Measurement of the total purine contents and free nucleosides, nucleotides, and purine bases composition in Japanese anchovies (Engraulis japonicus) using high-performance liquid chromatography with UV detection

Dietary purine restrictions are recommended for patients with hyperuricemia and gout. While measuring the purine contents of various foods in our laboratory using high-performance liquid chromatography (HPLC), we observed and reported changes in purine composition. In this study, we measured the total purine content and free purine of raw anchovies as well as after fermentation, using two methods by HPLC. Method 1 involved acid hydrolysis of all purines, such as nucleic acids and nucleotides, to form four corresponding purine bases. Method 2, which is a non-hydrolysis method, is used to measure the amount of free purines (nucleotide, nucleoside, purine base). As a result of method 1, after fermentation, adenine-related and hypoxanthine-related purines and the total purine levels decreased significantly. Regardless of being raw or fermented, each anchovy contained mainly hypoxanthine- and guanine-related purines. Among the hypoxanthine-related purines, the results of method 2 revealed that the raw anchovies contained a lot of inosine monophosphate (IMP), while after fermentation contained more inosine. In guanine-related and adenine-related purines, those nucleotides decreased by fermentation and nucleosides and bases increased. Measurements of free purines revealed that those reductions after fermentation observed in method 1 were derived from decreased nucleotides. These results indicate that purines are affected by the fermentation bacteria and period.

Lactobacillus gasseri PA-3 directly incorporates purine mononucleotides and utilizes them for growth

Lactococcus lactis has been reported unable to directly incorporate mononucleotides but instead requires their external dephosphorylation by nucleotidases to the corresponding nucleosides prior to their incorporation. Although Lactobacillus gasseri PA-3 (PA-3), a strain of lactic acid bacteria, has been found to incorporate purine mononucleotides such as adenosine 5'-monophosphate (AMP), it remains unclear whether these bacteria directly incorporate these mononucleotides or incorporate them after dephosphorylation to the corresponding nucleosides. This study evaluated whether PA-3 incorporated radioactively-labeled mononucleotides in the presence or absence of the 5'-nucleotidase inhibitor α,β-methylene ADP (APCP). PA-3 took up ¹⁴C-AMP in the presence of APCP, as well as incorporating ³²P-AMP. Furthermore, radioactivity was detected in the RNA/DNA of bacterial cells cultured in the presence of ³²P-AMP. Taken together, these findings indicated that PA-3 incorporated purine mononucleotides directly rather than after their dephosphorylation to purine nucleosides and that PA-3 utilizes these purine mononucleotides in the synthesis of RNA and DNA. Although additional studies are required to identify purine mononucleotide transporters in PA-3, this study is the first to show that some lactic acid bacteria directly incorporate purine mononucleotides and use them for growth.

Species-dependent patterns of incorporation of purine mononucleotides and nucleosides by lactic acid bacteria

Although most lactic acid bacteria do not directly incorporate purine nucleotides, the strain Lactobacillus gasseri PA-3 was found to incorporate purine mononucleotides. To determine whether the direct uptake of purine mononucleotides is dependent on the species or strain of lactic acid bacteria, incorporation of purine mononucleotides was assessed in L. gasseri, Lactcoccus lactis sbsp. lactis, Streptococcus thermophilus and other species of lactic acid bacteria. Each bacterial strain was incubated with ³²P-AMP or ¹⁴C-adenosine and the incorporation of each purine was evaluated by measuring their radioactivity. All investigated strains of L. gasseri incorporated ³²P-AMP, whereas strains of S. thermophilus and most strains of L. lactis did not. Incorporation of ³²P-AMP into strains of Pediococcus was dependent on the strain or species of that genus of bacteria. All investigated strains, except for one strain of L. gasseri, incorporated ¹⁴C-adenosine, with S. thermophilus, L. lactis and Pediococcus generally displaying greater incorporation of ¹⁴C-adenosine than L. gasseri. Although most lactic acid bacteria such as S. thermophiles and L. lactis do not incorporate purine mononucleotides, some species such as L. gasseri directly incorporate purine mononucleotides. These findings indicate that the preferential incorporation of purine mononucleotides or nucleosides by lactic acid bacteria is dependent on the species or strain.

A Single Amino Acid Substitution in the Intervening Region of 129K Protein of Cucumber Green Mottle Mosaic Virus Resulted in Attenuated Symptoms

Cucumber green mottle mosaic virus (CGMMV), a member of the genus Tobamovirus, is a major threat to economically important cucurbit crops worldwide. An attenuated strain (SH33b) derived from a severe strain (SH) of CGMMV caused a reduction in the viral RNA accumulation and the attenuation of symptoms, and it has been successfully used to protect muskmelon plants against severe strains in Japan. In this study, we compared GFP-induced silencing suppression by the 129K protein and the methyltransferase domain plus intervening region (MTIR) of the 129K protein between the SH and SH33b strains, respectively. As a result, silencing suppression activity (SSA) in the GFP-silenced plants was inhibited efficiently by the MTIR and 129K protein of SH strain, and it coincided with drastically reduced accumulation of GFP-specific small interfering RNAs (siRNAs) but not by that of SH33b strain. Furthermore, analyses of siRNA binding capability (SBC) by the MTIR of 129K protein and 129K protein using electrophoretic mobility shift assay revealed that SBC was found with the MTIR and 129K protein of SH but not with that of SH33b, suggesting that a single amino acid mutation (E to G) in the MTIR is responsible for impaired SSA and SBC of SH33b. These data suggest that a single amino acid substitution in the intervening region of 129K protein of CGMMV resulted in attenuated symptoms by affecting RNA silencing suppression.

