Total serum IgD is increased in atopic subjects

We have developed a sandwich-type ELISA system for measuring total IgD levels in the serum of atopics and non-atopic controls. In this ELISA system, affinity purified goat anti-human IgD was used for capture. Results were superior to those obtained with monoclonal anti-human IgD antibody. No cross-reactivity could be demonstrated to IgG, IgM, IgA or IgE. The assay showed minimal non-specific binding even with initial serum dilutions of 1:2. The results obtained were reproducible among replicates (Mean CV +/- SEM = 0.03 +/- 0.002; n = 251), between dilutions (CV = 0.08 +/- 0.006; n = 108), and between assays (CV = 0.05 +/- 0.12; n = 5). We used routine radioimmunoassay for measuring total serum IgE. Using these assays total serum IgD and IgE levels were measured in 75 atopic patients and 33 normal subjects. None of the atopics had recent immunotherapy. As expected, the geometric mean serum IgE in atopics (373 ng/ml) was significantly higher than that in normal subjects (49 ng/ml) (P less than 0.01). However, geometric mean serum IgD was also significantly higher in atopics (20.3 micrograms/ml) than that in normal subjects (8.4 micrograms/ml) (P less than 0.02). In both atopic and normal groups, mean serum IgD level did not differ significantly on the bases of age, sex or asthmatic status. Furthermore, total serum IgD was not significantly correlated with total serum IgE (r = 0.14; P = 0.14; n = 108), indicating that immunoregulatory control of the basal levels of the two isotypes is not linked.(ABSTRACT TRUNCATED AT 250 WORDS)     

Mouse homologues of the human AZF candidate gene RBM are expressed in spermatogonia and spermatids, and map to a Y chromosome deletion interval associated with a high incidence of sperm abnormalities

An RNA-binding motif (RBM) gene family has been identified on the human Y chromosome that maps to the same deletion interval as the 'azoospermia factor' (AZF). We have identified the homologous gene family (Rbm) on the mouse Y with a view to investigating the proposal that this gene family plays a role in spermatogenesis. At least 25 and probably >50 copies of Rbm are present on the mouse Y chromosome short arm located between Sry and the centromere. As in the human, a role in spermatogenesis is indicated by a germ cell-specific pattern of expression in the testis, but there are distinct differences in the pattern of expression between the two species. Mice carrying the deletion Yd1, that maps to the proximal Y short arm, are female due to a position effect resulting in non-expression of Sry ; sex-reversing such mice with an Sry transgene produces males with a high incidence of abnormal sperm, making this the third deletion interval on the mouse Y that affects some aspect of spermatogenesis. Most of the copies of Rbm map to this deletion interval, and the Yd1males have markedly reduced Rbm expression, suggesting that RBM deficiency may be responsible for, or contribute to, the abnormal sperm development. In man, deletion of the functional copies of RBM is associated with meiotic arrest rather than sperm anomalies; however, the different effects of deletion are consistent with the differences in expression between the two species.      

Heart rate reactivity and heart period variability throughout the first year after heart transplantation

Heart rate reactivity to mental stress is substantially blunted early after heart transplantation, suggesting that the loss of neural modulation limits the cardiovascular response to mental stress. We tested whether reactivity to mental stress recovers during the first year after heart transplantation. Hemodynamic and respiratory responses to mental arithmetic challenge were studied in 20 heart transplant recipients 3, 6, and 12 months after surgery. A normal comparison group was studied at equivalent intervals. Heart rate reactivity to mental arithmetic was significantly reduced in the cardiac transplant group compared to the normal subjects. This effect persisted up to 1 year after transplantation. Heart period variability in the heart transplant recipients was minimal in all three-test sessions. The findings suggest that no functional reinnervation or other compensatory adaptation occurs up to 1 year after heart transplantation.     

Studies of Antibody to Herpes Simplex Virus Fcγ-Binding Protein gE in Patients with Rheumatoid Arthritis, Juvenile Rheumatoid Arthritis and Normal Controls

IgG antibody to gE, the Fc gamma-binding herpes simplex 1 (HSV-1) viral glycoprotein, was studied in 49 rheumatoid arthritis (RA) patients and 43 normal controls. Antibody to gD, another important HSV-1 antigen, was assayed in parallel. No difference between RA patients and normal controls was found in levels of anti-gE antibody measured by reactivity of IgG F(ab')2 fragments reacting with gE coated to ELISA plates. No difference in anti-gD antibody was recorded between normals and patients with RA. Levels of IgG anti-IgE antibody did not correlate with quantitative elevations of serum rheumatoid factor (RF) in RA patients. When IgG anti-gE and anti-gD were assayed in 20 patients with juvenile rheumatoid arthritis and 22 children controls, no significant differences were noted. However, when individual RFs from patients with RA were tested for reactivity against a panel of affinity-isolated F(ab')2 antibodies to gE, some evidence for individual autospecificity was obtained. Four of 20 monoclonal IgM RFs produced from RA patients' B cells showed marked elevations of reactivity with some RA patients' F(ab')2 antibodies to gE. All four of the monoclonal RFs showing this specificity were derived from RA synovial tissue B cells. These findings may provide support for the concept that some RFs in patients with RA show individual specificity for internal image determinants of IgG antibodies to viral Fc gamma-binding proteins.     

