A simple clinical colitis activity index

Background—The appropriate medicaltreatment of patients with ulcerative colitis is determined largely bythe severity of symptoms. Hospital assessment of the severity ofdisease activity includes investigation of laboratory indices andsigmoidoscopic assessment of mucosal inflammation.
Aims—To develop a simplifiedclinical colitis activity index to aid in the initial evaluation ofexacerbations of colitis.
Methods—The information fordevelopment of the simple index was initially evaluated in 63 assessments of disease activity in patients with ulcerative colitiswhere disease activity was evaluated using the Powell-Tuck Index (whichincludes symptoms, physical signs, and sigmoidoscopic appearance). Thenew index was then further evaluated in 113 assessments in a differentgroup of patients, by comparison with a complex index utilisingclinical and laboratory data, as well as five haematological andbiochemical markers of disease severity.
Results—The newly devised SimpleClinical Colitis Activity Index, consisting of scores for five clinicalcriteria, showed a highly significant correlation with the Powell-TuckIndex (r=0.959, p<0.0001) as well as thecomplex index (r=0.924, p<0.0001) and alllaboratory markers (p=0.0003 to p<0.0001).
Conclusions—This new Simple ColitisActivity Index shows good correlation with existing more complexscoring systems and therefore could be useful in the initial assessmentof patients with ulcerative colitis.

Keywords:ulcerative colitis; disease activity

     

Construction of hybrid proteins that migrate retrogradely and transynaptically into the central nervous system

The nontoxic proteolytic C fragment of tetanus toxin (TTC peptide) has the same ability to bind nerve cells and be retrogradely transported through a synapse as the native toxin. We have investigated its potential use as an in vivo neurotropic carrier. In this work we show that a hybrid protein encoded by the lacZ–TTC gene fusion retains the biological functions of both proteins in vivo—i.e., retrograde transynaptic transport of the TTC fragment and β-galactosidase enzymatic activity. After intramuscular injection, enzymatic activity could be detected in motoneurons and connected neurons of the brainstem areas. This strategy could be used to deliver a biological activity to neurons from the periphery to the central nervous system. Such a hybrid protein could also be used to map synaptic connections between neural cells.     

Cytokine production in whole blood cell cultures of patients with rheumatoid arthritis

OBJECTIVE—The measurement of cytokine production of activated lymphocytes and monocytes in the whole blood cell (WBC) culture system may provide a sensitive tool for evaluating the actual ongoing immune response of patients with rheumatoid arthritis (RA).
METHODS—Lipopolysaccharide (LPS) up to 250 pg/ml was used for the stimulation of monocytes for measuring the production of tumour necrosis factor α (TNFα), interleukin 6 (IL6) and IL12, while the anti-CD3 (1 µg/ml) and anti-CD28 (5 µg/ml) combination was used for T cell stimulation with the measuring of IL4 and interferon gamma (INFγ) production. Twenty seven patients with RA and 23 healthy controls were studied.
RESULTS—The results showed a decreased IL6 (LPS stimulus 4-6 pg/ml) and IL12 (LPS stimulus 16-62 pg/ml) production in the RA patients. The maximal production of both cytokines was comparable with the normal controls. T cell stimulation showed a significant decreased INFγ production in the RA patients.
CONCLUSIONS—These findings obtained in the WBC culture system are highly suggestive for a decreased TH-1 derived cytokine production by a diminished IL12 production in RA patients. Another possibility is that both IL12 and INFγ production in WBCs are inhibited by eventual circulating serum factors.

     

BMP inhibition initiates neural induction via FGF signaling and Zic genes

Neural induction is the process that initiates nervous system development in vertebrates. Two distinct models have been put forward to describe this phenomenon in molecular terms. The default model states that ectoderm cells are fated to become neural in absence of instruction, and do so when bone morphogenetic protein (BMP) signals are abolished. A more recent view implicates a conserved role for FGF signaling that collaborates with BMP inhibition to allow neural fate specification. Using the Xenopus embryo, we obtained evidence that may unite the 2 views. We show that a dominant-negative R-Smad, Smad5-somitabun—unlike the other BMP inhibitors used previously—can trigger conversion of Xenopus epidermis into neural tissue in vivo. However, it does so only if FGF activity is uncompromised. We report that this activity may be encoded by FGF4, as its expression is activated upon BMP inhibition, and its knockdown suppresses endogenous, as well as ectopic, neural induction by Smad5-somitabun. Supporting the importance of FGF instructive activity, we report the isolation of 2 immediate early neural targets, zic3 and foxD5a. Conversely, we found that zic1 can be activated by BMP inhibition in the absence of translation. Finally, Zic1 and Zic3 are required together for definitive neural fate acquisition, both in ectopic and endogenous situations. We propose to merge the previous models into a unique one whereby neural induction is controlled by BMP inhibition, which activates directly, and, via FGF instructive activity, early neural regulators such as Zic genes.     

