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Biomedical subjects

R M Jones

Publications and source records attributed to R M Jones.

At least 163 records · Page 9Linked to original sources
PubMed1991

Reduction of cold injury by superoxide dismutase and catalase.

The pathophysiology of cold injury was examined by cooling a hind leg of an anesthetized New Zealand white rabbit. A flow probe and a thermocouple were placed in the leg to be cooled to monitor the blood flow and tissue temperature. After baseline measurements, the leg was cooled with a freezing mixture up to 0 degrees C, which was followed by rewarming. The other leg served as control. In the experimental group, liposome-bound superoxide dismutase and catalase were infused through the femoral vein 15 minutes prior to putting the freezing mixture on the leg. Salicylic acid was injected through the femoral vein at the end of some experiments to assay hydroxy radical (OH). Our results demonstrated reduction of local blood flow in cold-exposed leg, indicating development of ischemia. Creatine kinase and lactage dehydrogenase were increased during rewarming in conjunction with hydroxyl radical formation, phospholipid breakdown, and lipid peroxidation. Treatment with superoxide dismutase and catalase reduced OH formation, prevented phospholipid degradation, and decreased creatine kinase, lactate dehydrogenase, and malonaldehyde formation. These results indicate that rewarming of cooled tissue is associated with "rewarming injury" similar to "reperfusion injury", and that oxygen-derived free radicals play a significant role in the pathophysiology of such injury.

Animals↗
PubMed1991

The days ahead.

How are government controls affecting healthcare foodservices?Are growing elderly & outpatient populations changing foodservices' missions. What are the hottest trends? As members of the American Society for Hospital Food Service Administrators prepared for their annual meeting in Orlando, FM queried 11 Southeastern directors to learn their most pressing concerns & how they are positioning their departments for the future.

Aged↗
PubMed1990

Clinical impressions and cardiorespiratory effects of a new fluorinated inhalation anaesthetic, desflurane (I-653), in volunteers.

The new volatile anaesthetic, desflurane (I-653), was administered to 10 healthy, unpremedicated young male volunteers in order to determine its cardiorespiratory effects and the characteristics and acceptability of its inhalation. All volunteers breathed either sub-anaesthetic (1.8% inspired) or anaesthetic (5.4% inspired) concentrations of the anaesthetic without coughing, breath-holding, salivation or other untoward respiratory response. Respiratory minute volume and alveolar ventilation decreased and ventilatory rate increased. Systemic arterial pressure decreased (diastolic more than systolic) and heart rate remained unchanged. Cardiac rhythm remained unaltered, except in one volunteer who experienced a single premature atrial contraction. Volunteers stated that the odour of desflurane was not irritating or unpleasant. Exposure to the agent for approximately 90 min resulted in rapid and clear-headed recovery.

Anesthesia Recovery Period↗
PubMed1990

Neuromuscular block with doxacurium (BW A938U) in patients with normal or absent renal function.

The characteristics of neuromuscular block induced by doxacurium were compared in patients with and without renal function. Seventeen patients with end stage chronic renal failure and 18 patients with normal renal function were anaesthetized with 0.5% halothane and nitrous oxide in oxygen and received doxacurium in an initial dose of 25 micrograms kg-1 (estimated from available data as an ED95 dose), with incremental doses of 5 micrograms kg-1. At the end of surgery, residual neuromuscular block was antagonized with either edrophonium 1.0 mg kg-1 or neostigmine 0.08 mg kg-1. There was no significant difference between the mean maximum blocks achieved with doxacurium: 17.4% (renal failure group) and 11.6% (control group) of control twitch heights, or between the mean times to achieve maximum block (10.9 min and 10.8 min, respectively). The mean duration of action of doxacurium, indicated by the time for twitch height to recover to 25% of control, was longer in the renal failure group (120.8 min vs 66.7 min in the control group) (ns). Similarly, the mean duration of action of increments was longer in the renal failure group (27.4 min vs 20.5 min in the control group). The rate of spontaneous recovery from doxacurium as indicated by the time for twitch height to recover from 0 to 5%, 5 to 10% and 10 to 25%, was not significantly different in the two groups. Antagonism of doxacurium was achieved more reliably with neostigmine than with edrophonium in both groups. The administration of doxacurium was associated with minimal cardiovascular effects.

Adult↗
PubMed1990

Biotransformation and hepato-renal function in volunteers after exposure to desflurane (I-653).

