[Correction of ear malformations with autologous rib cartilage]

INTRODUCTION

Ear malformations are mainly isolated deformations but exist also in combination with various syndromes. A visible malformation in cases of microtia is a problem for the entire family. Auricular reconstruction with autologous cartilage has been well established in the last decade. Optimization of the technique has led to improved and reliable results.

OPERATION AND RESULTS

Based on the experience of 120 cases we developed a concept that allows total ear reconstruction in two operative steps. In the first operation autologous rib cartilage is harvested and a natural framework is created following the template from the opposite ear. The ear remnant is transposed and the framework placed in a subcutaneous pocket on the mastoid plane. After a healing period of around 6 weeks the second operation reconstructs the auricular projection and the retroauricular fold.

CONCLUSION

Based on an individualized surgical treatment, auricular reconstruction with autologous rib cartilage are possible from the age of around 8 to the advanced period of life with reproducibly good results.

Comparison of multiple environmental factors for asthmatic children in public housing

Nine families of a public housing development in Boston were enrolled in a pilot asthma intervention program designed to gather dense environmental data and generate hypotheses about the relative importance of different contaminants and the viability of interventions. Despite formidable challenges working with this inner-city population, the project team succeeded in gaining active support for the project by forming a partnership with a community-based organization and by building positive relationships between the field team and the residents. Families were provided with physical interventions such as air filters, industrial cleaning and mattress covers to each apartment. Indoor temperature was high and relative humidity low during winter. Insulation of exposed steam pipes did not lower temperature. Cockroach, mouse and pet antigen levels were variable and frequently high in settled dust. Viable fungal spore levels were variable and high in some apartments. Dust-mite allergen levels were below the level of concern. Industrial cleaning led to transient reduction in mouse and cockroach antigen burden. Mattress and pillow covers lowered dust-mite antigen in bedrooms, but not living rooms. Nitrogen dioxide (NO2) levels exceeded ambient concentrations due to use of gas stoves and concentrations of particulate matter with aerodynamic diameter <2.5 microm (PM2.5) were above ambient levels because of smoking. Air filtering systems did not reduce PM levels. Several volatile organic compounds (VOCs) were above adverse risk concentrations. We hypothesize that our findings are consistent with a multifactorial model for exacerbation of asthma in this population and that no single problem dominates.

The coxBAC operon encodes a cytochrome c oxidase required for heterotrophic growth in the cyanobacterium Anabaena variabilis strain ATCC 29413

Three genes, coxB, coxA, and coxC, found in a clone from a gene library of the cyanobacterium Anabaena variabilis strain ATCC 29413, were identified by hybridization with an oligonucleotide specific for aa(3)-type cytochrome c oxidases. Deletion of these genes from the genome of A. variabilis strain ATCC 29413 FD yielded strain CSW1, which displayed no chemoheterotrophic growth and an impaired cytochrome c oxidase activity. Photoautotrophic growth of CSW1, however, was unchanged, even with dinitrogen as the nitrogen source. A higher cytochrome c oxidase activity was detected in membrane preparations from dinitrogen-grown CSW1 than from nitrate-grown CSW1, but comparable activities of respiratory oxygen uptake were found in the wild type and in CSW1. Our data indicate that the identified cox gene cluster is essential for fructose-dependent growth in the dark, but not for growth on dinitrogen, and that other terminal respiratory oxidases are expressed in this cyanobacterium. Transcription analysis showed that coxBAC constitutes an operon which is expressed from two transcriptional start points. The use of one of them was stimulated by fructose.

Environmental management of asthma at Massachusetts managed care organizations

Asthma management staff at eight Massachusetts managed care organizations (MCOs) were interviewed to learn the extent of inclusion of environmental prevention strategies in their asthma disease management policies. Six of the plans had formal asthma disease management programs, all reported to be based on the National Heart Lung and Blood Institute guidelines, but none followed these guidelines in their entirety. Three MCOs provided for home visits that included addressing environmental factors for severe asthmatics. Despite the limited role that MCOs appear to play in environmental prevention of asthma, the authors identify opportunities and encourage efforts to expand these programs.

