[Experimental research on preparation of small root canals with EDTA and cirtric acid]

OBJECTIVE:To study the effects of EDTA and citric acid on small root canals so as to provide experimental basis for clinical applications.METHODS:17% EDTA and 50% citric acid are applied to Group A and Group B respectively for three days, each group having 14 extracted teeth with small root canals. The data obtained during the three days' experiment are analyzed with statistic method.RESULTS:The 14 small root canals applied with 17% EDTA solution for three days are all effective, the overall effectiveness rate being 100% and 11 small root canals show an expansion level of 4mm or over, 9 of which reachthe length required for treatment, 11 out of the 14 small root canals applied with 50% citric acid solution for three days are effective (three are not effective), the overall effectiveness rate being 78.57%. 8 small root canals show an expansion level of over 4 mm and all of them reach the length required for treatment.Based upon statistic treatment, the expansion level of small root canals of both Group A and Group B has an obvious difference (P<0.01) after the application.CONCLUSION:EDTA should be the recommended medicine for chemical preparation of small root canals.

The rapid inhibitory effect of glucocorticoid on cytosolic free Ca2+ increment induced by high extracellular K+ and its underlying mechanism in PC12 cells

The effect of glucocorticoid(GC) on peak cytosolic free calcium net increment (delta[Ca2+]i) induced by high-K+ was detected with MiraCal Image System. The main results were as follows: (1) Corticosterone(B) could inhibit delta[Ca2+]i in a time-dependent and concentration-dependent manner. (2) The inhibitory effect of B could be mimicked by bovine-serum albumin conjugated corticosterone (B-BSA) also in a dose-dependent manner. (3) G-protein inhibitor, either PTX or GDP beta S significantly reduced the inhibitory effect of B and B-BSA on delta[Ca2+]i (4) PMA, a stimulator for protein kinase C(PKC), could inhibit delta[Ca2+]i. (5) Although the inhibitors of PKC, chelerythrine chloride and bisindolylamide I per se had no influence on delta[Ca2+]i, but they significantly antagonized the inhibitory effect of B and B-BSA on delta[Ca2+]i. It is postulated that GC inhibit delta[Ca2+]i induced by high-K+ through a membrane mechanism and by a pathway involving G-protein and PKC.

The opening of a single base without perturbations of neighboring nucleotides: a study on crystal B-DNA duplex d(CGCGAATTCGCG)2

In this work we explore the possibility of the opening of a single base without perturbation of its neighboring nucleotides. Low energy base opening into the grooves can be accomplished by rotation of the relevant backbone and glycosidic bond torsion angles. The pathway has been determined by identifying zeta torsion angle as the reaction coordinate together with the accompanying geometric requirement that guides the displacement of other torsion angles. Our study on Dickerson dodecamer duplex d(CGCGAATTCGCG)2 showed that all bases with normal equilibrium zeta can be rotated by approximately 30 degrees, corresponding to approximately 3.5A base displacement, towards the major groove. Such an opening extent is comparable with estimated amplitudes of local angular motions in DNA bases from NMR experiments, which might facilitate proton exchange. The computed base opening energy barrier is also comparable with measured base pair opening enthalpy. These results indicate possible relevance of the pathway studied in this work with experimentally observed base pair opening process. Our analysis also showed a preference for base opening along the major groove and an abnormal opening behavior for bases with unusual equilibrium zeta torsion angle.

[Synthesis of epipodophyllotoxin carboxylates and antitumor activity in vitro]

A series of epipodophyllotoxin carboxylates were prepared from podophyllotoxin by reacting with organic acids under the catalysis of BF3.Et2O. All these products were characterized through IR, 1HNMR, MS and elemental analysis. These compounds showed significant antitumor activities against mouse leukemia P388 and human stomach cancer SGC-7901 in pharmacological tests in vitro.

[Ionic mechanism of hyperpolarization induced by glucocorticoid in mammalian neurons]

The rapid membrane actions of glucocorticoid were investigated by intracellular electrical recording from 383 coeliac ganglion neurons of guinea-pig in vitro. Thirty-eight neurons were hyperpolarizaed by 2-12 mV when perfused with 1 mumol/L hydrocortisone 21-hemisuccinate (F-suc), associated with a decrease in input membrane resistance. The hyperpolarization was dose-dependent. Nine neurons were depolarized, and the other 336 neurons were unresponsive. The membrane current was also observed with discontinuous single-electrode voltage clamp technique under perfusion of F-suc in another 43 neurons. In five neurons the current was found outward, but it was inward in one neuron. The hyperpolarization persisted after the elimination of synaptic input by low Ca2+ high Mg2+ perfusion and the suppression of protein synthesis by antinomycin D. The reversal potential of F-suc hyperpolarization is -79 +/- 4.3 mV (n = 5). F-suc induced hyperpolarization and GABA induced depolarization could occur in same neuron. The later action could be blocked by picrotoxin. F-suc induced hyperpolarization could be inhibited by TEA and 4-AP, but not picrotoxin. It is suggested that the F-suc's hyperpoalrization is mediated by potassium channel rather than Cl- channel in the sympathetic ganglion neurons.

[The synthetic fragment of rabbit blastocyst peptide2 and its physiological significance relevant to the mechanism of implantation]

The amino acid sequence of purified rabbit blastocyst peptide2 (RBP2) was analyzed. It contains 54 amino acids and it's sequence from aa4 to aa34 is the same as the N-terminal sequence of uteroglobin. An active antigenic region consisting of 15 aa residues (aa20-aa34) of the RBP2 was selected and designated as a synthetic peptide fragment (SPF). The effect of SPF on lymphocyte proliferation was analyzed by immunocytochemical assay detecting BrdU incorporation in the cellular DNA. The results indicated that no obvious inhibitory effect of SPF on T cell proliferation at concentrations ranging from 80 to 320 micrograms/ml was observed, while RBP2 at the concentrations ranging from 20 to 160 micrograms/ml had a significant effect in a dose dependent manner, suggesting that the immuno-suppressive effect of SPF is less than that of RBP2. We have also observed that SPF at concentrations ranging from 45 to 180 micrograms/ml inhibited PGF2 alpha secretion in a dose dependent manner. On the other hand, the 3H-leucine incorporation of rabbit endometrium was enhanced by SPF (180 micrograms/ml) and this action was blocked by addition of protein inhibitory agent, actidine.

