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Biomedical subjects

A Conte

Publications and source records attributed to A Conte.

At least 55 records · Page 3Linked to original sources
PubMed1996

A comparative study between etiological factors of calcium oxalate monohydrate and calcium oxalate dihydrate urolithiasis.

A comparative study between different etiological factors of calcium oxalate monohydrate (COM) and calcium oxalate dihydrate (COD) is presented. The most frequent alteration in COD urolithiasis was associated with hypercalciuria, whereas in COM urolithiasis was associated with urinary pH. A comparison between COM and COD groups of stone formers that exhibited 1, 2 or 3 alterations was performed. Thus, in individuals with two simultaneous alterations, the association between altered urinary pH and hypomagnesiuria was the most frequent in the COM group, whereas the association between hypercalciuria and altered urinary pH was most frequent in the COD group. In individuals with three simultaneous alterations, the association between hypercalciuria, hyperphosphaturia and hyperuricuria was most frequent in both COM and COD stone formers.

Analysis of Variance↗
PubMed1996

[Difficult digestive hemorrhage: angiodysplasia].

The authors report 7 cases of ileal and colonic angiodysplasia observed over a 3 year period (1992-1994). After a review of literature concerning etiology, pathology, diagnosis, and treatment emphasize the use of angiography for preoperatory diagnosis an intraoperatory localization of the lesion when this one is localized in the ileum. After review of usefull therapies, they stress the role of surgery as the most used therapy and only really complete.

Adult↗
PubMed1995

Nitric oxide synthase activity in molluscan hemocytes.

The hemocytes of the freshwater snail Viviparus ater have nitric oxide synthase (NOS) activity, as demonstrated by [3H]citrulline and nitrite + nitrate formation. The enzyme is NADPH dependent and is competitively inhibited by the mammalian NOS inhibitor NG-monomethyl-L-arginine (Ki = 4.7 microM). The Km for L-arginine is 2.5 microM. 70% of the total activity is observed at very low free Ca2+ concentration (3 nM). LPS treatment increased total NOS activity 2.4 fold. The activity is partly present in the non-soluble fraction of hemocytes (24% and 8% in non-stimulated and LPS-stimulated snails, respectively). An antiserum to the C-terminal synthetic pentadecapeptide of the rat cerebellar NOS inhibited the enzyme activity in a concentration-dependent manner. This is the first biochemical demonstration of the existence of NOS activity in molluscan hemocytes, the cells responsible for defence mechanisms.

Amino Acid Oxidoreductases↗
PubMed1995

Nitric oxide: an ancestral immunocyte effector molecule.

The presence and the role of nitric oxide synthase (NOS) were investigated in the molluscan hemocytes by immunocytochemical, biochemical and functional approaches. Using an anti-NOS polyclonal antibody, immunoreactivity was observed in the hemocytes, and this reactivity increased after stimulation of the animals with Escherichia coli, indicating that this enzyme is inducible. The NOS inducibility was also histochemically demonstrated by detection of NADPH-diaphorase activity. Biochemical studies show that the enzyme is 70% cytoplasmatic and 30% membrane bound and that the inducible form is mainly cytoplasmatic. The nitrite + nitrate and citrulline formation, the inhibition by N omega-nitro-L-arginine, the Km value for arginine, the calcium and co-enzyme dependence show that the molluscan NOS shares the same properties as the NOS isoenzymes so far studied. However, it cannot be identified with any of these enzymes. It appears to be in some way similar to an inducible form of human hepatocyte NOS. Also cytokines are able to induce NOS. In vitro studies have shown that hemocytes produce nitric oxide (NO), a bactericide substance, and that there is a relationship between the NO system and phagocytosis. The presence of NO in the invertebrate hemocyte demonstrates that critical molecules have been conserved over the course of evolution.

Animals↗
PubMed1995

Classical Kaposi's sarcoma: a survey of 163 cases observed in Bari, south Italy.

