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A de Agostini

Publications and source records attributed to A de Agostini.

15 recordsLinked to original sources
PubMed2001

Male fertility defects in mice lacking the serine protease inhibitor protease nexin-1.

Understanding infertility and sterility requires knowledge of the molecular mechanisms underlying sexual reproduction. We have found that male mice deficient for the gene encoding the protease inhibitor protease nexin-1 (PN-1) show a marked impairment in fertility from the onset of sexual maturity. Absence of PN-1 results in altered semen protein composition, which leads to inadequate semen coagulation and deficient vaginal plug formation upon copulation. Progressive morphological changes of the seminal vesicles also are observed. Consistent with these findings, abnormal PN-1 expression was found in the semen of men displaying seminal dysfunction. The data demonstrate that the level of extracellular proteolytic activity is a critical element in controlling male fertility.

Amyloid beta-Protein Precursor↗
PubMed2001

In vitro decrease of glomerular heparan sulfate by lymphocytes from idiopathic nephrotic syndrome patients.

BACKGROUND: Lymphocytes are involved in the physiopathologic mechanism of idiopathic nephrotic syndrome (INS). We have recently demonstrated that plasma from patients with INS decreases human glomerular epithelial cell (GEC) glycosaminoglycans (GAGs), particularly heparan sulfates (HS) in vitro. In this study we investigate the effect of peripheral blood lymphocytes (PBL) from INS patients on glomerular cell GAG and HS. METHODS: Human GECs were cultured with total peripheral blood mononuclear cells (PBMCs), PBL, and monocytes from patients and controls. The amounts of GAG and HS were assessed using a cationic membrane after metabolic labeling. RESULTS: In coculture with GECs, mononuclear cells from controls decreased total epithelial cell GAG (-30% with PBMC, P < 0.05; -25% with PBL, P < 0.02; -19% with monocytes, P < 0.05). Particularly HSs were decreased (-36% with PBMC, P < 0.05; -27% with PBL, P < 0.02; and -19% with monocytes, P < 0.05). When GECs were in coculture with PBL from INS patients, the decrease in GAG and HS was significantly greater in comparison to control PBL (-10%, P < 0.02; -10%, P < 0.02, respectively, for GAG and HS). Moreover, supernatants of stimulated PBMCs from patients decreased also GAG and HS in comparison with controls (-13%, P < 0.02; -15%, P < 0.02, respectively, for GAG and HS). CONCLUSION: These data provide direct evidence that PBLs from INS patients are able to decrease GEC HS as previously shown with plasma from patients. This might be instrumental in the onset of albuminuria.

Cells, Cultured↗
PubMed1996

Quantitative post-coital test: sperm counts in cervical mucus after enzymatic liquefaction.

The post-coital test involves direct microscopic examination of sperm number and motility in cervical mucus. The results depend on the quality of the mucus and the distribution of spermatozoa within the sample. To progress from such qualitative data to quantitative measurements of the spermatozoa present in post-coital mucus, we have developed methods to measure sperm concentrations in enzymatically liquefied post-coital cervical mucus. The mucus score and sperm motility were measured prior to mucus liquefaction, and, together with sperm concentration, they allowed the calculation of the total number of motile spermatozoa present. A combination of bromelin and glycosidases proved to be more efficient in achieving reliable mucus liquefaction than treatment with bromelin alone, and was used to liquefy a series of 36 post-coital test samples. Total sperm numbers ranged between 19 x 10(3) and 16.8 x 10(6). Of the samples, 75% contained < 3 x 10(6) spermatozoa, and 39% contained < 1 x 10(6) spermatozoa. Sperm motility was very high in these samples, except for a distinct subset of samples (19%) in which the total sperm motility was markedly decreased ( < 20%). The measurement of sperm concentration in liquefied cervical mucus will help to determine normal values for the post-coital test, and to estimate the number of motile spermatozoa reaching the upper female genital tract.

Bromelains↗
PubMed1996

Sperm counts in enzymatically liquefied cervical mucus: quantitative validation using donor cervical mucus.

The post-coital test evaluates the penetration of spermatozoa into cervical mucus; it relies on subjective measurements and therefore lacks precision. Enzymatic liquefaction of cervical mucus allows sperm concentration to be measured in post-coital test samples, but the reliability of such measurements is not known. Donor cervical mucus was used as a model to test the accuracy and sensitivity of sperm quantification in liquefied cervical mucus. Donor cervical mucus was dissolved by enzymatic treatments in the presence of known numbers of spermatozoa and the recovery of sperm cells was assessed after liquefaction of the samples. Enzymatic treatment of cervical mucus with a combination of bromelin and glycosidases resulted in reliable and fast liquefaction of the samples. The accuracy of sperm concentration measurements was 89 +/- 10% (mean +/- SD, n = 50), and the sensitivity limits were 1 x 10(6) and 0.2 x 10(6) spermatozoa/ml for quantitative concentration measurement and qualitative sperm detection respectively. This study demonstrates that liquefaction of cervical mucus by combined protease and glycosidases allows accurate and sensitive determination of sperm concentration in the sample. Therefore we believe that valuable data can be obtained for sperm concentration and total sperm counts in post-coital tests, that should help to improve the reliability of the post-coital test.

