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Structured Abstract Authors – Shen K, Krakora SM, Cunningham M, Singh M, Wang X, Hu FZ, Post JC, Ehrlich GD Introduction – The mechanisms underlying craniosynostosis remains unknown. However, mutations in FGFR2 are associated with craniosynostotic syndromes. We previously compared gene expression patterns of patent and synostosing coronal sutures in the nude rat and demonstrated down regulation of Noggin in synostosing sutures. Noggin expression is also suppressed by FGF2 and constitutive FGFR2 signaling [ Warren et al. (2003) Nature, vol. 422, pp. 625–9; McMahon et al. (1998) Genes Dev, vol. 12, pp. 1438–52 ]. Thus, we therefore hypothesized that the addition of rhNoggin to prematurely fusing sutures should prevent synostosis. Materials and Methods – Cohorts of nude rats were subjected to: 1) surgical elevation of the coronal suture (shams); 2) surgical elevation and placement of normal or FGFR2 mutant human osteoblasts onto the underlying dura (xenotransplants); or 3) xenotransplantation with co-application of heparin acrylic beads soaked with recombinant human (rh) Noggin. Eleven days post-surgery the sutures were harvested, stained, and histologically examined. Results – Animals that received control osteoblasts, sham surgery, or no surgery demonstrated normal skull growth and coronal suture histology, whereas animals transplanted only with FGFR2 mutant osteoblasts showed evidence of bridging synostosis on the calvarial dural surface. Sutures treated with FGFR2 mutant osteoblasts and rhNoggin remained patent. Conclusion – The chimeric nude rate model is a viable model of craniosynostosis. FGFR2 mutations in osteoblasts induce bridging osteosynthesis demonstrating one of the mechanisms for premature suture fusion. Topical application of rhNoggin protein prevents craniosynostosis in the weanling nude rat xenotransplantation model of syndromic craniosynostosis. [ABSTRACT FROM AUTHOR]

Context: Gastroesophageal reflux (GER) has not previously been widely regarded as a hereditary disease. A few reports have suggested, however, that a genetic component may contribute to the incidence of GER, especially in its severe or chronic forms.Objective: To identify a genetic locus that cosegregates with a severe pediatric GER phenotype in families with multiple affected members.Design: A genome-wide scan of families affected by severe pediatric GER using polymorphic microsatellite markers spaced at an average of 8 centimorgans (cM), followed by haplotyping and by pairwise and multipoint linkage analyses.Setting: General US community, with research performed in a university tertiary care hospital.Subjects: Affected and unaffected family members from 5 families having multiple individuals affected by severe pediatric GER, identified through a patient support group.Main Outcome Measures: Determination of inheritance patterns and linkage of a genetic locus with the severe pediatric GER phenotype by logarithm-of-odds (lod) score analysis, considering a lod score of 3 or greater as evidence of linkage.Results: In these families, severe pediatric GER followed an autosomal dominant hereditary pattern with high penetrance. A gene for severe pediatric GER was mapped to a 13-cM region on chromosome 13q between microsatellite markers D13S171 and D13S263. A maximum multifamily 2-point lod score of 5.58 and a maximum multifamily multipoint lod score of 7.15 were obtained for marker D13S1253 at map position 35 cM when presumptively affected persons were modeled as unknown (a maximum multipoint score of 4.88 was obtained when presumptively affected persons were modeled as unaffected).Conclusion: These data suggest that a gene for severe pediatric GER maps to chromosome 13q14. JAMA. 2000;284:325-334 [ABSTRACT FROM AUTHOR]

