Showing papers by "Cardiff University published in 1983"

Ethnography: Principles and Practice

Abstract: Acknowledgements Preface 1. What is ethnography? 2. Research design: problems, cases, and samples 3. Access 4. Field relations 5. Insider Accounts: listening and asking questions 6. Documents 7. Recording and organizing data 8. The process of Analysis 9. Writing Ethnography 10. Ethics References Index

Estimating Parameters in Continuous Univariate Distributions with a Shifted Origin

Abstract: SUMMARY A general method of estimating parameters in continuous univariate distributions is proposed. It is especially suited to cases where one of the parameters is an unknown shifted origin. This occurs, for example, in the three-parameter lognormal, gamma and Weibull models. For such distributions it is known that maximum likelihood (ML) estimation can break down because the likelihood is unbounded and this can lead to inconsistent estimators. Properties of the proposed method are described. In particular it is shown to give consistent estimators with asymptotic efficiency equal to ML estimators when these exist. Moreover it gives consistent, asymptotically efficient estimators in situations where ML fails. Examples are given including numerical ones showing the advantages of the method.

Linkage analysis of two cloned DNA sequences flanking the Duchenne muscular dystrophy locus on the short arm of the human X chromosome

Abstract: The inheritance of two restriction fragment length polymorphisms (RFLPs) on the short arm of the human X chromosome has been studied relative to Duchenne muscular dystrophy. This provides a partial genetic map of the short arm of the human X chromosome between Xp110 and Xp223. The data were derived from the segregation between a RFLP located at Xp21-Xp223, the DMD locus, and a RFLP located at Xp110-Xp113. The genetic distance from Xp110 to Xp223 was found to be approximately 40 centimorgans (cM). This provides experimental confirmation that 1cM corresponds to approximately 1,000 kilobase pairs of DNA for this region of the human X chromosome. Our data confirm that the DMD mutation lies between Xp223 and Xp110. The availability of flanking probes surrounding the DMD locus will assist in the ordering of further DNA sequences relative to the mutation.

A simple post-embedding system for the rapid demonstration of tissue antigens under the electron microscope.

Abstract: A simple and versatile technique for the preparation of ultra-thin sections, which can be stained immunohistochemically directly on electron microscope grids, is presented. An anti-hapten immunoperoxidase procedure has been adapted for use on tissue fixed in a purified monomeric glutaraldehyde--picric acid mixture, and embedded in 'L R White', a recently formulated plastic resin. This plastic tolerates the use of partial dehydration of tissue, resulting in higher antigenic yields. In addition, no etching of ultra-thin sections is necessary, and the whole immunostaining procedure can be completed in less than 2 h. A comparison of commonly used fixatives is discussed. High-resolution micrographs showing general staining (uranyl acetate--lead citrate) of rat pancreas, and immunostaining of insulin and TSH in storage granules in perfusion-fixed rat tissue and of lambda-chain immunoreactive cells in immersion-fixed human tonsil are included as examples.

Age at any birth and breast cancer risk

Abstract: In an effort to assess the relative importance of age at first birth, age at subsequent births, and total parity to the occurrence of breast cancer, reproductive data from 4,225 women with breast cancer and 12,307 hospitalized women without breast cancer were analyzed by a multiple logistic regression model. Age at first birth was confirmed to be the most important reproductive risk indicator; it was associated with a 3.5 % increase of relative risk for every year of increase in age at first birth (the 95 % confidence interval of this estimate was 2.3 to 4.7 % increase per year). However, age at any birth after the first was also an independent and statistically significant risk indicator; it was associated with a 0.9% increase of relative risk for every year of increase in age at any (and every) birth (the 95 % confidence interval of this estimate was 0.4 to 1.5 % increase per year). There is evidence that the age of approximately 35 years represents for every birth a critical point; before this age any full-term pregnancy confers some degree of protection; after this age any full-term pregnancy appears to be associated with increase in breast cancer risk. The effect of parity is determined by the age of occurrence of the component pregnancies. While most pregnancies occur under the age of 35, the distribution varies from population to population, and this may account for the differences between populations in whether or not a protective effect is seen for births after the first, and if it is seen, its extent.

