PubMed Health⌕ Search

Biomedical subjects

J S Lloyd

Publications and source records attributed to J S Lloyd.

At least 19 recordsLinked to original sources
PubMed1999

Heterologous expression of alkene monooxygenase from Rhodococcus rhodochrous B-276.

Alkene monooxygenase (AMO) from Rhodococcus rhodochrous (formerly Nocardia corallina) B-276 is a three-component enzyme system encoded by the four-gene operon amoABCD. AMO catalyses the stereoselective epoxygenation of aliphatic alkenes, yielding primarily R enantiomers. The presumed site of alkene oxygenation is a dinuclear iron centre similar to that in the soluble methane monooxygenases of methanotrophic bacteria, to which AMO exhibits a significant degree of amino acid sequence identity. The AMO complex was not expressed in Escherichia coli, at least partly because that host did not produce all of the AMO polypeptides. Expression of AMO was achieved in Streptomyces lividans by cloning the AMO genes into the thiostrepton-inducible expression plasmid pIJ6021. No background of AMO activity was detected in S. lividans cells without amoABCD and expression of AMO activity, at a level comparable to that from wild-type R. rhodochrous B-276, coincided with appearance of the AMO subunits. Recombinant AMO activity in cell-free extracts of S. lividans was stimulated by the addition of NADH and produced R-epoxypropane with comparable enantiomeric excess to AMO purified from the original organism. Although the whole AMO complex could not be expressed in E. coli, the functional coupling protein (AmoB) and reductase (AmoD) were expressed individually in E. coli as fusions with glutathione S-transferase. The expression systems described here now allow structure/function studies on AMO to be carried out by site-directed mutagenesis.

Base Sequence↗
PubMed1999

Auto-disable syringes for immunization: issues in technology transfer.

WHO and its partners recommend the use of auto-disable syringes, "bundled" with the supply of vaccines when donor dollars are used, in all mass immunization campaigns, and also strongly advocate their use in routine immunization programmes. Because of the relatively high price of auto-disable syringes, WHO's Technical Network for Logistics in Health recommends that activities be initiated to encourage the transfer of production technology for these syringes as a means of promoting their use and enhancing access to the technology. The present article examines factors influencing technology transfer, including feasibility, corporate interest, cost, quality assurance, intellectual property considerations, and probable time frames for implementation. Technology transfer activities are likely to be complex and difficult, and may not result in lower prices for syringes. Guidelines are offered on technology transfer initiatives for auto-disable syringes to ensure the quality of the product, the reliability of the supply, and the feasibility of the technology transfer activity itself.

Disposable Equipment↗
PubMed1997

Inactivation of the regulatory protein B of soluble methane monooxygenase from Methylococcus capsulatus (Bath) by proteolysis can be overcome by a Gly to Gln modification.

The regulatory protein B of soluble methane monooxygenase (sMMO) from Methylococcus capsulatus (Bath), exists as a mixture of the full-length active form and truncated forms, B' and B". Electrospray ionisation mass spectrometry (ESI-MS) was used to identify a cleavage site between Met12 and Gly13, such that 12 amino acids were lost from the N-terminus of protein B. This truncate was designated B' and molecular masses were assigned to proteins B and B' of 15,852.6+/-0.4 Da and 14,629.5+/-0.3 Da, respectively. A cleavage site between Gln29 and Val30 was also identified such that 29 amino acids were lost from the N-terminus of protein B. This truncate was designated B" and had a molecular mass of 12,709.93+/-0.02 Da. Proteins B' and B" were found to be inactive in the sMMO system. Addition of protease inhibitors or the heterologous expression of protein B in various strains of lon-deficient or ompT-deficient Escherichia coli, did not inhibit B' formation. Expression of protein B as a glutathione S-transferase fusion protein and subsequent purification of protein B from E. coli using affinity chromatography resulted in preparations of protein B with higher enzyme activities than that of wild-type protein B. However, ESI-MS confirmed that protein B' was still present. Alteration of the Met12-Gly13 cleavage site to Met12-Gln13 revealed that the stability of G13Q at 20 degrees C and 37 degrees C was higher than that of wild-type preparations. ESI-MS indicated that protein B' was absent and could only be identified after prolonged incubation at room temperature. The amount of active protein B present in the cell may be controlled by protein B cleavage, thereby regulating electron transfer. Alternatively, it may allow protein B to maintain a certain conformation necessary for enzyme activity and this may control the activity of sMMO in response to the supply of methane to the cell.

