A novel transduction mechanism mediating dopamine-induced vascular relaxation: opening of BKCa channels by cyclic AMP-induced stimulation of the cyclic GMP-dependent protein kinase

Dopamine dilates the coronary, renal and other vascular beds; however, the signaling pathway underlying this effect is unclear. In this study the signal-transduction process mediating dopamine-induced relaxation of porcine coronary arteries was investigated in isolated vessels and single arterial myocytes. Dopamine-induced relaxation of arteries was mediated through the DA- receptor and involved K+ efflux, and subsequent patch-clamp studies demonstrated that either dopamine or fenoldopam, a selective DA-1 agonist, increased the opening probability of the large-conductance, calcium- and voltage-activated K+ (BKCa) channel in coronary myocytes. Moreover, blockade of this channel by iberiotoxin prevented dopamine-induced coronary relaxation. Dopamine stimulation of BKCa channels was completely prevented by a DA-1-receptor antagonist, but was unaffected by propranolol. Furthermore, inhibiting adenylyl cyclase activity prevented stimulation of BKCa channel activity, whereas chlorophenylthio (CPT)-cyclic adenosine monophosphate (AMP), a membrane-permeable analog of cyclic AMP, mimicked the effects of dopamine. Interestingly, inhibiting the cyclic AMP-dependent protein kinase (PKA) did not affect the response to dopamine, whereas dopamine-induced channel activity was completely blocked by inhibiting the activity of the cyclic guanosine monophosphate (GMP)-dependent protein kinase (PKG). These findings demonstrate that activation of DA-1 receptors causes stimulation of BKCa channel activity by a mechanism involving cyclic AMP-dependent stimulation of PKG, but not PKA, and further suggest that this cross-reactivity mediates dopamine-induced coronary vasodilation.

Conceptually new sulfone analogues of the hormone 1alpha, 25-dihydroxyvitamin D(3): synthesis and preliminary biological evaluation

A conceptually new series of vitamin D(3)-like nonfluorinated and fluorinated 16-ene side chain tert-butyl sulfones 3-7 has been synthesized. Even though these novel C,D-ring side chain analogues of the hormone 1alpha,25-dihydroxyvitamin D(3) (1,1,25D(3)) lack a terminal OH group, thought previously to be essential for high biological activity, they are highly antiproliferative and, in several cases, transcriptionally active in vitro but desirably noncalcemic in vivo. The side chain sulfone group may be binding to the nVDR as a hydrogen-bond acceptor, in contrast to the hydrogen-bond donor function of the 25-OH group of natural 1,25D(3).

[Case-control studies on risk factors for pulmonary tuberculosis in servicemen of China]

OBJECTIVE

To study the risk factors for pulmonary tuberculosis (PTB) in the servicemen of armed forces and lay a basis for its prevention and control.

METHODS

A 1:2 matched case-control study was carried cut in the servicemen, with 86 cases and 153 controls. Data were analyzed with conditional logistic regression with EGRET software. Odds ratios (ORs) were calculated for the relevant factors.

RESULTS

Single-variable analysis showed that schooling, history of exposure to PTB, history of Bacille Calmette-Guérin (BCG) vaccination and BCG vaccination scar all associated with the incidence of PTB, with ORs of 2.19, 2.03, 0.38 and 0.54, respectively, and P < 0.05. Multiple logistic regression analysis showed that BCG vaccination scar, history of exposure to PTB and schooling all entered the final regression model, with ORs of 0.36, 1.94 and 2.33, respectively.

CONCLUSION

It suggested that BCG vaccination could play a role in the prevention of TB in the servicemen, and history of exposure to PTB was a potential risk factor for TB as well.

[Structural disorder and conformation difference in the organic molecular crystals]

OBJECTIVE

Investigating multiple configuration nature of natural organic molecules through study on atom disorder in crystal state molecules.

METHODS

Three-dimensional determination for four natural organic compound samples by using single crystal X-ray diffraction.

RESULTS

Through disorder analysis on molecules in crystal state, we have found that the disorder of some atoms may cause conformation difference for molecules, bring about multiple conformation in crystal state hence reducing the symmetry of molecules in crystal cells.

CONCLUSIONS

There can be two or three molecules, even two different compounds in an asymmetrical unit of structure cell because of partial disorder or configuration difference in organic molecule crystals.

