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Biomedical subjects

R J Morris

Publications and source records attributed to R J Morris.

At least 19 recordsLinked to original sources
PubMed1996

Normal spatial learning despite regional inhibition of LTP in mice lacking Thy-1.

The process of learning involves stable changes in synaptic efficacy for which long-term potentiation (LTP) provides a widely adopted mammalian model. Synaptic modification induced by learning or LTP may involve the action of cell adhesion molecules. One such candidate is the ubiquitous neuronal glycoprotein Thy-1. In mice in which the gene encoding Thy-1 has been inactivated, we find a regionally selective impairment of LTP in vivo in the hippocampal formation: LTP is normal in area CA1 but strongly inhibited in the dentate gyrus. Spatial learning by Thy-1-deficient mice, as assessed in the watermaze, is unimpaired. Thus LTP in the cortical input to the dentate gyrus seems not to be required for spatial learning.

Animals↗
PubMed1996

Internal thoracic artery for coronary artery grafting in octogenarians.

BACKGROUND: Use of the left internal thoracic artery as a bypass graft has been shown to result in better long-term patency and improved survival. In elderly patients, the internal thoracic artery has been used less often for coronary artery bypass grafts because of the belief that greater morbidity and mortality are associated with this procedure. This study was undertaken to test this premise in the octogenarian population. METHODS: Over an 8-year period, 474 consecutive patients 80 years of age and greater had coronary artery bypass grafting. The left internal thoracic artery was used in 188 patients (39.7%) (group 1) and saphenous vein grafts only (group 2), in 286 (60.3%). The mean age was 82.6 years (range, 80 to 95 years). There were 312 men (65.8%) and 162 women (34.2%). RESULTS: Use of the internal thoracic artery as a graft has risen steadily each year, as has the number of patients who are octogenarians. The hospital mortality rate was 7.8%. Patients in group 1 had a mortality rate of 9.0% and patients in group 2, a mortality rate of 7.0%. The mortality rate among survivors at 1 year was 6.7%. Long-term survival was significantly greater in group 1. CONCLUSIONS: On the basis of this study, we conclude that the internal thoracic artery is the bypass graft of choice, especially in regard to long-term mortality, and should not be denied to this high-risk group.

Age Distribution↗
PubMed1996

Comfortable effort level revisited.

The purpose of this study was to measure the variability of frequency and intensity of speech, using multiple voice samples obtained over a period of time at a speaker's "comfortable effort level." Variability in vocal output within and across several experimental sessions was assessed from measures of speaking fundamental frequency (SFF) and vocal intensity for utterances repeated three times a day over a 3-day period. Three distinct age groups of men and women-young, middle-aged and elderly-repeated the vowel /a/, read a standard passage, and spoke extemporaneously during each experimental session. Results indicated that variability in SFF and intensity were present across experimental sessions, age groups, gender, and speaking samples. Generally, group means indicated that approximately +/- 1 semitone of variability for SFF and approximately 2 db sound pressure level (SPL) variation in vocal intensity from any one experimental session to the next could be expected; individual variations within any group may reach two semitones and 6 db SPL.

Adult↗
PubMed1996

Comparison of various automatic means for measuring mean fundamental frequency.

The purpose of this paper was to evaluate the reliability of, and agreement among, six speech analysis systems in the determination of fundamental frequency. Five male and five female speakers provided oral reading and sustained vowel samples for analysis. Each sample was analyzed five times by each system. The results indicated high reliability for all of the systems for both sexes and both utterance types. Agreement among the systems was high for the male sustained vowels and the female oral reading samples. In contrast, poor agreement occurred among the systems for the male oral reading samples and the female sustained vowels. The findings indicate that the output of these automatic methods tends to be consistent over repeated trials within the systems in their extraction of fundamental frequency; however, agreement among these systems varies.

Adolescent↗
PubMed1996

Further contrasts between self-reflectiveness and internal state awareness factors of private self-consciousness.

Although widely used as a unitary measure of self-focused attention, the Private Self-Consciousness subscale (Fenigstein, Scheier, & Buss, 1975) contains two factors. In the present study, this subscale and its self-reflectiveness (SR) factor predicted greater shame, guilt, other-directedness, and social anxiety; but the internal state awareness (ISA) factor displayed relationships that were in the opposite direction. Contrasts between SR and ISA often became more obvious in partial correlations, when one factor was examined while controlling for the other. In relationships with personal and social identity, SR appeared to reflect public as much as private self-consciousness. These data support recent suggestions that it may be necessary to construct more adequate measures of private self-consciousness.

