Clinical and biochemical characteristics and bone mineral density of homozygous, compound heterozygous and heterozygous carriers of three novel IGFALS mutations.

OBJECTIVE: Acid-labile subunit (ALS) deficiency (ACLSD), caused by homozygous or compound heterozygous IGFALS mutations, is associated with moderate short stature, delayed puberty, low serum IGF-I and ALS and extremely low serum IGFBP-3. Its effect on birth weight, head circumference, bone mineral density (BMD), serum IGF-II and IGFBP-2 is uncertain, as well as the phenotype of heterozygous carriers of IGFALS mutations (partial ACLSD). DESIGN: From all available members of five Turkish families, carrying three mutations in exon 2 of IGFALS (c.1462G > A, p.Asp488Asn (families A, B, E); c.251A > G, p.Asn84Ser (families C and E) and c.1477del, p.Arg493fs (family D)), clinical, laboratory and BMD data were collected. METHODS: Auxological and biochemical findings were expressed as SDS for age and gender. Ternary complex formation in serum was investigated by size-exclusion chromatography. BMD using DXA bone densitometry was adjusted for height and age (Ha-BMD z-score). RESULTS: In ACLSD (n = 24), mean ± s.d. height SDS (-2.7 ± 1.2), head circumference SDS (-2.3 ± 0.5) and body mass index (BMI) (-0.6 ± 1.0 SDS) were lower than those in partial ACLSD (n = 26, P ≤ 0.01) and birth weight SDS (n = 7) tended to be lower (-2.2 ± 1.1 vs -0.6 ± 0.3 in partial ACLSD (P = 0.07)). Serum IGF-I was -3.7 ± 1.4 vs -1.0 ± 1.0, IGF-II: -5.6 ± 0.7 vs -1.3 ± 0.7, ALS: <-4.4 ± 1.2 vs -2.1 ± 0.9 and IGFBP-3: -9.0 ± 1.9 vs -1.6 ± 0.8 SDS respectively (P < 0.001). Ha-BMD z-score was similar and normal in both groups. CONCLUSIONS: To the known phenotype of ACLSD (i.e. short stature, reduced serum levels of IGF-I and ALS, extremely low serum IGFBP-3 and disturbed ternary complex formation), we add reduced birth weight, head circumference and serum IGF-II.

Phenotypic characterization of patients with deletions in the 3'-flanking SHOX region.

Context. Leri-Weill dyschondrosteosis is a clinically variable skeletal dysplasia, caused by SHOX deletion or mutations, or a deletion of enhancer sequences in the 3'-flanking region. Recently, a 47.5 kb recurrent PAR1 deletion downstream of SHOX was reported, but its frequency and clinical importance are still unknown. Objective. This study aims to compare the clinical features of different sizes of deletions in the 3'-flanking SHOX region in order to determine the relevance of the regulatory sequences in this region. Design. We collected DNA from 28 families with deletions in the 3'-PAR1 region. Clinical data were available from 23 index patients and 21 relatives. Results. In 9 families (20 individuals) a large deletion ( âˆ¼ 200-900 kb) was found and in 19 families (35 individuals) a small deletion was demonstrated, equal to the recently described 47.5 kb PAR1 deletion. Median height SDS, sitting height/height ratio SDS and the presence of Madelung deformity in patients with the 47.5 kb deletion were not significantly different from patients with larger deletions. The index patients had a median height SDS which was slightly lower than in their affected family members (p = 0.08). No significant differences were observed between male and female patients. Conclusions. The phenotype of patients with deletions in the 3'-PAR1 region is remarkably variable. Height, sitting height/height ratio and the presence of Madelung deformity were not significantly different between patients with the 47.5 kb recurrent PAR1 deletion and those with larger deletions, suggesting that this enhancer plays an important role in SHOX expression.

Improved diagnosis of the etiology of community-acquired pneumonia with real-time polymerase chain reaction.

