Feasibility of prophylactic laparoscopic appendectomy in obese patients

PURPOSE

To investigate the feasibility of prophylactic laparoscopic appendectomy in obese patients.

MATERIALS AND METHODS

A retrospective study was performed in obese patients undergoing total laparoscopic hysterectomy (TLH) along (66 patients, TLH group) or in combination (55 patients, THL+LA group) with laparoscopic appendectomy (LA) between 2007 and 2012. Operation time, intraoperative bleeding volume, postoperative exhaust time, analgesic use, and the incidence of major complications, hospital stay and cost of hospitalization were compared.

RESULTS

The operation time was longer in THL+LA group than in TLH group (p < 0.05), while the intraoperative bleeding volume, postoperative exhaust time, postoperative morbidity, the incidence of major postoperative complications, and hospitalization time were not significantly different between the two groups.

CONCLUSION

It is safe and feasible for obese patients to undergo simultaneous LA and prophylactic appendectomy, and the combined procedure does not increase the risk of infection of hysterectomy and avoids reoperation of patients due to the recurrence of appendicitis.

Kaempferol Promotes Transplant Tolerance by Sustaining CD4+FoxP3+ Regulatory T Cells in the Presence of Calcineurin Inhibitor

Calcineurin inhibitor cyclosporine is widely used as an immunosuppressant in clinic. However, mounting evidence has shown that cyclosporine hinders tolerance induction by dampening Tregs. Therefore, it is of paramount importance to overcome this pitfall. Kaempferol was reported to inhibit DC function. Here, we found that kaempferol delayed islet allograft rejection. Combination of kaempferol and low-dose, but not high-dose, of cyclosporine induced allograft tolerance in majority of recipient mice. Although kaempferol plus either dose of cyclosporine largely abrogated proliferation of graft-infiltrating T cells and their CTL activity, both proliferation and CTL activity in mice treated with kaempferol plus low-dose, but not high-dose, cyclosporine reemerged rapidly upon treatment withdrawal. Kaempferol increased CD4+FoxP3+ Tregs both in transplanted mice and in vitro, likely by suppressing DC maturation and their IL-6 expression. Reduction in Tregs by low dose of cyclosporine was reversed by kaempferol. Kaempferol-induced Tregs exhibited both allospecific and non-allospecific suppression. Administering IL-6 abrogated allograft tolerance induced by kaempferol and cyclosporine via diminishing CD4+FoxP3+ Tregs. Thus, for the first time, we demonstrated that kaempferol promotes transplant tolerance in the presence of low dose of cyclosporine, which allows for sufficient Treg generation while minimizing side effects, resulting in much-needed synergy between kaempferol and cyclosporine.

Molecular genotyping of Mycobacterium tuberculosis in Xi'an, China, using MIRU-VNTR typing

SETTING

The molecular genotyping of Mycobacterium tuberculosis is expected to lead to a better understanding of M. tuberculosis transmission in Xi'an, one of the largest cities in Western China.

OBJECTIVE

To characterize the population of M. tuberculosis strains circulating in Xi'an and to evaluate the feasibility of the mycobacterial interspersed repetitive units-variable number of tandem repeats (MIRU-VNTR) typing method.

DESIGN

A total of 195 M. tuberculosis clinical isolates from Xi'an were genotyped using spoligotyping and MIRU-VNTR.

RESULTS

Thirty-two different genotypes were identified by spoligotyping, with the Beijing family identified as the largest lineage (84.6%), followed by the T1 (3.08%), T2 (1.54%), H3 (1.03%) and U (1.03%) families. The Hunter-Gaston discriminatory index (HGDI) of spoligotyping is low (HGDI = 0.392). In contrast, 15-locus MIRU-VNTR shows a higher discriminatory power (HGDI = 0.998) than 12-locus MIRU-VNTR (HGDI = 0.948). By replacing the ETR C locus with the MIRU39 locus, the discriminatory power of 15-locus MIRU-VNTR is increased to 0.999.

CONCLUSIONS

The Beijing family accounts for the vast majority of M. tuberculosis isolates in Xi'an, China. The modified 15-locus MIRU-VNTR showed high HGDI and can be used as a first-line genotyping method in combination with spoligotyping in routine epidemiological investigations in Xi'an, China.

Effects of environmental parameters and irrigation on the turgor pressure of banana plants measured using the non-invasive, online monitoring leaf patch clamp pressure probe

Turgor pressure provides a sensitive indicator for irrigation scheduling. Leaf turgor pressure of Musa acuminate was measured by using the so-called leaf patch clamp pressure probe, i.e. by application of an external, magnetically generated and constantly retained clamp pressure to a leaf patch and determination of the attenuated output pressure P(p) that is highly correlated with the turgor pressure. Real-time recording of P(p) values was made using wireless telemetric transmitters, which send the data to a receiver base station where data are logged and transferred to a GPRS modem linked to an Internet server. Probes functioned over several months under field and laboratory conditions without damage to the leaf patch. Measurements showed that the magnetic-based probe could monitor very sensitively changes in turgor pressure induced by changes in microclimate (temperature, relative humidity, irradiation and wind) and irrigation. Irrigation effects could clearly be distinguished from environmental effects. Interestingly, oscillations in stomatal aperture, which occurred frequently below turgor pressures of 100 kPa towards noon at high transpiration or at high wind speed, were reflected in the P(p) values. The period of pressure oscillations was comparable with the period of oscillations in transpiration and photosynthesis. Multiple probe readings on individual leaves and/or on several leaves over the entire height of the plants further emphasised the great impact of this non-invasive turgor pressure sensor system for elucidating the dynamics of short- and long-distance water transport in higher plants.

