Central acinic cell carcinoma of the mandible. Report of a case

Central acinic cell carcinoma is extremely rare; only six cases have been reported in the literature. An unusual case of central acinic cell carcinoma of the mandible in an 84-year-old Japanese woman is presented. This is thought to be the seventh case of central acinic cell carcinoma described in the English literature.

Double stapling method of anastomosis after esophagectomy with endoscopic stapler to prevent postoperative stricture

To prevent stricture of an anastomotic site after operation of esophageal cancer, a new surgical technique, the "double-stapling method," was designed and applied clinically to 29 patients. According to the surgical technique, an automatic suture device for endoscopy was inserted from the side of the lesser curvature of the stomach to the esophageal side after performing end-side anastomosis between the esophagus and the stomach tube using a conventional circular anastomotic device to perform anastomosis between the anterior wall of the esophagus and the posterior wall of the stomach tube. As a result, a conventional anastomotic site, which was a plane (two dimensional), was transformed into a three-dimensional configuration. In the postoperative measurement of the anastomotic site using a measurement forceps, the inner diameter of the site was 8.6+/-3.1 mm in the circular group, while it was 17.2+/-4.5 mm in the DS group, showing a significant difference (p < 0.0001). Minor leakage was observed in three patients as a postoperative complication, but no postoperative hemorrhage occurred.

A new technique of hepatic vein reconstruction in living related liver transplantation

OBJECTIVE

To attempt to reconstruct the hepatic vein safely and easily in living related liver transplantation (LRLT).

DESIGN

Retrospective case series.

SUBJECTS

Four patients over 15 years of age underwent LRLT.

INTERVENTION

A surgical technique of hepatic vein anastomosis, using the common anastomotic orifice of the middle and left hepatic veins of a left lobe graft and the right hepatic vein of the recipient. After reperfusion, the graft is immobilized in a position decided upon using color Doppler ultrasonography to ensure no out-flow block.

RESULTS

The graft is lowered below the right diaphragm and rotated 90 degrees. This condition provides good visibility, enabling an accurate anastomosis. Four patients developed no complications included with out-flow block and hemorrhage.

CONCLUSIONS

This technique is safe and easy for reconstruction of the hepatic vein in LRLT.

Age-related changes in blood coagulation and fibrinolysis in mice fed on a high-cholesterol diet

To investigate the pathogenesis of hyperlipidemia-induced atherosclerosis, we examined age-dependent changes in platelet activity, blood coagulation and fibrinolysis in susceptibility to a high cholesterol diet (HCD) feeding in male ICR mice. Pretreatment of platelet-rich-plasma from HCD feeding mice for 3 days with epinephrine (300 microM) resulted in a marked enhancement of adenosine 5'-diphosphate (ADP: 0.1 microM) or collagen (0.7 microgram/ml)-stimulated aggregation compared with the same in control mice. Yohimbine as alpha 2-adrenergic blocker antagonized these aggregations in a dose-dependent manner. A significant increase in plasma total cholesterol and VLDL (very low-density lipoprotein)-LDL (low-density lipoprotein)-cholesterol and the liver/body weight ratio was observed in mice fed on HCD for 3 months (3-month HCD mice). In the early phase of this experiment, a significant increase in fibrinogen was observed. In the middle phase, increases in the activity of antithrombin III (ATIII) and alpha 2-plasmin inhibitor (alpha 2-Pl) followed. Plasminogen content gradually decreased in both normal diet and HCD mice throughout the experiment. The activity of plasminogen activator inhibitor (PAI) decreased in 3-month HCD mice. Morphological observation of the aortic arch from 3-month HCD mice revealed apparent atheromatous plaques not seen in control mice. These results suggest that 3-month HCD mice can be a convenient hyperlipidemia-induced atherosclerotic model and the changes in platelet activity, coagulation and fibrinolysis in the early phase may be a cause of pathologic changes in this model.

