Showing papers by "University of Nottingham published in 1989"
TL;DR: Reduced glutathione and the shift of the iron (II)/iron (III) ratio in favor of iron ( III) suggest that these changes might contribute to pathophysiological processes underlying PD.
Abstract: The regional distributions of iron, copper, zinc, magnesium, and calcium in parkinsonian brains were compared with those of matched controls. In mild Parkinson's disease (PD), there were no significant differences in the content of total iron between the two groups, whereas there was a significant increase in total iron and iron (III) in substantia nigra of severely affected patients. Although marked regional distributions of iron, magnesium, and calcium were present, there were no changes in magnesium, calcium, and copper in various brain areas of PD. The most notable finding was a shift in the iron (II)/iron (III) ratio in favor of iron (III) in substantia nigra and a significant increase in the iron (III)-binding, protein, ferritin. A significantly lower glutathione content was present in pooled samples of putamen, globus pallidus, substantia nigra, nucleus basalis of Meynert, amygdaloid nucleus, and frontal cortex of PD brains with severe damage to substantia nigra, whereas no significant changes were observed in clinicopathologically mild forms of PD. In all these regions, except the amygdaloid nucleus, ascorbic acid was not decreased. Reduced glutathione and the shift of the iron (II)/iron (III) ratio in favor of iron (III) suggest that these changes might contribute to pathophysiological processes underlying PD.
1,392 citations
TL;DR: Results are consistent with a causative role for lipid peroxidation in the etiology of defective sperm function and also suggest a possible physiological role for the reactive oxygen species generated by human spermatozoa in mediating sperm-zona interaction.
Abstract: Recent studies have demonstrated that human spermatozoa are capable of generating reactive oxygen species and that this activity is significantly accelerated in cases of defective sperm function. In view of the pivotal role played by lipid peroxidation in mediating free radical damage to cells, we have examined the relationships between reactive oxygen species production, lipid peroxidation, and the functional competence of human spermatozoa. Using malondialdehyde production in the presence of ferrous ion promoter as an index of lipid peroxidation, we have shown that lipid peroxidation is significantly accelerated in populations of defective spermatozoa exhibiting high levels of reactive oxygen species production or in normal cells stimulated to produce oxygen radicals by the ionophore, A23187. The functional consequences of lipid peroxidation included a dose-dependent reduction in the ability of human spermatozoa to exhibit sperm oocyte-fusion, which could be reversed by the inclusion of a chain-breaking antioxidant, alpha-tocopherol. Low levels of lipid peroxidation also had a slight enhancing effect on the generation of reactive oxygen species in response to ionophore, without influencing the steady-state activity. At higher levels of lipid peroxidation, both the basal level of reactive oxygen species production and the response to A23187 were significantly diminished. In contrast, lipid peroxidation had a highly significant, enhancing effect on the ability of human spermatozoa to bind to both homologous and heterologous zonae pellucidae via mechanisms that could again be reversed by alpha-tocopherol. These results are consistent with a causative role for lipid peroxidation in the etiology of defective sperm function and also suggest a possible physiological role for the reactive oxygen species generated by human spermatozoa in mediating sperm-zona interaction.
1,171 citations
TL;DR: Estimates for the prevalence of self-reported hearing disability and measured hearing impairment as a function of age in the adult population of Great Britain are reported from two 2-stage surveys, with rigorous audiological assessment at the second stage.
Abstract: Estimates for the prevalence of self-reported hearing disability and measured hearing impairment as a function of age in the adult population of Great Britain (GB) are reported from two 2-stage surveys. The main study was conducted in Cardiff, Glasgow, Nottingham and Southampton, with rigorous audiological assessment at the second stage. A supplementary study used a sample representative of GB with simplified domiciliary audiological assessments. In the main study, neither stage showed any gross bias arising from the particular cities chosen; the estimates from the first stage are free of bias arising from non-response. The estimates from the second stage are relatively free of bias arising from non-attendance. For the present purposes, defining a 'significant' level of hearing impairment as at least 25 dBHL averaged over the frequencies 0.5, 1, 2, 4 kHz, 16% of the adult population (17-80 years) have a bilateral, and about one in four a unilateral or bilateral, hearing impairment. About 10% of the adult population (aged 17+) report bilateral hearing difficulty in a quiet environment.
