The formation of constants of mercury(II)--glutathione complexes

The formation constants of the 1:1 and 1:2 complexes of Hg(II) with glutathione and their protonated species have been determined by using a competitive potentiometric titration with the competing ligand diethylenetriaminepentaacetic acid (DTPA). The formation constants of the 1:1 complex and its protonated species have not been reported previously. The formation constant of the 1:2 complex of Hg(II) and glutathione is substantially smaller than the accepted values that has been reported in the literature. These results have important implications in the models that have been employed to explain the mobilization and distribution of Hg(II) in biological systems.

Cigarette smoking among Chinese adolescents and its association with demographic characteristics, social activities, and problem behaviors

The rate and pattern of cigarette smoking were assessed using data collected in 1991 from 1,040 6th, 8th, and 10th grade youth in Beijing, People's Republic of China. One-fifth of the youth reported having ever smoked cigarettes. The rate of smoking appears to increase with advancing age and is associated with poorer academic performance and participation in unstructured activities and other problem behaviors. In contrast to data from European and United States youth, smoking is significantly more prevalent among males (29%) than among females (11%, p < .0001). The data underscore the need for smoking-prevention programs targeting Chinese early adolescents.

Fiber-optic distributed sensing by a two-loop Sagnac interferometer

A two-loop Sagnac interferometer is proposed for fiber-optic distributed sensing. The location of a disturbance can be determined from the two output phase signals of the two Sagnac loops, and the amplitude of the disturbance can be obtained by integration of the phase signal. A prototype distributed impact sensing system has been tested based on the two-loop Sagnac interferometer.

Comparison of rac- and meso-2,3-dimercaptosuccinic acids for chelation of mercury and cadmium using chemical speciation models

The formation constants of various mercury and cadmium chelates of the stereoisomers of 2,3-dimercaptosuccinic acid (DMSA) have been determined from potentiometric titrations in the presence of the competing ligand EDTA. The mercury chelates formed at pH 7.4 are the monomeric HgL of the DMSA diastereoisomers and HHgL2 of rac-DMSA. Mercury is completely complexes at pH greater than 3.0 in solutions containing more than 1 equiv of either rac- or meso-DMSA. At high concentrations (10 microM and above) mercury tends to bind to a greater extent to rac- than to meso-DMSA. At pH 7.4, the predominant cadmium meso-DMSA chelate species in solution is CdL, and HCdL is present at a much smaller concentration. With rac-DMSA, however, the predominant cadmium chelate species is HCdL at a low concentration of the ligand, and at a high concentration of the ligand the species CdL2 predominates. Cadmium is completely chelated at pH 7.4 in solutions containing more than 1 equiv of either rac- or meso-DMSA. At pH around 5.5, which corresponds to the pH of the kidney, however, a significant amount of free cadmium is present in solutions containing 1 equiv or less of either DMSA stereoisomer. From the results of an analysis of speciation models, probable kidney damage, that may result from free cadmium ion release in the kidney during chelation therapy, is inferred when meso-DMSA is used for mobilizing cadmium. In contrast, the release of free cadmium ion is negligible in the pH range in the kidney when rac-DMSA is used. On the basis of the speciation models, rac-DMSA is found to be far superior to meso-DMSA in the treatment of acute cadmium poisoning.

Similarity of risk and protective behaviors among African-American pre- and early adolescent members of naturally occurring friendship groups

To determine whether self-reported risk and protective behaviors, expectations, and attitudes are more similar among African-American early adolescents within a community-based friendship group than across groups, a cross-sectional study was conducted among 382 African-American youth 9 through 15 years of age forming 76 community-based groups of 3 through 10 same-gender friends. Each member of the friendship group reported his/her own past involvement in nine risk behaviors (sexual intercourse, substance abuse, drug-trafficking, and other delinquent activities) and two protective behaviors (high academic performance and regular church attendance) and their expectations and feelings regarding several of these behaviors. Intraclass correlation coefficients were calculated overall and by gender and age. Members were generally more similar within friendship groups than across groups with regard to several risk behaviors and expectations including sexual intercourse and drug-trafficking. Particularly striking was the similarity among members of "junior" friendship groups (e.g., median age of youth < 11 years) of both risk and protective behaviors and expectations. The finding of enhanced similarity of risk behaviors and expectations among members within groups suggests that intervention delivery through community-based friendship groups may be a useful approach for risk prevention efforts targeting pre-adolescent African-American youth living in low-income settings.

