Restorative proctocolectomy with a three-loop ileal reservoir for ulcerative colitis and familial adenomatous polyposis. Clinical results in 66 patients followed for up to 6 years

The results of restorative proctocolectomy with a three-loop ileal reservoir were reviewed. Of 66 patients treated between 1976 and 1982, 52 had ulcerative colitis and 14 had familial adenomatous polyposis. The temporary ileostomy was closed between 2 and 78 months previously in 63 cases. Of these, three patients had had the reservoir removed and two were lost to follow-up. One other patient was subsequently found to have Crohn's disease. Function was assessed in 55 patients who had undergone closure of the ileostomy more than 8 weeks previously. Mean frequency of defecation was 3.7 per 24 hours (range 1-9.5) and 11 patients (20%) were taking antidiarrheal medication. Spontaneous defecation occurred in 22 patients (40%) while 29 (52.7%) had to use a catheter passed per anum. Four patients defecated spontaneously but sometimes used a catheter. Continence was normal in 36 (65.4%) and minor leakage once every 2 to 3 days occurred at night in 16 (29.1%). Three patients (5.4%) had some soiling during day and night. Troublesome perianal soreness (five patients, 9.1%) necessitated a defunctioning ileostomy in one. Fifty-four of the 55 patients assessed preferred their quality of life to that with an ileostomy.

Structural and functional analysis of synaptic transmission between identified leech neurones in culture

The fine structure and physiological properties of chemical synapses that develop between identified leech neurones in culture have been studied by electron microscopy and by quantal analysis. Earlier work has shown that the transmitter liberated by isolated Retzius cells, serotonin, evokes chloride-dependent inhibitory post-synaptic potentials (i.p.s.p.s) in P sensory cells, and also in Retzius cells. When pairs of Retzius cells or Retzius and P sensory cells were placed in close apposition in culture for a few days, their somata extended numerous fine processes which came into contact and interdigitated. In the region of interdigitation, only narrow spaces, approximately 20-25 nm wide separated the membranes. The appearance of the cytoplasm of the two neurones was distinctive: in particular, Retzius cells contained agranular vesicles, as well as abundant dense core vesicles which were not as prevalent in P cells. Structures resembling synapses developed by 4 days, with characteristic vesicles clustered in terminals of the Retzius cell apposed to the post-synaptic membrane. In the presence of raised Mg or lowered Ca in the culture medium, the i.p.s.p. in the P cell evoked by an impulse in the Retzius cell became diminished in amplitude. The time-to-peak and half-time of decay were unchanged. Under these conditions, with repeated stimulation, quantal fluctuations of these post-synaptic potentials and failures were observed. In addition, there occurred spontaneous events which resembled miniature synaptic potentials and had amplitudes and time courses similar to those of the unitary events evoked by presynaptic impulses. The amplitudes of evoked synaptic potentials in raised Mg were distributed in accord with the Poisson equation. The agreement was good when either the spontaneous miniature potentials or the failures of evoked release were used to calculate m, the mean number of quanta per trial. With larger values of m the results were distributed as predicted by the binomial equation. These morphological and electrophysiological experiments together indicate that the inhibitory potentials observed in P cells result from quantal units of transmitter released by presynaptic terminals of the Retzius cell which are in close apposition to the post-synaptic membrane.

Disseminated infection with mycobacterium chelonei in a haemodialysis patient

M. chelonei ssp. chelonei was isolated over a period of 5 months from abscesses on various sites of hands and feet of a patient on maintenance dialysis. The organism was resistant in vitro to a greater number of antimicrobials and treatment in turn with gentamicin, vancomycin, erythromycin, doxycycline and co-trimoxazole had to be supplemented by surgical drainage of abscesses. Examination of the dialysis circuit revealed repeatedly the presence of M. chelonei and M. fortuitum in the water softener resin and other sites. The significance of this finding is discussed.

Supersonically expanding reacting flows : the chemiluminescent Sn/N2O reaction

A supersonic flow reactor comprising a shock tube and convergent-divergent expansion nozzle has been developed and used to study the chemiluminescent reaction between tin atoms and nitrous oxide. The reaction has been found to excite the a-X, b-X and A-X transitions of SnO and rate constants for formation of the three excited states have been found to have the same activation energy, 25�5 kJ mol-1. Estimates of branching ratios have been made on the basis of experimental measurement and kinetic modelling and an assessment of the Sn/N2O reaction as a possible electronic chemical laser is made.

