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Biomedical subjects

R Conti

Publications and source records attributed to R Conti.

At least 37 records · Page 2Linked to original sources
PubMed1991

Seasonal pattern of glycosylation in frog liver.

The circannual behaviour of glycosylation and protein synthesis in frog liver slices was studied following the incorporation of 3H-galactose and 14C-glucosamine into glycolipids and glycoproteins and 3H-leucine into proteins. The activity of two enzymes the galactosyl-transferase and the N-acetyl-glucosaminyl-1-P-transferase was determined. The incorporations of both sugars into the soluble fraction and into the lipid extract present a maximum during the spring-summer period. The incorporation into the protein fraction displays a different pattern: 14C-Glucosamine and 3H-leucine incorporation increases from winter to a maximum in autumn; the incorporation of 3H-Galactose has a sharp peak during spring. The pattern of glycosyltransferase activities is similar to the pattern of incorporation of the two saccharides into proteins, indicating these enzymes as important control points for glycosylation in Anurae.

Animals↗
PubMed1990

[Simvastatin versus gemfibrozil in the treatment of primary hypercholesterolemia in hypertensive patients treated with hydrochlorothiazide].

Recent pharmacological studies confirmed the role of hypercholesterolemia in the pathogenesis of coronary atherosclerosis. A 10% reduction in cholesterol levels can reduce the risk of coronary heart disease by 15%. However many hypercholesterolemic patients often suffer from arterial hypertension and drugs such as thiazide diuretics cause an imbalance in lipid metabolism. The efficacy and the tolerability of simvastatin (a inhibitor of HGM-CoA reductase) with that of gemfibrozil (a fibric acid derivative, which can reduce the VLDL level) were compared in a placebo-controlled study in 2 groups of patients with primary hypercholesterolemia and mild-to-moderate essential hypertension treated with hydrochlorothiazide. After 10 weeks standard hypolipidemic diet and hydrochlorothiazide (25 mg od) therapy, 30 patients whose cholesterol levels were still greater than or equal to 250 mg/100 ml and whose diastolic blood pressure was less than 95 mmHg were randomized to one of the following treatments: simvastatin, 20 mg od, gemfibrozil, 600 mg bid or placebo, while continuing dietetic and diuretic treatment. After 24 weeks treatment, simvastatin induced a 37% reduction in cholesterol plasma levels, a 9% increase of HDL and a 16% reduction of LDL. APO-A1 showed a 4% increase, while APO-B showed a 3% reduction. Gemfibrozil induced a 20% reduction in plasma triglycerides and a 13% decrease in plasma cholesterol, with a significant 19% increase in HDL and a 11% reduction in LDL. No significant variations in any of the lipid parameters monitored were observed in the placebo group. Treatment with simvastatin or gemfibrozil in hypertensive patients in hydrochlorothiazide monotherapy can reduce total cholesterol and LDL-cholesterol plasma levels, while significantly increasing HDL plasma levels compared to placebo. Simvastatin, however, resulted more efficient than gemfibrozil on total cholesterol or cholesterol fractions.

Adult↗
PubMed1990

[Side effects of spinal nerve root radiography. How to reduce them?].

Contrastographic techniques with intrathecal injections (SRG, Myelo-CT) are widely employed in the diagnostic approach to lumbar pathologic conditions. These techniques allow pathologic changes to be demonstrated and the information they yield helps plan the correct surgical approach. However, these invasive examinations are seldom employed for the high incidence of side-effects. The latter are related to various causes, the identification of which can help reduce the side-effects themselves. The authors analyzed a study population of 522 patients subjected to radiculography, using needles of different gauges (18-23 G), and injected non-ionic contrast medium in doses ranging 5-10 ml. The incidence of side-effects was significantly higher in the patients suffering from usual headache (79/237 = 33%), in those under 40 (87/238 = 37%), and in female patients (86/221 = 39%). The incidence of side-effects was lower with fine needles (41/139 = 17%) and contrast medium in doses less than 8 ml (80/337 = 24%). The patients were divided into 4 subgroups according to the different doses of contrast medium administered and to needle gauges: the above parameters exhibited a percentage decrease (21/161 = 14%) with 21-23 G needles and 8 ml of contrast medium. The authors believe it possible to reduce side-effects by using fine needles and smaller doses of contrast medium.

Adolescent↗
PubMed1989

Thyroid hormone effect on alpha-fetoprotein and albumin coordinate expression by a human hepatoma cell line.

