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Biomedical subjects

G Pardi

Publications and source records attributed to G Pardi.

At least 55 records · Page 3Linked to original sources

The impact of gestational age and fetal growth on the maternal-fetal glucose concentration difference.

OBJECTIVE: To test whether the human fetus accommodates to the increasing glucose requirements of late pregnancy with an increased maternal-fetal glucose concentration gradient and whether there are differences in pregnancies with fetal growth restriction (FGR) according to clinical severity. METHODS: Umbilical venous glucose concentration was measured in 77 normal pregnancies (appropriate for gestational age [AGA]) and 42 pregnancies complicated by FGR at the time of fetal blood sampling. In 40 AGA and in all FGR cases, a maternal "arterialized" blood sample was collected simultaneously. Growth-restricted fetuses were subdivided into three groups according to fetal heart rate (FHR) recordings and Doppler measurements of the umbilical artery pulsatility index (PI): group 1 (normal FHR and PI; 12 cases), group 2 (normal FHR, abnormal PI; 17 cases) and group 3 (abnormal FHR and PI; 13 cases). RESULTS: In normal pregnancies with increasing gestational age, there was a significant decrease (P < .001) of umbilical venous glucose concentration and a significant increase of the maternal-fetal glucose concentration difference (P < .001). In addition, there was a significant relation between fetal and maternal glucose concentrations (P < .001). In FGR pregnancies, the maternal-fetal glucose concentration difference was significantly higher in fetuses of groups 2 and 3 compared with normal pregnancies and FGR pregnancies of group 1. CONCLUSION: In human pregnancy, the fetal glucose concentration is a function of both gestational age and the maternal glucose concentration. In FGR pregnancies, as an accommodation of the fetus to a restricted placental size and placental glucose transport capacity, the maternal-fetal glucose concentration difference is increased, and this increase is a function of the clinical severity.

Adult↗

Maternal concentrations and fetal-maternal concentration differences of plasma amino acids in normal and intrauterine growth-restricted pregnancies.

OBJECTIVES: Our purpose was to determine whether maternal amino acid concentration changes during gestation in pregnancies with intrauterine growth restriction as in normal pregnancies and to verify whether these changes are related to changes in fetal-maternal differences. STUDY DESIGN: Amino acid concentrations were measured in 5 nonpregnant women, in 11 second-trimester and 10 third-trimester pregnant women with appropriate-for-gestational-age fetuses, and in 23 pregnant women with intrauterine growth restriction. Umbilical venous amino acids were measured at the time of fetal blood sampling. The severity of intrauterine growth restriction was assessed by Doppler velocimetry and fetal heart rate and by evaluation of oxygenation and acid-base balance. RESULTS: In normal pregnant women the maternal concentration of most amino acids was significantly lower in both the second and third trimesters compared with nonpregnant women. In intrauterine growth restriction the maternal concentrations of most essential amino acids were significantly higher than in appropriate-for-gestational-age pregnancies. This observation, coupled with lower fetal amino acid concentrations in intrauterine growth restriction, leads to significantly lower fetal-maternal differences. CONCLUSIONS: Normal pregnant women have a significant decrease in amino acid concentrations compared with nonpregnant women, whereas in intrauterine growth restriction maternal amino acids are reduced less, Significantly lower fetal-maternal concentration differences are present in intrauterine growth restriction, independent of the degree of severity.

Adult↗

HIV-1 proviral DNA polymerase chain reaction detection in chorionic villi after exclusion of maternal contamination by variable number of tandem repeats analysis.

OBJECTIVE: The study of the placental HIV infection in cases of seropositive pregnant women after exclusion of maternal contamination of chorionic villi samples by variable number of tandem repeats (VNTR) analysis. METHODS: We studied 30 HIV-positive women: 17 terminated their pregnancy (11 in the first trimester and six in the second) and 13 delivered at term (one was a twin gestation). We selected chorionic villi and ruled out maternal contamination by VNTR analysis. DNA from chorionic villi and cord and maternal blood were tested for HIV by PCR. All infants underwent a paediatric follow-up. RESULTS: All maternal blood samples tested positive for HIV-1 by polymerase chain reaction. No maternal contamination was revealed and HIV was found in six out of 11 first trimester placentas, in all second trimester samples, and in 10 out of 14 at term. Cord blood tested positive in all second trimester cases and in seven out of 14 liveborns. In no case was HIV found in cord blood without infection of the corresponding placenta; conversely, three placentas tested positive but cord blood was negative. Two infants were HIV-positive, 11 were uninfected (one case was lost to follow-up). CONCLUSION: Our study indicates that HIV-1 can infect the placenta from first trimester onwards. HIV was found in two-thirds of our cord blood samples but it is possible that some viral DNA in cord blood may have come from infected placental cells. Additional studies are needed to assess the source of HIV in cord blood and the possible contribution of placental or maternal cells infected with HIV to vertical transmission of the virus.

