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Biomedical subjects

D L Baines

Publications and source records attributed to D L Baines.

32 records · Page 2Linked to original sources
PubMed1998

Culture substrate-specific expression of P2Y2 receptors in distal lung epithelial cells isolated from foetal rats.

ATP and UTP did not evoke [Ca2+]i signals in rat foetal lung epithelial cells grown on glass but elicited clear responses in cells grown into functionally polarised epithelia on permeable supports. Moreover, P2Y2 receptor mRNA could not be detected in cells on glass by the polymerase chain reaction but this mRNA species was clearly expressed by polarised cells. P2Y2 receptor expression thus appears to be a feature of the polarised phenotype.

Adenosine Triphosphate↗
PubMed1998

Assessing efficiency in general practice: an application of data envelopment analysis.

As with any health care process, the efficiency with which outputs are produced in general practice is of considerable importance. Using data from Lincolnshire, this study utilizes data envelopment analysis to examine the relationships between practice costs and outputs, measured not only as the number of patients treated, but also on the basis of performance indicators. The technique permits the construction of an efficiency ranking, facilitating the accurate targeting of monitoring resources.

Benchmarking↗
PubMed1998

Salt and water transport across the alveolar epithelium in the developing lung: correlations between function and recent molecular biology advances (Review).

Significant progress have been made in understanding the mechanisms of alveolar fluid clearance at the time of birth and the transition from placental oxygenation to air breathing. During fetal life, the mammalian lung is a fluid filled secretory organ that fills no respiratory function. Its potential air spaces are filled with fluid that is actively secreted in response to an osmotic force generated by Cl(-)-secretion and the fluid-filled lung is necessary for a proper development of the air-breathing lung. As term approaches, net Cl(-)-secretion decreases, which is accompanied by a decreased secretion rate of the fluid into the air spaces. Concomitantly with the decreased Cl(-)-secretion, the alveolar epithelium begins to absorb Na+ to prepare for fluid absorption and the air breathing life. The causes for the decreased Cl(-)-secretion and the beginning of the Na+ absorption are not clear. Alterations in the hormonal milieu of the lung as well as changes in plasma stress hormone levels have been suggested to play roles. The switch from a placental oxygenation to pulmonary oxygenation requires that the fluid in the air spaces be rapidly removed from the lung lumen. Recent studies have demonstrated that removal of the alveolar fluid at birth is regulated via endogenous plasma epinephrine in the newborn. Molecular, cellular, and whole animal in vivo studies have demonstrated that fluid absorption at birth is related to expression and function of the epithelial sodium channel (ENaC). Several different in vivo and in vitro preparations have been used to investigate the mechanisms of alveolar fluid transport, primarily in adult lungs and have demonstrated that alveolar fluid absorption is driven by active Na+ transport. Both catecholamine-dependent and -independent regulatory mechanisms have been identified, probably acting on ENaC and other apical sodium channels and/or the basolaterally located Na+, K(+)-ATPase. Future studies are needed to integrate new insights to the molecular mechanisms behind fluid clearance with their function in both normal and pathological lungs.

Animals↗
PubMed1997

Inwardly rectifying K+ currents of alveolar type II cells isolated from fetal guinea-pig lung: regulation by G protein- and Mg2+-dependent pathways.

K+ currents in alveolar type II cells, isolated from fetal guinea-pig lung, were studied using the whole-cell patch-clamp technique. Inwardly rectifying (IR) K+ currents were observed when cells were bathed in symmetrical KCl-rich solutions. When extracellular K+ was replaced by Na+, inward currents were greatly decreased and the zero-current potential moved from 0 mV to -69 mV, indicating high K+ selectivity. In recordings with an intracellular KCl-rich solution, containing 1.12 mM Mg2+ and 10(-8 )M free Ca2+, IR K+ currents slowly diminished with time. Addition of the irreversible G protein activator, guanosine 5'-O-(3-thiotriphosphate) (GTP [gamma-S]), to the intracellular solution accelerated the rate of current run-down. In experiments where the intracellular solution was Mg2+ free, current run-down was abolished. The rate of current run-down was found to increase with increasing free intracellular [Mg2+]. Raising the intracellular free [Ca2+] to 10(-6 )M under Mg2+-free conditions had no effect on the K+ currents. Extracellular Ba2+ blocked the IR K+ currents in a concentration- and voltage-dependent manner. Tolbutamide, a blocker of ATP-sensitive K+ (KATP) channels, had no effect on the currents. The single channel underlying the whole-cell IR K+ currents displayed inward rectification and had a conductance of 31 pS in symmetrical KCl-rich solutions. We demonstate that mRNA coding for IRK1 is expressed in this cell preparation. Possible functions for this channel are discussed.

