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.

Physiologic remodeling annuloplasty to retain the shape of the anterior leaflet: a new concept in mitral valve repair

BACKGROUND AND AIMS OF THE STUDY

The Carpentier-Edwards (CE) ring was developed to restore the normal 3:4 ratio between the anteroposterior and transverse diameters of the mitral valve orifice during systole. It is difficult to use in patients in whom the ratio is more than 3:4. To overcome this problem, we developed an adjustable obturator, the ratio of which may be changed by sliding apart its two components.

METHODS

Remodeling annuloplasty was performed using part of a flexible Duran ring or autologous pericardium and the adjustable obturator in 17 patients with severe MR, including two with high anterior leaflet.

RESULTS

Physiologic remodeling annuloplasty was easily accomplished in all cases. Intraoperative echocardiography was performed in 14 patients, and it showed no regurgitant jet in 11 cases and only trivial jet in three.

CONCLUSION

Physiologic remodeling annuloplasty to retain the natural shape of the anterior leaflet by using an adjustable obturator is a very useful technique that enables annuloplasty to be performed in all cases, irrespective of the shape of the anterior leaflet.

[Radial artery for coronary artery bypass graft]

Early postoperative results were studied in 50 cases of coronary artery bypass graft (CABG) using a radial artery (RA). The patients ranged in age from 37 to 81 years, with the mean age of 61 years. Of them, 49 were male. An average of RA was 17.6 cm at completion of detachment and 15.6 cm when the graft was cut for use. The internal diameter before anastomosis an average of 3.7 mm on the proximal side and an average of 2.8 mm on the distal side. RA was anastomosed with ascending aorta in 47 cases, with the left internal thoracic artery in 2 cases and with the right internal thoracic artery in one case on the proximal side. RA was anastomosed with the left anterior descending branch area in 6 cases, with the left circumflex branch area in 40 cases and with the right coronary artery area in 4 cases on the distal side. There was no case of operative death, but one patient died while in hospital. The cumulative patency rate of the RA grafts was 95% (n = 40). Early postoperative results of the RA graft were satisfactory, therefore the RA graft were satisfactory, therefore the RA graft was an excellent alternative conduit for myocardial revascularization.

Drug resistance reversal, anti-mutagenicity and antiretroviral effect of phthalimido- and chloroethyl-phenothiazines

The effect of substituted phenothiazines was studied in three different systems; bacteria and cancer cells and reverse transcriptase enzyme of Moloney leukemia virus. F'lac and hemolysin plasmids were eliminated by some substituted phenothiazines from E. coli at a very low frequency. The same phenothiazine derivatives also were synergistic with tetracycline in bacteria and shown antimutagenic effect in Ames test. No mutagenic effects were observed in TA 98 strain of Salmonella typhimunium. Chloroethyl-substituted phenothiazines showed antimutagenicity equivalent to the parent compounds; however, phthalimido-substituted phenothiazines had higher antimutagenicity of 50%. P-glycoprotein responsible for multidrug resistance was also inhibited in tumor cells. The accumulation of the fluorescent rhodamine 123 in the phenothiazine treated multi-drug resistant tumor cells was measured by flow cytometry. Some of the substituted phenothiazines were effective P-glycoprotein blockers, while some compounds had moderate activity, but others were without effect as compared to 5 microM verapamil. On the basis of computer analysis there are some correlations between the biological activities and the dipole moments, and entropy of the studied molecules. Our results suggest that the inhibition of Hly+ plasmid replication and P-glycoprotein function may depend partly on similar electronic properties of the studied phenothiazine derivatives. The activity of Moloney leukemia virus reverse transcriptase was inhibited by the substituted phenothiazines, however, no basic differences were found in the activities of phthalimido- and chloroethyl substituted phenothiazines.

