Showing papers by "Medical Research Council published in 1977"
TL;DR: The original assay of neurotoxic esterase (NTE) in brains taken from dosed hens enables potential neurotoxicity of organophosphate pesticides, plasticers, etc. to be assessed.
Abstract: The assay of neurotoxic esterase (NTE) in brains taken from dosed hens enables potential neurotoxicity of organophosphate pesticides, plasticers, etc. to be assessed. The original assay [Johnson, M. K. Biochem. J. 114, 711–717 (1969)] has been simplified to eliminate centrifugation and transfer steps and both the selectivity and the sensitivity have been increased. The procedures necessary to obtain stable reagent stocks are described.
381 citations
TL;DR: In a prospective trial in 72 postmenopausal women to compare the effects on bone loss of no treatment, treatment with oestrogen, and treatment with calcium the women were followed up for at least two years and examined densitometristically and morphometrically.
Abstract: In a prospective trial in 72 postmenopausal women to compare the effects on bone loss of no treatment, treatment with oestrogen, and treatment with calcium the women were followed up for at least two years and examined densitometrically and morphometrically. Women in the untreated control group continued to lose bone during the two years, whereas the oestrogen-treated group lost none. Loss in the calcium-treated group was intermediate. Oestrogen appeared to inhibit endosteal bone resorption and may have stimulated subperiosteal bone apposition.
346 citations
TL;DR: Host-range mutants of adenovirus type 5 have been selected on human embryo kidney cells transformed by sheared adeno 5 DNA and these mutants grow well on 293 cells, but are restricted on HeLa cells.
317 citations
TL;DR: Evidence is presented to show that pairs of click stimuli, 5 ms apart, presented at a fast stimulus rate, stress the auditory system in normal subjects and abnormalities of component V in patients became more marked and the proportion of abnormalities detected was increased.
Abstract: Fifteen components of the auditory evoked potential can be recorded within 300 ms of a click stimulus and these can be classified by latency in early (0-8 ms), middle (8-60 ms) and late (greater than 60 ms) components. Follwing a click stimulus of high intensity these components have been studied in 45 normal subjects and in 88 patients with definite multiple sclerosis. Component V, thought to arise from brain-stem structures, was the most consistently abnormal in patients and there was a correlation between the abnormalities and clinical evidence of a brain-stem lesion. Thus in 79 per cent of patients with definite evidence of a brain-stem lesion and in 51 per cent of those without clinical signs related to the brain-stem, component V was abnormal. Abnormalities were also detected for components Pa, Nb and P1 of the middle components, and in 12 per cent of these the early components were normal. The late components were normal in all but 3 patients. Evidence is presented to show that pairs of click stimuli, 5 ms apart, presented at a fast stimulus rate, stress the auditory system in normal subjects. Using this technique abnormalities of component V in patients became more marked and the proportion of abnormalities detected was increased. The contribution of the reflex muscle responses to the click to the middle components of the auditory evoked potential has also been studied. It is concluded that components Pa, Nb and P1 are independent of these reflexes.
298 citations
TL;DR: It is suggested that L-deprenil may act through inhibition of brain M.A.O. as well as by a psychostimulant effect similar to that of amphetamine which occurs through the release of dopamine to make more dopamine available at dopamine receptor sites.
291 citations
TL;DR: A chronic relapsing form of experimental allergic encephalomyelitis was induced by single sensitization of immature strain 13 and Hartley guinea pigs and opened new avenues for the study of immunological mechanisms governing remissions and exacerbations in multiple sclerosis.
Abstract: A chronic relapsing form of experimental allergic encephalomyelitis was induced by single sensitization of immature strain 13 and Hartley guinea pigs. Clinically, the disease was characterized by remissions and relapses. Recent and old demyelinating plaques, which are the two characteristic features of multiple sclerosis lesions, were also present. The model described opens new avenues for the study of immunological mechanisms governing remissions and exacerbations in multiple sclerosis and offers new opportunities for evaluating the efficacy of drugs for its treatment.
270 citations
TL;DR: Hyperviscosity and reduced erythrocyte deformability may well be important and potentially treatable factors in the aetiology or progression of microcirculatory disease is diabetes.
