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Biomedical subjects

M Conti

Publications and source records attributed to M Conti.

At least 271 records · Page 15Linked to original sources
PubMed1988

Sleep apnoea syndrome in pregnancy: a case report.

A case of sleep apnoea syndrome in a pregnant patient is reported here. For obstetric reasons, and because of the possibility that a metabolic and respiratory acidosis associated with the apnoea syndrome might have developed, we decided to do a caesarian section. Orotracheal intubation was particularly difficult because of the patient's abnormal mandibular, palatal and retropharyngeal shape, which was probably the underlying cause of the apnoeic syndrome.

Adult↗
PubMed1988

Antiulcer activity of an anthocyanidin from Vaccinium myrtillus.

The antiulcer effects of 3,5,7-trihydroxy-2-(3,4-dihydroxyphenyl)-1-benzopyrylium chloride (IdB 1027) were assessed in various experimental models. Given orally, IdB 1027 antagonized gastric ulcerations induced by pylorus ligation, stress, nonsteroidal antiinflammatory drugs, ethanol, reserpine, histamine and duodenal ulceration induced by mercaptamine (cysteamine). Moreover it antagonized chronic gastric ulcers induced by acetic acid. Given intraperitoneally, it was more potent than after oral administration. IdB 1027 did not affect gastric secretion in pylorus-ligated rats and increased gastric mucus in normal animals both in the absence and in the presence of indometacin treatment. Tolerability was very good. These results indicate that IdB 1027 possesses a promising antiulcer activity, probably by potentiating the defensive barriers of the gastrointestinal mucosa.

Animals↗
PubMed1987

Inhibition by phorbol esters and other tumor promoters of the response of the Sertoli cell to FSH: evidence for dual site of action.

Several tumor promoters exert their effects by activating a Ca2+-phospholipid-dependent protein kinase (protein kinase C). To study the role of this protein kinase in the regulation of Sertoli cell function, we have evaluated the effect of phorbol esters, mezerein, and teleocidin on the response of the Sertoli cell to FSH. Cells were treated for different time intervals with the tumor promoters, and cell response was measured by stimulating the cell with FSH. 12-O-Tetradecanoylphorbol 13-acetate (TPA) had no significant effect on basal cAMP production but markedly inhibited the cAMP response to FSH. Significant inhibition of cAMP accumulation was observed after 15 min treatment with 100 nM TPA, and maximal inhibition developed within 1 h. The decrease in cAMP accumulation was dependent on the dose of phorbol ester used, with an estimated ED50 of 10-20 nM TPA. In a manner similar to TPA, mezerein and teleocidin also inhibited the cAMP response of the Sertoli cell, while the phorbol ester 4 alpha-phorbol 12,13-didecanoate (4 alpha-PDD), inactive as a tumor promoter and unable to stimulate protein kinase C activity, was devoid of effect. The promoters that inhibited cAMP response also inhibited the FSH-stimulated androgen aromatization. The dose of TPA producing half-maximal inhibition of estrogen accumulation was again 10-20 nM TPA, mezerein, and teleocidin inhibited estrogen accumulation whether FSH, forskolin or cholera toxin was used to stimulate the Sertoli cell. In contrast, only FSH-dependent cAMP accumulation was inhibited by the tumor promoters, while forskolin and cholera toxin stimulations were not affected. These data suggest that tumor promoters which activate protein kinase C act at two sites of the Sertoli cell response. They alter receptor-mediated signal transduction across the membrane and affect steroidogenesis at a site distal to cAMP accumulation.

Androstenedione↗
PubMed1987

The role of benzydamine in the topical treatment of the so-called non-specific vaginitis.

The authors report the preliminary results of their investigation of the efficacy of benzydamine in the treatment of the so-called non-specific vaginitis. An initial in vitro study to test its bacteriostatic and/or bactericidal activity on Gardnerella vaginalis showed that the drug has high activity even at the lowest concentrations, and completely inhibits this micro-organism at 1000 micrograms/ml which is the usual concentration employed in therapy. The first pilot study performed in vivo on 14 selected vaginitis cases which were found positive for G. vaginalis by culture test appears to confirm the therapeutic efficacy of benzydamine; however, this confirmation must await the results of a double-blind clinical trial which is still in progress.

Administration, Intravaginal↗
PubMed1986

Putative second messengers affect cell coupling in the seminiferous tubules.

Junctional transfer of ions in monolayer primary cultures of Sertoli cells and in intact seminiferous tubules from 20 day-old rats has been investigated by using electrophysiological techniques. The electrotonic coupling of both intact tubule and monolayer culture was inhibited by the presence of dibutyryl cyclic AMP (10(-4) M) in the medium. In contrast, 1-oleoyl-2-acetylglycerol (10(-5) M) and 12-O-tetradecanoyl-phorbol-13-acetate (10(-7) M) decreased the junctional resistivity and increased the extent of the coupling in immature tubules. The significance of this modulation of the cell coupling in the seminiferous epithelium is discussed.

Animals↗
PubMed1986

Localization of adenosine receptors in rat testicular cells.

