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Biomedical subjects

J Campbell

Publications and source records attributed to J Campbell.

At least 343 records · Page 19Linked to original sources
PubMed1984

Legionella sainthelensi: a new species of Legionella isolated from water near Mt. St. Helens.

Six strains of a new species, Legionella sainthelensi, were isolated from freshwater in areas affected by the volcanic eruptions of Mt. St. Helens in the state of Washington. Strains of L. sainthelensi are culturally and biochemically similar to other legionellae. They grow on buffered charcoal yeast agar but not on media that lack cysteine. They are gram-negative, nonsporeforming, motile rods that are positive in reactions for catalase, oxidase, gelatin liquefaction, and beta-lactamase. They are negative in reactions for urease, hydrolysis of hippurate, reduction of nitrates, fermentation of glucose, and blue-white autofluorescence. Their cell wall fatty acid composition is qualitatively similar to those of other legionellae, with 50 to 62% branched-chain fatty acids. They contain the isobranched-chain 14- and 16-carbon acids and anteisobranched-chain 15- and 17-carbon acids and relatively large amounts of straight-chain 16-carbon acid. All strains of L. sainthelensi contain approximately equal amounts of ubiquinones Q9, Q10, Q11, and Q12, a pattern similar to those of Legionella bozemanii, Legionella dumoffi, and Legionella longbeachae. Serological cross-reactions were observed between L. sainthelensi, both serogroups of L. longbeachae, and Legionella oakridgensis. Three strains of L. sainthelensi were greater than 90% related by DNA hybridization. The type strain of L. sainthelensi, Mt. St. Helens 4, was 36% related to the type strain of L. longbeachae and 3 to 14% related to the other nine described Legionella species.

Disasters↗
PubMed1984

Endothelial seeding of Dacron and polytetrafluoroethylene grafts: the cellular events of healing.

To detect cellular differences in the healing of polytetrafluoroethylene (e-PTFE) and Dacron grafts up to 7 months after implantation, we studied 108 aortic graft interpositions in dogs. Each prosthesis was alternately prepared by endothelial seeding or by an unseeded control method. The grafts were perfusion fixed and studied with light, scanning, and transmission electron microscopy at intervals from before to 221 days after implantation. Seeding resulted in the development of an extensive endothelial flow surface in two out of three of the e-PTFE and none out of four of the Dacron grafts by 10 days after implantation (p = 0.053). After 30 days a microfibrillar subendothelial matrix ranging from 5 to 11 mu formed in all but three grafts with endothelial coverage. The inner capsule of mature Dacron grafts was significantly thicker (169 +/- 143 mu) than in e-PTFE grafts (22 +/- 32 mu; p = 0.002). Seeded and unseeded Dacron grafts had predominantly fibroblasts in the outer capsule of the graft by 10 days. Surface endothelium, vasa vasorum, fibroblasts, and myointimal cells appeared in the inner capsule between 10 and 30 days after implantation. In Dacron grafts, fibroblasts and myointimal cells predominated in the inner capsule at 30 days, with smooth muscle cells not being definitely identifiable until after 150 days. Neither fibroblasts nor myointimal cells were common (present but sparse in one of four e-PTFE grafts) at 30 days, and transmural vasa vasorum were never seen. The seeded endothelial cells migrated rapidly from the sites of initial adhesion near the e-PTFE onto the flow surface. Only one of four of the unseeded e-PTFE grafts had surface endothelium after 30 days, and only moderate coverage developed during 180 days. We conclude that endothelial healing is more rapid in seeded e-PTFE grafts than in seeded Dacron grafts and occurs by a different mechanism.

Animals↗
PubMed1984

Phase I-II trial of high-dose calcium leucovorin and 5-fluorouracil in advanced colorectal cancer.

