Use of a biphasic graft constructed with chondrocytes overlying a beta-tricalcium phosphate block in the treatment of rabbit osteochondral defects

To evaluate the ability of a biphasic construct to repair osteochondral defects in articular cartilage, plugs made of chondrocytes in collagen gel overlying a resorbable porous beta-tricalcium phosphate (TCP) block were implanted into defects in rabbit knees. The repair tissue was evaluated at 8, 12, and 30 weeks. Eight weeks after implantation of the biphasic construct, histologic examination showed hyaline-like cartilage formation that was positive for safranin O and type II collagen. At 12 weeks, most of the beta-TCP was replaced by bone, with a small amount remaining in the underlying cartilage. In the cell-seeded layer, the newly formed middle and deep cartilage adjacent to the subchondral bone stained with safranin O, but no staining was observed in the superficial layer. In addition, cell morphology was distinctly different from the deep levels of the reparative cartilage, with hypertrophic cells at the bottom of the cartilaginous layer. At 30 weeks, beta-TCP had completely resorbed and a tidemark was observed in some areas. In contrast, controls (defects filled with a beta-TCP block alone) showed no cartilage formation but instead had subchondral bone formation. These findings indicate that beta-TCP-supported chondrocytes in collagen gel can partially repair isolated articular cartilage osteochondral defects.     

Complete Nucleotide Sequence,Genome Organization and Phylogenic Analysis of the Canine Calicivirus

The complete genomic sequence of canine calicivirus (CaCV) isolated from feces of a dog with diarrhea was determined. The CaCV genome, a positive-sense single-stranded RNA, contained 8513 nucleotides excluding the poly(A) tail and was longer than that of any other calicivirus strain with a completely known sequence. There were three open reading frames (ORF1, nt 12–5801; ORF2, nt 5805–7880; and ORF3, nt 7877–8278). ORF1 encoded a polyprotein (calculated M _r of 214,802) which had the conserved motifs of non-structural proteins of other caliciviruses and picornaviruses. Regions containing characteristic motifs in the non-structural polyprotein of CaCV showed highest similarity with those of the species Feline calicivirus and Vesicular exanthema of swine virus in the genus Vesivirus. Phylogenic analysis indicated that CaCV formed a distinct branch within the genus. Our results strongly suggested that CaCV is a new species in the genus Vesivirus.     

Role of nitric oxide in host defense in murine salmonellosis as a function of its antibacterial and antiapoptotic activities

Host defense functions of nitric oxide (NO) are known for many bacterial infections. In this study, we investigated the antimicrobial effect of NO in murine salmonellosis by using inducible NO synthase (iNOS)-deficient mice infected with an avirulent or virulent Salmonella enterica serovar Typhimurium strain. All iNOS-deficient mice died of severe septicemia within 6 days after intraperitoneal injection with an avirulent strain (LT2) to which wild-type mice were highly resistant; 50% lethal doses (LD(50)s) of the LT2 strain for iNOS-deficient and wild-type mice were 30 CFU and 7 x 10(4) CFU, respectively. Lack of NO production in iNOS-deficient mice was verified directly by electron spin resonance spectroscopy. Bacterial yields in liver and blood were much higher in iNOS-deficient mice than in wild-type mice throughout the course of infection. Very small amounts of a virulent strain of serovar Typhimurium (a clinical isolate, strain Gifu 12142; LD(50), 50 CFU) given orally caused severe septicemia in iNOS-deficient animals; wild-type mice tolerated higher doses (LD(50), 6 x 10(2) CFU). Histopathology of livers from infected iNOS-deficient mice revealed extensive damage, such as diffuse hepatocellular apoptosis and increased neutrophil infiltration, but livers from infected wild-type mice showed a limited number of microabscesses, consisting of polymorphonuclear cells and macrophages and low levels of apoptotic change. The LT2 strain was much more susceptible to the bactericidal effect of peroxynitrite than the Gifu strain, suggesting that peroxynitrite resistance may contribute to Salmonella pathogenicity. These results indicate that NO has significant host defense functions in Salmonella infections not only because of its direct antimicrobial effect but also via cytoprotective actions for infected host cells, possibly through its antiapoptotic effect.     

