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Biomedical subjects

R Salomon

Publications and source records attributed to R Salomon.

At least 73 records · Page 4Linked to original sources
PubMed1993

Characterization and distribution of alpha 2-adrenergic receptors in the human intestinal mucosa.

The subtype and the expression of the alpha 2-adrenergic receptor were investigated in the normal mucosa from human intestine by means of radioligand binding, RNase mapping, and measurement of adenylate cyclase activity. The study of the binding of the alpha 2-adrenergic antagonist, [3H]RX821002, to epithelial cell membranes indicated the existence of a single class of noninteracting sites displaying a high affinity for the radioligand (Kd = 1.1 +/- 0.5 nM). The rank order of potency of antagonists to inhibit [3H]RX821002 binding (RX821002 > yohimbine = rauwolscine > phentolamine approximately idazoxan >> chlorpromazine > prazosin) suggested that the receptor is of the alpha 2A subtype. A conclusion which is confirmed by the fact that only alpha 2C10 transcripts were found in the human intestine mucosa. Competition curves with (-)-norepinephrine demonstrated that 60% of the receptor population exhibited high affinity for agonists. This high-affinity state was abolished by the addition of GTP plus Na+ or by prior treatment of the membranes with pertussis toxin indicating it corresponded to G protein-coupled receptors. [32P]ADP-ribosylation and immunoblotting experiments identified two pertussis toxin-sensitive G proteins corresponding to Gi2 and Gi3. The study of the distribution of the receptor indicated that (a) the proximal colon is the intestine segment exhibiting the highest receptor density and (b) the receptor is predominantly expressed in crypts and is preferentially located in the basolateral membrane of the polarized cell. The distribution of the receptor along the crypt-surface axis of the colon mucosa can be correlated with a higher level of alpha 2C10-specific mRNA and a higher efficiency of UK14304 to inhibit adenylate cyclase in crypt cells.

Adenosine Diphosphate Ribose↗
PubMed1990

Involvement of fungi and bacteria in enhanced and nonenhanced biodegradation of carbendazim and other benzimidazole compounds in soil.

The relationship between chemical structure and the enhancement of microbial degradation of three benzimidazole compounds in soil was determined. Preapplication of methyl benzimidazole-2-ylcarbamate (carbendazim or MBC), 2-aminobenzimidazole (2AB), and benzimidazole enhanced their degradation upon repeated application (self-enhanced degradation). MBC and 2AB cross-enhanced the degradation of each of these two compounds, whereas benzimidazole did not enhance the degradation of MBC. Thiabendazole (TBZ) did not enhance its own degradation or cross-enhance the degradation of MBC. No increase in the number of MBC-degrading fungi or in the capacity of soilborne fungi to degrade MBC was detected in soil exhibiting enhanced MBC degradation (MBC-history). A sharp increase in esterolytic activity in the microsomal fraction of Alternaria alternata capable of degrading MBC in culture was induced by the presence of MBC in the growth medium. 2AB was the main metabolite of MBC that accumulated in A. alternata cultures and in cell-free preparations. MBC was degraded much faster by mixed bacterial cultures that originated from MBC-history soil than in cultures from MBC-nonhistory soil. Fluctuations in the MBC degrading capacity of mixed bacterial cultures occurred during repeated subculturing of the mixed culture. Inoculation of nonhistory soil with mixed bacterial cultures resulted in enhanced MBC degradation, whereas inoculation with A. alternata did not enhance MBC degradation. It is suggested that while fungi contribute to MBC dissipation in soil, bacteria have a greater role in enhanced biodegradation of MBC in soil.

Acremonium↗
PubMed1990

From basic concepts to clinical reality. Unresolved issues in the diagnosis of dependence.

This chapter discusses clinical and conceptual issues pertaining to the diagnosis of alcohol and drug dependence. Emphasis is given to the difficulties involved in moving from diagnostic concepts, such as those contained in the major psychiatric classification systems, to the clinical situation where diagnostic decisions are made. To illustrate how diagnostic concepts approximate clinical reality, a set of case histories is used to organize a discussion of unresolved issues in the diagnosis of dependence. These issues include the putative syndrome nature of dependence, the problem of diagnosing polysubstance use, the primary-secondary distinction, the presence of other psychopathology, and the use of multiaxial evaluation.

Adult↗
PubMed1989

Use of monoclonal antibodies in the purification of an inhibitor of virus replication by affinity chromatography.

Mouse monoclonal antibodies (MAbs) were prepared to an inhibitor of virus replication (IVR), released from protoplasts or leaf tissue of hypersensitive tobacco plants infected with tobacco mosaic virus. The MAbs were highly specific for IVR and reduced its antiviral activity. Using these MAbs in affinity chromatography enabled the recovery of purified IVR. SDS-PAGE of the immunoaffinity-purified IVR gave a single Mr 23K band. Immunoblots of IVR from extracts of protoplast or leaf tissue also revealed a single Mr 23K band which suggests that protoplast and tissue IVR are closely related.

