Direct covalent bond formation between materials using copper(i)-catalyzed azide alkyne cycloaddition reactions

Bondings between polymeric materials and between polymeric materials and inorganic glass substrates have been achieved using the CuAAC reaction.

[No recurrent case of the combination of surgical management with chemotherapy]

A 61-year-old man consulted a nearby doctor with the chief complaint of lassitude in June 2010. Blood tests revealed a hemoglobin level of 3.7 g/dL. The observation of significant anemia resulted in a full medical workup. On computed tomography (CT) findings, a large mass (17 × 10 cm in diameter) was found in the abdominal region. The lumen was distended with accumulation of air and fluid. In addition, I continued with a bladder wall, but did not recognize the abnormality that was apparent to a bladder lumen. There was no evidence of ileus. A diagnosis of appendix cancer or sarcoma was made preoperatively. During surgery, the bladder was observed to have some permeation, but the bladder wall contained a lesion of small intestinal origin with only slight permeation. The neighboring small intestine was surrounded by the tumor, with 3 sites of penetration. Histopathologic diagnosis indicated a high-risk gastrointestinal stromal tumor (GIST) with mitotic figures (44/50 high power fields). In accordance with the recommended guidelines, imatinib was administered for 1 year. Two sites of recurrences were observed by CT after discontinuing imatinib. A second operation was performed without increase because of the absence other lesions. Separate lesions in the sigmoid colon and jejunum were removed surgically. The tumor in the sigmoid colon was a lesion with high denaturation for mesenchymal system tumor such as GISTs by pathologic diagnosis. The lesion in the small mesentery was a suture granuloma. In this case, the combination of surgical management with chemotherapy resulted in good quality of life with no recurrence despite the presence of a high-risk GIST.

A metal-ion-responsive adhesive material via switching of molecular recognition properties

Common adhesives stick to a wide range of materials immediately after they are applied to the surfaces. To prevent indiscriminate sticking, smart adhesive materials that adhere to a specific target surface only under particular conditions are desired. Here we report a polymer hydrogel modified with both β-cyclodextrin (βCD) and 2,2'-bipyridyl (bpy) moieties (βCD-bpy gel) as a functional adhesive material responding to metal ions as chemical stimuli. The adhesive property of βCD-bpy gel based on interfacial molecular recognition is expressed by complexation of metal ions to bpy that controlled dissociation of supramolecular cross-linking of βCD-bpy. Moreover, adhesion of βCD-bpy gel exhibits selectivity on the kinds of metal ions, depending on the efficiency of metal-bpy complexes in cross-linking. Transduction of two independent chemical signals (metal ions and host-guest interactions) is achieved in this adhesion system, which leads to the development of highly orthogonal macroscopic joining of multiple objects.

Supramolecular polymeric materials via cyclodextrin-guest interactions

CONSPECTUS: Cyclodextrins (CDs) have many attractive functions, including molecular recognition, hydrolysis, catalysis, and polymerization. One of the most important uses of CDs is for the molecular recognition of hydrophobic organic guest molecules in aqueous solutions. CDs are desirable host molecules because they are environmentally benign and offer diverse functions. This Account demonstrates some of the great advances in the development of supramolecular materials through host-guest interactions within the last 10 years. In 1990, we developed topological supramolecular complexes with CDs, polyrotaxane, and CD tubes, and these preparation methods take advantage of self-organization between the CDs and the polymers. The combination of polyrotaxane with αCD forms a hydrogel through the interaction of αCDs with the OH groups on poly(ethylene glycol). We categorized these polyrotaxane chemistries within main chain type complexes. At the same time, we studied the interactions of side chain type supramolecular complexes with CDs. In these systems the guest molecules modified the polymers and selectively formed inclusion complexes with CDs. The systems that used low molecular weight compounds did not show such selectivity with CDs. The multivalency available within the complex cooperatively enhances the selective binding of CD with guest molecules via the polymer side chains, a phenomenon that is analogous to binding patterns observed in antigen-antibody complexes. To incorporate the molecular recognition properties of CDs within the polymer side chains, we first prepared stimuli-responsive sol-gel switching materials through host-guest interactions. We chose azobenzene derivatives for their response to light and ferrocene derivatives for their response to redox conditions. The supramolecular materials were both redox-responsive and self-healing, and these properties resulted from host-guest interactions. These sol-gels with built in switches gave us insight for creating materials that were self-healing or could serve as artificial muscle. Furthermore, we developed another self-healing material with CD inclusion complexes that showed selective self-healing properties after its surface was cut. These CD self-healing materials do not include chemical cross-linkers; instead the inclusion complex of CDs with guest molecules stabilized the material's strength. However, by introducing chemical cross-linkers into the hydrogels, we produced materials that could expand and contract. The chemical cross-linked hydrogels with responsive groups bent in response to external stimuli, and the cross-linkers controlled the ratio of inclusion complexes. Furthermore, we used the molecular recognition of CDs to achieve macroscopic self-assemblies, and this chemistry can direct these macroscopic objects into even larger aggregated structures. As we have demonstrated, reversible host-guest interactions have tremendous potential for the creation of a wide variety of functional materials.

