Conservation of the class I beta-tubulin gene in human populations and lack of mutations in lung cancers and paclitaxel-resistant ovarian cancers

The goal of this study was to determine the prevalence of sequence variants in the class I beta-tubulin (clone m40) gene and their occurrence in human tumors and cancer cell lines. DNA was isolated from 93 control individuals representing a wide variety of ethnicities, 49 paclitaxel-naive specimens (16 ovarian cancers, 17 non-small cell lung cancers, and 16 ovarian cancer cell lines), and 30 paclitaxel-resistant specimens (9 ovarian cancers, 9 ovarian cancer cell lines, and 12 ovarian cancer xenografts in nude mice). Denaturing high-performance liquid chromatography and direct sequence analysis detected two silent polymorphisms in exon 4, Leu217Leu (CTG/CTA) and Gly400Gly (GGC/GGT), with minor allele frequencies of 17 and 0.5%, respectively. Five nucleotide substitutions and one single-base deletion were detected in introns 1, 2, and 3 and in the 3' untranslated region. Analysis of 49 paclitaxel-naive and 30 paclitaxel-resistant specimens revealed no additional polymorphisms in the coding region. In addition, no amino acid replacements were found in chimpanzee, gorilla, and orangutan in comparison to human. Our data demonstrate a very high degree of sequence conservation in class I beta-tubulin, suggesting that all residues are important in tubulin structure and function. Individual variation in response to treatment with paclitaxel is not likely to be caused by genetic variations in the beta-tubulin drug target. Moreover, acquired mutations in class I beta-tubulin are unlikely to be a clinically relevant cause of drug resistance.     

A cohort evaluation of the pediatric ProSeal laryngeal mask airway in 100 children

Background: The ProSeal^® laryngeal mask airway (PLMA) has been available in pediatric sizes in the UK since 2007. Although several non‐UK studies have evaluated PLMAs in children, there are little published data regarding their use in this country. Having decided to introduce the pediatric PLMA into our practice, we chose to prospectively audit the first 100 uses as part of our clinical governance. Methods: We studied children undergoing elective surgery who were considered suitable for a supraglottic airway. We recorded patient, surgical and insertion details, device performance data and complications. Patient management was not altered by inclusion in this audit. Results: Twenty size 1.5, 55 size 2.0, 15 size 2.5 and 10 size 3.0 PLMAs were inserted in 100 consecutive children [median age 2 years (range 2 months to 10 years) and median weight 15 kg (range 4.9–60 kg)]. The overall first attempt success rate was 93% (size 1.5, 100%; size 2.0, 100%; size 2.5, 87%; size 3.0, 90%) and overall successful insertion rate was 99%. Median leak pressure was 25 cmH₂O. Outright failure was seen in one patient; complications were seen in another six patients (partial airway obstruction in five patients and mild laryngospasm in one patient), all of whom were transient and none of whom required intubation. No episodes of regurgitation were recorded. Conclusions: Even without prior experience and using nonconventional insertion, pediatric PLMAs (including size 1.5) can be easily inserted and provide an effective airway.     

Early decrease in nasal eosinophil proportion after nasal allergen challenge correlates with baseline bronchial reactivity to methacholine in children sensitized to house dust mites.

BACKGROUND: Allergic rhinitis is induced by an IgE mediated inflammation after allergen exposure of the membranes lining the nose which, in predisposed individuals, may constitute a risk factor for the occurrence of asthma. OBJECTIVE: To detect early changes in nasal inflammation after allergen exposure, 11 children [9.0 (7, 11) yrs], sensitized to house dust mites (HDM), with rhinoconjunctivitis and asthma and an age- and gender-matched control group (Ctr) were studied. METHODS: The following parameters were evaluated: i) pulmonary function; ii) bronchial reactivity to methacholine (MCh), expressed as Pd20MCh; iii) nasal brushing (NB) 'at baseline' and, on a separate day, 30 min after nasal allergen challenge (NAC). On NBs, the following markers of inflammation were evaluated: a) neutrophil and eosinophil proportion, b) 'intact to degranulated eosinophil' ratio, and c) expression of intercellular adhesion molecule (ICAM)-1 and HLA-DR by nasal epithelial cells. RESULTS: 'At baseline', allergic children showed elevated nasal eosinophilia and increased ICAM-1 and HLA-DR expression (p<0.05), as compared to Ctr. In allergic children, nasal eosinophilia correlated with Pd20MCh (p=0.002). The significant decrease in nasal eosinophilia observed after NAC (p=0.002) was associated with a significant decrease in the 'intact to degranulated eosinophil' ratio (p=0.001). Interestingly, correlations were still present between Pd20MCh and 'post NAC' eosinophilia (p=0.004) or the NAC-induced decrease in eosinophilia (p=0.010). CONCLUSIONS: In children sensitized to HDM, experimental allergen exposure is followed by an early depletion of nasal eosinophils. The correlation between allergen-induced changes in nasal eosinophilia and bronchial reactivity to MCh further supports the concept of a tight link between upper and lower respiratory tract involvement in respiratory allergy.     

