The cytoplasmic tyrosine motifs in full-length glycoprotein 130 have different roles in IL-6 signal transduction

The function of the signal-transducing receptor subunit glycoprotein 130 (gp130) in the IL-6-receptor complex has previously been studied using carboxyl-terminal deletion mutants or a truncated molecule of approximately 60 membrane-proximal amino acids (containing box 1 and box 2) linked to the individual gp130 tyrosine motifs. However, the redundancy of the tyrosine motifs within the cytoplasmic part of gp130 has been neglected. Here we describe the analysis of the function of the individual cytoplasmic tyrosine residues of gp130 in the context of the full-length receptor protein in IL-6 signaling as measured by STAT activation, acute phase protein induction, and stimulation of proliferation. Add-back receptor mutants containing only one cytoplasmic tyrosine have been generated and tested for their efficiency in IL-6 signal transduction. Our studies revealed that tyrosine motifs which have been described to recruit STAT proteins are not equivalent with respect to their potential to activate STAT factors and acute phase protein gene promoters: the two distal tyrosines, Tyr905 and Tyr915, of gp130 were more potent than Tyr767 and Tyr814. Surprisingly, Tyr905 and Tyr915 mediate acute phase protein gene promoter activation stronger than the wild-type receptor containing all six cytoplasmic tyrosine residues. In contrast, Ba/F3 cells stably transfected with add-back receptors containing Tyr767 or Tyr905 were more sensitive to IL-6-induced proliferation than cells expressing the other add-back receptor mutants. Thus, the tyrosine residues in the cytoplasmic part of gp130 were found to contribute differentially to IL-6 signal transduction in the full- length gp130 protein.

Enrichment and detection of live antigen-specific CD4(+) and CD8(+) T cells based on cytokine secretion

Following appropriate antigen-specific stimulation, CD4(+) and CD8(+) T lymphocytes rapidly express cytokines. Based on this stimulation-induced cytokine secretion and using cell surface affinity matrix technology we have developed a new method that permits specific, rapid and efficient detection, isolation and characterization of live antigen-specific CD4(+) and CD8(+) T lymphocytes. The power of this technique is demonstrated here for HLA-A0201-restricted influenza matrix protein peptide 58-66-specific CD8(+) cytotoxic T lymphocytes, influenza A virus- and recombinant tetanus toxin C fragment-specific Th1 cells and tetanus toxoid-specific Th2 cells.

LPS and TNFalpha induce SOCS3 mRNA and inhibit IL-6-induced activation of STAT3 in macrophages

Recent findings indicate that cytokine signaling can be modulated by other mediators of simultaneously activated signal transduction pathways. In this study we show that LPS and TNFalpha are potent inhibitors of IL-6-mediated STAT3 activation in human monocyte derived macrophages, rat liver macrophages and RAW 264.7 mouse macrophages but not in human hepatoma cells (HepG2) or in rat hepatocytes. Accordingly, LPS and TNFalpha were found to induce the expression of SOCS3 mRNA in each of the investigated type of macrophages but not in HepG2 cells. Using a specific inhibitor, evidence is presented that the p38 MAP kinase might be involved, especially for the inhibitory effect of TNFalpha.

Enrichment and detection of live antigen-specific CD4(+) and CD8(+) T cells based on cytokine secretion

Following appropriate antigen-specific stimulation, CD4(+) and CD8(+) T lymphocytes rapidly express cytokines. Based on this stimulation-induced cytokine secretion and using cell surface affinity matrix technology we have developed a new method that permits specific, rapid and efficient detection, isolation and characterization of live antigen-specific CD4(+) and CD8(+) T lymphocytes. The power of this technique is demonstrated here for HLA-A0201-restricted influenza matrix protein peptide 58-66-specific CD8(+) cytotoxic T lymphocytes, influenza A virus- and recombinant tetanus toxin C fragment-specific Th1 cells and tetanus toxoid-specific Th2 cells.

The relationship between leg stepping pattern and yaw torque oscillations in curve walking of two crayfish species

Curve walking in two species of crayfish, Procambarus clarkii and Astacus leptodactylus, was investigated to test whether the mechanism underlying curve walking is the synchronous action of a centrally pre-programmed leg tripod or whether it is the action of one principal leg that produces the main body yaw torque. Curve walking was induced by an optomotor visual stimulus, and the yaw torque produced by the tethered animals was measured in open-loop conditions. Our main results suggest that the yaw torque oscillations in both P. clarkii and A. leptodactylus are related to the movement of outer leg 4 (i.e. leg 4 on the outside of the turn). That is, the peaks in the yaw torque occur, on average, in synchrony with the power stroke of outer leg 4. When comparing the results of this open-loop experiment on P. clarkii with results previously obtained for curve walking in untethered individuals of the same species, we found a much higher variability in leg coordination in the open-loop situation. Similarly, here we did not find the same level of synchrony in the tripod (formed by outer leg 4 and inner legs 2 and 5) observed during untethered free walking. Therefore, we suggest that tethered conditions may diminish the need for stability and thus allow outer leg 4 to produce a body rotation regardless of the leg stepping configuration. The characteristics of leg 4 are in line with its major role in turning. According to previous studies, legs 4 provide the largest force and the largest step amplitude during walking, and their force includes both a pulling and a pushing component which can facilitate the control of turning. Although it is apparent that outer leg 4 is not the only leg that can produce an inward yaw torque, its major role in modulating the yaw torque suggests that there may be a specific, centrally generated control of outer leg 4 during curve walking in crayfish.

Push enteroscopy in celiac sprue and refractory sprue

BACKGROUND

The aim of this study was to determine in patients with sprue whether jejunal endoscopy improves the diagnostic yield or provides information that may modify management, when compared with evaluation limited to the duodenum.

METHODS

From January 1994 to June 1998, a total of 31 patients (6 men, 25 women, mean age 41 years) were prospectively evaluated by push enteroscopy. They were divided into two groups: (1) celiac disease at different stages of activity (n = 23) and (2) refractory sprue (n = 8). The endoscopic and histologic findings in the duodenum and in the jejunum were compared.

