Tislelizumab, a novel PD-1 monoclonal antibody in urothelial cancer: A real-world study

OBJECTIVE

Tislelizumab, a monoclonal antibody against programed death protein-1 (PD-1), has shown encouraging antitumor activity in urothelial cancer. This study was designed to assess the efficacy and safety of tislelizumab in urotelial cancer in a real-world setting.

METHODS

The study was a real-world retrospective study undertaken at Liaoning Cancer Hospital & Institute, China. Eligible patients were ≥18 years. Patients received 200-mg tislelizumab monotherapy intravenously every 3 weeks until the disease progressed to intolerable toxicity. Outcomes included an objective response rate (ORR), disease control rate (DCR), progression-free survival (PFS), overall survival (OS) and safety.

RESULTS

Between March 2020 and December 2022, 33 patients were enrolled. The median follow-up was 10.17 (IQR 5.73-12.47) months. Of all 33 patients, ORR and DCR were 30.30% (95% CI 15.6%-48.7%) and 42.42% (95% CI 25.48%-60.78%), respectively. The median PFS was 5.73 (95% CI 3.27-13.00) months, with a 12-month PFS rate of 31.90% (95% CI 19.20%-53.00%). The median OS was 17.7 (95% CI 12.80-not reach) months, with a 12-month OS rate of 67.50% (95% CI 52.70%-86.40%). Eleven (33.33%) and 8 (24.24%) experienced ≥grade 3 treatment-related adverse events (TRAEs) and immune-related Aes, respectively. No treatment-related deaths occurred.

CONCLUSION

The excellent efficacy and controllable safety of tislelizumab in locally advanced or metastatic urothelial cancer suggest that it may be a promising therapeutic option for this population.

LncRNA AOC4P affects biological behavior of gastric cancer cells through MAPK signaling pathway

OBJECTIVE

Long non-coding RNA (lncRNA) is closely related to the occurrence and development of gastric cancer, but the mechanism and clinical significance of lncRNA AOC4P are still unclear. This study aimed to investigate the expression and function of lncRNA AOC4P in gastric cancer.

PATIENTS AND METHODS

Quantitative Real Time-Polymerase Chain Reaction (qRT-PCR) was used to detect the expression of lncRNA AOC4P in 80 gastric cancer tissues and adjacent normal tissues. MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide), flow cytometry and transwell assays were used to study the effects of lncRNA AOC4P on the proliferation, apoptosis, migration and invasion of gastric cancer cells. Western blot was used to detect the related protein level of the mitogen-activated protein kinase (MAPK) signal pathway.

RESULTS

The expression of lncRNA AOC4P in gastric cancer tissues was higher than that in adjacent tissues. OS or DFS time were significantly shortened in patients with gastric cancer with high expression of lncRNA AOC4P. Inhibition of lncRNA AOC4P expression can inhibit cell proliferation, migration and invasion, promoting cell apoptosis to some extent. Inhibition of lncRNA AOC4P expression also can result in the decreased expression levels of extracellular-signal-regulated kinase 1 (ERK1), c-Jun N-terminal kinases (JNK) and p38 proteins.

CONCLUSIONS

High expression of lncRNA AOC4P in gastric cancer may be related to the occurrence, development and prognosis of gastric cancer. LncRNA AOC4P is expected to become a new diagnostic marker and therapeutic target for gastric cancer.

LncRNA CASC19 promotes the proliferation, migration and invasion of non-small cell lung carcinoma via regulating miRNA-130b-3p

OBJECTIVE

To uncover the biological role of long non-coding RNA (lncRNA) CASC19 in the pathogenesis of non-small cell lung carcinoma (NSCLC) and the potential mechanism.

PATIENTS AND METHODS

Expression pattern of lncRNA CASC19 in NSCLC tissues and cell lines was determined by quantitative Real Time-Polymerase Chain Reaction (qRT-PCR). Survival analysis on the correlation between CASC19 level and prognosis of NSCLC patients was conducted by introducing for the Kaplan-Meier estimator. After the transfection of si-CASC19 in A549 and PC9 cells, changes in viability, migratory, and invasive capacities were evaluated. Dual-luciferase reporter gene assay was performed to explore the interaction between microRNA-130b-3p (miRNA-130b-3p) and CASC19/ZEB2. Their interactive effects on the progression of NSCLC were finally investigated through rescue experiments.

RESULTS

LncRNA CASC19 was upregulated in NSCLC tissues and cell lines. NSCLC patients with high expression of CASC19 presented a worse survival. Knockdown of CASC19 attenuated proliferative, migratory, and invasive capacities of A549 and PC9 cells. CASC19 sponged miRNA-130b-3p and negatively regulated its level. ZEB2 was the direct target of miRNA-130b-3p. The knockdown of miRNA-130b-3p reversed the regulatory effects of CASC19 on A549 and PC9 cells.

CONCLUSIONS

CASC19 sponges miRNA-130b-3p to regulate ZBR2 as a ceRNA, thus accelerating the progression of NSCLC by regulating proliferative, migratory, and invasive capacities of tumor cells.

Hypomethylation of Notch1 DNA is associated with the occurrence of uveitis

Uveitis is a serious intra-ocular inflammatory disease that can lead to visual impairment even blindness worldwide. Notch signaling can regulate the differentiation of naive CD4⁺ T cells, influencing the development of uveitis. DNA methylation is closely related to the autoimmune diseases. In this study, we measured the Notch1 DNA methylation level, determined the Notch1 and related DNA methylases mRNA expression and evaluated the ratio of T helper type 17 regulatory T cell (Th17/T_reg ) in peripheral blood mononuclear cells (PBMCs) from uveitis patients and normal control subjects; we also tested the levels of relevant inflammatory cytokines in serum from the participants. Results indicated that compared with those in normal control individuals, the expression of ten-eleven translocation 2 (TET2) and Notch1 mRNA is elevated in uveitis patients, whereas the methylation level in Notch1 DNA promotor region [-842 ~ -646 base pairs (bp)] is down-regulated, and is unrelated to anatomical location. Moreover, the Th17/T_reg ratio is up-regulated in PBMCs from uveitis patients, accompanied by the elevated levels of proinflammatory cytokines [e.g. interleukin (IL)-2, IL-6, IL-17 and interferon (IFN)-γ] in serum from uveitis patients. These findings suggest that the over-expression of TET2 DNA demethylase may lead to hypomethylation of Notch1, activate the Notch1 signaling, induce naive CD4⁺ T cells to differentiate theTh17 subset and thus disturb the balance of the Th17/T_reg ratio in uveitis patients. Overall, hypomethylation of Notch1 DNA is closely associated with the occurrence of uveitis. Our study preliminarily reveals the underlying mechanism for the occurrence of uveitis related to the hypomethylation of Notch1 DNA, providing a novel therapeutic strategy against uveitis in clinical practice.

