Multiple drug-resistance in variant of a human non-small cell lung carcinoma cell line,DLKP-A

A 300-fold adriamycin resistant variant (DLKP-A) of the human lung squamous cell carcinoma line DLKP was established by stepwise selection in increasing concentrations of adriamycin. Different levels of cross-resistance were observed towards VP-16, VM-26, colchicine, vincristine and, somewhat unexpectedly, cis-platin. Resistance was stable for at least 3 months in culture in the absence of drug. P-glycoprotein overexpression was detected by immunofluorescence and Western Blotting, and a direct causal role for P-glycoprotein overexpression in the resistant phenotype was established by transfection with an mdr1 specific antisense oligonucleotide. A modified cryopreservation procedure was necessary for the resistant variant line. The resistant population displays clonal heterogeneity with respect to resistance level. A higher frequency of double minute chromosomes was observed in DLKP-A when compared with the parental cell line.Abbreviations ADR adriamycin - COLH colchicine - C-PT cis-platin - MDR multidrug resistance - NSCLC non-small cell lung carcinoma - VCR vincristine - VP-16 etoposide - VM-26 tenoposide     

Annual Change of Primary Resistance to Clarithromycin among Helicobacter pylori Isolates from 1996 through 2008 in Japan

Background: Recent studies have shown that the combination of proton pump inhibitor, amoxicillin and clarithromycin is one of the best choices for Helicobacter pylori eradication therapy. However, increasing number of cases of H. pylori infection showing resistance to clarithromycin therapy has been reported and this is currently the main cause of eradication failure. We investigated the annual changes of the antimicrobial susceptibility to clarithromycin, amoxicillin and minocycline during a period of 12 years in Japan. Methods: This study comprised 3521 patients (mean age (SD), 55.4 (13.7) years‐old, 2467 males and 1054 females) positive for H. pylori as assessed by microaerobic bacterial culture from 1996 through 2008. All patients were previously untreated for H. pylori and were enrolled in the study to assess primary resistance to the three antibiotics. Results: The overall primary resistance to clarithromycin, amoxicillin and minocycline were 16.4%, (577/3521), 0.03% (1/3521) and 0.06% (2/3521), respectively. From1996 through 2004, the resistance rate to clarithromycin increased gradually to approximately 30% and then it remained without marked fluctuation since 2004. Analysis by gender showed a significant increase (p < .0001) in resistance rate to clarithromycin among females (217/1057, 20.6%) compared to males (360/2467, 14.6%). Analysis by age, disclosed significantly (p < .0001) higher resistance rate to clarithromycin in patients of more than 65‐years‐old compared to the younger population. Conclusions: The resistance rate of H. pylori infection to clarithromycin in Japan has increased gradually to approximately 30% from 1996 through 2004, and remained unchanged since 2004. Elderly and females were at high risk of having resistance to clarithromycin. Our results suggested that the level of clarithromycin resistance in Japan has now risen to the point where it should no longer be used as empiric therapy.     

A Randomized Controlled Trial: Efficacy and Safety of Azithromycin,Ofloxacin, Bismuth,and Omeprazole Compared With Amoxicillin,Clarithromycin, Bismuth,and Omeprazole as Second‐Line Therapy in Patients With Helicobacter pylori Infection

Background: Helicobacter pylori infection of the stomach is widespread among human populations and is considered to play a major role in the pathogenesis of various diseases such as peptic ulcer, adenocarcinoma, and mucosa associated lymphoid tissue (MALT) lymphoma of the stomach. To increase H. pylori eradication rate without increasing bacterial resistance, various regimens have been recommended. Commonly the association of at least two antibiotics with a proton‐pump inhibitor is used. The treatment regimens for second‐line therapy, suggested in studies from the western world may not be ideal in Iran. Aim: In this study, we evaluated the safety and efficacy of a new quadruple therapy regimen and compared it with the standard second‐line treatment for H. pylori eradication. Methods: We selected 220 H. pylori positive patients, with a clear indication of eradication therapy, who did not respond to a 2 weeks treatment with metronidazole, amoxicillin, omeprazole, and bismuth. They were randomized into two groups. Group A (n = 110) were treated with azithromycin, ofloxacin, bismuth, and omeprazole and group B (n = 110) with amoxicillin, clarithromycin, bismuth, and omeprazole for 2 weeks. Four weeks after the end of treatment, urea breath test was performed for all subjects to confirm eradication. Results: In intention‐to‐treat analysis, the rate of H. pylori eradication in groups A and B was 77.3% (85/110) and 64.5% (71/110) respectively (p = .027). In per‐protocol analysis, the rate of H. pylori eradication in groups A and B was 86.7 and 74.7%, respectively (p = .026). The incidence of poor compliance was lower, although not significantly so, in group A than group B (3.5 vs 4.3%). No major adverse events occurred in both groups. Conclusion: Two weeks of treatment with ofloxacin, azithromycin, omeprazole, and bismuth is an effective and safe regimen for H. pylori eradication as second‐line therapy.     