Twenty-six patients with metastatic colorectal adenocarcinoma were entered into a Phase I-II study of 5-fluorouracil (5-FUra)-high-dose leucovorin (CF). The starting dose of 5-FUra was 300 mg/sq m with escalation to 750 mg/sq m/week in 6 doses given by rapid i.v. injection midway during a 2-hr infusion of CF, 500 mg/sq m. Partial responses were seen in 9 of 23 patients (6 of 12 who had had previous 5-FUra). Complete normalization of liver enzymes was seen in two of these patients. Side effects were seen sporadically with 5-FUra doses up to 600 mg/sq m. At a 600-mg/sq m 5-FUra dose, 8 of 18 patients had diarrhea, and 2 of 18 had white blood cell counts less than 3000/microliter. At a 750-mg/sq m dose of 5-FUra, 6 of 11 patients had severe diarrhea and 6 of 11 had white blood cell counts less than 3000/microliter. Other toxicities were mild conjunctivitis and lacrimation, thinning of the nails, and alopecia. In bioavailability studies of CF p.o., no plasma CF could be detected. After CF i.v., mean plasma peak was 111.3 +/- 40.3 (S.D.) microM. 5-FUra-CF appears to be effective in patients clinically resistant to 5-FUra. This study is being extended to randomized trial of 5-FUra-CF versus 5-FUra alone.

Adult↗
PubMed1984

[Ischemic muscular pain. II. Its evaluation by the McGill Pain Questionnaire in the repeated performance of an experimental test].

Muscular ischaemic pain experienced by 11 healthy subjects during the performance of an experimental test repeated on three succesive occasions was evaluated by the scoring and analysis of the McGill Pain Questionnaire, completed by the individual after each test. A statistically significant reduction in three scores: Number of Words Chosen, Pain Rating Index Total and Pain Rating Index Sensory was observed between the first and third tests. Indices related to the Affective and Evaluative aspects of pain did not exhibit significant variations. Possible interpretations for these findings, especially those related to the nature of the experimental test and the previously reported increase in Pain Tolerance from the first to the third test in this group are discussed. These results stress the need of using adequate control groups when analgesic measures are evaluated by experimental methods.

Humans↗
PubMed1983

Comparative cost of walking in young and old adults.

Normative data that summarize the energy requirements and gait characteristics of level outdoor walking were determined in 111 normal subjects between the ages of 20 and 80 years. Subjects were divided into two age groups: young adults (20-59 years) and senior subjects (60-80 years). The mean rate of oxygen consumption for young adults and senior subjects did not significantly differ, averaging 11.9 ml/kg-min for both groups. The data on heart rate paralleled the findings on oxygen consumption, averaging 100 and 103 beats/min, respectively. The net oxygen cost per meter walked for senior subjects, 0.16 ml/kg-m, was significantly greater (p less than 0.0005) than the value for young adults, 0.15 ml/kg-m, due to a decline in the average walking speed. The average gait velocity for senior subjects, 73 m/min, was statistically significantly less (p less than 0.0005) than the values for the younger adults, 80 m/min.

Adult↗
PubMed1983

The prevalence of enterococci in the dental plaque of chronic hospital patients.

Enterococci have caused 2 of 3 reported cases of infective endocarditis following dental treatment of patients receiving haemodialysis. Since this could indicate an increased carriage rate of enterococci in the mouths of such patients, the prevalence of enterococci in dental plaque was compared in four groups of subjects, chronic dialysis patients, chronic cardiac patients, medical staff and dental hospital out-patients. The isolation of enterococci was significantly increased in both chronic patient groups and this may be related to their greater exposure to antibiotic therapy.

Adult↗
PubMed1983

The effects of endogenous phospholipase A2 activation on beta adrenoceptor function in cardiac cells.