504 citations
TL;DR: The results indicate that, even if dysphagia itself is not responsible for much excess mortality in acute stroke, it might still lead to complications which hamper functional recovery and show a significant inverse correlation with functional ability at 1 and 6 months.
Abstract: Data from 357 conscious stroke patients taking part in an acute intervention trial and assessed within 48 hours of the onset of symptoms, were used to investigate the prevalence and natural history of swallowing problems. Nearly 30% of patients with single-hemisphere strokes were initially found to have difficulty swallowing a mouthful of water, but in most of those who survived, the deficit had resolved by the end of the first week. Strong correlations were found between dysphagia and speech impairment (comprehension and expression) and with facial weakness, but there was no association with the side of the stroke. After controlling for other markers of overall stroke severity such as conscious level, urinary continence, white blood cell count and strength in the affected limbs, swallowing impairment still showed a significant inverse correlation with functional ability at 1 and 6 months. These results indicate that, even if dysphagia itself is not responsible for much excess mortality in acute stroke, it might still lead to complications which hamper functional recovery.
470 citations
TL;DR: The results suggest that schizophrenia may involve left‐sided abnormalities in the relationship between temporal glutamatergic and dopaminergic projections to amygdala, and are compatible with an overabundant glutamatorgic innervation of orbital frontal cortex in schizophrenia.
Abstract: Glutamatergic mechanisms have been investigated in postmortem brain samples from schizophrenics and controls. D-[3H]Aspartate binding to glutamate uptake sites was used as a marker for glutamatergic neurones, and [3H]kainate binding for a subclass of postsynaptic glutamate receptors. There were highly significant increases in the binding of both ligands to membranes from orbital frontal cortex on both the left and right sides of schizophrenic brains. The changes are unlikely to be due to antemortem neuroleptic drug treatment, because no similar changes were recorded in other areas. A predicted left-sided reduction in D-[3H]aspartate binding was refuted at 5% probability, but not at 10%. Previously reported high concentrations of dopamine in left amygdala were strongly associated with low concentrations of D-[3H]aspartate binding in left polar temporal cortex in the schizophrenics. The findings are compatible with an overabundant glutamatergic innervation of orbital frontal cortex in schizophrenia. The results also suggest that schizophrenia may involve left-sided abnormalities in the relationship between temporal glutamatergic and dopaminergic projections to amygdala.
386 citations
TL;DR: The role of melanocytes is investigated by studying its development in a mouse mutant, viable dominant spotting, which is known to have a primary neural crest defect leading to an absence of recognisable melanocytes in the skin, and this is the clearest demonstration yet of a role for migratory melanocytes other than their role in pigmentation.
Abstract: The stria vascularis of the mammalian cochlea is composed primarily of three types of cells. Marginal cells line the lumen of the cochlear duct and are of epithelial origin. Basal cells also form a continuous layer and they may be mesodermal or derived from the neural crest. Intermediate cells are melanocyte-like cells, presumably derived from the neural crest, and are scattered between the marginal and basal cell layers. The marginal cells form extensive interdigitations with the basal and intermediate cells in the normal adult stria. The stria also contains a rich supply of blood vessels. We investigated the role of melanocytes in the stria vascularis by studying its development in a mouse mutant, viable dominant spotting, which is known to have a primary neural crest defect leading to an absence of recognisable melanocytes in the skin. Melanocytes were not found in the stria of most of the mutants examined, and from about 6 days of age onwards a reduced amount of interdigitation amongst the cells of the stria was observed. These ultrastructural anomalies were associated with strial dysfunction. In the normal adult mammal, the stria produces an endocochlear potential (EP), a resting dc potential in the endolymph in the cochlear duct, which in mice is normally about +100 mV. In our control mice, EP rose to adult levels between 6 and 16 days after birth. In most of the mutants we studied, EP was close to zero at all ages from 6 to 20 days. Melanocyte-like cells appear to be vital for normal stria vascularis development and function. They may be necessary to facilitate the normal process of interdigitation between marginal and basal cell processes at a particular stage during development, and the lack of adequate interdigitation in the mutants may be the cause of their strial dysfunction. Alternatively, melanocytes may have some direct, essential role in the production of an EP by the stria. Melanocytes may be important both for normal strial development and for the production of the EP. We believe this is the clearest demonstration yet of a role for migratory melanocytes other than their role in pigmentation.
