Shape-memory alloy loop snare for endoscopic photodynamic therapy of early gastric cancer

BACKGROUND AND STUDY AIMS

Photodynamic therapy (PDT) has proved effective in the treatment of gastric cancer, but there is room for improvement. To achieve the technical goal of carrying out endoscopic PDT, endoscopists need to determine the precise area for laser irradiation at adequate dosages. This report describes the use of a shapememory alloy (SMA) loop snare as a useful tool in endoscopic PDT.

PATIENTS AND METHODS

Eleven patients with biopsy-proved early gastric cancer were treated with endoscopic PDT after intravenous injection of Photofrin II (2 mg/kg b.w.). Five patients underwent PDT using the SMA loop snare, and six underwent PDT without the use of the device. Cancer lesions smaller than 2 cm in diameter were irradiated with an excimer-dye laser (4 mJ, 80 Hz, 630 nm) for 20 min.

RESULTS

All five patients (100%) treated with PDT using the SMA loop snare, and four of the six patients (67%) treated with PDT without use of the SMA loop snare, showed complete remission.

CONCLUSIONS

The SMA loop snare routinely forms a circle 2 cm in diameter, covering an area of 3.14 cm2, and makes it possible to mark and calculate the precise area of cancerous lesions for irradiation at appropriate dosages. The findings of this study suggest that the SMA loop snare is an effective tool for PDT in early gastric cancer.

Electrochemotherapy for colorectal cancer with commonly used chemotherapeutic agents in a mouse model

We examined here the usefulness of electrochemotherapy against colorectal cancer (CRC) using a mouse model. Electropermeabilization profoundly increased the sensitivity of murine CRC, Colon 26, and MC38 cells to bleomycin (BLM) but not to 5-fluorouracil (5-FU) or to cisplatin (CDDP) in vitro. In vivo experiments revealed that electrochemotherapy with 5-FU, CDDP, or BLM was much more effective against CRC compared with the treatment of the drug alone. Electrochemotherapy with BLM or CDDP exhibited profound antitumor effects on subcutaneously established CRC in mice, and complete tumor regression was observed in five and four of eight animals, respectively. Electrochemotherapy with 5-FU also had an impact on CRC development, and complete cure was observed in one of eight animals. Subsequent analyses revealed that electropermeabilization significantly increased intratumoral amounts of BLM and CDDP but not 5-FU. These results indicate that electrochemotherapy may be a promising treatment modality against CRC.

Retrovirus-mediated in vivo gene therapy using the herpes simplex virus thymidine kinase gene against carcinomatous peritonitis

BACKGROUND

Carcinomatous peritonitis is characterized by massive malignant ascites, while peritoneally disseminated carcinomatosis is characterized by a large number of metastatic solid tumors in the peritoneal cavity. Although both are fatal end-stage manifestations of malignancies derived from the digestive system, the former is usually more serious than the latter due to massive malignant ascites. Although the effectiveness of gene therapy against peritoneally disseminated carcinomatosis has been shown in animal experiments, its effectiveness against carcinomatous peritonitis remains to be examined.

METHODS

A carcinomatous peritonitis model was made by inoculating murine hepatocellular carcinoma cells, MH134, into the peritoneal cavity of syngeneic C3H/He mice, resulting in production of massive malignant ascites without development of intraperitoneal solid tumors. Model animals were injected intraperitoneally with retroviruses carrying the herpes simplex virus thymidine kinase (HSV-tk) gene followed by ganciclovir (GCV) treatment.

RESULTS

Retrovirus-mediated in vivo gene therapy with the HSV-tk/GCV system was shown to have a significant impact on survival of animals with carcinomatous peritonitis not only at an early stage, but also at an advanced stage. Furthermore, repeated injections of HSV-tk-carrying retroviruses significantly prolonged the survival of animals with carcinomatous peritonitis compared with a single injection protocol. When intraperitoneal administration of recombinant interleukin-2 (IL-2) was added to the HSV-tk/GCV system, levels of IL-1beta and IL-2 in malignant ascites were significantly increased, resulting in significantly reduced ascite volume and prolonged survival.

CONCLUSIONS

Our results indicate the feasibility of retrovirus-mediated in vivo gene therapy with the HSV-tk/GCV system plus IL-2 treatment against carcinomatous peritonitis.

Particle-mediated gene transfer into murine livers using a newly developed gene gun

Although particle-mediated gene transfer using gene gun technology has been applied for gene transfer into epidermis, applications of this technology to visceral tissues have not been well investigated. Although all helium gas-driven gene gun instruments have used macrocarriers to discharge DNA-coated microprojectiles so far, we used a newly developed gene gun instrument, in which a hammering bullet is used to discharge microprojectiles. With the gene gun, gold particles coated with lacZ expression plasmid were discharged to murine livers. LacZ expression was induced much more profoundly in the liver by particle-mediated gene transfer than by simple plasmid injection and electroporation-mediated gene transfer. LacZ expression was broadly and randomly distributed throughout the bombarded livers, indicating that particle-mediated gene transfer can induce transgene expression even at relatively distant areas from the surface of the bombarded tissue. Furthermore, although transgene expression was at its peak on day 2 after the bombardment, it was still detectable even on day 28. These results indicate that particle-mediated gene transfer with a newly developed gene gun may provide a new approach to gene therapy for human diseases.

NMR determination of the absolute configuration of an alpha-exo-methylene-gamma-lactone

Both the enantiomers of the axially chiral reagent, 2'-methoxy-1,1'-binaphthalene-2-carbohydroximoyl chloride (MBCC), were used to convert igalan, an alpha-exo-methylene-gamma-lactone, to yield 4,5-dihydroisoxazoles. The absolute configuration of igalan was determined to be (3aR,5R,6R,7aR)-6-ethenylhexahydro-6-methyl-3-methylen e-5-(1-methylethenyl)-2(3H)-benzofuranone (IUPAC name) on the basis of NOE correlations in these derivatives. The absolute configurations of other alpha-exo-methylene-gamma-lactones can be determined by the same method.

Plasma endotoxin and serum cytokine levels in patients with alcoholic hepatitis: relation to severity of liver disturbance

BACKGROUND

Endotoxin plays an important role in the initiation and aggravation of alcoholic liver disease. In this study, we evaluated plasma endotoxin levels and serum concentrations of cytokines and lipopolysaccharide binding protein (LBP) during the acute and recovery phase of patients with alcoholic hepatitis; we also explored the prognostic factors associated with a fatal outcome.

METHODS

Fourteen patients, consisting of eight patients with alcoholic hepatitis (AH), five cirrhotics with superimposed AH (LC+AH), and one patient with severe alcoholic hepatitis (SAH), were studied. Among these, two with LC+AH died of hepatic failure.

