Pulsatile pump perfusion of pancreata before human islet cell isolation

Machine pulsatile perfusion for whole pancreas preservation might improve yield, viability, and function of human islets recovered after prolonged cold ischemia times. Four human pancreata were procured from cadaver donors (1 non-heart-beating donor) and stored in cold University of Wisconsin (UW) solution for a mean 13 hours prior to placement on a machine pulsatile perfusion device. The four pancreata were perfused for 4 hours with UW solution before undergoing islet isolation. Islets were quantified, viability was assessed, and insulin secretion was measured. Results were compared with nonpumped islet isolations stratified for cold ischemia time (CIT) <8 hours or cold ischemia time >8 hours. The islet yield for the four pumped pancreata was 3435 (+/-1951) islet equivalents/gram pancreas tissue (IEQ/g), compared with a mean yield of 5134 (+/-2700) IEQ/g and 2640 (+/-1000) IEQ/g from pancreas with <8 hours and >8 hours CIT, respectively. The mean viability after machine pulsatile perfusion was 86% (vs 74% and 74% for the <8 hour and >8 hour CIT groups). The mean viable yield (total yield x viability) was 2937 IEQ/g for machine perfusion, compared with 3799 IEQ/g and 1937 IEQ/g from pancreata with <8 hours and >8 hours CIT, respectively. The insulin secretion index of islets after machine perfusion was 6.4, compared with indices of 1.9 and 1.8 for the <8 hour and >8 hour CIT groups. This preliminary data indicates that low-flow machine pulsatile perfusion of pancreata with prolonged cold ischemia time can result in excellent yield, viability, and function.

Antitumor agents--CLXXV. Anti-tubulin action of (+)-thiocolchicine prepared by partial synthesis

(+)-Thiocolchicine (2b) was prepared from (+/-)-colchicine (1) in a five-step reaction sequence that included chromatographic separation of appropriate camphanylated diastereomers. Acid hydrolysis of the (+)-diastereomer, followed by acetylation, yielded the desired product 2b. (+)-Thiocolchicine has 15-fold lower inhibitory activity against tubulin polymerization than (-)-thiocolchicine, and is 29-fold less potent for inhibiting growth of human Burkitt lymphoma cells. The enantiomer 2a, prepared from the (-)-camphanylated diastereomer, had potent activity in all assays comparable to that of (-)-thiocolchicine prepared by other methods. These results support the hypothesis that the proper configuration of colchicine-related compounds is an important requirement for their anti-tubulin action.

Neuroprotection of neurotrophin-3 against focal cerebral ischemia/reperfusion injury is regulated by hypoxia-responsive element in rats

Exogenous delivery of the neurotrophin-3 (NT-3) gene may provide a potential therapeutic strategy for ischemic stroke. To investigate the neuroprotective effects of NT-3 expression controlled by 5HRE after focal cerebral ischemia, we constructed a recombinant retrovirus vector (RV) with five copies of hypoxia-responsive elements (5HRE or 5H) and NT-3 and delivered it to the rat brain. Three groups of rats received RV-5H-NT3, RV-5H-EGFP or saline injection. Three days after gene transfer, the rats underwent 90min of transient middle cerebral artery occlusion (tMCAO), followed by 1-28days of reperfusion. Three days after tMCAO, brain NT-3 expression was significantly increased in the RV-5H-NT3-transduced animals compared with the RV-5H-EGFP or saline group, and brain infarct volume was smaller in the RV-5H-NT3-transduced group than the RV-5H-EGFP or saline group. The percentage of TUNEL-positive cells was reduced in RV-5H-NT3-transduced brains compared with the RV-5H-EGFP or saline group 3 and 7days after tMCAO. Furthermore, the neurological status of RV-5H-NT3-transduced rats was better than that of RV-5H-EGFP- or saline-transduced animals from 1day to 4weeks after tMCAO. Our results demonstrated that 5HRE could modulate NT-3 expression in the ischemic brain environment and that the up-regulated NT-3 could effectively improve neurological status following tMCAO due to decreased initial damage. To avoid unexpected side effects, 5HRE-controlled gene expression might be a useful tool for gene therapy of ischemic disorders in the central nervous system.

Immune tolerance induced by platelet-targeted factor VIII gene therapy in hemophilia A mice is CD4 T cell mediated

Essentials The immune response is a significant concern in gene therapy. Platelet-targeted gene therapy can restore hemostasis and induce immune tolerance. CD4 T cell compartment is tolerized after platelet gene therapy. Preconditioning regimen affects immune tolerance induction in platelet gene therapy.

