Retinyl palmitate reduces hepatic fibrosis in rats induced by dimethylnitrosamine or pig serum

BACKGROUND/AIMS

Lipid peroxidation has been found to be associated with Ito cell activation. Ito cells are the principal collagen-producing cells and the main storage sites of retinoids. However, the relationship between retinoids and hepatic fibrosis is complex. The aim of this study was to elucidate the role of retinoids as a fibrosuppressant: the effects of retinoids on hepatic fibrosis induced in rats by dimethylnitrosamine or pig serum, as well as on rat Ito cells in primary culture, were examined in order to assess the antioxidant activity of retinoids.

METHODS

Male Wistar rats were given a single injection of 40 mg/kg dimethylnitrosamine or 0.5 ml PS twice weekly for 10 weeks. In each model, rats were treated with retinyl palmitate for 2 weeks before hepatotoxin treatments or for the last 2 weeks of the treatments. The cumulative amount of retinyl palmitate administered in each experiment was 2, 10, or 20x10(4) IU/rat.

RESULTS

Retinyl palmitate treatment before or after administration of dimethylnitrosamine or pig serum suppressed the induction of hepatic fibrosis, restored hepatic retinyl palmitate levels, prevented increases in hepatic levels of collagen and malondialdehyde, a product of lipid peroxidation, and prevented increases in deposition of type III collagen and the number of alpha-smooth muscle actin (alpha-SMA) positive-Ito cells in the liver. Retinyl palmitate supplementation resulted in a dose-dependent reduction of alpha-SMA expression and an oxidative burst in cultured Ito cells. In addition, retinyl palmitate inhibited Fe2+/adenosine 5'-diphosphate-induced lipid peroxidation in rat liver mitochondria and showed radical scavenging activity.

CONCLUSIONS

These findings suggest that retinyl palmitate may suppress the induction of hepatic fibrosis, at least in part, by the inhibition of Ito cell activation through its antioxidant activity.

Intracellular regulation of macromolecules using pH-sensitive liposomes and nuclear localization signal: qualitative and quantitative evaluation of intracellular trafficking

The objective of this study is to present a rational strategy to target macromolecules to the nucleus via the endocytic pathway. The two major barriers in this route to the nucleus are known as endosomal escape and nuclear transport. pH-sensitive liposomes were used in order to achieve endosomal escape under the conditions of low pH in endosomes. Bovine serum albumin (alb) served as a model compound to be delivered to nucleus and was encapsulated into the pH-sensitive liposomes. The liposomes are composed of dioleoyl phosphatidyl ethanolamine: cholesterylhemisuccinate. They were taken up by rat peritoneal macrophages via endocytosis and subsequently underwent degradation, principally by lysosomal enzymes. By using pH-sensitive liposomes, intracellular degradation was reduced by a significant extent, as expected, via endosomal escape. Cytosolic delivery of FITC-labelled alb was also detected by confocal microscopy. Selective targeting to the nucleus was performed by adding the nuclear localization signal (NLS) of the SV-40 large T antigen to the FITC-alb, which were then encapsulated into the pH-sensitive liposomes. Confocal microscopy revealed that FITC-alb, in the presence of NLS was successfully delivered into nucleus, while no transport was observed in the absence of NLS. These results provide a useful strategy for the nuclear targeting of macromolecules using pH-sensitive liposomes in conjunction with NLS.

Effects of a time-varying strong magnetic field on transient increase in cytosolic free Ca2+ induced by bradykinin in cultured bovine adrenal chromaffin cells

We tested the effects of exposure to a time-varying magnetic field changing between 0.07 and 1.7 T at an interval of 3 s on transient increase in intracellular Ca2+ stimulated by bradykinin in bovine adrenal chromaffin cells. Addition of bradykinin induced the increase in intracellular Ca2+ within a few minutes. The exposure to the magnetic field perfectly suppressed the increase in intracellular Ca2+ in Ca2+-free medium. The inhibition occurred for 15 min when the maximum magnetic flux density was more than 1.4 T. These results suggest that the exposure inhibits Ca2+ release from intracellular Ca2+ stores.

