Abnormal kinetics of erythrocyte sodium lithium countertransport in patients with diabetic nephropathy in Thailand.

BACKGROUND: In essential hypertension and diabetic nephropathy, sodium-lithium counter transport (Na/Li CT) is an inherited marker for metabolic influences of cardiovascular risk. The kinetics of Na/Li CT are modified by two types of thiol group in the membrane. In choline medium, the type 1 thiol reacts with N-ethtyl maleimide (NEM) to cause a decrease in Km and increase Vmax/Km ratio. However in the presence of external Na or Li both the type 1 or type 2 thiols react so that both Km and Vmax are reduced. Low Km of Na/Li CT has been previously reported to be a major abnormality in diabetic nephropathy (DN) and can be used to identify diabetic patients who are at high risk for DN. A recent study showed that the type 1 thiol protein controlling the Km of Na/Li CT was a 33-kD protein and the gene for this protein is going to be cloned. OBJECTIVE: The authors sought to identify Na/Li CT kinetic abnormalities in Type 2 diabetes in Thai patients. MATERIAL AND METHOD: Erythrocyte Na/Li CT kinetics and their modulation by thiol proteins were measured in erythrocytes from 22 patients with Type 2 diabetes and 42 normal control subjects. RESULTS: The kinetics of Na/Li CT in untreated erythrocytes were similar Thiol protein alkylation with NEM generally caused both Vmax and Km to fall, but caused Km to rise in erythrocytes of diabetic patients, whose native Km was low. Thus, abnormalities in the regulation of Na/Li CT by key thiol proteins were found in about one-third of subjects with Type 2 diabetes in Thailand. CONCLUSION: Membrane abnormalities may indicate a common pathway of pathological mechanism found in essential hypertension and diabetic nephropathy and may be used as a phenotype for further genetic studies of this transporter.

Factors associated with complications and adequacy of percutaneous kidney biopsy.

Objective: Percutaneous kidney biopsy (PKB) is an essential procedure in practical nephrology. However, it may cause serious complications, especially in high-risk patients. To determine the factors associated with the complications and the adequacy of PKB under ultrasonic guidance. Methods: Patients were stratified according to serum creatinine (SCr) and randomized for needle types (spring-loaded automatic gun and Tru-cut needle), diameters (16G vs 18G) and the effect of compression at biopsy site. The patients were observed for major (bleeding requiring a blood transfusion or intervention) and minor (not requiring intervention) complications. Results:The patients with serum creatinine (SCr) < 4.0 mg/dl (n=133) had significantly lower complications than those with SCr  4.0 mg/dl (n=35), both major (2 [1.5%] vs. 5 [14.3%]) and minor (6 [4.5%] vs. 3 [8.5%]). All complications occurred within 48 hours (93.8% within 24 hours). In group A, no significant difference in complications was found in needle types, axes, diameters and compression at the biopsy site, including numbers of puncture (< 6 times), length of tissue, kidney size and echogenicity. All samples except two were adequate for diagnosis, with an average of 13 glomeruli. There was no significant difference in tissue adequacy ( 10 glomeruli) in needle types and diameters, but the failure rate and number of puncture were higher with the Tru-cut needle (p < 0.01). Conclusion: The needle type and size or compression at the puncture site do not affect the complication after PKB under ultrasonic guidance, whereas a SCr 4.0 mg/dl is an important factor of the complications but there is no effect on the adequacy of the renal tissues.

Urinary citrate excretion in normal adults.

For 60 healthy subjects, aged 18-48, the urinary citrate excretion was studied by enzymatic method of Toftegaard Nielsen. The mean values in 24hr. urine were 1.44+0.61 mmole/day, 1.33+0.54 mmole/l. and 1.80+1.06 mmole/gm Cr, respectively. In single voided urine specimens, urinary citrate concentrations were 1.44+0.74 mmole/l and 1.82+0.98 mmole/gm Cr. Females had a higher mean value than males. There was no significant difference in the concentration of citrated excreted in different periods of the day when the excretion was expreesed as mmole per gram of creatinine, but when expressed in mmole per litre, the 10 pm-6 am period was different from others. The concentration of excreted citrate in each period correlated well with the 24 hour excretion, especially when it was expressed as mmole per litre (corr. Coeff. 0.55-0.9). Therefore, a single voided specimen can be used in the evaluation of total daily citrate excretion.

Non-oliguric renal failure in aminoglycoside nephrotoxicity.

Clinical and laboratory data were reviewed on 35 patients with acute renal failure associated with aminoglycoside administration. The diagnosis of nephrotoxicity was based on azotaemia both with or without a decline in the volume of urine. Clinical nephrotoxicity in these cases most likely occurred in association with surgery, advanced age, diabetes mellitus, jaundice and recent exposure to aminoglycosides. Twenty one of the 35 patients were non-oliguric. The duration of established renal failure after administion of aminoglycosides varied from 4 to 16 days. The common causative drugs were gentamicin (1.5-5 mg/kg/day) and kanamycin (1 gm/day) respectively. The maximum creatinine was 15 mg/dl. Conservative management of renal failure included withdrawal of aminoglycosides or adjusting the dose according to renal function, treatment of underlying diseases and provision of adequate hydration. Sixteen patients improved with normal serum creatinine within 7 days to 2 months after the onset of renal failure. Non of non-oliguric patients required dialysis treatment. Five patients died from septicaemia.