PubMed Health⌕ Search

Biomedical subjects

A Orsetti

Publications and source records attributed to A Orsetti.

At least 37 records · Page 2Linked to original sources
PubMed1993

[Study of urinary excretion of testosterone and epitestosterone glucuronides in children and adolescents].

Urinary testosterone to epitestosterone ratio (T/E) is used as a marker for illegal exogenous testosterone use. Mean value in healthy adults is 1.13 and 6 is the upper limit of the accepted range. Urinary excretion of these two steroids were studied in 57 children and teenagers at different pubertal stages, using gas chromatography coupled with mass spectrometry with selective ion detection. Urinary excretion of testosterone and epitestosterone increased significantly during puberty. Mean T/E ratio remained fairly constant but interindividual variations were marked and in one subject the T/E ratio exceeded 6. These data suggest that this test may yield false-positive results in adolescents.

Adolescent↗
PubMed1992

Modification of the biocompatible and haemocompatible properties of polymer substrates by plasma-deposited fluorocarbon coatings.

The polymerization of gases present in a low temperature plasma is a technique particularly well suited for biomedical material processing. Therefore, the possibilities this technique offers to increase the biocompatibility and haemocompatibility of polysulphone and poly(hydroxybutyrate) membranes to be used in a new bioartificial pancreas device were studied. The deposition of thin fluorocarbon coatings from an argon plasma containing perfluorohexane gave very smooth and hydrophobic surfaces without affecting the filtering properties of the treated membranes. Adding hydrogen increased the reaction yield, but gave rougher and less hydrophobic coatings. We characterized the biological properties of the treated surfaces and discussed the influence of the modified surface properties on the biological behaviour of the treated polymers. The good biocompatibility of the deposited coatings was established by following in vitro the insulin secretion of Langerhans islets cultured on the treated membranes and by examining the fibrous capsule that developed on plasma-treated polymer disks after three months of in vivo incubation in the peritoneum of Wistar rats. Rough and haemocompatible films of poly(hydroxybutyrate) and smoother, but more thrombogenic, polysulphone films were treated by perfluorohexane and perfluorohexane + H2 plasmas to study the relative influence of surface roughness and surface energy on polymer thrombogenicity. In vitro protein adsorption and total blood clotting tests proved that the surface roughness influences the thrombogenicity more than the other surface properties. This study seems to show that the plasma deposition of smooth and hydrophobic fluorocarbon coatings can increase the biocompatibility and reduce the surface thrombogenicity of the treated membranes without affecting their filtering properties.

Animals↗
PubMed1991

[Hemorrheological parameters during normal labor and uterine contraction].

Considering the modified fluidity of blood during numerous kind of stress, the authors studied blood rheology during delivery as an example of a particularly severe stress. The authors measured blood and plasma viscosity and erythrocyte aggregation in 77 pregnant at the following stages of delivery: below 4 cm dilatation; more than 4 cm dilatation; during fetus expulsion, during after birth delivery. Apparent blood viscosity and viscosity adjusted to 45% hematocrit rose to reach a peak during expulsion (p less than 0.01) then to become normal again during placenta delivery (p less than 0.01). Hematocrit and plasmatic viscosity showed no changes during labour and expulsion. In addition erythrocyte aggregation was lowering during expulsion and delivery (stage with physiological defibrination). Rising blood viscosity might be explained by a red blood cell rigidification measured by the increasing of "Tk" (p less than 0.01) and by a nonsignificant increase of the filterability index measured by hemorheometer. In conclusion, delivery is accompanied by a blood hyperviscosity essentially related to a transient red blood cell rigidification.

Adult↗
PubMed1991

[Hemorrheological characteristics of fetal blood drawn in utero from the cord].

Extensive studies of hemorheology of cord blood (drawn just after delivery) have evidentiated a peculiar rheological pattern: less filterable red cells, reduced erythrocyte aggregation, lowered plasma viscosity. This pattern has been suggested to be important for maintaining a sufficient O2 supply to fetal tissues, by avoiding hyperviscosity despite increased RBC rigidity. However, cord blood at birth is not exactly fetal blood and we are not yet aware of studies of fetal blood drawn in utero several weeks before delivery. For this reason, we investigated the rheological properties of fetal blood during intrauterine cord venepunctures in 27 pregnant women (25-30 week's gestation) who were explored for detection of fetal genetic or infectious diseases. Fetuses have lower plasma viscosity (p less than 0.001), lower RBC flexibility (measured by filterability on the Hémorhéomètre) (p less than 0.01) and higher hematocrit/viscosity ratio (p less than 0.01) than their mothers. While no temporal modification during the studied period (20-40 wk) was detected for hematocrit and plasma viscosity, RBC filterability (rigidity) seems to exhibit a 'U shaped curve' with a nadir between 25 and 30 weeks. This pilot study supports the hypothesis that the previously reported rheological properties of cord blood at birth reflect to some extent those of intra-uterine fetal blood.

