Effects of L-arginine on spontaneous contraction of the rat portal vein

The effects of L-arginine on spontaneous contraction of endothelium-denuded longitudinal preparations of the rat portal vein were studied. L-arginine increased the frequency of spontaneous contraction concentration-dependently between 10 microM and 1 mM. Changes in contraction amplitude and duration were not remarkable. D-arginine had a negligible effect on spontaneous contraction. N(omega)-nitro-L-arginine (1 mM) did not affect spontaneous contraction or the response to L-arginine. Addition of N(G)-monomethyl-L-arginine (1 mM), l-lysine (1 mM) or N-ethymaleimide (0.1 mM) increased the frequency of spontaneous contractions and inhibited the effect of L-arginine. Glibenclamide (10 microM) did not affect spontaneous contraction or the response to L-arginine. Spontaneous increase in concentration of intracellular Ca2+, estimated as the ratio of Fura-PE3 fluorescence occurred synchronously with spontaneous contraction. Spontaneous increase in concentration of intracellular Ca2+ occurred more frequently in the presence of L-arginine (1 mM). L-arginine (1 mM) also increased the number of action potential bursts/min in the longitudinal smooth muscle layer. L-arginine (1 mM) also depolarized cell membranes. This study indicates that L-arginine increases the frequency of spontaneous contraction of longitudinal muscle in the rat portal vein by membrane depolarization through mechanisms that do not involve nitric oxide or the inhibition of ATP-sensitive K+ channels.     

Effects of mandibular advancement on supine airway size in normal subjects during sleep

STUDY OBJECTIVES: To examine changes in the upper-airway dimension and its surrounding structures induced by mandibular advancement during sleep. DESIGN: Eleven nonapneic adult males participated in the study. A set of supine lateral cephalograms was taken for each subject at the end of expiration during stage 1 and 2 non-rapid-eye-movement sleep with and without a Klearway appliance (Great Lakes Orthodontics, NY, USA), which was adjusted to 67% of the maximum protrusion position. The Wilcoxon signed-rank test was used to compare changes in the anteroposterior width of the upper airway and the positions of the hyoid bone and third cervical vertebra with and without the appliance. SETTING: N/A. PATIENTS OR PARTICIPANTS: N/A. INTERVENTIONS: N/A. MEASUREMENTS AND RESULTS: The amount of jaw opening was significantly increased by wearing the titratable oral appliance, and the mandibular symphysis moved backward. The sagittal dimension of the superior pharyngeal airway was significantly increased; however, no significant changes were found in the middle and inferior pharyngeal airway. Significant posterior displacement of the hyoid bone and third cervical vertebra was seen. Moreover, significant inferior displacement of the hyoid bone was also seen. The relationship among the mandibular symphysis, the hyoid bone, and the third cervical vertebra remained constant. CONCLUSIONS: Mandibular advancement significantly increases the size of the upper airway in the velopharynx and results in posteroinferior displacement of the hyoid bone and posterior displacement of the third cervical vertebra during sleep.     

SYNDROME OF THE SEA-BLUE HISTIOCYTE —The First Case Report in Japan and Review of the Literature—

A case of the syndrome of sea-blue histiocyte is presented in a 53-year-old Japanese woman, which is the first recorded case in Japan. The patient had hepatosplenomegaly, bleeding manifestations, mild thrombocytopenia, fatty metamorphosis and cirrhosis of the liver, as well as abnormal serum lipid profiles. Her parents were consanguineous and her maternal grandmother with hepatomegaly died of hepatic failure. Histologically, peculiar histiocytes containing numerous, intracytoplasmic sea-blue stained granules on May-Giemsa stain were demonstrated in biopsy materials of the bone marrow, lymph node and liver. The sea-blue granules in these histiocytes proved to have histochemical staining characteristics of lipogenic ceroid-like pigment. Ultrastructurally, these granules showed membrane-bound, pleomorphic inclusions of heterogeneous nature, including electron-dense amorphous or variegatedly osmiophilic, frequently laminated materials. Enzyme cyto-chemically, localization of acid phosphatase activity was demonstrated in and around the intracytoplasmic inclusions. With regard to the pathogenesis of the sea-blue histiocytes in this case, it may be suggested that the existence of the abnormality in lipid metabolism plays an imporant role in intralysosomal ceroidogenesis in these histiocytes.     

Diverse functions of the p75 neurotrophin receptor

The pan-neurotrophin receptor p75NTR belongs to a large family of receptors, which includes tumor necrosis factor receptors, Fas and approximately 25 other members. The p75NTR is the first receptor to be cloned molecularly. Recent years have seen the emergence of a consensus regarding the signaling pathways activated by p75NTR and its potential biological function, although receptor characterization had not been targeted for some years. We now know that p75NTR has surprisingly diverse effects, ranging from cell death to regulation of axon elongation. This diversity can be explained by the complex formation of p75NTR with other receptors and multiple signaling molecules that interact with the intracellular domain of p75NTR.     

