Synthesis of 6-Methyluridine via Palladium-Catalyzed Cross-Coupling Between A 6-Iodouridine Derivative and Tetramethylstannane

Abstract

6-Methyluridine can be synthesized from 5′-O-(tert-butyl-dimethylsilyl)-6-iodo-2′,3′-O-isopropylideneuridine via palladiumcatalyzed cross-coupling with Me₄Sn followed by deprotection. Application of this method for the synthesis of 6-phenyluridine was also carried out.     

Onset of Buccal Pumping in Catshark Embryos: How Breathing Develops in the Egg Capsule

Respiration in fishes involves buccal pumping, which is characterized by the generation of nearly continuous water flow over the gills because of the rhythmic expansion/compression of the pharyngeal cavity. This mechanism is achieved by the functions of the vascular, skeletal, and muscular systems. However, the process by which the embryo establishes the mechanism remains a mystery. Morphological and kinematical observations on captive cloudy catsharks, Scyliorhinus torazame, have suggested that the embryo starts buccal pumping just before the respiratory slits open on the egg capsule. During the pre-opening period, the embryo acquires oxygen mainly via the external gill filaments. After slit opening, respiration of the embryo involves buccal pumping to pass water over the “internal gills.” The onset of buccal pumping accompanies four morphological changes: (1) regression of the external gill filaments, (2) development of blood vessels within the “internal gills,” (3) completion of the development of hyoid skeletal and muscular elements, and (4) development of the oral valve. A previous study showed that buccal pumping allows the embryo to actively regulate oxygen intake by changing the pumping frequency. Thus, establishment of buccal pumping in the egg capsule is probably important for embryo survival in the unstable oxygen environment of the egg capsule after slit opening.     

Phosphate–Induced Renal Fibrosis Requires the Prolyl Isomerase Pin1

Tubulo-interstitial fibrosis is a common, destructive endpoint for a variety of kidney diseases. Fibrosis is well correlated with the loss of kidney function in both humans and rodents. The identification of modulators of fibrosis could provide novel therapeutic approaches to reducing disease progression or severity. Here, we show that the peptidyl-prolyl isomerase Pin1 is an important molecular contributor that facilitates renal fibrosis in a well-characterized animal model. While wild-type mice fed a high phosphate diet (HPD) for 8–12 weeks developed calcium deposition, macrophage infiltration and extracellular matrix (ECM) accumulation in the kidney interstitium, Pin1 null mice showed significantly less pathology. The serum Pi in both WT and KO mice were significantly increased by the HPD, but the serum Ca was slightly decreased in KO compared to WT. In addition, both WT and KO HPD mice had less weight gain but exhibited normal organ mass (kidney, lung, spleen, liver and heart). Unexpectedly, renal function was not initially impaired in either genotype irrespective of the HPD. Our results suggest that diet containing high Pi induces rapid renal fibrosis before a significant impact on renal function and that Pin1 plays an important role in the fibrotic process.     

Effect of Hypochlorite-Based Disinfectants on Inactivation of Murine Norovirus and Attempt to Eliminate or Prevent Infection in Mice by Additionto Drinking Water

We evaluated the in vitro efficacy of weak acid hypochlorous solution (WAHS) against murine norovirus (MNV) by plaque assay and compared the efficacy with diluted NaOCl (Purelox) and 70% ethanol. WAHS was as effective as 70% ethanol and diluted Purelox for 0.5-min reactions. For 0.5-min reactions in the presence of mouse feces emulsion, the efficacy of WHAS and 1:600 diluted Purelox was decreased, reducing the virus titers by 2.3 and 2.6 log₁₀, respectively, while 70% ethanol reduced the titer by more than 5 log₁₀. However, WAHS showed more than 5 log₁₀ reductions for the 5-min reaction even in the presence of feces emulsion. Since WAHS showed enough efficacy in inactivating MNV in vitro, we tried to eliminate MNV from MNV-infected mice by substituting WAHS for their drinking water. However, MNV was found to be positive in feces of mice drinking WAHS by an RT-nested PCR and plaque assay. To investigate whether hypochlorite-based disinfectants could prevent infection of a mouse with MNV, WAHS or 1:6,000 diluted Purelox was substituted for the drinking water of mice for 2 or 4 weeks, and then the mice were placed in a cage with an MNV-infected mouse. The supply of disinfectants was continued after cohabitation, but MNV was detected in the feces of all the mice at 1 week after cohabitation. In this study, we tried to eliminate and prevent MNV infection from mice by supplying hypochlorite-based disinfectants as an easy and low-cost method. Unfortunately, drinking disinfectants was ineffective, so it is important to keep the facility environment clean by use of effective disinfectants. Also, animals introduced into facilities should be tested as MNV free by quarantine and periodically confirmed as MNV free by microbiological monitoring.     

