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Biomedical subjects

R Morris

Publications and source records attributed to R Morris.

At least 343 records · Page 19Linked to original sources
PubMed1987

Oral protein and energy supplements in cancer patients.

Reduced food intake is a common problem in patients with malignant disease. Oral supplementation is the simplest and least invasive method of increasing the nutrient intake, and a number of neutral protein and energy supplements are available. This study was carried out to assess the value of these supplements when incorporated into the everyday diet of cancer patients. The first stage of the study evaluated the palatability of the energy and protein supplements available. Polycal was found to be the most acceptable energy supplement and Protifar the most acceptable protein supplement. These two products were then used to assess their contribution to the protein and energy intake of cancer patients when incorporated into everyday food. The rise in protein and energy intake was statistically significant but the increase in energy was not thought to be clinically important.

Dietary Carbohydrates↗
PubMed1987

Technical development of an implantable cochlear prosthesis in Canada.

A new cochlear implant device is currently being developed by a group of research teams in Canada. This is an update on the progress of this development, including a brief description of the cochlear electrode array, the implantable stimulator, and the software development for the speech processor.

Cochlear Implants↗
PubMed1986

Developmental classification of reading-disabled children.

The present study developed and used longitudinal cluster analysis, a multivariate classification technique, to classify a sample of 200 nonclinical normal and reading-disabled males based on their performances on a neuropsychological battery at kindergarten, second, and fifth grades. The resulting classification was examined against various internal and external validation criteria. Using a validation framework, five developmental subtypes of children, two normal and three deficit reader groups, were found. Three of these groups could best be described as partitions of a multivariate normal distribution; the other two, both containing deficit readers, showed different covariance structures, suggesting differing developmental patterns. These groups were shown to differ with respect to the domains of academic achievement, parental achievement, neurological status, birth histories, school behaviors, and neuropsychological-cognitive development. The results suggest that developmental classifications can be formed by using multivariate classification methods and the subtypes support findings from cross-sectional classification research on similar populations.

Child↗
PubMed1986

The efficacy and safety of ciprofloxacin in the treatment of chronic Pseudomonas aeruginosa urinary tract infection.

The efficacy of ciprofloxacin in the treatment of chronic Pseudomonas aeruginosa urinary tract infection was assessed in 16 patients with functional or anatomical abnormalities of the urinary tract. Depending on renal function the dosage varied from 100 mg once daily to 250 mg twice daily. All patients were treated for 14 days. Bacteriological cure was documented for seven patients (44%) during the 8 week follow-up period. In a further seven patients the urine was sterile during treatment but relapse occurred within four weeks of completing the course. Persistence was noted in two cases, one of which was associated with the development of resistance. No significant adverse reactions were recorded. Chronic P. aeruginosa infection of the abnormal urinary tract can be very difficult to eradicate and ciprofloxacin may offer a valuable alternative to potentially more toxic parenteral agents.

Adult↗
PubMed1986

Relationship of train-of-four ratio to twitch depression during pancuronium-induced neuromuscular blockade.

The relationship of train-of-four (TOF) ratio to the depression of the first twitch (TD) was investigated in 16 patients given pancuronium in doses insufficient to eliminate the fourth response in the train. In ten patients the block was allowed to spontaneously recover (Group 1) and in six it was reversed with neostigmine (Group 2) once maximum depression of TOF ratio had occurred. Maximum depression of the first response occurred in 6.5 +/- 4.3 min (mean +/- SD). Maximum depression of the TOF ratio was not present until 28.0 +/- 11.0 min. TOF ratio was usually still decreasing when recovery of TD had begun. However, once the TOF ratio began to recover, the recovery rates for TD and TOF ratio were similar in both the spontaneously recovering and the reversed groups. TOF ratio at complete TD recovery was 74.9 +/- 15.7 and 86.2 +/- 15.4% for the two groups. A kinetic analysis yielded significantly different elimination rate constants for the two effects from the "effect compartment." These findings suggest that these two effects of pancuronium are exerted at different sites.

Dose-Response Relationship, Drug↗
PubMed1986

Automaticity, retrieval processes, and reading: a longitudinal study in average and impaired readers.

