Inhibition of aflatoxin B1-induced initiation of hepatocarcinogenesis in the rat by green tea

Several studies have demonstrated that green tea (GT) inhibits various chemically induced cancers in experimental animals. In the present study, effect of GT has been examined on the initiation of aflatoxin B1 (AFB1)-induced hepatocarcinogenesis in the rat. Young male Fischer rats were given AIN-76A diet with or without 0.5% instant GT powder in their drinking water for 2 or 4 weeks. Initiation was examined by hepatic AFB1-DNA binding in vivo, AFB1 metabolism in vitro and by the appearance of AFB1-induced glutathione S-transferase placental form (GST-P)-positive hepatocytes detected by immunohistochemical method. There was no influence of GT feeding on microsome-mediated AFB1 binding to exogenous DNA. However, GT feeding enhanced microsome-mediated formation of non-toxic hydroxylated metabolites of AFB1 by 2-3-fold. Hepatic nuclear AFB1-DNA binding in vivo was significantly inhibited by about 20-30% in animals pretreated with GT: AFB1-induced GST-P positive single hepatocytes were inhibited significantly by 60-70% in rats pretreated with GT. These results suggest that feeding of GT inhibits initiation of AFB1-induced hepatocarcinogenesis in the rat by modulation of AFB1 metabolism, thereby inhibiting AFB1-DNA binding and AFB1-induced GST-P-positive hepatocytes.

Association between receptor protein-tyrosine phosphatase RPTPalpha and the Grb2 adaptor. Dual Src homology (SH) 2/SH3 domain requirement and functional consequences

Receptor protein-tyrosine phosphatase RPTPalpha is found associated in vivo with the adaptor protein Grb2. Formation of this complex, which contains no detectable levels of Sos, is known to depend on a C-terminal phosphorylated tyrosine residue (Tyr798) in RPTPalpha and on the Src homology (SH) 2 domain in Grb2 (, ). We show here that association of Grb2 with RPTPalpha also involves a critical function for the C-terminal SH3 domain of Grb2. Furthermore, Grb2 SH3 binding peptides interfere with RPTPalpha-Grb2 association in vitro, and the RPTPalpha protein can dissociate the Grb2-Sos complex in vivo. These observations constitute a novel mode of Grb2 association and suggest a model in which association with a tyrosine-phosphorylated protein restricts the repertoire of SH3 binding proteins with which Grb2 can simultaneously interact. The function of the Tyr798 tyrosine phosphorylation/Grb2 binding site in RPTPalpha was studied further by expression of wild type or mutant RPTPalpha proteins in PC12 cells. In these cells, wild type RPTPalpha interferes with acidic fibroblast growth factor-induced neurite outgrowth; this effect requires both the catalytic activity and the Grb2 binding Tyr798 residue in RPTPalpha. In contrast, expression of catalytically active RPTPalpha containing a mutated tyrosine phosphorylation/Grb2 association site enhances neurite outgrowth. Our observations associate a functional effect with tyrosine phosphorylation of, and ensuing association of signaling proteins with, a receptor protein-tyrosine phosphatase and raise the possibility that RPTPalpha association may modulate Grb2 function and vice versa.

Postoperative symptoms 24 hours after ambulatory anaesthesia

PURPOSE

To test the hypothesis that the type of surgical procedure influences the incidence of postoperative symptoms. Also the effect of demographic and clinical risk variables: age, sex, ASA status, duration of anaesthesia on the postoperative symptoms were evaluated for each type of surgery.

METHODS

Demographic, medical, anaesthetic and surgical data on 1,017 patients were prospectively collected by a research assistant who telephoned each patient 24 hr after discharge to administer a questionnaire to determine postoperative symptoms. Postoperative symptoms included incisional pain, nausea/vomiting, drowsiness, dizziness, headache and fever. In addition, 270 patients were asked the % (0-100) of their return to daily living function at 24 hr.

