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Biomedical subjects

C Field

Publications and source records attributed to C Field.

At least 37 records · Page 2Linked to original sources
PubMed1997

The effects of buspirone on perceived exertion and time to fatigue in man.

Male subjects exercised at 80% maximal rate of O2 uptake (VO2,max) following oral administration of either placebo or the partial 5-HT1A agonist buspirone (45 mg), using a paired design. Ratings of perceived exertion were higher following buspirone and time to volitional fatigue (median and inter-quartile range) fell significantly by approximately a third from 26 min (24-30 min) on placebo to 16 min (11-19 min) following buspirone. Serum prolactin was significantly elevated following buspirone administration, indicating increased hypothalamic 5-HT1A receptor stimulation. There were no significant differences in blood lactate or serum glucose between the trials. This study supports the possible central modulation of exercise tolerance by serotonergic pathways, although a role for dopamine cannot be excluded.

Adult↗
PubMed1995

Scintigraphic evaluation of the haemopoietic bone marrow using a 99mTc-anti-granulocyte antibody: a validation study with 52Fe.

To specify the validity of bone marrow scanning using a monoclonal anti-granulocyte antibody labelled with 99mTc (BW 250/183) for the functional assessment of haemopoiesis, we compared this method with 52Fe scan in 16 patients with haematological disorders. The examinations were performed using a rectilinear whole-body scanner and the distribution of the two tracers was assessed visually and quantitatively in anatomical bone marrow segments, the spleen and liver. Qualitative comparison showed concordance in the bone marrow distribution of the two tracers in 83% of the segments. Discrepancies were found in six patients with hypoplastic or aplastic marrow. The spleen was visualized in all cases with the 99mTc-Moab, including nine patients without splenic haemopoiesis (i.e. without spleen uptake of 52Fe). The uptake of the two tracers, quantified in bone marrow segments and the spleen, correlated well (P < 0.001), but not in the liver (NS). The correlation between the uptake values for each patient was excellent, except in cases of aplastic bone marrow. In conclusion, bone marrow scanning using a 99mTc labelled anti-granulocyte monoclonal antibody enables functional evaluation of the distribution of haemopoiesis. Limitations include the evaluation of bone marrow aplasia and identification of splenic haemopoiesis, for which 52Fe remains the tracer of choice.

Adolescent↗
PubMed1992

The incidence of total hip replacement in orthognathic surgery patients receiving short-term steroid therapy.

It is well known that long-term corticosteroid therapy can lead to avascular necrosis of the femoral head. There is suspicion among orthopedic surgeons that short-term, high-dose steroid use poses similar risks. The records of 2,773 patients (1,497 who had total hip replacement and 1,276 who had orthognathic surgery) were retrospectively reviewed. No hip replacements had been done in the orthognathic surgery group and none of the patients in the total hip replacement group had undergone orthognathic surgery. The use of short-course, systemic corticosteroids to reduce postoperative swelling in orthognathic surgery did not seem to cause avascular necrosis of the femoral head.

Adrenal Cortex Hormones↗
PubMed1990

Effects of enflurane on visual evoked potentials in humans.

Effects of enflurane on visual evoked potentials (VEP) were studied in eight healthy female patients. Control VEP were recorded from the occipital electrode (OZ-CZ), and prominent negative (N70) and positive (P100) peaks were observed following flash light stimulation. After induction of anaesthesia with thiopentone, VEP were recorded at expired concentrations of 1.2, 1.8, 2.4 and 2.7% of enflurane in 100% oxygen. The amplitude of the P100 was decreased and the latency of the N70 was increased significantly from the control with all concentrations of enflurane. No significant difference was found between different concentrations of enflurane. The latency of the P100 was increased significantly only at concentrations above MAC and at 2.7% when it was significantly longer than those at 1.2 and 1.8%. We conclude that VEP are altered significantly with enflurane in clinically used concentrations.

Adult↗
PubMed1989

Visual evoked potentials during thiopentone-fentanyl-nitrous oxide anaesthesia in humans.

Visual evoked potentials (VEP) during thiopentone-fentanyl-nitrous oxide anaesthesia were studied in 15 healthy patients undergoing non-neurosurgical procedures. The VEP was recorded before and at 1 and 2 min after induction of anaesthesia with 5-6 mg.kg-1 of thiopentone. After recording the 1 and 2 min VEPs, anaesthesia was maintained with a fentanyl-nitrous oxide-oxygen combination, and further recordings were made at 5, 10, 15 and 20 min after induction. The 1 and 2 min VEPs showed a marked decrease in the amplitudes. Latencies were increased. The amplitudes gradually returned to the control level at 15 min, while the latencies remained increased throughout the study period. In conclusion, thiopentone should be avoided during the critical period of VEP recording. Once it is given, at least 15 min should elapse before an appropriate interpretation of the VEP can be made. Thiopentone-fentanyl-nitrous oxide anaesthesia slightly increases the latencies of the VEP. These effects should be considered in the interpretation of the VEP when thiopentone-fentanyl-nitrous oxide anaesthesia is used.