Polarization-independent all-fiber wavelength-division multiplexer based on a Sagnac interferometer

An all-fiber wavelength-division multiplexer (WDM) based on the nonreciprocity of the birefringence to the polarization states is proposed. The transfer function of a Sagnac interferometer is wavelength dependent if the loop birefringence of the interferometer consists of both circular and linear parts. Theoretical analysis shows that the output characteristics of this WDM are similar to those of a fiber taper-based device. Both the bandwidth and the peak wavelength of the new WDM can be tuned by changing the loop birefringence. Experimental prototypes exhibit a channel isolation greater than 25 dB with peak passband insertion loss of less than 1 dB.

An improved method for determination of acid dissociation constants of peptides

PURPOSE

The method described here enables the proton dissociation constants of several amino acid residues of a peptide to be determined simultaneously in aqueous solution without prior knowledge of the exact concentration of the peptide.

METHODS

The method used here employs a non-linear fitting program, the BEST program, or a linear least-squares method in combination with the BEST program. These methods are discussed in detail with an emphasis on the quality of the potentiometric titration data that are obtained. Two representative peptides, one with two proton dissociation constants (Ka1, Ka2) and the other with four proton dissociation constants (Ka1-Ka4) were used to illustrate the advantages and the limitations of these two complementary methods.

RESULTS

The pKa values of TVL, a schizophrenia-related tripeptide, were found to be 3.62 (+/- 0.02) and 7.17 (+/- 0.05); the pKa values of ELTLQE, a hexapeptide, were found to be 2.32, 3.77, 4.58 and 7.74.

CONCLUSIONS

The methods reported here are generally applicable to a variety of peptides. The possibility of integrating these procedures into a preparative chromatographic system for the "on-line" assessment of the pKa values of peptides during the purification stage is an attractive and novel feature of this method.

Generation and reactions of the disulphide radical anion derived from metallothionein: a pulse radiolytic study

OH-radicals were generated by pulse radiolysis of aqueous solutions of rabbit (Zn,Cd)-metallothionein (MT). They react with MT mainly by forming a thiyl radical with a rate constant of 1.7 x 10(12) dm3 mol-1 s-1. The thiyl radical reacts rapidly but reversibly with a thiolate function to form RSSR.-: RS + RS- reversible RSSR.-. The kinetics of the formation and decay of this radical anion have been studied pulse radiolytically by monitoring the evolution of the optical absorption of RSSR.- at 450 nm. This process is mostly intermolecular, i.e. bimolecular in MT. In the absence of O2, RSSR.- decays bimolecularly: RSSR.(-)+RS.-->RSSR + RS-. In the presence of O2, RS. may be scavenged by O2 and thus the yield of RSSR.- decreases: RS.+O2 reversible RSOO.. Under these conditions RSSR.- decays by first-order kinetics: RSSR.(-)+O2-->RSSR + O2.-. The rate constants of these reactions have been determined at room temperature: k4 = 1.8 x 10(9) dm3 mol-1 s-1, k5 = 7 x 10(4) s-1, k10 = 9.2 x 10(8) dm3 mol-1 s-1, and k18 about 3 x 10(7) dm3 mol-1 s-1. From the dependence of the maximal absorbance at 450 nm on the thiolate concentration in the absence of oxygen, epsilon (RSSR.-) = 9 x 10(3) dm3 mol-1 cm-1 and the stability constant (K4/5) of 2.3 x 10(4) dm3 ml-1 was determined. K4/5 is in good agreement with that determined kinetically, k4/k5 = 2.6 x 10(4) dm3 mol-1. The stability constant K15/16 of the thiylperoxyl radical, RSOO., was determined to be 5.5 x 10(3) dm3 mol-1.

