Cedar and cypress pollen counts are associated with the prevalence of allergic diseases in Japanese schoolchildren

BACKGROUND

Patients allergic to pollen have been known to become more symptomatic during pollen season compared with the nonpollen season. However, there are few studies regarding whether higher exposure to pollen might increase the prevalence of allergic diseases.

METHODS

An ecological analysis was conducted to evaluate whether pollen exposure is associated with the prevalence of allergic diseases in schoolchildren. Pollen count data of Japanese cedar (Cryptomeria japonica) and Japanese cypress (Chamaecyparis obtusa), which are the major pollen allergens in Japan, were obtained from each prefecture. The prevalence of allergic diseases in schoolchildren in each prefecture was based on a nationwide cross-sectional survey using the International Study of Asthma and Allergies in Childhood questionnaire.

RESULTS

After omitting three prefectures where pollen data were not available, data of 44 prefectures were analysed. The prevalence of allergic rhinoconjunctivitis in children aged 6-7 years was positively associated with both cedar and cypress pollen counts (P = 0.01, both), whereas the prevalence of allergic rhinoconjunctivitis in children aged 13-14 years was positively associated with only cypress pollen counts (P = 0.003). Furthermore, the prevalence of asthma was positively associated with cedar pollen counts in 6- to 7-year-old children (P = 0.003) but not cypress pollen counts in either age group.

CONCLUSIONS

There are ecological associations between pollen counts and the prevalence of allergic diseases in Japanese schoolchildren. Further studies are needed to determine whether the difference between the effects of cedar and cypress pollens is attributable to pollen counts or allergenicity.

Thymic stromal lymphopoietin expression is increased in the horny layer of patients with atopic dermatitis

Thymic stromal lymphopoietin (TSLP) is known for its capacity to induce CD11c(+) myeloid dendritic cells to promote T helper type 2 (Th2)-skewed inflammatory responses. Although increased expression of TSLP was reported in the lesional skin of limited numbers of patients with atopic dermatitis (AD), the relationships between the degree of TSLP expression in the skin and the severity of AD, epidermal barrier function and eruption type remain to be elucidated. The aim of this study was to examine the relationships between the degree of TSLP expression in the skin and the severity of AD, eruption type and epidermal barrier function using a non-invasive method in a sizeable group of the patients. Stratum corneum tissue was obtained from AD patients by tape stripping, and the stratum corneum TSLP (scTSLP) expression level was evaluated using a TSLP-specific antibody followed by image analysis. The correlations between the scTSLP intensity and the severity scoring of AD (SCORAD) index and epidermal barrier function, such as stratum corneum hydration and transepidermal water loss (TEWL), were analysed. The changes in the scTSLP level induced by the application of moisturizer were also examined. The scTSLP expression level was increased in AD patients compared with healthy subjects and was correlated with SCORAD, especially with the dry skin score, and stratum corneum hydration. Moisturizer application resulted in reduced scTSLP levels. The scTSLP level can be used as a biomarker of AD severity and particularly epidermal barrier status.

Usefulness of 3D DSA-MR fusion imaging in the pretreatment evaluation of brain arteriovenous malformations

RATIONALE AND OBJECTIVES

For the evaluation of patients scheduled for the treatment of brain arteriovenous malformations (AVMs), accurate anatomical information is essential. The purpose of this study was to assess the usefulness of three-dimensional (3D) digital subtraction angiography (DSA)-magnetic resonance (MR) fusion imaging for the pretreatment evaluation of AVMs.

MATERIALS AND METHODS

The study population consisted of 11 consecutive patients (7 males, 4 females; age 10-72 years; mean 45 years) with brain AVMs. All prospectively underwent pretreatment MR imaging (MRI), MR angiography (MRA), and two-dimensional (2D) and 3D DSA. The 3D DSA and MR images were semiautomatically fused with fusion software on a workstation. In the delineation of AVM nidus, feeder, drainer, and relationship between AVM and the adjacent brain structures, two radiologists independently evaluated MRA and MRI, three-dimensional (3D) DSA, and MRI, and 3D DSA-MR fusion images using a 4-point scoring system. The referring neurosurgeons were asked whether the information provided by 3D DSA-MR fusion images was helpful for treatment decisions.

RESULTS

For all four items, the delineation was significantly better with the 3D DSA/MRI or 3D DSA-MR fusion images than the MRA/MRI images. Although the delineation for the nidus, feeder, and drainer were not significantly different between the 3D DSA/MRI and 3D DSA-MR fusion images, 3D DSA-MR fusion imaging were significantly better for the relationship between AVM and the adjacent brain structures than 3D DSA/MR imaging (P = .0047). The information provided by 3D DSA-MR fusion images was helpful for treatment decisions in all cases.