[Primary study on the relationship between high-risk HPV infection and vaginal cervical microbiota]

Objective: To understand characteristics of vaginal cervical microbiota in high-risk HPV (hrHPV) infected women and to uncover the relationship between hrHPV infection and vaginal cervical microbiota. Methods: All participants were randomly selected from Peking University First Hospital from September to October of 2017, including 5 subjects of control group, 5 cases of HPV16/18 group, 5 cases of other hrHPV infected group and 3 cases of cervical squamous carcinoma group. All subjects were required to fill in a questionnaire, and cervical and vaginal discharges were separately collected for microscopic examination and new generation sequencing targeting the variable region (V3-V4) of bacterial 16S rRNA gene. Results: Vaginal microbiota analysis: (1) 6 major phylum were found in vaginal microbiota:Firmicutes, Bacteroidetes, Fusobacteria, Actinobacteria, Tenericutes and Proteobacteria. Firmicutes contributed to the majority of normal vaginal flora, Bacteroidetes and Fusobacteria increased in hrHPV infected ones, while Fusobacteria showed significant difference in cervical carcinoma group. (2) Lactobacillus occupied most of normal vaginal flora while genus like Gardnella, Prevotella, Atopobium, Megasphaera and Sneathia increased in hrHPV infected subjects, Sneathia showed significant difference in cervical carcinoma group. (3) No significant difference had been calculated in Alpha diversity of four groups (P=0.073) . Cervical microbiota analysis: (1) Microbial diversity of cervical microbiota was higher than that of vaginal microbiota. (2) Significant difference had been found in Alpha diversity of four groups (P=0.046) . (3) Proteobacteria in normal cervical flora was much more than that in vagina, and Proteobacteria increased significantly in hrHPV infected cervical discharge. (3) Chlamydia increased significantly in cervical carcinoma group. Conclusions: The diversity of cervical microbiota is higher than that of vaginal microbiota. Change in cervical microbiota is more obvious than that of vagina in hrHPV infected subjects. Fusobacteria-Sneathia and Chlamydia significantly increase in cervical carcinoma group. Proteobacteria might relate to hrHPV infection.

[A primary intestinal-derived adenocarcinoma in intestine bladder substitutes: a case report]

Intestinal primary intestine-derived adenocarcinoma of the bladder substituted by the intestine is a very rare long-term complication after complete urethral reconstruction of the bladder. The probability of its occurrence is low. However, in recent years, it has been proved to be objective, but there is rare literature about its diagnosis and treatment methods. This article describes a case of cystectomy and Studer ileal conduit in Peking University Third Hospital due to bladder cancer. After 9 years, he was discovered with a primary intestinal-derived adenocarcinoma in the bladder substitutes by the intestine. A male patient, 64 years old, with persistent abdominal pain in the lower abdomen for two weeks. There was carrion-like material in the urine, no gross hematuria, no urinary frequency, urgency, dysuria, and no abnormalities in the examination. Urinary CT showed intestinal metaplasia in the bladder. There was 5.7 cm×2.4 cm×4.8 cm irregular tissue shadow, and ureteroscopy found, on the right side, the bladder tumor whose diameter was 4-5 cm. We performed open lumpectomy and repaired the bladder, and postoperative pathology showed middle-high differentiated adenocarcinoma. The patient recovered well after the surgery. This article reviewed the similar intestinal primary intestine-derived adenocarcinoma of the bladder substituted by the intestine and found that it had the highest incidence in the elderly male population. The pathogenetic factor was most closely related to the smoking. If the patients developed hematuria, carrion-like substances in the urine, and bladder irritation, the possibility of tumor development should be suspected. Then the patients should promptly take the tests, such as urine exfoliation cytology, urine FISH, urinary system B-ultrasound, cystoscopy, etc. The microscope was the most direct observation of the lesion site examination. If the pathological tumor occurred ,and then the tumor should be immediately removed, and a new urinary diversion was needed to avoid further progress of the tumor. And postoperative smoking was strictly prohibited, also the patients should strictly control their eating habits and regularly adhere to the follow-up at least 4 years or more, but the lifelong follow-up and review was a must. The mechanism of intestinal primary intestinederived adenocarcinoma of the bladder substituted by the intestine is still unclear. Studies suggest that it may be related to N-nitroso compounds, smoking, and postoperative inflammatory reactions.

[A phase Ⅲ multi-center clinical trial on safety and efficacy of a domestic plasma derived factor Ⅸ for the treatment of patients with hemophilia B]

Objective: To evaluate the efficacy and safety of a domestic human plasma derived coagulation Factor Ⅸ concentrate (pd-FⅨ) in patients with hemophilia B. Methods: The study was a multicenter, open-label and single-arm study. The efficacy of pd-F Ⅸ was evaluated by objective performance criteria. The doses of pd-FⅨ were calculated according to the bleeding symptom and disease severity. The infusion efficiency of pd-FⅨ and improvement of bleeding symptoms were measured at 30 minutes and (24±4) h after the first infusion, respectively. Adverse events were recorded. Viral infection and FⅨ inhibitor were detected 90 d after the first infusion. Results: All 36 subjects with hemophilia B were enrolled in the study. The median age of these patients was 31 years old and the median injection doses were 4 (1-17) times. The hemostatic effect of 27/36 (75.00%) and 9/36 (25.00%) acute bleeding events were rated as "excellent" and "better" , respectively. The recovery rate was 111.92% (65.55%-194.28%) at 30 minutes after infusion of FⅨ. There was no adverse event related to FⅨ. No reactivation of HBV, HCV or HIV and FⅨ inhibitor was detected at 90-104 d after the first FⅨ infusion. Conclusion: This domestically made human plasma derived FⅨ concentrate is safe and effective in the treatment of acute bleeding in patients with hemophilia B. Clinical trial registration: China food and Durg Administration, 2016L08027.

[Multiple endoscopy for the treatment of upper urinary tract calculi following ileal conduit: a case report and literature review]

Upper urinary tract calculi with infection is a quite difficult acute urologic emergency. And what is more, upper urinary tract obstruction after radical cystectomy following urinary diversion may be fatal in the vulnerable patients with this kind of situation. Postoperative anatomy and other factors affect the upper urinary tract calculi, and urinary tract infection greatly increased the risk. But it is particularly difficult to handle with patients with poor general condition and septic shock treatment, so how to optimize the selection program is worth further studying. A 65-year-old man was admitted to hospital for combining with renal and ureteral calculi after radical cystectomy (Bricker) in March 2017. The patient underwent transurethral resection of bladder tumor in the outer court because of the discovery of bladder tumor one year before, The postoperative pathology was high-grade papillary urothelial carcinoma and he underwent regular irrigation of the bladder. Because of tumor recurrence, he came to Peking University Third Hospital for further treatment in August 2016, and the examination of urinary tract CT indicated bladder cancer; for bilateral multiple renal pelvis and renal calices calculi, he was given laparoscopic radical cystectomy. After four months, due to sudden chill fever, he was hospitalized. After definite diagnosis, anti-inflammatory treatment combined with left nephrostomy was given. The two-stage lithotripsy was performed. After expansion of the original left renal fistula to 24 F(1 F=0.33 mm), 24 F sheath was inducted into the kidney. We introduced a flexible ureteroscopy into the channel down to the ureteral obstruction, where we found a 1 cm oval black brown stone obstructed. A guide wire was inducted through the stones down to ileal conduit in the right lower quadrant. Through the ureteroscopy, we made ureteral calculi broken into powder, and replaced the residual stones into the renal pelvis. Then we used the nephroscopy for lithotropsy in the pelvis, and finally we introduced a flexible cystoscopy for the residual stone. The operation was successful, the operation time was 181 min, and intraoperative bleeding was 10 mL. After operation, no residual stones were found in kidney, ureter, bladder (KUB) plain films. No operation complications were related to the urinary tract. Therefore, multiple endoscopy with combination therapy of upper urinary tract calculi following urinary diversion is safe and effective, and the reasonable choice with the advantages of each instrument can improve the stone clearance rate and shorten the operation time. This can be used as a useful complement to traditional treatment.

