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Biomedical subjects

R Payne

Publications and source records attributed to R Payne.

At least 145 records · Page 8Linked to original sources
PubMed1984

Reconstruction of the cervical spine following anterior vertebral body resection: a mechanical analysis of a canine experimental model.

In some quadriplegic patients whose acute spinal injury consists of a vertebral body fracture with bony retropulsion anteriorly and ligamentous damage posteriorly, it is appropriate to perform a decompression of the injured spinal cord by excision of the fractured body. Reconstruction of such a spine to achieve immediate and ultimate stability can be quite difficult. This is a report of mechanical testing using a canine in vitro experimental model to simulate different general types of reconstruction systems applicable to the spine destabilized as above. The results explain some of the previously noted failures of the traditional anterior strut grafting procedures. In addition, one of the reconstruction systems tested (anterior and posterior tension bands compressing an anterior strut graft into place) appeared to have sufficient immediate stability to eliminate the need for a halo-vest in the postoperative period. If such a reconstruction system were to prove clinically applicable, it would be quite beneficial to the quadriplegic patient in his rehabilitation.

Animals↗
PubMed1984

The use of methylmethacrylate cement as an instantaneous fusion mass in posterior cervical fusions: a canine in vivo experimental model.

The authors previously predicted the failure of posterior cervical fusions utilizing methylmethacrylate cement as an instantaneous "fusion" mass, based on research using an in vitro canine experimental model. This report describes the results of in vivo canine studies on the same subject. Three groups of dogs had application of a posterior C4-C5 20-gauge cerclage wire and autologous iliac crest bone graft; application of a posterior C4-C5 20-gauge cerclage wire and methylmethacrylate cement; or application of a C4-C5 20-gauge cerclage wire only. This group represented the control group. The dogs were allowed to live for 3 months postoperatively, at which time they were killed and their spine fusions studied radiologically, mechanically, and histologically. Five of the bone fusions united solidly radiologically. Their flexion stability was statistically superior to the others. Histologic studies confirmed solid union of the fusion mass to the underlying bone. Four of the six methylmethacrylate fusions demonstrated cerclage wire fracture and methacrylate-bone separation by the second postoperative month. At the time the dogs were killed, their flexion stability was statistically inferior to the bone fusions and tended to be inferior to the controls as well. Histologically, fibrous tissue was noted to have grown between the methacrylate "fusion" mass and the underlying bone. This work provides a mechanical explanation for the well-known success of the traditional bony fusion. It further supports our original prediction regarding the failure of methylmethacrylate "fusions."

Animals↗
PubMed1984

Social class and psychological ill-health during unemployment.

This study explores psychological health and the experience of being unemployed for between 6 and 11 months in two social class groups: unskilled and semi-skilled workers v. white-collar, managerial and professional workers. The respondents were British married men aged between 25 and 39. Information was obtained through interviews about financial and other problems, perceived threats associated with unemployment, anxiety, depression, general psychological distress and ratings of general health. It was expected that the working-class sample would exhibit poorer psychological health than the middle-class, but this was not confirmed. Medium-term unemployment appeared to have a homogenizing effect, with similarly poor health in both social class samples, although working-class respondents reported significantly greater financial problems and difficulties in filling the time.

Adult↗
PubMed1984

Advances in the management of cancer pain.

The study of pain in the cancer patient offers a unique opportunity to use clinical observations to advance biologic knowledge. The cancer patient unfortunately represents the experimental model of pain. This group of heroic patients can help teach us the physiologic and psychologic differences between acute and chronic pain, the importance and evolution of psychologic factors, the difference between pain and suffering, the clinical pharmacology of analgesic drugs, and the behavioral mechanisms humans use to suppress pain. They are a rich resource of research potential which should not go untapped. The development of better methods of pain control will benefit all patients with pain. There is a pressing need to develop innovative approaches based on sound, scientific principles, and advances in research technology offer us the opportunity to understand the complex phenomenon of pain.

Analgesics↗
PubMed1983

"Bare lymphocytes" without immunodeficiency.

"Bare lymphocytes," which cannot be typed for the HLA-A,B, and C antigens were observed in two siblings, nine and six years of age. The elder child presented with aplastic anemia and was being considered for bone marrow transplantation. The younger child was healthy. The inability to phenotype both children for these three gene products persisted throughout the 21-month period of observation. The DR antigens were demonstrable which rendered it possible to deduce their A, B, and C genotype from the typing of the other four family members. Although alloantisera failed to detect the antigens on peripheral blood lymphocytes, monoclonal antibodies demonstrated reduced amounts of the HLA-A,B, and C antigens on the cells. The reduced level was confirmed following EBV transformation of the cells. After prolonged culture, HLA antigens immunoprecipitated from the cell extracts were normal in amount, molecular weight, and polypeptide composition. Southern blot analysis did not reveal gross genomic rearrangements. A regulatory defect leading to the expression of these Class I antigens is postulated.

