Simple method for determining proper length of artificial chordae in mitral valve repair.

A simple method for determining the length of artificial chordae in mitral reconstructive operations is described. A small tourniquet is used for fine adjustment of the length of polytetrafluoroethylene stitches before tying them during leaking test. We have used this technique in 10 consecutive patients with anterior mitral leaflet prolapse since August 1992. Intraoperative transesophageal echocardiography revealed no or only trace mitral regurgitation after valve repair in all cases. This method minimized the time of determining the proper length of artificial chordae and achieved good results.

Astroglial cells inhibit the increasing permeability of brain endothelial cell monolayer following hypoxia/reoxygenation.

Blood-brain barrier (BBB) is known to be structured with astroglial cells (AGs) and brain endothelial cells (BECs), and it has been proposed that these cells play different roles in the BBB. We cultivated AGs and BECs from infant rats (2-week-old), and these cells were cultured on the opposing side of collagen membrane to produce a co-culture model of the BBB in vitro. Permeability of the cell layer was evaluated by the electrical resistance through the membrane. To clarify the role of AGs in the BBB disruption following ischemia/reperfusion, electrical resistance of the co-culture model was compared to that of BEC monolayer following hypoxia/reoxygenation. The electrical resistance through BEC monolayer showed 55.5 +/- 15.1 percent reduction at 4 h of hypoxia, and 93.3 +/- 5.4 percent reduction at 8 h of hypoxia (n = 8). However, the co-culture model showed attenuation of the reduction (24.8 +/- 14.2 percent) at 4 h of hypoxia (n = 8, P < 0.01), but not at 8 h of hypoxia (95.3 +/- 5.0 percent). These results indicate that AGs reduce the increasing permeability of the BEC monolayer following short duration of hypoxia/reoxygenation. It is suggested that AGs may have a protective effect to the BBB disruption following ischemia/reperfusion.

Selective cytotoxic activity of grape peel and seed extracts against oral tumor cell lines.

Grape seed extracts were more cytotoxic than grape peel extracts. Methanol and 70% methanol extracts of grape seed selectively killed two human oral tumor cell lines, more efficiently than human gingival fibroblasts. ESR spectroscopy revealed that these extracts produced radicals under alkaline conditions and enhanced the radical intensity of sodium ascorbate at higher concentrations. On the other hand, lower concentration of these extracts slightly reduced the radical intensity of sodium ascorbate, and scavenged superoxide anion, generated by hypoxanthine and xanthine oxidase reaction. These properties of grape seed extracts suggest their possible application for cancer prevention.

Severe hemolysis due to artificial chordae displacement.

Hemolytic anemia is a well-recognized complication of mechanical heart valve prosthesis but, as yet, has not been reported after mitral valve repair with chordal replacement. We report a case of severe hemolytic anemia after mitral valve repair with chordal replacement and Carpentier-Edwards annuloplasty ring insertion. Progressive prolapse of the anterior leaflet due to the artificial chordae being too long caused recurrent regurgitation which was responsible for the hemolysis. The patient also had idiopathic thrombocytopenic purpura, but successful second mitral valve repair was performed after high-dose gamma-globulin therapy.

Biological activity of a fruit vegetable, "Anastasia green", a species of sweet pepper.

Russian green sweet pepper (Anastasia Green) was successively extracted with hexane, acetone, methanol and 70% methanol and the extracts were further separated into a total of twenty fractions by silica gel or ODS column chromatographies. The biological activities of these extracts and fractions were compared. The extracts and fractions showed higher cytotoxic activity against two human oral tumor cell lines than against normal human gingival fibroblasts, suggesting their tumor-specific action. Several fractions [H3, H4, A4] reversed the multidrug resistant gene (MDR1) against L5178 mouse T-cell lymphoma more effectively than (+/-) verapamil (positive control). All extracts and fractions showed no anti-human immunodeficiency virus (HIV) nor anti-Helicobacter pylori activity. These data suggest the medicinal importance of an Anastasia Green extract.

Research into changes in canine maxillary trabecular bone orientation after tooth extraction.

This paper described the morphological changes in the trabecular bone orientation of the jaw bone due to reduction in the applied functional pressure. All teeth on the right side of the upper and lower jaws were extracted from canine specimens. Experimental periods were set at 0.5, 1, 1.5, 2, 2.5, 3, 5, 7, 9, 11, and 13 months after tooth extraction. The trabecular bone orientation was measured by an image analyzer as morphometrical parameters. The loss of teeth changed the support system for functional pressure, resulting in the marked disordering of the trabecular bone orientation.

