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Biomedical subjects

C Rota

Publications and source records attributed to C Rota.

26 records · Page 2Linked to original sources
PubMed1997

ET-1 plasma levels during cold stress test in sclerodermic patients.

Endothelial cell injury in blood vessels of small arteries and capillaries is considered the primary event in the pathogenesis of systemic sclerosis (SSc). Because endothelin-1 (ET-1) is mainly released in the site of endothelial cell damage, thereby inducing a potent vasoconstriction, it was our intention to study ET-1 release in a group of SSc patients during a cold pressor test (CPT). Twelve SSc patients and a control group of 10 healthy subjects underwent CPT. Blood samples for ET-1 assay were collected at 90 and 180 seconds of exposure to cold stress. Heart rate and blood pressure were recorded at the same intervals. A capillaroscopic examination was performed in both groups before and after CPT. We observed significantly higher levels of plasma ET-1 in SSc patients compared with those of the control group at baseline (P=0.007) and at 90 (P=0.006) and 180 seconds (P=0.03) of CPT. During the test, the capillaroscopic examination showed a dramatic worsening of the vascular picture that was parallel to the increase in ET-1 plasma levels. This suggests that higher ET-1 plasma levels can have a part in the acute vascular reactivity of SSc patients undergoing CPT.

Aged↗
PubMed1997

[Presence of Listeria monocytogenes and Listeria sp. in fresh and cured sausages. Use of different conditions of time and temperature for incubation].

Two different temperatures for enrichment of Listeria monocytogenes and related species have been studied (1) cold enrichment at 4 degrees C (2) enrichment at 30 degrees C (FDA method). Also, two selective media for isolation were tested: Acriflavine-Ceftazidime agar (A.C.) and Palcam agar. We have studied 72 samples of dry-cured sausage (called 'longaniza') at different stages of maturation: fresh, semi-cured and cured samples. The most efficient method was cold enrichment at 4 degrees C during 5 days followed by isolation in Palcam agar, but results were only significant for fresh sausages (P < 0.05).

Animals↗
PubMed1996

The respiratory-chain poison antimycin A promotes the formation of DNA single-strand breaks and reduces toxicity in U937 cells exposed to t-butylhydroperoxide.

Antimycin A at levels that abolish oxygen consumption had a slight, although statistically significant, inhibitory effect on the toxicity elicited by t-butylhydroperoxide in U937 cells. The protective effect was observed after 6 h of post-treatment incubation, but was no longer apparent after 24 h. Unexpectedly, these events were associated with a marked accumulation of DNA single-strand breaks produced by low levels of t-butylhydroperoxide. Both an oxygen- and a carbon-centred radical were found to arise during treatment with t-butylhydroperoxide, and their formation was significantly lowered by antimycin A. Thus inhibition of electron transport at the level of complex III appears (a) to decrease the formation of toxic species which mediate, at least partially, the lethal effects elicited by t-butylhydroperoxide, and (b) to enhance the formation of DNA-damaging species generated at low concentrations of t-butylhydroperoxide. Rotenone and cyanide, which respectively inhibit complexes I and IV, did not affect DNA damage elicited by t-butylhydroperoxide. These results suggest that DNA single-strand breaks do not mediate the toxicity of t-butylhydroperoxide, and that specific mitochondrial functions might modulate the formation of the toxic and of DNA-damaging species generated by organic hydroperoxides.

Antimycin A↗
PubMed1990

A rise in haemoglobin levels may enhance serum triiodothyronine (T3). Concentrations in prepubertal patients with beta-thalassaemia major.

