Diagnosis of latent tuberculosis infection in bacille Calmette-Guérin vaccinated subjects in China by interferon-gamma ELISpot assay

OBJECTIVE

To evaluate the performance of an in-house interferon-gamma (IFN-γ) enzyme-linked immunospot (ELISpot) assay for the detection of latent tuberculosis infection (LTBI) in bacille Calmette-Guérin (BCG) vaccinated individuals with or without human immunodeficiency virus (HIV) infection.

METHODS

A total of 202 participants (93 HIV-infected and 109 non-infected) who received BCG vaccination at birth underwent tuberculin skin testing (TST) and T cell-based ELISpot assays. The performance of an in-house IFN-γ ELISpot assay (ELISpot) was evaluated by parallel comparison with the commercial IFN-γ release assay (IGRA) kit, T-SPOT®.TB, in 127 subjects. The effect of BCG vaccination on the ELISpot assay was prospectively determined by comparing the responses of IGRAs before and 3 months after BCG vaccination in 27 individuals.

RESULTS

High agreement between ELISpot and T-SPOT.TB was observed in both HIV-infected (92.47%, κ = 0.754) and non-HIV-infected subjects (97.06%, κ = 0.653). CD4(+) T-cell count does not affect Mycobacterium tuberculosis IFN-γ response as measured by both ELISpot and T-SPOT.TB. BCG vaccination resulted in 100% conversion of TST, but did not change responses to IGRAs.

CONCLUSION

The performance of this in-house ELISpot assay is comparable to commercial T-SPOT.TB in diagnosing LTBI. Both assays are useful for diagnosing LTBI in BCG-vaccinated subjects with or without HIV infection in a setting with a high prevalence of tuberculosis.

TAK-285, a Novel HER2/EGFR Inhibitor, Penetrates the CNS in Rats with an Intact Blood Brain Barrier (BBB)

Background: Approximately one third of patients with HER2-overexpressing (HER2+) metastatic breast cancer develop brain metastases. Treatment options for patients whose brain metastases have progressed after radiotherapy are urgently needed. The currently approved HER2-targeted therapies, trastuzumab and lapatinib, have generally shown limited activity against brain metastases, likely due to the limited brain penetration of these drugs. Brain penetration is mediated by multiple factors including drug permeability, tissue binding, and the expression of efflux transporters (P-gp and BCRP) and their interactions with the drug. TAK-285 is a novel, orally active, dual HER2/EGFR inhibitor currently under clinical development. In this nonclinical work, we evaluated the permeability, interactions with efflux transporters, and brain penetration of TAK-285, along with lapatinib and neratinib, using in vitro and animal models.Material and Methods: The first study evaluated the permeability of TAK-285, lapatinib, and neratinib and their interactions with efflux transporters using the Caco-2 cell monolayer system in the absence or presence of efflux pump inhibitors. The second study evaluated brain penetration of TAK-285, lapatinib and neratinib after a single oral administration in rats with an intact BBB.Results: In the Caco-2 cell model, TAK-285 showed high permeability with an efflux ratio of 1.7, indicating it is not a substrate for efflux pumps. The efflux pump inhibitors LY335979 (an inhibitor of P-gp), Ko143 (an inhibitor of BCRP), and GF120918 (an inhibitor of BCRP and P-gp) had no marked effect on the efflux ratio of TAK-285, further confirming that TAK-285 is not a substrate for P-gp and BCRP. Lapatinib and neratinib showed low to medium permeability and appeared to be substrates for P-gp/BCRP in this testing system. In the rat brain penetration study, the brain-to-plasma AUC ratio for total (free and bound) TAK-285, lapatinib, and neratinib was 0.202, 0.0243, and 0.0263, respectively.Discussion: These nonclinical studies showed that, unlike lapatinib and neratinib, TAK-285 is not a substrate for the efflux transporters, P-gp and BCRP. Based on published information, all of the approved receptor tyrosine kinase inhibitors are substrates for efflux transporters. Additionally, in rats with an intact BBB, the brain-to-plasma AUC ratio for TAK-285 was substantially higher than that of lapatinib and neratinib. The AUC ratios observed in this study for lapatinib and neratinib are similar to the proportion of blood volume in the rat brain (ie, outside the CNS) relative to the total rat brain volume. This suggests the actual brain-to-plasma AUC ratio for TAK-285 in rats may be much greater than 8-fold of that of lapatinib and neratinib calculated based on these measured AUC ratios. Consequently, TAK-285 may have a unique role in the treatment of brain lesions in patients with HER2- or EGFR-dependent tumors. Furthermore, TAK-285 may not be subject to drug resistance conferred by efflux transporters.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 5098.