The effects of endogenous phospholipase A2 activation by melittin on components of the beta adrenoceptor linked adenylate cyclase system were examined in cultured cardiac cells. Exposure of cardiac cells for one hour to melittin concentrations ranging from 0.125 microgram/ml to 5.0 micrograms/ml induced a concentration dependent hydrolysis of radioactively labelled phospholipids and loss of lysophospholipids from the cell membrane. Melittin concentrations of 2.5 micrograms/ml or greater markedly attenuated the isoprenaline induced rise in cyclic AMP. In vitro studies using cell homogenates suggest that phospholipase A2 activation by the higher concentration of melittin (5 micrograms/ml) partially uncoupled the beta adrenoceptor from adenylate cyclase. Beta adrenoceptor number estimated by 125I-iodohydroxybenzylpindolol specific binding as well as the affinity of isoprenaline for these binding sites were unaffected by melittin pre-exposure. The percentage stimulation of adenylate cyclase by sodium fluoride or guanylylimidodi-phosphate was not significantly affected by activation of endogenous phospholipase A2. Phosphodiesterase activity in the soluble fraction of cell homogenates increased marginally (9%, P = 0.05) in cells exposed to melittin. These results suggest that activation of endogenous phospholipase A2 within the sarcolemma can modulate the activity of the beta adrenoceptor linked adenylate cyclase system of intact cardiac cells. The reduced beta adrenoceptor responsiveness of the cells appears to be primarily due to an alteration in coupling between the beta adrenoceptor and the guanine nucleotide binding protein components of the adenylate cyclase system and not between the latter and the catalytic subunit.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1983

Serological studies of Australian and Papua New Guinean cattle and Australian sheep for the presence of antibodies against bluetongue group viruses.

Following isolation of a virus (CSIRO19) from insects in Australia and its identification as bluetongue virus serotype 20 (BTV20), a nationwide survey of antibodies in cattle and sheep sera was undertaken. Initial studies using the serum neutralization (SN) test showed that the distribution of BTV20 antibodies in cattle was confined to the northern part of Australia. Group-reactive antibody tests (agar gel diffusion precipitin, AGDP, and complement-fixation, CF) showed group-reactive cattle sera south of the BTV20 zone (northern Australia), and southwards from Queensland to New South Wales. Very few group-reactive sheep sera (45 out of 16213) were found and these were of doubtful epidemiological significance. Some of these BTV group-reactive, BTV20-negative, sera were tested in SN tests against BTV1 to 17 and Ibaraki (IBA) virus. The results indicated that BTV1, or a closely related orbivirus, was active in cattle in Queensland, northern Western Australia, and New South Wales, and that antibody to BTV15 was present in some of the cattle sera in northern Western Australia and the Northern Territory. Antibody to IBA virus was present in some cattle sera in Queensland, northern Western Australia and New South Wales. SN antibody titres greater than or equal to 60 were also found to a number of other BTV serotypes in cattle sera in northern Western Australia and Queensland (principally, BTV2 and BTV7). Low level reactions were commonly observed against these and a number of other BTV serotypes, often in the same serum samples. Further, 22% of the group-reactive cattle sera did not react with any of the viruses in the SN tests. Such results were difficult to interpret in terms of known Australian BTV or BTV-related isolates.

Animals↗
PubMed1983

Energy cost of walking in normal children and teenagers.

Oxygen consumption during free level walking was determined in 114 children and teenaged subjects between the ages of 6 and 19 years and compared with a group of 47 normal adults. Subjects were divided into two age groups: children (6-12 years) and adolescents (13-19 years). The mean rate of oxygen uptake for children was significantly greater, 15.3 ml/kg/min, than the value for teenaged subjects, 12.9 ml/kg/min. The oxygen cost to walk a unit distance (meter) was higher in children than adolescent subjects. The mean values averaged .22 ml/kg/min and .18 ml/kg/min respectively. The data on heart rate paralleled the findings on oxygen consumption. The mean heart rate for children, 114 beats per minute (bpm), was significantly higher than the mean values for adolescent subjects, 97 bpm.

Adolescent↗
PubMed1983

Energy cost of walking and of wheelchair propulsion by children with myelodysplasia: comparison with normal children.

The oxygen consumption of 15 myelodysplastic children during walking and propelling a wheelchair was studied. In comparison to normal children, they walked more slower and consumed more oxygen per meter, but had a similar rate of oxygen consumption. A swing-through gait pattern was 33 per cent more energy-efficient than a four-point gait pattern for these children. Wheelchair propulsion produced velocities and energy efficiencies similar to normal children walking. Oxygen consumption and velocity measurements were found to be significantly related to the clinical factors of level of lesion and strength of hip and knee extension. Regression lines and equations are presented to permit prediction of energy cost and efficiency from heart-rate data of myelodysplastic children.

Child↗