373 citations
TL;DR: Cancers detected by screening were at a less advanced pathological stage, but it is too early to show any effect of screening on mortality from colorectal cancer.
322 citations
TL;DR: In this article, the effects of afforestation on inputs of pollutants to catchments are illustrated by model calculations for inputs of sulphur and nitrogen to Kielder forest in northern England.
Abstract: Forests have long been considered as efficient sinks for atmospheric pollutants. The potential for large rates of deposition is provided by the turbulent structure of air above and within forest canopies. Large rates of deposition of pollutant gases, however, are only found for the very reactive gases HNO $\_3$ , HC $\_1$ and NH $\_3$ . In contrast, the pollutants SO $\_2$ and O $_3$ are deposited on forests and short vegetation at similar rates under the control of stomatal resistance. Deposition of sub-micrometre aerosol particles on forests appears to be inefficient but at high elevations in the United Kingdom (up to 500 m) these aerosols are frequently activated into cloud droplets in the size range 5-10 $\mu$ m (radius). These droplets are efficiently captured by forest canopies and this deposition pathway may make a large contribution to annual inputs at high elevation sites. The effects of afforestation on inputs of pollutants to catchments are illustrated by model calculations for inputs of sulphur and nitrogen to Kielder forest in northern England. Inputs of sulphur and nitrogen to this area as moorland are estimated at 17.5 kg ha $^{-1}$ (1 hectare = 10 $^4$ m $^2$ ) and 12.4 kg ha $^{-1}$ annually, respectively. Afforestation of the moorland increases sulphur and nitrogen inputs by 30 % and 90%, respectively.
316 citations
TL;DR: Autistic children were significantly worse than the non-autistic children at finding the odd person out and the odd facial expression of emotion out, and at labelling facial expressions of emotion, and this is consistent with other evidence for a specific perceptual abnormality in at least some children with autism.
Abstract: Ten autistic children were compared with 10 non-autistic children matched for chronological age and performance IQ on two tests of finding the odd face out of a set of photographs of faces, two tests of labelling photographs of fates, and a test of labelling photographs of common objects. The autistic children were significantly worse than the non-autistic children at finding the odd person out and the odd facial expression of emotion out, and at labelling facial expressions of emotion. They did no worse than the non-autistic children at labelling upside down faces or at labelling objects.
The results, which replicate the findings of Hobson (J. Child Psychol. Psychiat.27, 321–342, 671–680, 1986; Communication, 20, 12–17, 1986) are consistent with other evidence for a specific perceptual abnormality in at least some children with autism, the nature of which is discussed.
316 citations
TL;DR: In this article, a review points out confusion surrounding the concept and use of mental models from the viewpoints of both human factors and psychology, and the ways in which the notion is conceived according to the needs and approaches of different specialties.
Abstract: This review points out confusion surrounding the concept and use of mental models from the viewpoints of both human factors and psychology. Noted are the ways in which the notion is conceived according to the needs and approaches of different specialties, and the relationships of mental models to other forms of knowledge representation are considered. The manner in which the human factors community has and should utilize the concept in applications across a number of fields is addressed and discussed in relation to the psychological perspective.
312 citations
TL;DR: It is shown that both calpactin and calp actin heavy chain (p36) reconstitute secretion in permeabilized chromaffin cells in which secretion has been reduced as a result of leakage of cellular components, indicating that either calpACTin or p36 is essential for exocytosis.
Abstract: Stimulation of bovine adrenal chromaffin cells results in a rise in the concentration of cytosolic calcium which triggers the release of catecholamines by exocytosis. Several cytosolic proteins that bind to secretory granule membranes in a calcium-dependent manner have been implicated in exocytosis and some belong to a family of calcium-binding proteins, the annexins. One of these, calpactin, is a tetramer consisting of two heavy and two light chains (relative molecular masses 36,000 and 10,000 respectively) and can aggregate and fuse membranes in vitro in the presence of arachidonic acid. Calpactin is found at the cell periphery and is phosphorylated when chromaffin cells are stimulated. We show here that both calpactin and calpactin heavy chain (p36) reconstitute secretion in permeabilized chromaffin cells in which secretion has been reduced as a result of leakage of cellular components. This effect is inhibited by an affinity-purified antibody against p36. Secretion from permeabilized cells is inhibited by a synthetic annexin-consensus peptide, but not by a nonspecific hydrophobic peptide; this inhibition is reversed by p36. Our results indicate that either calpactin or p36 is essential for exocytosis.
