Biomedical subjects
Publications and source records attributed to C L Galli.
This study attempts to elucidate, in man and rabbit neutrophils, the relevance of extracellular Ca2+ and Mg2+ to actin polymerization induced by fMLP, a chemotactic peptide. The presence of as little as 0.2 mM divalent ions in the cell suspending medium inhibits the actin polymerization in rabbit neutrophils, and partially reduces it in human neutrophils.
The hypothesis that incorporation of tryptophan (TRY) into proteins is the mechanism underlying the decrease in plasma and tissue TRY levels after a TRY-free amino acid mixture was investigated. Rats fasted 15 hours were pretreated with saline or with the protein synthesis inhibitor cycloheximide (CHEX) and treated with saline or a TRY-free amino acid mixture. In a first experiment, in saline pretreated rats the TRY-free mixture caused a decrease of 49% in total plasma TRY, of 64% in free plasma TRY, of 66% in brain TRY and of 42% in liver TRY. After 5 mg/kg of CHEX the same TRY-free diet caused a decrease of 5% in total plasma TRY, 14% in free plasma TRY, 18% in brain TRY and 9% in liver TRY. In a second experiment, the TRY-free diet caused a 43% decrease of total plasma TRY in saline pretreated animals and a decrease of 15%, 6% and 2% respectively after the pretreatment with 0.3, 1.0 and 5.0 mg/kg of CHEX. In brain TRY, the TRY-free diet caused a 62% decrease in saline pretreated rats and a decrease of 38%, 20% and 19% respectively after the pretreatment with 0.3, 1.0 and 5.0 mg/kg of CHEX. Since 5.0 mg/kg of CHEX almost completely block protein synthesis and since doses of CHEX from 0.3 to 5.0 mg/kg cause a dose-dependent inhibition of protein synthesis, our data support the hypothesis that protein synthesis is the mechanism through which TRY-free mixtures decrease TRY levels.
A case of triphenyltin acetate (TPTA) poisoning is described. The patient, who had been exposed mainly to cutaneous absorption, showed acute stages of an urticarial eruption, signs of hepatic injury, slight glucose intolerance, and electroencephalographic abnormalities. Concomitant with the highest concentrations of tin in plasma and the peak of tin excretion in urine, neutrophils did not show the normal increase in actin polymerisation after stimulation with a chemotactic peptide (100 nM fMLP). The peak of urinary excretion of tin occurred between the fifth and the sixth day after poisoning; subsequently, the rate of excretion became slow, suggesting biphasic kinetics with the possibility of a cumulative trend.
Formaldehyde (FA) has been commercially produced since the early 1900s. Its widespread use in a variety of applications is known to result in appreciable exposure of workers and of a section of the general population. Formaldehyde is a normal metabolite in mammalian systems. It occurs in air as a product of the natural photooxidation of automobile exhaust, combustion processes, incinerators; formaldehyde has been found in municipal and industrial effluents and is present in food either naturally (fruits and vegetables, in the order of parts per million), or as a result of its use as a food additive. The use of FA and its derivative, hexamethylenetetramine (HMT), which gradually decomposes to FA under acidic conditions as antimicrobial agents in food, raises questions about their potential chronic oral toxicity. Furthermore, since FA is a very reactive compound and reacts with different macromolecules such as proteins and nucleic acids, the safety evaluation of FA as a cheese additive must take into account the toxicity of the reaction products between FA and milk components. Biochemical aspects, acute and short-term toxicity studies including mutagenicity, multigeneration, and reproduction studies, long-term carcinogenicity studies after oral administration of FA and HMT are reviewed in this paper. The results of these studies indicate that repeated oral exposure of a relatively large amount of FA that could overwhelm the normal metabolic capacity of animals to convert FA into formiate, CO2, and water produces histopathological gastric changes. This paper correlates the hazard caused by the exposure to low levels of FA, as far as its carcinogenic potential by oral route is concerned per se or regarding its use as a food additive. Based on the evidence that FA is formed naturally in food and is a normal mammalian metabolite and that a threshold for carcinogenicity exists both after exposure by inhalation and oral administration, it may be deduced that FA is not carcinogenic at low levels of exposure.
12-O-tetradecanoylphorbol-13-acetate (TPA) caused a rapid activation of protein kinase C in a murine (HEL-30) and in a human (NCTC) epidermal cell line. In HEL-30 cells, protein kinase C activation is followed by ornithine decarboxylase stimulation and cell proliferation, events inhibited by H-7, a specific inhibitor of protein kinase C. TPA in NCTC cells inhibited the basal ornithine decarboxylase activity and cell growth, whereas H-7 did not modify TPA effect. The response of NCTC cells was not due to direct toxicity of TPA. These data confirm that in murine epidermal cells, the proliferation induced by TPA is mediated by protein kinase C, whereas in a human skin-derived cell line these events are not or inversely associated.