Epoxyeicosatrienoic acid metabolism in arterial smooth muscle cells

Epoxyeicosatrienoic acids (EETs) are eicosanoids synthesized from arachidonic acid by the cytochrome P450 eposygenase pathway. The present studies demonstrate that 8,9-, 11,12-, and 14,15-EET are rapidly taken up by porcine aortic smooth muscle cells. About half of the uptake is incorporated into phospholipids, and saponification indicates that most of this remains in the form of EET. The EETs also are converted to the corresponding dihydroxyeicosatrienoic acids (DHETs) and during prolonged incubations, additional metabolites that do not retain the EET carboxyl group are formed. Most of these products are released into the medium. However, some DHET and metabolites less polar than EET are incorporated into the phospholipids, and a small amount of unesterified EET is also present in the cells. The incorporation of 14,15-EET and its conversion to DHET did not approach saturation until the concentration exceeded 10-20 microM, indicating that vascular smooth muscle has a large capacity to utilize this EET. These findings suggest that certain vasoactive effects of EETs may be due to their incorporation by smooth muscle cells. Furthermore, through conversion to DHET and other oxidized metabolites, smooth muscle apparently has the capacity to inactivate EETs that are either formed in or penetrate into the vascular wall.

Stereoisomeric selectivity of 2,3-dimercaptosuccinic acids in chelation therapy for lead poisoning

The formation constants of lead chelates of the stereoisomers of 2,3-dimercaptosuccinic acid (DMSA) were determined from potentiometric titrations in the presence of the competing ligand, EDTA. The lead chelates formed at pH 7.4 with the stereoisomers of DMSA are the monomeric complexes PbL and HPbL. Formation of PbL and HPbL at pH 7.4 is independent of total concentrations of lead and DMSA present, and so is the concentration ratio of PbL:HPbL. Lead is completely chelated at pH 7.4 when the total concentration of ligand is equal to or greater than the total concentration of lead present. Lead tends to bind to a greater extent with rac- than with meso-DMSA, and the relative extent increases with an increase in the concentration ratio of ligand to lead and finally reaches a constant value of 45. The binding sites in the chelates, PbL, of the stereoisomers of DMSA are the two thiolate groups and one carboxylate group. rac-DMSA also forms a dimeric complex Pb2L2 in which both carboxylate groups of the ligands participate in binding with lead ions. The formation constants of the lead chelates of rac-DMSA were invariably found to be larger than those of the corresponding of meso-DMSA chelates, because in all the lead chelates of the stereoisomers of DMSA formed in solution, rac-DMSA existed in staggered anti conformations, whereas meso-DMSA preferred a staggered gauche conformation with respect to carboxylate groups in the ligands. The potential of using ZnL2 of rac-DMSA as a therapeutical lead chelator was assessed by considering its lead-mobilizing ability and its ability to deplete endogenous zinc; on this basis it is predicted that ZnL2 of rac-DMSA is a better chelator than meso-DMSA for the treatment of lead poisoning.

[Chemical constituents in the leaves of Mangifera persiciformis C.Y. Wu et Y.L. Ming]

Eleven crystalline constituents have been isolated from the leaves of Mangifera persiciformis, of which five were identified as taraxerol, friedelin, beta-sitosterol, mangiferin and quercetin by comparing their physicochemical and spectroscopic data. They were isolated from this plant for the first time.

[Clinical characteristics of hepatic tuberculosis]

The clinical characteristics of hepatic tuberculosis in 52 cases diagnosed pathologically were analyzed. Fever, abdominal pain and hepatomegaly were the major clinical manifestations; they were present in 96.2%, 42.3% and 88.5% of the patients respectively. The fever had no consistent pattern and the abdominal pain was usually localized to the right hypochondrium and not related to overwork. Hypergrammaglobulinaemia, elevated alkaline phosphatase level and increased ESR were noted in most of the patients (76.9%, 75.0%, 76.5% respectively). 62.5% of the 52 patients was diagnosed by percutaneous liver biopsy. Since there is no consistent clinical pattern in patients with hepatic tuberculosis, the diagnosis should be considered in patients with unexplained fever associated especially with hepatomegaly or hepatosplenomegaly, elevated alkaline phosphatase level, hypergrammaglobulinaemia and increased ESR, Liver biopsy is the most valuable method to confirm the diagnosis of hepatic tuberculosis.

