Impact of the COVID-19 pandemic on the incidence of surgical site infection after orthopaedic surgery: an interrupted time series analysis of the nationwide surveillance database in Japan

BACKGROUND

During the COVID-19 pandemic, hygiene awareness was increased in communities and hospitals. However, there is controversy regarding whether such circumstances affected the incidence of surgical site infections (SSIs) in the orthopaedic surgical field.

AIM

To examine the impact of the COVID-19 pandemic on the incidence of SSIs after orthopaedic surgery.

METHODS

The medical records of patients having undergone orthopaedic surgery were extracted from the nationwide surveillance database in Japan. The primary outcomes were the monthly incidences of total SSIs, deep or organ/space SSIs, and SSIs due to meticillin-resistant Staphylococcus aureus (MRSA). Interrupted time series analysis was conducted between pre-pandemic (January 2017 to March 2020) and pandemic (April 2020 to June 2021) periods.

RESULTS

A total of 309,341 operations were included. Interrupted time series analysis adjusted for seasonality showed no significant changes in the incidence of total SSIs (rate ratio 0.94 and 95% confidence interval 0.98-1.02), deep or organ/space SSIs (0.91, 0.72-1.15), or SSIs due to MRSA (1.07, 0.68-1.68) along with no remarkable slope changes in any parameter (1.00, 0.98-1.02; 1.00, 0.97-1.02; and 0.98, 0.93-1.03, respectively).

CONCLUSIONS

Awareness and measures against the COVID-19 pandemic did not markedly influence the incidence of total SSIs, deep or organ/space SSIs, or SSIs due to MRSA following orthopaedic surgery in Japan.

Lysosomal cholesterol overload in macrophages promotes liver fibrosis in a mouse model of NASH

Accumulation of lipotoxic lipids, such as free cholesterol, induces hepatocyte death and subsequent inflammation and fibrosis in the pathogenesis of nonalcoholic steatohepatitis (NASH). However, the underlying mechanisms remain unclear. We have previously reported that hepatocyte death locally induces phenotypic changes in the macrophages surrounding the corpse and remnant lipids, thereby promoting liver fibrosis in a murine model of NASH. Here, we demonstrated that lysosomal cholesterol overload triggers lysosomal dysfunction and profibrotic activation of macrophages during the development of NASH. β-cyclodextrin polyrotaxane (βCD-PRX), a unique supramolecule, is designed to elicit free cholesterol from lysosomes. Treatment with βCD-PRX ameliorated cholesterol accumulation and profibrotic activation of macrophages surrounding dead hepatocytes with cholesterol crystals, thereby suppressing liver fibrosis in a NASH model, without affecting the hepatic cholesterol levels. In vitro experiments revealed that cholesterol-induced lysosomal stress triggered profibrotic activation in macrophages predisposed to the steatotic microenvironment. This study provides evidence that dysregulated cholesterol metabolism in macrophages would be a novel mechanism of NASH.

Nanosecond Random Telegraph Noise in In-Plane Magnetic Tunnel Junctions

We study the timescale of random telegraph noise (RTN) of nanomagnets in stochastic magnetic tunnel junctions (MTJs). From analytical and numerical calculations based on the Landau-Lifshitz-Gilbert and the Fokker-Planck equations, we reveal mechanisms governing the relaxation time of perpendicular easy-axis MTJs (p-MTJs) and in-plane easy-axis MTJs (i-MTJs), showing that i-MTJs can be made to have faster RTN. Superparamagnetic i-MTJs with small in-plane anisotropy and sizable perpendicular effective anisotropy show relaxation times down to 8 ns at negligible bias current, which is more than 5 orders of magnitude shorter than that of typical stochastic p-MTJs and about 100 times faster than the shortest time of i-MTJs reported so far. The findings give a new insight and foundation in developing stochastic MTJs for high-performance probabilistic computers.

Peptide precursors that acquire denatured collagen-hybridizing ability by O-to-N acyl migration at physiological pH

Here, we report peptide probes with either single or cyclic double stranded collagen-like sequences that spontaneously acquire collagen-hybridizing ability at physiological pH. These peptides have ester bonds derived from O-acyl isopeptide units that are converted to amide bonds via intramolecular O-to-N acyl migration by a pH shift. The peptides that do not require pre-treatment for disassembly will be useful as prodrugs in theranostic treatments targeting unfolded collagen.

Dipeptidyl peptidase-4 inhibition prevents nonalcoholic steatohepatitis-associated liver fibrosis and tumor development in mice independently of its anti-diabetic effects

Nonalcoholic steatohepatitis (NASH) is a hepatic phenotype of the metabolic syndrome, and increases the risk of cirrhosis and hepatocellular carcinoma (HCC). Although increasing evidence points to the therapeutic implications of certain types of anti-diabetic agents in NASH, it remains to be elucidated whether their effects on NASH are independent of their effects on diabetes. Genetically obese melanocortin 4 receptor–deficient (MC4R-KO) mice fed Western diet are a murine model that sequentially develops hepatic steatosis, NASH, and HCC in the presence of obesity and insulin resistance. In this study, we investigated the effect of the dipeptidyl peptidase-4 (DPP-4) inhibitor anagliptin on NASH and HCC development in MC4R-KO mice. Anagliptin treatment effectively prevented inflammation, fibrosis, and carcinogenesis in the liver of MC4R-KO mice. Interestingly, anagliptin only marginally affected body weight, systemic glucose and lipid metabolism, and hepatic steatosis. Histological data and gene expression analysis suggest that anagliptin treatment targets macrophage activation in the liver during the progression from simple steatosis to NASH. As a molecular mechanism underlying anagliptin action, we showed that glucagon-like peptide-1 suppressed proinflammatory and profibrotic phenotypes of macrophages in vitro. This study highlights the glucose metabolism–independent effects of anagliptin on NASH and HCC development.

Upregulation of cancer-associated gene expression in activated fibroblasts in a mouse model of non-alcoholic steatohepatitis

Non-alcoholic steatohepatitis (NASH), characterized by chronic inflammation and fibrosis, is predicted to be the leading cause of cirrhosis and hepatocellular carcinoma (HCC) in the next decade. Although recent evidence suggests the importance of fibrosis as the strongest determinant of HCC development, the molecular mechanisms underlying NASH-induced carcinogenesis still remain unclear. Here we performed RNA sequencing analysis to compare gene expression profiles of activated fibroblasts prepared from two distinct liver fibrosis models: carbon tetrachloride–induced fibrosis as a model without obesity and HCC and genetically obese melanocortin 4 receptor–deficient (MC4R-KO) mice fed Western diet, which develop steatosis, NASH, and eventually HCC. Our data showed that activated fibroblasts exhibited distinct gene expression patterns in each etiology, and that the ‘pathways in cancer’ were selectively upregulated in the activated fibroblasts from MC4R-KO mice. The most upregulated gene in these pathways was fibroblast growth factor 9 (FGF9), which was induced by metabolic stress such as palmitate. FGF9 exerted anti-apoptotic and pro-migratory effects in fibroblasts and hepatoma cells in vitro and accelerated tumor growth in a subcutaneous xenograft model. This study reveals upregulation of cancer-associated gene expression in activated fibroblasts in NASH, which would contribute to the progression from NASH to HCC.