[The high affinity uptake of glutamate in nervous system and its regulation by various factors]

The high affinity uptake of glutamate in nervous system is sodium dependent and is mediated by glutamate transporter proteins located both in the nerve endings which release glutamate as a transmitter and in the plasma membrane of glial cells. Four subtypes (GLUT1, GLAST, EAAC1 and EAAT4) of glutamate transporters have been cloned. The localizations, distributions and pharmacological properties for each of these subtypes are unique from one another. The high affinity uptake of glutamate is regulated by various factors, such as arachidonic acid, nitric oxide, free oxygen radicals, protein kinases, cytokines and growth factors. The regulations are obviously meaningful from the standpoint of physiology and/or pathophysiology.

[Studies on isolation, purification and structure of polysaccharide RHG from Hedysarum polybotrys Hand.-Mazz]

A water-soluble polysaccharide, RHG, was isolated from the roots of Hedysarum polybotrys Hand.-Mazz. It was shown to be homogeneous by electrophoresis and gel filtration. Its average molecular weight was estimated to be 1.4 x 10(4). Methylation analysis, periodate oxidation, Smith degradation, IR, NMR and KI-I2 reaction showed that RHG is a (1-4) linked alpha-D-glucan to which the glucosyl side chains are attached at O-6 of the glucosyl residues of the main chain.

[Studies on chemical constituents of Kadsura Longepedunculata]

The chemical constituents of Kadsura Longepedunculata collected from Zhejiang province were studied. Six compounds were isolated and their structures were elucidated based on physical and spectral analysis. Among them, one is a new compound, which is named kadsulactone acid (I) and the others are kadsulactone (II), (+)-anwulignan (III), mesodihydroguaiaretic acid (IV), d-epidalbacin(V) and beta-sitosterol (VI).

A single residue polymorphism at DR beta 37 affects recognition of peptides by T cells

Single amino acid polymorphism at residue 37 of the HLA-DR beta chain (DR beta 37) between DRB1*0406 and 0403 markedly influences susceptibility to the insulin autoimmune syndrome. We investigated the effects of DR beta 37 polymorphism regarding recognition of nonself peptides by a T-cell clone, YN5-32, specific to a streptococcal peptide (M12p54-68) presented by the DRB1*0406 molecule. YN5-32 responded better to M12p54-68 presented by allogeneic DRB1*0403 with a single Tyr-substitution at DR beta 37-Ser of the DRB1*0406 molecule. One hundred and fifty-four peptides carrying single residue substitutions at each of the core residues 57-65 of M12p54-68, were tested for full agonistic and TCR antagonistic activities. Forty-six peptides showed full agonism, 34 analogues exhibited TCR antagonism, and 45 analogues exhibited neither full agonism nor TCR antagonism, irrespective of the presenting molecules (DRB1*0406 or 0403). On the other hand, 29 analogue peptides substituted at each of residues 57-63 of M12p54-68 were recognized differently by YN5-32, depending on the presenting molecules. These observations indicate that 1) single amino acid polymorphism (Ser-Tyr) at the DR beta 37 residue induced a conformational change distinguished by TCR in some but not all peptides; and 2) these conformational changes were observed even in analogue peptides carrying single residue substitutions at residues far from a putative DR beta 37 contact site. These findings provide further evidence for altered human T-cell responses induced by TCR ligands with minor modifications.

Vibrational normal modes and dynamical stability of DNA triplex poly(dA). 2poly(dT): S-type structure is more stable and in better agreement with observations in solution

A normal-mode and statistical mechanical calculation was carried out to determine the vibrational normal modes, contribution of internal fluctuations to the free energy, and hydrogen bond disruption of DNA triplex poly(dA).2poly(dT). The calculation was performed on both the x-ray fiber diffraction model with a N-type sugar conformation, and a newly proposed model with a S-type sugar conformation. Our calculated normal modes for the S-type structure are in better agreement with observed IR spectra for samples in D2O solution. We also find that the contribution of internal fluctuations to free energy, premelting hydrogen bond disruption probability, and hydrogen bond melting temperatures for the Hoogsteen and Watson-Crick hydrogen bonds all show that the S-type structure is dynamically more stable than the N-type structure in a nominal solution environment. Therefore our calculation supports experimental findings that the triplex d(T)n.d(A)nd(T)n most likely adopts a S-type sugar conformation in solution or at high humidity. Our calculations, however, do not preclude the possibility of an N-type conformation at lower humidities.

Vibrational analysis of phosphorothioate DNA: II. The POS group in the model compound dimethyl phosphorothioate [(CH3O)2(POS)]-

The results of Raman and Infrared (IR) spectroscopic investigations on the vibrational modes of dimethyl phosphorothioate (DMPS) anion, [(CH3O)2(POS)]-, are reported. Ab initio calculations of the vibrational modes, the IR and Raman spectra and the interatomic force constants of DMPS were performed. A normal mode calculation was performed and the results were used to calculate the potential energy distribution for the vibrational modes. This analysis shows that in DMPS the P-S stretching mode has a frequency of about 630 cm-1 and an angle bending mode involving the sulfur atom has a frequency of about 440 cm-1. The proposed vibrational mode assignments will serve as marker bands in the conformational studies of phosphorothioate oligonucleotides which play a central role in the novel antisense therapeutic paradigm.