Cervix Mucus↗
PubMed1995

Evaluation of infertility.

The most important goal of fertility investigation is to identify the cause(s) of infertility and to prescribe adequate therapy. The couple should be treated as a single unit as each partner contributes a share to the infertility potential of the couple. Evaluation should begin with the taking of a detailed history and a complete physical examination of both partners, which may point the investigation in a particular direction. However, other pertinent fertility factors should not be overlooked. A standardized and comprehensive approach to the investigation of infertility is proposed and is presented as a series of flow charts.

Algorithms↗
PubMed1988

A common neoepitope is created when the reactive center of C1-inhibitor is cleaved by plasma kallikrein, activated factor XII fragment, C1 esterase, or neutrophil elastase.

The reactive center of C1-inhibitor, a plasma protease inhibitor that belongs to the serpin superfamily, is located on a peptide loop which is highly susceptible to proteolytic cleavage. With plasma kallikrein, C1s and beta-Factor XIIa, this cleavage occurs at the reactive site residue P1 (Arg444); with neutrophil elastase, it takes place near P1, probably at residue P3 (Val442). After these cleavages, C1-inhibitor is inactivated and its conformation is modified. Moreover, in vivo, cleaved C1-inhibitor is removed from the blood stream more rapidly than the intact serpin, which suggests that proteolysis unmasks sites responsible for cellular recognition and the uptake of the cleaved inhibitor. In the study reported here, we show, using an MAb, that an identical neoepitope is created on C1-inhibitor after the cleavage of its exposed loop by plasma kallikrein, C1s, beta-Factor XIIa, and by neutrophil elastase.

Animals↗
PubMed1985

Human plasma kallikrein and C1 inhibitor form a complex possessing an epitope that is not detectable on the parent molecules: demonstration using a monoclonal antibody.

The inactivation of human plasma kallikrein (EC 3.4.21.8) by the inhibitor of activated complement component 1 (C1 inhibitor) induces the formation of a 1:1 stoichiometric kallikrein-C1 inhibitor complex and a proteolytically modified form of C1 inhibitor. We have produced a monoclonal antibody that recognizes the kallikrein-C1 inhibitor complex as well as modified C1 inhibitor but fails to react with virgin C1 inhibitor or native plasma kallikrein. This observation constitutes an unequivocal demonstration that the reaction between plasma kallikrein and C1 inhibitor leads to the emergence of an epitope that is undetectable on the parent enzyme and inhibitor molecules.

Antibodies, Monoclonal↗
PubMed1985

Effect of cleavage of the heavy chain of human plasma kallikrein on its functional properties.

Human plasma kallikrein consists of an N-terminal heavy chain of molecular weight (mol wt) 52,000, linked by disulfide bonds to two light chain variants (mol wt 36,000 or 33,000). Although the active catalytic site of kallikrein resides on the C-terminal light chain, the role of the N-terminal heavy chain is less clear. We therefore studied an enzyme designated beta-kallikrein, containing a single cleavage in the heavy chain (mol wt 28,000 + 18,000) and compared it to the enzyme, alpha-kallikrein, with an intact heavy chain. The rates of inactivation by C1 inhibitor of plasma alpha- and beta-kallikreins were kinetically identical, as measured by residual amidolytic activity, after various times of incubation with the inhibitor. Both enzymes reacted completely with C1 inhibitor after 18 hours and formed identical C1 inhibitor-kallikrein complexes of mol wt 195,000. The rate of activation of factor XII by alpha-kallikrein and beta-kallikrein was similar. In contrast, the rate of cleavage of high molecular weight kininogen (HMWK) by alpha-kallikrein was at least fivefold faster and the ratio of coagulant activity to amidolytic activity was fourfold greater than for beta-kallikrein. Plasma alpha-kallikrein, at concentrations potentially achievable in plasma, induced aggregation of neutrophils, but beta-kallikrein failed to elicit this response. In addition, human neutrophils pretreated with cytochalasin B released 2.46 +/- 0.10 microgram/10(7) cells of elastase antigen, but beta-kallikrein released only 0.25 +/- 0.10 micrograms/10(7) cells. These observations suggest that cleavage of the heavy chain influences the rate of cleavage of HMWK and decreases its coagulant activity. Moreover, an intact heavy chain appears to be requisite to support the ability of kallikrein to aggregate neutrophils and release elastase.

Blood Coagulation Tests↗
PubMed1984

[Role of bradykinin in hypotension induced by the active factor derived from factor XII].

The active fragment derived from factor XII (factor XIIf) was purified from human plasma and administered intravenously to normotensive conscious rats. Factor XIIf-mediated hypotension was dose-dependent and augmented by pretreatment with captopril, an inhibitor of the angiotensin I- and bradykinin-processing enzyme. In contrast, factor XIIf-induced hypotension was not enhanced by blockade of the renin-angiotensin system by saralasin, a competitive antagonist of angiotensin II at the vascular receptor level. These results suggest that factor XIIf-mediated hypotension is due to the formation of bradykinin.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1984

Inactivation of factor XII active fragment in normal plasma. Predominant role of C-1-inhibitor.

