Biomedical subjects

G Mari

Publications and source records attributed to G Mari.

At least 37 records · Page 2Linked to original sources

PubMed1999

The Doppler cerebroplacental ratio and perinatal outcome in intrauterine growth restriction.

OBJECTIVE: Our purpose was to determine whether the Doppler cerebroplacental ratio predicts perinatal outcome in fetuses at risk for intrauterine growth restriction. STUDY DESIGN: The middle cerebral and umbilical artery pulsatility index values were measured in 203 fetuses at risk for intrauterine growth restriction, of which 123 were delivered <3 weeks after the last Doppler examination. Perinatal outcome was categorized as (1) birth weight <10th percentile, (2) birth weight <5th percentile, (3) perinatal complications (meconium-stained fluid, cesarean section for fetal distress, 5-minute Apgar score <7, perinatal death, neonatal intensive care unit stay >24 hours, hypoglycemia, or polycythemia), (4) birth weight <10th percentile plus complications, and (5) birth weight <5th percentile plus complications. The cerebroplacental ratio (middle cerebral artery pulsatility index divided by umbilical artery pul-satility index) values were expressed as multiples of the normal median. Receiver-operator characteristic curves (sensitivity vs false-positive rates) were plotted for the prediction of each category of perinatal outcome and the areas under the curves were determined. Stepwise logistic regression analyses were used to determine whether the cerebroplacental ratio improved outcome prediction over umbilical artery Doppler imaging alone. RESULTS: There was a statistically significant increase in perinatal morbidity and mortality in cases with an abnormal cerebroplacental ratio. The areas under the receiver-operator curves characteristics for the prediction of perinatal outcome with use of the cerebroplacental ratio were statistically very significant. For birth weight <10th percentile we noted P <.001, with P <.0001 for each of the other 4 outcome categories. As shown by regression analyses, the cerebroplacental ratio appeared to improve the prediction of perinatal outcome compared with umbilical artery velocimetry alone. An interesting finding was that the cerebroplacental ratio did not appear to correlate significantly with outcome in fetuses at >34 weeks. CONCLUSION: Doppler identification of the fetal "brain-sparing" effect strongly predicts outcome in fetuses at risk for intrauterine growth restriction. The brain-sparing effect predicted perinatal problems only in fetuses <34 weeks' gestation at the Doppler examination.

Birth Weight↗

PubMed1999

Assessment of Doppler velocimetry of the fetal umbilical artery by multigate spectral Doppler scanning and traditional pulsed Doppler ultrasonography plus color flow mapping.

The Doppler signal of blood flow originates from the sonographic scattering from the circulating red blood cells. However, the physics of blood flow is complex as expressed by the Bernoulli equation, and the flow velocity at different positions in the laminar flow of the same vessel is variable. Using multigate spectral Doppler scanning, we recorded multiple Doppler flow signals over a segment of the umbilical artery and compared the results with traditional pulsed Doppler ultrasonography. The intraobserver variations of the pulsatility index, the resistive index, and the systolic-to-diastolic ratio were evaluated in 30 human fetuses between 29 and 42 weeks of gestation. The correlation coefficient was calculated to establish the relationship between the results of multigate spectral Doppler scanning and the traditional pulsed Doppler ultrasonographic method. The Doppler indices of these two measurements are all significantly correlated. However, since a significant difference exists between the Doppler flow measurements of multigate spectral Doppler scanning and the traditional pulsed Doppler ultrasonographic method, the range of measurement agreement for these two methods suggests that this difference should be taken into account in the interpretation of Doppler flow velocity measurements.

Female↗

PubMed1998

Fetal splenic size in anemia due to Rh-alloimmunization.