A new soft x-ray pulse height analysis array in the HL-2A tokamak

A new soft x-ray pulse height analysis (PHA) array including nine independent subsystems, on basis of a nonconventional software multichannel analysis system and a silicon drift detector (SDD) linear array consisting of nine high performance SDD detectors, has been developed in the HL-2A tokamak. The use of SDD has greatly improved the measurement accuracy and the spatiotemporal resolutions of the soft x-ray PHA system. Since the ratio of peak to background counts obtained from the SDD PHA system is very high, p/b > or = 3000, the soft x-ray spectra measured by the SDD PHA system can approximatively be regarded as electron velocity distribution. The electron velocity distribution can be well derived in the pure ohmic and auxiliary heating discharges. The performance of the new soft x-ray PHA array and the first experimental results with some discussions are presented.

Cross-talking between bone marrow-derived cells and lung cancer cells

e19068

Background: Disseminated cancer cells may initially require local nutrients and growth factors to thrive and survive in bone marrow. However, data on the influence of bone marrow derived cells(BMDC, also called bone stromal cells in some publication) on lung cancer cells is largely unexplored. This study is to explore the effect from bone marrow derived cells on biological behavior of lung cancer cells. Methods: The difference among lung cancer cell lines in their abilities to bone metastasis was tested using SCID animal model. Supernatant of bone marrow aspiration(BM) and condition medium from human bone stromal cells(BSC) were used to study the activity of bone stromal factors. Affymetrix gene chip U133A 2.0 was used to study the gene expression profile of H460 cells, after exposure to secreted proteins from bone stromal cells. Results: In accordance with other literature repors, H460 was found with high bone metastasis potential, while SPC-A1 and A549 cells were low bone metastasis lung cancer cells. We found bone stromal factors significantly increased the proliferation, invasion, adhesion and expression of angiogenosis-related factors, and inhibited the apoptosis for high bone metastasis H460 lung cancer cells. These biologic effects were not seen in SPC-A1 or A549 cells, which are low bone metastasis lung cancer cells. Adhesion of H460 cells to bone stromal cells consistently up-regulated 31 genes. Ontoexpress software showed main function of 31 genes were associated with signal transduction pathways(5 genes), and adhesion molecule(5 genes), including integrin b3 and ADAMTS-1, two potential targets related with bone metastasis. Conclusions: We concluded bone marrow derived cells had a profound effect on biological behavior of lung cancers, therefore favoring the growth of lung cancer cells in bone.

No significant financial relationships to disclose.

An exploration of Pap smear history and behavior of patients with newly diagnosed cervical cancer in Taiwan

e20582

Background: The national health insurance policy has provided a yearly Pap smear for women >= 30 years old since 1994 in Taiwan, yet the coverage rate is still unsatisfactory. The purpose of this study is (1) to investigate the Pap smear screening history of women newly diagnosed with cervical cancer and (2) to examine factors that influence participation in Pap smear screening program in these women. Methods: Patients primarily treated for cervical cancer at Chang Gung Memorial Hospital between November 2006 and June 2007 were enrolled into this prospective study. Questionnaires included (1) socio-demographic data, and (2) knowledge on Pap smear and cervical cancer. Results: Two hundred sixty-nine patients were eligible for analysis. The median age was 51 years old (range, 25–83). Of the 269 patients, 147 (54.6%) had never had a Pap smear before diagnosis, and 35 (13.0%) did not know about Pap smear. Socio-demographic factors that significantly influenced number of previous Pap smear screening (0 vs >=1) were education level, income less than 600 U.S. dollars per month, menopaused, multiple sexual partners, and increase number of sexual partners of the male consort. Of the 147 never received Pap women, the most common reasons were thought that Pap smear screening was not necessary (46.3%), embarrassment (42.0%), busy (43.5%), and worry about the screening findings (20.4%). Of the 122 patients who have received Pap smear, 56.6% patients thought that Pap smear screening was necessary, 35.2% patients worried about the disease, 24.6% were alert on their check-ups, and 20.5% did the screening for the convenience to nearby clinics. Conclusions: Public health organizations in Taiwan should put more efforts to provide women in low education level, low income and multiple sexual partners with information on Pap smear.