Context: Otitis media with effusion (OME) can lead to significant hearing loss in children. Although previous studies have shown that bacterial DNA is present in a significant percentage of effusions sterile by culture, whether the DNA represents viable organisms or "fossilized remains" is unknown.Objective: To determine if bacterial messenger RNA (mRNA), as detected by a reverse transcriptase-polymerase chain reaction (RT-PCR)-based assay, is present in chronic pediatric middle ear effusions that contain bacterial DNA but are sterile by standard cultural methods. Bacterial mRNAs have a half-life measured in seconds to minutes; therefore, detection of bacteria-specific mRNAs would be evidence that metabolically active organisms are present.Design: Blinded comparative study.Patients: A total of 93 effusions from pediatric outpatients seen for myringotomy and tube placement for chronic (>3 months) OME (median age of children, 17 months).Setting: Tertiary care pediatric hospital.Main Outcome Measures: Percentage of positive test results for RT-PCR-based assays compared with culture for Haemophilus influenzae and concordance between RT-PCR and PCR-based findings for bacterial nucleic acids.Results: Eleven (11.8%) of the 93 specimens tested positive by culture, PCR, and RT-PCR for H influenzae. A total of 29 specimens (31.2%) were positive by PCR but negative by culture for H influenzae. All 29 specimens were positive by RT-PCR for H influenzae-specific mRNA.Conclusions: The RT-PCR-based assay system can detect the presence of bacterial mRNA in a significant percentage of culturally sterile middle ear effusions, establishing the presence of viable, metabolically active, intact organisms in some culture-negative OME. [ABSTRACT FROM AUTHOR]

Children with recurrent respiratory papillomatosis vary greatly in their clinical disease course. Many have mild disease with eventual remission while others present with an early aggressive airway obstructive course. This study consisted of 24 pediatric patients whose specimens underwent polymerase chain reaction analysis for cytomegalovirus (CMV), herpes simplex virus (HSV), and human papillomavirus (HPV) type. Nineteen of 24 specimens contained enough DNA for this study. None of the specimens were found to contain DNA from HPV-16, -18, -31, -33; CMV; or HSV, which contrasts with our previous findings in adults. Ten patients were infected by HPV-11 and seven of these underwent tracheotomy because of an aggressive tumorigenic clinical course. Nine patients were infected by HPV-6 alone of whom only two required a tracheotomy (P = 0.05, Fisher's Exact Test). The early airway obstructive course associated with HPV-11, however, had no bearing on achieving eventual disease remission, with decannulation achieved in eight of nine children. [ABSTRACT FROM AUTHOR]

Discusses the impact of the polymerase chain reaction (PCR) in clinical medicine since 1983. How the enzymatic in vitro DNA amplification method works; Function of PCR in the detection of infectious diseases and mutations associated with genetic diseases; Applications of PCR to the human genome which includes cancer diagnosis and forensic medicine; Limitations of PCR which include difficulty with large segments of DNA.

Objective: Multiple sclerosis (MS) is a disabling idiopathic inflammatory disorder with evidence of immune dysfunction. Current therapies for MS include preparations of beta-interferon (beta IFN). We studied the gene expression patterns in peripheral blood mononuclear cells from relapsing-remitting MS patients undergoing weekly beta IFN-1a therapy (Avonex; 30 mg intramuscular) to identify biomarkers for beta IFN responsiveness., Methods: Oligonucleotide microarrays were used for the comparative analysis of gene expression patterns from longitudinal PBMC samples taken from five patients undergoing beta IFN therapy., Results: On the basis of two-fold changes in expression levels and statistical analyses we selected a candidate diagnostic set of 136 genes that were differentially expressed between pretreatment and IFN-beta-1a-treated MS patients. When we applied this gene set to cluster the specimens according to their expression profiles, the pretreatment samples clustered in one branch, and acute and chronic samples following treatment clustered in another branch. However, the chronic samples from the single clinical non-responder clustered with the pretreatment branch, suggesting that a possible reversal of beta IFN-induced gene expression may be contributing to the poor clinical response., Conclusions: These 136 genes represent potential targets for new MS therapeutics and the basis for lack of beta IFN response.

