Youngjoon Ryu

The relation between glycogen, lactate content and muscle fiber type composition, and their influence on postmortem glycolytic rate and pork quality

This study examined the relation between glycogen, lactate content and muscle fiber type composition, and evaluated their influence on postmortem glycolytic rate and meat quality. Muscle samples were classified based on their glycogen and lactate content at 45min postmortem. Muscles with low glycogen and high lactate levels showed low muscle pH(45min) and high R-values. However, muscles with low glycogen and lactate levels showed normal rates of postmortem glycolysis and normal meat quality. On the other hand, muscles with high glycogen and lactate content showed rapid postmortem glycolysis, paler surface color, higher drip loss, and higher extents of protein denaturation than muscles with high glycogen and low lactate content. These results may be partially explained by muscle fiber type composition. Muscles with low glycogen and lactate content at early postmortem are composed of significantly higher fiber type I and lower fiber type IIB as compared to muscles with high glycogen and lactate content.

Comparing the histochemical characteristics and meat quality traits of different pig breeds

The purpose of this study was to compare the muscle histochemical characteristics and meat quality traits between Berkshire, Landrace, Yorkshire, and crossbred pigs. A total of 594 pigs were evaluated. A clear difference between histochemical properties was observed from the results for fiber type composition. In Berkshire pigs, the area percentage of type I fibers was higher (P<0.001) and that of type IIb fibers was lower (P<0.05) than those of other breeds. The muscle pH(45min) and pH(24h) were significantly higher in Berkshire pigs. Drip loss and color parameters were significantly different between the breeds (P<0.001). The Berkshire pigs, which showed the highest muscle pH and lowest drip loss and L(∗) values, contained a significantly higher percentage of type I fibers than the other breeds. By comparing the fiber type compositions of the different breeds, the results imply that the longissimus dorsi muscle of Berkshire pigs is more oxidative than that of other breeds. A high pH value in Berkshire pigs is due to a high percentage of type I fibers and a low percentage of type IIb fibers. Based on these results, we conclude that muscle fiber composition can explain in parts the variation of meat quality across and within breeds.

Influence of myosin heavy- and light chain isoforms on early postmortem glycolytic rate and pork quality

This study addressed the influence of the content of myosin heavy- (MHC) and light chain (MLC) isoforms on early postmortem glycolytic rate and meat quality traits in the porcine longissimus muscle. The fast-glycolysing group showed lower contents of MHC slow and MLC 1s isoforms (P<0.05), and higher MHC fast isoform contents than the normal-glycolysing group (P<0.05). The MHC fast/slow ratio was correlated with lactate content (r=0.41) and early postmortem muscle pH (r=-0.51), and the content of the MLC 1s isoform was negatively correlated with lactate content and glycolytic potential (r=-0.38 and -0.36, respectively). Hence, both the MHC and MLC isoforms did influence metabolite contents, thus also affecting glycolytic rate, and suggested that the myosin isoforms, in particular the MHC isoforms, might also have some bearing on the extent of protein denaturation and pork quality during the early postmortem period.

Variations in metabolite contents and protein denaturation of the longissimus dorsi muscle in various porcine quality classifications and metabolic rates

The purpose of the present study was to investigate the variations in metabolite contents and muscle protein denaturation in various porcine quality classifications and metabolic rates. A total of 226 crossbred pigs were evaluated. Samples were classified based on muscle pH(45min) and R-value into fast or normal glycolysing group. Drip loss and lightness (L*) were used to assign samples as PSE, RSE, or RFN pork. Normal-glycolysing PSE pork contained an exceptional amount of initial glycogen and the high level of lactate at 24h postmortem (PM). The initial levels of metabolites related closely with muscle pH, R-value and protein solubility at 45min PM. The fast glycolysing group exhibited severe protein denaturation during the early postmortem period, and among them, fast-glycolysing PSE pork exhibited most pronounced protein denaturation. Via examination of each sarcoplasmic protein fraction, it was found that the bands for fructose-6-phosphate kinase, creatine kinase, triosephosphate isomerase, and myokinase were generally more evident as fainter bands in the fast-glycolysing pigs.

