High-voltage capabilities of ultra-thin Nb2O5 nanosheet coated LiNi1/3Co1/3Mn1/3O2 cathodes

The surface coating of LiNi_1/3Co_1/3Mn_1/3 electrode with 1.1 nm Nb₂O₅ nanosheet enhanced the high voltage capability and long term stability of the charged state at 60 °C by reducing the contact area between electrode and electrolyte.

Manipulation of the small intestine as a cause of the increased inflammatory response after open compared with laparoscopic surgery

BACKGROUND

Laparoscopic surgery of the gastrointestinal tract involves a reduced immune response compared with open surgery. The aim of this study was to assess manual handling of the gut in open procedures as the principal cause of the enhanced immune response.

METHODS

Eighteen Landrace pigs underwent gastrectomy by three different methods: conventional open wound with bowel manipulation, laparoscopically assisted gastrectomy, and gastrectomy without manipulation using a combination of open wound and laparoscopic surgical devices. Local inflammatory changes were assessed by ascites formation, intestinal adhesion development and intestinal inflammatory gene expression. Associated systemic inflammatory changes were determined by measuring portal and systemic plasma endotoxin levels, plasma inflammatory cytokine levels, liver inflammatory gene expression and transaminase levels.

RESULTS

Significantly more postoperative intra-abdominal fluid and adhesions were seen in the open group. The expression of inflammatory cytokines was significantly greater in the intestine and liver in the open group. Portal and systemic levels of endotoxin, inflammatory cytokines and transaminases were also higher.

CONCLUSION

Manual handling of organs during gastrectomy is an important contributor to the molecular and humoral inflammatory response to surgery, supporting the use of minimally invasive techniques in gastrointestinal surgery.

Localization of MyoD, myogenin and cell cycle regulatory factors in hypertrophying rat skeletal muscles

AIM

MyoD, myogenin, proliferating cell nuclear antigen (PCNA) and cyclin-dependent kinase inhibitor p21 (p21) proteins are key molecules in inducing the growth of myogenic cells in vitro. However, it has not been determined which cell types express these factors in hypertrophying skeletal muscles in vivo.

METHODS

Using immunohistochemical techniques, we examined the spatial and temporal expression patterns of MyoD, myogenin, PCNA and p21 proteins in functionally overloaded rat plantaris muscles induced by ablation of the soleus and gastrocnemius muscles.

RESULTS

MyoD and myogenin were detected in myonuclei located inside the dystrophin-positive plasma membrane of myofibres, m-cadherin-positive satellite cell nuclei and nuclei located in the interstitial spaces between myofibres on days 1, 3, 5 and 7 post-surgery. Entry of satellite cells into the cell cycle was indicated by the expression of PCNA on day 3 post-surgery, and withdrawal from the cell cycle was observed by the expression of p21 in satellite cell nuclei on day 5 post-surgery. However, the expression of both PCNA and p21 in satellite cell nuclei disappeared on day 7 post-surgery.

CONCLUSION

These results indicate that proliferated satellite cell-derived myoblasts and undefined myogenic cells located in the interstitial spaces may contribute to an increase in myonuclear number and/or hyperplasia. Furthermore, we provide evidence that all of myonuclei, satellite cells and undefined myogenic cells express both MyoD and myogenin proteins. These results suggest that continual expression of MyoD and myogenin proteins in these cells is an essential molecular event which induces the successful hypertrophy of skeletal muscles.

Solution structure of micelle-bound H5 peptide (427-452): a primary structure corresponding to the pore forming region of the voltage dependent potassium channel

A 26-mer peptide with the sequence of the pore forming region (residues 427-452) of the Shaker K(+) channel (H5 region) was chemically synthesized. Analyses by CD and two-dimensional 1H NMR spectroscopy were used to investigate the structure of the peptide bound to SDS micelles in solution, which are commonly used in biophysical studies. The tertiary structure of the peptide as a monomer was composed of an alpha-helix (431-438), a turn (439-442), and random coils (427-430, 443-452), and was very similar to that of the pore forming region of the native K(+) channel from Streptomyces lividans determined by X-ray analysis. This result suggests that even an isolated peptide forms a native-like conformation for residues from 431 to 442, depending on its intrinsic amino acid sequence and the surrounding environment.

