphtheria (P = 0.03). The protective role of antibody to pertussis agglutinins vs. filamentous hemagglutinin and lymphocytosis-promoting factor continues as a central issue in the quest for a new pertussis vaccine. A clinical efficacy trial is needed.
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A survey of water samples to determine the efficacy of standard procedures for the isolation of environmental legionellae was conducted. Marked variations in intraspecies resistance to selective agents and treatments were observed, and in experiments with one of the isolates, the response was modified by culture conditions. Five selective procedures incorporating acid (pH 2.2) and heat (50 degrees C, 30 min) treatments, with and without plating on buffered charcoal-yeast extract agar supplemented with vancomycin (5 micrograms/ml), polymyxin B (60 U/ml), and cycloheximide (80 micrograms/ml), caused 5 to 99% decreases in viable counts of pure cultures in water suspensions. The differences in the responses of the cultures to the five treatments were statistically significant. Cells in retained samples of naturally contaminated water from which the original cultures had been isolated were significantly less sensitive than artificially grown isolates. The sensitivities of the laboratory-grown cells to the treatments were affected by the length of incubation on buffered charcoal-yeast extract agar. Whereas acid resistance increased after 24 h of incubation, resistance to the antibiotic mixture decreased.