OBJECTIVE: To determine whether fetal splenic enlargement predicts anemia in Rh-alloimmunized nonhydropic singleton fetuses. METHODS: Splenic circumference was measured before funipuncture in 21 singleton pregnancies on 47 occasions. The spleen was imaged in an axial section of the fetal abdomen close to the level used for measurement of the abdominal circumference. The splenic length and width were measured and the circumference calculated by the formula (length and width x 1.57). One measurement per patient was used for each analysis. Splenic circumference was measured and expressed as multiples of the normal median (MoM) for gestational age. One hundred twenty-one cases were used to provide cross-sectional normative data. The expected median splenic circumference values were derived from a normal group. Fetal anemia was defined as hemoglobin deficit, ie, mean hemoglobin concentration for gestation minus the measured value. Anemia was defined as hemoglobin deficit exceeding 2 g/dL, and severe anemia as hemoglobin deficit exceeding 5 g/dL. Receiver operator characteristics curves for the prediction of anemia using different splenic circumference (MoM) values were constructed. RESULTS: Splenic circumference was an excellent predictor of severe anemia in cases with no prior transfusion: sensitivity 100% and specificity 94.7% (area under the curve = .97, P < .03). The measurement did not correlate significantly with severe anemia in the group with prior transfusion (area under the curve = .73, P = .19). CONCLUSION: Splenomegaly is sensitive for the detection of severe anemia in nonhydropic Rh sensitized cases without prior transfusion. The splenic enlargement could be explained by extramedullary erythropoiesis.

Adult↗

PubMed1998

Arterial and venous Doppler velocimetry in the severely growth-restricted fetus and associations with adverse perinatal outcome.

OBJECTIVE: To evaluate the association between arterial and venous Doppler waveforms and adverse perinatal outcome in severe intrauterine growth restriction. DESIGN: Fetuses between 26 and 32 weeks' gestation with ultrasonographically estimated fetal weight below the 5th centile were included in this prospective study. The last Doppler measurements of the umbilical artery, ductus venosus, umbilical vein and middle cerebral artery before delivery and adverse outcome parameters without gestational age independence were used for statistical analysis. Adverse outcome parameters were defined as the following: fetal demise or neonatal death in the first 30 days of life; 5-min Apgar score of < 7; intubation at birth; retinopathy of prematurity; respiratory distress syndrome; necrotizing enterocolitis; stay in neonatal intensive care unit of more than 60 days; intraventricular hemorrhage; periventricular leukomalacia. RESULTS: Nineteen fetuses fulfilled the inclusion criteria. Perinatal death, low 5-min Apgar values and necrotizing enterocolitis were gestational age-independent adverse outcome parameters. Abnormal Doppler velocimetry of the ductus venosus was the only significant parameter associated with perinatal death and low 5-min Apgar scores. None of the Doppler parameters predicted necrotizing enterocolitis. CONCLUSION: Our data suggest that management of severely growth-restricted fetuses may be aided by the study of ductus venosus Doppler velocimetry.

Blood Flow Velocity↗

PubMed1998

Can a single measurement of amniotic fluid delta optical density be safely used in the clinical management of Rhesus-alloimmunized pregnancies before 27 weeks' gestation?

BACKGROUND: To assess the efficacy of a single measurement of amniotic fluid optical density deviation at 450 nanometers in predicting fetal anemia in Rhesus-alloimmunization before 27 weeks gestation. METHODS: In this cross-sectional study, fetal blood and amniotic fluid samples from 43 Rhesus-alloimmunized pregnancies at 18 to 26 weeks gestation were obtained under ultrasound guidance. Amniotic fluid samples were scanned by spectrophotometry for optic density at various wavelengths. Deviation at 450 nanometers was calculated between 550 and 365 nanometers. The fetuses were divided into three groups based on their hematocrit levels and the predictive efficacy of optic density zones for anemia was evaluated. RESULTS: A high number of false positive and false negative results were observed when the delta-amniotic fluid optical density of fetuses at risk for anemia was plotted to the zones recently proposed to manage Rhesus-alloimmunized pregnancies. CONCLUSIONS: These data confirm previous results that the diagnosis of fetal anemia in Rhesus-alloimmunized pregnancies before 27 weeks' gestation cannot be accurately made by a single measurement of amniotic fluid optical density at 450 nanometers.

Amniocentesis↗

PubMed1997

Superior mesenteric artery Doppler velocimetry and ultrasonographic assessment of fetal bowel in gastroschisis: a prospective longitudinal study.