FAMILIAL AMYLOID POLYNEUROPATHY WITH MARKED HYPERTROPHY OF THE PERIPHERAL NERVES

Autopsy findings in a 40-year-old male with heredofamilial amyloidosis and polyneuropathy are reported. He had been suffering from progressive autonomic as well as sensorimotor dysfunctions. Prominent amyloid deposit was found in the kidney, heart, thyroid, and testis, and less in the interstitium and small vessels of almost all organs. The peripheral nerves, some showing prominent hypertrophy, were most severely involved by amyloid deposit in a form of stellate mass, which ultrastructurally consisted of radially arranged amyloid filaments. In the hypertrophied nerves and ganglia, in addition to amyloid, massive accumulation of acid mucopolysaccharide (AMPS) was seen filling up the interstitial space, which was the cause of hypertrophy. Ultrastructurally, AMPS was seen as finely granular substance. An extracted amyloid from the kidney showed 8 nm filament on negative staining and was estimated of having a molecular weight of 14,000.     

Poly(N-isopropylacrylamide) (PNIPAM)-grafted gelatin hydrogel surfaces: interrelationship between microscopic structure and mechanical property of surface regions and cell adhesiveness

Poly(N-isopropylacrylamide)-grafted gelatin (PNIPAM-gelatin) serves as a temperature-induced scaffold at physiological temperature. This study was aimed at determining the effect of the graft architecture of thermoresponsive PNIPAM-gelatin on the surface topography and elastic modulus of the hydrogels prepared with different architectured PNIPAM-gelatins: the surface topography and elastic modulus were determined by atomic force microscopy (AFM). PNIPAM-gelatin surfaces showed an irregularly concavo-convex structure with a vertical interval of approximately 1 microm regardless of the weight ratio of PNIPAM to gelatin (P/G: 5.8, 12, and 18). The elastic moduli of hydrogels varied at measured sites. The mean elastic moduli of PNIPAM-gelatin with the lowest P/G were low, but increased with increasing P/G. Human umbilical vein endothelial cells adhered and spread on PNIPAM-gelatin hydrogels with the highest P/G, whereas reduced adhesion and nonspreading, round-shaped cells resided on the hydrogels with lower P/Gs. Interrelationship between elastic modulus and cell adhesion and spreading potentials were discussed from physicochemical and cellular biomechanical viewpoints.     

Modifying effects of 1'-acetoxychavicol acetate (ACA) and the novel synthetic retinoids Re-80, Am-580 and Am-55P in a two-stage carcinogenesis model in female rats

Effects of dietary administration of 1'-acetoxychavicol acetate (ACA) and the novel synthetic retinoids 4-[1-hydroxy-3-oxo-3-(5,6,7,8-tetrahydro-3-hydroxy-5,5,8,8-tetramethyl-2-naphthalenyl)-1-propenyl]benzoic acid (Re-80); 4-[(5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-naphthalenyl)carboxamido]benzoic acid (Am-580); and 6-[(3,5-di-tert-butylphenyl) carbamoyl]nicotinic acid (Am-55P) were examined using a two-stage rat carcinogenesis model. A total of 190 female SD rats was treated sequentially with 1,2-dimethylhydrazine (DMH, s.c.); 7,12-dimethylbenz(a)anthracene (DMBA, i.g.); and 2,2'-dihydroxy-di-n-propylnitrosamine (DHPN, in the drinking water) during the first three weeks (DDD-initiation), and an additional 60 rats received the vehicle alone (non-initiation). One week after the completion of the initiation period, they were divided into nine groups and administrated Re-80 (at dose levels of 1.0 or 0.4 ppm), Am-580 (20 or 4 ppm), Am-55P (20 ppm), ACA (100 ppm), all-trans-retinoic acid (10 or 2 ppm) or no supplement in the diet for 33 weeks, until survivors were euthanatized at week 37 weeks. After DDD-initiation, all-trans-retinoic acid at the high dose delayed the development of mammary tumors. The multiplicity of colon tumors in the group fed Am-55P and the incidences of nephroblastomas with ACA or Am-580 were decreased as compared with the control values, but the other chemicals had no modifying effects on tumor development in any organs. Thus, among ACA and the novel synthetic retinoids tested, only Am-55P showed a weak inhibitory effect on a neoplasm of general interest under the present experimental conditions.     

Usefulness of immunoplatelet measurement using the flow cytometric method for accurate platelet counting in hematological patients with severe thrombocytopenia

We measured platelet counts in 95 patients with hematological disorders accompanied by thrombocytopenia (platelet counts < 5.0 x 10(4)/microliter) including 35 patients with severe thrombocytopenia(platelet counts < 2.0 x 10(4)/microliter). We used four methods based on different principles and compared the results, i.e., the flow cytometric method (BEADS method) utilizing platelet-specific monoclonal antibody (SZ2, antiGPIb) in conjunction with fluorescent reference beads (Flow-Count Fluorospheres), manual hemocytometry, and two automated blood cell counters, the NE-8000 (impedance method) and the Technicon H-2 (optical method). The BEADS method was superior to the other methods in linearity of serial dilutions, and the coefficient variations of the BEADS method(2.5-5.2%) were superior to the other methods. The platelet counts measured by the automated blood cell counters were higher(0.6-0.9 x 10(4)/microliter) than those by the BEADS method and manual hemocytometry. Furthermore, the BEADS method was able to measure accurate platelet counts in samples containing red blood cell fragments. The BEADS method may be an accurate and useful method for measuring samples with severe thrombocytopenia, and, especially, samples containing red blood cell fragments.