Production and characteristics of strain common antibodies against a synthetic polypeptide corresponding to the C-terminal region of potato virus Y coat protein

Comparing the predicted amino acid sequence between two Japanese potato virus Y (PVY) strains, necrotic strain and ordinary strain, it was found that the C-terminal regions (H₂N-HTTEDVSPSMHTLLGVKNM-COOH) of the coat proteins in the two strains were completely conserved. The conserved amino acid sequence was also found in the C-terminal region coat protein of PVY-36, a strain which did not react with monoclonal antibodies specific to the necrotic and the ordinary strain respectively. Antibodies were produced against a synthetic polypeptide PVY-C19 consisting of 19 amino acids, which correspond to the C-terminal region of the coat protein, using 4 coupling combinations of polypeptide PVY-C19 to protein carriers. Carrier-free polypeptides and those coupled to ovalbumin with ECDI (ethyl-dimethylaminopropyl carbodiimide) produced high titer of antibodies and detected PVY strains from PVY-infected plants by Western blot analysis and by ELISA.     

The molecular basis of dichromatic color vision in males with multiple red and green visual pigment genes.

We investigated the genotypic variation in 50 red-green color vision deficient males (27 deuteranopes and 23 protanopes) of middle European ancestry who possess multiple genes in the X-linked photopigment gene array. We have previously shown that only the first two genes of the array are expressed and contribute to the color vision phenotype. Therefore, the hypothesis is that the first two genes possessed by multigene-dichromats encode pigments of identical or nearly identical spectral sensitivity: one gene normal (R or G) and the other a hybrid (G/R or R/G). The spectral sensitivities of the encoded pigments were inferred from published in vitro and in vivo data. The color vision phenotype was assessed by standard anomaloscopy. Most genotypes (92%) included hybrid genes whose sequence and position and whose encoded pigment correlated exactly with the phenotype. However, one and possibly two of the protanopes had gene arrays consistent with protanomaly rather than protanopia, since two spectrally different pigments may be encoded by their arrays. Two of the deuteranopes had only R- and G-photopigment genes, without any detectable G/R-hybrid genes or any as-of-yet identified point mutation or coding/promoter sequence deletions. Further, an unexpectedly high number of multigene-deuteranopes (11%) had the C203R mutation in their most upstream G-pigment gene, suggesting a founder effect of middle European origin for this mutation. About half of the protanopes possessed an upstream R/G-hybrid gene with different exon 2 coding sequences than their downstream G-pigment gene(s), which is inconsistent with published data implying that a single amino acid substitution in exon 2 can confer red-green color discrimination capacity on multigene-protans by altering the optical density of the cones.     

Neural circuit-dependent odor adaptation in C. elegans is regulated by the Ras-MAPK pathway

The molecular machinery that mediates odor adaptation in the olfactory neurons is well documented in various animal species. However, types of adaptation that depend on neural circuits are mostly unexplored. We report here that the Ras-MAPK pathway is essential for such a type of odor adaptation, called early adaptation, in C. elegans. Early adaptation requires a pair of AIY interneurons, which receive synaptic inputs from olfactory neurons. Mutants of the Ras-MAPK pathway show defects in early adaptation. Continued exposure to an odorant causes activation of MAP kinase not only in the olfactory neurons, but also in the AIY interneurons. While activity of the Ras-MAPK pathway in the olfactory neurons is important for odor perception, its activity in the AIY interneurons is important for odor adaptation. Our results thus reveal a dual role of the Ras-MAPK pathway in sensory processing in the nervous system of C. elegans.     

ULTRASTRUCTURAL CHANGES OF THE DOG MYOCARDIUM IN EXTRACORPOREAL CIRCULATION

The effects of the cardiopulmonary bypass circulation on the cardiac muscle cells were studied electron microscopically. Subendocardial hemorrhage was commonly recognized in both ventricles. However, it appeared earlier and more severely in the right ventricle than In the left ventricle. Clear flocculent areas containing numerous filamentoue structures were originated from degradation of myofibrils. Degradation of myofibrils occurred within 1 hour after bypass circulation. Degenerative changes of myocardial cells such as zonal lesions, contraction bands and swelling or condensation of mitochondria appeared in both ventricles. Damages of myocardial cells In right ventricular wall were more severer as compared with those in the left throughout the period of observation. ACTA PATH. JAP. 27: 435–445, 1977.