Exploration of the Cytoplasmic Function of Abnormally Fertilized Embryos via Novel Pronuclear-Stage Cytoplasmic Transfer

In regular IVF, a portion of oocytes exhibit abnormal numbers of pronuclei (PN) that is considered as abnormal fertilization, and they are routinely discarded. However, it is known that abnormal ploidy still does not completely abandon embryo development and implantation. To explore the potential of cytoplasm from those abnormally fertilized oocytes, we developed a novel technique for the transfer of large cytoplasm between pronuclear-stage mouse embryos, and assessed its impact. A large volume of cytoplast could be efficiently transferred in the PN stage using a novel two-step method of pronuclear-stage cytoplasmic transfer (PNCT). PNCT revealed the difference in the cytoplasmic function among abnormally fertilized embryos where the cytoplasm of 3PN was developmentally more competent than 1PN, and the supplementing of fresh 3PN cytoplasm restored the impaired developmental potential of postovulatory “aged” oocytes. PNCT-derived embryos harbored significantly higher mitochondrial DNA copies, ATP content, oxygen consumption rate, and total cells. The difference in cytoplasmic function between 3PN and 1PN mouse oocytes probably attributed to the proper activation via sperm and may impact subsequent epigenetic events. These results imply that PNCT may serve as a potential alternative treatment to whole egg donation for patients with age-related recurrent IVF failure.     

Superoxide dismutases exhibit oxidase activity on aldehyde alcohols similar to alcohol oxidase from Paenibacillus sp. AIU 311

The relations between oxidase activity on aldehyde alcohols and superoxide dismutase (SOD) were investigated, since the amino terminal amino acid sequence of alcohol oxidase (AOD) from Paenibacillus sp. AIU 311, which was specific to aldehyde alcohols, exhibited high similarity to those of SODs containing manganese (Mn(2+)-SOD). Paenibacillus AOD had high SOD activity. The SODs containing manganese, iron, or copper and zinc also exhibited oxidase activities on aldehyde alcohols, and the relative values of oxidase activities on aldehyde alcohols to SOD activity of Mn(2+)-SOD were closer to those of Paenibacillus AOD compared with those of the other SODs. Thus, SODs had AOD activity on aldehyde alcohols as another enzyme activity, and the Paenibacillus AOD and Mn(2+)-SOD were classified into a similar group.     

Reduced platelet adhesion and blood coagulation on cross-linked albumin films

Surface-induced thrombosis is a major complication associated with blood-contacting biomaterials. Cross-linked albumin films possessing native albumin characteristics such as resistance to cell adhesion and drug binding ability are available for improving the blood compatibility of biomaterial surfaces. In the present study, we aimed to evaluate the blood compatibility of cross-linked albumin films. Platelet adhesion analysis showed that albumin film coated substrates exhibited very low platelet adhesion, and platelet adhesion was further suppressed by loading the antiplatelet drug, cilostazol, into the film. Monitoring the coagulation process of whole blood using a coaxial-cylinder rotational viscometer showed that the initial time of coagulation in albumin film coated cylinders was delayed compared with that in uncoated cylinders, suggesting that activation of the intrinsic coagulation cascade was reduced on the albumin film coated surface. Thus, surface coating with cross-linked albumin films is a promising approach to conferring biomaterials with antithrombogenic surfaces due to the resistance to platelet adhesion and the antiplatelet drug-releasing capability afforded by the films.     

Foods with complaints of fungal contamination and physical problems caused by their ingestion

A survey concerning foods for which complaints of fungal contamination had been made was carried out by distributing and retrieving a questionnaire. The subject of the survey was foods that were examined for fungi by institutes and laboratories belonging to regulatory agencies following consumers' complaints or upon request from food companies to solve problems. We analyzed 1,096 cases recovered from 40 organizations located in 30 prefectures. Most foods with fungal contamination were "cake and snacks", "beverages" and "bakery products", and processed and cooked foods and beverages accounted for more than 90% of the complaints. The numbers of cases were greater in the summer and less in the winter. The major fungal genus detected in the suspect foods were Penicillium, Aspergillus and Cladosporium. Aspergillus niger was the dominant species contaminating bakery products. Complainers reported physical symptoms including diarrhea, stomach ache, nausea and vomiting in 18% of the cases in which they had eaten or drunk fungus-contaminated foods or beverages. There was no clear difference in the fungi detected between foods and beverages that caused symptoms and those that did not. The proportion of beverages was greater in the foods that induced symptoms than in the whole of the foods for which complaints were made. This was presumed to be because consumers drank fungus-contaminated beverages more often than they ate fungus-contaminated foods.     