Low-temperature resistance in Polylepis tarapacana, a tree growing at the highest altitudes in the world

The Polylepis tarapacana forests found in Bolivia are unique with respect to their altitudinal distribution (4200–5200 m). Given the extreme environmental conditions that characterize these altitudes, this species has to rely on distinct mechanisms to survive stressful temperatures. The purpose of this study was to determine low‐temperature resistance mechanisms in P. tarapacana. Tissue was sampled for carbohydrate and proline contents and micro‐climatic measurements were made at two altitudes, 4300 and 4850 m, during both the dry cold and wet warm seasons. Supercooling capacity (?3 to ?6 °C for the cold dry and ?7 to ?9 °C for the wet warm season) and injury temperatures (?18 to ?23 °C for both seasons), determined in the laboratory, indicate that P. tarapacana is a frost‐tolerant species. On the other hand, an increase in supercooling capacity, as the result of significant increase in total soluble sugar and proline contents, occurs during the wet warm season as a consequence of higher metabolic activity. Hence, P. tarapacana, a frost‐tolerant species during the colder unfavourable season, is able to avoid freezing during the more favourable season when minimum night‐time temperatures are not as extreme.     

Impact of Quadruple Regimen of Clarithromycin Added to Metronidazole-Containing Triple Therapy Against Helicobacter pylori Infection Following Clarithromycin-Containing Triple-Therapy Failure

Background: The establishment of an optimal second-line regimen for Helicobacter pylori infection is required. Although quadruple therapy should overcome resistance to either clarithromycin or metronidazole, the effects of a quadruple regimen in second-line therapy are unknown. This study aims to evaluate the efficacy of triple therapy composed of proton pump inhibitor/amoxicillin plus metronidazole with the combined additive effects of clarithromycin as a second-line quadruple therapy against H. pylori infection.
Materials and Methods: Participants were 104 patients in whom first-line therapy containing proton pump inhibitor-amoxicillin-clarithromycin failed. Before starting second-line therapy, patients underwent endoscopy to obtain H. pylori strain for antibiotic susceptibility tests. Patients were randomized to receive rabeprazole (10 mg), amoxicillin (750 mg), and metronidazole (250 mg), either with clarithromycin (200 mg; RAMC group) or without (RAM group); all treatments were administered twice daily for 7 days. H. pylori eradication was confirmed by ¹³C-urea breath tests performed 2 to 3 months post-therapy.
Results: As shown by intention-to-treat/per-protocol analyses, the cure rates for H. pylori infection were 88.5%/93.9% and 82.7%/84.3% for the RAMC and RAM groups. Although the study probably had an insufficient power to show a significant difference between the cure rates of the two regimens, the eradication rates showed a clear trend in favor of the RAMC group. There were no severe side-effects in any group.
Conclusions: In Japan, the RAMC regimen is thought to be a promising alternative strategy for second-line eradication of H. pylori infection.     