No significant financial relationships to disclose.

Development of silver carp (Hypophthalmichthys molitrix) and bighead carp (Aristichthys nobilis) genetic maps using microsatellite and AFLP markers and a pseudo-testcross strategy

Silver carp (Hypophthalmichthys molitrix) and bighead carp (Aristichthys nobilis) are two of the four most important pond-cultured fish species inhabiting the major river basins of China. In the present study, genetic maps of silver carp and bighead carp were constructed using microsatellite and AFLP markers and a two-way pseudo-testcross strategy. To create the maps, 60 individuals were obtained from a cross of a single bighead carp (female) and a single silver carp (male). The silver carp map consisted of 271 markers (48 microsatellites and 223 AFLPs) that were assembled into 27 linkage groups, of which 22 contained at least four markers. The total length of the silver carp map was 952.2 cM, covering 82.8% of the estimated genome size. The bighead carp map consisted of 153 markers (27 microsatellites and 126 AFLPs) which were organized into 30 linkage groups, of which 19 contained at least four markers. The total length of the bighead carp map was 852.0 cM, covering 70.5% of the estimated genome size. Eighteen microsatellite markers were common to both maps. These maps will contribute to discovery of genes and genetic regions controlling traits in the two species of carp.

A heterologous prime-boost vaccination regime using DNA and a vaccinia virus, both expressing GRA4, induced protective immunity against Toxoplasma gondii infection in mice

SUMMARYThe dense granule antigen 4 (GRA4) is known as an immundominant antigen of Toxoplasma gondii and, therefore, is considered as a vaccine candidate. For further evaluation of its vaccine effect, a recombinant plasmid and vaccinia virus, both expressing GRA4, were constructed, and a heterologous prime-boost vaccination regime was performed in a mouse model. The mice immunized with the heterologous prime-boost vaccination regime showed a high level of specific antibody response against GRA4 and a significantly high level of gamma interferon (IFN-gamma) production and survived completely against a subsequent challenge infection with a lethal dose of T. gondii. In addition, the formation of cysts was inhibited in the mice vaccinated with the heterologous prime-boost vaccination regime. These results demonstrate that the heterologous prime-boost vaccination regime using DNA and a vaccinia virus, both expressing GRA4, could induce both humoral and cellular immune responses and provide effective protection against lethal acute and chronic T. gondii infections in mice.

N terminus determinants of MinC from Neisseria gonorrhoeae mediate interaction with FtsZ but do not affect interaction with MinD or homodimerization

While bacterial cell division has been widely studied in rod-shaped bacteria, the mechanism of cell division in round (coccal) bacteria remains largely enigmatic. In the present study, interaction between the cell division inhibitor MinC from Neisseria gonorrhoeae (MinC(Ng)) and the gonococcal cell division proteins MinD(Ng) and FtsZ(Ng) are demonstrated. Protein truncation and site-directed mutagenic approaches determined which N-terminal residues were essential for cell division inhibition by MinC(Ng) using cell morphology as an indicator of protein functionality. Truncation from or mutation at the 13th amino acid of the N terminus of MinC(Ng) resulted in loss of protein function. Bioinformatic analyses predicted that point mutations of L35P and L68P would affect the alpha-helical conformation of the protein and we experimentally showed that these mutations alter the functionality of MinC(Ng). The bacterial two-hybrid system showed that interaction of MinC(Ng) with FtsZ(Ng) is abrogated upon truncation of 13 N-terminal residues while MinC(Ng)-MinD(Ng) interaction or MinC(Ng) homodimerization is unaffected. These data confirm interactions among gonococcal cell division proteins and determine the necessity of the 13th amino acid for MinC(Ng) function.