pH- and Sugar-Responsive Gel Assemblies Based on Boronate-Catechol Interactions

The interaction between poly(acrylamide) gels carrying phenylboronic acid (PB gel) and catechol moieties (CAT gel) respectively is investigated. The PB gel forms an assembly with the CAT gel on a macroscopic scale in basic aqueous media. The adhesion strength is estimated by stress-strain measurements. The assembly and disassembly of the gels are reversibly switched by varying the pH of the medium. The adhesion strength is tunable by competitive monosaccharide molecules in accordance with the association constant with PB moieties.

Association of the C–509→T polymorphism, alone or in combination with the T869→C polymorphism, of the transforming growth factor-β1 gene with bone mineral density and genetic susceptibility to osteoporosis in Japanese women

Transforming growth factor-beta1 is an important local regulator of bone metabolism, acting downstream of estrogen and cooperatively with vitamin D. The possible association of a C 509-->T polymorphism in the promoter region of the transforming growth factor-beta1 gene, alone or in combination with a T869-->C (Leu10-->Pro) polymorphism, with bone mineral density and genetic susceptibility to osteoporosis was investigated in 625 postmenopausal Japanese women. The frequencies of the CC, CT, and TT genotypes of the C-509-->T polymorphism in the study population were 24%, 49%, and 27%, respectively. A significant association of C-509-->T genotype with bone mineral density was detected: lumbar spine (L2-L4) and total body bone mineral density values were 7% and 5% lower, respectively, in individuals with the TT genotype than in those with the CT or CC genotype. The serum concentration of transforming growth factor-beta1 did not vary with C-509-->T genotype. Multivariable logistic regression analysis, with adjustment for age, height, body weight, time since menopause, smoking status, body fat mass, and lean mass, revealed a significantly higher frequency of the TT genotype of the C-509-->T polymorphism in 286 individuals with osteoporosis than in 170 normal controls. Analysis of combined C-509-->T and T869-->C genotypes showed that L2-L4 bone mineral density decreases and the prevalence of osteoporosis increases with the number of T alleles. These results suggest that the C-509-->T polymorphism, alone or in combination with the T869-->C polymorphism, of the transforming growth factor-beta1 gene is a genetic determinant of bone mass, and that the number of T alleles in the combined genotype is a risk factor for the genetic susceptibility to osteoporosis in postmenopausal Japanese women.

Classification of women with and without hip fracture based on quantitative computed tomography and finite element analysis

We used quantitative computed tomography and finite element analysis to classify women with and without hip fracture. Highly accurate classifications were achieved indicating the potential for these methods to be used for subject-specific assessment of fracture risk.

INTRODUCTION

Areal bone mineral density (aBMD) is the current clinical diagnostic standard for assessing fracture risk; however, many fractures occur in people not defined as osteoporotic by aBMD. Finite element (FE) analysis based on quantitative computed tomography (QCT) images takes into account both bone material and structural properties to provide subject-specific estimates of bone strength. Thus, our objective was to determine if FE estimates of bone strength could classify women with and without hip fracture.

