Association of age and packed red blood cell transfusion to 1-year survival--an observational study of ICU patients

OBJECTIVES

To compare the 1-year survival for different age strata of intensive care unit (ICU) patients after receipt of packed red blood cell (PRBC) transfusions.

BACKGROUND

Despite guidelines documenting risks of PRBC transfusion and data showing that increasing age is associated with ICU mortality, little data exist on whether age alters the transfusion-related risk of decreased survival.

METHODS

We retrospectively examined data on 2393 consecutive male ICU patients admitted to a tertiary-care hospital from 2003 to 2009 in age strata: 21-50, 51-60, 61-70, 71-80 and >80 years. We calculated Cox regression models to determine the modifying effect of age on the impact of PRBC transfusion on 1-year survival by using interaction terms between receipt of transfusion and age strata, controlling for type of admission and Charlson co-morbidity indices. We also examined the distribution of admission haematocrit and whether transfusion rates differed by age strata.

RESULTS

All age strata experienced statistically similar risks of decreased 1-year survival after receipt of PRBC transfusions. However, patients age >80 were more likely than younger cohorts to have haematocrits of 25-30% at admission and were transfused at approximately twice the rate of each of the younger age strata.

DISCUSSION

We found no significant interaction between receipt of red cell transfusion and age, as variables, and survival at 1 year as an outcome.

Skin autofluorescence is associated with past glycaemic control and complications in type 1 diabetes mellitus

As skin autofluorescence (AF) can assess subcutaneous accumulation of fluorescent advanced glycation end-products (AGEs), this study aimed to investigate whether it was linked to glycaemic control and complications in patients with type 1 diabetes mellitus (T1DM). Using the AGE Reader™, AF was measured in T1DM patients referred to Haut-Levêque Hospital (Bordeaux, France); data on their HbA1c levels measured every 6months as far back as the last 5years were also collected. The association of AF with the patients' past glucose control, based on their latest HbA1c values, and the means of the last five and 10 HbA1c values, and with diabetic complications was also examined by linear regression analysis. The sample included 300 patients: 58% were male; the mean age was 49 (SD 17) years and the mean diabetes duration was 21 (SD 13) years. The median skin AF measurement was 2.0 [25th-75th percentiles: 1.7-2.4] arbitrary units (AU), and this was associated with age (β=0.15 per 10years, P<0.001) and diabetes duration (β=0.17 per 10years, P<0.001). After adjusting for age and estimated glomerular filtration rate (eGFR), the skin AF measurement was also related to the means of the last five and 10 HbA1c values (β=0.10 per 1% of HbA1c, P=0.005, and β=0.13 per 1% of HbA1c, P=0.001, respectively). In addition, the skin AF was associated with retinopathy (P<0.001), albuminuria (P<0.001) and decreased eGFR (P<0.001). In conclusion, the skin AF is related to the long-term glucose control and diabetic complications.

The link between family history and risk of type 2 diabetes is not explained by anthropometric, lifestyle or genetic risk factors: the EPIC-InterAct study

AIMS/HYPOTHESIS

Although a family history of type 2 diabetes is a strong risk factor for the disease, the factors mediating this excess risk are poorly understood. In the InterAct case-cohort study, we investigated the association between a family history of diabetes among different family members and the incidence of type 2 diabetes, as well as the extent to which genetic, anthropometric and lifestyle risk factors mediated this association.

METHODS

A total of 13,869 individuals (including 6,168 incident cases of type 2 diabetes) had family history data available, and 6,887 individuals had complete data on all mediators. Country-specific Prentice-weighted Cox models were fitted within country, and HRs were combined using random effects meta-analysis. Lifestyle and anthropometric measurements were performed at baseline, and a genetic risk score comprising 35 polymorphisms associated with type 2 diabetes was created.

RESULTS

A family history of type 2 diabetes was associated with a higher incidence of the condition (HR 2.72, 95% CI 2.48, 2.99). Adjustment for established risk factors including BMI and waist circumference only modestly attenuated this association (HR 2.44, 95% CI 2.03, 2.95); the genetic score alone explained only 2% of the family history-associated risk of type 2 diabetes. The greatest risk of type 2 diabetes was observed in those with a biparental history of type 2 diabetes (HR 5.14, 95% CI 3.74, 7.07) and those whose parents had been diagnosed with diabetes at a younger age (<50 years; HR 4.69, 95% CI 3.35, 6.58), an effect largely confined to a maternal family history.