A study of the internal structure of the Japanese mandible.

The thickness of the substantia compacta and the volume and width of the trabecular bone of the substantia spongiosa were investigated by soft X-ray photographs made of thin sections of many kinds of dentulous and edentulous mandibles. The results were: 1) The thickness of substantia compacta is especially thick on the lingual side in the incisor region and thickest in the molar region in all materials. At the base of mandible, the thickness is essentially the same in all regions, but, the thickness of dentulous materials is greater than of edentulous ones. 2) On the upper part, the volume of trabecular bone is less in the premolar region in both edentulous and dentulous material than in other regions, however, there is relative more in edentulous than in dentulous. In the central part, there is almost the same amount of trabecular bone in the dentulous and edentulous material. 3) The width of the trabecular bone in the substantia spongiosa is greater in the incisor region than in other regions in all materials. In the upper and central part, it is smaller in the premolar region in both edentulous and dentulous material but, it increases in the molar region in the edentulous materials.

Quantitative and morphological studies on the trabecular bones in the condyloid processes of the Japanese mandibles. Comparisons between dentulous and edentulous specimens.

Using dentulous and edentulous specimens, mathematical morphology was applied to quantities bone morphology measurements, of the trabecular bones in the condyloid processes, which form the temporomandibular joint and are the center of mandibular motion. There is a tendency for trabecular bone density and width in edentulous specimens to be comparatively lower than for dentulous specimens and a similar decrease in continuity of the trabecular bones. Values for specific length are highest in dentulous specimens, indicating a greater degree of interlocking. A degree of regularity is observed in trabecular bone orientation; in edentulous specimens trabecular bones other than major ones are fewer and thinner.

Application of glutaraldehyde-crosslinked chitosan as a scaffold for hepatocyte attachment.

The effectiveness of chitosan, a biocompatible polymer derived by the deacetylation of chitin, as a scaffold of hepatocyte attachment, was examined. Since chitosan gel was too fragile to use for cell culture, its free amino groups were crosslinked by glutaraldehyde to increase its strength. Rat hepatocytes seeded onto glutaraldehyde-crosslinked chitosan (GA-chitosan) gel could stably attach to the surface, retaining its spherical form, the same as in vivo, and then release a very small amount of lactate dehydrogenase during the 5 d culture period. By contrast, hepatocytes on a collagen-coated surface spread flat, and they released much more lactate dehydrogenase than those on the GA-chitosan gel. Hepatocytes on GA-chitosan also retained higher urea synthesis activity, a liver-specific function, than those on the collagen-coated surface. These results indicate that chitosan is a promising biopolymer as a scaffold of hepatocyte attachment, which can be applied to an effective bioartificial liver support system.

Suppression of apoptosis in hepatocytes by fructose-modified dendrimers.

By immobilizing fructose-modified dendrimers on a polystyrene culture plate, the number of initially adhered hepatocytes on it was increased. Moreover, increasing the number of generations of fructose-modified dendrimer (fructose-dendrimer) increased the number. Urea synthesis per unit area also was increased, corresponding to the increase in the number of initially adhered hepatocytes. This result suggests that the fructose-dendrimers do not cause a decline in cell function. On the other hand, apoptosis of hepatocytes occurs during cultivation, and results in a decrease in the number of adhered cells and a decline in cell function. Fructose-dendrimers were found to suppress apoptosis of hepatocytes. This characteristic is considered to be responsible for the increase in the number of initially adhered hepatocytes without a decline in cell function. Fructose-dendrimers are shown to be very suitable scaffolds for use in a high-performance bioartificial liver support system.

Immobilization of tripeptide growth factor glycyl-L-histidyl-L-lysine on poly(vinylalcohol)-quarternized stilbazole (PVA-SbQ) and its use as a ligand for hepatocyte attachment.

