Hierarchical viscosity of aqueous solution of tilapia scale collagen investigated via dielectric spectroscopy between 500 MHz and 2.5 THz

Aqueous solutions of biomolecules such as proteins are very important model systems for understanding the functions of biomolecules in actual life processes because interactions between biomolecules and the surrounding water molecules are considered to be important determinants of biomolecules’ functions. Globule proteins have been extensively studied via dielectric spectroscopy; the results indicate three relaxation processes originating from fluctuations in the protein molecule, the bound water and the bulk water. However, the characteristics of aqueous solutions of collagens have rarely been investigated. In this work, based on broadband dielectric measurements between 500 MHz and 2.5 THz, we demonstrate that the high viscosity of a collagen aqueous solution is due to the network structure being constructed of rod-like collagen molecules surrounding free water molecules and that the water molecules are not responsible for the viscosity. We determine that the macroscopic viscosity is related to the mean lifetime of the collagen-collagen interactions supporting the networks and that the local viscosity of the water surrounded by the networks is governed by the viscosity of free water as in the bulk. This hierarchical structure in the dynamics of the aqueous solution of biomolecules has been revealed for the first time.

Virulence of acute hepatopancreatic necrosis disease PirAB-like relies on secreted proteins not on gene copy number

AIMS

To investigate the virulence of the Vp_PirAB-like genes in Vibrio parahaemolyticus- acute hepatopancreatic necrosis disease (AHPND)-causing strain and the factors that are associated with the virulence level.

METHODS AND RESULTS

The virulence of Vp_PirAB-like was examined using a non-virulent strain FP11 of V. parahaemolyticus transformed with a plasmid harbouring Vp_PirAB-like genes and then it was used to challenge shrimp Litopenaeus vannamei and Marsupenaeus japonicus. Both species experienced 100% mortality at 10 days post infection. Analysis of a mutant strain (E1M), that was originally identified as virulent strain (E1) but lost its virulence to L. vannamei, revealed that it lacked a part of the Vp_PirA-like gene and all of the Vp_PirB-like gene. The copy numbers of Vp_PirA-like and Vp_PirB-like genes varied among virulent strains and were not correlated with their virulence. In Western blotting, Vp_PirA-like and Vp_PirB-like proteins were detected in both the cell lysate and the culture supernatant. The strongest intensity of detecting band in the culture supernatant was observed in the strain that caused the highest mortality. The V. parahaemolyticus AHPND-causing strain, unlike the human tdh-positive strain, did not show any enterotoxicity.

CONCLUSION

Vibrio parahaemolyticus AHPND-causing strains secrete the Vp_PirA-like and Vp_PirB-like proteins during the growing phase. The amount of secreted proteins affects the shrimp mortality.

SIGNIFICANCE AND IMPACT OF THE STUDY

The secreted proteins of Vp_PirAB-like are key factors of virulence in the V. parahaemolyticus AHPND-causing strain, but not gene copy.

Refinement of nano-structured fibroin thin films by near-IR pulsed laser deposition from targets consolidated with autogenous binder

Silk fibroin (SF) powders were mixed with an autogenous binder from a natural cocoon after degumming with Na(2)CO(3) and liquefied with LiBr. An all-fibroin ablation target, SLT, obtained from the mixture after compression at ambient temperature, was compared with those without autogenous binder, SWT, or with a simple, non-autogenous binder, hydroxypropyl methylcellulose, SHT. The targets were then irradiated by a 1064 nm laser beam to obtain nano-structured thin films of fibroin by pulsed laser deposition (PLD) on Si (100). The properties of PLD films were examined mainly by atomic force microscope (AFM) or scanning electron microscope (SEM) for microstructures and morphology. By using an autogenous binder, significant increase was observed in the rate of nanofilm deposition with simultaneous decrease in the fraction of large debris. Size reduction of smallest protein units (SPUs) was also recognized by AFM. The autogenous binder turned out to be significantly superior over conventional, non-autogenous ones.

[Surgical experience of idiopathic peripheral pulmonary arterial aneurysm; report of a case]

Peripheral pulmonary arterial aneurysm has rarely been reported, and although most cases show symptoms of hemoptysis. We experienced a case of idiopathic peripheral pulmonary arterial aneurysm in the asymptomatic period noted on medical examination. The patient was a 49-year-old man with coin lesion which was 15 mm in diameter in the right lower lung field on chest X-ray film at the 1st visit. It was strongly stained on enhanced computed tomography in the right S4 and continuity with the pulmonary arteries was suggested. The right middle lobectomy was performed under the diagnosis of peripheral pulmonary arterial aneurysm. Histological examination of the resected specimen revealed that the prominent thinning in the arterial wall, however, there was no evidence of specific chronic inflammation. The postoperative course was good. The patient has been well without new pulmonary arterial aneurysm for 2 years after the surgery.

