Biological activity & interaction of Vibrio cholerae bacteriophages in rabbit ileal loop.

A set of ten V. cholerae EITor phages is in routine use for phage typing of V. cholerae O1 biotype EITor strains.

Circle systems with a coaxial inspiratory limb. Investigation with a lung model.

A laboratory study of a new circle system is presented. The inspiratory limb encloses a coaxial tube, delivering fresh gas close to the patient, immediately upstream of the inspiratory one-way valve. The system is more efficient than the non-coaxial system and allows the expiratory valve to be situated conveniently at the canister end of the expiratory limb.

Measuring rebreathing in spontaneous ventilation. A new lung model.

The performance of breathing systems is tested by means of physical lung models. We describe a new lung model, allowing direct measurement of the dead space/tidal volume ratios produced by any breathing system at different fresh gas flows. The model allows a range of different patterns of spontaneous respiration to be studied.

Uptake of desflurane during anaesthesia.

The amount of desflurane required to maintain an end-expired concentration of 8% was measured in 30 ASA 1 and 2 patients undergoing elective spinal surgery. The anaesthetic was administered using a computer-controlled closed circle system. After an initial period during which the expired concentration of desflurane was stabilised (4 min) the rate of uptake showed a bi-exponential decline.

Role of outer membrane proteins on the adherence of Vibrio parahaemolyticus to rabbit intestinal epithelial cell in vitro.

Antiserum against outer membrane preparation of a Kanagawa phenomenon-positive strain of Vibrio parahaemolyticus were raised in rabbits and absorbed with their lipopolysaccharide. The anti-outer membrane protein serum and its Fab (IgG) fragment inhibited the adherence of Kanagawa-positive strains to rabbit intestinal epithelial cells in vitro. Preincubation of rabbit intestinal epithelial cells with outer membrane preparation also inhibited the adherence of these bacteria.

Biodistribution and radioimmunopharmacokinetics of 131I-Ama monoclonal antibody in atherosclerotic rabbits.

Monoclonal antibodies have been raised against Ama isolated from human and experimental atherosclerotic plaque. 131I-Ama-MoAb in the whole antibody form was injected into normal NZW rabbits and Watanabe hyperlipidemic rabbits. Biodistribution studies showed that atheromatous aortas had a significantly higher (5-7X) uptake of 131I-Ama-MoAb than that of normal aortas.

The estimation of inspired isoflurane concentration in a low-flow system.

We have examined the predictability of inspired isoflurane concentration during low-flow anaesthesia using a to-and-fro breathing system. Twenty one adult patients requiring mechanical ventilation of the lungs during surgery took part in this study. Using a fresh gas flow of 2 l.

The uptake of enflurane during anaesthesia.

The uptake of enflurane at a constant end-expired concentration of 2% in oxygen was studied in 38 patients, ASA 1 or 2, undergoing elective orthopaedic procedures. The anaesthetic was administered using a computer-controlled closed circle system. Following an initial 4 min period during which the expired concentration of enflurane was established, the rate of uptake of enflurane showed a triexponential decline.

Ventilation techniques to minimize circulatory depression in rabbits with surfactant deficient lungs.

Changes in aortic blood flow were measured in rabbits with both normal and surfactant depleted lungs in order to elucidate the effect of different modes of ventilation on the circulation while optimizing arterial oxygenation (PaO2). Conventional mechanical ventilation (CMV), reversed inspiratory to expiratory ratio of CMV (IRV), high frequency positive pressure ventilation (HFV), and high frequency oscillation (HFO) were used. Normocapnia was maintained throughout during different modes of ventilation.

Antigenicity and antigenic cross-reactivity of outer membrane proteins of Vibrio parahaemolyticus.

Antigenicity of outer membrane proteins was studied and compared between Kanagawa positive (clinical) and negative (environmental) strains of Vibrio parahaemolyticus. Murine antibodies recognized a wide range of outer membrane proteins of Kanagawa negative strains as antigens with molecular masses ranging between 102 kDa to 14 kDa. However, only a few of the total outer membrane proteins of clinical isolates were antigenic and comprised a 55kDa protein as the major antigen.

Comparison of clonidine with fentanyl on phrenic nerve activity and their interaction in anaesthetized rabbits.

We have compared the effects of clonidine and fentanyl on phrenic nerve activity in anaesthetized rabbits during artificial ventilation. Both drugs caused dose-dependent inhibition of phrenic nerve activity and complete abolition in all experiments. The calculated ED50 values were 3.

Clonidine has comparable effects on spontaneous sympathetic activity and afferent A delta and C-fiber-mediated somatosympathetic reflexes in dogs.

Background: Clonidine, an alpha 2-adrenergic agonist, has been studied as an adjunct or alternative to spinal opioids in the management of moderate to severe pain. This study examined the relative effects of clonidine on efferent spontaneous sympathetic activity and afferent A delta and C fiber-mediated somatosympathetic responses.