[Standardization of hemopoietic colony assay reagents]

Several Japanese Red Cross blood centers have begun cooperating with hospitals in peripheral blood stem cell transplantation research. However, most have not yet standardized their techniques or reagents for that purpose yet. Consequently, wide variations are often observed in data from different blood centers, especially for hemopoietic colony assays. We compared our colony assay reagent set with those in three commercial colony assay kits. The best results were obtained with the kit from a manufacturer referred to here as company A. Although our reagent set obtained lower colony values, the CFU-GM, BFU-E, and total colony values correlated well with those obtained using company A's kit (r = 0.74, 0.80, and 0.97, respectively). Company A's kit gave reproducible results even with the use of different lots, and includes reagents that can be stored for up to two years at -20 degrees C. These features highlighted its advantages as a standard reagent set.

Replication error frequencies in primary hepatocellular carcinoma: a comparison of solitary primary versus multiple primary cancers

AIMS/BACKGROUND

Replication errors (RERs) at microsatellite loci are associated with the development of not only hereditary nonpolyposis colon cancer but also sporadic cancers. To examine the association between RERs and human hepatocarcinogenesis, we looked for microsatellite instability in solitary and multiple primary hepatocellular carcinomas (HCCs).

METHODS

DNAs were extracted from 34 solitary primary HCCs and 14 HCCs with multiple primary cancers. Twelve microsatellite alleles were amplified by PCR from the DNAs, and RERs were assessed by their mobility shift.

RESULTS

RERs were found in only two cases (6%) of solitary HCC and four cases (29%) of HCC with multiple primary cancers. Two of the four HCCs with multiple primary cancers showed RERs at two and three microsatellite loci, respectively. Of 12 microsatellite loci examined, TP53 and D16S476 sensitively detected RERs in HCCs with multiple primary cancers, at a frequency of 23% and 33%, respectively.

CONCLUSIONS

RERs are rarely associated with carcinogenesis in human primary HCC, and RER-related genetic alterations may be associated with a part of HCC with multiple primary cancers. If future studies confirm this association, then the two probes TP53 and D16S476 may be useful for the prediction of development of multiple primary cancers with HCC.

Xeroderma pigmentosum group C protein complex is the initiator of global genome nucleotide excision repair

The XPC-HR23B complex is specifically involved in global genome but not transcription-coupled nucleotide excision repair (NER). Its function is unknown. Using a novel DNA damage recognition-competition assay, we identified XPC-HR23B as the earliest damage detector to initiate NER: it acts before the known damage-binding protein XPA. Coimmunoprecipitation and DNase I footprinting show that XPC-HR23B binds to a variety of NER lesions. These results resolve the function of XPC-HR23B, define the first NER stages, and suggest a two-step mechanism of damage recognition involving damage detection by XPC-HR23B followed by damage verification by XPA. This provides a plausible explanation for the extreme damage specificity exhibited by global genome repair. In analogy, in the transcription-coupled NER subpathway, RNA polymerase II may take the role of XPC. After this subpathway-specific initial lesion detection, XPA may function as a common damage verifier and adaptor to the core of the NER apparatus.

The (6-4) photoproduct of thymine-thymine induces targeted substitution mutations in mammalian cells

Two major ultraviolet-induced photolesions of TpT, a (6-4) photoproduct [T(6-4)T] and a cis-syn cyclobutane TT dimer (T=T), were incorporated into a predetermined site of one of the leading and lagging template strands of a double-stranded vector, and the modified DNAs were transfected into simian COS-7 cells. The DNAs replicated in the cells were recovered and were transfected again into Escherichia coli. The DNA replication efficiencies of plasmids containing T(6-4)T and T=T in the template strand for lagging strand synthesis were 93 and 79%, respectively, as compared with the unmodified DNA. Similar inhibitory effects were observed in the cases of the photoproducts in the template strand for leading strand synthesis (71 and 58%, respectively). These results indicated that T(6-4)T blocked DNA replication more weakly than T=T during leading and lagging strand syntheses in mammalian cells. The mutation frequencies of T(6-4)T were 2.3 and 4.7% in the leading and lagging template strands, respectively. The T=T lesion was less mutagenic and induced mutations with 0.2-0.7% frequencies. The T(6-4)T lesion primarily elicited 3'-T-->C substitutions, and T=T induced various types of mutations. These results indicate that T(6-4)T is more mutagenic than T=T during leading and lagging strand syntheses in simian cells. Moreover, this is the first evidence that shows T(6-4)T mainly elicits targeted substitutions at its 3'-T site in mammalian cells.