Biomimetic coating of an apatite layer on poly(<Emphasis Type="SmallCaps">l</Emphasis>-lactic acid); improvement of adhesive strength of the coating

A biodegradable polymer coated with a bonelike apatite layer on its surface would be useful as a scaffold for bone tissue regeneration. In this study, poly(l-lactic acid) (PLLA) was treated with oxygen plasma to produce oxygen-containing functional groups on its surface. The plasma-treated specimen was then alternately dipped in aqueous CaCl₂ and K₂HPO₄·3H₂O solutions three times, to deposit apatite precursors onto the surface. The surface-modified specimen then successfully formed a dense and uniform bonelike surface apatite layer after immersion for 24 h in a simulated body fluid with ion concentrations approximately equal to those of human blood plasma. The adhesive strength between the apatite layer and the specimen surface increased as the power density of the oxygen plasma used increased. The maximum adhesive strength of the apatite layer to the specimen was significantly higher than that to the commercially available artificial bone, HAPEX^TM. The resultant bonelike apatite–PLLA composite would be useful as a scaffold for bone tissue regeneration.     

Calcium phosphate coating formed in infusion fluid mixture to enhance fixation strength of titanium screws

A novel technique was developed to coat a calcium phosphate (CaP) layer on titanium screws with a titanium oxide surface layer, using infusion fluids officially approved for clinical use. A calcium-containing solution, a phosphate-containing solution, and a sodium bicarbonate solution prepared from the infusion fluids were mixed at a Ca/P molar ratio of 2.0. Each screw was immersed in 10 mL of the resulting mixture at 37 °C for 2 days. A low-crystalline apatite layer (Ca/P molar ratio = 1.681 ± 0.038) was formed on the screws. The layer consisted of a few 100 nm diameter particles fixed on the screw surface. In animal experiments, the screws were percutaneously implanted in both proximal tibial metaphyses of rabbits. The insertion torque was not significantly different between the CaP-coated screws (0.132 ± 0.002 Nm, n = 10) and uncoated screws (0.140 ± 0.002 Nm, n = 10) (p = 0.5785). After the insertion torque test, the apatite layer remained on the surface of the screws, which means that the apatite layer survived the friction of screw insertion. The extraction torque of the screws in the CaP-coated group (0.239 ± 0.066 Nm, n = 19) was significantly higher (by 29.9%) than that in the uncoated group (0.184 ± 0.062 Nm, n = 18) 4 weeks after the operations (p = 0.0132). Histologically, a larger amount of new bone formation was observed around the CaP-coated screws than that around the uncoated screws. Even after the removal of the screw, the CaP layer remained on the screw at the site where soft tissues were attached. The coating technique with the use of the infusion fluids is an effective method of improving bone-screw interface strength.     

Polyion complex fiber and capsule formed by self‐assembly of poly‐L‐Lysine and gellan at solution interfaces

Different characteristic surface structures such as capsules, regularly spaced droplets, and fibers are formed by electrostatic interaction between poly‐L ‐lysine (PLL) and gellan gum via polyion complex (PIC) formation. Spherical droplet PIC capsules of varying diameters form in solutions. Some dyes adsorb on the surface of the capsules, and other dyes penetrate into the capsules. The strong PIC fiber can be spinnable by gravity and by wet spinning in ethanol. This fiber possesses a counterion pairing structure and exhibits the nervation/veining pattern and hollow yarn. The tensile strength of the fiber is 27.8 kg/mm² [1.40 g/denier (d)] and the knotting strength is 9.98 kg/mm² (1.13 g/d). By using an organic crosslinking agent, epichlorohydrin, the tensile strength can be increased to 38.5 kg/mm² (2.46 g/d) and the knotting strength can be increased to 12.2 kg/mm² (1.99 g/d). The PIC fiber can be dyed by five different dyeing procedures such as direct and vat dyeings. The PLL PIC fiber is water insoluble and has potential as a new synthetic polypeptide fiber technology. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 437–446, 2001     

Effect of ultraviolet radiation on photodegradation of collagen

Photodegradation of solvent-cast collagen type I films and photostabilization of collagen by vitamin E were studied. These films were exposed to polychromatic radiation from a medium-pressure mercury lamp or monochromatic radiation from the Okazaki Large Spectrograph (OLS). Changes in the molecular structure of collagen were followed by UV-visible and FTIR spectroscopic measurements. Electron spin resonance (ESR) spectroscopic measurements were also carried out to identify the reaction intermediates of photodegradation. Photoreaction from phenylalanine, which is one of the main constituents of collagen to tyrosine and the scission of peptide linkage of collagen, were confirmed. Vitamin E was found to be an efficient photostabilizer for photodegradation of collagen. Action spectra of photodegradation and photostabilization of a collagen molecule were reported. A possible mechanism for the photodegradation of the collagen and photostabilization scheme based on these experimental results are presented. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 1259–1265, 1999