Biomedical subjects

W L Leaphart

Publications and source records attributed to W L Leaphart.

4 recordsLinked to original sources

PubMed1998

Adenosine diphosphate-induced platelet activation inhibited by magnesium in a dose-dependent manner.

OBJECTIVE: To examine the hypothesis that magnesium inhibits platelet activation at concentrations equivalent to therapeutic levels. METHODS: Fifteen subjects were enrolled: five healthy, female donors with regular, spontaneous menstrual cycles; five women with uncomplicated third-trimester pregnancies; and five preeclamptic subjects before magnesium therapy. Anticoagulated whole blood was added to tubes containing 0.5 micromol/L adenosine diphosphate (to activate platelets), HP1-1D (activation-independent platelet antibody), CD62 antibody and CD63 antibody (activation-dependent platelet antibodies), and magnesium sulfate in increasing concentrations (2-100 mg/dL). The percentage of activated platelets (CD62 or CD63 positive) was determined using three-color flow cytometric analysis. Data were analyzed using the Student t test, repeated measures analysis of variance, two-way analysis of variance, and Student-Newman-Keuls for pairwise comparison in appropriate cases. P < .05 was considered significant. RESULTS: Adenosine diphosphate-induced platelet activation was inhibited with increasing magnesium concentration in all subjects (P < .001). Significant inhibition of CD62 and CD63 expression first occurred at a magnesium concentration of 4 mg/dL in the normal pregnant group (P < .05), at 6 mg/dL in the preeclamptic group (P < .05), and at 8 mg/dL in the nonpregnant group (P < .05). CONCLUSION: Magnesium inhibits adenosine diphosphate-induced platelet activation in a dose-dependent manner. This effect initially attains statistical significance at concentrations equivalent to therapeutic levels.

Adenosine Diphosphate↗

PubMed1997

Placenta previa percreta with bladder invasion.

BACKGROUND: Although the clinical presentation and imaging techniques can raise suspicion for placenta previa percreta, this potentially catastrophic condition may remain undiagnosed or its extent underappreciated until delivery. The decision to proceed with definitive surgery in cases of placenta previa percreta should be carefully considered. CASE: A case of placenta previa percreta with bladder invasion was diagnosed prenatally. This case illustrates the magnitude of complications that can arise despite aggressive multidisciplinary perioperative management. CONCLUSION: When possible, hysterectomy performed for placenta previa percreta is best avoided under anything other than ideal conditions. A multidisciplinary approach for preoperative, intraoperative, and postoperative management of placenta previa percreta optimizes maternal outcome.

Adult↗

PubMed1996

Hysterotomy to effect vaginal delivery with mentum anterior head entrapment.

BACKGROUND: Entrapment of the aftercoming head after mentum anterior rotation is a life-threatening complication of vaginal breech delivery. Few options exist when rotation and flexion from this position cannot be performed successfully either transabdominally or with vaginal maneuvers. CASE: A term primigravida presented with a singleton breech in advanced labor. The fetal torso and arms delivered vaginally, but the aftercoming head became extended and was entrapped in a mentum anterior position. The fetal head could not be rotated and flexed, either vaginally or transabdominally with suprapubic pressure. Laparotomy and hysterotomy were performed, and vaginal delivery of a live fetus was accomplished after rotation and flexion of the fetal head through this incision. CONCLUSION: Hysterotomy is a safe and effective maneuver for delivery of the entrapped fetal head with mentum anterior rotation after standard procedures have failed.

Adolescent↗

PubMedDate not supplied

Labor induction with a prenatal diagnosis of fetal macrosomia.

Since our institution has a low cesarean rate (14%), it was our hypothesis that the rate of cesarean delivery in patients who underwent induction for macrosomia would be similar to the cesarean rate in patients with similar birth weights who entered labor spontaneously. A retrospective analysis of cases seen from December 1993 to July 1995 revealed 53 nondiabetic patients who underwent induction for fetal macrosomia. These study patients were matched to the next nondiabetic patient delivering a child of equal or greater birth weight who entered labor spontaneously. Maternal demographics, labor characteristics, and neonatal outcome data were reviewed. There were no differences between the induction and spontaneous labor groups in maternal age, gestational age, rate of nulliparity, incidence of shoulder dystocia, Apgar scores, or vaginal birth after prior cesarean delivery. The cesarean delivery rate was higher in the induction group when compared to the spontaneous labor group (36% vs. 17%, P < 0.05) despite a lower birth weight in the induction group (4,102 +/- 374 g vs. 349 g, P < 0.05). Regional analgesia was administered more frequently in the induction group (38% vs. 53%, P < 0.05). An increased risk of cesarean delivery was observed in subjects undergoing induction for the indication of fetal macrosomia. These data support a plan of expectant management when fetal macrosomia is suspected.

Analgesia↗