CONCLUSION

3D DSA-MR fusion images are useful for the pretreatment evaluation of brain AVMs.

The analysis of the innate pathways of 5-fluorouracil phosphorylation in human gastrointestinal cancer cell lines in vitro and in vivo

Possible pathways of the phosphorylation of 5-fluorouracil (FUra) were investigated in vitro and in vivo, using certain xenografts, of human gastric and colorectal cancer cell lines. The oxonic acid (Oxo), an inhibitor of orotate phosphoribosyltransferase (OPRTase) that catalyzes the direct production of 5-fluorouridine 5'-monophosphate from FUra (the first pathway) and 2, 6-dihydroxypyridine (DP), an inhibitor of uridine phosphorylase (UPase), the enzyme converting FUra to 5-fluorouridine (the second pathway), were employed to estimate a contribution of these two metabolic pathways in the anabolism of FUra. Ten out of 13 cancer cell lines tested were found to utilize the first route for the phosphorylation of FUra, as revealed by marked inhibition of the phosphorylation of FUra by Oxo in 4 of 5 and in 6 of 8 gastric and colorectal cancer cell lines, respectively. The phosphorylation of FUra in the xenografts of human AZ521 gastric adenocarcinoma and SNU-C2A colorectal carcinoma was also regulated by Oxo, the production of 5-fluoro-nucleotides after i.v. injection of FUra with the Oxo significantly decreased from 0.587 to 0.311 nmol/g and from 1.75 to 0.40 nmol/g in respective xenografts, suggesting that the nature of an anabolic pathway of FUra in the tumor cells in vitro reflects the metabolic pattern found in the in vivo conditions. Moreover, the intracellular concentrations of phosphoribosylpyrophosphate (PPRibP) in DLD-1 and SNU-C(2)A cells were much higher than those found in HCT-15 and MKN-28 cells, leading to the findings that FUra was phosphorylated by OPRTase in the former and by UPase and uridine kinase in the latter cells. These results also may suggest that the intracellular levels of PPRibP in the tumor cells are importantly related to the selection of a proper metabolic pathway of FUra by the cell.

Energy filtering transmission electron microscopy immunocytochemistry and antigen retrieval of surface layer proteins from Tannerella forsythensis using microwave or autoclave heating with citraconic anhydride

Tannerella forsythensis (Bacteroides forsythus), an anaerobic Gram-negative species of bacteria that plays a role in the progression of periodontal disease, has a unique bacterial protein profile. It is characterized by two unique protein bands with molecular weights of more than 200 kDa. It also is known to have a typical surface layer (S-layer) consisting of regularly arrayed subunits outside the outer membrane. We examined the relationship between high molecular weight proteins and the S-layer using electron microscopic immunolabeling with chemical fixation and an antigen retrieval procedure consisting of heating in a microwave oven or autoclave with citraconic anhydride. Immunogold particles were localized clearly at the outermost cell surface. We also used energy-filtering transmission electron microscopy (EFTEM) to visualize 3, 3'-diaminobenzidine tetrahydrochloride (DAB) reaction products after microwave antigen retrieval with 1% citraconic anhydride. The three-window method for electron spectroscopic images (ESI) of nitrogen by the EFTEM reflected the presence of moieties demonstrated by the DAB reaction with horseradish peroxidase (HRP)-conjugated secondary antibodies instead of immunogold particles. The mapping patterns of net nitrogen were restricted to the outermost cell surface.

Identification and characterization of novel glycoproteins involved in growth and biofilm formation by Porphyromonas gingivalis

Porphyromonas gingivalis has been implicated as a major pathogen associated with chronic periodontitis. To extend our knowledge of post-translational protein glycosylation in P. gingivalis, a proteomic analysis involving two-dimensional polyacrylamide gel electrophoresis combined with carbohydrate staining and mass spectrometry was performed. Four novel glycoproteins, PGN0743, PGN0876, PGN1513 and PGN0729, in P. gingivalis ATCC 33277 were identified. These four identified glycoproteins possess a range of biochemical activities and cellular localization. PGN0743 contains a sequence motif identifying it as a FKBP-type cis-trans isomerase, which has activity usually associated with chaperone functions. PGN0876 and PGN1513 contain tetratricopeptide repeat domains that mediate protein-protein interactions. PGN0729 encodes the outer membrane protein 41 precursor, which was previously identified as Pgm6, and is homologous to the OmpA protein in Escherichia coli. Several different types of glycoprotein were identified, suggesting that P. gingivalis possesses a general mechanism for protein glycosylation. PGN0743-deficient and PGN0876-deficient mutants were constructed to examine the role(s) of the two identified glycoproteins. Both mutants showed a decreased growth rate under nutrient-limited conditions and reduced biofilm formation activity. These results suggest that the novel glycoproteins PGN0743 and PGN0876 play an important role in the growth and colonization of P. gingivalis.