In this longitudinal investigation, the development of word-retrieval speed and its relationship to reading was studied in 72 average and 11 severely impaired readers in the kindergarten to grade 2 period (5-8 years). Subjects received a battery of 3 reading measures and 4 continuous naming tests with varied stimulus requirements. Results indicated that the relationship of retrieval speed to reading is a function of development and the correspondence between higher- and lower-level processes in the specific retrieval and reading measures. As automaticity in retrieval developed in average readers, naming-speed/reading relationships moved from strong, general predictions to highly differentiated ones. The strongest correlations were between naming speed for graphological stimuli and lower-level reading tasks. Impaired readers performed slower than average readers on all naming measures across all years, particularly on graphological symbols. 3 dyslexic subgroups emerged: the largest was globally impaired across all naming rate and reading tasks; 2 smaller subgroups had early specific, retrieval-rate deficits and dissociated reading deficits.

Child↗
PubMed1986

Critical genetic determinants and molecular events in multistage skin carcinogenesis.

Carcinogenesis can be operationally and mechanistically divided into at least three major stages--initiation, promotion, and progression. Variations among stocks and strains of mice to susceptibility to multistage skin and liver carcinogenesis appear to be more related to alterations in tumor promotion than tumor initiation; however, the critical events have not been determined. In the mouse skin model the first stage is thought to involve the interaction of a tumor initiator with the genetic material of stem cells leading to an alteration in some aspect of growth control, differentiation, or both. The major effect of tumor promoters, regardless of the type, is the specific expansion of the initiated stem cells in the skin. This appears to occur by both direct and indirect mechanisms that involve the loss of glucocorticoid receptors, differentiation alterations, a direct growth stimulation of the initiated cells, or selective cytotoxicity. The progression stage is characterized by a high level of genetic instability that produces a number of chromosomal alterations. These changes may be responsible for the loss of the high-molecular-weight keratin proteins and filaggrin, increase in gamma-glutamyl-transpeptidase activity, and changes in oncogene expression in squamous cell carcinomas. We have found that a high percentage of squamous cell carcinomas have a trisomy in chromosome 2 that carries both src and abl genes and an increased expression of src and abl. We have also found increased Ha-ras on RNA expression in both papillomas and squamous cell carcinomas. We suggest that the genetic instability of the initiated cells is responsible for most observed changes during skin carcinogenesis.

Animals↗
PubMed1986

Factors associated with achieving continuity of care in general practice.

The continuity of care received by 128 patients in four Bristol group practices over a two-year period was measured. A high standard of continuity of care was found for many patients, even though they were registered with large training practices. Patients registered with practices operating personal lists received much better continuity of care than those registered with practices operating combined lists.Patients in the study regarded continuity of care as important, especially if they were registered with practices operating personal lists.All the doctors in the study appeared to regard continuity of care as important, although those operating personal lists were more positive in this view.

Adolescent↗
PubMed1985

Evaluation of a computer assisted repeat prescribing programme in a general practice.

After introducing a computer assisted repeat prescribing programme into a south London practice improvements were made in several aspects of practice organisation. Time was saved by doctors and receptionists; prescriptions were produced more rapidly; information in the records about drugs that were available for repeat prescription was improved; and queries from chemists about prescriptions were reduced. The costs of the system in terms of computer operator time were estimated. Computerising prescribing data provides a source of data that may be used to enable doctors to audit their own prescribing.

Computers↗
PubMed1985

Genetic variability of flight metabolism in Drosophila melanogaster. II. Relationship between power output and enzyme activity levels.

The major goal of the studies reported here was to determine the extent to which genetic variation in the activities of the enzymes participating in flight metabolism contributes to variation in the mechanical power output of the flight muscles in Drosophila melanogaster. Isogenic chromosome substitution lines were used to partition the variance of both types of quantitative trait into genetic and environmental components. The mechanical power output was estimated from the wingbeat frequency, wing amplitude and wing morphology of tethered flies by applying the aerodynamic models of Weis-Fogh and Ellington. There were three major results. (1) Chromosomes sampled from natural populations provide a large and repeatable genetic component to the variation in the activities of most of the 15 flight metabolism enzymes investigated and to the variation in the mechanical power output of the flight muscles. (2) The mechanical power output is a sensitive indicator of the rate of flight metabolism (i.e., rate of oxygen consumption during tethered flight). (3) In spite of (1) and (2), no convincing cases of individual enzyme effects on power output were detected, although the number and sign of the significant enzyme-power correlations suggests that such effects are not totally lacking.