Ligand binding to the amino-terminal domain of the mGluR4 subtype of metabotropic glutamate receptor

The metabotropic glutamate receptor (mGluR) 4 subtype of metabotropic glutamate receptor is a presynaptic receptor that modulates neurotransmitter release. We have characterized the properties of a truncated, epitope-tagged construct containing part of the extracellular amino-terminal domain of mGluR4. The truncated receptor was secreted into the cell culture medium of transfected human embryonic kidney cells. The oligomeric structure of the soluble truncated receptor was assessed by gel electrophoresis. In the presence of high concentrations of a reducing agent, the truncated receptor migrated as a monomer; at lower concentrations of the reducing agent, only higher molecular weight oligomers were observed. Competition binding experiments using the radiolabeled agonist [3H]L-2-amino-4-phosphonobutyric acid revealed that the rank order of potency of metabotropic ligands at the truncated receptor was similar to that of the full-length membrane-bound receptor. However, the truncated receptor displayed higher affinities for agonists and lower affinities for antagonists compared with the full-length receptor. Deglycosylation produced a shift in the relative molecular weight of the soluble protein from Mr = 71,000 to Mr = 63,000; deglycosylation had no effect on the binding of [3H]L-2-amino-4-phosphonobutyric acid, indicating that the asparagine-linked carbohydrates are not necessary for agonist binding. These results demonstrate that although the primary determinants of ligand binding to mGluR4 are contained within the first 548 amino acids of the receptor, additional amino acids located downstream of this region may influence the affinity of ligands for the binding site.

[Research on the oncogenesis of cervical epithelial cells co-induced by human papillomavirus and human cytomegalovirus]

OBJECTIVE

The carcinogenesis of the human cervical carcinoma is known closely associated with human papillomavirus (HPV). The purpose of this article is to identify whether another sexually transmitted factor, human cytomegalovirus (HCMV) plays as a co-factor role in the carcinogenesis.

METHODS

Human cervical epithelial cells immortalized by HPV16 were transfected with IE gene of HCMV. The condition and efficiency of IE gene were examined.

RESULTS

It was showed that the cervical epithelial cells could be completely transformed into malignant by HPV 16 and IE gene of HCMV and tumor was formed by injecting the transformed cells in nude mice.

CONCLUSION

The co-operation effect of HPV and HCMV auailed the oncogenesis of human cervical carcinoma and moreover, the cellular and molecular biological mechanism was discussed.

Intraocular pressure lowering by S-allylmercaptocysteine in rabbits

The purpose of this study was to examine the actions of a garlic-derived compound, S-allylmercaptocysteine (SAMC) on intraocular pressure (IOP) and to determine the possible involvement of sulfhydryl reactivity, sympathetic neuronal activity and atrial natriuretic peptide (ANP) in the IOP response. Topical, unilateral application of SAMC (20, 100, 200 microg) elicited dose-dependent decreases in IOP. The magnitude of the IOP-lowering effect induced by SAMC was between four to six mmHg. The ocular hypotensive responses were unilateral, peaked at one to three hours and lasted from two to four hours. The IOP-lowering effect by SAMC (100 microg) was enhanced modestly by topical, bilateral pretreatment with a reducing agent, tris(2-carboxyethyl) phosphine (100 microg) which itself produced no change in IOP. No alteration of pupil diameter was observed following topical application of either SAMC or tris(2-carboxyethyl) phosphine. Thus, alteration of sulfhydryl reactivity does not seem to be a major mechanism of action for SAMC. SAMC caused no change of basal and electrically stimulated norepinephrine release in rabbit iris-ciliary bodies, ruling out a prejunctional effect on sympathetic nerve activity. However, SAMC increased the ANP levels in aqueous humor by five-fold. It is concluded that the ocular hypotensive response induced by SAMC in rabbits could involve the elevation of ANP levels in aqueous humor.

No beneficial effects of isocolloidoosmotic synthetic colloid addition to St. Thomas Hospital cardioplegic solution in ischemia-reperfusion injury in isolated perfused rat hearts