Adult↗
PubMed1988

SEC7 encodes an unusual, high molecular weight protein required for membrane traffic from the yeast Golgi apparatus.

Saccharomyces cerevisiae with mutations at the sec7 locus are pleiotropically deficient in protein transport within the Golgi apparatus and proliferate a large array of Golgi cisternae at a restrictive growth temperature (37 degrees C). The SEC7 gene and its product (Sec7p) have been evaluated by molecular cloning and sequence analysis. Two genes that allow sec7 mutant cells to grow at 37 degrees C are represented in wild-type yeast DNA libraries. A single copy of the authentic SEC7 gene permits growth of mutant cells, whereas the other gene suppresses growth deficiency only when expressed from a multicopy plasmid. The SEC7 gene is contained on a 8.4-kilobase pair SphI restriction fragment, portions of which hybridize to a single 6-kilobase pair mRNA. The gene is essential for yeast vegetative growth. DNA sequence analysis of this region detects a single open reading frame with the potential to encode a 2008-amino acid-long hydrophilic protein of 230 kDa. Putative Sec7p contains an unusual, highly charged acidic domain of 125 amino acids with 29% glutamate, 18% aspartate, and 21% serine. Within this region, stretches of 14 consecutive glutamate residues and 13 consecutive glutamates/aspartates are predicted. This domain in Sec7p may serve a structural role to interact with lipids or proteins on the cytoplasmic surface of the Golgi apparatus.

Amino Acid Sequence↗
PubMed1987

An audit of electroconvulsive therapy.

OBJECTIVE: To audit five years experience with electroconvulsive therapy (ECT). METHOD: Retrospectively audit the case records of all patients receiving ECT from 1981 to 1985. This enabled us to compare our clinical practise with published guidelines for optimal use of ECT. RESULTS: Review 486 courses of ECT yielded a total of 3936 treatments. The audit identified several areas of clinical practise which do not comply with recommended standards for ECT.

Data Collection↗
PubMed1986

GAL2 codes for a membrane-bound subunit of the galactose permease in Saccharomyces cerevisiae.

The gene encoding the galactose permease of Saccharomyces cerevisiae (GAL2) was cloned. The clone restores galactose permease activity to gal2 yeasts and is regulated by galactose in a manner similar to other GAL gene products (GAL1, -7, and -10). Experiments with temperature-conditional secretory mutants indicated that transport of the GAL2 gene product to the cell surface requires a functional secretory pathway. In addition, gene fusions were constructed between the GAL2 gene and the Escherichia coli lacZ gene. The GAL2-lacZ gene fusions code for galactose-regulated beta-galactosidase activity in yeasts. The beta-galactosidase activity was found to be membrane bound.

Biological Transport↗
PubMed1984

Yeast secretory mutants that block the formation of active cell surface enzymes.

Yeast cells secrete a variety of glycosylated proteins. At least two of these proteins, invertase and acid phosphatase, fail to be secreted in a new class of mutants that are temperature-sensitive for growth. Unlike the yeast secretory mutants previously described (class A sec mutants; Novick, P., C. Field, and R. Schekman, 1980, Cell., 21:205-420), class B sec mutants (sec 53, sec 59) fail to produce active secretory enzymes at the restrictive temperature (37 degrees C). sec 53 and sec 59 appear to be defective in reactions associated with the endoplasmic reticulum. Although protein synthesis continues at a nearly normal rate for 2 h at 37 degrees C, incorporation of [3H]mannose into glycoprotein is reduced. Immunoreactive polypeptide forms of invertase accumulate within the cell which have mobilities on SDS PAGE consistent with incomplete glycosylation: sec 53 produces little or no glycosylated invertase, and sec 59 accumulates forms containing 0-3 of the 9-10 N-linked oligosaccharide chains that are normally added to the protein. In addition to secreted enzymes, maturation of the vacuolar glycoprotein carboxypeptidase Y, incorporation of the plasma membrane sulfate permease activity, and secretion of the major cell wall proteins are blocked at 37 degrees C.

Acid Phosphatase↗