Increased renal parenchymal echogenicity in the fetus: importance and clinical outcome.

Pre- and postnatal ultrasound (US) findings and clinical course in 19 fetuses (16-40 menstrual weeks) with hyperechoic kidneys (renal echogenicity greater than that of liver) and no other abnormalities detected with US were evaluated to determine whether increased renal parenchymal echogenicity in the fetus indicates renal disease. Four infants (21%) were healthy at birth and had normal postnatal sonograms. Another 10 infants (53%) survived, but abnormalities were found at neonatal US.

The generation of immunogenic peptides can be selectively increased or decreased by proteolytic enzyme inhibitors.

The ability of splenic APC and a B cell hybridoma (LS.102.9) to process and present OVA to a panel of T-T hybridomas with different fine specificities was investigated.

Ultrasound detection of fetal aneuploidy in patients with elevated maternal serum alpha-fetoprotein.

Increasing confidence in the ability of high-resolution ultrasound to detect neural tube and ventral wall defects has enabled us to offer a revised risk estimate to the patient with an elevated maternal serum alpha-fetoprotein (MSAFP) level, such that amniocentesis may not be necessary. Recent authors have suggested that a reduced emphasis on follow-up amniocentesis fails to consider an increased risk for chromosomal anomalies in pregnancies with an elevated MSAFP, and that amniocentesis should still be performed. We reviewed our ultrasound findings from patients who underwent amniocentesis for evaluation of an elevated MSAFP and who had a karyotype prepared from the amniotic fluid sample.

Dissociation of beta 2-microglobulin leads to the accumulation of a substantial pool of inactive class I MHC heavy chains on the cell surface.

A large pool of free class I heavy chains is detected in situ on the plasma membrane of living cells. These chains are present on cells of different MHC genotypes and appear to exist under physiological conditions in vivo. These molecules arise from the dissociation of previously assembled class I heterodimers at the cell surface.

Low temperature and peptides favor the formation of class I heterodimers on RMA-S cells at the cell surface.

RMA-S murine cells have a mutation that interferes with the assembly of class I major histocompatibility complex (MHC) heterodimers and are deficient in the expression of class I molecules on the cell surface. The mutant phenotype has been reported to be normalized upon incubation of RMA-S cells at 25 degrees C. We find that much of the increased expression of class I heterodimers is dependent on culturing RMA-S cells in bovine serum or with purified bovine beta 2-microglobulin.

Prenatal diagnosis in diabetic gravidas: utility of ultrasound and maternal serum alpha-fetoprotein screening.

The differences in both the biology of pregnancy and the content of routine care between gravidas with and without diabetes mellitus lead to important differences in the potential utility of both ultrasound examination and maternal serum alpha-fetoprotein (MSAFP) screening. However, both diagnostic methods have become standards of care for these patients, without critical evaluation. This study examines the utility of both ultrasound and MSAFP in diabetic women.

Prenatal diagnosis of lissencephaly.

We report two cases of prenatal detection of lissencephaly by high-resolution ultrasound. The first case studied was referred for high-risk obstetrical management and serial antenatal ultrasounds because of a family history of lissencephaly in an unresolved chromosomal abnormality. Diagnosis of a smooth gyral pattern consistent with lissencephaly was made at 32 weeks' gestation.

Mild fetal lateral cerebral ventriculomegaly: clinical course and outcome.

The neonatal, pathologic outcome and karyotypic abnormalities are reported for 44 fetuses with mild ventriculomegaly diagnosed antenatally. Seventeen of these 44 fetuses (39%) had other ultrasonographic defects, and five (12%) had abnormal karyotypes. Five pregnancies were electively aborted and three other fetuses died in the neonatal period.

Humeral shortening in second-trimester fetuses with Down syndrome.

Individuals with Down syndrome have abnormally short long bones. Sonography has previously revealed slightly shortened femurs and thickened nuchal folds in affected second-trimester fetuses. Humeral and femoral lengths and nuchal folds were evaluated in 400 normal second-trimester controls and in 24 consecutive Down syndrome fetuses (14-20 weeks) undergoing amniocentesis for advanced maternal age or low maternal serum alpha-fetoprotein (MSAFP).

Small sac size in the first trimester: a predictor of poor fetal outcome.

A nonbradycardiac fetal heart rate is associated with a low rate of spontaneous abortion (2%-4%). To determine criteria for predicting impending first-trimester loss when a normal fetal heart rate is identified sonographically, the authors studied 16 consecutively examined patients with pregnancies of 5.5-9 weeks gestation, a small sac size, and fetuses with normal cardiac activity.

Weak base amines can inhibit class I MHC-restricted antigen presentation.

This report describes the effects of NH4Cl, CH3NH2, and chloroquine on class I and II MHC-restricted Ag presentation. OVA-specific T-T hybridomas were used to detect processed OVA in association with class I, H-2Kb, and class II, I-Ad/b, molecules on a B lymphoblastoid APC. OVA, internalized by APC under hypertonic conditions, was presented in association with class I and II MHC molecules.

Reassociation with beta 2-microglobulin is necessary for Db class I major histocompatibility complex binding of an exogenous influenza peptide.