Animals↗
PubMed1985

Thy-1 in developing nervous tissue.

Thy-1 is a developmentally regulated cell surface glycoprotein, found at high levels in nerve and certain other tissues. In brain its level rises nearly 100-fold during early postnatal development, but until recently the cellular basis of this, or even the distribution of Thy-1 in adult nervous tissue, has been unclear. On the other hand considerable progress has been made in elucidating the gene, and protein and carbohydrate structure of this molecule, so that the basis for its developmental regulation, and possibly its function, is beginning to emerge. In adult nervous tissues Thy-1 appears to be a surface component of most neurons, although within the CNS the density of antigen varies considerably on different cell types. Early in development, however, Thy-1 is present on only certain neurons--for instance on Purkinje cells in cerebellar cortex--and Thy-1 immunohistochemistry can demonstrate new aspects of the development of such cells. During development, previously Thy-1-negative cells can acquire high levels of Thy-1, and conversely detectable antigen can be lost from cells which at earlier stages stained intensely in Thy-1 immunohistochemistry. Such developmental changes can occur in waves of maturation which are defined spatially as well as temporally. Changing patterns of Thy-1 expression are also found at some sites in nervous tissue after axonal injury. The evidence for a role for Thy-1 in nervous system development is discussed, both in terms of its changing distribution during development and in the light of more direct attempts to define its role on the cell surface.

Aging↗
PubMed1984

The effects of oxytocin and vasotocin analogues on the responses of rat brainstem neurones to oxytocin.

The effects of microiontophoretically applied oxytocin on the firing rates of neurones in the rat caudal brainstem have been examined. Of the sample of 156 units recorded the firing rates of 33.3% were reduced and those of 21.2% were raised by microiontophoretically applied oxytocin, whilst the remainder were unaffected. The distribution of units facilitated by oxytocin tended to overlap with the distribution of oxytocin demonstrated immunocytochemically, whereas many units inhibited by oxytocin were in regions where no oxytocin was observed. Overall the excitatory but not the inhibitory effects of oxytocin could be blocked by oxytocin and vasotocin analogues with antagonist properties.

Animals↗
PubMed1984

The effects of microiontophoretically-applied opioids and opiate antagonists on nociceptive responses of neurones of the caudal reticular formation in the rat.

Opioids, when applied by microiontophoresis to caudal reticular neurones (CRF) in the rat, were found to be predominantly inhibitory in action. When the actions of a series of analogues of enkephalin, that have very different potencies on peripheral tissues, were applied microiontophoretically to caudal reticular neurones, only small differences in their ability to depress the firing of these neurones were observed. Analogues of enkephalin with differing affinities for mu- and delta-receptors also produced comparable inhibitions of neuronal activity. These inhibitory actions were reduced by opiate antagonists. Many caudal reticular neurones have peripheral receptive fields which are activated by noxious stimuli. Excitatory responses produced by noxious stimuli were depressed by microiontophoretically-applied opioids and this effect was antagonised by naloxone or naltrexone. The reduction in firing rate evoked in some neurones by peripheral noxious stimulation was very resistant to change when opiate antagonists were applied microiontophoretically but could sometimes be totally blocked by systemic injection of opiate antagonists.

Action Potentials↗
PubMed1984

Dichotic listening ear asymmetry: patterns of longitudinal development.

Dichotic listening research with children has continued to be prevalent although numerous authors have described both theoretical and methodological limitations with traditional dichotic listening free-recall paradigms. The present research adds to this growing skepticism by reanalyzing two major longitudinal studies of children's ear asymmetries. These two studies, based in different countries (United States, Holland), utilized highly similar paradigms (free-recall digits), subjects (males), and age levels (kindergarten and second and fifth grade). The questions of ear advantage development, patterns of ear advantages, and the relationship between dichotic listening performance and reading skills are addressed from the multiple statistical methodologies represented in the literature. From these analyses, support for all of the major hypotheses regarding the developmental patterns of dichotic listening performances could be obtained from the same data samples. The use of traditional free-recall dichotic listening paradigms are not recommended for use with children. The implications for future research are discussed.

Child↗