RESULTS

Incisional pain (26.9%), headache (11.6%), and drowsiness (11.5%) were the most frequently reported symptoms. Dizziness was reported by 9.7% and nausea/vomiting by 7.1%. Approximately 50% of patients undergoing laparoscopy, orthopaedic and general surgery reported 24-hr postoperative incisional pain. The incidence of 24-hr postoperative nausea/vomiting was highest after general 17.4%, orthopaedic, 11.2%, and laparoscopic surgery, 9.4%. Drowsiness was highest after laparoscopy 36.1%, followed by general surgery, 21.4%. Dizziness was most frequent after laparoscopy, 24.1%, followed by general surgery, 16.1%. After laparoscopy, postoperative drowsiness or dizziness was related to anaesthesia duration. After general surgery, postoperative dizziness or drowsiness were related to age; the younger the patient, the more likely the symptoms.

CONCLUSIONS

Postoperative pain, nausea/vomiting, drowsiness, dizziness, and headache were the more frequent postoperative symptoms 24 hr after ambulatory surgery and they were influenced by the type of surgical procedure. In addition, the type of surgery and the 24-hr postoperative symptoms determined the degree of return to daily living function.

Role of intracardiac angiotensin II in cardiac dysfunction of rat during septic shock

OBJECTIVE

To observe changes in the content of myocardial angiotensin II and its role in cardiac dysfunction of rat during septic shock.

METHODS

Septic shock model was produced by cecal ligation and puncture (CLP) operation on rats. Experimental rats were given captopril 15 mg.kg-1/d per os for 3 days before CLP operation. Mean blood pressure and left ventricular pressure were recorded. Myocardial angiotensin converting enzyme (ACE) activities were determined by a fluorometric assay and myocardial angiotensin II content was measured by radioimmunoassay. Highly purified membrane of sarcoplasmic reticulum (SR) was prepared from rat hearts. Assays were made of ATP-dependent Ca2+ uptake by cardiac SR and (3H) ryanodine binding to SR.

RESULTS

Myocardial angiotensin II content increased by 51.5% (P < 0.01) at the 18th hour post CLP, meanwhile there was a decrease in left ventricular +/- dp/dtmax value and the impairment in Ca2+ uptake and (3H) ryanodine binding to cardiac SR. Preliminary administration of captopril reduced myocardial ACE activity and angiotensin II content, but increased left ventricular +/- dp/dtmax value. In comparison to shock group, the initial rate and the capacity of SR Ca2+ uptake were increased by 120% (P < 0.01) and 33.9% (P < 0.05), the Bmax value of (3H) ryanodine binding to SR was also elevated, while the Kd value remained unchanged.

CONCLUSIONS

The elevated intracardiac angiotensin II, resulting from the activation of myocardial ACE during sepsis, probably serves as one of the important mediators participating in the pathogenesis of heart failure: the effects of angiotensin II may be associated with the disturbance of Ca2+ transport function of cardiac SR.

A novel ribozyme target site located in the HIV-1 nef open reading frame

We have tested the sequence UUC CAG UCA GAC CU, at position 9016--9029 within the HIV-1(SF2) nef open reading frame, for accessibility to antisense and hammerhead ribozyme attack. The accessibility was first studied using a phosphorothioate-modified 14-nt DNA oligo (complementary to the nef9016--9029 site). A dose-dependent repression of HIV-1(SF2) growth was observed in human peripheral blood mononuclear cells after exogenous administration of the oligo to the cell culture medium. A hammerhead ribozyme with a 6+7-nt antisense specificity for the nef9016--9029 site (hhRz.nef9016--9029) was constructed and transfected into the human T-cell line HUT78. Again, a dose-dependent repression of virus growth was observed when different individual clones expressing hhRz.nef9016--9029 were infected with HIV-1(SF2). A complete abrogation of virus production was observed after infection with a low (0.5 TCID50) HIV-1 titer. Increasing doses (2.5 and 12.5 TCID50) of HIV-1 virus yielded a low production (10(3)-fold reduced) of virus particles in most cases; but a complete, or close to complete, abrogation was observed even in individual cultures infected with the highest dose. Presence of proviral pol and gag sequences in hhRz.nef9016--9029-expressing HUT78 clones was assayed, using PCR. Interestingly, since no pol and gag PCR products could be detected, the results strongly indicated that the hammerhead ribozyme was already acting on the infecting HIV RNA before its reverse transcription and integration as proviral DNA. In summary, the results obtained in this study support the nef9016--9029 site as a strong new candidate for ribozymal gene therapy against HIV-1 infection.

