Expression and ultrastructural localization of HMB-45 antigen

HMB-45 is a monoclonal antibody specific for melanoma cells and premature developing melanocytes. We examined the expression and specific subcellular binding sites of HMB-45 in various types of melanocytes including epidermal melanocytes from fetuses and infants with or without tyrosinase-negative oculocutaneous albinism (type IA), melanin-producing and non-producing melanoma cell lines (G361 and MeWo), and in vivo melanoma cells (melanotic and amelanotic malignant melanoma). Subcellular HMB-45 binding was examined by using post-embedding immunogold electron microscopy with rapid freezing and freeze substitution fixation methods without the use of chemical fixatives to preserve the intracytoplasmic delicate antigen property of HMB-45. HMB-45 antigen was detected not only in in vivo melanoma cells and normal fetal melanocytes, but also in melanocytes in the other conditions. Post-embedding immunogold electron microscopy revealed that HMB-45 antigen was exclusively localized to stages I and III melanosomes in the melanocytes from fetuses and infants. In tyrosinase-negative oculocutaneous albinism, only stages I and II melanosomes were detected in the cytoplasm, but both stages of melanosomes were HMB-45 positive. We conclude that HMB-45 appears mainly on the immature melanosomes during melanogenesisin both neoplastic and non-neoplastic melanocytes regardless of their tyrosinase activity, but the intracytoplasmic localization of HMB-45 antigen is different by each condition of melanocytes.     

Insertion of a pacing lead via the tricuspid valve does not affect cardiac function and tricuspid valve regurgitation in young dogs

A preliminary experimental study in dogs was conducted to evaluate the feasibility of transvenous cardiac pacing in the fetus with complete heart block associated with hydrops. Four young mongrel dogs were anesthetized with intravenous administration of sodium pentobarbital and mechanically ventilated, and a pacing lead was inserted via the tricuspid valve. The right ventricular cardiac output, aortic pressure and central venous pressure were measured, and the tricuspid valve regurgitation was measured semi-quantitatively using echo-Doppler color flow imaging. The relationship between the location of the pacing lead and the tricuspid valve regurgitation and cardiac function was examined. The mean right ventricular cardiac output when the pacing lead was inserted into the superior vena cava (126 ± 54 mL/min per kg) was not significantly different from that when it was inserted into the right ventricle (110 ± 43 mL/min per kg). The aortic pressure was 66 ± 7.7 mmHg and 67 ± 6.6 mmHg, respectively, and the central venous pressure 5.9 ± 1.7 mmHg and 5.7 ± 1.6 mmHg, respectively, under the two conditions (not significantly different). The ratio of demonstrating significant tricuspid valve regurgitation was 4/13 into the superior vena cava and 5/13 into the right ventricle, respectively (not significantly different). The location of the pacing lead did not change the cardiac function or the amount of the tricuspid valve regurgitation in our experimental study. It was therefore concluded that the transvenous cardiac pacing technique has potential application in intrauterine transvenous cardiac pacing in the fetus with complete heart block.     

Testicular cancers occurring in brothers with cryptorchism

We report a case of familial testicular cancer associated with undescended testes in two brothers. The older brother (49 years) presented with a testicular tumor located in the right inguinal canal. The pathologic diagnosis was pure seminoma. Computerized tomography revealed iliac and retroperitoneal lymph node metastases. Four years later, the younger brother (44 years) developed bilateral testicular tumors, one located in the inguinal canal, the other located in the pelvic cavity. The pathologic diagnosis of both tumors was pure seminoma. Radiological examination revealed retroperitoneal lymph node metastases. Both patients received cisplatin-based combination chemotherapy as the initial treatment. The older brother suffered from repeated recurrences with lymph node metastases in the iliac and inguinal regions, but he was successfully treated with high-dose chemotherapy. The younger brother achieved long-term remission after retroperitoneal lymph node dissection following initial chemotherapy. We briefly review the reported cases of familial testicular cancer and discuss the association of the maldescent of the testes and familial testicular cancer cases.     

Ectopic Posterior Lobe of the Pituitary Gland and Intractable Nocturnal Enuresis in a Case with Pituitary Dwarfism

ABSTRACT. An 11 5/12-year-old girl with pituitary dwarfism had intractable nocturnal enuresis. Magnetic resonance imaging revealed pituitary stalk transection and the formation of an ectopic posterior lobe. The results of responses to dehydration, infusion of hyperosmolar NaCI solution, and l-desamino-8-D-arginine vasopressin showed that the nocturnal enuresis in the present case was due to a partial vasopressin deficiency. We suggest that the ectopic posterior lobe is one cause of nocturnal enuresis.     

Long-term effects of bone marrow transplantation for inborn errors of metabolism: A study of four patients with lysosomal storage diseases

Long-term effects of bone marrow transplantation (BMT) were evaluated in patients with I-cell disease, metachromatic leukodystrophy (MLD), Maroteaux-Lamy syndrome or Hunter syndrome (mild form). Donors were human leukocyte antigen (HLA)-matched siblings, and the follow-up periods were 24–71 months after BMT. The enzyme activities were increased in leukocytes, plasma or liver tissues compared with pre-BMT levels. A patient with I-cell disease acquired development of 4–8 month old infants and showed no further progression in cardiac dysfunctions. A patient with MLD showed a decelerated disease progression and an improved peripheral neuropathy, but progressive brain atrophy was not prevented. Patients with Maroteaux-Lamy syndrome or Hunter syndrome showed improvements in hepatomegaly, joint contractures, short stature and tight skin, and this greatly increased their quality of life. These results indicated that the long-term therapeutic effects achieved by BMT were subject to multiple factors including biochemical improvements, a reversibility of affected tissues, or advanced states of disease and central nervous system impairments in inborn errors of metabolism.