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Biomedical subjects

M Salmona

Publications and source records attributed to M Salmona.

At least 145 records · Page 8Linked to original sources
PubMed1985

Tumor-derived chemotactic factor(s) from human ovarian carcinoma: evidence for a role in the regulation of macrophage content of neoplastic tissues.

Supernatants from freshly disaggregated human ovarian carcinomas maintained in vitro for 24 hr, from primary ovarian carcinoma cultures (4-6 days in culture) and from established ovarian cancer cell lines were examined for chemotactic activity on blood monocytes in blind-well chemotaxis chambers. Tumor-cell culture supernatants induced migration of peripheral blood monocytes across polycarbonate filters with considerable heterogeneity among different tumors. Induction of migration occurred only in the presence of a gradient between the lower and upper compartments of the chamber. Chemotactic activity was characterized by means of supernatants from primary ovarian carcinoma cultures. Chemotactic factor(s) was (were) produced in serum-free conditions and the production was inhibited by emetine but not by mitomycin C. The activity was destroyed by exposure to proteolytic enzymes and by heating at 100 degrees C but was unaffected by RNase, DNase, lipase and exposure to extreme pH values or heating at 56 degrees C. Upon fractionation on Sephadex G 75, the activity eluted as a single peak in the cytochrome C region, corresponding to an apparent molecular weight of about 12 kd. The percentage of macrophages was assessed in 25 freshly disaggregated tumor specimens. Ovarian carcinomas were heterogeneous in their macrophage content with values ranging from 4 to 36%. A significant (r = 0.62; p = 0.00097), though far from absolute, correlation was found between chemotactic activity of culture supernatants and percentage of tumor-associated macrophages. Tumor-derived chemotactic factor(s) could be one of the mechanisms involved in the regulation of the macrophage content of human ovarian carcinomas.

Carcinoma↗
PubMed1985

Platelet derived growth factor induces ornithine decarboxylase activity in NIH 3T3 cells.

Incubation with highly purified human Platelet Derived Growth Factor induced ornithine decarboxylase activity in quiescent NIH 3T3 cells concomitantly with mitogenic stimulation. Pretreatment of cells with a specific ornithine decarboxylase inhibitor, DL-alpha-difluoromethyl-ornithine significantly inhibited the effect of the mitogen on DNA synthesis. These experiments suggest that the mitogenic activity of Platelet Derived Growth Factor, similarly to that of other serum growth factors or tumor promoters, is mediated through rise in polyamine levels.

Animals↗
PubMed1985

Prostaglandins and aminoglycoside nephrotoxicity.

The role of prostaglandins in the development of aminoglycoside-induced acute renal failure was studied in CD-COBS rats (200 to 250 g). The animals were treated with gentamicin (80 mg/kg), acetylsalicylic acid (ASA, 100 or 200 mg/kg), or both drugs or saline for 5 or 10 days. Renal function was studied measuring creatinine clearance, blood urea nitrogen (BUN), and serum electrolytes, urine osmolality, and maximal urinary concentrating capacity after water deprivation and vasopressin administration. Gentamicin toxicity on the proximal tubule was evaluated by measuring urinary excretion of the lysosomal enzyme N-acetylglucosaminidase (NAG). Renal prostaglandin (PG) production was evaluated measuring the concentration of PGE2, PGD2, PGF2 alpha, 6-keto-PGF1 alpha, and thromboxane B2 (TXB2) in whole renal homogenate after a 15-min incubation at 37 degrees C using gas chromatography-mass spectrometry. Gentamicin alone reduced the glomerular filtration rate (GFR) 20 to 30% after 5 and 10 days of treatment. Combination with ASA potentiated the toxic effect of the aminoglycoside after 10 but not after 5 days of treatment. Similarly, gentamicin reduced the urinary concentrating capacity and addition of ASA worsened the effects. Gentamicin markedly increased NAG excretion but this effect was reduced by ASA, probably as a result of lysosomal stabilization. ASA alone inhibited the production of prostaglandins in renal tissue by 70 to 90% after single or multiple doses. The animals treated with gentamicin alone presented a significant, specific increase in PGE2 production after 10 days of treatment but this increase did not occur when the two compounds were given together. Since PGE2 has a vasodilatory effect in the kidney these results suggest that it may play a specific role in maintaining normal renal blood flow and GFR during the development of aminoglycoside nephrotoxicity. The inhibition of prostaglandin production by nonsteroid anti-inflammatory drugs prevents this compensatory mechanism and worsens the renal damage.

