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Biomedical subjects

G Gatti

Publications and source records attributed to G Gatti.

At least 73 records · Page 4Linked to original sources
PubMed1998

[Varicocele and its repercussion on infertility. Indications and limitations of surgical intervention].

According to different Authors, varicocele incidence in unselected population fluctuates from 8 to 22% but in selected population affected by sterility incidence ranges from 21 to 39%. However other Authors have demonstrated that about 50% of patients suffering from varicocele have semen alterations. Various mechanisms have been suggested for testicular dysfunction associated with varicocele: intrascrotal hyperthermia, reflux of renal and adrenal metabolites from the renal vein and hypoxia. The most important semen alterations are observed in patients suffering from grade 2 and 3 varicocele and especially these patients must undergo surgical operation. According to recent findings, better results about the improvement of semen quality are obtained by operating children in puberal age. This clinical approach allows a prevention of testicular hypotrophy or, when this is already present, its reversibility. Varicocele surgical treatment makes use of traditional techniques microsurgical or not and mininvasive techniques. After renouncing of intrascrotal varicocelectomy, traditional techniques provide ligature and section of ectasic spermatic veins, after a surgical high (at level of the internal inguinal ring) or low (over inguinal canal) skin incision. Microsurgery allows recognition and protection of lymphatic and arterial vessels and execution of microsurgical anastomosis between venous spermatic and ileo-femoral circle vessels, when this is necessary. Internal spermatic vessels and vas deferens can be visualized through the laparoscope and so laparoscopic varicocele treatment was suggested. These new techniques and traditional operation are burdened with the same percentage of relapses but in laparoscopic procedure complications are more important. Recently radiographic occlusion techniques are also utilized (internal spermatic vein retrograde scleroembolization); the percentage of relapses is between 4 and 11%, with no risk of postvaricocelectomy hydrocele but with risk of loss of kidney (migration of the ballon or coil into the renal vein). Surgical treatment of varicocele produces a significant improvement in semen analysis in 60 to 80 per cent of patients affected by testicular dysfunction. Pregnancy rates after varicocelectomy are including from 20 to 60 per cent with most series averaging about 35 per cent.

Adolescent↗
PubMed1998

[Andrologic surgery].

The need of an economic and social low costs drive more and more surgeons towards the day surgery. The always growing diffusion of local anesthetic supports this trend. The drugs used as local anaesthetics are: carbocaine, procaine, lidocaine and bipivacaine. The Day Surgery can be largely employed in the therapy of andrological pathologies. In fact the anatomical placement of male genital apparatus allows easy possibilities of anaesthetical and surgical approach. It is so possible perform the following operations: meatotomy, section and plasty of fraenum, extirpation of Papovavirus lesions, circumcision, paraphymosis setting, corpora cavernosa drainage in priapism, section and ligation of deep dorsal vein, corporopexi, glandulopexi, cavernous crural plication, endocavernous penile prosthesis' implant, congenital or acquired penile recurvatum correction, blandulectomy, hepidydimis' cyst excision, testicle's biopsy, subcapsular orchiectomy sec. Higgins, testicular prosthesis' implant, resection and eversion of vaginal tunic of testicle in hydrocele's therapy, vasotomy and section and ligation of internal spermatic vein in varicocele's surgery. The Authors describe the anaesthetical and surgical techniques for bring forward these operations in Day Surgery.

Adult↗
PubMed1997

Diagnosis of Hill-Sachs lesion of the shoulder. Comparison between ultrasonography and arthro-CT.

AIM: The Hill-Sachs lesion is a compression fracture caused by impact on the trabeculae of the humeral head during anterior glenohumeral dislocation. The early and accurate identification of patients who risk recurrence of shoulder dislocation requires a suitable screening method. This should be characterized by high sensitivity and specificity, low cost, and repeatability. MATERIAL AND METHODS: The results of ultrasound examination as a screening method were evaluated, the indicator being the identification of the Hill-Sachs lesion. Using ultrasonography and conventional radiological techniques, and double contrast CT (arthro-CT), we studied 60 patients with posttraumatic instability of the shoulder. RESULTS: Against arthro-CT as the true standard, ultrasonography showed a sensitivity of 95.6%, specificity of 92.8%, and diagnostic accuracy of 95%. CONCLUSION: Ultrasonography is an acceptable screening examination for recurrent scapulohumeral dislocation and should be applied prior to other techniques of investigation such as arthro-CT or MR imaging.

Adult↗
PubMed1997

Overexpression of calsequestrin in L6 myoblasts: formation of endoplasmic reticulum subdomains and their evolution into discrete vacuoles where aggregates of the protein are specifically accumulated.