OBJECTIVE: Our purpose was to determine whether Doppler velocimetry of the superior mesenteric artery and its mesenteric branches and ultrasonographic assessment of bowel can predict postnatal outcome in fetuses with gastroschisis. STUDY DESIGN: The normal reference range for the superior mesenteric artery pulsatility index was determined by studying 161 normal fetuses. Over a 24-month period superior mesenteric artery pulsatility index, superior mesenteric artery mesenteric branches systolic/diastolic ratio, bowel diameter, and bowel wall thickness were prospectively and longitudinally obtained from 17 fetuses with gastroschisis. Poor neonatal outcome was defined by bowel resection or staged repair of the defect or a hospital stay > 50 days. RESULTS: Doppler velocimetry of the superior mesenteric artery and its mesenteric branches proved minimally useful in prognosticating neonatal outcome. No difference was found in the superior mesenteric artery pulsatility index between the good and poor neonatal outcome groups (p = 0.99). Longitudinal data analysis on all fetuses with gastroschisis showed an increase in bowel diameter with advancing gestation (p < 0.0001). A greater rate of increase in bowel diameter with advancing gestation was noted in the poor-neonatal-outcome group compared with the good-neonatal-outcome group (p < 0.01). Mean bowel diameter obtained before delivery was significantly greater in the poor-neonatal-outcome group (p = 0.03). Bowel diameter obtained at 28 to 32 weeks was the best predictor of poor neonatal outcome. A cutoff value of bowel diameter > 10 mm at 28 to 32 weeks had a sensitivity of 83%, a specificity of 88%, a positive predictive value of 83%, and a negative predictive value of 88% for poor neonatal outcome. CONCLUSIONS: Doppler velocimetry of the superior mesenteric artery and its branches is not predictive of poor neonatal outcome in fetuses with gastroschisis. A bowel diameter > 10 mm between 28 and 32 weeks appears to be the best predictor of poor neonatal outcome. This newly defined variable warrants further investigation given its significant predictive power.

Abdominal Muscles↗

PubMed1997

Modified neck dissection in the treatment of differentiated thyroid carcinoma.

The prognosis of differentiated carcinoma of the thyroid has been reported to be extremely favourable. Previous studies have concluded that lymph node metastasis do not affect survival rates in patients with differentiated thyroid carcinoma. Therefore, nodal metastasis has not been evaluated as a prognostic factor in recent definitions of risk groups. To determine the significance of nodal disease, we reviewed 219 consecutive patients with differentiated thyroid cancer (191 papillary, 14 follicular and 14 Hurtle cell carcinomas). Fifty-five patients were treated with modified neck dissection and all of them received adjuvant radioiodine. There were recurrences in 25 patients (11.4%), with follow-up ranging from 6 months to 14 years. Systemic disease occurred synchronously in two patients, and four patients died of thyroid carcinoma.

Adenocarcinoma↗

PubMed1997

The effect of intravascular blood transfusion on the flow velocity waveform of the portal venous system of the anemic fetus.

Our objective was to assess flow velocity waveforms of the portal venous system of the anemic fetus prior to and immediately following intravascular transfusion. Color-guided pulsed Doppler was used to obtain flow velocity waveforms from the fetal portal vein in 14 anemic fetuses that were transfused in utero for rhesus alloimmunization The portal vein velocity pattern was defined as continuous when no change in velocity during the cardiac cycle was noted. It was defined as pulsatile when a deflection of the wave was present. The flow velocity waveforms were quantified by using the ratio between the peak (highest, H) and the nadir (lowest, L) velocities (H/L ratio). Fourteen intravascular transfusions were performed. Gestational age ranged from 19.5 to 35 weeks (mean +/- SD, 26.7 +/- 5.3 weeks). The hematocrit ranged from 5.9 to 31.2% (mean +/- SD, 20.3 +/- 9%) prior to transfusion; after transfusion it was between 24.8 and 56.7% (mean +/- SD, 42 +/- 10.4%). In six cases (43%) the waveforms were pulsatile prior to transfusion; in the other eight (57%) they were continuous. The pulsatile pattern was present following transfusion in 13 cases (93%, p < 0.05). The mean of the H/L ratio was 1.3 +/- 0.38 prior to transfusion and 2.0 +/- 0.86 after transfusion (p < 0.05). Because the portal vein has continuous non-pulsatile flow in the normal fetus, the presence of pulsatility in the waves of six anemic fetuses (43%) may suggest portal hypertension. Compared to normal fetuses, there was an increased number of cases with pulsation, and even more so after transfusion. The pattern corresponds to findings in children with portal hypertension.

