Dengue virus type 2, a member of the family Flaviviridae, encodes a single polyprotein precursor consisting of 3391 amino acids residues that is processed to at least 10 mature proteins by host and viral proteases. The NS3 protein contains a domain commonly found in cellular serine proteinases that in cooperation with NS2B is involved in polyprotein processing. In addition, NS3 and NS5 proteins contain conserved motifs found in several RNA helicases and RNA-dependent RNA polymerases, respectively. Both enzymatic activities have been suggested to be involved in viral RNA replication. In this report, we demonstrate that the NS3 and NS5 proteins interact in vivo in dengue virus type 2-infected monkey kidney (CV-1) cells and in HeLa cells coinfected with recombinant vaccinia viruses encoding these proteins as shown by coimmunoprecipitations and immunoblotting methods. We also show by immunofluorescence, metabolic labeling, and two-dimensional peptide mapping that NS5 is a nuclear phosphoprotein and that phosphorylation occurs on serine residues at multiple sites. Furthermore, NS5 exists in differentially phosphorylated states in the nuclear and the cytoplasmic fractions, and only the cytoplasmic form of NS5 is found to coimmunoprecipitate with NS3, suggesting that differential phosphorylation may control the interaction between these proteins and its function in the viral RNA replicase.

Loss of mitochondrial membrane potential (ΔΨm) triggers dramatic structural changes in mitochondria from a tubular to globular shape, referred to as mitochondrial fragmentation; the resulting globular mitochondria are called swelled or ring/doughnut mitochondria. We evaluated the early period of structural changes during the ΔΨm loss-induced transformation after carbonyl cyanide m-chlorophenyl hydrazine (CCCP) administration using a newly developed correlative microscopic method combined with fluorescence microscopic live imaging and volume electron microscopy. We found that most mitochondria changed from a tubular shape to a globular shape without fusion or fission and typically showed ring shapes within 10 min after CCCP exposure. In contrast, most ring mitochondria did not have a true through hole; rather, they had various indents, and 47% showed stomatocyte shapes with vase-shaped cavities, which is the most stable physical structure without any structural support if the long tubular shape shortens into a sphere. Our results suggested that loss of ΔΨm triggered collapse of mitochondrial structural support mechanisms.

To investigate the effect of matrix-degrading enzymes on the malignant potential of oral squamous cell carcinoma, the expression of matrix metalloproteinase-2 (MMP-2/72-kD gelatinase/type IV collagenase) in 46 patients who had neck surgery for oral cancer was studied immunohistochemically. In 20 of 26 patients (76.9%) with lymph node metastases, proMMP-2 was strongly expressed, whereas the production of proMMP-2 in tissue was detected only in 5 of 20 patients (25%) who had no lymph node metastases. In tissue specimens, proMMP-2 was expressed in a diffuse invasive mode and in the advancing front of cancer. Because MMP-2 can degrade type IV collagen composed of basement membrane, these results suggest that the in vivo production of the enzyme by cancer is an indicator of the degree of malignancy, and that the analysis of proMMP-2 expression is useful to evaluate the malignant potential in individual oral squamous cell carcinoma.

Background. Matrix metalloproteinases (MMP) are a gene family of zinc enzymes capable of degrading almost all of the extracellular matrix macromolecules in vivo. Their enzymic activities are believed to be responsible for tumor invasion and metastasis. Methods. In this study, using peroxidase‐antiperoxidase method, monospecific antisera against MMP‐1 (tissue collagenase), MMP‐2 (type IV collagenase/72‐kilo‐dalton [KD] gelatinase), and MMP‐3 (stromelysin) were applied to 29 squamous cell carcinomas and normal epithelium of the esophagus to identify cells synthesizing and secreting these enzymes. Results. Immunoreactivity of MMP‐1, −2, and −3 was observed in small cancer nests of the deeply invasive or marginal portion of the tumor. Among the 29 patients studied, the presence of at least one MMP was observed in 17 (58.6%). All three enzymes were observed in six (20.6%) patients, MMP‐2 and −3 in five (17.2%) patients, only MMP‐2 in three (10.3%) patients, and MMP‐3 alone in three (10.3%) patients. There was a good correlation among histologic stage and tumor invasion, lymph node metastasis, and MMP expression. In particular, expression of MMP‐2 and −3 was closely related to lymph node metastasis and vascular invasion. Conclusions. These results suggest that MMP, especially MMP‐2 and −3, play an important role in tumor invasion and metastasis and that analysis of MMP‐2 and −3 production is useful for evaluation of malignant potential in esophageal carcinoma. Cancer 1992; 702747–53.

Recent studies investigating accessory mental foramina using developments in diagnostic imaging have primarily defined the morphology of the foramina; however, few studies have described the structures passing through them. Additional clinical knowledge of the foramina is therefore required for preoperative diagnosis prior to surgery, including implant, periodontal and periapical surgery. In this study, we investigated the accessory mental foramina and the associated nerves and arteries in donated cadaveric mandibles using anatomical and radiological observation methods. We examined 63 mandibles with overlying soft tissue by cone-beam computed tomography and noted the existence of the accessory mental foramina. Mandibles with accessory mental foramina were subsequently analyzed. Additionally, the neurovascular bundles passing through these foramina were dissected using anatomical methods.The incidence of accessory mental foramina was 14.3%. The larger foramina tended to be located anteriorly or superiorly and proximal to the mental foramen, while the smaller foramina tended to be located posterosuperiorly and distal to the mental foramen. The mental foramen ipsilateral to the accessory mental foramen was smaller than the one contralateral to it. The comparatively distant and large accessory mental foramen included an artery.This study elucidated the relationship between accessory mental foramina and the associated nerves and arteries. We believe that the results will contribute to the clinical dentistry field.