Anemia, Aplastic↗
PubMed1983

Alpha adrenergic receptor subtype associated with receptor binding, Ca++ influx, Ca++ release and contractile events in the rabbit aorta.

The alpha-adrenergic receptor mechanism in rabbit aorta was examined for the involvement of alpha-1 or alpha-2 receptor subtypes. Agonists (phenylephrine, norepinephrine and clonidine) and antagonists (prazosin and yohimbine) with known receptor subtype selectivity were used to define the contribution of alpha-1 or alpha-2 receptors to receptor-initiated cellular Ca++ influx, intracellular release of Ca++ and overall contraction. The receptor content of isolated membranes was also measured in [3H]prazosin and [3H]yohimbine radioligand binding studies. Contraction-derived KB values for prazosin (3 nM) or yohimbine (1 microM) were similar for all three agonists, indicating that each acted on the same alpha-1 receptor. Prazosin (10(-7) M) was effective in causing inhibition of cellular Ca++ influx initiated by agonists whereas yohimbine (10(-6) M) had no effect. Prazosin but not yohimbine caused a partial reduction in phenylephrine or norepinephrine-induced stimulation of 45Ca efflux rate whereas the smaller clonidine-induced stimulation was totally inhibited by prazosin and partially inhibited by yohimbine. Alpha-1 specific binding of [3H]prazosin was observed with a KD of 3.5 nM and maximum binding site (Bmax) of 73 fmol/mg of protein. Although no alpha-2 specific binding of [3H]yohimbine was observed, binding to a low-affinity/high-capacity class of sites was found. The results indicate the sole presence and contribution of alpha-1 receptors to Ca++ flux and contractile events in the rabbit aorta.

Animals↗
PubMed1982

HLA-DR antigens in Chinese-American families.

This paper contains results of a study on HLA-DR antigens in Chinese-American families. DR2, DR4, DRw9, and DRw6Y were the most common DR specificities encountered, and DR1 occurred with the lowest frequency. All recognized DR antigens were observed. The frequency of a blank allele was 6.4-12.8%. Weak serologic reactions with sera primarily of Caucasian origin were not infrequently observed. These findings suggested that ethnic-related antigens were present in this population. Two families showed segregation of a new serologic pattern based on polyspecific sera. The gene frequencies of the BfF allele and the GLO1 allele were low as compared to Caucasians. A method is described for improving the yield of viable B cells from frozen B-lymphocyte preparations.

Asian↗
PubMed1982

Experiences of strain and pleasure among British adults.

Random samples of 1964 men and 1113 women were drawn from the British adult population in order to ascertain the prevalence of unpleasant emotional strain and feelings of pleasure yesterday. Reports of the duration and onset of strain yesterday were also obtained, together with respondents' attributions of causes and stated coping responses. Thirteen percent of men and 18% of women reported experiencing unpleasant emotional strain for at least half of yesterday; corresponding figures for feelings of pleasure for at least half of yesterday were 69 and 68%. Relationships with employment status, age sex, and socio-economic status are described.

Adult↗
PubMed1982

Epidermal growth factor receptor in human epidermal cells: direct demonstration in cultured cells.

The interaction of [125I] labeled murine epidermal growth factor (EGF)( with cultured human keratinocytes has been studied. Epidermal cells from neonatal foreskins were propagated to confluence in 24-well culture trays and incubated with [125I] EGF for binding assays. Association reached equilibrium within 2-4 hr at 4 degrees and slightly earlier at 37 degrees. EGF bound at 37 degrees dissociates very slowly from cells, since it can be shown to enter cells and is degraded to trichloracetic-acid-soluble material. Cells exposed to chloroquine, an inhibitor of lysosomal enzymes, fail to degrade internalized [125I] EGF. Scatchard plots of the binding data yield a dissociation constant of 1 X 10(-9) m and show that epidermal cells bind approximately 3-4 X 10(4) molecules of EGF. Cells exposed to EGF alter their ability to bind EGF by decreasing the number of binding sites in a time- and concentration-dependent manner. Differentiation of epidermal cells in culture poses a problem in assessment of binding of EGF and possibly of other biologically active ligands, since cells lose the ability to bind EGF as they differentiate. These findings indicate that isolated epidermal cells possess a functional receptor for EGF which binds and responds to EGF in a manner similar to that described for other cells.