SUMMARY

Background Immune responses are a major concern in gene therapy. Our previous studies demonstrated that platelet-targeted factor VIII (FVIII) (2bF8) gene therapy together with in vivo drug selection of transduced cells can rescue the bleeding diathesis and induce immune tolerance in FVIIInull mice. Objective To investigate whether non-selectable 2bF8 lentiviral vector (LV) for the induction of platelet-FVIII expression is sufficient to induce immune tolerance and how immune tolerance is induced after 2bF8LV gene therapy. Methods Platelet-FVIII expression was introduced by 2bF8LV transduction and transplantation. FVIII assays and tail bleeding tests were used to confirm the success of platelet gene therapy. Animals were challenged with rhF8 to explore if immune tolerance was induced after gene therapy. Treg cell analysis, T-cell proliferation assay and memory B-cell-mediated ELISPOT assay were used to investigate the potential mechanisms of immune tolerance. Results We showed that platelet-FVIII expression was sustained and the bleeding diathesis was restored in FVIIInull mice after 2bF8LV gene therapy. None of the transduced recipients developed anti-FVIII inhibitory antibodies in the groups preconditioned with 660 cGy irradiation or busulfan plus ATG treatment even after rhF8 challenge. Treg cells significantly increased in 2bF8LV-transduced recipients and the immune tolerance developed was transferable. CD4+ T cells from treated animals failed to proliferate in response to rhF8 re-stimulation, but memory B cells could differentiate into antibody secreting cells in 2bF8LV-transduced recipients. Conclusion 2bF8LV gene transfer without in vivo selection of manipulated cells can introduce immune tolerance in hemophilia A mice and this immune tolerance is CD4+ T cell mediated.

p(21WAF1/CIP1) expression in breast cancers: associations with p53 and outcome

p21(WAF1/CIP1) is transcriptionally activated by wt p53 and inhibits G1 associated cyclins, a major mechanism by which p53 inhibits cellular proliferation. Archival breast cancers (798) with a median follow-up of 16.3 years were used to explore the prognostic value of p21 immunohistochemical analyses. p21 immunostaining was detected in the majority (726/798: 91%) of breast cancers as well as adjacent in situ carcinomas (125/170: 74%), hyperplastic lesions (140/349: 40%) and normal breast epithelium adjacent to carcinoma (3/89: 3%). Complete immunonegativity was observed in only 9% of invasive cancers and was associated with p53 immunopositivity (p < 0.05). Univariate analysis of all patients showed that p21 negativity was associated with a longer disease specific survival (relative risk (RR) 1.5). Node positive p21- patients also showed a longer disease free and disease specific survival as compared to tumor p21+ patients. In node negative patients, p53 positivity but not p21 alone, was significantly associated with a shortened disease free survival (RR = 1.6). Node negative patients who were p53+ p21-, in particular had the shortest disease free survival compared to other p53, p21 subgroups (i.e., p21 negativity was associated with a worse outcome). Multivariate analysis of lymph node negative patients (n > 300) demonstrated that tumor size and tumor grade were independently predictive of outcome, whereas neither p53 nor p21 were significant. For node positive patients, p21 positivity (p = 0.05), p53 positivity (p = 0.03), a higher number of positive nodes, larger tumor size, steroid receptor negativity, high proliferation rate, and erbB-2 expression were each independently associated with poor outcome. In summary, p21 negativity was inversely correlated with p53 immunopositivity in the majority of cases. p21 negative tumor patients had an improved outcome if they were node positive, whereas p21 status was not significantly associated with survival in node negative patients. This observation may be due to the reported 'uncoupling of S phase and mitosis' associated with a loss of p21 expression which may result in enhanced sensitivity to chemotherapy.

Cytoplasmic accumulation of a normally mitochondrial malonyl-CoA decarboxylase by the use of an alternate transcription start site

