Showing papers by "University of Western Australia published in 1989"

Plasticity of frequency organization in auditory cortex of guinea pigs with partial unilateral deafness.

Abstract: We have examined the effect of restricted unilateral cochlear lesions on the orderly topographic mapping of sound frequency in the auditory cortex of adult guinea pigs. These lesions, although restricted in spatial extent, resulted in a variety of patterns of histological damage to receptor cells and nerve fibres within the cochlea. Nevertheless, all lesions resulted in permanent losses of sensitivity of the cochlear neural output across a limited frequency range. Thirty-five to 81 days after such damage to the organ of Corti, the area of contralateral auditory cortex in which the lesioned frequency range would normally have been represented was partly occupied by an expanded representation of sound frequencies adjacent to the frequency range damaged by the lesion. The thresholds at their new characteristic frequencies (CFs) of clusters of cortical neurones in these regions were close to normal thresholds at those frequencies (mean difference across all animals was 3.8 dB). In a second series of experiments, the responses of neurone clusters were examined within hours of making similar cochlear lesions. It was found that shifts in CF toward frequencies spared by the lesions could occur, but thresholds were greatly elevated compared to normal (mean difference was 31.7 dB in five animals). The emergence of sensitive drive in such regions after prolonged recovery periods in lesioned animals thus suggests that the auditory cortical frequency map undergoes reorganization in cases of partial deafness. Some features of this reorganization are similar to changes reported in somatosensory cortex after peripheral nerve injury, and this form of plasticity may therefore be a feature of all adult sensory systems.

Dietary folate as a risk factor for neural-tube defects: evidence from a case-control study in Western Australia.

Abstract: A population-based case-control study was conducted to test the hypothesis that the risk of the occurrence of neural-tube defects in infants with no other birth defects (isolated neural-tube defects) is associated inversely with the maternal dietary intake of free and/or total folate in early pregnancy. Information was collected from the mothers of 77 case subjects with isolated neural-tube defects who were born in Western Australia from 1982 to 1984, from the mothers of 77 control subjects with birth defects other than neural-tube defects (control group 1) and from the mothers of 154 control subjects with no birth defects (control group 2). The case and control subjects were matched individually by the date of the mother's last menstrual period. Odds ratios were adjusted for a number of potentially-confounding variables, such as the country of birth of the parents, paternal social class, previous pregnancy outcome, interval between index and previous pregnancy and pregnancy order. Crude and adjusted odds ratios showed a protective effect of an increasing intake of free folate in the first six weeks of pregnancy. Adjusted odds ratios, with reference to the lowest quartile of intake, (and their 95% confidence intervals) were 0.72 (0.25-2.08), 0.37 (0.11-1.23) and 0.31 (0.10-0.97) for quartiles 2-4 when control group 1 was used, and 0.44 (0.17-1.13), 0.34 (0.13-0.90) and 0.16 (0.06-0.49) when control group 2 was used. Similar, but weaker, trends were seen when total folate intake was the exposure variable. These findings support the hypothesis that the dietary intake of folate in early pregnancy protects against the occurrence of isolated neural-tube defects in infants. Measures of postpartum dietary folate and of postpartum serum and red-cell folate levels showed no association with the occurrence of neural-tube defects in infants.

Soil disturbance reduces the infectivity of external hyphae of vesicular—arbuscular mycorrhizal fungi

Abstract: SUMMARY We conducted two glasshouse experiments to determine the effect of soil disturbance on the infectivity of external hyphae of vesicular–arbuscular (VA) mycorrhizal fungi. A nylon mesh was used to exclude plant roots while allowing fungal hyphae to grow into soil contained by the mesh. Hyphae of VA mycorrhizal fungi that had been separated from the original host plant root were still able to colonize bioassay plants rapidly and extensively. However, disturbance of the soil inside the mesh, by mixing for 1 min, almost eliminated subsequent VA mycorrhiza formation in that soil. Damage to the soil hyphal network by soil disturbance may contribute to the losses in mycorrhizal infectivity that have been observed after mining and cultivation.

A biomechanical analysis of the sticking region in the bench press.