Detection, purification and characterization of a protein that binds the (6-4) photoproduct-containing DNA in HeLa cells

HeLa cell proteins that bind DNA containing the pyrimidine(6-4)pyrimidone photoproduct were detected by the electrophoretic mobility shift assay using synthetic oligonucleotide duplexes as probes. The major species was purified to near homogeneity, and the amino acid sequences of the proteolytic peptides revealed that it was the human damage-specific DNA-binding protein, which was reported previously. The substrate specificity of this protein was determined using damaged or modified DNA duplexes.

Improved technique for pancreaticogastrostomy with implantation method after pancreaticoduodenectomy

We performed improved pancreaticogastrostomy after pancreaticoduodenectomy in 60 consecutive patients between August, 1993 and July, 1997. Our improved pancreaticogastrostomy was made by implantation method with pancreatic duct stent. Two-layer fusion of anastomosis between full thickness or mucosa/submucosa of gastric wall and pancreatic parenchyma was completed via gastric lumen with gastrotomy in the anterior gastric wall. The morbidity and mortality rates were 3% and 0%, respectively. There was absolutely no pancreatic leakage, and no postoperative complications directly related to the pancreaticogastrostomy. The biggest advantage of this procedure was to be able to anastomose in a good field of vision via gastric lumen with gastrotomy in the anterior gastric wall. This improved pancreaticogastrostomy seemed to be technically very easy and a safe method.

[Two patients with obstructive jaundice due to intra-abdominal lymph-node metastases of gastric cancer responding to combination chemotherapy with 5-FU and CDDP]

Combination chemotherapy with 5-FU and CDDP was given to two patients with obstructive jaundice due to intra-abdominal lymph-node metastases of advanced and recurrent gastric cancer. One patient was a primary case associated with lymph-node metastases of portal fissure and periaorta, and the other was a recurrent case associated with lymph-node metastases of hepatoduodenal ligament and periaorta. The regimen consisted of 5-FU 1,000 mg/ m2 (day 1-5, continuous infusion) and CDDP 100 mg/m2 (day 3, 1 hr drip infusion). The interval was from the 6th to 21st day. The response to chemotherapy showed shrinking of intra-abdominal lymph-nodes and reopening of the biliary tract. The patients could be discharged from the hospital without PTBD tube and enjoyed a better quality of life (QOL). This therapy is thought to be effective against obstructive jaundice due to intra-abdominal lymph-node metastases of advanced and recurrent gastric cancer.

[Arterial infusion of SMANCS for multiple recurrent tumors after hepatic resection]

We investigated the possible side effects and efficacy of arterial infusion of SMANCS as compared to Lipiodol + epirubicin TAE for multiple recurrent tumors after hepatic resection. As a result, no significant difference in GOT, GPT, and total bilirubin was observed between the two groups. No significant difference was found in white blood cell count and platelet count, and there was no significant difference in clinical side effects between the two groups. Grade III response rates after arterial infusion of SMANCS were found in 4 patients (66.6%), and these results showed no significant difference as compared to Lipiodol + epirubicin TAE. Proper hepatic arterial infusion of SMANCS appeared to be useful in multiple recurrent tumors from the standpoints of safety and the rate of Lipiodol deposition.

Bimetallic system for nitrogen fixation: ruthenium-assisted protonation of coordinated N2 on tungsten with H2

Treatment of the tungsten dinitrogen complex cis-[W(N2)2(PMe2Ph)4] (Me = methyl, Ph = phenyl) with an equilibrium mixture of [RuCl(dppp)2]X and trans-[RuCl(eta2-H2)(dppp)2]X [X = BF4, PF6, or OSO2CF3; dppp = 1,3-bis(diphenylphosphino)propane] under 1 atmosphere of dihydrogen at 55 degrees Celsius for 24 hours gave NH3 in moderate yield. The same reaction in the presence of acetone produced acetone azine in high yield. None of these reactions proceeded in the absence of dihydrogen.

