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Biomedical subjects

T L Gross

Publications and source records attributed to T L Gross.

At least 55 records · Page 3Linked to original sources
PubMed1984

What affects fetal pulmonary maturation during diabetic pregnancy?

Previous studies differ as to whether the fetus of the woman with diabetes mellitus has altered formation of lung surfactant. The factors responsible for these differences remain unclear. In this study, measures of blood glucose control, including birth weight percentile and the presence of factors potentially influencing fetal pulmonary maturation, such as diabetic class, maternal chronic hypertension, and preeclampsia, were compared with the amniotic fluid lecithin/sphingomyelin ratio, phosphatidylglycerol, and phosphatidylinositol within a group of 90 diabetic pregnancies. The factors were evaluated in combination with the techniques of canonical correlation and multiple regression analysis. Gestational age had the strongest effect in determining levels of amniotic fluid phospholipids, and hypertension was found to significantly accelerate the appearance of phosphatidylgycerol (p less than 0.05). The effect of hypertension was one third as important as that of gestational age. Neither diabetic blood glucose control, White classification, nor the remaining explanatory variables were found to play a significant role in determining the amniotic fluid phospholipid levels. This study suggests that, in the clinical management of diabetes, gestational duration remains the single most important determinant of amniotic fluid phospholipid levels.

Amniotic Fluid↗
PubMed1984

When is an amniocentesis for fetal maturity unnecessary in nondiabetic pregnancies at risk?

For several years standard obstetric practice has been to perform an amniocentesis for evaluation of fetal maturity. In order to provide a more definitive answer as to which pregnancies need an amniocentesis, a group of 294 nondiabetic pregnant women in whom an amniocentesis for the evaluation of fetal maturity had been performed for clinical indications were evaluated. Three predictors of fetal maturity--obstetric estimate of gestational age, fetal biparietal diameter, and ultrasonic determination of placental maturation--were evaluated for their ability to predict three outcomes of fetal maturity, including positive amniotic fluid phosphatidylglycerol, pediatric estimate of gestational age greater than or equal to 38 weeks, and absence of hyaline membrane disease. A fetal biparietal diameter of greater than or equal to 90 mm was present in 36% of the total population and was associated with 97% term delivery, 87% positive amniotic fluid phosphatidylglycerol, and 0% hyaline membrane disease. The results associated with an obstetric estimate of gestational age of greater than or equal to 38 weeks were similar. In the present data set over one third of clinically indicated amniocenteses could potentially be avoided without losing any predictive capability for fetal maturity.

Amniocentesis↗
PubMed1984

Seasonal variation of histomorphologic features of equine endometrium.

The effect of seasonal morphologic variation of equine endometrium on histologic interpretation of periglandular fibrosis was investigated in 5 mares. Endometrial tissue was procured monthly and examined microscopically for the degree of periglandular fibrosis. A prognostic category for each mare was based on the mean number of fibrotic foci per linear field of 5.5 mm. It was found that seasonal changes reflected in endometrial glands and stroma influenced quantitative assessment of fibrosis. This occasionally resulted in a change in the assigned prognostic category. Marked nonseasonal variation in degree of fibrosis was observed in 1 mare, thus indicating that a nonuniform distribution of lesions may influence histologic evaluation of the endometrium.

Animals↗
PubMed1984

The relationship of placental grade, fetal lung maturity, and neonatal outcome in normal and complicated pregnancies.

Ultrasonically diagnosed maturity changes in the placenta, Grades 0 to III, have been previously shown to correlate with fetal lung maturity. In a prospective study of 230 term and preterm complicated pregnancies, we compared the relationship between sonographic placental grading, amniotic fluid phospholipids, and neonatal outcome. The frequencies of gestational age less than 38 weeks, lecithin/sphingomyelin (L/S) ratio less than 2.0, negative phosphatidylglycerol, and neonatal hyaline membrane disease were found to decrease as placental grade advanced from 0 to III. Patients were divided into subgroups on the basis of maternal complications. In patients with Grade III placentas, the frequencies of gestational age less than 38 weeks and L/S ratio less than 2.0 were significantly increased when the subgroup of patients with chronic hypertension was compared individually to both of the subgroups, repeat cesarean section deliveries, and Classes A, B, and C diabetes mellitus (both with p less than 0.05) All three infants who developed hyaline membrane disease in association with Grade III placentas were from pregnancies of less than 38 weeks complicated by chronic hypertension. These findings suggest that the presence of a Grade III placenta is affected by both gestational age and pregnancy complications. Hence, when an elective cesarean section delivery is being planned near term gestation, a Grade III placenta is a reliable predictor of lung maturity. In preterm complicated pregnancies, an ultrasound-diagnosed Grade III placenta may still be associated with hyaline membrane disease.