BACKGROUND: Classical Kaposi's sarcoma (KS) is a sporadic disease that is particularly prevalent in Mediterranean countries. OBJECTIVE: The aim of the study was to update clinical information about this rare condition. METHODS: A survey of 163 cases observed in the period 1971-1990 in Bari, South Italy, was carried out. All records were reviewed and, when lost to follow-up for more than 6 months, patients were called back to update personal and family histories. The age at onset averaged 64 years (range 18-85). The male-to-female ratio was 3:1. No familiar occurrence was identified, and no significant association was found with other conditions (i.e. second primary malignancies and diabetes mellitus). Death from KS occurred in 16 cases, at the mean age of 71 years, an average of 5.7 years after the onset of the disease. To assess whether the different clinical patterns of the disease in its earlier stages may give any indication of its subsequent clinical course, all cases were re-classified into three groups (low-, moderate- and high-eruptivity group) on the basis of both the extent and the rate of spread of the disease before first admission; group-stratified survival function was evaluated using Kaplan-Meier's life table method. RESULTS: Highly significant (p < 0.0001) differences were found in survival profiles of the three study groups, also when only deaths due to KS were computed. CONCLUSION: These findings provide some support to the hypothesis that three subsets of classical KS exist that have different prognoses and, consequently, need different therapeutic approaches.

Adolescent↗
PubMed1995

Effect of L-propionyl carnitine on some properties of erythrocytes and leukocytes of alcohol abusers.

The effect of L-propionyl carnitine, the carnitine derivative utilized as a more effective drug for membrane protection, on Na-K ATPase activity of erythrocyte ghosts of alcohol-dependent patients and blood donors has been investigated. The effect of L-propionyl carnitine on leukocyte chemotaxis and cytochrome c reduction, a measure of superoxide ion production was also studied. It has been in fact observed that alcohol is immunotoxic on both the non-specific and the specific immune response. In alcohol-dependent erythrocytes, a significant higher value of the 1H-NMR spin lattice relaxation time (T1) was observed as compared to blood-donor erythrocytes. The in-vitro addition of ethanol increases the T1 values of blood donor erythrocytes, whereas it is without effect on the T1 value of alcohol-dependent erythrocytes. The Na-K ATPase activity is higher in alcohol-dependent erythrocyte ghosts as compared to blood-donor ghosts. A non-significant increase of the Na-K ATPase activity of blood-donor ghosts was observed with the increasing of L-propionyl carnitine concentrations (from 0.2 to 5.0 mM), whereas the Na-K ATPase activity of alcohol-dependent ghosts decreases. From these combined effects the differences of Na-K ATPase activity progressively decrease with the increasing of L-propionyl carnitine concentration, and no significant differences are observed between the two groups at L-propionyl carnitine concentrations higher than 0.5 mM. The in-vitro addition of ethanol increases the enzyme activity to a greater extent in blood-donor ghosts as compared to alcohol-dependent ghosts. This in-vitro activation by ethanol is decreased by the addition of L-propionyl carnitine. The chemotaxis induced by N-formyl-methionyl-leucylphenylalanine and the superoxide anion production stimulated by zymosan is significantly lower in alcohol-dependent neutrophils. L-Propionyl carnitine increases, in a dose-dependent way, both chemotaxis and superoxide anion production of alcohol-dependent neutrophils, and no significant difference was observed between the two groups at 5 mM L-propionyl carnitine. These experimental results suggest that L-propionyl carnitine administration may be useful for reducing some acute and chronic damages due to alcohol ingestion. The protective and modulatory actions of L-propionyl carnitine may be even more evident in cells and tissues different from those investigated in this study and in which ethanol determines several biochemical damages.

Alcoholism↗
PubMed1995

Biochemical and pharmacokinetic aspects of oral treatment with chondroitin sulfate.