Objectives/hypothesis: Bacteriologic studies of otitis media with effusion (OME) using highly sensitive techniques of molecular biology such as the polymerase chain reaction have demonstrated that traditional culturing methods are inadequate to detect many viable bacteria present in OME. The presence of pathogens attached to the middle-ear mucosa as a bacterial biofilm, rather than as free-floating organisms in a middle-ear effusion, has previously been suggested to explain these observations. The suggestion has been speculative, however, because no visual evidence of such biofilms on middle-ear mucosa has heretofore been collected. The hypotheses motivating the current study were: 1) biofilms of nontypable Hemophilus influenzae will form on the middle-ear mucosa of chinchillas in an experimental model of OME, 2) these biofilms will exhibit changes in density or structure over time, and 3) biofilms are also present on tympanostomy tubes in children with refractory post-tympanostomy otorrhea. The objective of this study was to collect visual evidence of the formation of bacterial biofilms in these situations., Study Design: Laboratory study of bacteriology in an animal model and on medical devices removed from pediatric patients., Methods: Experimental otitis media was induced in chinchillas by transbullar injection of nontypable H. influenzae. Animals were killed in a time series and the surface of the middle-ear mucosa was examined by scanning electron microscopy (SEM) for the presence of bacterial biofilms. Adult and fetal chinchilla uninfected controls were similarly examined for comparison. In addition, tympanostomy tubes that had been placed in children's ears to treat OME and removed after onset of refractory otorrhea or other problems were examined by SEM and by confocal scanning laser microscopy for bacterial biofilms, and compared with unused control tubes., Results: Bacterial biofilms were visually detected by SEM on the middle-ear mucosa of multiple chinchillas in which H. influenzae otitis media had been induced. Qualitative evaluation indicated that the density and thickness of the biofilm might increase until at least 96 hours after injection. The appearance of the middle-ear mucosa of experimental animals contrasted with that of uninjected control animals. Robust bacterial biofilms were also visually detected on tympanostomy tubes removed from children's ears for clinical reasons, in contrast with unused control tubes., Conclusions: Bacterial biofilms form on the middle-ear mucosa of chinchillas in experimentally induced H. influenzae otitis media and can form on tympanostomy tubes placed in children's ears. Such biofilms can be directly observed by microscopy. These results reinforce the hypothesis that the bacterial aggregates called biofilms, resistant to treatment by antibiotics and to detection by standard culture techniques, may play a major etiologic role in OME and in one of its frequent complications, post-tympanostomy otorrhea.

Our objective in this study was to determine whether mutations in the gene for the 5-hydroxytryptamine receptor 2A (HTR2A) cause the autosomal dominant form of severe pediatric gastroesophageal reflux (GER), which we had previously mapped to a 21-cM region at chromosome 13q14. Direct sequencing of the HTR2A gene was carried out on DNA from affected and unaffected members of families with severe pediatric GER displaying genetic linkage to the HTR2A locus. In addition, we performed high-resolution linkage mapping within the GER gene region using additional polymorphic markers closely linked to HTR2A. Several previously reported polymorphisms in the HTR2A gene were identified in three families affected with GER. In addition, we identified a novel polymorphism at nucleotide -1273 in the HTR2A promoter. No mutant allele cosegregated exclusively with the GER phenotype in any family. Linkage analysis using additional polymorphic markers narrowed the region of the GER gene to a 9 cM interval between markers D13S263 and CAGR1, formally excluding HTR2A as a candidate gene. In conclusion, sequence analysis of HTR2A and linkage analysis argue against mutations in HTR2A being a cause of severe pediatric GER.

Objective: To measure the impact of tonsillectomy and adenoidectomy (T&A) on children's behavioral and emotional problems using a standardized assessment., Design: Prospective study., Setting: Tertiary care children's hospital., Patients: Thirty-six children, aged 2 through 18 years, with symptoms of nighttime snoring, observed apneas, and daytime mouth breathing and physical examination results demonstrating 3+ or 4+ tonsils scheduled for T&A., Intervention: Parents completed a standard survey of their children's symptoms of sleep apnea and a standardized measure of children's competencies and problems, the Child Behavior Checklist for ages 2 through 3 years or 4 through 18 years, before T&A and 3 months postoperatively., Main Outcome Measure: The Child Behavior Checklist total problem score., Results: The preoperative Child Behavior Checklist total problem score was consistent with abnormal behavior for 10 children (28%). After T&A (n = 15), only 2 scores were abnormal, but the change was not statistically significant. In contrast, the mean total problem score was 7.5 points lower after surgery (95% confidence interval, 5.1-9.7), indicating a significant decrease (P<.001, matched t test)., Conclusions: This pilot study demonstrates a high prevalence (28%) of abnormal behavior in children undergoing T&A for chronic upper airway obstruction. Scores on a standardized measure of behavior improve following T&A, but larger studies with increased statistical power are needed to clarify the degree of improvement and its clinical importance.

