Quantitative lymph node burden as a 'very-high-risk' factor identifying head and neck cancer patients benefiting from postoperative chemoradiation.

Background: Adjuvant chemoradiation (CRT) is standard for head and neck squamous cell carcinoma (HNSCC) patients with positive margins or extranodal extension (ENE) following surgery. However, emerging evidence suggests the number of positive lymph nodes (LNs) is the dominant determinant of survival in non-oropharyngeal HNSCC and thus may better identify those benefiting from treatment intensification. Patients and methods: Patients from the National Cancer Database diagnosed with non-oropharyngeal HNSCC (oral cavity, larynx, hypopharynx) between 2004 and 2014 and undergoing surgical resection, neck dissection, and postoperative radiotherapy (RT) were included. Multivariable regression with first-order interaction terms was used to model the interaction between postoperative CRT and continuous number of positive LNs with respect to overall survival. Results: In total, 7144 patients met inclusion criteria. In multivariable analysis, increasing number of positive LNs was associated with both increasing mortality (P < 0.001) and increasing benefit from postoperative CRT versus RT alone (interaction P < 0.001). While there was no benefit from postoperative CRT in patients with 0-2 LN+ [hazard ratio (HR) 0.96, 95% confidence interval (CI) 0.86-1.07, P = 0.47], increased benefit was seen in those with 3-5 LN+ (HR 0.84, 95% CI 0.70-1.00, P = 0.05) and those with ≥6 LN+ (HR 0.65, 95% CI 0.51-0.82, P < 0.001) in multivariable models. By contrast, margin status and ENE did not reliably identify patients benefitting from postoperative CRT based on statistical tests of interaction. Even in patients with ENE, positive margins, or both, only those with ≥6 LN+ had improved survival with postoperative CRT. Conclusion: Increasing metastatic nodal burden was associated with increased benefit from CRT compared with RT alone, surpassing conventional high-risk factors in identifying patients benefiting from CRT. Stratification by metastatic LN number may characterize a very-high-risk patient cohort best suited for treatment intensification.

The role of host microfilaments and microtubules during opsonin-independent interactions of Cryptococcus neoformans with mammalian lung cells.

The purpose of this investigation was to characterise the interactions of Cryptococcus neoformans with mammalian host alveolar epithelial cells and alveolar macrophages, with emphasis on the roles of the cryptococcal capsule and the host cell cytoskeletons. The adherence and internalisation of C. neoformans into mammalian lung cells and the roles of host cell cytoskeletons in host-pathogen interactions were studied using in vitro models coupled with a differential fluorescence assay, fluorescence staining, immunofluorescence and drug inhibition of actin and microtubule polymerisation. Under conditions devoid of opsonin and macrophage activation, C. neoformans has a high affinity towards MH-S alveolar macrophages, yet associated poorly to A549 alveolar epithelial cells. Acapsular C. neoformans adhered to and internalised into the mammalian cells more effectively compared to encapsulated cryptococci. Acapsular C. neoformans induced prominent actin reorganisation at the host-pathogen interface in MH-S alveolar macrophages, but minimally affected actin reorganisation in A549 alveolar epithelial cells. Acapsular C. neoformans also induced localisation of microtubules to internalised cryptococci in MH-S cells. Drug inhibition of actin and microtubule polymerisation both reduced the association of acapsular C. neoformans to alveolar macrophages. The current study visualises and confirms the interactions of C. neoformans with mammalian alveolar cells during the establishment of infection in the lungs. The acapsular form of C. neoformans effectively adhered to and internalised into alveolar macrophages by inducing localised actin reorganisation, relying on the host's actin and microtubule activities.

Neural stem cells harvested from live brains by antibody-conjugated magnetic nanoparticles.

It stems from the magnetism: The extraction of stem/progenitor cells from the brain of live animals is possible using antibodies conjugated to magnetic nanoparticles (Ab-MNPs). The Ab-MNPs are introduced to a rat's brain with a superfine micro-syringe. The stem cells attach to the Ab-MNPs and are magnetically isolated and removed. They can develop into neurospheres and differentiate into different types of cells outside the subject body. The rat remains alive and healthy.