The action of triiodothyronine on the production of alpha-fetoprotein and albumin in serum-free cultures of Hep G2 human hepatoma cells was examined. Our data showed that a marked inhibition (up to 8-fold) of alpha-fetoprotein secretion and an increase in albumin (up to 4-fold) are produced by 10(-8) M triiodothyronine. These effects were slow in their onset and for completion required 20-25 days of treatment with the hormone. However, an exposure of the cells to triiodothyronine for only the first 4 h was sufficient to affect, in a similar way, the secretion of alpha-fetoprotein and albumin when measured 15 days after treatment. The secretion of the two proteins parallels their intracellular levels. The decrease in alpha-fetoprotein production can be explained by a reduction of the RNA coding for the protein. The same is essentially true also for albumin increased secretion and related mRNA expression.

Albumins↗
PubMed1989

[Vitamin C in children with trisomy 21].

The present study revealed ascorbic acid deficiency in the blood of many children with Down's syndrome. It also revealed a fairly definite connection between Vitamin C deficiency and diet in these patients and a similar link between ascorbic acid deficiency and this incidence of infections. Where necessary the prescription of Vitamin C for the prevention and treatment of recurring infection is therefore recommended, bearing in mind the valuable antioxidant properties of ascorbic acid that can be exploited in combating cell deterioration.

Adolescent↗
PubMed1989

[Vertebral osteochondroma and trauma: a possible etiopathogenic correlation].

Three cases of vertebral osteochondroma are shown. The tumor was localized in the dorsal tract in two cases and in the lumbo-sacral junction in the other one. We found in all the cases, as a common anamnestic point, a clinical history of trauma. The etiopathological hypotheses are discussed and the hypothesis of a possible correlation between trauma and metaplastic osteochondromatosis is presented.

Adult↗
PubMed1987

Erythrocyte fatty acid composition and gallstone disease: results of an epidemiological survey.

Within a cross-sectional study on the epidemiology of gallstone disease (GD) and its related factors, relation of GD to habitual dietary fat types has been investigated. Gallbladder status was assessed by ultrasound; fatty acid composition of the habitual diet was estimated by GLC of erythrocyte fatty acids. No differences in erythrocyte fatty acid composition were observed between women without gallstones, women with gallstones (aware and unaware of their condition), and women who had cholecystectomies. Multivariate analysis, including other diet-dependent and gallstone-related variables, showed no significant association between erythrocyte fatty acids and risk for gallstones. However, raised erythrocyte linoleic:saturated ratio was associated with increased risk for gallstones only in women with very low serum triglycerides. This latter finding needs further confirmation and is presently unexplainable. Our results suggest that dietary fatty acids do not play a major role in GD.

Adult↗
PubMed1986

Coronary angioplasty at the time of initial cardiac catheterization.

Following initial diagnostic cardiac catheterization in 20 patients with unstable angina, percutaneous transluminal angioplasty (PTCA) was successfully performed either immediately (15 patients) or later in the day (five patients). This approach offers certain clinical and financial advantages. PTCA immediately following diagnostic catheterization should probably only be performed by experienced operators and only when excellent cooperation with cardiovascular surgeons is possible.

Adult↗
PubMed1986

Hypernociceptive syndromes and pharmacological inhibition of endogenous opioid degradation.

Endogenous opioid peptides, by modulating the release of sympathetic transmitters, may play a role in the pathogenesis of migraine and related headaches which are considered hypernociceptive syndromes. Hypoendorphinaemia has been demonstrated in migraine attack. Captopril, a drug able to potentiate morphine analgesia in rats and inhibit enkephalinase in animals and in man, improves the clinical course of migraine. In the present research the cerebrospinal fluid and plasma beta-endorphin (beta-EP) levels have been evaluated following a single oral dose of captopril. The drug increased plasma beta-EP levels in migraine sufferers, and these data may be relevant in the mechanism of action of this drug in migraine and related headaches.

Captopril↗
PubMed1986

Surgical treatment of 43 retroperitoneal sarcomas.

Forty-three cases of primary retroperitoneal sarcomas, observed and treated from 1970 to 1983 at this Institute, were analysed. The series consisted of 16 liposarcomas (37%), 10 leiomyosarcomas (23%), 7 rhabdomyosarcomas (16%), 5 fibrosarcomas (12%), 2 malignant histiocytomas (5%), 2 sarcomas NOS (5%) and 1 mesenchymoma (2%). All the patients underwent surgery. In order to evaluate the results of surgery, the patients were divided into three groups, according to the type of operation performed, that is open biopsy, resection and excision. Survival of the patients in the first group never exceeded 24 months. The symptom-free period for the patients treated by incomplete removal of the tumour (second group) lasted 3-24 months. Further surgery, in three cases for this group, did not result in a useful control of the disease. As regards radically treated cases, local recurrence was observed in 3 of the 7 liposarcomas, 2 of the 5 leiomyosarcomas, 1 of the 2 rhabdomyosarcomas and 1 fibrosarcoma. Out of 16 cases of the third group, regularly followed up, only 3 patients (liposarcomas) were alive and free of disease at 5 years from first operation. Overall 5-year survival for this group was 31.9%; disease-free survival was 18.7%. For the whole series of 43 cases, overall 5-year survival was 11.4%. As far as histology was concerned, liposarcomas showed the highest operability rate: out of 16, 7 were resected and 9 radically excised. There is a lack of convincing evidence for the utility of post-operative chemotherapy. On the contrary, post-operative radiotherapy seems to be worthwhile for liposarcomas, especially after non-radical operations.