TL;DR: Associations between walking speed and other variables have been investigated in a group of 67 women and 58 men aged between 65 and 90 years and living independently, and it was found that in men 44% of the variance in walking speed was accounted for by height, calf strength and the presence of health problems.
Abstract: Associations between walking speed and other variables have been investigated in a group of 67 women and 58 men aged between 65 and 90 years and living independently. In men, walking speed was related positively to calf strength, step-score (a measure of customary physical activity), hours spent in active leisure, height and weight, and negatively to age and the presence of health problems. In women, the relations were the same, with the exception of weight, and reported leg pain was negatively associated with walking speed. Multiple regression analysis showed that in men 44% of the variance in walking speed was accounted for by height, calf strength and the presence of health problems, and that in women 42% of the variance was accounted for by height, calf strength, step-score and the presence of leg pain limiting mobility. The significance of these findings to maintenance and improvement of walking speed in the elderly is discussed.
TL;DR: The annexins are a family of calcium-binding proteins which possesses four or eight homologous internal repeats which may be calcium-and phospholipid-binding domains and are likely to play important roles in cellular regulation.
TL;DR: The mortality experienced by a cohort of 653 patients with celiac disease in Edinburgh and the Lothian region has been analyzed and there was no deficit in deaths from ischemic heart disease or stroke and the mortality rate in those diagnosed in childhood as having Celiac disease was similar to the general population.
TL;DR: Postmortem brain samples from the frontal cortex, hippocampus, putamen, entorhinal region, and amygdala of schizophrenic patients and controls and schizophrenia showed increasedMK-801 binding levels, reaching significance in the putamen.
Abstract: [3H]MK-801 binding was used as a marker for the NMDA receptorion channel complex in postmortem brain samples from the frontal cortex, hippocampus, putamen, entorhinal region, and amygdala of schizophrenic patients and controls. In schizophrenia [3H]MK-801 binding levels were increased in all brain regions investigated reaching significance in the putamen.
TL;DR: The genetic data suggest that the Marsupial wolf was more closely related to other Australian marsupial carnivores than to those of South America, and represents an example of convergent morphological evolution to South American car-nivorous marsupials as well as to true wolves.
Abstract: THE phylogenetic affiliation of the extinct marsupial wolf (Thy-lacinus cynocephalus), which once was widespread in Australia, has been uncertain. On the basis of morphology, some systematists argue that the thylacine was most closely related to an extinct group of South American carnivorous marsupials, the borhyaenids1-3, whereas others consider it to be closer to Australian carnivorous marsupials4. Here we use direct sequencing by means of the polymerase chain reaction (PCR) to compare 219 bases of mitochondrial (mt) DNA from museum specimens of the marsupial wolf and representatives of six genera of extant marsupials. In agreement with the results of an antigenic study of albumin5, our genetic data suggest that the marsupial wolf was more closely related to other Australian marsupial carnivores than to those of South America. Thus, the marsupial wolf represents an example of convergent morphological evolution to South American car-nivorous marsupials as well as to true wolves.
TL;DR: In post-mortem putamen samples from 27 schizophrenics and 27 controls D2 receptors were measured by Scatchard analysis using3H-spiperone as a ligand, maximum number of binding sites (Bmax) and apparent dissociation constant (KD) were significantly increased only in patients in whom neuroleptic medication had been given within a three-month period before death.
Abstract: In post-mortem putamen samples from 27 schizophrenics and 27 controls D2 receptors were measured by Scatchard analysis using 3H-spiperone as a ligand. Maximum number of binding sites (Bmax) and apparent dissociation constant (KD) were significantly increased only in patients in whom neuroleptic medication had been given within a three-month period before death. When the neuroleptic medication had been withdrawn at least 3 month before death, there was a slight, but not significant, reduction in Bmax values and unchanged KD values. Withdrawal of neuroleptic drugs was followed by a normalization of the KD values within 2 weeks and a slower reduction of Bmax values. There were 6 schizophrenic patients with mainly positive schizophrenic symptoms and 17 patients with mainly negative symptoms; positive schizophrenic symptoms were not related to higher Bmax values. There was no difference in 3H-spiperone binding between patients with and without movement disorders (tardive dyskinesia or extrapyramidal symptoms).
