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Biomedical subjects

D Rodrigues

Publications and source records attributed to D Rodrigues.

At least 37 records · Page 2Linked to original sources
PubMed1995

High levels of sperm-associated antibodies impair human spermoolemma interaction after subzonal insemination.

OBJECTIVE: To investigate the impact of sperm-associated antibodies in the fertilization process beyond the zona pellucida in human oocytes. DESIGN: Subzonal insemination (SUZI) was performed with antibody-coated spermatozoa from patients with autoimmune infertility. Sperm parameters and antibody binding were analyzed after Percoll selection and were compared with SUZI outcome. PATIENTS: Patients (n = 29) with an immunobead test higher than 60% for immunoglobulin (Ig)G, IgA, or both classes were included in the study (38 attempts). Twenty-six patients had previous IVF failures, and the semen characteristics for three were unsuitable for IVF. RESULTS: Diploid fertilization occurred in 52.6% of cycles and 16.0% of oocytes (n = 263). The fertilization rate was inversely correlated to the proportion of spermatozoa coated with IgG in the Percoll-selected sperm suspension. Three of the 16 attempts in which > 90% of the spermatozoa were coated with IgG resulted in a low diploid rate of 4.1%. Fertilization was obtained in 18 of the 22 attempts in which < 90% of spermatozoa were IgG coated, with a diploid fertilization rate of 22.8%. Association of both classes of antibodies (IgG and IgA) further impaired the fertilization rate. Twenty ETs gave four pregnancies: one biochemical, one ongoing, and two giving birth to healty babies (1 singleton and 2 twins). CONCLUSIONS: Subzonal insemination is a potential solution for achieving fertilization in cases of IVF failure because of sperm autoimmunity. However, IgG inhibits in a dose-dependent manner the fusion of gametes' membranes. Though the level of IgA antibodies does not appear as critical as that of IgG antibodies, association of both classes of Igs impairs the probability of fertilization.

Adult↗
PubMed1995

Human oocyte cytometry and fertilisation rate after subzonal insemination.

The cytometry of 545 oocytes was evaluated during subzonal insemination (SUZI; 85 attempts), on day 0 (egg retrieval and SUZI), day 1 and day 2 (embryo transfer). On day 0, the egg and oolemma diameters (mean +/- SD) were 164.0 +/- 19.6 microns and 114.2 +/- 16.8 mu 5m respectively. The zona thickness was 17.8 +/- 13.4 microns and correlated with the oolemma diameter (r = 0.24, p < 0.001). The fertilisation rate was significantly lower for the smaller oocytes (less than 108 microns diameter) compared with the larger oocytes (over 108 microns) (9.8% vs 21.2% respectively; p < 0.05). There was little variation in oocyte diameter according to nuclear status. However, oocyte diameter increased significantly between day 0 and day 1 (p < 0.001) for both fertilised and unfertilised oocytes. Six different indications for SUZI were investigated in detail: three with non-specific (normal and subnormal sperm with in vitro fertilization failure, oligoasthenospermia) and three with specific sperm defects (flagellar dyskinesia, absence of outer dynein arms, antisperm antibodies). Oocytes from the non-specific defect groups had significantly smaller diameters than the others (p < 0.05). The mean fertilisation rate was related to the mean oolemma diameter for the groups with non-specific sperm defects and the group lacking dynein arms (LODA) (r = 0.91, p < 0.05). Eggs from the groups of patients with LODA and those with antisperm antibodies had thicker zona pellucida than others (p < 0.05). These findings suggest that in addition to nuclear criteria of maturity, the growth of oocytes is an important factor for fertilising ability.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Influence of sperm movement parameters on human sperm-oolemma fusion.