Adult↗
PubMed1985

Prognosis of breast cancer patients after mastectomy and dissection of internal mammary nodes.

The results of the analysis carried out on data on 1119 patients with operable breast cancer treated at the National Cancer Institute of Milan from 1965 to 1979 with enlarged mastectomy are reported. Metastases to internal mammary chain were found to be significantly associated with the maximum diameter of primary (16.1% for tumors less than 2 cm and 24.5% for larger tumors, p = 0.007), the age of the patients (27.6% in patients younger than 40 years, 19.7% in patients between 41-50 years, and 15.6% in patients older than 50 years, p = 0.01). The site of origin of the cancer had no impact on internal mammary node metastases. Patients with positive axillary nodes showed metastases to internal mammary nodes in 29.1% of the cases, while 9.1% of patients with axillary negative nodes had positive retrosternal nodes. Survival was significantly affected by the presence of positive internal mammary nodes: the percentage of 10-year survival varied from 80.4% in patients with axillary and internal mammary negative nodes to 30.0% in patients with both nodal basins involved. Intermediate survival rates (54.6% and 53.0%) were found when one or the other of the nodal stations (axillary and internal mammary) was separately affected. Maximum diameter of the primary significantly affected the survival of each group identified by the status of both axillary and internal mammary nodes. In conclusion, the information on the presence or absence of internal mammary node metastases would be of great importance in formulating the prognosis of breast cancer patients. To obtain this information, a biopsy at the first intercostal space may be reasonable in selected patients (age, maximum diameter, and axillary node involvement being the basis for selection) as long as noninvasive methods of diagnosis are available.

Adenocarcinoma↗
PubMed1985

Pharmacokinetic studies on antituberculosis regimens in humans. I. Absorption and metabolism of the compounds used in the initial intensive phase of the short-course regimens: single administration study.

The absorption and metabolism of streptomycin, isoniazid, rifampicin, and pyrazinamide were evaluated after administration of each drug alone and in combination. In the combination sessions, isoniazid, rifampicin, and pyrazinamide were administered orally, either individually or in a single fixed-ratio triple preparation. The results have shown that the pattern of absorption and metabolism (acetyl-isoniazid, desacetyl-rifampicin, and pyrazinoic acid) found after administration of each drug alone did not differ from that found after administration of the drugs in free and fixed combination. The 3 orally administered drugs given in a fixed combination resulted in a reduction of the order of 50% of the total number of tablets to be ingested.

Absorption↗
PubMed1984

Pharmacokinetic study on intravenous rifampicin in man.

A pharmacokinetic study was carried out in 18 male patients in order to assess the blood concentrations of rifampicin after intravenous administration of 3 different doses (600, 900 and 1200 mg) over 3 different periods of infusion (1, 2 and 3 hours). The results show that, by increasing the dose and the rate of infusion higher and earlier peak concentrations are obtained. A kinetic analysis based on a one-compartment open model gives a good fitting of the data obtained experimentally. From these data one obtains for the volume of distribution a value of 48.1 +/- 17.2 liters and for the serum disappearance rate the value of 0.212 +/- 0.070 h-1 in adult subjects. It is possible to predict the time course of serum kinetics of the drug by using the equation (formula; see text).

Bilirubin↗
PubMed1982

Mutagens in urine of carbon electrode workers.

Following previous work carried out in an Italian factory producing carbon electrodes and evaluating the occupational mutagenic-carcinogenic hazards, the authors studied the presence of mutagen metabolites in the urine of workers in the same factory who were exposed to petroleum coke and pitch and in the urine of a control group of unexposed workers. The urine samples were concentrated by absorption on XAD-2 columns and were tested using the Salmonella/microsome assay (strain TA 98, TA 100, TA 1535, TA 1538) with and without the addition of beta-glucuronidase and metabolizing system. The collection of urine samples was carried out twice, with an interval of 2 months; "before working time", "after working time", and also during Sunday. The results showed that (1) urine samples collected "before" occupational exposure (upon waking) or on Sunday revealed no mutagenic activity in either worker groups and (2) that the urine samples collected after or during occupational exposure revealed high mutagenic activity in the exposed workers, with a statistically significant difference (P less than 0.05) between the mean of the revertants/plate values for exposed and unexposed workers. On the basis of the previous and the present research, the authors suggest that application of the Salmonella/microsome test to work environments could offer useful and suitable tool for evaluating the health hazards due to mutagenic/carcinogenic substances from occupational exposure.

Carbon↗