Gene expression of receptors for IL-6, LIF, and CNTF in regenerating skeletal muscles

The biological actions of interleukin-6 (IL-6), leukemia inhibitory factor (LIF), and ciliary neurotrophic factor (CNTF) are mediated via respective functional receptor complexes consisting of a common signal-transducing component, gp130, and other specific receptor components, IL-6 receptor alpha (IL-6R), LIF receptor beta (LIFR), and CNTF receptor alpha (CNTFR). IL-6, LIF, and CNTF are implicated in skeletal muscle regeneration. However, the cell populations that express these receptor components in regenerating muscles are unknown. Using in situ hybridization histochemistry, we examined spatiotemporal expression patterns of gp130, IL-6R, LIFR, and CNTFR mRNAs in regenerating muscles after muscle contusion. At the early stages of regeneration (from 3 hr to Day 2 post contusion), significant signals for gp130 and LIFR mRNAs were detected in myonuclei and/or nuclei of muscle precursor cells (mpcs) and in mononuclear cells located in extracellular spaces between myofibers after muscle contusion, but IL-6R mRNA was expressed only in mononuclear cells. At Day 7 post contusion, signals for gp130, LIFR, and IL-6R mRNAs were not detected in newly formed myotubes, whereas the CNTFR mRNA level was upregulated in myotubes. These findings suggest that the upregulation of receptor subunits in distinct cell populations plays an important role in the effective regeneration of both myofibers and motor neurons. (J Histochem Cytochem 48:1203-1213, 2000)

A novel NMR method for determining the interfaces of large protein-protein complexes

Identification of the interfaces of large (Mr > 50,000) protein-protein complexes in solution by high resolution NMR has typically been achieved using experiments involving chemical shift perturbation and/or hydrogen-deuterium exchange of the main chain amide groups of the proteins. Interfaces identified using these techniques, however, are not always identical to those revealed using X-ray crystallography. In order to identify the contact residues in a large protein-protein complex more accurately, we developed a novel NMR method that uses cross-saturation phenomena in combination with TROSY detection in an optimally deuterium labeled system.

Leukemia inhibitory factor, glial cell line-derived neurotrophic factor, and their receptor expressions following muscle crush injury

Using in situ hybridization histochemistry, we characterized the spatiotemporal gene expression patterns of leukemia inhibitory factor (LIF) and glial cell line-derived neurotrophic factor (GDNF), and their receptor components (LIFR, GFR-alpha1, RET) induced in muscle cells, intramuscular nerves, and motoneurons in the regeneration processes of both muscle cells and nerves following muscle contusion. Muscle contusion induced upregulation of GDNF and GFR-alpha1 mRNAs in Schwann cell-like cells in the intramuscular nerves and of LIFR mRNA in damaged muscle cells. LIFR, GFR-alpha1, and RET mRNA expressions in motoneurons were upregulated following muscle contusion. Muscle contusion also induced more rapid, prominent transactivations of GFR-alpha1 and RET genes in motoneurons than did sciatic nerve axotomy. These findings suggest that rapid and prominent upregulation of the receptor components for LIF and GDNF in motoneurons is important for the regeneration of intramuscular motor nerves damaged by muscle contusion.

Tissue expression of the S100 protein family-related MRP8 gene in human chorionic villi by in situ hybridization techniques

The present study examined the tissue-expression of MRP8 in human placenta using a biotinylated DNA-probe for in situ hybridization. During the first and second trimesters high level and synchronous expression of MRP8 was detected in cytotrophoblasts (Langhans' cells), placental-tissue macrophages (Hofbauer cells), fibroblast-like cells, endothelial cells and monocytic lineages in the foetal capillaries. The highest expression was seen in large and oval-shaped cytotrophoblasts and stromal-cell populations at around 8-11 weeks. At term placentas had low level MRP8 expression chiefly in the myelomonocytic lineages in foetal blood vessels. The peripheral monocytes in the maternal space also expressed MRP8 at high levels during the first and second trimesters, which subsequently decreased at term. We suggest three hypotheses based on these results; (1) The initial expression of MRP8 may occur in two cell lineages of extra-embryonic and intra-embryonic origin in the first two trimesters; (2) the cytotrophoblasts, placental-tissue macrophages and fibroblasts may play important roles in the production of placental hormones and the immuno-regulation of foetal acceptance; and (3) MRP8-expression may be synchronously inhibited once the trophoblasts and stromal cell-constituents have differentiated in the chorionic villi.

