Enhancing the Catalytic Activity of Pd Nanocatalysts for Anion Exchange Membrane Direct Ethanol Fuel Cells by Functionalizing Vulcan XC-72 with Cu Organometallic Compounds.

The most widely used support in low-temperature fuel cell applications is the commercially available Vulcan XC-72. Herein, we report its functionalization with the home-obtained mesityl copper (Cu-mes) and Cu coordinate (Cu(dmpz)L2) organometallic compounds. Pd nanoparticles are anchored on the supports obtaining Pd/CCu-mes, Pd/CCu(dmpz)L2, and Pd/C (on nonfunctionalized support). The polarization curves of the ethanol oxidation reaction (EOR) show that Pd/CCu-mes and Pd/CCu(dmpz)L2 promote the reaction at a more negative onset potential, i.e., E onset = 0.38 V/reversible hydrogen electrode (RHE), compared to 0.41 V/RHE of Pd/C. The mass current density (j m) delivered by Pd/CCu-mes is considerably higher (1231.3 mA mgPd -1), followed by Pd/CCu(dmpz)L2 (1001.8 mA mgPd -1), and Pd/C (808.3 mA mgPd -1). The enhanced performance of Pd/CCu-mes and Pd/CCu(dmpz)L2 for the EOR (and tolerance to CO poisoning) is attributed to a shift of their d-band center toward more negative values, compared to Pd/C, because of the formation of PdCu alloyed phases arising from the functionalization. In addition, laboratory-scale tests of the anion exchange membrane-direct ethanol fuel cell assembled with Pd/CCu-mes show the highest open circuit voltage (OCV = 0.60 V) and cell power density (P cell = 0.14 mW cm-2). As a result of its high catalytic activity, Pd/CCu-mes can find application as an anode nanocatalyst in AEM-DEFCs.

Reoviruslike agent in stools: association with infantile diarrhea and development of serologic tests.

Reoviruslike particles were visualized by electron microscopy in stool filtrates prepared from stools of infants and young children with severe acute gastroenteritis. Patients who had such particles in their stools and whose paired acute and convalescent serums were tested developed an antibody response to the reoviruslike agent, which was measured by immune electron microscopy and by complement fixation. The reoviruslike agent was antigenically related to the epizootic diarrhea of infant mice virus and the Nebraska calf diarrhea virus.

Ceftazidime in the treatment of meningitis in infants and children over one month of age.

Ceftazidime, a new beta-lactamase-resistant cephalosporin, was compared with a combination of ampicillin and chloramphenicol for the treatment of meningitis in 100 infants and children aged one month to 15 years. In this open, randomized trial conducted in the Dominican Republic, 61 patients received 50 mg/kg of ceftazidime intravenously every eight hours; 39 received ampicillin plus chloramphenicol in conventional dosages. Seventy-eight of the patients had discernible isolates in samples from cerebrospinal fluid, six had a positive diagnostic Directogen result, and the remainder either had miscellaneous pathogens evident in samples of cerebrospinal fluid, bacteriologic growth in cultures of blood samples only, or no bacteriologic growth in cultures of either cerebrospinal fluid or blood. Among patients with discernible etiologic agents in samples of cerebrospinal fluid, 11 of 57 (19 percent) ceftazidime-treated patients died, and five of 27 (19 percent) patients treated with the combination died. Mortality by pathogen was as follows for patients who received ceftazidime or ampicillin plus chloramphenicol, respectively: Hemophilus influenzae, two of 27 (7 percent) and one of 15 (6 percent); Streptococcus pneumoniae, six of 12 (50 percent) and two of five (40 percent); Neisseria meningitidis, none of 11 (0 percent) and one of six (17 percent); and Salmonella, neither of two (0 percent) and one of one (100 percent). Overall mortality in the ceftazidime group was 20 percent versus 21 percent in the combination group. No significant toxicities were noted in the patients treated with ceftazidime.

Ampicillin-resistant Haemophilus in the oropharynx: prevalence in three groups of young, middle-class children.

