Aluminum Foam, “Alporas”: The Production Process, Properties and Applications

The production of foamed aluminum has long been considered difficult to realize because of such problems as the low foamability of molten metal, the varying size of cellular structures, solidification shrinkage and so on. Recently these problems have been solved by a number of researches and some manufacturers produce foamed aluminum by their own methods. We have been employing a batch casting process and manufacturing foamed aluminum under the tradename ALPORAS® since 1986. This paper presents the manufacturing process, physical properties and some typical applications of ALPORAS.

Relationship between tooth contacts in the retruded contact position and mandibular positioning during retrusion

We conducted a series of studies with the purpose to investigate the locations of tooth contacts in the retruded contact position (RCP) and to discuss their significance in the stomatognathic system. In the present study, the relationship between the locations of RCP contacts and mandibular positioning during retrusion was examined. Thirty dentists and clinical residents were selected as subjects. One specialist in prosthetic dentistry examined each subject for the location of the RCP contacts. The mandibular positioning during retrusion was measured using a mandibular movement analysis system with six degrees of freedom. Originally programmed software was developed. Five reference points were selected: the central lower incisor (point I), the first molars on both sides (points RM and LM) and the condyles on both sides (points RC and LC). Tooth contact was observed most frequently at the second molar, followed by the first premolar. Points I, RM and LM all moved in an inferior-posterior direction, whereas points RC and LC moved in various directions ranging from superior-posterior to inferior-posterior. When the subjects were divided into two groups according to the most anterior tooth of occlusion in the RCP, the condylar positioning tended to be more superior in the group with molar contact than that with premolar contact. These results suggest that the locations of RCP contacts could be an important factor in jaw guidance during retrusion.

Relationship of periodontal bacteria and Porphyromonas gingivalis fimA variations with phenytoin-induced gingival overgrowth

OBJECTIVES

We investigated the relationship between phenytoin-induced gingival overgrowth (GO) and the harboring of periodontal bacteria.

MATERIALS AND METHODS

Periodontal conditions and subgingival bacterial profiles were examined in 450 sites of 75 subjects. A polymerase chain reaction method was used to detect six bacterial species; Porphyromonas gingivalis (Pg), Actinobacillus actinomycetemcomitans (Aa), Tannerella forsythia, Treponema denticola (Td), Prevotella intermedia (Pi), and Prevotella nigrescens (Pn). Genetic variations of the Pg fimA gene were also examined. Bacterial occurrence was compared with the severity of GO, and alterations in the bacterial occurrence rate and quantities were monitored following periodontal treatment.

RESULTS

The occurrences of Aa, Td, Pi, Pn, and Pg with type II fimA (type II Pg) were significantly associated with the severity of GO. Td occurrence was reduced in association with gingival improvement following ultrasonic scaling, however, no such relationship was observed with Aa, Pi, Pn, and Pg. In addition, Pg and Pi markedly persisted after treatment. Clinical improvement of the sites, following an Er:YAG laser treatment, significantly associated with quantitative reduction of Pg in improved sites, however, not that of Pi.

CONCLUSION

Type II Pg and Td were each found to have a significant relationship with the development and deterioration of GO.

220-fs erbium-ytterbium:glass laser mode locked by a broadband low-loss silicon/germanium saturable absorber

We demonstrate femtosecond performance of an ultrabroadband high-index-contrast saturable Bragg reflector consisting of a silicon/silicon dioxide/germanium structure that is fully compatible with CMOS processing. This device offers a reflectivity bandwidth of over 700 nm and subpicosecond recovery time of the saturable loss. It is used to achieve mode locking of an Er-Yb:glass laser centered at 1540 nm, generating 220-fs pulses, with what is to our knowledge the broadest output spectrum to date.

Methylation pattern of CDH13 gene in digestive tract cancers

Recently, the loss of CDH13 (T-cadherin, H-cadherin) gene expression accompanied by CDH13 promoter methylation was identified in colon cancers. We examined CDH13 methylation in oesophageal and gastric carcinomas. Five of 37 oesophageal cancers (14%) and 23 of 66 gastric cancers (35%) demonstrated abnormal methylation of the CDH13 promoter. Abnormal methylation was frequently found in gastric cancers of patients at all clinical stages just as in E-cadherin, another of the cadherin family, suggesting that these cancers could be methylated at an early stage. These results suggested that CDH13 might play a variety of roles depending on the tissue type.