Multicenter, randomized trial comparing a combined gemcitabine and cisplatin 3-week regimen with a 4-week regimen in non-small cell lung cancer (NSCLC) patients

17062

Background: This multicenter, randomized Phase II study (B9E-GH-JHSE) was aimed to compare the efficacy and safety of a gemcitabine-cisplatin combination over a 3-week schedule versus a 4-week schedule as first line treatment for Chinese patients with advanced NSCLC. Methods: Patients (pts) with pathologically or histologically confirmed stage IIIB/IV NSCLC not amenable to curative surgery, and presenting at least one measurable lesion were eligible for this study. Pts were randomized to receive cisplatin (cis) 75 mg/m2 on Day 1 plus either gemcitabine (gem) 1250 mg/m2 on Day 1 and 8 of a 21-day cycle (3-week arm) or gem 1000 mg/m2 on Day 1, 8, and 15 of a 28-day cycle (4-week arm). Patients received up to 6 cycles of treatment during this study. The primary endpoint was WHO objective response rate (ORR) and secondary endpoints included time to progression (TTP), CTC toxicity, and overall survival. Results: Of the 100 pts who were randomized to treatment, there were 51 pts in the 3-week arm: 14 females; mean age 59±8 yrs; 37% stage IIIB, 63% stage IV. In the 4-week arm, there were 49 pts: 24 females; mean age 56 ± 13 yrs; 33% stage IIIB, 67% stage IV. In the 3-week arm the overall response rate (complete response or partial response) was 24%, compared to 27% in the 4-week arm (Odds ratio: 1.17, 95% CI 0.47– 2.9, p = .819). There were no statistically significant differences between the two treatment arms in median overall survival time (3-week: 12.1 mths, 4-week: 13.8 mths; Hazard ratio (HR): 1.19, 95% CI 0.68–2.1, p = .54) and TTP (3-week: 4.9 mths, 4-week: 6.9 mths; HR: 1.33, 95% CI 0.85–2.1, p = .21). The difference in grade 3/4 hematological toxicities did not reach statistical significance (3-week: 37%, 4-week: 57%, p = .07), while grade 3/4 non-hematological toxicities were statistically significantly reduced in the 3-week arm (33% vs. 63%, p = .005). Grade 3/4 study drug related neutropenia (3-week: 27%, 4-week: 51%, p = .02) and thrombocytopenia (3-week: 8%, 4-week: 31%, p = .005) were reduced in the 3-week arm. Conclusions: While all efficacy endpoints were numerically superior in the 4-week arm, the difference was not statistically significant. However, grade 3/4 toxicities were reduced in the 3-week arm.

[Table: see text]

Risk of severe radiation pneumonitis in gemcitabine (GEM) based consolidation chemotherapy after concurrent chemo-radiation (C-RT) in stage III non-small-cell lung cancer (NSCLC)

17079

Background: Recent phase II study (S9504) showed that 3 cycles of consolidation docetaxel after C-RT is associated with prolonged survival but 6 pts (7%) had severe (≥gr 3) radiation pneumonitis and 2 (2.4%) died.(None at S9019) LCRG, a multinational Asian study group, designed a randomized phase II study aiming to assess the treatment outcomes of consolidation GEM or GEM/Carboplatin (CAR) after C-RT. GEM is a potent radiation sensitizer with known recall phenomena, thus we evaluated the risk of severe radiation pneumonitis with GEM-based consolidation chemotherapy after C-RT in this interim report. Methods: Enrollment criteria: Histologic proven NSCLC; attained CR/PR/SD after C-RT (Cisplatin-based chemotherapy between 25 mg/m2 and 40 mg/m2 per week or 60 mg/m2 to 100mg/m2 every 3 to 4 weeks; fraction dose not more than 2.0 Gy; total dose not less than 54 Gy and not higher than 64 Gy); ECOG PS 0–1; adequate hematologic/renal/liver function. Patients were screened for eligibility within 6 weeks after C-RT. Eligible patients are randomized to receive GEM 1250mg/m2 day 1,8 q21days with or without CAR 5XAUC day 1. Results: Between 3/04 and 9/05 we screened 51 patients and excluded 19. Six (31.5%) were excluded due to radiation pneumonitis.(gr 1=5 and gr 3 = 1). C-RT induced toxicity was the main reason for difficulty with accrual to this trial. We enrolled 32 patients (m:f 29:3; mean age 58 (40–78); adeno:scc:other 14:16:2; IIIa:IIIb 4:28) Median RT fraction and dose was 30 (27–32) and 60 Gy (54–64), respectively. 19 pts received GEM and 13 received GEM/CAR. Severe (≥gr 3) radiation pneumonitis was reported in 3 pts (9.3%) and 1 (3.1%) died from the complication. Another 10 and 6 pts had grade 1 and 2 radiation pneumonitis, respectively, but without significant clinical compromise. Conclusions: Radiation pneumonitis is common after C-RT with or without consolidation chemotherapy. However, severe radiation pneumonitis is relatively uncommon in pts who received GEM based consolidation chemotherapy after C-RT. A possible explanation is that we have screened out the high risk pts prior to enrollment.