The 4-methylumbelliferone sulphate sulphatases of human tears

The properties of human tear 4-methylumbelliferone sulphate sulphatase (EC 3.1.6.1) have been investigated. More than 80% of the enzyme activity behaved as the acidic A isoenzyme on isoelectric focusing and DEAE-cellulose ion exchange chromatography. The distribution of enzyme activity in a normal population has been investigated. The least interindividual variation was seen when enzyme activities were calculated as units per mg tears. The alpha-galactosidase, beta-N-acetylglucosaminidase and sulphatase enzyme activities in human tears varied independently of each other. The use of tear sulphatases for the detection of metachromatic leukodystrophy (McKusick 24980) is discussed.

Identified neurones isolated from leech CNS make selective connections in culture

Neurones cultured in vitro offer distinct advantages for studying how processes grow towards their targets and form synaptic connections. In contrast to the complex events occurring during the development of the nervous system, synapse formation in culture can be analysed in a few neurones at a time and under controlled conditions. We have now dissected out and cultured single identified neurones from the central nervous system (CNS) of the adult leech. Various types of sensory cells, motor cells, and interneurones can be identified in leech ganglia--each with a stereotyped set of properties, including: (1) the electrical characteristics of its membrane, (2) the arborisation of its branches and the morphology of its terminals and (3) the pattern of connections it makes with other identified neurones, skin or muscle. Thus, cultured cells can be compared in detail with their counterparts in situ. We have found that isolated cells survive for several weeks, maintain their membrane properties, sprout and form selective connections.

Destruction of a single cell in the central nervous system of the leech as a means of analysing its connexions and functional role

A method has been devised for killing an individual neurone in the C.N.S. of the leech by injecting it with Pronase. The technique has been used to examine the role of individual sensory and motor cells involved in producing reflex movements.1. After a neurone was injected with Pronase, either in an intact animal or an isolated ganglion, its cell body lost its resting and action potentials. Some hours later the injected cell's axons in the periphery failed to conduct impulses. In the intact animal the cell body could no longer be discerned after a few weeks.2. To test for destruction of processes within the neuropile, cells were injected first with the enzyme horseradish peroxidase (HRP) and then several hours later with Pronase. Absence of the characteristic HRP reaction product indicated that Pronase had spread throughout the arborization of the cell.3. Injection of Pronase into one cell did not produce overt electrophysiological or anatomical changes in other cells in the ganglion including neurones that were originally electrically coupled to the killed cell.4. Evidence that an individual cell was the only motoneurone supplying particular muscles was provided by destruction of that cell in otherwise intact animals, which resulted in a characteristic motor deficit in the area supplied by the killed cell. Over a period of months, functional recovery of the affected muscles occurred by way of homologous cells in adjacent ganglia.5. A further application of the technique was to trace the connexion that a particular sensory neurone makes onto two motoneurones that are electrically coupled. Normally, the sensory neurone gives rise to excitatory potentials in both post-synaptic cells. Synaptic potentials could still be recorded in one motor cell after the other had been destroyed by Pronase, indicating that synapses were made directly onto both of the motoneurones.

Quantal analysis of transmitter release at an inhibitory synapse in the central nervous system of the leech

The quantal nature of transmitter release has been analysed at central inhibitory synapses in the leech nervous system between an interneurone (HN) and a motoneurone (HE) that regulate the heartbeat. 1. Ganglia were bathed in leech Ringer fluid containing 20 mM-Mg and 1.8 mM-Ca and the membrane of the presynaptic HN interneurone was hyperpolarized by current injection. Under these conditions successive inhibitory potentials in the HE motoneurone, evoked by impulses in the HN interneurone, showed striking fluctuations in amplitude. 2. Assuming a Poisson distribution of the i.p.s.p.s and estimating the number of failures from the amplitude histograms of the observed responses, the mean size of the quantal unit was estimated as 0.25 +/- 0.015 mV (S.E. of mean, n = 26). When m, the mean number of quanta released per trial, was varied by changing the membrane potential of the presynaptic HN cell (Nicholls & Wallace, 1978), the experimentally observed amplitude distributions could be predicted by the Poisson theory. 3. An independent estimate of the unit size was obtained by noise analysis. A long subthreshold depolarizing pulse applied to the presynaptic HN interneurone evoked a sustained hyperpolarization of the HE motoneurone, apparently caused by an increase in the rate of on-going release of quanta by the HN cell terminals. From the mean change in membrane potential and the increase in variance, the size of the unit was calculated as 0.21 +/- 0.039 mV (S.E. of mean, n = 11). For ten pairs of cells an estimate of unit amplitude was made both from the Poisson analysis and the analysis of variance, again with good agreement. For these cells the estimated unit sizes were 0.24 +/- 0.023 mV (S.E. of mean, n = 10) from the failures and 0.21 +/- 0.043 m V (S.E. of mean, n = 10) from the noise. 4. A similar analysis was made of the inhibitory synaptic potentials evoked in one HN interneurone by stimulation of its contralateral homologue. Transmission again appeared to be qualtal; the mean unit amplitude from Poisson analysis was 0.31 +/- 0.022 mV (S.E. of mean, n = 19) and from the noise 0.29 +/- 0.027 mV (S.E. of mean, n = 3). 5. We conclude that transmitter is released from the terminals of the HN interneurone in quantal units that evoke miniature i.p.s.p.s of about 0.25 mV in the post-synaptic cells. Furthermore, modulation of transmission proudced by variation in the presynaptic resting potential and during presynaptic inhibition results from changes in the mean number of quanta released by each impulse.

