[SERS and electrochemistry studies on the structure of thiourea adsorption layer on silver electrode]

The structure of thiourea adsorption layer on silver electrode was studied by SERS and electrochemistry. It was found that the thiourea can be adsorbed on the electrode surface and can inhibit the reaction of hydrogen separation. And a change in structure of the thiourea adsorption layer on electrode surface took place at the voltage of about -0.6V. The further SERS experiment showed that the thiourea adsorption layer has a loose structure at about -0.9V and a compact structure at about -0.3V - -0.5V. The transition region is at about -0.6V - -0.8V.

[Colony-stimulating activities of serum from patients with severe aplastic anemia]

OBJECTIVE

To investigate the correlation between colony-stimulating activities of serum from patients with severe aplastic anemia (SAA) and their responses to immunosuppressive therapy (IST).

METHODS

In vitro effects of sera from SAA patients before and after IST and from normal subjects on human marrow colony growth were examined in a semisolid methylcellulose culture system for burst promoting activity (BPA) and granulocyte/macrophage colony-stimulating activity (GM-CSA). Serum erythropoietin (Epo) level was also measured by ELISA method before and after IST in SAA patients.

RESULTS

Serum BPAs in SAA patients at diagnosis were significantly higher than that in normal controls (P<0.001), but serum GM-CSAs in 13 of 22 SAA patients were normal,and in 9 of 22 extremely low as compared with normal values. After IST, serum BPA and GM-CSA in SAA patients had no changes. Serum Epo levels in SAA patients at diagnosis were significantly higher than that in normal controls (P<0.001). After IST,serum Epo levels declined in responded patients, while further increased in nonresponded.

CONCLUSION

Serum GM-CSA of SAA patients was a predictive factor for responsiveness to IST, and a normal value was associated with a good response.

[HLA-DR-positive T lymphocytes in the bone marrow and peripheral blood of patients with severe aplastic anemia and their in vitro inhibitory effecton BFU-E and CFU-GM]

OBJECTIVE

[corrected] To elucidate the role of immunodysfunction in the pathogenesis of severe aplastic anemia (SAA).

METHODS

HLA-DR+ T cells were detected in bone marrow (BM) and peripheral blood (PB) of 20 SAA patients and controls (9 for BM and 11 for PB). PHA-LYCM conditioned medium was prepared, and its in vitro effect on normal bone marrow BFU-E and CFU-GM was studied.

RESULTS

The percentages of HLA-DR+ T lymphocytes in BM and PB of newly diagnosed SAA patients were significantly higher than that of controls (P<0.001), and that of recovered SAA (rSAA) patients after ALG therapy (P<0.05). Compared with controls, the PBA-LYCMs from newly diagnosed SAA patients showed significant inhibitory effect on normal BFU-E and CFU-GM (P<0.001).

CONCLUSION

The activated T lymphocyte may play an important role in the pathogenesis of SAA.

Chemical modification and structure-activity relationships of pyripyropenes. 3. Synthetic conversion of pyridine-pyrone moiety

Structure-activity relationships of the pyridine-pyrone moiety in pyripyropene A (1), a potent acyl-CoA: cholesterol acyltransferase (ACAT) inhibitor of fungal origin, were studied. Several kinds of aromatic or hetero ring substituents for the pyridine moiety were synthesized using unique degradation reaction, following by gamma-acylation. All the six synthesized analogs decreased the inhibitory activity with 20 to 200 times larger IC50 values than that of 1. Furthermore, the pyridine-pyrone substituent also dramatically decrease the inhibitory activity. Thus, the pyridine-pyrone moiety is important for eliciting potent ACAT inhibition.

[Activating blood circulation and removing stasis in treating polycythemia vera: clinical observation and therapeutical mechanism]

OBJECTIVE

To assess the efficacy of "method of activating blood circulation and removing stasis (ABCRS)" in treating polycythemia vera.

METHODS

28 cases of polycythemia vera were treated with ABCRS and observed with bone marrow colonies.

RESULTS

15 casses were responsibe, of them 4 cases reached clinical remission, 11 cases were improved. Both bone marrow colonies of colony forming unit-erythroid dependent of erythropoietin (EPO + CFU-E) and colonies of CFU-E independent of EPO. (EPO-CFU-E) from these cases decreased significantly, especially the latter. ABCRS mainly suppressed the proliferation and differentiation of EPO-CFU-E. In addition, bone marrow colonies of colony formng unit-fibroblastoids (CFU-F) from these cases also changed obviously.

CONCLUSION

ABCRS is effective in treating polycythemia vera.