[Table: see text]

Cationic peptide of the male reproductive tract, HE2α, displays antimicrobial activity against Neisseria gonorrhoeae, Staphylococcus aureus and Enterococcus faecalis

OBJECTIVES

To analyse the in vitro antimicrobial effects of synthetic HE2alpha peptide against Neisseria gonorrhoeae, Staphylococcus aureus and Enterococcus faecalis.

METHODS

The HE2alpha peptide was synthesized based on the C-terminal sequence of the HE2alpha protein. The bacterial strains tested included two antibiotic-susceptible strains of N. gonorrhoeae and four antibiotic-resistant clinical isolates, as well as S. aureus ATCC 29213 and E. faecalis ATCC 29212. Susceptibility determinations were carried out either in 0.7% casamino acids for N. gonorrhoeae isolates or in 10 mM phosphate buffer for S. aureus and E. faecalis strains. Antibacterial effects were measured in a dose- and time-dependent manner. After exposure to the peptide in solution, the number of viable cells was determined by counting colony forming units (cfu).

RESULTS

The HE2alpha peptide exhibited time- and dose-dependent antibacterial effects on all N. gonorrhoeae isolates tested. S. aureus and E. faecalis strains were also susceptible to the peptide. All strains tested were susceptible to the peptide at high concentrations (50 or 100 mg/L) and some strains were susceptible to a peptide concentration of 25 mg/L.

CONCLUSIONS

The peptide HE2alpha, which is derived from the male urogenital tract, exhibits antibacterial activity against both gram-positive and gram-negative pathogens in vitro. The peptide is active against both antibiotic-susceptible and -resistant N. gonorrhoeae isolates. Further investigation of the antimicrobial properties of the peptide is warranted.

Identification and characterization of cross-reactive antigens from Neospora caninum and Toxoplasma gondii

Murine monoclonal antibodies (mAbs) against Neospora caninum tachyzoites were produced to identify the cross-reactive antigens between N. caninum and Toxoplasma gondii. Ten mAbs recognizing cross-reactive antigens of both parasites were obtained and tentatively classified into 6 different groups based on their reactivity patterns in an indirect fluorescent antibody test and Western blot analysis. Three mAbs in group 1 recognized antigens located on the surface of parasites with molecular masses ranging from 28 to 76 kDa; one mAb in group 2 recognized antigens located on interior organelles of parasites with a molecular mass of 50 kDa; one mAb in group 3 recognized antigens located on interior organelles of parasites with molecular masses of 35 kDa and 14 kDa; three mAbs in group 4 recognized antigens located on interior organelles with a molecular mass of 64 kDa; one mAb in group 5 recognized antigens located on the surface of parasites with an unknown molecular mass; one mAb in group 6 recognized antigens located on the apical end of parasites with an unknown molecular mass. The mAbs in groups 1, 2, 3, and 5 showed inhibitory effects on the growth of the two parasites in vitro in a dose-dependent manner. A cDNA expression library prepared from N. caninum tachyzoite mRNA was immunoscreened with the mAb panel. Three kinds of proteins, protein disulfide isomerase (PDI), heat-shock protein 70 (HSP70), and ribosomal protein 1 (RP1), were identified as cross-reactive antigens recognized by mAbs in groups 2, 3, and 4, respectively. Some of the proteins could be useful in developing vaccines or drugs for controlling the diseases caused by the two parasites.

Genetic characterization of H5N1 avian influenza viruses isolated in southern China during the 2003–04 avian influenza outbreaks

The recent H5N1 avian influenza outbreaks in Asia spread over more than 8 countries. It has caused enormous economic loss and grand challenges for the public health. During these breakouts we isolated three strains of H5N1 Avian Influenza Virus (AIV) from chickens and one from duck in different farms of Southern China. We completely sequenced these four AIVs. Molecular characterization demonstrated that these strains retain the reported H5N1 AIV sequence properties relevant to virus virulence and host adaptation. Phylogeny results demonstrated that three of these isolates (except A/Chicken/Guangdong/174/04) were closely linked to other H5N1 AIVs isolated from the recent H5N1 outbreaks in Asia. Six of 8 segments (except PA and M) of A/Chicken/Guangdong/174/04 also shares a close linkage to other H5N1 AIVs isolated from the recent H5N1 outbreaks. However, the PA gene of A/Chicken/Guangdong/174/04 and another H5N1 strain forms a distinct subgroup along with an H6N1 AIV, and the M gene of A/Chicken/Guangdong/174/04 shows a close linkage to some H5N1 AIVs from aquatic species in China. Our findings suggest that a new genotype of AIV (in addition to previous reported ones) was present during the 2003-04 Asian bird flu outbreaks and that continuing virus surveillance of AIVs be conducted to monitor the evolutionary paths of the A/Chicken/Guangdong/174/04-like AIVs.