Expression of immediate-early genes reveals functional compartments within ocular dominance columns after brief monocular inactivation

Visual inputs from the 2 eyes in most primates activate alternating bands of cortex in layer 4C of primary visual cortex, thereby forming the well-studied ocular dominance columns (ODCs). In addition, the enzymatic reactivity of cytochrome oxidase (CO) reveals “blob” structures within the supragranular layers of ODCs. Here, we present evidence for compartments within ODCs that have not been clearly defined previously. These compartments are revealed by the activity-dependent mRNA expression of immediate-early genes (IEGs), zif268 and c-fos, after brief periods of monocular inactivation (MI). After a 1–3-h period of MI produced by an injection of tetrodotoxin, IEGs were expressed in a patchy pattern that included infragranular layers, as well as supragranular layers, where they corresponded to the CO blobs. In addition, the expressions of IEGs in layer 4C were especially high in narrow zones along boundaries of ODCs, referred to here as the “border strips” of the ODCs. After longer periods of MI (>5 h), the border strips were no longer apparent. When either eyelid was sutured, changes in IEG expression were not evident in layer 4C; however, the patchy pattern of the expression in the infragranular and supragranular layers remained. These changes of IEG expression after MI indicate that cortical circuits involving the CO blobs of the supragranular layers include aligned groups of neurons in the infragranular layers and that the border strip neurons of layer 4C are highly active for a 3-h period after MI.     

Somatic action potentials are sufficient for late-phase LTP-related cell signaling

A question of critical importance confronting neuroscientists today is how biochemical signals initiated at a synapse are conveyed to the nucleus. This problem is particularly relevant to the generation of the late phases of long-term potentiation (LTP). Here we provide evidence that some signaling pathways previously associated with late-LTP can be activated in hippocampal CA1 neurons without synaptic activity; somatic action potentials, induced by backfiring the cells, were found to be sufficient for phosphorylation of extracellular signal-regulated kinase-1/2 and cAMP response element-binding protein, as well as for induction of zif268. Furthermore, such antidromic stimulation was adequate to rescue "tagged" synapses (early-LTP) from decay. These results show that a synapse-to-nucleus signal is not necessary for late-phase LTP-associated signaling cascades in the regulation of gene expression.     

Exploring the neural correlates of self-related names in healthy subjects

Objectives:This study aimed to clarify the neural correlates and underlying mechanisms of the subject''s own name (SON) and the unique name derived from the SON (SDN).Methods:A name that was most familiar to the subject (SFN) was added as a self-related reference. We used 4 auditory stimuli—pure tone (1000 Hz), SON, SDN, and SFN—to evaluate the corresponding activated brain areas in 19 healthy subjects by using functional magnetic resonance imaging.Results:Our results demonstrated that pure tone activated the fewest brain regions. Although SFN was a very strong self-related stimulus, it failed to activate many midline structures. The brain regions activated by SON and SDN were very similar. SFN as a self-related stimulus was less self-related compared with SDN. What''s more, the additionally activated fusiform gyrus and parahippocampal gyrus of SDN might revealed its processing path.Conclusions:SDN, which has created by us, is a new and self-related stimulus similar to SON. They might provide a useful reference for consciousness assessment with SON and SDN.     

Bovine immunoglobulin concentrate-Clostridium difficile retains C difficile toxin neutralising activity after passage through the human stomach and small intestine

Background—Bovine immunoglobulinconcentrate (BIC)-Clostridium difficile isprepared from the colostrum of cows immunised against C difficile toxins and contains highconcentrations of neutralising IgG antitoxin.
Aims—To determine the proportion ofBIC-C difficile which survives passagethrough the human stomach and small intestine.
Methods—Six volunteers with an endileostomy took 5 g of BIC-C difficilecontaining 2.1 g of bovine IgG on four occasions: alone, with anantacid, during treatment with omeprazole, and within enteric coated capsules.
Results—WhenBIC-C difficile was taken alone, a mean (SEM) of 1033 (232) mg of bovine IgG was recovered in the ileal fluidrepresenting 49% of the total ingested dose. Bovine IgG recovery wasnot significantly increased by antacid (636 (129) mg) or omeprazole(1052 (268) mg). The enteric capsules frequently remained intact oronly partially opened in the ileal effluent and free bovine IgG levelswere low in this treatment group (89(101) mg). Bovine IgG recovery washigher in volunteers with shorter (less than two hours) mouth to ileumtransit times (68% versus 36%, p<0.05). Specific bovine IgG againstC difficile toxin A was detected in ilealfluid following oral BIC. Toxin neutralising activity was also presentand correlated closely with bovine IgG levels(r=0.95, p<0.001).
Conclusion—BIC-Cdifficile resists digestion in the human upper gastrointestinaltract and specific anti-C difficile toxin Abinding and neutralising activity was retained. Passive oral immunotherapy with anti-C difficile BIC maybe a useful non-antibiotic approach to the prevention and treatment ofC difficile antibiotic associated diarrhoeaand colitis.