The inflammatory action of CD40 ligand (CD154) expressed on activated human platelets is temporally limited by coexpressed CD40

Recently, we have demonstrated that human platelets carry preformed CD40 ligand (CD154) molecules, which rapidly appear on the platelet surface following stimulation by thrombin. Once on the surface, platelet CD154 induces an inflammatory reaction of CD40-bearing endothelial cells. This study shows that strong platelet agonists other than thrombin also lead to the expression of CD154 on the platelet surface. At the same time, several lines of evidence are presented that together indicate that thrombotic events in the vasculature are generally accompanied by activation of the inflammatory potential of platelet CD154. This study also reports the constitutive expression of CD40, the receptor for CD154, on platelets. The binding of CD154 to coexpressed CD40 in the platelet aggregate leads within minutes to hours to the cleavage of membrane-bound surface CD154 and the release of an 18-kd soluble form of the molecule. Soluble CD154 (sCD154), in contrast to transmembrane CD154, can no longer induce an inflammatory reaction of endothelial cells. These findings indicate that the interaction of platelet CD154 with CD40 on neighboring cells is temporally limited to prevent an uncontrolled inflammation at the site of thrombus formation. Thus, similar to the very tight regulation of the CD154-CD40 interaction in the immune system, an effective mechanism controls the inflammatory potential of platelet CD154 in the vascular system. (Blood. 2001;98:1047-1054)

Respiratory diseases in the first year of life in children born to HIV-1-infected women

Our objective was to describe the respiratory complications, clinical findings, and chest radiographic changes in the first year of life in infected and uninfected children born to HIV-1-infected women. We prospectively followed a cohort of 600 infants born to HIV-1-infected women from birth to 12 months in a multicenter study. Of these, 93 infants (15.5%) were HIV-1-infected, 463 were uninfected, and 44 were of unknown status prior to death or loss to follow-up. The cumulative incidence ( +/- SE) of an initial pneumonia episode at 12 months was 24.1 +/- 4.7% in HIV-1-infected children compared to 1.4 +/- 0.6% in HIV-1-uninfected children (P < 0.001). The rate of Pneumocystis carinii pneumonia (PCP) was 9.5 per 100 child-years. The HIV-1 RNA load was not higher in the group that developed pneumonia in the first year vs. those who did not. Children who developed lower respiratory tract infections or PCP had increased rates of decline of CD4 cell counts during the first 6 months of life. Lower maternal CD4 cell counts were associated with higher rates of pneumonia, and upper and lower respiratory tract infections. The rates of upper respiratory tract infection and bronchiolitis/reactive airway disease in infected children were not significantly different than in uninfected children. At 12 months, significantly more HIV-1-infected than uninfected children had tachypnea and chest radiographs with nodular and reticular densities. There was no relationship between cytomegalovirus infection in the first year of life and radiographic changes or occurrences of pneumonia. In conclusion, despite a low incidence of PCP, rates of pneumonia remain high in HIV-infected children in the first year of life. The incidence of pneumonia in uninfected infants born to HIV-1-infected mothers is low. Chest X-ray abnormalities and tachypnea suggest that subacute disease is present in infected infants. Further follow-up is warranted to determine its nature.

Forced expiratory flow in uninfected infants and children born to HIV-infected mothers

The Pediatric Pulmonary and Cardiovascular Complications of Vertically Transmitted HIV (P(2)C(2) HIV) Study is a multicenter study examining pulmonary and cardiac outcomes in offspring of HIV-infected mothers. This portion of the P(2)C(2) study tests the hypothesis that infants exposed to, but uninfected by, maternal HIV have normal maximal expiratory flow at functional residual capacity (V'max,(FRC)). We obtained 500 measurements of V'max,(FRC) by rapid thoracic compression in 285 children ages 6-30 mo in five U.S. centers. The data were compared with those from a healthy cohort of children described elsewhere. V'max,(FRC) rose with height in a linear relationship. The slope of the regression line in the exposed infants did not differ statistically from the slope in the comparison group, but the intercept was about 20% lower (p < 0.001). Height and weight were comparable in the two cohorts, and the differences between intercepts persisted after adjusting for birth weight and gestational age. However, maternal HIV infection cannot be assumed to be the cause as the cohorts may have differed in other variables, such as socioeconomic status and frequency of maternal smoking and drug use. Also, measurements varied substantially within and between our five centers, probably in part because of different racial and ethnic distributions. In summary, maternal HIV infection probably has only a modest effect, if any, on maximal expiratory flow at functional residual capacity in uninfected infants.