Organization of NMDA receptors at extrasynaptic locations

NMDA receptors are found in neurons both at synapses and in extrasynaptic locations. Extrasynaptic locations are poorly characterized. Here we used preembedding immunoperoxidase and postembedding immunogold electron microscopy and fluorescence light microscopy to characterize extrasynaptic NMDA receptor locations in dissociated hippocampal neurons in vitro and in the adult and postnatal hippocampus in vivo. We found that extrasynaptic NMDA receptors on neurons in vivo and in vitro were usually concentrated at points of contact with adjacent processes, which were mainly axons, axon terminals, or glia. Many of these contacts were shown to contain adhesion factors such as cadherin and catenin. We also found associations of extrasynaptic NMDA receptors with the membrane associated guanylate kinase (MAGUKs), postsynaptic density (PSD)-95 and SAP102. Developmental differences were also observed. At postnatal day 2 in vivo, extrasynaptic NMDA receptors could often be found at sites with distinct densities whereas dense material was seen only rarely at sites of extrasynaptic NMDA receptors in the adult hippocampus in vivo. This difference probably indicates that many sites of extrasynaptic NMDA receptors in early postnatal ages represent synapse formation or possibly sites for synapse elimination. At all ages, as suggested in both in vivo and in vitro studies, extrasynaptic NMDA receptors on dendrites or the sides of spines may form complexes with other proteins, in many cases, at stable associations with adjacent cell processes. These associations may facilitate unique functions for extrasynaptic NMDA receptors.

Protective immunity induced by daily bites from irradiated mosquitoes infected with Plasmodium yoelii

Individuals in malaria endemic regions do not develop fully protective immune responses against Plasmodium liver stage infections. In high transmission areas, individuals can be exposed to more than two infective mosquito bites daily. Their exposure to Plasmodium sporozoites, therefore, is in the form of small and frequent doses. This is very different from individuals studied in controlled immunization trials where the delivery of large numbers of radiation-attenuated sporozoites in a limited number of doses can induce sterile protective immunity. Using irradiated mosquitoes infected with Plasmodium yoelii 17XNL, we tested whether daily bites from a few mosquitoes can induce a protective immune response in mice. This immunization strategy successfully induced a protective response, preventing the development of liver stages when mice were challenged with nonirradiated sporozoites. These results provide further support for the development of liver stage vaccines. They are also a call for further study into why fully protective responses against the liver stage are not seen in individuals from endemic regions.

Effects on capacitance by overexpression of membrane proteins

Functional Channelrhodopsin-2 (ChR2) overexpression of about 10(4)channels/mum(2) in the plasma membrane of HEK293 cells was studied by patch-clamp and freeze-fracture electron microscopy. Simultaneous electrorotation measurements revealed that ChR2 expression was accompanied by a marked increase of the area-specific membrane capacitance (C(m)). The C(m) increase apparently resulted partly from an enlargement of the size and/or number of microvilli. This is suggested by a relatively large C(m) of 1.15+/-0.08 microF/cm(2) in ChR2-expressing cells measured under isotonic conditions. This value was much higher than that of the control HEK293 cells (0.79+/-0.02 microF/cm(2)). However, even after complete loss of microvilli under strong hypoosmolar conditions (100 mOsm), the ChR2-expressing cells still exhibited a significantly larger C(m) (0.85+/-0.07 microF/cm(2)) as compared to non-expressing control cells (0.70+/-0.03 microF/cm(2)). Therefore, a second mechanism of capacitance increase may involve changes in the membrane permittivity and/or thickness due to the embedded ChR2 proteins.

A combined patch-clamp and electrorotation study of the voltage- and frequency-dependent membrane capacitance caused by structurally dissimilar lipophilic anions

Interactions of structurally dissimilar anionic compounds with the plasma membrane of HEK293 cells were analyzed by patch clamp and electrorotation. The combined approach provides complementary information on the lipophilicity, preferential affinity of the anions to the inner/outer membrane leaflet, adsorption depth and transmembrane mobility. The anionic species studied here included the well-known lipophilic anions dipicrylamine (DPA⁻), tetraphenylborate (TPB⁻) and [W₂(CO)₁₀(S₂CH)]⁻, the putative lipophilic anion \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ {\text{B}}{\left( {{\text{CF}}_{3} } \right)}^{ - }_{4} $$\end{document} and three new heterocyclic W(CO)₅ derivatives. All tested anions partitioned strongly into the cell membrane, as indicated by the capacitance increase in patch-clamped cells. The capacitance increment exhibited a bell-shaped dependence on membrane voltage. The midpoint potentials of the maximum capacitance increment were negative, indicating the exclusion of lipophilic anions from the outer membrane leaflet. The adsorption depth of the large organic anions DPA⁻, TPB⁻ and \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ {\text{B}}{\left( {{\text{CF}}_{3} } \right)}^{ - }_{4} $$\end{document} increased and that of W(CO)₅ derivatives decreased with increasing concentration of mobile charges. In agreement with the patch-clamp data, electrorotation of cells treated with DPA⁻ and W(CO)₅ derivatives revealed a large dispersion of membrane capacitance in the kilohertz to megahertz range due to the translocation of mobile charges. In contrast, in the presence of TPB⁻ and \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ {\text{B}}{\left( {{\text{CF}}_{3} } \right)}^{ - }_{4} $$\end{document} no mobile charges could be detected by electrorotation, despite their strong membrane adsorption. Our data suggest that the presence of oxygen atoms in the outer molecular shell is an important factor for the fast translocation ability of lipophilic anions.

