Larynx-associated lymphoid tissue (LALT) in young children

BACKGROUND: Mucosa-associated lymphoid tissue (MALT) plays a central role in mucosal immunity. Whereas the characteristics and function of MALT in the intestine are well established, almost nothing is known about MALT in the larynx. METHODS: In this study we examined the morphology and the lymphocyte subset composition of MALT in the larynges of children who had died of sudden infant death or various defined traumatic or nontraumatic causes. RESULTS: Organized lymphoid tissue was found in the supraglottic parts of the larynx in nearly 80% of the children in both groups. This lymphoid tissue showed all morphological signs of MALT, such as typical lymphoid follicles with germinal centers, infiltration of the overlying epithelium by lymphocytes, and high endothelial venules (HEV). Thus we will use the term LALT (larynx-associated lymphoid tissue) to refer to this tissue. The lymphoid follicles of LALT contained mainly B lymphocytes with some CD4+ lymphocytes in the germinal centers. Remarkably, T lymphocytes of both subset types and B lymphocytes were observed in comparable numbers in the parafollicular area. CONCLUSIONS: We assume that LALT is a physiological structure of the larynx in young children. The morphology and the distribution of lymphocyte subsets are similar to those of MALT in the human gut. LALT may be a regular part of the mucosal immune system in young children with the role of respiratory inductive site for mucosal immunity.     

Adrenocortical SPECT using iodine-131 NP-59

Adrenal scintigraphy with 131I-labeled 6-beta-iodomethyl-19-norcholesterol (NP-59) is a technically demanding and complex procedure. However, it can provide crucial and unique information about the functional status of the adrenal glands and guide the appropriate therapeutic management of patients with biochemically proven disease. Since the introduction of this new investigational drug, scintigraphic imaging has been performed using conventional planar techniques. We present an interesting case of primary aldosteronism in which planar scintigraphy and SPECT were combined in an attempt to increase the sensitivity of the study. SPECT revealed scintigraphic evidence of bilateral adrenocortical hyperplasia. Interestingly, the CT scan of this patient showed only an equivocal abnormality in the left adrenal gland, suggestive of an adenoma.     

The CTFA Evaluation of Alternatives Program: an evaluation of in vitro alternatives to the Draize primary eye irritation test. (Phase III) surfactant-based formulations

The CTFA Evaluation of Alternatives Program is an evaluation of the relationship between data from the Draize primary eye irritation test and comparable data from a selection of promising in vitro eye irritation tests. In Phase III, data from the Draize test and 41 in vitro endpoints on 25 representative surfactant-based personal care formulations were compared. As in Phase I and Phase II, regression modelling of the relationship between maximum average Draize score (MAS) and in vitro endpoint was the primary approach adopted for evaluating in vitro assay performance. The degree of confidence in prediction of MAS for a given in vitro endpoint is quantified in terms of the relative widths of prediction intervals constructed about the fitted regression curve. Prediction intervals reflect not only the error attributed to the model but also the material-specific components of variation in both the Draize and the in vitro assays. Among the in vitro assays selected for regression modeling in Phase III, the relationship between MAS and in vitro score was relatively well defined. The prediction bounds on MAS were most narrow for materials at the lower or upper end of the effective irritation range (MAS = 0-45), where variability in MAS was smallest. This, the confidence with which the MAS of surfactant-based formulations is predicted is greatest when MAS approaches zero or when MAS approaches 45 (no comment is made on prediction of MAS > 45 since extrapolation beyond the range of observed data is not possible). No single in vitro endpoint was found to exhibit relative superiority with regard to prediction of MAS. Variability associated with Draize test outcome (e.g. in MAS values) must be considered in any future comparisons of in vivo and in vitro test results if the purpose is to predict in vivo response using in vitro data.     

"Back pain" in teenagers and young adults]

The studies aimed to estimate an incidence of the low back pain (LBP) in the youngsters and teenagers and correlating it with risk factors. A groups of 2,346 secondary school pupils (1,704 girls and 642 boys) of a mean age 17 +/- 1 yrs, and 970 high-school students (532 women and 438 men) of a mean age 24 +/- 2 yrs have been examined. Low back pain has been seen in 1,416 out of 2,346 secondary school pupils (60%), and in 32% of the examined students. Statistical analysis with chi 2 test has confirmed a correlation between LBP and such risk factors as the incorrect sedentary position (p < .001 for pupils, and p < .02 for students), and smoking (p < .001 for students and p < .02 for pupils).     