Abstract: The performance of ten elite powerlifters were analyzed in a simulated competition environment using three-dimensional cinematography and surface electromyography while bench pressing approximately 80% of maximum, a maximal load, and an unsuccessful supramaximal attempt. The resultant moment arm (from the sagittal and transverse planes) of the weight about the shoulder axis decreased throughout the upward movement of the bar. The resultant moment arm of the weight about the elbow axis decreased throughout the initial portion of the ascent of the bar, recording a minimum value during the sticking region, and subsequently increased throughout the remainder of the ascent of the bar. The electromyograms produced by the prime mover muscles (sternal portion of pectoralis major, anterior deltoid, long head of triceps brachii) achieved maximal activation at the commencement of the ascent phase of the lift and maintained this level essentially unchanged throughout the upward movement of the bar. The sticking region, therefore, did not appear to be caused by an increase in the moment arm of the weight about the shoulder or elbow joints or by a minimization of muscular activity during this region. A possible mechanism which envisages the sticking region as a force-reduced transition phase between a strain energy-assisted acceleration phase and a mechanically advantageous maximum strength region is postulated.

Dynamics of brain electrical activity.

Abstract: In addition to providing important theoretical insights into chaotic deterministic systems, dynamical systems theory has provided techniques for analyzing experimental data. These methods have been applied to a variety of physical and chemical systems. More recently, biological applications have become important. In this paper, we report applications of one of these techniques, estimation of a signal's correlation dimension, to the characterization of human electroencephalographic (EEG) signals and event-related brain potentials (ERPs). These calculations demonstrate that the magnitude of the technical difficulties encountered when attempting to estimate dimensions from noisy biological signals are substantial. However, these results also suggest that this procedure can provide a partial characterization of changes in cerebral electrical activity associated with changes in cognitive behavior that complements classical analytic procedures.

Atrial fibrillation and mortality in an elderly population.

Abstract: Prospective data from Busselton, Western Australia, collected during triennial surveys from 1966-81 with follow-up of subjects to 1983, showed that atrial fibrillation (AF) was frequent in elderly people and associated with increased mortality. Of 1770 people aged over 60 years, 40 were in atrial fibrillation when first seen and a further 47 developed it during follow-up. Atrial fibrillation was positively associated with angina, history of a myocardial infarction and left bundle branch block. Relative mortality in those with atrial fibrillation compared with those without it, was 1.92 for all causes, 1.82 for death from cardiovascular causes (excluding stroke) and 3.78 for deaths from stroke, after adjustment by proportional hazards regression for confounding effects of age, sex, history of a myocardial infarction, an abnormal electrocardiogram, angina, cholesterol level systolic blood pressure and Quetelet's Index (weight/height2). The excess relative mortality declined with increasing age for both women and men. This raised relative mortality remained constant with time from the first detection of AF for all causes and cardiovascular causes but appeared to increase with time from detection for stroke death. The risk of death from stroke was greatest in the younger women. The observed risk of death from stroke in patients with AF suggests that anticoagulant use should be considered in selected patients.

Back injuries to fast bowlers in cricket: a prospective study.

Abstract: Eighty-two high performance young male fast bowlers (mean age 16.8 years) were tested immediately prior to the season for selected kinanthropometric and physiological data. Subjects were also filmed both laterally (200 Hz) and from above (100 Hz) while bowling so that their front foot impacted a force platform during the delivery stride. The players then completed a log book over the ensuing season that detailed their training and playing programmes. All cricket related injuries over this season were assessed by a sports physician who used computerized tomography to assist in the diagnosis of spinal injuries. At the completion of this season the players were grouped according to their injury status (Group 1--bony injury to a vertebra; Group 2--soft tissue injury to the back that caused the player to miss at least one game, and Group 3--no injuries). A one-way analysis of variance was used to identify if any variables were significantly (P less than 0.05) different between the three groups, and a Scheffe post hoc comparison was used to determine which groups were significantly different. Eleven per cent of the players sustained a stress fracture to a vertebra(e) (L4 to S1), while 27 per cent sustained a soft tissue injury to the back. Bowlers with a low longitudinal foot arch were more likely to develop a stress fracture than those with a high arch. Shoulder depression and horizontal flexion strength for the preferred limb and quadriceps power in the non-preferred limb were also significantly related to back injuries. Results suggest that bowlers with the above physical characteristics, who bowl with these biomechanical techniques for extended periods, are predisposed to back injuries.

Ia-positive dendritic cells form a tightly meshed network within the human airway epithelium.

Abstract: In this report we have employed an alternative tissue-sectioning procedure which provides a plan view of intra-epithelial cell populations within the airway wall. Immunoperoxidase staining of such sections for class II MHC (Ia) antigen revealed the presence of a highly developed intra-epithelial network of Ia-positive dendritic cells, which was not evident employing conventional cross- or longitudinal tissue sections. This finding has important implications for the study of mechanisms underlying allergic and infectious diseases of the respiratory tract.