Modulation of transmission at an inhibitory synapse in the central nervous system of the leech

The synaptic interactions among a group of cells in the leech C.N.S. that regulate the animal's heartbeat exhibit several remarkable features (Thompson & Stent, 1976 a, b, c). We have examined in detail the properties of the inhibitory synapse between two of these cells, the heart interneurone (HN cell) and the heart excitor motoneurone (HE cell). 1. Impulses in the presynaptic HN cell gave rise to monosynaptic i.p.s.p.s in the HE cell that were blocked by high concentrations of Mg and were reversed when the membrane potential of the post-synaptic motoneurone was hyperpolarized beyond--75 m V or when Cl was injected into the cell body. These i.p.s.p.s were chemically mediated, and involved an increase in chloride conductance. 2. In contrast to chemical synapses between sensory and motor cells in the leech C.N.S., little facilitation or depression of transmission occurred when the HN cell was stimulated at frequencies of 0.1--50 Hz. 3. Steady subthreshold depolarization of the presynaptic HN interneurone evoked a maintained hyperpolarization of the post-synaptic HE cell, indicating that currents injected into the HN cell body could spread to the terminals and cause continuous release of transmitter. 4. The size of the i.p.s.p. evoked in the HE motoneurone by an action potential in the HN interneurone varied with the resting membrane potential of the presynaptic cell. An impulse superimposed on a prolonged, subthreshold, depolarizing pulse produced a larger i.p.s.p.; conversely, prolonged hyperpolarization of the HN interneurone reduced the i.p.s.p. amplitude recorded in the HE cell. This effect was most obvious when the natural, rhythmical bursts of activity in the HN interneurone were interrupted by bathing the preparation in leech Ringer fluid containing elevated concentrations of Mg. Under these conditions a 10 mV depolarization of the HN cell increased the size of the i.p.s.p. in the HE cell approximately sixfold. Significant changes in i.p.s.p. amplitude occurred without any noticeable change in the amplitude and duration of the presynaptic action potential. With large presynaptic depolarizations, which produced the biggest i.p.s.p.s, there was some reduction in the amplitude and increase in the duration of the action potential. 5. Following a step depolarization of the presynaptic cell, the size of successive i.p.s.p.s increased with a time constant of about 1 sec. Upon repolarization the i.p.s.p.s decreased in amplitude to the original level. 6. stimulation of one HN cell also gives rise to an i.p.s.p. in its contralateral homologue (Thompson & Stent, 1976c). Trains of i.p.s.p.s produced in this way hyperpolarized at HN cell to such an extent that the size of the synaptic potential it evoked in an HE cell was reduced. 7. Thus, an HN interneurone inhibitis transmission between the contralateral HN and HE cells presynapitcally in addition to inhibiting directly the ipsilateral HE motoneurone.

Further surgical management of gastric ulcer with unsuspected malignant change

This paper considers the further surgical management of patients who have had a gastric ulcer removed which was apparently benign but which on subsequent histological examination has proved to be a carcinoma. A retrospective review of 59 such patients has been undertaken. A non-radical partial gastrectomy was performed in the first instance on all these patients; 24 of them had a second operation once the correct diagnosis had been reached and 35 had no further surgery. These two groups are compared. The overall 5-year survival in the non-revisional group was only 23% compared with 56% in those treated by a second operation. It is thought that revisional surgery should be undertaken within 6-8 weeks, provided the age and general condition of the patient are satisfactory. Since 1970 the routine use of fibreoptic endoscopy and biopsy has virtually eliminated the problem.