Beliefs about diagnosing asthma in young children

OBJECTIVES

To determine what factors primary care pediatricians believe are important in establishing the initial diagnosis of childhood asthma and to identify variations in physicians' beliefs concerning this clinical decision.

STUDY DESIGN

Massachusetts American Academy of Pediatrics Fellows were surveyed about their beliefs concerning the importance of 20 clinical factors associated with establishing the initial diagnosis of asthma.

RESULTS

Most clinicians considered recurrent wheeze (96%), symptomatic improvement with a bronchodilator (90%), recurrent cough (89%), exclusion of alternative diagnoses (87%), and suggestive peak flow findings (82%) as important in diagnosing asthma. However, there was substantial heterogeneity among clinicians as to which combinations of factors they each considered relevant; for example, only 60% identified all 5 of the above factors to be necessary or important. Further, <50% identified presence of any of the 20 factors as necessary. Although national guidelines cite objective assessment of pulmonary function as essential, spirometry and peak expiratory flow testing were identified as necessary by only 8% and 10%, respectively. Two factors believed to contribute to establishing the asthma diagnosis contradicted the National Asthma Education and Prevention Program guidelines and expert opinion (age >2 years and absence of fever during episodes) and these beliefs were more likely held by those clinicians in practice for >5 years.

CONCLUSIONS

The majority of pediatricians believe several common clinical factors establish a diagnosis of childhood asthma, but disagree over what combinations of these factors are important. Some misconceptions persist despite wide dissemination of clinical practice guidelines. We believe that future asthma guidelines will need to organize diagnostic criteria in an easily understood format, like a decision tree, to facilitate early recognition of asthma in young children.

Identification of aquaporin 5 (AQP5) within the cochlea: cDNA cloning and in situ localization

Dysfunction of fluid and electrolyte homeostasis is considered to cause variety of inner ear disorders. One group of candidate proteins that may play a critical role in the inner ear fluid homeostasis is the aquaporins, a family of proteins whose members have well defined roles in fluid transport in variety of organs. This study reports the identification of AQP5, a member of the aquaporin family, within the rat inner ear and its in situ localization. AQP5 was initially identified within rat cochlear RNA via RT-PCR and sequence analysis of the amplified fragments. Immunoblot of cochlear homogenate yielded a predominant AQP5-immunoreactive band of M(r) 35 kDa. The anti-AQP5 immunoreactivity, indicating expression of the AQP5 polypeptide, was localized within the cochlea in situ to the cell types that form the lateral wall of the cochlear duct-the external sulcus (ES) cells and the cells of the spiral prominence. Expression of AQP5 was observed in the apical turn but not the basal turn of the cochlea; nor was it observed in the vestibular neuroepithelia or its supporting cells. The restricted expression of AQP5 to the apical turns of the cochlea suggests its potential role in low frequency hearing.

A telecommunications system to manage patients with chronic disease

The care of patients with chronic disease is a large and growing problem in the United States and other industrialized countries.' it is expensive, and the quality of care received by patients is often sub-optimal, resulting in poor health outcomes. We developed a totally automated computer-controlled telecommunications system, called TLC, that provides--frequent, close monitoring of patients with chronic disease and reports the results to the patients' physicians on a timely basis, so that they can intervene appropriately. TLC also monitors the patients' important self care activities, such as medication-taking, and provides education and counseling to improve the patients' performance of these activities. The system operates through regularly scheduled telephone conversations with patients' in their homes. An evaluation of a TLC chronic disease application for patients with hypertension demonstrated that use of the system was associated with significant improvement of the patients' adherence to their medication regimens and significantly improved blood pressure control. These results show that it is possible to design an information science-based health care delivery system that performs functions usually performed only by health care professionals, and suggests that information science will become an important means of delivering health care services in the next millennium.