[Quantitative method for the determination of contents of gastrodin in zhennaonin capsules]

This paper reports the determination of gastrodin by means of HPLC method. The results show that this method is sensitive, accurate and specific. The recovery of gastrodin is 98.8% with RSD 2.5%.

Toward the construction of integrated physical and genetic maps of the mouse genome using interspersed repetitive sequence PCR (IRS-PCR) genomics

Using two recently developed techniques, IRS-PCR YAC walking and IRS-PCR genotyping, a framework-integrated physical and genetic map of the mouse genome was constructed. The map consists of 821 contigs, containing 7746 YAC clones originating from three different YAC libraries. Three hundred eighty of the contigs have been anchored to the genetic map. Approximately 16% of the physical length of the mouse genome is estimated to be represented.

Investigation on inhibition of biological effects of endothelin

The effects of a series of substances on the biological function of endothelin (ET) are reported. The substances used are: synthetic inhibitors of endothelium derived relaxing factors (EDRFs), inhibitor of big-endothelin converting enzyme phosphoramidon, antiserum of endothelin, antagonists of endothelin A receptor BQ123 and JKC301, and two Chinese anti-snake venom herb medicines Lobelia radicans Thumb and Taris polyphylla Smith var. chinensis (Franch) Hara. The results showed that inhibiting the production of nitric oxide (NO) could stimulate ET release from vascular endothelium, elevate plasma ET and increase blood pressure. These changes could be reversed by L-arginine (L-Arg), the substrate of nitric oxide synthase (NOS). The amount of ET released by arterial endothelium could be increased or inhibited by inhibiting or stimulating the synthesis of prostacyclin (PGI2). The plasma ET level and blood pressure in both SHR and WKY rats could be decreased by giving phosphoramidon (PhR). The above results indicate that the biological effects of ET could be antagonized by inhibiting the synthesis or release of ET, decreasing the level of plasma ET, blocking the binding of ET with its receptor and using some Chinese anti-snake venom herb medicines.

[Isolation and reassociation of acetogen and methanogen in a syntrophobic coculture degrading butyrate anaerobically]

Anaerobic coculture BF2 which degraded butyrate into acetate and produced methane was isolated from granular methanogenic sludge. The coculture is associated syntrophically the Syntrophomonas subsp. saponavida strain CF2 with Methanobacterium formicicum strain MF2 and appeared to degraded C4 approximately C18 fatty acids including isobutyrate. The optimal temperature and pH for growth was 37 degrees C and 7.7 respectively. The strain CF2 was obtained in pure culture with crotonate as substrate and produces acetate and butyrate. The doubling time of strain CF2 in crotonate media was about 20 hours. Strain CF2 is Gram negative, slightly curved 0.2 approximately 0.3 x 2.0 approximately 3.0 micron with round ends, motile by lateral flagellation at the concave side, non sporeforming. With a hydrogen scavenging organism, such as Methanospillum hungatei JF1, Methanobacterium formicicum 1535, Methanobrevibacterium bryantii 1125 and Desulfovibrio sp. B11, the strain CF2 paired up and the defined coculture degraded butyrate to acetate. When the strain CF2 associated with the original accompanist, Methanobacterium formicius strain MF2, the reassociated couculture degraded butyrate to acetate and produced methane again.

[Effect of ginger-processing on beta-sitosterol and total alkaloid contents in Rhizoma Pinelliae]

The contents of beta-sitosterol of five processed products of Rhizoma Pinelliae we were determined by TLC. The result showed that the lowest content of beta-sitosterol was found in Rhizoma Pinelliae boiled with ginger juice (0.0180%), and the highest in raw Phizoma Panelliae (0.0572%). The contents of total alkaloid of five processed products of Phizoma Pinelliae were also determined by gravimetry and spectrophotometry with acid dye. The result showed that the highest content of total alkaloid was obtained in Rhizoma Pinelliae boiled with ginger juice and alum, and the lowest in Rhizoma Pinelliae boiled with ginger juice.