TL;DR: When the improvements, or otherwise, in clinical condition were related to changes in plasma levels of dihomogammalinolenic and arachidonic acids, it was found that there was a positive correlation between an improvement in clinical score and a rise in the fatty acid levels.
Abstract: Gamma-linolenic acid in the form of a particular variety of evening primrose oil (Epogam) has been reported of value in the treatment of atopic eczema. Nine controlled trials of evening primrose oil were performed in eight centres. Four of the trials were parallel and five cross-over. Doctors and patients assessed the severity of eczema by scoring measures of inflammation, dryness, scaliness, pruritus and overall skin involvement. Individual symptom scores were combined to give a single global score at each assessment point. In the analysis of the parallel studies, both patient and doctor scores showed a highly significant improvement over baseline (P less than 0.0001) due to Epogam: for both scores the effect of Epogam was significantly better than placebo. Similar results were obtained on analysis of the cross-over trials, but in this case the difference between Epogam and placebo in the doctors' global score, although in favour of Epogam, failed to reach significance. The effects on itch were particularly striking. There was no placebo response to this symptom, whereas there was a substantial and highly significant response to Epogam (P less than 0.0001). When the improvements, or otherwise, in clinical condition were related to changes in plasma levels of dihomogammalinolenic and arachidoni acids, it was found that there was a positive correlation between an improvement in clinical score and a rise in the fatty acid levels.
TL;DR: A questionnaire developed by the International Union against Tuberculosis and Lung Disease to assess Bronchial symptoms has been tested for its ability to predict the bronchial response to histamine in adults aged 18-64 years living in two areas of southern England.
Abstract: A questionnaire developed by the International Union against Tuberculosis and Lung Disease (IUATLD) to assess bronchial symptoms has been tested for its ability to predict the bronchial response to histamine in adults aged 18-64 years living in two areas of southern England. A number of questions were found to be independently associated with increased reactivity in the first randomly selected half of the subjects. These symptoms included wheeze, waking at night with shortness of breath, tightness in the chest or shortness of breath when exposed to animals, dust or feathers and the non-specific symptom of persistent problems with breathing. A predictive score based on these symptoms was more sensitive and only slightly less specific than the question on wheeze alone in predicting the response to histamine in the second half of the subjects. Questions about asthma though more specific were considerably less sensitive than either. Symptoms did not differentiate between reactivity associated with positive skin tests and that associated with smoking.
TL;DR: The dopamine hypothesis still provides a valuable approach to the study of schizophrenia and its treatment by drugs, but measurements of dopamine metabolites in vivo, or of the transmitter and its receptors in postmortem brain tissue, do not provide unequivocal evidence of a hyperactivity of dopaminergic neurotransmission in the disease.
Abstract: The dopamine hypothesis still provides a valuable approach to the study of schizophrenia and its treatment by drugs. Although the neuroleptic drugs appear to act via an inhibition of dopamine receptors, measurements of dopamine metabolites in vivo, or of the transmitter and its receptors in post-mortem brain tissue, do not provide unequivocal evidence of a hyperactivity of dopaminergic neurotransmission in the disease. Nevertheless, increased dopamine function might be a consequence of a primary neuronal abnormality in another system. Recent imaging studies and neuropathological reports suggest that, in some patients, there may be a deficit and/or disturbance of neurons in certain temporal limbic regions, and this is supported by some neurochemical investigations, particularly of neuropeptide and amino-acid transmitter systems. A loss of such neurons could conceivably lead to a disinhibition of limbic dopamine neurons, providing the means whereby neuroleptic drug treatment might ameliorate the effects of a neuronal deficit in schizophrenia.
TL;DR: Adding broadband noise to the modulated stimulus increased the neuron's temporal response to low modulation frequencies, and the change in mean-rate response to modulated stimuli was qualitatively similar to the pure-tone RIF.