Adolescent↗
PubMed1996

Asthma. Specific preventive strategies.

Asthma can be a destructive disease over time, resulting in partially irreversible obstruction. Early intervention is essential, and preventive strategies are preferred to treatment for flare-ups. These strategies include intensive patient education and constant monitoring of airflow as well as effective pharmacotherapy and management of concomitant disorders and side effects. Because allergy is a component in half or more of patients, consultation with an allergist is recommended. New agents for both oral use and inhalation are either in development or will soon be available.

Anti-Asthmatic Agents↗
PubMed1996

Torticollis secondary to ocular pathology.

We report a series of 15 children, six male and nine female, of average age 20 months, seen at a paediatric orthopaedic clinic with torticollis. Orthopaedic examination revealed a normal range of neck movement in all cases but in seven there was palpable tightness in the absence of true shortening or contracture of the sternomastoid muscle. The patients were prospectively referred for ocular examination. In five of the 15 an ocular cause for the torticollis was detected with underaction of the superior oblique muscle in three, paresis of the lateral rectus muscle in one and nystagmus in one. Another two patients were found to have an abnormal ocular examination which was thought to be unrelated to their torticollis. Three of the patients with ocular torticollis required extra-ocular muscle surgery to abolish the head tilt and one of these had a tight sternomastoid muscle. Two of the non-ocular group had surgical release of the sternomastoid muscle; in the rest, the condition either resolved with physiotherapy or required no active treatment. We recommend that all patients with torticollis and no clear orthopaedic cause are referred for ocular assessment since it is not possible clinically to distinguish ocular from non-ocular causes.

Adolescent↗
PubMed1995

NCAM requires a cytoplasmic domain to function as a neurite outgrowth-promoting neuronal receptor.

The neural cell adhesion molecule (NCAM) promotes axonal growth via a homophilic binding mechanism by acting both as a neuronal receptor and a substratum ligand. We have previously shown that the GPI-linked 120-kDa isoform of NCAM, which lacks a cytoplasmic domain, is effective at promoting neurite outgrowth as a cellular ligand. To test its ability to function as a neuronal receptor, we have transfected PC12 cells with a cDNA encoding human GPI-linked NCAM and tested clones displaying stable cell surface expression of this isoform for their ability to respond to NCAM in a cellular substratum. Although they continued to express endogenous transmembrane rat isoforms of NCAM (140 and 180 kDa), PC12 cells expressing the GPI-linked NCAM lost their ability to extend neurites in response to substratum associated NCAM. However, their outgrowth response to N-cadherin and other activators of axonal growth was undiminished. Removal of GPI-linked NCAM from the surface of these clones using phosphatidylinositol-specific phospholipase C (PIPLC) fully restored their responsiveness to NCAM, indicating that the inhibition was a direct consequence of cell surface expression of this "dominant negative" isoform of NCAM. We have previously shown that expression of transfected 140- and 180-kDa isoforms of human NCAM in PC12 cells does not result in a loss of the neurite outgrowth response to NCAM. However, we show that deletion of the cytoplasmic domain of the 140-kDa isoform has the same effect as expression of GPI-linked NCAM. We conclude that the cytoplasmic domain of NCAM is required for an appropriate neurite outgrowth response.

Animals↗
PubMed1995

Uptake of organochlorines (chlorobiphenyls, dieldrin; total PCB & DDT) in bottlenose dolphins (Tursiops truncatus) from Cardigan Bay, west Wales.

High concentrations of organochlorine compounds (particularly PCB and chlorobiphenyls) have been found in three bottlenose dolphins from the vicinity of New Quay in West Wales. Although few in number, the animals ranged in age from 10 months to 23 years. The occurrence of high contaminant concentrations in all of these animals suggests that a high level of uptake of these compounds occurs in food after weaning as well as by transfer from mother to calf. In order to investigate this further we have tried to model the uptake using a bioenergetics-based approach. Using estimates of feeding rate we have calculated the concentrations of these contaminants in average prey items necessary to maintain the dolphin's body burden during the juvenile growth stage. The data available to date are too few for a rigorous test of this approach, however these preliminary studies suggest that the contaminant concentrations in local food items analysed to date are not sufficiently high to explain the high concentrations found in dolphin blubber. Further information is needed on the contaminant burdens of bottlenose dolphins in Cardigan Bay, and of their relationships and diet (including seasonal and migratory components), in order to validate this approach.