Cloning and characterization of a gene (UVR3) required for photorepair of 6-4 photoproducts in Arabidopsis thaliana

UV radiation induces two major classes of pyrimidine dimers: the pyrimidine [6-4] pyrimidone photoproduct (6-4 product) and the cyclobutane pyrimidine dimer (CPD). Many organisms produce enzymes, termed photolyases, that specifically bind to these damage products and split them via a UV-A/blue light-dependent mechanism, thereby reversing the damage. These photolyases are specific for either CPDs or 6-4 products. A gene that expresses a protein with 6-4 photolyase activity in vitro was recently cloned from Drosophila melanogaster and Xenopus laevis. We report here the isolation of a homolog of this gene, cloned on the basis of sequence similarity, from the higher plant Arabidopsis thaliana. This cloned gene produces a protein with 6-4 photolyase activity when expressed in Escherichia coli. We also find that a previously described mutant of Arabidopsis (uvr3) that is defective in photoreactivation of 6-4 products carries a nonsense mutation in this 6-4 photolyase homolog. We have therefore termed this gene UVR3. Although homologs of this gene have previously been shown to produce a functional 6-4 photolyase when expressed in heterologous systems, this is the first demonstration of a requirement for this gene for photoreactivation of 6-4 products in vivo.

Binding and catalytic properties of Xenopus (6-4) photolyase

Xenopus (6-4) photolyase binds with high affinity to DNA bearing a (6-4) photoproduct and repairs it in a light-dependent reaction. To clarify its repair mechanism of (6-4) photolyase, we determined its binding and catalytic properties using synthetic DNA substrate which carries a photoproduct at a single location. The (6-4) photolyase binds to T[6-4]T in double-stranded DNA with high affinity (KD = 10(-9)) and to T[6-4]T in single-stranded DNA and T[Dewar]T in double- and single-stranded DNA although with slightly lower affinity (KD = approximately 2 x 10(-8)). Majority of the T[6-4]T-(6-4) photolyase complex dissociates very slowly (koff = 2.9 x 10(-5) s-1). Its absolute action spectrum without a second chromophore in the 350-600 nm region closely matches the absorption spectrum of the enzyme. The quantum yield (phi) of repair is approximately 0.11. The fully reduced form (E-FADH-) of (6-4) photolyase is catalytically active. Direct analysis of the photoreactivated product showed that (6-4) photolyase restores the original pyrimidines. These findings demonstrate that cis, syn-cyclobutane pyrimidine dimer photolyase and (6-4) photolyase are quite similar, but they are different with regard to the binding properties.

Oral vancomycin hydrochloride therapy for postoperative methicillin-cephem-resistant Staphylococcus aureus enteritis

The postoperative development of methicillin-cephem-resistant Staphylococcus aureus (MRSA) enteritis can be fatal unless it is detected at an early stage and treated with effective antibacterial agents. We report herein a Japanese multicenter collaborative clinical study on the efficacy and safety of oral vancomycin hydrochloride (VCM) in the treatment of MRSA enteritis. A total of 49 patients who had been diagnosed as having, or were strongly suspected of having, MRSA enteritis during the early postoperative period, were given oral VCM as four standard doses of 0.5 g per day. The VCM concentrations in the blood, urine, and feces were then measured. No side effects were observed and the clinical efficacy of oral VCM in the 31 evaluable patients was excellent. There was a 100% clinical response rate and a 95.8% bacterial elimination rate in the feces. The clinical complete response (CR) rate to oral VCM differed significantly between patients in whom MRSA was detected only in the feces (100%) and those in whom MRSA was isolated from an additional source (57%) (P < 0.01). Although VCM concentrations in the stools were extremely high, the levels in the blood and urine were very low. These results demonstrate that oral VCM should be the treatment of choice for postoperative MRSA enteritis due to its safety and efficacy.

[Isolation rate of Enterococcus spp. from surgical infections and their susceptibilities]

Enterococcus spp. isolated from surgical infections during the period from July 1982 to June 1995 were investigated in a multicenter study involving 19 hospitals in Japan, and the following results were obtained. 1. Though the isolation rate of Enterococcus faecalis and other Enterococcus spp. were not high from primary infections, and from postoperative infections the isolation rate of other Enterococcus spp. was also low, the isolation rate of E. faecalis was highest from postoperative infections after 1993. 2. Vancomycin (VCM) showed strongest activity against E. faecalis, and followed by those of ampicillin (ABPC), imipenem. levofloxacin (LVFX) and meropenem in this order. Against other Enterococcus spp., VCM showed strongest activity, and followed by those of ABPC and LVFX. There were no resistant strains against VCM.