[Blocking action of tetrandrine on the cell proliferation induced by PDGF in human lung fibroblasts and liver Ito cell of rats]

OBJECTIVE

To investigate the mechanism of hepatic fiberosis, the effects of platelet-derived growth factor (PDGF) on cell proliferation activity and collagen synthesis in human lung fibroblasts (HLF) and Ito cells of rat liver as well as the blocking action of tetrandrine on the cell proliferation induced by PDGF.

METHODS

The Ito cells were separated from liver of rats by using the perfusion of collagenase and density pradient centrifugation. The cell proliferation was observed with the incorporation method of H-TdR and 3H-L-proline.

RESULTS

Under condition of cell culture with 1% serum, PDGF could significantly enhance DNA synthesis, cell proliferation and collagen synthesis, which increased in degree with a rising of concentration of PDGF. This occurred in culture without serum, but under the same condition, if PDGF was applied together with insulin-like growth factor (IGF), it enhanced cell proliferation. The result also showed that the dose of tetrandrine below the level of inhibiting cell DNA synthesis could antagonize the stimulation action of PDGF on cell proliferation and collagen synthesis.

CONCLUSION

Tetrandrine plays the blocking action in the promoting cell proliferation induced by PDGF.

Chemical modification and structure-activity relationships of pyripyropenes. 1. Modification at the four hydroxyl groups

Four hydroxyl groups of pyripyropenes have been modified and evaluated for their ability to inhibit microsomal acyl-CoA:cholesterol acyltransferase (ACAT) activity in vitro and to lower cholesterol absorption in vivo in a cholesterol-fed hamster. 7-O-n-Valeryl derivative (8c) improved the in vitro ACAT inhibitory activity (IC50 = 13 nM) about 7 times better than pyripyropene A. Introduction of methanesulfonyl group at 11-hydroxyl group (17a) increased both in vitro activity (IC50 = 19 nM) and in vivo efficacy (ED50 = 10 mg/kg).

Enzyme immunoassay of two nicergoline metabolites, 10 alpha-methoxy-9, 10-dihydrolysergol (MDL) and 1-methyl-10 alpha-methoxy-9, 10-dihydrolysergol (MMDL)

Specific and sensitive enzyme immunoassays for two nicergoline metabolites, 10 alpha-methoxy-9, 10-dihydrolysergol (MDL) and 1-methyl-10 alpha-methoxy-9, 10-dihydrolysergol (MMDL) have been developed. The hydroxyl group of hydroxymethyl at position 8 of either MDL or MMDL was carboxymethylated to introduce a carboxyl group for protein conjugation. Antibodies generated from O-carboxymethyl MDL or MMDL recognized the spacer arm between the hapten and the carrier protein and the molecular domain near the conjugation site as well. A heterologous bridge strategy was used to improve the affinity of the hapten-enzyme conjugate to the antibodies. The sensitivity of both assays was greatly increased by using such an approach. Both antibodies are specific for their own haptens. Little cross reactivity was observed with nicergoline and other metabolites. Determination of MDL and MMDL from both spiked plasma and urine showed nearly quantitative recovery. Detection of MDL and MMDL can be as sensitive as 10 pg/ml.

[Stereotactic intratumoral irradiation of huge craniopharyngioma]

Craniopharyngioma, often with cystic diliatation, is difficult to resect radically. Fifty patients with huge craniopharyngioma (diameter of tumor was over 5 cm) treated with intratumoral irradiation of radioactive isotopes (32P and 90Y) through CT-guided Leksell stereotactic system are reported. The patients were 2 to 69 years of age with the disease of 1- to 12-year duration. Of the 50 patients, 21 had recurrent tumor after craniotomy, 29 without surgery operation before. All tumors were confirmed pathologically. The major clinical symptoms were as follows: visual field defect, headache, vomiting, diabetes insipidus, hemiplegia and growth retardation in juvenile cases. There was no death or serious complications following the treatment procedure. Partial response (> 50% reduction of tumor size on CT scanning with improvement of symptoms and signs) rate of the treatment was 82.0% at one month and 62.0% at 2 to 7 years after treatment.

Stereotactic intratumour irradiation with nuclide for craniopharyngiomas

OBJECTIVE

Craniopharyngiomas is a kind of intractable tumor in neurosurgery. Since the radical excision is very difficult and occasionally hazardous because of its deep location and close neighbouring to critical cerebral structures, it is necessary to look for a simple and effective method.