Malonyl-CoA decarboxylase, a normally mitochondrial enzyme, accumulates in the cytoplasm of specialized glands to cause production of multiple methyl-branched fatty acids. Evidence was presented that a single copy of the decarboxylase gene present in the goose genome codes for both the mitochondrial form found in extremely low amounts in the liver and the cytosolic form found in large amounts in uropygial glands. To elucidate how a single gene encodes both forms, the malonyl-CoA decarboxylase gene and the cDNAs for both the mitochondrial (liver) and the cytoplasmic (gland) species were cloned and sequenced. The decarboxylase gene, found in a 21-kb segment of cloned genomic DNA, is composed of five exons of 0.521, 0.118, 0.156, 0.145, and 1.93 kb interrupted by 6.9, 1.5, 0.45, and 9.3-kb introns. Exon 1 revealed two ATGs in frame 150 bp apart. cDNA for the cytoplasmic form and mitochondrial form showed identical nucleotide sequence, except that the latter was longer than the former. The longest cDNA for the cytoplasmic form of the enzyme extended only 44 bp 5' to the second ATG and the position corresponded to the transcription initiation site of the cytoplasmic form revealed by primer extension and RNase protection. The cDNA for the mitochondrial form isolated from the library extended 19 bp further upstream. Primer extension and RNase protection indicated that transcripts for the mitochondrial form initiated upstream from the first ATG. The N-terminal segment of the open reading frame initiated at the first ATG showed an amphipathic signal sequence appropriate for mitochondrial import. A putative full length mRNA for the mitochondrial form of the enzyme when translated in vitro yielded a 55-kDa primary translation product which was processed by removal of about 5 kDa during uptake into goose liver mitochondria. These results strongly suggest that in most tissues transcription initiates 5'- to the first ATG, generating a transcript that would generate a protein with an N-terminal leader for transport into mitochondria. In the uropygial gland the use of an alternate promoter generates transcripts initiated between the two ATGs and the translation product accumulates in the cytoplasm since it lacks a mitochondrial targeting sequence.

Electrophysiological effects of aconitine in rat hippocampal slices

The electrophysiological effects of aconitine were investigated in the rat hippocampal slice and compared with those of veratridine. Both alkaloids are known to bind at site 2 of sodium channels and to block its inactivation. Extracellular recordings revealed that aconitine and veratridine exert inhibitory effects on neuronal excitability. Aconitine slowly and reversibly decreased the population spike recorded in the CA1 pyramidal cell layer. The reduction of the spike amplitude was similar whether orthodromically or antidromically activated. The aconitine-induced inhibition did not differ from that of veratridine. However, following washout of aconitine, the amplitude of the antidromic spike was increased compared to the control amplitude. The veratridine-induced inhibition was only partially reversible. This inhibition was also observed during suppression of synaptic transmission by a low Ca2+/high Mg2+-medium, indicating an inhibition of axonal conductance. The results show that in the absence of synaptic transmission the antidromic (alvear) spike is more sensitive to the inhibitory action of aconitine than the presynaptic fiber spike elicited by stimulation of the Schaffer collaterals. Furthermore, it is shown that aconitine acts in an activity-dependent manner, in that the latency of onset of the inhibition is prolonged when the stimulation frequency is decreased. Field excitatory postsynaptic potentials were also suppressed by aconitine, whereas excitatory postsynaptic currents recorded by the patch clamp technique were not influenced by aconitine when cells were held at -60 mV.

A smart core-sheath nanofiber that captures and releases red blood cells from the blood

A smart core-sheath nanofiber for non-adherent cell capture and release is demonstrated. The nanofibers are fabricated by single-spinneret electrospinning of poly(N-isopropylacrylamide) (PNIPAAm), polycaprolactone (PCL) and nattokinase (NK) solution blends. The self-assembly of PNIPAAm and PCL blends during the electrospinning generates the core-sheath PCL/PNIPAAm nanofibers with PNIPAAm as the sheath. The PNIPAAm-based core-sheath nanofibers are switchable between hydrophobicity and hydrophilicity with temperature change and enhance stability in the blood. When the nanofibers come in contact with blood, the NK is released from the nanofibers to resist platelet adhesion on the nanofiber surface, facilitating the direct capture and isolation of red blood cells (RBCs) from the blood above phase-transition temperature of PNIPAAm. Meanwhile, the captured RBCs are readily released from the nanofibers with temperature stimuli in an undamaged manner. The release efficiency of up to 100% is obtained while maintaining cellular integrity and function. This work presents promising nanofibers to effectively capture non-adherent cells and release for subsequent molecular analysis and diagnosis of single cells.