Methods: Spontaneous and evoked sympathetic activity in renal sympathetic nerves, mediated by A delta and C fibers by means of supramaximal electrical stimulation of the radial and tibial nerves, were observed in anesthetized dogs.

The Ohmeda Rascal II. A new gas analyser for anaesthetic use.

The Ohmeda Rascal II is a multigas analyser and pulse oximeter for dedicated anaesthetic.use. It uses the Raman scattering of laser light to identify and quantify oxygen, nitrogen, carbon dioxide, nitrous oxide and three volatile anaesthetic agents.

Cardiorespiratory effects of conventional and high frequency ventilation in rabbits with bilateral pneumothoraces and surfactant depleted lungs.

We compared high frequency ventilation (HFV) to conventional mechanical ventilation (CMV) under normoxic and normocapnic condition in surfactant depleted rabbits with bilateral pneumothoraces. We hypothesized that lower airway pressures would be required with HFV under these conditions. We applied CMV and HFV in 8 anaesthetized rabbits with a prototype ventilator at frequencies of 30, 100, 200, and 300 cycles/min.

Effect of ICI197067, a kappa-opioid receptor agonist, spinally on A delta and C reflexes and intracerebrally on respiration.

Intrathecal (i.t.) injection of a kappa-opioid receptor agonist, ICI197067, caused a similar dose dependent depression of A delta and C fibre mediated nociceptive reflexes in renal sympathetic nerves due to supramaximal electrical stimulation of tibial nerves in anaesthetized dogs.

Lack of a ceiling effect for intrathecal buprenorphine on C fibre mediated somatosympathetic reflexes.

We observed that buprenorphine 20 micrograms kg-1 i.v. in dogs caused an initial significant reduction in both A delta and C fibre mediated somatosympathetic reflexes evoked by tibial and radial nerve stimulation, to approximately 75% and 70% of control values.

Specific enhancement by fentanyl of the effects of intrathecal bupivacaine on nociceptive afferent but not on sympathetic efferent pathways in dogs.

Background: Bupivacaine alone, or in combination with opioids, has been shown to provide adequate pain relief without motor paralysis. This study examined the effects of bupivacaine administered intrathecally on sympathetic efferent and A delta- and C-fiber-mediated afferent pathways in dogs and the interactions with intrathecal fentanyl.

Methods: Spontaneous activity in renal sympathetic nerves was observed, as were reflex somatosympathetic responses mediated by A delta and C fibers evoked by supramaximal electrical stimulation of the tibial and radial nerve.

The uptake of isoflurane during anaesthesia.

The uptake of isoflurane at a constant end-expired concentration of 1.5% in oxygen was studied in 15 women, ASA 1 or 2, undergoing elective total abdominal hysterectomy. The anaesthetic was administered by a simple computer-controlled to-and-fro closed system.

A computer-controlled closed anaesthetic breathing system.

We describe the design and working of a computer-controlled, closed anaesthetic breathing system which rapidly achieves and maintains a prescribed end-tidal concentration of isoflurane in oxygen. The system is simple to set up and not expensive; the only nonstandard component is a modified glass syringe. We have demonstrated that gas analysers may contribute as much as the patient to the accumulation of nitrogen within the breathing system.

An evaluation of anaesthetic loss from a closed breathing system.

We present the results of a laboratory study of the loss of isoflurane from a to-and-fro system, ventilated with oxygen, using a standard ventilator connected to the system via a long corrugated tube (the trunk) in place of the reservoir bag. No conventional fresh gas supply is used and isoflurane is injected as a liquid directly into the soda lime canister. The loss of isoflurane from the system due to mixing in the trunk was generally less than that lost by absorption into rubber and plastic system components.

Synergism between the antinociceptive effects of intrathecal midazolam and fentanyl on both A delta and C somatosympathetic reflexes.

The interaction between the antinociceptive effects of fentanyl and midazolam, administered intrathecally (i.t.), was examined in dogs.

Evaluation of the efficacy of different antibiotics in inhibiting colonisation of Vibrio cholerae O1 in the rabbit intestine.

The efficacy of ciprofloxacin, norfloxacin and tetracycline in prevention of colonisation of V. cholerae O1 in the rabbit intestine were tested. V.

Differential effects of alfentanil, fentanyl, pethidine and lignocaine administered intrathecally on nociceptive responses evoked by low and high frequency stimulation of somatic nerves.

We have studied in anaesthetized dogs the effects of alfentanil, fentanyl, pethidine and lignocaine administered intrathecally on nociceptive responses evoked by low and high frequency supramaximal electrical stimulation of the tibial and radial nerves. Doses were selected to abolish both A delta and C fibre somatosympathetic reflexes to single stimuli. Pethidine and lignocaine eliminated reflex pressor and heart rate responses to repeated single stimuli and almost completely abolished responses to train stimulation.