Obeticholic acid protects against hepatocyte death and liver fibrosis in a murine model of nonalcoholic steatohepatitis

Accumulating evidence has suggested that farnesoid X receptor (FXR) agonists, such as obeticholic acid (OCA) are therapeutically useful for non-alcoholic steatohepatitis (NASH). However, it is still unclear how FXR agonists protect against NASH and which cell type is the main target of FXR agonists. In this study, we examined the effects of OCA on the development of NASH using melanocortin 4 receptor-deficient (MC4R-KO) mice that progressively developed hepatic steatosis and NASH on Western diet (WD). Treatment with OCA effectively prevented chronic inflammation and liver fibrosis in WD-fed MC4R-KO mice with only marginal effect on body weight and hepatic steatosis. Hepatic crown-like structure (hCLS) is a unique histological structure characteristic of NASH, which triggers hepatocyte death-induced interstitial fibrosis. Intriguingly, treatment with OCA markedly reduced hCLS formation even after MC4R-KO mice developed NASH, thereby inhibiting the progression of liver fibrosis. As its mechanism of action, OCA suppressed metabolic stress-induced p53 activation and cell death in hepatocytes. Our findings in this study highlight the role of FXR in hepatocytes in the pathogenesis of NASH. Collectively, this study demonstrates the anti-fibrotic effect of OCA in a murine model of NASH with obesity and insulin resistance, which suggests the clinical implication for human NASH.

CD11c+ resident macrophages drive hepatocyte death-triggered liver fibrosis in a murine model of nonalcoholic steatohepatitis

Although recent evidence has pointed to the role of organ- and pathogenesis-specific macrophage subsets, it is still unclear which subsets are critically involved in the pathogenesis of nonalcoholic steatohepatitis (NASH). Using melanocortin-4 receptor-deficient (MC4R-KO) mice fed Western diet (WD), which exhibit liver phenotypes similar to those of human NASH, we found a histological structure, termed hepatic crown-like structure (hCLS), in which CD11c+ macrophages surround dead/dying hepatocytes, a prominent feature of NASH. Here, we demonstrate that hCLS-constituting macrophages could be a novel macrophage subset that drives hepatocyte death-triggered liver fibrosis. In an "inducible NASH model," hepatocyte death induces hCLS formation and liver fibrosis sequentially in the short term. In combination with the long-term WD feeding model, we also showed that resident macrophages are a major cellular source of CD11c+ macrophages constituting hCLS, which exhibited gene expression profiles distinct from CD11c- macrophages scattered in the liver. Moreover, depletion of CD11c+ macrophages abolished hCLS formation and fibrogenesis in NASH. Our clinical data suggest the role of CD11c+ macrophages in the disease progression from simple steatosis to NASH. This study sheds light on the role of resident macrophages, in addition to recruited macrophages, in the pathogenesis of NASH.

Identification of novel BCL11A variants in patients with epileptic encephalopathy: Expanding the phenotypic spectrum

BCL11A encodes a zinc finger protein that is highly expressed in hematopoietic tissues and the brain, and that is known to function as a transcriptional repressor of fetal hemoglobin (HbF). Recently, de novo variants in BCL11A have been reported in individuals with intellectual disability syndrome without epilepsy. In this study, we performed whole-exome sequencing of 302 patients with epileptic encephalopathies (EEs), and identified 2 novel BCL11A variants, c.577delC (p.His193Metfs*3) and c.2351A>C (p.Lys784Thr). Both the patients shared major physical features characteristic of BCL11A-related intellectual disability syndrome, suggesting that characteristic physical features and the persistence of HbF should lead clinicians to suspect EEs caused by BCL11A pathogenic variants. Patient 1, with a frameshift variant, presented with Lennox-Gastaut syndrome, which expands the phenotypic spectrum of BCL11A haploinsufficiency. Patient 2, with a p.Lys784Thr variant, presented with West syndrome followed by drug-resistant focal seizures and more severe developmental disability. These 2 newly described patients contribute to delineating the associated, yet uncertain phenotypic characteristics of BCL11A disease-causing variants.

Ligand-activated PPARα-dependent DNA demethylation regulates the fatty acid β-oxidation genes in the postnatal liver

The metabolic function of the liver changes sequentially during early life in mammals to adapt to the marked changes in nutritional environment. Accordingly, hepatic fatty acid β-oxidation is activated after birth to produce energy from breast milk lipids. However, how it is induced during the neonatal period is poorly understood. Here we show DNA demethylation and increased mRNA expression of the fatty acid β-oxidation genes in the postnatal mouse liver. The DNA demethylation does not occur in the fetal mouse liver under the physiologic condition, suggesting that it is specific to the neonatal period. Analysis of mice deficient in the nuclear receptor peroxisome proliferator-activated receptor α (PPARα) and maternal administration of a PPARα ligand during the gestation and lactation periods reveal that the DNA demethylation is PPARα dependent. We also find that DNA methylation of the fatty acid β-oxidation genes are reduced in the adult human liver relative to the fetal liver. This study represents the first demonstration that the ligand-activated PPARα-dependent DNA demethylation regulates the hepatic fatty acid β-oxidation genes during the neonatal period, thereby highlighting the role of a lipid-sensing nuclear receptor in the gene- and life-stage-specific DNA demethylation of a particular metabolic pathway.

Comparative proteomic profiling reveals aberrant cell proliferation in the brain of embryonic Ts1Cje, a mouse model of Down syndrome

To identify molecular candidates involved in brain disabilities of Ts1Cje, a mouse model of Down syndrome (DS), we performed comparative proteomic analyses. Proteins extracted from the brains of postnatal wild-type (WT) and Ts1Cje mice were analyzed by two-dimensional gel electrophoresis (2-DE). No differences were detected in the proteins expressed in the whole brain between WT and Ts1Cje mice at postnatal day 0 and 3months of age. Five spots with differential expression in the brains of Ts1Cje mice were detected by 2-DE of brain proteins from WT and Ts1Cje embryos at embryonic day 14.5 (E14.5). These differentially expressed proteins in Ts1Cje embryos were identified as calcyclin-binding protein (CACYBP), nucleoside diphosphate kinase-B (NDPK-B), transketolase (TK), pyruvate kinase (PK), and 60S acidic ribosomal protein P0 (RPLP0) by peptide mass fingerprinting. CACYBP and NDPK-B were involved in cell proliferation, whereas TK and PK were associated with energy metabolism. Experiments on cell proliferation, an in vivo bromodeoxyuridine (BrdU)-labeling experiment, and immunohistochemical analysis for phospho-histone H3 (an M-phase marker) demonstrated increased numbers of BrdU-positive and M-phase cells in the ganglionic eminence. Our findings suggest that the dysregulated expression of proteins demonstrated by comparative proteomic analysis could be a factor in increased cell proliferation, which may be associated with abnormalities in DS brain during embryonic life.