Abstract: Neuronal responses were recorded to pure and to sinusoidally amplitude‐modulated (AM) tones at the characteristic frequency (CF) in the central nucleus of the inferior colliculus of anesthetized guinea pigs. Temporal (synchronized) and mean‐rate measures were derived from period histograms locked to the stimulus modulation waveform to characterize the modulation response. For stimuli presented in quiet, the modulation gain at low frequencies of modulation (approx <50 Hz) was inversely proportional to the neuron’s mean firing rate in response to both the modulated stimulus and to a pure tone at an equivalent level. In 43% of units the mean discharge rates in response to the AM stimuli were greatest for those modulation frequencies that generated the largest temporal responses. These discharge‐rate maxima occurred at signal intensities corresponding to the steeply sloping part of the neuron’s pure‐tone rate‐intensity function (RIF). The change in mean‐rate response to modulated stimuli, as a function of intensity, was qualitatively similar to the pure‐tone RIF. Adding broadband noise to the modulated stimulus increased the neuron’s temporal response to low modulation frequencies. This increase in modulation gain was correlated with mean firing rate in response to the modulation but did not bear a simple relationship to the noise‐induced shift in the RIF measured for a pure tone.
TL;DR: Patients with Grade II NS HD may require more aggressive initial therapy if their survival is to be improved and the histopathologic subdivision of NS HD into Grade I and Grade II is easy to perform and provides essential prognostic information that is independent of stage.
Abstract: Nodular sclerosing (NS) Hodgkin's disease (HD) with extensive areas of lymphocyte depletion or with numerous anaplastic Hodgkin's cells, termed Grade II NS, is associated with a poor response to initial therapy, an increased relapse rate, and decreased survival when compared with other NS variants, termed Grade I NS. The histopathologic subdivision of NS HD into Grade I and Grade II is easy to perform and provides essential prognostic information that is independent of stage. Patients with Grade II NS HD may require more aggressive initial therapy if their survival is to be improved.
TL;DR: Neither the gastric emptying nor small intestine transit of the tablets was affected by their size, however, the nature of the meal consumed had a marked effect on gastrics emptying and the nature the meal also appeared to influence the transit through the ileocaecal sphincter.
TL;DR: The proximity of minimum night temperatures during September to December to the LT10 temperatures of red spruce shoots receiving large inputs of SO4 2- , NO3 - , NH4 + and H+ suggests that decreases in frost hardiness caused by intercepted cloud water containing large concentrations of these ions may play a significant part in the observed decline at mountain-top locations.
Abstract: SUMMARY
Seedlings of red spruce [Picea rubens Sarg. syn. P. rubra (Du Roi) Link] were exposed to mists containing equimolar (NH4, SO4 and HNO3 at pHs of 2.5, 2.7, 3.0, 35, 4.0 or 5.0. The mists were applied twice each week, amounting to 2 mm precipitation equivalent on each occasion, between July and December, to open-top chambers supplied with charcoal-filtered air.
Frost hardiness of shoots excised from seedlings was determined on 6 occasions starting on 21 September, and was found to be strongly influenced by acid mist treatments, seedlings subject to the most acidic mists being the least frost hardy. On 21 September when the first sample was taken the lethal temperature for killing 50% of shoots (LT50) was – 11 °C for the least acidic (pH 5.0) mist and – 7 °C for the most acidic (pH 2.5). By 19 October, the LT50s of pH 5.0 and pH 2.5 mists were –27 and –15 °C respectively. All intermediate treatments ranked according to treatment concentration, with the smaller concentrations causing lower LT.50 values.
The treatment at pH 30 provided S and N inputs to the seedlings similar to those experienced by red spruce at elevations of about 1000 m in the southern Appalachians. At pH 3.0, the frost hardiness LT10 during October was typically 8 °C higher than the pH 5.0 treatment, leading to a significant increase in the probability of frost damage at the LT10 level in an average October.
The proximity of minimum night temperatures during September to December to the LT10 temperatures of red spruce shoots receiving large inputs of SO42-, NO3-, NH4+ and H+ suggests that decreases in frost hardiness caused by intercepted cloud water containing large concentrations of these ions may play a significant part in the observed decline at mountain-top locations.
TL;DR: Two variability indices, standard deviation percent mean and amplitude percent mean, provided the greatest separation between subjects with both a diagnosis of asthma and wheeze in the last year and subjects with neither feature and also provided the highest intra-class correlation coefficients.