Infections caused by ampicillin-resistant Haemophilus influenzae type b are prevalent in Fairfax County, VA. In order to gain information on pharyngeal carriage of ampicillin-resistant H influenzae, oropharyngeal cultures were obtained from 249 young children. The study population comprised three groups: 90 healthy children (group A), 79 children who had finished a ten-day course of amoxicillin treatment for acute otitis media (group B), and 80 children who were brought to our office for treatment of purulent nasopharyngitis (group C). Approximately 60% of the children in each group carried Haemophilus in the oropharynx. H parainfluenzae was the predominant oropharyngeal species in group 1. H influenzae was predominant in the other two groups. Ampicillin-resistant Haemophilus sp organisms were recovered from 16% of children in group A, 25% of those in group B, and 17% of patients in group C. Recent exposure to ampicillin was associated with an increase in the recovery of ampicillin-resistant strains of Haemophilus.

Complications of sinusitis in children.

Eight patients (6 to 15 years of age) who had periorbital cellulitis and other complications of sinusitis were studied. Both ethmoid and maxillary sinusitis were present in four patients, frontal sinusitis in two, and ethmoid sinusitis and pansinusitis in one patient each. Subdural empyema occurred in four patients, in one case accompanied by cerebritis and brain abscess and in another by meningitis. Periorbital abscess was present in two children who had ethmoiditis. Alveolar abscess in the upper incisors was present in two children whose infection had spread to the maxillary and ethmoid sinuses. Anaerobic bacteria were isolated from the infected sinuses in all the patients. These were seven isolates of Bacteroides sp, four Fusobacterium sp, three microaerophilic streptococci, three Gram-positive anaerobic cocci, and two Veillonella sp. There was only one aerobic isolate recovered, a group F beta-hemolytic. Streptococcus. Surgical drainage and appropriate antimicrobial therapy resulted in complete eradication of the infection in all patients. The role of anaerobic bacteria in sinus infection and its subsequent complication is discussed. Given the possible serious complications of this disease, the early recognition of sinusitis in children and the institution of appropriate antimicrobial and surgical therapy are of great clinical importance.

Pediatric Plasmodium falciparium malaria: a ten-year experience from Washington, DC.

From 1983 to 1992 a total of 64 children were admitted with a diagnosis of malaria to Children's National Medical Center in Washington, DC. Specific etiology is available in 59 of 64. Of these 59 cases 52 (88%) were caused by Plasmodium falciparum. Fifty-one of 52 infections were acquired in Africa, 35 (67%) of these in traveling United States citizens. Eleven (21%) of 52 children were initially admitted to the Intensive Care Unit for i.v. quinidine or quinine therapy. Eight (73%) of these 11 patients compared with 12 (29%) of 41 general ward admissions had been misdiagnosed within 10 days before admission (P = 0.012). Five of 11 Intensive Care Unit patients underwent exchange transfusion. One child died and one was left with severe neurologic deficit. Malaria must be considered in the differential diagnosis for any febrile child who has traveled to or from a malarious area within the previous 12 months. Delayed diagnosis of pediatric Plasmodium falciparum malaria is associated with an increased severity of illness. Because of the frequency of international travel, United States physicians will need to be familiar with the presentation and management of imported P. falciparum malaria.

Increasing incidence of penicillin- and ampicillin-resistant middle ear pathogens.

During a 13-month period ending in January, 1995, we obtained 159 samples of middle ear exudate through tympanocentesis (n = 155) or acute spontaneous otorrhea (n = 4) from 151 children enrolled in therapeutic trials of acute otitis media in a pediatric practice in Northern Virginia. Their ages ranged from < 1 to > 6 years of age (mean, 35 months; median, 22 months). Precise diagnostic criteria for acute otitis media always included bulging outward of all or part of the eardrum, opacification of the eardrum regardless of color and impaired mobility to positive and negative pressure via the pneumatic otoscope. Bacterial pathogens were isolated from middle ear fluid in 95% of these children: Streptococcus pneumoniae was recovered from 61 (37%); Haemophilus influenzae from 45 (27%); Moraxella catarrhalis from 41 (25%); Group A streptococcus from 6 (4%); Staphylococcus aureus from 4 (2%); and no growth or microbes of uncertain significance from 8 (5%). Six of the patients had mixed bacterial cultures; 2 of the 6 had at least one ampicillin-resistant bacteria, and a third had 2 ampicillin-resistant bacteria. Eight patients who failed to improve with antimicrobial treatment had a second tympanocentesis performed or developed spontaneous drainage; on that follow-up culture 3 of 8 cultures had different microorganisms; and 5 of the 8 bacterial specimens were resistant to ampicillin or penicillin. Twenty-one percent of the S. pneumoniae strains recovered from the middle ear were resistant to penicillin. Sixty-two percent of the H. influenzae and 98% of the M. catarrhalis isolates were resistant to ampicillin. Overall bacteria resistant to penicillin or ampicillin were recovered in 54% of middle ear fluid from 46 patients who had received a beta-lactam antibiotic in the preceding month as well as in 57% of middle ear fluids from 105 patients who had not. The empiric use of amoxicillin for treatment of acute otitis media should be reexamined in our community particularly in those who appear ill, have a high fever or have severe unremitting otalgia.

