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Biomedical subjects

L M Patt

Publications and source records attributed to L M Patt.

At least 19 recordsLinked to original sources
PubMed1995

Inhibition of the human immunodeficiency virus-1 protease and human immunodeficiency virus-1 replication by bathocuproine disulfonic acid Cu1+.

The protease encoded by the human immunodeficiency virus-1 (HIV-1) is essential for processing viral polyproteins which contain the enzymes and structural proteins required for the infectious virus. It was previously found that cupric chloride, in the presence of dithiothreitol or ascorbic acid, could inhibit the HIV-1 protease. It was suggested that a Cu1+ chelate was the moiety responsible for inhibition of the protease. This hypothesis has now been investigated directly by utilizing the stable Cu1+ chelate, bathocuproine disulfonic acid Cu1+ (BCDS-Cu1+). BCDS-Cu1+ inhibited the HIV-1 wild type protease as well as a mutant HIV-1 protease lacking cysteines. BCDS-Cu1+ was a competitive inhibitor of the mutant HIV-1 protease with an apparent Ki of 1 microM. Replication of HIV-1 in human lymphocytes and the cytotoxic effect of HIV-1 in CEM cells was inhibited by micromolar BCDS-Cu1+. Inhibition of the protease and of HIV replication by BCDS-Cu1+ was dependent on the presence of Cu1+ as BCDS alone was ineffective. EDTA blocked the inhibition of the protease by Cu1+ but was unable to block inhibition of the protease by BCDS-Cu1+, indicating that the Cu1+ complex was the inhibitory agent. The apparent IC50 for BCDS-Cu1+ on the inhibition of replication by primary isolates of HIV-1 was 5 microM. However, BCDS-Cu1+ did not affect polyprotein processing in an H9 cell line chronically infected with HIV-1, indicating that BCDS-Cu1+ acts by yet another mechanism to block HIV infection. Other possible targets for BCDS-Cu1+ include inhibition of viral adsorption and/or inhibition of the HIV-1 integrase.

Antiviral Agents↗
PubMed1993

In vivo stimulation of connective tissue accumulation by the tripeptide-copper complex glycyl-L-histidyl-L-lysine-Cu2+ in rat experimental wounds.

The tripeptide-copper complex glycyl-L-histidyl-L-lysine-Cu2+ (GHK-Cu) was first described as a growth factor for differentiated cells. Recent in vitro data showed that it possesses several properties of a potential activator of wound repair. We investigated the effects of GHK-Cu in vivo, using the wound chamber model described previously (Schilling, J.A., W. Joel, and M.T. Shurley, 1959. Surgery [St. Louis]. 46:702-710). Stainless steel wire mesh cylinders were implanted subcutaneously on the back of rats. The animals were divided into groups that received sequential injections into the wound chamber of either saline (control group) or various concentrations of GHK-Cu. At the end of the experiments, rats were killed, wound chambers were collected, and their content was analyzed for dry weight, total proteins, collagen, DNA, elastin, glycosaminoglycans, and specific mRNAs for collagens and TGF beta. In the GHK-Cu-injected wound chambers, a concentration-dependent increase of dry weight, DNA, total protein, collagen, and glycosaminoglycan contents was found. The stimulation of collagen synthesis was twice that of noncollagen proteins. Type I and type III collagen mRNAs were increased but not TGF beta mRNAs. An increase of the relative amount of dermatan sulfate was also found. A control tripeptide, L-glutamyl-L-histidyl-L-proline, had no significant effect. These results demonstrate that GHK-Cu is able to increase extracellular matrix accumulation in wounds in vivo.

Animals↗
PubMed1987

Nuclear peptides from calf liver: large scale isolation and fractionation; control of gene expression in cell-free systems, and inhibition of growth of cells in culture.

DNA and nuclear RNA fractions contain small peptides (mol. wt. 600-1500) attached noncovalently. A large scale isolation procedure was developed for the extraction of such peptides directly from the lysed nuclei. Further purification and fractionation was performed with the chromatography on Sephadex, silica gel and H.P.L.C. C18 reverse phase columns. H.P.L.C. fractionation yielded eleven peaks. The peptides are rich in serine, glycine, alanine and acidic amino acids. They do not contain sulfur-containing amino acids. Only occasionally tyrosine, phenyalanine, histidine, arginine, and very moderate amount of lysine are found. These peptides are active in inhibiting gene expression in cell-free systems and incorporation of labeled thymidine in L 1210 murine leukemic cell culture. Thorough and exhaustive analysis demonstrated that the isolated peptides are not degradative products of histone or nonhistone chromosomal proteins.

Amino Acids↗
PubMed1985

Opposing effects of the polycation hexadimethrine (polybrene) on normal and leukemic lymphocytes.