Conformations of zinc chelates of meso- and rac-2,3-dimercaptosuccinic acid in aqueous solution

rac-2,3-Dimercaptosuccinic acid (DMSA) was found to be superior to meso-2,3-dimercaptosuccinc acid in mobilizing in vivo heavy metals such as Cd, Hg, and Pb. The disadvantage of using rac-DMSA alone as a clinical antidote for heavy metal poisoning is that it causes a greater loss of endogenous zinc than its meso isomer. The difference between the two diastereoisomers of DMSA in the excretion of endogenous zinc has been rationalized on the basis of the differences in the conformations of their zinc complexes. The zinc complexes of rac-DMSA in aqueous solution are more stable than the corresponding complexes of its meso isomer because the rac-DMSA ligands always adopt staggered anti conformations, in which the electrostatic repulsion between two bulky carboxylate groups is minimized; in contrast, unlike in the crystal lattice, meso-DMSA ligands always adopt staggered gauche conformations in their zinc complexes. The conformations of various monomeric and dimeric zinc complexes with rac- and meso-2,3-dimercaptosuccinic acid in aqueous solution were determined by IR spectroscopy and proton NMR spectroscopy as a function of zinc:ligand ratio, by proton NMR spectroscopy as a function of pD, and by variable-temperature 13C NMR spectroscopy. rac-DMSA in ZnL2(6-) coordinates with zinc ion via two thiolate groups and one carboxylate group, whereas in Zn2L2(4-) each ligand complexes two zinc ions by using one carboxylate group and one thiolate group in the beta-position to bind to the same zinc ion.(ABSTRACT TRUNCATED AT 250 WORDS)

A comparative study of meso- and rac-2,3-dimercaptosuccinic acids and their zinc complexes in aqueous solution

The conformations of meso-2,3-dimercaptosuccinic acid (meso-DMSA) in aqueous solution have been postulated from proton NMR titrations. The complexes formed with zinc(II) and the ligands rac-DMSA and meso-DMSA have been postulated from potentiometric titrations of solutions containing varying ratios of zinc:ligand. The complex formation behavior of rac-DMSA with zinc(II) is dramatically different from that of meso-DMSA. These differences are reflected in the complex formation constants of the zinc(II) species and their distributions in solution as a function of zinc:ligand ratios and as a function of pH. On the basis of these results we have predicted that rac-DMSA is more effective than meso-DMSA in mobilizing lead in vivo and that the 1:2 zinc complex of rac-DMSA can be used effectively for the treatment of heavy metal poisoning because endogenous zinc will not be depleted by this chelation treatment.

The region encompassing the procyclic acidic repetitive protein (PARP) gene promoter plays a role in plasmid DNA replication in Trypanosoma brucei

We have previously reported the construction and characterization of an autonomously replicating plasmid in Trypanosoma brucei. In this plasmid the procyclic acidic repetitive protein (PARP) gene promoter drives the transcription of a selectable marker. Deletion of this promoter incapacitates the plasmid, suggesting its utilization as a promoter-trap. Three independent libraries were created by inserting variously digested T.brucei genomic DNA into this promoterless construct. Transfection of these libraries into procyclic T.brucei and the subsequent isolation of episomes led only to the reisolation of the PARP promoter. Additionally, a ribosomal RNA promoter failed to keep the construct as an episome, although it can sustain mRNA transcription in T.brucei and was shown to be an efficient promoter in this construct. Finally, by using a transient replication assay involving the methylation-sensitive restriction endonuclease DpnI to distinguish between input and replicated DNA, we showed that the PARP promoter-bearing construct could replicate autonomously in procyclic T.brucei, but the corresponding construct with the rRNA promoter could not. The close association between elements that sustain transcription and DNA replication in T.brucei mirrors results observed in several higher eukaryotes and their viruses and suggests an ancient origin of this feature.

Purity control of different bee venom melittin preparations by capillary zone electrophoresis

A rapid capillary zone electrophoresis method was developed for the determination of melittin during its purification from bee venom by column chromatography. Low-pH buffer was selected to decrease the adsorption of the analytes on capillary wall. The average relative standard deviations of the migration time of melittin and of the peak area were 1.2 and 2.3%, respectively.