Treatment of Pseudomonas meningitis with ceftazidime with or without concurrent therapy.

In ongoing studies in Europe and the United States, 10 pediatric patients with bacterial meningitis caused by Pseudomonas species were treated with ceftazidime. Pseudomonas aeruginosa was isolated from the CSF of 7 patients and other Pseudomonas species from the remaining 3. Eight of the 10 patients had received previous antimicrobial treatment which included aminoglycosides in 6, along with ticarcillin and ureidopenicillins in 3. Ceftazidime was administered 10 to 42 days in dosages ranging from 109 to 300 mg/kg/day. Seven of the 10 patients received ceftazidime only for 10 to 42 days. The other 3 patients received amikacin in 2 and gentamicin and tobramycin in the other. Seven patients were cured clinically and 3 died; 9 were cured bacteriologically and one who was presumed cured on the basis of clinical response subsequently died. Sterilization of the cerebrospinal fluid occurred at 48 hours to 12 days. Ceftazidime appears useful in treating bacterial meningitis caused by Pseudomonas species.

Aerosolized ribavirin in the treatment of patients with respiratory syncytial virus disease.

Thirty children 1 to 33 months of age were enrolled in a study of aerosolized ribavirin therapy for respiratory syncytial virus lower respiratory tract illness. Twenty patients received ribavirin and 10 received placebo. There were no significant differences between the groups in chronologic or gestational age or in days of illness prior to admission. Among patients with pneumonia 17% of 6 placebo patients vs. 64% of 11 ribavirin patients had radiographic evidence that multiple lung lobes were affected (P = 0.06). Placebo patients received 42.5 to 94.7 hours (mean, 58.6) of aerosol therapy, whereas ribavirin patients received 36.3 to 95.6 hours (mean, 55.7). Seventy-seven percent of all study patients were discharged within 5 days of starting treatment. Severity of illness was evaluated daily using a scale of 0 (normal) to 4+ (most severe). Ribavirin patients initially had a mean severity score 0.5 higher than placebo patients. By Day 2, their rate of improvement was significantly greater than that of placebo patients (P = 0.001). By Day 5, 36% of ribavirin patients with rales showed improvement, whereas rales persisted in 100% of placebo patients. The rate of improvement of oxygen saturation from first to last day of treatment was statistically significant only for ribavirin patients (P = 0.02). On Day 3, 65% of ribavirin patients (13) vs. 50% (5) placebo patients shed 10(-0.5) 50% tissue culture infective dose virus per 0.2 ml of nasal wash. No side effects or toxicity were associated with aerosol therapy. A short course of ribavirin treatment (approximately 3 days) proved safe and beneficial.

Prospective, randomized, investigator-blinded study of the efficacy and safety of meropenem vs. cefotaxime therapy in bacterial meningitis in children. Meropenem Meningitis Study Group.

OBJECTIVES: To compare the efficacy and safety of meropenem with cefotaxime for the treatment of infants and children with bacterial meningitis. METHODS: Infants and children with strongly suspected or documented bacterial meningitis were randomly assigned in a prospective multicenter study to receive either meropenem or cefotaxime. Patients were assessed at the end of therapy and at 5 to 7 weeks and 5 to 7 months after the end of treatment for the presence of neurologic and sensory neural sequelae. RESULTS: A total of 258 children were randomized to either treatment group. A further 8 patients with suspected pneumococcal meningitis were treated with meropenem without randomization. Of the randomized patients 154 were fully evaluable, 79 in the meropenem group and 75 in the cefotaxime group. At the end of treatment there were no significant differences in clinical outcome between the two treatment groups. Clinical cure with or without sequelae was achieved in 97 and 96% of the meropenem- and cefotaxime-treated patients, respectively. At the end of treatment and at 5 to 7 weeks, 46 and 54% of meropenem patients were cured with no sequelae, respectively. Corresponding results for cefotaxime patients were 56 and 58%. All pathogens were eradicated. In total 37 patients had seizures during treatment, 15 (12%) in the meropenem and 22 (17%) in the cefotaxime group. None of the seizures was considered to be drug-related. CONCLUSIONS: This trial shows that meropenem is suitable therapy for bacterial meningitis in infants and children and that it offers an efficacy and safety profile similar to that of cefotaxime.