Anemia↗

PubMed1997

[Plasma protein adsorption on variously treated +polybutylene terephthalate].

BACKGROUND: The aim of the research was the evaluation of plasmatic protein adsorption on untreated polybutylene terephthalate, corona treated polybutylene terephthalate and polyvinylacetate coated corona treated polybutylene terephthalate. METHODS: Total proteins, albumin, immunoglobulins, fibrinogen, insulin and ostecalcin were determined on plasma after contact with these polymers. RESULTS: Unsignificant variations were observed for the assayed proteins. CONCLUSIONS: The conclusions are drawn that the tested materials do not adsorbe significantly the most important plasmatic proteins.

Adsorption↗

PubMed1997

Clinical features of cystic fibrosis patients with rare genotypes in Saguenay Lac-Saint-Jean (Quebec, Canada).

We describe the clinical features of six cystic fibrosis (CF) patients from Saguenay Lac-Saint-Jean who bear rare genotypes. Two patients with a delta F508/I148T genotype had pancreatic insufficiency, as did two patients compound heterozygous for the 621 + 1G-->T mutation who also had a major growth retardation. One CF adult who carried a delta F508/Q890X genotype had meconium ileus and bronchiectasis. The sixth patient (A455E/R117C) had borderline sweat chloride concentrations; the diagnosis of cystic fibrosis had remained doubtful until the molecular analysis showed the presence of two CF mutations. The seventh patient with a delta F508/R1158X genotype experienced several complications and is now 43 years old.

Adult↗

PubMed1996

Flow velocity waveforms of the ductus arteriosus in appropriate and small-for-gestational-age fetuses.

OBJECTIVES: To assess ductus arteriosus velocity waveforms in the appropriate and small-for-gestational-age (SGA) fetuses. STUDY DESIGN: Ductus arteriosus flow velocity waveforms were obtained in 14 normal fetuses in a longitudinal study and in 139 normal fetuses in a cross-sectional study with pulsed and continuous Doppler ultrasonography. Ductus velocity waveforms were also determined in 25 SGA fetuses whose gestational age ranged between 20 and 34 weeks (mean +/- SD: 30 +/- 4.1 weeks). RESULTS: Mathematical modeling demonstrated that the peak systolic velocity, lowest diastolic velocity, and mean velocity of the ductus arteriosus increased with advancing gestation in both the longitudinal and cross-sectional study, but considerable individual variability was seen in the longitudinal study. The pulsatility index did not change significantly. The ductal parameters were in the normal range in all the SGA fetuses. CONCLUSIONS: The blood velocity of the ductus arteriosus increase with advancing gestation. Our results suggest that Doppler ultrasonographic study of the fetal ductus arteriosus, unlike Doppler study of the umbilical artery or middle cerebral artery, is not useful as an indicator of adverse fetal outcome.

Blood Flow Velocity↗

PubMed1996

Cerebellar Doppler velocimetry in the appropriate- and small-for-gestational-age fetus.

OBJECTIVE: To compare superior cerebellar artery flow velocity waveforms in the appropriate-for-gestational-age (AGA) and the small-for-gestational-age (SGA) fetus. METHODS: Superior cerebellar artery velocity waveforms were obtained prospectively from 172 AGA fetuses at 17-41 weeks' gestation. The pulsatility index (PI) was used to quantify the waveforms. Superior cerebellar artery velocity waveforms were also obtained from 30 SGA fetuses divided into group A (n = 15), with a normal umbilical artery PI, and group B (n = 15), with an abnormal umbilical artery PI. The transverse cerebellar diameter was measured in all SGA fetuses. RESULTS: The superior cerebellar artery PI was best represented by a second-order polynomial equation [PI = 0.145 + 0.101 x (gestational age) - 0.00197 (gestational age)2]. Small-for-gestational-age fetuses of group A had a superior cerebellar artery PI in the normal range, whereas 13 of 15 fetuses of group B (86.7%) had a PI value less than the individual 95% confidence interval. The transverse cerebellar diameter in group A fetuses was in the normal range in ten of 15 cases, whereas it was in the normal range for all group B fetuses. CONCLUSION: Small-for-gestational-age fetuses with an abnormal umbilical artery PI have "cerebellar-sparing effect," as suggested by a superior cerebellar artery PI less than the normal range and a normal transverse cerebellar diameter.