Chondroitin sulfate (Condrosulf) was characterized for structure, physiochemical properties and purity. This glycosaminoglycan has a relative molecular mass of about 14,000, a sulfate-to-carboxyl ratio of 0.95 due to the high percentage of monosulfated disaccharides (38% 6-monosulfate and 55% 4-monosulfate) and a low amount of disulfated disaccharides (1.1%) inside the polysaccharide chains. No other glycosaminoglycans were detected in the preparation. Chondroitin sulfate was labelled by reduction with sodium 3H-borohydride and administered by oral route in the rat and dog. More than 70% of radioactivity was absorbed and found in urine and tissues. The plasma radioactivity was fractionated by size-exclusion chromatography in three fractions: radioactivity associated with high, intermediate and low molecular mass compounds. The peak value of the concentration of high molecular mass radioactivity compounds in plasma was reached after 1.6 and 2.1 h for the rat and dog, respectively. After 36 h the high molecular mass radioactivity compounds were still present in plasma of dog and rat. After 24 h radioactivity was higher in the intestine, liver, kidneys, synovial fluid and cartilage than in other tissues. Condroitin sulfate was orally administered to man (healthy volunteer) in a single daily dose of 0.8 g and in two daily doses of 0.4 g. The results showed that both forms of administration determined a significant increase of plasma concentration of chondroitin sulfate as compared with predose value over a full 24 h period. Elimination constant values and tmax (of the first administration in the case of fractionated dose) were almost the same for the two administrations.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Effects of glycosaminoglycans on U-937 leukemia cell proliferation and differentiation: structure-function relationship.

Glycosaminoglycans (heparins, dermatan sulfate, chondroitin sulfate) with different structures and physicochemical properties were evaluated for their capacity to influence proliferation and differentiation of U-937 cell line. The contrasting and specific effects of glycosaminoglycans (depending on their structures and properties) on a leukemia cell line could help explain the regulation of proliferative and/or differentiative processes of hematopoietic cells in order to clarify the control of development and differentiation of hematopoietic progenitor cells by bone marrow extracellular matrix. Heparin from beef intestinal mucosa, heparan sulfate from beef spleen, dermatan sulfate from beef intestinal mucosa, and chondroitin sulfate from bovine trachea were extracted and purified, and their purity, structures, and physicochemical properties were evaluated. Fast-moving heparin was obtained by its selective precipitation as barium salt, and partially desulfated and re-N-sulfated heparin was produced by chemical modifications. Different glycosaminoglycans were tested to evaluate their effects on proliferation and differentiation processes of a monoblastic leukemia cell line (U-937). Heparin and derivatives (from 0.1 to 100 micrograms/ml) inhibit cell proliferation; heparan sulfate does not produce modifications, while chondroitin sulfate and dermatan sulfate (from 0.01 to 100 micrograms/ml) significantly stimulate cell growth. Cell differentiation was evaluated by cytoenzymatic determination of alpha-naphthyl butyrate esterase and by fluorescein-labeled anti-HLA-DR, anti-CD11b, and anti-CD14 antibodies. Nitro blue tetrazolium reduction and phagocytosis were also evaluated. Heparin and derivatives significantly increase U-937 differentiation. Heparin sulfate has no effect, while chondroitin sulfate and, to a lesser extent, dermatan sulfate, induce a strong decrease of differentiative markers. The regulation of U-937 cell properties appears to be related to charge density and to the amount of N-sulfate and N-acetyl groups. In particular, glycosaminoglycans with lower sulfate-to-carboxyl ratios and N-sulfate group percentages (chondroitin sulfate and dermatan sulfate) stimulate proliferation and produce a decrease of differentiative markers; on the contrary, polysaccharides with high charge density and N-sulfate group amounts (heparin and derivatives) inhibit U-937 proliferation and induce terminal differentiation. A previous paper (N. Volpi, L. Bolognani, A. Conte, and M. Petrini, (1993) Leukemia Res. 17, 789-798) demonstrates dissimilar effects on U-937 cells by chondroitin sulfates with different structures and physicochemical properties. In this study we confirm the importance of glycosaminoglycan structures and physicochemical properties in regulating cell functions. Possible mechanisms of action are discussed.

Animals↗
PubMed1994

Epidemiology of urinary stone disease in the Balearic Islands Community.

