Pregnancy complicated by nasopharyngeal carcinoma.
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Adolescent↗
Biomedical subjects
J Star
Publications and source records attributed to J Star.
Should women with human immunodeficiency virus be delivered by cesarean?
Vertical transmission of human immunodeficiency virus (HIV) accounts for most new pediatric cases in the United States. With the routine use of zidovudine in the antepartum, intrapartum, and postnatal periods, transmission of HIV from mother to infant has decreased significantly during the past 5 years. Most transmission occurs during labor and delivery, so the effect of mode of delivery recently has been investigated. Several studies support cesarean to further reduce infection in newborns. However, those studies are limited by lack of data on concomitant effects of viral load and effects of combined antiretroviral therapy. There also might be increased operative morbidity in this population. Therefore, we suggest caution in establishing cesarean as a standard for delivery of HIV-infected women.
Cesarean Section↗
Temperature distribution produced in brain tissue and other media by a radiofrequency hyperthermia generator.
The temperature distribution produced in living brain tissue by a radiofrequency, Neuro N-50, hyperthermia probe was measured as a function of probe temperature, heating duration, and distance from the heating probe by a sensor containing five thermocouples for durations up to 2 min. Brain sections were examined to determine the effects of heating at various temperatures. It was found that a simple theoretical conductive heat transfer model predicted the steady-state temperature distributions quite well. At distances up to 7.4 mm from the heating probe, a heating time of 20 s was sufficient to produce about 90% of the temperature rise measured at 120 s. The equilibrium temperature at any distance from the center of the probe was a linear function of the reciprocal of this distance. The time constant for heating was approximately 3 s at 0. 95 mm from the heating probe and about 10 s at 7.4 mm for brain tissue, while these values are about 5-20 s in egg white. For a given probe size, higher probe temperatures increased the size of the region of cell death. According to the heat transfer model, the diameter of the region of tissue that attains a given temperature is proportional to the diameter of the probe. The use of probe temperatures up to 90 degrees C would enable an increase in the volume of the region of cell death, or the use of a smaller diameter probe to produce a lesion of a given size.
Animals↗
Induced abortion. Physician training and practice patterns.
OBJECTIVE: To examine the relationship between training in induced abortion during residency and subsequent practice patterns in providing abortion services. STUDY DESIGN: An anonymous survey of all obstetrician-gynecologists with admitting privileges at a tertiary care hospital in New England was conducted. Physicians were asked about their residency training experience in performing abortions, current practices and attitudes toward abortion. RESULTS: Ninety-two of 110 physicians (84%) completed the questionnaire. Six physicians who received training after residency and two with incomplete information were excluded from the analysis. Forty-four respondents received training specifically in first-trimester abortion, and 42 did not. Physicians who received training were more likely to provide abortion services (49% vs. 21%, P = .01), to ask patients about their plans for continuing pregnancy (65% vs. 41%, P = .007) and to support medical assistance funding for abortion (84% vs. 45%, P = .001) than were physicians who did not receive training during residency. Beliefs were significantly associated with current practice, even after controlling for differences in residency training in abortion. CONCLUSION: Differences in practice patterns exist between physicians who receive abortion training and those who do not. Practice patterns are associated with beliefs even after controlling for variations in training.
Abortion, Induced↗
The effect of pregnancy on the natural history of diabetic retinopathy and nephropathy.
Retinopathy and nephropathy are complications of diabetes mellitus that can affect women of reproductive age. This article focuses on the effect of pregnancy on the risk of progression of microvascular disease, both during gestation and at long-term follow-up. Fortunately, with intensive medical surveillance and appropriate interventions, most women with types 1 and 2 diabetes mellitus can be offered an optimistic prognosis for child bearing.
Diabetes Mellitus, Type 1↗
Flow cytometric analysis of platelet activation throughout normal gestation.