Effects of water on the primary and secondary relaxation of xylitol and sorbitol: implication on the origin of the Johari-Goldstein relaxation

Dielectric spectroscopy was employed to study the effects of water on the primary alpha -relaxation and the secondary beta -relaxation of xylitol. The measurements were made on anhydrous xylitol and mixtures of xylitol with water with three different water concentrations over a temperature range from 173 K to 293 K. The alpha -relaxation speeds up with increasing concentration of water in xylitol, whereas the rate of the beta -relaxation is essentially unchanged. Some systematic differences in the behavior of alpha -relaxation for anhydrous xylitol and the mixtures were observed. Our findings confirm all the observations of Nozaki et al. [J. Non-Cryst. Solids 307, 349 (2002)]] in sorbitol/water mixtures. Effects of water on both the alpha - and beta -relaxation dynamics in xylitol and sorbitol are explained by using the coupling model.

Endogenous TNF inducibility and prognosis of colorectal cancer

BACKGROUND

We have demonstrated that the inducibility of endogenous TNF (en-TNF) by colorectal tumor cells is a factor in predicting a patient prognosis. The prognoses of colorectal tumor patients with the K-ras gene mutations in their tumors were poorer to those of patients with the wild type gene. Therefore, we analyzed the possible relationship between the inducibility of en-TNF by colorectal tumor cells during the follow-up of patients with K-ras mutations.

MATERIALS AND PATIENTS

In 62 of 154 Dukes Stage C patients who received curative operation from June 1988 to June 1997, the prognoses in terms of the tumor-free rate and survival rate were compared with the inducibility of en-TNF by colorectal tumor cells, which were classified into three groups: grade 1: > or = 500 pg/ml, grade 2: 100-500 pg/ml, and grade 3: < 100 pg/ml. Regardless of the Dukes Stage of the patients, the K-ras gene was analyzed in 21 whose colorectal tumor cells were classified as grade 1: 8, grade 2: 4, and grade 3: 9.

RESULTS

The tumor-free rate of the patients with grade 1 was significantly higher than that of the patients with grade 3, and the survival period of the patients with grades 1 and 2 was significantly longer than that of the patients with grade 3. Possible mutations disorder of K-ras were observed in 37.5% (grade 1), 50.0% (grade 2), and 88.9% (grade 3) of cases, respectively.

CONCLUSION

The prognostic value of the inducibility of en-TNF by colorectal tumor cells from colorectal cancer patients who received curative operation at Dukes Stage C was confirmed. It is suggested that K-ras mutation may affect patient prognosis through modulation of the quality and/or quantity of cytokines such as TNF produced by tumor cells.

Clinical investigation of colorectal cancer detected by follow-up colonoscopy after endoscopic polypectomy

PURPOSE

We analyzed the results of a long-term follow-up surveillance of patients with colorectal polyps after endoscopic polypectomy in terms of the cumulative incidence of subsequent colorectal cancer and the clinicopathologic characteristics of carcinomas detected by colonoscopy.

METHOD

The study cohort consisted of 6,715 patients who had received endoscopic resection of single or multiple colorectal polyps and then underwent periodic colonoscopy (or a combination of sigmoidoscopy and barium x-ray examination in some cases) during an average follow-up of six years (40,622 person-years in total).

RESULTS

During the follow-up, 31 cases of colorectal cancer containing 15 submucosal invasive carcinomas (T1,N0,M0) and 16 advanced carcinomas were detected. The cumulative incidence of colorectal cancer was analyzed for four subgroups of the 6,715 patients classified according to the diameter, grade of dysplasia, and histologic features of polyps. Furthermore, the depth of invasion, macroscopic configuration of submucosal invasive cancer, and site of colorectal cancer observed in the 31 cases were compared with those of a reference group of 1,497 patients with colorectal cancer treated at Takano Hospital during the same period. Submucosal invasive cancer was the most common type among the colorectal carcinomas detected during follow-up. In terms of macroscopic configuration of submucosal cancer, the superficial type was significantly more common than the protruded type. The superficial submucosal cancer showed a significantly longer interval to detection than the protruded submucosal cancer. By site of lesion, proximal colon cancer was significantly more common.

CONCLUSION

Follow-up colonoscopy appears to be useful in patients with larger polyps (>5 mm). Patients with severe dysplasia and those with malignant polyps should be followed-up carefully. Because submucosal cancer detected by follow-up examination after polypectomy showed higher rates of superficial-type cancer and proximal colon cancer, careful endoscopic examination of the entire colon is important.

