Prominin-2 is a cholesterol-binding protein associated with apical and basolateral plasmalemmal protrusions in polarized epithelial cells and released into urine

Prominin-2 is a pentaspan membrane glycoprotein structurally related to the cholesterol-binding protein prominin-1, which is expressed in epithelial and non-epithelial cells. Although prominin-1 expression is widespread throughout the organism, the loss of its function solely causes retinal degeneration. The finding that prominin-2 appears to be restricted to epithelial cells, such as those found in kidney tubules, raises the possibility that prominin-2 functionally substitutes prominin-1 in tissues other than the retina and provokes a search for a definition of its morphological and biochemical characteristics. Here, we have investigated, by using MDCK cells as an epithelial cell model, whether prominin-2 shares the biochemical and morphological properties of prominin-1. Interestingly, we have found that, whereas prominin-2 is not restricted to the apical domain like prominin-1 but is distributed in a non-polarized fashion between the apical and basolateral plasma membranes, it retains the main feature of prominin-1, i.e. its selective concentration in plasmalemmal protrusions; prominin-2 is confined to microvilli, cilia and other acetylated tubulin-positive protruding structures. Similar to prominin-1, prominin-2 is partly associated with detergent-resistant membranes in a cholesterol-dependent manner, suggesting its incorporation into membrane microdomains, and binds directly to plasma membrane cholesterol. Finally, prominin-2 is also associated with small membrane particles that are released into the culture media and found in a physiological fluid, i.e. urine. Together, these data show that all the characteristics of prominin-1 are shared by prominin-2, which is in agreement with a possible redundancy in their role as potential organizers of plasma membrane protrusions.

Inhibition of WT1 and bcl2 in leukemic cell lines by small interfering RNA (siRNA)

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The expression of Wilm‘s tumor gene-1 (wt1) and bcl-2 is considered to have a proliferating and survival supporting effect in leukemia blast cells. The downregulation of wt1 by means of antisense-oligonucleotides and ribozymes revealed an inhibition of cell proliferation and induction of cell death. Here we describe the effect of siRNA against wt1 and bcl-2 in leukemic cell lines. RT-PCR and western blot analyses were performed to examine wt1 and bcl-2 gene expression in transfected leukemia cell lines. Apoptosis was detected with FACS analysis. K562 and HL-60 cell lines transfected with wt1 siRNA showed decreasing levels of wt1 mRNA and protein expression after 24 and 48 hours. The cell proliferation was reduced between 45% and 76% 48 hours after transfection, and apoptosis increased from 6.6 % in control cells to 12.2 % 24 hours after transfection in transfected cells. 48 hours after transfection the amount of apoptotic cells increased up to 45 % in transfected cells. Bcl-2 siRNA only induced apoptosis in about 15% of the cells. The combination of wt1 and bcl-2 siRNA had no additive effect on the induction of apoptosis. The expression of wt1 seems to be more important for cell survival than expression of the anti-apoptotic gene bcl-2. We therefore consider siRNA targeting human wt1 as possible tool against leukemic cells overexpressing wt1.

No significant financial relationships to disclose.

Psoriasis confined strictly to vitiligo areas - a Koebner-like phenomenon?

Vitiligo and psoriasis are both common skin disorders. However, psoriasis strictly confined to pre-existing vitiligo areas is rare and suggests a causal relationship. We report here on two patients with a strict anatomical colocalization of vitiligo and psoriasis. The histopathological examinations showed typical changes for both diseases together with a dense infiltrate of CD4+ and CD8+ T cells. By immunohistochemistry, intracytoplasmatic granzyme B and tumour necrosis factor alpha (TNF-alpha) were detected within the T-cell population, suggesting the functional activity of these cells and the creation of a local T helper 1 (Th1)-cytokine milieu. Additionally, in one patient we could identify anti-melanocytic T cells by tetramer staining and enzyme-linked immunospot (ELISPOT) analysis. These skin-infiltrating lymphocytes might trigger, by the local production of Th-1 cytokines such as TNF-alpha and interferon-gamma (IFN-gamma), the eruption of psoriatic plaques in patients with a genetic predisposition for psoriasis.