Objective: To review the effectiveness of a perioperative management protocol and our experience with a large population of patients with von Willebrand disease (vWD) who require adenotonsillar surgery (T&A)., Design: A retrospective review of the medical records of all patients having the diagnosis of vWD who underwent T&A between January 1, 1992, and July 31, 1996., Setting: A tertiary care, university-based children's hospital., Interventions: Patients having a preoperative diagnosis of vWD received a single intravenous dose of desmopressin acetate, 0.3 pg/kg, approximately 20 minutes before the induction of anesthesia. Beginning January 15, 1994, a standard management protocol involving the postoperative administration of fluids and electrolytes was followed., Main Outcome Measures: Operative blood loss and the incidence of postoperative bleeding and of hyponatremia., Results: Of approximately 4800 patients who underwent T&A during the study period, 69 patients had a diagnosis of vWD. All 67 patients identified preoperatively received desmopressin; 2 were identified by postoperative workup as a result of excessive surgical bleeding. Minimal immediate postoperative bleeding was noted in 7 patients (10%), but none required intervention. Delayed bleeding occurred in 9 patients (13%); all were readmitted to the hospital for observation, 4 (6%) requiring operative cauterization. Substantial postoperative hyponatremia occurred in 3 patients, and 1 patient had seizure activity. Symptomatic hyponatremia has been avoided since a protocol of fluid and electrolyte administration was instituted., Conclusions: Although T&A can be performed safely in patients with vWD, it is not without an increased risk of postoperative hemorrhage. The administration of desmopressin has been reported to reduce the risk of bleeding, but it is not without risk. A protocol for fluid and electrolyte management is recommended.

The human fibroblast growth factor receptor (FGFR) genes play important roles in normal vertebrate development. Mutations in the human FGFR2 gene have been associated with many craniosynostotic syndromes and malformations, including Crouzon, Pfeiffer, Apert, Jackson-Weiss, Beare-Stevenson cutis gyrata, and Antley-Bixler syndromes, and Kleeblaatschadel (cloverleaf skull) deformity. The mutations identified to date are concentrated in the previously characterized region of FGFR2 that codes for the extracellular IgIII domain of the receptor protein. The search for mutations in other regions of the gene, however, has been hindered by lack of knowledge of the genomic structure. Using a combination of genomic library screening, long-range PCR, and genomic walking, we have characterized the genomic structure of nearly the entire human FGFR2 gene, including a delineation of the organization and size of all introns and exons and determination of the DNA sequences at the intron/exon boundaries. Comparative analysis of the human FGFR gene family reveals that the genomic organization of the FGFRs is relatively conserved. Moreover, alignment of the amino acid sequences shows that the four corresponding proteins share 46% identity overall, with up to 70% identity between individual pairs of FGFR proteins. However, the FGFR2 gene contains an additional exon not found in other members of the family, and it also has much larger intronic sequences throughout the gene. Remarkable similarities in genomic organization, intron/exon boundaries, and intron sizes are found between the human and mouse FGFR2 genes. Knowledge gained from this study of the human FGFR2 gene structure may prove useful in future screening studies designed to find additional mutations associated with craniosynostotic syndromes, and in understanding the molecular and cell biology of this receptor family.

The presence of endotoxin (detected by the Limulus amebocyte lysate assay) was compared to the presence of viable Haemophilus influenzae and Moraxella catarrhalis (detected by PCR) in 106 middle-ear effusions from pediatric patients with chronic otitis media. Endotoxin was found in 81 of the 106 specimens. Of these 81 specimens, 66 (81.5%) also tested positive for one or both of the gram-negative bacteria H. influenzae and M. catarrhalis. The data suggest that viable gram-negative bacteria, detectable by PCR but often undetectable by culture, may be the source of endotoxin in middle-ear effusions.