EFFECT OF NITROGLYCERNE-INDUCED HYPOTENSION ON CANINE SPINAL CORD BLOOD FLOW

Twenty-four mongrel dogs were anaesthetized with pentobarbitoneand morphine sulphate. Neuromuscular blockade was achieved usingpancuronium. Spinal cord blood flow was measured using the radionuclidemicrosphere and hydrogen washout methods before, during, andfollowing nitroglycerine-induced hypotension. Heart rate, meanarterial pressure, cardiac output, pulmonary capillary wedgepressure, and acid-base balance were determined with each measurement.Mean arterial pressure was reduced by 50%. Spinal cord bloodflow, as measured by the microsphere method, increased duringthe period of hypotension, whereas values obtained using thehydrogen washout method were not significantly different fromthose at normotension. No significant change in spinal cordblood flow was detected by either method after the applicationof spinal distraction. Nitroglycerine acts predominantly onvenous capacitance vessels and it is postulated that perfusionpressure, and therefore flow, is maintained despite a reductionin arterial pressure. Presented in part at the Anual Meeting of the American Societyof Anesthesiologists, October 1985, San Francisco, California. ^*Shackleton Department of Anaesthetics, Southampton GeneralHospital, Shirley, Southampton, Hants SO9 4XY. Section of Orthopedic Surgery, Madison, Wisconsin.     

The use of Teflon-embedded calcium sulphate: dysprosium thermoluminescent dosimeters for chest radiography

As part of a U.S. multi-regional pilot study conducted by the six Centers for Radiological Physics, 12-mm-diameter by 0.4-mm-thick CaSO4:Dy Teflon-embedded discs were evaluated and used to measure patient entrance exposure on 60 "average" patients at 12 clinical centers. The discs were found to have adequate sensitivity, reproducibility and linearity up to 69.7 microC kg-1 (270 mR). The minimum measurable exposure was estimated as 0.4 microC kg-1 (1.5 mR). All responses were corrected for energy dependence, which varied +/- 20% from 1.7 to 6.5 mm Al half-value layer. Patient entrance exposure values ranged from 1.3 to 28 microC kg-1 (5 to 110 mR), with a median value of 5.2 microC kg-1 (20 mR). This value agreed with exposure measurements made on the chest radiography equipment using an ionization chamber and a phantom which simulated an "average" patient, and with published Nationwide Evaluation of X-Ray Trends (NEXT) data for the same period.     

The Effects of Magnetic Resonance Imaging on Implantable Pulse Generators

The effects of magnetic resonance imaging were assessed on four dual chamber and two single chamber pulse generators. The tests were performed with a resistive, water-cooled magnet operating at 0.15 T. The 6.4-MHz radiofrequency (RF) field was operated at a maximum power of 1,000 watts with a period adjusted from 130 to 500 ms. Reed switch closure occurred in all six pulse generators tested when placed near the entrance of the magnetic resonance imaging scanner, and the generators reverted to asynchronous operation unless programmed to the "magnet off" mode. None of the pulse generators exhibited any alterations in programmed parameters or in the ability to be reprogrammed after RF pulsing. When the RF field was turned on, there was no change in the asynchronous paced cycle length in four pulse generators; however, during RF scanning there was rapid cardiac stimulation at the RF pulse period in one single chamber and one dual chamber pulse generator.     

Developmental Neurotoxicity: Evaluation of Testing Procedures with Methylazoxymethanol and Methylmercury

Testing procedures for identification of potential developmentalneurotoxicants were evaluated using two prototypical developmentalneurotoxicants, methylazoxymethanol (MAM) and methylmercury(MeHg). Evaluation of offspring of LongEvans rats incorporatedassessments of developmental toxicity, neurochemistry, histology,and behavior, with most testing being completed near weaning.A number of endpoints in the testing strategy were sensitiveto the effects of prenatal exposure to MAM [30 mg/kg on GestationDay (GD) 15]: (1) MAM caused reduced neonatal body weights butdid not effect viability or postnatal survivorship; (2) measurementof total and regional brain weight and histological analysisshowed that a number of regions, the cortex and hippocampusin particular, were affected by MAM exposure; (3) an assay forglial fibrillary acidic protein (GFAP) showed that the concentrationof this protein was significantly increased in the cortex andhippocampus of treated offspring; (4) a T-maze delayed-alternationprocedure indicated that MAM-treated pups were slower in theacquisition phase of the task relative to control pups; (5)motor activity testing revealed hyperactivity in treated offspringthat persisted into adulthood; and (6) acoustic startle proceduresrevealed reduced startle amplitudes in preweanlings. Few endpointswere significantly affected by prenatal MeHg exposure (1, 2,or 4 mg/kg on GD 6–15). High fetal and neonatal mortalityand lower neonatal body weights were detected at the highestdose of MeHg. Although minimal effects of MeHg may reflect arelative insensitivity of the test species and/or the test methods,the combined results from both chemicals suggest that some proceduresnot currently required in the developmental neurotoxicity guidelinemay be useful in hazard identification, and further evaluationwith other chemicals, species, strains, and/or exposure paradigmsmay be warranted.