Fatigue in multiple sclerosis: an example of cytokine mediated sickness behaviour?

BACKGROUND

Fatigue is a major complaint of multiple sclerosis (MS) patients. However, little is known about its pathophysiological mechanisms. Evidence from chronic fatigue syndrome and studies on sickness behaviour suggest that immune and neuroendocrine factors may play a causative role in the development of fatigue.

METHODS

We compared whole blood stimulatory capacity for pro- (TNFalpha, IFNgamma) and anti-inflammatory cytokines (IL-10) as well as hypothalamo-pituitary-adrenal (HPA) axis function in 15 MS patients with marked fatigue and 15 patients without fatigue as determined by the Fatigue Severity Scale (FSS).

RESULTS

Proinflammatory cytokines were significantly higher (TNFalpha: 478.9 v 228.2 pg/ml, p = 0.01; IFNgamma: 57.6 v 27.8 pg/ml; p = 0.01) in MS patients with fatigue. Furthermore, TNFalpha values significantly correlated with daytime sleepiness as measured by the Epworth Sleepiness Scale (r = 0.64, p = 0.001). Controlling for disease activity (as measured by the Cambridge Multiple Sclerosis Basic Score), disease duration, Expanded Disability Status Scale, and depression further increased the correlation of cytokine production and fatigue. HPA axis activity was not related to fatigue but was modestly correlated with cognitive impairment.

CONCLUSION

Our data suggest that fatigue in MS is at least partially mediated through activation of proinflammatory cytokines. In line with earlier findings, HPA axis dysfunction seems not to be relevant in MS fatigue pathogenesis but appears to be linked to cognitive impairment. Our findings suggest that increased levels of inflammatory cytokines may be involved in MS fatigue. Investigation of cytokine profiles may increase the understanding of fatigue pathogenesis in MS.

Flow cytometric analysis of effusions in dogs and cats with the automated haematologyanalyser ADVIA 120

Samples were aspirated from 12 thoracic effusions, 10 abdominal effusions and four pericardial effusions in 17 dogs and nine cats. They were analysed cytometrically with the ADVIA 120 flow cytometer and the results were compared with the results of cytological examinations of May-Grünwald-Giemsa-stained smears. The conventional cytology revealed a purulent or pyogranulomatous inflammation in 12 of the animals, lymphoma in six, malignant histiocytosis in two, and an unspecified carcinoma in two; two animals had a chylous effusion, two had a modified transudate, and one dog had an idiopathic pericardial haemorrhage. The flow cytometric analysis was based on cellular volume, peroxidase staining intensity and the determination of nuclear lobularity, and made it possible to identify predominant cell lineages and cell debris, which were shown in characteristic cytograms. Inflammatory effusions, monocytic proliferation and lymphoma were easily detected, but carcinoma cells and mesothelial cells were classified as 'mononuclear blasts'.

Clinical characterization of patients with hereditary pancreatitis and mutations in the cationic trypsinogen gene

PURPOSE

We determined the clinical manifestations of hereditary pancreatitis in nearly 30 families.

PATIENTS AND METHODS

The two trypsinogen mutations N29I and R122H were identified in a group of 550 patients with chronic pancreatitis of unclear origin. The following criteria were used to characterize the severity of chronic pancreatitis (one point each): calcifications, cysts, dilation of the pancreatic duct, diabetes, hospital treatment, and operation. Stages were defined as stage 0 (no points), stage 1 (one to two points), stage 2 (three to four points), and stage 3 (more than four points). Smoking and drinking habits were also recorded.