The angiogenic capacity from ligamentum flavum subsequent to inflammation: a critical component of the pathomechanism of hypertrophy.

Study Design. In vitro study about angiogenic potentiality of ligamentum flavum (LF) cells using coculture of human lumbar LF cells and activated macropage-like THP-1 cells. Objective. To test our hypothesis that activated LF, which was exposed to inflammation, induces angiogenesis, thus resulting in hypertrophy. Summary of Background Data. Inflammatory reactions after mechanical stress produce fibrosis and scarring of the LF that result in hypertrophy, a major pathological feature of spinal stenosis. This study evaluated the roles of LF cells in the pathomechanism of hypertrophy, focusing on angiogenesis. Methods. To determine their response to the inflammatory reaction, human LF cells were cocultured with phorbol myristate acetate-stimulated macrophage-like THP-1 cells. The conditioned media were assayed for tumor necrosis factor (TNF)-&agr;, interleukin (IL)-1&bgr;, IL-6, IL-8, vascular endothelial growth factor (VEGF), and transforming growth factor (TGF)-&bgr;1. Naïve and macrophage-exposed LF cells that responded to TNF-&agr;/IL-1&bgr; were compared using the same outcome measures. Hypertrophied LF tissue was stained by TGF-&bgr;1 primary antibody using immunohistochemical method. Results. Larger quantities of IL-6, IL-8, and VEGF were secreted by cocultured cells than by macrophages alone and LF cells alone combined. Prior macrophage exposure increased the secretion of IL-8 and VEGF in response to TNF-&agr;/IL-1&bgr; stimulation whereas IL-6 production was increased in response to IL-1&bgr;. The coculture appeared to increase TGF-&bgr;1 secretion but the level was lower than that for macrophage-like cells alone and LF cells alone combined. Conclusion. LF cells interact with macrophage-like cells to produce angiogenesis-related factors except TGF-&bgr;1. Activated LF cells that have been exposed to macrophage, can impact the inducement of angiogenesis-related factors, suggesting that fibrosis and scarring during inflammatory reaction is the major pathomechanism of LF hypertrophy.

Effectiveness of Silver-enhanced In Situ Hybridization for Evaluating HER2 Gene Status in Invasive Breast Carcinoma: A Comparative Study

BACKGROUND AND AIMS HER2 gene amplification occurs in breast cancers and has implications for treatment and prognosis. Recently, a new direct evaluation technique, silver enhanced in situ hybridization (SISH) was developed for evaluating HER2 gene status. This study was performed to evaluate the SISH technique for clinical use by comparing it to that of fluorescence in situ hybridization (FISH) and immunohistochemistry (IHC). METHODS We studied 543 cases of excised breast specimens diagnosed as invasive ductal carcinoma by IHC, FISH, and SISH using a tissue microarray. IHC, FISH, and SISH results were interpreted according to the American Society of Clinical Oncology/College of American Pathologists guidelines. A total of seven English studies that reported the concordance rates of SISH and BDISH compared to FISH published before July 2011 were retrieved. RESULTS The consensus concordance rate between SISH and FISH was 96.69% (kappa value = 0.9175). The pooled sensitivity was 0.94 [95% confidence interval (CI) = 0.91-0.97], and the pooled specificity was 0.98 (95% CI = 0.96-099) in a meta-analysis of the retrieved studies and this study. Area under the receiver operating characteristics curve was 0.9906. CONCLUSIONS SISH technique is an effective modality and is comparable with FISH for evaluating HER2 gene amplification in patients with breast carcinoma.

Carcinosarcoma in the Cecum

Carcinosarcoma of the colon is rare. Seventeen cases have been reported in the English literature. Most cases occurred in the left side of the colon. Indeed, there is only one reported case of cecal carcinosarcoma. Carcinosarcoma has a tendency to distantly metastasize and shows dismal prognosis. We report a case of carcinosarcoma in the cecum and review the literature describing colonic carcinosarcoma.