Advanced glycation end-products (AGEs) and functionality of reverse cholesterol transport in patients with type 2 diabetes and in mouse models

AIMS/HYPOTHESIS

We investigated the contribution of AGEs to the impairment of reverse cholesterol transport (RCT) variables in diabetic individuals and in two animal models of diabetic obesity and of renal impairment.

METHODS

The capacity of plasma and HDL from 26 individuals with moderately controlled type 2 diabetes to support cholesterol efflux was compared with 26 age- and sex-matched individuals without diabetes. We also compared the rates of RCT in vivo in two animal models: db/db mice and mice with chronic renal failure.

RESULTS

Diabetic individuals had characteristic dyslipidaemia and higher levels of plasma AGEs. The capacity of whole plasma, ApoB-depleted plasma and isolated HDL to support cholesterol efflux was greater for diabetic patients compared with controls despite their lower HDL-cholesterol levels. The capacity of plasma to support cholesterol efflux correlated with plasma levels of cholesteryl ester transfer protein and levels of ApoB, but not with levels of AGE. RCT was severely impaired in db/db mice despite elevated HDL-cholesterol levels and no change in AGE concentration, whereas RCT in uraemic mice was unaffected despite elevated AGE levels.

CONCLUSIONS/INTERPRETATION

AGEs are unlikely to contribute significantly to the impairment of RCT in type 2 diabetes.

Reactive oxygen species generation at the plasma membrane for antibody control

Generation of reactive oxygen species (ROS) at the plasma membrane can be a vehicle for oxidative unmasking or masking of auto antibodies in a tissue selective and controlled way. There are seven related NADPH oxidases (NOX 1-5, DuoNOX 1,2) which can be activated in various ways to produce superoxide and hydrogen peroxide at the plasma membrane. There is also a plasma membrane NADH oxidase which is under different control. ROS can also be produced by mitochondria or cytosolic oxidases under special conditions. The ROS generation provides oxidant for thiol oxidation or peroxynitrite formation which can be a basis for antibody modification. The specific controls of the oxidases in different tissues allow a basis for localized autoantibody modification in response to stress or environment.

Hypothermic circulatory arrest in the treatment of thoracic aortic lesions

The use of hypothermic circulatory arrest has been established in the treatment of aortic arch lesions. We recently used this method of arrest in the treatment of 10 consecutive patients with thoracic aortic lesions. Seven of these patients had dissecting aneurysms of the ascending aorta with extension into the aortic arch. One patient had a mycotic aneurysm of the arch, and 2 patients had arteriosclerotic aneurysms of the ascending aorta and entire aortic arch. All patients were supported and cooled with cardiopulmonary bypass. Circulatory arrest was maintained for periods of 21 to 63 minutes. All 10 patients survived the operative procedure. Nine patients remained intact neurologically. Renal function returned to baseline in all patients. Average blood replacement was 2.9 units. All patients have experienced an excellent surgical result. The average follow-up is 21.1 months. The technique facilitates a surgical approach to these lesions and appears to be the safest form of vital-organ preservation.

Understanding and expectation towards pharmaceutical care among patients, caregivers and pharmacy service providers: a qualitative study

Background

Over the past decades, the pharmacist's role has changed from being 'compounders and dispensers' to one of 'medication therapy manager' providing pharmaceutical care (PC). The transformation of pharmacy practice and its benefits, however, seem to be poorly understood by patients and caregivers (consumers) even in advanced health systems.

Objective

This study aims to assess the comprehension of consumers in Singapore towards PC and expectations on the scope of pharmacy services today.

Methods

This qualitative study was conducted among 51 consumers and pharmacy staff (pharmacy providers) in a tertiary acute care hospital in Singapore through 45 semi-structured interviews. Participants were sampled from inpatient and outpatient settings. Data were transcribed, coded and analysed by thematic analysis.

Results

Thirteen pharmacy technicians, 14 pharmacists and 14 out of 24 patients and caregivers, agreed to be interviewed. Reasons such as minimal English and unsure of pharmacy services were cited for declining interviews. From the interviews, the majority of the consumers did not understand the differences in roles between pharmacists and doctors beyond the basics of doctors diagnosing and pharmacists dispensing. Eighteen (75%) consumers remain unaware that pharmacists are trained to provide additional services such as medication enquiry services and optimisation of drug therapy. In addition, consumer expectations have expanded beyond transactional encounters, with 15 (63%) consumers expecting personalised services. Five (19%) pharmacy providers also expect the use of automation to boost efficiency and improve patients' convenience. Seven (15%) of the participants hope to see better prediction with analytics and, therefore, pre-emptive management of medication errors.