RESULTS

Plasma endotoxin levels in the acute phase were higher in patients with AH (184.4 +/- 159.4 pg/ml) and LC+AH (206.9 +/- 174.9 pg/ml) than in healthy subjects (10.4 +/- 5.5 pg/ml, p < 0.001). In particular, in one patient with SAH and one of two nonsurvivors, plasma endotoxin levels were markedly high relative to the other cases. In most survivors, plasma endotoxin levels decreased in the recovery phase, whereas they further increased at the terminal stage in one of two nonsurvivors. Serum interleukin (IL)-6 and IL-8 levels in the acute phase were significantly higher in patients with AH and LC+AH as compared with healthy subjects. These levels were especially high in nonsurvivors and in one patient with SAH. IL-10 increased in two nonsurvivors, one patient with SAH, and one with LC+AH. In the recovery phase, these cytokine levels in survivors tended to decrease, but in nonsurvivors, IL-6 remained high, and IL-8 and IL-10 further increased. Tumor necrosis factor-alpha levels were below the detection limit throughout the course in all patients. Serum lipopolysaccharide binding protein (LBP) generally was elevated in the acute phase and decreased in the recovery phase in all survivors, but in one of the nonsurvivors, LBP was elevated markedly at the terminal stage. In the acute phase, plasma endotoxin levels were correlated positively with white blood cell counts, neutrophil counts, and serum IL-8. IL-8 was correlated positively with neutrophil counts and negatively with serum cholinesterase, hepaplastin test, and serum albumin levels. IL-6 was correlated positively with white blood cell and neutrophil counts, C-reactive protein, and serum total bilirubin and negatively with hepaplastin test and serum total protein levels. Serum LBP was correlated positively with white blood cell and neutrophil counts.

CONCLUSIONS

Endotoxemia and related elevation of IL-8 may play an important role in the activation and migration of neutrophils in patients with alcoholic hepatitis. Marked elevation of inflammatory cytokines, IL-6 and IL-8, are related to severity and poor prognosis of alcoholic hepatitis. Serum LBP may serve as an index of inflammatory reaction in alcoholics.

Microscopic polyangiitis that presented liver dysfunction prior to noted renal manifestations

In microscopic polyangiitis (MPA), renal manifestations are very common as first symptoms. Here, we report a case of MPA which presented liver dysfunction prior to noted renal manifestations. A 58-year-old woman was hospitalized because of a fever for 8 weeks. A laboratory examination revealed marked elevation of alkaline phosphatase and gamma-glutamyl transpeptidase, while blood urea nitrogen and creatinine levels remained normal. Although apparent renal dysfunction developed in this case soon after hospitalization, physicians should be aware of the variety of clinical manifestations in MPA. Moreover, antineutrophil cytoplasmic autoantibodies were found to be helpful for diagnosing MPA.

Enhanced urinary excretion of cysteinyl leukotrienes in patients with acute alcohol intoxication

BACKGROUND & AIMS

Leukotrienes are proinflammatory mediators. Ethanol inhibits the catabolism of both cysteinyl leukotrienes (leukotriene E(4) [LTE(4)] and N-acetyl-LTE(4)) and leukotriene B(4) (LTB(4)) in hepatocytes. We examined the metabolic derangement of leukotriene inactivation by ethanol in humans in vivo.

METHODS

LTE(4), N-acetyl-LTE(4), LTB(4), and 20-hydroxy-LTB(4) were quantified in urine samples from 16 patients with acute alcohol intoxication (mean blood ethanol, 75 mmol/L). In 9 healthy volunteers, urinary LTE(4) was determined before and after ethanol consumption (mean blood ethanol, 14 mmol/L).

RESULTS

The excretion of LTE(4) during alcohol intoxication was 286 compared with 36 nmol/mol creatinine in healthy subjects (P < 0.01); the corresponding values for N-acetyl-LTE(4) were 101 and 11 nmol/mol creatinine, respectively (P < 0.001). This excretion of cysteinyl leukotrienes decreased when the blood ethanol concentration returned to normal. LTB(4) and 20-hydroxy-LTB(4) were detectable only in patients with excessive blood ethanol concentrations (mean, 95 mmol/L). In healthy volunteers, LTE(4) excretion increased 3-5 hours after ethanol consumption (mean peak concentration of 1.5 nmol/L compared with 0.5 nmol/L for basal values; P < 0.005).

CONCLUSIONS

Ethanol at high concentration induces increased leukotriene excretion into urine. These changes are consistent with inhibition of leukotriene catabolism and inactivation induced by ethanol, as well as with a higher leukotriene formation caused by ethanol-induced endotoxemia.

Electrochemotherapy can eradicate established colorectal carcinoma and leaves a systemic protective memory in mice

Mice bearing subcutaneously established colorectal carcinoma (CRC) were given intratumoral, intravenous or intraperitoneal injection of various doses of bleomycin (BLM), followed by the delivery of direct current, square wave electric pulses to the tumor. Approximately 50% of animals treated with electrochemotherapy with BLM had completely eradicated established CRC tumors. Importantly, it was shown that CRC-specific cytotoxic T lymphocytes were elicited in the spleens of cured animals, resulting in the protection of the rechallenge with CRC. These results indicate that electrochemotherapy with BLM is promising for the treatment of metastatic CRC as well as the original lesion.

Usefulness and safety of theophylline injection form (Theodrip) for the treatment of acute asthma

The effects of the speed of intravenous infusion on the pharmacokinetics of theophylline were studied in 9 healthy volunteers (Ex I). Subjects were intravenously administered either six 4.8 mg/kg theophylline (Theodrip, Nikken Chemicals Co., Ltd., Japan) or three matching placebo injections (4.8 ml/kg physiological saline) for 30 min (Step I) or for 15 min (Step II). In Steps I and II, Cmax was 10.8 +/- 1.1 and 10.8 +/- 0.8 micrograms/ml, respectively. These Cmaxs were concentrations yielding therapeutic effects in patients with acute asthma. Next, comparative pharmacokinetics between theophylline (Theodrip) and aminophylline were examined by a crossover method in 16 healthy volunteers (Ex II). The 90% confidence limits of the differences of mean values were within 80-120% and were 92.8-100.1% for Cmax, 99.7-105.3% for t1/2 and 100.2-104.4% for AUC. Thus, we concluded that the pharmacokinetics of the plasma theophylline after intravenous administration of Theodrip (theophylline at 4.8 mg/kg) were bioequivalent to those of aminophylline (6.0 mg/kg) for 30 min. In Ex I and II, no subjects had adverse effects and in Ex I no influence on ECG was seen. In addition, the convenience of Theodrip was compared with that of ampules of aminophylline among nurse volunteers (Ex III). The times required for set-up of Theodrip were significantly shorter than those of aminophylline ampules. On the other hand, the adverse reactions to aminophylline resulting from hypersensitivity reactions to its ethylenediamine component have been reported. Theodrip consists of 200 mg theophylline and 200 ml physiological saline in a plastic bag. Therefore, Theodrip, which does not contain ethylenediamine, is expected to have less adverse effects and be easier to handle than aminophylline.