[Chest radiograph in assessing the results of treatment with 6-month short-course chemotherapy of pulmonary tuberculosis]

Chest radiograph was evaluated in 287 cases of smear-positive pulmonary tuberculosis treated with 6-month short course chemotheapy. After 6-month chemotherapy was completed, the results of chest rediography were in a similar trend comparing to that of sputum examination in 94.0% cases. During 18 months follow-up in 107 (37.9%) of 282 cases, the remained shadows in chest radiography continued to resolve and in 14 (58%) of 24 cases, remained in chest radiograph were closed. It is concluded that sputum examination in assessing the results of 6 months short-course chemotherapy simple, reliable and cheaper than chest radiography.

[An epidemiological study on reproductive effects in female workers exposed to acrylonitrile]

Four hundred and seventy-seven female workers exposed to acrylonitrile and 527 controls were studied by retrospective cohort method. Results showed incidence rates of pernicious vomiting and anemia, preterm delivery, and birth defects in exposed women were obviously higher than those in controls, with statistical significance. Logistic regression analysis revealed exposure to acrylonitrile in pregnant workers caused increasing risk of preterm delivery and birth defects. In addition, illness, medicine taking and X-ray irradiation during pregnancy related to the increase of incidence of preterm delivery in exposed women.

A new cytotoxic dihydroxy sterol from the soft coral Alcyonium patagonicum

A new sterol, 24-methylenecholest-4-ene-3 beta,6 beta-diol [1] was isolated from the soft coral Alcyonium patagonicum collected from the South China Sea. Its structure was determined by spectral analysis. Compound 1 was cytotoxic against the P-388 cell line with an IC50 value of 1 microgram/ml.

Antibiotic C3368-A, a fungus-derived nucleoside transport inhibitor, potentiates the activity of antitumor drugs

Antibiotic C3368-A (CA) is produced by a fungus strain from a soil sample collected in Antarctica. CA markedly inhibited radiolabeled thymidine and uridine transport in mouse Ehrlich carcinoma cells, its 50% inhibitory concentration (IC50) being 4.6 and 7.7 microM, respectively. In clonogenic assay, CA displayed a synergistic effect with methotrexate (MTX), mitomycin C (MMC), 5-fluorouracil (5FU), and Adriamycin (ADR) against human oral epidermoid carcinoma KB cells. CA also markedly enhanced the inhibitory effect of 5FU and ADR on the proliferation of human hepatoma BEL-7402 cells as determined by the p-nitrophenyl-N-acetyl-beta-D-glucosaminide (NAG) enzyme-reaction assay. 5FU or ADR cytotoxicity was not augmented by CA in human fetal lung 2BS cells. In vivo, CA significantly potentiated the inhibitory effect of MMC against colon carcinoma 26 in mice. No significant augmentation of toxicity by the combination was found in treated mice. The results suggest that CA, the newly found nucleoside-transport inhibitor, may be useful in potentiation of the effect of antitumor drugs.

Protease nexin-1, a potent thrombin inhibitor, is reduced around cerebral blood vessels in Alzheimer's disease

The clotting protease thrombin might contribute to the pathophysiology of central nervous system (CNS) injury and certain diseases by its ability to retract processes on neurons and astrocytes and to stimulate astrocyte proliferation. Protease nexin-1 (PN-1) is a 43 kDa thrombin inhibitor found predominantly in the brain where much of it resides around capillaries and large blood vessels. This location of PN-1 prompted the hypothesis that it may play a protective role against extravasated thrombin released following cerebrovascular injury or under certain pathological conditions. Recent studies indicated that the levels of PN-1 are markedly reduced in the postmortem brains of patients with Alzheimer's disease (AD). It was suggested that this reduction in PN-1 levels was due to the sequestration of PN-1 by extravasated thrombin. In the present study we examined the specific nature of this reduction by immunohistochemical staining of sections from control and AD brains using PN-1 specific antibodies. We show that the levels of PN-1 immunoreactivity around blood vessels and the number of blood vessels exhibiting PN-1 immunoreactivity were markedly reduced in the brains of patients with AD compared to age-matched controls; this reduction was reflected by a decrease in the levels of PN-1 activity and PN-1 protein. Thus an imbalance between PN-1 and thrombin may be a contributing factor in the pathology of AD.