Arteries↗

PubMed1996

Adrenal artery velocity waveforms in the appropriate and small-for-gestational-age fetus.

The purpose of this study was to compare adrenal artery flow velocity waveforms in the appropriately grown and the small-for-gestational-age fetus. Adrenal artery flow velocity waveforms were prospectively obtained from 131 appropriate- and 21 small-for-gestational-age fetuses with pulsed Doppler ultrasonography. The success rate in recording the adrenal artery was 84% (131/155) and 100% in the appropriate- and small-for-gestational-age fetuses, respectively. The pulsatility index (PI) was used to quantify the waveforms. The PI in the appropriate-for-gestational-age fetuses decreased linearly with gestational age (PI = 1.7-0.016 x gestational age). In ten small-for-gestational-age fetuses the adrenal artery PI was below the 95% confidence interval. Small-for-gestational-age fetuses with abnormal adrenal artery PI had a significantly higher incidence of fetal heart rate decelerations, preterm delivery and Cesarean sections when compared to small-for-gestational-age fetuses with normal adrenal artery PI. Our data indicate that the PI of the adrenal artery in the normal fetus decreases with advancing gestation, and they suggest that in the small-for-gestational-age fetus there is an increased blood flow to the adrenal gland. We postulate that management of the small-for-gestational-age fetus may be aided by the study of the adrenal artery flow velocity waveforms.

Adrenal Glands↗

PubMed1996

Is the fetal brain-sparing effect a risk factor for the development of intraventricular hemorrhage in the preterm infant?

The intrauterine identification of fetuses at risk of developing intraventricular hemorrhage would be helpful to the perinatologist, in light of the recent results which suggest that indomethacin given to the infant reduces the risk of developing intraventricular hemorrhage. We hypothesized that fetuses undergoing brain sparing, as identified by a lowered pulsatility index (PI) in the middle cerebral artery, and delivered prior to 34 weeks may differ in terms of being at risk for intraventricular hemorrhage from those fetuses without the brain-sparing effect. The middle cerebral artery PI was studied in 43 fetuses between 25 and 33.6 weeks' gestation. The pregnancies were complicated by pre-eclampsia, intrauterine growth restriction (IUGR) and preterm labor. A cranial sonogram was performed during the first postnatal week in all the neonates. Intraventricular hemorrhage was present in 6/22 infants with a normal middle cerebral artery PI (group A) and 0/21 with an abnormal middle cerebral artery PI (group B) (p < 0.05). The mothers of the six fetuses who developed intraventricular hemorrhage underwent preterm labor. IUGR fetuses and pre-eclampsia were more common in group B. No difference was found between the two groups when the following variables were compared: (1) gestational age at the time of the Doppler study; (2) gestational age at delivery; (3) antenatal exposure to steroids; (4) antenatal exposure to magnesium; (5) Apgar score greater than 6 at 5 min; (6) respiratory distress syndrome in the newborn; (7) necrotizing enterocolitis; (8) Cesarean section; and (9) sepsis in the infant. Although the mean birth weight was significantly lower in group B than group A, no fetus in this group developed intraventricular hemorrhage. The fetal brain-sparing effect, pre-eclampsia and IUGR were associated with a lower risk of neonatal intraventricular hemorrhage than was preterm labor. Preterm labor appears to be a key factor in the development of intraventricular hemorrhage and must be included when testing associations with intraventricular hemorrhage.

Cerebral Arteries↗

PubMed1995

A postgraduate teaching course in laparoscopic surgery.

A teaching course in laparoscopic surgery was addressed to 21 young postgraduates as a part of their general surgery program with the aim of making them familiar with the basic principles of laparoscopic surgery. The methodology was based on tutorial teaching and "learning by problems"; the students worked in little groups elaborating check lists, discussing problems, and practising with laparoscopic training devices. Theoretical learning, practical abilities, and efficacy of tutorial teaching were investigated at the end of the course: the participant's understanding of instrument function, mastering of equipment, and solutions to clinical problems were good, as were the efficiency and pleasantness of the didactic method. Tutorial teaching seems to be a valid model for basic training in laparoscopic surgery in a modern medical education program.