The pili of Aeromonas hydrophila: identification of an environmentally regulated "mini pilin".

Ultrastructural studies of Aeromonas hydrophila strain AH26 revealed two distinctive pilus types: "straight" pili appear as brittle, rod-like filaments, whereas "flexible" pili are supple and curvilinear. Straight pili are produced constitutively under all tested conditions of growth. In contrast, the expression of flexible pili is regulated by physical and chemical variables, being produced at 22 vs. 37 degrees C, in a liquid vs. a solid medium, and when the availability of free-iron is reduced by the presence of deferoxamine mesylate. Both pilus proteins were purified and biochemically and functionally characterized. The major repeating subunit of the straight pilus is a 17,000-mol wt polypeptide with amino acid sequence homology with Escherichia coli type 1 and Pap pili. The flexible pilus filament is a homopolymer composed of a novel 46 amino acid polypeptide. Resistance of the flexible pilus filament to disaggregation using various chemical treatments was demonstrated; its stability as a polymer and its apparent mechanical strength seem to be conferred by a 20 amino acid hydrophobic, COOH-terminal domain. Purified straight pili lack hemagglutinating function. In contrast, purified flexible pili cause the agglutinin of human, guinea pig, ovine, bovine, and avian erythrocytes, although this property could only be demonstrated in the presence of divalent cations and was most evident at 4 vs. 22 degrees C. Taken together, these results suggest that the pathogenic and ecological roles of the flexible pilus are related to this species' existence as a free-living organism in aquatic environments and its ability to cause infections, both in cold-blooded vertebrates and the human intestine.

An inducible bundle-forming pilus of enteropathogenic Escherichia coli.

Enteropathogenic Escherichia coli (EPEC), a cause of childhood diarrhea, grow on the surface of the small intestine and on cultured epithelial cells as colonies of adherent bacteria. When propagated on solid medium containing blood or attached to HEp-2 cells, EPEC express ropelike bundles of filaments, termed bundle-forming pili (BFP), that create a network of fibers that bind together the individual organisms. BFP were found to be expressed by five EPEC serogroups, each harboring a approximately 92-kilobase plasmid previously known to be important for virulence in humans. When two of these strains were cured of this plasmid, they neither expressed BFP nor grew as adherent colonies. An antiserum to BFP reduced the capacity of EPEC to infect cultured epithelial cells. BFP are composed of a repeating subunit of 19,500 daltons, the amino-terminal amino acid sequence of this subunit is homologous to that of the toxin-coregulated pilin of Vibrio cholerae.

Selective use of radioactive iodine (RAI) in thyroid cancer: No longer "one size fits all".

A remarkable, evidence-based trend toward de-escalation has reformed the practice of radioactive iodine (RAI) administration for thyroid cancer patients. Updated guidelines have supported both decreased RAI doses for select populations, as well as expanded definitions of low-risk and intermediate-risk patients that may not require RAI. Correspondingly, there is now increased flexibility for hemithyroidectomy without need for RAI, and relaxed TSH suppression targets for low-risk thyroidectomy patients. Clinical judgment remains indispensable where multiple risk factors co-exist that individually are not indications for RAI. This is especially salient in intermediate-risk patients with a less than excellent response to therapy, determined through thyroglobulin and ultrasound surveillance. Such judgment, however, may lead to patterns of inappropriate RAI practices or overuse with little benefit to the patient and unnecessary harm. A multidisciplinary, risk-adapted approach is ever more important and obliges the surgeon to understand the likelihood that their patients will receive RAI. The risks and benefits of RAI, its evolved role in contemporary guidelines, and current patterns of use among endocrinologists are reviewed, as well as the practical implications for thyroid surgeons.

Determinants of chronic obstructive pulmonary disease in Chinese patients in Hong Kong.