Keywords:pseudomembranous colitis; toxin; diarrhoea; IgG; immunotherapy; antibiotic; Clostridiumdifficile

     

Characterisation of follicular dendritic cells in labial salivary glands of patients with primary Sjogren syndrome: comparison with tonsillar lymphoid follicles

OBJECTIVE—To localise and characterise follicular dendritic cells (FDC) present in autoimmune lesions of primary Sjogren syndrome.
METHODS—Cryostat sections of labial salivary glands from 15 patients with primary Sjogren syndrome were examined by an indirect immunoperoxidase technique and monoclonal antibodies to a panel of dendritic cell markers. Tonsils from two controls were also examined for the same markers.
RESULTS—FDC were localised in the centre of 75% of lymphoid focal structures in labial salivary gland biopsies. FDC in labial salivary glands of patients with primary Sjogren syndrome expressed CD35, CD11c, and CD106 (VCAM-1) in a pattern similar to FDC in tonsils, but they did not express either CD14 or CD11b. This indicates that they may not be of myeloid origin, while FDC in tonsillar lymphoid follicles strongly expressed both CD14 and CD11b. FDC in labial salivary glands of patients also lacked VLA-2α and VLA-3α, which were expressed by FDC in tonsils.
CONCLUSIONS—The characteristic phenotype and origin of these cells may be of importance in the immune responses involved in Sjogren syndrome and the retention of infiltrating lymphocytes in the glands.

     

Inhibition of phenolsulphotransferase by salicylic acid: a possible mechanism by which aspirin may reduce carcinogenesis

Background—Recent epidemiological evidence hasshown that chronic use of aspirin decreases susceptibility to bowelcancer. Animal studies have shown that sulphotransferase inhibitorscoadministered with sulphation activated carcinogens dramaticallyreduce the incidence of cancer.
Aims—To investigate the effect of the mainaspirin breakdown product, salicylic acid, on the P and M isoforms ofphenolsulphotransferase from human platelets and colonic mucosa.
Methods—Platelets were obtained from healthyblood donors and isolated within 24 hours after donation. Samples ofcolonic mucosa were obtained at resection for non-malignant disease.Phenolsulphotransferase activity was measured in cellular homogenatesusing a standard radiolabelling assay.
Results—Salicylic acid consistently andselectively inhibited the P form of phenolsulphotransferase atsubtherapeutic concentrations in both tissue samples. A 50% inhibitionof sulphation by the P phenolsulphotransferase occurred at salicylicacid concentrations of about 40 and 130 µM in platelets and bowelmucosa respectively. M phenolsulphotransferase was virtually unaffectedby salicylic acid up to a concentration of 1.5 mM (the therapeuticplasma concentration for salicylates when treating rheumatoid arthritisis about 1-2 mM).
Conclusion—The action of salicylic acid on Pphenolsulphotransferase, by preventing the excessive activation ofcarcinogens, is a possible additional pathway by which aspirin canreduce cancer risk.

Keywords:colorectal cancer; non-steroidal anti-inflammatorydrugs; phenolsulphotransferases

     

Dominant mutations in the tyrosyl-tRNA synthetase gene recapitulate in Drosophila features of human Charcot–Marie–Tooth neuropathy