The influence of connective tissue growth factor on rabbit ligament injury repair

Objectives

The injured anterior cruciate ligament (ACL) is thought to exhibit an impaired healing response, and attempts at surgical repair have not been successful. Connective tissue growth factor (CTGF) is reported to be associated with wound healing, probably through transforming growth factor beta 1 (TGF-β1).

Methods

A rabbit ACL injury model was used to study the effect of CTGF on ligament recovery. Quantitative real-time PCR (qRT-PCR) was performed for detection of changes in RNA levels of TGF-β1, type 1 collagen (COL1), type 2 collagen (COL2), SRY-related high mobility group-box gene9 (SOX9), tissue inhibitor of metalloproteinase-1 (TIMP-1) and matrix metallopeptidase 13 (MMP-13). Expression of related proteins was detected by Western blotting.

Results

The current study showed that CTGF could promote the recovery of an injured anterior cruciate ligament. It can upregulate mRNA and expression of TGF-β1, COL1, COL2, SOX9, and tissue inhibitor of TIMP-1, and downregulate mRNA and expression of MMP-13, suggesting that the curative effect of CTGF on injured rabbit ligaments is through regulation of these cellular factors.

Conclusions

This finding revealed the healing role of CTGF in injured tissues and provides new possibilities of treating injured tissues and wound healing by using CTGF.

Cite this article: X. Sun, W. Liu, G. Cheng, X. Qu, H. Bi, Z. Cao, Q. Yu. The influence of connective tissue growth factor on rabbit ligament injury repair. Bone Joint Res 2017;6:399–404. DOI: 10.1302/2046-3758.67.BJR.2016-0255.R1.

[Surgery for renal carcinoma with supradiaphragmatic tumor thrombus: avoiding sternotomy and cardiopulmonary bypass]

OBJECTIVE

To describe a feasible surgical technique for patients with renal cell carcinoma associated with a supradiaphragmatic tumor thrombus that avoids cardiopulmonary bypass procedure.

METHODS

We retrospectively analyzed 2 cases with right kidney tumor and tumor thrombus above the diaphragm treated in April and August, 2015. The two patients were both female, aged 73 and 67 years. The tumor sizes of right kidneys were 7.0 cm×6.3 cm×5.7 cm and 8.7 cm×7.0 cm×5.2 cm, and the tumor thrombuses were 1.3 cm and 1.8 cm above the diaphragm. The second patient had synchronous metastasis in right adrenal gland , and the tumor thrombus arose from the adrenal vein but not the renal vein. Intraoperative transesophageal echocardiography (TEE) was used to assess real-time mobility of the thrombus. A modified chevron incision was used, the right kidney was mobilized laterally and posteriorly, and the renal artery was identified, ligated, and divided. The infradiaphragmatic inferior vena cava (IVC) was exposed and isolated by mobilizing the liver off the diaphragm or to the left (piggyback liver mobilization, case 2). The central diaphragm tendon was dissected or incised in the midline until the supradiaphragmatic intrapericardial IVC was identified and gently pulled beneath the diaphragm and into the abdomen. The tumor thrombus was then "milked" downward out of the intrapericardial IVC under the guidance of TEE. The distal and proximal IVC to the tumor thrombus, porta hepatis, and left renal vein were clamped. Tumor thrombus was removed from the IVC. The IVC was sutured and vascular clamps were placed below the major hepatic veins. Pringle's maneuver was then released and hepatic blood drainage was permitted during closure of the remaining IVC. Related literature was reviewed.

RESULTS

Complete resection was successful through the transabdominal approach without CBP in both patients. Estimated blood loss was 1 500 mL and 2 000 mL, and 1 200 mL and 800 mL of blood were transfused. The postoperative courses were uneventful. Both patients subsequently underwent tyrosine-kinase inhibitor therapy. Both patients were alive without tumor recurrence or new metastasis during the follow-up of 6 months and 9 months.

CONCLUSION

In selected cases, renal cell carcinoma extending into the IVC above the diaphragm can be resected without sternotomy, CBP or DHCA.

Transmission blocking potency and immunogenicity of a plant-produced Pvs25-based subunit vaccine against Plasmodium vivax

Malaria transmission blocking (TB) vaccines (TBVs) directed against proteins expressed on the sexual stages of Plasmodium parasites are a potentially effective means to reduce transmission. Antibodies induced by TBVs block parasite development in the mosquito, and thus inhibit transmission to further human hosts. The ookinete surface protein P25 is a primary target for TBV development. Recently, transient expression in plants using hybrid viral vectors has demonstrated potential as a strategy for cost-effective and scalable production of recombinant vaccines. Using a plant virus-based expression system, we produced recombinant P25 protein of Plasmodium vivax (Pvs25) in Nicotiana benthamiana fused to a modified lichenase carrier protein. This candidate vaccine, Pvs25-FhCMB, was purified, characterized and evaluated for immunogenicity and efficacy using multiple adjuvants in a transgenic rodent model. An in vivo TB effect of up to a 65% reduction in intensity and 54% reduction in prevalence was observed using Abisco-100 adjuvant. The ability of this immunogen to induce a TB response was additionally combined with heterologous prime-boost vaccination with viral vectors expressing Pvs25. Significant blockade was observed when combining both platforms, achieving a 74% and 68% reduction in intensity and prevalence, respectively. This observation was confirmed by direct membrane feeding on field P. vivax samples, resulting in reductions in intensity/prevalence of 85.3% and 25.5%. These data demonstrate the potential of this vaccine candidate and support the feasibility of expressing Plasmodium antigens in a plant-based system for the production of TBVs, while demonstrating the potential advantages of combining multiple vaccine delivery systems to maximize efficacy.

[Surgery for renal carcinoma with supradiaphragmatic tumor thrombus: avoiding sternotomy and cardiopulmonary bypass]

OBJECTIVE

To describe a feasible surgical technique for patients with renal cell carcinoma associated with a supradiaphragmatic tumor thrombus that avoids cardiopulmonary bypass procedure.