RESULTS

Six families with the N29I mutation (25 subjects with the mutation) and 21 families with the R122H mutation (76 subjects with the mutation) were identified. The median ages for the onset of disease were 11 years in N29I and 10 years in R122H patients. The severity of chronic pancreatitis and symptoms were similar for both mutations. About 26% (n = 26) of the 101 subjects carrying a mutation were asymptomatic, and 42% (n = 42) had mild disease (stage 1). Twenty-nine percent (n = 29) had moderate disease (stage 2), and only 4% (n = 4) had severe disease (stage 3).

CONCLUSIONS

Symptoms of patients with the N29I or R122H trypsinogen mutation were generally similar. The majority of subjects with trypsinogen mutations had mild disease or was asymptomatic.

How robust is the IAT? Measuring and manipulating implicit attitudes of East- and West-Germans

We investigated consequences of priming East-West-German related self-knowledge for the strength of implicit, ingroup-directed positive evaluations among East- and West-Germans. Based on previous studies we predicted opposite effects of self-knowledge priming for East- and West-Germans. Since in general the East-German stereotype is regarded as more negative than the West-German one, bringing to mind East-West-related self-knowledge (relative to neutral priming) was expected to attenuate ingroup favoritism for East-Germans, but to increase it for West-Germans. After having fulfilled the priming tasks, participants worked on an IAT-version in which the to be classified stimuli were East- or West-German city names (dimension 1) and positive or negative adjectives (dimension 2). Results of Experiment 1 showed (a) that East- and West-German students implicitly evaluated their ingroups as more positive than the outgroups and (b) confirmed the predictions of the priming influence. Experiment 2 replicated these findings with more representative samples from East- and West-Germany. The results are discussed with regard to underlying processes of implicit attitudes in intergroup contexts.

Endogenous ouabain and its binding globulin: effects of physical exercise and study on the globulin's tissue distribution

Ouabain, that has been isolated from bovine adrenals and hypothalamus, is a new cardiotonic steroid hormone, which is either synthesized in the adrenals or stored there after it has absorbed from the diet. Little is known in vivo which events may lead to the release of ouabain into blood. Moreover, a binding protein for cardiotonic steroids exists in blood, which binds cardiac glycosides with high affinity. It may affect the action of endogenous ouabain on heart and circulation, but the physiological function of this protein is unclear. To realize, which physiological stimuli in vivo may affect blood concentrations of endogenous ouabain and which function the cardiotonic binding protein may have in modulating ouabain effects, the effect of physical exercise on endogenous ouabain was studied and the tissue distribution of its binding protein was investigated. We found that endogenous ouabain changes rapidly in blood upon physical exercise and behaves like expected for a hormone of circulation. The cardiotonic steroid binding globulin shows the highest concentration in the kidney, which suggests that sodium pumps of the kidney are protected against its inhibition by ouabain which would lead not only to natriuresis but also to a deleterious loss of glucose, amino acids and phosphate.

Differential optical absorption spectroscopy instrument for stratospheric balloonborne trace-gas studies

A newly developed UV-visible instrument for differential optical absorption spectroscopic measurements of atmospheric trace gases from balloon platforms is described. Direct solar light at daytime in the near-ultraviolet (320.6-422.6-nm) and the visible (417.6-670.7-nm) spectral ranges can be simultaneously analyzed for the atmospheric column abundances or profiles of O(3), NO(2), NO(3), BrO, OClO, O(4), H(2)O, and possibly other species (HNO(2), IO, CH(2)O). Compared with previously used balloonborne UV-visible spectrometers, the instrument has the superior properties of low mass (42 kg), low power consumption (30 W), decreased spectral drift that is caused by temperature and pressure changes, low detector dark current, and low spectrometer stray light. The three last-named characteristics are achieved by enclosure of the entire spectrometer in a pressurized and thermostated container and by inclusion of separately thermostated photodiode array detectors. The optical setup is simplified to reduce its weight. The spectral stray light is reduced by suppression of the higher-order and zero-order grating reflections by use of light traps and in the UV by addition of a dispersive prism preanalyzer. The major instrumental design characteristics and the instrumental performance as tested in the laboratory and during several stratospheric balloon flights are reported.