The primary in vitro antitumor screening of "half-mustard type" phenothiazines

The antitumor effects of "half-mustard type" phenothiazines were studied on 57 different tumor cell lines, including leukemias, non-small lung cancer, colon, central nervous system, ovarian, renal, breast, and prostate cancer, as well as melanoma cell cultures. Alkyl-urea derivatives of phenothiazines displayed in vitro antitumor activity. The phenothiazine phthalimido derivatives (1-6) were not active on the majority of cancer cell cultures. In contrast, propylureas (9, 11) were active against some leukemia cell types. Only two compounds with the butylene [(CH2)4] linker (10, 12) were active against non-small lung cancer cells. Compounds containing the propylene linker were less effective. On colon cancer lines, tumor cells from the central nervous system and on melanoma cells the same compounds were effective, however, having substituents at the 2-position of phenothiazine seems to be important. Surprisingly, the majority of ovarian cancer cell lines (except one type, IGROVI) and five of eight renal cancer lines were not sensitive to these phenothiazine derivatives. The two butylene linked phenothiazine ureas (10, 12) had moderate antiproliferative action on two renal cancer cell lines. The prostate cancer and some breast cancer cell lines were not sensitive. Nevertheless some breast cancer cell lines were apparently sensitive to CF3-substituted phenothiazine alkylureas. On the basis of these experiments one may postulate that in the case of insensitive cells an mdr-gene encoded multidrug resistance efflux pump is responsible for the resistance. The selectivity or organ cell specificity of the effective phenothiazines will be targeted for improvement in further studies, in order to avoid the general cytotoxic effects of "half mustard type" phenothiazines.

The in vitro antitumor assay of "half-mustard type" phenothiazines in screens of AIDS-related leukemia and lymphomas

Twelve different "half-mustard type" phenothiazines were newly synthesized and tested on seven AIDS-related lymphoma (ARL) tumor cell lines, one leukemia CCRF-CEM cell culture and five different lymphoma lines; RL, KD-488, AS283, PA682 and SU-DHL-7 cell lines. The alkylene-urea substituted phenothiazines affected the growth and inhibited the growth rate of AIDS-related lymphoma cells. The Cl-substituent at the 2-position was more effective than the CF3 substitution. In AIDS-related leukemia also the compounds with Cl at the 2-position with propylene or butylene linkers, -(CH2)3- and -(CH2)4-, respectively, were more effective than the CF3 substituted compounds. Two of the six phenothiazine-substituted alkyl-urea derivatives, i.e., 1-(2-chloroethyl)-3-(2-chloro-10H-phenothiazin-10-yl)propyl-l-urea (9, GI50 = -5.66, TGI = -5.04) and 1-(2-chloroethyl)- 3-(2-chloro-10H-phenothiazin-10-yl)butyl-1-urea (10, GI50 = -5.61, TGI = -5.12) exhibited antitumor activity for AIDS-related leukemia and five AIDS-related lymphomas. The trifluoromethyl-substituted derivatives were not as effective on AIDS-related tumor cell lines. Apparently, the substituent at the 2-position on the phenothiazine and the alkylene number of the linker attached to the nitrogen of the phenothiazine ring have an important role in the compound's antitumor effects on AIDS-related leukemia and lymphomas.

Attenuation of nitric oxide synthase induction in IRF-1-deficient glial cells

Nitric oxide (NO) produced by inducible nitric oxide synthase (iNOS) exerts inhibitory and cytotoxic effects on various cells including neuronal cells. Glial NO production, mediated via induction of iNOS, is thought to facilitate neuronal damage during cerebral ischemia. Recently, interferon regulatory factor-1 (IRF-1) has been reported to be an essential transcription factor for iNOS mRNA induction in murine macrophages. However, expression of IRF-1 and its role in the central nervous system have not been examined. In the present study, by using primary glial cell cultures from mice with targeted disruption of the IRF-1 gene, we investigated whether IRF-1 is involved in iNOS mRNA induction in glial cells. After stimulation with lipopolysaccharide and interferon-gamma, IRF-1 mRNA was strongly induced in wild-type (IRF-1 +/+) glial cells. iNOS mRNA induction and nitrite production in IRF-1 -/- glial cells were reduced as compared with those observed in IRF-1 +/+ glial cells. Diethyldithiocarbamate, a selective inhibitor of nuclear transcription factor kappa B (NF-kappa B), completely inhibited iNOS mRNA induction. These results suggest that not only NF-kappa B but also IRF-1 play important roles in iNOS mRNA induction in the central nervous system.