Developmental characteristics in sustained fetal tachycardia in 30 to 41 weeks of gestation

The aim of the present study is to reveal gestational age-related changes in sustained foetal tachycardia (SFT). 24 h fetal heart rate (FHR) recordings were made on 102 normal pregnant women in 30-41 weeks of gestation. SFT was defined as an increase for 20 or more beats per minute from the FHR-baseline persisting for more than 20 min. In the results, SFTs in 38-39 weeks started during night-time (1900-0700) more frequently than during day-time (0700-1900) (P < 0.01, by chi-square test). The rate and duration were 0% and 0 min in 30-31 weeks of gestation, and increased to 85% and 114 min in 40-41 weeks, respectively. Two critical points were detected by a piecewise linear regression analysis: in the rate between 34-35 weeks and 36-37 weeks, and in the duration between 38-39 to 40-41 weeks. We conclude that gestational age-related changes in SFT depend on the developmental stages.

Resistance index of uterine artery and placental location in intrauterine growth retardation

BACKGROUND

Our aim was to investigate the relationship between placental location and resistance index (RI) of uterine arteries in cases with intrauterine growth retardation (IUGR).

METHODS

Placental location and flow velocity waveforms of uterine arteries in 86 normal and 20 IUGR cases from 33 to 38 weeks of gestation were examined using a combined real-time scanner and pulsed Doppler ultrasonography. The location of placenta was classified as lateral when most of it was located to either the right or the left side of the uterine midline. Otherwise it was called central. Cases where the placenta was located in the uterine fundus or in the lower segment were not included. RI values were calculated from the uterine arteries on the placental side, on the non-placental side and in case of central placentas as a mean of both uterine arteries. In normal cases, the calculations were done every second week from 33 to 38 weeks of gestation, and the difference in variance among three gestational ages in each artery was tested by a one-way ANOVA. In IUGR cases, a standard deviation score (SDS) was calculated individually in each artery as (RI - normal mean)/normal SD. Differences in SDS between three categories of uterine arteries were examined by non-parametric tests.

RESULTS

In normal cases, there was no significant difference in variance of RIs among three gestational ages in each category of arteries. In IUGR cases, SDSs on the placental side were higher than those on the non-placental side and those in central placenta, (p<0.01, Wilcoxon's and Mann Whitney's tests, respectively). SDSs in five of eight cases with central placentas were below 1.0. Two of 12 cases with lateral placentas had higher SDSs on the non-placental side than on the placental side and resulted in abruptio placentae.

CONCLUSIONS

Deviation of RIs in uterine arteries with IUGR could be affected by the pathologic conditions of the utero-placental blood flow on the placental side of lateral placenta rather than in central placenta and might be done by dramatic increase in resistance to flow of the myometrial vessels on the non-placental side.

Whole-body vibration and health effects in the agricultural machinery drivers

Recently farm mechanization has been widespread and developing rapidly, in particular riding farm machines are increasingly used in paddy fields in Japan. We have no information available on the actual situation regarding whole-body vibration on the seats of these farm machines from the standpoint of labour protection. Measurement and evaluation of whole-body vibration was performed on the seats of popular riding agricultural machineries. Whole-body vibration on the seats of combine harvesters and wheel tractors exceeded exposure limits and the fatigue-decreased proficiency boundary limit of 8 hr and also shortened the reduced comfort boundary limits of ISO 2631 (1985). Some combines, tractors and carieers had only less than one hour exposure duration as compared with the ISO 2631-1 standard (1997). On the other hand a questionnaire was also performed on the subject of agricultural machine operators. Any specific injury or other effects, i.e. low back injuries were not found among the group of operators as compared with those in non-operator farmers. It seems to be difficult to find out the health effects of whole-body vibration itself, because there may be a lot of causes, i.e. working posture, operating heavy materials, in farm working conditions.