Moraxella (Branhamella) catarrhalis, a causative agent of otitis media, sinusitis, and exacerbation of bronchitis, has acquired widespread ability to produce beta-lactamase and can be nosocomially transmitted. The typing methods used in epidemiological analyses of M. catarrhalis are not optimal for genetic analyses. Two methods, a multiple-locus Southern blot (SB) method and a single-locus PCR-restriction fragment length polymorphism (RFLP) method, were developed and used to assess genetic diversity and potential clinical and geographic relationships in M. catarrhalis. Nine randomly cloned M. catarrhalis DNA fragments were used as probes of SBs containing DNA from 54 geographically and clinically diverse strains. For comparison, a PCR-RFLP method was developed as a quick, inexpensive, and discriminating alternative. A highly variable 3.7-kb genomic region (M46) was cloned and sequenced, and 3.5 kb of the cloned DNA was targeted for PCR amplification. DNAs from the 54 strains were subjected to PCR-RFLP. SB analysis distinguished all strains that had no apparent epidemiological linkage (40 of 54), and PCR-RFLP distinguished fewer strains (21 of 54). Epidemiologically linked strains appeared genetically identical by both methods. PCR-RFLP was compared to pulsed-field gel electrophoresis (PFGE) for 8 of the 54 strains and 23 additional strains. PCR-RFLP distinguished fewer strains than PFGE typing (16 of 31 versus 20 of 31 strains), but PCR-RFLP was more useful for inferring interstrain relatedness. Separate cluster analyses of multilocus SB and single locus PCR-RFLP data showed high genetic diversity within and across geographic locations and clinical presentations. The resultant dendrograms were not entirely concordant, but both methods often gave similar strain clusters at the terminal branches. High genetic diversity, nonconcordance of cluster analyses from different genetic loci, and shared genotypes among epidemiologically linked strains support a hypothesis of high recombination relative to spread of clones. Single-locus PCR-RFLP may be suitable for short-term epidemiological studies, but the SB data demonstrate that greater strain discrimination may be obtained by sampling variation at multiple genomic sites.

This study was designed to determine the persistence of culturable bacteria versus DNA in the presence of a middle ear effusion in a chinchilla model of otitis media. Cohorts of animals were either infected with an ampicillin-resistant Haemophilus influenzae strain or injected with a tripartite inoculum consisting of freeze-thawed Streptococcus pneumoniae; pasteurized Moraxella catarrhalis; and DNA from H influenzae. The H influenzae-infected animals displayed culture positivity and polymerase chain reaction positivity through day 35. In the chinchillas infected with the low-copy number inocula of S pneumoniae, DNA was not detectable after day 1 from the co-inoculated pasteurized M catarrhalis bacteria or the purified H influenzae DNA; however, amplifiable DNA from the live low-copy number bacteria persisted through day 21 even though they were not culture-positive past day 3. These results demonstrate that DNA, and DNA from intact but nonviable bacteria, does not persist in an amplifiable form for more than a day in the presence of an effusion; however, live bacteria, while not culturable, persist in a viable state for weeks.

Multiplex PCR analyses for both bacterial and viral pathogens were conducted in a blinded manner on 33 archival specimens, of known culture status, procured from chinchilla models of both single- and mixed-pathogen-induced otitis media and from a pediatric patient. These specimens had been maintained at -70 degrees C for up to 6 years. Experimental specimens evaluated included middle-ear effusions, nasopharyngeal lavage fluids and middle-ear lavage fluids from animals which were immunologically naive, sham-immunized or actively immunized with nontypeable Haemophilus influenzae antigens. Sampling times used ranged from the day of bacterial or viral challenge to 42 days after challenge. Initial PCR analyses of the 33 specimens matched the traditional culture data in 24 instances (73%), correctly identifying nontypeable H. influenzae, Moraxella catarrhalis, Streptococcus pneumoniae, or adenovirus as the causative agent. A PCR-positive signal for the microbe(s) inoculated was also obtained in four animal model specimens (12%) which were culture negative. One of two culture-negative human effusions was also PCR positive. Thus, overall, results obtained by blinded PCR were 85% concordant with traditional culture methods or correctly indicated the specific pathogen introduced in four specimens that were sterile. In no instance was a false-positive signal obtained for any of the five etiologic agents being evaluated. We conclude that the multiplex PCR analyses are rapid and accurate methodologies when they are used to retrospectively evaluate diverse archival specimens of limited volume from experimental models of otitis media.