Animals↗
PubMed1997

GP fundholding and the costs of prescribing: further results.

BACKGROUND: An earlier paper published in this journal suggested that fundholding practices in Lincolnshire had managed to constrain the growth in their prescribing costs more successfully than had non-fundholders, largely on the basis of restricting the number of items prescribed per patient. At that time, insufficient data were available to explore the impact of a change in status from non-fundholding to fundholding on prescribing behaviour. METHOD: Time-series prescribing data for the fourth-wave of Lincolnshire fundholders are analysed, and comparisons are made between this group, non-fundholders and the fundholders of the earlier waves. RESULTS: In their first year of fundholding, fourth-wave practices adopted the prescribing strategies employed previously by existing fundholders, namely, reductions in the number of items prescribed per patient and substantial increases in generic prescribing. The hypothesis that prospective fundholders inflate their prescribing budget before attaining fundholding status is not generally supported by the Lincolnshire data. Evidence is presented which suggests that the prescribing cost economies accruing to fundholding status may be short term. CONCLUSIONS: With the acquisition of fundholding status, the structure of incentives facing practices changes. Our results suggest that, with respect to prescribing, practices adjust rapidly to the new incentive structure.

Drug Costs↗
PubMed1997

General practitioner fundholding and prescribing expenditure control. Evidence from a rural English health authority.

In April 1991, the fundholding and indicative prescribing schemes introduced budgets for expenditure on prescribed drugs into UK general practice. Although both schemes were designed to be equally effective at containing prescribing-cost inflation, several studies suggest that expenditure growth has been lower in fundholding practices, compared with nonfundholding practices. This study attempts to ascertain how fundholding practices control their expenditure by examining data from a rural English health authority for the financial year 1993 to 1994. The fundholding practices sampled were found to control their expenditure through: (i) reduced overprescribing; (ii) using fewer drugs that have limited clinical value; (iii) substituting similar, but less expensive, drugs; (iv) more generic prescribing; and (v) appropriate use of expensive preparations. However, whether the cost differential between fundholding and nonfundholding practices is sustained in future years will depend upon: (i) the ability of fundholding practices to generate further savings; (ii) the characteristics of the practices that enter the fundholding scheme in subsequent waves; (iii) the way in which the scheme is organised; and (iv) the level at which budgets are set.

Cost Control↗
PubMed1997

Over-the-counter drugs and prescribing in general practice.

BACKGROUND: Both the government and the pharmaceutical industry are interested in increasing the use of over-the-counter (OTC) medicines. The reaction on the part of general practitioners is more circumspect. AIM: To investigate whether fundholding or dispensing status and patient exemption from, or prepayment of prescription charges influence the behaviour of general practitioners with respect to prescribing preparations otherwise available OTC. METHOD: Regression analysis of data for all 105 Lincolnshire practices for the fiscal year 1993-94, using the number of items prescribed by the practice that were also available OTC as the outcome variable. Comparison of Audit Commission Thematic Analysis of Prescribing (ACTAP) data for fundholders' and non-fundholders' OTC prescribing in the same year. RESULTS: The prescription of medicines otherwise available OTC is less likely when the practice is fundholding and more likely when the practice has dispensing status. Prescription of such medicines also increases as the proportion of patients exempt from, or having prepaid prescription charges increases.

Attitude of Health Personnel↗
PubMed1997

GP fundholding and prescribing in UK general practice: evidence from two rural, English Family Health Services Authorities.

BACKGROUND: Two separate prescribing budget regimes (part of GP fundholding and the indicative prescribing scheme) were introduced into UK general practice in April 1991 in an attempt to contain the growth in NHS expenditure on prescribed drugs. OBJECTIVES: The aims of this study are (i) to examine whether the fundholding scheme has been more effective at containing prescribing cost growth than the indicative prescribing scheme and (ii) to ascertain whether its implementation, at a practice level, has been affected by local circumstances and conditions. METHODS: Prescribing cost data were collected from two rural, English Family Health Services Authorities for the financial years 1990/1991 to 1993/1994. Exploratory analysis was performed using regression analysis and nonparametric statistical techniques. RESULTS AND CONCLUSIONS: Initially, the fundholding scheme has been the more effective at containing expenditure on prescribed drugs. However, the implementation of the schemes in rural areas has probably been affected by the existence of practices with permission to dispense drugs to their own patients, due to a lack of pharmacies in such areas.