242 citations
TL;DR: The present data clearly show that estrogens and thyroid hormones can affect TSH andPRL secretion, the effect of estrogens being predominantly on PRL secretion while thyroid hormone affects mainly TSH.
Abstract: The effect of estradiol and thyroid hormone treatment on pituitary TRH binding and TSH and PRL responses to the neurohormone was studied. A significant increase in the number of pituitary TRH binding sites was observed between 2 and 4 days after daily administration of estradiol benzoate with a plateau at 300% of control being reached at 7 days. Plasma PRL levels showed a similar early pattern of response. In animals rendered hypothyroid by a 2-month treatment with propylthiouracil or 1 month after surgical thyroidectomy, the level of pituitary TRH receptors was increased approximately 2-fold, this elevation being completely reversed by treatment with thyroid hormone. Estradiol-17beta administered with L-thyroxine partially reversed the inhibitory effect of thyroid hormone on TRH receptor levels in hypothyroid animals. The antagonism between estrogens and thyroid hormone is also apparent on the TSH response to TRH since estrogen administration can reverse the marked inhibition by thyroxine of the TSH response to TRH either partially or completely in intact and hypothyroid animals, respectively. The PRL response to TRH is 55 and 40% inhibited in hypothyroid and intact rats, respectively, by thyroid hormone when combined with estrogen treatment. The present data clearly show that estrogens and thyroid hormones can affect TSH and PRL secretion, the effect of estrogens being predominantly on PRL secretion while thyroid hormone affects mainly TSH. The close correlation observed between the level of TRH receptors and PRL and TSH responses to TRH suggests that estrogens and, to a lesser extent, thyroid hormones, exert their action by modulation of the level of receptors for the neurohormone in both thyrotrophs and mammotrophs.
222 citations
207 citations
TL;DR: To evaluate the predictive value of blood pressures for future levels, longitudinal measurements were analyzed among Welsh subjects from age 5 to 74 at entry and the findings are very similar for each of the two regions studied.
Abstract: To evaluate the predictive value of blood pressures for future levels, longitudinal measurements were analyzed among Welsh subjects from age 5 to 74 at entry. The measurements were taken on 863 individuals from the Vale of Glamorgan in 1956, 1960, 1964, and 1971 and on 734 individuals from the Rhondda Fach in 1954, 1958, 1964, and 1971. The tracking correlation, defined as the correlation between blood pressure readings on the same person taken at two different times, is used as a descriptive measure of the magnitude of the association. The tracking correlations range from 0.25 to 0.6-0.7 with most of the increases occurring before age 20. The tracking correlation depends on initial age, sex, and time interval between measurements. The age-specific tracking correlations decrease as time interval between measurements increases. For a given time interval, the age-specific correlations are slightly higher for females than for males. These findings are very similar for each of the two regions studied.
205 citations
TL;DR: It was concluded that the gametocytes of P. falciparum are both long-lived and show persistent infectivity to mosquitoes, which can stimulate antibody production but the immune response appears to play no part in their elimination.
Abstract: The longevity and infectivity of isolated populations of Plasmodium falciparum gametocytes were studied. Following chloroquine treatment gametocyte numbers fell with a constant rate of loss over a period of 16–24days; the populations had a half-life of 2·4 days. The sex ratio stayed constant throughout at 4 female:1 male. The ability of the microgametocytes to exflagellate and the infectivity of the population to mosquitoes persisted for 3 weeks. Antibodies to the gametocytes were detected but not in every patient studied. It was concluded that the gametocytes of P. falciparum are both long-lived and show persistent infectivity to mosquitoes. They can stimulatae antibody production but the immune response appears to play no part in their elimination, which probably takes place in the spleen as a part of the normal process of removing old, damaged and malformed red cells.
TL;DR: There is no consistent evidence that giving rifampicin with isoniazid in the initial treatment of tuberculosis increases the risk of hepatitis; in particular, transient abnormalities in the results of tests of liver function during the early weeks of treatment do not imply serious toxicity.
TL;DR: This chapter describes the methods for nuclear transplantation in amphibia to test the genetic content of somatic cells and to analyze interactions between nucleus and cytoplasm.