Temperature dependence of crystal structure of NaK0.72(NH4)0.28(+)-C4H4O6.4H2O in the paraelectric phase

The crystal structures of the ferroelectric NaK0.72 (NH4)0.28(+)-C4H4O6.4H2O (RS0.72ARS0.28) have been studied in the paraelectric phase [Mr = 276.32, orthorhombic, P21212,° Z = 4, F(000) = 575.04, λ(Mo Kα1) = 0.70926 Å]; T = 213 (1), 253 (1) and 293 (1) K. The crystal data are as follows: (I) at T = 213 (1) K: R = 0.0424, wR = 0.0399, number of reflections = 3414, a = 11.899 (2), b = 14.273 (2), c = 6.211 (1) Å, V = 1054.9 (2) Å3, Dx = 1.740 g cm−3; (II) at T = 253 (1) K: R = 0.0498, wR = 0.0442, number of reflections = 3284, a = 11.929 (1), b = 14.297 (1), c = 6.221 (1) Å, V = 1061.0 (2) Å3, Dx = 1.730 g cm−3; (III) at T = 293 (1) K: R = 0.0473, wR = 0.0392, number of reflections = 3179, a = 11.955 (1), b = 14.317 (1), c = 6.231 (1) Å, V = 1066.5 (1) Å3, Dx = 1.721 g cm−3. X-ray investigations reveal details of structural change with temperature in the paraelectric phase. The carboxylate anion O(3)—C(4)—O(4) in the tartrate molecule is displaced along the a axis as the temperature decreases; moreover, the O(8) atom is displaced in the opposite direction against the shift of the carboxylate anion. The temperature dependence of the thermal motions of O(8) shows different behavior from the other O atoms of the water molecules. The amplitude of the thermal motion of O(8) does not tend to zero at T = 0 K, while the other O atoms of the water molecules tend to zero.

Modification of crystal structure of ammonium Rochelle salt [NaNH4(+)-C4H4O6.4H2O] owing to the replacement of NH4 ions with K ions

The crystal structures of NaK1−x (NH4) x (+)-C4H4O6.4H2O (RS1−x ARS x , x = 0.90, 0.94 and 1.00) have been determined in the paraelectric phase (T = 294 K). The crystal data are: for ARS, orthorhombic, P21212, R = 0.038, wR = 0.032, no. of reflections = 3373, a = 12.206 (7), b = 14.451 (6), c = 6.250 (4) Å, V = 1102 (1) Å3, Z = 4, Dx = 1.573 g cm−3, λ(MoKα) = 0.70926 Å, F(000) = 552.00; for RS0.06ARS0.94, orthorhombic, P21212, R = 0.040, wR = 0.030, no. of reflections = 2446, a = 12.172 (4), b = 14.421 (4), c = 6.239 (2) Å, V = 1095.2 (6) Å3, Z = 4, Dx = 1.592 g cm−3, λ(Mo Kα1) = 0.70926 Å, F(000) = 553.92; for RS0.10ARS0.90, orthorhombic, P21212, R = 0.036, wR = 0.027, no. of reflections = 1898, a = 12.165 (9), b = 14.420 (7), c = 6.239 (4) Å, V = 1094 (1) Z = 4, Dx = 1.598 g cm−3, λ(Mo Kα1) = 0.70926 Å, F(000) = 555.20. In the crystals there are two crystallographically nonequivalent cation sites occupied by K/NH4 ions. The accommodation ratios of sites (1) [(2a) by the Wyckoff notation] and (2) [(2b)] are 0.94 (1) and 0.92 (1), respectively, in RS0.06ARS0.94, and 0.90 (1) and 0.93 (1), respectively, in RS0.10ARS0.90. As x increases, the location of site (2) displaces towards the origin. The hydrogen bonds around sites (1) and (2) are classified into two types: one is that the distances become longer as x increases, due to the difference in the ionic radii of K and NH4 ions, while the other is that the distances are equal. Comparing the crystal structure of ARS to that of RS, the following differences occur: the position of site (2), the interatomic distances between cations of sites (1) and (2) and O atoms, the form of the tartrate molecule and the position of some water molecules. These differences seem to be mainly caused by the replacement of NH4 ions by K.

Management of early invasive colorectal cancer. Risk of recurrence and clinical guidelines

PURPOSE

The purpose of this study was the evaluation of various factors in the formulation of guidelines for treatment of early invasive colorectal cancer, in which malignant cells extend through the muscularis mucosa into the submucosa but do not deeply invade the muscularis propria.

METHOD

A total of 182 patients were followed for at least five years or until death, with early invasive cancer diagnosed between 1982 and 1989. Patients were grouped according to the level of invasion, as follows: 64 patients with slight carcinoma invasion of the muscularis mucosa (200-300 microns; sm1), 82 with intermediate invasion (sm2), and 36 with carcinoma invasion extending to the inner surface of the muscularis propria (sm3).

RESULT

The configuration, diameter, and histologic grade of adenocarcinoma and lymphovascular invasion were correlated with level of invasion. After endoscopic polypectomy or local resection, 4 patients showed local recurrence and 13 patients showed lymph node metastasis. None of these 17 patients had sm1 disease. The level of invasion, configuration, and location were significant risk factors for development of lymph node metastasis or local recurrence (P < 0.05), but lymphovascular invasion, histologic grade, and diameter were not risk factors.

CONCLUSIONS

Preoperative assessment of the level of invasion using this classification, in which the submucosa is divided into three depths, may decrease the incidence of unnecessary surgery for sessile polyps. Assessment according to the level of invasion is useful in the formulation of appropriate guidelines for the treatment of early invasive cancer.