Education, Medical, Continuing↗

PubMed1995

Doppler flow velocimetry of the splenic artery in the human fetus: is it a marker of chronic hypoxia?

OBJECTIVE: The aim of this investigation was to describe splenic artery flow velocity waveforms in the appropriate- and small-for-gestational-age human fetus. STUDY DESIGN: Splenic artery flow velocity waveforms were prospectively obtained from 95 appropriate- and 15 small-for-gestational-age fetuses with pulsed Doppler ultrasonography. The resistance index was used to quantify the Doppler waveform. RESULTS: A second-degree polynomial model expressed the changes of the resistance index in appropriate-for-gestational-age fetuses with advancing gestation (y = 0.057x [Weeks] - 0.001x2, r = 0.53, p < 0.001). In 14 of 15 (93%) small-for-gestational-age fetuses the splenic artery resistance index was below the mean for gestational age. In five of 15 (33%) small-for-gestational-age fetuses the resistance index of the splenic artery was < 2 SEMs. A trend toward a higher hematocrit was noted in the five fetuses with splenic artery resistance index values < 2 SEMs (50.2%) compared with other small-for-gestational-age fetuses (43.0%). CONCLUSION: Our results suggest that some small-for-gestational-age fetuses have decreased resistance at the level of the splenic artery. We postulate that the increased erythropoietin level, stimulated by hypoxia, results in decreased resistance at the level of the splenic artery in small-for-gestational-age fetuses. Finally, management of the small-for-gestational-age fetus may be aided by the study of the splenic artery waveforms.

Blood Flow Velocity↗

PubMed1995

Single umbilical artery: does it matter which artery is missing?

OBJECTIVE: Our purpose was to determine whether the presence of congenital anomalies in fetuses with a single umbilical artery is related to the side of the missing artery. STUDY DESIGN: During an 18-month prospective study, the side of the missing artery was identified in all pregnancies with a single umbilical artery (n = 77). Targeted sonograms and perinatal follow-up were obtained. RESULTS: The left umbilical artery was absent in 56 of 77 (73%) fetuses, compared with 21 of 77 (27%) for the right artery, p < 0.0001. Congenital anomalies occurred in 20 of 77 (26%) fetuses, with 16 of 56 (29%) in those with absence of the left artery and 4 of 21 (19%) in those with absence of the right artery, p = 0.561. Complex congenital anomalies occurred in 9 of 20 (45%) fetuses. All complex anomalies had absence of the left artery, p = 0.103. Cytogenetic abnormalities were noted in 6 fetuses, all with absence of the left artery, p = 0.181. In fetuses with a single umbilical artery as an isolated finding, small-for-gestational-age fetuses occurred in 4 of 50 (8%) pregnancies. CONCLUSION: In fetuses with a single umbilical artery the left artery is more commonly absent than the right artery. In our series cytogenetic and complex fetal anomalies occurred exclusively in fetuses with absence of the left artery. In contrast to previous reports, the incidence of small-for-gestational-age fetuses does not appear to be increased in cases of an isolated single umbilical artery.

Adolescent↗

PubMed1995

Umbilical artery flow velocity waveforms in monoamniotic twins with cord entanglement.

BACKGROUND: Monoamniotic twins with ultrasonographic evidence of umbilical cord entanglement present a management challenge in the antepartum period. CASES: We report two pregnancies with monoamniotic twins and ultrasonographic evidence of cord entanglement in which longitudinal Doppler flow velocity waveforms of the umbilical and middle cerebral arteries were obtained. A notch in the umbilical artery velocity waveform was noted in one twin member at 33 weeks' gestation and in both twin members of the other pregnancy at 31 weeks' gestation. Worsening of the umbilical artery velocity waveform notch with advancing gestation was noted in one fetus. CONCLUSION: The presence of a notch in the umbilical artery velocity waveform may reflect hemodynamic alterations in the fetal-placental circulation secondary to narrowing of the umbilical vessels involved in cord entanglement. This Doppler finding may be useful in the antepartum management of these pregnancies.

Adult↗