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Biomedical subjects

R Morris

Publications and source records attributed to R Morris.

At least 289 records · Page 16Linked to original sources
PubMed1990

Sensory responses of caudal trigeminal neurons to thermal and mechanical stimuli and their behavioural correlates in the rat.

Behavioural experiments in the freely moving rat were carried out to determine thermal and mechanical nociceptive thresholds to ramp stimuli applied to the face. The mean thermal escape threshold was 43.5 degrees C, and the mean mechanical escape threshold was 179.2 g/mm2. In a parallel set of experiments recordings were made from single neurons in the caudal trigeminal nucleus of the anaesthetized rat. Neurons were classified according to their responses to a range of thermal and mechanical stimuli applied to the face. Three classes of neuron responded exclusively to mechanical stimuli and four classes responded to thermal stimuli (usually in addition to responding to mechanical stimuli). The mean thermal threshold of neurons responsive to warming stimulation was 44.4 degrees C. Neurons responsive to innocuous warming were located in deeper laminae. Many of the neurons responsive to noxious heat appeared to show an exponential relation between temperature and firing rate. An argument is made for a direct role of exponentially responding neurons in thermal nociception. The distribution of all neuronal response thresholds was left-skewed compared with a normal distribution, whereas the behavioural escape thresholds approximated a normal distribution.

Anesthesia↗
PubMed1990

Detection of human papillomavirus in skin and genital lesions of renal allograft recipients by in situ hybridization.

Renal allograft recipients have an increased incidence of malignancy including squamous carcinoma of cervix and skin. There is growing evidence that human papillomavirus (HPV) has a part to play in malignant transformation at these sites. We have previously identified HPV DNA in the skin and genital lesions of such patients by dot and Southern blotting. In situ hybridization studies, using biotinylated DNA probes for HPV 4, 5 and 8 in skin lesions and 6, 11, 16 and 18 in genital lesions, were performed on tissues derived from the same group of patients. In the cutaneous lesions, only 25% of the specimens probed were found to contain virus by in situ hybridization; 60% of these specimens were found to harbour virus by dot and Southern blotting. In situ hybridization revealed HPV 16 and/or 18 in 86% of the genital lesions probed.

Adult↗
PubMed1990

Rural/urban differences of diabetes--impaired glucose tolerance, hypertension, obesity, glycosolated haemoglobin, nutritional proteins, fasting cholesterol and apolipoproteins in Fijian Melanesians over 40.

Two populations of Fijian Melanesians over 40 years of age were compared. The first population was located in a remote rural area and the other in an urban environment. There was no significant difference between the two populations in age, height and diastolic blood pressure. Highly significant differences were observed in mean weight, body mass index, prevalence of impaired glucose tolerance, prevalence of diabetes, mean glycosolated haemoglobin, mean systolic blood pressure, fasting cholesterol, immunological albumin, immunological transferrin, and A1 and B apolipoproteins. The higher value was associated with urban living. Thus urban living is associated with obesity, impaired glucose tolerance, diabetes, higher systolic blood pressure, higher levels of fasting lipids and increased risk factors for cardiovascular disease.

Apolipoprotein A-I↗
PubMed1990

Circulating and secretory antibodies to specific food proteins in adults.

Indirect enzyme-linked immunosorbent assays (ELISA) for the detection of antibodies to gliadin, beta-lactoglobulin and ovalbumin have been developed. Specific antibody immunoglobulin levels were quantified. Serum and saliva samples were collected from twenty normal subjects and measured for the presence of specific antibodies. For each subject food intake was calculated from a 7-d weighed food inventory record. The total IgG level was 14.2 +/- 4.3 mg/ml (mean +/- s.d.). Levels of beta-lactoglobulin IgG were significantly lower than ovalbumin IgG levels (130 +/- 130 micrograms/ml versus 637 +/- 703 micrograms/ml, P less than 0.01). Gliadin IgG levels were also significantly lower than ovalbumin IgG levels (262 +/- 398 micrograms/ml versus 637 +/- 703 micrograms/ml, P less than 0.05). However, no significant difference was observed between gliadin and ovalbumin IgA levels in the subjects (29 +/- 39 per cent versus 56 +/- 122 per cent). A significant correlation was observed between ovalbumin IgG levels in serum and dietary intake of egg protein (r = 0.46, P less than 0.05). No other significant correlations were observed.

Adult↗
PubMed1990

Labetalol in the control of cardiovascular responses to electroconvulsive therapy in high-risk depressed medical patients.