CONCLUSIONS/INTERPRETATION

Prominent lifestyle, anthropometric and genetic risk factors explained only a marginal proportion of the excess risk associated with family history, highlighting the fact that family history remains a strong, independent and easily assessed risk factor for type 2 diabetes. Discovering factors that will explain the association of family history with type 2 diabetes risk will provide important insight into the aetiology of type 2 diabetes.

84 EFFECT OF A STRESSOR ON CANINE SPERM DNA FRAGMENTATION USING THE SPERM CHROMATIN DISPERSION TEST

Recently, a new procedure for the analysis of sperm DNA fragmentation has been developed for human and different mammalian species (Sperm-Halomax®), based on the sperm chromatin dispersion test (SCDt); however, no studies has been performed specifically on canine frozen–thawed-stressed semen but is there for cooled semen. The aim of this work was to assess the effect of a stressor (24 h in an oven at 38°C) on canine frozen–thawed semen using the SCDt to resemble what happens in the female reproductive tract. For this purpose, ejaculates were collected by digital manipulation from 4 healthy beagle dogs and the sperm-rich fraction of the ejaculates from 3 different dogs was pooled each time. All the pooled semen samples (n = 4) used presented physiological values concerning to routine semen parameters (motility, morphology, and sperm concentration). After evaluation, semen samples were centrifuged and the sperm pellet resuspended to a final concentration of 100 × 106 sperm mL–1 in 2 steps with CaniPRO Freeze (Minitub, Tiefenbach, Germany). Sperm were slowly cooled to 5°C and then loaded into 0.5-mL plastic straws. After that, straws were frozen in liquid-nitrogen vapours for 10 min and stored into a nitrogen tank. Straws were thawed in a water bath (30 s/37°C) and incubated for 24 hours at 38°C before analysis. The sperm DNA fragmentation was assessed in fresh semen and frozen–thawed-stressed samples using the Sperm-Halomax® commercial kit specifically developed for canine semen (Halotech DNA SL, Madrid, Spain) following the manufacturer’s instructions. Slides were stained for green fluorescence staining and 500 sperm per slide were counted using fluorescence microscopy. The sperm DNA fragmentation index (%) was compared between fresh and frozen–thawed-stressed semen samples by ANOVA. Results were expressed as mean ± standard error of the mean. The results obtained showed that subjecting thawed semen to 24 h in an oven at 38°C significantly increased (P < 0.05) DNA fragmentation compared with fresh semen (2.7% ± 0.2 v. 1.4 ± 0.1%). The stress factor was performed to simulate the viability of canine thawed sperm (12–24 h) when a bitch is inseminated with frozen semen. It would be interesting to perform further studies to relate sperm DNA fragmentation and fertility of frozen–thawed canine semen. In conclusion, frozen–thawed-stressed semen samples increased the sperm DNA fragmentation index measured using a SCDt. Further studies are needed to relate sperm DNA fragmentation with fertility rates or cryopreservation success.

72 EFFECT OF SINGLE-LAYER CENTRIFUGATION WITH EQUIPURE™ ON MOTILITY KINEMATICS OF FROZEN - THAWED DONKEY SPERM

Single-layer centrifugation (SLC) with EquipureTM Bottom Layer has been used to enhance the quality of stallion semen samples; however, no studies have been performed on donkeys. The aim of this study was to determine if SLC with EquipureTM Bottom Layer improves kinematic parameters on frozen–thawed donkey sperm. Semen was collected from 4 Andalusian donkeys by artificial vagina. Three ejaculates from each donkey were centrifuged with EquiproTM, supernatant was removed, and pellet was re-extended in the freezing medium GentTM to a final concentration of 200 × 106 spermatozoa per milliliter. Sperm were slowly cooled to 5°C for 2 h, loaded in 0.5-mL plastic straws, and frozen in liquid-nitrogen vapors. After at least one week of storage, straws were thawed in a water bath at 37°C for 30 s. After thawing, semen samples were divided in 2 aliquots: aliquot 1 was used as such (control) and aliquot 2 was processed by SLC using EquipureTM Bottom Layer. Computer-assisted sperm analysis was performed, and sperm kinematics total motility (%), progressive motility (%), curvilinear velocity (VCL; µm s–1), velocity straight line (VSL; µm s–1), velocity average path (VAP; µm s–1), linearity (LIN; %), straightness (STR; %), wobble (WOB; %), lateral head displacement (ALH; µm), and beat cross frequency (BCF; Hz) were statistically compared using GLM model between frozen–thawed semen samples processed or not with EquipureTM. Results were expressed as mean ± standard error. Significant differences (P < 0.05) were found between SLC-selected and unselected semen for total motility (77.44 ± 5.83 v. 58.89 ± 6.07), progressive motility (76.88 ± 4.52 v. 56.59 ± 5.44), VCL (137.50 ± 0.75 v. 133.0 ± 0.99), LIN (69.43 ± 0.31 v. 68.23 ± 0.41), STR (78.45 ± 0.29 v. 76.90 ± 0.37), WOB (85.06 ± 0.18 v. 83.91 ± 0.26), ALH (2.76 ± 0.01 v. 2.44 ± 0.01), and BCF (9.13 ± 0.05 v. 8.53 ± 0.06), respectively. No significant differences were observed for VSL (102.89 ± 0.70 v. 104.32 ± 0.95) and VAP (123.21 ± 0.71 v. 121.50 ± 0.98). Most of the computer-assisted sperm analysis parameters used in the present study have been previously identified as reliable markers of sperm motility in relation to sperm quality and fertility. It has also been reported that VCL appears to be critical for the formation of the sperm reservoir and penetration of the zona pellucida. In addition, other variables improved in the SLC-selected samples have been described as measure of progressivity (LIN, STR) and spermatozoa vigor (BCF, ALH). These preliminary results suggest an additional option for improving sperm quality in donkey semen doses. In conclusion, SLC with EquipureTM can be used to enhance kinematic parameters on frozen–thawed donkey sperm.