The aim of the present study was to investigate the effects of increased haemoglobin (Hb) levels on the thyroid function in patients with beta-thalassaemia major. Basal levels of thyroid hormones (T4, T3) and free thyroid hormones (fT4, fT3), basal TSH concentrations and the TSH responses to a TRH bolus (0.2 mg iv) were studied in ten euthyroid thalassaemic patients, aged 8 to 19 years, and in one 12 years-old thalassaemic girl with primary hypothyroidism. Five euthyroid thalassaemic patients (aged 8 to 12 years), as well as the hypothyroid thalassaemic girl, were prepubertal, whereas five euthyroid thalassaemic patients (aged 15 to 19 years) had delayed puberty. In each patient, the endocrine evaluation was carried out under conditions of low Hb levels (31 days after the last blood transfusion, mean Hb = 9.8 +/- 1.5 g/dl), and 11 days after the transfusion of 2 units packed red blood cells (PRBC). The latter increased significantly Hb concentrations in all the thalassaemic patients (mean Hb = 12.8 +/- 2.5 g/dl, P less than 0.001). Twelve normal prepubertal subjects, aged 6 to 11 years, served as the control group. Before the PRBC transfusion, basal T4, T3, fT4, fT3 and TSH concentrations were similar in euthyroid prepubertal thalassaemic patients (EPT) and in euthyroid patients with delayed puberty (EDPT), and were comparable to those in control subjects. The TSH responses to TRH (TSH peak, area and delta area) observed in EPT patients were similar to those in the EDPT group, but significantly higher in comparison with the normal children.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1988

Effect of increased haemoglobin levels on growth hormone (GH) secretion in beta-thalassaemia major: differences between prepubertal subjects and patients with delayed puberty.

Basal and L-dopa-stimulated secretion of growth hormone (GH) was investigated in 10 patients with beta-thalassaemia major. Five patients were prepubertal (chronological age 8 to 12 years), whereas 5 patients had delayed puberty (chronological age 15 to 19 years). Ten normal prepubertal subjects (chronological age 8 to 11 years) served as the control group. Each thalassaemic patient was subjected to two L-dopa tests (0.5 g L-dopa plus 0.7 mg/Kg body weight propranolol, orally): one was performed under conditions of low haemoglobin (Hb) levels (30 days after the last blood transfusion), and the second in the presence of increased Hb concentrations (10 days after the transfusion of packed red blood cells). Before the transfusion of packed red blood cells, basal GH concentrations were significantly higher in the patients with delayed puberty (4.3 +/- 1.6 ng/ml), than in prepubertal thalassaemic (1.8 +/- 0.9 ng/ml, p less than 0.05) and control (1.9 +/- 1.0 ng/ml, p less than 0.02) subjects. In contrast, the pituitary responsiveness to L-dopa, expressed as the relative maximum response for GH (GH delta %), was significantly higher in the latter two groups (8.5-fold, p less than 0.05, and 10.9-fold, p less than 0.02, respectively). The transfusion of packed red blood cells increased significantly Hb concentrations in both groups of thalassaemic patients (prepubertal +27%, p less than 0.05, delayed puberty +33%, p less than 0.025, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMedDate not supplied

[Heat shock proteins in diabetes mellitus].

The Heat Shock Proteins (HSP) are a special category of proteins synthesized from 2 types of cells, one originating from ordinary organs and the other highly specialized ones from mammals. Their synthesis originates from a reaction of the cells to heat shock and therefore it can be thought of as a defense mechanism activated by the cells to protect themselves from the damage done by heat. HSPs are also qualified as "molecular chaperons" since they are present at the assembling of other proteins and they protect them from any possible anomalous interactions even if they do not take an active part in the final making up of the protein itself. This chaperone role is the base of the hypothesis that HSPs could take part in the processing and presentation of the antigens. Two hypothesis have been formed on the role of HSPs in the immunological process. 1) HSP could be antigens that call for an immediate immunological reaction; 2) HSP could set off a self destructive mechanism brought on by an immunological reaction. From all this it emerges that the immunological reaction to HSP has two angles. One is protective in that it allows the cells to eliminate micro foreign-organisms and the other is harmful due to a badly regulated immunological reaction. In some studies it has been demonstrated that patients with varying autoimmunological disorders as LES and rheumatoid arthritis (AR), have autoantibodies against HSPs. Moreover the HSPs of certain microorganisms induce the formation of autoantibodies in the host and the proliferation of T cells in the synovial fluid in patients with AR.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMedDate not supplied

[The endothelium].

It is well known that the endothelial cells represent one of the most active and versatile elements in the human organism. In fact apart from being the lining of the vessel wall they exert both antithrombotic and prothrombotic functions. Endothelial cells regulate the vasomotor tone and also have a part in the different immunological and inflammatory process. All these functions are possible because the endothelial cells produce many receptors on their surface. This paper is a review of the latest data on different roles played and substances produced by endothelial cells.

Animals↗