FOXO1 activates glutamine synthetase gene in mouse skeletal muscles through a region downstream of 3'-UTR: possible contribution to ammonia detoxification

Skeletal muscle is a reservoir of energy in the form of protein, which is degraded under catabolic conditions, resulting in the formation of amino acids and ammonia as a byproduct. The expression of FOXO1, a forkhead-type transcription factor, increases during starvation and exercise. In agreement, transgenic FOXO1-Tg mice that overexpress FOXO1 in skeletal muscle exhibit muscle atrophy. The aim of this study was to examine the role of FOXO1 in amino acid metabolism. The mRNA and protein expressions of glutamine synthetase (GS) were increased in skeletal muscle of FOXO1-Tg mice. Fasting induced FOXO1 and GS expression in wild-type mice but hardly increased GS expression in muscle-specific FOXO1 knockout (FOXO1-KO) mice. Activation of FOXO1 also increased GS mRNA and protein expression in C2C12 myoblasts. Using a transient transfection reporter assay, we observed that FOXO1 activated the GS reporter construct. Mutation of a putative FOXO1-binding consensus sequence in the downstream genomic region of GS decreased basal and FOXO1-dependent reporter activity significantly. A chromatin immunoprecipitation assay showed that FOXO1 was recruited to the 3' region of GS in C2C12 myoblasts. These results suggest that FOXO1 directly upregulates GS expression. GS is considered to mediate ammonia clearance in skeletal muscle. In agreement, an intravenous ammonia challenge increased blood ammonia concentrations to a twofold higher level in FOXO1-KO than in wild-type mice, demonstrating that the capacity for ammonia disposal correlated inversely with the expression of GS in muscle. These data indicate that FOXO1 plays a role in amino acid metabolism during protein degradation in skeletal muscle.

Role of DNA methylation in the regulation of lipogenic glycerol-3-phosphate acyltransferase 1 gene expression in the mouse neonatal liver

The liver is a major organ of lipid metabolism, which is markedly changed in response to physiological nutritional demand; however, the regulation of hepatic lipogenic gene expression in early life is largely unknown. In this study, we show that expression of glycerol-3-phosphate acyltransferase 1 (GPAT1; Gpam), a rate-limiting enzyme of triglyceride biosynthesis, is regulated in the mouse liver by DNA methylation, an epigenetic modification involved in the regulation of a diverse range of biological processes in mammals. In the neonatal liver, DNA methylation of the Gpam promoter, which is likely to be induced by Dnmt3b, inhibited recruitment of the lipogenic transcription factor sterol regulatory element-binding protein-1c (SREBP-1c), whereas in the adult, decreased DNA methylation resulted in active chromatin conformation, allowing recruitment of SREBP-1c. Maternal overnutrition causes decreased Gpam promoter methylation with increased GPAT1 expression and triglyceride content in the pup liver, suggesting that environmental factors such as nutritional conditions can affect DNA methylation in the liver. This study is the first detailed analysis of the DNA-methylation-dependent regulation of the triglyceride biosynthesis gene Gpam, thereby providing new insight into the molecular mechanism underlying the epigenetic regulation of metabolic genes and thus metabolic diseases.

Increased systemic glucose tolerance with increased muscle glucose uptake in transgenic mice overexpressing RXRγ in skeletal muscle

Background

Retinoid X receptor (RXR) γ is a nuclear receptor-type transcription factor expressed mostly in skeletal muscle, and regulated by nutritional conditions. Previously, we established transgenic mice overexpressing RXRγ in skeletal muscle (RXRγ mice), which showed lower blood glucose than the control mice. Here we investigated their glucose metabolism.

Methodology/Principal Findings

RXRγ mice were subjected to glucose and insulin tolerance tests, and glucose transporter expression levels, hyperinsulinemic-euglycemic clamp and glucose uptake were analyzed. Microarray and bioinformatics analyses were done. The glucose tolerance test revealed higher glucose disposal in RXRγ mice than in control mice, but insulin tolerance test revealed no difference in the insulin-induced hypoglycemic response. In the hyperinsulinemic-euglycemic clamp study, the basal glucose disposal rate was higher in RXRγ mice than in control mice, indicating an insulin-independent increase in glucose uptake. There was no difference in the rate of glucose infusion needed to maintain euglycemia (glucose infusion rate) between the RXRγ and control mice, which is consistent with the result of the insulin tolerance test. Skeletal muscle from RXRγ mice showed increased Glut1 expression, with increased glucose uptake, in an insulin-independent manner. Moreover, we performed in vivo luciferase reporter analysis using Glut1 promoter (Glut1-Luc). Combination of RXRγ and PPARδ resulted in an increase in Glut1-Luc activity in skeletal muscle in vivo. Microarray data showed that RXRγ overexpression increased a diverse set of genes, including glucose metabolism genes, whose promoter contained putative PPAR-binding motifs.

Conclusions/Significance

Systemic glucose metabolism was increased in transgenic mice overexpressing RXRγ. The enhanced glucose tolerance in RXRγ mice may be mediated at least in part by increased Glut1 in skeletal muscle. These results show the importance of skeletal muscle gene regulation in systemic glucose metabolism. Increasing RXRγ expression may be a novel therapeutic strategy against type 2 diabetes.

A perpendicular-anisotropy CoFeB-MgO magnetic tunnel junction

Magnetic tunnel junctions (MTJs) with ferromagnetic electrodes possessing a perpendicular magnetic easy axis are of great interest as they have a potential for realizing next-generation high-density non-volatile memory and logic chips with high thermal stability and low critical current for current-induced magnetization switching. To attain perpendicular anisotropy, a number of material systems have been explored as electrodes, which include rare-earth/transition-metal alloys, L1(0)-ordered (Co, Fe)-Pt alloys and Co/(Pd, Pt) multilayers. However, none of them so far satisfy high thermal stability at reduced dimension, low-current current-induced magnetization switching and high tunnel magnetoresistance ratio all at the same time. Here, we use interfacial perpendicular anisotropy between the ferromagnetic electrodes and the tunnel barrier of the MTJ by employing the material combination of CoFeB-MgO, a system widely adopted to produce a giant tunnel magnetoresistance ratio in MTJs with in-plane anisotropy. This approach requires no material other than those used in conventional in-plane-anisotropy MTJs. The perpendicular MTJs consisting of Ta/CoFeB/MgO/CoFeB/Ta show a high tunnel magnetoresistance ratio, over 120%, high thermal stability at dimension as low as 40 nm diameter and a low switching current of 49 microA.