Flagellar dyskinesia is characterized by abnormal sperm movement parameters and a negative sperm mucus penetration test. It is associated with structural pathologies of the axonemal complex (lack of outer dynein arms), of the periaxonemal complex (sliding spermatozoa and periaxonemal dyskinesia), or of both structures (short flagella). Even during in vitro fertilization, dyskinesia prevents the spermatozoon from getting through the egg vestment. However, in some cases, fertilization has been achieved using subzonal insemination. Flagellar dyskinesia is therefore an interesting model for investigating the role of sperm movement in the fusion process between the spermatozoon and the oolemma. Thirty-one patients requiring assisted fertilization were included in the study. Fifteen had spermatozoa in which the flagellum lacked outer dynein arms, 11 had anomalies of the periaxonemal complex (five with sliding spermatozoa and six with periaxonemal dyskinesia) and five had spermatozoa with short flagella. Seven men who produced spermatozoa with normal movement were selected as controls. Movement was evaluated using a computer-assisted analyser, and penetration was assessed using zona-free hamster eggs. At 37 degrees C, in semen, the dyskinetic spermatozoa had reduced straight line and curvilinear velocity and lateral head displacement compared with controls (P < 0.01). In the Percoll-selected sperm suspension, the only difference was that spermatozoa with periaxonemal anomalies maintained a narrow lateral head displacement compared with the controls (P < 0.001). After 3 h of incubation at 37 degrees C, the lateral head displacement of dyskinetic spermatozoa had not changed, while that of the controls showed a significant increase (4.5 to 5.6 microns; P < 0.05). The results from the sperm penetration assay for the spermatozoa lacking outer dynein arms were lower than those of the controls (47% versus 77%; P < 0.05) and the results for sliding spermatozoa and spermatozoa with periaxonemal dyskinesia were even lower (25% and 34%, respectively; P < 0.01). The fertilization rates after subzonal insemination were 46.5% for spermatozoa lacking outer dynein arms, 36.1% for spermatozoa with short flagella, 24.8% for sliding spermatozoa and 17.3% for spermatozoa with periaxonemal dyskinesia. There was a significant correlation between the curvilinear velocity of the Percoll-selected sperm suspensions and their fertilization rates after subzonal insemination (r = 0.5; P < 0.05) and their sperm penetration assays (r = 0.7; P < 0.001). The data provide evidence that sperm velocity is correlated with the ability to fuse with the oolemma.

Animals↗
PubMed1993

Cytogenetic analysis of human oocytes after subzonal insemination.

Subzonal insemination has been proposed to achieve fertilization in cases where standard in vitro fertilization has failed. We present the results of chromosome analysis of oocytes after subzonal insemination. Our data suggest that the main cause (76 per cent) of the absence of cleavage after subzonal insemination is the total absence of sperm nucleus evolution of the injected spermatozoa. Our results also suggest that spermatozoa chromatin development is normal after subzonal insemination. Aneuploidy does not seem to be increased in zygotes after subzonal insemination. However, polyploidy was often more important than predicted by the observation of pronuclei (PN). Pronucleus development might be asynchronous and can appear earlier or later than after standard IVF. The cytogenetic risk after subzonal insemination might therefore be triploidy (if a triploid egg is transferred, because only 2 PN were seen) rather than aneuploidy or structural abnormalities.

Cell Nucleus↗
PubMed1993

Localization of antibodies on spermatozoa and sperm movement characteristics are good predictors of in vitro fertilization success in cases of male autoimmune infertility.

OBJECTIVE: To define sperm factors related to in vitro fertilization (IVF) failure in cases of antisperm autoimmunity. DESIGN: A detailed analysis of sperm morphology, movement characteristics, acrosomal function, and antibody binding was performed on the sperm population selected on a discontinuous two-layer Percoll gradient and used for IVF. The results were compared retrospectively between fertilizing (n = 13) and nonfertilizing (n = 11) sperm populations. PATIENTS: Twenty-one infertile couples undergoing 24 cycles of IVF treatment because of antisperm autoimmunity were included in this study. RESULTS: Fertilizing and nonfertilizing sperm populations were not different with respect to the percentage of motility, the normal morphology, the multiple anomalies index, the acrosome abnormalities, and the spontaneous or induced acrosome reaction. If the proportion of spermatozoa coated with either immunoglobulin (Ig)A or IgG antibodies was similar in the two groups, their localization was often different: antibodies were mainly on the sperm heads in the cases of fertilization failure. There were significant differences between fertilizing and nonfertilizing sperm samples in several movement parameters. Among them, the amplitude of lateral head displacement (ALH) was the most significantly correlated with fertilization success. Finally, spermatozoa were poorly bound to the zona pellucida (ZP) when fertilization failed, whereas high numbers of spermatozoa were attached to the ZP when fertilization occurred. CONCLUSION: Fertilization failure in patients with antisperm antibodies may be the result of several factors in which the impact of the antibodies on the membrane function play a critical role. Movement parameters, particularly the ALH and the localization of antibodies on migrated spermatozoa could predict the IVF failure or success more accurately than the proportion of antibody-coated spermatozoa in the inseminated populations. The fertilization failure was associated with an incapacity of spermatozoa to bind to ZP.