Dual-Priming Oligonucleotide-Based Multiplex PCR for the Detection of Helicobacter pylori and Determination of Clarithromycin Resistance with Gastric Biopsy Specimens

Background:  Assessment of Helicobacter pylori ( H. pylori ) clarithromycin resistance has rarely been performed routinely despite an increasing resistance rate. Our aim was to develop and evaluate the use of dual-priming oligonucleotide (DPO)-based multiplex polymerase chain reaction (PCR) to detect point mutations in the 23S rRNA gene responsible for clarithromycin resistance of H. pylori.
Materials and Methods:  Gastric biopsy specimens from 212 untreated patients with dyspepsia were examined by culture, histology, and DPO-based multiplex PCR. A disk diffusion test and E-test were used for performing phenotypic antibiotic susceptibility tests.
Results:  Among the biopsy specimens tested, 22.2% (47/212), 42.5% (90/212), and 41.5% (88/212) of the specimens were classified as H. pylori positive by culture, histology, and DPO-based multiplex PCR, respectively. Among 96 strains identified by either culture or DPO-based multiplex PCR, 80 strains were clarithromycin-susceptible and 16 strains (16.7%) were clarithromycin-resistant. There was 94.1% (32/34) concordance between phenotypic susceptibility tests and DPO-based multiplex PCR. In two patients with discrepant results, only DPO-based multiplex PCR detected clarithromycin-resistant strains. DPO-based multiplex PCR identified additional 49 clarithromycin-resistant or clarithromycin-susceptible H. pylori among 165 culture-negative specimens.
Conclusions:  DPO-based multiplex PCR can be used as a practical method for the detection of H. pylori infection and the determination of clarithromycin susceptibility in addition to phenotypic antimicrobial susceptibility tests.     

Clarithromycin, a cytochrome P450 inhibitor, can reverse mefloquine resistance in Plasmodium yoelii nigeriensis- infected Swiss mice

During the last 2 decades there have been numerous reports of the emergence of mefloquine resistance in Southeast Asia and nearly 50% resistance is reported in Thailand. A World Health Organization report (2001) considers mefloquine as an important component of ACT (artesunate+mefloquine) which is the first line of treatment for the control of uncomplicated/multi-drug resistant (MDR) Plasmodium falciparum malaria. In view of the emergence of resistance towards this drug, it is proposed to develop new drug combinations to prolong the protective life of this drug. Prior studies have suggested that mefloquine resistance can be overcome by a variety of agents such as ketoconazole, cyproheptadine, penfluridol, Icajine and NP30. The present investigation reports that clarithromycin (CLTR), a new macrolide, being a potent inhibitor of Cyt. P450 3A4, can exert significant resistance reversal action against mefloquine resistance of plasmodia. Experiments were carried out to find out the curative dose of CLTR against multi-drug resistant P. yoelii nigeriensis. Mefloquine (MFQ) and clarithromycin (CLTR) combinations have been used for the treatment of this MDR parasite. Different dose combinations of these two drugs were given to the infected mice on day 0 (prophylactic) and day 1 with established infection (therapeutic) to see the combined effect of these combinations against the MDR malaria infection. With a dose of 32 mg/kg MFQ and 225 mg/kg CLTR, 100% cure was observed, while in single drug groups, treated with MFQ or CLTR, the cure was zero and 40% respectively. Therapeutically, MFQ and CLTR combinations 32+300 mg/kg doses cleared the established parasitaemia on day 10. Single treatment with MFQ or CLTR showed considerable suppression of parasitaemia on day 14 but neither was curative. Follow-up of therapeutically treated mice showed enhanced anti-malarial action as reflected by their 100% clearance of parasitaemia. The present study reveals that CLTR is a useful antibiotic to be used as companion drug with mefloquine in order to overcome mefloquine resistance in plasmodia.     

Double-blind, Multicenter, Placebo-Controlled Evaluation Of Clarithromycin And Omeprazole For Helicobacter Pylori-Associated Duodenal Ulcer