Towards a New Typology of Urban Planning Theories

Abstract: Urban planning theory has been widely criticised by academics and practitioners as being confused and impractical. In this review paper a tentative first step to remedy the situation is proposed, o...

Mitochondrial-dna variation in the crested newt superspecies: limited cytoplasmic gene flow among species.

Abstract: The crested newt has a widespread European distribution and encompasses four taxa recently elevated to full species: Triturus cristatus, T. carnifex, T. dobrogicus, and T. karelini. These are distinct on morphological, chromosomal, and isozymic grounds and have fairly sharp transition zones. A widespread survey (12 countries, 49 geographic sites, 210 individuals) of mtDNA variation (20-27 restriction enzyme sites mapped per individual) was made in order to 1) correlate mtDNA variation with morphological features defining the species, 2) determine the degree of differentiation within and among species, and 3) detect any introgression among species. The mtDNAs of these species were clearly differentiated (d = 3.9-7.1%). Additionally, geographic structuring was observed within T. carnifex and T. karelini, each displaying two divergent mitochondrial genome types (d = 3.5% and 4.7%, respectively). The other two (more northerly distributed) species were genetically homogeneous over most (T. cristatus) or all (T. dobrogicus) of their ranges. In the case of T. cristatus, one may infer bottlenecking as a result of Pleistocene glaciation events. This may also apply in part to T. dobrogicus, but high population connectedness and gene flow in this lowland river species may alone be sufficient for homogenization of mtDNA. Patterns of mtDNA variation were largely concordant with morphology; some interspecific mitochondrial gene flow was observed, but only close to or in the transition zones. Analyses of mapped restriction-site data by UPGMA and parsimony methods (using the closely related T. marmoratus as an outgroup) produce very similar dendrograms. The levels of divergence found concur with the systematics of the group, but the differentiation within T. carnifex and T. karelini is notable.

Fiscal decentralization and government size: An extension

Abstract: This paper analyzes one method governments employ to circumvent the discipline of a competitive system of fiscal federalism — intergovernmental collusion in the form of intergovernmental grants. Grants, it is argued, serve to encourage the expansion of the public sector by concentrating taxing powers in the hands of the central government and by weakening the fiscal discipline imposed on governments forced to self-finance their expenditures. The results reported suggest that intergovernmental grants do encourage growth in the public sector. The results offer further support for the use of monopoly government assumptions in public sector modeling.

Hyphae of a vesicular—arbuscular mycorrhizal fungus maintain infectivity in dry soil, except when the soil is disturbed

Abstract: SUMMARY We examined the hypothesis that hyphae of a VA mycorrhizal fungus in dry soil remain infective, but that the infectivity decreases if the soil is disturbed. We used split-pots, and sealed cylinders of nylon mesh, to create volumes of dry soil which contained hyphae of Acaulospora laevis Gerd. and Trappe that were attached, outside the mesh, to roots of living plants of Acacia satigna. (Labill.) H. Wendl. After the soil was dried in situ, the hyphae were detached from the roots without soil disturbance, or the soil containing the hyphae was disturbed. The infectivity of the hyphae after these treatments was then compared with that of intact hyphae. External hyphae of A. laevis remained highly infective in soil in which the matric potential had reached −21 MPa. Hyphae detached from the original host plant roots were equally infective. However, disturbance of the dry soil containing the external hyphae severely reduced the infectivity of the hyphae. After fluorescent staining, fungal structures with fluorescing nuclei were readily visible both within, and attached to, roots of A. Saligna which had no fluorescing nuclei.

Important dimensions of strategic issues: separating the wheat from the chaff*

Abstract: Decision-makers in organizations use dimensions implicitly or explicitly to sort strategic issues. This article compares the dimensions implied by three literatures and dimensions generated by an empirical study. While some similarities are identified, there are striking differences between what the literature assumes and what dimensions decision-makers in the NY/NJ Port Authority use to sort issues. Implications for theories of decision-making and interpretation in organizations are discussed.