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.

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.

Changes in concentrations of methylglyoxal, D-lactate and glyoxalase activities in liver and plasma of rats fed a 3'-methyl-4-dimethylaminoazobenzene-rich diet

Donryu male albino rats were fed a diet containing 0.064% 3'-methyl-4-dimethylaminoazobenzene (MDAB) for 21 weeks. During the ensuing rat liver carcinogenesis, changes in the concentrations of methylglyoxal, D-lactate and glutathione as well as activities of glyoxalase I and II in liver and plasma were examined. After the start of the diet, hepatic contents of methylglyoxal and D-lactate increased to about 7 and 3 times that of the control, respectively. However, after 21 weeks the D-lactate content decreased from the elevated level, but remained at a higher level of 1.4 times the control. The hepatic glyoxalase I activity increased 1.2 to 1.7 times over the control during carcinogenesis, while glyoxalase II activity increased 160% during the precancerous state and decreased to 55% of control at 21 weeks. the hepatic level of reduced glutathione (GSH) increased and peaked after 4 weeks of the MDAB diet and decreased thereafter to 57% of the control level after 21 weeks. Both pyruvate and L-lactate levels increased in the liver and plasma of MDAB-fed rats when rats had obvious symptoms of hepatoma.

Inducible nitric oxide synthase following hypoxia in rat cultured glial cells

Nitric oxide (NO) produced by inducible nitric oxide (iNOS) exerts inhibitory and cytotoxic effects on various cells including neuronal cells. In the present study, we examined the ability of rat glial cells to produce NO following hypoxia/reoxygenation in vitro by measuring nitrite. The levels of nitrite produced in the cultured media of glial cells significantly increased after 12-h hypoxia but not after 0- and 6-h hypoxia. The NOS inhibitor, NG-monomethyl-L-arginine, decreased hypoxia-induced nitrite formation. In glial cells after hypoxia/reoxygenation, the iNOS and mRNA and protein expressions were detected by reverse-transcription polymerase chain reaction and by immunocytochemical analysis, respectively. The present study provides the first evidence that hypoxia induces NO production from glial cells. This hypoxia-induced, glial cell-derived NO may play a critical role in the pathogenesis of cerebral ischemia in vivo.

Effects of age on levels of cysteine, glutathione and related enzyme activities in livers of mice and rats and an attempt to replenish hepatic glutathione level of mouse with cysteine derivatives

There was a large statistically significant decrease in the hepatic level of cysteine and glutathione (GSH) in 24 month-old mice compared to young mice, while, cystine and glutathione disulfide (GSSG) contents in the liver did not differ between young and old mice. Activities of cystathionine gamma-lyase and beta-synthase in mouse liver of the 24 month-old group were significantly decreased. In rats, the hepatic levels of cysteine, cystine, GSH and GSSG exhibited no statistically significant change during aging to 30 month. As the rats matured, total hepatic activities of both cystathionine gamma-lyase and beta-synthase increased with maximum levels at 24 months of age and decreased to the same level found in 5 week old for the former and to 22% of that in 5 week old for the latter. Intraperitoneal administration of diethyl maleate to mice led to depletion of hepatic GSH. When N-acetylcysteine and a thiazolidine derivative were intravenously injected after diethyl maleate administration, the hepatic GSH level of mice was restored to the normal level.

Differential response in the release of hydrogen peroxide between astroglial cells and endothelial cells following hypoxia/reoxygenation

Hydrogen peroxide (H2O2) and lactate dehydrogenase (LDH) released from cultured astroglial cells (AGs) and brain endothelial cells (BECs) were measured following hypoxia/reoxygenation. AGs released H2O2 to the extracellular space from 8 h of hypoxia with the cellular injury indicated by LDH increase. In contrast, BECs released H2O2 at 4 h of hypoxia, prior to the LDH increase. These results suggest that AGs and BECs play different roles in production and metabolism of oxygen free radicals in the blood-brain barrier (BBB), and AGs may protect the BBB disruption from oxidative stress after hypoxia/reoxygenation.