An epidemic of burkholderia cepacia transmitted between patients with and without cystic fibrosis

Burkholderia cepacia is an important pathogen in cystic fibrosis (CF) and an infrequent cause of nosocomial infection in non-CF patients. This report describes a large hospital outbreak that appeared to involve both patient groups, a previously unrecognized phenomenon. Ribotype restriction fragment length polymorphism (RFLP) profiles and pulsed-field gel electrophoresis-resolved macrochromosomal RFLPs were analyzed, a ribotype-based phylogenic tree was constructed, and case-control and cohort studies were performed. A single dominant clone was found in both CF and non-CF groups. Phylogenic analysis suggests that it has evolved independently and that such highly transmissible strains can emerge rapidly and randomly. Acquisition risk in the CF patients was linked to hospitalization (odds ratio=5.47, P=.0158, confidence interval=1. 28-26.86) and was associated with significantly increased mortality rates. Infection control policies must now consider this threat of transmission between non-CF and CF patients.

Assembly of adeno-associated virus type 2 capsids in vitro

Capsid proteins VP1, VP2 and VP3 of adeno-associated virus type 2 (AAV-2) were separately expressed by recombinant baculoviruses, purified under denaturing conditions and renatured in the presence of 0.5 M arginine, followed by dialysis against buffers of physiological ionic strength. At a protein concentration of 0.05 mg/ml, the three capsid proteins predominantly formed monomers and, to a lesser extent, oligomers, as determined by sedimentation analysis. Oligomerization increased at higher protein concentrations. The capsid protein oligomers consisted of globular, non-capsid-like structures, as detected by electron microscopy. Addition of a HeLa cell extract significantly stimulated oligomerization of the capsid proteins, probably due to interactions with HeLa cell proteins. Characterization of structures sedimenting around 60S by immunoprecipitation and electron microscopy showed that, in addition to other aggregates, empty capsid-like structures were formed in vitro. The identity of these structures as empty AAV capsids was verified by immunoelectron microscopy. Analysis of capsid formation in HeLa cells by transfection of VP expression constructs allowing separate expression of VP1, VP2 and VP3 showed that they were able to form capsids, although with a reduced efficiency as compared to VP proteins expressed from the wt cap gene. This finding suggests that the mutations introduced to allow separate capsid protein expression reduced the efficiency of capsid assembly in vivo and might also explain the reduced recovery of empty capsids employing the in vitro assembly procedure.

The emergence of a highly transmissible lineage of cbl+ Pseudomonas (Burkholderia) cepacia causing CF centre epidemics in North America and Britain

The rapid increase in Pseudomonas (Burkholderia) cepacia infection in cystic fibrosis (CF) patients suggests epidemic transmission, but the degree of transmissibility remains controversial as conflicting conclusions have been drawn from studies at different CF centres. This report provides the first DNA sequence-based documentation of a divergent evolutionary lineage of P. cepacia associated with CF centre epidemics in North America (Toronto) and Europe (Edinburgh). The involved epidemic clone encoded and expressed novel cable (Cbl) pili that bind to CF mucin. The sequence of the cblA pilin subunit gene carried by the epidemic isolates proved to be invariant. Although it remains to be determined how many distinct, highly transmissible lineages exist, our results provide both a DNA sequence and chromosomal fingerprint that can be used to screen for one such particularly infectious, transatlantic clone.

Transmissibility of Pseudomonas cepacia infection in clinic patients and lung-transplant recipients with cystic fibrosis

BACKGROUND

In patients with cystic fibrosis, infection with Pseudomonas cepacia is associated with poor outcomes. However, the extent of person-to-person transmission and the source of P. cepacia infection after lung transplantation are not well defined. Using DNA-based typing systems, we sought to determine the genetic relatedness of P. cepacia infection at one cystic fibrosis center.

METHODS

We analyzed 65 P. cepacia isolates gathered over a period of eight years at a single cystic fibrosis center from 17 clinic patients and from 5 patients who underwent double-lung transplantation. The isolates were analyzed by ribotyping and chromosomal fingerprinting based on pulsed-field gel electrophoresis.