Crustal-scale shear zones and their significance to Archaean gold mineralization in Western Australia

Abstract: Many large Archaean epigenetic gold deposits show a broad spatial relationship to regional lineaments in greenstone belts, although in detail they are sited in subsidiary brittle-ductile fault structures. Fluids, originating from a deep source, follow a complex path and re-equilibrate with different lithologies and with metamorphic fluid during migration to higher crustal levels. Temperature and pressure conditions at or below the amphibolite/greenschist metamorphic boundary, where most gold deposits are located, favour the establishment of brittle-ductile and brittle subsidiary structures, the preferred structural setting of gold deposits. Physical gradients between the regional ductile structures and more brittle subsidiary structures ensure transient, strongly localized, fluid flow into the latter, where lower temperatures and suitable host rocks with high Fe/(Fe + Mg) ratios favour gold-deposition. The multi-source origin and continuous re-equilibration of the fluid with crustal rock, which includes granitoid and greenstone-belt lithologies of different ages, is reflected in the diverse isotopic and geochemical signature of the gold deposits.

Milk lactose, citrate, and glucose as markers of lactogenesis in normal and diabetic women

Abstract: A study was undertaken to define an appropriate marker of lactogenesis II (the onset of copious milk secretion) in mothers, and to determine the effect of diabetes on this marker. Changes in the concentrations of three milk components--lactose, citrate, and glucose--were measured in 38 normal mothers and 6 type I diabetic mothers up to 10 days after birth. Milk yield was measured in 12 of the normal mothers, and all mothers were asked to note the time of milk "coming in" (the feeling of overfullness of the breasts). The average concentrations of lactose, citrate, and glucose in milk were low for the first 24 h after birth, then between 24 and 48 h after birth there was a rapid increase in the concentrations of lactose and citrate, and this transitional period was followed by a plateau period that began between 60 and 84 h after birth. For individual mothers the transitional period for citrate began 32 +/- 9 h (n = 13) and finished 77 +/- 10 h (n = 17) after birth, and for lactose the transitional period finished at 53 +/- 12 h (n = 29) after birth. For diabetic mothers these times were significantly later. The average 24-h milk intake by infants increased from 82 to 556 ml/24 h between 24 and 144 h after birth. Milk intakes were correlated with the concentration of lactose (r = 0.52, n = 51, p less than 0.001), citrate (r = 0.47, n = 47, p less than 0.001), and glucose (r = 0.69, n = 50, p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Islands in the interior: a model for the colonization of Australia's arid zone

Abstract: A colonization model is proposed to explain the timing of human occupation in different regions of the arid zone and the reasons for inferred demographic changes through time. A biogeographic approach views changes in human economy and technology against the backdrop of climatic oscillations of the last 40,000 years. This model stands in strong contrast to that of the ‘conservative desert culture’ proposed by Gould, which has become untenable as data from arid zone excavations are increasingly argued to reflect significant changes in human economy, technology and demography through time. The results of regional survey and excavation from the Pilbara and sandy deserts of north-west Australia, from central Australia, the Flinders Ranges and adjacent dunefields and from semi-arid Queensland suggest that the occupation of the arid zone from the late Pleistocene on is likely to have been a highly dynamic process. The notion of a stable human adaptation to the diverse landforms and environments of the arid zone finds little support in the archaeological record.

The effect of body reserves at farrowing on the reproductive performance of first-litter sows

Abstract: The level of body reserves in first-litter sows was manipulated by giving gilts one of three levels (high (H), medium (M) or low (L)) of food from selection (44 kg live weight) to parturition. The aim of this experiment was either to maintain or to mobilize these reserves during lactation (31·4 days) by feeding sows to appetite (high (H)) or 2·0 kg/day (low (L)).When the level of body reserves was increased prior to farrowing (171 kg live weight, 32 mm backfat) sows had a lower voluntary food intake during lactation than those animals that farrowed with a low level of body reserves (126 kg live weight, 20 mm backfat) (H-H v. L-H, 3·4 v. 4·9 kg/day; P < 0·001). Both groups had a normal return to oestrous activity after weaning (mean interval between weaning and mating of 14 days) but the heavier animals mobilized more of their body reserves (H-H −30·7 kg live weight, -4·3 mm backfat; L-H -3·6 kg live weight +0·9 mm backfat; P < 0·001). When food intake during lactation was restricted to 2·0 kg/day the interval between weaning and mating was increased by 50% regardless of the level of body reserves present at farrowing. For the same animals, there were insufficient body reserves to support milk production at the same level as for those animals given food t o appetite.