Analysis of Variance↗
PubMed1985

Kinetics of monosodium glutamate in human volunteers under different experimental conditions.

The kinetics of glutamic acid (GA) in plasma was studied in human volunteers after administration of monosodium glutamate (MSG) at different doses--43 mg/kg (3 g/70 kg) and 64 mg/kg (4.5 g/70 kg)--and in bouillon solutions of different concentrations (1.5-3.5%). MSG was administered to the subjects either during fasting or immediately after a standard meal. In the fasted subjects MSG administration caused a dose-dependent increase in plasma GA levels. In contrast, ingestion of MSG with a meal did not result in any significant increases in plasma GA levels in comparison with the wide variations observed in plasma GA after ingestion of a meal without added MSG.

Adult↗
PubMed1985

Perinatal development of cytochrome P-450, cytochrome C reductase, aryl hydrocarbon hydroxylase, styrene monooxygenase, and styrene epoxide hydrolase in rabbit liver microsomes and nuclei.

The development of cytochrome P-450, cytochrome C reductase, aryl hydrocarbon hydroxylase, styrene monooxygenase, and styrene epoxide hydrolase was studied in fresh rabbit liver nuclear and microsomal preparations. Enzymatic activities were determined in rabbit fetus at 21 and 30 days of gestation and in rabbits at 1, 5, 11, 22, 44, and 60 days of age. In extrauterine life, nuclear cytochrome P-450, aryl hydrocarbon hydroxylase, and styrene epoxide hydrolase were found to develop later than their microsomal counterparts, whereas nuclear cytochrome C reductase developed earlier than its microsomal counterpart. The behavior of styrene monooxygenase was more complex. The only activities detectable before birth were styrene epoxide hydrolase, styrene monooxygenase, and cytochrome C reductase in both nuclei and microsomes. The microsomes-to-nuclei epoxide hydrolase activity ratio was almost ten times the microsomes-to-nuclei styrene monooxygenase ratio, indicating a dissociation in the development of the two enzymes in rabbits. Nuclear metabolic activity was high at all ages, suggesting possible toxicological relevance.

Animals↗
PubMed1985

Correlation between newborn gastric aspirate microviscosity and gestational age.

Fluorescence polarization (FP) values were determined in 59 samples of amniotic fluid and in 56 samples of newborn gastric aspirate, collected from the 28th to 41st week of gestation. Both amniotic fluid and gastric aspirate FP values showed a significant correlation respectively with gestational age (r = 0.77; p less than 0.01 and r = 0.50; p less than 0.01). The two regression lines were parallel (F = 0.052; p = 0.8046). Mean FP of gastric aspirate were about 0.05 lower than those of amniotic fluid. One infant whose gastric aspirate FP value was 0.342 developed RDS.

Amniotic Fluid↗
PubMed1985

Role of reactive oxygen intermediates in the interferon-mediated depression of hepatic drug metabolism and protective effect of N-acetylcysteine in mice.

Interferon (IFN) and IFN inducers are known to depress hepatic microsomal cytochrome P-450 levels, and the liver toxicity of IFN was reported to be lethal in newborn mice. We have observed that administration to mice of IFN and IFN inducers caused a marked increase in liver xanthine oxidase activity. Because this enzyme is well known to produce reactive oxygen intermediates and cytochrome P-450 was reported to be sensitive to the oxidative damage, we have tested the hypothesis that a free radical mechanism could mediate the depression of cytochrome P-450 levels by IFN. Administration to mice of the IFN inducer polyinosinic-polycytidylic acid (2 mg/kg i.p.) caused a 29 to 52% decrease in liver cytochrome P-450. Concomitant p.o. administration of the free radical scavenger, N-acetylcysteine (as a 2.5% solution in drinking water), or the xanthine oxidase inhibitor, allopurinol (100 mg/kg), protected against the IFN-mediated depression of P-450 kg), protected against the IFN-mediated depression of P-450 levels. The results suggest that an increased endogenous generation of free radicals, possibly due to the induction of xanthine oxidase, is implicated in the IFN-mediated depression of liver drug metabolism. The relevance of these data also extends to cases in which this side effect is observed in pathological situations (e.g., viral diseases and administration of vaccines) associated with an induction of IFN.