441. Renin angiotensin system polymorphisms are associated with pregnancy complications

Preeclampsia (PE), small for gestational age (SGA) and preterm birth (PTB) together affect 20% of first pregnancies. Currently there is no reliable way to identify women at risk. Polymorphims in genes in the renin angiotensin system (RAS) may be associated with impaired placentation and poor maternal response to pregnancy and hence predict risk for pregnancy complications. We aimed to determine if three functional polymorphisms in RAS genes, namely, AGT M235T, ACE (I/D) and AT1R A1166C are associated with pregnancy complications. Pregnancy trios were prospectively recruited from two public hospitals in Adelaide. Pregnancies were classified into normal (n = 110), PE (n = 26), SGA (n = 47), PE+SGA (n = 12), gestational hypertension (GH, n = 17), PTB (n = 20). PE, PE +SGA and GH were also grouped together as hypertension. Parental blood and maternal blood pressure was sampled or measured at 15 weeks gestation. Cord blood was sampled after delivery. DNA was extracted from buffy coats and genotyped using high resolution melt analyses. Maternal plasma [ACE] was measured by ELISA. Data were analysed by ANOVA and Fisher's exact test. Likelihood ratios (LR) were calculated where appropriate. Maternal ACE I/D was associated with hypertension (P = 0.001, LR = 14.8) and SGA (P = 0.019, LR = 10). Paternal AT1R A1166C was associated with PTB (P = 0.01, LR = 7.4). For ACE I/D, plasma [ACE] in women with DD was 33% and 62% higher than ID and II, respectively (both P < 0.001). Systolic blood pressure in women with DD was 6% higher than II (P = 0.04). Our data suggest that RAS polymorphisms are associated with pregnancy complications. Furthermore, maternal ACE genotype determines plasma [ACE] and affects blood pressure at 15 weeks gestation, well before symptoms manifest. Our data also suggest that paternal genotype may be important in determining risk for pregnancy complications, consistent with the role of paternity in their aetiology.

Role of 2-5A-dependent RNase-L in senescence and longevity

Senescence is a permanent growth arrest that restricts the lifespan of primary cells in culture, and represents an in vitro model for aging. Senescence functions as a tumor suppressor mechanism that can be induced independent of replicative crisis by diverse stress stimuli. RNase-L mediates antiproliferative activities and functions as a tumor suppressor in prostate cancer, therefore, we examined a role for RNase-L in cellular senescence and aging. Ectopic expression of RNase-L induced a senescent morphology, a decrease in DNA synthesis, an increase in senescence-associated beta-galactosidase activity, and accelerated replicative senescence. In contrast, senescence was retarded in RNase-L-null fibroblasts compared with wild-type fibroblasts. Activation of endogenous RNase-L by 2-5A transfection induced distinct senescent and apoptotic responses in parental and Simian virus 40-transformed WI38 fibroblasts, respectively, demonstrating cell type specific differences in the antiproliferative response to RNase-L activation. Replicative senescence is a model for in vivo aging; therefore, genetic disruption of senescence effectors may impact lifespan. RNase-L-/- mice survived 31.7% (P<0.0001) longer than strain-matched RNase-L+/+ mice providing evidence for a physiological role for RNase-L in aging. These findings identify a novel role for RNase-L in senescence that may contribute to its tumor suppressive function and to the enhanced longevity of RNase-L-/- mice.

Biophysical characterisation of electrofused giant HEK293-cells as a novel electrophysiological expression system

Giant HEK293 cells of 30-65 microm in diameter were produced by three-dimensional multi-cell electrofusion in 75 mOsm sorbitol media. These strong hypotonic conditions facilitated fusion because of the spherical shape and smooth membrane surface of the swollen cells. A regulatory volume decrease (RVD), as observed at higher osmolalities, did not occur at 75 mOsm. In contrast to field-treated, but unfused cells, the increase in volume induced by hypotonic shock was only partly reversible in the case of fused giant cells after their transfer into isotonic medium. The large size of the electrofused cells allowed the study of their electrophysiological properties by application of both whole-cell and giant excised patch-clamp techniques. Recordings on giant cells yielded a value of 1.1+/-0.1 microF/cm2 for the area-specific membrane capacitance. This value was consistent with that of the parental cells. The area-specific conductivity of giant cells (diameter > 50 microm) was found to be between 12.8 and 16.1 microS/cm2, which is in the range of that of the parental cells. Measurements with patch-pipettes containing fluorescein showed uniform dye uptake in the whole-cell configuration, but not in the cell-attached configuration. The diffusion-controlled uniform uptake of the dye into the cell interior excludes internal compartmentalisation. The finding of a homogeneous fusion was also supported by expression of the yellow fluorescent protein YFP (as part of the fusion-protein ChR2-YFP) in giant cells since no plasma-membrane bound YFP-mediated fluorescence was detected in the interior of the electrofused cells. Functional expression and the electrophysiological characterisation of the light-activated cation channel Channelrhodopsin 2 (ChR2) yielded similar results as for parental cells. Most importantly, the giant cells exhibited a comparable expression density of the channel protein in the plasma membrane as observed in parental cells. This demonstrates that electrofused cells can be used as a heterologous expression system.

Molecular pathology of X linked retinoschisis: mutations interfere with retinoschisin secretion and oligomerisation

BACKGROUND/AIM

X linked retinoschisis (XLRS) is caused by mutations in RS1 which encodes the discoidin domain protein retinoschisin, secreted by photoreceptors and bipolar cells. Missense mutations occur throughout the gene and some of these are known to interfere with protein secretion. This study was designed to investigate the functional consequences of missense mutations at different locations in retinoschisin.

METHODS AND RESULTS

The authors developed a structural model of the retinoschisin discoidin domain and used this to predict the effects of missense mutations. They expressed disease associated mutations and found that those affecting conserved residues prevented retinoschisin secretion. Most of the remaining mutations cluster within a series of loops on the surface of the beta barrel structure and do not interfere with secretion, suggesting this region may be a ligand binding site. They also demonstrated that wild type retinoschisin octamerises and associates with the cell surface. A subgroup of secreted mutations reduce oligomerisation (C59S, C219G, C223R).