Stable trichimerism after marrow grafting from 2 DLA-identical canine donors and nonmyeloablative conditioning

Although hematopoietic cell transplantation (HCT) is generally accomplished using a single donor, multiple donors have been used to enhance the speed of engraftment, particularly in the case of umbilical cord blood grafts. Here we posed the question in the canine HCT model whether stable dual-donor chimerism could be established using 2 DLA-identical donors. We identified 8 DLA-identical littermate triplets in which the marrow recipients received 2 Gy total body irradiation followed by marrow infusions from 2 donors and postgrafting immunosuppression. All 8 dogs showed initial "trichimerism," which was sustained in 5 dogs, while 2 dogs rejected one of the allografts and remained mixed chimeras, and 1 dog rejected both allografts. Immune function in one trichimeric dog, as tested by mixed leukocyte culture response and antibody response to sheep red blood cells, was found to be normal. Five dogs received kidney grafts from one of their respective marrow donors at least 6 months after HCT without immunosuppressive drugs, and grafts in 4 dogs are surviving without rejection. In summary, following nonmyeloablative conditioning, simultaneous administration of marrow grafts from 2 DLA-identical littermates could result in sustained trichimerism, and immunologic tolerance could include a kidney graft from one of the marrow donors.     

Correlations between exhaled nitric oxide levels,blood eosinophilia,and airway obstruction reversibility in childhood asthma are detectable only in atopic individuals

The aim of this study was to compare in atopic and nonatopic asthmatic children correlations between two inflammation parameters, i.e., blood eosinophilia and exhaled nitric oxide (FE(NO)), and pulmonary function values, at baseline and after beta(2)-adrenergic bronchodilators. Ninety-two steroid-naive asthmatic children were evaluated: 26 were skin prick test- and RAST-negative (nonatopic subjects), whereas 66 were atopic, 15 being sensitized only to house dust mites (monosensitized) and 51 to mites and to at least one other class of allergens (polysensitized). Baseline spirometric values (FEV(1) and FEF(25-75%)) were similar in atopic and nonatopic groups (P > 0.1, each comparison). However, when compared to nonatopic subjects, atopic children showed a significantly higher degree of blood eosinophilia (3.0% and 6.7% white blood cell count, respectively; P = 0.0001) and higher FE(NO) levels (6.8 ppb and 16.0 ppb, respectively; P = 0.0001). While a positive correlation between FE(NO) levels and blood eosinophilia was observed in atopic children (r = 0.25, P = 0.041), no correlations between these two inflammation parameters and baseline pulmonary function values were demonstrated in any of the asthmatic groups. Inhalation of a beta(2)-agonist drug induced in the two asthmatic populations similar improvements in FEV(1) and FEF(25-75%) and no changes in FE(NO) levels or blood eosinophilia. However, only in atopic children positive correlations were found between percent variation in FEV(1) (delta%FEV(1)) and FE(NO) levels (r = 0.35, P = 0.006) or blood eosinophilia (r = 0.26, P = 0.04). Within the atopic group, no differences were found between mono- and polysensitized individuals in all parameters evaluated. Thus only in atopic children did parameters of inflammation correlate with airway obstruction reversibility.     

Physiological properties of hERG 1a/1b heteromeric currents and a hERG 1b-specific mutation associated with Long-QT syndrome

Cardiac I Kr is a critical repolarizing current in the heart and a target for inherited and acquired long-QT syndrome (LQTS). Biochemical and functional studies have demonstrated that I Kr channels are heteromers composed of both hERG 1a and 1b subunits, yet our current understanding of I Kr functional properties derives primarily from studies of homooligomers of the original hERG 1a isolate. Here, we examine currents produced by hERG 1a and 1a/1b channels expressed in HEK-293 cells at near-physiological temperatures. We find that heteromeric hERG 1a/1b currents are much larger than hERG 1a currents and conduct 80% more charge during an action potential. This surprising difference corresponds to a 2-fold increase in the apparent rates of activation and recovery from inactivation, thus reducing rectification and facilitating current rebound during repolarization. Kinetic modeling shows these gating differences account quantitatively for the differences in current amplitude between the 2 channel types. Drug sensitivity was also different. Compared to homomeric 1a channels, heteromeric 1a/1b channels were inhibited by E-4031 with a slower time course and a corresponding 4-fold shift in the IC50. The importance of hERG 1b in vivo is supported by the identification of a 1b-specific A8V missense mutation in 1/269 unrelated genotype-negative LQTS patients that was absent in 400 control alleles. Mutant 1bA8V expressed alone or with hERG 1a in HEK-293 cells dramatically reduced 1b protein levels. Thus, mutations specifically disrupting hERG 1b function are expected to reduce cardiac I Kr and enhance drug sensitivity, and represent a potential mechanism underlying inherited or acquired LQTS.     