METHODS

We retrospectively analyzed 2 cases with right kidney tumor and tumor thrombus above the diaphragm treated in April and August, 2015. The two patients were both female, aged 73 and 67 years. The tumor sizes of right kidneys were 7.0 cm×6.3 cm×5.7 cm and 8.7 cm×7.0 cm×5.2 cm, and the tumor thrombuses were 1.3 cm and 1.8 cm above the diaphragm. The second patient had synchronous metastasis in right adrenal gland , and the tumor thrombus arose from the adrenal vein but not the renal vein. Intraoperative transesophageal echocardiography (TEE) was used to assess real-time mobility of the thrombus. A modified chevron incision was used, the right kidney was mobilized laterally and posteriorly, and the renal artery was identified, ligated, and divided. The infradiaphragmatic inferior vena cava (IVC) was exposed and isolated by mobilizing the liver off the diaphragm or to the left (piggyback liver mobilization, case 2). The central diaphragm tendon was dissected or incised in the midline until the supradiaphragmatic intrapericardial IVC was identified and gently pulled beneath the diaphragm and into the abdomen. The tumor thrombus was then "milked" downward out of the intrapericardial IVC under the guidance of TEE. The distal and proximal IVC to the tumor thrombus, porta hepatis, and left renal vein were clamped. Tumor thrombus was removed from the IVC. The IVC was sutured and vascular clamps were placed below the major hepatic veins. Pringle's maneuver was then released and hepatic blood drainage was permitted during closure of the remaining IVC. Related literature was reviewed.

RESULTS

Complete resection was successful through the transabdominal approach without CBP in both patients. Estimated blood loss was 1 500 mL and 2 000 mL, and 1 200 mL and 800 mL of blood were transfused. The postoperative courses were uneventful. Both patients subsequently underwent tyrosine-kinase inhibitor therapy. Both patients were alive without tumor recurrence or new metastasis during the follow-up of 6 months and 9 months.

CONCLUSION

In selected cases, renal cell carcinoma extending into the IVC above the diaphragm can be resected without sternotomy, CBP or DHCA.

Prognostic Importance of Circulating Tumor Cells in Nonsmall Cell Lung Cancer: A Prospective Study

Purpose: To investigate the prognostic value of circulating tumor cells (CTCs) and to predict the treatment response in a non-small cell lung cancer (NSCLC).Methodology: A single-center prospective study involving 93 patients with NSCLC was conducted. Blood samples were analyzed for CTC count before and after chemotherapy. Clinical relevance of CTCs with patient`s characteristics and treatment response were determined.Results: Higher levels of CTCs were associated with severe stage of NSCLC (p = 0.003), tumor histology (p = 0.014) and metastases (p = 0.013). Significant difference in CTC count was observed in favorable (CTCs < 5) and unfavorable (CTCs ≥ 5) groups. Progression-free survival (PFS) was 5.8 months (range: 5.32 to 6.43) and 2.2 months (range: 1.85 to 3.01) in the favorable and unfavorable groups, respectively (HR: 3.88, 95% CI, p < 0.001). Similarly, overall survival (OS) was 7.3 months (95% CI, 6.51 to 7.92) and 3.9 months (95% CI, 1.99 to 5.13), respectively (HR: 4.8, 95% CI, p < 0.001). Multivariate  regression analysis revealed CTCs as strong predictors of OS and PFS. Significant reduction (p < 0.001) in CTC count was also observed after one cycle of chemotherapy.Conclusion: Patients with low CTC count live longer and remain progression-free for a longer period of time than those with high CTC count. High CTCs can be detected in severe forms of lung cancer and can be used as a valid prognostic marker. However, this assertion requires validation in larger prospective clinical cohorts.Keywords: Circulating tumor cells, Non-small cell lung cancer, Circulating tumor cell, Prognosis

DEC1 regulates breast cancer cell proliferation by stabilizing cyclin E protein and delays the progression of cell cycle S phase

Breast cancer that is accompanied by a high level of cyclin E expression usually exhibits poor prognosis and clinical outcome. Several factors are known to regulate the level of cyclin E during the cell cycle progression. The transcription factor DEC1 (also known as STRA13 and SHARP2) plays an important role in cell proliferation and apoptosis. Nevertheless, the mechanism of its role in cell proliferation is poorly understood. In this study, using the breast cancer cell lines MCF-7 and T47D, we showed that DEC1 could inhibit the cell cycle progression of breast cancer cells independently of its transcriptional activity. The cell cycle-dependent timing of DEC1 overexpression could affect the progression of the cell cycle through regulating the level of cyclin E protein. DEC1 stabilized cyclin E at the protein level by interacting with cyclin E. Overexpression of DEC1 repressed the interaction between cyclin E and its E3 ligase Fbw7α, consequently reducing the level of polyunbiquitinated cyclin E and increased the accumulation of non-ubiquitinated cyclin E. Furthermore, DEC1 also promoted the nuclear accumulation of Cdk2 and the formation of cyclin E/Cdk2 complex, as well as upregulating the activity of the cyclin E/Cdk2 complex, which inhibited the subsequent association of cyclin A with Cdk2. This had the effect of prolonging the S phase and suppressing the growth of breast cancers in a mouse xenograft model. These events probably constitute the essential steps in DEC1-regulated cell proliferation, thus opening up the possibility of a protein-based molecular strategy for eliminating cancer cells that manifest a high-level expression of cyclin E.

Transgenic characterization of two testis-specific promoters in the silkworm, Bombyx mori

Sex-specific regulatory elements are key components for developing insect genetic sexing systems. The current insect genetic sexing system mainly uses a female-specific modification system whereas little success was reported on male-specific genetic modification. In the silkworm Bombyx mori, a lepidopteran model insect with economic importance, a transgene-based, female-specific lethality system has been established based on sex-specific alternative splicing factors and a female-specific promoter BmVgp (vitellogenin promoter) has been identified. However, no male-specific regulatory elements have yet been identified. Here we report the transgenic identification of two promoters that drive reporter gene expression in a testis-specific manner in B. mori. Putative promoter sequences from the B. mori Radial spoke head 1 gene (BmR1) and beta-tubulin 4 gene (Bmβ4) were introduced using piggybac-based germline transformation. In transgenic silkworms, expression of the reporter gene enhanced green fluorescent protein (EGFP) directed by either BmR1 promoter (BmR1p) or Bmβ4p showed precisely testis-specific manners from the larval to adult stage. Furthermore, EGFP expression of these two transgenic lines showed different localization in the testis, indicating that BmR1p or Bmβ4p might be used as distinct regulatory elements in directing testis-specific gene expression. Identification of these testis-specific promoters not only contributes to a better understanding of testis-specific gene function in insects, but also has potential applications in sterile insect techniques for pest management.