Animals↗
PubMed1982

Fluoride blocks an inactivation step of transduction in a locust photoreceptor.

1. Photoreceptors in a superfused retina of a locust compound eye are treated with saline containing 10 mM-NaF, while their intracellular resting potential and responses are recorded using glass micropipettes.2. Treatment for two minutes with 10 mM-NaF, followed by a series of brief, bright flashes of light, results in an irreversible, noisy depolarization of approximately 10 mV. The final, stable level of depolarization is reached through the summed effect of each of the noisy, depolarizing afterpotentials that follow every response of the cell to a light flash. If kept in darkness after treatment with NaF, the noisy depolarization still develops, but more gradually, over a period of 5 min.3. The voltage noise induced by NaF mimics light-induced voltage noise when the two are compared at mean depolarizations of more than 15 mV. At very small depolarizations, however, fluoride-induced noise cannot be resolved into the large discrete events (bumps) that are typical of the response of a dark-adapted photoreceptor to a single photon.4. The complete replacement of the superfusate sodium by choline reversibly reduces the fluoride-induced noise and depolarization to the same extent as it does the light-induced noise and depolarization of an illuminated cell.5. Increasing the superfusate calcium concentration from 0.5 to 10 mM also reversibly reduces fluoride-induced noise and depolarization to the same extent as it does light-induced noise and depolarization. This action of calcium is accompanied by an increase in a cell's input resistance which opposes the reduction caused by light or fluoride treatment.6. The results confirm the proposal (Payne, 1981) that anionic metabolic inhibitors cause spontaneous activity in sodium channels that are normally opened by light. A model is proposed in which fluoride acts by blocking the inactivation of a late stage in the transduction mechanism.

Animals↗
PubMed1982

Drainage problems.

Explore the source record for details and available documents.

Maintenance and Engineering, Hospital↗
PubMed1981

The relationship of hookworm infection, anaemia and iron status in a Papua New Guinea highland population and the response to treatment with iron and mebendazole.

In 345 apparently healthy Papua New Guinea male subjects, predominantly highlanders, 89% of whom were infected with hookworm (Necator americanus), there was a statistically significant inverse correlation of hookworm egg count with haemoglobin and serum ferritin level, but no significant correlation with serum albumin, folate or B12 values. A sub-group of 128 was chosen for a six-month study on the effect of treatment with the anthelmintic mebendazole and/or parenteral iron on haemoglobin and serum ferritin levels. Mebendazole-treated subjects remained worm-free and the hookworm egg counts of the controls decreased during the study period. Parenteral iron treatment had the expected effect of raising haemoglobin to a normal level. There was a statistically significant improvement in haemoglobin level in all treated groups but not in the control. Serum ferritin levels decreased significantly in all groups, but more in the control than in the treated groups, although treatment groups were not significantly different. Although probable inadequate uptake of iron by the subjects and blood donation by some subjects was apparently more detrimental to iron status than hookworm infection, the results of this study support the view that hookworm infection in this country contributes to lowered haemoglobin levels and iron status.

Anemia, Hypochromic↗
PubMed1981

Some haematological and physical characteristics of a group of Papua New Guinea highlanders.

Full blood counts and some serum biochemistry were carried out on 349 male and 22 female apparently healthy Papua New Guinea subjects, most of whom were highlanders. In males, RBC, Hb, PCV, MCH, MCHC, serum albumin, ferritin, iron, per cent transferrin saturation and folate means were significantly lower than the Australian normal means; WBC and MCV means were similar to Australian values; and eosinophil and reticulocyte counts and serum transferrin and vitamin B12 means were higher than Australian means. In females, WBC, RBC, Hb, PCV, MCV, MHC, MCHC and serum ferritin means were lower than Australian means; eosinophil counts, serum iron, per cent transferrin saturation, and folate means were similar to Australian means; and serum transferrin and B12 means were higher than the Australian means. Hepatomegaly and mild splenomegaly were common. beta-Thalassemia was present in three subjects two of whom were from Simbu Province.

Adolescent↗
PubMed1980

Linkage disequilibria between HLA-B and the rarer properdin factor B alleles, BfF1 and BfS1.

Phenotypic association and highly significant linkage disequilibria have been demonstrated for HLA-B18 and BfF1 and HLA-Bw50 and BfS1 alleles among Caucasians from Australia and the United States (San Francisco Bay area). The HLA-B18, BfF1 association appears to be associated with HLA-Aw30. It is possible that BfS1 arose as a mutation, after the evolutionary splitting of HLA-Bw21, on an HLA-Bw50 haplotype, and that BfF1 arose on an HLA-Aw30, B18 haplotype.

Alleles↗