RESULTS

Celiac disease: In 19 patients, endoscopic and histologic findings in the duodenum and jejunum were similar; in four patients villous atrophy was more severe in the duodenum than in the jejunum. Refractory sprue: In 5 of 8 patients, enteroscopy revealed ulcerative jejunitis, whereas ulcerations were found in the duodenum in only one case.

CONCLUSION

In refractory sprue, push enteroscopy with jejunal biopsies was of diagnostic value in 50% of cases demonstrating ulcerative jejunitis, whereas it did not modify the management of patients with responsive celiac disease.

Use of monetary reinforcers by cocaine-dependent outpatients

Monetary reinforcers have not been widely used as contingent reinforcers in the treatment of drug abuse, despite their demonstrated effectiveness. This is primarily due to concern that drug abusers will use monetary reinforcers to procure drugs. The present study addressed this concern by examining 48 cocaine-dependent outpatients' biweekly self-reports of how they used their earned reinforcers. For each subject, their reinforcement usage was classified into 12 higher-order categories and 34 subcategories. Usage proportions were calculated for each. Results indicated that monetary reinforcers were used very infrequently to acquire drugs or alcohol (2%). Reinforcers were used primarily for daily life activities (25%) (e.g., food and gas), money-related uses (18%) (e.g., savings and repaying debts), personal use (15%) (e.g., cosmetics and clothes), and household items (11%) (e.g., rent and bills). These findings challenge the concern that drug abusers use monetary reinforcers to purchase drugs and have important implications for the use of contingent monetary reinforcers in treatment settings.

Anderson's disease: exclusion of apolipoprotein and intracellular lipid transport genes

Anderson's disease is a rare, hereditary hypocholesterolemic syndrome characterized by chronic diarrhea, steatorrhea, and failure to thrive associated with the absence of apo B48-containing lipoproteins. To further define the molecular basis of the disease, we studied 8 affected subjects in 7 unrelated families of North African origin after treatment with a low-fat diet. Lipid loading of intestinal biopsies persisted, but the pattern and extent of loading was variable among the patients. Electron microscopy showed lipoprotein-like particles in membrane-bound compartments, the densities (0.65 to 7.5 particles/mu(2)) and the mean diameters (169 to 580 nm) of which were, in general, significantly larger than in a normal fed subject (0.66 particles/mu(2), 209 nm mean diameter). There were also large lipid particles having diameters up to 7043 nm (average diameters from 368 to 2127 nm) that were not surrounded by a membrane. Rarely, lipoprotein-like particles 50 to 150 nm in diameter were observed in the intercellular spaces. Intestinal organ culture showed that apo B and apo AIV were synthesized with apparently normal molecular weights and that small amounts were secreted in lipid-bound forms (density <1.006 g/mL). Normal microsomal triglyceride transfer protein (MTP) and activity were also detected in intestinal biopsies. Segregation analyses of 4 families excluded, as a cause of the disease, significant regions of the genome surrounding the genes for apo AI, AIV, B, CI, CII, CIII, and E, as were the genes encoding 3 proteins involved in intracellular lipid transport, MTP, and fatty acid binding proteins 1 and 2. The results suggest that a factor other than apoproteins and MTP are important for human intestinal chylomicron assembly and secretion.

[Anti-rotavirus vaccinations]

Rotavirus is the most common cause of severe acute diarrhea, responsible for 30 to 40 deaths of children each year in France. In order to decrease both mortality and morbidity, vaccines have been designed first from attenuated bovine strains, then from monovalent simian strains, and more recently from reassortant rhesus strains. The live tetravalent human-rhesus reassortant vaccine (RRT-TV) has been shown to be protective in the United States, Finland, and Venezuela despite different environments, in prospective double-blind studies. This vaccine, as the natural infection, decreases by 50% the risk of acute rotavirus diarrhea and by 70 to 100% the risk of severe diarrhea with dehydration. At the present time, its cost limits its use to developed countries. It was put on the market in the United States in October 1998. The challenge is now to make it available in developing countries.

Multimodal convergence of presynaptic afferent inhibition in insect proprioceptors

In the leg motor system of insects, several proprioceptive sense organs provide the CNS with information about posture and movement. Within one sensory organ, presynaptic inhibition shapes the inflow of sensory information to the CNS. We show here that also different proprioceptive sense organs can exert a presynaptic inhibition on each other. The afferents of one leg proprioceptor in the stick insect, either the position-sensitive femoral chordotonal organ or the load-sensitive campaniform sensilla, receive a primary afferent depolarization (PAD) from two other leg proprioceptors, the campaniform sensilla and/or the coxal hairplate. The reversal potential of this PAD is about -59 mV, and the PAD is associated with a conductance increase. The properties of this presynaptic input support the hypothesis that this PAD acts as presynaptic inhibition. The PAD reduces the amplitude of afferent action potentials and thus likely also afferent transmitter release and synaptic efficacy. These findings imply that PAD mechanisms of arthropod proprioceptors might be as complex as in vertebrates.

Correlation analysis between frequencies of circulating antigen-specific IgG-bearing memory B cells and serum titers of antigen-specific IgG

Recent studies in mice have indicated that the long-lasting specific antibody responses seen after vaccination are probably due to the existence of long-lived plasma cells. Therefore, because the maintenance of humoral immunity does not necessarily reflect continuous restimulation of long-lived memory B cells, the question arises as to what degree antibody immunity, as determined by measuring serum immunoglobulin titers against a particular antigen, and memory B cell immunity, as determined by counting circulating memory B cells with specificity for that same antigen, correlate. Here, using a new assay combining two-step immunomagnetic enrichment with multiparameter flow cytometry to detect, enumerate and characterize antigen-specific memory B cells, we show for tetanus toxin C-fragment in blood of normal tetanus toxoid vaccinized donors, and for wasp venom phospholipase A1B in blood of wasp venom-allergic donors undergoing an immune therapy with wasp venom, that there is no statistically significant linear correlation between the frequencies of circulating antigen-specific IgG-bearing memory B cells and the serum titers of antigen-specific IgG. This lack of a statistically significant linear correlation is in accordance with the idea that B memory cells and plasma cells represent independently controlled forms of immunological memory.