CONCLUSIONS

It is suggested that there are three different molecular mechanisms which lead to XLRS: mutations interfering with secretion, mutations interfering with oligomerisation, and mutations that allow secretion and oligomerisation but interfere with retinoschisin function. The authors conclude that binding of oligomerised retinoschisin at the cell surface is important in its presumed role in cell adhesion.

Charge translocation during cosubstrate binding in the Na+/proline transporter of E.coli

Charge translocation associated with the activity of the Na(+)/proline cotransporter PutP of Escherichia coli was analyzed for the first time. Using a rapid solution exchange technique combined with a solid-supported membrane (SSM), it was demonstrated that Na(+)and/or proline individually or together induce a displacement of charge. This was assigned to an electrogenic Na(+)and/or proline binding process at the cytoplasmic face of the enzyme with a rate constant of k>50s(-1) which preceeds the rate-limiting step. Based on the kinetic analysis of our electrical signals, the following characteristics are proposed for substrate binding in PutP. (1) Substrate binding is electrogenic not only for Na(+), but also for the uncharged cosubstrate proline. The charge displacement associated with the binding of both substrates is of comparable size and independent of the presence of the respective cosubstrate. (2) Both substrates can bind individually to the transporter. Under physiological conditions, an ordered binding mechanism prevails, while at sufficiently high concentrations, each substrate can bind in the absence of the other. (3) Both substrate binding sites interact cooperatively with each other by increasing the affinity and/or the speed of binding of the respective cosubstrate. (4) Proline binding proceeds in a two-step process: low affinity (approximately 1mM) electroneutral substrate binding followed by a nearly irreversible electrogenic conformational transition.

Latent antithrombin and its detection, formation and turnover in the circulation

It is now apparent that the inactivated latent and cleaved conformers of antithrombin (AT) are of pathological significance. Using a single-run electrophoretic technique that allows the quantitative assessment of these conformers in 2 microL plasma, we show that near 3% of the total AT in the circulations of normal individuals is in latent conformation. Only trace amounts of cleaved AT were observed. The slow decline in AT activity on incubation of plasma at 37 degrees C was shown to be almost wholly due to a transition of native AT to its inactive latent form. Also initial studies in the rabbit indicate that the latent form, like the cleaved, has an identical circulatory half-life to that of native AT. We deduce that the steady concentration of latent AT in the circulation is due to the transition of some 10(12) molecules of AT per second balanced by an equivalent clearance of the latent form. Examples of clinical applications of the new technique include its use as a comprehensive single-step screen for genetic variants associated with AT deficiency, and notably the potential it provides to monitor the changes responsible for the loss of AT in the shock syndromes.

Gravidity-dependent production of antibodies that inhibit binding of Plasmodium falciparum-infected erythrocytes to placental chondroitin sulfate proteoglycan during pregnancy

During pregnancy, Plasmodium falciparum-infected erythrocytes sequester in the placenta by adhering to chondroitin 4-sulfate, creating a risk factor for both the mother and the fetus. The primigravidae are at higher risk for placental malaria than the multigravidae. This difference in susceptibility has been attributed to the lack of antibodies that block the adhesion of infected erythrocytes to placental chondroitin 4-sulfate in primigravid women. However, recent results show that many primigravidae at term have antibody levels similar to those of multigravidae, and thus the significance of antiadhesion antibodies in providing protection against malaria during pregnancy remains unclear. In this study, we analyzed plasma samples from women of various gravidities at different gestational stages for antiadhesion antibodies. The majority of women, regardless of gravidity, had similar levels of antibodies at term. Most primigravidae had low levels of or no antiadhesion antibodies prior to ~20 weeks of pregnancy and then produced antibodies. Multigravidae also lacked antibodies until ~12 weeks of pregnancy, but thereafter they efficiently produced antibodies. In pregnant women who had placental infection at term, higher levels of antiadhesion antibodies correlated with lower levels of placental parasitemia. The difference in kinetics of antibody production between primigravidae and multigravidae correlated with the prevalence of malaria in these groups, suggesting that antibodies are produced during pregnancy in response to placental infection. The early onset of efficient antibody response in multigravidae and the delayed production to antibodies in primigravidae appear to account for the gravidity-dependent differential susceptibilities of pregnant women to placental malaria.

Altered expression of the neuropeptide-processing enzyme carboxypeptidase E in the rat brain after global ischemia

Carboxypeptidase E, an exoprotease involved in the processing of bioactive peptides released by a regulated secretory pathway, was identified in a subtractive complementary DNA library derived from an ischemic rat brain by differential screening. In situ hybridization and immunocytochemical analysis showed the presence of carboxypeptidase E messenger RNA and protein in the cerebral cortex, thalamus, striatum, and hippocampus of a healthy rat brain. After 15 minutes of transient global ischemia followed by 8 hours of reperfusion, increased levels of carboxypeptidase E messenger RNA and protein were observed in the hippocampal CA1 and CA3 regions and in the cortex, as detected by Northern and Western blot analyses and in situ hybridization. After extended reperfusion (24 to 72 hours), both carboxypeptidase E messenger RNA and protein levels were decreased. The ischemia-induced changes in carboxypeptidase E expression suggest that this enzyme may play a role in modulating the brain's response to ischemia.