Age Factors↗
PubMed1995

Patterns of fundamental frequency for three types of voice samples.

The purpose of this study was to determine the variability in speaking fundamental frequency (Fo) associated with sample type in two age groups of normal male and female speakers and a group with vocal-fold paralysis. Young and elderly normal control men and women produced a sustained vowel, read a passage, and spoke extemporaneously in the morning, early afternoon, and late afternoon on three different days. The vocal-fold-paralysis group produced two voice samples at different times on the same day. Two patterns of variability emerged in the normal groups. Young men produced sustained phonation at a significantly lower Fo than their reading or extemporaneous samples. Young and older women and older men produced sustained phonation with a higher Fo than their reading or extemporaneous samples. The eight subjects with unilateral vocal-fold paralysis (seven women, one man) produced samples with a pattern similar to that of the older normal groups but with greater differences between the sustained vowel and speech samples. The use of different sample types resulted in variations in mean speaking Fo in the normal subjects as well as in the vocal-fold-paralysis group. Within-day sampling of all normal subjects resulted in approximately the same variability as across-day sampling. In the vocal-fold-paralysis group, within-day sampling resulted in greater variability of mean Fo for vowels than for connected speech, following a pattern similar to the older normal control subjects and various speech materials for voice.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Phonational profiles of male trained singers and nonsingers.

The purpose of this study was to compare the mean speaking fundamental frequency (SFF), speaking frequency range, and mean speaking intensity for a group of trained male singers and a group of age-matched non-singers in three age ranges: 20 to 35 years old; 40 to 55 years old; and older than 65 years. Each subject was recorded as he read "The Rainbow Passage" and produced the vowel /a/ to the limits of his phonational frequency range. The data indicated that the mean SFF of the nonsingers was significantly lower among the middle-aged speakers than with the young or elderly. In contrast, the tenors exhibited no age-related SFF trends, and the young bass/baritones exhibited lower SFF levels than the middle-aged or elderly. The elderly nonsingers produced frequency ranges that were smaller than any other group. Finally, the young nonsingers used greater speech intensity than did the other groups.

Adult↗
PubMed1995

Narcissism, self-esteem, and parental nurturance.

Self-reported narcissism, self-esteem, and perceptions of parents as nurturing were examined in a sample of 459 undergraduates. In zero-order and partial correlations, dimensions from the Narcissistic Personality Inventory displayed inter-relationships and linkages with self-esteem and parental nurturance that conformed with the hypothesis that indices of narcissism fall along a continuum of mental health. Partial correlations controlling for self-esteem also indicated that at least some data for the more adaptive aspects of narcissism were mediated by healthier self-functioning. These results support recent suggestions that narcissism must be conceptualized within frameworks that include healthy self-esteem.

Adaptation, Psychological↗
PubMed1995

The glycophosphatidylinositol anchor affects the conformation of Thy-1 protein.

Thy-1 has the structure of a single variable-type immunoglobulin domain anchored to the external face of the plasma membrane via a glycophosphatidylinositol moiety. When the lipid is removed from this anchor by either phospholipase C or D, the reactivity of the delipidated Thy-1 for a range of antibodies, including those known to be determined by amino acid residues, is impaired. We have investigated in detail the effect of delipidation on the reaction with the OX7 monoclonal antibody, determined by the allelic variant residue Arg 89. Analysis of the kinetics of OX7 binding shows that delipidation affects primarily the dissociation of antibody, increasing the dissociation rate constant kdiss from 0.27 x 10(-3) s-1 to 2.39 x 10(-3) s-1. Addition of phospholipase to preformed antibody-antigen complex causes an immediate change from the slow to the faster dissociation rate, implying that delipidation induces a conformational change in the Thy-1 protein that is sufficiently strong to dissociate bound antibody. This conformational change can be demonstrated directly by the circular dichroism spectrum of human Thy-1 that detects changes in the environment of Tyr residues located near the antigenic epitopes. Molecular dynamics studies suggest that, on delipidation, a conformational change occurs in the glycan chain that affects the protein in the region of the antigenic epitopes. This study thus demonstrates that the glycophosphatidylinositol anchor strongly influences the conformation of Thy-1 protein by a mechanism that could occur generally with membrane proteins of this class.