Acetylcysteine↗
PubMed1984

Diazepam increases membrane fluidity of rat hippocampus synaptosomes.

Diazepam in vitro produced a concentration-dependent increase of membrane fluidity in crude synaptic membranes from rat hippocampus, but not cerebellum. Similar effects were obtained with higher concentrations of Ro 15-1788 and PK 11195, while zopiclone was completely inactive. In vivo acute treatment with diazepam and Ro 15-1788 gave results similar to those in vitro. The specific benzodiazepine antagonist also significantly increased membrane fluidity and was not able to reverse diazepam's effect. The data are discussed in terms of a possible role of protein kinase inhibition by the drugs not mediated by the 'central' or 'peripheral' type of benzodiazepine receptors.

Animals↗
PubMed1984

Characterization of arachidonic acid metabolic profiles in animal tissues by high-resolution gas chromatography-mass spectrometry.

A standardized, highly specific routine method was developed for the quantitative profiling of cyclooxygenase metabolites of arachidonic acid in animal tissues. Whole homogenates were used to assess the potential capacity of tissues to metabolize endogenous arachidonic acid. Samples were analyzed by high-resolution gas chromatography-mass spectrometry in the selected ion monitoring mode. The screening of several rat tissues by this method revealed marked tissue-specificity in both the synthesis capacity and prostaglandin profile. The major products detected were: 6-ketoprostaglandin F1alpha for lung, stomach, muscle and heart; prostaglandin D2 for spleen, brain and liver; prostaglandin F2alpha for kidney and prostaglandin E2 for seminal vesicles. Marked species differences were found when guinea pig tissues were analyzed.

Animals↗
PubMed1984

Enhanced xanthine oxidase activity in mice treated with interferon and interferon inducers.

Administration to mice of either interferon (IFN) or IFN inducers resulted in a marked increase of xanthine oxidase (XO) activity in different organs. Dose response studies revealed that serum XO was increased by administration of polyinosylic-polycyticylic acid (poly I-C) at doses as low as 0.1 mg/kg. In view of the well known ability of XO to generate superoxide radicals it is suggested that its induction might play a role in several biological effects of IFN.

Animals↗
PubMed1984

Kinetics of 3-tert-butyl-4-hydroxyanisole (BHA) in man.

High-resolution capillary gas chromatography-mass spectrometry with selective ion monitoring and using deuterated 3-tert-butyl-4-hydroxyanisole (BHA) as an internal standard was used to measure BHA in the plasma and urine of human volunteers after oral administration of 30 or 5 mg of the compound in olive oil. Pharmacokinetic studies showed similar plasma-concentration profiles in subjects treated with either level of BHA. About 20% of the administered dose was excreted as BHA glucuronide in the urine within the first 24 hr.

Administration, Oral↗
PubMed1984

Different susceptibility of mouse tissues to porphyrogenic effect of 2,3,7,8-tetrachlorodibenzo-p-dioxin.

The porphyrogenic effect of chronic administration of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) (25 micrograms/kg/week) to male C57BL/6 mice was evaluated through quantitative and qualitative analysis of the porphyrins accumulated and of porphyrinogen carboxylase activity in liver, kidney, spleen, brain and erythrocytes. The liver was the principal site of action, both for porphyrin accumulation and for enzyme inhibition, with kidney next, whereas brain and erythrocytes were unaffected. In the spleen, despite unchanged formation of total products of uroporphyrinogen III decarboxylation, both an increase and a decrease of coproporphyrinogen formation were observed, the decrease being concomitant with a higher accumulation of tissue porphyrins. When a response to TCDD was found, the formation of the products of decarboxylaction of uroporphyrinogen III were affected to different extents. The pattern of enzyme inhibition paralleled data reported in the literature regarding tissue distribution of TCDD and indicated that TCDD porphyria is a suitable experimental model for the human 'sporadic' type of porphyria cutanea tarda (PCT).