Application of double-impedance system and cyclic voltammetry to study the adsorption of fullerols (C60(OH)n) on biological peptide-adsorbed gold electrode

The adsorption of fullerols (C60(OH)n) on glutathione-adsorbed gold electrode was characterized by using double-impedance system, i.e., electrochemical quartz crystal impedance and electrochemical impedance spectroscopy, and cyclic voltammetry. The time courses of piezoelectric parameters were used to reflect the changes of interfacial physical properties, such as mass, density-viscosity, and dielectric constant, during the adsorptions of peptide and fullerols onto electrode. The electrochemical impedance based on the simple equivalent electric network were also simultaneously measured and provided electrochemical interface information, e.g., double-layer capacitance and charge-transfer resistance. It was found that the double-impedance responses were varied with the forms of glutathione. It was also shown that the frequency curves due to the adsorption of oxidized (GSSG) and reduced (GSH) glutathione could be exhibited as different kinetic equations. The heterogeneous charge-transfer rate constants of ferricyanide/ferrocyanide before and after the peptide and fullerols adsorption were determined by CV and EIS methods. The results showed that the proposed method has potential applications in interfacial studies of biomaterials, since these combined techniques have advantages in real time providing multidimensional piezoelectric and electrochemical impedance information.

The role of hypertension-related gene in aortic vascular smooth muscle cells from mice and rats

OBJECTIVE

To study the role of hypertension-related gene (HRG-1) in cardiovascular disease.

METHODS

The expression of HRG-1 was analyzed with RT-PCR and Northern blotting. Vascular smooth muscle cell (VSMC) proliferation was measured with 3H-TdR incorporation and was confirmed with histological analysis.

RESULTS

Northern blot analysis showed that HRG-1 mRNA was expressed not only in VSMC, but also in various rat tissues (heart, brain, lung, kidney, and liver). In addition, the expression of HRG-1 mRNA in heart, brain, kidney and liver of spontaneously hypertensive rat (SHR) was lower than that in the same tissues of Wistar-Kyotorat (WKY). Semi-quantitative RT-PCR and histological analysis showed that the expression of HRG-1 mRNA in ApoE-knockout mice and in animal models of restenosis was decreased and neointimal formation was observed in both models. ET, AII, and IL-1 stimulating VSMC proliferation reduced the expression of HRG-1 mRNA of VSMC. Atrial natriuretic factor (ANF), calcitonin gene-related peptide and adrenomedullin, inhibited VSMC proliferation and elevated the expression of HRG-1 mRNA. These effects could be blocked or attenuated by their corresponding antagonists or antibodies.

CONCLUSION

HRG-1 is a gene related to VSMC proliferation. It may play an important role in several occlusive cardiovascular diseases including atherosclerosis, restenosis and hypertension.

The serpin inhibitory mechanism is critically dependent on the length of the reactive center loop

The recent crystallographic structure of a serpin-protease complex revealed that protease inactivation results from a disruption of the catalytic site architecture caused by the displacement of the catalytic serine. We hypothesize that inhibition depends on the length of the N-terminal portion of the reactive center loop, to which the active serine is covalently attached. To test this, alpha(1)-antitrypsin Pittsburgh variants were prepared with lengthened and shortened reactive center loops. The rates of inhibition of factor Xa and of complex dissociation were measured. The addition of one residue reduced the stability of the complex more than 200,000-fold, and the addition of two residues reduced it by more than 1,000,000-fold, whereas the deletion of one or two residues lowered the efficiency of inhibition and increased the stability of the complex (2-fold). The deletion of more than two residues completely converted the serpin into a substrate. Similar results were obtained for the alpha(1)-antitrypsin variants with thrombin and for PAI-1 and PAI-2 with their common target tissue plasminogen activator. We conclude that the length of the serpin reactive center loop is critical for its mechanism of inhibition and is precisely regulated to balance the efficiency of inhibition and stability of the final complex.

The conformational basis of thrombosis

Antithrombin readily undergoes a spontaneous transition from its active five-stranded form to a six-stranded inactive latent form. The recognition of this change in plasma has been obscured by the immediate linkage of newly formed latent antithrombin to a molecule of active antithrombin to give a dimer with an electrophoretic mobility readily confused with that of native active antithrombin. A new micromethod now allows unequivocal identification of latent antithrombin in whole plasma. This shows that at 37 degrees C some 10% of plasma antithrombin is converted to the latent form in 24 h. The rate of conversion is greatly accelerated at increased temperatures, as occurs in the pasteurisation of plasma concentrates that should now be checked for efficacy. But increased transition also occurs in the plasma at the slightly increased temperatures that accompany incidental infections. This is of particular significance if there is a conformationally unstable variant of antithrombin; here fever can provoke a sudden transition with the onset of a characteristically severe episode of thromboembolism. Such variants are not rare and include those previously classified as pleiotropic. The precise structural pathway, now known with antithrombin, provides a model of the changes occurring in other conformational diseases, including Alzheimer's and the prion dementias.

[Seroepidemiological analysis of characteristic of hepatitis B virus in children after vaccination in Ningbo]

OBJECTIVE

To understand the immunity of children in Ningbo after hepatitis B vaccination for seven years and to explore the best time for booster.

METHODS

One thousand nine hundred and twenty serum samples from children born in 1982 - 1995 were tested for anti-HBs and HBsAg, using RIA.

RESULTS

(1) HBsAg positive rate (2.66%) was lower in vaccinated children born in 1992 - 1995 than those unvaccinated (10.92%) born in 1982 - 1995. HBsAg positive rate had a drop of 75.71% (chi(2) = 22.91, P < 0.0001). (2) Anti-HBs positive rates (65.95%) in vaccinated children was much higher than that in unvaccinated children (41.03%) (chi(2) = 113.67, P < 0.0001). (3) It also showed that children's positive rate of HBsAg increased and anti-HBs dropped after 5 - 7 years of vaccination.