1. Cardioplegic solutions provide the opportunity to operate on a nonbeating heart and to protect the heart against ischemic injury during cardiac surgery. The components of these solutions are constantly being modified in an effort to find the optimal solution. We studied the effects of colloidal volume replacers such as dextran, HES and gelatin as an isocolloidoosmotic addition to St. Thomas Hospital cardioplegic solution in ischemia-reperfusion injury of isolated rat hearts. 2. In the control group, after a stabilization period of 20 min, the hearts were arrested with St. Thomas Hospital cardioplegic solution for 3 min, then subjected to 30 min of global ischemia. Hearts then were reperfused for 10 min. In the experimental groups, the protocol was the same, but either HES 200/0.5 (50 g/L), modified fluid gelatin (30 g/l) or dextran 70 (25 g/L) were added to the St. Thomas Hospital solution. 3. All hearts were compared for their preischemic and postischemic contractility, heart rate, contractility rate product, coronary flow, lactate dehydrogenase, creatine phosphokinase enzyme leakage and wet/dry weight ratio. 4. All groups had similar contractility (for control, HES, gelatin and dextran groups the values at minute 10 of reperfusion were 59+/-9, 56+/-11%, 61+/-14%, 49+/-14% of initial values [P>0.05, respectively]) and enzyme leakage (lactate dehydrogenase 4.1+/-1.0, 8.1+/-1.5, 5.8+/-1.4, 3.7+/-1.2 [P>0.05] and for creatine phosphokinase 3.9+/-2.5, 6.4+/-3.7, 5.5+/-1.3, 5.5+/-0.8, P>0.05] IU xmin(-1) x g dry tissue(-1) in the reperfusion period, respectively) results as compared with the control group. 5. The addition of isocolloidoosmotic colloids to the cardioplegic solution did not appear to enhance the effectiveness of the crystalloid St. Thomas Hospital cardioplegic solution. If a colloid is to be chosen as a plasma replacer or an additive to priming solution in the preoperative period, or during open-heart surgery, it should be modified fluid gelatin-for no sign of cardiodepression was determined with the use of this agent.

Integrin-dependent homotypic adhesion of neutrophils. Arachidonic acid activates Raf-1/Mek/Erk via a 5-lipoxygenase- dependent pathway

AA stimulates integrin-dependent neutrophil adhesion, a critical early step in acute inflammation. However, neither the signaling pathway(s) of AA-stimulated adhesion, nor whether AA acts directly or through the generation of active metabolites, has been elucidated. Previously, we have observed a tight association between neutrophil Erk activation and homotypic adhesion in response to chemoattractants acting through G protein-linked receptors. We now report a similar association between homotypic adhesion and Erk activation in response to AA. Erk activation was cyclooxygenase independent and required AA metabolism to 5(S)- hydroperoxyeicosatetraenoic acid (5-HpETE) via 5-lipoxygenase, but not the further lipoxygenase-dependent metabolism of 5-HpETE to leukotrienes. AA stimulation of Erk was accompanied by Raf-1 activation and was sensitive to inhibitors of Raf-1 and Mek. Whereas activation of Erk by AA was pertussis toxin sensitive, [3H]-AA binding to neutrophils was not saturable, suggesting that an AA metabolite activates a G protein. Consistent with this hypothesis, Erk activation by 5(S)-hydroxyeicosatetraenoic acid (5-HETE; lipoxygenase-independent metabolite of 5-HpETE) was also pertussis toxin sensitive. These data suggest that a 5-lipoxygenase metabolite of AA, e.g., 5-HETE, is released from AA-treated cells to engage a plasma membrane-associated, pertussis toxin-sensitive, G protein-linked receptor, leading to activation of Erk and adhesion via the Raf-1/Mek signal transduction pathway.

[The sensitivity of carcinogenic initiation effect of regenerated liver induced by diethylnitrosamine in rats]

OBJECTIVE

To compare the sensitivity of carcinogenic initiation effect of regenerated liver with normal liver induced by diethylnitrosamine (DEN) in rats.

METHODS

Experimental group was composed of rats that had 2/3 of their liver excised 8 weeks previously, normal rats were used as controls to study: (1) weight of their livers, conventional histological examination and 3H-TdR incorporation test; (2) a modified Solt-Farber carcinogenesis scheme was applied in order to detect the degree of carcinogenic initiation effect by stereologic study of GGT positive preneoplastic liver cell foci; (3) damage of DNA in hepatocytes were detected by in situ nick translation test after DEN treatment both in vivo and in primary cultured liver cells.

RESULTS

(1) the regenerative process in liver was completed by the end of the 8th post-operative week and no proliferation of hepatocytes was detected. (2) both the number and volume density of GGT positive foci in the experimental group were higher than those in control group. (3) DNA damage in hepatocytes of experimental group were more severe than in the control group.

CONCLUSION

Even after the regeneration process was completed, the regenerated liver still possessed higher sensitivity to carcinogenic initiation effect than normal liver, this sensitivity was related with the severity of DNA damage in hepatocytes of the regenerated liver after DEN attack.

[Chemical studies on Campylotropis hirtella (Franch. Schindl.)]

From the roots of Campylotropis hirtella 6 compounds were isolated. Based on the extensive spectrae analysis their chemical structures were identified as beta-sitosterol, oleanolic acid, ursolic acid, euscaphic acid, tomentic acid and rosamultin.

Clinicopathologic manifestations of Epstein-Barr virus-associated cutaneous lymphoproliferative disorders

OBJECTIVE

To elucidate clinicopathologic manifestations of cutaneous lymphoproliferative disorders associated with Epstein-Barr virus (EBV) infection.

