Cellular expression and genetic control of ABH antigens in primary sensory neurons of marmoset, baboon and man

ABH antigens have been demonstrated in the posterior root ganglia (PRG) of 3 primate species (marmoset, baboon and man). Their expression corresponded to the ABO phenotype of the individual and was independent of the secretor gene. In marmosets more cells were positive for H (33 +/- 9%) than for A (19 +/- 6%). In baboons A or B antigens were more easily detected (66 +/- 9%) than the H antigens (48 +/- 5%). In humans more than two-thirds of PRG cells were positive for H but only a small proportion of these were positive for A or B. The ABH antigens were found mainly in the small and intermediate-size neurons whose central processes project to lamina II of the spinal cord posterior horn. Unipolar neurons of the Gasserian ganglion, neurons of the mesencephalic nucleus of the trigeminal nerve and of some visceral ganglia have also been shown to express these antigens which are also present in the fibre layer and glomeruli of the olfactory bulbs.     

Optimization of biomathematical model predictions for cognitive performance impairment in individuals: accounting for unknown traits and uncertain states in homeostatic and circadian processes

Current biomathematical models of fatigue and performance do not accurately predict cognitive performance for individuals with a priori unknown degrees of trait vulnerability to sleep loss, do not predict performance reliably when initial conditions are uncertain, and do not yield statistically valid estimates of prediction accuracy. These limitations diminish their usefulness for predicting the performance of individuals in operational environments. To overcome these 3 limitations, a novel modeling approach was developed, based on the expansion of a statistical technique called Bayesian forecasting. The expanded Bayesian forecasting procedure was implemented in the two-process model of sleep regulation, which has been used to predict performance on the basis of the combination of a sleep homeostatic process and a circadian process. Employing the two-process model with the Bayesian forecasting procedure to predict performance for individual subjects in the face of unknown traits and uncertain states entailed subject-specific optimization of 3 trait parameters (homeostatic build-up rate, circadian amplitude, and basal performance level) and 2 initial state parameters (initial homeostatic state and circadian phase angle). Prior information about the distribution of the trait parameters in the population at large was extracted from psychomotor vigilance test (PVT) performance measurements in 10 subjects who had participated in a laboratory experiment with 88 h of total sleep deprivation. The PVT performance data of 3 additional subjects in this experiment were set aside beforehand for use in prospective computer simulations. The simulations involved updating the subject-specific model parameters every time the next performance measurement became available, and then predicting performance 24 h ahead. Comparison of the predictions to the subjects' actual data revealed that as more data became available for the individuals at hand, the performance predictions became increasingly more accurate and had progressively smaller 95% confidence intervals, as the model parameters converged efficiently to those that best characterized each individual. Even when more challenging simulations were run (mimicking a change in the initial homeostatic state; simulating the data to be sparse), the predictions were still considerably more accurate than would have been achieved by the two-process model alone. Although the work described here is still limited to periods of consolidated wakefulness with stable circadian rhythms, the results obtained thus far indicate that the Bayesian forecasting procedure can successfully overcome some of the major outstanding challenges for biomathematical prediction of cognitive performance in operational settings.     

Genetics of ABO, H, Lewis, X and Related Antigens

The present knowledge on chemical, enzymatic, serologic and genetic aspects of ABH antigens is reviewed in an effort to produce a simple and coherent genetic model for the biosynthesis of these antigens and chemically related structures. The genetic control of type 1 (Le(a), Le(b), Le(c) and Le(d)), type 2 (X, Y, I, and H), type 3 and type 4 ABH and related antigens in different animal and human tissues is analyzed, taking into account the properties of the glycosyltransferases which are involved in their synthesis and considering possible competition for common acceptor and donor substrates. The phylogeny of ABH determinants shows that they appeared as tissular antigens much earlier than as red cell antigens. The ontogeny of ABH antigens suggests that they behave as differentiation antigens, and an effort is made to correlate their tissular distribution in the adult with the embryological origin of each tissue.     