A subacute toxicity study of Indomethacin administered by oral route, was carried out in the marmoset (Callithrix jacchus). Groups of three males and three females received Indomethacin directly into the stomach by means of a catheter for a period of 4 weeks at the dose levels of 0, 2, 6, and 12 mg/kg body wt/day and then were euthanized for pathological evaluation. All marmosets given 12 mg/kg/day and one marmoset given 6 mg/kg/day died during the dosing period (within 20 days). At 12 mg/kg/day, Indomethacin induced severe gastrointestinal toxicity (hemorrhage, ulcers, and necrosis with peritonitis), while at the dosages of 6 and 2 mg/kg/day some moderate to slight dose-related functional and morphological renal alterations (increase of serum urea, reduction of serum albumin, increase of serum potassium and/or chloride, and subacute inflammation) were observed. The fact that in many respects these alterations are similar to those observed in man is a further demonstration of the validity of the marmoset as an experimental model.
The effect of tributyltin chloride (TBT) on ATP levels and protein synthesis was investigated in a murine epidermal cell line (HEL-30). Five minutes after exposure to 10(-5) M TBT, cellular levels of ATP decreased by 57% and protein synthesis was significantly inhibited. The effect of ATP was stable up to 2 h incubation, whereas inhibition of protein synthesis increased with time of treatment. Partial (1 h) or complete (2 h) recovery of the two cell functions was observed when dithiothreitol (DTT) was added to the medium, 5 min after the damage and in the absence of TBT. The sequence of the observed effects suggests that TBT inhibition of protein synthesis is due to impairment of ATP production.
Albumin, at concentration normally present in plasma (approximately 600 microM), significantly inhibited leukotriene B4 formation induced by a receptor mediated (fMet-Leu-Phe) and a receptor independent (calcium ionophore A23187) stimuli in human neutrophils. The inhibition of leukotriene B4 synthesis was accompanied by a concomitant reduction of neutrophil aggregation. In addition, this plasma protein prevented the increase in F-actin content of neutrophils stimulated with fMet-Leu-Phe and A23187, thus suppressing actin polymerization. These data indicate that albumin profoundly affects biochemical and functional aspects of neutrophils suggesting, for this plasma protein, a regulatory role in the overall pattern of the inflammatory reaction.
Arachidonic acid metabolism was evaluated in isolated rat hepatocytes after CCl4 exposure. CCl4 induced dose-dependently the synthesis and release of prostacyclin (PGI2) and thromboxane (TXB2). Treatment with prostaglandin E2 (PGE2) 30 min after exposure to CCl4, significantly reduced the cell damage as well as the release of TXB2 from the cells.
Spinacine (4,5,6,7-tetrahydro-1H-imidazo[4,5-c]pyridine-6-carboxylic acid), the major reaction product of formaldehyde added to Grana Padano cheese, was administered to five groups of ten rats of each set at dietary concentrations that provided doses of O (control), 15, 30, 60 or 300 mg/kg body weight/day for 13 wk. There were no adverse effects upon survival, growth or food intake. No significant treatment-associated changes were found in haematological parameters, in serum chemistry or organ weights at the end of the study. At autopsy, neither gross nor histological modifications were attributable to treatment with spinacine. In this study the no-effect dose level for spinacine was considered to be 300 mg/kg body weight/day.
The established mouse epidermis-derived cell line HEL/30 was incubated in the presence of 3H arachidonic acid (AA) for 1 h. After medium removal, cells were reincubated with fresh medium in the presence or absence of the calcium ionophore A23187 and tumor promoter 12-O-tetradecanoyl-phorbol-13-acetate (TPA). The AA metabolites formed were extracted from cell-free medium and analyzed using TLC and HPLC. The distribution of the recovered radioactivity showed PGE2, 15-hydroxy-eicosatetraenoic acid (15-HETE), and leukotriene B4 (LTB4), as major products of AA metabolism. The presence of calcium ionophore A23187 increased the release of radioactivity, without affecting the profile of metabolites present in the medium. TPA elicited a preferential increase of cycloxygenase metabolism, this effect being reversed by indomethacin. 5,8,11,14-eicosatetraynoic acid (ETYA) almost completely inhibited LT and HETE formation in A23187 and TPA-treated cells. The results show that HEL/30 cells are able to metabolize AA via both cyclo- and lipoxygenase pathways and that these activities can be modified by chemical means. This cell line might be a suitable tool for studying the involvement of arachidonic acid cascade in cell response to exogenous stimuli.
14C-Carmoisine (250/ug; 1.25 x 10(6) dpm) was incubated under strictly anaerobic conditions with resting cell suspension from stool specimens collected from male rats and human male healthy adults. The kinetics of azoreduction was determined as amount of naphthionic acid (NA), the stable metabolite of Carmoisine produced by the activity of the anaerobic bacteria. The analytical determinations were performed by radio-HPLC technique. There were no significant qualitative differences in the radiochromatographic profiles of samples obtained from human and rat flora suspensions. The calculated reduction rates were 5.03 +/- 0.18 nmoles of NA/250/ug protein/min, and 1.72 +/- 0.12 nmoles of NA/250/ug protein/min for rat and human faecal resting cells respectively. From our results it seems that the enzymatic reaction, following zero order kinetics, is similar for the two species and only the reduction rate is different.