RESULTS

Analyses of serial isolates revealed that each clinic patient and transplant recipient harbored a different P. cepacia clone that was persistent. In the transplant recipients, the preoperative and postoperative isolates were identical. In the two patients with disseminated infection after lung transplantation, isolates from multiple sites were identical and indicated clonal expansion of the previous respiratory P. cepacia strain. Pulsed-field gel electrophoresis proved both more discriminative and more practical than ribotyping as a means of defining the genetic relatedness of the P. cepacia isolates.

CONCLUSIONS

Our serial analyses in patients with cystic fibrosis at one center found distinct strains of P. cepacia persistently infecting each patient and no evidence of person-to-person transmission of this organism. P. cepacia infection after lung transplantation was due to the persistence of the strain present before transplantation.

Conservation of the gene for outer membrane protein OprF in the family Pseudomonadaceae: sequence of the Pseudomonas syringae oprF gene

The conservation of the oprF gene for the major outer membrane protein OprF was determined by restriction mapping and Southern blot hybridization with the Pseudomonas aeruginosa oprF gene as a probe. The restriction map was highly conserved among 16 of the 17 serotype strains and 42 clinical isolates of P. aeruginosa. Only the serotype 12 isolate and one clinical isolate showed small differences in restriction pattern. Southern probing of PstI chromosomal digests of 14 species from the family Pseudomonadaceae revealed that only the nine members of rRNA homology group I hybridized with the oprF gene. To reveal the actual extent of homology, the oprF gene and its product were characterized in Pseudomonas syringae. Nine strains of P. syringae from seven different pathovars hybridized with the P. aeruginosa gene to produce five different but related restriction maps. All produced an OprF protein in their outer membranes with the same apparent molecular weight as that of P.aeruginosa OprF. In each case the protein reacted with monoclonal antibody MA4-10 and was similarly heat and 2-mercaptoethanol modifiable. The purified OprF protein of the type strain P. syringae pv. syringae ATCC 19310 reconstituted small channels in lipid bilayer membranes. The oprF gene from this latter strain was cloned and sequenced. Despite the low level of DNA hybridization between P. aeruginosa and P. syringae DNA, the OprF gene was highly conserved between the species with 72% DNA sequence identity and 68% amino acid sequence identity overall. The carboxy terminus-encoding region of P. syringae oprF showed 85 and 33% identity, respectively, with the same regions of the P. aeruginosa oprF and Escherichia coli ompA genes.

Restriction fragment length polymorphisms among uropathogenic Escherichia coli isolates: pap-related sequences compared with rrn operons

Among the adhesin-encoding virulence operons associated with uropathogenic Escherichia coli, only pap (pyelonephritis-associated pilus)-related gene clusters typically exhibit variation in their structure and chromosomal copy number. To access further such variability, we compared pap restriction fragment length polymorphisms (RFLPs) with those detected among rRNA (rrn) operons, which encode an essential host function unrelated to virulence. To place such findings in a phylogenetic perspective, the E. coli isolates were also characterized by using multilocus enzyme electrophoresis. Variation in the rrn RFLP profiles correlated with evolutionary divergence resolved by multilocus enzyme electrophoresis; isolates with identical rrn profiles represented the same or closely related electrophoretic types. In contrast, such isolates frequently had different pap-related RFLPs, indicating that these genetic variations have developed recently relative to the changes associated with essential rrn operons or metabolic enzymes. Despite such fluctuations, two lines of evidence indicate conditions under which the pap-related RFLPs can be stably maintained. First, for each of 20 patients with urosepsis, both the primary urinary tract isolate and the concurrent blood isolate were identical. Second, although obtained from different patients, some isolates representing the same electrophoretic type also had identical pap-related RFLPs. Thus, the genotypic diversity of this virulence adhesin operon was not generated during the course of acute infection or during laboratory manipulations. Since fecal E. coli isolates frequently carry chromosomally encoded pap-related gene clusters, these findings suggest that the intra- and interchromosomal recombination events generating the polymorphisms associated with the pap-related sequences likely occur among the E. coli of the commensal reservoir.