The 2005 Italian Quality Control Study for the evaluation of CD4 cells in centers involved in the treatment of HIV type 1 patients

We report the results of an external quality control program, including 17 Italian centers involved in the care of patients infected by HIV, to evaluate CD4 T cell count proficiency and reproducibility. The centers received two commercial stabilized blood preparations, one with "normal" and one with "low" CD4 T cell content. The centers were asked to process the samples two times, 1 week apart, with the same procedure used for samples from HIV patients. Most centers showed a good performance of CD4 frequency and absolute count determinations. In particular, the "low" sample was correctly analyzed by all centers; only two underestimated the "normal" sample CD4 frequency, and only one underestimated the CD4 absolute count by >100 CD4 cells/microl. Overall, our data suggest that most Italian laboratories provide reliable and reproducible results in evaluating CD4 T cells in HIV(+) samples.     

Immunohistologic pattern of type 1 (Lea, Leb) and type 2 (X, Y, H) blood group-related antigens in the human pyloric and duodenal mucosae

Type 1 antigens (Lea and Leb) of the pyloric mucosa are restricted to the mucus cells of the surface epithelium and the neck. In the duodenum they are present in absorptive and goblet cells of duodenal villi as well as in the glands of Lieberkühn. Type 2 antigens (X, Y, and H) are also present in these areas of the mucosa, and both type 1 and type 2 antigens, in this superficial location, are under the control of the secretor gene. In addition, type 2 antigens are also present in the mucus cells of pyloric and Brunner's glands, but in this deep location they are not controlled by the secretor gene. These results suggest the existence of two differentiation patterns for the expression of glycosyltransferases in the stem cells. The upward differentiation process would favor the expression of the alpha-2-L-fucosyltransferase coded by the Se gene, and the downward differentiation process would favor the expression of the alpha-2-L-fucosyltransferase coded by the H gene. The knowledge of the distribution and the genetic control of type 1 and type 2 antigenic determinants in normal gastrointestinal tract may help to interpret the modifications in the expression of these antigens in pathologic conditions such as neoplasia.     

Cellular expression of H and B antigens in the rat olfactory system during development

Developmental expression of H and B antigens in the rat olfactory system was studied from the embryonic day 14 up to the postnatal day 30. The H antigen was detected in the olfactory and vomeronasal epithelia as early as fetal day 14, whereas the B antigen first appeared 2 days later. The anti-H reagent reacted strongly with sensory receptors and weakly with supporting cells in both epithelia, whereas the anti-B reagent was specific for olfactory receptors. In the main olfactory epithelium, the H antigen was expressed from fetal day 19 by most of the receptor cells, whereas the B determinant was expressed from fetal day 16 to postnatal day 3 by only a few neuroreceptors mostly located near the epithelial surface. After the postnatal day 3, B positive neurons increased in number from the periphery toward the deeper mucosal layers and they were distributed over 3/4 of the epithelial thickness in 15- and 30-day-old rats. In the main olfactory bulb, a widespread glomerular B staining with variable binding intensity between adjacent glomeruli was already observed at birth. The vomeronasal receptor cells and their axon terminals in the accessory olfactory bulb exhibited a comparable developmental expression of the B antigen. Results suggest that the B antigen could be regarded as a marker of neuronal maturation of both the olfactory and vomeronasal receptor cells; moreover, its first appearance in the receptor cells might be temporally related to the formation of synapses between receptor axons and deutoneurons in the bulb.     

Specific removal of anti-red cell blood group activity from anti-HLA lymphocytotoxic sera and purification of anti-A and anti-B antibodies with lymphocytotoxic activity

Lymphocytotoxic antibodies to the red cell blood groups A and B were purified from human sera by elution from synthetic immunoadsorbents (Synsorbs from Chembiomed). The lymphocytotoxic activity of the eluted antibodies was better preserved when elution was carried out at pH 11, whereas it was less stable when elution was performed at pH3. In addition, complete removal of anti-red cell blood group activity from an anti-HLA serum was easily obtained by adsorption on the corresponding Synsorb without loss of anti-HLA activity.