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.