Behavioral and emotional problems among children of cocaine- and opiate-dependent parents

OBJECTIVE

To test associations between parental drug abuse and children's problems, children of cocaine- and opiate-dependent parents were compared with demographically matched referred and nonreferred children.

METHOD

Cocaine- and opiate-dependent parents in treatment completed the Child Behavior Checklist for 410 children (218 boys, 192 girls) from ages 2 through 18 years (mean = 7.9 years). Children of drug abusers (CDAs) were demographically matched to referred (RCs) and nonreferred children (NRCs).

RESULTS

RCs scored lower than CDAs and NRCs on most competence scales, and higher than CDAs and NRCs on all problem scales. CDAs scored lower than NRCs on most competence scales, and higher than NRCs on Withdrawn, Thought Problems, Delinquent Behavior, Aggressive Behavior, Internalizing, Externalizing, and Total Problems. Group status also predicted clinical range scores on most competence and all problem scales.

CONCLUSIONS

CDAs showed more internalizing and externalizing psychopathology relative to matched NRCs, but they showed significantly less psychopathology than shown by matched RCs. CDAs are an important group to target for preventive interventions.

Can NSAID/ASA-induced erosions of the gastric mucosa be identified at histology?

Studies in animals have shown that NSAID/ASA-induced erosions have an ischaemic pathogenesis. We therefore studied the question of whether such erosions in human gastric biopsy material can be identified on the basis of the ischaemic necrosis. Histological sections prepared from forceps biopsy material obtained from 122 patients with erosions (at least three biopsy specimens from the erosion and two from antrum and corpus each) were classified by a pathologist blinded to the endoscopic findings and the medication used by the patients. NSAID/ASA erosions were diagnosed when a homogeneous eosinophilic ischaemic necrosis blending into the adjoining lamina propria presented. Helicobacter pylori (Hp)-induced erosions were diagnosed when, in the presence of Hp gastritis, erosive defects were covered with a non-homogeneous fibrinoid necrosis containing granulocytes and cell debris. Finally, the histological classification was compared with data on medication usage. The histological diagnosis was Hp-induced erosions in 59 patients, NSAID/ASA-induced erosions with no Hp gastritis in 23, and NSAID/ASA-induced erosions with concomitant Hp gastritis in 40. A comparison of this histological classification with the data provided by the referring physicians on patient medication revealed that 70% of the patients with histological diagnosis of NSAID/ASA-induced erosions in the absence of Hp gastritis, and 65% of those diagnosed to have NSAID/ASA-induced erosions and concomitant Hp gastritis, had been taking such drugs. Among the erosions diagnosed as H. pylori-induced, 81% of the patients were reported not to take such medication. The sensitivity of the diagnosis of NSAID/ASA-induced erosions was 72.9%, and specificity 79.6%. The results of the present study show that a high percentage of the NSAID/ASA-induced erosions of the gastric mucosa can indeed be correctly diagnosed at histology.

Activation of the protein tyrosine phosphatase SHP2 via the interleukin-6 signal transducing receptor protein gp130 requires tyrosine kinase Jak1 and limits acute-phase protein expression

Stimulation of the interleukin-6 (IL-6) signalling pathway occurs via the IL-6 receptor-glycoprotein 130 (IL-6R-gp130) receptor complex and results in the regulation of acute-phase protein genes in liver cells. Ligand binding to the receptor complex leads to tyrosine phosphorylation and activation of Janus kinases (Jak), phosphorylation of the signal transducing subunit gp130, followed by recruitment and phosphorylation of the signal transducer and activator of transcription factors STAT3 and STAT1 and the src homology domain (SH2)-containing protein tyrosine phosphatase (SHP2). The tyrosine phosphorylated STAT factors dissociate from the receptor, dimerize and translocate to the nucleus where they bind to enhancer sequences of IL-6 target genes. Phosphorylated SHP2 is able to bind growth factor receptor bound protein (grb2) and thus might link the Jak/STAT pathway to the ras/raf/mitogen-activated protein kinase pathway. Here we present data on the dose-dependence, kinetics and kinase requirements for SHP2 phosphorylation after the activation of the signal transducer, gp130, of the IL-6-type family receptor complex. When human fibrosarcoma cell lines deficient in Jak1, Jak2 or tyrosine kinase 2 (Tyk2) were stimulated with IL-6-soluble IL-6R complexes it was found that only in Jak1-, but not in Jak 2- or Tyk2-deficient cells, SHP2 activation was greatly impaired. It is concluded that Jak1 is required for the tyrosine phosphorylation of SHP2. This phosphorylation depends on Tyr-759 in the cytoplasmatic domain of gp130, since a Tyr-759-->Phe exchange abrogates SHP2 activation and in turn leads to elevated and prolonged STAT3 and STAT1 activation as well as enhanced acute-phase protein gene induction. Therefore, SHP2 plays an important role in acute-phase gene regulation.

Sociality and the rate of rDNA sequence evolution in wasps (Vespidae) and honeybees (Apis)

Sequence data of mitochondrial 16S ribosomal DNA (mt-rDNA) and nuclear 28S ribosomal DNA (nuc-rDNA) were compared in two honeybee species (Apis mellifera and Apis dorsata) and a selection of 22 wasp species (Vespidae) with different levels of sociality. The averge substitution rates in mt-rDNA and nuc-rDNA were almost-equal in solitary species. In species with larger nests, however, the difference between the nuclear and the mitochondrial substitution rate significantly increased. The average substitution ratio, psi (nucleotide substitutions in mt-rDNA/nucleotide substitutions in nuc-rDNA) was 1.48 +/- 0.12 (SE) among the solitary Eumeninae, 3.70 +/- 0.15 among five primitive social Stenogastrinae species, 3.24 +/- 0.20 among five Polistinae species, 5.76 +/- 0.33 among nine highly eusocial Vespinae, and 12.7 in the two Apis species. The high egg-laying rate and the effective population size skew between the sexes may contribute to the rise of the substitution ratio in the highly eusocial species. Drift and bottleneck effects in the mitochondrial DNA pool during speciation events as well as polyandry may further enhance this phenomenon.

