The prevalence of gastroesophageal reflux in children with tracheomalacia and laryngomalacia

OBJECTIVE: We conducted a retrospective study to determine the relationship between gastroesophageal reflux (GER) and large airways malacia in infancy. METHODS: One hundred sixteen children referred for chronic respiratory problems who were between the ages of 3 and 28 months were investigated. All of them underwent flexible bronchoscopy and chest radiography. Eighteen children had laryngomalacia, 13 had tracheomalacia, and 23 had combined laryngotracheomalacia. During bronchoscopy, BAL was performed. An analysis of macrophages in the BAL fluid for lipid content was performed. Fifty-four children with laryngomalacia and tracheomalacia constituted the study group, and 62 children were in the control group. Reflux studies were obtained for 40 children from the study group and 41 from the control group. RESULTS: In the study group, 28 children (70%) had GER documented by reflux studies compared with 16 children (39%) in the control group (p < 0.01). In the control group, GER was found mainly among those with recurrent bilateral pneumonia. The lipid-laden macrophage score was correlated with the documented GER. CONCLUSION: GER is prevalent among infants with large airways malacia, and treatment of this group with antireflux therapy should be considered.     

Human leukocyte antigen (HLA) class II association with rheumatic heart disease in Pakistan

BACKGROUND AND AIM of the study: Rheumatic heart disease (RHD) is widespread in Pakistan. Specific alleles of the human leukocyte antigen (HLA) system are associated with RHD in various world populations. The study aim was to investigate the involvement of HLA class II alleles in genetic susceptibility to RHD in patients with relatively homogeneous clinical manifestations, in Pakistan. METHODS: Blood samples were collected from 114 unrelated patients (94 females, 20 males) with rheumatic mitral valve disease, predominantly mitral stenosis, as assessed by echocardiography. The control group comprised 109 unrelated, ethnically matched, healthy individuals (60 females, 49 males) with normal echocardiograms. Genomic DNA was extracted from venous blood using a standard phenol/chloroform extraction procedure. HLA-DRB, -DQA1, and -DQB1 alleles were typed using polymerase chain reaction with sequence-specific primers. HLA allele and haplotypes frequencies were then calculated. RESULTS: A significantly higher frequency of DRB1*07 was observed in patients as compared to controls (one-way parametric analysis of variance, F = 4.84, p = 0.028; OR = 1.76, p = 0.039). No alleles for the HLA-DQA1 or -DQB1 loci were associated with the disease. HLA-DRB1*07-DQA1*0501-DQB1*02, the only haplotype that differed significantly between patients and controls (one-way parametric Anova, F = 4.866, p = 0.028; OR = 7.33, p = 0.06), did not exhibit significant linkage disequilibrium. CONCLUSION: These results show that HLA-DRB1*07, associated with RHD in various world populations, is also associated with RHD in the Pakistani population. The validation of HLA associations with RHD, which is observed in different world populations, may lead to the development of a cost-effective strategy in the primary prevention of this disease.     

Organization and stability of a polytopic membrane protein: deletion analysis of the lactose permease of Escherichia coli.

The overall topology of polytopic membrane proteins is thought to result from either the oriented insertion of the N-terminal alpha-helical domain followed by passive insertion of subsequent helices or from the function of independent topogenic determinants dispersed throughout the molecules. By using the lactose permease of Escherichia coli, a well-characterized membrane protein with 12 transmembrane domains and the N and C termini on the cytoplasmic surface of the membrane, we have studied the insertion and stability of in-frame deletion mutants. So long as the first N-terminal and the last four C-terminal putative alpha-helical domains are retained, stable polypeptides are inserted into the membrane, even when an odd number of helical domains is deleted. Moreover, even when an odd number of helices is deleted, the C terminus remains on the cytoplasmic surface of the membrane, as judged by lacY-phoA fusion analysis. In addition, permease molecules devoid of even or odd numbers of putative transmembrane helices retain a specific pathway for downhill lactose translocation. The findings imply that relatively short C-terminal domains of the permease contain topological information sufficient for insertion in the native orientation regardless of the orientation of the N terminus.     

