Gram-negative enteric bacteremia in children in the Negev (1989-1994)

During 1989-1994, there were 322 episodes of Gram-negative enteric bacteremia in 308 children. The incidence increased from 31/100,000 in children younger than 15 years of age during 1989-1991, to 50/100,000 during 1992-1994. The most common pathogens were Klebsiella, E. Coli, Salmonella and Enterobacter. 39% of episodes were nosocomial and a significant increase was recorded for each species during the last 3 years of the study. Klebsiella represented the most common pathogen causing nosocomial bacteremia, while E. coli and Salmonella were the main pathogens causing community-acquired bacteremia. In this study in southern Israel, the incidence of Gram-negative enteric bacteremia was significantly higher in Bedouin children, with the exception of bacteremia due to Salmonella, which occurred mainly in Jewish children.     

Polarization at ion-exchange membranes in electrodialysis

In an attempt to investigate polarization phenomena (including substantial participation of H⁺ and OH^- in conduction) which seriously limit the production rates of electrodialysis units, current-voltage curves were measured in different sections along the tortuous flow path of an electrodialysis apparatus containing a single anion-exchange membrane of size 20″ × 18″. The electrical potential drops across this membrane and the adjacent solution layers were measured with silver electrodes terminating in exposed chloridized tips, placed in the two flow compartments adjacent to the anion-exchange membrane. While the measured current- voltage curves exhibit true limiting-current plateaus only in the last sections, all sections yield plateau currents after correction for the measured variation of coulombic efficiency. Moreover, these corrected curves are in fair agreement with those computed from the solution of the Nernst-Planck equations of ion migration, as developed in this paper to take due account of the variation of salt concentration along the flow path.     

The in vivo effect of recombinant human granulocyte-colony stimulating factor in neutropenic neonates with sepsis

The effects of recombinant granulocyte-colony stimulating factor (rhG-CSF) in neonatal neutropenia with presumed sepsis, which has a poor prognosis, were investigated. The study involved 14 neonates with presumed sepsis and neutropenia. Findings were compared with those from 24 historical controls. rhG-CSF (5 micrograms/ kg/day i.v. for 5 days) was administered immediately following diagnosis. Complete blood counts were obtained before and 24, 48, 72, 96 and 120 h after initiation of treatment. Neutrophil storage pool (NSP) was assessed (in 4 patients) before and after treatment. Statistical analysis was performed using one way analysis of variance. Treatment led to an increase in absolute neutrophil count (ANC) levels in 13/14 patients. At the end of treatment, the mean ANC was higher than that of controls (P = 0.007). There was a marked increase in the NSP of between 32% and 65% (P = 0.005). There were two clinical failures, one of whom was considered to have died from his underlying condition. There were no reports of clinical or haematological toxicity during treatment or follow up.     

"Drawing with nanotubes": creating nanowires with complex geometries by pulsed electrodeposition on self-organized carbon nanotube patterns

We present a new approach for the creation of nanowires with well-defined complex geometries by electrodeposition onto self-organized single-walled carbon nanotubes. The concept is demonstrated by generation of continuous Au nanowires with various geometries, including parallel arrays, serpentines, and coils. The generality of this approach is further illustrated by synthesizing Bi(2)Te(3) nanowires. Our concept of "drawing with nanotubes" offers to combine different material properties with complex geometries on the route to new functional nanosystems.     

Hyperparathyroidism associated with Raynaud's phenomenon--a case history

The authors describe a patient with hyperparathyroidism and Raynaud's phenomenon. This association was hitherto undescribed.     

Our experiences in processing maize (corn) germ oil

This paper discusses the properties and composition of corn oil. Influences of processing steps on oil quality are described, along with alkali and physical refining, degumming, bleaching, dewaxing, deacification-decodorization. A new method for wet degumming-bleaching and deacidification-deodorization is presented. Flowsheets and other data are given for a new 150 metric tons per day of corn oil plant.     

Early eradication of pathogens from middle ear fluid during antibiotic treatment of acute otitis media is associated with improved clinical outcome

OBJECTIVE: To determine the relation between early bacteriologic eradication and clinical outcome of acute otitis media (AOM) in infants and young children treated with various antibiotics. STUDY DESIGN: The study group consisted of patients ages 3 to 24 months seen at the Pediatric Emergency Room with: (1) symptoms and physical findings consistent with AOM of < or = 7 days duration; (2) no spontaneous perforation or tympanostomy tubes; (3) positive initial middle ear fluid culture; and (4) a follow-up to at least Day 10+/-2 of the study with a second culture performed 72 to 96 h after initiation of antibiotic treatment. Any patient with a positive middle ear fluid culture 72 to 96 h after initiation of antibiotic treatment was considered to have bacteriologic failure. Otologic evaluation was done by an otolaryngologist unaware of the culture results and of the study drug allocation. A clinical score based on body temperature, report of irritability and ear tugging observed by the parents and the appearance and redness of the ear drum as observed by the otolaryngologist was also used for clinical evaluation. RESULTS: The study group consisted of 123 patients, of whom 57 (46%) had positive middle ear fluid 72 to 96 h after initiation of antibiotic treatment. Clinical failure was observed in 21 of 57 (37%) patients in whom bacteriologic eradication did not occur vs. only 2 of 66 (3%) patients with bacteriologic eradication after 3 to 4 days of treatment (P < 0.001). Clinical score for both moderate and severe disease decreased significantly faster in those with bacteriologic eradication than in those in whom middle ear fluid was still culture-positive 72 to 96 h after initiation of treatment. CONCLUSION: Clinical failures in our population were associated with inability to eradicate the causative organisms of AOM from the middle ear fluid within 3 to 4 days after initiation of antibiotic therapy. Most patients (including those without bacteriologic eradication) improved after 3 to 4 days of treatment, but patients with sterile middle ear fluid felt better after 3 to 4 days of treatment than patients in whom middle ear fluid was still culture-positive.     