Amino Acid Sequence↗
PubMed1996

Developmental transitions in the myosin heavy chain phenotype of human respiratory muscle.

We studied the expression of myosin heavy chain (MHC) isoforms in the costal diaphragm (DIA) and the genioglossus (GG) muscles from 16 to 42 weeks gestation in the human using Western blotting techniques. Embryonic/neonatal MHC (MHCemb/neo) was the predominant isoform expressed in the DIA and GG at 16-24 weeks gestation. Subsequently, MHCemb/neo expression declined and the expression of MHCslow and MHC2A increased. At term, the DIA MHC phenotype was a composite of MHCemb/neo (15% of the total MHC complement), MHCslow (32%), MHC2A (47%), and MHC2B (6%); whereas, the GG was largely comprised of MHC2A (74%). We conclude that human DIA and GG demonstrate temporally dependent changes in MHC expression during gestation- and muscle-specific MHC phenotypes as they approach term.

Diaphragm↗
PubMed1996

Bringing reality to the job hunt process. Interview by Barbara J. Linney.

A substantial percentage of the positions that open in medical management are filled through the use of recruitment firms. This is especially true of more senior positions, but it applies across the full spectrum of openings. If the working arrangement between the recruitment firm and the potential candidate is to be effective, certain key ingredients are necessary. The author interviewed a selection of principals of recruitment firms that operate extensively or exclusively in the medical management sector of executive recruitment. What she discovered about their "wish lists" for candidates' characteristics and levels of job hunting sophistication are summarized in the following statements.

Career Choice↗
PubMed1995

The physician executive "arrives"--a new generation prepares for the future.

The recent rise in the number of physician executives in the health care industry vividly demonstrates that a genuinely new generation of physician executives is seeking to combine the sensitivity of their clinical skills with the business acumen that today's health care organizations need to prosper and grow. But physicians who are preparing themselves to be selected one day as chief executive officers by hospitals, integrated systems, and managed care organizations should understand that the CEO role is radically different from that of the CEO of a physician practice. The corporate CEO role requires the management of managers and responsiveness to the organization's board. Those who imagine that the corporate CEO role bears any resemblance to the autonomous, independent existence of the practitioner are certain to have a rough time.

Career Mobility↗
PubMed1994

What kind of leaders will be successful?

The U.S. health care system is fundamentally changing. The pace of change is swift but will vary, depending on regional market forces and state legislative mandates. This complex change is leading to rapid market consolidation of providers and insurers into organizations called "integrated health care systems." There is, as yet, no proven role model that will guarantee success. The purpose of this article is two-fold: To help individuals who see an expanding role for themselves in integrated health care management decide if they have what it is going to take to be successful. To identify individual management training needs by use of a self-evaluation tool. Some of the needed skills can be enhanced by education and experience. However, some are personality and style characteristics that may not be changeable.

Comprehensive Health Care↗
PubMed1991

Panel sees high demand for diverse CFO skills.

A more sophisticated healthcare industry, challenged by competition and payer demands, also looks for sophistication when filling its senior financial positions. Individuals with experience in managed care contract negotiations, knowledge of hospital-physician ventures, and superior planning and treasury management skills are increasingly sought by hospitals. Some organizations also may single out chief financial officers able to assume broader administrative duties, including chief executive officer positions. These are among the observations of a panel convened by HFMA to discuss recent trends in healthcare executive recruiting. Highlights of the session, moderated by HFMA President Richard L. Clarke, FHFMA, follow.

Employment↗
PubMed1987

Pilot study using 'dangerous answers' as scoring technique on certifying examinations.

Four medical specialty certifying boards collaborated in an exploratory project to determine whether "dangerous answers," that is, incorrect answers that would be dangerous in patient care, could be identified in written board examinations and used as a potential technique for scoring. Panels of experts in each specialty retrospectively identified in previously administered certifying examinations those multiple-choice questions that contained dangerous incorrect options. The 2,713 certification candidates who took these examinations from 1981 through 1983 were given dangerous answer scores based on their responses to these items. When these dangerous answer scores were compared with their conventional percent-correct scores, it was found that 3 percent of the candidates who failed the examinations by conventional scoring had fewer than the average dangerous incorrect answers. More important, 10 percent of the candidates who passed the examinations by conventional scoring chose a greater than average number of dangerous answers. The implications of these preliminary findings and the limitations of the study are discussed.

Achievement↗