Acrosome↗
PubMed1993

Variability of cardiovascular and plasma noradrenaline responses to sustained isometric contraction in normal human subjects.

1. Eight healthy adult males underwent three sustained isometric contractions at 30% of maximal voluntary contraction for 3 min, within a 9 day period. 2. The study focuses on the inter-individual and day-to-day intra-individual variability of cardiovascular and plasma noradrenaline responses to sustained isometric contraction. 3. The results of this study indicate that inter-individual variability is generally greater than intra-individual variability. Diastolic blood pressure was the most sensitive as well as the least variable cardiovascular parameter measured. 4. The variability of plasma noradrenaline levels in both the basal and the stimulated state was high. The present study suggests that it is preferable to determine the 'true' noradrenaline peak after the release of handgrip, as this is associated with a lower variability than the plasma noradrenaline peak taken at the time of the release of handgrip.

Adult↗
PubMed1993

Pregnancy after subzonal insemination with spermatozoa lacking outer dynein arms.

The absence of outer dynein arms in the sperm flagellum induces an abnormal movement pattern associated with male infertility. These spermatozoa can decondense in zona-free hamster oocytes but result in a very low fertilization rate in in vitro fertilization. We hypothesized that subzonal insemination could help achieve fertilization and pregnancy. A randomized prospective trial (five couples, five cycles) comparing subzonal insemination (n = 31 oocytes) and routine IVF (n = 23 oocytes) was carried out. Oocytes were microinjected with 8.5 +/- 3.6 spermatozoa. In a second series (nine cycles), all the oocytes were microinjected with 10.5 +/- 4.3 spermatozoa. In the randomized series, the fertilization rate was 16.1% without polyploidy, whereas no fertilization was obtained after control IVF insemination. In the second series involving nine couples, six of whom were included in the first series, the fertilization rate increased to 57.8% with a 27.8% polyspermic rate. Eighty-eight per cent of the zygotes cleaved normally (29 out of 33). A total of 11 embryo transfers resulted in three pregnancies, one of which terminated one month later, a second being ongoing and the third delivering a healthy girl. A 21.4% pregnancy rate per cycle, with a 37.5% pregnancy rate per couple, justifies the use of subzonal insemination to treat this particular flagellar dyskinesia.

Adult↗
PubMed1993

Immediate heart rate responses to head-up tilt in healthy human subjects: response characteristics and variability.

Eight healthy adult males underwent three 70* head-up tilts within a nine day period. Immediate heart rate responses were monitored for 30 beats following completion of change to upright posture. The pooled data demonstrates a clearly demarcated bimodal heart rate response with a rise in heart rate by the 20th beat and a subsequent fall by the 30th beat. There is a secondary rise in heart rate with continuation of the tilted position. The bimodal response is at variance with several earlier reports. There is a large variability in the immediate heart rate responses, both between subjects of a homogeneous group and within subjects with repeated measurements. The large variability precludes the use of the immediate heart rate responses to passive tilting in autonomic testing.

Adult↗
PubMed1992

Functional significance of post-myocardial infarction left ventricular hypertrophy: a beneficial response.

Hypertrophy of noninfarcted myocardium occurs as a chronic response to myocardial infarction, but no previous study has related the changes in wall thickness to serial changes in left ventricular function. Thus the functional significance of postinfarction hypertrophy is unknown. The purpose of this study was to determine the relationship between the development of postinfarction hypertrophy and the resting left ventricular ejection fraction measured by two-dimensional echocardiography. After occlusion of the proximal left anterior descending coronary artery in 11 dogs, the ejection fraction fell acutely (0.63 +/- 0.08 to 0.33 +/- 0.10, p less than 0.001) and rose at 3.5 months to 0.62 +/- 0.12. End-diastolic thickness of the noninfarcted left ventricle increased (11 +/- 1.0 mm to 13 +/- 1.4 mm, p less than 0.01) as did left ventricular mass (101 +/- 18 gm to 134 +/- 21 gm, p less than 0.0001). Restoration of the ejection fraction toward the baseline value correlated with the increases in left ventricular mass (r = 0.79, p = 0.007) and wall thickness (r = 0.71, p = 0.025). Hypertrophy of the noninfarcted myocardium correlated with the magnitude and approximately paralleled the time course of the improvement in the ejection fraction and therefore may have had a beneficial effect on resting left ventricular function as a chronic adaptation to myocardial infarction.