DACH1 inhibits SNAI1-mediated epithelial-mesenchymal transition and represses breast carcinoma metastasis

Epithelial-mesenchymal transition (EMT) has a major role in cancer progression and metastasis. However, the specific mechanism of transcriptional repression involved in this process remains largely unknown. Dachshund homologue 1 (DACH1) expression is lost in invasive breast cancer with poor prognosis, and the role of DACH1 in regulating breast cancer metastasis is poorly understood. In this study, significant correlation between the expression of DACH1 and the morphology of breast cancer cells was observed. Subsequent investigation into the relationship between DACH1 and EMT showed that overexpression of DACH1 in ZR-75-30 cells induced a shift towards epithelial morphology and cell-cell adhesion, as well as increased the expression of the epithelial marker E-cadherin and suppressed cell migration and invasion. In contrast, silencing DACH1 in MCF-7 and T47D cells disrupted the epithelial morphology and cell-cell contact, reduced the expression of E-cadherin, and induced cell migration and invasion. DACH1 also specifically interacted with SNAI1, but not SNAI2, to form a complex, which could bind to the E-box on the E-cadherin promoter in an SNAI1-dependent manner. DACH1 inhibited the transcriptional activity of SNAI1, leading to the activation of E-cadherin in breast cancer cells. Furthermore, the level of DACH1 also correlated with the extent of metastasis in a mouse model. DACH1 overexpression significantly decreased the metastasis and growth of 4T1/Luc cells in BALB/c mice. Analysis of tissue samples taken from human breast cancers showed a significant correlation between the expression of DACH1 and E-cadherin in SNAI1-positive breast cancer. Collectively, our data identified a new mechanistic pathway for the regulation of EMT and metastasis of breast cancer cells, one that is based on the regulation of E-cadherin expression by direct DACH1-SNAI1 interaction.

A novel HLA-A allele, HLA-A*02:441, identified by sequence-based typing in Chinese individuals

HLA-A*02:441 differs from HLA-A*02:01:01:01 by one nucleotide exchange at position 91(T>C) with an amino acid exchange.

Atorvastatin overcomes gefitinib resistance in KRAS mutant human non-small cell lung carcinoma cells

The exact influence of statins on gefitinib resistance in human non-small cell lung cancer (NSCLC) cells with KRAS mutation alone or KRAS/PIK3CA and KRAS/PTEN comutations remains unclear. This work found that transfection of mutant KRAS plasmids significantly suppressed the gefitinib cytotoxicity in Calu3 cells (wild-type KRAS). Gefitinib disrupted the Kras/PI3K and Kras/Raf complexes in Calu3 cells, whereas not in Calu3 KRAS mutant cells. These trends were corresponding to the expression of pAKT and pERK in gefitinib treatment. Atorvastatin (1 μM) plus gefitinib treatment inhibited proliferation, promoted cell apoptosis, and reduced the AKT activity in KRAS mutant NSCLC cells compared with gefitinib alone. Atorvastatin (5 μM) further enhanced the gefitinib cytotoxicity through concomitant inhibition of AKT and ERK activity. Atorvastatin could interrupt Kras/PI3K and Kras/Raf complexes, leading to suppression of AKT and ERK activity. Similar results were also obtained in comutant KRAS/PTEN or KRAS/PIK3CA NSCLC cells. Furthermore, mevalonate administration reversed the effects of atorvastatin on the Kras/Raf and Kras/PI3K complexes, as well as AKT and ERK activity in both A549 and Calu1 cells. The in vivo results were similar to those obtained in vitro. Therefore, mutant KRAS-mediated gefitinib insensitivity is mainly derived from failure to disrupt the Kras/Raf and Kras/PI3K complexes in KRAS mutant NSCLC cells. Atorvastatin overcomes gefitinib resistance in KRAS mutant NSCLC cells irrespective of PIK3CA and PTEN statuses through inhibition of HMG-CoA reductase-dependent disruption of the Kras/Raf and Kras/PI3K complexes.

Neuronal responses in visual area V2 (V2) of macaque monkeys with strabismic amblyopia

Amblyopia, a developmental disorder of spatial vision, is thought to result from a cascade of cortical deficits over several processing stages beginning at the primary visual cortex (V1). However, beyond V1, little is known about how cortical development limits the visual performance of amblyopic primates. We quantitatively analyzed the monocular and binocular responses of V1 and V2 neurons in a group of strabismic monkeys exhibiting varying depths of amblyopia. Unlike in V1, the relative effectiveness of the affected eye to drive V2 neurons was drastically reduced in the amblyopic monkeys. The spatial resolution and the orientation bias of V2, but not V1, neurons were subnormal for the affected eyes. Binocular suppression was robust in both cortical areas, and the magnitude of suppression in individual monkeys was correlated with the depth of their amblyopia. These results suggest that the reduced functional connections beyond V1 and the subnormal spatial filter properties of V2 neurons might have substantially limited the sensitivity of the amblyopic eyes and that interocular suppression was likely to have played a key role in the observed alterations of V2 responses and the emergence of amblyopia.

A GaAs nanowire/P3HT hybrid photovoltaic device

Hybrid solar cells with an energy conversion efficiency of 1.04% were fabricated by spin-coating poly(3-hexylthiophene) (P3HT) polymer onto vertically aligned n-type GaAs nanowire arrays synthesized by molecular beam epitaxy. Experimental parameters such as the P3HT solvent mixing ratio of chlorobenzene to dichlorobenzene and nanowire surface etching were studied with a view to improving the energy conversion efficiency.

Development of temporal response properties and contrast sensitivity of V1 and V2 neurons in macaque monkeys

The temporal contrast sensitivity of human infants is reduced compared to that of adults. It is not known which neural structures of our visual brain sets limits on the early maturation of temporal vision. In this study we investigated how individual neurons in the primary visual cortex (V1) and visual area 2 (V2) of infant monkeys respond to temporal modulation of spatially optimized grating stimuli and a range of stimulus contrasts. As early as 2 wk of age, V1 and V2 neurons exhibited band-pass temporal frequency tuning. However, the optimal temporal frequency and temporal resolution of V1 neurons were much lower in 2- and 4-wk-old infants than in 8-wk-old infants or adults. V2 neurons of 8-wk-old monkeys had significantly lower optimal temporal frequencies and resolutions than those of adults. Onset latency was longer in V1 at 2 and 4 wk of age and was slower in V2 even at 8 wk of age than in adults. Contrast threshold of V1 and V2 neurons was substantially higher in 2- and 4-wk-old infants but became adultlike by 8 wk of age. For the first 4 wk of life, responses to high-contrast stimuli saturated more readily in V2. The present results suggest that although the early development of temporal vision and contrast sensitivity may largely depend on the functional maturation of precortical structures, it is also likely to be limited by immaturities that are unique to V1 and V2.

Effects of perceptual learning on local stereopsis and neuronal responses of V1 and V2 in prism-reared monkeys

Visual performance improves with practice (perceptual learning). In this study, we sought to determine whether or not adult monkeys reared with early abnormal visual experience improve their stereoacuity by extensive psychophysical training and testing, and if so, whether alterations of neuronal responses in the primary visual cortex (V1) and/or visual area 2 (V2) are involved in such improvement. Strabismus was optically simulated in five macaque monkeys using a prism-rearing procedure between 4 and 14 wk of age. Around 2 yr of age, three of the prism-reared monkeys ("trained" monkeys) were tested for their spatial contrast sensitivity and stereoacuity. Two other prism-reared monkeys received no training or testing ("untrained" monkeys). Microelectrode experiments were conducted around 4 yr of age. All three prism-reared trained monkeys showed improvement in stereoacuity by a factor of 7 or better. However, final stereothresholds were still approximately 10-20 times worse than those in normal monkeys. In V1, disparity sensitivity was drastically reduced in both the trained and untrained prism-reared monkeys and behavioral training had no obvious effect. In V2, the disparity sensitivity in the trained monkeys was better by a factor of approximately 2.0 compared with that in the untrained monkeys. These data suggest that the observed improvement in stereoacuity of the trained prism-reared monkeys may have resulted from better retention of disparity sensitivity in V2 and/or from "learning" by upstream neurons to more efficiently attend to residual local disparity information in V1 and V2.