Preformulation studies with melanotan-II: a potential skin cancer chemopreventive peptide

Melanotan-II (1) is a cyclic heptapeptide analogue of alpha-melanocyte-stimulating hormone (alpha-MSH) which tans the skin and is currently being evaluated for the prevention of sunlight-induced skin cancers. The dissociation constants of 1 were determined using potentiometric titration and ultraviolet spectrophotometry. The pKa1 (histidine) and pKa2 (arginine) were estimated to be 6.54 and 11.72, respectively. The apparent partition coefficient (PC) was measured at three pH values using both n-octanol and isooctane as the nonpolar phase. The PC(octanol) and delta log PC at pH 7.35 were 2.82 and 1.05, respectively. These data, together with the observance of a bioavailability of 4.6% in the rat, indicate that 1 may be a suitable candidate for oral delivery. The data presented here are useful in developing an appropriate dosage form for 1.

Radiolysis of metallothionein in deaerated and oxygen-saturated solutions

Gamma radiolysis of metallothionein (MT) in phosphate-buffered solutions at pH 8.0 leads to the formation of intra- and intermolecular disulfide bridges as well as the release of chelated metal ions. When MT solutions deaerated with N2 or saturated with N2O were irradiated, G values for RS- loss as determined by Ellman's reagent were 4.2 and 7.0, respectively, whereas those for dimerization were only 0.32 and 0.67. A short chain reaction existed in the decrease in RS- when radiolysis was performed in O2-saturated solutions. The rate constants for reactions of MTs with OH radical and H2O2 were measured to be about 10(12) and 100 M-1 s-1, respectively. A mechanism for the radiolysis of MT-1 is proposed.

High-efficiency gene transfer and high-level expression of wild-type p53 in human lung cancer cells mediated by recombinant adenovirus

A replication-defective and helper-independent recombinant p53 adenovirus was generated. The virus, Ad5CMV-p53, carries an expression cassette that contains human cytomegalovirus E1 promoter, human wild-type p53 cDNA, and SV40 early polyadenylation signal. Four human non-small-cell lung cancer cell lines representing differences in p53 configuration were used to evaluate the Ad5CMV-p53 virus. In the H358 cell line, which has a homozygous deletion of p53, the p53 gene was transferred with 97% to 100% efficiency, as detected by immunohistochemical analysis, when the cells were infected with Ad5CMV-p53 at a multiplicity of infection of 30 to 50 plaque-forming units/cell. Western blots showed that the p53 protein was expressed at a high level. The protein expression peaked at day 3 after infection and lasted for at least 15 days. Growth of the Ad5CMV-p53 virus-infected H358 cells was inhibited 79%, whereas that of noninfected cells or the cells infected with the control virus was not inhibited. Growth of cell line H322, which has a point mutation in p53, was inhibited 72% by Ad5CMV-p53, while that of cell line H460 containing wild-type p53 was less affected (28% inhibition). Tests in nude mice demonstrated that tumorigenicity of the Ad5CMV-p53-treated H358 cells was greatly inhibited. In a mouse model of orthotopic human lung cancer, the tumorigenic H226Br cells, with a point mutation in p53, were inoculated intratracheally 3 days before the virus treatment. Intratracheal instillation of Ad5CMV-p53 prevented tumor formation.(ABSTRACT TRUNCATED AT 250 WORDS)

Synthesis, structure, and properties of rac-2,3-dimercaptosuccinic acid, a potentially useful chelating agent for toxic metals