Inhibition of HIV-1 replication by targeting the Rev protein

Human immunodeficiency virus type 1 (HIV-1) encodes two regulatory proteins, Tat and Rev. The Rev protein facilitates the transport of unspliced and singly-spliced RNA to the cytoplasm in infected host cells by binding to target RNA (Rev response element: RRE). A variety of approaches targeting Rev function, including gene therapy, have been developed that inhibit HIV-1 replication in cells cultured in vitro. This minireview summarizes the recent developments as well as our application of the Rev-binding element-based decoy approach using RNA-DNA chimera oligonucleotide modeling.

Reflection-wavelength control method for layer-by-layer controlled x-ray multilayer mirrors

A reflection-wavelength control method for a layer-by-layer controlled x-ray multilayer mirror without interface roughness is proposed. The reflection wavelength of the multiperiodic mirror is found to be simply determined by a combination ratio of periodic layers. Multiperiodic x-ray mirrors with reflectance wavelengths at 3.374 nm (C VI 1s-2p) and 3.950 nm (Ca XVIII 3d-5f) are successfully designed.

Solution structure of an RNA.2'-O-methylated RNA hybrid duplex containing an RNA.DNA hybrid segment at the center

The solution structure of an RNA.2'-O-methylated RNA hybrid duplex containing an RNA.DNA hybrid segment at its center, (ggagaugac).(GmUmCmATCTCmCm), where lowercase letters, capital letters, and capital letters with the subscript m are RNA, DNA, and 2'-O-methylated RNA residues, respectively, was determined by observing the NMR spectra and performing the full relaxation matrix refinement. The 2'-O-methylation gives several characteristic features to oligoribonucleotides. In addition, this hybrid duplex is cleaved at a specific position by Escherichia coli ribonuclease HI, and so the role of the tertiary structure during the substrate recognition by the enzyme is of interest. The NOE connectivities among the proton resonances revealed that the duplex was a right handed helix. The 2'-O-methylated RNA segments had a typical C3'-endo conformation, and the 2'-O-methyl groups were directed to the minor groove of this duplex, taking the torsion angles phi (C1'-C2'-02'-CH3) that were all gauche(+). The DNA residues in the central RNA.DNA hybrid duplex formed the C3'-endo conformation, except for the middle thymine residue. No remarkable structural discontinuities were observed around the junction sites at either the 5'- or 3'-end of the DNA. The overall structure was close to the typical A-form duplex.

Thermodynamic studies of the hybridization properties of photolesions in DNA

In order to gain insight into the mechanism of mutations induced by photolesions in DNA, the thermal melting curves of oligonucleotide duplexes containing the (6-4) photoproducts of TT and TC and the Dewar isomer were measured at varying concentrations, and the thermodynamic parameters were determined. The duplexes were designed to be used as models for template-primer systems. In the case of d(CAXYAGCACGAC) x d(GTCGTGCTN), in which XY = T(6-4)T, T(6-4)C, or T(Dewar)T and N = A, G, C, or T, the -deltaG degrees values were the largest when N = G, and the difference between N = G and N = C or T was 1.1, 0.8, and 0.5 kcal/mol at 25 degrees C for XY = T(6-4)T, T(6-4)C, and T(Dewar)T, respectively. These results provide evidence of base pair formation between the 3'-pyrimidone and the opposite guanine, which was proposed previously to explain the T --> C transition induced at the 3' side of the T(6-4)T photoproduct. This interaction was weakened by isomerization to the Dewar photoproduct, which would explain the lower mutation specificity. For d(CAXYAGCACGAC) x d(GTCGTGCTGN), no obvious differences were observed regarding the base opposite the 5'-pyrimidine of the photoproducts. In contrast to the tertiary structure, determined by NMR, of a duplex containing T(6-4)T in its center [Kim, J.-K., & Choi, B.-S. (1995) Eur. J. Biochem. 228, 849-854], base pair formation at the 5'-pyrimidine was not detected for any photoproduct used in this study, even when the base opposite the 3'-pyrimidone of T(6-4)T was changed to adenine.

