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J Hughes

Publications and source records attributed to J Hughes.

At least 343 records · Page 19Linked to original sources
PubMed1992

The Consortium to Establish a Registry for Alzheimer's Disease (CERAD). Part III. Reliability of a standardized MRI evaluation of Alzheimer's disease.

The Consortium to Establish a Registry for Alzheimer's Disease (CERAD) has developed procedures for standardized imaging and reporting of magnetic resonance (MR) findings in Alzheimer's disease (AD) for use by neuroradiologists in multiple medical centers using a variety of MR equipment and field strengths. After initial pretesting, we revised the protocol, expanded the summary rating scale to seven points, and added more illustrations. Fourteen participating neuroradiologists evaluated 28 MR scans of elderly patients, giving us the basis for judging interrater agreement. We obtained acceptable intraclass correlations (greater than 0.79) for rating the size of the lateral and third ventricles and the temporal horn. Less satisfactory intraclass correlations occurred when rating other areas, including (1) global atrophy of the brain (0.70); (2) dilatation of the sulci of the temporal lobe (0.66); (3) frequency, location, and severity of white matter lesions (0.77); (4) sylvian fissure enlargement (0.70); and (5) cerebral sulcal dilatation (0.64). We also saw considerable variation in the reporting of cortical and lacunar infarcts. Despite careful design of the rating methodology and readings by experienced neuroradiologists, we did not find satisfactory interrater agreement for interpreting MR findings in elderly subjects. These findings may explain the difficulties encountered in applying similar subjective rating techniques that meet with success at one institution to multicenter studies. More objective and reproducible procedures are needed for interpretation of neuroimaging findings of AD in multicenter studies.

Alzheimer Disease↗
PubMed1992

Apparent duration and spatial structure.

In three experiments, we investigated the relative perceived duration of a full bandwidth image and a set of high- and lowpass filtered images of a scene, briefly presented on a visual display unit. In Experiment 1, the various images were compared with each other, using a paired comparison method. All images were presented for 40 msec, and observers were asked to judge which of each pair of images had the longest duration. The results showed that images containing a wide spatial frequency bandwidth were judged to be of longer duration than were images of a narrower bandwidth, regardless of whether the latter were high- or lowpass filtered. In Experiment 2, a 40-msec presentation of each of the images was compared with a presentation of a probe that was 20, 40, 60, or 80 msec in duration. Observers again judged which of each pair of images had the longest duration. The results were very similar to those of Experiment 1, with wide bandwidth images being judged to be of longer duration than were narrow bandwidth images. In Experiment 3, instead of comparing the various filtered versions of the image with each other, we attempted to obtain a direct measure of perceived duration by comparing a flashing LED to a 40-msec flash of a subset of the images used in the previous experiments. The observers' task was to adjust the duration of the LED flash to match the perceived duration of each image.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Neuropeptides. Function and clinical applications.

Neuropeptides are the most abundant chemical messengers in the brain and their major role seems to be the modulation of amine and amino acid neurotransmission. This appears to be achieved at many sites by the co-release of peptide with the primary transmitter. The presynaptic biochemistry and physiology of neuropeptides ensure that neuromodulation is highly plastic with almost infinite adaptive potential. The recent development of novel drugs (termed peptoids) that mimic or block neuropeptide function have opened up new clinical approaches to a number of conditions. Thus high efficacy kappa opioid-receptor agonists such as CI-977 (enadoline) have potential for the treatment of pain and stroke whilst the development of highly selective and bioavailable cholecystokinin B (CCK-B) antagonists such as CI-988 ([R-(R*,R*)]-4-[[2-[[3-(1H-indol-3-yl)-2-methyl-1-ox6-2- [[tricyclo[3.3.1.1.3.1]dec-2-yloxy)carbonyl]amino]propyl]ami no]-1-phenethyl]amino-4-oxobutanoic acid) have offered new insights into the mechanisms underlying and the treatment of anxiety disorders and drug abuse. In general it appears that peptoids may offer a greater selectivity of drug action when compared to amino acid/amine based compounds. Peptoid antagonists appear to be relatively free of side effects possibly because neuropeptide systems are only activated under very selective conditions. Peptoid agonists on the other hand can exert extremely powerful actions on brain function and this may be related to the key position neuropeptide receptors occupy in the hierarchy of chemical communication in the brain.

