Determination of the apolipoprotein E genotype using PCR-RFLP in kidney diseases.

Using polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP), genotypes of the apolipoprotein E (Apo E) were determined in 50 control subjects and 60 Thai kidney diseases patients including nephritic syndrome and chronic renal failure (CRF) (30 each). Exon 4 of the Apo E genomic DNA was amplified between nucleotide numbers 2849 and 3071 (270 base pairs) then digested with HhaI. It is observed that E3/3 was the most common genotype found in the control subjects (80%). In nephritic syndrome patients, E4/3 was found to be the most frequent (53.3%). On the contrary, E3/3 was found to be the most prominent in CRF patients (80%). There was a significant different of the Apo E genotype in hephrotic syndrome from the normal control subjects (p < 0.05 by X2 analysis). One the other hand, there was no significant difference of the Apo E genotype in CRF patients from the control subjects (p>0.5). Cholesterol and triglyceride levels of the E4/3 nephrotic syndrome patients were significantly different from the normal controls of the same genotype (p<0.05). Similarly, in CRF patients, triglyceride level of the E3/3 genotype was also significantly different from the normal controls of the same genotype (p<0.05). These results suggested that polymorphism of the Apo E genotypes may be associated with the lipid abnormalities in renal diseases.

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.