Dynamics of pneumococcal nasopharyngeal colonization during the first days of antibiotic treatment in pediatric patients

BACKGROUND: Nasopharyngeal (NP) carriage of antibiotic-resistant Streptococcus pneumoniae was shown to be associated with recent antibiotic treatment. To date no studies have evaluated early dynamics of pneumococcal NP carriage during antibiotic treatment. OBJECTIVES: To observe changes in NP pneumococcal carriage within 3 to 4 days after initiation of antibiotic treatment in acute otitis media (AOM). METHODS: Patients ages 3 to 36 months with AOM treated with various antibiotics were prospectively followed. Nasopharyngeal culture for S. pneumoniae was obtained before (Day 1) and 72 to 96 h after initiation of treatment (Days 4 to 5). Antibiogram and serotyping were performed in all isolates as was also the MIC of penicillin. The disappearance and persistence of the initial isolates as well as the appearance of isolates with new serotype or with new antibiotic susceptibility patterns were investigated. RESULTS: A total of 120 patients were studied: 106 received beta-lactam antibiotics and 14 received azithromycin. Among the initial 76 pneumococcal isolates 63, 37 and 13% were resistant to > or =1, > or =2 and > or =3 antibiotic drugs. After 3 to 4 days of treatment with various beta-lactam drugs, 45, 63 and 100% of isolates with MIC values of <0.1 microg/ml, 0.125 to 0.25 microg/ml and 0.38 to 1.0 microg/ml, respectively, persisted in the NP (P = 0.038). There was a difference between the various beta-lactam drugs in their effect on NP colonization: a drug with lower MIC values (cefuroxime-axetil) had a better eradication rate of penicillin-susceptible organisms than a less active one (cefaclor), but neither significantly reduced carriage of penicillin nonsusceptible isolates. Azithromycin eliminated carriage of macrolide-susceptible organisms but increased the carriage of macrolide-resistant ones. In 19 of 120 (16%) patients a new S. pneumoniae isolate was recovered 3 to 4 days after initiation of treatment. Of those 16 (84%) were resistant to the drug the patient was receiving. CONCLUSION: A rapid selection of nonsusceptible NP pneumococcal isolates during antibiotic treatment for AOM is common. This phenomenon may contribute to the spread of resistant pneumococci.     

A new type of cohesin domain that specifically binds the dockerin domain of the Clostridium thermocellum cellulosome-integrating protein CipA

The cellulosome-integrating protein CipA, which serves as a scaffolding protein for the cellulolytic complex produced by Clostridium thermocellum, comprises a COOH-terminal duplicated segment termed the dockerin domain. This paper reports the cloning and sequencing of a gene, termed sdbA (for scaffoldin dockerin binding), encoding a protein which specifically binds the dockerin domain of CipA. The sequenced fragment comprises an open reading frame of 1,893 nucleotides encoding a 631-amino-acid polypeptide, termed SdbA, with a calculated molecular mass of 68,577 kDa. SAA comprises an NH2-terminal leader peptide followed by three distinct regions. The NH2-terminal region is similar to the NH2-terminal repeats of C. thermocellum OlpB and ORF2p. The central region is rich in lysine and harbors a motif present in Streptococcus M proteins. The COOH-terminal region consists of a triplicated sequence present in several bacterial cell surface proteins. The NH2-terminal region of SdbA and a fusion protein carrying the first NH2-terminal repeat of OlpB were shown to bind the dockerin domain of CipA. Thus, a new type of cohesin domain, which is present in one, two, and four copies in SdbA, ORF2p, and OlpB, respectively, can be defined. Since OlpB and most likely SdbA and ORF2p are located in the cell envelope, the three proteins probably participate in anchoring CipA (and the cellulosome) to the cell surface.     

Functions of S-layers

Although S-layers are being increasingly identified on Bacteria and Archaea, it is enigmatic that in most cases S-layer function continues to elude us. In a few instances, S-layers have been shown to be virulence factors on pathogens (e.g. Campylobacter fetus ssp. fetus and Aeromonas salmonicida), protective against Bdellovibrio, a depository for surface-exposed enzymes (e.g. Bacillus stearothermophilus), shape-determining agents (e.g. Thermoproteus tenax) and nucleation factors for fine-grain mineral development (e.g. Synechococcus GL 24). Yet, for the vast majority of S-layered bacteria, the natural function of these crystalline arrays continues to be evasive. The following review up-dates the functional basis of S-layers and describes such diverse topics as the effect of S-layers on the Gram stain, bacteriophage adsorption in lactobacilli, phagocytosis by human polymorphonuclear leukocytes, the adhesion of a high-molecular-mass amylase, outer membrane porosity, and the secretion of extracellular enzymes of Thermoanaerobacterium. In addition, the functional aspect of calcium on the Caulobacter S-layer is explained.