A synthetic peptide corresponding to residues 365-380 of the influenza nucleoprotein (NP365-380) has been previously shown to associate with class I major histocompatibility complex-encoded molecules and to stimulate cytotoxic T lymphocytes [Townsend, A. R. M.

Structural genitourinary defects detected in utero.

Fetal genitourinary anomalies are detected with increasing frequency due to the large numbers of fetuses that undergo screening ultrasonography (US) for nonspecific indications. One hundred seventy-seven patients were evaluated for fetal urinary abnormalities over a 2-year period. Fetal hydronephrosis accounted for 154 (87%) of the cases, with the remaining diagnoses including multicystic dysplastic kidney, autosomal recessive polycystic kidney disease, and renal agenesis or hypodysplasia.

When all is said and done...

Dr. Benacerraf describes his experience in training immunologists for a period of over 30 years. He then analyzes the circumstances in which selected discoveries were made in his laboratory and the events and reasoning that led to these findings.

Fetal abdominal wall defect: a new complication of vesicoamniotic shunting.

Vesicoamniotic shunting for fetal obstructive uropathy is beneficial in selected cases. We report a new complication, fetal abdominal wall defect secondary to vesicoamniotic shunting. Placement of the shunt should be as low and as close to the fetal midline as possible in order to reduce the risk of this complication.

Early amniocentesis: report of 407 cases with neonatal follow-up.

Amniocentesis was performed for prenatal diagnosis in 407 pregnancies between the gestational ages of 11-14 weeks. The safety and accuracy of the procedure were compared with data obtained from collaborative studies of amniocentesis performed later in the second trimester. There were no differences observed with respect to accuracy, pseudomosaicism, or maternal-cell contamination related to the timing of the procedure.

Reassociation with beta 2-microglobulin is necessary for Kb class I major histocompatibility complex binding of exogenous peptides.

T lymphocytes recognize endogenously produced antigenic peptides in association with major histocompatibility complex (MHC)-encoded molecules. Peptides from the extracellular fluid can be displayed in association with class I and class II MHC molecules. Here we report that mature Kb class I MHC molecules bind peptides upon dissociation and reassociation of their light chain.

Absence of need for amniocentesis in patients with elevated levels of maternal serum alpha-fetoprotein and normal ultrasonographic examinations.

Background: Recent improvements in the accuracy of sonographic diagnosis of neural-tube and ventral-wall defects have raised a question about the wisdom of routinely offering amniocentesis to women who have elevated levels of maternal serum alpha-fetoprotein with a structurally normal fetus as determined by ultrasonography.

Methods: We reviewed the ultrasound findings in 51 consecutive fetuses with spina bifida, encephalocele, gastroschisis, or omphalocele that were delivered or aborted at a single hospital, to estimate the sensitivity of ultrasonography for these diagnoses. In all cases, the mothers had undergone prenatal sonography at one facility between 16 and 24 weeks after the last menstrual period.

Hypoplasia of the middle phalanx of the fifth digit. A feature of the second trimester fetus with Down's syndrome.

It has been established that 60% of infants with Down's syndrome have hypoplasia of the middle phalanx of the fifth digit. To determine whether this would be a useful prenatal sonographic sign for Down's syndrome, we measured the middle phalanx of the fifth and fourth digits in 1,032 fetuses between 15 and 20 weeks gestational age at the time of amniocentesis, prior to any knowledge of the karyotypes. A ratio of the middle phalanx of the fifth digit over the middle phalanx of the fourth digit was calculated, and the median ratio for the 1,024 normal fetuses was 0.

Fetal pyelectasis: a possible association with Down syndrome.

Two hundred ten consecutive fetuses were identified as having renal pyelectasis among 7400 patients scanned during 1 year. Seven of these 210 fetuses had Down syndrome. We reviewed images of the kidneys of 44 fetuses with Down syndrome collected over 5 years and found that 25% of these affected fetuses had pyelectasis.

Sonographic accuracy in the diagnosis of ovarian masses.

Prediction of the tissue diagnosis of ovarian masses has remained a challenge for the sonographer since many adnexal masses have nonspecific sonographic appearances. We evaluated the accuracy of the sonographic diagnosis of adnexal masses in 100 women undergoing laparotomy for ovarian masses within eight weeks of an ultrasound study. Comparison of the preoperative sonographic and final pathologic diagnoses revealed a correct sonographic diagnosis in 68% of the cases.

Are choroid plexus cysts an indication for second-trimester amniocentesis?

Previous series that described fetuses with choroid plexus cysts have been too small to determine whether there is an association with trisomy 18 sufficiently high to warrant amniocentesis. To address this issue, we studied the incidence of choroid plexus cysts and other ultrasonographic abnormalities in 26 consecutive fetuses (13.5 to 36 weeks' gestation) with trisomy 18.

Examination of the second-trimester fetus with severe oligohydramnios using transvaginal scanning.

Transvaginal sonographic transducers have permitted better resolution of the pelvic structures than previously possible. The presenting fetal part may be difficult to image transabdominally when lodged deep in the lower uterine segment. In particular, second-trimester fetuses associated with severe oligohydramnios present a challenge to the sonologist because of both the lack of amniotic fluid and the deep and curled fetal position in the maternal pelvis.