Effect of toothpaste rinses compared with chlorhexidine on plaque formation during a 4-day period.

Abstract: Evidence suggests that brushing with a toothpaste may slow plaque reformation over 24 h. This study measured the effect of toothpaste alone on plaque regrowth over a 96 h period and compared the effect with water and the known antiplaque agent chlorhexidine. At 9 a.m. at the beginning of 7,4-day no oral hygiene periods, 10 volunteers were scaled and polished. Al 5 p.m. subjects brushed their own teeth with water until plaque free. Each subject rinsed for I min with 10 ml of a randomly allocated rinse. Rinsing was repeated at 10 a.m. and 10 p.m. on subsequent days. The rinses were water, chlorhexidine 0.2% or 3 g/10 ml slurries of toothpastes containing (1) monofluorophosphate(MFP), (2) monofluorophosphate + sodium fluoride (MFP+NaF) (3) monofluorophosphate + zinc citrate (MFP+ZCT) (4) stannous fluoride (SnF2) (5) sodium fluoride (NaF). At 16, 24, 48 and 72 h plaque on the buccal surface of the upper and lower premolars, canines and incisors was scored by the Gingival Margin Plaque Index (GMPI) and gram films of plaque samples made. At 96 h plaque was recorded diagraromatically and areas of coverage measured visually (Debris Index) and by planimetry. Progressive plaque formation to a Gingival Margin Plaque Index of 100% at 72 h was observed for toothpaste and water rinses. For chlorhexidine the Gingival Margin Plaque Index at 72 h was 6%, At 96 h plaque areas were significantly less with toothpaste rinses compared with water. Chlorhexidine very significantly reduced plaque areas compared with toothpaste and water. The bacteriological assessment of smears revealed essentially similar plaque development during toothpaste and water rinses and was consistent with previous reports. However, with chlorhexidine the densities of organisms in the smears were greatly reduced. It was concluded that the small effect of toothpaste rinses on plaque accumulation compared with chlorhexidine would not alone represent a true antiplaque effect resulting in therapeutic benefit.

Dentine hypersensitivity--a review. Clinical and in vitro evaluation of treatment agents.

Abstract: A large number of compounds have been employed in the management of dentine hypersensitivity. The symptomatic nature of the condition and its variability poses many problems to any evaluation of effect. Several semi-quantitative methods of response have been used; however, at this time it is uncertain what advantages they hold over the patients' subjective assessment of improvement. A review of the clinical studies reveals that a positive result for every agent tested to date may be found. Nevertheless considerable placebo responses have been obtained and equivocal results are occasionally reported. The fluorides and metal salts, particularly of strontium, have been most studied when used either in solution or delivered in toothpaste formulations. For these compounds the literature contains considerable information concerning the reaction with dental hard tissues which can be extrapolated into hypotheses for the modes of action in relieving dentine hypersensitivity. Moreover, some in vitro studies provide useful information concerning the effects of certain compounds on dentine, and are consistent with the clinical data. Unfortunately, contradictory findings and anomalies between clinical and in vitro effects still prevent the development of a sound clinical basis for the treatment of the condition. Moreover, there is a need to recognise those factors which predispose to dentine exposure, if the prevention of the occurrence or re-occurrence of hypersensitivity is to be achieved.

The Effects of Camphor, Eucalyptus and Menthol Vapour on Nasal Resistance to Airflow and Nasal Sensation

Abstract: The effects of five minutes exposure to camphor, eucalypths or menthol vapour on nasal resistance to airflow and nasal sensation of airflow were compared with the effects of exercise on the nose. I...

The effect of menthol on nasal resistance to air flow.