Commitment of individual Th1-like lymphocytes to expression of IFN-gamma versus IL-4 and IL-10: selective induction of IL-10 by sequential stimulation of naive Th cells with IL-12 and IL-4

Commitment of Th lymphocytes to the Th1 phenotype, as characterized by the expression of the major proinflammatory cytokine IFN-gamma, may be critically involved in the establishment of chronic inflammation and inflammatory autoimmune disease. To date, it has been shown that in IL-12-stimulated murine Th cell lines containing a major fraction of Th1 cells, Th2 cells can be induced by IL-4 until about 2 wk after initial activation, but not later. Here we analyze, based on the magnetic isolation of viable Th1 cells according to their specific expression of IFN-gamma, the cytokine commitment of individual Th1 cells. After activation of naive Th cells with Ag and IL-12 for up to 5 wk, isolated IFN-gamma-producing cells were restimulated with Ag and IL-4. Within the first 3 to 4 wk of IL-12 stimulation, some IFN-gamma+ cells stopped expression of IFN-gamma when restimulated with IL-4. However, within only 1 to 2 wk of IL-12 stimulation, few IFN-gamma+ cells could be converted to produce IL-4. Others continued to express IFN-gamma and thus were already committed to a proinflammatory, Th1-like phenotype. Surprisingly, within 3 wk of IL-12 stimulation, many of the IFN-gamma-producing cells responded to IL-4 restimulation by expression of IL-10, but neither IFN-gamma nor IL-4, i.e., by conversion to a suppressive, anti-inflammatory phenotype.

CTLA-4 gene polymorphism is associated with predisposition to coeliac disease

BACKGROUND

Susceptibility to coeliac disease is strongly associated with particular HLA class II alleles. However, non-HLA genetic factors are likely to be required for the development of the disease. Among candidate genes is the CTLA-4 (cytotoxic T lymphocyte associated) gene located on chromosome 2q33 in humans, which encodes a cell surface molecule providing a negative signal for T cell activation.

AIMS

To investigate CTLA-4 exon 1 polymorphism (position 49 A/G) in patients with coeliac disease.

PATIENTS

101 patients with coeliac disease and 130 healthy controls.

METHODS

Allele specific hybridisation and restriction enzyme digestion of polymerase chain reaction amplified genomic DNA.

RESULTS

The A allele of the CTLA-4 position 49 polymorphism was found on 82.2% of chromosomes in patients with coeliac disease compared with 65.8% in controls (p < 0.0001), mostly in the homozygous form (68.3% in patients versus 47.7% in controls; odds ratio (OR) 2.36, 95% confidence interval (CI) 1.37 to 4.06, p = 0.002). Four patients only had the G/G genotype compared with 21 controls (OR 0.21, CI 10.07 to 0.64, p = 0.002). These differences were maintained when subjects were stratified according to the HLA class II phenotype, in particular when patients and controls were matched for the presence of the predisposing HLA DQB1*02 (DQ2) allele or HLA-DQA1*0501/DQB1*02 heterodimer.

CONCLUSION

The CTLA-4 gene polymorphism is a non-HLA determinant that predisposes to coeliac disease. Whether it directly contributes to disease susceptibility or represents a marker for a locus in linkage disequilibrium with CTLA-4 needs further investigation.

Simulation of complex movements using artificial neural networks

A simulated network for controlling a six-legged, insect-like walking system is proposed. The network contains internal recurrent connections, but important recurrent connections utilize the loop through the environment. This approach leads to a subnet for controlling the three joints of a leg during its swing which is arguably the simplest possible solution. The task for the stance subnet appears more difficult because the movements of a larger and varying number of joints (9-18: three for each leg in stance) have to be controlled such that each leg contributes efficiently to support and propulsion and legs do not work at cross purposes. Already inherently non-linear, this task is further complicated by four factors: 1) the combination of legs in stance varies continuously. 2) during curve walking, legs must move at different speeds, 3) on compliant substrates, the speed of the individual legs may vary unpredictably, and 4) the geometry of the system may vary through growth and injury or due to non-rigid suspension of the joints. This task appears to require some kind of "motor intelligence". We show that an extremely decentralized, simple controller, based on a combination of negative and positive feedback at the joint level, copes with all these problems by exploiting the physical properties of the system.

Sequential production of IL-2, IFN-gamma and IL-10 by individual staphylococcal enterotoxin B-activated T helper lymphocytes

Upon primary activation, T helper (Th) cell populations express different cytokines transiently and with different kinetics. Stimulation of naive murine splenic Th cells with the bacterial superantigen Staphylococcus aureus enterotoxin B (SEB) in vitro results in expression of IL-2, IFN-gamma and IL-10 with fast, intermediate and slow kinetics, respectively. This first report of a functional analysis of cells separated alive according to cytokine expression shows that these cytokines are not produced by different Th cell subpopulations, but can be expressed sequentially by individual Th cells. Th cells, activated with SEB for 1 day and isolated according to expression of IL-2, using the cellular affinity matrix technology, upon continued stimulation with SEB later secrete most of the IFN-gamma and IL-10. Likewise, after 2 days of SEB culture, cells expressing IFN-gamma, separated according to specific surface-associated IFN-gamma as detected by magnetofluorescent liposomes, 1 day later secrete IL-10. Thus, individual Th1 cells can contribute to the control of their own IFN-gamma expression by sequential expression of first IL-2, supporting their proliferation, and later IL-10, down-regulating the production of IFN-gamma-inducing monokines and limiting the pro-inflammatory effects of IFN-gamma.

Molecular phylogeny of Vespidae (Hymenoptera) and the evolution of sociality in wasps

The oriental Stenogastrinae is a group in which there is considerable interest as regards the study of evolution of sociality in wasps, because they show broad diversity in social behavior. Using cladistic analysis on morphological and behavioral data, they have been grouped together with the social Vespinae and Polistinae in the family of Vespidae. This is not without dispute, because several other morphological and behavioral characters separate Stenogastrinae from the other Vespidae subfamilies. DNA sequences were obtained from nuclear 28S ribosomal DNA and the mitochondrial 16S ribosomal DNA of two Apis species and nine social and three solitary wasp species of the family Vespidae. Solitary wasps of the family Braconidae and Pteromalidae were used as outgroups. Parsimony, distance, and maximum-likelihood methods of both mitochondrial and nuclear DNA did not support the conventional phylogenetic position of Stenogastrinae. In all phylogenetic reconstructions, the solitary Eumeninae were a sister taxon to the Polistinae + Vespinae cluster. The analyzed sequences provide strong evidence that sociality has independently evolved twice in the Vespidae.