rac-2,3-Dimercaptosuccinic acid (rac-DMSA) may be a more effective antidote for the treatment of heavy metal poisoning than meso-2,3-dimercaptosuccinic acid (meso-DMSA), which is used at present. A comparative study of these two chelating agents has been undertaken in order to investigate this possibility. The structures of rac-DMSA and the precursor in its synthesis, rac-2,3-bis(acetylthio)succinic acid, have been determined by single-crystal X-ray analysis and compared with the structures of the corresponding meso compounds. The concentration distributions of the various ionic and molecular species of rac-DMSA that are present in aqueous solutions in the pH range 1.8-12.8 have been calculated from the four acid dissociation constants that have been determined potentiometrically at an ionic strength of 0.10. The conformations of these species in aqueous solutions have been determined by 1H NMR spectroscopy as a function of pH. The rac-DMSA exists in the crystal lattice as a double-stranded structure in which each molecule is in a gauche configuration. The meso-DMSA, however, exists in a single strand in which each molecule has adopted an anti configuration and the individual molecules are joined together at each end by hydrogen bonds. These differences in the conformations of rac- and meso-DMSA may account for the significant difference in the solubilities of the two compounds in aqueous solutions. In acidic solutions at elevated temperatures of about 95 degrees C, rac-DMSA is slowly but irreversibly converted to meso-DMSA. This conversion does not occur at ambient temperatures.

Generation and identification of recombinant adenovirus by liposome-mediated transfection and PCR analysis

A simplified method for generating recombinant adenovirus was developed by using liposome-mediated co-transfection and by directly observing for the cytopathic effect caused by recombinant adenovirus in transfected 293 cells. This approach avoided difficulties associated with calcium-phosphate precipitation and agarose overlays for plaque assays. The ease of generating recombinant adenovirus was considerably improved. Analysis by PCR of DNA samples from the supernatant of the cell cultures with the cytopathic effect was also developed, which made identification of any newly generated recombinant virus rapid and specific.

Molecular approaches to the diagnosis and treatment of cancer

We have used autologous bone marrow transplantation (ABMT) as a setting to develop the genetic therapy of cancer in hematopoietic neoplasms based on the use of the bone marrow as a conduit through which to introduce regulatory molecules into the patient. This has involved three developmental phases: 1) learning how to develop genetic modification techniques; 2) learning how to develop in vivo selection techniques for the genetically modified cells; and 3) developing molecular vectors for modification of hematopoietic cells for therapy of cancer. These programs will be summarized in terms of their progress at the conference.

A family of erythrocyte binding proteins of malaria parasites

Malaria erythrocyte binding proteins use the Duffy blood group antigen (Plasmodium vivax and Plasmodium knowlesi) and sialic acid (Plasmodium falciparum) on the erythrocyte surface as receptors. We had previously cloned the one P. vivax gene, the one P. falciparum gene, and part of one of the three P. knowlesi genes encoding these erythrocyte binding proteins and described the homology between the P. knowlesi and P. vivax genes. We have completed the cloning and sequencing of the three P. knowlesi genes and identified introns in the P. vivax and P. falciparum genes that correct the previously published deduced amino acid sequences. All have similar structures, with one or two exons encoding the signal sequence and the erythrocyte binding domain, an exon encoding the transmembrane domain, and two exons encoding the cytoplasmic domain with the exception of the P. knowlesi beta gene. The regions of amino acid sequence homology among all the genes are the 5' and 3' cysteine-rich regions of the erythrocyte binding domain. On the basis of gene structure and amino acid homology, we propose that the Duffy binding proteins and the sialic acid binding protein are members of a gene family. The level of conservation (approximately 70%) of the deduced amino acid sequences in the 5' cysteine-rich region between the P. vivax protein and the three P. knowlesi proteins is as great as between the three P. knowlesi proteins themselves; the P. knowlesi beta protein just 3' to this cysteine-rich region is homologous to the P. vivax protein but not to the other P. knowlesi proteins. Conservation of amino acid sequences among these organisms, separated in evolution, may indicate the regions where the adhesin function resides.

Fluorometric labeling of tetrahydroprogesterones

7-Diethylaminocourmarin-3-carbohydrazide was used to label the ketone group of the tetrahydroprogesterones to form fluorescent derivatives with high sensitivity. The four isomeric 3-hydroxypregnanes separated readily on high-performance, thin-layer chromatography after derivatization. This separation was not possible with the underivatized isomers. Standards and steroids from biologic mixtures were separated and showed similar characteristics. The methods used are described.

Synthesis and bioactivities of new LHRH antagonists containing a novel unnatural amino acids at position five

Synthesis and bioactivities of new antagonists of luteinizing hormone releasing hormone (LHRH) with novel unnatural amino acids at position five are reported. Most of them showed some antiovulatory activity at 0.5 microgram/rat and two of them inhibited ovulation completely at 1 microgram/rat using saline as vehicle.