Background. Eradication of Helicobacter pylori leads to faster ulcer healing and a significant decrease in ulcer recurrence. Clarithromycin is the most effective monotherapy for eradicating H. pylori from the gastric mucosa, and omeprazole frequently is used for the treatment of duodenal ulcer disease, prompting the interest to investigate rigorously the combination of clarithromycin and omeprazole for eradicating H. pylori. Materials and Methods. The aim of this double-blind, randomized, multicenter (n=30), multinational (n=10) study was to compare clarithromycin and omeprazole with omeprazole monotherapy for the eradication of H. pylori from the gastric mucosa, endoscopic healing, and reduction of symptoms and ulcer recurrence in patients with active duodenal ulcer. Patients with active duodenal ulcer associated with H. pylori infection were randomized to receive omeprazole, 40 mg every morning for 14 days, with either clarithromycin, 500 mg, or placebo three times daily, which was followed by omeprazole, 20 mg every morning for 14 days. Patients underwent endoscopy before enrolling in the study, immediately after finishing treatment, and at 4- to 6-week and 6-month follow-up evaluations or at the recurrence of symptoms. Results. Two hundred and eight patients with active duodenal ulcer associated with confirmed H. pylori infection were randomized to treatment with either clarithromycin and omeprazole (n=102) or omeprazole and placebo (n=106). Four to six weeks after treatment was completed, H. pylori was eradicated in 74% (95% confidence interval, 63.0%–82.4%) of patients receiving clarithromycin and omeprazole, compared with 1% (0.0%–6.2%) of patients receiving omeprazole monotherapy (p < .001). Clarithromycin resistance developed in eight patients treated with clarithromycin and omeprazole and in none given omeprazole and placebo. Ulcers, which were healed following treatment in more than 95% of study patients, recurred by the 6-month follow-up visit in 10% (5%–19%) of dual therapy recipients, compared with 50% (39%–61%) of those who took omeprazole alone (p <.001). Conclusion. Clarithromycin and omeprazole dual therapy is simple and well-tolerated and leads to consistently high eradication rates for patients with duodenal ulcer associated with H. pylori infection.     

Changes in the electrochemical interface as a result of the growth of Pseudomonas fluorescens biofilms on gold

In this study, variations in corrosion potential and polarization resistance of thin-film gold electrodes as a result of the growth of Pseudomonas fluorescens biofilms on them are presented. The growth of the volumetric cell fraction of biofilms, as determined by optical sectioning and digital image analysis of phase-contrast images, was found to be exponential during at least 10 hours of incubation. As a consequence of biofilm growth, an exponential decay of the corrosion potential of gold was observed. Most importantly, an increase in polarization resistance of the interface was observed following a strong linear dependence on the mean thickness of biofilms (r = 0.997), as a consequence of oxygen consumption and diffusion limitations. The results presented indicate that the measurement of polarization resistance may be a suitable technique that could be applied easily in industrial or biotechnological systems for monitoring the formation of biofilms.     

Formulation and Evaluation of Gastroretentive Dosage Forms of Clarithromycin

The purpose of this research was to develop the hydrodynamically balanced delivery system of Clarithromycin (CLA) which, after oral administration should have the ability to prolong gastric residence time with the desired in vitro release profile for the localized action in the stomach, in the treatment of Helicobacter pylori (H.pylori) mediated peptic ulcer. By applying wet granulation technique floating tablets of Clarithromycin were prepared. The proportion of sodium bicarbonate was varied to get the least possible lag time, also the polymer part varied to get the desired release. In vivo radiographic studies were performed with Barium sulphate loaded formulation to justify the increased gastric residence time of the dosage form in the stomach, based on the floating principle. The formulation developed using 66.2% Clarithromycin, 12% HPMC K4M polymer, 8% sodium bicarbonate gave floating lag time less than 3 min with a floating time of 12 h, and an in vitro release profile very near to the desired release. X-ray studies showed the enhanced gastric residence time of the tablet to 220 ± 30 min. The mechanism of release of Clarithromycin from the floating tablets is anomalous diffusion transport and follows zero order kinetics. In vivo radiographic studies suggest that the tablet has increased gastric residence time for the effective localized action of the antibiotic (Clarithromycin) in the treatment of H.pylori mediated peptic ulcer.     