DESIGN

Retrospective survey of case series.

SETTING

University hospital medical center.

PATIENTS

Sixty-five patients with cutaneous lymphomas and related disorders.

MAIN OUTCOME MEASURES

Detection of EBV genes and EBV-encoded small nuclear RNAs.

RESULTS

Evidence of latent EBV infection was demonstrated in 15 patients: 3 had malignant lymphoma with clinical features mimicking cytophagic histiocytic panniculitis, 6 had facial vesiculopapular eruptions mimicking hydroa vacciniforme, 4 had angiocentric lymphoma, 1 had histiocytoid lymphoma associated with hemophagocytosis, and 1 had plasmacytoma. Hypersensitivity to mosquito bites was noted in a patient with hydroa vacciniforme-like eruptions and another with histiocytoid lymphoma. Angiocentric infiltration of atypical lymphoid cells was a common histological feature in the patients with hydroa vacciniforme-like eruptions and angiocentric lymphoma. No evidence of EBV infection was apparent in 19 patients with mycosis fungoides or Sézary syndrome, 7 with adult T-cell leukemia or lymphoma, 3 with lymphomatoid papulosis (type A), and 2 with lymphocytoma cutis.

CONCLUSION

Patients with EBV-associated cutaneous lymphoproliferative disorders present with unique and diagnostic clinicopathologic features distinct from those of mycosis fungoides or Sézary syndrome.

Antiplatelet effects of R,S-(meso)-alpha, alpha'-bis[3-(N,N-diethylcarbamoyl) piperidino]-p-xylene ex vivo in the dog and in vivo in the mouse

1. The nipecotamide alpha,alpha'-bis[3-(N,N-diethylcarbamoyl)piperidino]-p-xylene (A-1) is a platelet aggregation inhibitor. The meso diastereomer A-1c is superior in potency and duration to the synthetic diastereomeric mixture consisting of the R,R-, S,S-, and R,S- (meso) isomers in inhibiting collagen-induced platelet aggregation ex vivo in the dog. 2. A-1c also is more potent and longer acting than A-1 in protecting mice from collagen+epinephrine-induced thromboembolic death. 3. The mechanism of antiplatelet action of this compound appears to be related to its ability to prevent agonist-induced inhibition of platelet cyclic adenosine monophosphate (cAMP) levels.

[Quantitative analysis of organophosphorous pesticide residues in Chinese drugs]

This paper reports the GC determination of 13 organophosphorous pesticides in Chinese drugs Flos Ionicerae and Moluodan etc by the present method of Japan for determining pesticide residues. The results suggest that the determined samples do not contain the above said 13 organophosphorous pesticides.

[Quantitative analysis of organochlorine pesticide residues in Chinese drugs]

This paper reports the GC determination of 20 organochlorine pesticides in Chinese drugs Flos Ionicerae and Moluodan etc by the present method of Japan for determinaing pesticide residues. The results suggest that except Folium Isatidis, Radix Codonopsis and Sanqi Pian all accord with the for provisions pesticide residues in Japanese foodstuffs.