The observed variation in the purine composition of food after soaking in sake lees

In this study, we investigated the alterations in the purine composition of swordfish prepared using a traditional Japanese processing method of soaking in sake lees. These alterations are the byproducts of the yeast fermentation of rice-koji and are renowned for enhancing the umami nature of food. Using a conventional assay method for hydrolyzing all of the purines into four bases and our developed method for simultaneously analyzing purines, we observed the alterations in four purine bases in the soaked sake lees and swordfish. The findings showed that the total purine content, and hypoxanthine-related and guanine-related purines in swordfish decreased after soaking in sake lees. We also analyzed the free purine composition and showed that the ratio of IMP in swordfish was decreased by soaking, while that of inosine in sake lees was increased by soaking swordfish in it.

Simultaneous quantification by HPLC of purines in umami soup stock and evaluation of their effects on extracellular and intracellular purine metabolism

Ribonucleotide flavor enhancers such as inosine monophosphate (IMP) and guanosine monophosphate (GMP) provide umami taste, similarly to glutamine. Japanese cuisine frequently uses soup stocks containing these nucleotides to enhance umami. We quantified 18 types of purines (nucleotides, nucleosides, and purine bases) in three soup stocks (chicken, consommé, and dried bonito soup). IMP was the most abundant purine in all umami soup stocks, followed by hypoxanthine, inosine, and GMP. The IMP content of dried bonito soup was the highest of the three soup stocks. We also evaluated the effects of these purines on extracellular and intracellular purine metabolism in HepG2 cells after adding each umami soup stock to the cells. An increase in inosine and hypoxanthine was evident 1 h and 4 h after soup stock addition, and a low amount of xanthine and guanosine was observed in the extracellular medium. The addition of chicken soup stock resulted in increased intracellular and extracellular levels of uric acid and guanosine. Purine metabolism may be affected by ingredients present in soups.

Evaluation of cellular purine transport and metabolism in the Caco-2 cell using comprehensive high-performance liquid chromatography method for analysis of purines

Using Caco-2 cells and our previously developed high-performance liquid chromatography method for quantification of purine bases, nucleosides, and nucleotides, we evaluated cellular purine transport and uptake. The analytes were separated using YMC-Triart C18 column with gradient elution. We used Caco-2 cells as intestinal model cells and monitored purine transport across a monolayer for 2 h. The degree of change of purine concentrations in the permeate was very slight; however, it was possible to simultaneously determine these parameters for all purines because of our method's high sensitivity. In the present study, the purine bases (adenine, guanine, hypoxanthine, and xanthine) showed a relatively high permeability as compared with the nucleosides (adenosine, guanosine, inosine, and xanthosine). Increased concentration of metabolites in the permeate was also observed following the addition of purines. In a cell uptake assay, both the cell culture medium (extracellular) and the cells extracted from Caco-2 with acetonitrile:water (7:3) (intracellular) were measured. The additional nucleoside did not increase significantly within the cells. On the other hand, we observed that nucleotide, such as ATP, increased in the cell in a time-dependent manner following the addition of nucleoside. The additional nucleosides were considered to be rather recycled via the salvage pathway than metabolized to purine bases and/or uric acid in the cell. Such differences might have affected the increase in the serum uric acid levels depending on purine form.

Urinary excretion of uric acid, allantoin, and 8-OH-Deoxyguanosine in uricase-knockout mice

Although uricase-knockout (Uox KO) mice are reported to develop uric acid (UA) nephropathy, those that mature without severe nephropathy could be useful for research into purine metabolism in humans. In this study, we measured the urinary excretion of creatinine, UA, allantoin, and 8-hydroxy-2'-deoxyguanosine (8-OHdG) collected from Uox KO mice housed in metabolic cages. UA and allantoin were determined using liquid chromatography-mass spectrometry and creatinine and 8-OHdG were measured with a commercial kit. Uox KO mice excreted significantly higher levels of UA than wild-type mice (C57BL/6), while the excretion of allantoin was significantly lower. Urinary allantoin was detected in Uox KO mice despite a lack of uricase, which is the same as in humans. In contrast to the elevated levels of UA, the daily excretion of 8-OHdG, an oxidative stress marker, was lower in Uox KO mice. UA is thought to act as an anti-oxidizing agent in humans; thus, these results show that Uox KO mice are potential animal models for research into human purine metabolism.

Evaluation of purine utilization by Lactobacillus gasseri strains with potential to decrease the absorption of food-derived purines in the human intestine

It is well accepted that frequent and heavy intake of purine-rich foods causes elevation of serum uric acid levels, which is a risk factor of hyperuricemia. Reducing intestinal absorption of dietary purines may attenuate the elevation of serum uric acid levels and exacerbation of hyperuricemia. This reduction may be achieved by the ingestion of lactic acid bacteria that take up purines in the intestine. In this study, we investigated the degree of uptake and utilization of purines of three lactobacilli strains. Among them, Lactobacillus gasseri PA-3 (PA-3) showed the greatest incorporation of ¹⁴C-adenine. PA-3 also incorporated ¹⁴C-adenosine and ¹⁴C-AMP. Additionally, using defined growth medium, PA-3 demonstrated greater proliferation in the presence of these purines than in their absence. Although further investigation is required, ingestion of PA-3 may lower serum uric acid levels by reducing intestinal absorption of purines in humans.

Determination and profiling of purines in foods by using HPLC and LC-MS

Purines in food are known to raise serum uric acid levels. We determined the purine content of sweet potato and beef by high-performance liquid chromatography and liquid chromatography-mass spectrometry. The purine content of the samples was 118-1,034 μmol/100 g. The total purine content was also divided into purine bases, nucleosides, nucleotides, and nucleic acids. Our results suggest that differences in total purine content and in the ratio of purine types between vegetables and beef cause a difference in elevation of serum uric acid levels.