14 FREEZING OF DONKEY SEMEN AFTER 24 HOURS OF COOL STORAGE: PRELIMINARY RESULTS

Several studies on sperm cooling and cryopreservation have been done in horses; however, only a few them have been developed in donkeys. In addition, no studies have been performed to freeze cooled stored donkey semen. Therefore, the aim of this study was to determine if it is possible to freeze donkey sperm after 24 h of cool storage. Semen was collected from 4 Andalusian donkeys by artificial vagina. After collection, each sample was separated into 2 aliquots; one of them was immediately frozen (t0) and the other one was cooled and stored before freezing (t24). The cryopreservation procedure consisted of a previous dilution of semen with EquiPro™. After that, semen was centrifuged and the sperm pellet resuspended with Gent® extender plus ethylene glycol (4%) to achieve a final concentration of 100 × 106 sperm mL–1. Sperm was slowly cooled to 5°C, loaded in 0.5-mL plastic straws and frozen in LN vapours. The second aliquot (t24) was diluted with Gent® extender to a final concentration of 50 × 106 sperm mL–1 and then cooled and stored at 5°C for 24 h. After that, cooled semen samples were cryopreserved following the same procedure as described above. Straws were thawed in a water bath at 37° for 30 s. Computer-assisted sperm motility analysis was performed. Total motility (TM), progressive motility (PM), and the following kinematic parameters: velocity curvilinear (VCL; µm s–1), velocity straight line (VSL; µm s–1), velocity average path (VAP; µm s–1), linearity (LIN; %), straightness (STR; %), wobble (WOB; %), amplitude of lateral head displacement (ALH; µm), and beat cross frequency (BCF; Hz) were compared between treatments by ANOVA. Results were expressed as mean ± standard error. Significant differences (P < 0.05) were found between treatments (t0 v. t24) for TM (63.76 ± 4.75 v. 51.67 ± 3.69), PM (36.01 ± 3.19 v. 27.24 ± 2.72), VCL (77.29 ± 0.65 v. 67.56 ± 0.78), VSL (58.50 ± 0.61 v. 52.11 ± 0.76), VAP (67.82 ± 0.64 v. 59.41 ± 0.79), LIN (57.90 ± 0.33 v. 59.53 ± 0.32), STR (70.39 ± 0.30 v. 72.43 ± 0.41), WOB (75.64 ± 0.22 v. 75.48 ± 0.32), ALH (1.88 ± 0.09 v. 1.69 ± 0.10), and BCF (6.28 ± 0.04 v. 6.51 ± 0.06). These preliminary results showed significant differences between cryopreservation at 0 and 24 h post-cooling; however, understanding that direct freezing is better in terms of sperm motility, cryopreservation of cooled stored semen could still be considered good according to the values obtained for sperm motility parameters after thawing. In our opinion, sperm centrifugation before cooling probably improve the results of cryopreservation 24 h post-cooling, due to the negative effect of seminal plasma on sperm viability during storage. In addition, the analysis of other sperm parameters would be useful to check more accurately differences between treatments. In conclusion, sperm motility parameters were higher in donkey semen samples immediately frozen after collection in comparison to semen samples cryopreserved after 24 h of cooling storage. Further studies are needed to improve cooling and cryopreservation procedures for freezing cooled stored donkey semen.