Dominant-intermediate Charcot–Marie–Tooth neuropathy (DI-CMT) is characterized by axonal degeneration and demyelination of peripheral motor and sensory neurons. Three dominant mutations in the YARS gene, encoding tyrosyl-tRNA synthetase (TyrRS), have so far been associated with DI-CMT type C. The molecular mechanisms through which mutations in YARS lead to peripheral neuropathy are currently unknown, and animal models for DI-CMTC are not yet available. Here, we report the generation of a Drosophila model of DI-CMTC: expression of the 3 mutant—but not wild type—TyrRS in Drosophila recapitulates several hallmarks of the human disease, including a progressive deficit in motor performance, electrophysiological evidence of neuronal dysfunction and morphological signs of axonal degeneration. Not only ubiquitous, but also neuron-specific expression of mutant TyrRS, induces these phenotypes, indicating that the mutant enzyme has cell-autonomous effects in neurons. Furthermore, biochemical and genetic complementation experiments revealed that loss of enzymatic activity is not a common feature of DI-CMTC-associated mutations. Thus, the DI-CMTC phenotype is not due to haploinsufficiency of aminoacylation activity, but most likely to a gain-of-function alteration of the mutant TyrRS or interference with an unknown function of the WT protein. Our results also suggest that the molecular pathways leading to mutant TyrRS-associated neurodegeneration are conserved from flies to humans.     

Calcium-activated nonspecific cation current and synaptic depression promote network-dependent burst oscillations

Central pattern generators (CPGs) produce neural-motor rhythms that often depend on specialized cellular or synaptic properties such as pacemaker neurons or alternating phases of synaptic inhibition. Motivated by experimental evidence suggesting that activity in the mammalian respiratory CPG, the preBötzinger complex, does not require either of these components, we present and analyze a mathematical model demonstrating an unconventional mechanism of rhythm generation in which glutamatergic synapses and the short-term depression of excitatory transmission play key rhythmogenic roles. Recurrent synaptic excitation triggers postsynaptic Ca²⁺-activated nonspecific cation current (I_CAN) to initiate a network-wide burst. Robust depolarization due to I_CAN also causes voltage-dependent spike inactivation, which diminishes recurrent excitation and thus attenuates postsynaptic Ca²⁺ accumulation. Consequently, activity-dependent outward currents—produced by Na/K ATPase pumps or other ionic mechanisms—can terminate the burst and cause a transient quiescent state in the network. The recovery of sporadic spiking activity rekindles excitatory interactions and initiates a new cycle. Because synaptic inputs gate postsynaptic burst-generating conductances, this rhythm-generating mechanism represents a new paradigm that can be dubbed a ‘group pacemaker’ in which the basic rhythmogenic unit encompasses a fully interdependent ensemble of synaptic and intrinsic components. This conceptual framework should be considered as an alternative to traditional models when analyzing CPGs for which mechanistic details have not yet been elucidated.     

Improved clinical tolerance to chronic lactose ingestion in subjects with lactose intolerance: a placebo effect?

Background—Uncontrolled studies of lactoseintolerant subjects have shown that symptom severity decreases afterchronic lactose consumption. Adaptation of the colonic flora mightexplain this improvement.
Aims—To compare the effects of regularadministration of either lactose or sucrose on clinical tolerance andbacterial adaptation to lactose.
Methods—Forty six lactose intolerant subjectsunderwent two 50 g lactose challenges on days 1 and 15. Between thesedays they were given 34 g of lactose or sucrose per day, in a doubleblind protocol. Stool samples were obtained on days 0 and 14, tomeasure faecal β-galactosidase and pH. Symptoms, breathH₂ excretion, faecal weight and electrolytes, and orofaecaltransit time were assessed.
Results—Except for faecal weight, symptomswere significantly milder during the second challenge in both groups,and covariance analysis showed no statistical difference between them.In the lactose group, but not in the sucrose group, faecalβ-galactosidase activity increased, pH dropped, and breathH₂ excretion decreased.
Conclusion—Bacterial adaptation occurredwhen lactose intolerant subjects ingested lactose for 13 days, and allsymptoms except diarrhoea regressed. Clinical improvement was alsoobserved in the control group which displayed no signs of metabolicadaptation. This suggests that improved clinical tolerance may be justa placebo effect.

     

Facilitatory transmitters and cAMP can modulate accommodation as well as transmitter release in Aplysia sensory neurons: Evidence for parallel processing in a single cell

Presynaptic facilitation of transmission from sensory to motor neurons contributes significantly to behavioral sensitization of defensive withdrawal reflexes in Aplysia. Presynaptic facilitation is associated with a decrease in the serotonin-sensitive K⁺ conductance. This decrease broadens the presynaptic action potential. In addition, the procedures that cause facilitation—stimulation of the connective (the pathway from the tail and head), application of modulatory transmitters, or injection of cAMP—also increase the excitability of the sensory neurons as tested with intracellular depolarizing pulses injected into the cell body. The increased excitability is reflected in a decreased threshold for generating action potentials and a reduction in accommodation to prolonged constant current stimuli. By influencing the excitability of the peripheral processes of the sensory neurons, stimulation of the connectives or serotonin also produces a small enhancement of the response of the sensory neurons to a tactile stimulus applied to the siphon. The excitability changes appear to result, at least in part, from the same cellular mechanisms that lead to broadening of the action potential, a cAMP-mediated closure of K⁺ channels. Therefore, these findings indicate that the same class of mechanisms can, in principle, have a dual action and provide further evidence for parallel processing in the modulation of transmitter release from a single neuron.     