SU-E-I-115: Wavelet Analysis of Ultrasound Image for the Diagnosis of Sjögren's Syndrome

PURPOSE

Sjögren's syndrome (SS) is an auto-immune disease presenting with dry eyes and mouth (keratoconjunctivitis sicca and xerostomia). Ultrasonography is used for the initial and non-invasive investigation of the parotid gland in the disease. The purpose of this study is to develop an image processing for diagnosis of SS by applying wavelet analysis to ultrasound image.

METHODS

Ultrasound B-mode images of the parotid gland were captured and analyzed by a personal computer. A square region of interest (ROI) was set on the image and two-dimensional discrete wavelet transform was performed within the ROI. As a Result, the image was decomposed into an approximate image and three detailed images in vertical, horizontal and diagonal directions in different scales. A feature quantity for image classification was defined by calculating from the wavelet coefficients of detailed images within selected scales. The ultrasound images of 80 patients who had been referred to Nagasaki University Hospital because of suspicion of SS were analyzed. A total of 37 patients fulfilled the criteria for SS, whereas the remaining 43 patients did not. The severity of SS was graded into four degrees by sialography. The images with each feature quantity were classified by statistical cluster analysis.

RESULTS

In this method, the images can be divided into two groups which mainly contained SS and non-SS. The sensitivity and specificity in the detection of SS was 78% and 95%, respectively. It was also found that the defined feature quantity tended to change with the severity of SS.

CONCLUSIONS

In ultrasonography, the image analysis based on wavelet transform was useful for the diagnosis of Sjögren's syndrome.

Characterization of multiple prompt gamma-ray analysis (MPGA) system at JAEA for elemental analysis of geological and cosmochemical samples

The newly installed multiple prompt gamma-ray analysis (MPGA) system at the Japan Atomic Energy Agency (JAEA) was characterized for nondestructive multi-element analysis of geological and cosmochemical samples. Analysis of the hydrogenous meteorite Orgueil by both MPGA and PGA implies that MPGA can be used for elemental determination with sufficient accuracy. For some elements which cannot be determined by conventional PGA due to the spectral interference or lower sensitivity, it was shown that they could be determined by MPGA.

Liver structures of a patient with idiopathic copper toxicosis

This is the first report describing the liver structures of a Japanese patient with idiopathic copper toxicosis, which should be differentiated from hepatolenticular degeneration of Wilson disease. An 11-year-old Japanese boy presented with ascites associated with biochemical liver damage. Involvement of hepatitis virus was ruled out by laboratory tests. Because urinary copper excretion was increased, Wilson disease was highly suspected, but the serum level of ceruloplasmin was normal, and Kayser-Fleischer rings were not detected by slit lamp examination. Brain images were within normal limits. ATP7B analysis was negative for mutations. Liver specimen showed cirrhosis associated with chronic active hepatitis. Almost all hepatocytes were positive for orcein-stained granules. Mallory bodies were found in some hepatocytes. Fatty change was minimal, and there were no glycogenated nuclei in the parenchyma. Combined regimens of trientine and zinc for 6 months improved the decompensated state of liver function. After 2.5 years of treatment, a second liver biopsy was performed. The post-treatment liver showed complete disappearance of portal inflammation and remarkable decrease in cuprothionein granules. Mallory bodies disappeared from the parenchyma. An abundance of hepatocellular Mallory bodies and heavy copper loading limited to the liver may be specific to idiopathic copper toxicosis.

Origin of the large polarization in multiferroic YMnO3 thin films revealed by soft- and hard-X-ray diffraction

We investigated the magnetic structure of an orthorhombic YMnO(3) thin film by resonant soft x-ray and hard x-ray diffraction. We observed a temperature-dependent incommensurate magnetic reflection below 45 K and a commensurate lattice-distortion reflection below 35 K. These results demonstrate that the ground state is composed of coexisting E-type and cycloidal states. Their different ordering temperatures clarify the origin of the large polarization to be caused by the E-type antiferromagnetic states in the orthorhombic YMnO(3) thin film.

