Mapping epitope specificities of monoclonal antibodies to thyroid peroxidase using recombinant antigen preparations.

Five separate monoclonal antibodies (MoAbs) to human thyroid peroxidase (hTPO) were raised by immunising Balb/c mice with hTPO purified from detergent solubilised thyroid microsomes by high performance liquid chromatography (HPLC). The epitope specificities of these MoAbs were determined by assessing their ability to bind to purified recombinant fusion protein fragments of human TPO (TPO(r)) generated in E. coli. A total of seven small overlapping fragments (averaging 104 amino acid residues) of hTPO, encompassing over 90% of the extracellular region of the molecule, were generated as glutathione S-transferase (GST) fusion proteins. The sequential epitopes on TPO(r) recognised by these MoAbs were analysed by both immunoblotting and enzyme linked immunosorbent assay (ELISA). Two different MoAbs (A4 and A5) recognised sequential epitopes within the TPO(r) preparation termed R1a + b (residues 1-160) and more specifically, in the case of MoAb A4, within the subfragment R1b (residues 70-160). The inability of the other MoAbs (A1-A3) to recognise recombinant fragments, suggests they either recognise conformational determinants on the TPO molecule or epitopes that are present on the small regions of the TPO molecule which have not been expressed as recombinant proteins.

Inhibition of rat spinal cord dorsal horn neurons by non-segmental, noxious cutaneous stimuli.

Extracellular single unit recordings were obtained from spinal cord dorsal horn neurons in halothane-anesthetized rats. Inhibitory effects induced by noxious mechanical or electrical stimuli applied to a remote area of the body surface were assessed on the spontaneous or evoked activity of these cells. Noxious mechanical stimulation inhibited 59% of the cells receiving nociceptive inputs (wide dynamic range and nociceptive specific) but only 5% of the other cell types. Inhibition produced by mechanical stimulation lasted for the full duration of stimulus application (up to 30 s) whereas inhibition produced by electrical stimulation lasted less than 500 ms. Increasing the depth of anesthesia was found to depress or abolish the inhibition.

Transplantation of human sympathetic neurons and adrenal chromaffin cells into parkinsonian monkeys: no reversal of clinical symptoms.

Cultured human fetal sympathetic ganglion explants or adrenal chromaffin cell aggregates were implanted into the left striatum of monkeys whose left nigrostriatal pathway had been lesioned with the neurotoxin MPTP. There was no clinical reversal of parkinsonian symptoms and PET scans did not show increased striatal fluorodopa uptake from pre-implant levels. At sacrifice, left striatal contents of dopamine were not statistically different from MPTP-treated but non-implanted controls. Histological examinations revealed pockets of extrinsic cells which were found at the end of needle tracks. There was no evidence of immune rejection. The extrinsic cells did not stain for tyrosine hydroxylase or neurofilament, suggesting that they were not dopaminergic neurons. The failure to reverse clinical parkinsonian symptoms highlights the stage of infancy of neural implantation in Parkinson's disease.

Estimation and reduction of risk to hearing: the background and a case study.

For noise exposure varying in both level and duration, current noise criteria are inadequate but, by adapting methods presently available, an equivalent continuous level can be calculated from which the risk to hearing can be assessed. The predicted effects on hearing compare favourably with measured values. These methods are used to predict an 'acceptable' noise limit for the variable noise environment on the agricultural tractor. Methods of noise reduction for the tractor are outlined along with other approaches to hearing preservation.

The ergonomics of open-fronted C-frame presses.

This study comprised three phases: an industrial survey of press design and operation; a shopfloor evaluation of performance with a modified press and its comparison with the original design; and a laboratory simulation of the effects of three of the most pertinent ergonomics design factors. The survey showed that many features of press design were in disagreement with ergonomics criteria, often markedly so, and that these presented potentially important limitations to performance. The modified press layout produced evidence of superior performance in comparison with the original layout and this was substantiated by the simulation particularly in terms of the reach required to the die.

A study of physiological and work study indices of forestry work.

Reasons for the use of physiological methods of assessment in addition to classical work study methods are given for the case of manual work. A study of use of both assessment processes with regard to a series of forestry tasks is presented. Poor correlations between physiological and work study assessments were obtained and since the tasks were manual in nature it was presumed the physiological methods offered greater accuracy. A test study was used to support this view. Finally, the paper suggests a physiological index of manual effort, related to individual capacity, which might be capable of application in normal field work.

Soil carbon stocks and changes in the Republic of Ireland.