[plants of Coptis from Tibet and Yunnan]

In this paper the relationship of Tibetan Huanglian and Yunnan Huanglian with Coptis teeta has been studied. The distribution and taxonomic features of Tibetan Huanglian are just the same as Coptis teeta, but quite different from Yunnan Huanglian. The results reveal that Tibetan Huanglian and Yunnan Huanglian are different in botanical origin.

Antagonists of luteinizing hormone releasing hormone with novel unnatural amino acids at position six

Five new antagonists of luteinizing hormone releasing hormone (LHRH) containing novel unnatural amino acids at position six are reported. They are very effective in the rat antiovulatory assay. Using saline as vehicle, antagonist-[N-Ac-D-2-Nal1, D-4-Cl-Phe2, D-3-Pal3, Arg5, D-A26, D-Ala10]-LHRH inhibited ovulation completely at 1 micrograms/rat and three of the other antagonists showed some antiovulatory activity at 0.5 micrograms/rat.

[Left ventricular end-systolic pressure-dimension relation and its sensitility to the positive inotropic factor in the anesthetized open-chest dogs]

Left ventricular end-systolic pressure-dimension relation (ESPDR) was generated by the transient occlusion of the inferior vena cava (IVC) or thoracic aorta (AO) in 13 anesthetized open-chest dogs, while the left ventricular pressure was measured by a TP-200T pressure transducer and the anterior-posterior dimension was measured by a pair of ultrasonic crystal implanted in the endocardium and recorded by a Sonomicrometer. The results showed that: (1) the ESPDR was shown to be linear, unaltered by preload or afterload changes; (2) dobutamine produced a significant increase in the slope (Emax) of the ESPDR-IVC and ESPDR-AO relations, without remarkable effect on the dimension-axis intercept (Do). However, the change in Emax was more significant for ESPDR-IVC (174.43 +/- 23.48%, n = 18), as compared with that for the ESPDR-AO (71.02 +/- 12.46%, n = 12); (3) Do of the ESPDR-AO relation was smaller than that of the ESPDR-IVC both under control and during dobulamine infusion. We conclude that the linear ESPDR can be derived in the anesthetized open-chest dogs either by caval occlusion or by aortic occlusion, and the slope appears to reflect left ventricular contractility. However, techniques used to generate the ESPDR may influence results, including the Do and the sensitivity of Emax to the inotropic state.

Peripheral leukocytes in psoriasis

The white blood cell (WBC) count and differential count, including the morphology and acid alpha-naphthyl acetate esterase (ANAE) activity of lymphocytes, in psoriatic patients of different types, stages, and extensiveness of skin lesions were analyzed. The number of total WBC and polymorphonuclear leukocytes was markedly increased in psoriasis erythrodermica and psoriasis pustulosa. Lymphocytopenia, especially T-lymphocytopenia, was noticed in all types of psoriasis. Antineoplastic drugs and immunosuppressants intensified the degree of T-lymphocytopenia. This might be the cause of recurrence and more recalcitrant course of the disease. Therefore, it is considered that these drugs should not be the first choice in the treatment of psoriasis.

Plant Anticancer Agents XXXVII. Constituents of Amanoa oblongifolia1

4'-Demethyldeoxypodophyllotoxin was isolated as the sole cytotoxic constituent of a chloroform-soluble extract of the stem bark of AMANOA OBLONGIFOLIA. Also identified from this extract were a number of noncytotoxic isolates that comprised the lignans, (+)-sesamin and paulownin, the triterpenes, friedelin, canophyllol, betulin, betulinic acid, and ursolic acid, and the sterols, beta-sitosterol and daucosterol.

Plant anticancer agents, XXXIV. Cucurbitacins from Elaeocarpus dolichostylus

Elaeocarpus dolichostylus has afforded the new cucurbitacin derivative, hexanorcucurbitacin F (3), whose structure was determined by spectroscopic and chemical correlation with curcurbitacin F (1). Cucurbitacin F (1) and 23,24-dihydrocucurbitacin F (2) were also isolated in this study.