A tripeptide growth factor, glycyl-L-histidyl-L-lysine (GHK), was immobilized on the surface of poly(vinylalcohol)-quarternized stilbazole (PVA-SbQ) gel. The photoreactive substance, 4-(3-trifluoromethylazirino)benzoyl-N-hydroxysuccinimide (TDBA-OSu), was employed to link the gel and ligand GHK. The density of immobilized GHK was 70 nmol/cm2. Isolated rat hepatocytes were inoculated on the GHK-immobilized PVA-SbQ gel and cultured for 5 d. About 24 h after inoculation, hepatocytes started to aggregate and formed multicellular spheroids while almost no cells attached to GHK-non-immobilized PVA-SbQ gel. The formed spheroids attached firmly to the surface of PVA-SbQ gel for 5 d. GHK was, thus, shown to be an effective ligand for hepatocyte attachment. Dodecamethylenediamine was used to extend the length between the gel surface and GHK. Extension of the length significantly increased the number of attached hepatocytes.

Study of the internal structure of the infantile zygomatic bone.

External measurements of the zygomatic bone have been reported, but there are no reports on the internal structure. We studied the internal structure of the zygomatic bone and determined the changes in cortical bone width, cortical bone ratio to total cross-sectional area, and trabecular bone width through six periods of tooth growth and development. Zygomatic bone were fixed in resin and sliced, then the cross-sectional specimens were photographed with soft X-rays. The images were analyzed with an image processor. The specimens included the surrounding cortical bone and its internal spongy substance. The cortical bone width, cortical bone ratio, and trabecular bone width increased significantly from the period of deciduous dentition to the first early period of mixed dentition, but leveled off after that. This indicates that in addition to the growth and development of the zygomatic bone itself, its structure is also affected by the forces generated in the maxilla by mastication.

Immobilization of ligand-modified polyamidoamine dendrimer for cultivation of hepatoma cells.

Cationic polyamidoamine dendrimers are known to be highly branched cascade polymers. The core part of these polymers, tris(2-aminoethyl)amine, was immobilized onto polystyrene plates to which animal cells do not adhere. using photoreactive 4-(3-trifluoromethylazirino) benzoyl-N-succinimide (TDBA-OSu). Cells of a rat hepatoma cell line, H4-II-E-C3, adhered to a surface immobilized with a first-generation dendrimer probably through interactions between the terminal amino groups of the dendrimer and the cell membranes. The adhered cells were viable, could proliferate, and exhibited urea synthetic activity. The modification of the terminal amino groups with fructose increased the final number of cells obtained after 5 days of cultivation. Multigeneration dendrimers were prepared by repeated linkage of tris(2-aminoethyl)amine with the amino groups. Theoretically, the number of terminal amino groups available for ligand modification is twice as much for each generation of dendrimer growth. Cells cultivated on multigeneration fructose-modified dendrimers exhibited enhanced urea synthetic activity. The use of ligand-modified dendrimers is, therefore, considered to be very promising for the construction of bioartificial organs based on cultivation of the animal cells.

Effectiveness of fructose-modified chitosan as a scaffold for hepatocyte attachment.

Free amino groups of chitosan, a substance which has previously been shown to be a good scaffold for hepatocyte attachment, were covalently modified with fructose. The modification significantly increased the number of cells that could be attached on the surface of chitosan gel. Rat hepatocytes cultivated on fructose-chitosan behaved similarly to those on unmodified chitosan, i.e., they retained the spherical shape they have in vivo, and released much less lactate dehydrogenase than cells attached on a collagen-coated surface. The modification with fructose did not alter the important characteristics of chitosan for hepatocyte culture: liver-specific functions such as urea synthesis and drug metabolism were stably maintained for 5 d in the hepatocytes cultured on fructose-chitosan. In sharp contrast, hepatocytes attached on a collagen-coated surface underwent a severe morphological change, from spherical to flat, and lost almost all their lidocaine-removal activity within 5d. A very thin fructose-chitosan layer was also applied onto the collagen-coated surfaces of polystyrene plates and a dextran microcarrier by crosslinking free amino groups in the chitosan and collagen with glutaraldehyde to fix the thin layer. Hepatocytes on the fructose-chitosan-coated surface retained their spherical shape, masking the cell-flattening effect of the collagen layer. Perfusion culture was then carried out using a hollow-fiber cartridge in which hepatocytes attached on fructose-chitosan-coated microcarriers were suspended in the extracapillary space: the liver-specific functions were stably maintained during 4d of the culture. A fructose-chitosan-coated surface thus appears to be a very promising scaffold for hepatocyte attachment which can be used in cellular biological studies of liver functions, especially in relation to cytochrome P450, as well as in bioartificial liver support systems.