Amniotic Fluid↗
PubMed1984

Avoiding prematurity in elective repeat cesarean section. A role for amniotic fluid phosphatidylglycerol.

A prospective study was undertaken in 107 elective repeat cesarean deliveries in which the lecithin/sphingomyelin (L/S) ratio was positive. The frequency of neonatal complications in 87 of these women having positive amniotic fluid (AF) phosphatidylglycerol (PG) was compared with the frequency in the remaining 20 patients exhibiting a negative PG. Hyaline membrane disease (HMD) did not occur in either group. However, neonatal complications and related clinical procedures were significantly increased in the PG-negative patients. These neonatal complications included increased frequency of admissions to the neonatal intensive care unit, physiologic jaundice, poor feeding, transient tachypnea, prolonged oxygen therapy, arterial blood gas determinations, chest X-ray and placement of a peripheral intravenous line. The cause of this increased frequency in neonatal complications appears to be mild prematurity in patients exhibiting a positive AF L/S with a negative PG. This study suggests that, in hospitals where PG determinations are available, neonatal complications could be reduced further by awaiting the AF PG result before electively performing a repeat cesarean section.

Amniotic Fluid↗
PubMed1983

Gastroesophageal ulceration and candidiasis in foals.

Gastroesophageal candidiasis in association with ulceration was diagnosed in 5 foals in which signs of colic had been nonresponsive to medical treatment. The ulceration was found in the stomach of all foals and in the esophagus of 1 foal. Candida colonized hyperkeratotic mucosa surrounding the ulcers, and the associated inflammation resulted in splitting of the mucosal epithelium. Loss of the superficial mucosa may have allowed invasion by bacteria, leading to ulceration.

Animals↗
PubMed1983

Transient tachypnea of the newborn: the relationship to preterm delivery and significant neonatal morbidity.

Early studies suggest that transient tachypnea of the newborn is a benign disease of uncertain etiology. Consequently, prevention of this complication has not been a primary concern of obstetricians. In this study of amniotic fluid phospholipids, 55 pregnancies in which the neonate developed transient tachypnea were compared to 355 pregnancies after which respiratory distress did not occur. Thirteen neonatal complications and procedures, often associated with prematurity, were significantly increased in the infants who developed transient tachypnea. Potential risk factors for transient tachypnea were examined by stepwise discriminant analysis. Negative amniotic fluid phosphatidylglycerol, prematurity (less than 38 weeks), and 1-minute Apgar score less than 7 all made an independent contribution to the overall characterization of infants at increased risk for transient tachypnea. These findings suggest that mild fetal lung immaturity may be a factor in the pathophysiology of this syndrome, and that the relationship of perinatal factors associated with transient tachypnea of the newborn in previous studies, including maternal diabetes mellitus and cesarean birth, may be partially mediated through a neonatal surfactant deficiency.

Amniotic Fluid↗
PubMed1983

Detection of intrauterine growth retardation: a new use for sonographic placental grading.

Intrauterine growth retardation (IUGR) is a major source of perinatal death and long-term neurobehavioral morbidity, but its diagnosis antenatally remains difficult. Advanced placental maturity (Grade III), as determined on ultrasound examination, has previously been reported to be a marker of term gestation. In this study of 109 pregnancies which resulted in the birth of infants weighing less than or equal to 2,700 gm, the hypothesis that a Grade III placenta, according to Grannum's classification, can differentiate small-for-gestational age (SGA) infants from small non-SGA infants was tested. Of the study patients, 44 had Grade III placentas and 65 had non-Grade III (0, I, II) placentas within 1 week of delivery. The presence of a Grade III placenta was followed by the delivery of a SGA infant 59% of the time, and 62% of the SGA infants could be correctly identified (p less than 0.001). The association of a Grade III placenta and SGA birth was maintained in patients at less than or equal to 34 weeks of gestation--Grade III placenta was significantly related to the delivery of SGA infants with a true positive rate of 62% and a sensitivity of 66% (p less than 0.008). These results were consistent with the concept that for small fetuses documentation of "maturity" can be used to discriminate those with IUGR from those without this problem. Furthermore, placental "maturation," as detected sonographically, appears to be accelerated in association with IUGR, consistent with the anatomic concept of premature placental senescence. Thus, in situations in which the fetus is known to be small, sonographic grading of the placenta may be helpful in detecting IUGR.

Female↗
PubMed1983

Operative considerations in the obese pregnant patient.