BACKGROUND: The prevalence of chronic obstructive pulmonary disease (COPD) is rising in many parts of the world. This is a study of risk factors for COPD in Chinese patients in Hong Kong. DESIGN: Case-control study matched by sex and age (+/-5 years). METHODS: A total of 289 consecutive patients with COPD were recruited from out-patient clinics while healthy controls were recruited from two sources: random population and community centres for senior citizens. All patients and controls underwent a questionnaire-based interview and spirometry. RESULTS: The mean ages of COPD patients and controls were 71.1 +/- 9.4 and 67.5 +/- 9.3 years, respectively. The male to female ratio of COPD patients was 5 to 1. Smoking was found to be the most important determinant for COPD, followed by poor education and low body mass index adjusted for confounders. A dose-dependent relationship was found between the risk of COPD and pack-years smoked. Place of birth, exposure to environmental tobacco smoke and a history of asthma and tuberculosis were not associated with increased risk of COPD. CONCLUSION: Despite a progressive reduction in prevalence, smoking remains the most important predictor of COPD in Hong Kong. Greater anti-smoking efforts are warranted.

Functional regions of the mouse interleukin-10 receptor cytoplasmic domain.

The functions of wild-type and mutant mouse interleukin-10 receptors (mIL-10R) expressed in murine Ba/F3 cells were studied. As observed previously, IL-10 stimulates proliferation of IL-10R-expressing Ba/F3 cells. Accumulation of viable cells in the proliferation assay is to a significant extent balanced by concomitant cell death. Moreover, growth in IL-10 also induces a previously unrecognized response, differentiation of the cells, as evidenced both by formation of large clusters of cells in cultures with IL-10 and by induction or enhancement of expression of several cell surface antigens, including CD32/16, CD2, LECAM-1 (v-selectin), and heat-stable antigen. Two distinct functional regions near the C terminus of the mIL-10R cytoplasmic domain which mediate proliferation were identified; one of these regions also mediates the differentiation response. A third region proximal to the transmembrane domain was identified; removal of this region renders the cell 10- to 100-fold more sensitive to IL-10 in the proliferation assay. In cells expressing both wild-type and mutant IL-10R, stimulation with IL-10 leads to tyrosine phosphorylation of the kinases JAK1 and TYK2 but not JAK2 or JAK3 under the conditions tested.

p53 Status does not affect photodynamic cell killing induced by hypericin.

PURPOSE: Given that p53 is a tumor suppressor that plays a central role in the cellular response to DNA damage and that more than 50% of all cancers have mutated p53, the wider utility of photodynamic therapy (PDT) in the treatment of cancer will depend on an understanding of whether p53 status modulates response to PDT. In this study, we investigated the photosensitivity of isogenic cell lines that differ only in their p53 status to PDT using hypericin as the photosensitizer. METHODS: Acute (MTT) and chronic (clonogenic) cytotoxic assays were performed on two osteosarcoma cell-lines (U2OS and U2OS+p53DD) that are isogenic except that the latter expresses dominant negative p53. The inducible expression of p53 was determined on western blots. Uptake of hypericin, cell cycle profile analysis, measurement of membrane phosphatidylserine externalization and changes in mitochondrial membrane potential were investigated using flow cytometry. RESULTS: Hypericin uptake was observed to be equivalent in U2OS and U2OS+p53DD cells. There were no significant differences in cell killing between these cell-lines in both the MTT and clonogenic assays (IC(50) of 0.4 microg/ml from MTT assay). p53 expression did not increase up to 24 h after PDT treatment in both cell lines. There were also no significant differences in the cell-cycle arrest profiles and timing of onset of apoptosis. CONCLUSIONS: Taken together, these results suggest that the status of p53 may not be important in PDT-mediated cell killing or induction of apoptosis. By extension, these results imply that PDT may be used with equal efficacy for the treatment of p53-positive and -negative tumors.

Genetic control of cadmium tolerance in Drosophila melanogaster.