Separate histogenesis of combined hepatocellular and cholangiocellular carcinoma in two patients

Double primary liver carcinomas, i.e. hepatocellular carcinoma (HCC) and cholangiocellular carcinoma (CCC) are rare. Two patients in whom double primary liver carcinomas were surgically resected are described herein. Case 1: A 51-year-old Japanese man with chronic type B hepatitis underwent hepatectomy for primary HCC with intrahepatic metastasis. Case 2: A 67-year-old Japanese man with a history of rectal cancer and CCC underwent lateral hepatic segmentectomy for a suspected recurrence of intrahepatic CCC. Lack of direct contact between tumors, no evidence of histological transition and clearly different immunohistochemical staining for cytokeratin support a distinct histogenesis of the tumors in these two patients. The findings indicate that combined HCC and CCC can arise synchronously or metachronously as an intrahepatic double cancer.

Effects of nitroprusside and nicorandil on catecholamine secretion and calcium mobilization in cultured bovine adrenal chromaffin cells

The effects of nitroprusside and nicorandil on catecholamine secretion and free intracellular Ca2+ ([Ca2+]i) mobilization in bovine adrenal chromaffin cells were studied to evaluate the role of the nitric oxide (NO)/cyclic guanosine monophosphate (cGMP) pathway in the regulation of a [Ca2+]i-dependent secretory process. These effects were compared with those of nifedipine, a typical voltage-dependent Ca2+ channel blocker. Carbachol produced a rapid increase followed by a sustained increase of [Ca2+]i (Ca2+ transient) in cultured bovine adrenal chromaffin cells. Both nitroprusside and nicorandil accelerated the decrease in [Ca2+]i without changing the peak values of the initial [Ca2+]i increase of Ca2+ transient. These drugs, however, did not affect carbachol-induced catecholamine secretion, suggesting that secretion is related to the initial [Ca2+]i increase and not to a late sustained [Ca2+]i increases. However, nifedipine reduced the peak and duration of carbachol-induced [Ca2+]i increases and decreased the secretion of catecholamines. Diethylamine/NO complex, an NO donor, and dibutyryl-cGMP produced similar changes in Ca2+ transient and did not alter catecholamine secretion, suggesting that the effects of nitroprusside and nicorandil were mediated by the NO/cGMP pathway. These results indicated that the pattern of Ca2+ transient, especially the initial increase in [Ca2+]i, is important in secretion of catecholamine.

The effect of behavioral states on fetal heart rate and middle cerebral artery flow-velocity waveforms in normal full-term fetuses

OBJECTIVES

To evaluate the effect of fetal behavioral states on the relationship between fetal heart rate (FHR) and middle cerebral artery resistance index (MCA RI) in normal fetuses.

METHODS

The FHR and MCA RI of 10 normal cases from 37 to 40 weeks of gestation were recorded consecutively over a 45-min period. Correlations between the MCA RI and FHR during resting and active phases, classified by an actocardiotocogram, were analyzed by simple regression analysis.

RESULTS

The mean FHR and MCA RI were significantly higher during the active phase (140.3 +/- 6.6 bpm, 0.79 +/- 0.06) than those during the resting phase (137.4 +/- 6.8 bpm, 0.75 +/- 0.07, P < 0.01, two sample t-test). There was a significant negative correlation (r = - 0.22, n = 2642, P < 0.01) between RI and FHR during the active phase and a significant positive correlation (r = 0.28, n = 2066, P < 0.001) during the resting phase.

CONCLUSIONS

The relationship between FHR and the MCA RI during the resting phase is different from during the active phase.

Apolipoprotein E epsilon2 allele and early onset schizophrenia

To explore the role of apolipoprotein E (ApoE) in schizophrenia, we investigated ApoE phenotypes in a group of patients with schizophrenia. Serum samples were obtained from 122 schizophrenic patients and 126 controls in Japan and were examined using isoelectric focusing/immunoblotting. This experiment showed a trend toward a decreased frequency of ApoE epsilon4 in schizophrenia and no link between ApoE epsilon4 and familial schizophrenia or early onset schizophrenia. On the other hand, a decreased frequency of ApoE epsilon2 in early onset schizophrenia was detected. These results suggest that ApoE epsilon2 protects against early onset schizophrenia, and that ApoE epsilon4 is not involved in the development of schizophrenia in Japanese.