CONCLUSION

After immunization of hepatitis B vaccine for 7 years, high immunity and low infection rate of HB in children it appeared in Ningbo. However it is necessary to further study the reason causing the increase of HBsAg positive rate and/or deerease of anti-HBs positive rate, and the suitable time frame of boostering, after 4 or 5 years of primary vaccination.

Severe defect in proglucagon processing in islet A-cells of prohormone convertase 2 null mice

Mice homozygous for a deletion in the gene encoding prohormone convertase 2 (PC2) are generally healthy but have mild hypoglycemia and flat glucose-tolerance curves. Their islets show marked alpha (A)-cell hyperplasia, suggesting a possible defect in glucagon processing (Furuta, M., Yano, H., Zhou, A., Rouille, Y., Holst, J., Carroll, R., Ravazzola, M., Orci, L., Furuta, H., and Steiner, D. (1997) Proc. Natl. Acad. Sci. U. S. A. 94, 6646-6651). In this report we have examined the biosynthesis and processing of proglucagon in isolated islets from these mice via pulse-chase labeling and find that proglucagon undergoes essentially no processing in chase periods up to 8 h in duration. Only a small percent of cleavage at the sensitive interdomain site (residues 71 and 72) appears to occur. These observations thus conclusively demonstrate the essentiality of PC2 for the production of glucagon in the islet A-cells. Ultrastructural and immunocytochemical studies indicate the presence of large amounts of proglucagon in atypical appearing secretory granules in the hyperplastic and hypertrophic A-cells, along with morphological evidence of high rates of proglucagon secretion in PC2 null islets. These findings provide strong evidence that active glucagon is required to maintain normal blood glucose levels, counterbalancing the action of insulin at all times.

Percutaneous balloon aortic valvuloplasty in the treatment of congenital valvular aortic stenosis in children

OBJECTIVE

To assess the effect of the balloon valvuloplasty for for congenital valvular aortic stenosis (AS) in children.

METHODS

A total of 27 (mean age 6.09 years) children with AS accepted the treatment of percutaneous balloon aortic valvuloplasty (PBAV). The ratios of balloon/valve were 0.95 +/- 0.08 for 19 cases of typical AS and 1.00 +/- 0.11 for 8 cases of hypoplastic AS. The patients were evaluated by the gradients across aortic valves in pre- and post-PBAV and by echocardiogram during the follow-up period.

RESULTS

Fifteen of 19 (78.9%) cases of typical AS had a better outcome and the gradient of the remaining 4 cases (26.7%) had increased after follow-up (delta P > 50 mm Hg). Four of 8 (50.0%) cases of hypoplastic AS had satisfactory responses and the gradient of the remaining 3 cases (75.0%) rose. There was no moderate to severe aortic insufficiency (AI).

CONCLUSION

The balloon aortic valvuloplasty provides safe and significant hemodynamic and clinical improvement in pediatric patients. The outcome of PBAV for typical AS is better than for hypoplastic AS.

Percutaneous balloon angioplasty of coarctation of the aorta in children: 12-year follow-up results

OBJECTIVE

To evaluate the efficiency of percutaneous balloon angioplasty of coarctation of the aorta in children and discuss its risk factors that can lead to poor long-term results.

METHODS

From September 1987 to August 1999, 24 patients underwent 27 balloon angioplasty procedures for native or recurrent coarctation of the aorta at our institution. There were 19 patients with discrete (membranous) coarctation, 4 patients with long-segment and aortic arch hypoplasia, and 1 patient with postoperative recurrence. The balloon diameter was chosen not to exceed the diameter of the aorta proximal to the stenotic site (11.06 +/- 2.80 mm vs 11.78 +/- 3.18 mm), with the chosen diameter two to four times that of the stenotic segment (2.57 +/- 0.68 times). The patients have been followed up for half to twelve years (mean 6.2 +/- 2.8 years). Satisfactory result was defined as a reduction in the pressure gradient across the site of coarctation to < or = 20 mm Hg.

RESULTS

The systolic pressure gradient across the coarctation site decreased from 48.17 +/- 14.68 mm Hg to 14.96 +/- 13.12 mm Hg (P < 0.01) and the diameter of the coarctation site increased from 4.66 +/- 2.43 mm to 8.80 +/- 3.32 mm (P < 0.01). Immediate satisfactory results were obtained in 19 patients (79%). Of the 5 patients with unsatisfactory results, 4 had aortic arch hypoplasia and 1 had membranous coarctation. Of the 19 patients with satisfactory results, 18 patients had membranous coarctation and 1 patient had recurrent postoperative coarctation. No aneurysm and other complications had occurred in any patients at the follow-ups.

CONCLUSION

Percutaneous balloon angioplasty is an effective treatment alternative to surgery in most patients with recurrent postoperative or native membranous coarctation of the aorta. It should not be recommended for the coarctation of aortic arch hypoplasia.

All-trans retinoic acid in pulmonary vascular structural remodeling in rats with pulmonary hypertension induced by monocrotaline

OBJECTIVE

To determine whether all-trans retinoic acid (atRA) exerts an inhibitory effect on rats with pulmonary hypertension induced by monocrotaline.

METHODS

All rats were given a single subcutaneous injection of either monocrotaline (60 mg/kg) or saline. Monocrotaline-injected rats received either atRA (30 mg.kg-1.day-1) or saline through oral-gastro intubation. On Days 7, 14, 21, and 28 respectively after monocrotaline injection, cardiovascular catheters were inserted to examine the mean pulmonary artery pressure of rats in each group. Meanwhile, the matrix metalloproteinase-1 (MMP-1) mRNA expression and hydroxyproline content in the main pulmonary artery were determined by RT-PCR and chromometry, respectively.