The soil carbon (C) stock of the Republic of Ireland is estimated to have been 2048 Mt in 1990 and 2021 Mt in 2000. Peat holds around 53% of the soil C stock, but on 17% of the land area. The C density of soils (tCha(-1)) is mapped at 2 km x 2 km resolution. The greatest soil C densities occur where deep raised bogs are the dominant soil; in these grid squares C density can reach 3000 tCha(-1). Most of the loss of soil C between 1990 and 2000-up to 23 MtC (1% of 1990 soil C stock)-was through industrial peat extraction. The average annual change in soil C stocks from 1990 to 2000 due to land use change was estimated at around 0.02% of the 1990 stock. Considering uncertainties in the data used to calculate soil C stocks and changes, the small average annual 'loss' could be regarded as 'no change'.

Catecholamine-induced changes in ion transport in short-circuited frog skin and the effect of beta-blockade.

1. A method for measuring bidirectional Cl fluxes has been used to estimate net Cl movements in short-circuited frog skin and to compare these with the short-circuit current (Isc) and Na fluxes. 2. In some experiments bidirectional fluxes of both Na and Cl were measured simultaneously. It was found that the algebraic sum of the net fluxes of these two ions did not differ significantly from the values of Isc, either in untreated or catecholamine-treated skins, except for the half-hour period immediately after catecholamine addition. 3. The net effluxes of Cl produced by noradrenaline (1-6 X 10(-5)M), isoprenaline (8 X 10(-7)M) and adrenaline (6 and 15 X 10(-6)M) were of similar magnitude for each catecholamine. The magnitude of the Cl response measured as a flux ratio was related to a certain extent to the precatecholamine Cl conductance. 4. The net Na influx was increased by isoprenaline and reduced by noradrenaline. 5. Addition of the beta-adrenergic blocking agent oxprenolol (4-5 X 10(-5)M) to skins stimulated by catecholamine resulted in the disappearance of the net Cl movement and fall in skin conductance and Isc. This fall was similar in magnitude to, and correlated with the mean rise in Isc produced by isoprenaline, but of significantly greater magnitude in the case of noradrenaline. 6. The changes in Na influx were strongly associated with the changes in Isc following catecholamine addition. Similarly, the changes in Na efflux and Cl efflux were correlated, suggesting the Na fluxes to be dissociated, influx and efflux changes perhaps taking place at different loci. 7. Acetazolamide (1-2 X 10(-4)M), added either before or during the noradrenaline stimulation, had no effect on the Cl efflux response. 8. The tissue exchange of Cl from the outside bathing medium after 4 hr was greater in catecholamine-stimulated skins than in those in which the response had been blocked by oxprenolol. 9. These findings were taken to support a model entailing a neutral NaCl pump resident in the mucous glands and an epithelial Na pump enhanced by beta- and inhibited by alpha-adrenergic stimulation.

Spectral response patterns of auditory cortex neurons to harmonic complex tones in alert monkey (Macaca mulatta).

1. The auditory cortex in the superior temporal region of the alert rhesus monkey was explored for neuronal responses to pure and harmonic complex tones and noise. The monkeys had been previously trained to recognize the similarity between harmonic complex tones with and without fundamentals. Because this suggested that they could preceive the pitch of the lacking fundamental similarly to humans, we searched for neuronal responses relevant to this perception. 2. Combination-sensitive neurons that might explain pitch perception were not found in the surveyed cortical regions. Such neurons would exhibit similar responses to stimuli with similar periodicities but differing spectral compositions. The fact that no neuron with responses to a fundamental frequency responded also to a corresponding harmonic complex missing the fundamental indicates that cochlear distortion products at the fundamental may not have been responsible for missing fundamental-pitch perception in these monkeys. 3. Neuronal responses can be expressed as relatively simple filter functions. Neurons with excitatory response areas (tuning curves) displayed various inhibitory sidebands at lower and/or higher frequencies. Thus responses varied along a continuum of combined excitatory and inhibitory filter functions. 4. Five elementary response classes along this continuum are presented to illustrate the range of response patterns. 5. "Filter (F) neurons" had little or no inhibitory sidebands and responded well when any component of a complex tone entered its pure-tone receptive field. Bandwidths increased with intensity. Filter functions of these neurons were thus similar to cochlear nerve-fiber tuning curves. 6. "High-resolution filter (HRF) neurons" displayed narrow tuning curves with narrowband widths that displayed little growth with intensity. Such cells were able to resolve up to the lowest seven components of harmonic complex tones as distinct responses. They also responded well to wideband stimuli. 7. "Fundamental (F0) neurons" displayed similar tuning bandwidths for pure tones and corresponding fundamentals of harmonic complexes. This response pattern was due to lower harmonic complexes. This response pattern was due to lower inhibitory sidebands. Thus these cells cannot respond to missing fundamentals of harmonic complexes. Only physically present components in the pure-tone receptive field would excite such neurons. 8. Cells with no or very weak responses to pure tones or other narrowband stimuli responded well to harmonic complexes or wideband noise.(ABSTRACT TRUNCATED AT 400 WORDS)

Perception of the missing fundamental in nonhuman primates.