Calsequestrin (CSQ), the major low-affinity Ca(2+)-binding glycoprotein of striated muscle fibers, is concentrated to yield aggregates that occupy the lumen of the terminal cisternae of the sarcoplasmic reticulum (SR). When infected or transfected into L6 myoblast, the protein is also concentrated, however, in dense vacuoles apparently separate from the endoplasmic reticulum (ER). CSQ-rich cells appear otherwise normal; in particular, neither other proteins involved in Ca2+ homeostasis nor ER chaperones are increased. The CSQ dense vacuoles are shown herein to be specialized ER subdomains as demonstrated by 1) the endoglycosidase H sensitivity of their CSQ and 2) two markers, calreticulin and calnexin (but not others, protein disulfide isomerase and BiP), intermixed with the vacuole content. Their formation is shown to start with the aggregation of CSQ at discrete sites of the ER lumen. When cells were transfected with both CSQ and calreticulin, only the first gave rise to vacuoles; the second remained diffusely distributed within the ER lumen. The possibility that CSQ aggregation is an artifact of overexpression appears unlikely because 1) within dense vacuoles CSQ molecules are not disulfide cross-linked, 2) their turnover is relatively slow (t = 12 h), and 3) segregated CSQ is bound to large amounts of Ca2+. Transfection of a tagged CSQ into cells already overexpressing the protein revealed the continuous import of the newly synthesized protein into preassembled vacuoles. The tendency to aggregation appears, therefore, as a property contributing to the segregation of CSQ within the ER lumen and to its accumulation within specialized subdomains. The study of L6 cells expressing CSQ-rich vacuoles might thus ultimately help to unravel mechanisms by which the complexity of the sarcoplasmic reticulum is established in muscle fibers.

Animals↗
PubMed1997

Penetration of dapsone into cerebrospinal fluid of patients with AIDS.

It has been proposed that dapsone in combination with pyrimethamine could be used for prophylaxis of both Pneumocystis carinii pneumonia and encephalitis due to Toxoplasma gondii. Ten patients with AIDS undergoing lumbar puncture for diagnostic purposes were studied in order to assess the penetration of dapsone into CSF. Blood and CSF samples were obtained between 3 and 72 h following administration. Six patients had received oral dapsone for at least 1 month at the dosage regimen of 100 mg twice of three times weekly and four patients had received a single oral 100 mg dose. Dapsone concentration in CSF ranged from 0.013 to 0.296 mg/L while concentrations in plasma ranged from 0.018 to 1.231 mg/L. The CSF:plasma concentration ratio ranged from 0.21 to 2.01. The MIC of dapsone in combination with pyrimethamine against T. gondii is unknown, and further data are required to confirm whether the CSF concentrations of dapsone found in our study are sufficient to inhibit T. gondii growth in patients infected with human immunodeficiency virus (HIV). The high interpatient variability of dapsone CSF concentrations warrants further studies in selected categories of patients with HIV infection.

Acquired Immunodeficiency Syndrome↗
PubMed1997

A rapid and specific assay for the determination of lamotrigine in human plasma by normal-phase HPLC.

A rapid and specific high-performance liquid chromatography assay of lamotrigine in human plasma is described. Lamotrigine is extracted with dichloromethane from buffered plasma to which an internal standard has been added. The solvent is directly injected into a 250 x 4.6-mm Spherisorb Silica column and the drug is eluted by using a mixture of methanol, n-heptane, dichloromethane, and 28-30% ammonium hydroxide (20:40:40:0.3 vol/vol) at a flow rate of 1 ml/min. The eluates are detected at 240 nm. The assay requires 250 microliters of sample, and concentrations as low as 0.4 microgram/ml can be measured accurately. The method is linear in the range of 0.4-16 micrograms/ml, with a mean coefficient of correlation (r) > or = 0.997. Within- and between-day relative standard deviations at three different concentration levels (1, 4, and 8 micrograms/ml) are < or = 8.6%.

Anticonvulsants↗
PubMed1997

The influence of dosage, age, and comedication on steady state plasma lamotrigine concentrations in epileptic children: a prospective study with preliminary assessment of correlations with clinical response.