Synthesis and antitumor activity of 1-[2-(chloroethyl)-3-(2-substituted-10H-phenothiazin-10-yl)alkyl- 1-urea s as potent anticancer agents

10-[N-(Phthalimido)alkyl]-2-substituted-10H-phenothiazines and 1-(2-chloroethyl)-3-(2-substituted-10H-phenothiazin-10-yl)alkyl-1- ureas were synthesized and found to have antiproliferative effects on human HEp-2 and L5178Y cell cultures. The multi-drug resistant subline of mouse lymphoma was sensitive to the reversal effects of some 10-[N-(phthalimido)alkyl]-2-substituted-10H-phenothiazines, while 1-(2-chloro-ethyl)-3-(2-substituted-10H-phenothiazin-10-yl)alkyl-1 -ureas were less effective but had a similar degree of antiproliferative effect on both cell lines.

Variability and phylogeny of the L1 capsid protein gene of human papillomavirus type 5: contribution of clusters of nonsynonymous mutations and of a 30-nucleotide duplication

We analyzed the variability and established the phylogeny of the L1 capsid protein gene of 33 isolates of human papillomavirus type 5 (HPV5) obtained from epidermodysplasia verruciformis patients from different continents. By comparing the sequences of a 419-bp fragment with those published for two Japanese isolates, we found 12.9% variable nucleotide positions, defining 25 variants with mutation rates ranging from 0.2 to 8.8%. Such a high intratypic diversity is unusual among HPVs. Nine of the 139 encoded amino acids were variable and 12 protein variants were identified. Fifteen of the 16 substitutions observed were clustered in two short regions. A 9-amino-acid insert, already reported for the Japanese HPV5b isolate, was found within one of the regions in five isolates. Our data support that the insert arose from the duplication of a 30-nucleotide sequence. Phylogenetic trees distributed the DNA variants into three subtypes (a to c) with a divergence higher than 4.5% and allowed the recognition of European and African lineages. By contrast with the trees based on the HPV5 E6 gene, HPV5a DNA variants and the HPV5b variants lacking the insert constituted a single group in the L1 amino acid tree, probably reflecting different levels of structural constraints for the HPV5 L1 and E6 proteins. In that respect, the short variable L1 sequences should represent less constrained regions.