Blood Viscosity↗
PubMed1991

In vitro effects of somatostatin on red cell filterability measured by three methods.

Somatostatin is an ubiqutary neuropeptide and hormone which has been reported to exert hemodynamic effects and to bind to receptors on the red cell membrane. We investigated its effects on red cell deformability by three filtration methods: (a) filtration of red cells resuspended at hematocrit 8% in Tris-Albumin-Glucose buffer under atmospheric pressure; (b) filtration of red cells resuspended at hematocrit on native plasma at 8% hematocrit under a negative pressure of 5 cm of water; (c) filtrability of whole blood under a negative pressure of 20 cm of water. Aprotinin (Antagosan*) was added to the different suspensions in order to avoid rapid destruction of somatostatin. Increased quantities of somatostatin (from 1 pg/ml to 1 microgram/ml) were obtained by adding natural somatostatin (Modustatin*) to the media, before they were incubated at 37 C for 30 minutes. In 11 samples from healthy subjects, somatostatin was shown to increase red cell flow rate in technique (c) (+ 118%, p less than 0.05) and to reduce red cell rigidity index in technique (b) (- 71%, p less than 0.025) whereas a nonsignificant similar tendency (- 56%) was observed with technique (a). Similar results (p less than 0.05) are observed when adding somatostatin to blood of diabetics. These in vitro data suggest that somatostatin, like other previously studied hormones, may modify red cell deformability.

Erythrocyte Deformability↗
PubMed1991

Increased albumin excretion rate during a standardized exercise-test in diabetics with lowered blood filterability.

Albumin excretion rate in urine is a marker of early, reversible stages of diabetic nephropathy. Does abnormal blood rheology represent an additional risk factor in this multifactorial process? We investigated a possible link between red cell filterability and microalbuminuria during an exercise test (exercise is supposed to improve the detection of excessive microalbuminuria). 77 diabetics (27 females, 50 males, age: 15-60 yr) underwent a 20 min inframaximal progressively increasing workload on cycloergometer, rising heart rate up to 200 minus the age. Filterability of whole blood and washed red cells were measured on 5 microns polycarbonate sieves reused after ultrasonic cleaning. Whole blood filterability was found to be impaired in 35 subjects (group A) and normal in 41 (group B). Groups A and B were matched for age, sex, blood pressure, glycemic equilibrium, and duration of disease. Microalbuminuria was higher in A at rest (39.79 +/- 13.83 micrograms/min vs 12.9 +/- 3.21, p less than 0.01) and after exercise (91.80 +/- 20.79 vs 42.23 +/- 7.85, p less than 0.01). The slopes of regression lines between resting Microalbuminuria and blood pressure were greater in group A than in group B (p less than 0.01). No relationship between microalbuminuria and washed red cell filterability was detected. This study confirms on a larger scale a previous report of our team. Some hemorheologic disorders detectable with whole blood filterability (but not with washed red cell filtration) are associated with an increase in resting and postexercise microalbuminuria.

Adolescent↗
PubMed1989

Immunoreactive somatomedin C in children from Morocco: a biological marker of nutritional growth retardation?

Somatomedin C (Sm-C) is supposed to be a sensitive marker of malnutrition. Its relationship to growth and protein intake was investigated in 47 Moroccan children. The children (mean age: 7.5 +/- 2 yr) had no endocrine abnormality. Anthropometric parameters were measured, together with blood levels of Sm-C and growth hormone (GH). Lower values of Sm-C were found in the following situations: (a) growth retardation (more than -2 Sd, N = 23; Sm-C = 3.61 +/- 0.42 nmol/l vs. 13.38 +/- 1.52, P less than 0.02); (b) body weight less than 80% of expected weight for height (N = 8; Sm-C = 4.84 +/- 0.97 vs. 10.33 +/- 1.19, P less than 0.02); (c) boys with meat consumption less than 3 times per wk (N = 15; Sm-C = 4.03 +/- 0.71 vs. 12.35 +/- 2.01, P less than 0.002). Thus, lower values of Sm-C are found in association with weight insufficiency and lower protein intake. As has previously been assumed, serum Sm-C, which is regulated by nutrition, may be a sensitive tool in the assessment of nutritional status in developing countries such as Morocco. Furthermore, it could explain some cases of growth retardation in states of malnutrition.

Adolescent↗
PubMed1989

A correlation between microalbuminuria and anti-insulin antibodies in type I diabetics.

