Biomedical subjects

Yoko Santo

Publications and source records attributed to Yoko Santo.

6 recordsLinked to original sources

PubMed2006

Lack of puberty despite elevated estradiol in a 46,XY phenotypic female with Frasier syndrome.

Frasier syndrome is characterized by slowly progressive nephropathy, male pseudohermaphroditism, streak gonad, and high risk of gonadoblastoma development. Here we report a case of a 46,XY phenotypic female with Frasier syndrome, who was under hemodialysis. While her serum estradiol level was gradually increasing annually, gonadotropin level was constantly extremely high, and her appearance was still prepubertal. She was heterozygous for a novel guanine>adenine point mutation at position +1 of the splice donor site within intron 9 (IVS 9 + 1G>A) of the Wilms' tumor 1 gene. The possibility of this disease should be taken into consideration whenever we encounter a patient with steroid-resistant nephrotic syndrome and delayed puberty.

Adolescent↗

PubMed2005

Successful stenting for renal artery stenosis in a patient with Alagille syndrome.

A 12-year-old girl with Alagille syndrome manifested severe hypertension caused by renal artery stenosis in a solitary functioning kidney. Percutaneous transluminal angioplasty (PTA) and stenting was performed, but the hypertension persisted. On the next day, acute renal failure occurred with the administration of angiotensin-converting enzyme inhibitor, and migration of the stent was confirmed by angiography. Thus, a second stent was placed with success. Since then, the hypertension has been controlled with anti-hypertensive medication, and the renal function has recovered to normal range.

Alagille Syndrome↗

PubMed2004

Examination of megalin in renal tubular epithelium from patients with Dent disease.

Dent disease is characteristic for the urinary loss of low-molecular-weight proteins and calcium, leading to renal calcification and, in some patients, chronic renal failure. This disorder is caused by loss-of-function mutations in the renal chloride channel gene, CLCN5. The animal model of this disease has demonstrated the possible role of disturbed megalin expression, which is a member of the low-density lipoprotein receptor family and is associated with renal reabsorption of a variety of proteins, in Dent disease. We examined the expression of megalin in the renal tubular epithelium of two unrelated patients with Dent disease. One patient, whose CLCN5 gene was completely deleted, showed significantly decreased staining of megalin compared with controls, while there was no change in another patient with partial deletion of the gene. These results demonstrated that mutation of CLCN5 in some patients with Dent disease may impair the expression of megalin, resulting in abnormal calcium metabolism, manifested as hypercalciuria and nephrocalcinosis.

Calcium Metabolism Disorders↗

PubMed2003

Long-term hospitalization during pregnancy is a risk factor for vitamin D deficiency in neonates.

In order to examine the effects of long-term hospitalization during pregnancy on vitamin D metabolism in pregnant women and neonates, we measured the serum 25-hydroxyvitamin D (25OHD) levels in pregnant women, as well as measuring 25OHD levels in cord blood and breast milk. In pregnant women hospitalized for longer than 1 month, the serum 25OHD levels were decreased at delivery compared with those in control subjects (10.9 +/- 2.6 ng/l vs 19.5 +/- 4.9 ng/l; P < 0.01). Although the levels of 25OHD in the cord blood were not significantly different between the long-term hospitalized and control pregnant women in this study (9.36 +/- 1.7 ng/l vs 11.1 +/- 3.0 ng/l), the 25OHD concentrations in the cord blood were significantly lower than the maternal levels in both groups; the ratios of the levels in cord blood to sera in the long-term hospitalized women and control subjects were 82.1% and 60.3%, respectively. Long maternal hospitalization does not always cause neonatal vitamin D deficiency, but could be one of its major risk factors. Therefore, sufficient sunlight exposure and intake of sufficient vitamin D are considered to be important to prevent vitamin D deficiency in long-term hospitalized pregnant women as well as their babies.

Adult↗

PubMed2003

[A case of Denys-Drash syndrome with prophylactic bilateral nephrectomy].

Denys-Drash syndrome is a rare disorder consisting of pseudohermaphrodism, Wilms' tumor and nephropathy. We describe here a boy with severe hypospadias and undescended testes, who presented with end-stage renal failure at the age of 1 year and 8 months when he was referred to our hospital. Emergency hemodialysis was performed because of oliguria, edema and severe hypertension, and then peritoneal dialysis was started. The findings of the renal biopsy showed diffuse mesangial sclerosis, consistent with the characteristic change in Denys-Drash syndrome. The analysis of WT1 gene revealed a G-to-A point mutation at 1,186 resulting in a change from Asp to Asn at 396 in exon 9. Since he had no urine output and his kidneys were not functional and in addition, patients with this mutation have been reported to have a high risk of Wilms' tumor, bilateral nephrectomy was performed. The removed kidneys showed no malignancies. Since Denys-Drash syndrome is frequently associated with Wilms' tumor, renal biopsy and gene analysis should be performed on male patients with gonadal anomaly, such as hypospadias and/or undescended testes, and proteinuria.

Denys-Drash Syndrome↗

PubMed2003

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Journal Article↗