Expressions of a 68kDa-glycoprotein (GP68) and laminin in the mesodermal tissue of the developing mouse embryo

Immunohistochemistry revealed initial expression of the stage-specific glycoprotein, GP68, in various mesenchymal tissue substructures of mouse embryos. During the 11-15th days of gestation, GP68 was localized in the primitive meninges, chondroblasts and perichondrium of pre-cartilaginous vertebral bodies and ribs, connective tissue cells of the dermis, the epicardium and endocardium of the heart, the epimysium and perimysium of skeleton musclature, and the basement membranes of splanchnic organs. Double staining for laminin expression indicated coincidental expression in identical tissue substructures. However, laminin was expressed in days 10-18 embryos and the neonate. Therefore, GP68 is coincidentally expressed with laminin in mesenchymal tissues between the 11th and 15th day of gestation, and may play a role as a laminin-associated protein. In the light of these results, a hypothesis concerning the relationship between these two proteins and the mechanisms of non-integrin laminin-associated proteins during normal embryogenesis is discussed further.

Localization of leukemia inhibitory factor and interleukin-6 messenger ribonucleic acids in regenerating rat skeletal muscle

In the present study, we characterized both temporal and spatial expression patterns of leukemia inhibitory factor (LIF) and interleukin-6 (IL-6) messenger ribonucleic acids (mRNAs) in injured skeletal muscle using in situ hybridization. LIF and IL-6 mRNAs were expressed in mononucleated cells and damaged muscle cells. Further, signals for LIF mRNA were also detected in Schwann cell-like cells of intramuscular nerves. These results suggest that the earliest events involved in the repair of injured muscles and nerves may be triggered by these cytokines.

Cellular characterization of the 91kDa-ectopic ascitic antigen sharing antigenicity with MRP8 in the human placenta as revealed by immunoelectron microscopical colloidal-gold techniques

Cellular characterization of the 91kDa-ectopic ascitic protein that exhibits pregnancy-associated and tumour-related dynamics has been examined in the human placenta using an electron microscopic immunocolloidal-gold technique. This protein was initially isolated from the ascitic fluids of a patient suffered from ovarian and uterine cancers with mixed mesodermal tumours, and determined to be sharing antigenicity with the 28kDa-oncodevelopmental protein and a calcium-binding protein; MRP8/CFA, respectively. Placentas obtained were divided into three groups by their gestational periods. Small chorionic villous tissues were embedded in Lowicryl K4M resin or Epon 812 resin. Specific and higher labelings by gold-particles were obtained in sections of Lowicryl resin and, then, recognized in mesenchyme-derived cells and/or myeloid lineages; such as placental tissue macrophages (Hofbauer cells), fibroblasts, foetal myelomonocytic cells including endothelial cells, etc., in the first and second trimesters. So far, the pattern of antigenic appearances changed depending on the stage of gestation. On the other hand, 91kDa-protein was also determined in the syncytiotrophoblast, but not in cytotrophoblasts at whenever been examined. It is assumed that the antigenic expression in syncytiotrophoblasts might be reflected to be absorbed or incorporated from those of foetal or maternal origins, and the antibody used in this study should be sensitive to the antigenic epitope derived from those of myeloid lineages. In the light of these results, hypotheses concerning mechanisms of both transplacental permeability of substances by the placental barrier and cell/tissue differentiation by calcium-binding (and/or -depending) proteins such as 91kDa-protein, MRP8, etc.; presumable the S-100 protein family, are discussed further.

Immunolocalization of 91 kDa ascitic protein in the human placenta

A 91 kDa protein, sharing antigenicity with a pregnancy-associated antigen, was isolated from the ascitic fluid of a patient suffered from the gynaecological malignant neoplasms. It was revealed in the human placenta by immunocytochemical techniques, and found to be localized in the stroma, including a fibrous network, fibroblasts and the Hofbauer cells of the terminal and stem villi in the first trimester. Immunoreactive staining was also found in macrophage-like cells, presumable the precursor of the Hofbauer cell, in the stem villi of placenta. It is assumed that macrophage-like cells containing the protein would be originated from the extraembryonic mesoderm or blood vessels, and then migrated to the stroma of terminal villi. During the second trimester, the protein was observed in numerous vesicles among the syncytial trophoblasts. The density of these immunoreactive vesicles and the cytoplasm of Hofbauer cells was rapidly increased with gestational stages, whereas it was gradually reduced towards the late-second trimester. The highest labellings occurred at around 17 weeks or later. On the other hand, at term, the protein was mainly observed in numerous villous blood vessels including endothelial cells. In the light of these results, a hypothesis concerning mechanisms of transplacental permeability of the protein by the placental barrier is discussed further.