The polycationic compound hexadimethrine has opposing effects on normal and leukemic murine lymphocytes. This polycation significantly stimulated the DNA-synthetic response of murine spleen cells to alloantigens, whereas, at the same concentration, proliferation of the leukemic cell line, L1210, was inhibited. Other polycations tested did not show this effect. The hexadimethrine had no significant effect on the rejection rate of histoincompatible skin grafts in mice. Low concentrations did inhibit the growth of the L1210 leukemia cells in DBA/2J mice.

Animals↗
PubMed1985

Small peptides bound to polysomal RNA inhibit gene expression in cell-free systems, replication of stimulated lymphocytes and DNA repair in isolated chromatin.

Polysomal poly(A)+-RNA prepared from isolated calf liver polysomes by deproteinization and affinity chromatography on oligo(dT)-Sepharose at pH 6 contains low molecular weight peptides (between 600-1500 daltons) bound noncovalently. These peptides were extracted from the poly(A)+-RNA-peptides complex by precipitation of the nucleic acids with 80% (v/v) ethanol at alkaline pH (9.5) and purified on Sephadex G-25 and G-15 columns. Further fractionation was performed by silica gel chromatography and high performance liquid chromatography (h.p.l.c.). The amino acid composition of the isolated peptidic fraction was compared with similar peptides obtained from rat liver, rabbit reticulocyte and calf thymus polysomes. Effluent (ribosomal) RNA contains only negligible amount of peptides. Isolated polysomal RNA peptides were named "deprimerones" (from Latin "deprimere"), since they have a general depressing effect on gene expression in vitro (Hillar & Przyjemski, 1979). Isolated deprimerones not only inhibit DNA transcription, RNA translation in reconstituted cell-free systems, but also DNA replication by DNA polymerase beta with single- and double-stranded DNA template and synthetic deoxyribonucleotide polymers. The inhibitory effect on replication was correlated with the inhibition of [3H]-deoxyribonucleotide incorporation in isolated chromatin and in stimulated lymphocyte cell cultures. The isolated deprimerones are characterized by similar amino acid compositions in various species.

Amino Acids↗
PubMed1985

Nuclear peptides from calf liver: large scale isolation and fractionation; control of gene expression in cell-free systems, and inhibition of growth of cells in culture.

DNA and nuclear RNA fractions contain small peptides (mol. wt. 600 - 1500) attached noncovalently. A large scale isolation procedure was developed for the extraction of such peptides directly from the lysed nuclei. Further purification and fractionation was performed with the chromatography on Sephadex, silica gel and h.p.l.c. C18 reverse phase columns. H.p.l.c. fractionation yielded eleven peaks. The peptides are rich in serine, glycine, alanine and acidic amino acids. They do not contain sulphur-containing amino acids. Only occasionally tyrosine, phenylalanine, histidine, arginine, and very moderate amount of lysine are found. These peptides are active in inhibiting gene expression in cell-free systems and incorporation of labeled thymidine in L 1210 murine leukemic cell culture. Thorough and exhaustive analysis demonstrated that the isolated peptides are not degradative products of histone or nonhistone chromosomal proteins.

Amino Acids↗
PubMed1983

Role of polypeptide growth factors in normal and abnormal growth.

In the preceding sections we have shown evidence that growth-promoting factors are involved in three basic situations. In normal embryonic development and function of mature organisms, growth factors such as NGF and EGF are of prime importance in supporting the necessary embryonic cell proliferation and the development of specific cell types. Other factors operate on subsets of mature cells during specialized functions such as inflammation. Included in this set would be factors such as CSF/MGF and Interleukin-2. Another basic function of growth factors has been shown to be wound repair and organ regeneration. This includes the well characterized PDGF and FGF as well as the various renotropic factors and liver growth factors. As these factors must operate in mature organisms with many different cell types and similar cell types in many locations, more specificity is needed than in embryonic growth. This has resulted in the organ specific factors such as the renotropins and in the unique delivery system of the PDGF. The recent discovery and characterization of the transforming growth factors has provided a possible connection between embryonic and normal developmental growth and the rapid cellular proliferation characteristic of tumor cells. The TGF not only interacts with receptors for normal growth factors such as EGF but are also detectable in low levels in normal tissue and embryos. The exact relationships between these various factors will have to await the determinations of more amino acid sequences for comparisons. The other tumor-related product, tumor angiogenesis factor, is also found in normal tissue and inflammatory reaction sites.(ABSTRACT TRUNCATED AT 250 WORDS)

Angiogenesis Inducing Agents↗
PubMed1983

Inhibition of lymphocyte transformation by a factor from Pseudomonas aeruginosa.

Extracts of the bacteria Pseudomonas aeruginosa contain a specific inhibitor of lymphocyte transformation. Considerable purification of this inhibitor was possible by a) smashing the bacteria with glass beads, and b) extracting the soluble components with phosphate buffered saline, c) partial purification with ethanol fractionation, d) ion-exchange column chromatography (DEAE-Sephacel) and e) final purification by elution from Ultrogel. The inhibitor was active at a concentration of approximately 10 ng/ml in inhibiting two-way mixed lymphocyte culture of histoincompatible murine splenic lymphocytes in vitro. The inhibitor was also capable of suppressing the proliferation of the murine leukaemic cell line L1210.