Abstract: Total nasal resistance to airflow was measured in thirty-one subjects before and after five minutes' exposure to menthol vapour. Menthol inhalation had no consistent effect on nasal resistance but the majority of subjects reported an increased sensation of nasal airflow and a cooling effect of menthol. The results indicate that menthol stimulates cold receptors in the nasal mucosa to create an increased sensation of airflow. No evidence was found in support of any nasal decongestant action for menthol.

Dopamine Receptors on Intact Anterior Pituitary Cells in Culture: Functional Association with the Inhibition of Prolactin and Thyrotropin

Abstract: Dopamine (DA) and the dopaminergic agonists bromocriptine and apomorphine inhibit the secretion of TSH as well as that of PRL by rat anterior pituitary (AP) cells in monolayer culture. The order of potency of the drugs is the same for the inhibition of both hormones: bromocriptine ED50 = 0.006 nM against PRL and 0.017 nM against TSH; apomorphine ED50 = 2.9 and 4.8 nM, respectively, and DA, ED50 = 30 and 370 nM, respectively. The dopaminergic antagonists domperidone (DOM) and metoclopramide prevent the inhibition of TSH and PRL by 10-6 M DA (IC50 = 0.012 and 0.32 nM for metoclopramide against PRL and TSH, respectively; similarly, IC50 = 0.01 and 0.61 nM for DOM). The action of butaclamol is shown to be stereospecific, in that the (+) isomer is 1000-fold more potent in reversing the inhibition of both TSH and PRL by 10-6 M DA than the (-) isomer [IC50 = 1.1 and 7200 nM for the (+) and (-) isomers against PRL; similarly, 6.3 and 2600 nM against TSH]. The use of radioligand-binding techniques with tritiated D...

Glycosylated Serum Albumin: An Intermediate Index of Diabetic Control

Abstract: Glycosylated hemoglobin (HbA1) is widely used as an index of glycemic control in diabetic patients. However, due to the long survival time of erythrocytes (120 days), it remains elevated for several weeks after improved control. Other plasma proteins are similarly glycosylated, and as glycosylated serum albumin (GSA) has a shorter half-life (20 days), it should detect glycemic changes earlier. Fasting blood glucose (FBG), GSA, and HbA1 were measured weekly in newly diagnosed diabetic patients ( N = 12) for 8 wk after beginning treatment. After 4 wk, a similar fall in FBG and GSA levels, i.e., 72% and 58% respectively, was observed. In contrast, HbA1 fell significantly less ( P < 0.01), by only 39% of its initial value. By 8 wk there was no significant difference between the percentage reduction in the three indices of control. Therefore, GSA provides the clinician with earlier objective evidence of the metabolic response to therapeutic intervention and can be regarded as an intermediate index of diabetic control.

Effect of Norethisterone on Seizures Associated with Menstruation

Abstract: Summary: The effect of high and low doses of norethisterone on seizure frequency was studied in nine epileptic patients, aged 20–30 years. All patients satisfied the defined criteria of having catamenial exacerbation. The study was double blind, placebo controlled, and randomised. Each patient was followed through four menstrual cycles with each drug dose and also with placebo. The results of this study suggest that norethisterone is not effective in the control of seizures associated with the menstrual period. RESUMEN El efecto de dosis altas o bajas de noretisterona sobre la frecuencia de ataques ha sido estudiado en epilepticos de 20–30 anos de edad. Todos los pacientes cum-plfan los criterios de presentar exacerbaciones catameniales. El estudio fue doble ciego, usando placebo y randomizado. Cada paciente fue estudiado durante 4 ciclos menstruales con cada dosis de medicacion y tambien con placebo. Los resultados de este estudio sugieren que la noretisterona no es eficaz en el control de los ataques asociados al ciclo menstrual. ZUSAMMENFASSUNG Die Wirkung hoher und nie driger Dosen von No-rethisteron auf die Anfallsfrequenz wurde bei 9 epi-leptischen Patienten zwischen 20 und 30 Jahren un-tersucht. Alle Patienten genugten den definierten Kriterien einer Exacerbation der Epilepsie wahrend der Menstruation. Diese Studie wurde als Doppeltblind-, Placebo-kontrollierter Versuch, randomisiert, durch-gefuhrt. Jede Patientin wurde wahrend 4 Menstrua-tionszyklen unter jeder Dosis des Medikaments und unter Placebo untersucht. Die Ergebnisse dieser Stu-dien lassen vermuten, das Norethisteron keine Wirkung auf die Anfallskontrolle wahrend des Menstrua-tionszyklus besitzt.