RESULTS

The mean pulmonary artery pressure of rats in the model group increased significantly on day 21 and reached a peak on Day 28 compared with the control group (25.7 +/- 4.3 mm Hg vs 15.1 +/- 1.5 mm Hg and 38.5 +/- 6.4 mm Hg vs 16.4 +/- 2.0 mm Hg, P < 0.01). MMP-1 mRNA overexpression was present on Day 14 (0.72 +/- 0.15 vs 0.39 +/- 0.08, P < 0.01) and was rapidly down-regulated on Day 21 and 28 compared with Day 14, but was still higher than that in the control. The hydroxyoroline content of the main pulmonary artery dropped significantly on Day 14 (4.01 +/- 1.13 micrograms/mg vs 5.10 +/- 0.91 micrograms/mg, P < 0.05) and increased significantly on Days 21 and 28 compared with the control. atRA inhibited the MMP-1 mRNA overexpression from Day 14 to Day 28 and reduced the hydroxyproline content (5.59 +/- 0.70 micrograms/mg vs 7.96 +/- 1.13 micrograms/mg and 7.77 +/- 0.96 micrograms/mg vs 9.93 +/- 1.27 micrograms/mg, P < 0.01) and the mean pulmonary artery pressure compared with the model group (19.6 +/- 3.2 mm Hg vs 25.7 +/- 4.3 mm Hg and 26.3 +/- 4.6 mm Hg vs 38.5 +/- 6.4 mm Hg, P < 0.01).

CONCLUSION

atRA inhibits MMP-1 overexpression and the accumulation of collagen, which might elicit favorable geometric remodeling in rat pulmonary hypertension induced by monocrotaline.

Analysis of chromosomal and organellar DNA of somatic hybrids between Triticum aestiuvm and Haynaldia villosa Schur

Intergeneric somatic hybridization between wheat (cv. Jinan 177) protoplasts that have 24-28 chromosomes and Haynaldia villosa protoplasts containing 11-14 chromosomes was carried out by the polyethylene glycol (PEG) method. A high frequency of hybrid calli and plants were obtained from the fusion products, as revealed by cytological and biochemical techniques and by PCR analysis of 5S rDNA spacer sequences. GISH (genomic in situ hybridization) analysis confirmed the presence of chromosomes from both parents in the hybrid clones and the common occurrence of translocations between them. The RFLP analysis of the organellar DNA using mitochondrion- and chloroplast-specific probes revealed that mitochondria from both parents existed in the cells of hybrid calli and their recombination, whereas chloroplasts segregated and recombined randomly. The gross morphology of hybrid plants resembled that of wheat, but the gross morphology of their ovaries and anthers were intermediate between those of the two parents. The relationship between hybrid plant regeneration and the balance of genetic materials in hybrid clones is discussed.

[Inhibitory effect of antisense VEGF₁₂₁ and endostatin genes transfection on tumor growth and metastasis of human giant cell lung cancer]

BACKGROUND

To explore the co-operative inhibitory effect of antisense VEGF gene and endostatin gene transfection on tumor angiogenesis, tumor growth and metastasis of lung cancer.

METHODS

Antisense VEGF₁₂₁ cDNA was transfected into PG cells(PG-AS-VEGF) by lipofectin. After PG-AS-VEGF cells were xenografted to nude mice, PsectagA-endostatin gene was transfected into nude mice by electric pulse mediation. The MVDs in tumors and tumor biological characteristics were observed.

RESULTS

(1)The MVD in PG-AS-VEGF tumor in nude mice was significantly lower than that in PG-vector tumor (PG-AS-VEGF and PG-vector: 40.67±9.35 and 58.34±10.52, respectively) in nude mice. (2)There was no significant difference between the PG-vector tumor and PG-AS-VEGF tumor in early stage of the tumor growth in vivo. However, PG-AS-VEGF tumor grew significantly more slowly than PG-vector tumor after 18 days (P<0.05). (3)PG-AS-VEGF tumor could lead to regional and/or distant lymph node metastases (16.7%, 2/12), which was much more infrequent than that in PG-vector group (50%, 6/12). (4) PG-AS-VEGF tumor growth was remarkably inhibited by endostatin gene transfected at site of the tumor inoculation as compared with the control group in nude mice (P<0.05). (5)The PG-AS-VEGF tumors transfected with the endostatin gene at site of the tumor inoculation(AST) could also produce much lower regional and/or distant lymph node metastases rate (12.5%, 1/8) than that in the PG-AS-VEGF tumor transfected with the PsectagA vector (ASP)(75%, 6/8).

CONCLUSIONS

Endostatin gene transfection could cooperatively inhibit the growth and spontaneous lymph node metastasis of antisense VEGF gene transfected PG cells in nude mice.

Polymerization of plasminogen activator inhibitor-1

The activity of the serine proteinase inhibitor (serpin) plasminogen activator inhibitor-1 (PAI-1) is controlled by the intramolecular incorporation of the reactive loop into beta-sheet A with the generation of an inactive latent species. Other members of the serpin superfamily can be pathologically inactivated by intermolecular linkage between the reactive loop of one molecule and beta-sheet A of a second to form chains of polymers associated with diverse diseases. It has long been believed that PAI-1 is unique among active serpins in that it does not form polymers. We show here that recombinant native and latent PAI-1 spontaneously form polymers in vitro at low pH although with distinctly different electrophoretic patterns of polymerization. The polymers of both the native and latent species differ from the typical loop-A-sheet polymers of other serpins in that they readily dissociate back to their original monomeric form. The findings with PAI-1 are compatible with different mechanisms of linkage, each involving beta-strand addition of the reactive loop to s7A in native PAI-1 and to s1C in latent PAI-1. Glycosylated native and latent PAI-1 can also form polymers under similar conditions, which may be of in vivo importance in the low pH environment of the platelet.