Effects of nicotine on methadone self-administration in humans

The effects of nicotine abstinence, ad libitum smoking, and 0, 2, and 4 mg nicotine gum on methadone self-administration were investigated. Five methadone-maintained patients with a history of smoking (18-30 cigarettes/day) were recruited as subjects. Upon arrival expired carbon monoxide levels were measured to confirm self-reported abstinence of 10-12 h. At 30 min prior to the methadone self-administration session, two response options were concurrently available. When a 64-button press requirement (FR64) was completed, 10 ml of 0.054 mg/ml methadone solution, or vehicle, was delivered. Immediately following, and 30, 60, 90, and 120 min after the self-administration session, expired carbon monoxide levels and typical symptoms of nicotine withdrawal were assessed. Relative to abstinence, subjects consumed more methadone following the 4-mg nicotine gum and ad libitum smoking conditions. Ratings of cigarette craving were significantly less following ad libitum smoking or administration of 4-mg nicotine gum, than following abstinence. Implications for understanding opioid and nicotine interactions are discussed.

Immunomagnetic enrichment of disseminated epithelial tumor cells from peripheral blood by MACS

Disseminated epithelial tumor cells have been detected in the bone marrow and blood of cancer patients by means of immunocytochemical or immunofluorescent staining of cytocentrifuge slides, multiparameter flow cytometry, and reverse transcriptase-polymerase chain reaction. However, it is hardly possible using such methods to detect tumor cells at a frequency below 10(-6). To increase the sensitivity of these detection techniques we have developed a new technology for the enrichment of disseminated epithelial tumor cells from hematopoietic cell samples by high-gradient magnetic cell sorting (MACS). Cells are permeabilized and fixed and carcinoma cells are magnetically labeled specifically with an anti-cytokeratin 8 monoclonal antibody (mAb) directly conjugated to superparamagnetic microbeads. Magnetically labeled cells are enriched on high-gradient magnetic columns. Tumor cells are detected in the enriched cell fraction by flow cytometry, fluorescence microscopy, or immunocytochemisty. In this study we demonstrated the method using a model system in which five to 5,000 cells from a breast cancer cell line were seeded into blood cell samples from a healthy donor containing 1.2 x 10(8) leukocytes. Tumor cells were 10,477+/-4242 (n=25)-fold magnetically enriched, and 57.7%+/-16.9% (n=33) of the initially seeded tumor cells were recovered. Applying the method to 20-40 mL blood samples from patients with advanced carcinomas of the breast, prostate, colon, rectum, or lung, we were able to detect between one and 6.8 x 10(4) cytokeratin-expressing tumor cells in 21 of 34 patients. This corresponds to frequencies of tumor cells between 6.8 x 10(-9) and 1.1 x 10(-3) among nucleated cells in the original sample. Enriched tumor cells were further analyzed for expression of tissue-specific and prognostic markers such as breast mucin glycoproteins, erbB2, and CD44v6 for additional characterization and to confirm their tumor origin. The technique described could become a valuable tool for the quantification and molecular characterization of metastatic carcinoma cells in hematopoietic tissue, and may ultimately prove useful in the diagnosis, prognosis, and monitoring of patients with carcinoma.

Baseline assessment, study entry, and stabilization: double-blind clinical trials in drug dependence

To summarize, perhaps most important, but most difficult to achieve will be commonalties and standardization across trials so that rigorous comparison is possible. Researchers will do well to examine clinical trials in other areas, mimicking those elements that are compatible, avoiding those that are not, and above all, avoiding costly reinvention.

Syndrome of intractable diarrhoea with persistent villous atrophy in early childhood: a clinicopathological survey of 47 cases

BACKGROUND

The syndrome of intractable diarrhoea of infancy is heterogeneous and includes several diseases with diverse aetiologies. This study determines whether diagnostic categories can be defined on the basis of clinicopathological analysis.

METHODS

European Society of Paediatric Gastroenterology, Hepatology and Nutrition members were surveyed to identify cases of intractable diarrhoea with persisting small intestinal enteropathy. A retrospective clinicopathological analysis was performed on cases showing life-threatening diarrhoea within the first 24 mo of life and requiring total parenteral nutrition, which were characterized by persistent villous atrophy, and resistance to therapy.

RESULTS

Forty-seven infants were identified with intractable diarrhoea. Villous atrophy was of varying degrees with (group I, n = 24) or without (group II, n = 18) lamina propria mononuclear cell infiltration. Group I presented later, had gut autoantibodies, and a higher prevalence of protein-losing enteropathy; a subset (group Ia, n = 12) also had extraintestinal symptoms of autoimmunity associated with a later onset of larger volume diarrhoea. Group II presented early; 8 cases (group IIa) had phenotypic abnormalities and a low birth weight; the remaining 10 (group IIb) showed mild-to-moderate villous atrophy, epithelial tufting, and abnormal crypts. Group III included five patients in whom no specific features were recognised. Twenty-one (45%) died at a median age of 24 months, 20 (43%) remained dependent on parenteral (n = 16) or enteral tube (n = 4) feeding, 4 (9%) received elimination diets plus other therapies, and 2 (4%) were lost to follow-up.

CONCLUSIONS

Clinicopathological analysis allowed distinct disease groups to be identified, allowing a provisional classification to be made. This straightforward approach forms a basis for future research in this exceptionally difficult paediatric condition.

Cue reactivity in cocaine-dependent subjects: effects of cue type and cue modality

Thirty cocaine-dependent subjects were enrolled into a cue-laboratory study to determine the specificity and sensitivity of this paradigm as a craving measure. Subjects experienced three cue types (i.e., cocaine, arousing, and neutral stimuli) in three cue modalities (i.e., audio, visual, and manual). Cue types were administered in different experimental sessions with a period of 2 to 3 days between sessions. Our results showed that subjective and physiological craving for cocaine was relatively specific for the cocaine cue as compared with either the arousing or the neutral cue. The relative sensitivities of the cue modalities in decreasing order was manual, audio, and visual. We suggest that a modified conditioned-cue paradigm could be a useful tool in the repeated assessment of craving during a clinical study.