The localization of adenosine receptors in rat testicular cells was investigated by evaluating the binding of cyclohexyladenosine (CHA) to somatic and germ cells and by assessing the effect of purine nucleosides on the function of testicular cells. Most of the specific binding of CHA in the testicular homogenate was found in the seminiferous tubule fraction, with little specific binding present in the interstitial compartment. Specific binding was also detected in a total-cell suspension prepared by dispersion of the seminiferous tubules. However, the specific activity of the binding did not increase when such a suspension was fractionated to produce germ cells at different stages of spermatogenesis. Adenosine receptors were present in the crude particulate fraction prepared from testes of rats from 10 to 90 days of age. While the affinity of these receptors did not vary as the testis matured, the number of binding sites per testis increased markedly up to 60 days after birth. Conversely, when binding activity was expressed per mg of testicular protein, no major changes in the specific activity of the binding were detected in testes up to 90 days of age. Sertoli cell-enriched cultures possessed a large number of binding sites, with a receptor density of 722 +/- 147 fmoles bound/mg protein (mean +/- SE; n = 5) and an affinity constant (Kd) of 1-2 nM. Among the characteristics of this binding site were kinetics constants and specificity similar to those measured in total particulate fractions of the testis and in the brain. Specific binding of CHA was not detected in cultures of testicular peritubular cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine↗
PubMed1986

Serological relationships between the nucleocapsids of some planthopper-borne rhabdoviruses of cereals.

Leaves infected with barley yellow striate mosaic virus (BYSMV) from Italy, wheat chlorotic streak virus (WCSV) from France, northern cereal mosaic virus (NCMV) from Japan, maize sterile stunt virus (MSSV) from Australia or Shiraz maize rhabdovirus (SMRV) from Iran were homogenized in buffered 1% Nonidet P-40, releasing intact nucleocapsids. These (except SMRV) were trapped on electron microscope grids using appropriate antisera and tested by decoration with serial dilutions of antisera to BYSMV, NCMV, MSSV, Moroccan wheat rhabdovirus (MWRV), wheat rosette stunt virus (WRSV) from China, and maize mosaic virus (MMV) from Venezuela. The results suggest that BYSMV and NCMV, though related, are distinct viruses; MWRV and WCSV are strains of BYSMV; MSSV is intermediate between BYSMV and NCMV but may be considered a strain of BYSMV; WRSV is a strain of NCMV; and MMV and SMRV are unrelated to each other and to the other viruses tested. SMRV was morphologically quite different from BYSMV, NCMV, WCSV and MSSV, all of which had the same morphology.

Animals↗
PubMed1986

Effect of phosphodiesterase inhibitors on Sertoli cell refractoriness: reversal of the impaired androgen aromatization.

Responsiveness of the Sertoli cell after FSH pretreatment was evaluated in terms of androgen aromatization. Sertoli cell cultures were preincubated with FSH for 24 h, then cells were washed free of hormone and reincubated with FSH in the presence of androstendione. The estrogen accumulated in the medium was measured by RIA. Gonadotropin pretreatment produced a marked refractory state, and a second challenge with FSH did not produce an increase in androgen aromatization. A dose-response study showed that FSH pretreatment produced three separate effects on Sertoli cell steroidogenesis: an increased basal production of estrogen; a decreased maximal response when doses of 10 ng/ml FSH or higher were employed in the preincubation; and a decreased sensitivity of the Sertoli cell to FSH. In the last case, the ED50 was reduced approximately 3- to 5-fold. Such an impaired stimulation of androgen aromatization was no longer present when cells were incubated with the phosphodiesterase inhibitors methyl-isobutyl-xanthine (MIX). In the presence of this inhibitor, refractory cells responded to FSH better than the control cells. The possibility that MIX stimulated cAMP accumulation by acting as antagonist of purine receptor was ruled out by the finding that the nonxanthine phosphodiesterase inhibitor 4-(3-butoxy-4-methoxybenzyl)2-imidazolidinone (Ro 20-1724) also reverted the refractory state. Pretreatment of the Sertoli cells with FSH produced an impaired response in the second incubation also to isoproterenol, cholera toxin, and forskolin. The response to these compounds was apparently normal when cells were incubated in the presence of MIX or Ro 20-1724. Conversely, refractory cells responded to (Bu)2cAMP in a manner indistinguishable from the fully responsive control cells. These data demonstrate that FSH induces homologous and heterologous refractory states of the Sertoli cell reflected by an impaired estrogen production. The finding that phosphodiesterase inhibitors fully restore the FSH response suggests an important role of phosphodiesterase in the induction and/or maintenance of such refractoriness.

1-Methyl-3-isobutylxanthine↗
PubMed1986

Pregnancy in women with different types of von Willebrand disease.