Files from a transgenic line of Drosophila melanogaster with two copies of the metallothionein allele Mtn3 were more tolerant to cadmium than strains with only one copy of the gene. However, flies with the Mtn3 allele were as tolerant as flies with the Mtn3 allele, despite the level of expression of Mtn3 being three times higher than of Mtn3. We propose that the substitution of Lys-40 (in Mtn3) for Glu-40 (in Mtn1) accounts for a reduction in binding affinity of Mtn1, which offsets the increased expression levels.

Prevalence of snoring and sleep-disordered breathing in a student population.

INTRODUCTION: The prevalence of snoring and sleep-disordered breathing (SDB) in young adults in Southeast Asian countries is unknown. We aim to determine the symptoms and prevalence of SDB in a university student population using a questionnaire survey followed by home sleep monitoring. METHODS: The Sleep and Health Questionnaire (a modified version of the Specialized Centers of Research Sleep Questionnaire, translated into Chinese) was distributed to all first-year students (1,306 male and 1,757 female) enrolled in the Chinese University of Hong Kong. Subsequently, those students who returned the questionnaires were randomly chosen to undergo portable home sleep monitoring using the MESAM IV device (Madaus Medizin-Elektronik; Freiburg, Germany). RESULTS: A total of 1,910 replies were obtained from 3,063 questionnaires sent by mail (response rate, 62.4%). The female to male ratio was 1.8:1, with mean age of 19.4 years (SD, 1.3 years) and mean body mass index (BMI) of 20.0 (SD, 2.5). Overall, 25.7% of subjects reported snoring; 10.7% and 42.1% reported impaired performance ability and daytime sleepiness, respectively. Of the 88 subjects who underwent overnight sleep monitoring, 66 subjects (75%) were snorers and 8 subjects (9%) snored > 10% of the night. Male subjects had a higher BMI (p < 0.001) and tended to snore more often than female subjects (p = 0.06). Subjects with an oxygen desaturation index (ODI) > or = 3 had a BMI > 22 (p < 0.05). On sleep study, nine subjects (10.2%) and two subjects (2.3%) had a respiratory disturbance index (RDI) > or = 3 and an RDI > or = 5, respectively, associated with self-reported sleepiness, giving a minimum estimated prevalence of SDB as 0.1% (RDI > or = 5) in the study population. There was no correlation between recorded snoring with either RDI or self-reported sleepiness. Questionnaire responses, neck circumference, and alcohol consumption did not predict the occurrence of SDB. CONCLUSION: Snoring was prevalent, while SDB was uncommon in this student population. However, snoring and self-reported symptoms by questionnaire were poor predictors for SDB. Male gender showed a trend as an independent predictor for snoring, but not for SDB.

Successful treatment of disseminated coccidioidomycosis with amphotericin B lipid complex.

Coccidioidomycosis is endemic in regions of the Americas, but this infection may be encountered in travellers who return from an endemic region. A case is reported of a disseminated infection in a Hong Kong Chinese man, who was successfully treated with amphotericin B lipid complex (ABLC) after intolerance and toxicity precluded the use of other antifungal agents. Lipid-based formulations of amphotericin B merit further evaluation in the treatment of coccidioidomycosis and other systemic mycoses.

Dysregulation of Wnt inhibitory factor 1 (Wif1) expression resulted in aberrant Wnt-ß-catenin signaling and cell death of the cloaca endoderm, and anorectal malformations.