Objective: To compare the postoperative course and complications after tonsillectomy or tonsillectomy and adenoidectomy in children with Down syndrome (group 1) with the postoperative course and complications in children in a control group (group 2)., Design: Retrospective review of medical records for the period January 1, 1986, through March 30, 1996., Setting: Tertiary care children's hospital., Patients: The study included 87 children in group 1 and 64 children in group 2 matched for age, sex, and year of surgery., Intervention: Tonsillectomy and adenoidectomy (group 1, 79 children; group 2, 57 children) and tonsillectomy (group 1, 8 children; group 2, 7 children)., Main Outcome Measures: Length of hospitalization and postoperative complications., Results: The length of hospitalization was significantly increased for the children in group 1 compared with that of children in group 2 (1.6 vs 0.80 days; P=.001, Mann-Whitney U test). Twenty-two children (25%) in group 1 required airway management or observation in the pediatric intensive care unit compared with no children in group 2 who required such care (P<.001, Fisher exact test). None of the children in either group required reintubation, continuous positive airway pressure, or tracheotomy. Respiratory complications requiring intervention were 5 times more likely in group 1 (22 [25%] vs 3 [5%]; P<.001, Fisher exact test). The median time until intake of clear liquids and duration of intravenous therapy were significantly increased in group 1 compared with group 2 (5.0 vs 4.0 hours, P=.03; 23.5 vs 16.0 hours, P=.001, respectively; Mann-Whitney U test)., Conclusions: Although tonsillectomy and adenoidectomy can be performed safely in children with Down syndrome, the rate of postoperative respiratory complications is higher and the duration until adequate oral intake is resumed is longer. We therefore recommend that children with Down syndrome be admitted to the hospital overnight after undergoing tonsillectomy and adenoidectomy.

Recent studies using the polymerase chain reaction (PCR) have identified bacterial and viral genomic sequences in culture-negative pediatric middle ear effusions. To evaluate this technique in adults, 19 effusions were analyzed to compare bacterial and viral culture and PCR detection of Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis, and adenovirus. Effusions from 4 subjects positive for human immunodeficiency virus (HIV) were analyzed by PCR for HIV virus. Three of 19 effusions were culture-positive for bacteria, and 0 of 19 for viruses. Fifteen of 19 effusions were PCR-positive for bacterial genomic sequences, and 0 of 19 for adenovirus. Thirteen of 15 PCR-positive specimens demonstrated S pneumoniae, 5 of 15 H influenzae, and 0 of 13 M catarrhalis. All 4 effusions from HIV-positive subjects were PCR-positive for HIV. No effusion was culture-positive and PCR-negative. These results confirm that culture-negative middle ear effusions contain genomic sequences from bacterial pathogens. Finding of HIV RNA and DNA in effusion from HIV-positives suggests replicating virus in this fluid.

Direct visualization of coronary artery bypass grafts can be obtained non-invasively by magnetic resonance imaging. Several studies demonstrated a high sensitivity and somewhat lower specificity for detection of vein-graft patency, using the conventional spin-echo and gradient-echo techniques. In addition, the true functional status can be assessed by determining the flowrate within the graft using phase velocity mapping. Important limitations of the previously applied techniques include the inability to accurately evaluate the different segments of jump grafts and the presence of graft stenoses. Further improvement is to be expected from the recent introduction of breath-hold imaging sequences and the forthcoming introduction of bloodpool-avid contrast agents.

Munchausen syndrome by proxy (MSBP) is a form of child abuse in which a parent or caretaker produces or simulates illness in a child. Often great lengths are undertaken to diagnose and treat the myriad of symptoms and problems in these children. Unnecessary examinations, treatments, and hospitalizations ensure. Unfortunately, some victims of this syndrome die. Munchausen syndrome by proxy is a form of child abuse and should be reported appropriately. The diagnosis of MSBP is difficult to make and must be done with caution as the implications for those involved are serious. Therefore, care must be taken in properly identifying cases. We present a case of MSBP complicating the postoperative course of a boy after undergoing ear surgery for cholesteatoma. Characteristics and potential clues to the diagnosis of MSBP are discussed. The goal of our article is to inform otolaryngologists of this syndrome so they may develop a high index of suspicion to better detect its occurrence.

Objective: MR coronary angiography is most often performed using two-dimensional techniques. Although three-dimensional (3D) acquisitions do have important advantages, they take too long for a single breath-hold and are thus susceptible to respiratory motion artifacts. The purpose of this study was to investigate the accuracy of a unique respiratory-gated 3D MR angiographic technique in identifying the proximal coronary arteries in patients suspected of having coronary artery disease. In addition, we investigated the capability of this technique to detect proximal stenoses., Subjects and Methods: We performed a prospective blinded study in 20 patients who were referred for conventional coronary angiography. A cardiac-gated 3D gradient-echo sequence with fat suppression was used. Retrospective respiratory gating was performed using navigator echoes of the diaphragm position. Using multiplanar reformatting, two independent readers blindly analyzed the data sets for visualization of major coronary arteries, lengths of imaged segments, and detection of significant stenoses (> 50% occlusion of the luminal diameter by conventional angiography)., Results: Seventy-seven of 80 (96%) coronary arteries were positively identified. In one patient, an anomalous coronary anatomy was readily identified and confirmed by conventional angiography. The average lengths of the imaged segments of the right, left main, left anterior descending, and left circumflex coronary arteries were 58 +/- 13 mm, 9 +/- 5 mm, 59 +/- 16 mm, and 24 +/- 10 mm, respectively. Overall sensitivity for the detection of stenoses was low (38%), with a specificity of 95%. Interobserver agreement was 0.92, with a kappa value of 0.65., Conclusion: Respiratory-gated 3D MR angiography allows accurate identification of proximal coronary arteries and may be valuable for 3D imaging of coronary anomalies. Further technical improvements are required to enhance the value of the technique in detecting stenoses.