Localization of myogenin, c-fos, c-jun, and muscle-specific gene mRNAs in regenerating rat skeletal muscle

It has been suggested that myogenin is an important factor for the differentiation of myoblasts and that its function in myogenesis is regulated by proto-oncogenes in in vitro experiments. We have characterized the spatial and temporal expression patterns of myogenin, c-fos, c-jun, and muscle creatine kinase mRNAs during the skeletal muscle regeneration process using in situ hybridization histochemistry. Myogenin transcripts are first detected in the myonuclei/nuclei of satellite cells at 6 h after induction of regeneration. Myogenin mRNA is expressed in desmin-positive myoblasts, yet no muscle creatine kinase mRNA is detected in this cell type. Both the muscle creatine kinase and myogenin mRNAs are expressed in the newly formed myotubes, but not at earlier stages. Transcripts for c-fos and c-jun mRNAs are expressed first in the myonuclei/nuclei of satellite cells at 3 h post-trauma. c-jun mRNA is expressed in both myoblasts and myotubes, while c-fos mRNA was not detected in these cells. These results suggest that myogenin plays important role in the regeneration of injured muscle and that c-jun and c-fos may have different roles in this process.

Changes of vinculin and extracellular matrix components following blunt trauma to rat skeletal muscle

The purpose of the present study was to determine changes in the localization of vinculin, Type IV collagen, laminin, and fibronectin during the damage-repair process in the skeletal muscle over several days following acute blunt trauma. A single blunt trauma to the gastrocnemius muscle of the rat was induced by applying 1.57 J of kinetic energy to one leg. By day 2 after trauma, vinculin had disappeared rapidly from the intracellular submembraneous region corresponding to the costamere, whereas Type IV collagen and laminin persisted around the degenerating myofibers (corresponding to the basement membrane). Fibronectin could be observed filling the widened endomysium and in the ruptured myofibers. In the early phase of muscle regeneration (day 5 after trauma), newly synthesized vinculin, Type IV collagen, and laminin formed ring-like structures around the regenerating myotubes. Fibronectin could also be observed filling the widened endomysium around the regenerating myotubes. Further, when small newly formed or splitted myofibers were observed in the areas of regenerating myofibers (day 10 after trauma), vinculin, Type IV collagen, laminin, and fibronectin were localized in specialized regions corresponding to the costamere, basement membrane, and endomysium. These results demonstrated that restoration of the costamere, basement membrane, and endomysium are essential to the maturation of regenerating myofibers after injury.

Secretory pathway of vitellogenesis in the liver of the cockerel as revealed by immuno-gold and computer-assisted digitization techniques

The protein A-gold immunocytochemical technique was used to localize the secretory pathway of oestradiol-induced vitellogenin in hepatic parenchymal cells of the cockerel. Liver was removed from experimental birds on the 1st, 4th and 8th day following oestradiol-treatment, and embedded in Lowicryl K4M resin cured at -20 degrees C. In selected electron micrographs the fractional surface area of each of the intracellular compartments was measured by the computer-assisted digitization technique. Labelling was detected over the cisternae of the rough endoplasmic reticulum (RER), the Golgi apparatus, the immature secretory vacuoles (ISV) including condensing vacuoles and the mature secretory vacuoles (MSV). Counts of the gold particles demonstrated an increasing concentration which progressed in the order RER less than Golgi less than ISV less than MSV and identified the secretory pathway of the protein. The highest density of labelling was obtained on the 4th day, when vitellogenin reaches its peak activity. Autophagic activity (or crinophagy) was also found in lysosomes and its labelling intensity increased daily. A hypothesis concerning the secretory pathway of non-stored proteins by the liver is discussed further.

Immunoelectron microscopical demonstration of egg-yolk plasma precursor vitellogenin in the hepatocyte of oestradiol-treated cockerels

Vitellogenin has been localized at the electron microscopical level in the liver of the cockerel using a colloidal gold technique. White leghorn cockerels were treated with 17 beta-oestradiol to induce vitellogenesis. Pieces of liver were removed from control and experimental birds on the 4th and 8th days following hormone treatment, and embedded in Lowicryl K4M. Vitellogenin was isolated from the plasma of oestradiol-treated cockerels, and the antibody to it elicited in rabbits and made vitellogenin-specific by affinity chromatography on lipovitellin-Sepharose columns. At the light microscopical level, the intensity of immunohistochemical staining was considerably above background levels in oestradiol-treated cockerels. At the electron microscopical level, gold particles indicating antigenic sites of vitellogenin were largely confined to the rough endoplasmic reticulum, Golgi apparatus, immature and lysosomes and phagosomes within hepatocytes and sinusoidal cells respectively. These observations strongly suggest that the intracellular pathway of vitellogenin secretion in chicken hepatocytes under the experimental conditions studied involves external stimuli and secretory vacuoles. The labelling of lysosomes may reflect catabolic turnover (crinophagy).