PATIENTS AND METHODS

Stereotactic intratumour irradiation with instillation of nuclide colloid was performed in 220 patients with craniopharyngiomas (altogether 265 times), of whom, 130 were male and 90 female. Their ages ranged from 5 to 69 years. The syndromes of optic path's impairment were present in all of the patients. CT or MRI scan showed cystic tumour in 125 patients, solid and cystic in 80 and solid in 15. No severe complications and death were related to the operation.

RESULTS

150 patients were followed up for 2 months to 7 years (average 3.5 years). Tumours disappeared in 92 patients (61.4%), decreased dramatically in 20 (13.4%), decreased less than 50% in 19 (12.6%), and increased in 15 (10%); and there were 4 deaths (2.6%).

CONCLUSIONS

Stereotactic intratumour irradiation with instillation of nuclide colloid is effective in the patients with craniopharyngiomas. Beta-emitting isotopes (P-32 and Y-90) are the preferred internal radiation source because of their limited penetration of the energy released and the greater ease of handling. A calculated dose of 20 000 rads to the cyst wall is recommended.

[Karyological studies on the fruit of Gardenia jasminoides Ellis]

This paper reports the karyological studies on the fruit of Gardenia jasminoides and G. jasminoides var. grandiflora. The chromosome numbers are 2n = 22 and the places of centromere are metacentric and submedian. The fruit of G. jarminoides is more primary than Gardenia jarminoidce var. grandiflora in karyotype.

Determination of a cyclic guanine monophosphate phosphodiesterase inhibitor (SCH 51866) in rat serum using capillary zone electrophoresis

A capillary zone electrophoretic (CZE) assay was developed for the determination of cis-5,6a,7,8,9,9a-hexahydro-2-[4-(trifluoromethyl)phenylmethyl]-5-methyl - cyclopent[4,5]imidazo[2,1-b]purin-4(3H)-one, SCH 51866 (I), a cyclic guanine monophosphate phosphodiesterase inhibitor, in rat serum using acetonitrile deproteination as a clean-up step before injection. The calibration curve was linear over a serum concentration range of 0.5 to 10 micrograms/ml serum with a correlation coefficient (r) > 0.99. The limit of quantitation (LOQ) was established at 0.5 micrograms/ml. Fifty microliters of serum were used for analysis, which allowed serial bleeding (8 samples) from a single rat to characterize the pharmacokinetic profile of I after either oral or intravenous drug administration. In traditional pharmacokinetic and toxicokinetic studies in rodents, one animal provides only one serum sample since 1 to 2 ml of sample volume is required for chromatographic analysis, resulting in the use of a large number of animals per study. This assay yields a significant reduction in the use of animals, hence providing a large reduction in resources and time in drug discovery and development.

Multiple subpial transection for treatment of intractable epilepsy

On the basis of experimental study, we applied multiple subpial transection (MST) to treat 50 patients with intractable epilepsy in which epileptigenic lesion involved functional areas such as pericentral gyrus, postcentral gyrus, Broca's area, Wernicke's area, visual cortex, etc. They were followed up for 6 to 40 months. Complete control of seizures was obtained in 32 patients, significant reduction of seizure (more than 50%) in 13, reduction (less than 50%) in 3, and no effect in 2. The total effective rate was 96%. No functional defect was found in all patients. The mechanism of the disease and surgical technique were discussed in detail. We consider that MST could replace some standard excisional therapy for local epilepsy.

[Epidemiologic studies on three episodes of acute bacillary dysentery outbreak]

Three episodes of illness outbreak, with major symptoms of acute abdominal pain and diarrhea, occurred in 1990 to 1991 in the army forces stationed in Beijing. Bacillary dysentery outbreak caused by Shigella dysentariae were confirmed with epidemiological investigations and pathogen identification. Drug sensitivity tests with Kirby-Bauer method for the strain isolated showed it had obvious resistance to 13 of 14 kinds of antibiotics tested. Detection of plasmid with Birnboim method showed most of the strains had R-plasmid of 120-140 Md and few had small plasmid. It suggested inherent connection between drug-resistance of the strains and plasmid.

A specific enzyme immunoassay (EIA) with selective extraction for quantitation of a topical anti-inflammatory agent, SCH 40120, in human plasma

SCH 40120 is a potent anti-inflammatory agent under development for the topical treatment of dermal inflammatory and allergic disorders such as atopic dermatitis, contact dermatitis and psoriasis. We have previously described a sensitive enzyme immunoassay (EIA) for SCH 40120 in unextracted human plasma to support clinical studies. However, severe cross-reaction with unknown metabolites was observed during validation using samples from rats dosed with 14C-SCH 40120. Therefore, a selective extraction procedure was developed to remove the unknown plasma metabolites of SCH 40120 prior to EIA quantitation. The modified EIA using extracted plasma was cross-validated with an LC method using plasma samples from dosed subjects (human and rat), thereby confirming the specificity of the assay. The EIA can reliably quantitate SCH 40120 in plasma samples from 100 pg ml-1 to 10 ng ml-1 with good linearity, accuracy and precision, and is suitable for pharmacokinetic studies in man.