Animals↗
PubMed1992

Family members of patients with sporadic medullary thyroid carcinoma must be screened for hereditary disease.

BACKGROUND: Medullary thyroid carcinoma (MTC), a tumor arising from calcitonin-secreting C cells, appears in either a sporadic nonfamilial or a hereditary form as a component of a multiple endocrine neoplasia syndrome or familial non-multiple endocrine neoplasia MTC. Screening kindred of a patient with familial MTC to detect MTC in the early curable state is standard practice. Opinions conflict about whether it is necessary to screen relatives of patients with apparently nonfamilial MTC to exclude hereditary disease or whether the clinicopathologic features can differentiate between the two forms. METHODS: Clinically well kindred of a patient with MTC that was histopathologically characteristic of the sporadic type were screened for hereditary disease by measurement of plasma levels of basal and stimulated calcitonin. RESULTS: Three of four immediate relatives tested positive for excessive calcitonin secretion and underwent thyroidectomy. All had C-cell hyperplasia, the premalignant phase of MTC. CONCLUSIONS: The patient with apparently sporadic (nonfamilial) MTC was clearly an index case of familial disease. We conclude that clinical presentation and histopathologic examination are not adequate to reliably exclude hereditary MTC. Until genetic markers are readily available to distinguish between sporadic and familial forms, biochemical screening should be done in primary relatives of all patients with newly detected MTC.

Adult↗
PubMed1992

Myxedema coma.

Explore the source record for details and available documents.

Aged↗
PubMed1992

Gait in relation to ageing and idiopathic parkinsonism.

Distance/time measures of gait in 105 sufferers from idiopathic Parkinsonism, who were able to walk unaided, and 144 healthy controls were examined systematically. Those sufferers with overt fluctuations in control were assessed during their "therapeutic window". Free walking speed was lower for a given cadence in the sufferers, but reached a plateau whilst cadence could still be increased. Age, cognitive function and the range of passive hip flexion were important determinants of gait in them. Even minor degrees of cognitive impairment were associated with reduced free walking speed in sufferers: it appears unwise that they were prescribed more sedatives than the controls. The potential benefit of physiotherapy in maintaining joint flexibility was noted. The deficits in speed of individual sufferers, and hence the estimated potential for prophylaxis and treatment, were unrelated to age at presentation. There was no evidence for a limited period of responsiveness to levodopa therapy in this cross-sectional study.

Adult↗
PubMed1991

Inhibition of food intake by omeprazole in the chicken.

Chickens treated with the H+/K+ ATPase inhibitor omeprazole, to inhibit gastric acid secretion, failed to gain weight and showed decreased food intake compared with controls. The gastrin antagonist PD134308 reversed the action of omeprazole on food intake. Since exogenous gastrin decreased food intake, and since omeprazole increased plasma gastrin concentrations, the results suggest that elevated plasma gastrin in chicken exerts a satiety effect.

Animals↗
PubMed1991

Brain membrane protein band 3 performs the same functions as erythrocyte band 3.

We report the presence of band 3 protein(s) in mammalian brain that performs the same functions as those of erythroid band 3. These functions are anion transport, ankyrin binding, and generation of senescent cell antigen, an aging antigen that terminates the life of cells. Structural similarity of brain and erythroid band 3 is suggested by the reaction of antibodies to synthetic peptides of erythroid band 3 with brain band 3, the inhibition of anion transport by the same inhibitors, and an equal degree of inhibition of brain and erythrocyte anion transport by synthetic peptides of erythroid band 3 (pep-ANION 2, residues 588-602; pep-COOH, residues 812-827; pep-COOH-N6, residues 813-818). One of these segments, pep-COOH, contains antigenic determinants of senescent cell antigen. These findings suggest that the transport domains of erythroid and neural band 3 are similar functionally and structurally and support the hypothesis that the immunological mechanism of maintaining homeostasis is a general physiologic process for removing senescent and damaged cells in mammals and other vertebrates.