Activating point mutations in cyclin-dependent kinase 4 are not seen in sporadic pituitary adenomas,insulinomas or Leydig cell tumours

Cell cycle dysregulation is one of the defining features of cancer. Cyclin-dependent kinase 4 (CDK4), together with its regulatory subunit cyclin D, governs cell cycle progression through the G1 phase. Cyclin-dependent kinase inhibitors, including p16(INK4A) (encoded by CDKN2A), in turn regulate CDK4. In particular, dysregulation of the p16/CDK4/cyclin D complex has been established in a variety of types of human tumours. Dominant activating mutations affecting codon 24 of the CDK4 gene (replacement of Arg24 by Cys or His) render CDK4 insensitive to p16(INK4) inhibition and are responsible for melanoma susceptibility in some kindreds. However, 'knock-in' mice homozygous for the CDK4(R24C) mutation were noted to develop multiple neoplasia, most commonly including endocrine tumours: pituitary adenomas, insulinomas and Leydig cell testicular tumours. We therefore speculated that sporadic human endocrine tumours might also harbour such mutations. The aim of the current study was to analyze the CDK4 gene for the two characterized activating mutations, R24C and R24H, in sporadic human pituitary adenomas, insulinomas and Leydig cell tumours. We used DNA extracted from 61 pituitary adenomas, and paired tumorous and neighboring normal genomic DNA extracted from 14 insulinoma and 6 Leydig cell tumour samples. Genomic DNA from patients with familial melanoma harbouring the R24C or the R24H mutations served as positive controls. All samples were subjected to PCR, mutation-specific restriction digests and/or sequencing. Both methodologies failed to detect mutations at these two sites in any of the sporadic endocrine tumours including pituitary adenomas, benign or malignant insulinomas or Leydig cell tumours, while the positive controls showed the expected heterozygote patterns. Protein expression of CDK4 was demonstrated by immunohistochemistry and Western blotting in pituitary and pancreatic samples. These data suggest that the changes in the regulatory 'hot-spot' on the CDK4 gene, causing various endocrine tumours in CDK4(R24C/R24C )mice, are not a major factor in sporadic pituitary, insulin beta-cell or Leydig cell tumorigenesis.     

Short-term course and outcome of treatments of pleural empyema in pediatric patients: repeated ultrasound-guided needle thoracocentesis vs chest tube drainage

BACKGROUND: Several reports have suggested that early chest tube drainage (CTD) may not be necessary in the treatment of severe pleural empyema (PE) in pediatric patients if appropriate antibiotic therapy and supportive care are provided. OBJECTIVES: A prospective open study to compare the short-term course of two treatment protocols of severe PE in pediatric patients. STUDY DESIGN: One group of 32 patients was treated with early insertion of a chest tube for CTD, and a second group of 35 patients was treated by a repeated ultrasound-guided needle thoracocentesis (RUSGT). The severity of the empyema was assessed by chest radiograph, the amount of fluid drained, the number of days the patient had experienced a fever, and the duration of antibiotic treatment. RESULTS: No significant differences were found between the two groups (RUSGT vs CTD) in all of the following measurements: mean (plus minus SD) duration of a temperature > or = 39 degreesC, 6.2 +/- 2.4 vs 6.5 +/- 1.8 days, respectively; mean duration of a temperature > or = 38 degreesC, 9 +/- 3.9 vs 8.2 +/- 4.5 days, respectively; fluid drained, 35.1 + 23.8 vs 30 +/- 28.2 mL/kg, respectively; duration of antibiotic treatment, 30 +/- 13.2 vs 30.2 +/- 7.3 days, respectively; and length of hospitalization and home IV treatment, 22 +/- 7.6 vs 24.2 +/- 7.5 days, respectively. A failure to respond to treatment occurred in three patients in the RUSGT-treated group and in five patients in the CTD-treated group. The failure to respond occurred in the RUSGT-treated group only in those patients with very large empyemas that caused mediastinal deviation. CONCLUSION: The treatment of PE by RUSGT is as efficacious as CTD, unless PE causes mediastinal deviation.     