Sequence of HA gene of avian influenza A/Chicken/Guangdong/SS/1994 (H9N2) virus

The RNA of the hemagglutinin (HA) gene of A/Chicken/Guangdong/SS/1994 (H9N2) was reverse transcription-polymerase chain reaction amplified, and the cDNA was cloned into a plasmid vector. The complete coding sequence of the HA gene was sequenced and included 1683 nucleotides, which encoded for a protein of 560 amino acids. The potential glycosylation sites related to HA protein function were highly conserved. The amino acid sequence of the HA proteolytic cleavage was G-S-S-R/G. This cleavage site sequence is compatible with a low-pathogenic avian influenza virus. Sequence comparison of this HA gene with other H9 influenza virus sequences in the GenBank database showed a 82%-97% nucleotide and amino acid sequence similarity.

A multicenter phase II study of the efficacy and safety of docetaxel plus cisplatin in Asian chemonaïve patients with metastatic or locally advanced non-small cell lung cancer

AIMS

To evaluate the efficacy and safety of docetaxel-cisplatin in patients with metastatic or locally advanced non-small cell lung cancer (NSCLC).

METHODS

Chemotherapy-naïve patients with histologically confirmed TNM stage III or IV NSCLC were recruited from 12 Asian trial centers. Patients received docetaxel (75 mg/m2) and cisplatin (75 mg/m2) every 3 weeks for 6 cycles.

RESULTS

130 of 146 patients were evaluable for efficacy (60% stage IV). Three complete and 58 partial responses were observed (overall response rate: 46.9%; 95% CI: 38.3-55.5%). Median time to progression was 6.9 months and median survival was 14.0 months; 1-year survival was 59.5%. Grade 3/4 neutropenia, thrombocytopenia and anemia occurred in 69.2%, 6.2% and 18.5% of patients, respectively. Grade 3/4 vomiting was observed in 13.7% and grade 3/4 neurosensory effects were observed in 2.7% of patients. There was one case of treatment-related death due to sepsis.

CONCLUSION

Docetaxel-cisplatin is an effective and well-tolerated treatment in Asian patients with NSCLC.

[Assay of sensitivity of Plasmodium falciparum to chloroquine, amodiaquine, piperaquine, mefloquine and quinine in Yunnan province]

AIM

To determine the sensitivity of P. falciparum to chloroquine, amodiaquine, piperaquine, mefloquine and quinine in Yunnan Province of China in 1992-1995.

METHODS

Rieckmann's in vitro microtechnigue was used. The sensitivity of P. falciparum was tested to the above-mentioned antimalarials.

RESULTS

The resistance rates of isolates of P. falciparum from the south, southeast and the west part of Yunnan to chloroquine and amodiaquine were 96.7% (29/30), 78.9% (30/38), 95.7% (22/23) and 100% (30/30), 85.3% (29/34), 8/9, respectively, with their corresponding ID50 of 125 nmol/L, 136 nmol/L and 176 nmol/L, and 52 nmol/L, 64 nmol/L and 72 nmol/L, respectively. All the isolates were sensitive to quinine and their ID50 were 480 nmol/L, 352 nmol/L, 608 nmol/L, respectively. The resistance rates of P. falciparum from the south part and southeast part of Yunnan to piperaquine were 96.4% (27/29), 72.9 (27/37), respectively, their ID50 were 320 nmol/L and 228 nmol/L; all the cases were sensitive to mefloqine, their ID50 were 68 nmol/L and 88 nmol/L.

CONCLUSION

P. falciparum generally produces resistance to chloroquine, amodiaquine and piperaquine in Yunnan Province; the degree of resistance to chloroquine of P. falciparum from the west part of Yunnan were higher than the P. falciparum from the southeast part of Yunnan; all the isolates were sensitive to mefloquine and quinine in this region.