Low physical activity in patients with type 2 diabetes: the role of obesity

AIMS

Few studies have described ambulatory activity in free-living individuals with type 2 diabetes mellitus (T2DM) using motion sensors, and none included a control group. For this reason, our study compared the physical-activity levels of outpatients with T2DM with subjects without diabetes, and examined the relationship between body mass index (BMI) and physical-activity parameters.

METHODS

Physical-activity levels in 70 outpatients with T2DM and 30 age-, gender- and employment-matched individuals without diabetes were measured using the SenseWear Armband™, a monitoring device validated against doubly labelled water, to assess total energy expenditure. Patients wore the SenseWear Armband™ on their right arm continuously every day for 1 week.

RESULTS

Total energy expenditure (<300 kcal/day), number of steps (<1500/day), physical-activity duration (<130 min/day) and active energy expenditure/day (<300 kcal) were all significantly lower (P<0.05) in patients with T2DM. These measures were inversely correlated with BMI, and remained significant after adjusting for age, gender, employment status and the presence of diabetes.

CONCLUSION

Outpatients with T2DM have lower physical-activity levels than their matched controls, a characteristic that is related to their higher BMI.

Fruit and vegetable intake and type 2 diabetes: EPIC-InterAct prospective study and meta-analysis

Fruit and vegetable intake (FVI) may reduce the risk of type 2 diabetes (T2D), but the epidemiological evidence is inconclusive. The aim of this study is to examine the prospective association of FVI with T2D and conduct an updated meta-analysis. In the European Prospective Investigation into Cancer-InterAct (EPIC-InterAct) prospective case-cohort study nested within eight European countries, a representative sample of 16,154 participants and 12,403 incident cases of T2D were identified from 340,234 individuals with 3.99 million person-years of follow-up. For the meta-analysis we identified prospective studies on FVI and T2D risk by systematic searches of MEDLINE and EMBASE until April 2011. In EPIC-InterAct, estimated FVI by dietary questionnaires varied more than twofold between countries. In adjusted analyses the hazard ratio (95% confidence interval) comparing the highest with lowest quartile of reported intake was 0.90 (0.80-1.01) for FVI; 0.89 (0.76-1.04) for fruit and 0.94 (0.84-1.05) for vegetables. Among FV subtypes, only root vegetables were inversely associated with diabetes 0.87 (0.77-0.99). In meta-analysis using pooled data from five studies including EPIC-InterAct, comparing the highest with lowest category for FVI was associated with a lower relative risk of diabetes (0.93 (0.87-1.00)). Fruit or vegetables separately were not associated with diabetes. Among FV subtypes, only green leafy vegetable (GLV) intake (relative risk: 0.84 (0.74-0.94)) was inversely associated with diabetes. Subtypes of vegetables, such as root vegetables or GLVs may be beneficial for the prevention of diabetes, while total FVI may exert a weaker overall effect.

Hypoxic intensity: a determinant for the contribution of ATP and adenosine to the genesis of carotid body chemosensory activity

Excitatory effects of adenosine and ATP on carotid body (CB) chemoreception have been previously described. Our hypothesis is that both ATP and adenosine are the key neurotransmitters responsible for the hypoxic chemotransmission in the CB sensory synapse, their relative contribution depending on the intensity of hypoxic challenge. To test this hypothesis we measured carotid sinus nerve (CSN) activity in response to moderate and intense hypoxic stimuli (7 and 0% O(2)) in the absence and in the presence of adenosine and ATP receptor antagonists. Additionally, we quantified the release of adenosine and ATP in normoxia (21% O(2)) and in response to hypoxias of different intensities (10, 5, and 2% O(2)) to study the release pathways. We found that ZM241385, an A(2) antagonist, decreased the CSN discharges evoked by 0 and 7% O(2) by 30.8 and 72.5%, respectively. Suramin, a P(2)X antagonist, decreased the CSN discharges evoked by 0 and 7% O(2) by 64.3 and 17.1%, respectively. Simultaneous application of both antagonists strongly inhibited CSN discharges elicited by both hypoxic intensities. ATP release by CB increased in parallel to hypoxia intensity while adenosine release increased preferably in response to mild hypoxia. We have also found that the lower the O(2) levels are, the higher is the percentage of adenosine produced from extracellular catabolism of ATP. Our results demonstrate that ATP and adenosine are key neurotransmitters involved in hypoxic CB chemotransduction, with a more relevant contribution of adenosine during mild hypoxia, while vesicular ATP release constitutes the preferential origin of extracellular adenosine in high-intensity hypoxia.