Labetalol, a drug with alpha- and beta-adrenergic receptor blocking effects, was used to attenuate hypertension and tachycardia associated with electroconvulsive therapy (ECT) in a series of 11 elderly patients with refractory depression and cardiovascular disease in a placebo-controlled, double-blind crossover study design. As compared with placebo, labetalol was found to blunt mean arterial pressure (MAP) increase by up to 8.26% (p less than .001), heart rate increased by up to 26.07% (p less than .001), frequency of atrial arrhythmias by up to 100% (p less than .01), and premature ventricular contractions by 41.97%. No untoward side effects were observed, and no effect on treatment outcome was noted. Labetalol appears to be an effective and safe agent to use in decreasing hypertension, tachycardia, and possibly arrhythmias in high-risk medical patients with cardiovascular disease undergoing ECT.

Aged↗
PubMed1990

Deprivation and health in Scotland.

A measure of deprivation has been devised using data from the 1981 Census about area characteristics which may be considered to reflect material deprivation, and a score is calculated for each postcode sector in Scotland. The routine data sources provide information for a range of health measures which are shown to be strongly linked to levels of deprivation, with specific causes--respiratory conditions, cancer of the lung and cancer of the cervix--exhibiting very considerable differentials in respect of both mortality and cancer morbidity. Nevertheless not all causes exhibit this positive association. This area-based measure provides a valuable tool for the analysis of health data in relation to socio-economic circumstances which overcomes many of the limitations which arise in the use of the more traditional measure of social class. Like social class however it depends on data from the census which are available only at ten-yearly intervals. Other existing data sources are suggested which could possibly provide relevant information on area characteristics and populations for inter-censal years.

Female↗
PubMed1989

Fluoro-Gold injected either subcutaneously or intravascularly results in extensive retrograde labelling of CNS neurones having axons terminating outside the blood-brain barrier.

Subcutaneous or intravascular injections of the dye Fluoro-Gold resulted in widespread labelling of neurones with a distribution and appearance consistent with their being motoneurones, preganglionic autonomic neurones and hypothalamic neurones projecting to the pituitary. Peripheral nerve ligation prevented labelling of neurones whose axons travelled in that peripheral nerve. These observations suggest that Fluoro-Gold diffuses extensively in the body tissues but does not cross the blood-brain barrier and that it is taken up by peripheral terminals and transported retrogradely by motoneurones.

Animals↗
PubMed1989

Responses of spinal dorsal horn neurones evoked by myelinated primary afferent stimulation are blocked by excitatory amino acid antagonists acting at kainate/quisqualate receptors.

The effects of excitatory amino acid antagonists on responses, evoked by myelinated primary afferent stimulation, in neurones of the spinal cord dorsal horn has been investigated in an isolated hemisected spinal cord preparation from the neonatal rat. The first evoked action potential of most responses was reversibly blocked by either 5 mM kynurenic acid (80%) or 10 microM CNQX (91%). The small latency variability and the ability of some of these responses to follow repetitive stimulation suggested that they were evoked monosynaptically. The selective NMDA receptor antagonist, CPP, blocked some later components of responses consisting of bursts of action potentials but not the first evoked action potential. The results support the suggestion that myelinated primary afferents release excitatory amino acids which act at kainate/quisqualate receptors.

6-Cyano-7-nitroquinoxaline-2,3-dione↗
PubMed1989

Deprivation: explaining differences in mortality between Scotland and England and Wales.

To detect reasons for the difference in mortality between Scotland and England and Wales a measure of deprivation was studied, comprising overcrowding, unemployment of men, low social class, and not having a car. Data for Scotland for 1980-2 showed this measure to be strongly associated with mortality, with gradients being particularly steep in young adults. Deprivation was much severe in Scotland than in England and Wales. These findings suggest that much excess mortality may be ascribed to more adverse conditions. Standardising the mortality ratios to take account of the relative affluence and deprivation of the two populations led to the differentials observed being radically adjusted, while standardising for social class had little effect. Deprivation measures based on areas overcome many of the limitations associated with social class analysis and also show much greater discrimination between populations. Measures of deprivation apparently provide a powerful basis for explanation of health differences. Such measures should therefore form part of the 1991 census output to facilitate their use on a consistent basis.

Automobiles↗
PubMed1989

A phase I study of trimetrexate (NSC 352122) administered by 5-day continuous intravenous infusion.

Trimetrexate (TMTX) is a potent inhibitor of dihydrofolate reductase that circumvents the transport resistance seen with methotrexate and has a wide spectrum of preclinical activity. A total of 18 patients with advanced cancer were treated in a clinical and pharmacological phase I trial with TMTX given as a continuous 5-day intravenous infusion. Neutropenia, thrombocytopenia and stomatitis were the dose-limiting toxicities at the maximum tolerated dose of 50 mg/m2 per 120 h (10 mg/m2 per day for 5 days). There was one septic death associated with neutropenia. Other toxicities were mild rash, mild nausea and transiently raised serum transminase levels. Significant relationships between the dose given and the AUC of plasma TMTX and the steady-state plasma level were established. Significant, although weak, relationships between the percentage of change in neutrophils and platelets and both the AUC and steady-state plasma level of TMTX were also observed. No objective tumour responses were seen, although six patients had stable disease. The recommended phase II dose for a continuous infusion of trimetrexate is 40 mg/m2 per 120 h.