In mammalian urorectal development, the urorectal septum (urs) descends from the ventral body wall to the cloaca membrane (cm) to partition the cloaca into urogenital sinus and rectum. Defective urs growth results in human congenital anorectal malformations (ARMs), and their pathogenic mechanisms are unclear. Recent studies only focused on the importance of urs mesenchyme proliferation, which is induced by endoderm-derived Sonic Hedgehog (Shh). Here, we showed that the programmed cell death of the apical urs and proximal cm endoderm is particularly crucial for the growth of urs during septation. The apoptotic endoderm was closely associated with the tempo-spatial expression of Wnt inhibitory factor 1 (Wif1), which is an inhibitor of Wnt-ß-catenin signaling. In Wif1(lacZ/lacZ) mutant mice and cultured urorectum with exogenous Wif1, cloaca septation was defective with undescended urs and hypospadias-like phenotypes, and such septation defects were also observed in Shh(-/-) mutants and in endodermal ß-catenin gain-of-function (GOF) mutants. In addition, Wif1 and Shh were expressed in a complementary manner in the cloaca endoderm, and Wif1 was ectopically expressed in the urs and cm associated with excessive endodermal apoptosis and septation defects in Shh(-/-) mutants. Furthermore, apoptotic cells were markedly reduced in the endodermal ß-catenin GOF mutant embryos, which counteracted the inhibitory effects of Wif1. Taken altogether, these data suggest that regulated expression of Wif1 is critical for the growth of the urs during cloaca septation. Hence, Wif1 governs cell apoptosis of urs endoderm by repressing ß-catenin signal, which may facilitate the protrusion of the underlying proliferating mesenchymal cells towards the cm for cloaca septation. Dysregulation of this endodermal Shh-Wif1-ß-catenin signaling axis contributes to ARM pathogenesis.

Management and prevention of spontaneous pneumothorax using pleurodesis in Hong Kong.

BACKGROUND: The practice of pleurodesis for the management and prevention of spontaneous pneumothorax (SP) is uncertain. DESIGN: A retrospective multicentre analysis of patients admitted to 12 hospitals in Hong Kong with SP in 2004 and who subsequently underwent pleurodesis for the same episode. RESULTS: Pleurodesis was performed in 394 episodes. Initial medical chemical pleurodesis was performed for 258 (65.5%) patients ('initial medical group'), while 136 (34.5%) underwent initial surgical pleurodesis ('initial surgical group'). Secondary spontaneous pneumothorax (SSP; 237 episodes, 60.2%) was the most common indication for pleurodesis; it was also performed after a first episode of primary spontaneous pneumothorax (PSP) in 22 episodes (5.6%). Tetracycline derivatives (172 episodes, 66.7%) were the most popular sclerosing agents in the initial medical group. Those in the initial medical group were older and were more likely to be males, have SSP, chronic obstructive pulmonary disease and a history of past pleurodesis (P < 0.05) compared to the initial surgical group. Compared to the tetracycline group, more patients who initially received talc slurry had the procedure performed by surgeons, had larger (≥2 cm) pneumothorax or required suction during initial drainage (P < 0.05). CONCLUSIONS: Despite the availability of international guidelines, there is considerable variation in pleurodesis for SP.

Minocycline and talc slurry pleurodesis for patients with secondary spontaneous pneumothorax.

SETTING: Few studies have evaluated the sclerosing efficacy of minocycline, and none have specifically compared its sclerosing efficacy and safety profiles with talc slurry in secondary spontaneous pneumothorax (SSP). DESIGN: A retrospective analysis was conducted in patients with SSP who underwent chemical pleurodesis from January to December 2004 with minocycline or talc slurry in 12 public hospitals of Hong Kong. RESULT: There were 121 episodes of minocycline pleurodesis and 64 episodes of talc slurry pleurodesis. Immediate procedural failure were similar in the minocycline and talc slurry groups (21.5% vs. 28.1%, P = 0.31). Presence of interstitial lung disease, ≥ 2 previous episodes of pneumothorax, requiring mechanical ventilation during pleurodesis and persistent air leak before pleurodesis were independently associated with procedural failure. Pain was experienced in respectively 44.6% and 37.5% of the minocycline and the talc slurry groups. Pain was more common in patients receiving high doses of talc (≥ 5 g; P = 0.03). Respiratory distress was found in respectively 1.7% and 1.6% of the minocycline and talc slurry groups. CONCLUSION: Minocycline and talc slurry had comparable sclerosing efficacy in SSP, with immediate success rates of >70%. Pain was the most common adverse effect and respiratory distress was uncommon. Both appeared to be effective and safe for chemical pleurodesis in SSP.