Attempts to isolate Helicobacter from cattle and survival of Helicobacter pylori in beef products

This study focused on important factors related to the potential of cattle and beef products to transmit Helicobacter pylori to humans. Mucosal samples were collected from the rumen and abomasum of 105 cattle and were plated on a selective medium to isolate Helicobacter spp.; none of the samples examined contained these bacteria. Studies were also conducted to determine how long H. pylori survives in refrigerated or frozen ground beef; results indicated that the microorganism dies rapidly in ground beef, whether refrigerated or frozen. Packaging in vacuum or air had little effect on survival of the organism. The number of H. pylori decreased in refrigerated samples from 3.3 log10 CFU/g on day 0 to 1.4 log10 CFU/g on day 6. H. pylori died even more rapidly when frozen, decreasing from 3.3 log10 CFU/g on day 0 to 0.5 log10 CFU/g on day 6. Retail beef cuts (n = 20) were also examined for the presence of H. pylori by direct plating on a selective medium and by incubation in an enriched broth followed by plating on a selective medium. None of the retail samples contained H. pylori. This research suggests that transmission of H. pylori from beef and beef products is not a primary factor in the high prevalence of this bacterium in humans.

Mechanisms of nocturnal oxyhemoglobin desaturation in children and adolescents with sickle cell disease

Oxyhemoglobin desaturation in patients with sickle cell disease has been proposed as a possible mechanism in the initiaton of vasco-occlusive pain crises. Nocturnal oxyhemoglobin desaturation (NOD) has been described with a prevalence of up to 40% in children and adolescents with sickle cell disease. The objective of this study was to evaluate the mechanisms of nocturnal oxyhemoglobin desaturation in sickle cell disease and determine the role of obstructive sleep apnea. We performed 16-channel polysomnograms and pulmonary function testing in 20 patients with sickle cell disease (ages 7-21 years) who had documented desaturation on home oximetry studies. The median saturation awake was 94% (quartile range, 88-95). Median saturation during REM sleep was 93.5% (88-95) and during non-REM sleep 93.5% (87.5-95). The median respiratory disturbance index was low (1.35 quartile range, 0.25-2.85). Twelve patients had no obstructive apnea recorded, while 3 patients had a total of 9 or 10 episodes during the entire study. The median snoring time was 5. 65% of total sleep time (quartile range, 1.35-22.65). There was no correlation between number of obstructive apneas and mean sleeping saturation (r = 0.012, p = 0.95). There was no correlation between pulmonary function data and prevalence of NOD. There was a strong, positive correlation between sleeping and awake saturation (r = 0.96, p < 0.001). We conclude that while nocturnal oxyhemoglobin desaturation may be common in children and adolescents with sickle cell disease, upper airway obstruction does not appear to play an important role in its genesis.

Efficacy of bupropion in tricyclic-resistant or intolerant patients

Available evidence is reviewed concerning the antidepressant efficacy of bupropion in patients who had failed to respond to or been unable to tolerate tricyclic antidepressants (TCAs) during prior episodes of depression. Inpatients classified as TCA nonresponders were randomly assigned to double-blind treatment with bupropion (N = 19) or placebo (N = 11). Patients receiving bupropion showed an excellent antidepressant response, whereas those receiving placebo showed minimal improvement (p less than .001). Inpatients who were classified as TCA responders responded well to double-blind treatment with bupropion, but also had a substantial, although significantly smaller (p less than .05), response to placebo. Outpatients (N = 33) with a history of nonresponse or nonresponse plus intolerance to TCAs showed marked improvement during open treatment with bupropion. The results from both double-blind and open treatment with bupropion demonstrate that this drug offers a promising alternative therapy for patients with a history of poor response to TCAs.