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Biomedical subjects

L Galvan

Publications and source records attributed to L Galvan.

At least 19 recordsLinked to original sources
PubMed1996

Effects of heparin on wound healing.

Heparin, an anticoagulant that is widely used for cardiac patients, has been studied to determine its effects on wound healing. The role of heparin in wound healing has been demonstrated in both in vitro and in vivo studies. In cell culture studies, heparin and growth factors are associated with rapid and effective endothelial cell repair. In clinical studies, patients with burns and those with diabetic foot ulcers showed an increase in capillary circulation and decreased healing time. In contrast, heparin may not be beneficial in populations with ischemia, malnourishment, and vascular problems, although research in these populations is limited. Nevertheless, heparin continues to have therapeutic advantages for wound healing in carefully selected patients.

Anticoagulants↗
PubMed1982

Inhibition of PM-2 DNA degradation by a human serum protein.

A unique DNA-binding protein was detected that inhibited DNA degradation induced by bleomycin and was decreased in sera of cancer patients. The protein from normal human serum was purified to homogeneity by ammonium sulfate precipitation and DEAE-cellulose and DNA-cellulose column chromatography. Two-dimensional isoelectric focusing gel electrophoresis revealed a single protein spot with a molecular weight of 64,000 and a pI at pH 5.9. The NH2 terminus was lysine, and the ratio of acidic to basic residues was 1.2. DNA binding was demonstrated by column chromatography, agarose gel electrophoresis, fluorescence quenching, and circular dichroism. The inhibitory activity was abolished by treatment with Pronase but not by RNase or DNase I. FeCl2 caused a partial loss of inhibitory activity. The inhibition of DNA degradation was more effective for breakage induced by bleomycin than neocarzinostatin, macromomycin, or DNase I. Evidence from DNA-binding studies suggests the inhibition is due to binding of the protein to sites on DNA preferred by bleomycin. Thus, the protein could be useful for studies on the mechanism of action of bleomycin and other antitumor agents, the cytotoxic effects of which are due primarily to damage of cellular DNA. The protein was decreased significantly in sera of cancer patients, and its potential use as a diagnostic tool for neoplasias is being investigated further.

Bleomycin↗
PubMed1982

Detection of a serum DNA-binding protein associated with cancer.

An accompanying report describes the purification and partial characterization of a unique DNA-binding protein (Mr 64,000; pI 5.9) that is present in human sera. This report gives the results of assays of sera from patients for the bleomycin inhibitor protein (BIP) using the Pseudomonas bacteriophage covalently closed circular DNA fluorescence technique standardized for DNA breakage induced by bleomycin. The results of the BIP assays were expressed by values of specific activity of inhibition. One arbitrary unit of inhibitory activity was defined as equivalent to the amount of serum protein required to cause 50% inhibition of DNA degradation using standard conditions of the DNA breakage assay. The mean values of specific activity of inhibition (SAI) for groups of healthy individuals (n = 26), patients with nonmalignant diseases (n = 33), and patients with malignant diseases (n = 83) were 12.60 +/- 4.69 (S.E.), 12.53 +/- 3.17, and 2.40 +/- 0.84 units/mg, respectively. Mean SAI values for patients with cancers of various types were: solid tumors (n = 46), 2.44 +/- 0.86; leukemias (n = 24), 2.59 +/- 0.96; and lymphomas (n = 18), 2.07 +/- 0.64. The decrease in BIP activity was not correlated with sex, age, or prior chemotherapy. Mean SAI values of male (n = 29) and female (n = 59) patients with cancer were 2.61 +/- 0.87 and 2.30 +/- 0.83 units/mg, respectively. Mean SAI values for different age groups were: 0 to 40 years (n = 21), 2.05 +/- 0.68 units/mg; 41 to 70 years (n = 56), 2.59 +/- 0.68 units/mg; and greater than 70 years (n = 11), 2.12 +/- 0.67 units/mg. Cancer patients with and without prior chemotherapy had mean SAI values of 2.97 +/- 0.85 (n = 23) and 2.20 +/- 0.86 units/mg (n = 65), respectively. Linear regression analysis comparing SAI values and serum protein levels showed no correlation (r = 0.21). These results suggest the decrease of the BIP is associated with malignant disease. Additional controlled studies are required before the significance of this association can be adequately assessed.

Adolescent↗
PubMed1981

Inhibition of bleomycin-induced DNA breakage by superoxide dismutase.

Inhibition of bleomycin (BLM)-induced DNA breakage by superoxide dismutase (SOD) has been reported and presumed to be due to its removal of the superoxide free radicals generated by BLM in the presence of iron(II). We have studied the possibility that the inhibitory effect might result from DNA-binding of SOD. The effect of copper-zinc SOD on BLM-induced DNA degradation was investigated using the PM-2 DNA fluorescence technique. PM-2 DNA was incubated with BLM in the presence or absence of native and heat-inactivated copper-zinc SOD as determined by the epinephrine autoxidation method. The concentrations of SOD required to inhibit 50% PM-2 DNA degradation for the native and the inactivated SOD were 100 and 120 microgram/ml, respectively. Analysis of the reaction mixture by agarose gel electrophoresis confirmed the absence of DNA degradation by BLM in the presence of either form of SOD. PM-2 DNA was shown to bind native or inactivated SOD by Sephadex G-100 column chromatography, fluorescence-quenching studies, and agarose gel electrophoresis. Thus, these results indicate that SOD is able to bind to PM-2 DNA and inhibit BLM-induced degradation independently of its free radical-scavenging activity. The inhibitor was more effective against BLM than other compounds which degrade PM-2 DNA. This suggests that SOD may bind to BLM-binding and/or BLM degradation sites in PM-2 DNA, and the observed inhibition is unrelated to its effects on free radicals.

Binding Sites↗
PubMed1979

Use of PM-2 DNA degradation as a pharmacokinetic assay for bleomycin.

The PM-2 DNA fluorescence assay has been shown to be a rapid, sensitive, and reproducible assay for bleomycin biochemical activity. The assay can detect bleomycin in human serum in the nmol range. The method measures DNA degradative activity of bleomycin and could be used to determine activity of bleomycin analogs and metabolites. The usefulness of the assay to perform bleomycin pharmacokinetic studies in cancer patients has been demonstrated. Linear regression analyses of parallel bleomycin assays with the radioimmunoassay gave a coefficient of correlation of 0.98 to 0.78 with trichloroacetic acid-treated serum. These results indicate excellent agreement between the two assays.

Adult↗
PubMed1976

Isolation and identification of two learning-induced brain peptides.

Goldfish were trained either to avoid the blue compartment of a tank and swim into the green compartment or, conversely, to avoid green and prefer blue. Preliminary experiments indicated that acquisition of the avoidance behavior was associated with the presence in the brain of two peptides, one found in blue avoiding (BA), another in green avoiding (GA) fish. With the help of behavioral bioassays, the peptides were isolated and purified, and their structure was determined by ultrasmicroanalytical techniques. The sequence of the BA peptide, pglu-ile-gly-ala-val-phe-pro-leu-lys-tyr-gly-ser-lys-OH was reproduced by synthesis. Sequential analysis of the GA peptide gave two alternative structures, NAc-lys-gly-gln-ile-ala-val-phe-pro-leu-lys-tyr-gly-ser-OH or NAc-lys-gly-ala-val-gln-ile-phe-pro-lys-tyr-gly-ser-OH, both of which are being synthetized to be compared with the natural compound. Overlapping sequences between the BA and GA peptides suggest the existence of a family of peptides associated with behavior based on color discrimination.

Amino Acid Sequence↗