Experimental pain in the stomach: a model based on electrical stimulation guided by gastroscopy

Background—Abdominal pain is often variable inintensity and difficult to characterise due to its referred painpattern. Clinical pain is furthermore confounded by various emotionaland cognitive factors.
Aims—To develop and apply an experimental modelto induce localised gastric pain.
Subjects—Twelve healthy male volunteers.
Methods—Stimulating electrodes were mounted on abiopsy forceps and electric stimuli were delivered during gastroscopy.Single, five repeated, and continuous stimuli were given at fourlocations in the stomach. Pain detection thresholds and painintensities were assessed together with localisation of the referredpain area.
Results—Pain detection thresholds were higher inthe prepyloric region compared with those obtained at the lesser andgreater curvature. Increasing stimulus intensity resulted in augmented pain perception and repeated stimuli elicited pain at a lower stimulusintensity than single stimuli. Continuous stimuli evoked constant(33%), increasing (33%), or decreasing (33%) pain. The localisationof referred pain varied considerably in the subjects.
Conclusions—The model seems relevant to studybasic pain mechanisms elicited by localised stimuli in the stomach. Theexperimental data support the premise that a gastric focus shouldalways be suspected in patients referred with different kinds ofabdominal pain.

     

GPI-anchored carbonic anhydrase IV displays both intra- and extracellular activity in cRNA-injected oocytes and in mouse neurons

Soluble cytosolic carbonic anhydrases (CAs) are well known to participate in pH regulation of the cytoplasm of mammalian cells. Membrane-bound CA isoforms—such as isoforms IV, IX, XII, XIV, and XV—also catalyze the reversible conversion of carbon dioxide to protons and bicarbonate, but at the extracellular face of the cell membrane. When human CA isoform IV was heterologously expressed in Xenopus oocytes, we observed, by measuring H⁺ at the outer face of the cell membrane and in the cytosol with ion-selective microelectrodes, not only extracellular catalytic CA activity but also robust intracellular activity. CA IV expression in oocytes was confirmed by immunocytochemistry, and CA IV activity measured by mass spectrometry. Extra- and intracellular catalytic activity of CA IV could be pharmacologically dissected using benzolamide, the CA inhibitor, which is relatively slowly membrane-permeable. In acute cerebellar slices of mutant mice lacking CA IV, cytosolic H⁺ shifts of granule cells following CO₂ removal/addition were significantly slower than in wild-type mice. Our results suggest that membrane-associated CA IV contributes robust catalytic activity intracellularly, and that this activity participates in regulating H⁺ dynamics in the cytosol, both in injected oocytes and in mouse neurons.     

Major virulence factors, VacA and CagA, are commonly positive in Helicobacter pylori isolates in Japan

Background—VacA and CagA proteins have beenreported to be major virulence factors of Helicobacterpylori. However, antibodies against these proteins arefrequently found in the sera of Japanese patients regardless of theirgastroduodenal status.
Aim—To evaluate the expression of VacA and CagAproteins by H pylori strains isolated in Japan.
Methods—By using specific antibodies raisedagainst recombinant VacA and CagA proteins, the expression of VacA andCagA was evaluated in 68 H pylori strains isolated fromJapanese patients; a vacuolating assay and genotyping of thevacA gene were also used in the evaluation. The resultswere analysed in relation to the gastroduodenal diseases of the hosts.
Results—VacA and CagA proteins were expressed in59/68 (87%) and in 61/68 (90%) isolates respectively. The vacuolatingassay was positive in 57/68 (84%) isolates, indicating that mostimmunologically VacA positive strains produced active cytotoxin. Theprevalence of infection with strains expressing CagA and positive forvacuolating activity (Type I) was very high, 54/68 (79%), irrespectiveof the gastroduodenal status of the host.
Conclusion—Most H pylori isolates inJapan are positive for vacuolating cytotoxin and CagA, and thus thesevirulence factors cannot be used as markers to discern the risk ofdeveloping serious gastroduodenal pathologies in the hosts. However,the high prevalence of infection with strains positive for vacuolatingcytotoxin and CagA may contribute to the characteristics of Hpylori infection in Japan.

Keywords:VacA; Helicobacter pylori; CagA; ulcer; non-ulcer dyspepsia