Effects of the calcium channel blockers, diltiazem and Ro 40-5967, on systemic haemodynamics and plasma noradrenaline levels in conscious dogs with pacing-induced heart failure

1. Calcium channel blockers increase cardiovascular morbidity and mortality in patients with left ventricular dysfunction. These adverse effects are probably related to the negative inotropic effect of calcium channel blockers and/or a neurohormonal activation. 2. The present study was designed to examine, in conscious dogs, the acute haemodynamic and sympathetic effects of diltiazem and Ro 40-5967 (a novel calcium channel blocker) in the control state and in heart failure. 3. Thirteen dogs were instrumented with a micromanometer and an aortic catheter. After completion of experiments in the control state, heart failure was induced by right ventricular pacing (250 beats min-1, 3 weeks). Diltiazem and Ro 40-5967 were given intravenously (0.8 mg kg-1 and 1.0 mg kg-1 respectively). Cardiac output was measured by a thermodilution technique. 4. In the control state, both agents decreased similarly mean aortic pressure with significant increases in heart rate, cardiac output (both +1.0 l min-1 and P < 0.001) and plasma noradrenaline (both +55%) without changes in left ventricular dP/dtmax. In heart failure, for matched decreases in mean aortic pressure, neither diltiazem nor Ro 40-5967 changed heart rate significantly; diltiazem decreased cardiac output (-0.3 l min-1, P < 0.02) and dP/dtmax (-14%, P < 0.001) while Ro 40-5967 still increased cardiac output (+0.3 l min-1, P < 0.02) although the increased amount was smaller than in the control state. Plasma noradrenaline level was increased more during diltiazem infusion (+120%) than during Ro 40-5967 infusion (+38%, P < 0.001). 5. Diltiazem and Ro 40-5967 have similar haemodynamic and sympathetic effects in the control state.Heart failure alters haemodynamic and sympathetic responses to both calcium channel blockers but the magnitude of the alteration appears to be different. Diltiazem exerts a depressant effect on cardiac function which cannot be overcome by its vasodilator effect and sympathetic stimulation, while Ro 40-5967 has little effect on cardiac function. These data suggest that novel calcium channel blockers with less depressant effect may not be detrimental in heart failure.

Receptor tyrosine phosphatase R-PTP-alpha is tyrosine-phosphorylated and associated with the adaptor protein Grb2

Receptor tyrosine phosphatases (R-PTPases) have generated interest because of their suspected involvement in cellular signal transduction. The adaptor protein Grb2 has been implicated in coupling receptor tyrosine kinases to Ras. We report that a ubiquitous R-PTPase, R-PTP-alpha, is tyrosine-phosphorylated and associated in vivo with the Grb2 protein. This association can be reproduced in stably and transiently transfected cells, as well as in vitro using recombinant Grb2 protein. Association requires the presence of an intact SH2 domain in Grb2, as well as tyrosine phosphorylation of R-PTP-alpha. This observation links a receptor tyrosine phosphatase with a key component of a central cellular signalling pathway and provides a basis for addressing R-PTP-alpha function.

The effects of radiofrequency (< 30 MHz) radiation in humans

121 workers who were exposed to RFR (< 30 MHz) over one year were examined. They were divided into two groups: one group was exposed to high electric field intensity (> or = 100 V/m), another to low intensity (< 100 V/m) and both groups were compared to control subjects. No significant changes in the functioning of the autonomic nervous system and blood parameters (Hb, WBC and blood platelets) occurred in the exposed subjects of either group. Some changes in ECG (ST-T interval and abnormal heart rate) were observed in the group exposed to high intensity (> or = 100 V/m) radiation. 100 V/m is suggested as an exposure limit for RF (< 30 MHz) radiation.