Aged↗
PubMed1996

Explaining variations in the frequency of night visits in general practice.

BACKGROUND AND OBJECTIVE: The study identifies factors which explain variations in the frequency of night visits made by general practitioners, and is based on a cross-section regression analysis of practices in Lincolnshire in 1993. METHOD: The independent variables comprise 22 general practice characteristics, related to health and socio-demographic structure of practice lists, practice management and organization, location and social deprivation. RESULTS AND CONCLUSIONS: A final model containing 6 of the 22 variables originally entered succeeds in explaining 72 per cent of the variation in the frequency of night visits per GP per quarter-year. These variables are average list size per GP, frequency of home visits, maternity claims, list inflation owing to the influx of temporary residents, the number of proximate practices and unemployment.

Adult↗
PubMed1996

The costs of prescribing in dispensing practices.

The existence of significant disparities between the prescribing costs of dispensing and non-dispensing general practices has long been suspected, and received confirmation in a study of Lincolnshire, based on data for 1990-91. This study subsequently attracted much criticism. In this paper, we extend the analysis by considering annual cost and other prescribing data for Lincolnshire for the years between and including 1990-91 and 1993-94, in the light of the prescribing criteria developed by the Audit Commission. Our results show that dispensing practices had higher prescribing costs per patient for all the years analysed. In 1993-94, dispensing practices prescribed more items per patient (fewer of them generically) and were less capable of remaining within their prescribing budgets. The essential difference in prescribing costs lies in the area defined by the Audit Commission as 'core prescribing'. Using the Audit Commission's criteria for 'rational' prescribing, dispensing practices could make a significantly higher level of savings than non-dispensing practices. The findings lend support to the hypothesis advanced in the earlier analysis, namely, that the higher costs of prescribing in dispensing practices are accounted for primarily by management practice and the structure of incentives.

Drug Costs↗
PubMed1996

Activation of apical P2U purine receptors permits inhibition of adrenaline-evoked cyclic AMP accumulation in cultured equine sweat gland epithelial cells.

Experiments were undertaken using cultured equine sweat gland epithelial cells that express purine receptors belonging to the P2U subclass which allow the selective agonist uridine triphosphate (UTP) to increase the concentration of intracellular free Ca2+ ([Ca2+]i). Experiments using pertussis toxin (Ptx), which inactivates certain guanine-nucleotide-binding proteins (G-proteins), showed that this response consisted of Ptx-sensitive and Ptx-resistant components, and immunochemical analyses of the G-protein alpha subunits present in the cells showed that both Ptx-sensitive (alpha i1-3) and Ptx-resistant (alpha q/11) G-proteins were expressed. P2U receptors may, therefore, normally activate both of these G-protein families. Ptx-sensitive, alpha i2/3 subunits permit inhibitory control of adenylate cyclase, and UTP was shown to cause Ptx-sensitive inhibition of adrenaline-evoked cyclic AMP accumulation, suggesting that the receptors activate Gi2/3. Experiments using cells grown on permeable supports suggested that P2U receptors became essentially confined to the apical membrane in post-confluent cultures. Polarised epithelia may, therefore, express apical P2U receptors which influence two centrally important signal transduction pathways. It is highly improbable that these receptors could be activated by nucleotides released from purinergic nerves, but they may be involved in the autocrine regulation of epithelial function.

Adenylate Cyclase Toxin↗
PubMedDate not supplied

Selection bias in GP fundholding.

This paper uses a logistic regression model based on 1993 data for general practices in a single Family Health Services Authority (Lincolnshire) to analyse the differences in characteristics between existing fundholding (up to and including wave three) and non-fundholding practices. A high degree of classification accuracy is obtained. Fundholders are revealed to be more likely than non-fundholders to meet a number of the various quality criteria laid down by central government following the 1990 National Health Services Act, for example, with respect to prescribing cost control, minor surgery and cervical screening uptake. The model is employed to forecast the fourth wave of fundholding and poor predictions suggest the existence of a structural break in the characteristics of fundholders between those in the first three waves and those of wave four. The evidence presented also supports the existence of selection bias in the first three waves of fundholding, although further logistic regression analysis reveals a form of such bias in the fourth wave also.

Cost-Benefit Analysis↗