[Effect of radiotherapy for inoperable remnant and recurrent gastric cancer--focusing of improvement in quality of life]

We investigated six cases of inoperable remnant and recurrent gastric cancer treated with radiotherapy with regard to quality of life (QOL). The radiation dose was from 22 to 70 Gy, with a mean dose of 46 +/- 18 Gy. Four cases could be evaluated. Two were PR and two were NC. No patients could ingest food before radiotherapy, but two became able to eat whole gruel, one half gruel and three water. The mean survival time was 5.5 months and prognosis was not improved. Subjective symptoms such as food passage disturbance were decreased by radiotherapy and QOL was improved. Radiotherapy for patients with inoperable gastric cancer seemed to be effective in improving QOL.

A new chlorinated red naphthoquinone from roots of Sesamum indicum

A new chlorinated red naphthoquinone pigment having antifungal activity, named chlorosesamone, was isolated from the roots of Sesamum indicum. Its structure was characterized as 2-chloro-5,8-dihydroxy-3-(3methyl-2-butenyl)- 1,4-na phthoquinone on the basis of spectral evidence.

Immunomodulation with FK506 around the time of intravenous re-administration of an adenoviral vector facilitates gene transfer into primed rat liver

Although adenoviruses are an attractive vehicle for gene transfer into tissues including various tumors, in vivo adenoviral administration elicits a neutralizing antibody response which eliminates or substantially reduces the efficacy of subsequent treatments. Transiently immunosuppressive strategies at the time of initial adenoviral exposure have shown to prevent the formation of neutralizing antibodies and permit the successful adenoviral readministration in animals. Initial treatment in humans may, however, correspond to adenoviral readministration into animals, because the exposure to wild-type adenoviruses is common in humans. In the present study, we infused Adex1CAlacZ adenoviruses carrying the lacZ gene into the tail vein of rats, and examined whether a transient treatment with the immunosuppressant FK506 around the time of i.v. readministration of adenoviruses could induce the re-expression of the lacZ gene in animals primed with adenoviruses. Although i.v. infusion of adenoviruses carrying the lacZ gene resulted in transiently high levels of transgene expression in rat liver, i.v. reinfusion of adenoviruses failed to induce detectable levels of transgene expression. Conversely, when animals were treated transiently with FK506 around the time of adenoviral reinfusion, development of neutralizing antibodies and antigen-specific T cell proliferation in response to adenoviral reinfusion were significantly suppressed, and re-expression of the transgene was achievable.

Effect of the photocatalytic activity of TiO(2) on plasmid DNA

We investigated the photodynamic DNA strand-breaking activity of TiO(2). A solution of super-coiled pBR 322 DNA was irradiated with 5 J/cm(2) of UVA in the presence of TiO(2) and the products were analyzed by using gel electrophoresis. The ratio of open-circular DNA to super-coiled circular DNA was calculated from the resulting peak areas as a DNA strand-breaking index (SBI). The SBI of anatase-structure TiO(2) (band gap=3.23 eV) was greater than that of rutile structure (band gap=3.06 eV), and the level of SBI correlated with the photocatalytic activity for degradation of 2-propanol. The inhibitory effects of active oxygen scavengers, including DMSO, glutathione and histidine, on the DNA strand-breaking activity were examined. All of the scavengers except ascorbic acid showed inhibitory effects, as did several polyhydric alcohols including mannitol, a well-known hydroxyl radical scavenger. These results suggest that the photodynamic DNA strand-breaking activity of TiO(2) is due to active oxygen species, especially hydroxyl radicals. Polyhydric alcohols showed an inverse correlation between the inhibitory effect on DNA strand-breaking activity and the octanol/water partition coefficient (logP).

A new class of biflavonoids: 2'-hydroxygenistein dimers from the roots of white lupin

Two novel isoflavonoid dimers presumably originating from 2'-hydroxygenistein, 5,7,4'-trihydroxycoumaranochroman-4-one-(3-->5"')-5",7",2"'4"'- tetrahydroxyisoflavone (1, lupinalbisone A) and 5,7,4'-trihydroxycoumaranochroman-4-one-(3-6")-5",7",2"',4"'-te trahydroxyisoflavone (2, lupinalbisone B) were isolated from the roots of Lupinus albus L., and their structures involving relative stereochemistry were elucidated by spectroscopic methods. Using horse radish peroxidase and 2'-hydroxygenistein (3) as the substrate revealed the formation of these dimers together with 5,7,4'-trihydroxycoumaronochromone (4, lupinalbin A). Dimerization of 3 caused a remarkable increase of antifungal activity.

Immunohistochemical localization of cathepsin D in colorectal tumors

PURPOSE

Although it has been suggested that cathepsin D, a lysosomal protease, is involved in tumor invasion and metastasis in human colorectal cancers, conflicting studies have also been reported recently. In addition, this issue has been only rarely studied in human colorectal tumors by use of immunohistochemical methods. The aim of the study presented here was to clarify not only the correlation between cathepsin D expression and tumor invasion or metastasis but also the correlation between the intracellular immunostaining pattern of cathepsin D and tumor invasion and metastasis in human colorectal tumors.

METHODS

Thirty-four primary colorectal adenocarcinomas and 24 adenomas were immunostained by use of an anticathepsin D antibody. Both the incidence and the immunostaining patterns of cathepsin D were investigated in all tissue samples.

RESULTS

Three different immunostaining patterns, i.e., supranuclear, basal, and diffuse, were observed in samples containing cathepsin D. Although the incidence of cathepsin D-positive carcinomas was not correlated with tumor progression, invasion, or metastasis, the immunostaining pattern was significantly correlated with lymphatic invasion.

CONCLUSIONS

The results of this study suggest that abnormal cathepsin D immunostaining patterns (basal or diffuse) can be used to predict a potential for lymphatic invasion in colorectal carcinoma.