Pharmacology of N,N-di(n-butyl)adriamycin-14-valerate in the rat

Lipophilic N-alkylanthracyclines such as AD 198 (N-benzyladriamycin-14-valerate) or AD 201 [N,N-di(n-propyl)adriamycin-14-valerate], which exert their cytotoxicity through mechanisms which are not yet fully defined, possess inherent abilities to circumvent multidrug resistance in vitro and in vivo, possibly though alterations in normal intracellular drug trafficking. As part of structure-activity studies with this class of agent, we have now examined the pharmacology of AD 202 [N,N-di(n-butyl)adriamycin-14-valerate], another analog possessing superior antitumor activity to doxorubicin in vivo and an ability to circumvent multidrug resistance in vitro. Following the administration of AD 202 (20 mg/kg, i.v.) to anesthetized rats, rapid drug distribution (T1/2 5 min) was followed by more gradual elimination (T1/2 3.6h). Plasma clearance of AD 202 (224 +/- 63.6 ml/min per kg) and steady state volume of distribution (25.7 +/- 11.1 l/kg) were indicative of extensive tissue sequestration and/or a large degree of extra-hepatic metabolism. The parent drug predominated in plasma until 20 min, thereafter N,N-di(n-butyl)adriamycin became the principal circulating anthracycline. The systemic exposure to this biotransformation product (area under the plasma concentration-time curve from time zero to 480 min AUC(0-480) 28 1672 ng.min/ml) was > tenfold higher than for the other detected plasma products (N-butyladriamycin-14-valerate, N-butyladriamycin, and three unidentified fluorescent signals; P1-3). Total urinary elimination over 8h was limited (1.9% of dose), occurring predominantly as N,N-di(n-butyl)adriamycin (1.2% of dose), N-butyladriamycin (0.4% of dose), and their corresponding 13-carbinol metabolites (<0.1% of dose each). Low levels of adriamycin (ADR), aglycones and two unidentified products were also seen. Parental AD 202 was found in urine only up to 1h. By contrast, hepatic elimination of parent drug was seen, albeit at low levels, through 8h. Excretion by this route (22% of dose) occurred principally as N-butyl-adriamycin (8% of dose), N-butyladraimycinol (2.1% of dose) with lower levels of N,N-di(n-butyl)adriamycin (1.6% of dose), N,N-di(n-butyl)adriamycin (0.8% of dose), and aglycones (4.3% of dose, combined). Other products included ADR (1.1% of dose) and two unidentified signals (3.4% of dose, combined). The relatively poor mass balance in these studies is attributed to prolonged intracellular retention (elimination T1/2 24.2h) of N,N-di(n-butyl)adriamycin. Thus, in common with other N-alkylanthracyclines, the pharmacology of AD 202 is complex but its therapeutic properties clearly are not derived from an ADR prodrug effect. Significant differences continue to be noted as to the metabolic fate of congeners of this class of anthracycline analogs.

In vivo assessment of nonlinear myocardial deformation using finite element analysis and three-dimensional echocardiographic reconstruction

In vitro data have shown that the myocardium exhibits nonlinear passive stress-strain relationship and a non-linear pressure-volume relationship. A finite element (FE) analysis and optimization algorithm was used on three-dimensional reconstructed left ventricular (LV) geometry using echocardiographic images, along with hemodynamic measurements, in seven closed-chest dogs to show a nonlinear stress-strain relationship in vivo. Our analysis included the computation of Poisson's ratio from the measured volumetric strain of the myocardium and a simulated pericardial pressure load ("equivalent pericardial pressure") applied to the epicardial surface of the reconstructed LV. LV geometry was reconstructed in three or four incremental time steps in diastasis and the myocardium was assumed to be homogeneous, isotropic, and linearly elastic during these short intervals in this initial study. Simultaneous LV chamber pressure and equivalent pericardial pressure were incorporated into the algorithm to predict actual LV expansion. Computations were performed iteratively at each interval to compute the optimized elastic modulus. By performing the FE analysis and optimization at each interval (a step-wise linear analysis approach), a linear relationship between the myocardial elastic modulus and LV chamber pressure was derived (r = .87 to .98). Such a linear relationship is equivalent to an exponential myocardial stress-strain relationship in vivo. Detailed measurement of nonhomogeneous regional deformation are becoming possible with the advent of sophisticated imaging techniques. The methodology described in this study, with appropriate modifications in the FE analysis and optimization algorithms, can be applied to assess the complex three-dimensional pressure-deformation characteristics in vivo.

Enhanced potency of 9-cis versus all-trans-retinoic acid to induce the differentiation of human neuroblastoma cells

All-trans-retinoic acid (ATRA) has been shown to be one of the most potent chemical inducers of human neuroblastoma differentiation. The recent discovery that the stereoisomer of ATRA, 9-cis-retinoic acid (9-cis-RA), binds to both the retinoic acid and retinoid X series of receptors prompted us to evaluate the ability of this compound to promote differentiation of this cell type. Using the LA-N-5 cell line, we have now determined that 9-cis-RA can induce the differentiation of human neuroblastoma cells as evidenced by dose-dependent inhibition of cell proliferation, neurite outgrowth, increased acetylcholinesterase activity, and reduction of N-myc mRNA expression. In comparing the effects of 9-cis-RA to ATRA, we found that while both compounds induced qualitatively similar cholinergic (versus adrenergic) features in LA-N-5 cells, 9-cis-RA was 5-to-10-fold more potent than ATRA in its antiproliferative and differentiation activity. These results were supported by transient transfection experiments utilizing chloramphenicol acetyltransferase (CAT) plasmid constructs containing a retinoic acid responsive regulatory element which showed a 2-to-3-fold increase in reporter gene activity induced with 9-cis-RA over that seen with ATRA at pharmacologically relevant retinoid concentrations (> 10(-8) M). Furthermore, we have determined that 9-cis-RA can significantly enhance mRNA levels of the nuclear retinoic acid receptors alpha and beta in LA-N-5 cells. Taken together, these findings have established the ability of 9-cis-RA to induce neuroblastoma differentiation and suggest that this retinoic acid isomer may have better therapeutic characteristics than ATRA.