Thrombospondin, a negative modulator of megakaryocytopoiesis

The effects of native thrombospondin (TSP), an 18 kd recombinant protein comprising residues 1-174 of TSP (TSP1-174) with heparin-binding domain and a fusion protein comprising residues 559-669 of TSP (TSP559-669) on murine hematopoiesis, were studied by using different in vitro culture systems. TSP by itself did not show an inhibitory effect on colony-forming unit-megakaryocyte (CFU-MK) growth in a serum-free agar system and on the growth of colony-forming unit-granulocyte and macrophage (CFU-GM) in a plasma clot system. It was, however, found that in the plasma clot culture system when using aplastic anemia serum as the source of thrombopoietin or C-Mpl ligand (TPO), TSP and TSP1-174, but not TSP559-669, were able to inhibit the growth of CFU-MK from unfractionated and lineage negative (Lin-) bone marrow cells in a dose-dependent manner. A statistically significant suppression was seen at 1 microg/ml of TSP and 5 microg/ml of TSP1-174. This inhibitory effect of TSP was further found in both the serum-free agar system and the plasma clot system without aplastic anemia serum, where megakaryocyte colony growth was stimulated by recombinant TPO, basic fibroblast growth factor (bFGF), or interleukin-3 (IL-3). In a methylcellulose system, where a combination of stem cell factor (SCF), IL-3, and granulocyte/macrophage colony-stimulating factor (GM-CSF) were used, TSP inhibited the growth of colony-forming unit-granulocyte-erythroblast, megakaryocyte, and macrophage (CFU-GEMM) but not CFU-GM and burst-forming unit-erythroblast (BFU-E). Interestingly, this inhibitory effect of TSP on megakaryocyte colony growth could be counteracted by Fraxiparin, a low-molecular-weight heparin. These results demonstrate that TSP is a negative modulator of megakaryocytopoiesis and suggest that its inhibitory effect is at least partially mediated by N-terminal heparin-binding domain.

Triterpenoid saponins from Anemone hupehensis

Two new triterpenoid saponins, named hupehensis saponin F and G, were isolated from the water soluble part of Anemone hupehensis Lemoine. By chemical and spectroscopic evidence, their structures were elucidated as 3-O-beta-D-ribopyranosyl(1-->3)-alpha-L-rhamnopyranosyl(1--> 2)-alpha-L-arabinopyranosyl hederagennin-28-O-alpha-rhamnopyranosyl(1--> 4)-beta-D-glucopyranosyl(1-->6)-beta-D-glucopyranosyl(1--> 3)-alpha-L-rhamnopyranosyl(1-->4)-beta-glucopyranosyl(1--> 6)-beta-D-glucopyranoside and 3-O-beta-D-ribopyranosyl(1-->3)-alpha-L-rhamnopyranosyl(1--> 2)-alpha-L-arabinopyranosyl hederagenin-28-O-beta-glucopyranosyl(1-->3)-alpha-rhamnopyranosyl( 1--> 4)-beta-D-glucopyranosyl(1-->6)-beta-D-glucopyranosyl(1--> 3)-alpha-L-rhamnopyranosyl(1-->4)-beta-D-glucopyranosyl(1--> 6)-beta-D-glucopyranoside, respectively.

Synthesis and antitumor activity of spin labeled derivatives of podophyllotoxin

Three new nitroxyl labeled derivatives of podophyllotoxin 4-6 have been synthesized and evaluated for their antitumor activity in vitro. Compounds 4-6 showed significant inhibitory activity against human nasopharyngeal carcinoma KB,lung cancer A549 and stomach carcinoma SGC-7901 cells, as well as mouse leukemia L1210 and P388 cells. Compounds 4 and 5 exhibited comparable or superior activity to clinically used etoposide (VP-16,2) in their inhibition of these cell lines.

Temperature and impedance monitoring during radiofrequency catheter ablation of slow AV node pathway in patients with atrioventricular node reentrant tachycardia

This study was designed to observe the changes of temperature and impedance and to find the role of temperature control in radiofrequency ablation of slow pathways in patients with AV node reentrant tachycardia. Power, impedance and temperature were measured during each application of radiofrequency energy while the generator was operated in the power control mode. A total of 760 applications were delivered in 76 patients. The success rate was 100% without recurrence during a follow-up period of 8 +/- 3 months. The mean catheter tip temperature associated with successful ablation was 51.3 +/- 5.4 degrees C (range 45 degrees C to 64 degrees C), and significantly higher than the unsuccessful pulses (48.7 +/- 6.2 degrees C, P < 0.05). The mean temperature was 49.8 +/- 3.1 degrees C during accelerated junctional rhythm, significantly higher than the pulses without this rhythm. The mean temperature correlated well with early decrease of impedance (r = 0.71, P < 0.001), and an early decrease of impedance more than 5 ohms had an 87% positive predictive value for adequate tissue heating. These data suggested that, if temperature monitoring was available, setting the target temperature at about 51 degrees C could achieve adequate tissue heating for successful ablation of slow pathway; if not, impedance monitoring with an early decrease of impedance < 5 ohms could predict adequate tissue heating.

[Fast modulation of glutamate and GABA receptor--mediate electrophysiological responses by glucocorticoid]

Fast modulation by glucocorticoid on gluatmate and GABA receptor-mediated electrophysiological responses was investigated by extracellular iontophoresis and intracellular techniques in rat hypothalamic brain slices and guinea pig coeliac ganglion preparations respectively. The results were as follows: Glucocorticoid inhibited the glutamate receptor-mediated excitatory response and potentiated the GABA receptor-mediated inhibitory response within 5 min after perfusion. All these responses are reversible after removal of the glucocorticoid. Low Ca2+ high Mg2+ medium was ineffective to block the fast modulatory effects of glucocorticoid on the gluatmate and GABA receptor-mediated responses. It appears that the latter responses are mediated through some non-genomic mechanism without an involvement of synaptic circuitry.

Response of a human T cell clone to a large panel of altered peptide ligands carrying single residue substitutions in an antigenic peptide: characterization and frequencies of TCR agonism and TCR antagonism with or without partial activation

A CD4+ human T cell clone YN5-32 recognized a streptococcal M12p54-68 peptide in the context of HLA-DR4 and produced a large amount of IFN-gamma. We investigated responses of YN5-32 to 156 independent analogue peptides carrying single residue substitutions at residues 57 (position 1 (p1)) to 65 (p9) of the peptide. Approximately 30% of analogues at either Leu57 (p1), Ala60 (p4), or Asn62 (p6) residues exhibited TCR agonism to stimulate various magnitudes of proliferative responses in the T cell clone, and analogues exhibiting TCR antagonism are rare in these three residues. In analogues at either Glu58 (p2), Gln59 (p3), Tyr61 (p5), or Glu63 (p7) residue, 30 to 50% exhibited TCR antagonism. About 10% of analogues at Glu58 (p2) or Tyr61 (p5) stimulated proliferative responses, while 30 to 50% of analogues at Gln59 (p3) or Glu63 (p7) did so. Some of these TCR antagonistic analogues carrying relatively conservative amino acid substitutions partially activated the T cells to induce large increases in size and expression levels of CD4, CD11a (LFA-1), CD28, CD49d (VLA-4), and CD95 (Fas), and small increases in CD25 and CD44 expressions on the cell surface. None of the partially activating antagonistic analogues induced IFN-gamma production or anergy in T cells. Analogues with replacements of acidic amino acids at either Leu64 (p8) or Ser65 (p9) residue had dominant negative effects on T cell proliferation. Thus, altered peptide ligands with single residue substitutions in the antigenic peptide frequently stimulated the human T cell clone, in at least three different ways to exhibit agonism, antagonism, and antagonism with partial activation. Frequencies of analogue peptides exhibiting these three different effects on the T cell clone differed depending on the residue of the peptide substituted. Altered T cell responses induced by analogue peptides of a T cell epitope provide a system to analyze activation signals mediated by TCR, and to manipulate T cell responses.