Incidence of P53 and K-ras alterations in ovarian mucinous and serous tumors

Clarification of the pathogenic relationships existing among ovarian cystadenomas, tumors of low malignant potential (LMP) and various adenocarcinoma types, a series of 29 mucinous and 19 serous ovarian tumors including adenomas, LMP tumors and adenocarcinomas were examined. P53 protein was detected by the streptavidin-biotin method and point mutation of K-ras codon 12 was detected by polymerase chain reaction-restriction fragment length polymorphism analysis. P53 overexpression was observed more frequently in serous adenocarcinomas (5/8, 63%) than in mucinous adenocarcinomas (2/9, 22%) and was correlated with the malignant potential of serous tumors. Furthermore, the proportion of P53-positive cells was significantly higher in serous adenocarcinomas than in mucinous adenocarcinomas. P53 overexpression may therefore be closely related to the early events of carcinogenesis in serous tumors. Although mutation of the K-ras oncogene appears to be an important event in the early tumorigenesis of mucinous tumors, mutation of the K-ras oncogene in serous tumors may be dependent on morphology. Different complex pathways of oncogene and/or tumor suppressor gene abnormalities may be involved in the development of mucinous and serous adenocarcinomas.

Rhythmic expression of BMAL1 mRNA is altered in Clock mutant mice: differential regulation in the suprachiasmatic nucleus and peripheral tissues

BMAL1 is a putative clock gene which encodes a basic helix-loop-helix (bHLH)-PAS transcription factor. To examine whether the CLOCK protein is required for the circadian expression of BMAL1 mRNA, in situ hybridization and Northern blot analysis were performed in the suprachiasmatic nucleus (SCN) and peripheral tissues of homozygous Clock mutant mice. In the SCN of Clock mutants, BMAL1 mRNA did not oscillate significantly but apparently expressed with low levels, while in wild-type mice the mRNA was robustly oscillated in a circadian manner. The peak-trough amplitudes of BMAL1 mRNA levels were 6.5-, 8.6-, and 6.7-fold in liver, heart, and kidney of wild-type mice, respectively. In Clock mutants, the amplitudes were extremely damped to 1.2-, 2.1-, and 1.4-fold, respectively. Furthermore, expressions of BMAL1 mRNA in the peripheral of Clock mutant mice were close to the peak level in wild-type mice, whereas mPer2 mRNA levels were severely blunted at trough values. Daily expression of albumin site D-binding protein (DBP), a clock controlled output gene (CCG), was also abolished at trough values by the Clock mutation in all tissues examined. These observations suggest that the circadian expression of BMAL1 mRNA is affected by the CLOCK-induced transcriptional feedback loop in the SCN and peripheral tissues in a different way and that the regulation mechanism appeared to be different from those in mPer2 and DBP expressions in vivo.

Electrochemotherapy with bleomycin against colorectal carcinoma in a mouse model: evaluations of the dose and administration route of the drug and the electric field intensity

Effectiveness of electrochemotherapy against colorectal carcinoma (CRC) was evaluated in a mouse model. When mice with a subcutaneously established CRC tumor were administered intratumorally, intravenously or intraperitoneally with bleomycin (BLM) ranging from 1/50 to 1/2 of the 50% lethal dose, significant suppression of tumor development and even some cures were observed. When various electric field intensities ranging from 500 to 2,000 V/cm were applied for electrochemotherapy with BLM, all treatment protocols were similarly effective. Furthermore, when electrochemotherapy with the lowest dose of BLM and the lowest electric field intensity was repeated, complete cures of CRC were achieved in all animals.

Mixed endothelin receptor antagonist, SB209670, decreases portal pressure in biliary cirrhotic rats in vivo by reducing portal venous system resistance

BACKGROUND/AIMS

This study aimed to evaluate the hemodynamic effects of endothelin-1 or mixed endothelin receptor antagonist, SB209670 in cirrhotic rats, and to elucidate the role of endothelin in cirrhotic portal hypertension.

METHODS

Secondary biliary cirrhosis was induced by bile duct ligation. Hemodynamics were studied using the radioactive microsphere technique.

RESULTS

Plasma and hepatic endothelin levels in cirrhotic rats were significantly higher than those in normal rats (plasma, 9.0+/-1.3 vs. 2.6+/-0.5 pg/ml, p<0.001; liver, 74.8+/-13.3 vs. 12.6+/-2.5 pg/g wet tissue, p<0.001). Intraportal administration of endothelin-1 (3 nmol/kg) progressively raised portal pressure without an initial transient reduction, which was observed in systemic arterial pressure, in both cirrhotic and normal rats. SB209670 (5.4 micromol/kg) reduced portal pressure in cirrhotic rats (-19+/-5%, p<0.01) without modifying systemic arterial pressure and renal blood flow, but not in normal rats. This reduction was associated with reduced portal venous system resistance (vehicle, 2.5+/-0.2 vs. SB209670, 1.7+/-0.1 mmHg x min x 100 g bw/ml, p<0.01), but not with change in portal venous inflow and collateral blood flow.

CONCLUSIONS

Mixed endothelin antagonist, SB209670, decreased portal pressure by reducing portal venous system resistance without modifying systemic arterial pressure and renal blood flow in cirrhotic rats. This result, together with the findings that plasma and hepatic endothelin levels were elevated in cirrhotic rats and that exogenous endothelin-1 increased portal pressure, provides further support for a role of endothelin in portal hypertension and suggests a potential use of mixed endothelin antagonist in the pharmacological treatment of portal hypertension.

Expression of heregulin alpha, erbB2, and erbB3 and their influences on proliferation of gastric epithelial cells

BACKGROUND & AIMS

Heregulins (HRGs) regulate the proliferation and differentiation of various cell types. However, very little is known about their function in the gastrointestinal tract. The aim of this study was to investigate the role of HRGs on gastrointestinal cells.

METHODS

We examined the expression of erbB receptors and HRG-alpha in human gastric cancer cell lines, rat gastrointestinal epithelial cells, and human gastric fibroblasts by Western blot analysis or reverse-transcription polymerase chain reaction. Receptor phosphorylation and heterodimerization induced by HRG-alpha were detected by Western blot analysis. We also evaluated the in vitro effects of HRG-alpha on cell proliferation and restitution.

RESULTS

Cancer cell lines and rat epithelial cells expressed erbB2 and erbB3, but protein expression of erbB4 was not detected. HRG-alpha was detected only in gastric fibroblasts. HRG-alpha activated tyrosine phosphorylation of epidermal growth factor receptor (EGFR), erbB2, and erbB3 and induced not only erbB3/erbB2 but also erbB3/EGFR and erbB2/EGFR heterodimer formation in MKN-28 cancer cells. Simultaneous cultivation of MKN-28 cells with gastric fibroblasts resulted in tyrosine phosphorylation of erbB3 in MKN-28 cells. HRG-alpha also stimulated proliferation of MKN-28 cells and gastric epithelial cells.

