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Biomedical subjects

L Leduc

Publications and source records attributed to L Leduc.

11 recordsLinked to original sources
PubMed1992

Successful treatment with the Smith-Hodge pessary of cervical incompetence due to defective connective tissue in Ehlers-Danlos syndrome.

Ehlers-Danlos syndrome (EDS) is a heterogeneous group of inherited connective tissue disorders with at least ten distinct types. We report a case of EDS complicated by cervical incompetence. Treatment was undertaken after confirmation that the patient's EDS was not type IV, hence not associated with potentially serious vascular complications. Because of concern about stretching or tearing of the hyperextensible connective tissue associated with EDS, cerclage was not performed. The cervical incompetence due to defective connective tissue was treated with a Smith-Hodge pessary.

Adult↗
PubMed1992

Coagulation profile in severe preeclampsia.

One hundred women with severe preeclampsia or chronic hypertension with superimposed preeclampsia were seen during a 2-year period. We sought to determine whether a normal platelet count assures that no other clinically significant clotting abnormalities are present, and what level of thrombocytopenia predicts a risk of abnormalities in other coagulation indices. Fifty women had platelet counts below 150,000/microL, of whom 13 had a fibrinogen level below 300 mg/dL and two had a prolonged prothrombin time (PT) or partial thromboplastin time (PTT). The admission platelet count was an excellent predictor of subsequent thrombocytopenia (r = 0.829, P less than .001). No subject had an abnormal fibrinogen level or prolonged PT or PTT in the absence of thrombocytopenia. When monitoring intrapartum coagulation indices in preeclampsia, one can safely follow only the platelet count at admission and subsequently, reserving PT and PTT and fibrinogen levels for those cases complicated by counts less than 100,000/microL.

Adult↗
PubMed1991

Baroreflex function in normal pregnancy.

The sinoaortic baroreflex is one of the primary mechanisms that regulates blood pressure. Decreased baroreflex sensitivity has been reported in preeclampsia. We sought to determine whether pregnancy altered baroreflex sensitivity. From a radial artery catheter, heart rate and mean arterial pressure were recorded continuously onto a polygraph. The ratio of change in heart rate produced per unit of change in mean arterial pressure was calculated as an index of baroreflex sensitivity. Mean arterial pressure responses to incremental infusions of phenylephrine (0.4 to 2.0 micrograms/kg/min) were measured in the same patients at term (n = 9, 38.0 +/- 0.3 weeks) and again 6 to 8 weeks postpartum (n = 7). The results indicated (1) higher baroreflex sensitivity in pregnancy than in the postpartum period (0.9 vs 0.5 beats/min/mm Hg) (p less than 0.007); (2) attenuated vascular responsiveness to alpha-adrenergic stimulation in pregnancy (p less than 0.05); (3) a relationship between vascular responsiveness and baroreflex sensitivity. We conclude that pregnancy is associated with an increase in baroreflex sensitivity and that the attenuated response to phenylephrine is, at least in part, a result of increased baroreflex sensitivity.

Adolescent↗
PubMed1991

The hemodynamic effects of intubation during nitroglycerin infusion in severe preeclampsia.

The effectiveness of intravenous nitroglycerin infusion in lowering maternal blood pressure and in blunting the hemodynamic responses to endotracheal intubation was evaluated in six primigravid women with severe preeclampsia. Monitoring consisted of continuous electrocardiogram monitoring, arterial cannulation, and flow-directed pulmonary arterial catheterization in each patient. All patients underwent oxytocin induction of labor and crystalloid and/or colloid expansion to produce a pulmonary capillary wedge pressure of 10 to 15 mm Hg and a colloid osmotic pressure of greater than 17 mm Hg. Intravenous nitroglycerin was administered before induction of general anesthesia. The hemodynamic effects associated with endotracheal intubation revealed a change in the heart rate from 104 +/- 10 to 133 +/- 17 beats/min, an increase in mean arterial pressure from 134 +/- 12 to 164 +/- 32 mm Hg, and an increase in systemic vascular resistance from 1262 +/- 342 to 1351 +/- 259 dynes-sec-cm-5 that was accompanied by a small change in the cardiac index from 4.5 +/- 1.2 to 4.5 +/- 0.9 L.min-1.m-2.

Acute Disease↗
PubMed1991

Urinary sediment changes in severe preeclampsia.