Coral communities of the remote atoll reefs in the Nansha Islands, southern South China Sea

During the months of May and June in the year 2007, a survey was conducted regarding coral reef communities in the remote atolls (Zhubi Reef and Meiji Reef) of Nansha Islands, southern South China Sea. The goals of the survey were to: (1) for the first time, compile a scleractinian coral check-list; (2) estimate the total richness, coral cover, and growth forms of the community; and (3) describe preliminary patterns of community structure according to geomorphological units. Findings of this survey revealed a total of 120 species of scleractinia belonging to 40 genera, while the average coral cover was 21 %, ranging from less than 10 % to higher than 50 %. Branching and massive corals were also found to be the most important growth forms of the whole coral community, while Acropora, Montipora, and Porites were the three dominant genera in the overall region, with their contributions to total coral cover measuring 21, 22, and 23 %, respectively. Overall, coral communities of the Nansha Islands were in a relative healthy condition with high species diversity and coral cover. Spatial pattern of coral communities existed among various geomorphological units. Mean coral cover was highest in the patch reef within the lagoon, followed by the fore reef slope, reef flat, and lagoon slope. The greatest contributors to total coral cover were branching Acropora (45 %) in the lagoon slope, branching Montipora (44 %) in the reef flat, and massive Porites (51 %) in the patch reef. Coral cover in the fore reef revealed a greater range of genera than in other habitats. The leeward fore reef slope had higher coral cover (> 50 %) when compared with the windward slope (< 10 %). The coral communities of the inner reef flat were characterized by higher coral cover (27 %) and dominant branching Montipora corals, while lower coral cover (4 %) was dominated by Psammocora with massive growth forms on the outer reef flat. Destructive fishing and coral bleaching were two major threats to coral communities in the study area.

Effects of air on the segregation of particles in a shaken granular bed

Effects of interstitial air on the motions of a large intruder in a shaken granular bed are studied experimentally as a function of ambient air pressure, particle size of the bed, and the density of the intruder. It is found that the intruder always rises from the granular bed in the absence of air. However, the intruder can acquire both positive and negative buoyancy in the presence of air. Negative buoyancy can be observed only when both the density of the intruder and the particle size of the bed are small enough. This negative buoyancy can be explained by the unusual air pressure distribution found in the bed.

Transformation of chicken embryo fibroblasts by v-src uncouples beta1 integrin-mediated outside-in but not inside-out signaling

Adhesion of cells to extracellular matrix is mediated by integrin family receptors. The process of receptor-ligand binding is dependent on metabolic energy and is regulated by intracellular signals, termed inside-out signals. The strength of the initial alpha5beta1-mediated adhesion of v-src-transformed chicken embryo fibroblasts (v-srcCEF) was similar to that of normal CEF. A chemically cross-linked fibronectin substrate was able to restore cell spreading and the ability of v-srcCEF to assemble a fibronectin matrix. Over time, v-srcCEF showed decreased adhesion due to the reduction of alpha5beta1-fibronectin bonds consequent on the reduction of substrate-bound fibronectin due to the secretion of proteases by v-srcCEF. Excess synthesis of hyaluronic acid by v-srcCEF also reduced the alpha5beta1-fibronectin bonds and contributed to cell detachment at later times in culture. Thus, the adhesion defects were not due to a failure of alpha5beta1 function and adhesion of the v-srcCEF was alpha5beta1 dependent. Integrin-mediated adhesion also produces signals that affect cell proliferation and cell differentiation. An early consequence of these "outside-in" signals was the phosphorylation of FAK Y397 in direct proportion to the number of alpha5beta1-fibronectin bonds formed. In contrast, v-srcCEF had an increased level of phosphorylation on five different tyrosines in FAK, and none of these phosphorylation levels were sensitive to the number of alpha5beta1-fibronectin bonds. In the absence of serum, CEF proliferation was sensitive to changes in alpha5beta1-mediated adhesion levels. Transformation by v-src increased the serum-free proliferation rate and made it insensitive to alpha5beta1-mediated adhesion. Thus, the v-srcCEF were insensitive to the normal outside-in signals from alpha5beta1 integrin.

