Background In the UK and elsewhere, there is a growing policy and legislative imperative to ensure that people with intellectual disabilities are supported to develop relationships, including sexual ones. However, gay, lesbian and bisexual people with intellectual disabilities may have additional needs or face particular barriers in this area of their lives. They may require particular kinds of support from the staff who work with them. But how able, or willing, are staff in services to address these issues? Method As part of empirical, qualitative research, the authors carried out interviews with 71 staff in 20 intellectual disability services across the UK about their views and experiences of working with people with intellectual disabilities who were, or may have been, gay, lesbian or bisexual. Results The majority of staff interviewed said that they did not feel confident working in this area. A number of barriers to doing the work were identified including a lack of policy and training as well as the prejudice of staff and parents/carers. Conclusions The reticence of staff to engage with these issues needs addressing especially in the light of the emerging human rights of people with intellectual disabilities to develop sexual and intimate relationships.
SUMMARY1. A study has been made of the temperature changes associated with the passage of a single impulse in rabbit desheathed vagus nerves.2. The initial changes consist of an evolution of positive heat followed by a reabsorption of most of it; i.e. there is a phase of positive and a phase of negative heat production.3. The size of the positive heat, its time of onset, and the time of onset of the negative heat have been measured by an analogue method of analysis. In addition, these parameters, together with the size of the negative heat and the duration of both phases of initial heat, have been studied with the aid of a computer, and also by conventional heat block analysis.4. At about 50 C the measured positive heat is 7-2 ,tcal/g. impulse. It starts as soon as the compound action potential reaches the thermopile and lasts for about 107 msec.5. This positive heat decreases with increasing temperature, the ratio of heat at 40 C to that at 140 C being 1*86.6. The measured negative heat at about 50 C is 4-9 /ucal/g. impulse. It starts 102 msec after the onset of positive heat, and lasts for about 240 msec.7. When the sodium of Locke solution is replaced by lithium the positive heat is reduced by 19 %, but the negative heat is increased by 22 %.8. In potassium-free solutions the positive heat is hardly affected (increase of 5 %), but the negative heat is more than doubled. As a result the nerve may become briefly colder than its initial temperature by about 2 #0 C.9. The effect of sodium-deficient solutions on the positive heat is somewhat variable, but the negative heat is consistently diminished. 11. Replacement of most of the sodium of Locke solution by barium reduces or abolishes the negative heat, and increases the measured size of the positive heat nearly threefold.12. Veratrine (10-5 g/ml.) produces a nearly tenfold increase in the net positive heat.13. Ouabain (1 mM) and antimycin A (1 ,ug/ml.) applied for 30-60 min have little effect on the initial heat production.14. Over the temperature range 5-15°C, and for the ionic solution changes described above, there is close agreement in timing between the positive heat and the rising phase of the action potential, and between the negative heat and the falling phase.15. Because of the inevitable temporal dispersion of the action potential over the face of the thermopile, the observed temperature changes are smaller than those which occur at a single point in the nerve close to a stimulating electrode. The corrected value of the positive heat at 50 C is 24*5 ,ucal/g. impulse, while that of the negative heat is 22-2 ,lcal/g. impulse.16. The heats of mixing of the ions in solution that interchange during the action potential are much too small to account for the observed initial heats, but an exchange of ions associated with fixed charges might make a significant contribution to the heats.17. The condenser theory, according to which the positive heat represents the dissipation of electrical energy stored in the membrane capacity, while the negative heat results f...
A study was made of motoneuron firing rates and mechanical contractile parameters during maximum voluntary contraction of human hand muscles. A comparison of muscles that had been fatigued after a 60-s maximum voluntary contraction (MVC) with muscles that were cooled by approximately 5 degrees C showed that the contractile properties, in particular the rates of contraction and relaxation, were similarly affected in both conditions. In contrast, the motoneuron firing rate was affected differently by the two treatments. In the case of the fatigued muscles the motoneuron firing rate was reduced by 36%, as was expected from previous studies, but in the case of the cooled muscles, there was no significant change in the motoneuron firing rate. We conclude that the reflex reduction in the motoneuron firing rate seen in the fatigued muscle is not triggered directly by a change in the mechanical properties of the muscle.