In a survey conducted on 1500 individuals, an overall prevalence of 14.3% for the year 1990 was found for urinary stone disease in the Balearic Islands. The prevalence showed higher figures for people living in rural areas than for those living in cities, and this could be correlated with traditional living habits such as traditional Balearic diet. Finally, a surprising fact is that only 54% had consulted a urologist as outpatients and the rare occasion at which the calculi were analyzed (15.1%).

Female↗
PubMed1994

Cutaneous vasculitis as the sole manifestation of disseminated gonococcal infection: case report.

One of the possible systemic complications of gonorrhoea is disseminated gonococcal infection (DGI), which is usually characterised by both skin and joint lesions. While joint involvement ranges from tenosynovitis to suppurative arthritis, cutaneous involvement features varied non-specific patterns often clinically and histologically consistent with vasculitis. We report a case of DGI in which an extensive, vesicobullous, haemorrhagic, and necrotic cutaneous vasculitis was the sole manifestation of the disease.

Adult↗
PubMed1994

Glycosaminoglycans and oxalocalcic urolithiasis.

A very simple analytical procedure with dimethylmethylene blue as photometric reagent was applied for the evaluation of glycosaminoglycan (GAG) urinary excretions and concentrations in both sexes, calcium oxalate stone formers, and a control group. The GAG concentrations varied significantly in stone formers (males and females) and in the control group; moreover, in some individual cases, a deficit of urinary GAGs was clearly detected. Apart from important inhibitory effects of GAGs on heterogenous calcium oxalate nucleation, the low urinary GAG content could be the cause of a pathological epithelium, favoring stone formation. The dimethylmethylene blue method is recommended as a quick screening procedure to determine a GAG deficit.

Calcium Oxalate↗
PubMed1994

L-propionyl carnitine protects erythrocytes and low density lipoproteins against peroxidation.

The effects of peroxidation on the erythrocytes of rats orally treated with L-propionyl carnitine for 15 days (50 mg/kg/day) were investigated. Peroxidation was produced by incubating the cells in the presence of the cytotoxic system: lactoperoxidase-hydrogen peroxide and iodide ions. Lysis of erythrocytes was evaluated by measuring the turbidity following the decrease in absorbance at 600 nm. The 50% of erythrocyte lysis of untreated animals was observed after 16 min and in about 30 min all the cells were lysed. With L-propionyl carnitine-treated rat erythrocytes the time at which 50% of lysis was observed increased to 23 min. L-propionyl carnitine also exerted its protective effect in vitro when incubated with untreated rat erythrocytes or human erythrocytes in the presence of the cytolytic system. The presence of L-propionyl carnitine in the incubation mixture markedly decreased the malonaldehyde formation. The protection was concentration-dependent. To establish if L-propionyl carnitine protects from oxygen reactive species or is able to stabilize the damaged membranes, a latent damage was produced by incubating the erythrocytes with the cytolytic system for a few minutes. The cells were then removed and suspended in buffered saline in the absence or in the presence of different L-propionyl carnitine concentrations. L-propionyl carnitine decreased the velocity of lysis of damaged erythrocytes. These data suggest that L-propionyl carnitine protects erythrocytes from oxygen reactive species and also stabilizes the damaged membrane probably by specific binding with protein and/or phospholipid domains. Low density lipoproteins (LDLs) from human blood were peroxidized by exposure to Cu2+ ions in the presence of various L-propionyl carnitine concentrations.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Effects of chondroitin sulfates with different structures on leukemia cells: U-937 cell proliferation and differentiation.