Cefixime vs. cefaclor in the treatment of acute otitis media in children: a randomized, comparative study.

The efficacy of cefixime was compared with that of cefaclor in the treatment of 63 patients with acute otitis media. Patients received either a single dose of cefixime (8 mg/kg/day) or 3 divided doses of cefaclor (40 mg/kg/day). On the basis of otoscopic and tympanometric results at 10 to 14 days after the start of treatment, 28 (97%) of 29 cefixime-treated patients and 25 (78%) of 32 cefaclor-treated patients had resolution of acute otitis media. The clinical cure rate associated with all organisms was 94% for cefixime (16 of 17 isolates) and 68% (13 of 19 isolates) for cefaclor. The cure rate for Streptococcus pneumoniae was 12 of 12 (100%) for cefixime and 7 of 7 (100%) for cefaclor; the cure rate for Haemophilus influenzae (which includes 2 patients with mixed infections) was 3 of 4 (75%) for cefixime and 2 of 7 (29%) for cefaclor. One clinical relapse occurred among 29 cefixime-treated patients; however, at 28 days 9 recurrences were observed. Three of 25 (9%) cefaclor-treated patients failed and 4 (13%) relapsed at 10 to 14 days, an additional 2 (10%) experienced recurrence by Day 28. Eight (28%) cefixime-treated patients experienced adverse events (7 gastrointestinal and 1 diarrhea and rash); 8 (25%) cefaclor-treated patients experienced adverse events (all gastrointestinal). Our data suggest that both at end of therapy and for 14 days thereafter, cefixime given once a day for acute otitis media is clinically equivalent to cefaclor given 3 times a day.

Escherichia coli virulence factors and 99mTc-dimercaptosuccinic acid renal scan in children with febrile urinary tract infection.

Correlation of virulence factors of Escherichia coli with renal inflammation documented by 99mTc-dimercaptosuccinic acid renal scan was undertaken in 59 children with febrile urinary tract infections to identify more accurately the role of bacterial virulence factors in the development of pyelonephritis. P fimbriae were present in 63% of isolates from the positive scan group and 83% of those from the negative scan group (P = 0.126). Multivariate regression analysis showed no significant role for established E. coli virulence factors in the development of pyelonephritis. The pap genome was independently associated with negative scan (P less than 0.007) and with the absence of reflux (P = 0.031). E. coli pyelonephritogenic clone O16:K1:H6 was isolated from negative scan patients and did not produce hemolysin. We conclude that P fimbriae are important in the development of febrile urinary tract infection regardless of the level of infection. Virulent E. coli clones described in prior Scandinavian urinary tract infection studies were not common causes of pyelonephritis in our patient population.

Longitudinal study of rotavirus infection and gastroenteritis in families served by a pediatric medical practice: clinical and epidemiologic observations.

During 29 months of prospective longitudinal study of diarrhea in the home, human rotaviruses (HRVs) infected one or more members in 51% of 65 families, 35 of 126 children (28%) and 16 of 124 adults (13%). Within the 33 affected families, 57% of 62 children and 25% of 65 adults were infected. HRV gastroenteritis peaked at 40/100 person years at ages 12 to 23 months and decreased to 5 episodes/100 person years in adults. Among 25 children 0 through 36 months of age who had HRV infection, 88% were symptomatic. Of the 22 children with symptomatic HRV infection, 1 required hospitalization and 8 were seen by their physician for supportive care. HRVs were found in 12% of 216 stools obtained during gastrointestinal illness, but in only 0.2% of 1238 non-illness stools tested. HRV infections were noted as early as October and as late as April. Of 33 families who were studied for 2 seasons, at least 1 individual in each of 3 families experienced HRV infections in both years, but only one, an adult, shed virus and had symptoms in both seasons.