Formaldehyde is added to milk in the production of grana cheese as an antimicrobial agent. In order to study the fate of the formaldehyde, a grana cheese preparation was made using 14C-labelled formaldehyde. The 14C-activity in the cheese was found to be mainly associated with the caseins, but it was not uniformly distributed among the different fractions (alpha s, beta- and gamma-caseins). gamma-Casein, separated by electrophoresis, was the most reactive component showing the highest specific activity. In the gamma-casein fractions, 99% of 14C-activity was associated with the basic amino acids. The only radioactive reaction product present in the gamma-casein fraction was identified by HPTLC and by an amino acid analyser to be spinacine, a condensation product of formaldehyde and histidine. Using the same method, other unknown radioactive products, of much less relevance, were detected in the total casein hydrolysate.
The development of met-enkephalin (ME) and substance P (SP) neurons has been studied in rats exposed to morphine during the perinatal period up to day 30 of life. Both peptides levels were measured by specific radioimmunoassays. ME developmental pattern is markedly affected by morphine in the pons-medulla oblongata, while SP does not seem to be influenced. It is suggested that the well known inhibitory effects of opiates on brain growth and maturation might take place by altering the developmental pattern of the endogenous opioid system.
Five fractions of an aqueous extract obtained from the roots of Echinacea angustifolia were separated on the basis of molecular weight. The topical anti-inflammatory activity of the fractions has been evaluated in mice using the Croton oil ear test. The fraction with a molecular weight between 30,000 and 100,000 was the most active in inhibiting the oedema; it also reduced the infiltration of inflammatory cells. The activity of this fraction was comparable with that of a raw polysaccharidic extract obtained from E. angustifolia roots by differential solubility. The high-molecular weight polysaccharides are therefore proposed as the anti-inflammatory principles of the plant.
In two groups of patients on chronic haemodialysis treatment, the common PVC-DEHP blood tubing was replaced with tubing containing tri-(2-ethylhexyl)-trimellate (TOTM) as plasticizer. The aim of the present study was to measure the amount of TOTM and/or its metabolites (TAE s) in plasma, resulting from TOTM that might leach from the dialysis tubes. The arterial levels of TAE s at the start of the dialysis sessions were monitored by Selected Ion Monitoring (SIM) analysis once a week for a period of 42 days. A gradual decrease in TAE was observed during the first 21 days of the haemodialysis treatment with the PVC-TOTM tubes. After three weeks, the TAE levels remained constant until the end of the study. On day 120 of the haemodialysis treatment, the plasma TAE concentrations from the inflow and outflow tubes of the dialyzer were monitored during a single haemodialysis session at different times after starting dialysis. At the beginning of the dialysis session, the mean concentration of TAE was 55.81 +/- 14.98 ng/ml (mean +/- standard error), while at the end the levels were 73.34 +/- 17.05 ng/ml. There were no significant differences between venous and arterial sampling points in the trimellitic ester concentrations. Less TOTM is apparently leached from haemodialysis than DEHP. TOTM can be recommended as an alternative plasticizer to DEHP, but its possible toxicity in humans should be investigated before it can be used routinely.
The fate of the plasticiser di-(2-ethylhexyl)-phthalate and/or its metabolites, phthalic acid esters (PAE), in 12 patients on chronic haemodialysis was studied. The total amount of PAE retained by the patients was estimated by monitoring the plasma concentrations from the inflow and outflow tubes of the dialyzer during 4-h dialysis sessions. There was an estimated uptake of 46 mg of PAE during a single dialysis session. The values for a volumetric factor (Vf) related to the increment in plasma PAE concentrations were found to increase during the first hour of treatment (72 litres at steady-state), and then to progressively decrease. The changes in the kinetic parameters during the dialysis session were grouped into three phases according to the fate of the plasticiser in the patient. We also monitored the plasma concentrations of PAE in the same patients for 40 days during dialysis with another kind of plasticised (tri-(2-ethylhexyl)-trimellitate [TOTM]) tubes. The PAE concentrations were similar to those found in healthy humans after about 5 weeks.
The anti-inflammatory activity of a polysaccharidic fraction (EPF) obtained from Echinacea angustifolia roots has been examined using the carrageenan paw oedema and the croton oil ear test. EPF (0.5 mg kg-1 i.v.) almost inhibited the carrageenan-induced oedema over 8 h and furthermore, EPF, topically applied, inhibited mouse ear oedema induced by croton oil. EPF also reduced the leukocytic infiltration of the croton oil dermatitis, evaluated both as peroxidase activity and histologically. After topical application EPF appears to be slightly inferior in potency to indomethacin. The results suggest that the anti-inflammatory activity of E. angustifolia resides in its polysaccharidic content.