BACKGROUND: Community-acquired pneumonia (CAP) remains an important cause of morbidity and mortality. Polymerase chain reaction (PCR) has been shown to be more sensitive than current standard microbiological methods and, therefore, may improve the accuracy of microbiological diagnosis for patients with CAP. METHODS: Conventional detection techniques and multiplex real-time PCR for atypical bacteria and respiratory viruses were performed on samples collected from 105 adults enrolled in a prospective study. An infiltrate was visible on each patient's chest radiograph, and a pneumonia severity index score was determined for each patient. RESULTS: Microbiological diagnoses were determined for 52 (49.5%) of 105 patients by conventional techniques and for 80 (76%) of 105 patients by real-time PCR. The time to obtain the result of real-time PCR could be reduced to 6 h. PCR methodology was significantly more sensitive for the detection of atypical pathogens and viruses (P< or =.001). Respiratory viral infections and mixed infections were detected in 15 (14.2%) and 3 (2.8%) of 105 patients, respectively, by conventional methods, but were detected in 59 (56.2%) and 28 (26.5%) of 105, respectively, by real-time PCR. Presence of a mixed infection was significantly associated with severe pneumonia (P=.002). Human rhinoviruses and coronaviruses, OC43 and 229E, were frequently identified pathogens. CONCLUSIONS: The combined real-time PCR assay is more sensitive for diagnosis of the main viruses and atypical bacteria that cause CAP compared with conventional methods, and obtains results in a clinically relevant time period.

Prospective study of respiratory viral infections in pediatric hemopoietic stem cell transplantation patients.

BACKGROUND: Community-acquired respiratory viruses are an important cause of respiratory disease in pediatric patients undergoing hemopoietic stem cell transplantation. However, there are no studies examining the impact of more rapid and sensitive diagnosis by real time polymerase chain reaction (PCR) in this population. We performed a prospective study to assess the impact of real time PCR diagnosis as well as protective isolation for community-acquired respiratory virus infections in pediatric patients undergoing hemopoietic stem cell transplantation. METHODS: During a 2-year period, 39 pediatric patients undergoing hemopoietic stem cell transplantation were analyzed for presence of respiratory viruses. Samples were taken at regular intervals and analyzed by culture and newly developed real time PCR methods. All patients were cared for in protective isolation. RESULTS: Respiratory symptoms were observed in 10 of the 39 cases (26%) and a virus was identified in 8 and 6 of these cases by PCR and culture, respectively. The PCR detected the respiratory infection a median of 8 days before culture. However, the morbidity of the respiratory infections was generally mild, and no mortality was observed. Additionally all infections were observed pretransplant or after discharge; no nosocomial infections were observed. CONCLUSIONS: The real time PCR assay is more rapid and sensitive than culture and could be used to screen patients before transplant or as respiratory symptoms present for timely diagnosis.

Rapid and sensitive method using multiplex real-time PCR for diagnosis of infections by influenza a and influenza B viruses, respiratory syncytial virus, and parainfluenza viruses 1, 2, 3, and 4.

Laboratory diagnosis of viral respiratory infections is generally performed by virus isolation in cell culture and immunofluorescent assays. Reverse transcriptase PCR is now recognized as a sensitive and specific alternative for detection of respiratory RNA viruses. A rapid real-time multiplex PCR assay was developed for the detection of influenza A and influenza B viruses, human respiratory syncytial virus (RSV), parainfluenza virus 1 (PIV1), PIV2, PIV3, and PIV4 in a two-tube multiplex reaction which used molecular beacons to discriminate the pathogens. A total of 358 respiratory samples taken over a 1-year period were analyzed by the multiplex assay. The incidence of respiratory viruses detected in these samples was 67 of 358 (19%) and 87 of 358 (24%) by culture and real-time PCR, respectively. Culture detected 3 influenza A virus, 2 influenza B virus, 57 RSV, 2 PIV1, and 2 PIV3 infections. All of these culture-positive samples and an additional 5 influenza A virus, 6 RSV, 2 PIV1, 1 PIV2, 1 PIV3, and 3 PIV4 infections were detected by the multiplex real-time PCR. The application of real-time PCR to clinical samples increases the sensitivity for respiratory viral diagnosis. In addition, results can be obtained within 6 h, which increases clinical relevance. Therefore, use of this real-time PCR assay would improve patient management and infection control.

Development and clinical evaluation of an internally controlled, single-tube multiplex real-time PCR assay for detection of Legionella pneumophila and other Legionella species.

A multiplex real-time PCR assay for detection of Legionella pneumophila and Legionella spp. and including an internal control was designed. Legionella species, L. pneumophila, and the internal control were detected simultaneously by probes labeled with 6-carboxy-fluorescein, hexachlorofluorescein, and indodicarbocyanine, respectively. Therefore, no postamplification analysis was required in order to distinguish the targets. The sensitivity of both assays was 2.5 CFU/ml, and from analysis of 10 culture-positive and 74 culture-negative samples from patients investigated for legionellosis, 100% agreement was observed by both assays in comparison to culture. Four additional positives were found by the multiplex real-time PCR assay in the Legionella culture-negative samples.

