Activity of synthetic enzymes of tetrahydrobiopterin in the human placenta

Tetrahydrobiopterin (BH4) is an essential co-factor for nitric oxide (NO) synthase (NOS) and regulates the production of NO, or endothelium-derived relaxation factor. Although NOS is highly expressed in the placenta and NO plays a critical role in the regulation of feto-placental circulation, the mechanism maintaining the level of BH4 is not known. To investigate the de novo synthesis of BH4 in the human placenta, the activity of guanosine triphosphate cyclohydrolase I (GTPCH), 6-pyruvoyltetrahydropterin synthase (PTPS), and sepiapterin reductase (SR) in the chorionic tissue during the first, second and third trimester of pregnancy was analyzed. GTPCH activity was the lowest of the three enzymes and became negligible after the second trimester. There was no significant change in PTPS activity throughout pregnancy. Although SR activity decreased significantly after the second trimester, the levels remained abundant throughout pregnancy. These results showed that GTPCH is a rate-limiting enzyme and the total activity of the de novo synthesis of BH4 is negligible in the mature placenta after the second trimester when fetal growth is accelerated. The present study suggests that the level of BH4 in the placenta depends principally on the system other than de novo synthesis. The salvage pathway is considered the most potent system, which is formed by the transfer of the substrates from the fetus and their enzymatic conversion to BH4 in the placenta.     

Keratin in human lung tumors. Patterns of localization of different-molecular-weight keratin proteins.

In this immunohistochemical study, antiserums to different molecular weight keratin proteins (45kd, 46kd, 55kd, and 63kd) were utilized to determine the profiles of keratin proteins present in a variety of pulmonary neoplasms. Different histologic types of lung carcinoma exhibited different patterns of keratin staining. Squamous cell carcinomas stained strongly for 45K, 46K, and 55K keratin, with staining for 63K restricted to areas or individual cells with cytoplasmic keratinization. Adenocarcinomas showed variable, generally weak staining for 45K, 46K, and 55K keratin and were uniformly negative for 63K keratin both in frozen and paraffin sections. Mesotheliomas and reactive mesothelial cells, by contrast, stained positively for 63K keratin in addition to keratins of lower molecular weights. Differences in staining for 63K keratin between mesothelioma and adenocarcinoma may have diagnostic application. Moreover, individual cytokeratins may serve as markers of tumor differentiation and provide information as to the origin of neoplastic cells.     

Proliferative funiculitis with a prominent infiltration of mast cells

A surgical case of proliferative funiculitis (pseudosarcomatous myofibroblastic proliferation of the spermatic cord) with a prominent mast cell infiltration is reported. A 67-year-old man with a history of right inguinal herniorrhaphy 7 years earlier was operated on for diffuse swelling of the inguinal region and scrotum. A large lipoma was found in the inguinal region, and a nodular lesion, measuring 2.7 cm in maximal dimension, was firmly attached to the right spermatic cord. The nodular lesion showed diffuse proliferation of fibroblasts and myofibroblasts associated with the deposition of collagen. A diffuse infiltration of numerous mast cells was found throughout the lesion. Lesions that belong to the group of inflammatory pseudotumors are rarely accompanied by a prominent mast cell infiltration, and the differentiation from mast cell neoplasms is often problematic in such cases. The present case is the first example of proliferative funiculitis associated with this rare phenomenon.     

Malignant peripheral nerve sheath tumor of small round cell type with pleomorphic spindle cell sarcomatous areas

An unusual case of malignant peripheral nerve sheath tumor (MPNST) arising in the posterior mediastinum of a 59-year-old man is reported. Histopathologically, the tumor showed an admixture of a dense proliferation of small round cells resembling a primitive neuroectodermal tumor (PNET) and a pleomorphic spindle cell sarcomatous area. Abortive rosettes, primitive neural tube-like structures, and a few glandular structures were found in the small round cell area. Small round cells were immunoreactive for neural cell adhesion molecule and synaptophysin, but were not immunoreactive for MIC2 and neuron-specific enolase. Pleomorphic spindle cells were occasionally arranged in a storiform pattern and were diffusely immunoreactive for S-100 protein. The MPNST of small round cell type is distinguishable from PNET by its negative immunoreactivity for MIC2, and the present tumor is assumed to be derived from primitive neuroectodermal cells in the peripheral nerve capable of bidirectional (neuron and Schwann cell) differentiation.     

Generalized sarcoidlike granulomas with systemic angiitis, crescentic glomerulonephritis, and pulmonary hemorrhage. Report of an autopsy case

A 19-year-old woman showed rapidly progressive renal and respiratory failure and died after a short clinical course. The autopsy revealed that death was due to crescentic glomerulonephritis and pulmonary hemorrhage. The intrathoracic lymph nodes, lungs, kidneys, and other organs contained numerous epithelioid granulomas, some of which had foci of central coagulative necrosis. The aorta, its major branches, and small- to medium-sized vessels of various organs also had multiple areas of granulomatous angiitis. This is, to our knowledge, the first report of such autopsy findings. A discussion of the etiopathogenesis of the disease is presented.     

Cytomegalovirus vasculitis accompanied by an exuberant fibroblastic reaction in the intestine of an AIDS patient.

A case of cytomegalovirus (CMV) vasculitis in the intestine of a patient with acquired immune deficiency syndrome (AIDS) is reported. The distal jejunum and ileum had multiple well-demarcated mucosal ulcers and microscopic examination revealed an unusual, exuberant fibroblastic proliferation in the ulcer base. Amidst these fibroblasts, there were several small blood vessels of which the endothelial cells contained cytomegalic inclusion bodies. The lesion showed a Kaposi's sarcoma-like appearance, but spindle cells were negative in immunostaining for factor VIII-related antigen or Ulex europaeus agglutinin-1. Although the CMV infection was observed in almost all organs, the exuberant fibroblastic proliferation seen in the intestine was not found in other organs. This lesion might represent a peculiar reaction of the immunologically compromised host to the CMV in the intestinal blood vessels.     

Characteristics of incidentally detected renal cell carcinoma by ultrasonography at health check-up

BACKGROUNDS: The prognosis of patients with incidentally detected renal cell carcinoma is better than that of patients with symptomatic renal cell carcinoma. These incidentalomas include those discovered by ultrasonography at health check-up and those found during examinations for unrelated disease. In this study, we investigated the prognosis of the patients of the health check-up group and the unrelated disease group. METHODS: From April 1987 to March 1997, 263 patients with renal cell carcinoma were treated in our department including 166 incidentalomas (63.1%). The occasion of incidental detection was divided into 2 groups; 90 cases as health check-up group and 76 cases as unrelated disease group. RESULTS: The mean age was 52.9 +/- 9.7 years for health check-up group and 65.1 +/- 11.4 years for unrelated disease group (p < 0.01). The mean evaluated tumor size was 3.6 +/- 1.6 cm for health check-up group and 4.4 +/- 2.6 cm for unrelated disease group (p < 0.05). The survival rates were significantly different in the two groups (p < 0.01); the 5- and 10-year survival rate for health check-up group was 91.5% and 55.9%, respectively and for unrelated disease group 79.4% and 66.1%, respectively. CONCLUSION: These results suggested that examination by ultrasonography at health check-up lead to detection of smaller renal cell carcinoma and improve the prognosis further.