Characterizing substrate properties of purine-related compounds with purine metabolism enzymes for enzymatic peak-shift HPLC method

We have extended peak-shift method for measuring purine bases to make it suitable for other purine-related compounds. We optimized the reactions of the purine metabolism enzymes 5'-nucleotidase (EC 3.1.3.5), purine nucleoside phosphorylase (PNP) (EC 2.4.2.1), xanthine oxidase (XO) (EC 1.17.3.2), urate hydroxylase (EC 1.7.3.3), adenosine deaminase (ADA) (EC 3.5.4.4), and guanine deaminase (EC 3.5.4.3) by determining their substrate specificity and reaction kinetics. These enzymes eliminate the five purine base peaks (adenine, guanine, hypoxanthine, xanthine, and uric acid) and four nucleosides (adenosine, guanosine, inosine, and xanthosine). The bases and nucleosides can be identified and accurately quantified by comparing the chromatograms before and after treatment with the enzymes. Elimination of the individual purine compound peaks was complete in a few minutes. However, when there were multiple substrates, such as for XO, and when the metabolites were purine compounds, such as for PNP and ADA, it took longer to eliminate the peaks. The optimum reaction conditions for the peak-shift assay methods were an assay mixture containing the substrate (10 μL, 0.1 mg/mL), the combined enzyme solution (10 μL each, optimum concentration), and 50 mM sodium phosphate (up to 120 μL, pH 7.4). The mixture was incubated for 60 minutes at 37°C. This method should be suitable for determining the purine content of a variety of samples, without interference from impurities.

Simultaneous determination of purine and pyrimidine metabolites in HPRT-deficient cell lines

Genetic mutations in the purine salvage enzyme, hypoxanthine-guanine phosphoribosyltransferase (HPRT), are known to cause Lesch-Nyhan syndrome and Kelley-Seegmiller syndrome. In patients, purine metabolism is different from that of normal persons. We have previously developed a method for simultaneously determining the concentration of purine and pyrimidine nucleosides and nucleotides. This system was applied to determine the concentrations of nucleosides and nucleotides in HPRT-deficient cell lines. The amount of inosine 5'-monophosphate (IMP) was different in Lesch-Nyhan syndrome, Kelley-Seegmiller syndrome, and control cell lines. The difference in the amount of IMP confirmed the mutation of the enzyme.

Replication-competent retrovirus vector-mediated prodrug activator gene therapy in experimental models of human malignant mesothelioma

Replication-competent retrovirus (RCR) vectors have been shown to achieve significantly enhanced tumor transduction efficiency and therapeutic efficacy in various cancer models. In the present study, we investigated RCR vector-mediated prodrug activator gene therapy for the treatment of malignant mesothelioma, a highly aggressive tumor with poor prognosis. RCR-GFP vector expressing the green fluorescent protein marker gene successfully infected and efficiently replicated in human malignant mesothelioma cell lines, as compared with non-malignant mesothelial cells in vitro. In mice with pre-established subcutaneous tumor xenografts, RCR-GFP vector showed robust spread throughout entire tumor masses after intratumoral administration. Next, RCR-cytosine deaminase (RCR-CD), expressing the yeast CD prodrug activator gene, showed efficient transmission of the prodrug activator gene associated with replicative spread of the virus, resulting in efficient killing of malignant mesothelioma cells in a prodrug 5-fluorocytosine (5FC)-dose dependent manner in vitro. After a single intratumoral injection of RCR-CD followed by intraperitoneal administration of 5FC, RCR vector-mediated prodrug activator gene therapy achieved significant inhibition of subcutaneous tumor growth, and significantly prolonged survival in the disseminated peritoneal model of malignant mesothelioma. These data indicate the potential utility of RCR vector-mediated prodrug activator gene therapy in the treatment of malignant mesothelioma.

Analysis of purine in purine-rich cauliflower

Purine is a general term for purine nucleotides, nucleosides, bases, and nucleic acid. The amount of purine nucleotides, nucleosides, and bases in purine-rich cauliflower was determined with the use of LC-MS and HPLC, and the ratio of these molecules were compared with in raw and in heated condition. Total purine content of raw and heated cauliflower was 42.6 and 43.2 mg/100 g, respectively. Nucleotide content was increased from 0.02 to 50.8 micromol/100 g, and nucleoside content was decreased from 12.4 to 7.7 micromol/100 g, by heating.

[The efficacy of perioperative administration of steroid and erythromycin in the surgery for lung cancer complicated with interstitial pneumonia]

OBJECTIVES

We evaluated the efficacy of perioperative administration of steroid and erythromycin in surgery for lung cancer complicated with interstitial pneumonia (IP) to prevent postoperative acute exacerbation.

PATIENTS AND METHODS

We operated on 21 lung cancer patients with IP for 10 years. The patients were given 400 mg of erythromycin over 1 week before surgery and re-administered on the 1st operative day. The patients were also given 125 mg of methylprednisolone intravenously just before operation and continued until the 2nd operative day.

RESULTS

Lobectomy was performed in 16, segmentectomy or partial resection in 2 each, and completion pneumonectomy in 1. Three patients developed acute exacerbation of IP, but it occurred after the re-operation due to postoperative complications in 2. We experienced no operative death within 30 days, however, 2 died during the hospital stay due to multiple organ failure and sepsis. Seven of 21 patients had postoperative complications; air leakage over 1 week in 4, arrhythmia in 3, and atelectasis, postoperative bleeding, and pneumonia in 1 each, the morbidity rate was 33%.

CONCLUSIONS

We conclude that the administration of steroid and erythromycin in surgery for lung cancer with IP was suspected the usefulness to prevent a postoperative acute exacerbation of IP.