Risk estimation for hypertension based on follow-up health examination data in a small village in Kumamoto prefecture, Japan

The estimation of risk for incidence of hypertension was carried out by follow-up study in a small village in Kumamoto Prefecture, Japan (N=750, 48.2±15.2months). The most significant risk in both sexes was blood pressure at entry. As for other risks, age, total cholesterol, and BMI in females were significant risks for systolic and diastolic blood pressure changes to greater than the borderline level. These factors in males were not significant. From the results of analysis using Cox's proportional hazards model, drinking in males was shown to be a significant risk for diastolic change, and in females for systolic change. It was concluded that excessive drinking in both sexes and obesity in females led to important health problems associated with hypertension among the subjects of the study.

Preferential subsarcolemmal localization of dystrophin and beta-dystroglycan mRNA in human skeletal muscles

The intracellular localization of dystrophin and beta-dystroglycan mRNA in skeletal muscles of patients with Duchenne muscular dystrophy (DMD) or Becker muscular dystrophy (BMD) and normal subjects was examined by in situ hybridization using biotinylated oligonucleotide probes. These mRNAs were found preferentially in sarcolemma in the skeletal muscles of both normal subjects and affected patients. Quantitative analysis of mRNA signals demonstrated no prominent reduction of dystrophin or beta-dystroglycan mRNA in DMD/BMD muscles. These results suggest that even mRNAs with deletions contain specific information that affects their localization, and the characteristic defect of dystrophin in DMD/BMD muscles seems to be caused mainly by the instability of dystrophin protein, as a post-transcriptional event.

Vitamin D3 elicits calcium response and activates blood monocyte-derived macrophages from patients with vitamin D dependent rickets type II

We studied the effects of vitamin D3 metabolites on intracellular free Ca2+ concentration ([Ca2+]i) and the respiratory burst of monocyte-derived macrophages (MDM) from patients with vitamin D dependent rickets type II. Treatment of MDM from the patients and healthy donors with 1 nM 1,25(OH)2D3 produced a rapid elevation of [Ca2+]i and similarly primed both types of cells for enhanced capacity for O2- release with phorbol diester. These results suggest that macrophages may have distinct non-genomic pathways of vitamin D3, which partly explain the absence of immunodeficiency and the disappearance of rickets after treatment with vitamin D3 in the patients.

Characteristics of calcium ion influx induced by human follicular fluid in individual human sperm

The mechanism of Ca2+ influx into human spermatozoa was investigated. Human follicular fluid (hFF), which contains progesterone, stimulated an increase in the concentration of intracellular free Ca2+ ([Ca2+]i) as measured by fluorescence spectroscopy using Fura-2/AM. The technique allowed the measurement of [Ca2+]i in individual, motile spermatozoa, by improvement of the previous methods. The role of Ca2+ channels was investigated using selective blocking agents. Neither blockade of L-type channels with verapamil or lanthanum (La3+) nor blockade of N-type channels with omega-conotoxin affected the hFF-stimulated increase in [Ca2+]i. Blockade of T-type channels with either nickel (Ni2+) or amiloride significantly reduced the hFF-stimulated increase in [Ca2+]i and amiloride significantly decreased baseline [Ca2+]i. Incubation of sperm in Na(+)-free medium did not affect [Ca2+]i, indicating that Na+/Ca2+ exchange has no major role in Ca2+ influx. The results suggest that calcium influx induced by hFF occurs via T-type voltage-independent Ca2+ channels. The method described allows accurate measurement of [Ca2+]i in individual, motile human spermatozoa.

Radical forearm flap with vascularized tendons for hand reconstruction

We treated six patients with soft-tissue defects involving the skin and extensor or flexor tendons using a cutaneotendinous radial forearm flap. There were five male patients and one female patient. Their ages at operation ranged from 22 to 65 years (mean 50 years). In one patient, the flexor pollicis longus tendon was reconstructed with a palmaris longus tendon graft. Four patients each had two extensor tendons reconstructed. This was performed either with the palmaris longus tendon folded in the center (n = 2) or with the palmaris longus and flexor carpi radialis tendons (n = 2). In the remaining patient, three extensor tendons were reconstructed with the palmaris longus and flexor carpi radialis tendons. All the flaps survived. Recovery of motor function has been satisfactory in all but one patient.

