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Biomedical subjects

A Lack

Publications and source records attributed to A Lack.

9 recordsLinked to original sources
PubMed2000

Weights for waits: lessons from Salisbury.

OBJECTIVES: This paper describes a waiting list patients' points scheme under development in Salisbury, UK, for the fair management of elective inpatient and day case waiting lists. The paper illustrates how points can be assigned to patients on a waiting list to indicate their relative unmet need, and illustrates the impact on case mix and resource use of the implementations of the points system versus 'first come, first served'. The paper explores a range of philosophical and technical questions raised by the points system. METHODS: The Salisbury Priority Scoring System enables surgeons to assign relative priority to patients at the time they are placed on a waiting list for elective health care. Points are assigned to patients to reflect the rate of progress of their disease, pain or distress, disability or dependence on others, loss of usual occupation and time already waited. In recognition of the need for resource planning alongside the prioritization of elective inpatients and day case waiting lists, a range of iso-resource groups has been developed for all procedures on these lists. These categorize procedures in terms of their resource use (i.e. bed days and theatre time required). RESULTS: In a modelling exercise, application of the Salisbury Points Scheme to a 'first come, first served' orthopaedic waiting list produced considerable changes in the order of patients to be treated. Only seven patients appeared in the first 20 patients to be treated under both regimes. The Salisbury Scheme required fewer resources to treat its first 20 patients than 'first come, first served' and met more Salisbury-defined 'need', but eliminated fewer days of waiting from the list. CONCLUSIONS: Development of a points scheme and iso-resource groupings opens up opportunities for more sophisticated purchasing, based on treating patients in order of unmet need rather than according to arbitrary maximum waiting time guarantees, as has been the dominant policy on waiting lists pursued in the UK, Australia, and Sweden, to date. However, such schemes raise three issues: first, the necessity of defining need as a composite of clinical and social factors; second the necessity to determine the acceptability of explicit prioritization to both health care professionals and patients; third, the thorny issue of whether such prioritization schemes will lead to 'gaming' by well-meaning general practitioners and specialists, aiming to secure the priority of their own patients and clinical specialty. Rigorous piloting of schemes, such as that developed at Salisbury, will be required to identify their dynamic effect over time on case mix, waiting time and resource use.

Delivery of Health Care↗
PubMed1998

Internet teleconferencing as a clinical tool for anesthesiologists.

Internet teleconferencing software can be used to hold "virtual" meetings, during which participants around the world can share ideas. A core group of anesthetic medical practitioners, largely consisting of the Society for Advanced Telecommunications in Anesthesia (SATA), has begun to hold regularly scheduled "virtual grand rounds." This paper examines currently available software and offers impressions of our own early experiences with this technology. Two teleconferencing systems have been used: White Pine Software CU-SeeMe and Microsoft NetMeeting. While both provided acceptable results, each had specific advantages and disadvantages. CU-SeeMe is easier to use when conferences include more than two participants. NetMeeting provides higher quality audio and video signals under crowded network conditions, and is better for conferences with only two participants. While some effort is necessary to get these teleconferencing systems to work well, we have been using desktop conferencing for six months to hold virtual Internet meetings. The sound and video images produced by Internet teleconferencing software are inferior to dedicated point-to-point teleconferencing systems. However, low cost, wide availability, and ease of use make this technology a potentially valuable tool for clinicians and researchers.

Anesthesiology↗
PubMed1994

Evidence that phenol phosphorylation to phenylphosphate is the first step in anaerobic phenol metabolism in a denitrifying Pseudomonas sp.

Anaerobic phenol degradation has been shown to proceed via carboxylation of phenol to 4-hydroxybenzoate. However, in vitro the carboxylating enzyme was inactive with phenol; only phenylphosphate (phosphoric acid monophenyl ester) was readily carboxylated. We demonstrate in a denitrifying Pseudomonas strain that phenylphosphate is the first detectable product formed from phenol in whole cells and that subsequent phenylphosphate consumption parallels 4-hydroxybenzoate formation. These kinetics are consistent with phosphorylation being the first step in anaerobic phenol degradation. Various cosubstrates failed so far to act as phosphoryl donor for net phosphorylation of phenol in cell extracts. Yet, cells anaerobically grown with phenol contained an enzyme that catalyzed an isotope exchange between [U-14C]phenol and phenylphosphate. This transphosphorylation activity was anaerobically induced by phenol but was stable under aerobic conditions and required Mn2+ and polyethylene glycol. Activity was optimal at pH 5.5 and half-maximal with 0.6 mM Mn2+, 0.2 mM phenylphosphate, and 1 mM phenol. It is proposed that the phenol exchange/transphosphorylation reaction is catalyzed as partial reaction by an inducible phenol phosphorylating enzyme. The isotope exchange demands that a phosphorylated enzyme was formed in the course of the reaction, which might be similar to the phosphotransferase system of sugar transport.