We analyzed the urinary sediment of 30 patients with severe preeclampsia every 4 hours during early labor, delivery, and the postpartum period. Fifteen normal control patients were also followed in a similar fashion. No casts were noticed in the urine samples of the control group. However, the urinary sediment of preeclamptic patients revealed the same uniform pattern regardless of the state of coagulation, or the presence or absence of oliguria or eclamptic seizures. Numerous granular and hyaline casts, red-cell, and tubular cell casts were identified during microscopic evaluation. These data reflect both glomerular and tubular damage in preeclampsia. We conclude that urinary sediment analysis in severe preeclampsia uniformly reflects renal parenchymal damage and does not correlate with or predict the clinical course of the disease.

Adult↗
PubMed1990

Neurokinin inhibition of cholinergic myenteric neurons in canine antrum.

Neurokinins regulate gastrointestinal motility by interacting with receptors on both muscle layers and on myenteric plexus neurons. To determine if specific neurokinin (NK) receptor agonists can mediate inhibitory effects on myenteric neurons, we studied the effect of the NK-1 agonist substance P methylester (SPME) and the putative endogenous NK-2 receptor ligand neurokinin A (NKA) on [3H]acetylcholine [( 3H]ACh) release induced by electrical field stimulation from muscle strips cut from the canine gastric antrum. SPME but not NKA caused a dose-dependent inhibition of stimulated [3H]ACh release in tissues containing the myenteric plexus. The inhibition was not seen in longitudinal muscle without myenteric plexus. Pretreatment of tissues with indomethacin or antiserum to vasoactive intestinal polypeptide (VIP) but not naloxone or adrenergic or cholingergic blockade abolished the SPME-induced inhibition. Exogenous VIP stimulated the release of prostaglandin E2 (PGE2) from full thickness strips, and both VIP and PGE2 inhibited [3H]ACh release induced by electrical depolarization. These findings suggest that NK-1 receptor agonists can selectively inhibit stimulated [3H]ACh release and that this inhibition may involve the release of VIP and PGE2 from neurons within the myenteric plexus.

Acetylcholine↗
PubMed1990

Fetoplacental blood volume estimation in pregnancies with Rh alloimmunization.

Direct intravascular fetal transfusion under ultrasound guidance has become an important method of treating fetal anemia secondary to maternal red cell alloimmunization. An estimate of normal circulating volume would be useful in selecting the volume of donor blood to be transfused to achieve a desired final hematocrit. Thirty-five fetuses between 21 and 35 weeks of gestation underwent 67 direct intravascular transfusions. The fetoplacental volume relative to fetal weight estimated by ultrasound was found to be relatively constant throughout gestation at approximately 100 cm3/kg. The severity of fetal hemolytic disease and its treatment with intrauterine transfusions did not appear to alter the fetoplacental volume. A nomogram for fetoplacental blood volume versus gestational age is described.

Blood Transfusion, Intrauterine↗
PubMed1990

Intrathecal morphine analgesia and low-dose dopamine for oliguria in severe maternal pulmonary hypertension. A case report.

Maternal pulmonary hypertension can be life threatening, and many problems and complications can occur during labor and delivery as well as postpartum. A case of severe maternal pulmonary hypertension was monitored with a pulmonary artery catheter. Intrathecal morphine was administered for labor analgesia, and low-dose dopamine was utilized for maternal oliguria. Neither the morphine nor the dopamine resulted in adverse maternal hemodynamic effects. Both analgesia and resolution of the oliguria were accomplished.

Adult↗
PubMed1989

Ultrasonographic guidance for central venous access during pregnancy.

Real-time ultrasonographic imaging of vascular and anatomic neck structures allows easy visualization of the right internal jugular vein and carotid artery. Application of this technology during pregnancy may reduce potential complications encountered with central venous monitoring and will be especially useful in cases of difficult anatomy.

Adult↗
PubMedDate not supplied

[The pertinence of microscopic analysis of the urine as a diagnostic test for asymptomatic bacteriuria in pregnancy].

The genito-urinary tract is the most frequent site of infection during pregnancy. Asymptomatic bacteriuria is found in 2 to 12% of the obstetrical population. The importance of its detection is underlined by the fact that 20 to 40% of untreated cases will present acute pyelonephritis. Our study's first aim was determining the incidence of asymptomatic bacteriuria in our population. Our results show an incidence of 3.9%. Second, routine mandatory prenatal laboratory examinations include urinalysis and urine culture. Considering the fact that we already do a routine culture, we questioned the pertinence of the microscopic part of urinalysis for screening asymptomatic bacteriuria. Our study has shown that no amount of erythrocytes, leucocytes, bacteria, pus or combination thereof has sufficient sensitivity and/or specificity to be used for screening. We thus conclude that in our context of budget restrictions, the microscopic analysis of urine should be abandoned as a routine test. The biochemical part of urinalysis could be done easily with dipsticks at a lower cost. Urine culture remains the gold standard for detection of asymptomatic bacteriuria.

Adult↗