Novel HLA-G-binding leukocyte immunoglobulin-like receptor (LILR) expression patterns in human placentas and umbilical cords.

Human placentas are sources of cytokines, hormones and other substances that program receptive cells. One of these substances is HLA-G, which influences the functioning of both leukocytes and endothelial cells. In this study, we investigated the possibility that these and/or other types of cells in extraembryonic fetal tissues might respond to HLA-G by interacting with one or another of the leukocyte immunoglobulin-like receptors (LILR). LILRB1 is expressed by most leukocytes and LILRB2 is expressed primarily by monocytes, macrophages and dendritic cells. Analysis of term placentas by immunohistochemistry and Real Time PCR demonstrated that LILRB1 and LILRB2 protein and specific messages are produced in the mesenchyme of term villous placenta but are differently localized. LILRB1 was abundant in stromal cells and LILRB2 was prominent perivascularly. Neither receptor was identified in trophoblast. Further investigation using double label immunofluorescence indicated that placental vascular smooth muscle but not endothelia exhibit LILRB2. Term umbilical cord exhibited the same LILRB2 patterns as term placenta. Samples obtained by laser capture dissection of vascular smooth muscle in umbilical cords demonstrated LILRB2 mRNA, and double label immunofluorescence showed that cord vascular smooth muscle but not endothelium exhibited LILRB2 protein. The presence of LILRB1 in placental stromal cells and LILRB2 in vascular smooth muscle strongly suggest that HLA-G has novel functions in these tissues that could include regulation of placental immunity as well as development and function of the extraembryonic vasculature.

Antigen presenting cells and HLA-G--a review.

Maternal antigen presenting cells, which are macrophages and dendritic cells, are scattered throughout human decidualized endometrium during all stages of pregnancy. These powerful, multi-functional leukocytes reside in close proximity to uterine glandular epithelium, uterine blood vessels, and HLA-G-producing invasive cytotrophoblast cells. Macrophages and dendritic cells, which express the HLA-G receptors, ILT2 and ILT4, play major roles in driving innate and adaptive immune responses, altering the behavior of local stromal cells, shaping the cytokine microenvironment, and protecting the tissue from infection. Therefore, encounters between decidual antigen presenting cells and HLA-G molecules are likely to influence uterine and placental homeostasis as well as local maternal immune responses to the fetus during pregnancy.

Red blood cell volume in preterm neonates.

In the high-risk neonate, the direct determination of the red cell volume by radionuclide dilution technique appears to be the singularly definitive method of defining treatment efficacy, and is thus a useful evaluation and management tool for the pediatrician. For effective patient management, the red blood cell(RBC) volume of 69 preterm and term neonates was determined. The method utilized, Tc-99m-labeled RBCs, provided a fast and accurate answer with a large reduction in the absorbed radiation dose. In the population studied within a high-risk newborn ICU, the mean RBC volumes between the preterm and term neonates were without significant difference. Grouping and analysis of the RBC volume data with respect to birth weight, gestational ages, and 1- and 5-minute Apgar scores revealed on statistical difference. The mean value found in our population, 32.2 +/- 9.2 ml/kg, however, does differ from those previously reported in which the determinations were made using an indirect estimation from the plasma compartment.

In vitro studies of cell-mediated immunity to Moloney murine leukemia virus and Moloney leukemia-associated surface antigens.

Cell-mediated immunity to Moloney murine leukemia virus (M-MuLV) and to tumor-associated surface antigens of leukemia cells induced by the virus was studied with an in vitro migration inhibition factor assay. Spleen cells of C57BL/6N mice at Day 14 following inoculation with Moloney murine sarcoma virus, produced migration inhibition factor in response to M-MuLV. The Moloney murine sarcoma virus-immune spleen cells, however, did not respond to other murine type C viruses, to AKR and Rauscher viruses, or to murine mammary tumor virus. The immune spleen cells also responded specifically to purified glycoprotein with molecular weights of 69,000 and 71,000 and proteins with molecular weights of 30,000 and 12,000, but not to protein with a molecular weight of 10,000, of the homologous M-MuLV. Migration inhibition factor production was also observed in response to soluble 3 M KCl extracts of leukemia cells, MBL-2, induced by M-MuLV. Similarly, the immune spleen cells responded to membrane fractions purified from the MBL-2 cells. Comparable membrane fractions prepared from a Gross virus-induced leukemia, E male G2, and a radiation-induced leukemia, RL male 1, were not active. The tumor-associated surface antigens of MBL-2 membranes could be solubilized by the detergent, Nonident P-40. Thus, C57BL/6N mice inoculated with Moloney murine sarcoma virus developed cell-mediated immunity to envelope and some internal antigens of M-MuLV and also to tumor-associated surface antigens of a tumor induced by this leukemia virus.

Evaluation of human chorionic gonadotropin and alpha fetoprotein in benign and malignant testicular disorders.

The marker proteins alpha fetoprotein and human chorionic gonadotropin are useful adjuncts to clinical evaluation of patients with non-seminomatous testicular germ cell malignant growths during and after therapeutic interventions. Measuring both markers is better than measuring either one alone. An elevated marker assay indicates the presence of active disease. A normal marker assay does not exclude active disease being present. Lastly, these markers are of limited usefulness in the evaluation of undiagnosed testicular masses.

