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Biomedical subjects

C Wilcox

Publications and source records attributed to C Wilcox.

At least 37 records · Page 2Linked to original sources

Job-sharing: an innovative approach for administration.

A job-sharing arrangement for the Assistant Directors of Physiotherapy at the Royal Jubilee Hospital proved to be an innovative and successful experience demonstrating the feasibility of job-sharing at administrative levels in rehabilitation. Physiotherapy is traditionally a female dominated profession. By the time therapists are most highly skilled and clinically experienced, they have arrived at prime marriage and child-bearing years. Many valuable members are lost to the profession each year as therapists leave the work force to take care of their families, continue their education and participate in recreational activities. Alternative employment opportunities are needed to retain and return therapists to the work force. Convenience of work time is often important. Financial expectations may become a secondary consideration. A search of the literature revealed that while job-sharing has much to recommend it, it is not yet generally accepted in most health professional situations. A few anecdotal references described job-sharing in nursing. An industry-wide literature search revealed few references to the application of job-sharing at administrative levels.

British Columbia↗

A study of radiologists viewing multiple computed tomography examinations using an eyetracking device.

Understanding the scan patterns radiologists use to view medical images is critical to the design of image viewing devices. In this study, an eyetracker, a device for recording eye and head movement, was used to determine the scan patterns during the interpretation of single and multiple computed tomographic (CT) examinations presented on a four-over-four viewbox. CT examinations were used because they represent complex viewing situations. In two separate studies, radiologists viewed patient folders containing single or multiple CT chest examinations and dictated a report. Eye movement was recorded with an eyetracker and video camera. After mounting the films in order, radiologists generally started with a sequential scan through the entire examination, followed by careful viewing of two to four clusters of three to six images, followed by dictation. These results indicate that a well designed radiology workstation should provide an image index, sufficient display area to simultaneously view 10 or more images, random and sequential movement through the examination, image comparison, and image marking.

Ergonomics↗

Preparation and characterization of monoclonal antibodies against the fifth component of rabbit complement (C5).

By immunizing mice genetically deficient in C5 we were able to obtain a group of monoclonal antibodies to rabbit C5 that cross-react with C5 from a wide variety of mammalian sera, including mouse. The specificity of the monoclonal antibodies was against native C5 and C5b but not C5a. The antibodies strongly inhibit the expression of C5 hemolytic activity. We suggest that these monoclonal antibodies will be useful for studying C5 as well as providing a way to selectively deplete C5 from plasma in vitro or in vivo.

Animals↗

Acylation of proteins with myristic acid occurs cotranslationally.

Several proteins of viral and cellular origin are acylated with myristic acid early during their biogenesis. To investigate the possibility that myristylation occurred cotranslationally, the BC3H1 muscle cell line, which contains a broad array of myristylated proteins, was pulse-labeled with [3H]myristic acid. Nascent polypeptide chains covalently associated with transfer RNA were isolated subsequently by ion-exchange chromatography. [3H]Myristate was attached to nascent chains through an amide linkage and was identified by thin-layer chromatography after its release from nascent chains by acid methanolysis. Inhibition of cellular protein synthesis with puromycin resulted in cessation of [3H]myristate-labeling of nascent chains, in agreement with the dependence of this modification on protein synthesis in vivo. These data represent a direct demonstration that myristylation of proteins is a cotranslational modification.

Acylation↗

Regulation of myogenic differentiation by type beta transforming growth factor.

Type beta transforming growth factor (TGF beta) has been shown to be both a positive and negative regulator of cellular proliferation and differentiation. The effects of TGF beta also are cell-type specific and appear to be modulated by other growth factors. In the present study, we examined the potential of TGF beta for control of myogenic differentiation. In mouse C-2 myoblasts, TGF beta inhibited fusion and prevented expression of the muscle-specific gene products, creatine kinase and acetylcholine receptor. Differentiation of the nonfusing muscle cell line, BC2Hl, was also inhibited by TGF beta in a dose-dependent manner (ID50 approximately 0.5 ng/ml). TGF beta was not mitogenic for either muscle cell line, indicating that its inhibitory effects do not require cell proliferation. Inhibition of differentiation required the continual presence of TGF beta in the culture media. Removal of TGF beta led to rapid appearance of muscle proteins, which indicates that intracellular signals generated by TGF beta are highly transient and require continuous occupancy of the TGF beta receptor. Northern blot hybridization analysis using a muscle creatine kinase cDNA probe indicated that TGF beta inhibited differentiation at the level of muscle-specific mRNA accumulation. These results provide the first demonstration that TGF beta is a potent regulator of myogenic differentiation and suggest that TGF beta may play an important role in the control of tissue-specific gene expression during development.