Late Archean convergent margin tectonics and gold mineralization: A new look at the Norseman-Wiluna Belt, Western Australia

Abstract: On a world scale, the most important hydrothermal gold deposits occur either in Late Archean (ca. 2700 Ma) greenstone belts or at late Paleozoic to Quaternary convergent plate boundaries. In the latter environments, epithermal and porphyry-hosted deposits form during subduction-related magmatism in volcanic arcs, and deep-level meso- thermal deposits form during deformation in continental margin orogenic belts. The mesothermal deposits are similar to Archean gold deposits in greenstone belts such as the Norseman-Wiluna Belt in Western Australia. We here suggest that this similarity exists because the Norseman-Wiluna Belt is an orogenic belt with a tectonic history similar to that of younger mineralized convergent margins, such as the North American Cordillera. It is most likely that the Norseman-Wiluna Belt resulted from the interaction of lithospheric plates during the major period of continental growth and stabilization that occurred in the Late Archean, the distribution of gold mineralization being controlled by convergent margin tectonics.

Descending projections from auditory brainstem nuclei to the cochlea and cochlear nucleus of the guinea pig.

Abstract: Projections from auditory brainstem nuclei to the cochlear nuclei in the guinea pig were studied by injection of two retrograde fluorescent neuronal tracers. For seven experiments fast blue was injected into the scala tympani of one cochlea and diamidino yellow was injected into dorsal or anteroventral cochlear nucleus of the same side. The results show that the efferent projections to the cochlea and cochlear nucleus generally form two separate neuronal systems even though they share many common nuclei of origin. The largest projections to the cochlear nucleus come bilaterally from the lateral and ventral nuclei of the trapezoid body. Other nuclei, the lateral superior olive, the ventral nucleus of the lateral lemniscus, the dorsomedial periolivary nuclei, and the medial nucleus of the trapezoid body showed an ipsilateral bias in their projections to the cochlear nucleus. An upper limit of 3.5% of the medial system olivocochlear efferent neurones projecting to the cochlea were labelled with both diamidino yellow and fast blue, suggesting that few efferent neurones projecting to the cochlea send collaterals to the cochlear nucleus in this species. However, the site of medial system olivocochlear efferent collateral terminations is the granule cell area for the cat, mouse, and gerbil. When diamidino yellow was injected in the superficial layers of the cochlear nucleus, including the superficial granule cell layer of the ventral cochlear nucleus, approximately 3.6% of medial system olivocochlear efferents projecting to the cochlea sent collaterals to the cochlear nucleus. In three animals fast blue was injected into the cochlear nucleus and diamidino yellow into the cochlea. These experiments revealed a greater proportion of the medial system olivocochlear efferents projecting to the cochlea sending collaterals to the cochlear nucleus, but this proportion was still less than 10%. These results were confirmed by the extracellular injection of horseradish peroxidase into the intraganglionic spiral bundle. Only three medial system olivocochlear efferents were observed to send collaterals to the cochlear nucleus. This number was less than 10% of all labelled medial system fibres. Although these experiments suggest that in the guinea pig the number of olivocochlear efferents sending collaterals to the cochlear nucleus is considerably smaller than is found for the cat, mouse, and gerbil, it is not possible with the current experimental procedures to conclude whether the results are due to species or methodological differences.

Macrophages: Current Views on Their Differentiation, Structure, and Function

Abstract: Macrophages are large mononuclear phagocytes that represent the major differentiated elements of the mononuclear phagocytic system. They arise from distinct progenitors in the bone marrow, and their immediate precursors, the monocytes, emigrate from the vascular compartment into many tissues and organs where they develop into mature macrophages. The latter display diverse morphological and functional characteristics, depending on the environmental stimuli that they receive. This phenotypic heterogeneity is, therefore, the final consequence of a series of down-regulation of some cellular processes and the up-regulation of others. The kinetics of the production of macrophages and their participation in various physiological and pathological phenomena is the subject of this review.

Stimulus-related potassium changes in the organ of Corti of guinea-pig.