The effects of age, dosage, and type of comedication on plasma lamotrigine (LTG) concentrations and the relationship between plasma drug levels and clinical response were evaluated in a prospective study of 45 patients, aged 3 to 38 years, with epilepsy uncontrolled by conventional anticonvulsant therapy. Six of the 45 patients were on single-drug therapy, and 39 were on two to five concurrently administered antiepileptic drugs when LTG was added. Thirteen patients were assessed at three or more LTG dosage levels. Within individuals, steady state plasma LTG concentrations increased linearly with increasing daily dosage over the examined dose range (25 to 575 mg/day or 0.75 to 21 mg/kg.day). Among patients also receiving enzyme-inducing agents, such as carbamazepine, barbiturates, or phenytoin, plasma LTG concentrations normalized to a 1 mg/kg daily dose were lower in children aged 3 to 6 years (0.30 +/- 0.17 microgram/ml; n = 6) than in the older children (0.43 +/-0.18 microgram/ml; n = 12) and adolescents/adults (0.68 +/- 0.26 microgram/ml; n = 10). In patients treated with valproate, the age dependency of plasma LTG was less evident, possibly because of a smaller sample size and the confounding effect of comedication. Within any given age group, dose-normalized LTG concentrations were about five-fold higher in patients comedicated with valproic acid than in those comedicated with enzyme inducers. Twenty patients showed a favorable response (with a > or = 40% reduction in seizure frequency compared with the pre-LTG period) and continued on long-term treatment. Plasma drug concentrations in these apparent responders were highly variable and did not differ significantly from those observed in nonresponders (6.6 +/- 5.2 versus 4.8 +/- 3.3 microgram/ml). These findings show that plasma LTG concentrations exhibit a wide interindividual variability under the influence of age and type of comedication, but they are predictably related to dosage within individual patients. Although there was no apparent relationship between drug levels and clinical response in this difficult-to-treat population, further studies on the potential value of monitoring plasma LTG concentrations are indicated.

Adolescent↗
PubMed1997

A double-blind, placebo-controlled study on the effect of vigabatrin on in vivo parameters of hepatic microsomal enzyme induction and on the kinetics of steroid oral contraceptives in healthy female volunteers.

PURPOSE: This study was conducted to determine whether vigabatrin affects in vivo indices of hepatic microsomal enzyme activity and the pharmacokinetics of steroid oral contraceptives in healthy subjects. METHODS: Under double-blind conditions, 13 female healthy volunteers received, in random order and with a washout interval of > or = 4 weeks, two oral 4-week treatments with vigabatrin (VGB) (maintenance dosage, 3,000 mg daily) and placebo, respectively. The clearance and half-life of antipyrine (a broad marker of drug oxidation capacity), the urinary excretion of 6-beta-hydroxycortisol (a selective marker of cytochrome CYP3A-mediated oxidation), and the activity of serum gamma-glutamyltransferase (a nonspecific index of microsomal enzyme activity) were determined after 3 weeks of each treatment. The single-dose kinetics of a combined oral contraceptive containing 30 micrograms ethinyl estradiol and 150 micrograms levonorgestrel were also determined after 3 weeks of treatment by specific radioimmunologic assays. RESULTS: VGB treatment had no influence on antipyrine clearance (28 +/- 5.6 vs. 30 +/- 4.5 ml/h/kg on placebo), antipyrine half-life (15.5 +/- 3.5 vs. 14.1 +/- 2.1 h), urinary 6-beta-hydroxycortisol excretion (488 +/- 164 vs. 470 +/- 228 nmol/ day), 6-beta-hydroxycortisol-to-cortisol concentration ratio (6.8 +/- 3.1 vs. 6.1 +/- 3.1) and serum gamma-glutamyltransferase activity (12 +/- 3 vs. 11 +/- 3 IU/L). No difference in pharmacokinetic parameters between VGB and placebo sessions were found for ethinyl estradiol (half-life, 12.5 +/- 3.2 vs. 13.9 +/- 3.2 h; AUC, 874 +/- 301 vs. 939 +/- 272 ng/ L/h) and levonorgestrel (half-life, 17.7 +/- 5.2 vs. 23.1 +/- 9.8 h; AUC, 27.5 +/- 9.6 vs. 30.0 +/- 12.0 micrograms/L/h). Two subjects, however, showed a 50 and a 39% reduction in ethinyl estradiol AUC during VGB treatment. CONCLUSIONS: At therapeutic dosages, VGB did not modify in vivo indices of hepatic microsomal enzyme activity and did not interfere significantly with the CYP3A-mediated metabolism of ethinyl estradiol and levonorgestrel. Based on these data, VGB is unlikely to affect consistently the efficacy of steroid oral contraceptives or interact pharmacokinetically with drugs that are eliminated mainly by oxidative pathways, particularly those involving cytochrome CYP3A.

Adult↗
PubMed1997

Penetration of dapsone into pulmonary lining fluid of human immunodeficiency virus type 1-infected patients.