Phenylacetate synergizes with retinoic acid in inducing the differentiation of human neuroblastoma cells

Phenylacetate, a natural metabolite of phenylalanine which was originally described as a plant growth hormone, has recently gained attention as a possible differentiation inducer for a variety of human tumor cell types. This interest prompted us to assess the ability of sodium phenylacetate (NaPA) to promote the differentiation of human neuroblastoma cells, both alone and in combination with retinoic acid (RA), a known inducer of neuroblastoma differentiation and maturation. Using the LA-N-5 cell line, we have determined that NaPA can stimulate the differentiation of neuroblastoma cells, as evidenced by dose-dependent inhibition of cell proliferation, neurite outgrowth, increased acetylcholinesterase activity and reduction of N-myc expression. Furthermore, NaPA and RA synergized in inducing differentiation, in that combination treatment resulted in cessation of cell growth along with morphologic and biochemical changes indicative of the loss of malignant properties. We have determined that NaPA can markedly enhance mRNA levels of the nuclear RA receptor-beta (RAR beta) in LA-N-5 cells prior to morphologic or other phenotypic changes induced by this compound. This effect appeared to be distinct from the ability of NaPA to alter tumor cell lipid metabolism via inhibition of protein isoprenylation. Thus among its varied effects on LA-N-5 cells, NaPA appears to interact with the RA pathway at the nuclear level by up-regulating RAR beta expression.

[Biologically active lignins from Magnolia biondii Pamp]

Guided by PAF induced platelet aggregation, six active lignins were isolated from the flower buds of Magnolia biondii and identified as fargesin, demethoxyaschantin, aschantin, pinoresinol dimethyl ether, magnolin, lirioresinol-B dimethyl ether. The 13CNMR and CD data were reported and the configurations were determined.

[Biomechanics of bone in experimental diabetic rats]

The biomechanics of bone in diabetics and its response to insulin treatment was not clear. We investigated the impact of alloxan-induced diabetes and insulin treatment on the biomechanical characteristics of bones. Sprague-Dawley rats were divided into three groups: normal control (NC), diabetics (DM), and diabetics treated with insulin (DI). After 3 months the rats were killed. The load at bending test of the femurs was significantly decreased in DM compared to NC and DI. There was no statistical difference between DI and NC. Structurally, DM was significantly lower than NC and DI in the stress at the proportional limit and the maximum load of vertebrae. In material properties, marked deteriorations in the vertebrae were observed in DM and DI. The plasticity of the vertebrae observed in NC disappeared in DM, in which fragility was obvious. DI was not different from DM. We found that the structure and the material property of the bones deteriorate significantly in diabetes induced by alloxan. Insulin treatment inhibits most of biomechanical changes in bone induced by experimental diabetes, but not all of them. The data suggests that the relations between insulin and the material properties of diabetic bones remain to be studied.

Comparative observation on effect of electric acupuncture of neiguan (P 6) at chen time versus xu time on left ventricular function in patients with coronary heart disease

Paired experimental design was adopted in this experiment for comparative observation on effect of electric acupuncture (EA) of Neiguan (P 6) at Chen Time (7 a.m. to 9 a.m.) versus Xu Time (7 p.m. to 9 p.m.) on left ventricular function in patients with coronary heart disease (CHD). The results show that EA performed at Chen Time could improve the left ventricular function of CHD patients as indicated by shortening of PEPI and decrease of PEPI/LVETI ratio; on the contrary, EA performed at Xu Time prolonged PEPI and raised PEPI/LVETI ratio in CHD patients, suggesting impairment of left ventricular function.

Synergistic antiplatelet effects of a nipecotamide A-1C and low dose aspirin

1. The effects of an antithrombotic nipecotamide, A-1, and aspirin were examined separately and in combination, on human platelet aggregation in vitro and on collagen+epinephrine-induced thromboembolic death of mice in vivo. 2. Concurrent addition of the two agents to a platelet suspension resulted in a supraadditive inhibition. Racemic A-1 and its meso diastereomer A-1C behaved similarly in this respect. The IC50 value of rac. A-1 declined from 46.25 to 18.4 microM in the presence of aspirin. 3. In vivo, concurrent administration of A-1C and aspirin produced significant potentiation of antithrombotic activity. A 2-fold reduction in the ED50 of A-1C occurred when it was coadministered with aspirin to mice; also, the toxicity reduced slightly, increasing the therapeutic index by a factor of 2.2. 4. The design and synthesis of new compounds possessing the structural features of the two molecules appears to provide superior antithrombotic agents.

