Fast rebinding increases dwell time of Src homology 2 (SH2)-containing proteins near the plasma membrane

Receptor tyrosine kinases (RTKs) control a host of biological functions by phosphorylating tyrosine residues of intracellular proteins upon extracellular ligand binding. The phosphotyrosines (p-Tyr) then recruit a subset of ～100 Src homology 2 (SH2) domain-containing proteins to the cell membrane. The in vivo kinetics of this process are not well understood. Here we use total internal reflection (TIR) microscopy and single-molecule imaging to monitor interactions between SH2 modules and p-Tyr sites near the cell membrane. We found that the dwell time of SH2 modules within the TIR illumination field is significantly longer than predictions based on chemical dissociation rate constants, suggesting that SH2 modules quickly rebind to nearby p-Tyr sites after dissociation. We also found that, consistent with the rebinding model, the effective diffusion constant is negatively correlated with the respective dwell time for different SH2 domains and the dwell time is positively correlated with the local density of RTK phosphorylation. These results suggest a mechanism whereby signal output can be regulated through the spatial organization of multiple binding sites, which will prompt reevaluation of many aspects of RTK signaling, such as signaling specificity, mechanisms of spatial control, and noise suppression.     

Ameloblastoma, desmoplastic type: a case report with characteristic radiological presentation

Ameloblastoma, desmoplastic type, is a rare lesion for which radiographic images are even less common, and such lesions are sometimes considered to be variant types. It is defined as a variant of ameloblastoma with specific imaging and histological features. This lesion occurs with the same frequency in the maxilla and mandible, although the predominant site is the anterior-premolar site in both the mandible and maxilla. For our case of ameloblastoma, desmoplastic type, resected from the right anterior to premolar maxilla, the radiographic appearance and histopathological findings were compared. Computed tomography images revealed that the lesion had a multilocular structure with many smaller septa at its periphery. Although expansion toward the maxillary sinus was suggested radiologically, invasion of the mucosa into the floor of the maxillary sinus was found on histopathological examination.     

Extensive gene deletions in Japanese patients with Diamond-Blackfan anemia

Fifty percent of Diamond-Blackfan anemia (DBA) patients possess mutations in genes coding for ribosomal proteins (RPs). To identify new mutations, we investigated large deletions in the RP genes RPL5, RPL11, RPL35A, RPS7, RPS10, RPS17, RPS19, RPS24, and RPS26. We developed an easy method based on quantitative-PCR in which the threshold cycle correlates to gene copy number. Using this approach, we were able to diagnose 7 of 27 Japanese patients (25.9%) possessing mutations that were not detected by sequencing. Among these large deletions, similar results were obtained with 6 of 7 patients screened with a single nucleotide polymorphism array. We found an extensive intragenic deletion in RPS19, including exons 1-3. We also found 1 proband with an RPL5 deletion, 1 patient with an RPL35A deletion, 3 with RPS17 deletions, and 1 with an RPS19 deletion. In particular, the large deletions in the RPL5 and RPS17 alleles are novel. All patients with a large deletion had a growth retardation phenotype. Our data suggest that large deletions in RP genes comprise a sizable fraction of DBA patients in Japan. In addition, our novel approach may become a useful tool for screening gene copy numbers of known DBA genes.     

Power Doppler ultrasonography is useful for assessing disease activity and predicting joint destruction in rheumatoid arthritis patients receiving tocilizumab—preliminary data

To evaluate the responsiveness of power Doppler ultrasonography (PDUS) in comparison with conventional measures of disease activity and structural damage in rheumatoid arthritis (RA) patients receiving tocilizumab (TCZ). Seven RA patients with active arthritis were enrolled in the study and prospectively monitored for 12 months. They were treated with TCZ (8 mg/kg) every 4 weeks as monotherapy or in combination with disease-modifying antirheumatic drugs (DMARDs). Clinical, laboratory, and ultrasound examinations were conducted at baseline, 1, 3, 6, 9, and 12 months. Power Doppler (PD) signals were graded from 0 to 3 in 24 joints, and total PD score was calculated as the sum of scores of individual joints. One-year radiographic progression of the hands was estimated by using Genant-modified Sharp scoring. The averages of the clinical parameters rapidly improved, and all patients achieved good response within 6 months based on standard 28-joint Disease Activity Score (DAS28). Although the average total PD score declined in parallel with clinical improvement, radiography of the hands showed progression of destruction in the joints where PD signals remained, even among clinical responders. ΔSharp score correlated with the time-integrated value (TIV) of total PD scores (Δtotal Sharp score: r = 0.77, P = 0.04; Δerosion: r = 0.78, P = 0.04; Δjoint-space narrowing (JSN): r = 0.75, P = 0.05), but not with TIVs of clinical parameters including DAS28. PDUS can independently evaluate disease activity in RA patients receiving TCZ and is superior to DAS28, especially in predicting joint destruction.     