Insulin potentiates mitogenic effect of epidermal growth factor on cultured guinea pig gastric mucous cells

Epidermal growth factor (EGF) stimulated proliferation of gastric mucous epithelial cells from guinea pigs in serum-free culture conditions. Western blot analysis with antiphosphotyrosine antibody showed that EGF initiated tyrosine phosphorylation of a 170-kDa protein, and this protein was identical to the EGF receptor. Insulin was not mitogenic, but it potentiated the mitogenic effect of EGF. Tyrosine phosphorylation of additional proteins was not induced by the combined actions of insulin and EGF. Stimulation by EGF and/or insulin did not cause a calcium response. However, when insulin was added to cells pretreated with EGF for > 6 h, it elicited a rapid intracellular calcium concentration rise that was reproducible in both cell suspension and single cell analyses. This calcium response coincided with the translocation of protein kinase C (PKC) from the cytosolic to the particulate fraction. Phorbol 12-myristate 13-acetate also caused the translocation and stimulated proliferation of the cells. These results suggest that the calcium-dependent activation of PKC may participate in the potentiation of the mitogenic effect of EGF by insulin.

Localization and amount of myoglobin and myoglobin mRNA in ragged-red fiber of patients with mitochondrial encephalomyopathy

The localization and amounts of myoglobin (Mb) and Mb mRNA in ragged-red fibers (RRF) in skeletal muscle of 6 patients with mitochondrial encephalomyopathy were examined immunohistochemically and by in situ hybridization. The amounts of Mb and Mb mRNA were expressed in terms of optical densities (ODs) of Mb immunostaining and Mb mRNA signals. In nonatrophic RRF, Mb was predominantly seen in the ragged-red region and Mb mRNA signals were increased throughout the sarcoplasm. The amounts of Mb and Mb mRNA in nonatrophic RRF were greater than those in nonatrophic non-RRF. In contrast, the localization and amount in atrophic RRF were similar to those in atrophic non-RRF. Thus, Mb synthesis in nonatrophic RRF may increase to compensate for mitochondrial dysfunction and to supply sufficient oxygen to mitochondria, but this compensatory function may be impaired in atrophic RRF.

Adrenomedullin stimulates calcium efflux from adrenal chromaffin cells in culture: possible involvement of an Na+/Ca2+ exchange mechanism

The effect of adrenomedullin, a hypotensive peptide, on Ca2+ efflux from cultured bovine adrenal chromaffin cells was examined. Adrenomedullin stimulated the efflux of 45Ca2+ from the cells in a concentration-dependent manner (10(-7)M - 3x10(-6)M). Adrenomedullin did not increase the intracellular free Ca2+ ([Ca2+]i) level and catecholamine secretion. The adrenomedullin-stimulated 45Ca2+ efflux was not inhibited by incubation with Ca2+-free medium, but was inhibited by incubation with Na+-free medium. These results indicate that adrenomedullin stimulates extracellular Na+-dependent 45Ca2+ efflux from cultured bovine adrenal chromaffin cells, probably through its stimulatory effect on membrane Na+/Ca2+ exchange.

One of the rubber latex allergens is a lysozyme

BACKGROUND

Type I hypersensitivity reactions caused by latex products are ascribed to proteins eluted from them, but little is known about the properties of these allergenic proteins. The reason for the cross-reaction between rubber latex and fruits is also not known. We have speculated that a series of defense-related proteins in plants is a cause of latex allergy and the cross reaction.

OBJECTIVE

To verify our hypothesis, we selected a lysozyme as a representative defense-related protein and examined its relationship to latex allergy.

METHODS

Lysozymes eluted from latex gloves were detected with a cell-suspension clearing test. A chromatographically separated lysozyme was investigated for its physicochemical and enzymatic properties and allergenicity.

RESULTS

Lysozyme activity was detected in extracts from ammoniated latex and latex gloves. We separated a lysozyme (27 kd; isoelectric point, 9.5) using cation-exchange and gel filtration chromatography. This lysozyme was enzymatically very similar to fruit lysozymes and was demonstrated to be an allergen.

CONCLUSIONS

One of the rubber latex allergens is a lysozyme that has similarities to fruit lysozymes. This suggests the relevance of defense-related proteins to latex allergy and the cross reaction.

