Immature renal tubules are more tolerant to ischemia than mature renal tubules. Here we compared the developmental pattern for some cellular responses evoked by hypoxia and reoxygenation in renal proximal tubules from 10- and 40-day-old rats. Redistribution of Na(+)-K(+)-ATPase from the plasma membrane was studied by confocal microscopy techniques in primary cultured renal proximal tubular cells. The developmental expression of Na(+)-K(+)-ATPase, micro-calpain and heme oxygenase-1 was measured by RT-PCR techniques in rat renal cortex. In response to hypoxia Na(+)-K(+)-ATPase redistribution from the plasma membrane was almost 2-fold increased in cells isolated from mature kidneys compared with cells isolated from immature kidneys. Reoxygenation resulted in a complete reestablishment of Na(+)-K(+)-ATPase in the plasma membrane in the immature but not in the mature cells. The dissociation of Na(+)-K(+)-ATPase from the plasma membrane was associated with a reduced activity and a reduced expression of Na(+)-K(+)-ATPase in the mature but not in the immature tubular cells. The expression of micro-calpain, a factor shown to induce ischemic injury to proximal tubular cells, was significantly lower in the immature compared with the mature kidney, whereas the expression of heme oxygenase-1, a factor shown to protect from renal ischemic injury, was significantly higher in the immature kidney. The results help to explain the increased tolerance of the immature kidney to injury caused by ischemia and reperfusion.
We present the case of a 3-year-old girl with McCune-Albright Syndrome (MAS). She was referred to our clinic for mammary gland enlargement and vaginal bleeding. A right ovarian cyst was detected by abdominal MRI and pelvic ultrasound examination, and it was followed up as a functional cyst. Endocrine studies showed gonadotropin-independent precocious puberty. A bone scintigram, revealed polyostotic fibrous dysplasia. These data confirmed the diagnosis of MAS without skin pigmentation (café-au-lait spot). We treated the patient with the aromatase inhibitor, anastrozole (ArimidexR), because of repeated vaginal bleedings. After 6 mo of treatment, the frequency of vaginal bleeding was clearly decreased and the level of estradiol was down to within normal limits. The aromatase inhibitor, anastrozole, appears to be an effective treatment for precocious puberty caused by MAS.
Abstract Background: Monocarboxylate transporter 8 (MCT8) deficiency is an X- chromosome-linked neurodevelopmental disorder resulting from impaired thyroid hormone transporter across cell membrane. The diagnosis of MCT8 deficiency is typically delayed owing to the late appearance of signs and symptoms as well as inability of standard biomarkers of neonatal screening to make an early diagnosis. Here, we report for the first time the ability to identify MCT8 deficiency at birth using dried blood spot (DBS) samples. Methods: We measured T3, T4, and reverse T3 (rT3) levels in DBS samples obtained at birth in healthy neonates (n = 42) and neonates with genetically confirmed diagnosis of MCT8 deficiency (n = 6). T3, rT3 and T4 levels were measured in 8 mm diameter DBS samples using liquid chromatography-tandem mass spectrometry. Results: Mean ± SD level of T3 tended to be higher in the MCT8 group than that in healthy neonates (0.941 ± 0.183 ng/mL vs. 0.742 ± 0.195 ng/mL, p = 0.0525). More importantly rT3 level in the MCT8 group was significantly lower than that in healthy neonates (0.317 ± 0.065 ng/mL vs. 0.768 ± 0.196 ng/mL, p < 0.0001) and the T3/rT3 ratio in the MCT8 group was significantly higher (3.04 ± 0.67 vs. 1.01 ± 0.34, p < 0.0001) with no overlap of values. T4 was lower in the MCT8 group than in healthy babies (93.4 ± 22.4 ng/mL vs. 156.7 ± 35.9 ng/mL, p < 0.0005) and the T3/T4 ratio of the MCT8 deficient group was higher (0.0105 ± 0.0029 vs. 0.0051 ± 0.0010, p< 0.0001). Conclusion: rT3 and T3/rT3 ratio measured in the DBS obtained from neonates can serve as biomarkers for diagnosis of MCT8 deficiency at birth.