Animals↗
PubMed1984

Prostaglandin endoperoxide synthetase and the activation of benzo(a)pyrene to reactive metabolites in vivo in guinea pigs.

The role of prostaglandin endoperoxide synthetase in the in vivo activation of benzo(a)pyrene to reactive metabolites capable of interacting irreversibly with cellular macromolecules was studied in guinea pig liver, lung, kidney, spleen, small intestine, colon, and brain. DNA and protein covalent binding experiments were made after systemic administration of acetylsalicylic acid (200 mg/kg) followed by radiolabeled benzo(a)pyrene (4 microgram/kg). Results are compared with a control situation in which the prostaglandin endoperoxide synthetase inhibitor (acetylsalicylic acid) was not administered. No decrease in the level of DNA or protein benzo(a)pyrene-derived covalent binding was observed in any of the tissues studied.

Animals↗
PubMed1983

Styrene oxidation to styrene oxide in human erythrocytes is catalyzed by oxyhemoglobin.

Oxygenated human erythrocytes catalyzed the oxidation of styrene to styrene oxide. This reaction was inhibited by CO but not by superoxide dismutase, catalase and scavengers of hydroxyl radicals. In partially deoxygenated erythrocytes styrene oxidation showed a linear relationship with the molar fraction of oxyhemoglobin. These data indicate that oxyhemoglobin and not free oxygen radicals are involved in styrene oxidation.

Carbon Monoxide↗
PubMed1983

N-acetyl-beta-D-glucosaminidase (NAG) and NAG isoenzymes in children with upper and lower urinary tract infections.

The use of N-acetyl-beta-D-glucosaminidase (NAG) to diagnose the site of urinary tract infection was studied in pediatric patients. Differentiation between upper and lower tract infections (UTI) was based on clinical grounds and on elevated erythrocyte sedimentation rate, C-reactive protein and fever. NAG excretion expressed as nmol X h-1 X mg-1 of urinary creatinine was higher in children with upper UTI (mean +/- SE 906 +/- 236) than in those with lower UTI (145 +/- 23) or healthy children (151.6 +/- 10) (p less than 0.01 by Duncan's test). In children with upper UTI, NAG excretion fell in parallel with the remission due to antibiotic treatment. This however was not seen in children treated with aminoglycosides. A specific and significant elevation (p less than 0.01) of the B isoenzyme of NAG was documented in children with upper UTI but not in those with lower UTI (B form in upper UTI 49.2% +/- 3.9 versus 21.9 +/- 3.3 in lower UTI; healthy children 18.9 +/- 3.4). The percentage of B isoenzyme excreted was high in two children with upper UTI but was low total NAG urinary excretion, suggesting that the quantification of isoenzymes offers further specificity in diagnosis. We conclude that the measurement of NAG and its isoenzymes in children with UTI provides useful information in the diagnosis of the site of infection.

Acetylglucosaminidase↗
PubMed1983

Regulation of the macrophage content of neoplasms by chemoattractants.

Factor chemotactic for mononuclear phagocytes was found in supernatant fluids of cultured human and mouse tumor cells. In 11 mouse tumors there was a correlation observed between chemotactic activity and macrophage content of neoplastic tissues. Tumor-derived chemoattractants appear to participate in the regulation of tumor-associated macrophages.

Animals↗
PubMed1983

Perinatal development of styrene monooxygenase and epoxide hydrolase in rat liver microsomes and nuclei.

Nuclear enzymes were found to develop earlier than the corresponding microsomal activities. In fact styrene monooxygenase enzymatic activity at 18 days gestational age reached about half the values of adult animals, whereas fetal microsomal activity was only about 1/20 the adult level at the same age. In microsomes and nuclei the ontogenic development of epoxide hydrolase is slightly slower than styrene monooxygenase. This suggests that fetuses and newborn animals are exposed to higher risk of accumulation of styrene-7,8-oxide, a toxic and possibly teratogenic product of styrene monooxygenase.

Age Factors↗