Effects of C alpha-methyl substitution on the conformation of linear GnRH antagonist analogs

We have examined the effect of C alpha-methyl groups on the conformational ensemble of GnRH analog peptides by comparing 1H 2D NMR data from two analogs, Ac-D-Nal1-D-4-Cl-C alpha-Me-Phe2-D-Pal3-Ser4-Tyr5-D-Arg6-Leu7-Arg8-Pro9-D-Al a10- NH2 (1) and Ac-D-Nal1-D-4-Cl-C alpha-Me-Phe2-D-Pal3-Ser4-C alpha-Me-Tyr5-D-Arg6- Leu7-C alpha-Me-Arg8-Pro9-D-Ala10-NH2 (2). The two additional C alpha-methyl groups in residues 5 and 8 of 2 do not influence significantly the pattern of the observable main chain NOE intensities, or of the backbone HN proton chemical shifts, which indicates that they do not produce global changes in the conformational ensemble of the peptide. A local change induced by the substitution was observed in the conformation at D-Arg8-Pro9.

[Studies on the constituents of the roots of Acorus calamus L]

A new tricyclic sesquiterpene, named calamenone (1), and two known sesquiterpenes, calamendiol (2) and isocalamendiol (3), were isolated from the roots of Acorus calamus L. The structure of the new compound was elucidated on the basis of spectral and X-ray diffraction data.

A sensitive enzyme immunoassay (EIA) for quantitation of the topical anti-inflammatory agent SCH 40120 in unextracted human plasma

SCH 40120 is a potent acute anti-inflammatory agent under development for topical treatment of dermal inflammatory and allergic disorders such as atopic dermatitis, contact dermatitis and psoriasis. In order to support percutaneous absorption studies, a competitive enzyme immunoassay (EIA) was developed to determine SCH 40120 in unextracted plasma samples. SCH 38280, a carboxylated analogue of SCH 40120, was used as the hapten and conjugated with bovine thyroglobulin (Thy). The hapten-Thy conjugate was used as the immunogen to immunize rabbits for antibody production. The hapten was also coupled to horseradish peroxidase (HRP) to form SCH 38280-HRP, which was used as the tracer. The EIA can detect SCH 40120 concentrations as low as 50 pg ml-1 of plasma, and can reliably quantitate SCH 40120 in plasma samples from 100 pg ml-1 to 10 ng ml-1 with good linearity, accuracy and precision. A variety of structurally related compounds and potential metabolites did not significantly cross-react with the antibodies, except for a few analogues. The availability of this sensitive assay makes it possible to evaluate the pharmacokinetics of SCH 40120 in man.

Synthesis of phosphotyrosine-containing peptides by the solid-phase method. A re-examination of the use of Boc-Tyr(PO3Bzl2)-OH

A practical and convenient procedure for making phosphotyrosine-containing peptides by the solid-phase method was developed. Phosphotyrosine was incorporated via Boc-Tyr(PO3Bzl2)-OH. The completed peptide was cleaved from the solid support by treatment with 1 M TMSBr-thioanisole-TFA. By gel-phase 31P-NMR spectroscopy we found that one of the benzyl protecting groups on phosphate was completely removed by two consecutive runs of Boc deprotection with 50% TFA-DCM. However, the other benzyl group remained intact throughout the synthesis (35 cycles).

Amino- and guanidinoacylryanodines: basic ryanodine esters with enhanced affinity for the sarcoplasmic reticulum Ca(2+)-release channel

Amino- and guanidinoacyl esters of ryanodine were prepared to evaluate the effect of basicity on the binding affinity of these derivatives for the sarcoplasmic reticulum Ca(2+)-release channel (SR CRC). In the presence of DCC and DMAP Cbz-beta-alanine reacts with ryanodine in CH2Cl2 to give O10eq-Cbz-beta-alanylryanodine (3a), which on hydrogenolysis yields the beta-alanyl ester (4a). N,N'-bis-Cbz-S-methylthiourea reacts with 4a to yield beta-N,N'-bis-Cbz-guanidinopropionylryanodine (5a). O10eq-beta-guanidinopropionylryanodine (6a) is obtained on hydrogenolytic deprotection of 5a. The binding affinity of beta-alanine ester (4a) and its glycyl congener (4b) is 2-3-fold greater, and that of the beta-guanidinopropionyl ester (6a) and its acetyl congener (6b) 3-6-fold greater, than that of ryanodine. The effect of ryanodine on SR Ca2+ flux is of a biphasic nature: nanomolar levels open (activate) the channel, while micromolar levels close (deactivate) it. The base-substituted esters 4a and 6a both display a unidirectional effect: they only open the channel. An understanding of ryanodine's mode of action and the design of effective SR CRC activating and deactivating ryanoids for possible therapeutic application are major research objectives.