Animals↗

A comparison of fluoxetine, imipramine, and placebo in patients with major depressive disorder.

The efficacy and safety of fluoxetine were compared with those of imipramine and of placebo in a 6-week randomized double-blind parallel study of patients with major depressive illness. Mean values for all efficacy measurements were improved over baseline with fluoxetine and imipramine treatment (p less than .001). More fluoxetine patients completed the study than did imipramine or placebo patients. Predominant adverse experiences reported by imipramine patients were dry mouth and dizziness/lightheadedness. Predominant adverse experiences reported by fluoxetine patients were drowsiness/sedation and excessive sweating. In a subsequent 48-week open-label study, the predominant adverse experience in the fluoxetine group was excessive sweating and in the imipramine group was still dry mouth. In this study, fluoxetine relieved the symptoms of major depressive illness effectively and significantly better than placebo and was better tolerated than imipramine.

Adult↗

The pressor actions of noradrenaline, angiotensin II and saralasin in chronic autonomic failure treated with fludrocortisone.

1 Treatment of postural hypotension due to chronic autonomic failure with fludrocortisone increased the pressor sensitivity to intravenous noradrenaline. Fludrocortisone increased the blood pressure in the standing but not the lying position. These effects of fludrocortisone may be the result of increased sensitivity of vascular receptors to noradrenaline. 2 The pressor action of angiotensin II, to which patients were supersensitive, may have involved the stimulation of alpha-adrenoceptors since it was partially antagonised by phentolamine. 3 Saralasin had a marked, paradoxical, pressor effect. This may have been mediated by vascular alpha-adrenoceptors because log dose-response curves of saralasin-induced increases in systolic pressure were shifted to the right in a parallel fashion after phentolamine. 4 Fludrocortisone treatment increased the pressor sensitivity to intravenous saralasin but not to angiotensin-II.

Aged↗

Susceptibility of "enterobacteria" to aminoglycoside antibiotics: comparisons with tetracyclines, polymyxins, chloramphenicol, and spectinomycin.

Strains of enterobacteria, including common, aerobic, pathogenic gram-negative bacilli, and enterococci were tested for susceptibility to 11 aminoglycoside antibiotics by a twofold agar-dilution method with an inocula replicator. For comparison, similar tests were done with seven tetracycline analogues, two polymyxins, chloramphenicol, and spectinomycin. Tobramycin compared favorably with the more active aminoglycosides, with some exceptions related to individual strains of species. The tetracyclines and chloramphenicol were generally less active than the more active aminoglycosides. The polymyxins were as active or more active against most species of gram-negative rods but were essentially inactive against Proteus, Providencia, and many strains of Enterobacter.

Acinetobacter↗

Susceptibility of "enterobacteria" to penicillins, cephalosporins, lincomycins, erythromycin, and rifampin.

Agar dilution tests for susceptibility of gram-negative rods and enterococci were done with a number of penicillins, cephalosporins, lincomycin analogues, erythromycin, and rifampin. Many in the first three categories were investigational drugs. All were generally less active than aminoglycoside and tetracycline antibiotics against gram-negative rods and more active against enterococci. Cephalosporins as a group were more active than penicillins against Klebsiella pneumoniae and Escherichia coli and less active enterococci. Both groups were equally active against Enterobacter, Proteus, and Providencia but inactive against most strains of Serratia and all strains of Pseudomonas; however, ticarcillin, carbenicillin, and BL-1654 were active against most strains of Pseudomonas. Penicillins and cephalosporins were more active against Proteus mirabilis than against indole-positive Proteus. Lincomycins had little or no activity against gram-negative rods but were moderately active against enterococci. Erythromycin was more active than the lincomycins, but rifampin was much more active than either of these types of drug. Of the penicillins, ticarcillin, carbenicillin, and BL-P1654 were the most active against gram-negative rods, whereas BL-P1654, amoxicillin, and ampicillin were the most active against enterococci. The penicillinase-resistant penicillins, cyclacillin, and penicillin V were essentially inactive against gram-negative rods. Of the cephalosporins tested, cephanone and cefamandole were the most active against most gram-negative rods, whereas cephaloridine and cephacetrile were the most active against enterococci. The least active of the cephalosporins against most species were cephradine, cephalexin, and cephapirin, but cefoxitin was the least active against enterococci.

Acinetobacter↗

Susceptibility of recently isolated bacteria to amikacin in vitro: comparisons with four other aminoglycoside antibiotics.

