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Biomedical subjects

M Costa

Publications and source records attributed to M Costa.

680 records · Page 38Linked to original sources
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[24 hours plasma tryptophan levels in patients with endogenous depression (author's transl)].

The variations of total and free tryptophan during 24 hours were measured in patients with endogenous depression. In depressive patients, plasma tryptophan levels are significantly lower than in control subjects. Plasma tryptophan levels in depressive patients are low during the night (when high at the same hours in normal subjects). The physiopathological mechanisms of such alterations and their possible influence on symptomathology are described.

Adult↗
PubMedDate not supplied

Studies of cyanolysis of the rhodanese-thionitrobenzoate complex.

The reaction of sulfur-free rhodanese with 5-5'-dithio-bis (2-nitrobenzoic acid) produces a modified enzyme with 35% of residual activity. The resulting enzyme derivative has 1.6 moles of thionitrobenzoate/mole of enzyme bound to sulfhydryl groups of rhodanese. Determination of free sulfhydryl groups of this derivative shows that during the reaction with 5-5'-dithio-bis (2-nitrobenzoic acid) oxidative formation of an intramolecular disulfide bridge between two sulfhydryl groups of rhodanese occurs. Cyanolysis of the modified enzyme produces an enzyme-thiocyano derivative which partially beta-eliminates with release of thiocyanate. The cleavage of disulfide bonds present in the enzyme-thionitrobenzoate adduct using labeled cyanide shows an incorporation of radioactivity in the protein higher than would be expected. An electrostatic bond between cyanide and positively charged groups of the enzyme is suggested. Most of bound cyanide is released when samples are acidified for protein hydrolysis. In these conditions the thiocyanoalanine residue cyclizes to form 2-iminothiazolidine-4-carboxylic acid.

Animals↗
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Circadian rhythm of plasma tryptophan in clinically healthy subjects and patients with endogenous depression.

Variations of plasma tryptophan along the 24-h scale are studied in clinically healthy subjects and in patients with endogenous depression. In both groups a circadian rhythm in free and total tryptophan has been found. In healthy subjects plasma tryptophan levels were higher during the night in comparison with daytime hours; the opposite was demonstrated in depressed patients. The possible physiopathological mechanisms underlying the different behavior of plasma tryptophan in the 24-h span, in these two groups of subjects, are discussed.

Adult↗
PubMedDate not supplied

The surgical correction of varicocele: multidisciplinary study on semen evaluation and prognostic factors for fertility.

The seminal pattern was studied in a group of 52 patients before and six months after sclerotherapy of varicocele. In this series, we studied the differences in clinical and seminal characteristics between the group that succeeded in obtaining a pregnancy and the group that remained infertile after 1 year follow-up. The difference in pregnancy rate is discussed between the operated group and a control group of pz, who refused any form of surgery, after 1 year follow-up.

Evaluation Studies as Topic↗
PubMedDate not supplied

L-carnitine in idiopathic asthenozoospermia: a multicenter study. Italian Study Group on Carnitine and Male Infertility.

The aim of the study described here was to evaluate any possible effect of L-carnitine on spermatozoal motility in a group of patients with unexplained asthenozoospermia in four different infertility centres. One hundred patients received 3 g d-1 of oral L-carnitine for 4 months. Sperm parameters were studied before, during and after this treatment. Motility was also studied by means of a computer-assisted sperm analysis. The results of the study indicate that L-carnitine is able to increase spermatozoal motility, both in a quantitative and in a qualitative manner (per cent motile spermatozoa increased from 26.9 +/- 1.1% to 37.7 +/- 1.1% [P < 0.001]; per cent spermatozoa with rapid linear progression increased from 10.8 +/- 0.6% to 18.0 +/- 0.9% [P < 0.001]; mean velocity increased from 28.4 +/- 0.6 microns s-1 to 32.5 +/- 0.8 microns s-1 [P < 0.001]; linearity index increased from 3.7 +/- 0.1 to 4.1 +/- 0.1 [P < 0.001], especially in the subgroup of patients with poor rapid linear progression of spermatozoa (per cent of motile spermatozoa increased from 19.3 +/- 1.9% to 40.9 +/- 1.4% [P < 0.001], and per cent of spermatozoa with rapid linear progression increased from 3.1 +/- 0.4% to 20.3 +/- 1.6% [P < 0.001]) An increase in spermatozoal output was also observed (total number of ejaculated spermatozoa increased from 142.4 +/- 10.3 10(6) to 163.3 +/- 11.0 x 10(6) [P < 0.001]). The authors conclude that oral administration of L-carnitine may improve sperm quality at least in patients with idiopathic asthenozoospermia.

Adult↗
PubMedDate not supplied

Low Ca2+ dialysate. Effects on bone metabolism in the course of paired filtration dialysis.