Haemophilus influenzae biotype III infections in children and report of three unusual cases.

Three hundred thirty seven Haemophilus influenza isolates from infections in children were studied to determine the relationship between H. influenza, biotype III, and specimen source. Eighteen per cent (60) of the isolates were H. influenza biotype III. Of these, 70% were from the eye, 18% from the respiratory tract, 7% from the ear and 2% from blood. Although conjunctivitis was the most common clinical condition associated with H. influenza biotype III, three cases of systemic infection with this organism are presented: a 10-month-old female with pneumonia, a 17-year-old male with sepsis, and a 7-year-old male with endophthalmitis. This organism may be a significant pathogen depending on the clinical setting. Increased awareness of its importance will lead to more reports of its isolation.

Prospective follow-up and pulmonary functions from a placebo-controlled randomized trial of ribavirin therapy in respiratory syncytial virus bronchiolitis. Ribavirin Study Group.

OBJECTIVE: To determine any long-term differences in adverse effects and pulmonary function between infants with respiratory syncytial virus and lower respiratory tract infection who were treated with ribavirin and a control group. STUDY DESIGN: Long-term follow-up included enumeration of episodes of respiratory illness, wheezing, and pneumonia and, ultimately, administration of pulmonary function tests (PFTs). Pulse oximetry was done at each visit. During the first 3 years we conducted follow-up in the fall and spring. In years 4 and 5 we conducted 1 visit per year. During years 5 through 7 we conducted PFTs, and starting with year 7 a methacholine chloride challenge was done if forced expiratory volume in 1 second (FEV1) was greater than 70% of predicted value. RESULTS: We prospectively enrolled (December 1983 to February 1985) in a randomized trial of ribavirin vs placebo children who were previously healthy, were premature, or had chronic pulmonary disease. One pulmonologist (R.F.; blinded) scored and interpreted the results of the PFTs. We studied 42 patients aged 1 to 33 months; 2 patients died (1 receiving ribavirin and 1 receiving placebo) and 5 patients receiving placebo were lost to follow-up; 35 patients (24 taking ribavirin and 11 taking placebo) attended 212 visits. Four patients were premature (3 in the ribavirin and 1 in the placebo group), and 3 of these had bronchopulmonary dysplasia (2 in the ribavirin and 1 in the placebo group). From years 1 to 3, there was more reactive airway disease, wheezing, and pneumonia in the placebo than in the ribavirin group (mean score, 22.3 for 12 placebo-treated patients vs. 15.8 for 23 ribavirin-treated patients; P = .07 by Kruskal-Wallis test); for all years, it was 22.0 for 11 placebo-treated patients vs. 16.0 for 22 ribavirin-treated patients (P = .10). After informed consent was given, 19 patients completed PFTs (13 receiving ribavirin and 6 receiving placebo); 7 of 13 ribavirin-treated patients (53%) had normal or mild PFT results vs. 0 of 6 placebo-treated patients (P = .04 by Fisher exact test). On methacholine challenge (7 ribavirin-treated patients and 5 placebo-treated patients), there was more reactivity in the placebo vs. the ribavirin group (exact P = .07). Scoring done by weighting for severity for 19 patients (13 ribavirin-treated patients and 6 placebo-treated patients) (even after correcting for asthma) showed a significant difference in favor of previously ribavirin-treated patients (exact P = .02). CONCLUSIONS: No outward effects were identified from ribavirin exposure. We observed no increase in reactive airway disease, wheezing, and pneumonia in the ribavirin compared with the placebo group. Weighted severity scores suggest long-term beneficial effect of ribavirin therapy; however, larger numbers should be evaluated.

Penicillin-resistant pneumococci from pediatric patients in the Washington, DC, area.