Abstract: Publisher Summary This chapter describes the methods for nuclear transplantation in amphibia. The reasons for developing the technique of nuclear transplantation are to test the genetic content of somatic cells and to analyze interactions between nucleus and cytoplasm. The chapter discusses potential applications of this technique. Among multicellular organisms, the large size and ready availability of the eggs and oocytes of amphibia give them great advantages for nuclear transplantation over those of other animals. The techniques are applicable to eggs and oocytes of Xenopus laevis . Minor differences in technique apply to eggs of Ram pipiens . Hormone injection causes fully grown oocytes to be released from the ovary, passed down the oviduct where they are surrounded by jelly, and released into the surrounding water. Eggs, unlike oocytes, can be fertilized and can commence development. The most useful applications of nuclear transplantation methods for investigating the function of chromosomal proteins involve multiple nuclear transfers and the injection of purified genes or chromosomal proteins.
TL;DR: The induction of inactivation and mutation to thioguanine-resistance of two types of cultured mammalian cells, V79 Chinese hamster and HF19 human diploid, was studied after irradiation with aluminium K characteristic ultrasoft X-rays, helium ion track intersections of different LET, 42 MeV d-Be neutrons, and hard X- or gamma-rays.
Abstract: SummaryMicrodosimetric distributions for aluminium K characteristic ultrasoft X-rays and 4He ion track intersections are calculated and used to analyse recent biological results obtained with these radiations. Results on inactivation and mutation-induction to thioguanine resistance of both V79 Chinese hamster cells and HF19 human diploid fibroblasts in vitro are analysed in terms of the Kellerer-Rossi ‘theory of dual radiation action’. The small quantum energy of the aluminium X-ray photons and the very short length of the secondary electrons which they produce highlight the inadequacy of the model. It is shown that the model predicts r.b.e. values in conflict with those observed unless an additional variable is introduced, but that the introduction of such a variable creates mathematical inconsistencies. The experimental evidence is contrary to the conventional usage and basis of the model.
TL;DR: Pure cultures of a very toxic strain of Fusarium moniliforme Sheldon var.
TL;DR: The aim of this work is to establish a baseline diet for laboratory animals of similar, stable and repeatable performance and to provide a guide for the development of suitable diets for future generations of animals.
Abstract: Preface Demands by experimental workers for standard materials, in this case for animals of similar, stable and repeatable performance, have resulted in an increasing sophistication in laboratory animal husbandry. Microbiological and genetic definition of animals has improved reproducibility of results, but variation is still introduced or enhanced by other factors, one of the most common of which is the diet. With this in mind the Medical Research Council Laboratory Animals Centre set up in 1974 a Laboratory Animals Diets Advisory Committee. The
TL;DR: Bilateral surgical neodecortication did not prevent perfect retention of a Pavlovian nictitating membrane response in rabbits if the original learning took place in the normal state but did abolish the acquired responses if the animals were hemidecorticate at the time of original learning.
TL;DR: The mutagenic activities of the positive control mutagens ultraviolet light, potassium chromate, ethyl methanesulphonate and benzo(a)pyrene were detected in the experiments, however, no Mutagenic activity was found to be associted with any of the asbestos and glass fibres tested over a wide range of concentrations.
Abstract: Asbestos fibres are carcinogenic in man and experimental animals but fine glass fibres are known, at present, only to be carcinogenic in experimental animals. Asbestos and glass fibres have been studied in mutation tests using auxotrophic strains of Escherichia coli and Salmonella typhimurium . The mutagenic activities of the positive control mutagens ultraviolet light, potassium chromate, ethyl methanesulphonate and benzo(a)pyrene were detected in the experiments. However, no mutagenic activity was found to be associated with any of the asbestos and glass fibres tested over a wide range of concentrations. The implications of these findings for the mode of action of asbestos and glass fibres as carcinogens are discussed.
TL;DR: It is concluded that liposomes of appropriate composition may be sufficiently benign to use as carriers of therapeutic agents into the CNS.
TL;DR: Although there is no single “best” presentation format, and although the research literature is in many places incomplete, nevertheless there are a number of studies demonstrating the advantages of particular presentation formats in specific circumstances.