Adult↗
PubMed1989

Influence of infusion time on unchanged cisplatin disposition in patients with ovarian cancer.

The disposition of unchanged cisplatin in ten patients with ovarian cancer receiving 2-h infusions of 100 mg/m2 was compared with that of ten patients receiving 6-h infusions. A high-performance liquid chromatographic assay specific for the unchanged drug was used and all collected samples were rapidly processed. Patients were catheterized for urine collections. Cisplatin renal clearance was significantly lower after 6-hour infusions (52.8 +/- 16.2 ml/min per m2) than after 2-h infusions (87.1 +/- 38.2 ml/min per m2) (P = 0.026). Total clearance was also lower and less variable, although not significantly, in patients receiving the longer infusion. No differences in nonrenal clearance, volume of distribution, or half-life were observed between the two groups. There was only a poor relationship between cisplatin renal clearance and creatinine clearance after 2-h (r2 = 0.02; P = 0.66) and 6-h infusions (r2 = 0.18; P = 0.23). A single cisplatin plasma level obtained at the end of the infusion proved to be a good predictor of total cisplatin clearance after both 2-h (r2 = 0.70; P = 0.0096) and 6-h infusions (r2 = 0.97; P = 0.0001). This level was not significantly related to the relatively small changes in creatinine clearance that occurred after three courses of treatment.

Aged↗
PubMed1989

Dosimetric evaluation of a variable energy superficial X-ray machine with applications for endocavitary radiotherapy techniques.

This investigation presents the beam characteristics of a newly-marketed variable energy superficial X ray machine for radiotherapy. The X ray system hardware, including a high voltage generator, and console software allow for nine independent operator-selected X ray beams from 10-150 kVp. Filament current values are also independently variable; 1.0-13.0 mA for 90-150 kVp, and 1.0-30.0 mA for 10-90 kVp. The HVL's, effective energies, and radiation outputs for the nine combinations of kVp and mA are presented. In addition, percentage depth dose and beam uniformity results are presented as a function of cone size. Radiation output stability and reproducibility results are included. Discussion of adaptation of this X ray system to the Papillon technique for the treatment of rectal cancers is presented.

Brachytherapy↗
PubMed1989

Olfactory marker protein gene: its structure and olfactory neuron-specific expression in transgenic mice.

Olfactory marker protein (OMP) genomic clones were isolated from a Charon 4A phage lambda rat genomic library. A 16.5-kilobase (kb) fragment of the rat genome containing the gene was isolated and characterized. Sequence analysis of the gene showed the absence of introns and the lack of CAAT and TATA boxes in the 5' flanking region. The transcription initiation site was mapped, and two sites 55 and 58 base pairs upstream of the ATG were observed. The 5' flanking region is rich in G+C residues and contains a G+C-rich motif as well as direct and inverted repeats. Functional OMP regulatory sequences were demonstrated in transgenic mice. An 11-kb chimeric gene was constructed in which the coding region for OMP was replaced with that for Thy-1.1. In Thy-1.2 mice carrying this transgene, Thy-1.1 was expressed solely by olfactory receptor neurons and their axons and terminals in the olfactory bulb.

Animals↗
PubMed1989

Challenges of aging in tomorrow's world: will gerontology grow, stagnate, or change?

What impact will social, economic, and political trends have over the next decade on services, policies, and research for the elderly? The author predicts that declining confidence in Social Security, questioning of the public's responsibility for the elderly, organization proliferation, anticipated labor shortages, and a trend to reengage in, rather than retire from, mainstream society will all lead to an emphasis on the elderly's productive potential and a "common human need" policy in the aging field.

Aged↗
PubMed1989

Deprivation and mortality: an alternative to social class?

Mortality rates for males aged 20 to 64 in Scotland (1980-1982) display an increasing gradient both by social class (from class 1 to 5) and by the deprivation category of the area (from affluent to deprived) in which the event occurred. Social classes also exhibit gradients in mortality across deprivation categories, the corresponding rates in the most deprived category being around twice those in the most affluent areas. The gradients by deprivation category remain after standardizing for differences in social class composition. Within health boards in Scotland populations show only minor variability in terms of social class, while their composition on the dimension of deprivation is markedly diverse, and the classification of populations by the deprivation category of their area of residence appears to offer a superior basis for the explanation of differences in mortality between health boards than does social class. This evidence of area effects supports a proposal for area socioeconomic characteristics to be adopted as key variables in epidemiological analysis, and for an area classification to be designed and incorporated in the 1991 census output for use on a consistent basis.

Adult↗