Effects of carbon monoxide on fixed-consecutive-number performance in rats.

Four rats were trained under a fixed-consecutive-number (FCN) schedule to make sequences of 20 or more consecutive responses on one lever followed by a single response on a second lever. When performance was stable, they were exposed to 200, 400, and 600 parts-per-million (PPM) carbon monoxide (CO) for either 30 or 60 min before and during a 45-min session. Decreases in response rate at CO levels as low as 200 ppm were due to both decreased local response rate and extended pauses. A lowered percentage of reinforcement, due to decreases in response sequence length, was also found at CO levels as low as 200 ppm. This decreased sequence length may reflect effects of CO on response rate, or a disruption of discriminative aspects of FCN schedule performance.

Amniotic fluid alpha-fetoprotein as a marker in prenatal diagnosis of neural tube defects.

The prenatal diagnosis of anencephaly and spina bifida (neural tube defect, NTD) through amniotic fluid analysis for alpha-fetoprotein (AFP) is gradually gaining clinical recognition. AFP concentrations were determined in 237 amniotic fluids from normal pregnancies ranging between 7 and 42 weeks of gestation. A steady decline in AFP from 26 mug/ml at 7-9 weeks to 155 ng/ml at term is observed. AFP concentration was determined in 35 amniotic fluids from 33 confirmed neural tube defective pregnancies. In 14 cases where amniotic fluid was examined prior to the 26th week of gestation. AFP was markedly elevated when compared with the normal range of the same gestational period. In 21 amniotic fluids past the 26th week, 17 cases (85-) had markedly elevated AFP levels; however, 2 cases of anencephaly, 1 of spina bifida, and 1 of hydrocephaly gave levels within the normal range. It is concluded that elevated AFP in the amniotic fluid is a reliable but nonspecific marker for open neural tube defects prior to the 26th week of pregnancy, but may become normal after the 26th week in a small percentage of patients.

PIP: A steady decline in alpha fetoprotein (AFP) levels was observed in single specimens of amniotic fluid (AF) from 237 patients, ranging from 26 mcg/ml at 7-9 weeks to 155 ng/ml at term. All pregnancies tested were normal. 35 AF specimens from 33 confirmed neural tube defective pregnancies were assayed for AFP. Very high levels of AFP were found in 13/14 fluids examined before Week 26 of gestation. A value of 23 mcg/ml was determined in 1 sample where the infant had skin-covered encephalocele. A fluid taken from the same patient at 34 weeks fell to 6.4 mcg of AFP. 21 AF samples from patients past the 26th week of pregnancy were analyzed. Of these, 1 case of spina bifida and 2 of anecephaly gave no detectable levels of AFP by electroimmunodiffusion. By radioimmunoassay, however, these samples measured 3700, 256, and 700 ng/ml. 1 case of hydroencephaly, examined at 33 weeks, had an AFP level of 1.5 mcg/ml. A sharp drop in AFP from 353.6 at 15 weeks to 10.4 mcg/ml at 29 weeks was noted in the only serially examined open neural tube defective pregnancy.

Relationship of serum alpha-fetoprotein to the severity and duration of illness in patients with viral hepatitis.

Using a radioimmunoassay which detect concentrations of alpha-fetoprotein as low as 5 ng per ml, 38% of 176 patients with viral hepatitis compared with health volunteers and patients with chronic diseases not affecting the liver. When separated into two groups based on histological classification of liver biopsy specimens, differences in the degree and frequency of increased serum alpha-fetoprotein were related to the severity of the hepatic lesion. Of 75 patients with the lesion of viral subacute hepatic necrosis, in which zones of necrosis bridge adjacent portal triads or central veins, 52% had increased values, and 12% had levels ranging from 500 to 3300 ng per ml. In contrast, only 28% of the 101 patients without bridging necrosis had increased values, and none had levels that exceeded 500 ng per ml. In the patients with subacute hepatic necrosis, comparison of alpha-fetoprotein concentrations with the duration of illness indicated that the protein rose to peak levels in serum as the SGOT was declining. This was confirmed by serial observations in 10 patients. Thus, the increase of alpha-fetoprotein in the sera of patients with severe hepatitis occurs as liver necrosis is subsiding. Due to other known features of alpha-fetoprotein, it is intriguing to speculate that the increase in serum levels of this protein in viral hepatitis reflects hepatic regeneration after parenchymal damage.

Conditioned suppression under positive, negative, and no contingency between conditioned and unconditioned stimuli.

Using a conditioned suppression procedure, the effects of three contingent relationships between conditioned (CS) and unconditioned (US) stimuli were investigated. A traditional positive (if CS-then US) contingency suppressed response rate during the CS relative to responding during stimulus-free minutes of the session. A negative (if CS-then no US) contingency resulted in suppressed responding during CS-off minutes, and rate increases during the CS. A no-contingency control procedure, during which CS and US were randomly related, almost totally suppressed responding throughout the session and showed no differential effects of the CS on response rate. An analysis of changes in response rate during the minute after US-offset revealed acceleration under the no-contingency condition and, to a somewhat lesser degree, under the negative contingency. Both conditioned suppression and non-suppression are analyzed in terms of the temporal relationship between CS and US.