Ten healthy unpremedicated male volunteers were exposed to an average inspired concentration of 3.6% desflurane (I-653) in oxygen for 89 (SD 17) min. Standard haematological and biochemical tests were performed before (control) and immediately after exposure and at 4, 24, 72 and 192 h. Liver function was assessed at these times by determining total and unconjugated (indirect) bilirubin, and plasma concentrations of aspartate amino transferase, alanine amino transferase, gamma-glutamyl transpeptidase and alkaline phosphatase. Renal function was assessed by examining the urine microscopically for leucocytes, red blood cells, casts and crystals at these times, and creatinine clearance and urine concentrating ability were determined before and 24 and 72 h after exposure. Two additional and sensitive tests of renal integrity were performed before and 4 and 24 h after anaesthesia: measurement of urinary retinol-binding protein and beta-N-acetyl-D-glucosaminidase. Serum inorganic fluoride was determined immediately before and 1, 4, 24, 48, 72 and 192 h after anaesthesia. Urinary inorganic and organic fluoride concentration and excretion rate were determined before and 24, 48, and 72 h after anaesthesia. There were no significant changes in any measured haematological or biochemical variable (other than an increase in total white cell count from 5.9 (1.3) to 8.3 (1.1) x 10(9) litre-1 immediately after exposure) nor in liver or renal function tests. There was no increase in serum or urinary inorganic fluoride or urinary non-volatile organic fluoride concentrations.

Anesthetics↗
PubMed1990

Complement activation in psoriasis.

Plasma from 16 patients with psoriasis and 12 healthy control subjects were measured for iC3b, C4d, and Bb fragments generated by complement activation. Plasma concentrations for iC3b, C4d, and Bb fragments were found to be significantly increased in the patients with psoriasis. The highest concentrations of these complement activation fragments were seen in patients with erythrodermic pustular psoriasis, psoriatic arthritis, and Reiter's syndrome. The serum concentrations of complement components and regulatory proteins were normal or elevated in almost all samples.

Complement Activation↗
PubMed1990

Role of iron on membrane phospholipid breakdown in ischemic-reperfused rat heart.

Oxygen-derived free radicals have been implicated in causing degradation of myocardial membrane phospholipids associated with ischemia and reperfusion. Since iron is known to catalyze the hydroxyl radical formation responsible for cellular injury, this study was designed to relate the role of iron with phospholipid breakdown in ischemic-reperfused heart. Isolated rat heart perfused by the Langendorff technique was subjected to 30 min of normothermic ischemia followed by 30 min of reperfusion. The experimental group received 0.6 mM deferoxamine, an iron chelator, before reperfusion of ischemic myocardium. Deacylation and reacylation of membrane phospholipids were monitored by using [14C]arachidonic acid (AA), whereas the de novo phospholipid synthesis was evaluated by using [3H]glycerol in the perfusate. In the deferoxamine group, the loss of [14C]phosphatidylcholine (PC) and the corresponding accumulation of isotopic lysophosphoglycerides as well as AA was significantly lower compared with the control. The incorporation of radioactivity for [14C]AA and [3H]glycerol into phospholipids was significantly increased in the treated group compared with the untreated group. In addition, decreased malonaldehyde formation and lactate dehydrogenase release, a higher recovery of high-energy phosphate compounds, and myocardial contractility were noticed in the deferoxamine-treated hearts. These results indicated that postischemic administration of an iron chelator such as deferoxamine can preserve membrane phospholipids and reduce myocardial dysfunction associated with reperfusion of ischemic heart.

Acylation↗
PubMed1990

Kinetics and potency of desflurance (I-653) in volunteers.

The inhalation anesthetic, desflurance (I-653), is a methyl ethyl ether halogenated entirely with fluorine and differing from isoflurance only in the substitution of fluorine for chlorine on the alpha-ethyl carbon. Relative to presently used potent inhalation anesthetics, desflurane has low blood/gas (0.42) and oil/gas (18.7) partition coefficients. These indicate that it will undergo rapid washin and washout (and hence rapid induction of and recovery from anesthesia) and have a MAC value of about 5%. In the present study we demonstrate that desflurane possesses these characteristics in healthy young volunteers. After a 10-min exposure to desflurane the ratio of alveolar (FA) (determined by end-tidal sampling) to inspired (FI) concentration (FA/FI) was 0.82. Washout was similarly rapid; 10 min after discontinuing administration of desflurane, the alveolar concentration relative to the last concentration during administration of anesthetic (FAO) was 0.11 (FA/FAO). These values are similar to those for nitrous oxide. Volunteers responded to commands an average of 2.7 min after discontinuing anesthetic administration. The values for MAC-awake and MAC (the latter determined by tetanic stimulation of the ulnar nerve using surface electrodes) were 2.42% and 4.58% and the ratio of the former to the latter was 0.53.

Adult↗
PubMed1990

Teacher characteristics and competencies related to substance abuse prevention.

Teacher characteristics and competencies perceived as beneficial for preventing substance use among students were identified through a literature search, review of existing prevention curricula, and consultation with state and local experts. These qualities were integrated into a questionnaire and administered to acknowledge professionals in the substance use and abuse arena who were affiliated with universities, public schools, and prevention/intervention agencies. A factor analysis yielded six constructs which were then scaled, examined for psychometric appropriateness, and subsequently employed to quantify perceptions of importance. Teacher-Student Relations emerged as the most important aspect of teacher comportment, followed by knowledge associated with Human Behavior, Substances, User Recognition and Referral, Prevention Curricula, and Legal Issues. These findings are encouraging in that the characteristics and skills perceived as important to prevention can be developed in both pre- and in-service teacher training.