The course and outcome of pregnancy in women with different types of von Willebrand disease (3 type I, 1 subtype IIA, and 1 subtype IIB) are described. In all patients, factor VIII increased and reached normal levels before delivery, whereas the bleeding time remained prolonged; in subtypes IIA and IIB the abnormal multimeric structure of von Willebrand factor remained unchanged. Deliveries were uneventful in all patients, with two spontaneous vaginal deliveries and three cesarean sections, despite the fact that no replacement therapy was given. Hence, the most important determinant of abnormal hemorrhage during delivery is low factor VIII; the prolonged bleeding time can be compensated for by meticulous surgical hemostasis and efficient contraction of the uterus. Replacement therapy with plasma derivatives can usually be avoided providing that normal factor VIII levels have been attained at delivery.

Adult↗
PubMed1985

Interindividual differences in the binding of antidepressives to plasma proteins: the role of the variants of alpha 1-acid glycoprotein.

Alpha 1-acid glycoprotein (AAG) is one of the plasma proteins that bind basic drugs, like amitriptyline (AT) and its metabolite nortriptyline (NT). Two types of genetic polymorphism have been described for AAG: polymorphic forms which, on electrophoresis of the native protein, give four patterns with 5, 6, 7 or 8 bands, and the variants which on by electrophoresis of the desialysed protein, give three patterns with 2 bands, FF, FS and SS. In 31 depressive patients, treated daily with 150 mg AT for 3 weeks, free and total plasma AT and NT were determined, as well as the AAG polymorphic forms and variants. There was only a weak negative correlation between the free fractions of AT and NT and total plasma AAG, but free AT and NT were strongly correlated with the S form (but not the F form) of AAG variants. The differences in binding might be the expression of a further genetic factor determining the steady-state plasma levels of tricyclic drugs.

Adult↗
PubMed1985

Cell-to-cell communication in cultured Sertoli cells.

Junctional transfer of ions in monolayer primary cultures of Sertoli cells has been studied by using conventional techniques. Cells were extensively electrically coupled. Membrane voltage displacements caused by the injected current pulses were measured at variable interelectrode distance. Data analyses were based on a thin-sheet model for current flow (Jongsma and van Rijn, 1972) and yielded a generalized space constant of 248 microns and an internal resistivity of 1.7 kOhm.cm in standard medium. Electrical coupling was inhibited by A23187 Ca2+ ionophore (5 microM).

Animals↗
PubMed1985

Effect of follicle-stimulating hormone on cyclic adenosine monophosphate level and on meiotic maturation in mouse cumulus cell-enclosed oocytes cultured in vitro.

We have reported that in vitro treatment with follicle-stimulating hormone (FSH) delays by about 3 h spontaneous meiotic resumption in cumulus cell-enclosed mouse oocytes. In the present paper we show that the temporary meiotic block is accompanied by a transient increase of cAMP concentration in the oocyte. In cumulus cell-oocyte complexes stimulated with 1 microgram/ml FSH, cAMP significantly increases within 1 h both in the whole complex (from a basal value of 1.9 +/- 0.2 to 169 +/- 13 fmol) and in the enclosed oocyte (from 0.9 +/- 0.2 to 2.4 +/- 0.2 fmol), then progressively decreases to basal values. Stimulation by FSH does not cause any cAMP increase in denuded oocytes. As the concentration of cAMP in the cells decreases, the percentage of oocytes escaping the meiotic block imposed by FSH increases. If the complexes are cultured in the presence of 1 microgram/ml FSH plus 1 mM isobutyl-1-methylxanthine (1BMX), cAMP concentration increases approximately 250-fold in the complex, and 10-fold in the enclosed oocyte; the level of cAMP in the oocyte drops very rapidly (50% degradation in less than 2 min) if the oocyte is then transferred to IBMX-free medium. The data are discussed in terms of the possible role of cAMP transfer from cumulus cells to the oocyte in the regulation of meiotic progression in mouse oocytes.

1-Methyl-3-isobutylxanthine↗
PubMed1985

Cyclic nucleotide phosphodiesterases in somatic and germ cells of mouse seminiferous tubules.

The distribution of phosphodiesterase forms in somatic and germ cells, and their variations during testicular development and germ cell differentiation have been investigated. Seminiferous tubules from immature mice and Sertoli cells in culture possessed two enzyme activities which were comparable to forms described for different tissues and species: (a) a calcium-calmodulin-dependent enzyme with high affinity for guanosine 3',5'-(cyclic)-monophosphate (cGMP), and (b) a calcium-calmodulin-independent enzyme with high affinity for adenosine 3',5'-(cyclic)-monophosphate (cAMP) the activity of which increased in cultured Sertoli cells after treatment with FSH or dibutyryl cAMP. Seminiferous tubules from adult animals and germ cells at the meiotic and post-meiotic stage of differentiation possessed two enzyme forms that could be distinguished from those present in somatic cells of the seminiferous tubules: (a) a calcium-calmodulin-dependent form with high affinity for both cAMP and cGMP, similar to forms described in other tissues from different species, and (b) a calcium-calmodulin-independent phosphodiesterase with high affinity for cAMP and present only in post-meiotic cells, previously identified also in germ cells of the rat.

2',3'-Cyclic-Nucleotide Phosphodiesterases↗