The true complexities of "standard" family practice visits unmasked: an observational cross-sectional study in Regina.

BACKGROUND: Many patients present to their family medicine clinic with more than one health concern, placing an increased demand on family physicians. Research into the average number of concerns per regular family medicine visit is limited. Recognition of the frequency that family physicians address more than one concern per visit and adapting practices accordingly is important for improving patient care. OBJECTIVE: To examine whether family physicians routinely address multiple different patient concerns during a single visit and if this is influenced by patient demographics. METHODS: This study was conducted at a multi-physician family medicine clinic in Regina, Saskatchewan, Canada. Five physicians contributed their 500 most recent charts, extending retrospectively from 1 June 2023, from in-person visits by patients over 18 years of age and billed as regular appointments without billed procedures. Each chart was reviewed for the number of concerns addressed in the visit. RESULTS: Fifty percent of visits addressed more than 1 concern (range = 1-8). A generalized linear mixed model using Poisson distribution showed certain physicians (incident rate ratio [IRR]: 1.192, 95% CI: 1.087-1.307, P < 0.001) and adults older than 65 years compared to adults less than 40 years (IRR 1.151, 95% CI: 1.069-1.239, P < 0.001) were more likely to present with multiple concerns, but patient sex was not a significant predictor. CONCLUSIONS: Family physicians routinely address more than one concern per visit. Standard visit length and billing practices should be adapted to reflect this complexity.

Interpretation and management of genetic test results by Canadian family physicians: a multiple choice survey of performance.

Family physicians (FPs) will encounter genetic concerns within community practice. To determine how FPs compare to genetic counselors (GCs), a cross-sectional survey was distributed to Canadian FPs and GCs in 2019. The survey assessed risk analysis, counseling, and management of genetic information. FPs performed less well than GCs on each survey question and scenario (p < 0.05). Average overall survey scores for FPs were lower than GCs (62% vs. 93%, p < 0.001). Additional genetic training for FPs may help avoid potential harm.

Interaction of the P-Glycoprotein Multidrug Transporter with Sterols.

The ABC transporter P-glycoprotein (Pgp, ABCB1) actively exports structurally diverse substrates from within the lipid bilayer, leading to multidrug resistance. Many aspects of Pgp function are altered by the phospholipid environment, but its interactions with sterols remain enigmatic. In this work, the functional interaction between purified Pgp and various sterols was investigated in detergent solution and proteoliposomes. Fluorescence studies showed that dehydroergosterol, cholestatrienol, and NBD-cholesterol interact intimately with Pgp, resulting in both quenching of protein Trp fluorescence and enhancement of sterol fluorescence. Kd values indicated binding affinities in the range of 3-9 µM. Collisional quenching experiments showed that Pgp-bound NBD-cholesterol was protected from the external milieu, resonance energy transfer was observed between Pgp Trp residues and the sterol, and the fluorescence emission of bound sterol was enhanced. These observations suggested an intimate interaction of bound sterols with the transporter at a protected nonpolar site. Cholesterol hemisuccinate altered the thermal unfolding of Pgp and greatly stabilized its basal ATPase activity in both a detergent solution and reconstituted proteoliposomes of certain phospholipids. Other sterols, including dehydroergosterol, did not stabilize the basal ATPase activity of detergent-solubilized Pgp, which suggests that this is not a generalized sterol effect. The phospholipid composition and cholesterol hemisuccinate content of Pgp proteoliposomes altered the basal ATPase and drug transport cycles differently. Sterols may interact with Pgp and modulate its structure and function by occupying part of the drug-binding pocket or by binding to putative consensus cholesterol-binding (CRAC/CARC) motifs located within the transmembrane domains.

Lipid bilayer properties control membrane partitioning, binding, and transport of p-glycoprotein substrates.

The ABC protein P-glycoprotein (Pgp or ABCB1) is a multidrug efflux pump capable of transporting many structurally diverse substrates from within the lipid bilayer. Previous studies have demonstrated the importance of the membrane in modulating Pgp function, but few have quantified these effects. We employed purified Pgp reconstituted into phospholipid bilayers with defined gel to liquid-crystalline melting transitions to investigate the effect of membrane environment on the transporter and three of its substrates. Equilibrium dialysis measurements indicated that Hoechst 33342, LDS-751, and MK-571 partitioned much more readily into liquid-crystalline phase bilayers than into gel phase bilayers. However, drug binding affinities revealed that Pgp bound the three substrates more tightly when the lipid bilayer was in the gel phase. The binding affinity of the transporter for substrates within the bilayer was low, in the millimolar range, suggesting that it interacts with them weakly. Thermodynamic analysis revealed that both drug-Pgp and drug-lipid interactions contribute to binding affinity. The kinetics of LDS-751 and Hoechst 33342 transport by reconstituted Pgp was monitored using a real-time fluorescence-based assay to obtain apparent turnover frequencies. Transport rates were found to be sensitive to both drug structure and lipid environment. Arrhenius and transition state analysis of transport rates suggested that the rate of drug transport depends on both the affinity of Pgp for substrate and protein conformational changes. Transport rates did not appear to be limited exclusively by the rate of ATP hydrolysis and may be partially controlled by the rate of drug dissociation.

The origin of the conductivity maximum in molten salts. I. Bismuth chloride.

A new theory is presented to explain the conductivity maxima of molten salts (versus temperature and pressure). In the new theory, conductivity is due to ions hopping from counterion to counterion, and its temperature dependence can be explained with an ordinary Arrhenius equation in which the frequency prefactor A (for hopping opportunities) and activation energy E(a) (for hopping) are density dependent. The conductivity maximum is due to competing effects: as density decreases, the frequency of opportunities for hopping increases, but the probability that an opportunity is successfully hopped decreases due to rising E(a) caused by the increased hopping distance. The theory is successfully applied to molten bismuth (III) chloride, and supported by density-functional based molecular dynamics simulations which not only reproduce the conductivity maximum, but disprove the long-standing conjecture that this liquid features an equilibrium between BiCl(3) molecules, and BiCl(2)(+) and BiCl(4)(-) ions that shifts to the left with increasing temperature.