Amino Acid Sequence↗
PubMed1991

Evidence for an involvement of the brain cholecystokinin B receptor in anxiety.

The effect of neuropeptide cholecystokinin (CCK) receptor agonists and antagonists was examined in the rat elevated X-maze model of anxiety. The selective CCK-B receptor antagonists CI-988 (PD 134308) and L-365,260 produced anxiolytic-like effects, whereas MK-329, a CCK-A receptor antagonist, was respectively less potent by factors of 313 and 200. The intracerebroventricular administration of the nonselective CCK receptor agonist caerulein or the selective CCK-B receptor agonist pentagastrin increased dose dependently the level of anxiety. CI-988 dose dependently antagonized the anxiogenic response to pentagastrin but not that induced by pentylenetetrazol. These results strongly suggest that activation of the brain CCK-B receptor induces anxiety and that selective antagonists of this receptor represent a separate class of anxiolytic agents.

Animals↗
PubMed1991

The major serum protein of Drosophila larvae, larval serum protein 1, is dispensable.

Null alleles of all three genes (alpha, beta and gamma) coding for the major serum protein of Drosophila larvae, larval serum protein 1, have been characterized at the protein level and by analysis of their RNA and DNA. Each allele completely lacks one polypeptide chain. beta shows an unaltered gene but reduced levels of RNA, alpha shows restriction-fragment-length polymorphism and shows low levels of transcript, while gamma is a deletion. The three null alleles have been combined to give a strain without the gene for larval serum protein 1 which survives.

Alleles↗
PubMed1991

Detection of abnormal memory decline in mild cases of Alzheimer's disease using CERAD neuropsychological measures.

The present study was designed to determine which of the memory tasks included in the CERAD (Consortium to Establish a Registry for Alzheimer's Disease) neuropsychological battery best differentiate patients with early Alzheimer's disease from cognitively normal elderly control subjects and also best distinguish between the various levels of severity of the dementia process. A sample of CERAD patients with Alzheimer's disease was stratified by disease severity into those with mild, moderate, or severe dementia and matched with control subjects for sex, age, and education. Using multivariate procedures and cutting scores, the efficacy of each memory measure in distinguishing between these groups and control subjects was determined. The test for delayed recall was found to be the best overall discriminatory measure. The other tests of memory, ie, immediate recall, intrusion errors, and recognition memory, had poor overall discriminability. None of the CERAD memory measures were found to be particularly powerful in staging the severity of dementia. These findings suggest that tests for delayed recall may be particularly useful in the early detection of Alzheimer's disease and should be considered in screening batteries for dementia in community surveys.

Aged↗
PubMed1991

Signs and symptoms from nicotine gum abstinence.

This study examined and compared withdrawal signs and symptoms from cessation of 0, 2 and 4 mg nicotine gum. In addition, a comparison was made between nicotine gum versus cigarette withdrawal symptoms. Smokers first underwent cigarette deprivation for 4 days and then were randomly assigned to 0 (N = 16), 2 (N = 25), and 4 (N = 21) mg gum. They were asked to chew the gum for 1 month and then to undergo a 4-day nicotine gum deprivation period. The results showed a number of significant changes occurring after deprivation from 4 mg gum, one change from 2 mg gum, and no changes from 0 mg gum. There were no significant differences in severity of withdrawal among the various doses of nicotine gum. There were more severe symptoms of withdrawal from cigarette as opposed to 4 mg nicotine gum deprivation.

Adult↗