Increased expression of DNA methyltransferase 3a in obese adipose tissue: studies with transgenic mice

Epigenetic mechanisms are likely to be involved in the development of obesity. This study was designed to examine the role of a DNA methyltransferase (Dnmt3a), in obese adipose tissue. The gene expression of Dnmts was examined by quantitative real-time PCR analysis. Transgenic mice overexpressing Dnmt3a in the adipose tissue driven by the aP2 promoter were created (Dnmt3a mice). DNA methylation of downregulated genes was examined using bisulfite DNA methylation analysis. Dnmt3a mice were fed a methyl-supplemented or high-fat diet, and subjected to body weight measurement and gene expression analysis of the adipose tissue. Expression of Dnmt3a was markedly upregulated in the adipose tissue of obese mice. The complementary DNA (cDNA) microarray analysis of Dnmt3a mice revealed a slight decrease in the gene expression of secreted frizzled-related protein 1 (SFRP1) and marked increase in that of interferon responsive factor 9 (IRF9). In the SFRP1 promoter, DNA methylation was not markedly increased in Dnmt3a mice relative to wild-type mice. In experiments with a high-fat diet or methyl-supplemented diet, body weight did not differ significantly with the genotypes. Gene expression levels of inflammatory cytokines such as tumor necrosis factor-alpha (TNF-alpha) and monocyte chemoattractant protein-1 (MCP-1) were higher in Dnmt3a mice than in wild-type mice on a high-fat diet. This study suggests that increased expression of Dnmt3a in the adipose tissue may contribute to obesity-related inflammation. The data highlight the potential role of Dnmt3a in the adult tissue as well as in the developing embryo and cancer.

Regulation of SREBP1c gene expression in skeletal muscle: role of retinoid X receptor/liver X receptor and forkhead-O1 transcription factor

Sterol regulatory element binding protein 1c (SREBP1c) is a master regulator of lipogenic gene expression in liver and adipose tissue, where its expression is regulated by a heterodimer of nuclear receptor-type transcription factors retinoid X receptor-alpha (RXRalpha) and liver X receptor-alpha (LXRalpha). Despite the potential importance of SREBP1c in skeletal muscle, little is known about the regulation of SREBP1c in that setting. Here we report that gene expression of RXRgamma is markedly decreased by fasting and is restored by refeeding in mouse skeletal muscle, in parallel with changes in gene expression of SREBP1c. RXRgamma or RXRalpha, together with LXRalpha, activate the SREBP1c promoter in vitro. Moreover, transgenic mice overexpressing RXRgamma specifically in skeletal muscle showed increased gene expression of SREBP1c with increased triglyceride content in their skeletal muscles. In contrast, transgenic mice overexpressing the dominant-negative form of RXRgamma showed decreased SREBP1c gene expression. The expression of Forkhead-O1 transcription factor (FOXO1), which can suppress the function of multiple nuclear receptors, is negatively correlated to that of SREBP1c in skeletal muscle during nutritional change. Moreover, transgenic mice overexpressing FOXO1 specifically in skeletal muscle exhibited decreased gene expression of both RXRgamma and SREBP1c. In addition, FOXO1 suppressed RXRalpha/LXRalpha-mediated SREBP1c promoter activity in vitro. These findings provide in vivo and in vitro evidence that RXR/LXR up-regulates SREBP1c gene expression and that FOXO1 antagonizes this effect of RXR/LXR in skeletal muscle.

Structural significance of N-glycans of the zona pellucida on species-selective recognition of spermatozoa between pig and cattle

The zona pellucida that surrounds the mammalian oocyte plays a role in species-selective sperm-egg interactions. In the pig and cattle, the zona pellucida consists of ZPA, ZPB and ZPC. Sperm binding activity of porcine zona glycoproteins is conferred by tri- and tetra-antennary complex-type in cattle it is conferred by a high-mannose-type chain o f f ive mannose residues. Non-reducing terminal residues of these N-linked chains, beta-galactosyl residues in pig and alpha-mannosyl residues in cattle, are involved in the binding of zona glycoproteins to respective spermatozoa. The major N-linked chains of recombinant porcine ZPB expressed using the baculovirus-Sf9 cell expression system are pauci- and high-mannose-type chains that are different in structure to the major neutral N-linked chains of the porcine zona but similar to those of the bovine zona. The mixture of porcine ZPB/ZPC co-expressed in Sf9 cells binds to bovine sperm but not to porcine sperm, indicating an essential role of the N-linked chains in species-selective recognition of sperm in pig and cattle. Asn to Asp mutations at either of two of the N-glycosylation sites of ZPB, residue 203 or 220, significantly reduce the sperm-binding activity of the ZPB/ZPC mixture, while a similar mutation at Asn333 has no effect on binding. These results coincide with our previous report that tri- and tetra-antennary complex-type chains are localized at Asn220 in native porcine ZPB and suggest that the N-glycans located in the N-terminal half of the ZP domain of porcine ZPB are involved in sperm-zona binding.

Depression of sink activity precedes the inhibition of biomass production in tomato plants subjected to potassium deficiency stress

Tomato [Solanum lycopersicum (formerly Lycopersicon esculentum) L. cv. Momotarou] plants were grown hydroponically inside the greenhouse of Hiroshima University, Japan. The adverse effects of potassium (K) deficiency stress on the source-sink relationship during the early reproductive period was examined by withdrawing K from the rooting medium for a period of 21 d. Fruits and stem were the major sink organs for the carbon assimilates from the source. A simple non-destructive micro-morphometric technique was used to measure growth of these organs. The effect of K deficiency was studied on the apparent photosynthesis (source activity), leaf area, partitioning (13)C, sugar concentration, K content, and fruit and stem diameters of the plant. Compared with the control, K deficiency treatment severely decreased biomass of all organs. The treatment also depressed leaf photosynthesis and transport of (13)C assimilates, but the impact of stress on these activities became evident only after fruit and stem diameter expansions were down-regulated. These results suggested that K deficiency diminished sink activity in tomato plants prior to its effect on the source activity because of a direct effect on the water status of the former. The lack of demand in growth led to the accumulation of sugars in leaves and concomitant fall in photosynthetic activity. Since accumulation of K and sugars in the fruit was not affected, low K levels of the growing medium might not have affected the fruit quality. The micro-morphometric technique can be used as a reliable tool for monitoring K deficiency during fruiting of tomato. K deficiency directly hindered assimilate partitioning, and the symptoms were considered more detrimental compared with P deficiency.

Dose-dependency of Life Span Prolongation of F344/DuCrj Rats Injected with (−)deprenyl

The effect of (-)deprenyl (D) on prolonging survival has previously been reported in different species of animals. In rats, three studies reported a positive effect, while one study reported a shortening of life spans. In the present study, we attempted to clarify past discrepancies in the results based on the speculation that there exists a certain effective dose range for this effect of the drug. F344/DuCrj rats of both sexes began to receive subcutaneous (s.c.) injections of D at the age of 18 months at a dose of 0.25 mg/kg/injection (inj.), 3 times a week. Control animals were given a vehicle (a saline solution). Average life spans of animals (days) were significantly increased in both male (895 +/- 109.7, n=30; 967.8 +/- 88.6, n=30, control vs. D treated, P<0.01, t-test) and female (924.7 +/- 132.2, n=38; 987.1 +/- 133.4, n=39, P<0.05) rats by 8.1% and 6.7%, respectively. We have previously reported that a dose of 0.5mg/kg/inj. (s.c.) significantly increased the life span of male F344 rats, while a dose of 1.0 mg/kg/inj. somewhat shortened the life span, although the difference was not statistically significant. The results of the present study coupled with our previous reports clearly indicate that a proper dose of D within a certain dose range can significantly increase the life span of animals of both sexes, but that a greater dose becomes less effective and may actually adversely affect the life span of rats. The presence of this effective dose range of D may explain discrepancies in the effect of D on life spans of animals previously reported.

