Search PubMed⌕ Search

Biomedical subjects

P Gil

Publications and source records attributed to P Gil.

At least 55 records · Page 3Linked to original sources
PubMed1988

Effect of hyperoxia acclimation on catalase and glutathione peroxidase activities and in vivo peroxidation products in various tissues of the frog Rana ridibunda perezi.

Among vertebrates, adult amphibians are known to be especially tolerant to exposure to high environmental oxygen tensions. To clarify the basis for this high O2 tolerance, adult Rana ridibunda perezi frogs were acclimated for 15 days to water-air phases with either 149 mm Hg O2 (normoxia) or 710 mm Hg O2 (hyperoxia). At the end of the acclimation, various morphometric and biochemical parameters related to oxidative stress were measured in seven organs and tissues. Hyperoxia acclimation did not change either the total weight of the animals or the total and relative wet weights of the organs studied, except for the brain, which showed weight increases in the hyperoxic group. In vivo tissue peroxidation increased in the kidney; decreased in the skeletal muscle and skin; and did not change in the liver, lung, brain, and heart after hyperoxic exposures. Whereas liver, lung, and skin showed glutathione peroxidase (GSH-Px) activities with both cumene hydroperoxide (cumene-OOH) and H2O2 as substrates, skeletal muscle only showed H2O2 GSH-Px activity. Hyperoxia acclimation did not change either catalase (CAT) or GSH-Px activities in any organ, except for the liver in which CAT activity was induced by hyperoxia. Thus hyperoxia tolerance in this species does not need the induction of H2O2-detoxifying enzymes in the majority of the organs. It is suggested that the high O2 tolerance of this amphibian species is related to its comparatively high constitutive GSH-Px activities.

Adaptation, Physiological↗
PubMed1988

Physiological significance of catalase and glutathione peroxidases, and in vivo peroxidation, in selected tissues of the toad Discoglossus pictus (Amphibia) during acclimation to normobaric hyperoxia.

1. Various parameters related to oxidative stress were measured in adult Discoglossus pictus acclimated for 15 days to either normoxia or hyperoxia (PO2 = 710 mmHg). 2. Total weight of the toads and total and relative wet weight of liver, kidneys, lungs and heart were not changed by hyperoxic acclimation. 3. In vivo tissue peroxidation increased in lung, decreased in skeletal muscle, and was not changed in liver, kidney, heart and skin after hyperoxic exposure. 4. Hyperoxic acclimation increased catalase activities in the lung, liver, kidney and heart but not in skeletal muscle and skin. 5. Liver showed higher GSH-peroxidase activity with cumene-OOH than with H2O2 as substrate, whereas lung, skeletal muscle and skin presented similar GSH-peroxidase activities with both substrates. 6. GSH-peroxidase activities did not change between hyperoxic and normoxic animals in liver, lung, skeletal muscle and skin. 7. These results show that catalase, not GSH-peroxidase, is the principal H2O2 detoxifying enzyme involved in the adaptation of D. pictus to hyperoxia.

Adaptation, Physiological↗
PubMed1987

Different levels of hyperoxia reversibly induce catalase activity in amphibian tadpoles.

Studies about the proposed antioxidant physiological role of the catalase (CAT) enzyme in relation to different environmental oxygen tensions are reported for the first time in amphibian larvae of Discoglossus pictus and Rana ridibunda perezi during their development. The CAT levels of whole tadpoles increased constantly in both species during the larval period, reaching a maximum during the metamorphic climax. All through development, CAT activity levels were always greater in D. pictus than in R. ridibunda perezi. This correlates well with the already reported higher SOD activity and hyperoxia resistance of the D. pictus species when compared to R. ridibunda perezi. Long-term acclimation to different levels of hyperoxia (40, 60, and 100% O2) showed dose-related increases in the CAT activity of D. pictus tadpoles. These increases did not take place when the animals were subjected to acute hyperoxia (24 h). The increase in CAT activity observed after 15 days of acclimation to acute hyperoxia (710 mm Hg: 100% O2) was reversed after 15 additional days of postacclimation to normal air (149 mm Hg O2). When recently metamorphosed frogs were acclimated to acute hyperoxia, significant increases in CAT activity were observed after 15 days, but not after 7 days. The results are interpreted as supporting a protective role for the CAT enzyme in amphibian larvae and froglets against oxygen toxicity.

Aging↗
PubMed1985

Catalase enzymatic activity and electrophoretic patterns in adult amphibians--a comparative study.

Catalase electrophoretic patterns and enzymatic activities were measured in four organs of two anuran species, Rana ridibunda perezii and Discoglossus pictus. The D. pictus enzyme appeared as two distinguishable bands, whereas R. ridibunda catalase was monomorphic. Electrophoretic mobility of the major D. pictus catalase band was greater than that of R. ridibunda. Enzymes from both species showed slower mobility than that from bovine liver. Catalase activities did not show significant differences according to sex in any of the organs tested in R. ridibunda. Enzyme activities were similar in liver, kidney and brain when both species were compared. Only the heart showed much higher activity in D. pictus than in R. ridibunda. The catalase activity levels followed the order: liver greater than kidney greater than heart in both species. The heart showed higher activity than the brain in D. pictus but not in R. ridibunda.

Animals↗
PubMed1983

Time dependency of adriamycin and adriamycinol kinetics.