Resistance induction in barley coleoptile cells by intracellular pH decline

Cytoplasmic acidification in suspension-cultured plant cells has been characterized as a common intracellular response of some kinds of plant cells to elicitors. Expression of various defense genes in these cells has been increased by the cytoplasmic acidification itself without treatment by elicitors. It is not evident, however, whether or not cells with acidified cytoplasm actually exhibit resistance to the pathogen because of the lack of an adequate infection system between cultured plant cells and some pathogens. Using barley coleoptiles rather than suspension-cultured cells, we demonstrated both detection of cellular pH decline and increased resistance to Blumeria graminis. The cytoplasmic pH of barley coleoptile cells floated on 1 mM citrate buffer (CB), pH 4.0, became 0.5 unit lower than that of cells floated on 1 mM CB, pH 8.0, within 30 min after treatment. The penetration efficiency of B. graminis into the coleoptile was decreased in a pH-dependent manner; that is, when the coleoptiles were floated on 1 mM CB, pH 8.0, the penetration efficiency of the fungi was about 80%. In contrast, when the coleoptiles were floated on acidic buffers, the penetration efficiency decreased in parallel the decline of pH and the penetration efficiency reached 0% when coleoptiles were floated on 1 mM CB, pH 4.0. Morphogenesis of appressoria on the coleoptiles floating on CB was not influenced. The lowered penetration efficiency at lower pH was partially cancelled when the barley coleoptiles were irradiated with UV for 5 min prior to B. graminis inoculation. These findings suggest that the decline in cytoplasmic pH in barley coleoptile cells increases resistance to the pathogenic fungus B. graminis.

An aberrant left subclavian artery aneurysm with right aortic arch: report of a case

The case of a 41-year-old man who developed an aneurysm in his aberrant left subclavian artery is described. The patient had a right aortic arch. After a successful aortosubclavian artery bypass, symptoms due to brain ischemia disappeared. This is a very rare disease that is sometimes associated with an aortic anomaly, therefore the optimal therapeutic procedure need to be carefully selected, including the operative indications and approach.

[Methicillin-resistant Staphylococcus aureus (MRSA) mediastinitis after cardiovascular operations]

We described three cases of poststernotomy mediastinitis caused by MRSA. The first case 74-year-old woman who had undergone emergent CABG was treated by continuous closed irrigation and consecutive omental transfer. She was suffered from multiple organ failure and died. The other two cases 50-year-old woman and 66-year-old man after double valves replacement and total aortic arch replacement were managed successfully with simultaneous combination of surgical debridement and placement of omental flap. It was seemed that early aggressive surgical procedures before deterioration of general conditions associated with improvement of mortality. Additionally, it was considered that to avoid residual dead space in presternum as well as in mediastinum was essential to decrease the morbidity and hospital stay, especially in case of MRSA infection.

[Surgical treatment of lung cancer with combined resection of the aorta or superior vena cava]

Until December 1997, 699 cases of lung cancer were resected in our institute. Four cases of invasion into the aorta and seven cases of invasion into the superior vena cava were also operated and each vessels were reconstructed. Two pneumonectomies and nine lobectomies were performed. Four cases of squamous cell carcinoma, three of adenocarcinoma, three of large cell carcinoma and one of adenosquamous carcinoma were found on pathological examination. Four cases of N0, four of N2 and two of N3 were also detected on pathological lymph node evaluation. One case was stage IV with metastasis of ipsilateral axillar lymph nodes and the others were stage IIIB. With respect to pathological curability, absolutely noncurative operation was performed in all cases involving the aorta and absolutely noncurative in four and relatively curative three in cases involving the superior vena cava. During resection and reconstruction of the aorta, three cases received temporary blood supplying bypass and one case was underwent temporary clamping. Two cases developed bilateral lower extremity paralysis. During resection and reconstruction of the superior vena cava, one case underwent intraluminal temporary blood supplying bypass, two received sideclamping and four were reconstructed with double artificial grafts for bilateral innominate veins. Two cases who underwent resection of the aorta died within one year and one is alive after nine months of operation. Five cases who underwent resection of the superior vena cava died due to cancer. One case of N0 and relatively curative is alive in free of recurrence after seven years and six months of operation and another case who had brain metastasis resected is alive after two years and two months of pulmonary operation. Careful selection should be made for resection of the aorta because the prognosis is usually poor. In the resection of the superior vena cava, good prognosis is expected in some cases (N0, relatively curative) and quality of life is expected to improve with the prevention of the superior vena cava syndrome. Aggressive resection should be considered for lung cancer invasion into the superior vena cava.

Partial deficiency of hypoxanthine-guanine phosphoribosyltransferase manifesting as acute renal damage

A 32-year-old man who had had frequent gouty arthritis over the past 17 years, was admitted for acute renal failure. Acute renal failure was improved rapidly after medication was resumed and the patient was sufficiently hydrated. The hypoxanthine-guanine phosphoribosyltransferase (HPRT) activity in the patient had been reduced to about 30% of the normal control. Therefore we considered that this patient suffered from a partial deficiency of HPRT. A point mutation of HPRT gene 68G (guanine) to T (thymine) was detected. This is a mutation that has not been previously reported. Familial analysis indicated that his mother and sister were heterozygotes.

[Surgical results of T3 lung cancer with combined resection]

Forty six patients with T3 lung cancer underwent pulmonary resection in our institutes. The actual survival rate of lung cancer patients with invasion in pericardium at five years is significantly higher than that in parietal pleura and chest wall (63.5% vs 13.2%, 11.1%). The survival rate of patients with large cell lung cancer is significantly lower than that with squamous cell lung cancer and small cell lung cancer (0.0% vs 39.9%, 16.7%). It is suggested that T3 large cell lung cancer patients might be contraindication of pulmonary resection. The five-year survival rate of patients with n0, n1, n2 disease are 35.5%, 66.7%, 6.7% respectively. There are significant differences in survival rate between patients with n0 + n1 and n2 disease.

Changes in expression of the antigen recognized by monoclonal antibody A7 in human pancreatic carcinoma cells following exposure to anticancer agents

Techniques which can increase the expression level of tumor-associated antigens may improve immunotargeting therapy. We studied the reactivity of MAb A7 toward an antigen expressed on the surface of the human pancreatic cancer cell line HPC-YS after treatment with various antitumoral agents. When we applied 1 microg/ml mitomycin C (MMC) or 0.1 microg/ml neocarzinostatin (NCS) for 1 h, A7 recognizing antigen expression was enhanced until 24 h after the treatments. At a dose that completely suppressed cell growth, increased antigen expression was maintained for 96 h. Therefore, this study suggests that the combined application of an anticancer drug and MAb A7 may be useful for immunotargeting chemotherapy.