Antitumor activity of phenothiazine-related compounds

One of the biggest challenges in health care is the fight against tumors. Some phenothiazines have antitumor activity on HEp-2 tumor cells. In this study, we tested the antitumor effects of three series such as 10-nonsubstituted phenothiazines, 10-[n-(phthalimido)alkyl]-2-substituted-10H-phenothiazines and 1-(chloroethyl)-3-(2-substituted-10H-phenothiazines-10-yl)alkyl-1-ureas with H, Cl and CF3 substitution at position C2. The TCID50 of phenothiazines was affected by the H, Cl and CF3 at C2. Trifluoromethyl derivative of phenothiazine showed potent (R = CF3, TCID50 = 4.7 micrograms) activity, whereas the chlorine derivative of phenothiazine (R = Cl, TCID50 = 62.5 micrograms) had a relatively weak effect. In the group of 10-[n-(phthalimido)alkyl]-2-substituted-10H-phenothiazines, 10-[3-(phthalimido)propyl]-10H-phenothiazine (R = H, n = 3, TCID50 = 11.5 micrograms), 10-[4-(phthalimido)butyl]-10H-phenothiazine (R = H, n = 4, TCID50 = 7.8 micrograms) and 10-[3-(phthalimido)propyl]-2-trifluoromethyl-10H- phenothiazine (R = CF3, n = 3, TCID50 = 11.5 micrograms) was very effective. On the other hand, TCID50 of 10-[3-(phthalimido)propyl]-2-chloro-10H-phenothiazine (R = Cl, n = 3, TCID50 = 75.0 micrograms), 10-[4-(phthalimido)butyl]-2-chloro-10H-phenothiazine (R = Cl, n = 4, TCID50 = 31.3 micrograms) and 10-[4-(phthalimido)butyl]-2-trifluoromethyl-10H-phenothiazine (R = CF3, n = 4, TCID50 = 50.0 micrograms) were about 4-8 times less effective than 10-[4-(phthalimido)butyl]-10H-phenothiazine (R = H, n = 4, TCID50 = 7.8 micrograms). Among six 1-(chloroethyl)-3- (2-substituted-10H-phenothiazin-10-yl)alkyl-1-ureas, two chlorine compounds such as 1-(2-chloroethyl)-3-(2-chloro-10H-phenothiazin-10-yl)propyl-1-urea (R = Cl, n = 3, TCID50 = 6.3 micrograms), 1-(2-chloroethyl)-3-(2-chloro-10H-phenothiazin-10-yl) butyl-1-urea (R = Cl, n = 4, TCID50 = 7.8 micrograms), and 1-(2-chloroethyl)-3-(2-trifluoromethyl-10H-phenothiazin-10-yl)buty l-1-ur ea (R = CF3, n = 4, TCID50 = 7.8 micrograms) were significantly active. Tests showed that the substitution at 2C position apparently affected the anti-HEp-2 tumor cell activity; that the length of the aliphatic side chain at 10N contributes to the anti-tumor activity; and that the TCID50 values of the derivatives with butylene group (-C4H8-) were lower than those with propylene group (-C3H6-) except 10-[4-(phthalimido) butyl]-2-trifuoromethyl-10H-phenothiazine and 1-(2-chloroethyl)-3-(2-chloro-10H-pheno-thiazin-10-yl) butyl-1-urea.

Induction of brain-derived neurotrophic factor (BDNF) and the receptor trk B mRNA following middle cerebral artery occlusion in rat

Middle cerebral artery (MCA) occlusion in halothane-anesthetized rats induced brain-derived neurotrophic factor (BDNF) and the receptor, trk B mRNA, in brain. In situ hybridization studies showed that BDNF and trk B mRNAs were induced in a widespread region of the ipsilateral cortex outside the infarct at 4 h following MCA occlusion. They were also induced in the bilateral hippocampi which are remote from the ischemic MCA region. These data show that changes in neurotrophic factor and receptor gene expressions can occur in the areas outside the infarct which could survive.

Immunomodulating activities on cellular cytotoxicity and the blast transformation of human lymphocytes by 10-[n-(phthalimido)alkyl-2-substituted-10H-phenothiazines and 1-(2-chloroethyl)-3-(2-substituted-10 H-phenothiazin-10-yl)alkyl-1-ureas

Phenothiazines, 10-[n-(phthalimido)alkyl-2-substituted-10H- phenothiazines, and 1-(2-chloroethyl)-3-(2-substituted-10H-phenothiazin-10-yl)alkyl-1- ureas were investigated for their effects on antibody-dependent cellular cytotoxicity (ADCC), natural killer (NK) cells and the blast transformation of human peripheral blood mononuclear cells. All of the compounds dose-dependently suppressed mitogen-stimulated T cell proliferation. In contrast, a strong enhancing effect on NK cell activity was detected mostly in the case of 1-(2-choroethyl)-3-(2-substituted-10H-phenothiazin-10-yl)alk yl-1-ureas and their related compounds. The stimulating effect directly influenced the NK cells and was demonstrated at all tested concentrations.

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.

[Left free wall rupture complicating acute myocardial infarction--a case report of surgical success by a new modified method]

The success rate of surgical treatment for blowout type free wall rupture of the left ventricle following myocardial infarction has been reported as 4 to 24%. A 64-year-old woman was admitted to our hospital for inferior acute myocardial infarction with cardiogenic shock. In the catheter laboratory, her hemodynamics disclosed electro-mechanical dissociation, and we had to perform an emergent operation there. In order to preserve left ventricular volume and reduce the risk of bleeding, we adopted a modified method using both patch and felt strip sandwich methods which obtained favorable result. The patient was sent to a rehabilitation hospital on the 43rd post operative day because of a mild cerebral complication and she is now doing well with only a slight speaking disturbance at a follow-up period of 10 months.