[Analytical method of guiqi mixture and its main ingredient Astragalus root]

Chuanxiog Rhizome, Chinese Angelica Root and Scrophularia Root in Guiqi mixture have been identified by TLC. A TLC-densitometric method for determining astragalosied in the patent medicine and its main ingredient Astragalus Root has been established. This method is sensitive and highly reproducible, with RSD under 3.0% and recovery over 98%.

Treatment of stage IE primary lymphoma of bone

PURPOSE

A retrospective analysis was performed to assess the efficacy of various treatments of Stage IE primary non-Hodgkins lymphoma of bone.

METHODS AND MATERIALS

Sixty-three patients with Stage IE primary non-Hodgkins lymphoma of bone (single osseous focus) were seen at our institution between the years 1970 and 1989. Information was obtained regarding each patients' presentation and clinical course. The histology was reviewed in all patients. Modern immunohistochemical stains were performed on each case with available paraffin-embedded tissue.

RESULTS

The histologic classification of the tumors was as follows: 43 diffuse large cell, 13 diffuse mixed cell, 3 small noncleaved, and 4 unclassified. The most common presenting symptom was pain (97%) and the following bony sites were involved: 36 long bone, 9 flat bone, 13 spine, and 5 pelvis. Of the 63 cases, 50 were treated with radiation alone, 10 with chemotherapy and radiation, 2 with chemotherapy alone, and 1 with surgery alone. Univariate analysis revealed a suggestion of an improved 5-year disease-free survival for patients treated with chemotherapy and radiation vs. radiation alone (90% vs. 57% respectively, p = .08). Multivariate analysis (controlling for extent of initial evaluation, extent of pathological evaluation and other potential prognostic factors) showed that neither treatment resulted in superior outcome with respect to disease-free survival, disease specific survival, or overall survival, however, doses of radiation greater than 4000 cGy resulted in improved overall survival compared to lower doses (p = 0.01).

CONCLUSION

This study supports the use of primary RT (> 4000 cGy) for Stage IE PLB, however, the addition of chemotherapy to the radiotherapeutic management may decrease the initial relapse rate of some patients. Future studies should address this question.

Malignant tracheoesophageal fistula in patients with esophageal cancer

BACKGROUND

Patients with esophageal cancer and a malignant tracheoesophageal fistula (TEF) have an extremely poor prognosis. Additionally, these patients often are denied treatment with radiation therapy because there is concern that these treatments may increase the size and associated problems of the TEF.

METHODS

To determine the appropriate treatment (use of radiation therapy) for patients with esophageal cancer and malignant TEF, a review was performed of all such cases seen at the Mayo Clinic between 1971 and 1991.

RESULTS

Between 1971 and 1991, 41 patients with malignant TEF arising as a result of esophageal cancer were seen at the Mayo Clinic in Rochester. Twenty-eight of these cancers were locally recurrent, and this group of patients had a uniformly poor outcome (median survival time, 1.4 months). Thirteen patients had a malignant TEF and had not received previous treatment for their esophageal cancer. The median survival length was 4 months for this group of patients. Of the 41 patients in this study, 10 received radiation therapy for their malignant TEF (30-66 Gy). The median survival length of this group of patients was 4.8 months. Six of these 10 patients died of metastatic disease (median survival length, 9 months), and there was no evidence of progression of the local tumor. Four of these 10 patients died of local progression of the malignancy (median survival length, 3 months).

CONCLUSIONS

Radiation therapy did not increase the severity of the TEF. The authors conclude that radiation therapy can be administered safely in patients with TEF resulting from esophageal cancer. In some patients, radiation treatment may contribute to stabilization of the local tumor process (60% of patients treated with radiation therapy died of metastatic disease without local progression of tumor); however, all patients in this study eventually died of esophageal cancer.