Peierls mechanism of the metal-insulator transition in ferromagnetic hollandite K2Cr8O16

Synchrotron x-ray diffraction experiment shows that the metal-insulator transition occurring in a ferromagnetic state of a hollandite K(2)Cr(8)O(16) is accompanied by a structural distortion from the tetragonal I4/m to monoclinic P112(1)/a phase with a √2×√2×1 supercell. Detailed electronic structure calculations demonstrate that the metal-insulator transition is caused by a Peierls instability in the quasi-one-dimensional column structure made of four coupled Cr-O chains running in the c direction, leading to the formation of tetramers of Cr ions below the transition temperature. This provides a rare example of the Peierls transition of fully spin-polarized electron systems.

Displacement-type ferroelectricity with off-center magnetic ions in perovskite Sr(1-x)Ba(x)MnO3

We report a ferroelectric transition driven by the off-centering of magnetic Mn(4+) ions in antiferromagnetic Mott insulators Sr(1-x)Ba(x)MnO(3) with a perovskite structure. As x increases, the perovskite lattice shows the typical soft-mode dynamics, as revealed by the momentum-resolved inelastic x-ray scattering and far-infrared spectroscopy, and the ferroelectricity shows up for x ≥ 0.45. The observed polarization is comparable to that for a prototypical ferroelectric BaTiO(3). We further demonstrate that the magnetic order suppresses the ferroelectric lattice dilation by ∼70% and increases the soft-phonon energy by ∼50%, indicating the largest magnetoelectric effects yet attained.

OmpA-like protein influences cell shape and adhesive activity of Tannerella forsythia

Tannerella forsythia, a gram-negative fusiform rod, is implicated in several types of oral anaerobic infections. Most gram-negative bacteria have OmpA-like proteins that are homologous to the OmpA protein in Escherichia coli. We identified an OmpA-like protein in T. forsythia encoded by the tf1331 gene as one of the major proteins by mass spectrometric analysis. Two-dimensional, diagonal electrophoresis showed that the OmpA-like protein formed a dimeric or trimeric structure via intermolecular disulfide bonds. A biotin labeling experiment revealed that a portion of the protein was exposed on the cell surface, even though T. forsythia possesses an S-layer at the outermost cell surface. Using a tf1331-deletion mutant, we showed that the OmpA-like protein affected cell morphology. The length of the mutant cell was reduced almost by half. Cell swelling was observed in more than 40% of the mutant cells. Moreover, the mutant exhibited decreased adhesion to fibronectin, retarded autoaggregation, and reduced cell surface hydrophobicity. These results suggest that the OmpA-like protein in T. forsythia plays an important role in cellular integrity and adhesive function.

Giant Rashba-type spin splitting in bulk BiTeI

There has been increasing interest in phenomena emerging from relativistic electrons in a solid, which have a potential impact on spintronics and magnetoelectrics. One example is the Rashba effect, which lifts the electron-spin degeneracy as a consequence of spin-orbit interaction under broken inversion symmetry. A high-energy-scale Rashba spin splitting is highly desirable for enhancing the coupling between electron spins and electricity relevant for spintronic functions. Here we describe the finding of a huge spin-orbit interaction effect in a polar semiconductor composed of heavy elements, BiTeI, where the bulk carriers are ruled by large Rashba-like spin splitting. The band splitting and its spin polarization obtained by spin- and angle-resolved photoemission spectroscopy are well in accord with relativistic first-principles calculations, confirming that the spin splitting is indeed derived from bulk atomic configurations. Together with the feasibility of carrier-doping control, the giant-Rashba semiconductor BiTeI possesses excellent potential for application to various spin-dependent electronic functions.

Is patella eversion during total knee arthroplasty crucial for gap adjustment and soft-tissue balancing?

INTRODUCTION

Assessment of soft-tissue balance by the gap technique in Total Knee Arthroplasty (TKA) impacts femoral component rotation positioning. Proper femoral component rotation is a critical factor in TKA, both for adequate patellar tracking and in achieving a symmetrical flexion gap. Soft tissue balance assessment and gap measurements are performed at 90° flexion and with the patella everted in conventional TKA; during MIS-TKA, this step is performed with the patella in situ. We therefore investigated intraoperative joint gap parameters at 90° flexion with and without patellar eversion during conventional TKA, so as to better understand the influence of this intraoperative patellar position factor on final ligament balance.