Amino Acid Sequence↗
PubMed1994

Salmeterol xinafoate as maintenance therapy compared with albuterol in patients with asthma.

OBJECTIVE: To compare the efficacy and safety of inhaled salmeterol xinafoate, a long-acting beta 2-adrenoceptor agonist, with that of albuterol, a short-acting inhaled beta 2-agonist, in the treatment of asthma. DESIGN: Randomized, double-blind, placebo-controlled, parallel-group study. SETTING: Eleven outpatient clinical centers. SUBJECTS: A total of 322 male and female patients at least 12 years of age with chronic symptomatic asthma requiring daily therapy. INTERVENTION: Patients were treated with salmeterol xinafoate (42 micrograms inhaled twice daily), albuterol (180 micrograms inhaled four times daily), or placebo (four times a day) for 12 weeks; patients in all three groups could use inhaled albuterol as backup medication for breakthrough symptoms. MAIN OUTCOME MEASURES: Serial 12-hour forced expiratory flow in 1 second (FEV1), peak expiratory flow (PEF), asthma symptoms, nocturnal awakenings due to asthma, episodes of asthma exacerbations, and electrocardiography. RESULTS: The mean area under the curve for FEV1 throughout each 12-hour period was consistently greater after a single dose of salmeterol than after two doses of albuterol administered 6 hours apart (P < .001), with the difference ranging from 3.1 to 4.3 L.h. Salmeterol produced an average increase in morning and evening PEF of 26 and 29 L/min, respectively, over pretreatment values compared with decreases of -13 and -3 L/min, respectively, in the albuterol group and -2 L/min both in the morning and evening in the placebo group (P < .001). Patients in the salmeterol group had significantly fewer days and nights with symptoms than did either the albuterol or placebo group (P < .001). Responses to salmeterol were similar at day 1 and at week 12. Adverse events in all treatment groups were equally infrequent, and no clinically significant change in cardiac rhythm was observed with salmeterol treatment. CONCLUSION: Salmeterol inhaled twice daily is more effective than albuterol inhaled four times a day (or as needed) in patients with asthma requiring maintenance therapy. No deterioration of asthma control was observed with the use of salmeterol over a 3-month period.

Administration, Inhalation↗
PubMed1994

Age-related differences in speech variability among women.

The purpose of this study was to examine the differences in variability of several measures of the speech produced by two groups of women, one aged 20-35 years and one aged 75 years and over. The subjects read the first paragraph of the "Rainbow Passage," sustained vowels at three loudness levels, and repeated a carrier phrase in which a series of 18 syllables were embedded. Data were gathered on intraoral pressure (PIO), vocal intensity, speaking fundamental frequency (SFF), voice onset time (VOT), and phoneme duration. The F-max test and ANOVA statistics revealed that the older women exhibited greater within-subject variability than the younger women for PIO, SFF, VOT, and consonant duration. These factors required more precise temporal, respiratory, phonatory, or articulatory adjustments than did the vocal intensity tasks or vowel duration. The variability differences found in this study may reflect individual patterns of acoustic and physiologic change in the speech produced by older women.

Adult↗
PubMed1994

The use of Prolene as a temporary suspensory material for brow suspension in young children.

Children with severe, unilateral congenital ptosis are at risk of developing amblyopia if the lid obscures the visual axis. In this situation, urgent repair of the ptosis is indicated. These patients generally have very poor function of the levator palpebrae superioris muscle and a brow suspension is required. The suspensory material which gives the best long-term results is autogenous fascia lata. In young children, however, there is insufficient autogenous fascia available. We reviewed 9 patients aged 4 years or less who had undergone surgery for congenital ptosis. In each case a brow suspension was performed using 4/0 Prolene (monofilament polypropylene) suture as a temporary suspensory material. All patients achieved a satisfactory result with the upper lid remaining clear of the visual axis during a mean follow-up period of 18.7 months (range 8-29 months). We suggest that Prolene suture is a readily available material which is suitable as a temporary suspensory material for brow suspension in very young children.

Amblyopia↗