To define the factors responsible for the inactivation of the active fragment derived from Factor XII (Factor XIIf ) in plasma, we studied the inactivation kinetics of Factor XIIf in various purified and plasma mixtures. We also analyzed the formation of 125I-Factor XIIf -inhibitor complexes by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). In purified systems, the bimolecular rate constants for the reactions of Factor XIIf with C-1-inhibitor, alpha 2-antiplasmin, and antithrombin III were 18.5, 0.91, and 0.32 X 10(4) M-1 min-1, respectively. Furthermore, SDS-PAGE analysis revealed that 1:1 stoichiometric complexes were formed between 125I-Factor XIIf and each of these three inhibitors. In contrast, kinetic and SDS-PAGE studies indicated that Factor XIIf did not react with alpha 1-antitrypsin or alpha 2-macroglobulin. The inactivation rate constant of Factor XIIf by prekallikrein-deficient plasma was 14.4 X 10(-2) min-1, a value that was essentially identical to the value predicted from the studies in purified systems (15.5 X 10(-2) min-1). This constant was reduced to 1.8 X 10(-2) min-1 when Factor XIIf was inactivated by prekallikrein-deficient plasma that had been immunodepleted (less than 5%) of C-1-inhibitor. In addition, after inactivation in normal plasma, 74% of the active 125I-Factor XIIf was found to form a complex with C-1-inhibitor, whereas 26% of the enzyme formed complexes with alpha 2-antiplasmin and antithrombin III. Furthermore, 42% of the labeled enzyme was still complexed with C-1-inhibitor when 125I-Factor XII was inactivated in hereditary angioedema plasma that contained 32% of functional C-1-inhibitor. This study quantitatively demonstrates the dominant role of C-1-inhibitor in the inactivation of Factor XIIf in the plasma milieu.

Antithrombin III↗
PubMed1984

Hypotensive effect of human factor XII active fragment in conscious normotensive rats: role of bradykinin.

The active fragment derived from factor XII (factor XIIf) was purified from human plasma and administered intravenously to normotensive conscious rats. Factor XIIf-mediated hypotension was dose-dependent and augmented by pretreatment with captopril, an inhibitor of the bradykinin-processing enzyme kininase II. These results therefore suggest that factor XIIf-mediated hypotension is due to the formation of bradykinin.

Animals↗
PubMed1982

Renin-like and cathepsin D activities in bovine pineal glands.

Pineal extract is shown to contain both renin-like and cathepsin D activities. Evidence of renin-like activity in the bovine pineal gland was brought by incubation with natural and synthetic renin substrates and by inhibition by pepstatin. Cathepsin D activity was demonstrated by incubation with hemoglobin and synthetic fluorogenic peptide. The separation of both activities was performed by affinity chromatography on a caseinyl-Sepharose gel. The elution of the extract on affinity chromatography allowed to separate the renin-like activity, which is not retained by the gel at acid pH, from cathepsin D activity, which binds to the column at acid pH and is eluted at alkaline pH. The isolated pineal renin-like activity was found higher on tetradecapeptide renin substrate than on angiotensinogen at pH 5.5. The pH dependence of pineal renin-like activity showed two peaks of activity. One broad peak between pH 6 and 8 and one sharp peak at pH 3.5-4. These results demonstrate the existence of renin-like and cathepsin D activities in bovine pineal gland. They suggest moreover that the renin-like activity measured might represent a mixture of at least two different enzymatic activities.

Angiotensinogen↗
PubMedDate not supplied

Evaluation of 'round cells' in semen analysis: a comparative study.

The aims of this review are to evaluate the morphological differences between 'round cells' of spermatogenic and non-spermatogenic origin in semen. The latter group includes inflammatory cells like neutrophils, lymphocytes, and macrophages, and epithelial cells. A comparison was made between non-spermatogenic cells in semen samples and inflammatory cells in blood smears, using various staining procedures commonly used in routine andrology laboratories. The result presented in this review confirmed previously published data. In blood smears as well as in semen samples, only neutrophil leukocytes (both eosinophilic and basophilic) showed a positive reaction when exposed to the peroxidase stain. Lymphocytes, macrophages and other 'round cells' such as epithelial cells and spermatogenesis cells remained negative. It could be concluded that the neutrophil polymorphonuclear leukocytes were the only 'round cells' showing a positive reaction in the semen samples. The presence of specifically stained neutrophils in semen was considered to be compatible with an infection and/or a subsequent inflammatory reaction in the male genital tract. The potential influence of inflammatory cells in the sperm samples on infertility/subfertility is discussed. However, the question of determining if morphologically abnormal, degenerated spermatids are still capable of fertilizing an oocyte in vitro is not addressed in this review.

Animals↗