Animals↗
PubMed1982

Inhibition of lymphocyte DNA-synthetic responses by spermine-derived polycations.

The polyamines putrescine, spermidine, and spermine are oxidized by the enzyme diamine oxidase to form the corresponding aldehyde derivatives. These aldehydes have been shown to undergo a variety of spontaneous reactions, some of which result in polycationic addition compounds. We have chemically synthesized some spermine-derived polycations by reaction with the dialdehyde glutaraldehyde followed by reduction of te resulting Schiff base with sodium borohydride. Their migration on ion exchange and gel filtration columns was consistent with the formation of polycations with properties similar to those reported for the spontaneous reaction products. When added to cultures of alloantigen or mitogen stimulated lymphocytes, these polycations were potent inhibitors of the incorporation of tritiated thymidine and blast cell formation. This inhibition was reversible, non-cytotoxic, and only apparent if the polycation was added early in the culture period. The concentration of polycation necessary to achieve 50% inhibition of the lymphocyte response decreased as the cationic nature relative to spermine increased.

Animals↗
PubMed1982

Biological specificity of low molecular weight inhibitors of lymphocyte transformation.

Extracts of calf thymus have been shown to contain a number of inhibitors of lymphocyte transformation. A low molecular weight (600 daltons) anionic inhibitor of lymphocyte transformation has been identified and separated from contaminating polyamines and nucleotides. The active fraction inhibited the DNA synthetic response of murine or human T cells to alloantigens in mixed lymphocyte culture and to T-cell-specific mitogens. It was inactive against stimulation of B lymphocytes and several cultured tumor cell lines.

Animals↗
PubMed1981

Pulmonary polyamine permeability factor.

Acid extracts of calf lung have been found to contain low-molecular-weight factors which increase the permeability of the microcirculation when injected into the skin of rats. These factors, which were present in very low levels in aqueous extracts, were purified by gel filtration and ion-exchange chromatography. High-voltage paper electrophoresis revealed two active compounds with mobilities identical to the polyamines spermine and spermidine. Authentic samples of these compounds were as active in the "blueing" reaction as the isolated compounds. The permeability activity of both the isolated factors and the synthetic ones was inhibited by pepstatin and by pretreatment of the animals with pyrilamine maleate. If the normally low extracellular levels of these polyamines is increased by tissue damage, they could increase vascular permeability within the lung by releasing histamine from adjacent mast cells.

Animals↗
PubMed1981

Abnormal behavior of polyamines on gel filtration: a cautionary note.

The polyamines, spermine and spermidine, have been shown to persist in various tissue extracts despite procedures such as dialysis and ultrafiltration which normally remove such low molecular weight compounds. We have found that polyamines in tissue extracts and the standard compounds alone can migrate as much higher molecular weight compounds on gel filtration under a variety of conditions. Thus, even relatively pure fractions obtained from tissue extracts may be contaminated with, or consist entirely of, polyamines, which are potent inhibitors of cell proliferation under certain conditions.

Chromatography, Gel↗
PubMed1981

Low molecular weight inhibitors of lymphocyte transformation.

A variety of factors isolated from bovine thymus have been found to inhibit the transformation of human and mouse lymphocytes. The majority of this activity fractionates as low molecular weight material by ultrafiltration or column chromatography. Three distinct fractions of low molecular weight have been isolated. One fraction contains the polyamines spermine and spermidine. A second fraction contains thymidine or thymidine-like nucleotides. The third fraction appears to be polypeptide in nature, and gives an estimated molecular weight of 500--600, is heat and pH stable, and is easily extracted by solutions containing organic solvents. Preliminary steps in the isolation of this inhibitor are presented, and its relationship to other immunosuppressive and anti-mitotic agents is discussed.

Animals↗
PubMed1980

Notes on improved procedures for the chemical modification and degradation of glycosphingolipids.

Some simplified and efficient procedures are described for the following chemical modifications of glycophingolipids. 1) The olefinic bond of the ceramide moiety of the acetylated glycolipid was quantitatively oxidized with osmium tetroxide and periodic acid. Treatment of the resulting glycolipid aldehyde with sodium methodixe resulted in the release of the intact oligosaccharide. The yield of oligosaccharides under the new conditions was much higher than previously found. 2) The olefinic bond was also oxidized to a carboxyl function by either of two methods: a) the aldehyde group resulting from the above oxidation was further oxidized with performic acid; and b) the olefinic bond of the fully acetylated glycolipid was oxidized directly to the acid by potassium permanganate in acetone. 3) The methyl ester of the carboxyl group of the sialic acid in gangliosides can be formed with diazomethane in methanol-ether after treatment of the gangliosides with Dowex-50 (H+ form). Possible uses of these glycolipid modifications are discussed.

Chemistry, Organic↗