Antibodies, Monoclonal↗
PubMed1989

Partial cleavage of sweet potato feathery mottle virus coat protein subunit by an enzyme in extracts of infected symptomless leaves.

The coat protein of particles of sweet potato feathery mottle potyvirus (SPFMV) extracted from Ipomoea spp. migrated in SDS-PAGE mainly as bands of M(r) 38,000 (38K), 36K, 32K, 30K. Trypsin treatment of the particles resulted in the appearance of only one 30K polypeptide. The inclusion of protease inhibitors in the extraction procedure did not alter the heterogeneity of SPFMV coat protein. A partially purified fraction of extracts from recovering, symptomless, but not from healthy leaves of I. nil had a proteolytic activity similar to that of trypsin. Amino acid sequencing showed that the trypsin-cleaved 30K polypeptide had some sequence homology with other potyvirus coat proteins. The site at which the Ipomea extract cleaved the protein was five amino acids nearer the N terminus than trypsin cleavage site.

Amino Acid Sequence↗
PubMed1986

The effect of dormancy on the heat shock response in gladiolus cormels.

Cormels of Gladiolus X gandavensis Van Houtte respond to heat shock by an induced synthesis of heat shock proteins. Synthesis of some of the non-heat shock proteins is concomitantly reduced. The ability of dormant cormels to synthesize heat shock proteins (hsps) and to repress the synthesis of non-hsps is greater than that of nondormant ones. A hsp of apparent molecular weight 68 kilodaltons is synthesized only in dormant cormels or in cormels that lost their dormancy after long storage at 25 degrees C. The synthesis of hsps at 40 degrees C, but not at 25 degrees C, is promoted by abscisic acid in nondormant cormels. Methionine incorporation into hsps declines after a 4-hour incubation period at 40 degrees C. Induction of hsps is stronger if exposure to extreme temperature is done gradually.

Journal Article↗
PubMed1982

Translational competition between related virus RNA species in cell-free systems.

The competition between the RNAs from two tobacco mosaic virus (TMV) strains for translation in rabbit reticulocyte lysate and wheat germ cell-free systems was investigated. The virus translational products were distinguished by the size difference of the I2 polypeptides. The RNAs of the two strains were translated simultaneously if added to the translation system together at the beginning of the reaction. Each of the TMV RNAs could inhibit translation of the other when the reaction was initiated by the RNA of one strain and that of the other strain was added after active translation had commenced. In contrast, translation of alfalfa mosaic virus (AMV) RNA was not appreciably inhibited when its RNA was added after the start of translation of TMV RNA; the addition of TMV RNA to an AMV RNA-initiated reaction also resulted in independent synthesis of the products of both virus RNAs.

Cell-Free System↗
PubMed1976

Abundance of tRNAPhe lacking the peroxy Y-base in mouse neuroblastoma.

Affinity chromatography on anti-Y (Y is a tricyclic imidazopurine to which is attached a complex four-carbon side chain) antibody immobilized to Sepharose was used to determine the proportion of rat liver tRNAPhe species containing the peroxy Y-nucleoside. Unfractionated Unfractionated mammalian tRNA was aminoacylated with labeled phenylalanine. The phenylalanyl-tRNA was then chemically acetylated to yield N-acetylphenylalanyl-tRNA. When this preparation was applied to the antibody column, between 6-10% of the radioactivity was not bound to the column, indicating a deficiency of peroxy Y-nuceloside in a minor isoaccepting tRNAPhe species. In contrast to normal tissues (including embryonic tissue), about 85% of the tRNAPhe from mouse neuroblastoma C-1300 or N-18 tumors lack the peroxy Y-base, a property which is not affected by tumor age. Rat liver labeled N-acetylphenylalanyl-tRNA preparations were resolved on Plaskon chromatography (RPC-5) into two minor peaks closely followed by a mojor component. A high proportion of the two minor tRNAPhe species was unable to bind to anti-Y antibodies. Upon mild acid treatment, the minor and major tRNAPhe species eluted simultaneously from Plaskon columns, at a much reduced salt concentration. These results would indicate that the two minor tRNAPhe species from rat liver as well as the major component contain a tricyclic imidazopurine base that differs from each other in its side chain. About 85% of the N-acetylphenylalanyl-tRNA from neuroblastoma was resolved by Plaskon chromatography as an early eluting peak. The position of this major neuroblastoma tRNAPhe species was not altered by mild acid treatment, and its elution position from the column almost coincides with that of acid-treated normal rat liver tRNAPhe. The latter results would suggest that most of the tRNAPhe chains from neuroblastoma lack the tricyclic imidazopurine of normal rat liver tRNAPhe, but are very close if not identical in primary nucleotide sequence.

Animals↗