CONCLUSIONS

The data suggest that HRG-alpha may affect epithelial cell proliferation through mesenchymal-epithelial interaction in the gastric mucosa.

Effect of temperature on the incubation period and leaf colonization in bacterial blight of anthurium

ABSTRACT Effect of temperature on leaf colonization in anthurium blight was studied using a bioluminescent strain of Xanthomonas campestris pv. dieffenbachiae. In a susceptible cultivar, colonization of leaf tissues (monitored by detection of bioluminescence) and symptom development (assessed visually) advanced rapidly at higher temperatures. For a susceptible cultivar, there was a linear relationship between degree-days and percent leaf area colonized by the pathogen, indicating that leaf colonization in a susceptible cultivar was a direct function of the cumulative effect of temperature. The degree-day intercept of the regression line represented the time from inoculation to detection of bioluminescence, and the slope indicated the increase of leaf colonization per degree-day. There also was a linear relationship between the logarithm of degree-days and the logarithm of percent leaf area showing visible symptoms in a susceptible cultivar. The degree-day intercept of this relationship represented the incubation period (about 500 degree-days). The degree-days required to detect bioluminescence was not considerably different between susceptible and resistant cultivars. However, the subsequent rates of leaf colonization were significantly lower for a resistant cultivar than for a susceptible cultivar in all temperature regimes. The results suggest that multiplication of the pathogen in the leaf tissues is optimized in the susceptible cultivar. In contrast, in the resistant cultivar, the defense mechanisms overshadow the temperature effect. The differential response to temperatures may be an additional indicator of cultivar susceptibility.

KDR/Flk-1 is a major regulator of vascular endothelial growth factor-induced tumor development and angiogenesis in murine hepatocellular carcinoma cells

Vascular endothelial growth factor (VEGF), which is one of the most potent angiogenic factors, has been shown to play a pivotal role in tumor angiogenesis, including hepatocellular carcinoma (HCC). The effects of VEGF are mediated mainly through two distinct receptors, flt-1 and KDR/Flk-1. It has been suggested that KDR/Flk-1 plays an important role in tumor development. However, the role of KDR/Flk-1 in HCC has not been examined. We previously reported that VEGF tightly regulated murine HCC development, based on the results of a study using a retroviral tetracycline-regulated (Retro-Tet) gene expression system. This system allows VEGF gene expression to be manipulated in vivo by providing tetracycline in the drinking water. In the present study, we combined the KDR/Flk-1-specific neutralizing monoclonal antibody (KDR/Flk-1mAb) and the Retro-Tet system to elucidate the role of KDR/Flk-1 in VEGF-induced tumor development and angiogenesis in a murine HCC experimental model. In a xenograft study, tumor augmentation induced by VEGF overexpression was almost abolished by means of KDR/Flk-1mAb treatment, with accompanying inhibition of angiogenesis, KDR/Flk-1 autophosphorylation, but not interference of flt-1 activation. This inhibitory effect was achieved even on established tumors and regardless of whether the tumor size was small or large. On the contrary, KDR/Flk-1mAb treatment significantly increased the apoptosis in the tumor. With orthotopic transplantation, KDR/Flk-1mAb also inhibited HCC development in the liver. These results suggest that KDR/Flk-1 is a major regulator of VEGF-mediated HCC development and angiogenesis not only at the initial stage, but also after the tumor has fully developed.

Cancer gene therapy with HSV-tk/GCV system depends on T-cell-mediated immune responses and causes apoptotic death of tumor cells in vivo

To examine the immunological mechanisms involved in cancer gene therapy using the herpes simplex virus thymidine kinase (HSV-tk) gene and ganciclovir (GCV), murine hepatocellular carcinoma (HCC) cells, BNL1ME A.7R.1, were transduced retrovirally with the HSV-tk gene. HSV-tk-transduced cells exhibited a more than 2,000-fold higher sensitivity to GCV compared with untransduced parental cells. When HSV-tk-transduced HCC cells were mixed with parental cells at a 50% ratio and implanted subcutaneously into immunocompetent syngeneic mice, complete inhibition of tumor formation was achieved by GCV treatment. Conversely, no significant inhibitory effects on tumor formation were observed in athymic nude mice. When established solid tumors in immunocompetent mice containing HSV-tk-transduced cells at an only 5% ratio were treated with GCV, marked infiltration by lymphocytes including CD4(+) and CD8(+) ones, and apoptotic death of tumor cells were induced, and significant reduction or even complete regression of tumors was achieved. Furthermore, such cured mice rejected rechallenge with parental HCC cells into the contraflank regions. Our results indicate that cancer gene therapy with the HSV-tk/GCV system can indeed induce efficient antitumor effects and protective immunity in immunocompetent mice but not in nude mice, indicating that T-cell-mediated immune responses may be a critical factor for achieving successful gene therapy against cancer using the HSV-tk/GCV system.

A novel mutation of the KAL1 gene in Kallmann syndrome

Kallmann syndrome is defined by the association of hypogonadotropic hypogonadism and anosmia, for which three modes of transmission have been described: X-linked, autosomal recessive and autosomal dominant. The KAL1 gene, responsible for the X-linked form of the disease, has been isolated and its intron-exon organization determined. We report sequence analysis using PCR-direct sequencing method of the entire coding region and splice site junctions of the KAL1 gene in three males with Kallmann syndrome. We found a novel mutation in one case and no mutation in the other two cases. The mutation consisted of a C to T substitution in exon 1 converting codon 66 (CAG) encoding glutamine into a termination codon (TAG)/(Q66X). As a consequence of this mutation, the function of the KAL1 protein consisting of 680 amino acids was severely truncated so as to be consistent with Kallmann syndrome. As only this patient had unilateral renal hypoplasia among the three cases, this would suggest the existence of KAL1 gene mutation in this abnormality.

[Anti-tumor effects of carmofur on human 5-FU resistant cells]

As a part of studies to clarify the efficacy mechanism of carmofur (HCFU), a 5-FU analog, the degree of cross-resistance to HCFU of cell lines of cultured human colon cancer DLD-1 and a stomach cancer NUGC-3, both of which had acquired resistance to 5-FU, was studied in vitro and in vivo. In vitro, both resistant cell lines showed no or little cross-resistance to HCFU under a short-term drug exposure, and very low cross-resistance to HCFU, as compared to resistance to 5-FU, under a long-term drug exposure. In therapeutic experiments using nude mice bearing parent or subcutaneously transplanted 5-FU-resistant DLD-1 cells, HCFU exerted almost the same growth-inhibitory effects on both tumors. These results suggest that HCFU itself may have its own anti-tumor mechanism, different from that of 5-FU.