Targeted chemotherapy in mice with peritoneally disseminated gastric cancer using monoclonal antibody-drug conjugate

The murine monoclonal antibody A7 (MAb A7) is reactive against most human gastric cancer cell lines. Using a nude mouse peritoneal dissemination model of human gastric cancer, we investigated targeted chemotherapy using a conjugate of neocarzinostatin (NCS) with MAb A7 (A7-NCS). After demonstrating cytotoxicity of the complex against the human gastric cancer cell line MKN45 in vitro, we intraperitoneally injected A7-NCS, NCS or saline into nude mice bearing peritoneally disseminated human gastric cancer. A7-NCS inhibited peritoneal dissemination significantly more effectively than NCS. MAb A7 may prove to be an effective carrier for antineoplastic drugs in patients with peritoneal dissemination of gastric cancer.

Specific Binding of the Syringolide Elicitors to a Soluble Protein Fraction from Soybean Leaves

Syringolides are glycolipid elicitors produced by Gram-negative bacteria expressing Pseudomonas syringae avirulence gene D. The syringolides mediate gene-for-gene complementarity, inducing the hypersensitive response only in soybean plants carrying the Rpg4 disease resistance gene. A site(s) for 125I-syringolide 1 was detected in the soluble protein fraction from soybean leaves, but no evidence for ligand-specific binding to the microsomal fraction was obtained. The Kd value for syringolide 1 binding with the soluble fraction was 8.7 nM, and binding was greatly reduced by prior protease treatment or heating. A native gel assay was also used to demonstrate ligand-specific binding of labeled syringolide 1 with a soluble protein(s). Competition studies with 125I-syringolide 1 and several structural derivatives demonstrated a direct correlation between binding affinity to the soluble fraction and elicitor activity. However, differential competition binding studies disclosed no differences in syringolide binding to soluble fractions from Rpg4/Rpg4 or rpg4/rpg4 soybean leaves. Thus, the observed binding site fulfills several criteria expected of an intracellular receptor for the syringolides, but it is most likely not encoded by the Rpg4 gene. Instead, the Rpg4 gene product may function subsequent to elicitor binding, possibly in intracellular signal transduction.

The structure and function of a soybean beta-glucan-elicitor-binding protein

beta-Glucan elicitor (GE), released from the cell wall of the phytopathogenic fungus Phytophthora megasperma by soybean glucanases, causes defense reactions in soybean. A GE-binding protein (GEBP) was purified from the membrane fraction of soybean root cells, and its cDNA was isolated. Expression of the cDNA clone in tobacco suspension cultured cells and in Escherichia coli conferred GE-binding activity to both. An antibody against the recombinant protein was found to inhibit the GE binding with the soybean cotyledon membrane fraction as well as the resulting accumulation of phytoalexin. Immunolocalization assays indicated that the GEBPs are located in the plasma membrane of root cells. These results suggest that the cDNA encodes a GE receptor and may mediate the signaling of the elicitor.

Enhancement of tumor radio-response by irinotecan in human lung tumor xenografts

We investigated the ability of 7-ethyl-10-[4-(1-piperidino)-1-piperidino] carbonyloxycamptothecin (CPT-11) to increase tumor radio-response in vivo using human lung tumor xenografts. The xenografts were treated with (1) CPT-11 (10 mg/kg) intraperitoneally on days 1, 5 and 9, (2) single dose radiation (10 Gy/leg) on day 1, or (3) a combination regimen of both treatments in which radiation was given 1 h after the first dose of CPT-11. DNA flow cytometry studies were performed to define the cell cycle changes following treatment for 1 to 12 h with 0, 0.5, 2.0 or 8.0 ng/ml SN-38, the major active metabolite of CPT-11. In both small cell lung cancer (MS-1) and small cell/large cell carcinoma (LX-1) xenografts, combination treatment resulted in significant tumor regression compared with the use of CPT-11 (P = 0.0005, 0.0053) or radiation treatment (P = 0.00221, 0.0035) alone. Neither severe body weight loss nor enhanced skin reaction was observed following the combined treatment. In flow cytometry studies, the proportion of cells in G2/M-phase, the most radio-sensitive phase, increased after 1 h exposure to the lowest dose of SN-38 (0.5 ng/ml). These findings suggest that CPT-11 is a potent radiosensitizing agent, and that its activity is related to the cell cycle. This is the first report to indicate that CPT-11 serves as a radiosensitizer in vivo.

An asymptomatic germline missense base substitution in the hypoxanthine phosphoribosyltransferase (HPRT) gene that reduces the amount of enzyme in humans

A 40-year-old normouricemic (5.5 mg/dl) male showed 46% hemolysate and 37% lymphoblast hypoxanthine phosphoribosyltransferase (HPRT) activities but was otherwise completely free of symptoms. His genomic DNA and cDNA had a missense base substitution (CAT-to-CGT in codon 60) leading to the amino-acid substitution His-to-Arg. Western blot analysis revealed that the amount of HPRT protein in lymphoblasts from this individual was 25%-50% of normal cells, suggesting that the decrease in the amount of enzyme protein was responsible for the partial deficiency. This provides the first clear evidence that a genomic missense mutation at the HPRT locus leads to a decrease in the amount of the enzyme protein but that otherwise it has no evident adverse effects in the hemizygote (asymptomatic mutation).