阿莫西林、雷贝拉唑联合克拉霉素治疗Hp 相关消化性溃疡的疗效

目的：探讨阿莫西林、雷贝拉唑联合克拉霉素治疗Hp相关性消化性溃疡的疗效及对患者生活质量的影响,为临床治疗提供 依据。方法：选择2013 年4 月-2015 年4 月本院收治的Hp 相关消化性溃疡患者120 例,根据治疗方法不同将患者分为研究组和 对照组,每组各60 例。研究组采用阿莫西林、雷贝拉唑及克拉霉素联合治疗,对照组采用奥美拉唑单药治疗。观察并比较两组患 者的临床疗效、SDS 评分及SAS 评分。结果：研究组总有效率显著高于对照组,差异有统计学意义（P<0.05）;研究组SDS、SAS 评 分低于对照组,差异有统计学意义（P<0.05）。结论：采用阿莫西林、雷贝拉唑和克拉霉素联合治疗Hp 相关消化性溃疡具有较好的 临床疗效,能够显著改善患者的临床症状,提高生活质量,值得推广应用。     

Characterization of a stable,anchorage-dependent clone obtained from a spontaneously transformed mouse cell line

Summary A variant nontransformed clone, I21, was selected from the spontaneously transformed mouse fibroblast line, IT22. Selection was done by plating IT22 in methylcellulose and picking single cells after 2 d. Cultures derived from these single cells were selected again and one clone, I21, derived from the second round of selection was characterized extensively. I21 and IT22 have the same plating efficiency (PE) on plastic, but in agarose they differ by 1000-fold. In comparison to IT22, I21 has a normal morphological appearance, a lower saturation density, a higher viability in stationary phase, an increased doubling time, an increased chromosome content, and is unable to form tumors in nude mice. I21 has remained remarkably stable in culture and has not reverted to the transformed phenotype for at least 300 generations in culture. Over 100 clones of I21, expanded to 10⁶ cells, failed to show an increased PE in agarose. Even expansion of the rare colonies of I21 that grow in agarose failed to produce clones similar to IT22. The research was supported by the Medical Research Council and the National Cancer Institute of Canada. R. Godbout was supported by a 1967 Science Scholarship and by an MRC Studentship. B. L. Gallie is a Research Associate of the Ontario Cancer Treatment and Research Foundation.     

Comparison of One or Two Weeks of Lansoprazole, Amoxicillin, and Clarithromycin in the Treatment of Helicobacter pylori

Background The simplest, most effective, and least expensive Helicobacter pylori therapy remains to be determined. Two weeks of 30 mg lansoprazole bid, 1 gm amoxicillin bid, and 500 mg clarithromycin bid (LAC2) had been shown to be an effective therapy for H. pylori. The aim of this study was to assess whether 1 week of this regimen (LAC1) would have a similar efficacy.
Materials and Methods. H. pylori -positive patients assessed histologically, by rapid urease test, microbiologically, and by a ¹³C-urea breath test (¹³C-UBT) were randomized to receive either LAC1 or LAC2 in a single-center open study. Patients were interviewed 1 to 3 days after completion of therapy to evaluate adverse events and compliance. Efficacy was determined by ¹³C-UBT at least 4 weeks after antibiotic therapy.
Results. Seventy evaluable patients were randomized to receive LAC1 (n = 33) and LAC2 (n = 37). Of the 33 LAC1 patients, 30 (91%) were treated successfully (95% confidence interval (CI) = 76–98%), compared with 32 of 37 (86%) in the LAC2 group (95% CI = 71–96%). There was no difference in efficacy between the two groups (Fisher's exact test p = 1.0; 95% CI =–10.3%–19.2%). Patients taking LAC1 experienced significantly fewer severe adverse events than those taking LAC2 (Mann-Whitney U test). One of 64 patients had primary resistance to clarithromycin, and treatment was unsuccessful in this case. Six of the 7 remaining treatment failures developed secondary resistance to clarithromycin.
Conclusions. LAC1 is as effective as LAC2 and is associated with less toxicity. Posttreatment clarithromycin resistance is common in patients who do not experience success with therapy.     