Elucidation of molecular and elementary composition of organic and inorganic substances involved in 19th century wax sculptures using an integrated analytical approach.

Wax sculptures contain several materials from both organic and inorganic nature. These works of art are particularly fragile. Determining their chemical composition is thus of prime importance for their preservation. The identification of the recipes of waxy pastes used through time also provides valuable information in the field of art history. The aim of the present research was to develop a convenient analytical strategy, as non-invasive as possible, that allows to identify the wide range of materials involved in wax sculptures. A multi-step analytical methodology, based on the use of complementary techniques, either non- or micro-destructive, was elaborated. X-ray fluorescence and micro-Raman spectroscopy were used in a non-invasive way to identify inorganic pigments, opacifiers and extenders. The combination of structural and separative techniques, namely infrared spectroscopy, direct inlet electron ionisation mass spectrometry and high temperature gas chromatography, was shown to be appropriate for unravelling the precise composition of the organic substances. A micro-chemical test was also performed for the detection of starch. From this study it has been possible to elucidate the composition of the waxy pastes used by three different sculptors at the end of the 19th century. Complex and elaborated recipes, in which a large range of natural substances were combined, were highlighted.

Interleukin-10 and its receptor.

The cytokine interleukin-10 (IL-10) has several important activities on cells of the immune system. IL-10 profoundly suppresses activation of macrophages, inhibiting their ability to secrete cytokines and serve as accessory cells for stimulation of T cell and natural killer (NK) cell function. IL-10 also plays a role in stimulating proliferation and differentiation of B cells, mast cells, and both mature and immature T cells. At least two herpesviruses harbor analogs of the IL-10 gene; the Epstein-Barr virus (EBV) homolog (BCRF1, viral IL-10, vIL-10) shares several of the cellular cytokine's activities, one or all of which may be important in the host-virus relationship. This article reviews recent studies on the function of IL-10 and discusses the initial characterization of its receptor.

Characterization of fimbriae produced by enteropathogenic Escherichia coli.

Enteropathogenic Escherichia coli (EPEC) express rope-like bundles of filaments, termed bundle-forming pili (BFP) (J. A. Girón, A. S. Y. Ho, and G. K. Schoolnik, Science 254:710-713, 1991). Expression of BFP is associated with localized adherence to HEp-2 cells and the presence of the EPEC adherence factor plasmid. In this study, we describe the identification of rod-like fimbriae and fibrillae expressed simultaneously on the bacterial surface of three prototype EPEC strains. Upon fimbrial extraction from EPEC B171 (O111:NM), three fimbrial subunits with masses of 16.5, 15.5, and 14.7 kDa were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Their N-terminal amino acid sequence showed homology with F9 and F7(2) fimbriae of uropathogenic E. coli and F1845 of diffuse-adhering E. coli, respectively. The mixture of fimbrial subunits (called FB171) exhibited mannose-resistant agglutination of human erythrocytes only, and this activity was not inhibited by alpha-D-Gal(1-4)-beta-Gal disaccharide or any other described receptor analogs for P, S, F, M, G, and Dr hemagglutinins of uropathogenic E. coli, which suggests a different receptor specificity. Hemagglutination was inhibited by extracellular matrix glycoproteins, i.e., collagen type IV, laminin, and fibronectin, and to a lesser extent by gangliosides, fetuin, and asialofetuin. Scanning electron microscopic studies performed on clusters of bacteria adhering to HEp-2 cells revealed the presence of structures resembling BFP and rod-like fimbriae linking bacteria to bacteria and bacteria to the eukaryotic cell membrane. We suggest a role of these surface appendages in the interaction of EPEC with eukaryotic cells as well as in the overall pathogenesis of intestinal disease caused by EPEC.