[A resected case of bronchogenic cyst of the left hemidiaphragm with elevated serum CA19-9]

A rare case of bronchogenic cyst of the left hemidiaphragm is reported. A 53-year-old woman referred to our institution for an abnormal shadow on chest roentgenogram. Chest X-ray showed a 6 x 6 cm mass in the left lower lung filed. The margin of the mass was clear and the surface was smooth. The lateral view showed a mass on the diaphragm with the extrapleural sign. Chest CT demonstrated the mass as a multi loculated cyst. Celiac angiography demonstrated the branch of the inferior diaphragmatic artery at the margin of the mass. Her serum CA19-9 level was 470 U/ml. The patient underwent surgical exploration. Operative findings showed the smooth surface mass was on the diaphragm covered with pleura. Resected tumor was large as 7.5 x 6.5 x 4.0 cm. The surface was smooth and white-yellowish, and the cut surface presented a multi loculated cyts. Histopathological examination showed a bronchogenic cyst. CA19-9 in the cyst fluid was elevated as 445,900 U/ml. The serum CA19-9 level returned to normal after the operation.

Salivary drug monitoring of irinotecan and its active metabolite in cancer patients

To assess the clinical usefulness of salivary monitoring of irinotecan (CPT-11) and its active metabolite (SN-38), we examined the clinical pharmacological profile of both drugs in 9 patients with thoracic malignancies who received 60 mg/m2 CPT-11 (21 courses). Plasma and unstimulated whole saliva were collected over a 24-h period, and concentrations of CPT-11 and SN-38 were measured by high-performance liquid chromatography. Both CPT-11 and SN-38 were detectable in saliva, and the concentration-time curves in plasma and saliva showed a very similar pattern. A good correlation was observed between the saliva concentration (C3) and the plasma concentration (Cp) for both CPT-11 and SN-38 (r = 0.732, P < 0.0001 and r = 0.611, P < 0.0001, respectively). The area under the concentration-time curve calculated for saliva (AUCs) correlated with that generated for plasma (AUCp) for both CPT-11 and SN-38 (r = 0.531, P = 0.012 and r = 0.611, P = 0.0025, respectively). These results suggest that it may be feasible to use saliva instead of plasma for pharmacokinetics/pharmacodynamics studies of CPT-11.

No alteration in DNA topoisomerase I gene related to CPT-11 resistance in human lung cancer

Mutations and reduced expression of DNA topoisomerase I (topo I) gene have been shown to be important in the acquisition of resistance to camptothecin and its analogues in vitro, but their significance has not been verified in vivo. We investigated possible topo I gene mutations and topo I mRNA expression levels in 127 samples obtained from 56 patients with lung tumors, including patients who had developed clinical resistance to topo I inhibitors. No mutations were detected in any of the samples examined and expression levels did not differ significantly between clinically resistant cases and others. However, the topo I mRNA expression level was significantly higher in small cell lung carcinomas than in non-small cell lung carcinomas (P < 0.05). These results suggest that topo I mRNA levels may affect CPT-11 sensitivity in human lung cancer. However, topo I gene mutations and reduced topo I mRNA expression may not be the main mechanism of clinically acquired resistance to camptothecin analogues in vivo.

Successful application of an omental pedicle flap in delayed repair of a perforated esophageal diverticulum: report of a case

Mediastinitis resulting from a perforated esophageal diverticulum is a potentially fatal complication and the surgical treatment of persistent esophagomediastinal fistula may be difficult. In this report, we describe the successful application of an omental pedicle flap in the delayed repair of a perforated esophageal diverticulum. A 53-year-old man presented with chest and back pain and a diagnosis of perforated esophageal diverticulum was subsequently confirmed. After receiving conservative treatment, he was referred to our department and underwent surgical repair 6 months following the onset of the perforation. Through a right thoracotomy, the mucosal layer of the esophagus around the diverticulum was sutured, and an omental pedicle flap was used to cover the suture line and obliterate the fistulous tract. His postoperative course was uneventful and the suture line healed well. The successful treatment of this patient reinforces our belief that wider application of the omental pedicle flap can be expected in the field of thoracic surgery.

Detection of p53 gene mutations in cytopathology and biopsy specimens from patients with lung cancer

In order to ascertain the feasibility of detecting p53 gene mutations in patients with lung cancer in a nonsurgical diagnostic setting before starting treatment, we screened for p53 gene mutations in tumor specimens obtained using diagnostic methods such as fiberoptic bronchoscopy, thoracentesis, and percutaneous needle aspiration. We examined 206 specimens from 66 patients diagnosed with primary lung cancer at Hiroshima University Hospital between October 1991 and July 1993 using the polymerase chain reaction/denaturing gradient gel electrophoresis technique. p53 gene mutations were found in 64 of 159 (40%) cytologically positive specimens, but in none of 47 cytologically negative specimens. The PCR-based assay did not increase the sensitivity of the cytopathologic examination in detecting malignant cells. The type and location of the p53 gene mutation was the same in cytologically positive specimens obtained by different methods, but from the same patient. Of the 66 patients, p53 gene mutations were found in 27 (41%) at the time of the first nonsurgical diagnostic examination: 7 of 12 (58%) with small cell carcinoma, 9 of 20 (45%) with squamous cell carcinoma, and 11 of 34 (32%) with adenocarcinoma of the lung. The incidence of p53 gene mutation for each histologic subtype was comparable to previously published data examining surgically and/or autopsy-obtained specimens. These results indicate that detection of p53 gene mutations in a nonsurgical, diagnostic setting is feasible. This technique will make it possible to assess the significance of p53 gene mutations in relation to survival and response to therapy before starting treatment, in future prospective studies.