Retention, HIV risk, and illicit drug use during treatment: methadone dose and visit frequency

OBJECTIVES

This study examined two major methadone treatment factors, visit frequency and methadone dose, posited to be important in reducing intravenous drug use and human immunodeficiency virus (HIV) transmission.

METHODS

One hundred fifty opiate-dependent subjects randomly assigned to four groups received 50 or 80 mg of methadone and attended a clinic 2 or 5 days per week.

RESULTS

Survival analysis indicated higher dropout rates for groups having five vs two visits per week (Chi2[1]=7.76). Higher proportions of opiate-positive results on urine screens were associated with lower methadone doses (F[1,91]=4.74).

CONCLUSIONS

Receiving take-home doses early in treatment enhanced treatment retention. The 50-mg dose combined with five visits per week produced the worst outcome. Fewer visits enhanced retention at 50 mg, but opiate use rates were higher at this dose than they were for either 80-mg group. The HIV infection rate at entry was 9%. No subjects seroconverted during the study. Risk behaviors for acquired immunodeficiency syndrome declined over time regardless of group/dose assignment. These results have important implications for modification of regulatory and clinic policy changes.

Ritanserin in the treatment of cocaine dependence

Sixty-five cocaine-dependent subjects were enrolled into a 10-week randomized, double-blind study to determine the safety and efficacy of the serotonin-2 receptor antagonist, ritanserin (10 mg/day), in reducing cocaine consumption and craving. All subjects also participated in a structured intensive outpatient psychosocial program. Seventy-three percent of the participants completed the treatment program and follow-up. Subjects experienced a significant reduction in craving: 66.4% and 32.5% for the placebo and ritanserin groups, respectively. These reductions in craving were not paralleled by substantial decreases in cocaine use. Self-reported cocaine use was less frequent in the placebo group; paradoxically, blood levels of its metabolite, benzoylecgonine, were also higher although insignificantly so. Generally, ritanserin was well tolerated but significantly prolonged the QTc interval on the electrocardiogram. This outpatient program is effective at maintaining cocaine-dependent individuals in treatment and reducing craving. Ritanserin (10 mg/day) is not an efficacious adjunct to psychosocial treatment for cocaine dependence.

In situ localization of the putative movement protein (pr17) from potato leafroll luteovirus (PLRV) in infected and transgenic potato plants

The potato leafroll virus (PLRV) 17-kDa protein (pr17), the putative movement protein for this phloem-limited luteovirus, was localized on ultrathin sections of leaves from PLRV-infected and transgenic potato plants. The transgenic plants expressed the entire viral genome from a full-length cDNA copy (PLRVfl) or only the gene encoding pr17 (ORF4) under the control of the cauliflower mosaic virus 35S promoter. Virus-infected and PLRVfl-transgenic plants developed symptoms typical of virus infection, whereas pr17-transgenic plants did not display symptoms or ultrastructural alterations. Immunogold electron microscopy using an anti-pr17-serum detected pr17 in plasmodesmata, in virus-induced vesicles, in mitochondria, and in chloroplasts of phloem cells, in PLRV-infected as well as PLRVfl-transgenic plants. In addition, in transgenic plants, pr17 was expressed in mesophyll cells (which are not infected by PLRV under natural conditions) and localized to the same sites as in phloem cells, except in plasmodesmata. In contrast, in pr17-transgenic plants the protein was never observed on organelles, but was almost exclusively associated with plasmodesmata of all leaf cell types, indicating that the targeting of pr17 to plasmodesmata is an intrinsic property of the protein. These results support the role of pr17 in PLRV movement.

Receptors for carbohydrate ligands including heparin on the cell surface of Leishmania and other trypanosomatids

By employing neoglycoproteins (NGP) and glycosaminoglycans, the detection of endogenous glycoligand-binding sites has become possible. Monitoring specific binding of 11 of these sugar receptor-specific tools, 13 trypanosomatids of monogenetic genera Blastocrithidia, Crithidia, Herpetomonas, and Leptomonas and digenetic genera Endotrypanum, Leishmania, and Sauroleishmania were analysed by agglutination and fluorescence assays. NGP showed agglutination reactions only with the digenetic but not with the monogenetic species. Sensitive flow cytofluorimetric investigations revealed that the apparently different reactivity to NGP is due to a pronounced quantitative difference in expression of binding sites between mono- and digenetic flagellates. Moreover, flow cytofluorimetry was used to demonstrate the occurrence of receptor sites for heparin on the cell surfaces of all trypanosomatids. An indication for a correlation of the binding capacity for the NGP N-acetyl-beta-D-glucosamine and heparin to differences in the pathogenicity of parasites was observed for Leishmania donovani as well as Leishmania enriettii. Infective populations of these species contained a significantly higher number of cells which had bound N-acetyl-beta-D-glucosamine and heparin than noninfective (long-term in vitro-cultured) populations. The results of the present report additionally support the hypothesis that lectin-carbohydrate interactions with neutral sugar moieties and heparin or heparin-like molecules participate in the interactions between trypanosomatids and host (cells), and that the detected binding sites for carbohydrates and heparin may thus be referred to as potential virulence factors.

Germinal centre CD4+ T cells are an important site of HIV replication in vivo

OBJECTIVE

CD4+ T cells are the main target for HIV. However, the highest HIV antigen concentration in infected subjects accumulates on the cell surface of follicular dendritic cells in the germinal centres of the lymphoid tissue. Germinal centres contain a T-helper cell subset which expresses CD57 molecules. Here we analysed virus replication and viral load in CD57+CD4+ germinal centre T cells and in the CD4+ T cells found mostly outside germinal centres (CD57-CD4+).

METHODS

Peripheral blood mononuclear cells and lymph-node cells were prepared, stained for CD4 and CD57 and purified by FACS. Defined cell numbers of CD4+CD57+ cells and CD4+CD57- cells were sorted directly into polymerase chain reaction (PCR) tubes by FACS, equipped with an automated cell deposition unit and analysed by PCR to detect proviral DNA. Based on Poisson distribution, the expected level of infection was calculated. Viral replication was determined by amplifying double-spliced, single-spliced, and full-length transcripts of HIV using serially diluted cDNA of the FACS-sorted cells.