Animals↗
PubMed1991

Variability in cardiovascular and plasma norepinephrine responses to head-up tilt in healthy human subjects.

Eight healthy, young adult males underwent three separate, 10-min 70 degrees head-up tilts (HUT) over a period of nine days, in order to assess the intra- and inter-individual variability of cardiovascular and plasma norepinephrine (NE) responses to the manoeuvre. Cardiovascular parameters and plasma NE were measured in the basal state and at 2-min intervals during the HUT. The results indicate that: (1) the intra-individual variability is a smaller component of the total variability of both cardiovascular and plasma NE responses to HUT; (2) the variability in cardiovascular parameters is smaller than that in plasma NE levels, both basal and in response to postural stress; (3) there does not appear to be any difference in variability when expressed either as the maximal or the mean response to HUT; and (4) there does not appear to be an increase in the variability of the measured parameters over the duration of the HUT.

Adult↗
PubMed1982

Tumor cell-triggered macrophage-mediated suppression of the T-cell cytotoxic response to tumor-associated antigens. I. Characterization of the cell components for induction of suppression.

A tumor cell-triggered macrophage-mediated suppressor mechanism was demonstrated. It suppressed the induction of specific tumor immunity in the syngeneic, primary mixed lymphocyte tumor cell culture reactions. Preexposure of splenic adherent cells (SAC) to syngeneic FBL-3 tumor cells induced complete suppression of the generation of cytotoxic T-cells. The SAC responsible for inducing suppression were consistent with being macrophages. They were resistant to the treatment of anti-Thy-1.2 antibody plus complement and were relatively radioresistant (at least less than or equal to 750 R X-radiation). Adherent cells obtained from lymph nodes or thymuses acted in the same way as SAC. However, preexposure of peritoneal adherent cells to tumor cells failed to induce suppression. In contrast, the simultaneous presence of peritoneal adherent cells with SAC upon exposure to tumor cells prevented the induction of suppression. These peritoneal cells were also consistent with being macrophages. These results confirmed our previous observations obtained with experiments performed in the allogeneic system. An immunoregulatory circuit existed between two subsets of macrophages that were derived from the population of cells in the peritoneal cavity and from spleen, lymph nodes, or thymus. In the presence of tumor cells, these macrophages produced both positive regulation and negative regulation of the T-cell-mediated cytotoxic response against syngeneic tumor cells. The tumor cells may have utilized the host's own immune network to activate the suppressor mechanisms, thus successfully evading the host's immune surveillance.

Animals↗
PubMed1980

Evaluation of the immunocompetence of macrophages and the generation of T-cell-mediated cytotoxic response against allogeneic tumor cells in tumor bearers.

The present study has examined the competence of peritoneal cells (PC) I of tumor bearers to reverse the immunosuppressive effect of tumor cells, and the ability of the tumor bearers to generate a T-cell-mediated cytotoxic response against allogeneic spleen cells or allogeneic tumor cells. It was found that PC from tumor bearers possess a greater ability to reverse the tumor cell immunosuppression in normal mice. In contrast to normal hosts, the cytotoxic responses of the tumor bearers against allogeneic tumor cells cannot be restored by PC from normal mice or from tumor bearers. The ineffective cytotoxic response in tumor bearers was not due to deficient T responders or T helpers. Rather, it was due to the presence of suppressor cells which were adherent, radioresistant and resistant to anti-Thy-1.2 antibody lysis, and thus were likely to be macrophages. The suppressor macrophages were present only in the spleen and were absent from the peritoneal cavity of the tumor bearers. Their suppressive effect can only be exerted in the presence of tumor cells. These results demonstrate the dichotomy of macrophage function, peritoneal macrophages from the tumor bearers showing increased activity of augmentation of T-cell-response whereas the splenic macrophages cause suppression of the T-cell-response.

Animals↗