Background: Monocarboxylate transporter 8 (MCT8) deficiency is an X-chromosome-linked neurodevelopmental disorder resulting from impaired thyroid hormone transport across the cell membrane. The diagnosis of MCT8 deficiency is typically delayed owing to the late appearance of signs and symptoms as well as the inability of standard biomarkers of neonatal screening to provide early detection. In this study, we report, for the first time, the ability to detect MCT8 deficiency at birth using dried blood spot (DBS) samples. Methods: We retrospectively measured triiodothyronine (T3), thyroxine (T4), and reverse T3 (rT3) levels in DBS samples obtained at 4-5 days of life from 6 infants with genetically confirmed MCT8 deficiency and from 110 controls. The latter consisted of 58 healthy term neonates obtained at the same time, 16 were stored for more than 1 year before measurement to match samples from the MCT8-deficient infants. Ten DBS samples were collected at day 1 of life and 42 samples were from prematurely born neonates. Measurements were carried out in extract from eight millimeters diameter DBS using liquid chromatography-tandem mass spectrometry. Results: Contrary to characteristic iodothyronine abnormalities of MCT8 deficiency during later life, T3 and T4 values were not discriminatory from those of other study groups. In contrast, rT3 was significantly lower. The T3/rT3 ratio was higher in the DBS samples from the MCT8-deficient infants compared with all other groups with no overlap (p < 0.0001). Conclusions: rT3 and T3/rT3 ratio in DBS samples obtained from neonates can serve as biomarkers to detect MCT8 deficiency at birth.
Background: Monocarboxylate transporter 8 (MCT8) is a thyroid hormone transmembrane transporter protein. MCT8 deficiency induces severe X-linked psychomotor retardation. Previous reports have documented delayed myelination in the central white matter (WM) in these patients; however, the regional pattern of myelination has not been fully elucidated. Here, we describe the regional evaluation of myelination in four patients with MCT8 deficiency. We also reviewed the myelination status of previously reported Japanese patients with MCT8 deficiency based on magnetic resonance imaging (MRI). Case Reports: Four patients were genetically diagnosed with MCT8 deficiency at the age of 4–9 months. In infancy, MRI signal of myelination was observed mainly in the cerebellar WM, posterior limb of internal capsule, and the optic radiation. There was progression of myelination with increase in age. Discussion: We identified 36 patients with MCT8 deficiency from 25 families reported from Japan. The available MRI images were obtained at the age of <2 years in 13 patients, between 2 and 4 years in six patients, between 4 and 6 years in three patients, and at ≥6 years in eight patients. Cerebellar WM, posterior limb of internal capsule, and optic radiation showed MRI signal of myelination by the age of 2 years, followed by centrum semiovale and corpus callosum by the age of 4 years. Most regions except for deep anterior WM showed MRI signal of myelination at the age of 6 years. Conclusion: The sequential pattern of myelination in patients with MCT8 deficiency was largely similar to that in normal children; however, delayed myelination of the deep anterior WM was a remarkable finding. Further studies are required to characterize the imaging features of patients with MCT8 deficiency.
We report a 17 yr old male with short stature and delayed adolescence due to distorted body image. He was admitted to our hospital because of growth failure at the age of 15 yr 7 mo. His growth had been normal, but after entering a junior high school, he began to take an interest in physical exercise and protein diet. His endocrine data and psychopathological profiles such as eating, training pattern and extreme diet and failure to make expected growth and puberty were compatible with DSM-IV and ICD-10 criteria for the diagnosis of anorexia nervosa (AN). The symptoms of male AN are different from female AN and it is difficult to diagnose. We emphasize the necessity of considering AN in the differential diagnosis of growth retardation and delayed adolescence in young males.