To evaluate the 1-year effects of PFD performed with low Ca2+ dialysate (1 mmol/l) on calcium metabolism and on bone disease, the authors studied in eight patients who were previously treated with PFD performed with standard Ca2+ dialysate (1.75 mmol/l). On samples from these subjects, the following were evaluated: 1) serum Ca2+ and PO4 levels, 2) serum PTH levels, 3) serum Al levels, and 4) bone morphology. All the patients were hypercalcemic, four with high serum PTH levels (high turnover bone disease, group 1) and four with low serum PTH levels (low turnover bone disease, group 2). In both groups, a decrease in serum Ca2+ and an increase in serum PTH was observed within the third month. In group 2, PTH levels reached the normal range. Because serum Ca2+ levels decreased to normal in both groups, it was possible to administer oral CaCO3 (10.5 +/- 2 g/day) to control serum PO4 and to stop Al gels. This did not induce any increase in serum Ca2+, whereas serum Al fell significantly. In group 1, to prevent a further rise in PTH, patients were treated with intravenous calcitriol (5 +/- 2 micrograms/week). This induced a reduction in the serum PTH without increasing serum Ca2+ or PO4. Within 12 months, an improvement in bone morphology was seen in both groups. It is concluded that the use of low Ca2+ dialysate corrects hypercalcemia in patients with PFD treated with high oral doses of CaCO3, and improves low turnover bone disease. The combination of low Ca2+ dialysate and intravenous calcitriol also improves high turnover bone disease.

Adult↗
PubMedDate not supplied

[Individualized monitoring of the therapy with gentamycin using pharmacokinetic methods. Which method to choose?].

Gentamicin has an excellent cost/efficacy ratio for gram negative infections treatment. Its use is often limited in clinical practice by its narrow safety margins and a high incidence of toxicity. Gentamicin related nephrotoxicity is a major adverse effect, mostly in patients with other concomitant potential risk factors. As many other Authors we have found in our Internal Medicine Service during 1992 a gentamicin related nephrotoxicity incidence of 22.5%. Various empiric methods and nomograms have shown a significant incidence of error in predicting individualized gentamicin dosage regimens. Pharmacokinetics methods have demonstrated much better results regarding efficacy and toxicity. The aim of this prospective study carried out during 1993-1994 was to individualize by pharmacokinetics methods dosage regimens of gentamicin in patients with one or more concomitant risk factors of nephrotoxicity. The purpose of pharmacokinetics dosage regimens has been to achieve trough serum concentrations of gentamicin in therapeutics range-0.5 to 2 micrograms/ml-on the first 24 to 48 hours of treatment, and the maintenance in this range during all the treatment, avoiding both toxic and under therapeutic levels. The incidence of gentamicin related nephrotoxicity has been evaluated in this population. Twenty patients were studied: 18 males and 2 females aged 59.6 years (19 to 85). All had one or more potential risk factors for nephrotoxicity-65 years or more: 13, previous renal failure: 6, other nephrotoxic drugs: 10, diuretics: 4, dehydration: 5, congestive heart failure: 5, diabetes: 3, hypertension: 3. For the first 10 patients gentamicin dosage regimens have been determined by Sawchuk-Zaske pharmacokinetics method and for the subsequent 10 patients by Bayesian method. The two subpopulations had no significant differences regarding mean age, sex and potential risk factors for nephrotoxicity. Results of Sawchuk-Zaske method: 53 trough gentamicin serum concentration were obtained; 86.8% were within the therapeutic range, 7.5% were toxic and 5.7% were under therapeutic. Results of Bayesian method: 44 determinations of gentamicin through concentrations were obtained; 86.3% within therapeutic range, 2.4% were toxic and 11.3% were under therapeutic. A great variability in pharmacokinetic patient's profile has been found and explains the great variability of individualized dosage regimens of gentamicin (30 to 320 mg/day). No patients had gentamicin related nephrotoxicity. Both pharmacokinetics methods lead to a efficient and save employment of gentamicin in patients with previous renal failure and other potential risk factors for nephrotoxicity.

Adult↗
PubMedDate not supplied

Intrauterine insemination with husband's semen as alternative to other assisted reproduction techniques.

The objectives of this study was to assess the efficacy and clarify how many intrauterine insemination cycles can justifiably be proposed, in terms of cost and benefits for the patient, as alternative to other assisted reproduction procedures. Two hundred and twenty infertile couples were referred to our centre and six intra-uterine insemination cycles in combination with controlled ovarian hyperstimulation were proposed for them. A total of 650 treatment cycles were completed. The indications of intra-uterine insemination were male factor (147 couples), cervical factor (31 couples), male and cervical factor (30 couples) and unexplained infertility (12 couples). Superovulation was induced in 92 patients with human menopausal gonadotrophins, in 90 with clomiphene citrate, in 22 with FSH HP, while in 16 patients the intra-uterine inseminations were carried out during spontaneous cycles. Considering the entire population, a mean monthly pregnancy rate equal to 8.9% was obtained and a cumulative pregnancy rate equal to 39% at the end of six intra-uterine insemination cycles. In particular, in the patients treated with HMG+hCG, a mean monthly pregnancy rate equal to 10.9% and a cumulative pregnancy rate to 46% at the end of the six cycles were obtained. In conclusion, when the indications allow, we believe it is justified to propose six cycles of intra-uterine insemination in combination with controlled ovarian hyperstimulation with HMG and hCG. The theoretical probability of success at the end of six cycles has proved comparable and advantageous in terms of cost and risks for the patient, if compared with other assisted reproduction techniques.

Adult↗