It is well known that hypertonic solutions diminish, and in sufficient concentration abolish, the twitch of frog muscle, whereas hypotonic solutions within a certain range enhance the twitch (Overton, 1902;Fenn, 1936;Hodgkin & Horowicz, 1957). This paper describes some mechanical measurements made with muscles exposed to solutions up to the equivalent of three times the concentration of normal Ringer's solution, and to hypotanic solutions. METHODSAll the experiments described were made with sartorii of English frogs, male and female: no seasonal variations were noticed. Similar results were obtained with the sartorii of toads.Most of the experiments involved measurement of the speed of shortening or of the tension developed. Shortening was recorded by means of a light isotonic lever of low inertia bearing a vane which cast a shadow on a twin phototube (Hill, 1951). The potential change arising from movement of the shadow was amplified by a Kelvin and Hughes amplifier Type 6 and displayed on a smoked drum by a Kelvin and Hughes pen recorder Mk. V. Tension was recorded by means of an R.C.A. 5734 transducer triode and similarly displayed on a smoked drum or, when high amplification and speed were required, photographically from a cathode-ray tube.In early experiments muscles were mounted on a multi-electrode assembly to eliminate the effect of any possible change in the rate of propagation of the contractile wave. This was later found unnecessary and a simple holder bearing two platinum electrodes was adopted, exposing both faces of the muscle to the solution, thus allowing quicker equilibration. Stimulation was direct.The normal Ringer's solution was: (mM) NaCl, 115-5; KCI, 2-5; CaCl, 1-8. Hypotonic solutions were made by adding the calculated amount of distilled water. Hypertonic solutions were of two kinds in which the excess osmotic pressure was provided, (a) by sucrose and (b) by salts. 'Sucrose hypertonic Ringer' was made by dissolving solid sucrose in normal Ringer's solution, assuming 220 mM-sucrose to be isotonic. Salt-enriched solutions were made by dilution of stock solution of 10 x the concentration of standard Ringer's solution in all constituents. Buffering was provided by 2 mM sodium phosphate buffer at pH 7-2. Throughout this paper concentrations are expressed relative to Ringer's solution, e.g. 2-5 x R, or 07 x R. Where the word 'hypotonic' appears it is italicized to make it more easily distinguished from 'hypertonic'.Experiments were made at 00 C and in the region 18-20°C. There was no qualitative difference between results at the two temperatures.
The ‘initial’ heat production of a non-medullated nerve ( Maia ) has been reinvestigated with more rapid recording equipment than was previously available. In a single impulse at 0° C a positive heat production was observed averaging about 9 x 10 -6 cal/g nerve: this is rapid and is probably associated with the active phase of the impulse. It is followed by a rather slower heat absorption averaging about 7 x 10 -6 cal/g nerve and lasting for about 300 ms. Previous methods were too slow to do more than record the difference between the two, the ‘net heat’, viz. about 2 x 10 -6 cal/g nerve: this is about one-third greater at 0°C than at 18° C. Maia nerves contain fibres from 20 to 0.3 µ in diameter, and about half the heat is probably derived from fibres less than 3.0 µ . The velocities of impulses in them at 0° C vary from 1.4 to 0.1 m/s, so impulses reach the recording thermojunctions throughout a long interval. Thus the observed course of the heat production is the resultant of positive and negative components in different fibres, and a substantial part of each is masked. The real positive and negative heats, therefore, are substantially greater than those observed: on the most likely estimate of velocity distribution, in a single impulse at 0° C they are about 14 x 10 -6 cal/g and — 12 x 10 -6 cal/g, respectively. Heat production, like ionic interchange, is probably proportional to fibre surface, which in 1 g of Maia nerve is estimated as 10 4 cm 2 . If the fibre surface is taken as 50 Å thick, the heats just calculated, if reckoned per gram of surface material, are 2.8 x 10 -3 cal and — 2.4 x 10 -3 cal, respectively. The former is about the same as the heat produced per gram in a muscle twitch. During the passage of an impulse there is known to be an interchange of Na and K ions between the axoplasm and the outside fluid. When isotonic solutions of NaCl and KCl are mixed there is a production of heat. A substantial part of the heat during an impulse may be derived from the interchange of Na and K. Another part may be associated with chemical reactions occurring in the excitable membrane during the cycle of permeability change accompanying the passage of an impulse. The negative heat production is discussed. It cannot be connected with ‘pumping back’ the Na and K ions; this is a much slower process and anyhow would probably involve a positive heat production. It may be a sign of endothermic chemical reactions, representing a first (anaerobic) stage in recovery, which occur in the surface membrane following the completion of the permeability cycle. The question is considered whether the positive and negative phases of the heat production could be due to the discharge and recharge, during the action potential, of the condenser residing in the excitable membrane. The heats so calculated are of the right order of size, but on present evidence the time relations seem to be quite wrong. The amount of K which escapes per impulse from Maia nerve during slow repetitive stimulation at 0° C was measured. It depends greatly on frequency of stimulation; at ‘zero frequency’ it was about 9 X 10 -8 mole/g x impulse.
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