Background & Aims: Hereditary pancreatitis (HP) is an autosomal-dominant disorder with incomplete penetrance characterized by recurrent bouts of severe epigastric pain with onset usually at 5-10 years of age. A genetic linkage study was designed to identify the HP gene., Methods: A 500-member pedigree was constructed from a U.S. kindred centered in eastern Kentucky and western Virginia. A genome-wide search strategy was employed using a 36-member subset of this family to determine the genetic locus for HP. Testing for linkage to microsatellite loci was performed at 20-cM intervals., Results: Linkage was established between the HP phenotype and chromosome 7q in this subset of the family. Modeled as an autosomal dominant disorder with 80% penetrance, a maximal multipoint logarithm of the odds score of 4.3 was obtained using a four-point analysis consisting of markers D7S684, D7S661, D7S505, and the HP locus. Two microsatellite markers, D7S661 and D7S505, that correspond to the 7q35 region of chromosome 7 spanning a 6-cM region did not evidence obligate recombinations with HP. The centromeric and telomeric limits are defined by recombinations at D7S684 and D7S483, respectively, which generates a 19-cM locus for HP. Utilizing family members from the extended pedigree, a break in the high-risk haplotype between D7S684 and D7S661 was observed, which suggests it may be possible to exclude an additional 8 cM from the HP locus. A maximal pairwise logarithm of the odds score of 4.73 at a recombination fraction of theta at D7S684 was obtained with the addition of these extended family members., Conclusions: Linkage of HP to 7q35 represents a major advancement in our understanding of the genetic basis of this disorder.

Without use of ionizing radiation and injection of contrast material magnetic resonance imaging (MRI) can be applied to generate signal from flowing blood and create tomographic images of the bloodstream in coronary arteries, which resemble conventional contrast enhanced X-ray angiograms. The tortuosity, small diameter and motion of the coronary arteries provided technically demanding problems, which had to be solved before MR coronary angiography became realistic. Faster pulse sequences, dedicated radiofrequency receiver coils, cardiac and respiratory gating techniques were introduced and are still in the process of constant development to improve the quality of the images. To date, most clinical experience has been obtained using 2D approaches necessitating repetitive breath-holds to encompass the coronary artery tree. A substantial part of the proximal and middle parts of the coronary arteries can be visualized, which has proven to be accurate in identifying anomalous coronary anatomy and patency of proximal coronary artery bypass grafts. However, the technique is currently not sensitive enough to reliably detect coronary artery stenoses. Another approach is a single acquisition respiratory gated 3D technique which is less operator and patient dependent, requires less imaging time for an entire coronary protocol and is more comfortable for the patient than the 2D breath-hold approach. Initial experience demonstrates the capability to identify the major epicardial coronary vessels. But here too, further development is required to demonstrate coronary stenoses. A unique feature of MR imaging is the feasibility to non-invasively quantitate flow in the coronary arteries. This offers the potential to selectively determine the flow reserve of coronary arteries and to assess the functional and physiological implications of moderately severe stenoses. It can be envisaged that, although currently not apt to replace conventional coronary angiography, MR coronary angiography and flow measurement will become of use in the evaluation of specific, well defined clinical issues in coronary artery disease.