Z6／陕7859胚培养再生植株的细胞遗传学研究与易位系选育

二体附加系Ｚ６携带抗大麦黄矮病毒病基因,为了将其抗性导入小麦,将Ｚ６与普通小麦陕７８５９杂交,杂种Ｆ１经幼胚培养诱导形成再生植株,对再生植株及后代进行抗性鉴定,农艺性状考察及对ＳＣ２部分抗病植株花粉母细胞减数分裂期染色体行为进行了观察。结果表明,（１）ＳＣ２不同单株间存在染色体数目,结构的变异。（２）同一再生植株后代的不同单株,染色体数目可能相同,但染色体组成及减数分裂期行为可心不同,致使后代抗性     

Characterization of a human colonic adenocarcinoma cell line,LS123

Summary An epithelial cell line, LS123, was established in 1974 from the second in a series of three primary colonic tumors resected from a Caucasian female. The cell line is aneuploid, releases low concentrations of carcinoembryonic antigen (CEA), fails to grow progressively in nude mice, and forms colonies only in enriched semisolid medium developed for tumor stem cells. LS123 cells grow on confluent cell monolayers and in either low serum or serum-free medium. In the chick embryonic skin assay, LS123 cells grew as a well-differentiated abnormal colonic epithelium with little mitotic activity but with some indication of invasion. On floating collagen gels LS123 cells formed a one to three-cell-layer-thick undifferentiated epithelial sheet. The apparent low invasiveness of the cells of this line is supported by the patient's history of three primary colon tumors without systemic metastases during the past 30 yr. Therefore, although LS123 cells possess several properties associated with neoplasia, they have little invasive potential. Thus, LS123 cells may represent an important model for the study of human colon cancer. Presented in part at the 33rd Annual Meeting of the Tissue Culture Association, San Diego, CA, June 6–10, 1982. The work has been partially supported by U.S. Public Health Service Grants CA23871 (L. P. R.), CA24024 and RCDAK04-CA00579 (B. H. T.), and CA27124 and CA22370 (B. D. K.); the latter was awarded through the National Large Bowel Cancer Project.     

Clarithromycin resistance in Helicobacter pylori strains isolated from French children: prevalence of the different mutations and coexistence of clones harboring two different mutations in the same biopsy

BACKGROUND: The aim of our study was to assess the different mutations involved in clarithromycin-resistant Helicobacter pylori strains isolated from French children and their temporal trends. METHODS: The point mutations of H. pylori were detected by PCR followed by RFLP technique in 50 clarithromycin-resistant strains collected between 1993 and 2004 in France. RESULTS: Clarithromycin resistance was observed in 23% (50/217) of H. pylori isolates. Two mutations A2143G and A2142G in the 23S rRNA genes of H. pylori were detected. The former was found in 45/50 (90%) of isolates. The rate of resistance increased with time from 18.6% in the period 1993-1996 to 41.6% in 2001-2004. No significant difference was observed in the distribution of mutations during the same periods. No correlation was found between any mutation and age, sex, and ethnic origin of children. Furthermore, no significant differences in minimal inhibitory concentrations level were observed according to the different point mutations. In all cases, only one point mutation was present, except in two cases where two different mutations were found in two different clones from the same biopsy. CONCLUSION: The mutation A2143G is predominant in clarithromycin-resistant H. pylori strains isolated from children in France. We report for the first time the presence of two clarithromycin-resistant clones harboring two different mutations of the 23S rRNA genes present in the same biopsy specimen and genotypically identical as demonstrated by RAPD fingerprinting.     

葡萄花翅小卷蛾抗药性研究进展

葡萄花翅小卷蛾是葡萄上的重要害虫,具有多食性、多化性等生物学特点,抗逆能力极强。该虫起源于欧洲,现已入侵全球多个国家。葡萄花翅小卷蛾主要以幼虫取食葡萄花序、幼果和成熟果实,给葡萄生产造成重大损失;其危害有利于真菌的侵入,导致灰霉病、白粉病等病害大量发生,从而造成葡萄腐烂。由于该虫入侵风险极高,已被我国列为重要的进境检疫性有害生物。国外对葡萄花翅小卷蛾的防治主要采用化学杀虫剂,由于长期大量且不合理地使用化学杀虫剂,葡萄花翅小卷蛾已对多种不同类型的杀虫剂产生了抗药性。本研究总结了葡萄花翅小卷蛾的抗性测定方法、抗性现状及其抗性机理,同时结合国外葡萄花翅小卷蛾抗性和防治相关研究,提出该虫抗性治理策略,并对我国预防该虫的入侵提出建议。