Participation of the nonreducing terminal beta-galactosyl residues of the neutral N-linked carbohydrate chains of porcine zona pellucida glycoproteins in sperm-egg binding

The zona pellucida (ZP) surrounding the mammalian oocyte is composed of three glycoprotein components (ZPA, ZPB, and ZPC). Mammalian sperm bind to carbohydrate chains of a ZP glycoprotein in the initial phase of fertilization. Sperm-ligand carbohydrate chains have been characterized in mouse, cow, and pig. In pigs, triantennary/tetraantennary neutral complex-type chains from ZPB/ZPC mixture possess stronger sperm-binding activity than those of biantennary chains (Kudo et al., 1998: Eur J Biochem 252:492-499). Most of these oligosaccharides have beta-galactosyl residues at the nonreducing ends. This study used two in vitro competition assays to investigate the participation of the nonreducing terminal beta-galactosyl residues of the ligand active chains in porcine sperm binding. The removal of the nonreducing terminal beta-galactosyl residues from either the ligand active carbohydrate chains or endo-beta-galactosidase-digested glycoproteins significantly reduced their inhibition of sperm-egg binding, indicating that the beta-galactosyl residues at the nonreducing ends are involved in porcine sperm-egg binding. A correlation between the sperm-binding activity and in vitro fertilization rate is also presented.

Characterization of Oita virus 296/1972 of Rhabdoviridae isolated from a horseshoe bat bearing characteristics of both lyssavirus and vesiculovirus

Oita virus 296/1972 was isolated from the blood of a wild horseshoe bat, Rhinolophus cornutus (Temminck) in 1972. We investigated the pathogenicity of this virus in mice in relation to its histological, immunohistochemical and ultrastructural characteristics and the entire sequence of nucleoprotein gene. This virus caused lethal encephalitis in mice through intracerebral route. This susceptibility of mice was until 3 weeks of age. Immunohistochemical analysis using the convalescent sera obtained from survived adult mice after intracerebral inoculation revealed that many neurons were positive in the cytoplasm, besides no cross reactivity with normal and rabies virus-infected mouse brain tissues to this anti-sera. Ultrastructural analysis disclosed many bullet-shaped and enveloped virions in neurons. These morphological characteristics of the virions are consistent of that of viruses in the family Rhabdoviridae. Budding from endoplasmic membrane suggests that this virus has a similarity with lyssaviruses. Molecular analysis of cDNA coding a tentative nucleoprotein sequence revealed homology with those of viruses in the family Rhabdoviridae. Distance matrix analysis of this gene sequence with those of other rhabdoviruses isolated from mammals disclosed the discrete position of this virus in the phylogenic tree of rhabdoviridae infecting mammals and we renamed this virus as Oita rhabdovirus.

Inhibitory effect of somatostatin on cholecystokinin release is independent of luminal cholecystokinin-releasing factor content in conscious rats

INTRODUCTION

Exclusion of bile-pancreatic juice from the intestine increases pancreatic secretion via cholecystokinin (CCK) release in conscious rats. Luminal CCK-releasing factor (LCRF), purified from rat intestinal secretions, is an intraluminal regulator of CCK secretion during bile-pancreatic juice diversion.

AIMS

Because somatostatin is a potent inhibitor of CCK release and pancreatic secretion, the inhibitory effect of somatostatin on LCRF was examined.

METHODOLOGY

Rats were prepared with bile and pancreatic cannulae and two duodenal cannulae and with an external jugular vein cannula. The experiments were conducted without anesthesia. After 1.5-hour basal collection of pancreatic juice with bile-pancreatic juice return, bile-pancreatic juice was diverted for 2 hours, during which time somatostatin (2, 10 nmol/kg/h) was infused intravenously. The rats were killed before and 1 and 2 hours after bile-pancreatic juice diversion. To examine the effect of luminal somatostatin, 50 or 200 nmol/kg/h of somatostatin was infused into the duodenum. The plasma CCK and luminal content of LCRF were measured by specific radioimmunoassays.

RESULTS

Bile-pancreatic juice diversion significantly increased pancreatic secretion, plasma CCK, and LCRF levels. Intravenous infusion of somatostatin inhibited CCK release and pancreatic secretion, but not LCRF content. Luminal administration of somatostatin did not show any effect.

CONCLUSION

Inhibitory effect of circulating somatostatin on CCK release and pancreatic secretion is independent of LCRF content.

Early full donor myeloid chimerism after reduced-intensity stem cell transplantation using a combination of fludarabine and busulfan

BACKGROUND AND OBJECTIVES

The aim of this study was to evaluate lineage-specific chimerism reconstitution after reduced-intensity allogeneic stem cell transplantation (RIST) using a combination of fludarabine (30 mg/m2 for 6 days) and busulfan (4 mg/kg for 2 days).

DESIGN AND METHODS

We prospectively enrolled 8 consecutive patients with hematologic malignancies who were not candidates for conventional transplantation because of either high age or organ dysfunction. Host-donor chimerism was evaluated using polymerase chain reaction-based amplification of a polymorphic short tandem repeat region.

RESULTS

All of our patients achieved engraftment within a median of 11 days after transplantation. On day 30, full donor myeloid cell chimerism (>90%) was achieved in 7 patients whereas full donor T-cell chimerism was achieved in only one patient. Thus, in contrast to other reported results, full donor chimerism was achieved earlier in the myeloid lineage than the T-cell lineage. On day 60, however, T-cell chimerism caught up with myeloid chimerism. Two patients developed grade II-IV acute graft-versus-host disease (GVHD) before the detection of full donor T-cell chimerism.

INTERPRETATION AND CONCLUSIONS

Our findings suggest that the kinetics of lineage-specific chimerism depend on the agents used in the conditioning regimen, and may provide insight into the chimerism kinetics and pathogenesis of GVHD. Thus, the strategy for controlling immunosuppression after RIST should be modified according to the type of conditioning regimen applied.

Importance of CCK-A receptor for gallbladder contraction and pancreatic secretion: a study in CCK-A receptor knockout mice

Bile and pancreatic secretions were determined in a CCK-A receptor deficient mouse mutant generated by gene targeting in embryonic stem cells. The targeting vector contained lacZ and neo insertions in exon 2. Under the urethane anesthesia, the common bile duct was cannulated, and the mixture of bile-pancreatic juice was collected every 30 min. After the 1 h basal secretion, CCK-8 (0.5 and 1.0 nmol/kg), acetylcholine (500 nmol/kg), and neuromedin C (1.0 micromol/kg) were injected subcutaneously, and the secretions were collected following 1 h. Amylase and bile acid outputs were determined as parameters of pancreatic secretion and gallbladder contraction, respectively. In some CCK-A receptor (+/-) animals, LacZ staining was performed. CCK-8 significantly increased amylase and bile acid outputs in CCK-A receptor (+/+) and (+/-) mice, whereas no response was observed in (-/-) mice. Neuromedin C and acetylcholine increased amylase secretion in CCK-A receptor (-/-) mice similar to (+/-) and (+/+) mice. The same doses of neuromedin C and acetylcholine could not increase bile acid secretion. The gallbladder smooth muscles, pancreatic acinar cells, duct cells, and islets were stained by LacZ. CCK and CCK-A receptor are important for pancreatic secretion and gallbladder contraction. Neuromedin C and acetylcholine may compensate pancreatic function, but not gallbladder contraction.

