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Featured researches published by Lawrence Nathan.


Obstetrics & Gynecology | 1994

Correlation of Measured Amniotic Fluid Volume and Sonographic Predictions of Oligohydramnios

Robyn Horsager; Lawrence Nathan; Kenneth J. Leveno

Objective: To compare the measured volume of amniotic fluid (AF) in term gestations to the volume predicted sonographically. Methods: One hour before elective cesarean delivery, 40 women had sonographic measurement of the AF index and largest vertical pocket diameter. At surgery, a suction catheter was placed into a 1‐cm uterine incision and a second catheter was used to aspirate AF from the operative field. Hemoglobin concentration was measured in the collected AF to determine the extent of blood contamination. Results: The mean measured AF volume was 532 mL (range 40‐1692). The correlation cofficient between AF index and AF volume was 0.744 (P < .001). A similar value (r = 0.755, P < .001) was observed for the largest vertical pocket measured with ultrasound. Conclusion: Sonographic measurements of the largest vertical pocket and the AF index have similar positive correlations with measured AF volumes at term. Current methods of estimating AF volume have low sensitivity for detecting oligohydramnios. (Obstet Gynecol 1994;83: 955‐8)


American Journal of Obstetrics and Gynecology | 1993

The return of life-threatening puerperal sepsis caused by group A streptococci

Lawrence Nathan; Mark T. Peters; Annelle M. Ahmed; Kenneth J. Leveno

A dramatic decline in the prevalence of serious puerperal infection caused by group A beta-hemolytic streptococci has been observed throughout most of the twentieth century, and it is currently a very uncommon cause of maternal morbidity and mortality. We report on two term pregnancies complicated by profound multisystem organ failure caused by group A streptococcal puerperal sepsis. This report serves to highlight the apparent return of serious group A streptococcal puerperal sepsis and to emphasize the clinical implications and sequelae attributable to an old yet virulent enemy.


American Journal of Obstetrics and Gynecology | 2000

Correlation between amniotic fluid glucose concentration and amniotic fluid volume in pregnancy complicated by diabetes

Jodi S. Dashe; Lawrence Nathan; Donald D. McIntire; Kenneth J. Leveno

OBJECTIVE Pregnancies complicated by diabetes are frequently characterized by an increased volume of amniotic fluid, and the pathophysiologic mechanism of this increase is not known. Our goal was to evaluate the relationship between amniotic fluid glucose concentration and the amniotic fluid index in pregnancies complicated by insulin-treated diabetes and to compare it with that seen in normal pregnancies. STUDY DESIGN Amniotic fluid index and amniotic fluid glucose levels were measured before elective repeated cesarean delivery in 41 women with insulin-treated diabetes and in 35 women without diabetes. Only singleton gestations without anomalous fetuses were included. Women with diabetes were hospitalized for approximately 4 weeks before delivery, during which time glycemic control was optimized. Amniotic fluid index and amniotic fluid glucose concentration were correlated with each other and were compared between the groups with and without diabetes. RESULTS The mean amniotic fluid index was significantly increased in the diabetes group (16.6 +/- 5.0 cm in the diabetes group vs 13.4 +/- 3.5 cm in the control group; P =.002). The amniotic fluid glucose concentration was also significantly greater in the diabetes group than in the control group (39 +/- 17 mg/dL in the diabetes group vs 24 +/- 11 mg/dL in the control group; P <.001). Among women with diabetes the amniotic fluid glucose concentration was significantly correlated with the amniotic fluid index (r = 0.32; P =.04), a correlation not found among the control women. The mean fasting blood glucose concentration among the women with diabetes for the week before amniocentesis was 82 +/- 11 mg/dL. CONCLUSION The amniotic fluid index parallels the amniotic fluid glucose level among women with diabetes. This finding raises the possibility that the hydramnios associated with diabetes is a result of increased amniotic fluid glucose concentration.


Journal of Ultrasound in Medicine | 1993

Fetal syphilis: correlation of sonographic findings and rabbit infectivity testing of amniotic fluid.