Glucose rapidly decreases plasma membrane GLUT4 content in rat skeletal muscle

We have previously demonstrated that chronic hyperglycemia per se decreases GLUT4 glucose transporter expression and plasma membrane content in mildly streptozotocin- (STZ) diabetic rats (Biochem. J. 284, 341-348, 1992). In the present study, we investigated the effect of an acute rise in glycemia on muscle GLUT4 and GLUT1 protein contents in the plasma membrane, in the absence of insulin elevation. Four experimental groups of rats were analyzed in the postabsorptive state: 1. Control rats. 2. Hyperglycemic STZ-diabetic rats with moderately reduced fasting insulin levels. 3. STZ-diabetic rats made normoglycemic with phlorizin treatment. 4. Phlorizin-treated (normoglycemic) STZ-diabetic rats infused with glucose for 40 min. The uniqueness of the latter model is that glycemia can be rapidly raised without any concomitant increase in plasma insulin levels. Plasma membranes were isolated from hindlimb muscle and GLUT1 and GLUT4 proteins amounts determined by Western blot analysis. As predicted, STZ-diabetes caused a significant decrease in the abundance of GLUT4 in the isolated plasma membranes. Normalization of glycemia for 3 d with phlorizin treatment restored plasma membrane GLUT4 content in muscle of STZ-diabetic rats. A sudden rise in glycemia over a period of 40 min caused the GLUT4 levels in the plasma membrane fraction to decrease to those of nontreated STZ-diabetic rats. In contrast to the GLUT4 transporter, plasma membrane GLUT1 abundance was not changed by the acute glucose challenge. It is concluded that glucose can have regulatory effect by acutely reducing plasma membrane GLUT4 protein contents in rat skeletal muscle. We hypothesize that this glucose-induced downregulation of plasma membrane GLUT4 could represent a protective mechanism against excessive glucose uptake under hyperglycemic conditions accompanied by insulin resistance.

Labour patterns in Chinese women in Chongqing

OBJECTIVE

To obtain data on the characteristics of labour from a regional sample of Chinese parturients and to assess the pattern of progress of labour among nulliparous women.

DESIGN

A prospective observational study.

SETTING

The study was conducted in the First Affiliated Hospital of Chongqing Medical University.

POPULATION

The final sample involved 1200 Chinese parturients with singleton, vertex and term gestation; spontaneous onset of labour; vaginal delivery; and without adverse perinatal outcomes.

METHODS

A repeated-measures analysis was used to depict labour curves while an interval-censored regression was used to estimate the duration of labour centimetre by centimetre.

MAIN OUTCOME MEASURES

Labour curves and the duration of labour at the 50th and 95th percentiles.

RESULTS

Among 1091 nulliparous women, 57.7% had cervical dilation of 3 cm or less at the time of admission, and the mean duration of the first stage of labour was 9.1 ± 3.3 hours. From 5 to 9 cm of cervical dilation it sometimes took more than 2 hours for dilation to advance 1 cm. No obvious inflection points appeared in the labour curve of Chinese nulliparae, and no deceleration was observed.

CONCLUSION

Progress of labour in Chinese parturients was more gradual than in their Western counterparts. Obstetric practice standards based on data generated from Western countries may not be appropriate for Chinese women.

TWEETABLE ABSTRACT

A prospective study has evaluated labour patterns in Chinese women using regional data from nulliparae.

Density-driven segregation in vertically vibrated binary granular mixtures

Segregation in vertically vibrated binary granular mixtures with the same size is studied experimentally. The partially segregated state occurring in this system is observed carefully. We find that the characteristic of the partially segregated state is that the lighter particles tend to rise and form a pure layer on the top of the system while the heavier particles and some of the lighter ones stay at the bottom and form a mixed layer. The ratio of the thickness of the pure top layer to that of the whole system can be taken as an order parameter, which describes the degree of the segregation quantitatively and is useful in the investigation of the system. By use of it, we find that the segregation state is only dependent on the density ratio of the two kinds of particles. The dependent of the segregation on the vibration frequency is also studied by use of this order parameter, and finally, two typical phase diagrams are given.

Expression modulation of multiple cytokines in vivo by cyanobacteria blooms extract from taihu lake, China

Cyanobacterial blooms that generate microcystins (MCs) are being increasingly recognized as a potent health hazard in aquatic ecosystems. However, immunomodulation induced by cyanotoxins has not been well documented. This paper reports the in vivo data on the immune disorder caused by crude microcystin (MC) extract of cyanobacteria blooms collected from Taihu Lake, China, with respect to cytokine mRNA levels. Using reverse-transcriptional polymerase chain reaction (RT-PCR), the expression of multiple cytokines, including proinflammatory (IL-1beta, TNF-alpha, and IL-6) and Th1/Th2-related cytokines (IL-2, IL-4 and IL-10), was evaluated following the cyanobacteria blooms extract containing MCs (CBE) exposure at four doses of 23, 38, 77, 115 mg lyophilized algae cells/kg body weight. The results showed that the mRNA levels of TNF-alpha, IL-1beta, IL-2 and IL-4 decreased significantly following injection of all doses as compared to the control (LPS or ConA only), while the IL-6 level was unaffected. Contrast to this decrease, the level of IL-10 mRNA was, however, transiently up regulated following injection of the lowest dose of CBE. The distinct patterns of expression of these cytokines suggested a modulation of cytokine network, the essential component of the host immune system. We further developed a mathematical model to simulate the interaction of T helper cell subsets and related cytokines, which proved to be a good approach to study the kinetics of the interaction of cells and cytokines in microcystin immunosuppression.

