Correlations between blood uric acid and the incidence and progression of type 2 diabetes nephropathy.

OBJECTIVE: To investigate the relationships between blood uric acid (BUA) level and the incidence, progression and deterioration of diabetic nephropathy (DN) in patients with type 2 diabetes mellitus (T2DM). PATIENTS AND METHODS: A total of fifty patients with T2DM alone whose glycosylated hemoglobin (HbA1c) were under normal range (4-6.5%) at their admission to our hospital were randomly selected as diabetes mellitus (DM) group. Fifty patients with hyperuricemia alone were randomly selected as hyperuricemia (HUA) group. Fifty patients with T2DM complicated with hyperuricemia who were admitted to the hospital with HbAlc of 4-6.5% were randomly selected as diabetes mellitus hyperuricemia (DM-HUA) group. In addition, fifty healthy persons who passed the health examination were randomly selected as normal control (NC) group. The general data such as name and body mass index (BMI), metabolic-related indexes such as fasting blood glucose (FBG), total cholesterol (TC) and triglyceride (TG) as well as kidney-related indexes such as blood urea nitrogen (BUN), creatinine (Cr) and albumin-creatinine-ratio (ACR) in four groups were tested and recorded at the same time. The interrelationships between uric acid (UA) and the above indexes were statistically analyzed. RESULTS: In DM-HUA group, serum TC, TG and low density lipoprotein (LDL) as well as urine ACE were greatly increased (p<0.05) compared with the other three groups, high-density lipoprotein (HDL) was significantly decreased compared with the remaining three groups (p<0.05), and BMI and Cr were increased compared with those in NC group and DM group (p<0.05). There were no significant differences in metabolic indexes and renal functions in DM group and HUA group. Compared with NC group, TC, LDL, serum ß2 macroglobulin and BMI in above two groups were greatly increased (p<0.05); BUN and Cr in HUA group were slightly higher than those in NC group (p<0.05). Multiple linear regression analysis showed that UA level was the main factor affecting ACR (R2=0.636, p<0.001). CONCLUSIONS: UA level is an independent risk factor for early renal disease in patients with T2DM, which can promote the progression and deterioration of renal disease in T2DM patients.

[Electrophysiological effects of calcitonin gene-related peptide on isolated sinoatrial node of the rabbit].

The purpose of this study was to investigate the electrophysiological effects of calcitonin gene-related peptide (CGRP) on the pacemaker cell of rabbit sinoatrial node (SAN) and to determine whether I(Ca) is involved in the effects. Action potentials (AP) were recorded from the isolated SAN with microelectrode technique. It was found: (1) CGRP (1 nmol/L) had no effect on AP configuration; CGRP (10 nmol/L) increased the maximal diastolic potential, AP amplitude and depolarization velocity of 0 and 4 phases, and decreased sinus cycle length and AP duration. After applying CGRP for 20 min the above effects reached to a maximum. (2) CGRP (100 nmol/L) caused arrhythmia in the SAN. (3) Calcium channel antagonists, CdCl2 and verapamil attenuated the electrophysiological changes in AP of SAN induced by CGRP (20 nmol/L). The results indicate that a calcium-dependent mechanism may underlie the CGRP effects.

[Refractory periods of cardiac tissues and the filtering properties of the atrioventricular node in the isolated rabbit heart].

It is generally believed that the atrioventricular node (AVN) possesses filtering properties (FP) capable of preventing excess atrial impulses or earlier atrial premature beat from reaching the ventricle. In the present study, the refractory periods (RP) of cardiac tissues and the FP of the AVN were investigated in isolated rabbit hearts (n = 18). It was found that: (1) The relative RP of AVN was the longest at shorter basic cycle lengths (BCL) (200-300 ms) while the relative RP of His-Purkinje system (HPS) was the longest at longer BCL (600, 700 ms). (2) The effective RP of AVN was shorter than the functional RP of the atrium in most cases (16/18) at any BCL. (3) During rapid atrial pacing at cycle length of 140 ms in 7 cases, AVN maintained 1:1 conduction. (4) The atrioventricular nodal conduction curve was smooth at BCL from 200 to 700 ms. The present results suggest that AVN in the isolated perfused rabbit heart do not have the FP and any dual atrioventricular pathways in a physiological sense.