HYPOTHESIS

Conducting TKA without patellar eversion increases both gap size and gap inclination.

PATIENTS AND METHODS

Twenty-four osteoarthritic knees were included in the study. Joint gap size and inclination were measured intraoperatively on a knee in 90° flexion, with and without patellar eversion.

RESULTS

The joint gap with patella in situ (17.0±3.4 mm) was significantly greater than with patellar eversion (15.4±3.0 mm), as was gap inclination at 90° flexion with the patella in situ (4.9±3.1°) compared to with patellar eversion (4.0±2.9°).

DISCUSSION

The flexion gap inclination obtained without patellar eversion was steeper than with patellar eversion. This induced more externally rotated femoral positioning in absence of patellar eversion. These results ought to be taken into account by surgeons considering switching from conventional to MIS-TKA.

Maternal stress affects postnatal growth and the pituitary expression of prolactin in mouse offspring

Maternal stress exerts long-lasting psychiatric and somatic on offspring, which persist into adulthood. However, the effect of maternal stress on the postnatal growth of pups has not been widely reported. In this study, we found that maternal immobilization stress (IS) during lactation resulted in low body weight of male mouse offspring, which persisted after weaning. Despite free access to chow, IS induced maternal malnutrition and decreased the serum insulin-like growth factor-1 (IGF-1) levels in the mothers and in the pups. mRNA expression analysis of anterior pituitary hormones in the pups revealed that growth hormone (GH) and prolactin (PRL), but no other hormones, were decreased by IS. Expression of the pituitary transcription factor PIT1 and isoforms of PITX2, which are essential for the development and function of GH-producing somatotropes and PRL-producing lactotropes, was decreased, whereas that of PROP1, which is critical for the earlier stages of pituitary development, was unchanged. Immunohistochemistry also showed a decrease in pituitary PRL protein expression. These results suggest that stress in a postpartum mother has persistent effects on the body weight of the offspring. Reduced PRL expression in the offspring's pituitary gland may play a role in these effects.

Crystal Structure of Endohedral Metallofullerene La@C82

Since the success of synthesis the molecular structure of the endohedral metallofullerene is a most interesting subject in relation to the electronic state of metal and carbon cage. Highquality crystals of endohedral metallofullerene La@C82 have been synthesized by the arc discharge and HPLC method. The x-ray powder diffraction and the precession photograph of a tiny single crystal have revealed the cubic structure with the space group I43d and the lattice constant ao = 25.72 ± 0.007 Å at room temperature. The structure is characterized by the molecular arrangement in which the molecules align in the [111] direction with the molecular axis orienting in the same [111] direction; this structure suggests the existence of a dipole interaction between the molecules. The metal position in the cage is also discussed on the basis of an ellipsoidal model of molecule.

Outcomes of chemoradiotherapy with a high irradiation dose using a 3D radiation treatment planning system for esophageal cancer

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Background: The standard irradiation dose of chemoradiotherapy (CRT) for esophageal cancer is 50.4 Gy, however, the trials in which this standard dose was originated were based on 2D radiation treatment planning. In this study we assessed the survival and toxicities of CRT with a dose of 60-66 Gy using a 3D radiation treatment planning system (3DRTPS) for esophageal cancer.

Methods: One hundred and two eligible patients with esophageal cancer treated by definitive CRT between 2000 and 2006 were assessed. Median age was 67 years old. There were stage I in 22 patients, stage II-III (without T4) in 27 and T4/M1Lymph legions in 53. There were 100 patients with squamous cell carcinoma histology and 2 with small cell carcinoma. Main tumor sites were cervical/upper/middle/lower thoracic in 15/19/43/25 patients. Treatment planning of irradiation was performed using a CT based 3DRTPS. Total irradiation dose of our protocol was 60-66 Gy. Accomplishment rate of planned irradiation was 93%. All patients received chemotherapy concurrently with radiotherapy. Fluorouracil based chemotherapy was performed in 96 patients (94%).

Results: The data was updated in August 2010. The median follow-up was 67 months. Cause-specific survival rates at 5 years for stage I, II-III (without T4) and T4/M1lymph were 100%, 49% and 17%, respectively and overall survival rates were 66%, 35% and 13%, respectively. Complete response (CR) rates were 100%, 79% and 35%, respectively and failure rates of CR cases were 5%, 43% and 42%, respectively. Late adverse effects (≥ grade 3) were observed in 11 patients (10%); pneumonitis in 4 (4%), pleural effusion in 4 (4%) and pericardial effusion in 5 (5%). Treatment related deaths were observed in 2 cases (pneumonitis developed during treatment in 1 and debility due to treatment in 1).