Cortical Effects of Brief Daily Periods of Unrestricted Vision During Early Monocular Form Deprivation

Experiencing daily brief periods of unrestricted vision during early monocular form deprivation prevents or reduces the degree of resulting amblyopia. To gain insight into the neural basis for these “protective” effects, we analyzed the monocular and binocular response properties of individual neurons in the primary visual cortex (V1) of macaque monkeys that received intermittent unrestricted vision. Microelectrode-recording experiments revealed significant decreases in the proportion of units that were dominated by the treated eyes, and the magnitude of this ocular dominance imbalance was correlated with the degree of amblyopia. The sensitivity of V1 neurons to interocular spatial phase disparity was significantly reduced in all treated monkeys compared with normal adults. With unrestricted vision, however, there was a small but significant increase in overall disparity sensitivity. Binocular suppression was prevalent in monkeys with constant form deprivation but significantly reduced by the daily periods of unrestricted vision. If neurons exhibited consistent responses to stimulation of the treated eye, monocular response properties obtained by stimulation of the two eyes were similar. These results suggest that the observed protective effects of brief periods of unrestricted vision are closely associated with the ability of V1 neurons to maintain their functional connections from the deprived eye and that interocular suppression in V1 may play an important role in regulating synaptic plasticity of these monkeys.

[Cloning and sequence analysis of the gene encoding the partial region CS protein of a Plasmodium falciparum isolate from Yunnan]

AIM

Determining nucleotide sequence of the circumsporozoite protein partial gene of the Plasmodium falciparum PFD-3/YN (Yunnan of China) and finding out the differences of the CS gene sequence between Chinese Plasmodium falciparum isolate and other isolates.

METHODS

The circumsporozoite protein gene fragment was amplified by polymerase chain reaction and cloned into M13 bacteriophage. M13-CSP single strand DNAs of the three positive clones were extracted respectively. Then, the nucleotide sequence of the CS gene fragment was determined by the dideoxy chain termination method. PCGENE software was used to compare and analyze the CS gene sequence of the six isolates.

RESULTS

Different degrees of diversity of the CS gene sequences were found among P. falciparum PFD-3/YN and other isolates(T4, Wellcome, NF54, 3D7 and 7G8). A non-silent substitution at the nucleotide level being found in the P. f Th/Tc antigenic epitope region.

CONCLUSION

There were differences in the CS gene sequence among P. falciparum PFD-3/YN and those of other isolates.

[The relationship between the mutation of methylenetetrahydrofolate reductase gene 677C-->T and the diabetic microangiopathy]

OBJECTIVE

To investigate the relationship between the mutation of methylenetetra- hydrofolate reductase gene 677C-->T and the diabetic microangiopathy(DMA) in diabetes mellitus(DM).

METHODS

A total of 168 subjects were divided into control group, DM group and DMA group(including diabetic nephropathy and diabetic retinopathy). PCR-restrictive fragment length polymorphism(RFLP) analysis was conducted to examine mutation, and then the frequency of mutation was statistically computed.

RESULTS

Markedly elevated mutation was observed in patients with diabetic nephropathy and diabetic retinopathy as compared with non-microangiopathy diabetes mellitus and normal people (20.8% vs 8.3% and 7.3%, P<0.01). The odds ratio of the TT genotype for DMA was 3.36, P<0.001.

CONCLUSION

It was found that the mutation of methylenetetrahydrofolate reductase gene 677C-->T was an impressibility factor of diabetic microangiopathy.

Assessment of a vaccinia virus vectored multi-epitope live vaccine candidate for Plasmodium falciparum

We constructed a live recombinant vaccinia virus vaccine candidate containing a synthesised hybrid gene termed 'HGFSP' encoding circumsporozoite protein (CSP), major merozoite surface antigen-1(MSA1), major merozoite surface antigen-2 (MSA2), and ring-infected erythrocyte surface antigen (RESA) of Plasmodium falciparum, interleukin-1 (IL-1) and tetanus toxin (TT) epitopes. Anti-recombinant vaccinia virus rabbit sera and IgG were tested in inhibition experiments in vitro. Results showed that the recombinant vaccinia virus had some capability to inhibit the growth of P. falciparum in vitro. The sera of rabbits, rats, and mice immunised with recombinant virus showed obvious IL-2 activity 4-6 weeks after immunisation. The interferon (IFN) level of sera from these animals 6 weeks after immunisation was significantly higher than before immunisation. These results indicate that the recombinant vaccinia virus can stimulate cell mediated responses (Th1 cell response) in immunised animals, and has the capability to inhibit multiplication of in vitro cultured P. falciparum. Thus this recombinant vaccinia virus is an appropriate vaccine candidate for further evaluation in Aotus monkey or human clinical trails.

N-Methyl-D-aspartate receptor subunit proteins and their phosphorylation status are altered selectively in Alzheimer's disease

The N-methyl-D-aspartate (NMDA) receptor is a subtype of the ionotropic glutamate receptor that plays a pivotal role in synaptic mechanisms of learning and memory. We tested the hypothesis that NMDA receptor protein levels are abnormal in Alzheimer's disease (AD). By immunoblotting, we assessed levels of both non-phosphorylated and phosphorylated receptor subunit proteins from four separate regions of 16 post-mortem brains. Three patient groups with thorough pre-mortem neuropsychological testing were evaluated, including AD, early AD (p-AD), and control patients. Protein levels and phosphorylation status of NMDA receptor subunits NR1, NR2A and NR2B were correlated with measurements of cognitive performance. Selective regional reductions in NMDA receptor subunit protein levels were found in AD compared to controls, but protein levels in the p-AD group were similar to controls. Reductions of NR1 (53%, P<0.05) and NR2B (40%, P<0.05) were identified in hippocampus. Reductions of NR2A (39%, P<0.05) and NR2B (31%, P<0.01) were found in entorhinal cortex. No reductions were noted in occipital cortex and caudate. Phosphorylated NR2A (30%, P<0.05) and NR2B (56%, P<0.01) were selectively reduced in entorhinal cortex in AD when compared to controls. Both phosphorylated and non-phosphorylated NMDA receptor protein levels in entorhinal cortex correlated with Mini-Mental Status Examination (MMSE) and Blessed (BIMC) scores. The losses of phosphorylated and non-phosphorylated NMDA receptor subunit proteins correlated with changes in synaptobrevin levels (a presynaptic protein), but not with age or post-mortem interval. Our results demonstrate that NMDA receptor subunits are selectively and differentially reduced in areas of AD brain, and these abnormalities correlate with presynaptic alterations and cognitive deficits in AD.

