Axial heterogeneity and filtered-load dependence of proximal bicarbonate reabsorption

A theoretical model was developed to examine the role of physical and chemical factors in the control of bicarbonate reabsorption in the renal proximal tubule. Included in the model were axial and radial variations in the concentrations of HCO3-, CO2 and related chemical species in the tubule lumen and epithelial cells. Relations between these concentrations and the solute fluxes across the brush border and basolateral membranes were also included, as were reaction rate and equilibrium expressions to describe the various buffering processes in the lumen and cells. The two most critical membrane parameters, the rate constant for H+ secretion at the brush border and the effective permeability of HCO3- at the basolateral membrane, were evaluated by comparing model predictions with available free-flow micropuncture data in the rat. It was found that the experimental observations could be explained only by decreasing one or both of these membrane parameters with axial position, suggesting a progressive decrease in HCO3- reabsorptive capacity along the tubule. For single nephron filtered loads of HCO3- up to about 1,400 pmol/min, absolute bicarbonate reabsorption was predicted to increase nearly in proportion to filtered load, whereas it was calculated to be relatively constant at higher filtered loads, irrespective of how filtered load was assumed to be varied. These predictions are in excellent agreement with most of the available micropuncture data in rats, as is the prediction that HCO3- reabsorption should change in parallel with CO2 partial pressure in the filtrate, at a given filtered load of HCO3–. Certain discrepancies between the model predictions and experimental observations are evident at very high filtered loads, and the implications of these are discussed in terms of possible adaptive responses of the tubule

Effect of device-guided breathing exercises on blood pressure in hypertensive patients with type 2 diabetes mellitus:A randomized controlled trial

Objective In patients with type 2 diabetes mellitus (DM2), it is hard to reach treatment objectives for blood pressure (BP) with classical treatment options. Recently, reducing breathing frequency has been advocated as a method to reduce BP. We examined if an electronic device such as Resperate, by reducing breathing frequency, would lead to BP reduction in a population of patients with DM2 and hypertension. Our secondary objective was to study the effect of this device on quality of life (QOL). Methods A randomized, single-blind, controlled trial was conducted over a period of 8 weeks to evaluate the effect of this therapy on BP and QOL. The control group listened to music and used no other therapeutic device. BP and QOL changes were studied in 30 patients with DM2 and hypertension. Results There was no significant difference in change in BP between groups; -7.5 [95% confidence interval (CI) -12.7, -2.3]/-1.0 (95% CI -5.5, 3.6) mmHg in the intervention group and -12.2 (95% CI -17.4, -7.0)/-5.5 (95% CI -9.7, -1.4) mmHg in the control group. Whether or not the target breathing frequency of 10 breaths/min was reached did not affect BP. There were no significant changes in QOL. Conclusions The effects of Resperate on BP and QOL were not significantly different from those found in the control group. Furthermore, 40% of patients did not reach the target breathing frequency, making this device less suitable for clinical practice in patients with DM2

Hypomagnesemia in persons with type 1 diabetes:associations with clinical parameters and oxidative stress

Background: Among persons with type 1 diabetes mellitus (T1DM) low concentrations of magnesium have been reported. Previous (small) studies also suggested a relation of hypomagnesemia with (poor) glycaemic control and complications. We aimed to investigate the magnitude of hypomagnesemia and the associations between magnesium with parameters of routine T1DM care in a population of unselected outpatients. Methods: As part of a prospective cohort study, initially designed to measure quality of life and oxidative stress, data from 207 patients with a mean age of 45 [standard deviation (SD) 12] years, 58% male, diabetes duration 22 [interquartile range (IQR) 16, 31] years and glycated haemoglobin (HbA1c) of 60 (SD 11) mmol/mol [7.6 (SD 1.0)%] were examined. Hypomagnesemia was defined as a concentration below Results: Mean magnesium concentration was 0.78 (SD 0.05) mmol/l. A deficiency was present in 4.3% of participants. Among these persons, mean concentration was 0.66 (SD 0.03) mmol/l. There was no correlation between magnesium and HbA1c at baseline (r = -0.014, p = 0.843). In multivariable analysis, free thiols (reflecting the degree of oxidative stress) were significantly and negatively associated with magnesium concentrations. Conclusion: In this cohort of T1DM outpatients, the presence of hypomagnesemia was infrequent and, if present, relative mild. Magnesium was not associated with glycaemic control nor with presence of micro- and macrovascular complications. Although these results need confirmation, in particular the negative association of magnesium with free thiols, this suggests that hypomagnesemia is not a relevant topic in routine care for people with T1DM

Type 2 diabetes seems not to be a risk factor for the carpal tunnel syndrome:a case control study

BACKGROUND: Previous studies have shown that the carpal tunnel syndrome seems to occur more frequently in patients with diabetes mellitus and might be associated with the duration of diabetes mellitus, microvascular complications and degree of glycaemic control. Primary aim was to determine if type 2 diabetes can be identified as a risk factor for carpal tunnel syndrome after adjusting for possible confounders. Furthermore, the influence of duration of diabetes mellitus, microvascular complications and glycaemic control on the development of carpal tunnel syndrome was investigated. METHODS: Retrospective, case-control study using data from electronic patient charts from the Isala (Zwolle, the Netherlands). All patients diagnosed with carpal tunnel syndrome in the period from January 2011 to July 2012 were included and compared with a control group of herniated nucleus pulposus patients. RESULTS: A total of 997 patients with carpal tunnel syndrome and 594 controls were included. Prevalence of type 2 diabetes was 11.5% in the carpal tunnel syndrome group versus 7.2% in the control group (Odds Ratio 1.67 (95% confidence interval 1.16-2.41)). In multivariate analyses adjusting for gender, age and body mass index, type 2 diabetes was not associated with carpal tunnel syndrome (OR 0.99 (95% CI 0.66-1.47)). No differences in duration of diabetes mellitus, microvascular complications or glycaemic control between groups were detected. CONCLUSION: Although type 2 diabetes was more frequently diagnosed among patients with carpal tunnel syndrome, it could not be identified as an independent risk factor

Gender differences in the evaluation of care for patients with type 2 diabetes:a cross-sectional study (ZODIAC-52)

BACKGROUND: Little is known about the association between patient-related factors and patients' evaluation of care. Aim was to investigate which patient-related factors are associated with patients' evaluation of care in men and women with type 2 diabetes (T2D) in primary care. METHODS: This cross-sectional study included 1102 patients with T2D from 52 general practices. We measured patients' evaluation with the EUROPEP questionnaire and collected demographic, clinical and psychological data from questionnaires and health records. Stepwise linear regression analyses were used. RESULTS: The location where the questionnaire was completed (at home or at the general practice) was associated with all outcomes in men and women. Next to this, in men, explanatory factors for the care provider EUROPEP subscale were use of insulin, having some problems with T2D self-care and coffee consumption (R2 8.4%); coffee consumption was associated with the general practice subscale (R2 4.0%). In women, well-being, quality of life, following a general diet, and use of oral glucose-lowering drugs were associated with the care provider subscale (R2 16.8%). For the general practice subscale, well-being and age were explanatory factors (R2 9.4%). CONCLUSIONS: Only a few factors were found to be associated with patients' evaluation of care for men and women with T2D. Taken together, these factors explained only a small part of the variance of the EUROPEP scores. This explained variance was largely attributable to the location where the questionnaire was completed. We therefore advise to be aware of the possible consequences of filing-out questionnaires about patients' evaluation of care at the general practice. TRIAL REGISTRATION: NCT01570140 (Clinicaltrials.gov). Registered 29 March 2012