Conclusions: Toxicities of CRT with a high irradiation dose using 3DRTPS for esophageal cancer were acceptable and survival was promising. Dose intensification study of 50.4 Gy versus ≥ 60 Gy in CRT using a 3D-conformal radiation therapy technique for esophageal cancer should be considered.

No significant financial relationships to disclose.

Self-organized nanodot pattern fabrication using the reverse sputtering method

We demonstrate the synthesis of high density periodic 2D nanodot patterns using reverse sputtering in magnetron sputtering equipment on a single crystal Si substrate and sputter-deposited Si-thin film. In this etching process, a minute amount of Ta is supplied by DC sputtering or splashing from the substrate holder surface. STEM, EDX, TEM and XPS analyses confirmed preferentially localized Ta-silicide in the nanodots. The nanodot pattern formation is attributed to the repeated adsorption and desorption of Ta and Si molecules forming Ta-silicide, and its segregation with self-organization. We also discuss power and time dependence of the nanodot pattern sizes and hole structure formation as a side-effect. This simple process is conducted at room temperature and makes use of an extremely simple setup. Our result promises a significant improvement in the productivity of quantum dot devices and has the potential to trigger their worldwide spread.

Stratum corneum TARC level is a new indicator of lesional skin inflammation in atopic dermatitis

BACKGROUND

Management of atopic dermatitis (AD) requires judging the symptoms of local skin lesions and prescribing a suitable treatment. However, no method has been established in which objective measures can be used to evaluate the severity of local symptoms. We established a method for measuring thymus and activation-regulated chemokine (TARC) levels in the stratum corneum (scTARC), and examined whether the scTARC can be used as an indicator of the severity of local skin lesions in patients with AD.

METHODS

Stratum corneum was obtained from patients with AD by tape-stripping, and scTARC was evaluated using a TARC-specific antibody followed by image analysis. The scTARC was examined to determine correlation with the severity of local skin lesions (the severity of erythema, edema/papule, oozing/crusts, excoriations, lichenification, and xerosis) as well as with the severity scoring of atopic dermatitis (SCORAD) index, serum TARC level, serum IgE level, serum lactate dehydrogenase (LDH) level, interleukin (IL)-4-producing T cell ratio (Th2 cell ratio), and blood eosinophil count.

RESULTS

The scTARC was correlated with the severity of local skin lesions, especially with the erythema, edema/papule, and oozing/crusts score. The scTARC in the most severe lesions was also correlated with the SCORAD index, serum TARC level, serum IgE level, and blood eosinophil count. The scTARC was not, however, correlated with the serum LDH level and Th2 cell ratio.

CONCLUSION

An immunofluorescent technique combined with tape-stripping was used to measure scTARC. The scTARC can be used as an indicator of the severity of local acute inflammation in patients with AD.

Exciton diffusion in air-suspended single-walled carbon nanotubes

Direct measurements of the diffusion length of excitons in air-suspended single-walled carbon nanotubes are reported. Photoluminescence microscopy is used to identify individual nanotubes and to determine their lengths and chiral indices. Exciton diffusion length is obtained by comparing the dependence of photoluminescence intensity on the nanotube length to numerical solutions of diffusion equations. We find that the diffusion length in these clean, as-grown nanotubes is significantly longer than those reported for micelle-encapsulated nanotubes.

FimB regulates FimA fimbriation in Porphyromonas gingivalis

The periodontitis-associated pathogen Porphyromonas gingivalis colonizes and forms a biofilm in gingival crevices through fimbriae. It is known that the often-used strains ATCC 33277 and 381 produce long FimA fimbriae. We found a possible nonsense mutation within fimB, immediately downstream from fimA, coding a major subunit of FimA fimbriae of the strains. Indeed, P. gingivalis strains, except for ATCC 33277 and 381, universally expressed FimB, the gene product of fimB. Electron micrographs revealed that a FimB-restored strain had short and dense, "toothbrush"-like, FimA fimbriae. FimA overexpression elongated the fimbriae, whereas FimB overexpression shortened them. FimB restoration increased production of FimA and its accessory proteins. Thus, FimB regulates the length and expression of FimA fimbriae. Additionally, FimB restoration significantly reduced the release of FimA fimbriae from the cell surface, suggesting that FimB functions as an anchor of the fimbriae. The restoration enhanced adherent activity as well.