[Bacteria isolated from surgical infections and their susceptibilities to antimicrobial agents. Special references to bacteria isolated between July 1995 and June 1996]

Isolated bacteria from infections in general surgery during the period from July 1994 to June 1995 were investigated in a multicenter study in Japan, and the following results were obtained. One hundred and sixty-four strains were isolated from primary infections, and 202 strains were isolated from postoperative infections. From primary infections, anaerobic Gram-positive bacteria were predominant, while from post operative infections, aerobic Gram-positive bacteria were predominant. Among aerobic Gram-positive bacteria, the isolation rate of Enterococcus faecalis was the highest, followed by that of Staphylococcus aureus from postoperative infections. Among anaerobic Gram-positive bacteria, the isolation rate of Peptostreptococcus spp. was the highest from both types of infections. Among anaerobic Gram-negative, Escherichia coli was the most predominantly isolated from primary infections, followed by Klebsiella pneumoniae and Pseudomonas aeruginosa in this order, and from postoperative infections, P. aeruginosa was the most predominantly isolated, followed by Enterobacter spp. and Klebsiella spp. Among anaerobic Gram-negative bacteria, the isolation rate of Bacteroides fragilis group was the highest from both types of infections. We noticed that MICs of cefazolin against three out of 23 strains of E. coli were higher than 100 micrograms/ml. Among anaerobic bacteria, there were many resistant strains against penicillins and cephems with MICs higher than 100 micrograms/ml, and the same trend was observed among other Bacteroides spp. and Prevotella spp.

Decoy approach using RNA-DNA chimera oligonucleotides to inhibit the regulatory function of human immunodeficiency virus type 1 Rev protein

Human immunodeficiency virus type 1 (HIV-1) encodes two regulatory proteins, Tat and Rev, that bind to target RNA sequences. These are the trans-activation responsive (TAR) RNA and the Rev-responsive element (RRE), respectively. The Rev protein shifts RNA synthesis to viral transcripts by binding to the RRE within the env gene. In the present study we prepared a RNA-DNA chimera consisting of 29 or 31 nucleotides to inhibit the Rev regulatory function by means of the decoy approach. The chimera oligonucleotides (anti-Rev oligonucleotides [AROs]) contained an RNA "bubble" structure (13 oligonucleotides; the Rev-binding element in RRE) that bound Rev with a high affinity in an in vitro assay. The controls were RNA-DNA chimera oligonucleotides (negative control oligonucleotides [NCOs]) similar to ARO, but without the bubble structure, that bound with considerably less affinity to Rev. When the inhibitory effects of these decoys on HIV-1 replication were examined, we found that AROs, but no NCOs, reduced more than 90% of the HIV-1 production generated by productively infected human T-cell lines. The production of primary HIV-1 isolates in healthy donor-derived peripheral blood mononuclear cells was also similarly inhibited by AROs. In addition, the induction of viral mRNAs and antigens in latently HIV-1-infected ACH-2 cells by tumor necrosis factor alpha was specifically inhibited by AROs, but not by NCOs. No apparent cytotoxicity was caused by either decoy. Thus, the use of a Rev-binding element-based decoy, the RNA-DNA chimera oligonucleotide, may represent a safer approach to gene therapy for reducing the virus load in HIV-1-infected individuals.

[Clinically isolated bacterii seen in complicated infections]

The spectrum of causative bacterial agents responsible for post-operative infections in the surgical field have dramatically changed with time. This could be due to recent technical progress in bacterial extraction or the result of more effective antibiotics used post-operatively. Nevertheless nosocomial infections including those caused by MRSA still demand our close attention. Commonly extracted bacterii include Staphylococcus spp., E. faecalis, E. coli, Klebsiella spp., E. cloacae, P. aeruginosa and Bacteroides spp., but with regards to pathogenicity, extraction frequency and drug resistance, agents requiring the highest note of caution may be MRSA, P. aeruginosa and Bacteroides spp. MRSA is still the bacterium which makes the most frequent appearance in the clinical field, and the only effective antibiotic to MRSA is vancomycin. In addition, P. aeruginosa is the most common bacterial agent seen in post-operative infections and also the agent to which many of the cephem drugs do not express a high degree of antibacterial effect. Furthermore, about half of the Bacteroides spp. are beta-lactamase-producing strains which deactive the effect of penicillin and cephem drugs within the infection site. A drug which proves effective against E. coli may nevertheless become somewhat ineffective against this agent when found in a mixed infection and if the drug lacks stability against beta-lactamase. Clinically, mixed infections including some or even all the above agents are known to occur, continuously drawing our close attention.