Induction of tumor specific cytotoxic T lymphocytes in prostate cancer using prostatic acid phosphatase derived HLA-A2402 binding peptide

PURPOSE

Human prostatic acid phosphatase is a prostate specific differentiation antigen. Prostatic acid phosphatase levels increase in the serum of patients with prostate cancer and its peptide from positions 299 to 307 (PAP 299-307) is recognized by HLA-A2 restricted cytotoxic T lymphocytes. We investigated whether HLA-A2402 binding prostatic acid phosphatase derived peptides induce HLA-A2402 restricted, tumor specific cytotoxic T lymphocytes from the peripheral blood mononuclear cells of patients with prostate cancer.

MATERIALS AND METHODS

Peptide binding activity was measured with RMA-S-A*A2402 cell lines and flow cytometry. Cytotoxic T-lymphocyte activity of the peripheral blood mononuclear cells of patients with prostate cancer and healthy donors was measured by interferon-gamma and (51)creatinine release assays. Prostatic acid phosphatase expression in the tumor cell lines at the messenger RNA and protein levels was investigated by reverse transcriptase-polymerase chain reaction and immunohistochemical analysis, respectively.

RESULTS

An HLA-A2402 binding, prostatic acid phosphatase derived peptide consisting of the prostatic acid phosphatase amino acid sequence from positions 213 to 221 (PAP 213-221, LYCESVHNF) showed the ability to induce HLA-A2402 restricted and tumor specific cytotoxic T lymphocytes, which are cytoxic to prostatic acid phosphatase positive tumor cells from the peripheral blood mononuclear cells of patients with prostate cancer.

CONCLUSIONS

PAP 213-221 may be appropriate as a cancer vaccine for specific immunotherapy in patients with HLA-A2402 positive prostate cancer.

Synthesis of lipid A type pyran carboxylic acids with ether chains and their biological activities

Synthesis of lipid A type pyran carboxylic acids having ether chains at both the C-3' and C-4 positions and their bioactivities toward human U937 cells are described.

Successful application of nonmyeloablative transplantation for paroxysmal nocturnal hemoglobinuria

OBJECTIVE

Paroxysmal nocturnal hemoglobinuria (PNH) is an acquired clonal hematopoietic stem cell disorder that manifests as hemolytic anemia, venous thrombosis, and deficient hematopoiesis. Although allogeneic hematopoietic stem cell transplantation is considered the only curative therapeutic measure, transplant-related mortality is not negligible. Several studies supported the use of nonmyeloablative stem cell transplantation (NST) for patients of advanced age or with organ dysfunction. Hence, we used NST in a PNH patient who suffered from acute renal failure due to repeated episodes of hemolysis.

MATERIALS AND METHODS

We performed NST using a conditioning regimen consisting of cladribine 0.11 mg/kg x 6, busulfan 4 mg/kg x 2, and rabbit anti-thymocyte globulin 2.5 mg/kg x 2. He received peripheral blood stem cells from his human leukocyte antigen-matched brother. Prophylaxis against graft-vs-host disease was performed with cyclosporine A alone. Chimerism of peripheral blood mononuclear cells was evaluated serially using short tandem repeat analysis and flow cytometry.

RESULTS

No meaningful regimen-related toxicities were documented. Donor chimerism of 90 to 100% was achieved on day 14 and thereafter. The patient is doing well, without any recurrence of hemolysis 6 months after transplant. Follow-up chimerism studies confirmed stable and functioning donor-type hematopoiesis.

CONCLUSIONS

NST may become a safe and curative approach in patients with PNH. Further studies are needed to establish the role of NST for treatment of PNH.

Synthesis of GLA-60 type pyran carboxylic acids with an alkyl chain instead of an ester chain as LPS-antagonists

Synthesis of GLA-60 type pyran carboxylic acid analogues with an alkyl chain instead of an ester chain and their LPS-antagonist activity toward human U937 cells are described.

Common properties for propargylamines of enhancing superoxide dismutase and catalase activities in the dopaminergic system in the rat: implications for the life prolonging effect of (-)deprenyl

(-)Deprenyl has been reported to prolong the life span of different animal species. Further, the drug effectively increases antioxidant enzyme activities such as superoxide dismutase (SOD) and catalase (CAT) in brain dopaminergic regions. We have found that the effect of the drug on antioxidant enzyme activities is highly dose dependent, increasing with an increasing dose, however, a higher dose becomes less effective and an excessive dose becomes adversely effective. Most importantly, an optimal dose for the effect varies widely depending on animal species, strain, sex, age and duration of the treatment, which may at least partly explain discrepancies reported among different studies in the past. From the parallelism of the dose-effect relationship of the drug between life span extension and increasing endogenous antioxidant enzyme activity, we have suggested that the above two effects of (-)deprenyl may be causally related. This review summarizes our past series of studies and also reports our very recent observation that other propargylamines such as rasagiline and (R)-N-(2-heptyl)-N-methylpropagylamine (R-2HMP) also share the property of enhancing antioxidant enzyme activities. Further, our most recent study has found that these propargylamines increase antioxidant enzyme activities not only in brain dopaminergic regions but in extra-brain dopaminergic tissues such as the heart and kidneys. These observations are discussed in relation to the life prolonging effect of (-)deprenyl reported in the past.

Do antioxidant strategies work against aging and age-associated disorders? Propargylamines: a possible antioxidant strategy

The free radical theory of aging was initially proposed by Harman half a century ago primarily to explain biological aging processes. Although administration of so-called antioxidant chemicals, which have been tested in the past for several decades, turned out to be mostly ineffective in prolonging the life spans of animals, the same theory of age-associated diseases appears to be increasingly supported in the last two decades. Despite these difficulties, the success in extending life span of 4 different animal species (mice, rats, hamsters, and dogs) with (-)deprenyl (including a study of our group) indicates that there might exist another type of antioxidant strategy in addition to a simple administration of antioxidant chemicals. (-)Deprenyl has also been shown to increase superoxide dismutase (SOD) and catalase (CAT) activities selectively in brain dopaminergic tissues. Interestingly, we have recently shown that another propargylamine, rasagiline not only increases antioxidant enzyme activities (CAT and SOD) in brain dopaminergic regions as (-)deprenyl does, but also increases CAT and SOD activities in extrabrain catecholaminergic systems such as the heart and kidneys as well. These recent observations coupled with previous observations on the life span of animals with (-)deprenyl suggest that pharmacological modulation of endogenous antioxidant enzyme activities could be one potential antioxidant strategy against aging and age-associated disorders. If the causal relationship between the two effects of (-)deprenyl exists as we hypothesized, we might be able to advance the elucidation of mechanism(s) of aging based on the free radical theory of aging.