Response of a human T cell clone to a large panel of altered peptide ligands carrying single residue substitutions in an antigenic peptide: characterization and frequencies of TCR agonism and TCR antagonism with or without partial activation

A CD4+ human T cell clone YN5-32 recognized a streptococcal M12p54-68 peptide in the context of HLA-DR4 and produced a large amount of IFN-gamma. We investigated responses of YN5-32 to 156 independent analogue peptides carrying single residue substitutions at residues 57 (position 1 (p1)) to 65 (p9) of the peptide. Approximately 30% of analogues at either Leu57 (p1), Ala60 (p4), or Asn62 (p6) residues exhibited TCR agonism to stimulate various magnitudes of proliferative responses in the T cell clone, and analogues exhibiting TCR antagonism are rare in these three residues. In analogues at either Glu58 (p2), Gln59 (p3), Tyr61 (p5), or Glu63 (p7) residue, 30 to 50% exhibited TCR antagonism. About 10% of analogues at Glu58 (p2) or Tyr61 (p5) stimulated proliferative responses, while 30 to 50% of analogues at Gln59 (p3) or Glu63 (p7) did so. Some of these TCR antagonistic analogues carrying relatively conservative amino acid substitutions partially activated the T cells to induce large increases in size and expression levels of CD4, CD11a (LFA-1), CD28, CD49d (VLA-4), and CD95 (Fas), and small increases in CD25 and CD44 expressions on the cell surface. None of the partially activating antagonistic analogues induced IFN-gamma production or anergy in T cells. Analogues with replacements of acidic amino acids at either Leu64 (p8) or Ser65 (p9) residue had dominant negative effects on T cell proliferation. Thus, altered peptide ligands with single residue substitutions in the antigenic peptide frequently stimulated the human T cell clone, in at least three different ways to exhibit agonism, antagonism, and antagonism with partial activation. Frequencies of analogue peptides exhibiting these three different effects on the T cell clone differed depending on the residue of the peptide substituted. Altered T cell responses induced by analogue peptides of a T cell epitope provide a system to analyze activation signals mediated by TCR, and to manipulate T cell responses.

Sequence and temperature effect on hydrogen bond disruption in DNA determined by a statistical analysis

We use the modified self-consistent phonon approximation theory to calculate temperature dependent interbase hydrogen bond disruption profiles for a number of six base pair repeating sequence infinite B-DNA polymers with various guanine-cytosine/adenine-thymine ratios. For comparison we also include results we have obtained in our earlier work on several B-DNA homopolymers, copolymers and a four-base-pair repeating sequence polymer. Our theory gives a statistical estimate of thermal fluctuational disruption probability of individual hydrogen bonds in individual base pairs in DNA as a function of temperature. The calculated probabilities show no sequence dependence at premelting temperatures, in agreement with proton exchange measurements. These probabilities however become very sensitive to base sequence at temperatures close to the observed melting temperatures. Multiphasic critical transitions are found in which a portion of base pairs are disrupted at temperature below the final disruption temperature. These transitions include localized as well as non-localized base pair opening. The localized transitions involve disruption of a few base-pairs at every other location without large scale base unstacking, and they may not appear in the observed UV curves with current resolution. On the other hand the overall disruption behavior is consistent with observations. The midpoint transition temperatures are close to the observed melting temperatures and these temperatures show the observed linear dependence on guanine-cytosine content. Our calculations indicate that our theory can be used effectively to calculate H-bond disruption behavior of different DNA sequences.

[Bovine serum albumin-conjugated corticosterone inhibits the release of arginine vasopressin]

The arginine vasopressin (AVP) released from rat hypothalamic slices containing paraventricular and supraoptic nuclei sectioned with vibratome and incubated in microchambers was measured by radioimmunoassay. The effect of bovine serum albumin-conjugated corticosterone (B-BSA) on the AVP release was investigated. The results were as follows: (1) B-BSA, within 20 min, inhibited the AVP release in a dose-dependent manner from 10(-7) to 10(-4) mol/L. (2) The inhibitory effect of B-BSA was partially blocked by RU486 (10(-4)-10(-3) mol/L). (3) With the elevation of Ca2+ in the incubation medium the inhibitory effect of B-BSA was enhanced. (4) The inhibitory effect of B-BSA was also enhanced in the presence of neomycin (10(-3)-10(-2) mol/L). These results suggested that glucocorticoid, without entering into cells, could inhibit AVP release from rat hypothalamic slices. This effect might be mediated via a non-genomic mechanism involving a change of Ca2+ influx across the cell membrane.

Melting profile and temperature dependent binding constant of an anticancer drug daunomycin-DNA complex

We calculate thermal fluctuational base pair opening probability and the drug binding constant of a daunomycin-bound Poly d(CGTA).Poly d(TACG) at temperatures from room temperature to its melting temperature. For comparison we also carry out a calculation on a drug-free DNA with the same sequence. Our calculations are carried out by means of a statistical approach using microscopic structures and established force fields and with cooperative effects incorporated into the algorithm. Both hydrogen bond disruption probabilities and drug unstacking probability are determined self-consistently. These probabilities are then used to determine temperature dependent base pair opening probabilities and the drug binding constant. The calculated base pair opening probabilities and drug binding constant are found to be in fair agreement with experiments carried out at room temperature. Our calculation shows cooperative base pair disruption and drug dissociation at certain critical temperatures close to the observed melting temperatures for similar helices. We find that the temperature dependence of the drug binding constant fits well to the van't Hoff relation, in agreement with observations. Our calculation indicates the occurrence of a premelting transition in the drug-bound DNA helix. Some comments are made about this premelting transition.