Acidic cellular microenvironment modifies carcinogen-induced DNA damage and repair

Chronic inflammation creates an acidic microenvironment, which plays an important role in cancer development. To investigate how low pH changes the cellular response to the carcinogen benzo[a]pyrene (B[a]P), we incubated human pulmonary epithelial cells (A549 and BEAS-2B) with nontoxic doses of B[a]P using culturing media of various pH’s (extracellular pH (pH_e) of 7.8, 7.0, 6.5, 6.0 and 5.5) for 6, 24 and 48 h. In most incubations (pH_e 7.0–6.5), the pH in the medium returned to the physiological pH 7.8 after 48 h, but at the lowest pH (pH_e < 6.0), this recovery was incomplete. Similar changes were observed for the intracellular pH (pH_i). We observed that acidic conditions delayed B[a]P metabolism and at t = 48 h, and the concentration of unmetabolized extracellular B[a]P and B[a]P-7,8-diol was significantly higher in acidic samples than under normal physiological conditions (pH_e 7.8) for both cell lines. Cytochrome P450 (CYP1A1/CYP1B1) expression and its activity (ethoxyresorufin-O-deethylase activity) were repressed at low pH_e after 6 and 24 h, but were significantly higher at t = 48 h. In addition, a DNA repair assay showed that the incision activity was ~80% inhibited for 6 h at low pH_e and concomitant exposure to B[a]P. However, at t = 48 h, the incision activity recovered to more than 100% of the initial activity observed at neutral pH_e. After 48 h, higher B[a]P-DNA adduct levels and γ-H2AX foci were observed at low pH samples than at pH_e 7.8. In conclusion, acidic pH delayed the metabolism of B[a]P and inhibited DNA repair, ultimately leading to increased B[a]P-induced DNA damage.

Intravascular recovery of VWF and FVIII following intraperitoneal injection and differences from intravenous and subcutaneous injection in mice

Intravenous infusion studies in humans suggest that both von Willebrand factor (VWF) and factor VIII (FVIII) remain intravascular in contrast to other coagulation proteins. We explored whether infusion of VWF and FVIII by either intraperitoneal (i.p.) or subcutaneous (s.c.) injection would result in efficient absorption of these large proteins into the vascular circulation. FVIII(null) or VWF(null) mice were infused with plasma-derived or recombinant VWF and/or FVIII by i.p., s.c., or intravenous (i.v.) injection. Both VWF and FVIII were absorbed into the blood circulation after i.p. injection with a peak between 2 and 4 h at levels similar to those observed in mice infused intravenously. In contrast, neither VWF nor FVIII was detected in the plasma following s.c. injection. Although i.v. injection achieved peak plasma levels quickly, both human VWF and FVIII rapidly decreased during the first 2 h following i.v. injection. Following both i.v. and i.p. infusion of VWF, the multimeric structure of circulating VWF was similar to that observed in the infusate. These results demonstrate that both VWF and FVIII can be efficiently absorbed into the blood circulation following i.p., but not s.c. injection, indicating that i.p. administration could be an alternative route for VWF or FVIII infusion.

Taxonomy of the Streptomyces strain ZG0656 that produces acarviostatin alpha-amylase inhibitors and analysis of their effects on blood glucose levels in mammalian systems

AIMS

To clarify the taxonomic status of strain ZG0656 and analyse the effects of its acarviostatin products on blood glucose levels in mammalian systems.

METHODS AND RESULTS

Our program to screen for new alpha-amylase inhibitors led to the isolation of strain ZG0656. The polyphasic taxonomic study revealed that strain ZG0656 represents a novel variation of Streptomyces coelicoflavus, for which we propose the name S. coelicoflavus var. nankaiensis. Four chemically distinct alpha-amylase inhibitors, acarviostatins I03, II03, III03 and IV03, were isolated from strain ZG0656. Acarviostatins III03 and IV03 are both novel oligomers. All four acarviostatins are mixed noncompetitive porcine pancreas alpha-amylase inhibitors. Acarviostatin III03 is the most potent alpha-amylase inhibitor known to date. Moreover, in the in vitro and in vivo experiments, acarviostatins III03 showed significant inhibition of starch hydrolysis and glucose transfer to blood.

CONCLUSIONS

Strain ZG0656 is a novel variation of S. coelicoflavus, whose products are novel effective alpha-amylase inhibitors. Among the products, acarviostatins III03 could significantly depress blood glucose levels in mammalian systems and be developed towards a possible therapeutic agent for diabetes.