In preparation for neurophysiological experiments aimed at mechanisms of pitch perception, four rhesus monkeys were trained to press a button when the fundamental frequencies (missing or present) of two complex tones in a tone pair matched. Both tones were based on a five-component harmonic series. Zero to three of the lowest components could be missing in the first tone, while the second (comparison) tone contained all five harmonics. The range of fundamentals tested varied from 200 to 600 Hz. Three monkeys learned to match tones missing their fundamentals to comparison harmonic complexes with the same pitch, whereas the fourth monkey required the physical presence of the fundamental. Consideration of several cues available to the monkeys suggests that the animals could perceive the missing fundamental.

Effect of amiloride on catecholamine-induced changes in ion transport in short-circuited frog skin.

The effect of amiloride (10(-6) M), added either before or after the catecholamine, on the adrenaline- or isoprenaline-induced changes in short-circuit current and Na and Cl fluxes of isolated skin of Rana temporaria was investigated. At the catecholamine concentration used the increment in short-circuit was the same in the absence or presence of amiloride (ca. 7.1 neq.cm-2.min-1) and the amiloride inhibition was the same in the absence or presence of catecholamine (ca. 9.4 neq.cm-2.min-1). Amiloride inhibited the Na and Cl influxes of the control period (by --8.63 +/- 1.28 and --2.08 +/- 0.75 neq.cm-2.min-1, respectively) but did not prevent the increase of these fluxes on the addition of adrenaline. There was no evidence of amiloride inhibition of the Na and Cl effluxes. There was an association between the increase of Na efflux and net Cl efflux following adrenaline, which if secreted together by a neutral NaCl pump would not contribute to the increased short-circuit current. The increased short-circuit current was correlated with the increased Na influx throughout the experiment if allowance is made for the periods where there is a lag between the current and isotopic measurement (i.e., the period immediately after the addition of a drug). It is tentatively suggested that the catecholamine-induced increase in Na influx is not altered by the amiloride concentration used in this study. In addition the magnitude of the changes induced by catecholamine in the influx and efflux of both Na and Cl seem to be unaffected.

The dstribution of calcium-47 in the rat.

1. Plasma specific activities were measured at various times after the intravenous injection of calcium-47 in four different age groups of rats.2. The data may be represented as two power functions. The change in power function occurs at a set time which is significantly different in three of the age groups.3. Various bones, muscle and skin all show different uptakes of the calcium-47 and the change in the power function of the plasma data probably represents an equilibrium of the soft tissue calcium.

A complex tone code in the auditory cortex.

In the search for an objective measure of a biologically meaningful encoding scheme for cochlear implants, we recorded responses to tones from the alert auditory cortex. Neurons in the primary auditory field (A1) are typically characterized by filter characteristics resembling those of eighth nerve afferent fibers (filter neurons). In contrast, a different class of neurons has been found thus far only outside of the cochleotopic A1 array. These cells are sharply tuned to pure tones, and corresponding fundamental frequencies of harmonic complexes (F0 neurons). Thus these cells are specific for various tones of the same pitch. Sharpened pure- and complex-tone tuning can be accounted for by lateral inhibition. Time patterns for tonal and noise responses can vary dramatically.

Changing attitudes of medical teachers towards medical education.

If medical education is to improve, this is largely dependent upon the attitudes of clinical teachers towards their own teaching and their students' learning. The aims and objectives of our workshop method of medical teacher training therefore includes some in the affective domain. Based on the theory of cognitive dissonance the experience-linked practical problem solving approach of the workshop encourages behaviour change, presuming this to cause 'attitude change'. Testing by means of a specially constructed and validated Likert-type attitude scale shows that attitudes do improve significantly and consistently over the 5 days of our workshops. A follow-up study shows these effects to be maintained and taken back to the participants' own medical schools.

Training of medical teachers.

The need for teacher training in the health professions and the shortcomings of the usual methods of involving teachers in teaching strategies are discussed. An outline of a course employing a workshop method to overcome some of the shortcomings is given, based on the four years' experience of the course held at King's College Hospital Medical School.