Abstract: This paper reviews research investigations into various aspects of the presentation of technical information. It considers the objectives of different readers who may be consulting the information as a reference work or who may need to assimilate the information in its entirety. Ways of using headings, summaries and questions to achieve these differing objectives are discussed. The review also considers the usefulness of alternatives to prose, such as flow charts, tabulation schemes and graphic presentations. It is concluded that although there is no single “best” presentation format, and although the research literature is in many places incomplete, nevertheless there are a number of studies demonstrating the advantages of particular presentation formats in specific circumstances. The results of these studies need to be given due weighting where decisions are taken about the appropriate way of presenting any technical information.
TL;DR: Pectin and perhaps other unabsorbable polysaccharides are likely to prove useful in the treatment of abnormal carbohydrate absorption after gastric surgery.
TL;DR: The findings suggest that conduction is abnormal in at least some surviving nerve fibres in patients who developed a peripheral neuropathy 10 days to 3 weeks after ingestion of a single dose of arsenic.
TL;DR: The vascular permeability in the nervous system to Evans blue-albumin and horseradish peroxidase was studied in chronic relapsing EAE in strain 13 and Hartley guinea pigs and showed an increased permeability to the protein tracers.
Abstract: The vascular permeability in the nervous system to Evans blue-albumin and horseradish peroxidase was studied in chronic relapsing EAE in strain 13 and Hartley guinea pigs. The disease was induced by single sensitization of immature animals and was characterized clinically by remissions and relapses. Recent and old demyelinating plaques in the spinal cord were present. These showed an increased permeability to the protein tracers. The blood-brain barrier in these plaques are therefore disturbed and also in this respect the condition is similar to the multiple sclerosis lesions.
TL;DR: Though the presented reading ages are with reference to hearing norms, other criteria for assessing the reading performance of deaf children are discussed.
Abstract: Summary Almost every child aged 15–16 1/2 years being educated in schools for the deaf and partially hearing in England and Wales, was given Brimer's Wide-Span Reading Test which assesses prose comprehension After excluding certain categories of children, results were available for 355 children With degree of hearing loss as the main independent variable, results are presented in terms of mean and median reading age, and in reading age percentile form Reading is significantly affected by degree of deafness and by non-verbal intelligence Though the presented reading ages are with reference to hearing norms, other criteria for assessing the reading performance of deaf children are discussed
TL;DR: The effect of various hormone treatments was investigated on the growth and hormone receptor levels of hormone-dependent (those which regressed after ovariectomy) dimethylbenz- (a)anthracene (DMBA)-induced mammary tumors in the rat.
Abstract: The effect of various hormone treatments was investigated on the growth and hormone receptor levels of hormone-dependent (those which regressed after ovariectomy) dimethylbenz- (a)anthracene (DMBA)-induced mammary tumors in the rat. Hormone binding measured in die tumors which remained 5½ weeks after ovariectomy was low for estradiol-17β (E2) (0.6 ± 0.2 pmol/g tissue), R 5020 (0.9 ± 0.4 pmol/g tissue) and prolactin (PRL) (0.9 ± 0.4% of specific binding). In non-castrated animals, binding values were 2.9 ± 0.4 pmol/g tissue, 13.7 ± 2.0 pmol/g tissue and 3.2 ± 0.3% for E2, R 5020 and PRL, respectively. Administration of progesterone (P) alone (0.5 mg/day) for three weeks to castrated animals had no effect on tumor size or hormone binding. Treatment with E2 (0.5 μg/day) for the same period of time increased tumor size and hormone binding: E2, 3.0 ± 0.7 pmol/g tissue; R 5020, 14.8 ± 3.3 pmol/g tissue; PRL, 2.4 ± 0.6%. At a daily dose of 2 mg, PRL alone increased tumor size slightly while honnone binding remai...
TL;DR: The finding that exercise induces a decrease in TG despite increased food intake indicates that the TG lowering effect of exercise is not mediated by a negative caloric balance.
TL;DR: Eight cases of fungal infection are described in which an arthrosporic hyphomycete has been isolated from patients of Jamaican and West African origin and the fungus is described as a new species of Scytalidium (S. hyalinum).
Abstract: Eight cases of fungal infection are described in which an arthrosporic hyphomycete has been isolated from patients of Jamaican and West African origin. In most cases the organism was the only one isolated and in one case it was isolated 3 times over a 5 month period. The fungus is described as a new species of Scytalidium (S. hyalinum).