OBJECTIVE: To measure platelet activation in normal pregnancy, before and after stimulation with agonists, with a whole blood flow cytometric technique. METHODS: In a cross-sectional study, 5 mL of whole blood was collected from healthy volunteers (nine in the first trimester, ten in the second trimester, 35 in the third trimester, and 32 nonpregnant controls). Platelets were treated with an agonist (thrombin or U-46619, a thromboxane A2 analogue) or buffer and were exposed to saturating concentrations of monoclonal antibodies directed against platelet membrane glycoproteins (GPs): 7E3 (fibrinogen receptor GPIIb/IIIa), S12 (alpha granule marker P-selectin), and 6D1 (von Willebrand factor receptor GPIb). Mean fluorescence intensity was determined for 5000 platelets per sample by using a flow cytometer. RESULTS: In the absence of agonist, no significant difference between groups was found in antibody binding. At no stage of pregnancy were circulating activated platelets detected. Platelets from third-trimester subjects bound significantly less 7E3 than platelets of controls or of first- or second-trimester subjects after stimulation with high-dose thrombin (P < .05 for all comparisons). Down-regulation of 6D1 on platelets after stimulation with high-dose U-46619 was significantly greater in third-trimester gravidas than in controls or first-trimester subjects (P < .05). CONCLUSION: Pregnancy does not increase the percentage of activated platelets in the circulation. Platelet reactivity is altered in the third trimester, as evidenced by decreased antibody binding to fibrinogen receptor epitope and enhanced down-regulation of a von Willebrand factor receptor epitope.
15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗
The relationship between second-trimester amniotic fluid insulin and glucose levels and subsequent gestational diabetes.
Associations between elevated amniotic fluid glucose and insulin levels in the second trimester and the subsequent development of gestational diabetes have been reported. We conducted a case-control study to determine which analyte best predicts future maternal glucose intolerance. Thirty-nine women diagnosed with gestational diabetes (criteria of Carpenter and Coustan, Am. J. Obstet. Gynecol., 144, 768, 1982) who had undergone genetic amniocentesis for advanced maternal age were matched with euglycaemic controls. Glucose and insulin concentrations were determined by analysis of stored amniotic fluid samples. No significant difference was detected between cases and controls for amniotic fluid glucose concentrations. Amniotic fluid insulin concentrations were significantly higher in cases (mean rank 4.44, P < 0.01, using matched rank analysis of variance, where 1 is the lowest and 6 is the highest rank). After conversion to multiples of the median, 20 per cent of women with subsequent gestational diabetes were found to have amniotic fluid glucose levels at or above the 90th centile, while 35 per cent of cases had similarly elevated amniotic fluid insulin levels. We conclude that second-trimester amniotic fluid insulin is a more sensitive predictor of impending glucose intolerance than amniotic fluid glucose, although neither is sufficiently powerful to use alone as a screening test.
Adult↗
Fetal hyperinsulinism at 14-20 weeks and subsequent gestational diabetes.
OBJECTIVE: To examine the predictive value of amniotic fluid (AF) insulin at 14-20 weeks' gestation for subsequent gestational diabetes and macrosomia in unselected gravidas 35 years or older at time of genetic amniocentesis. METHODS: We identified 296 pregnancies through stored AF samples from genetic amniocenteses (collected March 1987 through August 1992) in women meeting the following criteria: age 35 years or older, amniocentesis at 14-20 weeks, performance of a 50-g glucose challenge test, and adequate delivery data. RESULTS: A modified double-antibody radioimmunoassay reliably measured AF insulin with a detection limit of 0.35 microU/mL. Pregnant women in whom gestational diabetes was later diagnosed had higher median AF insulin levels than women who did not (0.60 versus 0.42 microU/mL, respectively; P = .026). A stepwise logistic regression analysis of gestational age at amniocentesis, maternal second-trimester weight, maternal age, and log AF insulin value on gestational diabetes showed only AF insulin to have a significant association with gestational diabetes (P = .004). Seven of 21 cases of gestational diabetes had AF insulin values exceeding the 95th percentile (1.33 microU/mL) compared with only 14 of 275 women with normal glucose tolerance (P < .001). Amniotic fluid insulin did not predict macrosomia in either nondiabetic or gestational diabetic pregnancies. CONCLUSION: Gestational diabetes is associated with increased AF insulin at 14-20 weeks, suggesting augmentation of fetal insulin production in the early fetal period in at least some cases of gestational diabetes.