A high dose of long term treatment with deprenyl loses its effect on antioxidant enzyme activities as well as on survivals of Fischer-344 rats

The survival rate of male Fischer-344/Du rats treated chronically with high doses of deprenyl was investigated. Eighteen month old rats were treated with 1 mg/kg s.c. deprenyl 3 times per week for 13 months. At the age of 31 months, treated rats showed a greater mortality rate with three of 12 rats surviving, while in saline-treated control animals seven of 12 animals survived. No significant differences in superoxide dismutase (SOD) or catalase (CAT) activities in brain regions of control and treated animals were seen at 31 months of age. In contrast, when 27 month old rats were treated in the same manner for one month, significant increases in SOD (both Cu,Zn- and Mn-) and CAT activities were found in substantia nigra, striatum and cerebral cortex, but not in hippocampus. This effect was produced with a wide range of deprenyl doses (0.25-2 mg/kg, but not 4 mg/kg). Although a causal relationship between the two different effects of the drug, i.e. 1) increases in antioxidant enzyme activities and 2) the prolongation of survival of animals, has not been directly demonstrated, the loss of both effects with the high dose of the drug in the present experiment may be taken as circumstantial evidence for their causal relationship.

Overexpression of cholecystokinin-B/gastrin receptor gene in the stomach of naturally occurring cholecystokinin-A receptor gene knockout rats

We examined the cholecystokinin (CCK)-B/gastrin receptor, H+/K+-ATPase and somatostatin gene expression, the histology and immunohistochemistry of gastrin and somatostatin of the stomach, plasma gastrin levels, and gastric acid secretion in naturally occurring CCK-A receptor gene knockout (Otsuka Long-Evans Tokushima fatty, OLETF) rats. The CCK-B/ gastrin receptor, H+/K+-ATPase and somatostatin mRNAs were determined by Northern transfer analysis. The gastric acid secretion and the plasma gastrin level were measured in vivo. The levels of CCK-B/gastrin receptor mRNA in the forestomach and the glandular stomach in OLETF rats were 2-fold higher than those of control rats, although those of H+/ K+-ATPase and somatostatin mRNAs were not different. Histological examination revealed thickening of the fundic mucosa, and hyperplasia and hypertrophy of parietal cells, although immunohistochemistry of gastrin and somatostatin revealed no significant difference from the control rats. Gastric acid secretion stimulated by gastrin or histamine was enhanced, whereas the fasting plasma gastrin level was not significantly different from that in control rats. The overexpression of CCK-B/gastrin receptor mRNA and the hyperfunction of parietal cells were observed in rats without CCK-A receptor gene expression.

Synthesis of NG-061 and its analogs, and their biological evaluation as an enhancer of nerve growth factor

A novel potentiator of nerve growth factor (NGF), NG-061, which had been isolated from the fermentation broth of Penicillium minioluteum F-4627, was synthesized from methoxybenzoquinone and phenylacetylhydrazine in a single step. A series of acyl hydrazone derivatives were also synthesized and their potentiator activity of neurotrophic effect of NGF on neurite outgrowth was evaluated by assay with a rat pheochromocytoma cell line PC12.

The diurnal rhythm of energy expenditure differs between obese and glucose-intolerant rats and streptozotocin-induced diabetic rats

Otsuka Long Evans Tokushima Fatty (OLETF) rats were developed as a model of noninsulin-dependent diabetes mellitus (NIDDM) with mild obesity. Changes in carcass composition and in the daily profile of energy expenditure were examined before and after manifestation of diabetes (8 and 24 wk, respectively), and compared with the normal control Long Evans Tokushima (LETO) rats and streptozotocin (STZ)-induced diabetic LETO rats. OLETF rats had greater body weights than LETO rats and significantly greater absolute and relative fat weights. A diurnal rhythm of energy expenditure associated with two peaks was observed in LETO rats, but the two peaks were not apparent in OLETF rats at 24 wk of age. A diurnal rhythm associated with one peak was observed in STZ-induced diabetic LETO rats. Energy derived from fat constituted this peak; the pattern of the daily energy expenditure was significantly different from that of either nontreated LETO or OLETF rats at 24 wk of age. NIDDM in OLETF rats at 24 wk of age has only a small role in modification of the diurnal rhythm of energy expenditure, whereas STZ-induced diabetes significantly affected the rhythm.

Molecular analysis of zebrafish photolyase/cryptochrome family: two types of cryptochromes present in zebrafish

BACKGROUND

Cryptochromes (CRY), members of the DNA photolyase/cryptochrome protein family, regulate the circadian clock in animals and plants. Two types of animal CRYs are known, mammalian CRY and Drosophila CRY. Both CRYs participate in the regulation of circadian rhythm, but they have different light dependencies for their reactions and have different effects on the negative feedback loop which generates a circadian oscillation of gene expression. Mammalian CRYs act as a potent inhibitor of transcriptional activator whose reactions do not depend on light, but Drosophila CRY functions as a light-dependent suppressor of transcriptional inhibitor.

RESULTS

We cloned seven zebrafish genes that carry members of the DNA photolyase/cryptochrome protein family; one (6-4)photolyase and six cry genes. A sequence analysis and determination of their in vitro functions showed that these zebrafish cry genes constitute two groups. One has a high sequence similarity to mammalian cry genes and inhibits CLOCK:BMAL1 mediated transcription. The other, which has a higher sequence similarity to the Drosophila cry gene rather than the mammalian cry genes, does not carry transcription inhibitor activity. The expressions of these cry genes oscillate in a circadian manner, but their patterns differ.

CONCLUSIONS

These findings suggest that functionally diverse cry genes are present in zebrafish and each gene has different role in the molecular clock.

Mechanism of delayed gastric emptying in naturally occurring CCK-A receptor gene knockout (OLETF) rats

We recently found a specific strain of rats (OLETF rats) in which CCK-A receptor gene expression is lacking because of a genetic abnormality. As delayed gastric emptying has been reported in this strain, we examined its mechanism. A liquid gastric load containing phenol red was administered using an orogastric tube into the stomach in OLETF and control (LETO) rats. The stomach was removed 0, 15, 30 and 45 min after meal ingestion and the content of phenol red was measured to estimate the rate of gastric emptying. Pretreatment of reserpine enhanced gastric emptying in both strains. A tenfold dose of reserpine was required in OLETF rats to induce a similar effect to LETO rats. The plasma noradrenalin level was significantly higher in OLETF than LETO rats. When the smooth muscle of the stomach was isolated and contraction in vitro was examined, the smooth muscle functions were not deteriorated in OLETF rats. The thickness of muscle determined by hematoxylin-eosin staining was not different between strains. It is suggested that the delayed gastric emptying in OLETF rats may be due to increased sympathetic nerve function.