Some lifestyle factors in human lung cancer: a case-control study of 792 lung cancer cases

In order to investigate the relationship between some lifestyle factors and lung cancer, a case-control study involving all lung cancer deaths registered in 1986 was performed. The results show that among males, 92.5% of the cases and 75.5% of controls were smokers, implying that cigarette smoking is a primary risk factor for lung cancer in males. By contrast, among females only 60.6% of the cases and 30.8% of the controls were smokers, implying factors other than cigarette smoking must be involved in the development of lung cancer in females. The risk of lung cancer in nonsmoking females was found to be unaffected by exposure to environmental tobacco smoke (ETS). A study of diet and eating habits showed that in males the risk of lung cancer was reduced by the intake of vegetables and fruits, but was significantly increased by a frequent intake of fried foods. The positive association between the intake of fried food and the risk of lung cancer could result from cooking practices and from inappropriate methods used in food preparation. No association can be demonstrated between the consumption of high protein or high fat diets, salty and smoked food items and the incidence of lung cancer. Thus, it is not likely that sufficient lung cancer inducing carcinogens can be generated through the intake of food. In addition, the positive association found to exist between the living index and the risk of lung cancer in females is consistent with the notion that coal smoke or cooking practices may generate sufficient indoor air pollutants to significantly increase the risk of lung cancer in females.

An epidemiological study of risk factors for lung cancer in Guangzhou, China

Lung cancer has been on a rapid rise worldwide during the last three or four decades, in part due to modern social habits and unhealthy lifestyles. Although smoking, air pollution, and certain types of occupational exposure have been recognized as the major risk factors for lung cancer, the significance of each of these factors appears to vary with sex, country, and with region within a given country. In the case of nonsmoking females, some risk factors for lung cancer remain to be identified. In the city of Guangzhou, lung cancer is one of the five leading tumors and the rate has been increasing steadily in both males and females since the 1970s. In this report, more than 6000 cases of lung cancer deaths, accumulated over the past 9 years, were analyzed. The severity of air pollution and cigarette smoking were positively correlated with the incidence of lung cancer deaths. Analysis of levels of SO2 and NOx suggests that the major source of indoor air pollution came from cooking. Two studies were performed in order to determine the relative contribution and importance of smoking, indoor air pollution and occupational exposure as risk factors for the rising incidence of lung cancer. The first was a population-based case-control study involving 849 subjects (566 males and 283 females). The second study was based on the data made available by the Third National Census survey, in which the standardized mortality rate (SMR) and population attributable risk (PAR) for lung cancer due to occupational exposure for the population in Guangzhou were analyzed. Results of these two studies show that: in females, indoor air pollution, derived primarily from burning coal, was found to be a highly significant risk factor for lung cancer. In males, however, cigarette smoking and occupational exposure were significantly associated with lung cancer. To further elucidate the contribution of indoor air pollution as a risk factor for lung cancer in nonsmoking females, two additional case-control studies were performed in 1985 and 1986. The 1985 study involved 120 nonsmokers (28 males, 92 females) in which the influence of such lifestyle factors as: personal history of nonmalignant respiratory diseases, fresh vegetable consumption, lifetime occupation and occupational exposure histories, exposure to environmental tobacco smoke (ETS), degree of indoor air pollution, general conditions of home residence, cooking practices and environments, and family history of cancer were first individually assessed and then collectively subjected to multiple conditional regression analysis for evaluation as risk factors for lung cancer. The 1986 study involved 75 cases of never-smoking females in which the aim was to investigate the influence of exposure to spousal smoke as a risk factor for lung cancer. These studies suggest that consumption of fresh vegetables was a "protective" factor for lung cancer in both males and females. In females, indoor air pollution and size of the kitchen were risk factors for lung cancer, whereas ETS exposure, respiratory disease history, family history of cancer, living conditions, use of cooking fuel, and participation in cooking, were not statistically associated with female lung cancer deaths. Occupational exposure was also correlated with the incidence of female lung cancer deaths. In males, chemists had the highest SMR, whereas in females, homemakers had the highest SMR. In males, the most common lung cancer cell type was squamous cell carcinoma, whereas in females adenocarcinoma was the most predominant type. The factors affecting the distribution of histologic lung cancer cell types were also investigated and discussed.

The protective effects of long-acting recombinant human pancreatic secretory trypsin inhibitor (R44S-PSTI) in a rat model of cerulein-induced pancreatitis

The effects of pancreatic secretory trypsin inhibitor (PSTI) on cerulein-induced pancreatitis were studied in a rat model. Arg44 of PSTI was replaced by Ser using site-directed mutagenesis (R44S-PSTI). R44S-PSTI has a longer half-life than the natural form. Pancreatitis was induced by four intramuscular injections of cerulein (50 microgram/kg at 1 h intervals). Continuous intravenous infusion of R44S-PSTI began at a dose of 20 micrograms/kg/h 30 min before the first cerulein injection, and was completed 3 h after the last cerulein injection. Tumour necrosis factor (TNF-alpha) production by isolated peritoneal macrophages from rats with cerulein-induced pancreatitis increased following lipopolysaccharide stimulation, compared to control rats (P < 0.01). R44S-PSTI administration significantly decreased the TNF-alpha production by peritoneal macrophages from rats with cerulein-induced pancreatitis (P < 0.05). In addition, R44S-PSTI significantly reduced serum amylase activity (P < 0.01) and pancreatic wet weight after pancreatitis induction (P < 0.05). Histological examination revealed marked acinar cell vacuolization, interstitial oedema, and cellular infiltration in cerulein-induced pancreatitis, but a lesser degree of histological change in rats that were treated with R44S-PSTI. Prophylactic use of intravenous R44S-PSTI infusion may reduce the severity of acute pancreatitis either histologically or serologically.