Anaerobiosis↗
PubMed1992

Carboxylation of phenylphosphate by phenol carboxylase, an enzyme system of anaerobic phenol metabolism.

Several lines of evidence indicate that the first step in the anaerobic metabolism of phenol is phenol carboxylation to 4-hydroxybenzoate; this reaction is considered a biological Kolbe-Schmitt carboxylation. A phenol carboxylase system was characterized by using a denitrifying Pseudomonas strain, K 172, which catalyzes an isotope exchange between 14CO2 and the carboxyl group of 4-hydroxybenzoate. The enzymatic isotope exchange activity (100 nmol min-1 mg-1 of protein) requires Mn2+ and K+. We show that this system also catalyzes the carboxylation of phenylphosphate (the phosphoric acid monophenyl ester) to 4-hydroxybenzoate and phosphate. The specific activity of phenylphosphate carboxylation at the optimal pH of 6.5 is 12 nmol of CO2 fixed min-1 mg-1 of protein. Phenylphosphate cannot be replaced by Mg(2+)-ATP and phenol. The carboxylase activity requires Mn2+ but, in contrast to the isotope exchange activity, does not require K+. The apparent Km values are 1.5 mM dissolved CO2 and 0.2 mM phenylphosphate. Several convenient assays for phenylophosphate carboxylation are described. The isotope exchange reaction and the net carboxylation reaction are catalyzed by the same oxygen-sensitive enzyme, which has a half-life in an air-saturated solution of less than 1 min. Both activities cochromatographed with a protein with a Mr of 280,000, and both activities were induced only after anaerobic growth on phenol. The carboxylation of phenylphosphate suggests that phenylphosphate itself is the physiological CO2 acceptor molecular of this novel CO2 fixation reaction. Alternatively, phenylphosphate could simulate the unknown natural precursor. It is suggested that the formation of an enzyme-bound phenolate anion from the activated phenolic compound is the rate-determining step in the carboxylation reaction.

Adenosine Triphosphate↗
PubMed1991

Catalytic properties of phenol carboxylase. In vitro study of CO2: 4-hydroxybenzoate isotope exchange reaction.

Phenol is metabolized in a denitrifying bacterium in the absence of molecular oxygen via para-carboxylation to 4-hydroxybenzoate (biological Kolbe-Schmitt synthesis). The enzyme system catalyzing the presumptive carboxylation of phenol, tentatively named 'phenol carboxylase', catalyzes an isotope exchange between 14CO2 and the carboxyl group of 4-hydroxybenzoate (specific activity 0.1 mumol 14CO2 incorporated into 4-hydroxybenzoate x min-1 x mg-1 cell protein) which is considered a partial reaction of the overall enzyme catalysis; 14C from [14C]phenol was not exchanged into 4-hydroxybenzoate ring positions to a significant extent. The 14CO2 isotope exchange reaction was studied in vitro. The reaction was dependent on the substrates CO2 and 4-hydroxybenzoate and required K+ and Mn2+. The actual substrate was CO2 rather than HCO3-. The apparent Km values were 1 mM dissolved CO2, 0.2 mM 4-hydroxybenzoate, 2 mM K+, and 0.1 mM Mn2+. The cationic cocatalysts could be substituted by ions of similar ionic radius: K+ could be replaced to some extent by Rb+, but not by Li+, Na+, Cs+, or NH4+; Mn2+ could be replaced to some extent by Fe2+ greater than Mg2+, Co2+, but not by Ni2+, Zn2+, Ca2+, or Cu2+. The exchange reaction was not strictly specific for 4-hydroxybenzoate, however it required a p-hydroxyl group; derivatives of 4-hydroxybenzoate with OH, CH3 or Cl substituents in m-position did react, whereas those with substitutions in the o-position were inactive or were inhibitory. The enzyme was induced when cells were grown on phenol, but not on 4-hydroxybenzoate. Comparison of SDS/PAGE protein patterns of cells grown on phenol or 4-hydroxybenzoate revealed several additional protein bands in phenol-grown cells. The possible role of similar enzymes in the anaerobic metabolism of phenolic compounds is discussed.

Carbon Dioxide↗