Adriamycin was administered by IV injection to seven patients with various solid tumors at a dose of 30 mg/m2 during successive courses. Extraction was carried out by the SEP-PAK method for plasma and by solvents for urine. Plasma and urinary levels of adriamycin and adriamycinol were determined by high-performance liquid chromatography over 72-h period after injection. Pharmacokinetic parameters for adriamycin and adriamycinol were calculated for each course of treatment. The results show significant inter- and intra-individual variations in the kinetics and elimination of both compounds. The analysis of pharmacokinetic data reveals a wide variability in the fluctuations observed during the successive courses in different patients. This study confirms the time-dependency of ADR kinetics.

Adult↗
PubMed1983

Quantitation of adriamycin in plasma and urine: comparative study of radioimmunoassay and high-performance liquid chromatography methods.

The response of tumours to adriamycin, and the cardiotoxicity of the drug, may be related to its pharmacokinetics and plasma levels. Rapid and sensitive methods of adriamycin determination in plasma and urine samples are thus needed. A comparative study shows that high-performance liquid chromatography with fluorimetric detection is a reliable and specific method, but it is relatively slow and sometimes lacks sensitivity. A commercially-available radioimmunoassay kit is convenient, but there is a cross reaction with the major metabolise adriamycinol and unless the assay is combined with an extraction step, it gives erroneously high results.

Journal Article↗
PubMed1981

Clearance of sensitized erythrocytes in NZB/NZW mice. Effects of castration and sex hormone treatment.

The clearance of particulate immune complexes consisting of erythrocytes sensitized with IgG or complement was investigated in (NZB x NZW)F1 (B/W) mice. Treatment of castrated B/W mice with androgen or estrogen was able to modulate this clearance. Young (3-month-old) male and female B/W mice cleared IgG-sensitized mouse erythrocytes rapidly, whereas older males (13 months) and females (7 months) showed a marked impairment in their ability to clear these cells. In addition, erythrocytes sensitized with complement in the absence of antibody were cleared within 5 min in young B/W mice. Older mice showed a greater and more rapid clearance rate of these cells. Castrated female B/W mice treated with androgen implants from three weeks of age showed improved clearance of IgG-sensitized erythrocytes at 7 months, whereas estrogen-treated male mice showed delayed clearance. These results suggest an age-dependent defect in the clearance of IgG-sensitized particles, perhaps due to diminished levels of serum complement and/or saturation of Fc receptors. In addition, there is an alteration in the clearance of complement-sensitized erythrocytes which may be related to changes in macrophage activity or enzyme inactivators of C3 and C4. The possible mechanisms responsible for the hormonal modulation of clearance are discussed in relation to the known ability of these hormones to influence autoimmune diseases.

Androgens↗
PubMed1979

Feminizing adrenocortical carcinoma in a postmenopausal woman.

The successful surgical removal of a feminizing adrenal tumour in a postmenopausal woman is described. Most of these tumours are malignant and the pathological findings and the biological behaviour of the tumour frequently do not correlate, so that a careful follow-up is necessary. In the presence of vaginal bleeding in a postmenopausal woman endometrial carcinoma should be considered. If this has been ruled out and if oestrogens are elevated with low plasma gonadotrophins, a feminizing ovarian or adrenal tumour should be considered.

Adrenal Cortex Neoplasms↗
PubMed1977

Adrenal cysts: diagnostic value of "intravenous viscerogram".

Two cases of adrenal pseudocysts are presented, one secondary to the necrosis of an adenoma and the other a hemorrhagic pseudocyst. The diagnosis of these tumors is usually made radiologically owing to the vagueness of symptoms and nonexistent specific laboratory examinations, so that preoperative diagnosis is uncommon. We present a radiologic technique, intravenous viscerogram, which may be useful in the diagnosis of adrenal cysts. This procedure is easy to carry out and has almost no complications for the patient. The classification, clinical findings, and surgical treatment of adrenal cysts are discussed.

Adrenal Gland Diseases↗
PubMedDate not supplied

[Antioxidant enzymes in acute cerebral infarction].

BACKGROUND AND PURPOSE: Oxidative modification of DNA, protein and lipids by reactive oxygen peroxides plays an important role in acute cerebral infarction. The biological antioxidant defence system against oxidative stress is an integrated array of enzymes such as superoxide dismutase (SOD), catalase (CAT) and glutathion peroxidase (GPx). The purpose of this work was: 1. To investigate the evolution of SOD and CAT activities as possible markers of oxidative activity in patients with acute cerebral infarction. 2. To establish the relationship between the type of stroke and the activity of these two enzymes. 3. To analyze the relationship between the degree of neurological deficits of patients with stroke and SOD and CAT activities. PATIENTS AND METHODS: This is a prospective study comprising 45 patients with acute cerebral infarction (24 females and 21 males), aged from 48 to 96. The infarcts were classified in atherotrombotics and cardioembolics. SOD and CAT activities were measured on days 1, 3, 6 and 15. RESULTS: Activities of SOD and CAT in patients on admission were lower than those of controls and showed a gradual increase over time. The activity mean of SOD was significantly higher in cardioembolic infarctions than in atherotrombotic infarctions (p < 0.05). SOD activity was significantly lower for Mathew score > 60, while CAT activity was higher. CONCLUSIONS: Our findings suggest that there is a progressive increase in SOD and CAT activity during ictus evolution, a different activity of SOD and CAT in cardioembolic and atherotrombotic infarctions, and that there is a relationship between activity of antioxidant enzymes and Mathew's score.

Acute Disease↗