[Identification of PKC isozymes and effect of knockdown of PKC alpha by antisense oligodeoxynucleotide on iNOS expression via interleukin-1 receptor in vascular smooth muscle cells]

Protein kinase C (PKC) family, is now classified into three groups; conventional (cPKC), novel (nPKC) and atypical (aPKC), and to date, 10 members of isozymes have been identified. We have suggested that PKC is essential to interleukin-1 (IL-1)-triggered expression of inducible NO synthase (iNOS), and that by pharmacological analysis, cPKC is not involved in iNOS induction in rat vascular smooth muscle cells (VSMC). In the present study, we identified some PKC isozymes and investigated the effect of PKC alpha knockdown by antisense oligodeoxynucleotide (AS-ODN) strategy on iNOS expression and nuclear translocation of NF-kappa B in RASMC. Western blot analysis revealed the presence of cPKC (alpha), nPKCs (delta and epsilon) and aPKCs (tau and lambda). Short-time (10-20 min) treatment with phorbol 12-myristate 13-acetate (PMA) induced translocation of PKC alpha from cytosolic to particulate fraction. PKC alpha was completely downregulated by treatment with 100 nM PMA for 24 hours. Treatment with AS-ODN against PKC alpha mRNA depleted PKC alpha specifically, and had no detectable effect on the other PKCs. The production of iNOS mRNA, but not nuclear translocation of NF-kappa B, stimulated by IL-1 beta was decreased by PKC alpha knockdown. These results suggest that there are 5 PKC isozymes in RASMC, and that PKC alpha is involved in iNOS expression triggered by IL-1 beta, supporting our previous pharmacological conclusion.

Comparison of gene therapy with the herpes simplex virus thymidine kinase gene and the bacterial cytosine deaminase gene for the treatment of hepatocellular carcinoma

BACKGROUND

Bystander effects induced by suicide gene/prodrug systems play an essential role in achieving successful antitumor effects. Although it has been shown in several in vitro studies that the bacterial cytosine deaminase (CD) gene/5-fluorocytosine (5-FC) system is superior to the herpes simplex virus thymidine kinase (HSV-TK) gene/ganciclovir (GCV) system, we examined here which suicide gene system was more promising in vivo for the treatment of hepatocellular carcinoma (HCC).

METHODS

BNL1ME A.7R.1 murine HCC cells were retrovirally transduced with the HSV-TK or CD gene, and bystander effects caused by the appropriate prodrug treatment were examined not only in vitro but also in vivo.

RESULTS

The CD/5-FC system was superior to the HSV-TK/GCV system in HCC cell elimination in vitro. The bystander effect of the HSV-TK/GCV was shown to be substantially dependent on cell-to-cell contact, whereas that of the CD/5-FC was not. However, antitumor effects on HCC and tumor immunity to parental HCC induced by the HSV-TK/GCV system were not inferior and even superior to those induced by the CD/5-FC system. Bystander effects induced by the suicide gene/prodrug systems in immunocompetent syngeneic mice were much more profound than those induced in vitro. However, significant bystander effects were not observed in athymic nude mice.

CONCLUSIONS

These results suggest that both HSV-TK/GCV and CD/5-FC systems are useful for the treatment of HCC. The results also suggest that T-cell-mediated immune responses elicited by the suicide gene/prodrug systems play a substantial role in antitumor effects in vivo.

Glycyrrhizin inhibits TNF-induced, but not Fas-mediated, apoptosis in the human hepatoblastoma line HepG2

To determine the transaminase-lowering action of glycyrrhizin (GL) immunologically, the effect of GL on tumor necrosis factor (TNF)-alpha- and Fas-mediated apoptosis was assessed using a human hepatoblastoma line, HepG2 cells. The HepG2 cells were resistant to TNF-alpha and anti-Fas antibody, but were rendered susceptible to TNF-alpha and anti-Fas antibody in the presence of actinomycin D (Act D), an inhibitor of RNA synthesis. The cytotoxicity induced by TNF-alpha/Act D or anti-Fas/Act D was accompanied by DNA fragmentation, indicating apoptotic death of HepG2 cells. GL partially prevented the apoptosis of HepG2 cells induced by TNF-alpha/Act D in a GL-dose dependent fashion. However, this protective effect of GL was not observed in the cytotoxicity of HepG2 caused by anti-Fas/Act D. Although the protection mechanism of GL, observed in a limited fashion against TNF-alpha-mediated apoptosis, is unclear, the present results provide an immunological explanation for the transaminase-lowering action of GL in the GL treatment of chronic liver diseases involving apoptotic hepatocyte death in their pathogenesis.

Protein kinase C lies on the signaling pathway for vascular endothelial growth factor-mediated tumor development and angiogenesis

The growth of any solid tumor depends on angiogenesis. Among the known angiogenic factors, vascular endothelial growth factor (VEGF) has been shown to play a pivotal role in tumor angiogenesis. However, to date, the signal transduction pathway initiated by VEGF is still not fully understood. It has been suggested that protein kinase C (PKC) plays an important role in the VEGF-induced signal transduction pathway in vitro, although the role of PKC in tumor angiogenesis in vivo still remains to be elucidated. By delivering the VEGF gene within the self-contained tetracycline-regulated retroviral vector (Retro-Tet) into hepatocellular carcinoma (HCC) cells, we manipulated VEGF expression by providing tetracycline in the drinking water to assess the tumor kinetics mediated exclusively by VEGF. In this study, we combined this Retro-tet system and LY333531, an inhibitor of the PKC-beta isoform, to elucidate the role of PKC-beta in tumor development and angiogenesis. Using a syngenic xenograft model, tumor augmentation induced by VEGF overexpression in HCC was markedly suppressed by oral administration of the PKC-beta inhibitor, with an accompanying reduction of neovascularization and p44/42 mitogen-activated protein kinase activation. This inhibitory effect was achieved even after the tumor was fully established. Immunohistochemical analysis revealed that apoptosis increased markedly in the tumor upon PKC-beta inhibitor treatment, whereas tumor cell proliferation itself did not change. Furthermore, with orthotopical transplantation, PKC-beta inhibition suppressed HCC tumor development in the liver. These results suggest that PKC-beta lies on the signal transduction pathway by which VEGF augments development and angiogenesis not only at the initial stage but also after the tumor is fully established.