Relationship between depression and risk of malnutrition among community-dwelling young-old and old-old elderly people

Objectives: This study explores the association between nutritional status and depression among healthy community-dwelling young-old (aged 65–74) and old-old elderly (aged 75 and older).

Method: A cross-sectional design was implemented. A total of 274 community-dwelling older individuals (142 young-old; 132 old-old) were assessed using the Geriatric Depression Scale (GDS), Mini-Nutritional Assessment Short-Form (MNA-SF) and Life-Space Assessment. Logistic regression analysis was used to determine if depression was independently associated with risk of malnutrition, stratified by age (young-old vs. old-old).

Results: In the logistic regression model for young-old, being at risk of malnutrition (MNA-SF (≦11) was strongly associated with depression (GDS (≧5;) (likelihood ratio ν?=?6.26; 95% confidence interval [CI]: 1.91–20.49). In contrast, in the old-old group, the model was not statistically significant.

Conclusion: Depression and nutritional status were strongly correlated in young-old but not in old-old community-dwelling elderly. This study reveals that not only the factors correlated with but also the symptoms of depression may vary among different age stratifications of the elderly.     

Characterization of twenty-four polymorphic microsatellite loci of Rasbora borapetensis

Twenty-four microsatellite loci were isolated and characterized from the genome of Rasbora borapetensis. Flanking polymerase chain reaction primers were designed and used to amplify these loci in 32 individuals. All loci were polymorphic with allele numbers ranging from 2 to 27, observed heterozygosity from 0.031 to 1.000 and expected heterozygosity from 0.031 to 0.965. All loci conformed to the Hardy–Weinberg equilibrium and no evidence of null alleles was observed. Pairwise comparisons between alleles did not detect any linkage disequilibrium. The high level of polymorphisms observed in these microsatellite loci will enhance future investigations on the genetic differentiation and structure of populations of Rasbora borapetensis.     

Cone-beam computed tomography for the diagnosis of mandibular condylar fractures: 11 case reports

The temporomandibular joint has many complex anatomical and functional features compared with other joints. Therefore, caution should be exercised in the diagnosis of temporomandibular joint fractures. Although panoramic tomography is widely used for the screening of orofacial trauma as well as other diseases, this modality often overlooks evidence of a condylar fracture. Cone-beam computed tomography is also used for diagnosing orofacial diseases. The purposes of this report are to show the usefulness of cone-beam computed tomography in diagnosing condylar fractures and to describe the imaging features of condylar fractures.     

Improved techniques for double-balloon-enteroscopy-assisted endoscopic retrograde cholangiopancreatography

AIM: To investigate the clinical outcome of double balloon enteroscopy (DBE)-assisted endoscopic retrograde cholangiopancreatography (DB-ERCP) in patients with altered gastrointestinal anatomy.METHODS: Between September 2006 and April 2011, 47 procedures of DB-ERCP were performed in 28 patients with a Roux-en-Y total gastrectomy (n = 11), Billroth II gastrectomy (n = 15), or Roux-en-Y anastomosis with hepaticojejunostomy (n = 2). DB-ERCP was performed using a short-type DBE combined with several technical innovations such as using an endoscope attachment, marking by submucosal tattooing, selectively applying contrast medium, and CO₂ insufflations.RESULTS: The papilla of Vater or hepaticojejunostomy site was reached in its entirety with a 96% success rate (45/47 procedures). There were no significant differences in the success rate of reaching the blind end with a DBE among Roux-en-Y total gastrectomy (96%), Billroth II reconstruction (94%), or pancreatoduodenectomy (100%), respectively (P = 0.91). The total successful rate of cannulation and contrast enhancement of the target bile duct in patients whom the blind end was reached with a DBE was 40/45 procedures (89%). Again, there were no significant differences in the success rate of cannulation and contrast enhancement of the target bile duct with a DBE among Roux-en-Y total gastrectomy (88 %), Billroth II reconstruction (89%), or pancreatoduodenectomy (100%), respectively (P = 0.67). Treatment was achieved in all 40 procedures (100%) in patients whom the contrast enhancement of the bile duct was successful. Common endoscopic treatments were endoscopic biliary drainage (24 procedures) and extraction of stones (14 procedures). Biliary drainage was done by placement of plastic stents. Stones extraction was done by lithotomy with the mechanical lithotripter followed by extraction with a basket or by the balloon pull-through method. Endoscopic sphincterotomy was performed in 14 procedures with a needle precutting knife using a guidewire. The mean total duration of the procedure was 93.6 ± 6.8 min and the mean time required to reach the papilla was 30.5 ± 3.7 min. The mean time required to reach the papilla tended to be shorter in Billroth II reconstruction (20.9 ± 5.8 min) than that in Roux-en-Y total gastrectomy (37.1 ± 4.9 min) but there was no significant difference (P = 0.09). A major complication occurred in one patient (3.5%); perforation of the long limb in a patient with Billroth II anastomosis.CONCLUSION: Short-type DBE combined with several technical innovations enabled us to perform ERCP in most patients with altered gastrointestinal anatomy.