Mixed-mechanism ionization to enhance sensitivity in atmospheric pressure ionization LC/MS

A novel dual-mechanism ionization technique for LC/MS/MS has been observed, characterized and applied to the quantitation of a tertiary amine-containing drug compound in dog plasma. This mixed-mechanism ionization approach can improve the sensitivity of the pneumatically assisted electrospray experiment. Under conditions of higher than normal chromatographic flow and lower electrospray voltage, approximately a 4-fold increase in sensitivity was realized. A detection limit of 16 pg (45 fmol) on-column, and inter-day imprecision and inaccuracy of < 11 and < 15%, respectively, were obtained. A trade-off in concentration sensitivity in favor of ease of sample preparation was made to increase sample throughput. Although results strongly suggest that mixed-mechanism ionization is in operation, and that pneumatically assisted electrospray is a partial contributor to the overall ionization process, the exact nature of the second mechanism of ionization is unclear at this time.

Selective regional loss of exocytotic presynaptic vesicle proteins in Alzheimer's disease brains

We tested whether regional or selective alterations in presynaptic proteins occur in Alzheimer's disease (AD) and correlate with tests of cognitive function. We measured the levels of seven presynaptic proteins (synaptobrevin, synaptotagmin, SNAP-25, syntaxin, SV2, Rab3a, and synapsin I) by immunoblotting in postmortem tissue from four brain regions (hippocampus, entorhinal cortex, caudate nucleus, and occipital cortex). Three subject groups were studied: AD, possible/early AD (p-AD), and age-matched controls. Synaptobrevin and synaptotagmin were significantly reduced (29%, P<0.08; 38%, P<0. 07) in hippocampus in p-AD compared to controls. In definite AD compared to controls, selective regional reductions in vesicle proteins were found: synaptobrevin (46%, P<0.05), synaptotagmin (52%, P<0.01), and Rab3a (30%, P<0.05) in hippocampus; synaptobrevin (31%, P<0.01), synaptotagmin (15%, P<0.05), and Rab3a (44%, P<0.05) in entorhinal cortex. In contrast, the levels of two vesicle proteins (synapsin I and SV2) and two presynaptic membrane proteins (syntaxin and SNAP-25) were similar to controls. Synaptobrevin was the only vesicle protein reduced in AD in all four brain regions (occipital cortex 37%, P<0.05; caudate nucleus 31%, P<0.05). By univariate analysis of all cases, Mini-Mental State Examination, Blessed (BIMC) and Free Recall scores were strongly correlated with reduced levels of synaptic vesicle proteins synaptobrevin, synaptotagmin, and Rab3a in hippocampus and entorhinal cortex. These results suggest that there are selective and early defects in presynaptic vesicle proteins, but not synaptic plasma membrane proteins in AD and that defects correlate with cognitive dysfunction in this disease.

Quantification and rapid metabolite identification in drug discovery using API time-of-flight LC/MS

Liquid chromatography/mass spectrometry (LC/MS), utilizing a time-of-flight (TOF) mass analyzer, has been evaluated and applied to problems in bioanalysis for pharmacokinetics and drug metabolism. The data obtained by TOF MS differ from those obtained using quadrupole mass spectrometer instruments in that full-scan spectra can be routinely collected with greater sensitivity and speed. Both quantitative and qualitative information, including compound concentration in rat plasma and full-scan atmospheric pressure ionization mass spectra, are concurrently obtained. This approach has been used to characterize the disposition of several drug compounds that have been simultaneously dosed to rats in a cassette format. Quantitation limits in the 5-25 ng/mL range (approximately 20 nM) were obtained from nominal mass chromatograms (0.5 Da resolution). A reference lock mass was used to provide accurate mass measurement to reach third decimal place accuracy in the monoisotopic molecular weight. An improvement in quantitation limits was demonstrated after using accurate mass determinations. Several possible preliminary drug metabolites were confirmed or refuted, based on accurate mass. The trend of metabolite formation and clearance was qualitatively evaluated.

[A clinical observation of krypton yellow laser photocoagulation for cystoid macular edema in nonproliferative diabetic retinopathy]

OBJECTIVE

To evaluate the clinical effects of krypton yellow laser photocoagulation for cystoid macular edema (CME) in nonproliferative diabetic retinopathy (NPDR).

METHODS

52 eyes (37 cases) with CME in NPDR were treated with local or grid macular krypton yellow photocoagulation, and according to the course they were divided into two groups: group I (<or= 6 months) and group II (>or= 7 months). The follow-up was 1 year. The visual acuity and the degree of macular edema in various period were analyzed and compared.

RESULTS

The mean visual acuity was 0.27 +/- 0.21 before treatment and 0.53 +/- 0.26 after treatment (P < 0.01), 90.4% was increased, 5.8% was stable and 3.8% was decreased. CME disappeared completely in 55.8% of the patients, disappeared partially in 42.3% and stable in 1.9%. In group I the visual acuity was improved in 81.5% of the patients at post-treatment 1 month; at post-treatment 6 months, the visual acuity was increased in 100% of the cases, CME disappeared completely in 70.4% and disappeared partially in 29.6%. In group II, the visual acuity was improved in 20% of the patients at post-treatment 1 month, and at post-treatment 6 months in 88%, CME disappeared completely in 40% and disappeared partially in 56%. The differences in the rate of visual recovery and therapeutic effects between the two groups were statistically significant (P < 0.01).

CONCLUSIONS

Krypton yellow laser is prominently effective and selective for CME in NPDR. The effects are related to the course of the disease, and the therapeutic results are better in cases receiving early treatment.

A recombinant multi-epitope, multi-stage malaria vaccine candidate expressed in Escherichia coli

OBJECTIVE

To construct and evaluate a recombinant multi-epitope, multistage malaria vaccine candidate expressed in Escherichia coli (E. coli).

METHODS

A hybrid gene (HGF) encoding several putative immunodominant T or T/B epitopes from MSP-1, MSP-2, Pf155/RESA of Plasmodium falciparum (P. falciparum) and two immune-stimulating epitopes from interleukin-1 and tetanus toxin was synthesized. Two copies of HGF and a copy of gene encoding Pattaroyo's Spf66 were connected together to construct a sandwich hybrid gene HGFSP. The gene was cloned into an expression vector pWR450-I for production of a fusion protein with beta-galactosidase. Efficacy of this vaccine candidate in inducing specific immunity against malaria parasites was evaluated.

RESULTS

Immunization of different species of animals with purified recombinant peptide showed that the peptide was able to induce remarkable antibody response to the immunized peptide as well as falciparum malaria parasites. The epitopes included in the construct could induce antibodies against the intact parasite proteins as demonstrated by western blotting, indicating the epitopes retained their antigenicity in the new peptide construct. Antibodies from animals immunized with recombinant HGFSP peptide exhibited good ability in inhibition of the in vitro growth of malaria parasites, augmentation of phagocytosis of the parasites or infected RBC by phagocytes, and facilitation of antibody dependent cell mediated cytotoxicity to the cultured malaria parasites.