Blotting, Southern↗

Vertical transmission of HIV-1: maternal immune status and obstetric factors. The European Collaborative Study.

OBJECTIVE: To estimate the effect of maternal factors and events around the time of delivery on HIV-1 vertical transmission risk. DESIGN: Prospective study. SETTING: Twenty-two obstetric and paediatric clinics in seven European countries. PATIENTS OR OTHER PARTICIPANTS: Mothers identified as HIV-infected before or at delivery and their children. MAIN OUTCOME MEASURE: Paediatric HIV infection. RESULTS: By November 1995, 1846 mothers with 1945 children had been enrolled. The vertical transmission rate was 16.4% (95% confidence interval, 14.5-18.3). Parity, maternal age, race, mode of HIV acquisition, injecting drug use and sex of infant were not statistically significantly associated with risk of transmission. Children delivered vaginally were more likely to be infected than those delivered by Caesarean section. However, in vaginal deliveries the procedures used, duration of ruptured membranes or length of second-stage labour were not related to transmission. Transmission increased almost linearly with decreasing CD4 cell count, but there was no such trend for CD8 cell count. Women with CD4 cell counts below 200 x 10(6)/l were significantly more likely to deliver early (chi 2 for trend, 14.02; P < 0.001). Very premature infants were at increased risk of infection, but after about 35 weeks gestation the transmission rate remained stable, with no increase in late pregnancy. This trend was confirmed after allowing for maternal CD4 cell count. CONCLUSIONS: The rate of vertical transmission increases linearly with decreasing maternal CD4 cell count. Women with fewer than 200 x 10(6) CD4 cells/l have an increased risk of premature delivery, which would affect timing of interventions. The stable transmission rate after 35 weeks gestation suggests little acquisition of infection during late pregnancy.

Europe↗

Color-Doppler velocimetry of uterine arteries in pregnant and nonpregnant patients during multiovulation induction for IVF.

OBJECTIVES: To evaluate uterine artery resistance during multiovulation induction in relation to the implantation rate in patients attending in vitro fertilization (IVF) cycles. PATIENTS: Multiovulation induction for IVF was monitored by daily determination of the pulsatility index (PI) of the uterine arteries, obtained by a transvaginal probe (6.5 MHz) implemented with color-flow imaging. Doppler data were obtained from 5 days before hCG administration to the day of follicular aspiration. One IVF cycle was monitored in 70 patients. In 17 patients, 41 IVF cycles were monitored until a successful attempt occurred. RESULTS: In the 70 patients studied during one IVF attempt, the PI of the uterine arteries significantly varied (P < 0.001) in the different phases of the cycle. In the 24 patients who conceived, a significantly lower PI (P < 0.03) was found throughout the cycle. This result was mainly due to a highly significant difference of PI values observed the day after hCG administration (P < 0.005). In the 17 patients who conceived after 1 to 4 negative in vitro fertilizations, no significant difference in PI was observed in the uterine artery resistance in cycles in which implantation was or was not successful. CONCLUSIONS: Uterine artery resistance varies significantly during phases of the induction therapy. Uterine artery resistance is lower throughout the course of multiovulation induction in patients with higher pregnancy rates. The PI on the day after hCG administration was the best index of pregnancy rate. Low uterine artery resistance was present even in negative attempts in patients who eventually achieved a successful implantation. PI values < or = 3 can be considered a favorable prognostic factor for future IVF cycles.

Adult↗

Laparoscopically assisted vaginal removal of ovarian dermoid cysts.

Dermoid cysts were diagnosed by transvaginal sonography in 19 patients who subsequently underwent laparoscopy to confirm the nature and extent of the lesion and the mobility of the adnexa. Eighteen patients underwent surgery after the ovary was exteriorized through a posterior colpoceliotomy. No intraoperative complications were observed, and sonographic follow-up at 3 and 6 months after surgery showed a normal sonographic ovarian pattern. Laparoscopically assisted vaginal removal of dermoid cysts should be considered as an alternative to laparotomy and operative laparoscopy in cases when adnexal mobility is proven and vaginal extraction is feasible.

Adult↗

Peak velocity of the outflow tract of the aorta: correlations with acid base status and oxygenation of the growth-retarded fetus.