METHODS

Twenty women with femoral neck fracture and 15 women with trochanteric fractures along with 35 age-matched controls were scanned with QCT at the hip. Since it is unknown how a specific subject will fall, FE analysis was used to estimate bone stiffness and bone failure load under loading configurations with femoral neck internal rotation angles ranging from -30° to 45° with 15° intervals. Support vector machine (SVM) models and a tenfold cross-validation scheme were used to classify the subjects with and without fracture.

RESULTS

High accuracy was achieved when using only FE analysis for classifying the women with and without fracture both when the fracture types were pooled (82.9 %) and when analyzed separately by femoral neck fracture (87.5 %) and trochanteric fracture (80.0 %). The accuracy was further increased when FE analysis was combined with volumetric BMD (pooled fractures accuracy, 91.4 %)

CONCLUSIONS

While larger prospective studies are needed, these results demonstrate that FE analysis using multiple loading configurations together with SVM models can accurately classify individuals with previous hip fracture.

A New Grip Strength Measuring Device for Detailed Evaluation of Muscle Contraction among the Elderly

BACKGROUND

We developed a new grip strength measuring device, which considers the time axis, for evaluating muscle contraction in detail in elderly people.

OBJECTIVES

To present the novel device and preliminary results concerning agility in gripping.

DESIGN

Cross-sectional analysis.

PARTICIPANTS

One hundred and twenty-one older persons (48 men and 73 women, mean age 74.4 years) referring for memory disorders to the outpatient clinic of our institute.

MEASUREMENTS

A novel device taking advantage of an industrial force-gauge was developed for measuring gripping performance. The instrument graphically described participants' strength production. Nine indices were derived from four points identified by the graph: 1) starting point ("Go signal"), 2) time when gripping starts, 3) turning point (TP) when the inclination of the curve depicting strength production changes, and 4) peak of strength production. Results obtained from the study sample of older persons were compared (as ratios) to a control group of 30 healthy young adults in their thirties in order to calculate age-related decline rates. Differences between right and left side were compared.

RESULTS

A significant difference was observed between right and left hands concerning the time to reach peak of strength, and time from TP to strength peak in both men and women. For women, the following indices were also significantly different: time to reach TP, strength at TP, time from TP to strength peak, curve inclination from TP to strength peak, and ratio of TP strength divided by peak strength.

CONCLUSION

Declines in several indices of gripping agility were measured. The parameters which were more closely related to time than strength itself showed significant differences between right and left hands, especially in women.

Cyclodextrin-based molecular machines

This chapter overviews molecular machines based on cyclodextrins (CDs). The categories of CD-based molecular machines, external stimuli for CD-based molecular machines, and typical examples of CD-based molecular machines are briefly described.

Deep vein thrombosis in patients with severe motor and intellectual disabilities

Most patients with severe motor and intellectual disabilities (SMID) have restricted mobility capability and have been bedridden for long periods because of paralysis of the extremities caused by abnormal muscular tonicity due to cerebral palsy and developmental disabilities, and such patients are associated with a high risk for the complications of deep vein thrombosis (DVT). Here, we report 8 patients (34.8%) with DVT among 23 patients with SMID during prolonged bed rest. However, we did not detect thrombosis in the soleal veins, finding it mostly in the superficial femoral and common femoral veins. Regarding laboratory data for the coagulation system, there were no cases with D-dimer above 5 µg/ml. Concerning sudden death in patients with SMID, we have to be very careful of the possibility of pulmonary thromboembolism due to DVT. Therefore, we should consider the particularities of an underdeveloped vascular system from underlying diseases for the evaluation of DVT in patients with SMID. A detailed study of DVT as a vascular complication is very important for smooth medical care of SMID and compression Doppler ultrasonography of the lower extremities, as noninvasive examination, is very helpful. (English translation of Jpn J Phlebol 2012; 23: 17-24).