Single amino acid substitutions on a Japanese cedar pollen allergen (Cry j 1)-derived peptide induced alterations in human T cell responses and T cell receptor antagonism

We generated T cell clones specific to a Japanese cedar pollen allergen (Cry j 1) and investigated effects of altered T cell receptor (TCR) ligand on changes of T cell responses. One of these Cry j 1-specific T cell clones established from patients with Japanese cedar pollinosis, ST1.9, recognized an antigenic peptide Cry j 1 p335-346 in the context of HLA-DRA+DRB3*0301 molecules and secreted interleukin-4 dominantly, with a smaller amount of interferon-gamma. ST1.9 represented one of the major T cell clones specific to Cry j 1 in the donor, because a short-term cultured polyclonal T cell line specific to Cry j 1 exhibited the same character as the ST1.9. We synthesized various analog peptides derived from Cry j 1 p335-346 with single amino acid substitutions and determined key residues for interactions between TCR of ST1.9 and HLA-DR molecules. We also analyzed changes in the responses of ST1.9 to Cry j 1 p335-346-derived analog peptides. Of interest was that the substitution of 339threonine to valine resulted in a significant increase in interferon-gamma production, with no remarkable changes either in proliferative response or interleukin-4 production. Analog peptides carrying the substitutions of 339threonine to glycine or glutamine revealed TCR antagonism, without changes in their binding affinities to the DR molecule. Therefore single amino acid substitutions on an allergen peptide carrying the T cell epitope may suppress helper-T-dependent class switch pressure to IgE in B cells either by inducing increased interferon-gamma production or by inhibiting proliferative responses in helper-T cells.

Membrane-mediated inhibition of corticosterone on the release of arginine vasopressin from rat hypothalamic slices

The arginine vasopressin (AVP) released from the hypothalamic slices containing paraventricular and supraoptic nuclei of Sprague-Dawley rats sectioned with vibratome and incubated in static microchambers was measured by radioimmunoassay. The effect of bovine serum albumin-conjugated corticosterone (B-BSA) on the AVP release was investigated. The results were as follows: (1) B-BSA, within 20 min, significantly inhibited AVP release in a dose-dependent manner from 10(-7) to 10(-4) mol/l. (2) RU38486 (10(-4)-10(-3) mol/l) could partially block the inhibitory effect of B-BSA although it by itself did not change the AVP release. (3) With the elevation of Ca2+ concentration in the incubation medium, the AVP release was increased and the inhibitory effect of B-BSA enhanced; while in the absence of Ca2+, the AVP release decreased and the effect of B-BSA attenuated. (4) The inhibitory effect of B-BSA was enhanced in the presence of neomycin which itself had no influence on AVP release. These results indicated that the inhibitory effect of corticosterone is rapid and membrane-mediated which is non-genomic rather than classical genomic, and that the extracellular Ca2+ play a role in this rapid inhibitory effect.

Nongenomic effect of glucocorticoid on the release of arginine vasopressin from hypothalamic slices in rats

The arginine vasopressin (AVP) released from the hypothalamic slices containing paraventricular and supraoptic nuclei of Sprague-Dawley rats sectioned with vibratome and incubated in static microchambers was measured by radioimmunoassay, and the rapid effect and its underlying mechanism of glucocorticoids (GC) on AVP release were investigated. The results were as follows: (1) AVP was steadily released at a rate of 9.1 +/- 1.2 pg/min/well for as long as 6 h. (2) Corticosterone (B), within 20 min, inhibited AVP release in a dose-dependent manner from 10(-7) to 10(-4) mol/l. (3) Cortisol, 17beta-estradiol, or testosterone (all in 10(-6) mol/l) to some extent also inhibited AVP release, but dexamethasone, aldosterone, progesterone, RU 38486 or cholesterol had no significant inhibition on AVP release. (4) The rapid inhibitory effect of B was not affected by actinomycin D, puromycin or colchicine. (5) RU 38486 (10(-5)-10(-3) mol/l) could partially block the rapid inhibitory effect of B, although it did not by itself change AVP release. (6) With the elevation of Ca2+ in the incubation medium, the AVP release was increased and the rapid inhibitory effect of B enhanced; while in the absence of Ca2+ the AVP release decreased and the effect of B attenuated. (7) The rapid inhibitory effect of B was enhanced in the presence of neomycin, although the latter had no influence on AVP release. (8) Aminophylline did not affect the rapid inhibitory effect of B. These results indicated that the rapid inhibitory effect of GC might be a nongenomic rather than the classical genomic one, and that the extracellular Ca2+ play a role in the rapid effect of GC on AVP release. The significance of the rapid action of GC in the rapid negative feedback regulation of AVP release from hypothalamus of rats was discussed.

Constitutive and selective expression of basic fibroblast growth factor in human leukaemia cell lines

We have previously shown that basic fibroblast growth factor (bFGF) stimulates megakaryocytopoiesis and granulopoiesis in vitro and that normal haematopoietic cells and several leukaemic cell lines express FGF receptors. In this paper, we demonstrate by reverse transcriptase-mediated polymerase chain reaction (RT-PCR) that bFGF mRNA is expressed in two leukaemia cell lines with megakaryocytic features (Meg-01 and K562), in two lymphocytic cell lines (Hut 78 and CA) and in normal human peripheral blood mononuclear cells. In addition, the conditioned media of Meg-01, but not Dami, contained a potent fibroblast-stimulating activity which could be neutralized by bFGF antibodies. Furthermore, bFGF antibody significantly inhibited the autocrine growth of Meg-01 cells in vitro. However, we could not detect cell-associated 18 kDa bFGF or HMW bFGF by immunofluorescence, immunoprecipitation or Western blotting. These data indicate that bFGF is expressed by certain haematopoietic cells and support further a role of this FGF prototype in haematopoiesis.

Binding characteristics of glucocorticoid receptor in synaptic plasma membrane from rat brain

The study was carried out to identify the specific glucocorticoid membrane binding site (GCMB) on synaptic plasma membrane (SPM), and to investigate the ligand binding properties and physico-chemical characteristics of GCMB. The radioligand binding assay showed that tritiated corticosterone ([3H]B) could bind to GCMB specifically with positive cooperativity. For SPM, the binding capacity (R(zero)) was 46.67 +/- 4.62 fmol/mg protein; the dissociation constant (Kd), 97.48 +/- 18.85 nmol/L, and the Hill coefficient, 1.633 +/- 0.082. Various steroids bound with GCMB in the following rank order: RU26752, aldosterone > corticosterone, cortisol > RU26988, progesterone, R5020, triamcinolone acetonide > testosterone, estradiol > RU38486 > dexamethasone. GCMB, which could be solubilized by detergent Triton X-100, showed thermal stability, although it was susceptible to hydrolysis by trypsin and to the reducing agent, mercaptoethanol. The addition of divalent cations (Ca2+, Mg2+) was beneficial to the ligand binding. The results strongly indicate that GCMB, fulfilling the basic criteria for a receptor, constitutes a novel type of glucocorticoid receptor on neuronal membrane which is significantly different from the cytosolic glucocorticoid receptors.