RESULTS

An up to 10-fold higher frequency of infected cells was found in the CD57+CD4+ germinal centre T cells compared with CD57-CD4+ T cells. Furthermore, active viral replication was detected almost exclusively in the CD57+CD4+ T cells.

CONCLUSIONS

The CD57+CD4+ germinal centre T cells are one of the sites of HIV infection and replication that may play a pivotal role in the pathogenesis of HIV infection.

CD45RA-expressing memory/effector Th cells committed to production of interferon-gamma lack expression of CD31

It has been considered before that human naive and memory/effector CD4+ T-cells cannot be subdivided solely according to the differential expression of CD45 isoforms. By the lack of expression of CD31 we have identified a subset of CD4+ CD45RA+ CD31- cells which show distinct features of antigen-experienced Th1 cells. Short term stimulation of highly purified human peripheral blood CD4+ T-cells with PMA/ionomycin, followed by the cytometric analysis of intracellular cytokines, showed that a minor subpopulation of CD4+ CD45RA+ CD45RO- cells is able to produce interferon-gamma (IFN-gamma) rapidly, a characteristic of antigen-experienced Th1 cells. Whereas among CD45RA+ CD4+ T-cells both CD31+ and CD31- subsets produce interleukin-2 (IL-2) upon PMA/ionomycin stimulation, only the CD31- subpopulation is able to produce IFN-gamma. Thus, our phenotypic and functional characterization of CD45RA+ CD45RO- Th cells shows that CD45RA+ CD45RO- cells do not represent a homogeneous population of antigen-unexperienced, naive T-cells. We speculate that a certain subset of human CD4+, CD45RO+ memory T-cells reverts to expression of the CD45RA isoform, and that this subset can be identified by the lack of CD31 expression.

Histopathology and microbiology of isolated rectal bleeding in neonates: the so-called 'ecchymotic colitis'

Rectal bleeding in neonates is an alarming event which suggests a possible necrotizing enterocolitis (NEC) but is usually the only symptom of an unexplained colitis characterized endoscopically by ecchymotic mucosal lesions, the so-called 'ecchymotic colitis' (EC). We studied histologically and bacteriologically 18 infants (mean age: 18 days) presenting with rectal bleeding by systematic rectosigmoidoscopy and intestinal biopsies. The 18 infants were hospitalized. Prematurity was found in seven cases and an underlying condition in 14 cases (respiratory distress: six cases; infection: six cases; surgery: two cases). Histology showed a mild to moderate inflammation (10/12) of the mucosa with a prevalence of polymorphonuclear cells (8/10), frequent focal haemorrhages (11/12) and foci of pneumatosis (4/12). Numerous bacteria were seen in the mucus layer focally forming large clusters. Cultures of intestinal biopsies yielded exclusively Enterobacteriaceae species: Escherichia coli (seven cases), Klebsiella spp. (seven cases), and Enterobacter cloacae (three cases); four cases were sterile. Our study demonstrates that neonatal bleeding is associated with endoscopic and histological 'ecchymotic colitis' lesions and with a peculiar microbial flora of EBC strains. EC and necrotizing enterocolitis share similar features raising the question of the link between the two syndromes.

In vivo expression of a full-length cDNA copy of potato leafroll virus (PLRV) in protoplasts and transgenic plants

A full-length cDNA copy (PLRVfl) of potato leafroll virus (PLRV) was constructed and examined in vivo for its biological activities by transient expression experiments with plasmid DNA or in vitro transcribed RNA. In addition, PLRVfl cDNA was stably introduced into the genome of potato plants by Agrobacterium-mediated leaf disc transformation. Both transient and stable expression of PLRVfl resulted in the synthesis of genomic and subgenomic PLRV RNAs. Transgenic plants accumulated the 17-kDa movement protein and displayed the typical symptoms of PLRV infection. This is the first example of the constitutive expression of a phloem-limited virus in planta.

[Familial adenomatous polyposis and thyroid cancer]

Familial adenomatous polyposis may exhibit extracolonic tumors which include thyroid carcinoma. It has been recently suggested that thyroid carcinomas associated with familial adenomatous polyposis show distinct histologic features different from sporadic follicular or papillary thyroid carcinomas. We report a case of thyroid carcinoma in a young girl affected by familial adenomatous polyposis, whose thyroid tumor exhibited some of these features. This finding confirms the peculiar histologic phenotype of the thyroid carcinomas associated with familial adenomatous polyposis. Alterations of the APC gene responsible for familial adenomatous polyposis may play a role in the development of these thyroid cancers.

Magnetic resonance imaging for diagnosis of Shwachman's syndrome

Shwachman's syndrome is a rare disease characterized by the association of chronic diarrhea due to exocrine pancreatic insufficiency, metaphyseal dysostosis, and neutropenia. The diagnosis requires demonstration of lipomatosis, or fatty replacement of the pancreas, which is the typical pathological feature of the disease. Magnetic resonance imaging (MRI) was performed in 13 patients with exocrine pancreatic insufficiency, 7 with Shwachman's syndrome, 2 with Pearson's syndrome, 1 with normal sweat test later diagnosed as cystic fibrosis, and 3 without identified syndrome, and in 7 control children. Ultrasonography in the patients did not differentiate between atrophy and lipomatosis and could not be performed in 3. MRI visualized the pancreas in all. The same image was noted in all patients with Shwachman's syndrome with a normal-sized or enlarged pancreas, a hyperintense signal on T1- and T2-weighted image, and a null signal on short time inversion recovery (STIR)-weighted image, characteristic of fat. In all other patients, the findings were very different: The pancreas was a small structure surrounded with fat. In 1 patient without identified syndrome, the pancreas appeared to be partially replaced with fat. MRI is an excellent imaging technique to correlate the nature of a tissue and its radiological representation, especially fat, which gives a very typical signal. In our brief series of patients with Shwachman's syndrome, MRI had 100% positive predictive value in demonstrating lipomatosis. In atypical cases of pancreatic insufficiency in which some of the clinical features of Shwachman's syndrome are absent. MRI is an invaluable aid in the diagnostic procedure.