Synthesis and Biological Evaluation of 1′-C-Cyano-Pyrimidine Nucleosides

Abstract

2′-Deoxy-, 2′-bromo-, and arabino-1′-C-cyano-pyrimidine nucleosides were synthesized from O² ,2′-cyclouridine. Incorporation of cyano group at the anomeric position was achieved by treatment of 1′,2′-unsaturated uridine with NBS in the presence of pivalic acid followed by TMS-cyanide and stannic chloride. Antineoplastic and antiviral activities of those compounds are also discussed.

     

Effects of Coexistence of β-Casein on Gelation of κ-Carrageenan

The effects of caseins on the rheological properties of κ-carrageenan-calcium gel was investigated by measuring the gel breaking strength. The existence of β-casein in the system promoted the gelation of κ-carrageenan in the presence of calcium ion. Beta-casein increased the strength of calcium gels of κ-carrageenan with increasing NaCl concentration up to 80 mM and strengthened the κ-carrageenan-calcium gel at neutral pH. The values obtained from the slopes of the logarithmic plots of the gel strength versus concentration were 2.15 for κ-carrageenan gel and 2.27 for a β-casein-κcarrageenan mixture gel, suggesting that β-casein may participate in the gelation of κ-carrageenan through the mediation of calcium ions.     

Molecular Characterization of Low-Molecular-Weight Component Protein,Flp, in Actinobacillus actinomycetemcomitans Fimbriae

Fimbriae preparation from Actinobacillus actinomycetemcomitans was found to contain an abundant low-molecular-weight protein (termed Flp) with an apparent molecular mass of approximately 6.5 kDa, in addition to a small amount of 54-kDa protein. Immunogold electron microscopy localized the Flp protein at the bacterial fimbriae but not at the cell surface. The DNA fragment including the flp gene was cloned from A. actinomycetemcomitans 304-a and its nucleotide sequence was determined. An open reading frame of the flp gene was composed of 225 bp encoding a protein of 75 amino acids. Comparison of the translated amino acid sequence with the sequence of native Flp determined by Edman degradation indicated that the N-terminal part of 26 amino acids is leader peptide. The N-terminal sequence of mature Flp exhibited some similarity to type-IV pilin. Furthermore, the processing site of premature Flp is also similar to that of type-IV prepilin, and a gene encoding a protein homologous to type-IV prepilin-like protein leader peptidase was found downstream of the flp gene. These findings indicate that Flp is the major component protein of A. actinomycetemcomitans fimbriae.     

Role of Diffusion Weighted Imaging and Contrast-Enhanced MRI in the Evaluation of Intrapelvic Recurrence of Gynecological Malignant Tumor

Background and Purpose

To investigate the diagnostic performance of diffusion-weighted imaging (DWI) and contrast-enhanced imaging in combination with T2-weighted imaging (T2WI) for magnetic resonance imaging (MRI) evaluation of intrapelvic recurrence of gynecological malignancies.

Materials and Methods

Sixty-two patients with suspected intrapelvic recurrence of gynecological malignancies underwent pelvic MRI including T2WI DWI, and contrast-enhanced imaging. Diagnostic performance for detection of local recurrence, pelvic lymph node and bone metastases, and peritoneal lesions was evaluated by consensus reading of two experienced radiologists using a 5-point scoring system, and compared among T2WI with unenhanced T1-weighted imaging (T1WI) (protocol A), a combination of protocol A and DWI (protocol B), and a combination of protocol B and contrast-enhanced imaging (protocol C). Final diagnoses were obtained by histopathological examinations, radiological imaging and clinical follow-up for at least 6 months. Receiver operating characteristic (ROC) analysis and McNemar test were employed for statistical analysis.

Results

Locally recurrent disease, lymph node recurrence, peritoneal dissemination and bone metastases were present in 48.4%, 29.0%, 16.1%, and 6.5% of the patients, respectively. The patient-based sensitivity, specificity, accuracy, and area under the ROC curve (AUC) for detection of intrapelvic recurrence were 55.0, 81.8, 64.5% and 0.753 for protocol A, 80.0, 77.3, 79.0% and 0.838 for protocol B, and 80.0, 90.9, 83.9% and 0.862 for protocol C, respectively. The sensitivity, accuracy, and AUC were significantly better for protocols B and C than for protocol A (p<0.001). There was no significant difference between protocols B and C.

Conclusion

MRI using a combination of DWI and T2WI gives comparatively acceptable results for assessment of intrapelvic recurrence of gynecological malignancies.