We studied the penetration of dapsone into the epithelial lining fluid (ELF) of sixteen human immunodeficiency virus type 1-infected patients who had received the drug at a dose of 100 mg twice weekly as primary prophylaxis for Pneumocystis carinii pneumonia. Bronchoscopy, bronchoalveolar lavage (BAL), and venipuncture were performed for each patient at a specific time after administration of the last dose of dapsone. Dapsone concentrations in plasma and BAL were determined by high-performance liquid chromatography. The apparent volume of ELF recovered by BAL was determined by using urea as an endogenous marker. The mean concentrations of dapsone in ELF at 2 h (five patients), 4 h (three patients), 12 h (two patients), 24 h (three patients), and 48 h (three patients) were 0.95, 0.70, 1.55, 0.23, and 0.45 mg/liter, respectively, while concentrations in plasma were 1.23, 0.79, 1.31, 0.83, and 0.18 mg/liter, respectively. Dapsone concentrations in ELF were 76, 79, 115, 65, and 291% of those observed in plasma at the same times, respectively. These data show that dapsone is well distributed into ELF and that a twice-weekly 100-mg prophylactic regimen results in sustained concentrations in this compartment.

Adult↗
PubMed1997

Acute mastoiditis with complications: a report of two cases.

The authors report two cases of lateral sinus thrombosis (LST) which were recently observed after more than a 20-year absence of such pathology at their Institutions. After reviewing the epidemiologic data, the clinical observations are described in detail. Changes in symptomatology mainly due to the improper use of antibiotics are then discussed as well as the diagnostic improvement offered by modern imaging techniques. Problems still under debate concern the therapeutic strategy: internal jugular vein ligation or anticoagulation therapy versus aminoglycoside administration for patients refractory to the conventional antibiotic therapy. The necessity of close cooperation between general practitioner, pediatrician and otolaryngologist is stressed.

Acute Disease↗
PubMed1996

Pharmacokinetics of antimicrobial agents in the respiratory tract.

The ability of antibiotics to penetrate into the respiratory tract has been investigated at several sites, namely, sputum and bronchial secretions, tissue homogenates, pleural fluid and, more recently, epithelial lining fluid and alveolar macrophages. The major reason for such investigations is that these data may be helpful to a more thorough understanding of drug distribution in the lung tissue and fluids and to a more accurate prediction of clinical outcome. However, the study of drug concentration at each of these sites presents problems in terms of methodology and data interpretation. The advantages and disadvantages of each of these methods are considered, and the data on penetration of betalactams, aminoglycosides, macrolides, fluoroquinolones and other antimicrobial agents (including antifungal and antiprotozoan drugs) are reviewed.

Animals↗
PubMed1996

Effect of enzyme inducing anticonvulsants on ethosuximide pharmacokinetics in epileptic patients.

1. To assess the effect of enzyme inducing anticonvulsants on ethosuximide pharmacokinetics, plasma ethosuximide concentrations after a single oral dose (500 mg) of the drug were compared in 12 healthy control subjects and 10 epileptic patients receiving chronic therapy with phenobarbitone, phenytoin and/or carbamazepine. 2. Compared with controls, epileptic patients showed markedly shorter ethosuximide half-lives (29.0 +/- 7.8 vs 53.7 +/- 14.3 h, means +/- s.d., P < 0.001) and higher apparent oral clearance (CL/F) values (15.3 +/- 3.8 vs 9.2 +/- 1.9 ml kg-1 h-1, P < 0.001). The apparent volume of distribution (V/F) of ethosuximide was slightly lower in the patients than in controls (0.6 +/- 0.1 vs 0.7 +/- 0.1 l kg-1, P < 0.05). 3. These findings provide evidence that ethosuximide elimination is increased by enzyme inducing anticonvulsants, the effect probably being mediated by stimulation of cytochrome CYP3A activity. 4. The enhancement of ethosuximide clearance in patients comedicated with enzyme inducing anticonvulsants is likely to be clinically relevant. Higher ethosuximide dosages will be required to achieve therapeutic drug concentrations in these patients.

Adult↗
PubMed1996

High-dose fluconazole therapy for cryptococcal meningitis in patients with AIDS.