Enhancing effect of rasagiline on superoxide dismutase and catalase activities in the dopaminergic system in the rat

Rasagiline [N-propargyl-l(R)-aminoindan] is a selective irreversible MAO-B inhibitor as is (-)deprenyl. The effect of the drug on antioxidant enzyme activities on dopaminergic tissue was examined in male F-344 rats (8.5-months-old). Two experimental groups were infused subcutaneously with rasagiline saline solutions by means of osmotic minipumps implanted subcutaneously in the back of the rats. Control animals were also similarly implanted with saline filled mini-pumps. Three-and-one-half weeks later, animals were sacrificed and selected tissue samples removed from brain, kidney and heart. Two doses of rasagiline (0.5 mg/kg/day, 1.0 mg/kg/day, both for 3.5 weeks) significantly increased catalase activities about 2-fold in substantia nigra and striatum but not in hippocampus. Interestingly, in both renal cortex and medulla. catalase (CAT) activities were significantly increased. Both Mn- and Cu,Zn-superoxide dismutase (SOD) activities were increased 2 to 4 fold in substantia nigra, striatum and renal cortex and heart. Several groups, including our own have reported an extension of survival of deprenyl-treated animals of different species. Although the mechanism(s) of the life extension by deprenyl remains unresolved, it would be interesting to investigate the effect of rasagiline on the survival of animals, since deprenyl also was shown to increase antioxidant enzyme activities in brain dopaminergic regions.

Oral administration of a synthetic trypsin inhibitor increases pancreatic duct function in CCK-A receptor-deficient rats

The effects of oral administration of a synthetic trypsin inhibitor on bicarbonate secretion were examined in cholecystokinin A (CCK-A) receptor-deficient (OLETF) rats and compared with Wistar rats. Rats were fed chow containing 0.1% trypsin inhibitor for 7 days. Rats were prepared with cannulae draining bile and pancreatic juice separately and with duodenal and extrajugular vein cannulae after 3-day trypsin inhibitor ingestion. Then the animals were maintained in Bollman cages, and the experiments were conducted 4 days after surgery. After 1.5 h of basal secretion with bile-pancreatic juice return, bile-pancreatic juice was diverted for 2 h. The responses of bicarbonate secretion to bile-pancreatic juice diversion were significantly enhanced in rats treated with trypsin inhibitor compared with those given a control diet, whereas responses of fluid and protein secretion were not affected in OLETF rats. The response of protein secretion, but not those of fluid or bicarbonate secretion, was enhanced in Wistar rats by treatment with trypsin inhibitor. Carbonic anhydrase II gene expression was increased by 7-day treatment with trypsin inhibitor only in OLETF rats, and not in Wistar rats.

Inhibitory effect of central calcitonin-gene related peptide (CGRP) on pancreatic secretion in conscious rats

The inhibitory effect of central administration of calcitonin-gene related peptide (CGRP) on pancreatic secretion stimulated by bile-pancreatic juice diversion was determined in conscious rats. Rats were prepared with separate cannulae for draining bile and pancreatic juice and with a duodenal cannula and an extrajugular vein cannula. In addition, another cannula was stereotactically implanted into the left lateral cerebral ventricle. Rats were placed in restraint cages and experiments were conducted 4 d after the operation without anesthesia. An injection of CGRP (1 nmol/10 microl) into the left lateral cerebral ventricle (i.c.v.) inhibited pancreatic secretion as well as cholecystokinin (CCK) release induced by bile-pancreatic juice diversion. Intravenous infusion of alpha- and beta-adrenergic receptor antagonist, phentolamine and propranolol did not reverse the inhibition of pancreatic secretion. Intravenous infusion of CGRP did not affect pancreatic secretion or plasma CCK concentrations. The inhibitory action of central CGRP (i. c.v.) on pancreatic secretion and CCK release stimulated by bile-pancreatic juice diversion is partially mediated by an alpha-adrenergic mechanism, although its precise mechanism has not been elucidated.

Synthesis and biological activities of lipid A-type pyrancarboxylic acid derivatives

The synthesis of lipid A-type pyrancarboxylic acid derivatives, which have a carboxylic acid group in the anomeric position of the reducing part of the disaccharide instead of the phosphate group in lipid A, is described. One of the compounds thus synthesized, which has an acyl substitution pattern similar to that of Escherichia coli lipid A, showed lipopolysaccharide (LPS)-agonistic activity. The other, which contains four lipid chains in the molecule, exhibited strong LPS-antagonistic activity toward human monoblastic U937 cells.

Lymphatic lipid transport is not impaired in ageing rat intestine

Lymphatic lipid transport in the intestine of adult and ageing rats was compared. Adult (8-10 months old) and old (24-26 months old) male Wistar rats were cannulated into the mesenteric lymph under ethrane anesthesia. On the following day, lipid emulsion containing 35.4 mg/h of olive oil was infused intraduodenally for 7 h and lymph collected hourly was assayed for triglyceride and apolipoprotein A-IV (apo A-IV). The results showed there was no difference in lymphatic lipid and apo A-IV transport between adult and old rats. Since apo A-IV synthesis in the enterocytes is linked to the intracellular assembly of lipoprotein, it is likely that in addition to lymphatic transport, production of chylomicrons is not impaired in ageing rats.

Regulation of pancreatic secretion by vagal nerve during short-term duct occlusion in conscious rats

The basal exocrine secretion of the pancreas is maintained at a constant level in conscious rats. We examined the changes in basal secretion with respect to the effect of various time periods of pancreatic duct occlusion (PDL). Male Wistar rats were prepared with cannulae that separately drained bile and pancreatic juice as well as with a duodenal cannula. Rats were placed in restraint cages, and experiments were conducted without anesthesia 4 days after the operation. Cholecystokinin (CCK) release was artificially prevented by the continuous infusion of bile with trypsin into the duodenal lumen throughout the experimental period to avoid the modification of pancreatic response by CCK. After 2-h basal collection, a pancreatic secretion was interrupted for 0.5-4 h, and then the collection of pancreatic juice was initiated again for an additional 2-4.5 h. The pancreatic secretion after the reopening of the 0.5-to 3-h PDL was comparable to basal secretion levels. However, protein secretion was significantly inhibited after the removal of 4-h PDL. Both vagotomy and capsaicin treatment abolished this inhibition, and the protein secretion after 1-h PDL in vagotomized rats increased 1.5-fold high compared with the basal value. These observations indicate that protein secretion was ceased during PDL via vagal nerve, and this may be a self-protective mechanism.

Expression of PDGF-beta receptor, EGF receptor, and receptor adaptor protein Shc in rat osteoblasts during spaceflight

A number of studies have indicated that microgravity induces osteopenia and modulates functions of mammalian cells. However, the molecular mechanisms underlying these effects of microgravity are still unknown. Rat osteoblasts were cultured for 4 and 5 days during Shuttle-Spacelab flight, and fixed by guanidine isothiocyanate solution on board after treatment with 1alpha, 25 (OH)2 vitamin D3. The mRNA levels for platelet-derived growth factor (PDGF)-beta receptor, epidermal growth factor (EGF) receptor, the growth factor receptor adaptor protein Shc, and c-fos were determined using the method of quantitative reverse transcription-polymerase chain reaction. The mRNA levels for EGF receptor were not altered by microgravity. However, the mRNA levels for PDGF-beta receptor, Shc, and c-fos were decreased to 62, 55 and 25% on the 4th day of flight, and 47, 40, and 43% on the 5th day, respectively, as compared to the corresponding ground controls. Expression of the growth factor receptor and the receptor adaptor protein was modulated in rat osteoblasts during spaceflight. Data suggest that signal transduction via growth factor receptors in rat osteoblasts is impaired by microgravity. Dysfunction of osteoblasts might be involved in spaceflight-induced osteopenia.