Regulations by cyclic nucleotides and phorbol ester of calcium efflux from cultured bovine adrenal chromaffin cells

The effects of cyclic nucleotides and phorbol ester on Ca2+ efflux from cultured bovine adrenal chromaffin cells were examined. Dibutyryl cyclic AMP (DB-cAMP), forskolin (an activator of adenylate cyclase), dibutyryl cyclic GMP (DB-cGMP) and nitroprusside (an activator of guanylate cyclase) all stimulated 45Ca2+ efflux from the cells preloaded with 45Ca2+. These agents did not increase the intracellular free Ca2+ ([Ca2+]i) level. On the contrary, phorbol 12-myristate 13-acetate (PMA; an activator of protein kinase C) did not affect the efflux of 45Ca2+, but inhibited the increase in 45Ca2+ efflux caused by DB-cAMP, forskolin, DB-cGMP or nitroprusside. The 45Ca2+ effluxes stimulated by cyclic nucleotides, forskolin and nitroprusside were inhibited by deprivation of extracellular Na+ ([Na+]o). These results suggest that both cAMP- and cGMP-dependent protein kinases are involved in the stimulatory mechanism of [Na+]o dependent Ca2+ efflux, probably through acceleration of [Na+]o/[Ca2+]i exchange and that protein kinase C plays an inhibitory role in this mechanism.

Partial Purification of a Na+ -ATPase from the Plasma Membrane of the Marine Alga Heterosigma akashiwo

A Na+ -ATPase was partially purified from plasma membranes of the marine alga Heterosigma akashiwo. The plasma membranes of H. akashiwo cells were collected by differential centrifugation with subsequent discontinuous gradient centrifugation. Na+ -ATPase activity was associated with the resultant plasma membrane fraction and was stimulated to the greatest extent in the presence of 100 to 200 mM Na+, 10 mM K+, and 5 mM Mg2+ ions, pH 8.0. The Km value for Na+ ions was 12.2 mM. An apparent Km value for ATP was 880 [mu]M. A 140-kD phosphorylated intermediate was also detected in the same fraction in the presence of both Mg2+ and Na+ ions, and this protein was dephosphorylated upon the addition of K+ ions. We could partially purify the 140-kD protein after solubilization by Suc monolaurate and fractionation by sequential column chromatography on Sephacryl S-300, DEAE-Sepharose CL-6B, and Mono-Q columns. The purified 140-kD polypeptide could also be phosphorylated and be detected after acid sodium dodecyl sulfate-polyacryl-amide gel electrophoresis in the presence of Na+ and Mg2+ ions.

Kinetic analysis of endocytosis and intracellular fate of liposomes in single macrophages

Endocytosis and the intracellular fate of liposomes in single mouse peritoneal macrophages were examined kinetically by fluorescence microphotometry. Liposomes labeled with N-(7-nitro-2,1,3-benzoxadiazol-4-yl)phosphatidylethanolamine or containing 8-amino-naphthalene-1,3,6-trisulfonate were promptly incorporated into macrophages on incubation at 37 degrees C, but fluorescence increase caused by hydrolysis of 4-methylumbelliferyl-beta-D-glucoside encapsulated in the liposomes was observed after 30 min of incubation. The fluorescences of calcein and 8-hydroxy-1,3,6-pyrenetrisulfonate (HPTS) in liposomes, which were respectively quenched statically due to high concentration and dynamically by a co-entrapped fluorescence quencher, p-xylene-bis-pyridinium bromide, also increased from 30 min after the start of liposome incorporation, indicating that macrophages require this period for intracellular delivery of liposomes from the cell surface to lysosomes. Measurement of the intraendosomal pH change in a single macrophage at 37 degrees C with liposomes containing a pH-sensitive fluorescent marker, HPTS, showed that the pH value decreased continuously to a constant value of 5.5 in 30-40 min after endocytosis, and this decrease was reversed on addition of NH4Cl, suggesting that acidification of endosomes is not a stepwise reaction and is coupled with delivery of liposomes. These fluorescence microphotometric systems using liposomes containing different fluorescent dyes should be useful for kinetic analyses of the endocytosis and intracellular fate of liposomes in various phagocytes.