CDH13 promoter region is specifically methylated in poorly differentiated colorectal cancer

It has recently become clear that CDH13 (H-cadherin, T-cadherin) expression is frequently silenced by aberrant methylation in colorectal cancers and adenomas. In this study, we investigated the methylation status of CDH13 gene and detected aberrant promoter methylation in 27 of 84 (32%) colorectal cancers. We then correlated the results with the clinicopathological features of affected patients. We found a significant difference in histology (P=0.0053) when we compared the CDH13 methylation of poorly differentiated colorectal cancers to that of differentiated ones. This result suggested that poorly differentiated colorectal cancers specifically exhibited CDH13 methylation, and since CDH13 might be responsible for selective cell recognition and adhesion, inactivation of CDH13 could lead to the formation of scattered carcinoma cells in these cancers.

Adenovirus-mediated transduction of Escherichia coli uracil phosphoribosyltransferase gene increases the sensitivity of esophageal cancer cells to 5-fluorouracil

Esophageal cancer is associated with the poorest prognosis among the digestive tract cancers, and chemotherapy is the treatment of choice for many patients. In this study, we experimentally introduced an Escherichia coli-derived uracil phosphoribosyltransferase (UPRT) gene to cultured esophageal cancer cell lines to potentiate the antitumor effects of a representative anticancer drug, 5-fluorouacil (5-FU). UPRT is a pyrimidine salvage enzyme that catalyzes the synthesis of uridine monophosphate from uracil and PRPP. The UPRT gene was transduced into five cultured esophageal cancer cell lines, TE1, TE2, TE3, NUEC1, and T.T, using an adenovirus vector. It was confirmed that the sensitivities of all cultured cell lines to 5-FU were increased in vitro. Subsequently, the T.T line was subcutaneously inoculated into nude mice to induce tumors, after which 5-FU was administered intraperitoneally. When a UPRT gene-recombinant adenovirus vector was directly injected into the tumors, tumor proliferation was markedly inhibited compared with that in the group treated with 5-FU alone, suggesting potentiation of 5-FU sensitivity by UPRT gene transduction in vivo. Therefore, we potentiated the effects of commercially available anticancer drugs by gene transduction. Our method may prove useful as a new form of cancer gene therapy in the future.

[Mechanisms of drug resistance and reversal of the resistance]

The mechanisms for the resistance to anticancer agents have been vigorously studied and many factors that are involved in the resistance were found. Among the members of ABC transporter superfamily, P-glycoprotein, MRP1-5 and BCRP are involved in the drug resistance. LRP, identified as the major vault protein, is also related to drug resistance.

Paired tumor marker of soluble E-selectin and its ligand sialyl Lewis A in colorectal cancer

BACKGROUND

Better diagnosis of metastatic disease has been pursued by oncologists: however, many of the tumor markers have been still controversial. Our purpose was to estimate the usefulness of soluble E-selectin and its ligand sialyl Lewis A for more accurate diagnosis as a combined tumor marker for metastases in colorectal cancer.

METHODS

E-selectin and sialyl Lewis A, collected from preoperative blood, were measured of its levels in 54 patients with colorectal cancer classified according to Dukes' stage. E-selectin was assayed by enzyme-linked immunosorbent assay, whereas sialyl Lewis A was quantified by enzyme immunoassay using immunoclone kit.

RESULTS

The elevation in the level of E-selectin was significantly higher in Dukes' D group than that of healthy volunteers (P < 0.001, Fisher's procedure of least significance test), Dukes' A (P = 0.01), B (P = 0.025) and C (P < 0.01). Significantly higher level of sialyl Lewis A was shown in the group of metastases than that of non-metastases (P < 0.0068. Student's t-test). Paired elevation of E-selectin and sialyl Lewis A was significantly higher in the hematogenous metastases than non-metastases (P < 0.001, Fisher exact test).

CONCLUSIONS

These results suggest that E-selectin could play some role in the progress of hematogenous metastases. The elevation of E-selectin alone or both E-selectin and sialyl Lewis A may be one of the useful indexes for more precise diagnosis of hematogenous metastases of human colorectal cancer.