Fluconazole (800-1,000 mg i.v.) was administered to 14 consecutive patients with AIDS and cryptococcal meningitis. At 10 weeks the rate of clinical success was 54.5% (six of 11 patients responded to fluconazole); the Kaplan-Meier estimate of the response rate was 67.1%, and the overall mortality rate was 18.2% (two of 11 patients died). At the end of treatment, eight (72.7%) of 11 patients responded to fluconazole. The median time to the first negative cerebrospinal fluid (CSF) culture was 33.5 days (95% confidence interval, 18.3-67.3); the median time for patients with initial CSF cryptococcal antigen titers of > or = 1:1,024 was 66 days compared with 18 days for patients with initial CSF cryptococcal antigen titers of < 1:1,024 (P = .06). The median time to the first negative CSF culture for patients with an isolate for which the minimum inhibitory concentration (MIC) was 4 micrograms/mL was 56 days compared with 16 days for patients with an isolate for which the MIC was < 4 micrograms/mL (P = .11). The mean serum and CSF levels of fluconazole at steady state were 42.47 +/- 26.31 micrograms/mL and 36.63 +/- 21.08 micrograms/mL, respectively (ratio of CSF:serum, 0.86). No treatment was interrupted and no dose was tapered because of side effects. High-dose fluconazole might be an effective and well-tolerated therapeutic option for patients with AIDS and acute cryptococcal meningitis.

AIDS-Related Opportunistic Infections↗
PubMed1996

Penetration of vancomycin into human lung tissue.

Vancomycin penetration into lung tissue was evaluated in thirty patients following the administration of 1 g of vancomycin as a 1 h i.v. infusion. Mean concentrations (range) of vancomycin in lung tissue were 9.6 (6.3-12.1) mg/kg at 1h, 5.7 (4.7-7.4) mg/kg at 2 h, 4.2 (0.8-6.5) mg/kg at 3-4 h, 2.4 (1.4-4.7) mg/kg at 6 h, and 2.8 (0.9-7.8) mg/kg at 12 h after the end of infusion. Ratios of lung tissue to serum concentration ranged 0.24 to 0.41 at 1 and 12 h, respectively. One of six patients observed at 6 h, and 3 of 7 patients at 12 h did not have detectable levels of vancomycin in lung tissue. A 1 h iv infusion of a 1 g dose of vancomycin does not achieve sustained lung concentrations above the MIC for susceptible staphylococci over a dosing interval of 12 h. Therefore, a more appropriate modality of administration, such as continuous infusion, should be considered.

Aged↗
PubMed1996

The influence of ethnic factors and gender on CYP1A2-mediated drug disposition: a comparative study in Caucasian and Chinese subjects using phenacetin as a marker substrate.

To assess potential ethnic and gender-related differences in the expression of cytochrome CYP1A2-mediated activity, the pharmacokinetics of phenacetin (a CYP1A2 substrate) and its metabolite paracetamol were compared in 20 Caucasian and 20 Chinese subjects after administration of a single oral 900 mg phenacetin dose. Peak plasma concentrations and apparent oral clearance values for phenacetin did not differ between the two groups (geometric means: 3.4 micrograms/ml and 1.56 ml h-1 kg-1, respectively, for Caucasians vs. 4.7 micrograms/ml and 1.25 ml h-1 kg-1, respectively, for Chinese, after excluding one Caucasian with aberrantly low plasma phenacetin values). Pharmacokinetic parameters for metabolically derived paracetamol were also similar in the two groups. When subjects were divided into subgroups according to gender, phenacetin apparent oral clearance values were found to be lower in Chinese women compared with both Chinese men and Caucasian subjects of either sex. It is concluded that there are no major interethnic differences in the expression of CYP1A2-related activity between Caucasians and Chinese, although Chinese women as a subgroup may exhibit comparatively lower enzyme activity.

Acetaminophen↗
PubMed1996

Reduced plasma nisoldipine concentrations in phenytoin-treated patients with epilepsy.

PURPOSE: To assess whether phenytoin affects the pharmacokinetics of the dihydropyridine calcium antagonist nisoldipine. METHODS: Twelve patients with epilepsy receiving chronic phenytoin therapy and 12 healthy control subjects matched for age and gender received a single oral dose of nisoldipine (40 and 20 mg, respectively). Blood samples were collected for up to 48 h for estimation of plasma nisoldipine levels by capillary gas chromatography. RESULTS: Mean plasma nisoldipine concentrations were much lower in the patients. Geometric means for areas under the concentration-time curve (AUC0-tn) normalized to a 20-mg dose were 1.6 micrograms/L/h (95% confidence intervals, 0.6-3.8 micrograms/L/h) in the patients compared with 15.2 (10.7-21.6) micrograms/L/h in control subjects (p < 0.002). CONCLUSIONS: These results suggest that phenytoin increases the first-pass metabolism of nisoldipine to a clinically important extent. In view of the magnitude and variability of interaction, use of nisoldipine in patients receiving chronic phenytoin therapy is contraindicated.

Adult↗