A piezoelectric quartz crystal impedance study on Cu(2+)-induced precipitation of bovine serum albumin in aqueous solution

Piezoelectric quartz crystal impedance (QCI) technique was used for monitoring the Cu(2+)-induced precipitation of bovine serum albumin onto the gold electrode. The critical precipitate concentration of Cu(2+) reflected by the significant decrease in the resonant frequency was estimated to be 9.98 x 10(-5) mol x l(-1), and the saturated adherence of the precipitate on the electrode occurred when the Cu(2+) concentration was greater than 9.79x10(-3) mol x l(-1). The frequency shift in air was about 85.5% of that in liquid, and the Deltaf(0)/DeltaR(1) ratio found in solution was 82.67 Hz Omega(-1), suggesting that the frequency response was predominated by the mass change due to precipitate adherence to the electrode surface. The response of the resonant frequency was analyzed using an equation Deltaf=a(0) + a(1) e(-t/tau(1)) + a(2) e(-t/tau(2)). The relationship between the total a(0) values and the Cu(2+) concentration was discussed.

[Human papilloma virus infection and expression of p16 protein in laryngeal papilloma and laryngeal carcinoma]

OBJECTIVE

To evaluate the role of human papilloma virus (HPV) infection and inactivation of p16 gene in laryngeal papilloma (LP) and laryngeal squamous cell carcinoma (LC).

METHODS

HPV consensus primers direct in situ polymerase chain reaction (ISPCR) and immunohistochemical method were applied to detect the presence of HPV genomes (1, 6, 8, 11, 13, 16, 18, 30, 31, 32, 33, 45, 51) and the expression of p16 protein respectively in 93 cases of formalin-fixed, paraffin-imbedded specimens, which contained 46 cases of LPs [adult-onset laryngeal papilloma (ALP) 21, juvenile-onset laryngeal papilloma (JLP)25], 26 cases of LCs, 6 cases of normal tissues adjacent to carcinoma, and 15 cases of vocal noduli.

RESULTS

(1) The difference of positive rates of HPV-DNA in JLP group (84%, 21/25) and other groups were statistically significant (chi 2 test, P < 0.05). The difference of positive rates of HPV-DNA in ALPs(38.1%, 8/21), in LCs(19.2%, 5/26), in vocal noduli(0%, 0/15), and in normal tissues adjacent to carcinoma(0%, 0/6) were not significant statistically (chi 2 test or Fisher's exact probability test, P > 0.05). (2) The positive rates of expression of p16 protein in ALP group(57.1%, 12/21) and LC group(38.5%, 10/26) were significantly lower than that in vocal nodule group(93.3%, 14/15), in JLP group(88%, 22/25), and in normal tissues adjacent to carcinoma group (100%, 6/6) (chi 2 test or Fisher's exact probability test, P > 0.05). There were no significant differences of positive rates of expression of p16 protein between ALP group and LC group, and between JLP group and vocal nodule group (chi 2 test, P > 0.05). (3) In LPs, the difference of positive rates of p16 protein expression between HPV positive cases and HPV negative cases was significant statistically (chi 2 test, P < 0.05). In LCs, there was no difference in p16 protein expression rate between the two teams(Fisher exact probability test, P > 0.05).

CONCLUSION

The pathogenesis of JLP is closely associated with HPV infection and not associated with the inactivation of p16 gene. Conversely, the pathogenesis of ALP and LC is associated with the inactivation of p16 gene and not associated with the HPV infection.

Increased severity of HSV-1 keratitis and mortality in mice lacking the 2-5A-dependent RNase L gene

PURPOSE

The2',5'-oligoadenylate-dependent RNase L gene functions in the interferon-inducible RNA decay pathway known as the 2-5A system. The purpose of this study was to determine whether the absence of this gene affects the pathogenesis of herpes simplex virus type 1 (HSV-1) ocular infection in the mouse.

METHODS

HSV-1 (strain McKrae) was applied bilaterally to unscarified corneas of RNase L-null mice and congenic controls. To evaluate the severity of herpetic keratitis, slit lamp examinations (SLE) were performed every other day for 14 days. To study corneal histology and apoptosis, HSV-1-inoculated RNase-L-null and congenic control mice, as well as mock-inoculated mice (apoptosis negative control), were killed at 6 and 18 hours postinoculation (PI). Uninoculated mice that underwent corneal scarification (apoptosis positive control) were killed 2 hours after scarification. Eyes were dissected and the corneas processed for light and transmission electron microscopy and the TUNEL assay.

RESULTS

In comparison with the congenic control mice, RNase L-null mice showed significantly more severe herpetic keratitis (PI day 8, SLE score, mean +/- SEM: 3.27 +/- 0.10 vs. 2.34 +/- 0.06; P: < 0.001) and significantly higher mortality (PI day 14, 70% vs. 20%; P: < 0.001). Few apoptotic cells were seen in HSV-1-infected RNase L-null mice, although DNA fragmentation consistent with apoptosis was detected in the corneas of congenic control mice 6 and 18 hours after HSV-1 inoculation and in uninfected mice with scarified corneas. Signs of apoptosis were not present in the mock-infected corneas. Electron microscopic evidence of keratocytic apoptosis was detected only in the uninfected scarified corneas and the HSV-1-infected congenic control corneas.

CONCLUSIONS

The increased severity of ocular disease and increased mortality in the RNase L-null mice provides evidence, for the first time, that the 2-5A system contributes to protection during ocular herpetic infection. The reduced frequency of apoptosis in these mice suggests that one possible mechanism for this protective effect could be the induction of apoptosis in corneal cells as a means of reducing the spread of infectious virus.