Detection of anaphylactic reaction in the percutaneously sensitized mouse using the AW method

Anaphylactic reactions of mice sensitized percutaneously with 2,4-dinitrofluorobenzene (DNFB) were investigated by the AW method assay, which is a mouse anaphylactic model using the abdominal wall as the site for induction with either 2,4-dinitrophenyl (DNP)-human serum albumin or anti-mouse IgE antibody and then estimation of the response. DNP-specific and IgE-dependent anaphylactic reaction after contact sensitization with DNFB could be induced and detected by the abdominal wall (AW) method assay in both groups with and without previous ear challenge with DNFB. Thus, the anaphylactic reaction in the group of twice-contact with 0.5% DNFB was observed on the 9th day from the sensitization (5th day from the ear challenge), and the reaction in the group of a single contact with 0.5% DNFB was observed 10 d after sensitization. The DNP-specific anaphylactic reaction was observed earlier than the 10th day with higher doses of DNFB. As for the mice of the former twice-contact group, the first and second characteristic ear swelling responses appeared within 1-6 h and 2 d of the ear challenge, respectively, and small swelling was observed 7 d after the challenge. It is suggested that Th1 and Th2 cells are activated at the almost same time, in other words, the preparation for both cell-mediated and humoral immunity could be accomplished to function, in vivo by a single percutaneous sensitization with DNFB.

Bileaflet mechanical valve (St. Jude Medical valve) replacement in long-term dialysis patients

BACKGROUND

Few reports exist on the results of bileaflet mechanical valve (St. Jude Medical prosthesis; St. Jude Medical, Inc, St. Paul, MN) replacement in long-term dialysis patients.

METHODS AND RESULTS

We retrospectively reviewed 12 patients, ranging in age from 50 to 86, undergoing long-term renal dialysis who had also undergone mechanical valve replacement at our institution. Operative procedures included aortic valve replacement, aortic and mitral valve replacement, aortic valve replacement and mitral annuloplasty, mitral valve replacement, and modified Bentall's operation. There was 1 hospital death (8.3%). During the mean follow-up period of 37.1 months (range: 5-87 months), there were 2 noncardiac late deaths. Bleeding from the esophageal varix and from a duodenal ulcer occurred in 1 patient with end-stage liver cirrhosis. There were no other major cases of bleeding or cerebrovascular accidents. There were no valve-related complications. All the survivors demonstrated excellent clinical improvement under the NYHA functional classification.

CONCLUSIONS

Our study demonstrated good early and long-term results of mechanical valve replacement in patients undergoing long-term dialysis. These favorable results support the continued use of mechanical valves in dialysis patients.

Effects of PAF on histamine H1 receptor mRNA expression in rat trigeminal ganglia

The application of platelet-activating factor (PAF) to the nasal mucosa of humans has been shown to increase histamine-induced hyper-reactivity. To test the hypothesis that PAF acts by increasing the reactivity of sensory nerve endings in the nasal mucosa to histamine, we examined PAF-stimulated rat trigeminal nerve ganglion cells. We found that relatively low concentrations of PAF (10(-12)-10(-9) M) induced increased histamine H1 receptor mRNA expression. This increase appeared as early as 1 h after PAF stimulation, peaked at 4 h, and disappeared after 24 h. The PAF receptor antagonist WEB2086 inhibited the increased expression of histamine H1 receptor mRNA induced by PAF, suggesting that the effects of PAF are mediated by specific receptors. This PAF effect was abolished by actinomycin D, suggesting that PAF induces de novo transcription of histamine H1 and/or PAF receptor mRNA. PAF may be important in the hyper-responsiveness of nasal mucosa exposed to histamine.

In vivo gene transfer of a suicide gene under the transcriptional control of the carcinoembryonic antigen promoter results in bone marrow transduction but can avoid bone marrow suppression

We constructed the CEA419/CD retrovirus vector carrying the cytosine deaminase (CD) gene directed by the carcinoembryonic antigen (CEA) promoter. pCD2 retrovirus vector carrying the CD gene directed by the retrovirus long terminal repeat promoter was also used. When mice bearing intraperitoneally disseminated colorectal carcinomas (CRCs) were infused intraperitoneally with pCD2 or CEA419/CD retrovirus-producing cells, a CD fragment was detected in CRCs and bone marrow cells. It was shown that the CD gene was expressed both in CRCs and in the bone marrow of animals infused with pCD2 retrovirus-producing cells, while the CD gene was expressed solely in CRCs of animals infused with CEA419/CD retrovirus-producing cells. These results indicate that the use of a tumor-selective promoter may warrant the safety of in vivo gene therapy using suicide genes.

Electrochemotherapy against colorectal carcinoma: comparison of in vitro cytotoxicity of 5-fluorouracil, cisplatin and bleomycin

Effectiveness of electrochemotherapy against colorectal carcinoma (CRC) was investigated in vitro using murine CRC cell lines. Electropermeabilization did not increase the sensitivity of CRC cells to 5-fluorouracil or cisplatin. Conversely, electropermeabilization markedly increased the sensitivity of CRC cells to bleomycin (BLM), resulting in 1,000-fold higher susceptibility. Subsequent analyses revealed that electropermeabilization significantly increased intracellular BLM levels of CRC cells. These results suggest that electrochemotherapy with BLM is a promising modality for the treatment of CRC, and that electrochemotherapy can be translated from the treatment of superficial tumors to the treatment of internal tumors including CRC.

Nystatin effects on vacuolar function in Saccharomyces cerevisiae

The effects of nystatin, a polyene antibiotic, was studied in Saccharomyces cerevisiae by isolating and characterizing nystatin-sensitive mutants. We isolated a number of nystatin-sensitive mutants by ethylmethane sulfonate mutagenesis. One of these mutants, the nss1 mutant, was characterized in detail. The mutant was sensitive to stresses such as high temperature or high concentrations of monovalent and divalent cations. The nss1 mutants showed severe vacuolar protein sorting and vacuolar morphology defects. The nss1 mutant was demonstrated to have a mutational lesion in the known VPS16 gene, which is essential for vacuolar protein sorting in S. cerevisiae. All of the vacuolar deficient mutants (vps11, vps16, vps18, and vps33) were sensitive to nystatin. Nystatin was found to cause extensive enlargement of the vacuole in wild-type S. cerevisiae cells. These results are discussed with special reference to the vacuolar function of S. cerevisiae.