Lawrence Nathan; Diane M. Twickler; Mark T. Peters; Pablo J. Sánchez; George D. Wendel

Fetal syphilis is the presumed diagnosis when the sonographic findings of fetal hydrops are found in the presence of maternal syphilis. In the absence of fetal hydrops, the diagnosis of fetal infection is difficult. We hypothesized that intra‐amniotic infection would be accompanied by anatomic placental and fetal abnormalities that could be detected by ultrasonography. Rabbit infectivity testing (RIT), intratesticular inoculation of rabbits with amniotic fluid, can be used to confirm intra‐amniotic infection with Treponema pallidum. Twenty‐one gravidas with untreated early (primary, secondary, and early latent) syphilis underwent sonography and amniocentesis for RIT at 24 weeks of gestation or later. Antenatal sonographic findings were compared to their amniotic fluid RIT results. Hepatomegaly was significantly (P < 0.01) associated with amniotic fluid infection detected by RIT. Antenatal detection of hepatomegaly, which is probably the initial sonographic manifestation of hydrops fetalis, may ultimately identify the fetus affected with congenital syphilis.


Infectious Diseases in Obstetrics & Gynecology | 1994

Group A Streptococcal Puerperal Sepsis: Historical Review and 1990s Resurgence

Lawrence Nathan; Kenneth J. Leveno

There appears to be a resurgence of puerperal sepsis due to a historically important pathogen, group A β-hemolytic streptococcus.


Infectious Diseases in Obstetrics & Gynecology | 1995

Chlamydia trachomatis: Management in Pregnancy

Alex Allaire; Lawrence Nathan; Mark G. Martens

Chlamydia trachomatis is a sexually transmitted disease (STD) commonly diagnosed in pregnancy. C. trachomatis has been linked to several pregnancy complications including premature rupture of membranes (PROM), preterm labor and birth, low birth weight, intrauterine growth retardation, and postpartum endometritis. Infants born to mothers through an infected birth canal are at risk for acquiring C. trachomatis pneumonitis, conjunctivitis, and nasopharyngeal infection. The standard treatment of C. trachomatis in pregnancy is erythromycin. Recently, amoxicillin and clindamycin have been added as alternative regimens for those patients intolerant of erythromycin. This paper reviews the effectiveness and tolerance of the alternative regimens compared with erythromycin and the success of antepartum treatment of chlamydia in preventing the poor pregnancy outcome and neonatal morbidity associated with C. trachomatis.


Obstetrical & Gynecological Survey | 1993

Fetal syphilis: Correlation of sonographic findings and rabbit infectivity testing of amniotic fluid

Lawrence Nathan; Diane M. Twickler; Mark T. Peters; Pablo J. Sánchez; George D. Wendel

Fetal syphilis is the presumed diagnosis when the sonographic findings of fetal hydrops are found in the presence of maternal syphilis. In the absence of fetal hydrops, the diagnosis of fetal infection is difficult. We hypothesized that intra-amniotic infection would be accompanied by anatomic placental and fetal abnormalities that could be detected by ultrasonography. Rabbit infectivity testing (RIT), intratesticular inoculation of rabbits with amniotic fluid, can be used to confirm intra-amniotic infection with Treponema pallidum. Twenty-one gravidas with untreated early (primary, secondary, and early latent) syphilis underwent sonography and amniocentesis for RIT at 24 weeks of gestation or later. Antenatal sonographic findings were compared to their amniotic fluid RIT results. Hepatomegaly was significantly (P < 0.01) associated with amniotic fluid infection detected by RIT. Antenatal detection of hepatomegaly, which is probably the initial sonographic manifestation of hydrops fetalis, may ultimately identify the fetus affected with congenital syphilis.


Prenatal Diagnosis | 1997

In utero infection with Treponema pallidum in early pregnancy

Lawrence Nathan; Van R. Bohman; Pablo J. Sánchez; N. Kristine Leos; Diane M. Twickler; George D. Wendel


Obstetrics & Gynecology | 1993

Penicillin levels following the administration of benzathine penicillin G in pregnancy

Lawrence Nathan; Roger E. Bawdon; Sidawi Je; Stettler Rw; McIntire Dm; George D. Wendel


Journal of Reproductive Medicine for the Obstetrician and Gynecologist | 1995

Cerebellar hemangioblastoma complicating pregnancy

Lawrence Nathan; Andrew J. Satin; Diane M. Twickler

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Diane M. Twickler

University of Texas Southwestern Medical Center

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George D. Wendel

University of Texas Southwestern Medical Center

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Kenneth J. Leveno

University of Texas Southwestern Medical Center

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Pablo J. Sánchez

University of Texas Southwestern Medical Center

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N. Kristine Leos

University of Texas Southwestern Medical Center

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Van R. Bohman

University of Texas Southwestern Medical Center

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Andrew J. Satin

Uniformed Services University of the Health Sciences

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Annelle M. Ahmed

University of Texas Southwestern Medical Center

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Donald D. McIntire

University of Texas Southwestern Medical Center

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