Molecular epidemiology of adhesin and hemolysin virulence factors among uropathogenic Escherichia coli

The pap, prs, pil, and hly operons of the pyelonephritic Escherichia coli isolate J96 code for the expression of P, F, and type 1 adhesins and the production of hemolysin, respectively; the afaI operon of the pyelonephritic E. coli KS52 encodes an X adhesin. Using different segments of these operons as probes, colony hybridizations were performed on 97 E. coli urinary tract and 40 fecal clinical isolates to determine (i) the presence in the infecting bacteria of nucleotide sequences related to virulence operons, and (ii) the phenotypic properties associated with such sequences. Coexpression of P and F adhesins encoded by pap-related sequences was detected more frequently among isolates from patients with pyelonephritis (32 of 49, 65%) than among those with cystitis (11 of 48, 23%; P less than 0.0001) or from fecal specimens (6 of 40, 15%; P less than 0.0001). Therefore, the expression of both adhesins appears to be critical in the colonization of the upper urinary tract. In contrast, afaI-related sequences were detected significantly more frequently among isolates from patients with cystitis, suggesting that this class of X adhesin may have a role in lower urinary tract infections. Urinary tract isolates differed from fecal isolates by a low incidence of type 1 adhesin expression among pil probe-positive isolates. hly-related sequences were only detected in pap probe-positive isolates. The frequency of hemolysin production among pap probe-positive isolates was not associated with a particular pattern of infection. The distribution of these virulence factors was similar in the presence or absence of reflux, indicating that structural abnormalities of the urinary tract did not facilitate colonization by adhesin-negative isolates.

Structure and copy number of gene clusters related to the pap P-adhesin operon of uropathogenic Escherichia coli

The structurally related pap and prs operons of the uropathogenic Escherichia coli isolate J96 encode a P and an F adhesin that mediate bacterial attachment to the human P blood group antigen and the Forssman antigen, respectively. Using probes prepared from different segments of the pap operon, Southern blot hybridizations were performed to characterize pap-related sequences of 30 E. coli clinical isolates expressing different adhesin phenotypes. Gene clusters encoding P and F adhesins displayed no restriction site polymorphism in sequences homologous to the papH, papC, and papD genes that encode proteins essential to the transport and polymerization of the subunits of the P-pilus adhesin. In contrast, pap-related genetic elements associated with a null phenotype either lacked homology to the papH, papC, and papD genes or displayed a restriction site polymorphism in this region. Sequences within and surrounding the J96 papG and prsG adhesin genes that determine the binding specificities to the P and F antigens, respectively, were not conserved. However, gene clusters encoding different binding specificities could not be distinguished based on such restriction site polymorphisms. The majority of clinical isolates had more than one copy of pap-related sequences that involved gene clusters similar to the J96 pap operon, as well as genetic elements that were related only to a part of this operon. The implications of this unexpected copy number polymorphism with respect to possible recombination events involving pap-related sequences are discussed.

Functionally distinct monoclonal antibodies reactive with enzymatically active and binding domains of Pseudomonas aeruginosa toxin A

Monoclonal antibodies (MAbs) are described which react with two discrete structural domains of Pseudomonas aeruginosa toxin A and which have two distinct functional profiles. The MAbs designated T3-1C7 and T4-1F2 reacted with a 46,000-dalton peptide similar to the putative B or binding fragment of toxin A. These antibodies neutralized the cytotoxic and lethal properties of toxin but had no effect on its ADP-ribosyl transferase activity. T4-1F2 interfered with the binding of toxin A to membrane receptors on mouse fibroblasts (L cells), although the epitope for the antibody appears to be distinct from the actual receptor binding site. The MAb designated T2-1H2 reacted with intact toxin A and with a cloned, enzymatically active carboxy-terminal polypeptide similar to the toxin A fragment. This MAb neutralized the ADP-ribosyl transferase activity of activated holotoxin and of the cloned peptide, but inhibited neither binding of toxin to membrane receptors nor its cytotoxic and lethal actions. The complementary specificity and function of these MAbs confirm the functional specialization of discrete structural domains within the toxin A molecule. Our findings suggest the greater antitoxic potential of antibodies that block binding, compared with those which inhibit the enzymatic activity of toxin A.