Normal mode calculation of a netropsin-DNA complex: effect of structural deformation on vibrational spectrum

Calculations of the normal mode spectrum of a netropsin-DNA complex, an isolated DNA helix of the same sequence, and a free netropsin molecule were carried out and compared with observations. We find that the frequency of modes of the complex that are primarily vibrations localized to the helix are relatively unchanged from the frequencies found for similar modes of the isolated helix. On the other hand, the frequencies of thosemodes of the complex that are found to be primarily in the netropsin are found to change significantly in the complex from that of the free netropsin. Further analysis indicates that the changes in the "netropsin modes" are primarily due to the conformational deformation induced in the netropsin by formation of the complex. All the frequencies and shifts in frequency are in good agreement with recent Raman measurements.

Sequence and temperature dependence of the interbase hydrogen-bond breathing modes in B-DNA polymers: comparison with low-frequency Raman peaks and their role in helix melting

We carry out temperature-dependent lattice dynamics calculations to determine the vibrational normal modes associated with the interbase H-bond breathing motion in several B-DNA copolymers at temperatures from room temperature to the melting temperatures. We take into consideration Raman selection rules and incorporate a simple empirical model of Raman susceptibility in the interbase H bonds in our calculation and compare them to Raman measurements. Our calculations are carried out using empirical force constants that are not further refined to low-frequency spectra. Our calculations show the existence of strong interbase H-bond breathing modes at frequencies and with relative oscillator strengths close to the observed Raman peaks in the range of 60-140 cm-1 for the DNA sequences considered except for one helix. The correlation between the calculated and observed frequencies and oscillator strengths indicates that the observed Raman peaks in the frequency range are likely interbase H-bond breathing modes. We find that these modes exhibit sizable temperature as well as sequence dependence. We show the softening of these modes on approaching thermal denaturation that is also in agreement with the observed behavior in Raman and melting measurements. The sensitivity of the calculation on the empirical model of Raman susceptibility and the possible reasons for the discrepancy between a few calculated values and observations are discussed.

[Effect of glucocorticoids and other steroids on arginine vasopressin release from rat hypothalamic slices]

Rat hypothalamic slices sectioned with vibratome (containing paraventricular and supraoptic nuclei) were incubated in static microchamber and the Arginine vasopressin (AVP) released from the slices was measured by radioimmunoassay. The effect of glucocorticoids (GC) and other steroids on AVP release was investigated. The results were as follows: (1) AVP was steadily released at a rate of 9.06 +/- 1.23 pg/min for as long as 6 h (not including the 90 min for recovery of slices). (2) Corticosterone (B) inhibited AVP release within 20 min in a dose-dependent manner from 10(-7) to 10(-4) mol/L. (3) Cortisol, 17 beta-estradiol, or testosterone (10(-6) mol/L) also inhibited AVP release within 20 min, but dexamethasone, aldosterone, progesterone, RU486, or cholesterol had no significant effect. (4) RU486 (10(-5)-10(-3) mol/L) could partially block the rapid inhibitory effect of corticosterone. These results suggested that GC might exert in situ a regulatory negative feedback action on the AVP release from hypothalamus of rat through a non-genomic rather than a genomic mechanism.

Interleukin-3 is an autocrine growth factor of human megakaryoblasts, the DAMI and MEG-01 cells

Interleukin-3 (IL-3), a cytokine known to be produced by activated T lymphocytes, mast cells, eosinophils and neutrophils, is a potent stimulator of normal haemopoiesis, particularly megakaryocytopoiesis. However, it remains unknown whether leukaemic megakaryoblasts can produce IL-3 and whether IL-3 is involved in the pathological process of megakaryoblastic leukaemia. In this study, several human leukaemia cell lines with or without megakaryocytic features, the DAMI, MEG-01, HEL, K562, HL-60 and U937, were chosen as the models. It was first demonstrated by reverse transcriptase-polymerase chain reaction (RT-PCR) and indirect immunofluorescence assay that IL-3 was expressed in DAMI and MEG-01 cells, but not in other cell lines, although two erythroleukaemic cells, the HEL and K562, also possess some megakaryocytic features. Interestingly, the mRNA for IL-3 receptor was detected in nearly all the cell lines except K562 cells, suggesting that expression of IL-3 and its receptor may be dissociated in most of the cell lines and that co-expression of IL-3 and its receptor exists in megakaryoblastic cell lines, the DAMI and MEG-01. Of the cell lines which did not express IL-3 under unstimulated condition, only HEL cells were able to express IL-3 mRNA after treatment with PMA for 72 h. Furthermore, the proliferation of DAMI and MEG-01 cells could be enhanced in the presence of IL-3 and suppressed by the anti-IL-3 antibody and the IL-3 antisense oligodexyonucleotides (ODNs). These findings indicate that IL-3, as an autocrine growth factor, is involved in the growth of some megakaryocytic leukaemia cell lines.

[Clinical analysis of 7 cases of parovarian borderline tumors]

Seven cases of primary parovarian borderline tumors are presented, Comprising 1.6% of 451 cases of parovarian cysts treated. The age range of the 7 cases was from 16 to 60, with a mean value of 37 years. Abdominal mass, lower abdominal pain or discomfort were chief clinical complaints. In one case, because of amenorrhea of 2 months' duration, the preoperative diagnosis was mistaken to be extra-uterine pregnancy. Surgical examination revealed normal appearance of ovaries and fallopian tubes. Smooth-surfaced cystic masses arising from the broad ligaments were found in all of the 7 cases, their size ranged from 3cm x 2cm x 1.5cm to 8cm x 8cm x 7cm. Internal papillary projections single or multiple, and clear serous fluid were seen in all of the 7 cystic specimens. Microscopically the cyst wall and papillary projections were lined with stratified cuboid or columnae epithelium. Abundant and complicated ramifications of the projections were seen. The nuclei showed slight to moderate metaplasia; mitoses were rare. 6 of the cases originated from paramesonephros and 1 ease was of mesonephric origin. The seven patients were living and well during a postoperative follow-up period of 12 months to 11 years. Literature review on primary parovarian borderline tumors, their clinical presentation, pathological characteristics, therapy and prognosis are presented and discussed.