Modification of catalytic properties of chicken liver fructose 1,6-bisphosphatase by allicin

The activity of chicken liver fructose 1,6-bisphosphatase increases dramatically after incubation with allicin, a major biologically active compound produced by garlic. Activation is more pronounced when the enzyme is assayed with Mn2+ than Mg2+. Maximum activation is accompanied by the disappearance of 4 highly reactive sulfhydryl groups per molecule of enzyme. This modification also leads to loss of activation by K+, and reduced sensitivity to inhibition by AMP, fructose 2,6-bisphosphate, and high concentration of fructose 1,6-bisphosphate. All the altered properties induced by allicin can be reversed by dithiothreitol or tris(2-carboxyethyl)phosphine, the latter being much more effective.

Enantioselective antiplatelet actions of nipecotamides

Two synthetic racemic nipecotamides, 1-decyl-3-(N,N- diethylcarbamoyl)piperidine hydrobromide (1) and alpha, alpha'-bis[3-(N-benzyl-N-methylcarbamoyl)piperidino]-p-xylene dihydrobromide (2) were resolved on a chiral alpha 1-acid glycoprotein semipreparative HPLC column. Thus, rac.1 was resolved into two enantiomers 1A-(+) and 1B-(-); rac.2 was separated into the optical antipodes 2A-(-) and 2C-(+), and the meso diastereomer 2B-(0). Also on a preparative scale, 97% pure 2C was obtained via diastereomeric salt formation using dibenzoyl-L-(-)-tartaric acid. The individual isomers were evaluated for their platelet aggregation inhibitory potency. In inhibiting ADP-induced aggregation of human platelets in vitro, 1B-(-) was 4 times more potent than its optical antipode 1A-(+), and 2C-(+) was 6 times as active as 2A-(-); the meso diastereomer 2B-(0) had intermediate activity. With collagen as the 1B-(-) was twice as active as 1A-(+), and 2C-(+), the most active compound in this series (IC50 = 0.96 microM), was 10 times more potent than its antipode 2A-(-). Again, the meso diastereomer 2B-(0) had intermediate activity. These results demonstrate the enantioselective antiplatelet actions of mono- and bis- nipecotamide derivatives.

Chiral separation of nipecotic acid amides

1-Decyl-3-(N,N-diethylcarbamoyl)piperidine (1) and alpha,alpha'-bis[3-(N-benzyl-N-methylcarbamoyl)piperidinol]-p-xyle ne (2) represent mono-N-substituted and bis-N-substituted carbamoylpiperidines, or nipecotic acid amides, respectively. Initially, several attempts were made to resolve these compounds using beta-cyclodextrin, cellulose carbamate and Pirkle-type columns. However, the interactions of the stereoisomers of the two compounds with these stationary phases did not differ enough to permit satisfactory separations. Baseline resolution was achieved using an alpha 1-acid glycoprotein (AGP) chiral column. The mobile phase was phosphate buffer (pH 7.0). Tetrabutylammonium (TBA) was used as the cationic modifier and ethanol as the uncharged modifier. Circular dichroism was used to identify the enantiomers. Compound 1 was resolved into positive and negative enantiomers and 2 into positive and negative enantiomers and a meso diastereomer. The influence of pH, buffer ionic strength, cationic and uncharged modifier concentrations on retention, chiral selectivity and resolution were evaluated. Based on the results, it is suggested that both ionic and hydrophobic interactions may be responsible for retention and resolution.

Finite-element analysis of arterial anastomoses with vein, Dacron and PTFE grafts

A finite-element simulation of an end-to-end artery/graft anastomosis has been presented in this study to evaluate the distribution of compliance and stresses in the vicinity of the anastomosis due to any mismatch in compliance characteristics. The arterial wall was assumed to be made of linear isotropic elastic material in this simplified model and a static analysis was performed with a mean arterial pressure loading of the artery-graft model. Anastomoses to vein grafts and both Dacron and polytetrafluoroethylene (PTFE) grafts were studied. The results suggested the presence of a hypercompliant zone on the arterial side and a region of high tensile stresses in the wall on the graft side of the anastomosis. The presence of a hypercompliant zone has been reported from previous in vivo studies. The hypercompliance was larger with Dacron and PTFE grafts compared with that with the vein graft. However, larger tensile stresses were present in the wall of the vein graft compared with the synthetic grafts. The analysis further showed that increasing the diameter of the graft compared with the host artery to increase flow through the implant will result in a significant increase in the hypercompliance on the arterial side. Such simulation studies may prove valuable in studying the effects of compliance mismatch and suggest ways to improve the design of small diameter vascular grafts.