Juvenile hyaline fibromatosis.

Abstract: SUMMARY A 4-year-old boy with juvenile hyaline fibromatosis (systemic hyalinosis) is described. The clinical features, pathology and prognosis of this condition are discussed.

Parametric studies of tinnitus masking and residual inhibition.

Abstract: A study was made of the relation between tinnitus masker composition (frequency, bandwidth, intensity duration) and the time course and magnitude of residual inhibition (RI). RI was determined by methods of (a) loudness estimation - where the subject varied the pointer position on a loudness scale (b) loudness balance - where the tinnitus loudness was maintained in loudness balance in the period following masking with a tone of variable intensity presented to the opposite ear. In addition, sensitivity change (temporary threshold shift, TTS) in the tinnitus and masker frequency regions was measured by determining tone thresholds (using a tracking technique) before and after masker presentation. The key findings were as follows: (I) RI depends on masker centre frequency. The frequency producing maximal RI is usually lower than the tinnitus frequency (as determined by pitch matching). (2) In some subjects only narrow-band noise produces RI. (3) RI is proportional to the masker intensity provided the tinnitus is completely masked; little or no RI is produced by a partial masker. (4) For the masker durations used (in the range 10 s to 10 min) RI duration is linearly related to the logarithm of masker duration. (5) A second masker presentation during RI does not potentiate RI. (6) Contralateral masking did not produce RI. (7) maskers producing RI also produce TTS around the tinnitus frequency. (8) The TTS magnitude and the time course of TTS appear to be related to RI.

The visibility of galaxies as a function of central surface brightness

Abstract: On demontre que le volume dans lequel une galaxie sera visible est une fonction de la brillance de surface au centre de la galaxie aussi bien que de sa magnitude absolue. Il doit etre tenu compte de cet effet de selection

The present status of chelating agents in medicine.

Abstract: Publisher Summary This chapter describes methods of treating heavy metal intoxication. The chapter discusses the common ground between different approaches to chelation therapy rather than to be over-concerned with the details of individual metal toxicity and its treatment. The chapter also discusses some other medical applications of chelating agents that have become prominent in the past few years. Present treatment of acute iron and lead poisoning is usually gratifyingly successful and a few new agents have been found which appear to have considerable potential. Special attention must be devoted to this interrelationship if metal complexation in areas of medicine other than chelation therapy is to be effectively exploited. The therapeutic potential of chelating agents as a class of compounds is thus, probably, unparalleled. However, all depends on the future design of agents with sufficient chemical and physical selectivity to achieve very specific biochemical objectives.

The presence of oxygen in rumen liquor and its effects on methanogenesis

Abstract: In situ measurement of O2 in the rumen liquor of cows, sheep and goats using a membrane-covered O2 electrode revealed the presence of up to 1630 nmol/l O2; O2 became undetectable immediately after feeding of animals. The effects of O2 on H2 production and methanogenesis in samples of rumen liquor were investigated using a mass spectrometer fitted with a membrane inlet system. Methanogenesis was totally and irreversibly inhibited after short term exposure (about 10 min) to 5 KPa (0·05 atm) O2; H2 production was unaffected. Glucose additions produced rapid transient increases in H2 levels and increased O2 uptake.