Chondroitin sulfates extracted and purified by different manufacturers were tested to evaluate their effects on proliferation and differentiation processes of U-937 cells. The different chondroitin sulfates were evaluated for purity, structure and physicochemical properties. The three chondroitin sulfates utilized did not present other contaminant glycosaminoglycans and proteins and had about the same relative molecular mass but different disaccharide patterns and charge density. Chondroitin sulfates with small amounts of disulfated disaccharides and low charge density, at 5 micrograms/ml concentration, doubled (about + 133%) cell proliferation in comparison to controls. In contrast, chondroitin sulfates with large amounts of disulfated disaccharides and high sulfate to carboxyl ratio were less effective (about + 15%) in stimulating cell proliferation at low concentration. A decrease of U-937 cell proliferation was observed in proportion to the increased amounts of chondroitin sulfate with low sulfate to carboxyl ratio. On the contrary, chondroitin sulfate with large amounts of disulfated disaccharides produced increased cell proliferation depending on concentration. Small amounts (5-10 micrograms/ml) of chondroitin sulfates with low charge density reduced the differentiative process of U-937 cells. Chondroitin sulfate with large amounts of disulfated disaccharides and high charge density seemed to be able to produce a significant decrease of differentiative processes only at very high concentrations (1000 micrograms/ml). These contrasting effects of chondroitin sulfates with different disaccharide patterns (and structure) and charge density on a leukemia cell line could help to explain the regulation of proliferative and/or differentiative processes of hemopoietic cells. This is underlined by the changes of types, physicochemical properties and structure of glycosaminoglycans induced by different extracellular factors and agents.

Antigens, CD↗
PubMed1993

Reversing of chlorambucil resistance by ethacrynic acid in a B-CLL patient.

We evaluated the reversing activity of ethacrynic acid in a B-CLL patient resistant to chlorambucil. The glutathione S-transferase (GST) activity, measured in peripheral blood lymphocytes, resulted extremely elevated. Ethacrynic acid, at pharmacological concentrations, partially reversed chlorambucil resistance and this result appeared related to the increased GST levels.

Aged↗
PubMed1993

A new case of partial trisomy 19q (q13.2-->qter) owing to an unusual maternal translocation.

A new case of trisomy 19q13.2-->qter is described in a male child which was caused by a maternal balanced translocation (13;19)(p13;q13.2). The major clinical features detected in the patient included the following: facial dysmorphism, bilateral coloboma, narrow and hypoplastic nails, cardiac malformations (Fallot's tetralogy), genitourinary and gastrointestinal anomalies, and agenesis of the corpus callosum. A comparison with other reported cases of partial trisomy 19q is presented. A hypothesis is proposed to account for the involvement of p13 regions of different acrocentrics in some cases of familial translocations involving a chromosome 19.

Chromosomes, Human, Pair 19↗
PubMed1993

Vitamin D3 administration and multidrug resistance in acute nonlymphoblastic leukemia.

This article reports preliminary results from a pilot study started in 1986 on patients with acute myeloblastic leukemia treated for several months with low-dose arabinosylcytosine and 1(OH)D3. During treatment or at the time of relapse, a monoblastic component was frequently found. A high percentage of patients were P-170-positive. In 2 patients it was possible to show that blasts, previously P-170-negative, became positive after treatment. In these 2 patients, failure of clinical response to antileukemic therapy was associated with this phenotype. The addition of the revertant drug nicardipine to the previously inactive treatment induced a partial response. Thus, previously reported in vitro observations on the differentiating activity of vitamin D3 metabolites, possible induction of multidrug chemoresistance by differentiating agents and the revertant activity of the Ca++ antagonist nicardipine appear to be confirmed in vivo in the reported patients.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1993

Zinc, copper and oxalocalcic urolithiasis.

The possible effects of Zn and Cu in oxalocalcic urolithiasis were investigated. The formation of calcium oxalate crystals in the presence of Zn and Cu demonstrated that their morphology is clearly affected by these ions. Thus, when such ions were present in a number of higher concentrations, a notable increase in the primary aggregation was clearly detected. On the other hand, Zn and Cu urinary levels were determined in groups of stone-formers and healthy people. Zinc urinary concentration was significantly lower for lithiasic than for healthy people and the copper urinary concentration was lower for lithiasic than healthy males, but both female groups had a similar copper urinary concentration. The mentioned differences disappeared when serum levels were considered. These obtained results have been comparatively evaluated with those obtained by other authors. When considering all the commented aspects, it is concluded that no important direct action of zinc and copper on oxalocalcic calculi genesis takes place.

Calcium Oxalate↗