[Pars plana lensectomy and anterior vitrectomy for the treatment of congenital subluxated lenses]

The conventional surgical management of congenital subluxated lenses is frequently associated with a high incidence of complications leading to poor visual prognosis. Lensectomy through the pars plana with modern techniques of microsurgery and automated suction-cutting devices was performed on 11 patients (18 eyes) whose pre-operative visual acuities with the best optical correction ranged from 0.05-0.3, which were improved postoperatively to 0.5-1.0 during a follow-up of 3 to 60 months with an average of 36 months. The complications were accidental small cuts at the pupillary borders of 3 eyes, indicating that pars plana lensectomy is a safe procedure for the treatment of congenital subluxated lenses.

[The pharmacology of the GABA-induced biphasic response in guinea-pig celiac ganglion neurons in vitro]

In guinea-pig celiac ganglion neurons, GABA induced a biphasic response, i.e. a depolarizing response associated with a resistance decrease followed by a hyperpolarizing response associated with a resistance increase. Such response persisted in low Ca2+ high Mg2+ medium. The GABA-induced biphasic response was mimicked by muscimol and inhibited by bicuculline methiodide (100 mumol/L) and picrotoxin (100-300 mumol/L). At doses producing almost equal depolarizing responses, muscimol was weaker in producing hyperpolarizing responses than GABA. Baclofen had no effect on membrane potentials of the ganglion cells. These results suggest that the depolarizing phase of the GABA-induced biphasic response is mediated by GABAA/Cl- ionophore receptor complex and the hyperpolarizing phase may be mediated by a novel type of GABA receptor possessing similar pharmacological properties as the classical GABAA receptor.

Premelting base pair opening probability and drug binding constant of a daunomycin-poly d(GCAT).poly d(ATGC) complex

We calculate room temperature thermal fluctuational base pair opening probability of a daunomycin-poly d(GCAT).poly d(ATGC) complex. This system is constructed at an atomic level of detail based on x-ray analysis of a crystal structure. The base pair opening probabilities are calculated from a modified self-consistent phonon approach of anharmonic lattice dynamics theory. We find that daunomycin binding substantially enhances the thermal stability of one of the base pairs adjacent the drug because of strong hydrogen bonding between the drug and the base. The possible effect of this enhanced stability on the drug inhibition of DNA transcription and replication is discussed. We also calculate the probability of drug dissociation from the helix based on the selfconsistent calculation of the probability of the disruption of drug-base H-bonds and the unstacking probability of the drug. The calculations can be used to determine the equilibrium drug binding constant which is found to be in good agreement with observations on similar daunomycin-DNA systems.

First- or second-order transition in the melting of repeat sequence DNA

Both theoretical analysis and observation of the continuity of the melted fraction of base pairs indicate that the melting transition in DNA is second order. Analysis of the salt dependence of the transition by polyelectrolyte limiting laws, however, has first-order dynamics imbedded in the analysis. This paper proposes that the observation taken to be a latent heat of melting in the limiting law analysis could instead be a specific heat anomaly associated with a second-order transition. The limiting laws can be reconstructed based on a second-order transition with a specific heat anomaly. The T2M dependence of this excess heat is also consistent with its being a specific heat anomaly of a system displaying classical critical behavior. Classical critical behavior indicates that theoretical mean field approaches such as MSPA should be particularly appropriate to helix melting studies.

Triterpenoid saponins from Anemone hupehensis

Four triterpenoid saponins were isolated from Anemone hupehensis. On the basis of chemical and spectroscopic evidence, two new saponins, hupehensis saponins D and E, were elucidated as 3-O-beta-D-glucopyranosyl (1-->3)-beta-D-ribopyranosyl (1-->3)-alpha-L-rhamnopyranosyl (1-->2)-alpha-L-arabinopyranosyl oleanolic acid-28-O-alpha-L-rhamnopyranosyl (1-->4)-beta-D-glucopyranosyl (1-->6)-beta-D-glucopyranoside and 3-O-beta-D-glucopyransoyl (1-->3-beta-D-ribopyranosyl (1-->3)-alpha-L-rhamnopyranosyl (1-->2)-alpha-L-arabinopyranosyl hederagenin-28-O-alpha-L-rhamnopyranosyl (1-->4)-beta-D-glucopyranosyl (1-->6)-beta-D-glucopyranoside. The two known saponins were identified as huzhangosides B and D.

[An analysis of the central pathway of vestibulo-sympathetic responses]

In order to elucidate the relationship between several structures of CNS and the vestibulo-sympathetic response (VSR) in rat, the technique of spike triggering average (STA) was used. The spike of the neuron which responded to the pendular rotation (pendular positive unit, PPU) was used to trigger the onset of averaged activities of the splanchnic nerve (SN). Making use of the spike of PPU of nucleus vestibularis medialis (NVM) as an indicator, the SN-STA had a latency of 33.28 +/- 3.1 ms. SN-STA triggered by PPU of reticular formation (RF) of caudal brain stem, a positive response with a latency of 11.13 +/- 0.91 ms was observed. SN-STA triggered by PPU of vestibulocerebellum, a positive response with a latency of 21.86 +/- 1.73 ms was observed. Our results suggest that the nearest supraspinal relay may be the nuclei of medical RF in caudal brain stem and the descending flow of VSR was probably transmitted by the slow conducted fibers of reticulo-spinal tract. According to the latency of SN-STA by PPU of vestibulo-cerebellum, the vestibulcerebellum possibly executed a polysynaptic mission between the transmission of VSR outflow from NVM to RF nuclei of caudal brain stem.

An old traditional herbal remedy for neonatal jaundice with a newly identified risk

Yin-chen (Artemisia scoparia) is a very popular intravenous herbal preparation used for the treatment of neonatal jaundice in China. Bilirubin-protein titration studies with the horse radish peroxidase method have shown that the herb is highly effective in displacing bilirubin from its protein binding. Free bilirubin is liberated in this process and this could increase the risk of brain damage in jaundiced infants. With the present state of knowledge, the use of traditional herbal therapies should be strongly discouraged in neonates.