Premotor interneurons in generation of adaptive leg reflexes and voluntary movements in stick insects

We investigated the role of local nonspiking interneurons involved in motor control of legs in the stick insects, Carausius morosus. In a preparation that allowed the animals to perform active leg movements such as adaptive tactile reflexes, proprioceptive reflexes, and walking, we gathered the following results. Almost all tested nonspiking interneurons that provide synaptic drive onto moto-neurons of the proximal leg muscles contribute to all of the motor programs underlying tactile reflexes and voluntary leg movements such as walking, searching, and rocking. Most of them are also involved in the generation of proprioceptive reflexes. All motor programs for coactivation, avoidance reflexes, resistance reflexes, and voluntary leg movements result from parallel pathways including nonspiking interneurons that support and others that oppose the motoneuronal activity. The contribution of a single interneuron to the different motor program is specific: it can be supporting for one motor program but opposing for the other. Even for the same motor program, for example, coactivation, the contribution of an individual interneuron can depend on the stimulus site from where the response is elicited. Our results support the idea that the different motor patterns for adaptive tactile reflexes, resistance reflexes, and voluntary leg movements emerge from a multifunctional neuronal circuit that is reorganized corresponding to the motor behavior performed. The actual motor pattern is then shaped by distributed information processing in parallel supporting and opposing pathways.

Is celiac disease a lifelong disorder?

That celiac disease is a lifelong disorder was suggested by clinical case records and was considered to have been demonstrated through the widespread use of intestinal biopsies by the end of the 1950s. It was clear that the mucosal lesions observed in children and adults were identical and responded similarly to gluten withdrawal. In fact, in 1970 the European Society for Paediatric Gastroenterology and Nutrition instituted the practice of a challenge after diagnosis. A relapse of clinical symptoms and of the intestinal lesions after gluten was reintroduced into the diet demonstrated the "permanent" nature of sensitivity to gluten in children with celiac disease. Twenty-five years later, the permanence of the sensitivity of the intestinal mucosa to gluten is again a matter of debate. Several lines of evidence, gathered during recent years, show that celiac disease is not always a lifelong condition. First, the long-term follow-up of children with proven celiac disease shows that 10% to 20% of them become "tolerant" (defined on clinical, biological and histologic grounds) to gluten during adolescence. Second, it has also been shown, in individual cases, that the mucosal lesions typical of the disease may appear during adulthood. Our increasing knowledge of the long-term evolution of the disease suggests that celiac disease develops and, in some cases, fades in a predisposed group of people with intestinal sensitivity to gluten, which is probably a common condition. The factors leading to the appearance or disappearance of the disease, however, are still unknown.

[Crataegus Special Extract WS 1442. Assessment of objective effectiveness in patients with heart failure (NYHA II)]

METHOD

In a multicenter, placebo-controlled double-blind study, the efficacy of the Crataegus-Specialextrakt WS 1442 in patients with NYHA stage II cardiac insufficiency was investigated. A total of 136 patients with this diagnosis were admitted to the study and, following a 2-week run-in phase, treated with Crataegus-Specialextract or placebo over a period of 8 weeks. The primary target parameter was the change in the difference of the pressure, heart rate product (systolic blood pressure x heart rate/100) (PHRP 50 W load vs. rest) measured at the beginning and end of treatment.

RESULTS

On the basis of this variable, a clear improvement in the performance of the heart was shown in the group receiving the test substance, while the condition of the placebo group progressively worsened. The therapeutic difference between the groups was statistically significant. The positive result for the objective efficacy parameter was confirmed by a statistically obvious superiority of Crataegus in the patient's own assessment of improvement in the main symptoms (reduced performance, shortness of breath, ankle edema etc.). In addition, active treatment led, in comparison with placebo, to a considerably better quality of life for the patient, in particular with respect to mental well-being. The tolerability of the active substance proved to be very good-as shown by comprehensive laboratory investigations and the recording of undesirable events.

CONCLUSION

All in all, the results of the present clinical investigation confirm those of previous studies showing that Crataegus-Specialextrakt WS 1442 is an effective and low-risk phytotherapeutic form of treatment in patients with NYHA II cardiac insufficiency.

Absence of primary association between DM gene polymorphism and insulin-dependent diabetes mellitus or celiac disease

The DMA and DMB genes encode class II-like heterodimetric molecules located in a specialized endocytic compartment, where they facilitate efficient loading of antigenic peptides on HLA class II molecules. Both genes are located within the MHC class II region and present a limited allelic polymorphism. Here we report the distribution of DM alleles in a group of 75 IDDM patients, 72 CD patients, and 162 random controls. We found a pronounced decreased frequency of DMA*0102 in both patient groups relative to controls. This difference was, however, mainly secondary to a strong negative linkage disequilibrium (LD) between this allele and the IDDM and CD-associated DRB1*03 allele. The DMB phenotype frequencies were similar in CD patients and controls. By contrast, we observed a decreased frequency of DMB*0101 and an increased frequency of DMB*0102 and DMB*0104 in IDDM patients. These differences disappeared when matching individuals for DRB1*03 or DRB1*04 alleles, which was in accordance with strong negative LD between DMB*0101 and DRB1*04 or DQB1*0302 alleles, and positive LD between DMB*0104 and DQB1*0201. Our data suggest that the apparent associations of IDDM or CD with given DM alleles are mostly secondary to primary associations with alleles at the DRB and DQB loci.

[Sleeping position, prevention of sudden death syndrome and gastroesophageal reflux]

Based on results of epidemiological studies, dorsal or lateral sleeping positions are now recommanded in the prevention of sudden infant death syndrome (SIDS). This raises an ethical question about the attitude towards the ventral positioning therapy for gastroesophageal reflux (GOR). The consensus conference considers that the ventral position should only be recommanded in GOR when the benefit appears to outweigh the risk of SIDS that it induces. The conference proposes that for infants with simple uncomplicated reflux, sleeping in the prone position should not be introduced in the first line treatment. Prone positioning should be restricted to complicated cases resistant to dietary and medical measures.