Methotrexate produces delayed emesis in dogs: a potential model of delayed emesis induced by chemotherapy

We investigated the emetic effects of cisplatin and methotrexate in dogs, the effects of ondansetron on cisplatin-induced vomiting, and the effects of ondansetron, dexamethasone and a combination of the two on the vomiting induced by methotrexate. Ondansetron was administered 30 min before cisplatin administration. Ondansetron, dexamethasone or a combination of the two was administered 8, 24 and 48 h after methotrexate administration. Cisplatin (3 mg/kg, i.v.) induced acute vomiting but failed to induce delayed vomiting. The acute vomiting was markedly inhibited by ondansetron (3 mg/kg, p.o.; 1 mg/kg, i.v.). Methotrexate (2.5 mg/kg, i.v.) caused delayed vomiting, which was partly inhibited by ondansetron (1 mg/kg, i.v.) or dexamethasone (2.5 mg/kg, i.v.). The combination of the two agents was more effective. These results suggest that methotrexate-induced emesis in dogs would be useful for studying delayed emesis.

Cytosine deaminase/5-fluorocytosine gene therapy can induce efficient anti-tumor effects and protective immunity in immunocompetent mice but not in athymic nude mice

Murine hepatocellular carcinoma cells were retrovirally transduced with the bacterial cytosine deaminase (CD) gene. CD-transduced cells exhibited more than 120-fold higher sensitivity to 5-fluorocytosine (5-FC) compared with parental cells. When syngeneic immunocompetent mice were inoculated s.c. with parental hepatocellular carcinoma cells containing as little as 5% CD-transduced cells, significant inhibition of tumor formation was induced by 5-FC treatment. Furthermore, established solid tumors in immunocompetent mice containing only 5% CD-transduced cells were infiltrated markedly with CD4- and CD8+ T lymphocytes and macrophages by 5-FC treatment, such that significant reduction or even complete regression of tumors was observed. These tumor-free mice resisted subsequent rechallenge with wild-type tumor. Conversely, when athymic nude mice were inoculated with a cell mixture containing CD-transduced cells and parental cells at a ratio of 40:60, all developed tumors despite 5-FC treatment. Our results indicate that gene therapy using the CD/5-FC system can induce efficient anti-tumor effects and protective immunity in immunocompetent mice but not in athymic immunodeficient mice, suggesting that the host's immunocompetence may be a critical factor for achieving successful gene therapy against cancer.

[Ligand recognition and activation mechanism of histamine H1 receptor]

Five amino acid residues of the human histamine H1 receptor that participate in histamine binding were identified using mutant H1 receptors by site-directed mutagenesis and 3D computer modeling of the receptor. The computer modeling provided two conformations of the receptor, non-active and active forms, and it was hypothesized that the binding of histamine to the receptor leads to the active state through the rewinding of the alpha-helix of TM-V. The binding sites of histamine were divided into two groups, one determined the ligand affinity and the other directly participated in the conformational change of the receptor, and the H1 antagonists bound only to the former. The mode of binding of histamine to the H1 receptor was different from those of catecholamine to the beta-receptor and of histamine to the H2 receptor.

Transient cyclophosphamide treatment before intraportal readministration of an adenoviral vector can induce re-expression of the original gene construct in rat liver

Although adenovirus is an attractive vehicle for transferring therapeutic genes in vivo, animal studies have indicated that the clinical usefulness of adenoviruses may be limited by their immunogenicity. Although immunosuppressive strategies around the time of initial exposure of adenoviruses have been shown to prevent the formation of neutralizing antibodies and permit the successful readministration of adenoviruses in animals, the practicality of the approaches remains questionable. Because the majority of prospective gene therapy patients have already been infected with wild-type adenoviruses, initial treatment with adenoviruses in humans may correspond to readministration of adenoviruses into animals. It is shown here that although intraportal infusion of adenoviruses carrying a reporter lacZ gene resulted in transient high levels of transgene expression in the rat liver, intraportal readministration of adenoviruses failed to induce detectable levels of transgene expression. Conversely, when animals were treated transiently with cyclophosphamide before the intraportal readministration of adenoviruses, development of neutralizing antibodies and antigen-specific T cell proliferation in response to adenoviral readministration was significantly suppressed and successful re-expression of the transgene was achievable. These results may have important implications for efficacy considerations when adenoviral vectors are employed in clinical settings.

Comparisons of single versus multiple bacterial species on biological control of anthurium blight

ABSTRACT Effects of single versus multiple biological control agents (BCAs) on suppression of bacterial blight of anthurium were studied using a bioluminescent strain (V108LRUH1) of Xanthomonas campestris pv. dieffenbachiae. When five BCAs (GUT3, GUT4, GUT5, GUT6, and GUT9) were coinoculated in various combinations with V108LRUH1 into filter-sterilized guttation fluids of anthurium plants, a mixture of all five strains or four strains without GUT9 was most inhibitory to V108LRUH1. None of the individual BCAs inhibited V108LRUH1 in the guttation fluid. When BCAs were sprayed at congruent with10(8) CFU/ml on the foliage of a susceptible cultivar 1 day prior to inoculation with V108LRUH1, GUT6 alone and any mixtures containing GUT6 were highly effective in suppressing wound invasion and subsequent leaf infection by V108LRUH1. When tested on several cultivars that differed in susceptibility to the disease, the mixture of five strains or four strains without GUT9 consistently suppressed leaf infection regardless of the cultivars. In some cultivars, BCAs completely suppressed both wound and hydathode invasion by V108LRUH1, resulting in no infection in many leaves. These results indicate that application of bacterial mixtures provides anthurium cultivars with bacterial communities suppressive to X. campestris pv. dieffenbachiae. The results also suggest that selecting an effective mixture of BCAs first and then removing ineffective strains may be a better general approach to finding the most effective BCAs than finding individual strains and combining them.

Identification of protein kinase C phosphorylation sites involved in phorbol ester-induced desensitization of the histamine H1 receptor

The histamine H1 receptor (H1R)-mediated signaling cascade is inhibited by phorbol ester-induced protein kinase C (PKC) activation. Cloning studies of the H1Rs have shown that several potential PKC phosphorylation sites are located in the third intracellular loop of H1R. To elucidate the molecular mechanism of PKC-mediated desensitization, we identified amino acid residues that are involved in the desensitization of the H1R. Two amino acid residues (Ser396, Ser398) were determined to be PKC phosphorylation sites by in vitro phosphorylation studies using a series of synthetic peptides. Treatment with phorbol ester decreased histamine-induced accumulation of inositol phosphates in Chinese hamster ovary cells expressing the H1R with a rightward shift in the EC50 value, which implies the uncoupling of the receptor from the G protein. Site-directed mutagenesis studies showed that substitution of alanine for Ser398 but not for Ser396 markedly attenuated the effect of phorbol ester, which suggests that the Ser398 residue was primarily involved in PKC-mediated desensitization.