Biosynthesis of Poly(3-Hydroxyalkanoic Acid) Copolymer from CO(inf2) in Pseudomonas acidophila through Introduction of the DNA Fragment Responsible for Chemolithoautotrophic Growth of Alcaligenes hydrogenophilus

Pseudomonas acidophila is a bacterial strain producing a poly(3-hydroxyalkanoic acid) (PHA) copolymer from low-molecular-weight organic compounds such as formate and acetate. The genes responsible for PHA production were cloned in cosmid pIK7 containing a 14.8-kb HindIII fragment of P. acidophila DNA. With the aim of developing a means of producing a PHA copolymer from CO(inf2), cosmid pIK7 was introduced into a polymer-negative mutant of the chemolithoautotrophic bacterium Alcaligenes eutrophus PHB(sup-)4. However, the recombinant strain produced a homopolymer of 3-hydroxybutyric acid (polyhydroxybutyric acid) from CO(inf2). Since it was thought that the composition of the accumulated polymer might depend not on the PHA biosynthetic genes but on the metabolism of the host strain, a recombinant plasmid, pFUS, containing the genes for chemolithoautotrophic growth of the hydrogen-oxidizing bacterium A. hydrogenophilus was introduced into P. acidophila by conjugation. The recombinant plasmid pFUS was stably maintained in P. acidophila in the absence of chemolithoautotrophic or antibiotic selection. This pFUS-harboring strain possessed the ability to grow under a gas mixture of H(inf2), O(inf2), and CO(inf2) in a mineral salts medium, and PHA copolymer accumulation was confirmed by nuclear magnetic resonance spectral analysis. A gas chromatogram obtained by gas chromatography-mass spectrometry showed the composition of the polymer to be 52.8% 3-hydroxybutyrate, 41.1% 3-hydroxyoctanoate, and 6.1% 3-hydroxydecanoate. This is the first report of the production of a PHA copolymer from CO(inf2) as sole carbon source.

Reconstruction of dilated aortic annulus using short tubular Dacron graft for aortic root replacement by aortic homograft--a solution for size mismatch

To circumvent the problems associated with a dilated aortic annulus we first reduced the diameter of the annulus with a short section of Dacron graft and then implanted a smaller size homograft within the graft. This procedure was successfully performed for complete homograft aortic root replacement in a 25-year-old man with severe aortic insufficiency due to a dilated aortic annulus. The indication for homograft replacement can thus be widened, even to patients with a dilated aortic annulus.

Spinal malignant lymphoma appearing after radiation and chemotherapy of a pineal region tumor

The occurrence of malignant lymphoma in the pineal region is very rare. We experienced a case of pineal region tumor that was treated by radiation and chemotherapy. After 1 year, the tumor metastasized to the cauda equina and was operated on. The diagnosis was malignant lymphoma. Although the incidence of intracranial malignant lymphoma is known to be on the increase recently, malignant lymphoma should be considered in the differential diagnosis of pineal region tumors.

Modest truncation of the major capsid protein abrogates B19 parvovirus capsid formation

In vitro studies have suggested an important role for the minor capsid protein (VP1) unique region and the junction between VP1 and the major capsid protein (VP2) in the neutralizing immune response to B19 parvovirus. We investigated the role of the NH2-terminal region of the major structural protein in capsid structure by expressing progressively more truncated versions of the VP2 gene followed by analysis using immunoblotting and electron microscopy of density gradient-purified particles. Deletion of the first 25 amino acids (aa) of VP2 did not affect capsid assembly. Altered VP2 with truncations to aa 26 to 30, including a single amino acid deletion at position 25, failed to self-assemble but did participate with normal VP2 in the capsid structure. The altered region corresponds to the beginning of the beta A antiparallel strand. Truncations beyond aa 30 were incompatible with either self-assembly or coassembly, probably because of deletion of the beta B strand, which helps to form the core structure of the virus.