Diffuse adherence, ST-I enterotoxin and CFA/IV colonization factor are encoded by the same plasmid in the Escherichia coli O29:H21 strain

Escherichia coli O29:H21 is a human enterotoxigenic serotype that produces heat-stable (ST-I) enterotoxin, adheres diffusely to HeLa cells, and presents colonization factor antigen IV (CFA/IV) composed of CS5CS6 surface antigens. In one strain studied the genes for diffuse adherence and CFA/IV (CS5CS6) production were found to be present in the same plasmid encoding ST-I. The virulence plasmid (Ent) presented two unrelated basic replicons homologous to repFIC and repW. Gene(s) encoding diffuse adherence did not share homology with the probe for F1845 fimbrial adhesin which is responsible for this phenotype in other E. coli strains. Ent plasmids containing genes for diffuse adherence have not been described previously.     

Dorsal spinocerebellar tract neuronal activity in the intact chronic cat

The ability to electrophysiologically identify the axonal projections of lumbar neurons recorded in chronic unanesthetized intact awake animals is a formidable but essential requirement toward understanding ascending sensory transmission under naturally occurring conditions. Chronic immobilization procedures previously introduced by Morales et al. (1981) for intracellular studies of motoneurons are modified and then integrated with procedures for antidromic cellular identification and extracellular recording of upper (or lower) dorsal lumbar spinocerebellar tract (DSCT) neuronal activity, in conjunction with behavioral state recording and drug microiontophoresis. These implant procedures provide up to 6 months of stable recording conditions and, when combined with other techniques, allow individual DSCT neurons to be monitored over multiple cycles of sleep and wakefulness, following the induction into and recovery from barbiturate anesthesia and/or during the juxtacellular microiontophoretic ejection of inhibitory or excitatory amino acid neurotransmitters. The combination of such techniques allows a comprehensive examination of synaptic transmission through the DSCT and other lumbar sensory pathways in the intact normally respiring cat and its modulation during the general anesthetic state. These techniques permit investigations of the supraspinal controls impinging on lumbar sensory tract neurons during wakefulness and other behavioral states such as active sleep.     

Different effects of salmeterol, formoterol and salbutamol on cholinergic responses in the ferret trachea

1. In the present study, the inhibitory effects of the selective beta 2-adrenoceptor agonists, salmeterol, formoterol and salbutamol, have been investigated on contractions of ferret trachea induced both by endogenous and exogenous acetylcholine. The aim of the study was to evaluate quantitative and/or qualitative differences in response which may indicate both pre- and post-junctional sites of action. The non-selective beta-antagonist, sotalol, was used to estimate beta-adrenoceptor involvement. 2. Isometric tension was measured in ferret isolated tracheal strips. The inhibitory effects of the drugs were studied on tonic contractions induced by pre-junctional activation with electrical field stimulation (EFS) (2 Hz, 700 mA) or post-junctional activation with exogenous acetylcholine (ACh) (0.5 microM, about EC80), giving a similar degree of smooth muscle response. 3. Concentration-response experiments were performed with formoterol (0.3 nM-0.3 microM) and salmeterol and salbutamol (10 nM-10 microM). The experiments ended with the addition of sotalol (10 microM). 4. All three beta-agonists inhibited the contractions in a concentration-dependent manner. Salbutamol, formoterol and salmeterol inhibited the EFS-induced contractions by 66(8)%, 105(5)% and 103(8)% (mean(s.e. mean)) respectively. ACh-induced contractions were inhibited by 37(6)%, 72(11)% and 33(8)%. Theophylline (10 nM-3 mM) inhibited the contractions to the same degree. 5. beta-Adrenoceptor blockade by sotalol significantly antagonized the inhibitory effects of salbutamol and formoterol on both EFS- and ACh-induced contractions. The effect of salmeterol on ACh-induced contraction was also significantly antagonized, whereas the inhibition of EFS-induced contraction was virtually unaffected. 6. In conclusion, salbutamol, salmeterol and formoterol produced greater inhibitory effects in preparations contracted by EFS than in preparations contracted by exogenously-added ACh. In the case of formoterol and salbutamol, the effects on both levels are most probably due to beta-adrenoceptor stimulation, whereas for salmeterol the dominant pre-junctional effect is probably not mediated via beta-adrenoceptors. This non-beta-mediated effect could represent an additional relaxant mechanism for salmeterol.     

Relationships between gastric emptying, intragastric meal distribution and blood glucose concentrations in diabetes mellitus

The aim of this study was to evaluate the prevalence of disordered intragastric meal distribution and the relationships between gastric emptying, intragastric distribution, glycemic control and gastrointestinal symptoms in diabetes mellitus. METHODS: Eighty-six patients with diabetes mellitus had measurements of gastric emptying and intragastric distribution of a radioisotopically labeled solid/liquid meal (100 g beef and 150 ml 10% dextrose), glycemic control (plasma glucose concentrations), upper gastrointestinal symptoms (questionnaire) and autonomic nerve function (cardiovascular reflexes). Results were compared to those obtained in 20 normal volunteers. RESULTS: Solid and liquid gastric emptying were delayed in the diabetic patients and correlated weakly. Intragastric meal distribution was also often abnormal, with increased retention of both solid and liquid in the proximal stomach and increased retention of solid but not liquid in the distal stomach. In all patients with increased retention of solid in the proximal stomach, emptying from the total stomach was delayed. Gastric emptying of liquid was slower in those subjects who had a mean plasma glucose > 15 mmol/liter during the gastric emptying measurement, when compared to the remainder of the group. CONCLUSION: In patients with diabetes mellitus, there is poor relationship between solid and liquid gastric emptying and intragastric meal distribution is frequently abnormal. Interpretation of the results of gastric emptying measurements should consider meal composition and plasma glucose concentrations.