Adult↗
PubMed1989

Effects of oxyradicals on oxymyoglobin. Deoxygenation, haem removal and iron release.

We have examined the effects of O2-derived free radicals on oxymyoglobin, the myocardial intracellular protein involved in the storage and transport of O2. The oxyradicals generated by the xanthine/xanthine oxidase system decreased the concentration of oxymyoglobin. Based on the decreases in absorbance peaks at 581 nm and 415 nm it is estimated that out of a 10 nmol decrease in oxymyoglobin, 5 nmol appears to be oxidized to ferrimyoglobin (deoxygenation), while haem was removed from the other 5 nmol of haem protein. These processes were inhibited by both catalase alone and superoxide dismutase in combination with catalase, but not by either superoxide dismutase alone or deferoxamine. These results suggest that among H2O2, OH. and O2.-, only H2O2 causes the removal of haem and the oxidation of oxymyoglobin. Furthermore, the oxyradicals also released 3 microM free iron from oxymyoglobin, which is at least 5-fold less than the 15 nmol loss of oxymyoglobin. The loss of oxymyoglobin also preceded the release of free iron. These results indicate that oxymyoglobin oxidation and haem removal occur before the removal of free iron. Thus myoglobin appears to be highly susceptible to free radical attack, and this may represent yet another mechanism of free radical-mediated cellular injury.

Animals↗
PubMed1989

Animals' rights.

Explore the source record for details and available documents.

Animal Welfare↗
PubMed1989

Response patterns of purified myeloma cells to hematopoietic growth factors.

Tumor cells were isolated from the bone marrow of seven patients with multiple myeloma and from the peripheral blood of three patients with plasma cell leukemia using Ficoll-Hypaque (FH) density sedimentation followed by immune rosette depletion of T, myeloid, monocytoid, and natural killer (NK) cells. Enrichment to greater than or equal to 93% plasma cells was confirmed with Wright's-Giemsa staining, with intracytoplasmic immunoglobulin staining, and with staining using monoclonal antibodies (MoAbs) directed at B, T, myeloid, monocytoid, and myeloma antigens in indirect immunofluorescence assays. Myeloma cells neither proliferated nor secreted Ig in response to G/M-CSF, G-CSF, M-CSF, interleukin-1 alpha (IL-1 alpha), interleukin-1 beta (IL-1 beta), interleukin-2 (IL-2), or interleukin-4 (IL-4). Significant proliferation (SI greater than or equal to 3.0) was induced by interleukin-6 (IL-6) in six of ten patients (SI of 31 and 43 in two cases); and to interleukin-3 (IL-3) and interleukin-5 (IL-5), independently, in two patients each. Peak proliferation to IL-5 or IL-6 and to IL-3 occurred in cells pulsed with 3[H] thymidine at 24 and 48 hours, respectively; and proliferation to combinations of factors did not exceed that noted to IL-6 alone; Ig secretion was not documented under any culture conditions. Three myeloma-derived cell lines similarly studied demonstrated variable responses. The heterogeneity in the in vitro responses of myeloma cells and derived cell lines to exogenous growth factors enhances our understanding of abnormal plasma cell growth and may yield insight into the pathophysiology of plasma cell dyscrasias.

Antigens, Surface↗
PubMed1989

Evaluation of the morantel sustained release trilaminate in the control of parasitic gastroenteritis in first season grazing cattle.

A novel intraruminal bolus developed for the sustained delivery of the anthelmintic morantel tartrate was evaluated in the seasonal control of parasitic gastroenteritis in first season grazing calves. The morantel sustained release trilaminate is a trilaminate sheet consisting of a central lamina of a morantel tartrate/ethylene vinyl acetate matrix coated on both sides with a thin impermeable layer of ethylene vinyl acetate. A symmetrical pattern of circular perforations punched through the device controls the release of morantel. Administration of the trilaminate to calves significantly reduced their faecal egg output compared with untreated controls and thus reduced pasture larval contamination. Clinical parasitic gastroenteritis was prevented in the treated calves and there were significant reductions in their worm burdens compared with the untreated control calves both during and at the end of the grazing season. The control of parasitic gastroenteritis resulted in a significantly greater (P less than 0.0001) weight gain, of 45 kg, by the treated calves.

Animals↗
PubMed1989

A comparison of the physical properties of four prosthetic veneering materials.

Four resin materials used to veneer metal castings were compared by evaluating certain physical properties. Three of the materials were microfilled resins and one was an unfilled resin. Although no material proved to be superior in all of the tests, the microfilled materials were generally better than the unfilled materials. The heat- and pressure- polymerized microfilled material was inferior to the two light-polymerized microfilled materials in three of the physical property tests, superior to them in one test, and proved to be equivalent to them in two tests.

Acrylic Resins↗