OBJECTIVE: To correlate the peak velocities of the aortic outflow tract of growth-retarded fetuses with fetal acid base status and oxygenation measured in utero. METHODS: Thirty-one growth-retarded fetuses with abnormal umbilical pulsatility index (PI) measurements underwent fetal blood sampling. Blood pH, carbon dioxide pressure (PCO2), oxygen pressure (PO2), oxygen saturation, lactate concentration, and hemoglobin concentration were measured. Using color Doppler equipment, we measured the peak velocities of the outflow tract of the aorta, pulmonary artery, and ductus arteriosus before fetal blood sampling. RESULTS: The peak velocities measured in the outflow tract of the aorta, pulmonary artery, and ductus were significantly lower in growth-retarded fetuses than in 140 normal fetuses of comparable weight. The correlation observed between pulmonic and aortic peak velocities was significant (r = 0.84), as was that between pulmonic and ductal peak velocities (r = 0.74). Growth-retarded fetuses with abnormal aortic peak velocities had significantly lower values of PO2, oxygen content and pH, and had higher lactate concentration and PCO2 than did growth-retarded fetuses with normal peak velocities. Estimated fetal weight and umbilical PI (mean +/- standard deviation) were not significantly different in these two groups. Moreover, significant direct correlations were found between proximal aortic peak velocities and lactate concentrations (correlation coefficient 0.71, P < .0001) and O2 content (P < .02, r = 0.42). CONCLUSION: For growth-retarded fetuses, Doppler peak velocity in these vessels is significantly lower than in normal fetuses of comparable weight. Aortic, pulmonic, and ductal peak velocity correlated significantly. Growth-retarded fetuses with abnormally low peak velocity in the outflow tract of the aorta have a higher risk of acidemia and hypoxia than those with normal velocities.

Aorta↗

In vivo placental transport of glycine and leucine in human pregnancies.

L-[1-13C]Glycine and L-[1-13C]leucine were infused as a bolus into 12 pregnant patients carrying normal fetuses before fetal blood sampling at gestational ages ranging from 20 to 37 wk. Maternal venous samples were obtained every 2-3 min for 15 min after the bolus infusion. Fetal samples were obtained from the umbilical vein within 15 min of the bolus. Amino acid plasma enrichments (molar percent enrichment) were determined by gas chromatography-mass spectroscopy and their concentrations by ion exchange chromatography. The ratios of glycine and leucine transfer were assessed from fetal/maternal enrichment ratios for each amino acid. We now report that over the gestational age range of 20-37 wk, under relatively undisturbed fetomaternal conditions (fetal blood sampling), human placental glycine transfer is limited, with a glycine/leucine ratio = 0.16 +/- 0.02. We hypothesize that, in human pregnancies, the relative rates of in vivo transplancental transport of amino acids can be assessed indirectly utilizing fetal blood sampling and stable isotope methodology. The application of this approach to leucine and glycine demonstrates that the transfer of leucine is rapid (demonstrable in seconds), whereas that of glycine is more limited.

Adult↗

Fertility restoration by seminal tract washout in ejaculatory duct obstruction.

A complex case of secondary sterility due to excretory azoospermia-dry ejaculation is reported. Transrectal ultrasonography and vaso-vesiculography revealed post-inflammatory total obstruction of the right ejaculatory duct. Excluding small radiolucent concrements in the seminal vesicle, no anatomical anomalies were identified on the left side. By performing antegrade seminal tract washout with saline solution it was possible to clear both seminal ducts and restore fertility in our patient. In select cases seminal tract washout may be a valid alternative to the conventional transurethral surgical approach for acquired obstruction of the ejaculatory ducts.

Ejaculatory Ducts↗

Development of dopaminergic neurons in the human mesencephalon and in vitro effects of basic fibroblast growth factor treatment.

The origin and development of the mesencephalic dopaminergic (mesDA) neurons within the substantia nigra were characterized in human embryos from Postconception (PC) Week 5.0 to 12.0. Tyrosine hydroxylase (TH) immunoreactive cells were first demonstrated in the ventral mesencephalon at PC Week 5.5 next to the ventricular zone. Cell migration and neurite outgrowth of TH-positive neurons were timed. Early expression of ganglioside GM1 was demonstrated in developing neurons. Glial fibrillary acidic protein (GFAP) was first observed at PC Week 10.0 instead, after the dopaminergic neurotransmitter phenotype expression. In vitro complementary information was obtained: TH-positive cells represented about 3% of the total cell population after a week in culture, based upon accurate anatomical dissection. They tended to form microaggregates and to grow in close contact with glial cells. MesDA neuronal expression of TH activity was measured by a biochemical microassay. TH-positive cells responded to basic fibroblast growth factor (bFGF) both with increased TH activity and neuronal survival. bFGF effects were mediated by the proliferative action on glial cells. Astroglial GFAP-positive cells express nerve growth factor-low-affinity receptor in culture. Information on in vitro and in vivo sequences of mesDA neuronal development and their response to identified neurotrophic molecules may be invaluable for selection of the most appropriate tissue donor age for brain grafting and development of alternative treatment strategies for Parkinson's disease.

Cell Movement↗

Fetal blood sampling during pregnancy: risks and diagnostic advantages.