Conclusions

There is an incomplete understanding regarding PC and the roles of pharmacy providers among healthcare consumers today. Beyond basic service provisions, expectations of pharmacy practice have become more experience-oriented. Policy changes that expand pharmacists' roles must be matched with corresponding publicity and education efforts to encourage service utilisation.

Fluorescence-detected magnetic circular dichroism of fluorescent and nonfluorescent molecules

We have modified a spectrometer for the measurement of fluorescence-detected magnetic (and natural) circular dichroism (FDMCD). The instrument can be operated either in a direct mode in which the average and polarization-induced differential fluorescent intensities are recorded separately or in a mode which records their ratio. We have measured the FDMCD of tryptophan, which is itself fluorescent. With the aid of an added fluorescent molecule we also measured the FDMCD of Fe(III) cytochrome c, which is nonfluorescent. In both cases, the FDMCD agreed with the conventional transmission-detected magnetic circular dichroism within experimental uncertainty. The FDMCD of both fluorescent and nonfluorescent molecules is potentially a useful technique for investigating optically dense materials and biological molecules in their native environments and systems in which there is inter- or intramolecular energy transfer.

P33 On lambs, DBS, and diathermy

Objectives

Over 1 50 000 patients have been treated with deep brain stimulation (DBS), but some aspects of their ongoing management are poorly defined. Guidelines for the use of electrocautery in patients undergoing further surgery are vague, suggesting the use of bipolar cautery only. However there is likely to be a safe limit for the use of monopolar electrocautery, a useful if not necessary adjunct for most surgeons. Establishing this would be valuable.

Design

Literature review, correspondence with equipment representatives, and animal cadaveric model.

Methods

PubMed, the Cochrane Database, and Google Scholar were used for the literature review. Technical team advisers were approached for DBS systems and electrocautery devices. A commercially available freshly slaughtered lamb was prepared in a room with constant ambient temperature. A DBS system was implanted in tandem with a thermocouple at depths and distances matching patient practice. Monopolar electrocautery was employed in coagulation and cutting modes at set distances and levels with constant temperature recording. The implant site was examined microscopically post procedure.

Results

The current ‘ban’ on monopolar use appears to be extrapolated from the use of medical diathermy, a very different modality. At no point did the implant site temperature rise more than 2.4°C. Microscopic analysis post procedure revealed no thermal damage.

Conclusions

Electrocautery in the context of DBS is safer than previously thought.

[Orthogonal test analysis of compressive strength of porous hydroxylapatite prepared by gel-casting process]

Porous hydroxylapatite (HA) has excellent osseous inductive ability. It has been prepared by gel-casting process, which is feasible and can make complex ceramic material. According to the result of orthogonal test based on the compressive strength, the order and the level of the factors, including monomer HA, initiator MBAM, catalyst APS and water, were dealt with. The effects of drying and sintering technique on the properties of porous hydroxylapatite were also researched. The results showed that the order of every factor in the gel-casting process is as follows, AM-APS, MBAM, H2O. Based on the determined level of each factor, the suitable slurry constituents and drying and sintering technologies were selected, and the porous hydroxylapatite with compressive strength of 6-7 MPa was produced.

[Capillary blood flow with dynamical change of tissue pressure caused by exterior force]

A hemodynamic model of capillary and tissue, in which tissue pressure changed with swing manipulation of Traditional Chinese Medical Massage (TCMM), is presented in this paper to explain the hemodynamic mechanism of swing manipulation. Blood flowed in capillary with low Reynolds number. Plasma exuded through capillary according to the Starling's Law. Tissue pressure changed linearly with the massage force measured. Blood apparent viscosity, plasma protein concentration and red cell's hematocrit were taken into account. Capillary flow rate, blood apparent viscosity, filtration rate and filtration fraction with dynamical change of tissue pressure were calculated numerically, and were compared with those in static tissue pressure condition. Results showed that, dynamical change of tissue pressure led to the increase of capillary flow rate and the decrease of blood apparent viscosity, which qualitatively explained the hemodynamic mechanism of "promoting blood circulation and removing blood stasis" in swing manipulation of TCMM.