In vitro tests for susceptibility to amikacin and to four other aminoglycoside antibiotics were carried out with strains of many bacterial species by use of an agar dilution method and an inocula replicator. In general, amikacin was as active as or more active against most of the organims than kanamycin, neomycin, and streptomycin; in particular, amikacin was active against strains resistant to one or more of these three antibiotics. Amikacin was more active than gentamicin against strains of Nocardia asteroides and Providencia stuartii and also against gentamicin-resistant strains of some other gram-negative bacilli, notably Serratia marcescens. However, gentamicin was more active than amikacin against most of the other gram-positive and gram-negative bacteria that were tested. In comparative tests of four media, minimal inhibitory concentrations MICs) were greater in tests with Mueller-Hinton agar, and generally somewhat lower in those with heart infusion agar, than in tests with trypticase soy agar and nutrient agar. Inocula of a 1:1,000 dilution of culture generally gave MICs lower than those obtained with undiluted cultures; the differences were small with enterococci, but they were greater with amikacin than with gentamicin in tests on strains of Klebsiella pneumoniae. These findings generally confirm those previously reported by others.

Amikacin↗

Susceptibility of beta-hemolytic streptococci to 65 antibacterial agents.

Tests for susceptibility of 29 group A, 4 group C, and 2 group G strains of beta-hemolytic streptococci to 63 antibiotics and to trimethoprim and sulfamethoxazole, singly and combined in a ratio of 1:16, were carried out in vitro. All strains tested were moderately or highly susceptible to all the antibiotics used except those belonging to the aminoglycoside and polymyxin groups. A few were also resistant to the tetracyclines and to sulfamethoxazole alone. Comparisons with results obtained in previous years indicate that, except for the tetracyclines and sulfonamides, there has been no change in the susceptibility of beta-hemolytic streptococci to the most important and useful antibiotics, particularly penicillin.

Aminoglycosides↗

Susceptibility of pneumococci and Haemophilus influenzae to antibacterial agents.

Strains of Diplococcus pneumoniae and Haemophilus influenzae were tested for susceptibility to numerous antibiotics by a twofold agar dilution method using an inocula replicator. Undiluted, fully grown broth cultures were used as inocula for both species, and cultures of pneumococci diluted 1:1,000 were also tested. The antibiotics included most of those in common use in the United States as well as some chemical modifications recently approved and others that are under investigation. The most striking aspect of the results was the marked susceptibility of the pneumococci to all the antibiotics tested except the polymyxins and most of the aminoglycoside antibiotics, although some new aminoglycosides were active in quite low concentrations. Some of the strains of pneumococci were of decreased susceptibility to penicillin G (minimal inhibitory concentrations, 0.2 to 0.4 mug/ml), but none were tetracycline resistant, although such strains had been reported previously from this laboratory. The strains of H. influenzae, which were all serologically nontypable, exhibited different patterns of susceptibility to the groups of antibiotics and to the individual chemically related ones. None of these strains (isolated early in 1972) were ampicillin resistant. The most active agents against H. influenzae were: carbenicillin and ampicillin, analogues related to each of them, rifampin, chloramphenicol, and the polymyxins. However, the tetracycline analogues other than tetracycline, some aminoglycosides, notably tobramycin, kanamycin, gentamicin, and verdamicin, erythromycin, and some new lincomycin analogues were also active in low concentrations. Trimethoprim alone was highly active, and in combination with sulfamethoxazole it was even more active and synergistic against strains of both D. pneumoniae and H. influenzae.

Aminoglycosides↗

Synergy of mecillinam (FL1060) with penicillins and cephalosporins against Proteus and Klebsiella, with observations on combinations with other antibiotics and against other bacterial species.

Thirty-five strains each of Klebsiella and Proteus were tested for susceptibility to mecillinam alone and in combination with ampicillin, carbenicillin, cephalothin, and cefazolin. Antibiotics were considered to be synergistic when there was a >/=fourfold reduction in minimum inhibiting concentration of both antibiotics in the combination as compared with that of each antibiotic alone. Synergy of mecillinam with ampicillin, carbenicillin, cephalothin, and cefazolin was demonstrated against 2, 3, 7, and 8 of the 35 strains of Klebsiella and against 14, 14, 19, and 24 of the 35 strains of Proteus, respectively. Synergy against the isolates of Proteus was related to species, whereas against Klebsiella it was related to susceptibility of the isolates to mecillinam. Tests of combinations of mecillinam with other antibiotics on the same and different species indicated that synergy was related to the antibiotic, the species, and the strains of organisms tested.

Anti-Bacterial Agents↗