Bioavailability of 50- and 75-mg oral etoposide in lung cancer patients

This study was designed to determine the bioavailability of etoposide capsules administered orally at doses of 50 and 75 mg. Patients with inoperable or relapsed lung cancer, who had an Eastern Cooperative Oncology Group (ECOG) performance status of 0-2 and adequate organ function, were eligible. A group of 17 patients were evaluable, all of whom were 75 years old or less, with an ECOG performance status of 0 or 1. The bioavailability of oral etoposide was determined by measuring the area under the etoposide plasma concentration versus time curve (AUC) on days 1, 10 and 21 during a once-daily regimen of oral administration for 21 consecutive days and comparing the value with the AUC achieved following intravenous administration 1 or 2 weeks after the last oral dose. The bioavailability of 50, 75 and 100 mg oral etoposide was determined in six, nine and two patients, respectively. The mean etoposide bioavailabilities (+/- SD) of the 50-mg and 75-mg doses were 47 +/- 11% and 59 +/- 18%, respectively, and of the 100-mg dose in two patients were 51% and 33%, respectively. There was no statistically significant difference in bioavailability between the 50-mg and 75-mg doses. The bioavailability of low-dose oral etoposide was the same as that reported in previous higher dose oral etoposide bioavailability studies and that shown on the package insert supplied by the manufacturer. Improved bioavailability of low-dose oral etoposide was therefore not observed in a population of Japanese patients.

[Reconstruction procedure for full-thickness chest wall defects]

Reconstruction of full-thickness chest wall defects after the total layer resection of the chest wall has been performed on 6 cases. Five of 6 cases had local recurrent of breast carcinoma, one case had a recurrent liposarcoma in the chest wall. The reconstruction procedure of skeletal chest wall used to double soft Marlex mesh. The soft tissue layer of the chest wall was reconstructed with myocutaneous flaps in five cases (four cases using latissimus dorsi, one case using rectus abdominis), with omental pedicle graft and free skin flap in one case. Minor wound complications occurred in 2 in the 6 cases, one case had myocutaneous flap using rectus abdominis, the other case using omental pedicle flap, but any postoperative complications including respiratory insufficiency was not seen with myocutaneous flap using latissimus dorsi. The latissimus dorsi myocutaneous flap was most suitable to cover the soft tissue layer of the chest. We confirmed that Marlex mesh and latissimus dorsi myocutaneous flap were able to reconstructed for large defects of full-thickness chest wall involving the sternum, there were best approach to reconstruction full-thickness chest wall defects after total layer chest wall resection.

[Ocular metastasis necessitating enucleation of an eyeball after surgery for primary lung cancer]

A 68-year-old man was referred because of an abnormal shadow in the right upper lung field on a chest X-ray film. After the diagnosis of adenocarcinoma of the lung, left upper lobectomy was done. Histologically, adenocarcinoma with foci of squamous cell carcinoma was seen. About 11 months after that operation, he suddenly noticed a decrease in visual acuity on the left side. The fundus of the eye was tested and metastatic choroidal cancer was suspected. To prevent rupture, the eyeball was enucleated. The choroidal tumor appeared to have components of squamous cell carcinoma from primary lung cancer. About 7 months after enucleation of his eyeball, the patient was disease-free with no decrease in his quality of life. As a result of a recent increase in the incidence of lung cancer, it is important to pay attention to ophthalmological tests in patients with primary lung cancer.

A structural model for the mechanisms of elicitor release from fungal cell walls by plant beta-1,3-endoglucanase

The release of elicitor-active carbohydrates from fungal cell walls by beta-1,3-endoglucanase contained in host tissues has been implicated as one of the earliest processes in the interaction between soybean (Glycine max) and the fungal pathogen Phytophthora megasperma f. sp. glycinea leading to host defense responses such as phytoalexin production. The present study was conducted to evaluate the primary structure of the glucanase-released elicitor (RE). Gel-filtration chromatography of carbohydrates released from mycelial walls by purified soybean beta-1,3-endoglucanase resolved them into the four fractions (elicitor-active RE-I, -II, and -III and elicitor-inactive RE-IV). Sugar composition analysis indicated that all of the fractions were composed almost entirely of glucose. 1H- and 13C-nuclear magnetic resonance analysis indicated the presence of both beta-1,3- and beta-1,6-linkages for the elicitor-active RE-I, -II, and -III fractions and only beta-1,3 linkage for the elicitor-inactive RE-IV fraction. Methylation analysis and degradation studies employing beta-1,3-endo- and beta-1,3-exoglucanase further suggested that the basic structure of elicitor-active RE consists of beta-1,6-linked glucan backbone chains of various lengths with frequent side branches composed of beta-1,3-linked one or two glucose moieties. From these structural analyses of RE, a structural model of how RE is originally present in fungal cell walls and released by host beta-1,3-endoglucanase is also proposed.

High-performance liquid chromatographic determination of irinotecan (CPT-11) and its active metabolite (SN-38) in human plasma

A simplified method for the simultaneous determination of irinotecan (CPT-11, I) and its active metabolite (SN-38, II) in human plasma by high-performance liquid chromatography (HPLC) with fluorescence detection has been developed. Following the addition of the internal standard (I.S.) camptothecin, the drugs were extracted from plasma using methanol. The average extraction efficiencies were 87% for I, 90% for II and 90% for the I.S. Chromatography was performed using a TSK gel ODS-80Ts column, monitored at 556 nm (excitation wavelength, 380 nm) and the mobile phase was acetonitrile-50 mM disodium hydrogen phosphate (28:72) containing 5 mM heptanesulphonate (pH 3.0). The linear quantitation ranges for I and II were 30-2000 and 1-30 ng/ml, respectively.