Adult↗
Intrauterine therapy for homozygous alpha-thalassemia.
BACKGROUND: Alpha-thalassemia is one of the most common genetic disorders in the world and is becoming more common in the United States with the increase in immigration of susceptible populations. This disease has been stated previously to be incompatible with extrauterine life. CASE: A Filipino woman with a prior loss due to hemoglobin Bart's underwent prenatal diagnosis that confirmed recurrence in the index pregnancy. Intravascular intrauterine exchange transfusions maintained appropriate fetal growth. A cesarean delivery yielded a 2190-g male infant with minor malformations. The postnatal course was characterized by mild respiratory insufficiency. Postnatal chronic transfusion therapy is underway pending consideration for bone marrow transplantation. CONCLUSION: Antenatal diagnosis and therapy of homozygous alpha-thalassemia can prevent the prenatal consequences of hydrops and fetal death. New technologies such as stem cell transplantation may help to avert both prenatal and postnatal consequences.
Abnormalities, Multiple↗
Glucocorticoid-associated maternal hyperglycemia: a randomized trial of insulin prophylaxis.
OBJECTIVES: To study the degree and timing of maternal hyperglycemia following betamethasone therapy in nondiabetic patients and establish a prophylactic dose of insulin. METHODS: Forty-five patients receiving betamethasone 12 mg i.m. at 7 AM on two consecutive days were randomized to no insulin (n = 20), low-dose insulin (n = 18), and high-dose insulin (n = 7) protocols. Each treatment group received s.c. insulin at 7 AM on the 2 days of betamethasone therapy (20 units NPH/10 units regular, and 40 units NPH/20 units regular, respectively). Capillary plasma glucose measurements were obtained at fasting and 2 h after meals for 3 days. A multivariate normal regression model was used to estimate and compare mean glucose levels. RESULTS: Eighty-five percent of patients who did not receive insulin exhibited hyperglycemia at levels previously associated with fetal acidosis. Significant differences in mean postprandial plasma glucose levels were found between the no-treatment and insulin groups on days 1 and 2. No significant differences were noted between groups on day 3. CONCLUSIONS: Transient maternal hyperglycemia occurs in a consistent pattern in nondiabetic patients receiving betamethasone, which can be limited by the concurrent use of insulin. Further studies to assess fetal acidosis in this setting are warranted.
Adult↗
A normative study of obstetric complications associated with fetal trisomy 18.
Our objective was to determine whether the cesarean section rate and amniotic fluid lecithin-sphingomyelin ratio (L/S ratio) associated with fetal trisomy 18 are different from those associated with euploid pregnancies. Forty-nine trisomy 18 pregnancies were identified and their records were reviewed. Of the 22 live-born infants, 15 (68%) were delivered by cesarean section. The overall cesarean section rate for the institution ranged from 19.1% to 22.6%. In five patients with gestational ages between 35 and 38 weeks who had amniocentesis as part of the evaluation of intrauterine growth retardation, the L/S ratios were < or = 1.8. These data confirm that undiagnosed trisomy 18 pregnancies are associated with an increased cesarean section rate. Further, trisomy 18 fetuses appear to have delayed maturation of the L/S ratio. These results reinforce the importance of a karyotypic evaluation of selected pregnancies complicated by intrauterine growth retardation, even in the third trimester, and suggest that the prenatal diagnosis of trisomy 18 is of obstetric importance.
Amniocentesis↗