Inhibition of IL-32 activation by α-1 antitrypsin suppresses alloreactivity and increases survival in an allogeneic murine marrow transplantation model

Interleukin (IL)-32 was originally identified in natural killer cells and IL-2-activated human T lymphocytes. As T cells are activated in allogeneic transplantation, we determined the role of IL-32 in human mixed lymphocyte cultures (MLCs) and GVHD. In allogeneic MLCs, IL-32 increased two-fold in responding T cells, accompanied by five-fold increases of TNFα, IL-6, and IL-8. After allogeneic hematopoietic cell transplantation, IL-32 mRNA levels in blood leukocytes were statistically significantly higher in patients with acute GVHD (n = 10) than in serial samples from patients who did not develop acute GVHD (n = 5; P = .02). No significant changes in IL-32 levels were present in patients with treated (n = 14) or untreated (n = 8) chronic GVHD, compared with healthy controls (n = 8; P = .5, and P = .74, respectively). As IL-32 is activated by proteinase-3 (PR3), we determined the effect of the serine protease inhibitor α-1 antitrypsin (AAT) on IL-32 levels and showed suppression of IL-32 and T-lymphocyte proliferation in MLCs. In an MHC-minor antigen disparate murine transplant model, preconditioning and postconditioning treatment with AAT resulted in attenuation or prevention of GVHD and superior survival compared with albumin-treated controls (80% vs 44%; P = .04). These findings suggest that AAT modulates immune and inflammatory functions and may represent a novel approach to prevent or treat GVHD.     

Clonal cytogenetic abnormalities in patients with otherwise typical aplastic anemia

Between June 1981 and August 1986, 183 patients with the referring diagnosis of aplastic anemia were evaluated with cytogenetic studies and marrow biopsies. Seven patients (4%) on biopsy were found to have myelodysplasia. Seven of the 176 patients (4%) with marrow biopsies that confirmed the pathologic diagnosis of severe aplastic anemia were found to have clonal cytogenetic abnormalities in unstimulated marrow samples. Among the 169 patients with typical aplastic anemia and no cytogenetic abnormalities, 5 (3%) subsequently developed either myelodysplasia or leukemia. Two of three patients with pathologically confirmed aplastic anemia and clonal cytogenetic abnormalities, who were not transplanted, developed myelodysplasia. These results demonstrate that approximately 4% of patients with aplastic anemia have clonal cytogenetic abnormalities of marrow cells, and that while all patients with aplastic anemia may have some risk of developing leukemia, those with a cytogenetic abnormality have an especially high risk.     

IL-8 and airway neutrophilia in children with gastroesophageal reflux and asthma-like symptoms

Gastroesophageal reflux (GER) may induce respiratory symptoms (RS) through inhalation of acid gastric contents. To characterize the airway inflammation associated with this condition, 20 children [7.4 (0.9) yr old] with "difficult to treat" RS and a positive 24-h oesophageal pH monitoring (pHm) were studied and bronchoalveolar lavage (BAL) performed. The control group included 10 children [7.3 (1.3) yr], non-atopics, with a respiratory clinical history similar to the cases but no reflux, as demonstrated by a negative 24-h oesophageal pHm. On BAL samples, in addition to inflammatory indexes, the lipid-laden macrophage (LLM) index was determined as index of gastric content inhalation. As compared to controls, GER children had higher neutrophil proportion (P=0.002), higher LLM index (P=0.004) and higher concentrations of interleukin (IL)-8 (P=0.005), myeloperoxidase (MPO) (P=0.001) and elastase (P=0.045) in BAL fluid. In GER children, but not in controls, neutrophil proportion significantly correlated with LLM index (r=0.65, P=0.002), with IL-8 (r=0.62, P=0.003) and MPO levels (r=0.54, P=0.014) but not with elastase concentrations. These results suggest an active pathogenetic role of IL-8 in the recruitment and activation of neutrophils in the airways of children with GER, respiratory symptoms and BAL findings suggestive of gastric content aspiration.