Evidence for heat-stable liver cytosol substance(s) capable of causing oxidative activation of fructose 1,6-bisphosphatase

The endogenous fructose 1,6-bisphosphatase (FBPase) in chicken liver extract undergoes a drastic increase in activity if the pH of the extract is in the alkaline range. Greater and more consistent activation occurs when purified FBPase, placed inside dialysis sack, is incubated in liver extract. Maximal activation (over 16-fold) is accompanied by the disappearance of 4 highly reactive sulfhydryl groups (SH) per molecule of enzyme. The activating effect of the extract remains essentially unchanged after heating to 100 degrees C. Activation can be reversed by dithiothreitol. These data show the existence in liver cytosol of heat-stable substance(s) capable of activating FBPase presumably by forming disulfide bonds with the enzyme's highly reactive SH groups.

[Quality standard of kaixiong shunqi pills]

This paper adds TLC identification of binglang and other three cruds drugs to the quality control of kakxiong shunqi pills incorporated in Chinese Pharmacopoeia. The contents of magnolol and honokinol were determined by TLC scanning. The method is simple, rapid accurate, and useful in controlling the quality of kaixiong shunqi pills.

[Determination of glycyrrhetinic acid in radix Glycyrrhizae by TLC densitometry]

A TLC densitometric method for the determination of glycyrrhetinic acid in Radix Glycyrrhizae is described. The method is accurate, sensitive and simple. The recovery of glycyrrhetinic acid is 98.30% and the coefficient of variation of five samplings is 2.20%.

Stress distribution on the cusps of a polyurethane trileaflet heart valve prosthesis in the closed position

In this paper, a finite element analysis of the stress distribution on the cusps of a polyurethane trileaflet heart valve prosthesis in the closed position is presented. The geometry of the valve was modified from a relationship proposed by Ghista and Reul (J. Biomechanics 10, 313-324, 1977). The effects of variations in stent height, leaflet thickness and coaptation area on the stress distribution were also analyzed. Analyses were performed with both rigid and flexible stents for the trileaflet valve in order to delineate the effect of stent flexibility on the leaflet stress distribution. The results showed that regions of stress concentration were present near the commissural attachment similar to those predicted with the bioprostheses. The stresses on the leaflets were reduced by increasing the stent height with both rigid and flexible stents. Selectively increasing the leaflet thickness near the commissures and also increasing the coaptation area did not prove to reduce the leaflet stresses when the stent flexibility was taken into account. The possible effect of high stresses on the structural integrity of polyurethane leaflets and its relationship with calcification is yet to be investigated.

[Determination of tangshenoside I in Codonopsis pilosula Nannf. by TLC-UV spectrophotometric method]

A method of thin layer chromatographic separation and ultraviolet spectrophotometric determination of tangshenoside I in Codonopsis pilosula is described. A comparison of the contents in various samples is made. The contents of tangshenoside I in frosted sample have been found to be twice as much as in normal drug. The recovery of tangshenoside I is 99.92% and the coefficient of variation of eight samplings is 1.77%.

[Chemical constituents of Codonopsis pilosula Nannf]

An exclusive constituent has been isolated from the water soluble parts of root of Codonopsis pilosula for the first time. The constituent has been confirmed to be tangshenosid I.

Activation of chicken liver fructose- 1,6-bisphosphatase by oxidized glutathione

Treatment of chicken liver fructose- 1,6-bisphosphatase with oxidized glutathione (GSSG) leads to an increase in activity. This activation is markedly enhanced if treatment is performed in the presence of AMP or Mn2+. The effects of AMP and Mn2+ appear to be synergistic. The maximal activation is over 13-fold and is accompanied by the disappearance of 4 sulfhydryl groups per molecule of enzyme. Both fructose 1,6-bisphosphate and fructose 2,6-bisphosphate can largely prevent this activation. Activation can be reversed by dithiothreitol or cysteine. It appears that GSSG activates this enzyme by thiol/disulfide exchanges with the enzyme's specific sulfhydryl groups.

Changes in lung hyaluronidase activity associated with lung growth, injury and repair

We measured lung hyaluronidase activity in rats during postnatal life and during the repair of oxygen-induced lung injury. Hyaluronidase activity increased rapidly after birth and peaked at 16-fold the initial value at 8 days. The peak preceded decreased cell proliferation and the onset of differentiation; this is consistent with current concepts of the role of hyaluronidase. During the repair of lung injury, hyaluronidase activity increased to 2.5-fold the control value at 1 day post-injury, but had decreased by 3 days. This early peak is probably related to simultaneous cell proliferation and differentiation. We postulate that changes in hyaluronidase can influence lung growth and repair and that the system may be amenable to manipulation.