Evaluation of real-time PCR for detection of and discrimination between Bordetella pertussis, Bordetella parapertussis, and Bordetella holmesii for clinical diagnosis.

PCR is increasingly being used as a diagnostic test for the detection of Bordetella pertussis and Bordetella parapertussis DNA, as it has improved sensitivity and specificity in comparison to conventional techniques. The assay described here uses the two insertion sequences IS481 and IS1001 for B. pertussis and B. parapertussis, respectively, with detection by molecular beacons. The real-time PCR for IS481 detects both B. pertussis and Bordetella holmesii, and the real-time PCR for IS1001 detects both B. parapertussis and B. holmesii. By performing both assays discrimination between B. pertussis and B. parapertussis can be obtained. The sensitivity was 1 to 10 CFU/ml for B. pertussis, 10 CFU/ml for B. parapertussis, and 10 CFU/ml for B. holmesii in both assays. The clinical sensitivity of the B. pertussis assay was not affected by duplexing with an internal control PCR. Real-time PCR, conventional PCR, and culture were performed on 57 clinical samples. Eight of the 57 (14%) were found positive by culture, 19 of 57 (33%) were found positive by conventional PCR, and 22 of 57 (39%) were found positive by real-time PCR. One sample was inhibitory. When the B. pertussis assay was compared with a clinical standard for B. pertussis infection, sensitivity was 38, 83, and 100% and specificity was 100, 97, and 97% for culture, conventional PCR, and real-time PCR, respectively. The real-time PCR designed for B. pertussis and B. parapertussis provides sensitive and specific diagnosis of B. pertussis and B. parapertussis infections and is therefore suitable for implementation in the diagnostic laboratory.

Comparison and evaluation of real-time PCR, real-time nucleic acid sequence-based amplification, conventional PCR, and serology for diagnosis of Mycoplasma pneumoniae.

Mycoplasma pneumoniae is a common cause of community-acquired pneumonia and lower-respiratory-tract infections. Diagnosis has traditionally been obtained by serological diagnosis, but increasingly, molecular techniques have been applied. However, the number of studies actually comparing these assays is limited. The development of a novel duplex real-time PCR assay for detection of M. pneumoniae in the presence of an internal control real-time PCR is described. In addition, real-time nucleic acid sequence-based amplification (NASBA) on an iCycler apparatus is evaluated. These assays were compared to serology and a conventional PCR assay for 106 clinical samples from patients with lower-respiratory-tract infection. Of the 106 samples, 12 (11.3%) were positive by all the molecular methods whereas serology with acute sample and convalescent samples detected 6 (5.6%) and 9 (8.5%), respectively. Clinical symptoms of the patients with Mycoplasma-positive results were compared to those of the other patients with lower-respiratory-tract infections, and it was found that the results for mean lower age numbers as well as the presence of chills, increased erythrocyte sedimentation rate, and raised C-reactive protein levels showed significant differences. Molecular methods are superior for diagnosis of M. pneumoniae, providing more timely diagnosis. In addition, using real-time methods involves less hands-on time and affords the ability to monitor the reaction in the same tube.

PCR-based DNA fingerprinting of Staphylococcus haemolyticus to investigate nosocomial infections.

OBJECTIVE: To apply PCR-based DNA fingerprinting in a clinical microbiology laboratory to investigate nosocomial infections with Staphylococcus haemolyticus. METHODS: DNA fingerprints were generated by PCR on 99 S. haemolyticus isolates using different primer combinations based on ERIC, REP or arbitrarily chosen simple repeat sequences. RESULTS: Primer combinations REP1+(GTC)6 and ERIC1+ERIC2 had sufficient discrimatory power and were chosen to analyze the clinical isolates. DNA fingerprint patterns from strains isolated from the patients nursed in the same hospital ward in the period 1991--94 were approximately 90% similar to each other. One staff member, sampled in 1991, carried a strain with a similar fingerprint. CONCLUSIONS: PCR based DNA fingerprinting is a suitable method to perform in a clinical laboratory. An S. haemolyticus strain appeared to be endemic in the hospital ward and had most probably been transmitted from patient to patient. S. haemolyticus may carry glycopeptide resistance and needs attention as a causative agent of nosocomial infections.