Many obstetricians feel that obesity is associated with a general increase in risks during pregnancy. However, there is some suggestion that obese patients may actually have a decreased risk of premature delivery and delivering small-for-gestational-age infants. Multiple studies have found that even though maternal medical complications are more likely in obese mothers, neonatal outcome can still be excellent in this group. Earlier reports found that the obese mother was at greater risk of abnormal labor and operative delivery. However, recent studies in which nonobese patients have been used as a control group have not found massively obese mothers to be at greater risk of labor abnormalities. Cesarean sections are more common in the overweight mother. The increase in cesarean birth is most likely due to an increase in previous abdominal delivery performed because of increased maternal diabetes and hypertension. Primary cesarean section due to cephalopelvic disproportion does not appear to be increased. When cesarean section is necessary in the massively obese patient, there is clearly an increase in operative morbidity and mortality. The guidelines listed in this article can be instituted best by obstetricians and anesthesiologists experienced in treating massively obese patients. By implementing this special care without undue delay when abdominal delivery is indicated, hopefully maternal and neonatal outcome can be optimized.

Birth Weight↗
PubMed1983

Fetal biparietal diameter an placental grade: predictors of intrauterine growth retardation.

Intrauterine growth retardation (IUGR) is associated with increased fetal and neonatal morbidity and mortality. In a previous study from the authors' laboratory, it was found that a grade 3 placenta on ultrasound examination was helpful in diagnosing the growth-retarded fetus. The present study was designed to evaluate whether this technique would be applicable in clinical practice. In the present study of 191 pregnancies, positive sonographic screening, defined as a fetal biparietal diameter of 87 mm or less, and a grade 3 placenta were found to detect 59% of all growth-retarded fetuses; in addition, half of the identifications of growth-retarded fetuses were correct. Overall risk for IUGR was increased 8.5 times in the presence of a positive sonographic screen--3.5 times for the preterm (less than 38 weeks' gestation) fetus and 18 times for the term fetus. This suggests that information readily available from real-time ultrasound examination--placental maturity grading and biparietal diameter--can improve the detection of IUGR.

Anthropometry↗
PubMed1982

Using ultrasound and amniotic fluid determinations to diagnose intrauterine growth retardation before birth: a clinical model.

Intrauterine growth retardation, a major source of fetal/infant morbidity and mortality, remains difficult to detect reliably before birth. In a previous study from our laboratory, determination of the presence of phosphatidylglycerol (PG) in amniotic fluid was found to be potentially useful for separating the growth-retarded fetus from the appropriately grown fetus of similar size. In the current study, this finding was confirmed and a clinical model for applying this method of detecting the small-for-gestational age (SGA) fetus was developed. Among 249 pregnancies in which ultrasound examination and amniocenteses were performed at or beyond 34 weeks' gestation and within a week of delivery, a fetal biparietal diameter of less than or equal to 87 mm and the presence of PG in amniotic fluid were found to be capable of detecting 80% of all SGA fetuses. Moreover, one half of the predictions of the birth of an SGA infant would have been correct. A positive screen with the use of this model was associated with a fifteen fold increase in risk for the birth of an SGA infant. These findings suggest a series of diagnostic steps to improve the antenatal detection of the growth-retarded fetus. (1) The clinician should assess risks and have a high index of suspicion. (2) When the at-risk pregnancy is thought to be at least 34 weeks, ultrasound examination may be helpful in confirming that the fetus is small. (3) Carefully amniocentesis, with the determination of PG, may then be useful in diagnosing intrauterine growth retardation.

Amniocentesis↗
PubMed1981

Amniotic fluid phosphatidylglycerol: a potentially useful predictor of intrauterine growth retardation.

Intrauterine growth retardation, a major complication of pregnancy, remains difficult to detect reliability prior to birth. In this retrospective study of 82 pregnancies which resulted in birth of small infants, preceding clinical factors and amniotic fluid (AF) maturity tests were examined for their ability to differentiate small for gestational age (SGA) from appropriate for gestational age (AGA) infants of comparable weight. AF maturity tests included phosphatidylglycerol (PG), phosphatidylinositol (PI), lecithin to sphingomyelin ratio (L/S), PG/PI, PG/S, PI/S, foam tests, and fat cell count. Discriminant analysis revealed that AF PG was potentially the most useful parameter for predicting the birth of an SGA infant. The predictive value of PG was related to the strong correlation of AF PG with term gestation. High AF PG could potentially predict SGA infants with a true positive rate of 60%; 64% of all SGA infants could be correctly identified by means of only AF PG. The results of this study suggest that, in selected high-risk pregnancies, amniocentesis late in gestation with determination of PG may be helpful in classifying small infants as either growth retarded or preterm.

Amniotic Fluid↗