Role of thymidine phosphorylase in Fas-induced apoptosis

Thymidine phosphorylase (TP) has chemotactic and angiogenic activity in vitro, and it promotes tumor growth and inhibits apoptosis in vivo. It plays a key role in the invasiveness and metastasis of TP-expressing solid tumors. KB/TP cells transfected with a TP cDNA have been shown to be resistant to hypoxia-induced apoptosis, suggesting that TP has effects on tumor growth and cell death independent of its effects on angiogenesis. However, the mechanisms of cell death inhibition by TP are unknown. In the present study, we demonstrate that caspase-8 is cleaved in control transfectant KB cells early on during Fas-induced apoptosis. Caspase-8 activation leads to the loss of mitochondrial membrane potential, followed by the release of cytochrome c, the activation of caspase-3, and apoptosis. In contrast, Fas-induced caspase-8 cleavage is inhibited in KB/TP cells, which lead to inhibition of the downstream apoptotic cascade and inhibition of apoptosis. These findings indicate that TP plays an important role in intracellular apoptotic signal transduction in the Fas-induced apoptotic pathway. Therefore, inhibition of TP may suppress the progression of TP-overexpressing solid tumors by inducing apoptosis.

Colorimetric fluoride ion sensing by boron-containing pi-electron systems

The boron-containing pi-conjugated systems, including tri(9-anthryl)borane (1) and tris[(10-dimesitylboryl)-9-anthryl]borane (2), have been investigated as a new type of fluoride chemosensor. Upon complexation of 1 with a fluoride ion, a significant color change from orange to colorless was observed and, in the UV-visible absorption spectra, the characteristic band of 1 at 470 nm disappeared and new bands around 360-400 nm assignable to pi-pi transitions of the anthryl moieties were observed. This change can be rationalized as a result of the interruption of the pi-conjugation extended through the vacant p-orbital of the boron atom by the formation of the corresponding fluoroborate. The binding constant of compound 1 with the fluoride ion was quite high [(2.8 +/- 0.3) x 10(5) M(-1)], whereas 1 only showed small binding constants with AcO- and OH- of around 10(3) M(-1) and no sensitivity to other halide ions such as Cl-, Br-, and I-, thus demonstrating its selective sensing ability to the fluoride ion. In contrast to the monoboron system 1, compound 2 having four boron atoms showed multistage changes in the absorption spectra by the stepwise complexation with fluoride ions.

Detection of mitochondrial DNA alterations in primary tumors and corresponding serum of colorectal cancer patients

We previously examined colorectal cancer patients using mutation-specific mismatch ligation assay for genetic alterations in primary tumors and paired serum samples and proved that genetic alterations present in the tumors of cancer patients can be detected in the serum of those same patients. Recent evidence has proved that various cancers frequently have mutations in the D-loop region of mitochondrial DNA (mtDNA). Therefore, we thought that mutations in the mitochondrial genome might also become a genetic marker of colorectal cancer to detect tumor DNA in the serum of patients. We first sequenced the D-loop region of mtDNA in colorectal cancers. We then proceeded with a sensitive method, i.e., mismatch ligation assay to examine the possibility that mtDNA alterations can be found in the serum DNA. We analyzed the D-loop region of mtDNA in 77 primary colorectal cancers, 7 of which (9%) contained true somatic mutations in this region. We then examined whether mtDNA alterations can be found in the serum DNA using mismatch ligation assay. Of 7 alterations that were examined, 1 (14%) could be detected in the serum. This result suggested that the mtDNA alteration could also be used as a tumor marker to detect tumor DNA in the serum.

Pharmacokinetic study of human natural beta-interferon in patients with end-stage renal failure

AIMS

Although human natural beta-interferon (beta-IFN) is currently used in the treatment of a number diseases, there have been no published studies of the pharmacokinetics and pharmacodynamics of beta-IFN in patients with end-stage renal failure.

MATERIALS

Five maintenance hemodialysis patients with chronic hepatitis C (4 men and 1 woman) were enrolled in this study.

METHODS

For the pharmacokinetic study, blood samples were obtained from a forearm vein at intervals, before infusion and 0, 3, 5, 10, 20, 30, and 40 minutes after a 15-minute intravenous infusion of human natural beta-IFN (Feron, Toray Industries, Inc., Tokyo) at a dose of 600 MIU.

RESULTS

Intravenous beta-IFN was administrated safely to all five patients. The plasma half-life of beta-IFN was found to be 6.91 +/- 2.80 (mean +/- SD) minutes. The initial volume of distribution was found to be 0.49 +/- 0.02 l/kg.

CONCLUSION

A 15-minute intravenous infusion of human natural beta-IFN was safely administered to the hemodialysis patients. This pharmacokinetic study showed that it is not necessary to reduce the dosage in patients with end-stage renal failure.