Current techniques of laryngotracheal reconstruction require a choice between prolonged stenting (conventional technique) or short-term stenting with maintenance of sedation and paralysis until the airway has stabilized (single-stage laryngotracheal reconstruction). An alternative method is proposed using microplates to provide immediate airway stabilization without stenting. This study was designed to evaluate the long-term effects of microplate repair of stenosis of the subglottis and trachea on the growing larynx. Subglottic stenosis was produced in piglets using a transoral endoscopic technique. Eight animals underwent repair of the stenosis using an anterior cricoid split with microplate distraction and stabilization of the cricoid cartilage and first tracheal ring. The distraction was maintained and airway growth continued for the duration of this study. However, with growth of the larynx the plates migrated away from their original position. In 50% of the animals followed up for 90 days the plates migrated into the airway lumen. This study suggests that rigid distraction of the stenotic airway with microplates is a viable alternative to more traditional methods of repair. However, plate removal at some interval after surgery is required in the growing larynx in order to prevent migration of the plate into the airway.

Use of the fiberoptic laser for treatment of tracheobronchial lesions in the adult is well established. However, there is a paucity of experience with the fiberoptic laser in the pediatric airway. Tracheal obstruction caused by granulation tissue or stenosis, as is often seen in children, may be effectively treated with this approach. This article documents the successful use as well as the technologic advantage of the flexible fiberoptic laser systems, primarily the potassium titanyl phosphate (KTP) laser, combined with standard pediatric rigid bronchoscopic equipment in 73 procedures involving 52 children (43 children younger than five years. with an average age of 21 months). Visualization was excellent, assisted or spontaneous ventilation was well maintained, and complications were few.

Purpose: Bacterial deoxyribonucleic acid (DNA) has been previously detected by polymerase chain reactions (PCR) in a significant percentage of culturally-sterile pediatric middle-ear effusions. The current study was designed to determine whether this represents the existence of viable bacteria or the persistence of residual DNA in the middle-ear cleft., Materials and Methods: The middle-ear cavities of two sets of chinchillas were inoculated with either: 1) 100 colony-forming units (CFU) of live Haemophilus influenzae, 2.2 x 10(6) CFU of pasteurized Moraxella catarrhalis, and 1000 ng of DNA (>10(8) genomic equivalents) from Streptococcus pneumoniae; or 2) 100 CFU of live S pneumoniae, 2.2 x 10(6) CFU of pasteurized M catarrhalis and 1000 ng of purified DNA from H influenzae. Animals were treated with ampicillin for 5 days beginning on day 3. A single-point longitudinal study design was used for sampling to eliminate the possibility of contamination., Results: No DNA was detectable from the heat-killed bacteria or the purified DNA after day 3. However, DNA from the live bacteria persisted through day 21, even though all specimens were culture-negative following the initiation of antimicrobial therapy., Conclusion: These findings indicate that purified DNA and DNA from intact but nonviable bacteria do not persist in the middle-ear cleft in the presence of an effusion, even following high copy inoculation. In contrast, antibiotic-treated bacteria persist in some viable state for weeks as evidenced by the differential ability of the PCR-based assay systems to detect the live bacteria, but not detect the heat-killed organisms.

Background: The clinical significance of anomalously originating coronary arteries depends on their proximal course. Diagnosis of this course by conventional x-ray coronary angiography alone may be equivocal. We postulated that with fast magnetic resonance (MR) angiography, accurate detection of anomalous coronary arteries and unambiguous delineation of their proximal course is feasible., Methods and Results: In a selected group of 38 patients, 19 of them having an anomalously originating coronary artery, a fast MR angiographic technique was used to study the proximal coronary anatomy. Blinded analysis of randomly ordered MR studies was performed independently by two observers. Both origin and proximal course of the coronary arteries were defined. Two cardiologists reviewed all x-ray coronary angiograms. After the separate analyses, a final consensus result was defined for each patient. In 37 patients, successful MR coronary angiography could be performed. Interobserver agreement for determining both origin and proximal course was 100%. An x-ray coronary angiogram was available in 36 patients. In 3 patients (all with an anomalous left main coronary artery originating from the right aortic sinus), there was disagreement about the proximal course between the results of MR and x-ray coronary angiography. Review of these cases demonstrated that MR angiography had unambiguously visualized the proximal coronary artery course, whereas the results of x-ray angiography had been equivocal. Thus, sensitivity and specificity for detecting anomalous coronary arteries and delineating their proximal course were 100%., Conclusions: These data suggest that fast MR angiography is highly accurate in determining the origin and delineating the proximal course of anomalous coronary arteries, even in those cases in which x-ray coronary angiographic diagnosis is difficult or even erroneous.