[Clinical observation of the effect of pretreatment with nifedipine in preventing oxygen free radicals in the cardiopulmonary release bypass operation]

The effect of pretreatment with nifedipine in preventing oxygen free radicals release was observed in the cardiopulmonary bypass (CPB) operation. Twenty cases were divided into two groups for comparison. Nifedipine (0.6 mg/kg) was given to the test group. MDA, XO, UA and SOD were measured. These examinations were taken at pre-aortic clamping, 15 min after aortic clamping, and 30, 60, 120, 180 min after reperfusion. The results indicated that pretreatment with nifedipine reduced oxygen free radicals release in the CPB operation.

Removal of Qa-2 antigen alters the Ped gene phenotype of preimplantation mouse embryos

Embryo survival is influenced by both genetic and environmental factors. Previous research in our laboratory has identified one gene associated with embryonic survival, the Ped gene, a gene that is linked to the major histocompatibility complex (MHC) of the mouse. The Ped gene has been shown to influence the rate of preimplantation embryonic cleavage division, as well as litter size, birth weight, and weaning weight. Genetic mapping of the Ped gene has located it in the Q region of the MHC and has suggested that possible Q region genes encoding the Ped gene are Q3, Q5, Q6, Q7, Q8, and/or Q9. Whereas the protein products of the Q3 and Q5 genes are unknown, the protein product of the very similar Q6, Q7, Q8, and Q9 genes is the Qa-2 antigen. Two forms of membrane-bound Qa-2 antigen are known: glycosylphosphatidylinositol (GPI)-linked and transmembrane bound. Only the GPI-linked form is sensitive to cleavage by phosphatidylinositol phospholipase C (PI-PLC). The first purpose of the present study was to determine the nature of the linkage of the Qa-2 antigen to the cell surface of preimplantation mouse embryos. It was found that all detectable Qa-2 antigen on the embryonic cell surface is sensitive to cleavage by PI-PLC and is therefore bound to the cell membrane by a GPI linkage. Furthermore, removal of Qa-2 antigen from the embryonic cell surface slows down the rate of development of preimplantation mouse embryos. These results suggest the likelihood that the Qa-2 antigen is the Ped gene product.

Synthesis of optically pure C alpha-methyl-arginine

Optically pure L-(+)-C alpha-methyl-arginine and D-(-)-C alpha-methyl-arginine were synthesized. Experimental results indicated that DL-C alpha-methyl-arginine methyl ester could be resolved by trypsin, but workup posed a technical difficulty. Chemical resolution at the stage of DL-C alpha-methyl-ornithine, followed by selective guanidination using N,N'-di-Cbz-S-methylisothiourea and hydrogenolysis provided a effective and practical method for the synthesis of optically pure C alpha-methyl-arginine.

A competitive enzyme immunoassay for the direct determination of mometasone furoate (SCH 32088) in human plasma

Mometasone furoate (SCH 32088) is a synthetic corticosteroid which has a topical anti-inflammatory activity with a minimal potential for suppressing hypothalamic-pituitary-adrenocortical (HPA) axis. A sensitive competitive enzyme immunoassay (EIA) for measuring SCH 32088 in unextracted human plasma has been developed. The 3-(O-carboxymethyl)oxime (CMO) of SCH 32088 was synthesized and conjugated with bovine thyroglobulin, and the product was used for the production of antibodies in rabbits. SCH 32088-3-CMO was also conjugated with horseradish peroxidase, which was used as the tracer. The EIA thus developed can detect 1 pg SCH 32088 per assay or 25 pg per ml of human plasma. It can reliably quantitate SCH 32088 in human plasma from 50 pg ml-1 to 2.5 ng ml-1 with good linearity, accuracy and precision. The assay can be extended to measure SCH 32088 in plasma of laboratory animals. The availability of this sensitive assay makes it possible to evaluate the pharmacokinetics and toxicokinetics of SCH 32088 in laboratory animals and man.