Effects of sleeping in a chemical protective mask on sleep quality and cognitive performance

PURPOSE: We wanted to determine whether sleep is disrupted when soldiers sleep in a new chemical protective mask, the M40. Sleep quantity and quality, extent of protection provided by the mask during sleep, and next day performance were assessed. METHOD: After several days of training, 9 male soldiers slept with and without the M40 mask on four occasions. RESULTS: Soldiers were able to tolerate the mask for most or all of the night. However, sleep, as assessed by wrist-worn activity monitors, was significantly disturbed. Minutes (mean +/- SEM) of waking significantly increased, from 25 +/- 2.1 to 86 +/- 8.5 per night (p < 0.001), and number of awakenings rose from 8 +/- 0.6 to 20 +/- 0.9 (p < 0.0001). Soldiers reported that it took longer and was more difficult to fall asleep when wearing the mask. Errors on a choice reaction time task increased significantly and subjects reported greater fatigue and sleepiness the day after sleeping in the mask. Protection provided by the masks varied substantially among subjects and declined over the course of the study. Some soldiers were protected throughout the night but others were only protected intermittently. CONCLUSION: We conclude that sleeping in the chemical protective mask should only be done when necessary, given the adverse effects on sleep and daytime function, as well as the variability of protection, of the mask.     

Correcting temperature-sensitive protein folding defects

Recently, we found that different low molecular weight compounds, all known to stabilize proteins in their native conformation, are effective in correcting the temperature-sensitive protein folding defect associated with the deltaF508 cystic fibrosis transmembrane regulator (CFTR) protein. Here we examined whether the folding of other proteins which exhibit temperature-sensitive folding defects also could be corrected via a similar strategy. Cell lines expressing temperature-sensitive mutants of the tumor suppressor protein p53, the viral oncogene protein pp60src, or a ubiquitin activating enzyme E1, were incubated at the nonpermissive temperature (39.5 degrees C) in the presence of glycerol, trimethylamine N-oxide or deuterated water. In each case, the cells exhibited phenotypes similar to those observed when the cells were incubated at the permissive temperature (32.5 degrees C), indicative that the particular protein folding defect had been corrected. These observations, coupled with our earlier work and much older studies in yeast and bacteria, indicate that protein stabilizing agents are effective in vivo for correcting protein folding abnormalities. We suggest that this type of approach may prove to be useful for correcting certain protein folding abnormalities associated with human diseases.     

Changes in RBE of 14-MeV (d + T) neutrons for V79 cells irradiated in air and in a phantom: is RBE enhanced near the surface?

PURPOSE: The relative biological effectiveness (RBE) for inactivation of V79 cells was determined as function of dose at the Heidelberg 14-MeV (d + T) neutron therapy facility after irradiation with single doses in air and at different depths in a therapy phantom. Furthermore, to assess the reproducibility of RBE determinations in different experiments we examined the relationship between the interexperimental variation in radiosensitivity towards neutrons with that towards low LET 60Co photons. METHODS: Clonogenic survival of V79 cells was determined using the colony formation assay. The cells were irradiated in suspension in small volumes (1.2 ml) free in air or at defined positions in the perspex phantom. Neutron doses were in the range, Dt = 0.5-4 Gy. 60Co photons were used as reference radiation. RESULTS: The radiosensitivity towards neutrons varied considerably less between individual experiments than that towards photons and also less than RBE. However, the mean sensitivity of different series was relatively constant. RBE increased with decreasing dose per fraction from RBE = 2.3 at 4 Gy to RBE = 3.1 at 0.5 Gy. No significant difference in RBE could be detected between irradiation at 1.6 cm and 9.4 cm depth in the phantom. However, an approximately 20% higher RBE was found for irradiation free in air compared with inside the phantom. Combining the two effects, irradiation with 0.5 Gy free in air yielded an approximately 40% higher RBE than a dose of 2 Gy inside the phantom. CONCLUSION: The measured values of RBE as function of dose per fraction within the phantom is consistent with the energy of the neutron beam. The increased RBE free in air, however, is greater than expected from microdosimetric parameters of the beam and may be due to slow recoil protons produced by interaction of multiply scattered neutrons or to an increased contribution of alpha particles from C(n, alpha) reactions near the surface. An enhanced RBE in subcutaneous layers of skin combined with an increase in RBE at low doses per fraction outside the target volume could potentially have significant consequences for normal tissue reactions in radiotherapy patients treated with fast neutrons.     