A link between circulating anti-insulin antibodies and diabetic glomerulopathy has been suggested. This paper presents two different studies aiming to detect a relationship between incipient nephropathy (indicated by microalbuminuria) and anti-insulin antibodies. In 64 type I diabetics, overnight urinary albumin excretion during an exercise-test was found to be correlated with systolic blood pressure (r = 0.258 p less than 0.05), anti-insulin antibodies (r = 0.258 p less than 0.05), and glycosylated hemoglobin (r = 0.258 p less than 0.05) whereas no correlation was found among these three parameters. In another group of 80 type I diabetics, urinary albumin excretion during a standardized exercise-test was also correlated with anti-insulin antibodies (r = 0.360 p less than 0.001). In this latter group, diabetics with elevated (greater than 200 microU/ml) levels of anti-insulin antibodies had higher values of microalbuminuria after exercise (p less than 0.001) when compared to those with lower or undetectable levels, although they did not differ with respect to blood pressure and glycemic control. Therefore, we confirm preliminary reports indicating a statistical relationship between anti-insulin antibodies and microalbuminuria. We hypothesize that anti-insulin antibodies may be an additional factor of risk in the pathogenesis of early (reversible) stages of diabetic nephropathy.

Adult↗
PubMed1987

Secondary failure of islets autotransplantation in totally pancreatectomized dogs: a multifactorial study.

Even without any immunologic barrier, as in autografts, reversal of diabetes induced by islets transplantation is not definitive and a secondary failure generally occurs. Factors involved in this failure were investigated in 13 male dogs undergoing total pancreatectomy and extemporaneous islets reinjection in the portal circulation. Five dogs died from postoperatory complications, three remained diabetic, and five were normoglycemic without insulin therapy for a duration of two to 26 weeks. Factors associated with failure appeared to be: (a) hemorrhage during dissection of pancreas prior to islets isolation, (b) imperfect collagenase digestion. Moreover, duration of this period of normoglycemia was negatively correlated with glycemia on the 20th postoperatory hour (r = 0.759, p less than 0.05), suggesting a possible relationship between glycemia and further graft outcome. Therefore, such a multifactorial statistical analysis seems to be helpful for the study of multiple technical parameters associated with the prognosis of islets transplantations.

Animals↗
PubMed1986

Investigation of drug interactions with pinaverium bromide.

A series of studies was carried out at 6 centres to investigate possible drug interaction between the spasmolytic, pinaverium bromide, and cardiac glycosides, anticoagulants and hypoglycaemic agents given to patients as part of the long-term treatment of their condition. The results of clinical and laboratory investigations did not show any evidence of pinaverium bromide interfering with the action or activity of any of the drugs studied.

Acenocoumarol↗
PubMed1986

[Comparison of biosynthetic human insulin and purified pork insulin. Studies in insulin-resistant obese patients using the insulin suppression test].

An insulin suppression test performed in random order with either biosynthetic human insulin or purified pork insulin was used to compare biological activity of these two insulins in obese patients suffering from varying degrees of glucose intolerance. Blood glucose curve, steady-state blood glucose levels, insulin sensitivity indices and steady-state plasma insulin levels were identical during the two sets of tests. Furthermore endogenous insulin and glucagon secretion were similarly suppressed. The insulin suppression test is a simple and rapid procedure to compare the biological activity of fast-acting insulins. Our results confirm the insulin-resistance in obesity and clearly show that biosynthetic human and porcine insulins have similar biological potency.

Adult↗
PubMed1986

[Secretory activity of the islands of Langerhans of newborn rats cultured in vitro on bovine corneal endothelial matrix].

Corneal endothelial cells have been shown to synthesize in vitro components of extra-cellular matrix. When the medium contains growth factors, those components reconstitute a nearly physiologic basement membrane which has been successfully used to improve several culture systems. In this work we investigated the influence of the matrix synthesized by bovine corneal endothelial cells, without growth factors, on rat neonatal pancreatic islets. After one week, islets cultivated on plastic showed a slight decrease in their insulin-releasing ability, whereas the secretory capability of islets cultivated on a matrix remained nearly constant. The difference in daily insulin release between those two culture systems reached the significance on the 20th day (p less than 0.02). Thus, such matrices could exert a favourable effect on cultured neonatal rat islets. The importance and the duration of this effect remain to be precisely determined by further investigations.

Animals↗
PubMed1986

[Secondary failure of oral antidiabetics. Value of intravenous insulin infusions].

A temporary strict blood glucose control was achieved by means of intravenous insulin infusion in 37 non insulin-dependent diabetic patients with secondary drug failure to reinduce the efficacy of oral hypoglycemic agents. This procedure was successful in 18 patients (48.6%) resulting in better glycemic response to oral hypoglycemic agents. Results remained identical 6 and 12 months later. This improvement does not seem related to an increase in insulin secretion as urinary C-peptide and basal and glucagon-stimulated plasma C-peptide were identical before and after insulin infusion. We suggest that a decrease in insulin resistance, not tested in this study, may explain the beneficial effect or normoglycemia in our patients.

Administration, Oral↗