Yuko Abe

Ultrasound Grade of Hydronephrosis and Severity of Renal Cortical Damage on 99mTechnetium Dimercaptosuccinic Acid Renal Scan in Infants With Unilateral Hydronephrosis During Followup and After Pyeloplasty

PURPOSE We performed ultrasonography and (99m)technetium dimercaptosuccinic acid (DMSA) renal scan in infants with unilateral hydronephrosis during followup and after pyeloplasty to examine the correlation of ultrasound hydronephrosis grade with the severity of renal cortical damage and assess the recovery of renal function in the obstructed kidneys after surgery. MATERIALS AND METHODS We studied 80 boys and 19 girls with unilateral hydronephrosis detected in the first year of life, including 75 (76%) in whom it was detected prenatally. Ultrasound images were graded according to the Society for Fetal Urology grading system. The severity of renal cortical damage was assessed by DMSA renal scan. Absolute function of the right and left kidneys was estimated by DMSA uptake and relative DMSA uptake was calculated by the formula, relative uptake = uptake in obstructed kidney/total uptake in right and left kidneys x 100%. RESULTS On ultrasonography grades 1 to 4 hydronephrosis were diagnosed in 9, 21, 19 and 50 kidneys, respectively. On DMSA renal scan cortical damage was detected in 10 kidneys (53%) with grade 3 and 49 (98%) with grade 4 hydronephrosis but not in kidneys with grade 1 or 2 disease. Dysfunction in the obstructed kidney, defined as relative DMSA uptake less than 40%, was noted in 13 patients with grade 4 hydronephrosis. Relative DMSA uptake significantly increased after successful pyeloplasty compared with preoperative uptake (44% +/- 2% versus 40.1% +/- 2%, p <0.01). CONCLUSIONS Ultrasound grading of hydronephrosis correlates with the severity of cortical damage or the decrease in renal function on DMSA renal scan. Differential renal function on DMSA renal scan may be a useful and less invasive tool for determining surgical indications and examining changes in renal function after surgery.

Emergence of fluoroquinolone-resistant Streptococcus pyogenes in Japan by a point mutation leading to a new amino acid substitution

OBJECTIVES Streptococcus pyogenes causes various diseases in humans. While the prevalence of fluoroquinolone-resistant S. pyogenes isolates has been increasing since 2000 in the USA and Europe, it has remained very low in Japan. We isolated a fluoroquinolone-resistant S. pyogenes strain and analysed its genetics. METHODS TU-296, a strain of S. pyogenes resistant to levofloxacin (MIC 16 mg/L), was isolated from the throat of a patient in their thirties with pharyngitis in autumn 2007. We carried out susceptibility tests for various antimicrobial agents and PCR analysis of the genes gyrA, gyrB, parC and parE in the quinolone resistance-determining region, followed by sequencing of the PCR products to find mutation(s) and the resulting amino acid substitution(s). We then sequenced the PCR product of the emm gene and determined the emm genotype. RESULTS S. pyogenes TU-296 was found to have the following mutations and amino acid substitutions: adenine 476 to cytosine in gyrA and cytosine 367 to thymine in parC, resulting in Glu-85→Ala in GyrA and Ser-79→Phe in ParC. The genotype of the isolate was emm11. CONCLUSIONS Amino acid substitutions in fluoroquinolone-resistant S. pyogenes have already been reported from Europe and the USA, including Ser-81→Phe or Tyr and Met-99→Leu in GyrA, as well as Ser-79→Phe, Tyr or Ala and others in ParC. Numerous point mutations were found in parC and parE of S. pyogenes TU-296. In addition, a new amino acid substitution was detected (Glu-85→Ala in GyrA). To our knowledge, there have been no previous reports of this substitution in a clinical isolate of S. pyogenes.

Urinary Excretion of Vascular Endothelial Growth Factor Is Increased in Children with Reflux Nephropathy

Background: We determined the urinary levels of vascular endothelial growth factor (VEGF) in patients with reflux nephropathy to elucidate its clinical significance as a predictor of the development of renal damage. Patients and Methods: Seventy-two patients (47 boys and 25 girls) aged 10–18 years with reflux nephropathy were studied. Vesicoureteral reflux was resolved surgically in all cases at least 2 years before enrollment. Urinary VEGF, α1-microglobulin and albumin levels were determined using morning spot urine samples. Plasma VEGF, serum creatinine and β2-microglobulin levels were measured simultaneously. The severity of renal scarring and right and left kidney function were assessed by 99mTc dimercaptosuccinic acid renal scan. Results: No significant correlation was found between the plasma and urinary VEGF levels. Urinary VEGF increased significantly with the increase in severity of renal scarring (p < 0.0001). Urinary VEGF levels correlated significantly with serum β2-microglobulin (p < 0.002) and urinary α1-microglobulin (p < 0.03). No significant correlation of urinary VEGF levels with serum creatinine and urinary albumin levels was found. Nearly 60% of the patients with elevated urinary VEGF had normal levels of serum β2-microglobulin and/or urinary α1-miocroglobulin. Conclusions: Urinary VEGF level appears to reflect its production in the kidney. Since urinary VEGF shows a propensity to elevate before the increase in serum β2-microglobulin and/or urinary α1-microglobulin, urinary VEGF may serve as an early indicator of the development of reflux nephropathy.