Abstract: 1. Potassium concentration was measured with double-barrelled K+-selective microelectrodes within the organ of Corti in the first turn of the guinea-pig cochlea. 2. Penetration of the electrode from scala tympani through the basilar membrane was accompanied by an increase in K+ resting level from 3.0 mmol/l in perilymph to 3.4 mmol/l in cortilymph (n = 8). K+ resting level was not significantly different in various extracellular regions of the organ of Corti. On penetration of the cuticular plate, the K+ level reached 140 mmol/l simultaneously with the occurrence of a +80 mV endocochlear potential. Impalement of hair cells and supporting cells was accompanied by an increase in K+ level, but intracellular K+ level was not systematically measured. 3. Stimulation with pure tones over the frequency range 500 Hz to 25 kHz produced changes in the K+ level in the organ of Corti. The magnitude of these changes was dependent on stimulus frequency and intensity. At high sound intensities the K+ level in the tunnel of Corti could increase by typically 1 mmol/l, while a maximum increase of 3 mmol/l with respect to the resting level was observed immediately adjacent to inner hair cells. 4. During brief exposures to moderate intensity, pure tone acoustic stimulation (10 s, less than 80 dB SPL (sound pressure level] of frequency 4 kHz or greater the K+ level in the extracellular fluid of the organ of Corti rose monotonically to a steady peak level. On cessation of the stimulus the K+ level fell monotonically with a time constant of about 2 s to a level close to the pre-stimulus level. In some cases this level was slightly above the pre-stimulus level. 5. For brief exposures to moderate intensity sound (10 s, less than 80 dB SPL) the extracellular potential in the organ of Corti became more positive. The amplitude of this sound-evoked change adapted during stimulation to a level approximately one-fifth of its initial value. Upon cessation of the stimulus the potential fell transiently below its pre-stimulus level, before recovering to that level. The time constant of these changes was between 2 and 3 s. 6. Iso-response tuning curves for the sound-evoked elevation in K+ level in the organ of Corti in animals in good condition were similar to iso-rate tuning curves for primary afferent fibres reported previously.(ABSTRACT TRUNCATED AT 400 WORDS)

Myoclonus associated with treatment with high doses of morphine: the role of supplemental drugs.

Abstract: OBJECTIVE--To estimate the prevalence of important side effects in patients with malignant disease who were receiving high doses of morphine as part of their palliative treatment. DESIGN--Data on patients were collected over 12 months. SETTING--Two palliative care units in Western Australia. PATIENTS--19 Patients with malignant disease who were receiving morphine either subcutaneously or orally as the main analgesic. 10 Patients receiving a total daily dose of morphine of at least 500 mg orally or 250 mg parenterally were enrolled in the study. The other 9 patients were enrolled after an important problem thought to be related to the morphine had been identified. All of the patients were taking drugs to supplement the treatment. INTERVENTIONS--The dose of morphine or route of administration, or both, was changed in three patients. MAIN OUTCOME MEASURE--Determination of the prevalence of side effects in the patients. Assessment of the relation of any side effects with the supplemental drugs taken by the patients. MAIN RESULTS--Plasma morphine and electrolyte concentrations were measured and a full history taken for each patient. Thirteen of the 19 patients had an important side effect; 12 of them had myoclonus and one had hyperalgesia of the skin. Plasma morphine concentrations were similar in patients with and without myoclonus, ranging from 158 to 3465 nmol/l and 39 to 2821 nmol/l respectively. Eight of the patients with side effects were taking an antipsychotic drug concurrently compared with none of those without side effects. A greater proportion of patients with side effects were taking the antinauseant drug thiethylperazine (6/13 v 2/6) and at least one non-steroidal anti-inflammatory drug (10/13 v 2/6), whereas a smaller proportion were taking a glucocorticosteroid (3/13 v 4/6). The estimated prevalence of important side effects in the total population of patients receiving palliative treatment in the two units was 2.7-3.6%. CONCLUSIONS--Myoclonus as a side effect of treatment with morphine is more likely to occur in patients taking antidepressant or antipsychotic drugs as antiemetics or as adjuvant agents or non-steroidal anti-inflammatory drugs for additional analgesia. If a patient develops myoclonus the best approach may be to change the supplemental treatment.

Autoradiographic Localization of Beta-Adrenoceptors in Asthmatic Human Lung

Abstract: The autoradiographic distribution and density of beta-adrenoceptors in human non-diseased and asthmatic bronchi were investigated using [125I]iodocyanopindolol (I-CYP). Analysis of the effects of the beta-adrenoceptor antagonists on I-CYP binding demonstrated that betaxolol (20 nM, beta1-selective) had no significant effect on specific grain density in either nonasthmatic or asthmatic human bronchus, whereas ICI-118551 (20 nM, beta2-selective) inhibited I-CYP binding by 85 ± 9% and 89 ± 3%, respectively. Thus, homogeneous populations of beta2-adrenoceptors existed in bronchi from both sources. Large populations of beta-adrenoceptors were localized to the bronchial epithelium, submucosal glands, and airway smooth muscle. Asthmatic bronchial tissue featured epithelial damage with exfoliated cells associated with luminal mucus plugs. A thickened basement membrane and airway smooth muscle hyperplasia were also evident. High levels of specific I-CYP binding were also detected over asthmatic bronchial smooth mu...