The Escherichia coli multidrug transporter MdfA catalyzes both electrogenic and electroneutral transport reactions

The resistance of cells to many drugs simultaneously (multidrug resistance) often involves the expression of membrane transporters (Mdrs); each recognizes and expels a broad spectrum of chemically unrelated drugs from the cell. The Escherichia coli Mdr transporter MdfA is able to transport differentially charged substrates in exchange for protons. This includes neutral compounds, namely chloramphenicol and thiamphenicol, and lipophilic cations such as tetraphenylphosphonium and ethidium. Here we show that the chloramphenicol and thiamphenicol transport reactions are electrogenic, whereas the transport of several monovalent cationic substrates is electroneutral. Therefore, unlike with positively charged substrates, the transmembrane electrical potential (negative inside) constitutes a major part of the driving force for the transport of electroneutral substrates by MdfA. These results demonstrate an unprecedented ability of a single secondary transporter to catalyze discrete transport reactions that differ in their electrogenicity and are governed by different components of the proton motive force.     

Molecularly imprinted polymeric coatings for sensitive and selective gravimetric detection of artemether

Monitoring antimalarial drugs is necessary for clinical assays, human health, and routine quality control practices in pharmaceutical industries. Herein, we present the development of sensor coatings based on molecularly imprinted polymers (MIPs) combined with quartz crystal microbalance (QCM) for sensitive and selective gravimetric detection of an antimalarial drug: artemether. The MIP coatings are synthesized by using artemether as the template in a poly(methacrylic acid-co-ethylene glycol dimethacrylate) matrix. Artemether-MIP and the non-imprinted polymer (NIP) control or reference layers are deposited on 10 MHz dual-electrode QCM by spin coating (187 ± 9 nm layer thickness after optimization). The coatings are characterized by FTIR spectroscopy and atomic force microscopy that reveal marked differences among the MIP and NIP. The MIP-QCM sensor exhibits high sensitivity (0.51 Hz ppm⁻¹) with sub-10 ppm detection and quantification limits. The MIP-QCM sensor also exhibits a 6-fold higher sensitivity compared to the NIP-QCM, and a dynamic working range of 30–100 ppm. The response time of MIP-QCM devices for a single cycle of analyte adsorption, signal saturation, and MIP regeneration is less than 2.5 min. The sensor also demonstrates selectivity factors of artemether-MIP of 2.2 and 4.1 compared to artemisinin and lumefantrine, respectively. Reversibility tests reveal less than 5% variation in sensor responses over three cycles of measurements at each tested concentration. The MIP-QCM showed lower detection limits than conventional HPLC-UV, and faster response time compared to HPLC-UV and liquid chromatography-mass spectrometry (LC-MS).

Chemical structures of the antimalarial drugs: artemisinin, artemether (a methyl ether derivative of artemisinin), and lumefantrine.     

Investigation of antioxidant and anti-nociceptive potential of isoxazolone,pyrazolone derivatives,and their molecular docking studies

A series of new isoxazolone ( 3a – d ) and pyrazolone ( 4a – d ) derivatives were synthesized and assessed for their antioxidant and analgesic activity. Among synthesized compounds, 3b and 4b having nitro (NO₂) group show high analgesic activity at a dose of 6 mg/kg. Analgesic activity was further proceeded to explore the contribution of opioidergic mechanisms in the mediation of analgesic effects. Animals were administered with naloxone, a nonselective opioid inverse agonist, at the dose of 0.5 mg/kg. The results obtained suggested that the analgesic effects of the synthesized compounds were not reversed by naloxone, specifying that the compounds 3b and 4b do not follow the opioidergic pathway in order to relieve pain in animal models. Further, the binding interactions of compounds 3b and 4b were analyzed by docking them against nonopioid receptors COX-1 (3N8X) and COX-2 (3LN1). The results demonstrate the analgesic potential of isoxazolone and pyrazolone derivatives, especially compounds 3b and 4b can be considered promising lead molecules for further investigation and development into potent analgesic drugs. In addition, the antioxidant potential of compounds was also found to be related to better analgesic activity, thus providing an insight into the role of oxidative stress in the mediation of analgesia.     

Epidemiologic profile of pediatric brain tumors in Morocco

Introduction  

Brain tumors are the most common solid tumors diagnosed among children below 15 years worldwide. However, little is known about the profile of pediatric brain tumors in Africa. The purpose of this study was to further elaborate the epidemiological profile of pediatric brain tumors in Africa, specifically Morocco.