Phase I study and clinical pharmacological evaluation of daily oral etoposide combined with carboplatin in patients with lung cancer

Twenty-eight patients with inoperable or relapsed lung cancer were given a combination of oral etoposide, administered once a day at doses ranging from 40 to 60 mg/m2/day (d) for 21 consecutive days, and carboplatin, administered intravenously over 1 h at doses ranging from 300 to 400 mg/m2 on day 1 to determine the appropriate doses of this combination. In addition, pharmacokinetic and pharmacodynamic analyses were performed. All the patients had a performance status of 0 to 1. Serum etoposide and free platinum (Pt) concentrations were measured using high-performance liquid chromatography and atomic absorption, respectively. Myelosuppression, nausea and vomiting were the dose-limiting toxicities of this schedule. The maximum tolerated dose (MTD) was 50 mg/m2/d oral etoposide for 21 days and 400 mg/m2 i.v. carboplatin on day 1. For heavily pretreated patients, the MTD was 40 mg/m2/d oral etoposide for 21 days and 350 mg/m2 i.v. carboplatin on day 1. No cumulative increase in the area under the concentration-time curve (AUC) for oral etoposide over time was observed. There were significant correlations between the free Pt serum level (6, 8, 12, 24 h post-dose) and etoposide AUC level (days 1, 10 and 21) for graded hematological toxicity, and the percentage decreases and nadir counts of hemoglobin, leukocytes, neutrophils and platelets. Several pharmacodynamic models were developed to predict the hematological toxicity. In order to facilitate pharmacodynamic evaluations in future studies, a limited sampling model for oral etoposide was also developed and validated.

Biodistribution of murine and chimeric Fab fragments of the monoclonal antibody A7 in human pancreatic cancer

Much recent research has focused on the use of monoclonal antibodies (MAbs) in the immunodetection of solid tumors. Fab fragments of MAbs are more suitable for immunoscintigraphy than intact MAbs. Recently, human-mouse chimeric antibodies have been developed in an effort to reduce human antimouse antibody (HAMA) production by murine MAbs in humans. In this study, 125I-labeled murine and chimeric Fab fragments of the MAb A7 were injected i.v. into nude mice bearing a human pancreatic cancer (HPC-YS) xenograft. The radioactivity in tumors and in normal tissues was subsequently measured. The tumor tissue/blood ratio (T/B) of 125I-labeled murine and chimeric Fab fragments of MAb A7 increased with time in a similar manner and reached 9.68 +/- 2.54 and 10.49 +/- 1.50, respectively, 24 h after injection. Moreover, the T/Bs of 125I-labeled murine and chimeric Fab fragments of MAb A7 were greater than the T/B of intact MAb A7. When mice bearing tumors that did not react with MAb A7 were studied, 125I-labeled murine and chimeric Fab fragments did not localize specifically to the tumors. These results suggests that chimeric Fab fragments of MAb A7 are useful carriers of radionuclides for the immunodetection of human pancreatic cancer, with equivalent activity to murine Fab fragments and less theoretical potential to induce a HAMA response.

[Reoperation for lung cancer: indications and operation methods in cardiopulmonary function]

A second pulmonary resection after initial operation for lung cancer was performed 20 patients (10 with a second primary lung cancer, 8 with a metastatic lung cancer, 2 with lung abscess in pulmonary aspergillosis). All patients had radical lobectomy in first operation. Eight patients underwent completion pneumonectomy, one patient had another lobectomy, two patients underwent wedge resection after initial ipsilateral lobectomy. One patient underwent contralateral lobectomy seven patients had contralateral wedge resection after initial lobectomy. Any patient did not dead within 30 days after the reoperation, not hospital death and major complications. When a second pulmonary resection (especially, completion pneumonectomy) is required, its radicality and the need to preserve residual respiratory function and cardiac function (FEV1.0 more than 800 ml/body and %FVC more than 35%, total pulmonary vascular resistance at the unilateral pulmonary artery artery occlusion test less than 700 dyne.sec.cm-5/m2) must be considered in making the decision to operation. The five-year survival rate after reoperation for patients with lung cancer was 41.0% according to the Kaplan-Meier methods. Patients with a second primary lung cancer (the three-year survival rate, 83.5%) have appeared to do better than those with pulmonary metastasis from lung cancer (the five-year survival rate, 25.6%) These results suggest that reoperation for lung cancer can be done safety, patients undergoing reoperation have a reasonable prospect for long-term survival.

Antitumor effect of neocarzinostatin conjugated to human/mouse chimeric Fab fragments of the monoclonal antibody A7 on human pancreatic carcinoma

The anticancer agent neocarzinostatin (NCS) was bound covalently to human/mouse chimeric Fab fragments of the monoclonal antibody A7 to form the conjugate chA7Fab-NCS. The antitumor effect of chA7Fab-NCS was tested by measuring the inhibition of 3H-thymidine incorporation into human pancreatic carcinoma cells. The chA7Fab-NCS was approximately 2.3 times as effective as free NCS against human pancreatic carcinoma cells which reacted with the monoclonal antibody A7. The antitumor activity of chA7Fab-NCS was inhibited by excess chA7Fab. ChA7Fab-NCS had an antitumor effect equivalent to free NCS on human pancreatic carcinoma cells which did not react with the monoclonal antibody A7. ChA7Fab-NCS appears to be a potentially useful conjugate for immunotargeting chemotherapy against pancreatic carcinoma.

In vitro reactivity and in vivo biodistribution of the monoclonal antibody A7 using human gastric carcinoma cell lines

The monoclonal antibody (MAb) A7 has been used to treat patients with colorectal or pancreatic carcinoma with encouraging results. We therefore determined if MAb A7 would also react with gastric carcinoma cell lines. MAb A7 reacted with seven of eight gastric carcinoma cell lines tested. The intensity of the reaction, measured by flow cytometry, was equal to that of WiDr (colon) and HPC-YS (pancreas) cell lines. In nude mice bearing xenografts of the MAb A7-reactive gastric cancer line MKN45, the percentage injected dose of MAb A7 per g of tumour tissue on day 7 was 9.79; this value was 77% of that on day 1. The in vivo tumour-to-blood ratio of MAb A7 was 2.77 on day 7. Therefore, MAb A7 has long-term retention at binding sites as well as a high probability, high intensity and high specificity of reactivity against gastric cancer, which make it an ideal drug carrier for immunotargeted chemotherapy and immunodiagnosis.