Pharmacology and subcellular distribution of [3H]rilmenidine binding sites in rat brain

We have previously reported that in rat brain membranes, [3H]rilmenidine, in addition to labelling alpha2-adrenoceptors and the I2B-subtype of imidazoline receptor binding site (I2B-RBS), may label an additional I-RBS population, distinct from previously classified I1-RBS and I2-RBS. In this study, using crude or fractionated rat brain membranes we examined the possible association of [3H]rilmenidine-labelled I-RBS with the A- and B-isoforms of monoamine oxidase (MAO) by studying the inhibition of [3H]rilmenidine binding by a number of MAO inhibitors; and comparing the maximal binding density (Bmax) and subcellular distribution of [3H]rilmenidine binding sites with that of MAO-A and MAO-B catalytic sites labelled by [3H]RO41-1049 and [3H]RO19-6327 and 12-RBS labelled by [3H]2-BFI. Inhibition of [3H]rilmenidine binding by all MAO inhibitors tested produced very shallow curves (slope 0.29-0.56). Clorgyline and moclobemide (selective MAO-A inhibitors) displayed moderate affinities (60-140 nM), while pargyline (non-selective MAO-inhibitor), RO41-1049 (selective MAO-A inhibitor) and RO19-6327 (selective MAO-B inhibitor) exhibited very low affinities (> 2 microM) for 50-75% of [3H]rilmenidine-labelled I-RBS in crude brain membranes and even lower affinity for the remaining binding. Under identical buffer conditions, the Bmax of [3H]rilmenidine-labelled I-RBS (1.45+/-0.14 pmol/mg protein) was considerably lower than those of MAO-A (13.10+/-0.15 pmol/mg) and MAO-B (10.35+/-0.50 pmol/mg) sites. These results suggest that [3H]rilmenidine does not interact directly with the active catalytic site of either MAO enzyme and could at best only associate with a subpopulation of MAO molecules. Binding studies on five fractions of rat cortex homogenates-nuclear (N), heavy (M) and light (L) mitochondrial, microsomal non-mitochondrial (P), and soluble cytosolic (S) fractions-revealed that 45% of total [3H]rilmenidine binding was present in the P fraction cf. 20 and 23% in the M and L fractions, in contrast to [3H]RO19-6327 and [3H]2-BFI which bound 11-13% in the P fraction and 36-38% and 35-44% in the M and L fractions, respectively. Binding of all ligands in the N fraction was 6-15% of total. These studies reveal that [3H]rilmenidine-labelled I-RBS, unlike the I2-RBS, are not predominantly associated with mitochondrial fractions containing the MAO enzymes (and cytochrome oxidase activity), but appear to be distributed in both the mitochondrial and plasma membrane fractions in rat cerebral cortex.     

Dissociation between the potency and reversibility of the insulinotropic action of two meglitinide analogues

The non-sulphonylurea hypoglycaemic agent repaglinide is about one order of magnitude less potent, in terms of insulinotropic efficiency, than S3075, another meglitinide analogue. In the present study, the effects of these two drugs upon 86Rb outflow, 45Ca efflux and insulin release from prelabelled rat pancreatic islets were investigated in a perifusion system. At a concentration of 10 microM, which is sufficient to evoke a maximal secretory response in incubated islets, both agents inhibited 86Rb efflux from islets perifused in the absence of D-glucose, and stimulated both 45Ca efflux and insulin release from islets perifused in the presence of 6 mM D-glucose. The stimulation of 45Ca efflux from prelabelled islets was suppressed in the absence of extracellular Ca2+. The cationic and secretory response to repaglinide differed, however, from that evoked by S3075, in persisting for at least 20 min after removal of the drug from the perifusion medium, whilst the changes in 86Rb outflow, 45Ca efflux and insulin release caused by S3075 were rapidly reversible. These findings indicate that there is no parallel between the insulinotropic efficiency of distinct meglitinide analogues, and the reversibility of their functional effects. Since a comparable dissociation was recently documented in the case of hypoglycaemic sulphonylureas, the present observations reinforce the view that distinct molecular determinants may rule the relative insulinotropic potency of sulphonylureas and structurally related meglitinide analogues, on one hand, and the reversibility of their biological action, on the other hand.