OBJECTIVE: To assess the prevalence and antimicrobial susceptibility of penicillin-resistant pneumococci (PRP) isolated from patients in a pediatric hospital. METHODS: All (108) isolates of Streptococcus pneumoniae recovered from usually sterile body sites between June 1, 1992, and May 31, 1993, were screened for susceptibility to penicillin by the E-test method. Minimum inhibitory concentrations of penicillin and other antibiotics were also determined by an agar dilution method for 10 PRP and 22 penicillin-susceptible strains. RESULTS: Fourteen isolates (12.9%) were PRP by the E-test; nine of these (8.3%) were intermediately resistant and five (4.6%) were highly resistant. All strains were sensitive to rifampin and vancomycin. Increased frequency of resistance to oral and parenteral cephalosporins and carbapenems was found among PRP; for most of these antibiotics, resistance exceeded 40% of the PRP. In addition, 20% of the PRP were resistant to macrolides and all penicillin-susceptible and PRP were resistant to a combination of trimethoprim and sulfamethoxazole. CONCLUSIONS: The decreased susceptibility to oral and parenteral cephalosporins, macrolides, a combination of trimethoprim and sulfamethoxazole, and carbapenems creates a significant problem in the treatment of pneumococcal infections in both ambulatory and hospitalized patients.

Ribavirin aerosol treatment of serious respiratory syncytial virus infection in infants.

Bronchiolitis is one of the most serious pulmonary infections commonly caused by respiratory syncytial virus (RSV). RSV disease occurs in yearly epidemics and is most severe in children 1 year of age or younger. Approximately 1 in 50 to 1 in 100 infants are hospitalized after their first infection, and mortality fluctuates between 0.5 and 5.0 per cent. Patients with underlying conditions such as congenital heart disease and bronchopulmonary dysplasia are at higher risk for morbidity and mortality. Methods for rapid diagnosis of RSV infection and the advent of specific therapy with aerosolized ribavirin have revolutionized the management of hospitalized patients with moderate to severe disease. A 3- to 5-day course of ribavirin plus supportive measures should be used in infants who prove to be infected by RSV and who are deteriorating on traditional supportive therapy, and/or who have underlying cardiac and/or pulmonary or immune defects.

Cefuroxime: mechanisms of action, antimicrobial activity, pharmacokinetics, clinical applications, adverse reactions and therapeutic indications.

Cefuroxime is a second generation cephalosporin with a broad antimicrobial activity against both Gram-positive and Gram-negative organisms. It has excellent in vitro activity against staphylococcal strains, streptococcal strains (other than enterococci), N. gonorrhoeae, H. influenzae and N. meningitidis. It also has excellent in vitro activity against members of the Enterobacteriaceae with the exception of Serratia and indole-positive Proteus. Ps. aeruginosa and B. fragilis are resistant. Cefuroxime is relatively free of serious side effects. It is metabolically stable, and most of it is excreted unchanged in the urine. Three fourths of it are distributed in the extravascular compartment. Blood levels exceed the in vitro minimum inhibitory concentrations for many important gram negative pathogens. Clinical studies have shown cefuroxime to be effective therapy for infections of soft tissue, respiratory tract, urinary tract, genital tract (caused by N. gonorrhoeae) and the central nervous system. Superinfections with Ps. aeruginosa and enterococcal strains may present a problem. In spite of excellent diffusion into bone and joint tissues, the available clinical data are too limited to make a recommendation for its use in bone and joint infections.

Draining ears in acute otitis media: reliability of culture.

The purulent exudates in the ear canal of 69 children who presented with acute otorrhea were cultured directly onto standard media. No effort was made to either suction out the exudate lying in the canal or to use antiseptic agents on the canal wall. Potential pathogens such as H. influenzae, S. pneumoniae and S. pyogenous were recovered from two-thirds of the patients who suffered spontaneous otorrhea. Reliable cultures can be obtained from such patients provided the cultures are plated expeditiously on solid agar.

Office myringotomy for acute otitis media: its value in preventing middle ear effusion.

Middle ear effusion (MEE) as a residual of treated acute otitis media was found in 49% of 776 children studied. No antibiotic singly or in combination, demonstrated superiority in reducing the incidence of MEE. Simple myringotomy, as a therapeutic modality in 415 children who presented with an acutely bulging painful eardrum, did not facilitate adequate drainage as 51% of such children, treated with simple myringotomy in addition to antibiotics, had MEE detected 10 days later. The incidence of MEE also occurred independently of the middle ear pathogen. Within six weeks, spontaneous resolution of the effusion occurred in 85% of the 382 children with MEE that was detected 10 days after acute otitis media.