SIGNIFICANCE AND IMPACT OF THE STUDY

Acarviostatin III03 is the most potent alpha-amylase inhibitor known to date. The oligomer will benefit the research on the relationship between alpha-amylase and various inhibitors and will offer more choices in diabetes treatments.

Modulation of IL-1beta, IL-6, TNF-alpha and PGE(2) by pharmacological agents in explants of membranes from failed total hip replacement

Introduction and goal Proinflammatory cytokines and prostaglandin E(2) (PGE(2)) play an important role in the pathophysiology of osteolysis and implant loosening. The aim of this study was to evaluate the role of pharmacological agents in the inhibition of Interleukin-1 (IL-1), interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha) and PGE(2) in explants of interface membranes from failed total hip replacements (fTHR). Material and methods Membranes from fTHR were retrieved (N=20) and explants were incubated for 72h in the absence or presence of tenidap at three different concentrations (5, 20 or 50 microg/ml) or diclofenac (125 microg/l). IL-1beta, IL-6, TNF-alpha, and PGE(2) levels were measured in the culture medium using ELISA Capture or EIA kits. Statistical analysis was done using the Mann-Whitney U-test. Results A statistically significant inhibition in IL-1beta synthesis was found at tenidap concentrations of 20 microg/ml (71.3%, P< 0.05) and 50 microg/ml (79.3%,P< 0.02). Tenidap reduced IL-6 levels by 90.4% at 20 microg/ml (P< 0.005) and 96.0% (P< 0.05) at 50 microg/ml. Tenidap also reduced the synthesis of TNF-alpha by 66.9% (P< 0.05) and 77.4% at concentrations of 20 microg/ml and 50 microg/ml. Tenidap had a marked suppressive effect of over 90% (P< 0.0001) on PGE(2) synthesis in all three concentrations. Diclofenac (125 microg/l) decreased PGE(2) production by 95% (P< 0.0001), but had no significant effect in IL-1beta, IL-6, and TNF-alpha levels in the culture medium. Conclusion The ability to simultaneously suppress the release of proinflammatory cytokines and PGE(2) may help control osteolysis and prevent aseptic loosening of THR. This effect could increase implant longevity and lead the way to the pharmacological treatment of this pathology.

Apparent blood stream origin of endothelial and smooth muscle cells in the neointima of long, impervious carotid-femoral grafts in the dog

The purpose of this study was to determine whether endothelial and smooth muscle cells originating from the blood stream contribute to the endothelialization of impervious, small-caliber, long Dacron grafts used as extraanatomical bypasses in dogs. We implanted silicone-rubber-coated, permanently impervious grafts 64 to 77 cm long and 6 mm in diameter, made of externally supported knitted Dacron as unilateral carotid-femoral bypasses with distal femoral arteriovenous fistulae in 10 dogs for 3 months; sides were alternated between cases. Subjects received 162 mg/day of aspirin, and its effectiveness on platelet aggregation (PA) was evaluated and expressed as a PA score. Graft healing was studied by stereomicroscopy with silver nitrate staining, by light microscopy with hematoxylin-eosin and immunocytochemical staining for endothelial and smooth muscle cells, and by scanning and transmission electron microscopy. Five grafts were patent for 3 months and could be included in the healing study; the five occluded grafts thrombosed within 14 days. Although there was no transinterstitial tissue ingrowth from perigraft tissues into the impervious Dacron grafts, scattered islands of endothelial cells were conclusively demonstrated on graft flow surfaces 3 months after implantation. Average endothelial-like cell coverage of the flow surfaces was 15.6% +/- 3.8%, and alpha-actin-positive smooth muscle cells and microvessels were found beneath some of the endothelial islands. These findings suggest that blood stream-derived endothelial and smooth muscle cells play a role in the healing of the inner wall of Dacron grafts in the dog.

Cerebrovascular disease among patients from the Indian subcontinent

In this study, the authors document the characteristics of South Asian (SA) cerebrovascular patients. A retrospective medical record review comparing SA (n = 99) and European-American (n = 106) patients was performed. SA patients were younger and had a greater prevalence of diabetes, but lower prevalences of hyperlipidemia and tobacco use. SA patients experienced a 75% lower risk of cardiogenic infarctions, but a threefold increased risk of intracranial atherothrombosis. Risk factor modifications and secondary prevention strategies may differ for SA patients.