A review is provided on the use of fetal blood sampling during pregnancy. Informations on the technique, its indications, risks and benefits are provided. In addition, the application of fetal blood sampling in cases of intrauterine growth retardation as well as some metabolic features of intrauterine life are discussed.

Blood Specimen Collection↗

Diagnostic value of blood sampling in fetuses with growth retardation.

BACKGROUND: Fetuses with intrauterine growth retardation are delivered if they have evidence of distress, as manifested by abnormalities in the fetal heart rate and umbilical-artery blood flow. We studied whether umbilical-blood sampling might provide further information useful for management. METHODS: We measured hemoglobin and lactate concentrations, oxygen content, pH, blood gas levels, and base deficit in umbilical-vein blood and correlated these measurements with the heart rate and umbilical-artery wave forms recorded by Doppler velocimetry in 56 fetuses with growth retardation. Twenty-one fetuses had normal heart rates and normal results of velocimetry, 24 had normal heart rates and abnormal results of velocimetry (indicative of decreased diastolic flow), and 11 had abnormal heart rates and abnormal results of velocimetry. RESULTS: None of the 21 fetuses with normal heart rates and velocimetry had hypoxia or acidemia. Of the 24 fetuses with normal heart rates and abnormal velocimetry, 4 (17 percent) had moderate lactic acidosis, 1 (4 percent) had a low pH value, and 3 (12 percent) had hypoxia. Of the 11 fetuses with abnormal heart rates and velocimetry, 7 (64 percent) had lactic acidosis, low blood oxygen content, and low pH values. The absence of end-diastolic flow increased the risk of hypoxia and acidemia. The proportion of fetuses with elevated hemoglobin concentrations was similar among the three groups. CONCLUSIONS: Assessment of fetal oxygenation and acid-base balance is not indicated in fetuses with growth retardation if their heart rates and the results of velocimetry are normal. If the results of velocimetry are abnormal, fetal-blood sampling can distinguish fetuses that have growth retardation alone from those that also have hypoxia and acidosis, and thus may aid in determining the optimal time of delivery.

Acidosis↗

An evaluation of fetal glucogenesis in intrauterine growth-retarded pregnancies.

The presence of fetal glucogenesis was evaluated in nine patients with pregnancies complicated by intrauterine growth retardation (IUGR) at the time of fetal blood sampling (FBS) between 29 and 35 weeks of pregnancy. Eight were singleton pregnancies and one was a twin pregnancy in which blood samples were obtained from both twins. A maternal primed-constant infusion of D(U-13C]glucose was performed, and the presence of fetal glucogenesis was assessed by a comparison of steady-state maternal and fetal glucose enrichments. No significant difference was present between maternal and fetal molar percent excess ([MPE] P = .97), and the mean fetal to maternal (F/M) MPE ratio (0.99 +/- 0.01) was not significantly different from 1 (P = .76). F/M MPE ratio was independent of the time of FBS and umbilical venous glucose and lactate concentrations. Thus fetal glucogenesis is not demonstrable in a group of fairly severe growth-retarded fetuses after an overnight fast with this relatively noninvasive approach.

Adult↗

Impact of conceptus mass on glucose disposal rate in pregnant women.

The impact of an increasing fetal and placental mass on maternal glucose disposal rate (GDR) was studied in 17 pregnant women. Eleven pregnancies were singleton pregnancies, five were twin and one was a triplet pregnancy. Both the maternal fasting glucose concentration [Glc] and the total fetal and placental weight (W) were significantly correlated with an increased maternal GDR. Glucose concentration and conceptus weight were interdependent. The multiple linear regression of glucose disposal rate on glucose concentration and total weight is given by GDR = -1.573 + 0.176W + 0.932[Glc] +/- 0.24, r2 = 0.52, P < 0.01. These data are utilized to estimate the glucose utilization rate of the human conceptus at a fasting glucose concentration of 3.9 mM with a range of 10-15 mg.kg-1.min-1. Maternal GDR increases with increasing glucose concentration at a rate similar to that reported for newborn infants, consistent with a high glucose utilization by the uterus.

Adult↗

Insemination of HIV-negative women with processed semen of HIV-positive partners.

Many HIV-discordant couples want to have children so much that they are willing to abandon condom-protected sexual intercourse irrespective of the risks. Previous testing in our laboratory showed that gradient centrifugation followed by a swim-up procedure effectively removed HIV-1-infected cells from the semen of HIV-seropositive men. 85 HIV-discordant couples were screened for fertility; 29 women were found suitable for a timed insemination course with the processed semen of their HIV-seropositive partner. None of the inseminated women seroconverted, and 17 pregnancies were achieved in 15 women. All 10 babies born to these mothers remain HIV seronegative. The findings may help in the counselling of such couples and also give them hope of having healthy babies.

Centrifugation, Density Gradient↗