Abstract: Although serial peak expiratory flow (PEF) measurements are often used to assess the variability of airflow obstruction, the range of values to be expected in the general population has never been defined, nor is there any consensus as to how PEF variability should be expressed. We have compared PEF recordings made by 121 subjects selected at random from the population of a small town (Group A) and 221 subjects selected because of wheeze in the last year (Group B). Subjects were asked to record PEF every 2 h during waking hours for 7 days using a mini-Wright® peak flow meter. Seven Indices of PEF variability were derived for each subject and the range for each index determined. All indices showed a positively skewed distribution in the random sample. Two variability indices, standard deviation percent mean and amplitude percent mean, provided the greatest separation between subjects with both a diagnosis of asthma and wheeze in the last year and subjects with neither feature and also provided the highest ...
TL;DR: The effects of several variables on the gelation behavior of the chitosan/glutaraldehyde system have been studied in this article, showing that the cross-linking mechanism involves formation of Schiff's base structures rather than Michael-type adducts as previously postulated.
Abstract: The effects of several variables on the gelation behaviour of the chitosan/glutaraldehyde system have been studied. The rate of gelation is increased by increase in concentration of either chitosan or glutaraldehyde, or by an increase in temperature, and reduced by an increase in the concentration of acetic acid. Addition of a number of neutral electrolytes also causes an increase in the rate of gelation, the increase being larger the greater the activity coefficient of the electrolyte. UV/visible and NMR spectra of glutaraldehyde, acetaldehyde and crotonaldehyde, together with those of their 2,4-dinitrophenylhydrazine derivatives, indicate that only a very small proportion (<0,15%) of the aldehyde groups have undergone an aldol condensation reaction leading to α,β-unsaturated aldehyde groups. This, together with other evidence, suggests that the cross-linking mechanism involves formation of Schiff's base structures rather than Michael-type adducts as previously postulated.
TL;DR: Though doctors may now diagnose asthma more readily wheezing still remains an important cause of school absence and still seems to be undertreated.
Abstract: The prevalence of wheezing, 'asthma', treatment for 'asthma', and school absence as a result of wheezing in Nottingham was calculated from a questionnaire survey of parents of 4750 children in a random sample of primary schools. A response was achieved for 3805 (80%) children of whom 438 (11.5%) had had episodes of wheezing in the last year and 224 (5.9%) had been diagnosed as having asthma. Asthma treatment had been prescribed for 251 (6.6%) of all children, two thirds of all the children receiving drugs. Two hundred and sixty five (7%) children had lost time from school because of wheezing (median loss of seven days). Of the 64 children losing more than 10 days, 45 (70%) were not taking any drugs, or taking only beta agonists. The prevalence of wheezing found by this survey was comparable with that in similarly designed surveys, though the proportion of children diagnosed as having asthma was higher. Though doctors may now diagnose asthma more readily wheezing still remains an important cause of school absence and still seems to be undertreated.
TL;DR: The social geography of the two groups suggests that the high rates of schizophrenia and related psychoses that were previously reported cannot be explained simply by differences in area of residence at the time of presentation.
Abstract: Forty-two consecutively identified Afro-Caribbean patients with a first episode of psychosis were compared with a similar group of non-Caribbean patients. A number of differences emerged, although the same proportion of patients in each group had symptoms for 6 months or more prior to psychiatric contact. Afro-Caribbean patients showed greater delay in seeking help, more 'disturbance' later in the course of their illness and were more likely to be admitted compulsorily. The social geography of the two groups suggests that the high rates of schizophrenia and related psychoses that we previously reported cannot be explained simply by differences in area of residence at the time of presentation.
TL;DR: In this paper, the authors considered the behaviour of anisotropic materials produced by continuous reinforcement of a matrix with one or two families of relatively stiff fibres and showed how torsional tests on thin plate specimens can be used to directly determine the transverse and longitudinal shear moduli for elastic, viscoelastic and elastic-plastic behaviours.
TL;DR: Bacterial contaminants of micropropagated plant cultures were isolated and characterized with standard bacteriological tests and appropriate API strips and 90% were identified as Bacillus, Enterobacter, Micrococcus, Staphylococcus, Pseudomonas or Lactobacillus species.
Abstract: Bacterial contaminants of micropropagated plant cultures were isolated and characterized with standard bacteriological tests and appropriate API strips. Results obtained were analysed by the API identification software. Of 198 bacterial strains isolated from nine plant species, 90% were identified as Bacillus, Enterobacter, Micrococcus, Staphylococcus, Pseudomonas or Lactobacillus species. Possible sources of contamination are discussed.