Immunoelectron microscopical demonstration of endogenous avidin in secretory granules of the hen oviduct mucosa: a preliminary study

The localization of avidin in the oviduct of the laying hen was investigated using ultrastructural immunoperoxidase techniques. Endogenous avidin was localized in secretory granules of both tubular gland cells and non-ciliated single epithelial cells in the magnum mucosa. These immunospecific granules were electron-dense and heterogeneous with a patchy core and dense peripheral region, especially in acinar cells. The size varied from small to large in the gland cells (500-2200 nm in diameter) and remained small in the epithelial cells (180-720 nm). Columnar epithelial cells containing avidin granules strongly resembled the protodifferentiated tubular gland cells appearing in the magnum mucosa of chicks artificially pretreated with ovarian hormones. On the other hand, no avidin was observed in either epithelial goblet cells or ciliated cells in adult hens, although both cell types were shown to produce avidin in young chicks when synchronized by the administration of progesterone. The present results parallel those obtained with biotinylated enzyme affinity methods in our previous cytochemical study. Therefore, avidin is one of the proteins produced and stored in the secretory granules of the tubular gland cells and protodifferentiated acinar cells present in the epithelial layer of the laying hen oviduct. It is not present in goblet cells. Although the initiation of a synthesis may be triggered by progesterone, it is still not clear whether different hormone dependent proteins are localized in the same granules in both the adult hen and the immature chick.

Ultrastructural observations of chorionic villi at term in diabetic women

An electron microscopic study has been performed on placentas from women with maternal diabetes. None of the patients had suffered from any of the hypertensive complications of pregnancy (White's class A). Most villous trophoblasts were morphologically normal and showed features suggestive of normal or increased synthetic transport and excretory activity. These cells appeared to be far more "active" than their counterparts in normal term placentas in that many contained Golgi bodies that were often associated with membrane-bound osmiophilic vesicles. Focal thickening of the trophoblastic basement membrane was seen. The endothelial capillaries contained an excessive number of microfibrillae and micropinocytotic vesicles and appeared unduly immature. Very abundant osmiophilic granules were seen in many villous components, such as syncytiotrophoblasts, stromal fetal endothelial cells, pericytes, Hofbauer cells and fibroblasts. These may have been concerned in the cross-transportation of materials between the maternal intervillous space and the fetal capillaries, rather than the incorporation of substances within them. These morphological changes did not show, however, any specific, constant or uniform pattern of abnormality attributable maternal diabetes.

Endogenous avidin found in the magnum gland of the hen oviduct. Comparative cytochemical studies utilizing both biotinyl-peroxidase and immunoperoxidase methods

The location of endogenous avidin was studied cytochemically in the magnum tissue of the oviduct of laying hens. Two methods, based on an interaction of avidin-biotin with biotin hydrazide-peroxidase (B-HRP) as an affinity reagent, and on an immunoperoxidase technique, were tested by morphological analysis. The data obtained by both methods showed that in the magnum B-HRP is a strictly substitutive reagent for endogenous avidin. Avidin was clearly demonstrated in large amounts in the secretory granules of some epithelial cells and tubular gland cells, but was absent from mucous cells, the goblet cells, which had been believed to be the location of avidin production, and from ciliated cells. These granules had previously been demonstrated by both electron-microscopic cytochemical techniques. Especially in acinar cells, they were nonhomogeneous with a speckled core and a dense peripheral part. They ranged in size from 500 to 2200 nm in diameter in the gland and 180 to 720 nm in the epithelium. Columnar epithelial cells containing avidin granules had a strong resemblance to those of the protodifferentiated tubular gland cells in the magnum of chicks pretreated with daily estrogen or estrogen plus progesterone, and might have migrated towards the acinus as substitutional secretory cells. Therefore, the acinar cells of the magnum, considered to be composed of several secretory protein-producing systems, are dependent on estrogen and/or progesterone in the oviduct of the laying hen.