Identification of central sites involved in butorphanol-induced feeding in rats

Butorphanol (BT), a mixed kappa- and mu-opioid receptor agonist, induces vigorous food intake in rats. Peripheral injection of BT seems to increase food intake more effectively than intracerebroventricular administration. To further elucidate the nature of BT's influence on consummatory behavior, we examined which feeding-related brain areas exhibit increased c-Fos immunoreactivity (IR) following subcutaneous injection of 4 mg/kg body weight BT, a dose known to induce a maximal orexigenic response. We also evaluated whether direct administration of BT into the forebrain regions activated by peripheral BT injection affects food intake. Peripheral BT administration induced c-Fos-IR in the hypothalamic paraventricular nucleus (PVN), central nucleus of the amygdala (CeA), and nucleus of the solitary tract (NTS). However, 0.1-30 microg BT infused into the CeA, failed to increase food intake 1, 2, and 4 h after injection. Only the highest dose of BT (30 microg) injected into the PVN increased feeding. These results suggest that the PVN, CeA, and NTS mediate the effects of peripherally-injected BT. The PVN or CeA are probably not the main target sites of immediate BT action.

Effect of skeletonizing dissection on the internal thoracic artery

BACKGROUND

Skeletonization of the internal thoracic artery (ITA) produces greater length for coronary bypass grafting. We studied the effect of skeletonization on the morphology, histology, and tissue viability of the ITA wall.

METHODS

Six mongrel dogs underwent unilateral ITA dissection; the contralateral ITA was the control. Study periods were 3 weeks (n=3) and 12 weeks (n=3). At sacrifice, the entire anterior chest wall was removed and dynamically fixed with formalin. Extensive histologic comparisons were performed on three tissue blocks taken from each ITA, 2, 8, and 24 cm from their origin.

RESULTS

Flows at the end of the study were comparable to measurements taken during operation, immediately after skeletonization. Grossly, the ITA wall was not injured by skeletonization and there was no adventitial hematoma or bleeding from the sealed branch ends. Microscopic observations showed intact, normal wall structures. Histologic data showed no major significant difference between controls and skeletonized ITAs.

CONCLUSIONS

Careful skeletonizing dissection is not detrimental to the integrity of ITAs, which justifies their use for myocardial revascularization.

Hemodynamic effects of periodic obstructive apneas in sedated pigs with congestive heart failure

Because of similar physiological changes such as increased left ventricular (LV) afterload and sympathetic tone, an exaggerated depression in cardiac output (CO) could be expected in patients with coexisting obstructive sleep apnea and congestive heart failure (CHF). To determine cardiovascular effects and mechanisms of periodic obstructive apnea in the presence of CHF, 11 sedated and chronically instrumented pigs with CHF (rapid pacing) were tested with upper airway occlusion under room air breathing (RA), O(2) breathing (O2), and room air breathing after hexamethonium (Hex). All conditions led to large negative swings in intrathoracic pressure (-30 to -39 Torr) and hypercapnia (PCO(2) approximately 60 Torr), and RA and Hex also caused hypoxia (to approximately 42 Torr). Relative to baseline, RA increased mean arterial pressure (from 97.5 +/- 5.0 to 107.3 +/- 5.7 Torr, P < 0.01), systemic vascular resistance, LV end-diastolic pressure, and LV end-systolic length while it decreased CO (from 2.17 +/- 0.27 to 1.52 +/- 0.31 l/min, P < 0.01), stroke volume (SV; from 23.5 +/- 2.4 to 16.0 +/- 4.0 ml, P < 0.01), and LV end-diastolic length (LVEDL). O2 and Hex decreased mean arterial pressure [from 102.3 +/- 4.1 to 16.0 +/- 4.0 Torr (P < 0.01) with O2 and from 86.0 +/- 8.5 to 78.1 +/- 8.7 Torr (P < 0.05) with Hex] and blunted the reduction in CO [from 2.09 +/- 0.15 to 1.78 +/- 0.18 l/ml for O2 and from 2.91 +/- 0.43 to 2.50 +/- 0.35 l/ml for Hex (both P < 0.05)] and SV. However, the reduction in LVEDL and LV end-diastolic pressure was the same as with RA. There was no change in systemic vascular resistance and LVEDL during O2 and Hex relative to baseline. In the CHF pigs during apnea, there was an exaggerated reduction in CO and SV relative to our previously published data from normal sedated pigs under similar conditions. The primary difference between CHF (present study) and the normal animals is that, in addition to increased LV afterload, there was a decrease in LV preload in CHF contributing to SV depression not seen in normal animals. The decrease in LV preload during apneas in CHF may be related to effects of ventricular interdependence.