CONCLUSION

The recombinant peptide seems to be a potential candidate which is valuable for further investigation.

[Finding of new FCC1/HN antigenic expressed sequence tag(ESTs) of Plasmodium falciparum]

AIM

To sequence the strong positive clones obtained by immuno-screening of Plasmodium falciparum FCC1/HN lambda gt11 cDNA expression library, and to elucidate the antigenic expressed sequence tags through sequencing the cDNA insert of these positive clones, and new antigenic ESTs could serve as a resource to pursue their corresponding antigen genes.

METHODS

cDNA inserts of positive lambda gt11 phage clones were amplified by PCR. The PCR products, after purification, were cloned into the M13 mp18 sequencing vector. Single-stranded M13 DNA was prepared and sequenced. Then the acquired sequences were compared in homologies with EMBL/GenBank database on the PC/GENE software system and searched in NCBI (National Center for Biotechnology Information) GenBank using BLAST (Basic Local Alignment Search Tool) commond.

RESULTS

Sequence C03 was part of the known P. falciparum antigenic heat shock protein 70 (Pfhsp70) gene, while the other 5 sequences were new P. falciparum antigenic expressed sequence tags (ESTs).

CONCLUSION

The 5 new antigenic ESTs generated could serve as the breaking through points in our efforts to find out new P. falciparum antigen genes.

[Cloning and sequence analysis of histidine-rich protein-II gene fragment of Plasmodium falciparum yunnan strain]

AIM

To determine the nucleotide sequence of the partial gene of the histidine-rich protein II (HRP II) the Plasmodium falciparum PFD-3/YN and find out the differences of the HRP II gene sequence between this isolate and other isolates.

METHODS

The histidine-rich protein-II gene fragment was amplified by polymerase chain reaction and cloned into M13 bacteriophage. M13-HRP II single strand DNAs of three positive clones were extracted, respectively. The nucleotide sequence of the HRP II gene fragment was determined by the dideoxy chain termination method. Using PCGENE software to compare and analyze the HRP II gene sequence among the different isolates.

RESULTS

Different degrees of diversity of the HRP II gene sequences were found among Plasmodium falciparum PFD-3/YN(from China) and two other isolates (7G8 from Brazil and D10 from Gambia). The HRP II in the three isolates exhibited 70.3% homology in amino acid sequences and 68.6% homology in the nucleic acid sequences.

CONCLUSION

There were differences in HRP II gene sequence among the Plasmodium falciparum PFD-3/YN and two other isolates (7G8 and D10).

Determination of Pranlukast and its metabolites in human plasma by LC/MS/MS with PROSPEKT on-line solid-phase extraction

A highly sensitive and selective liquid chromatography/ionspray tandem mass spectrometry (LC/MS/MS) method was developed and validated for the determination of Pranlukast and its oxidative metabolites (SB 240103, SB 241484 and SB 218663) in human plasma in order to support pharmacokinetic studies. The method employed direct injection of human plasma into an on-line solid phase extraction (SPE) PROSPEKT instrument for isolation of the analytes followed by column switching to the LC/MS/MS. The use of on-line SPE resulted in reduced sample preparation time and cleaner extracts, therefore minimizing ion suppression and HPLC back-pressures issues. The use of a 20 mM ammonium acetate-methanol system and a step gradient yielded intense ion species, excellent separation between the polar metabolites and the parent drug and sufficient selectivity for baseline resolution of the two positional isomers, SB 240103 and SB 218663. Pranlukast, its metabolites and the internal standard (SK&F 108566) were quantified using a turbo-ionspray interface by negative ion selected reaction monitoring (SRM). The lower limit of quantification (LLQ) for the assay was 10.0 ng ml-1 for Pranlukast and 1.00 ng ml-1 for its metabolites based on a 100 microliters plasma aliquot. The calibration curves were linear for analyte concentrations ranging from 10.0 to 2000 ng ml-1 for Pranlukast and 1.00 to 200 ng ml-1 for the metabolites. The calculated intra- and inter-assay precision from quality control (QC) samples resulted in mean variability values of less than 12% for all analytes. Pranlukast and its metabolites were shown to be stable under routine analysis conditions for clinical trial samples. The method provides automated sample analysis in a total cycle time of 5 min with improved robustness, sensitivity, selectivity, accuracy and reproducibility compared to the existing methodology.

Identification and determination of the enantiomers of moprolol and their metabolites in human urine by high-performance liquid chromatography and gas chromatography-mass spectrometry

A simple and sensitive high-performance liquid chromatographic (HPLC) method using chiral derivatization was developed to screen and determine the enantiomers of moprolol and their metabolites in human urine. The recovery of (+)- and (-)-moprolol from urine was 70.8-81.1% at different concentrations. The coefficients of variation (C.V.) were less than 3.2 and 6.5% for intra- and inter-assays, respectively. Moprolol could be detected in urine up to 24 h after oral administration of a 50-mg dose of moprolol. Unconjugated and conjugated enantiomers of moprolol and their metabolites were analyzed by gas chromatography (GC). A gas chromatographic-mass spectrometric (GC-MS) confirmatory method was established to identify the metabolites of moprolol. The double derivation procedure for moprolol and their metabolites with S-(-)-methyl chloroformate [(-)-MCF] and N-methyl(trimethylsilyl)trifluoroacetamide (MSTFA) gave very good GC-MS properties of the derivatized compounds and provided reliable structural information for their confirmation analysis. This is the first published report on the use of a GC-MS method for the detection of the enantiomers of moprolol and their metabolites in human urine.

Determination and identification of amiloride in human urine by high-performance liquid chromatography and gas chromatography-mass spectrometry

A simple and sensitive high-performance liquid chromatographic method was developed to screen and determine amiloride (I) in human urine. The detection limit of the method is 0.12 micrograms/ml and the recovery of amiloride from urine was 80.4-85.5% at different concentrations. The coefficients of variation were less than 2.8 and 4.4% for intra- and inter-assays, respectively. Total urinary excretion of I in 24 h after oral administration of 5 mg or 15 mg of I ranged from 22.0 to 33.3% of the total dose for three different subjects. I could be detected in urine up to at least 44 h after a 5-mg dose and 72 h after a 15-mg dose. A gas chromatographic-mass spectrometric (GC-MS) confirmatory method was established based on the methanolysis of I to methyl 3,5-diamino-6-chloropyrazine-carboxylate (II). The di-N-trimethylsilyl derivative of II showed very good GC-MS properties and provided reliable structure information for confirmation analysis of I. This is the first time that a reliable GC-MS method has been reported for the detection of urinary I.

Studies on anabolic steroids. 10. Synthesis and identification of acidic urinary metabolites of oxymetholone in a human

Two major unconjugated acidic metabolites of oxymetholone (17 beta-hydroxy-2-hydroxymethylene-17 alpha-methyl-5 alpha-androstan-3-one, 1), namely, 17 beta-hydroxy-17 alpha-methyl-2,3-seco-5 alpha-androstane-2,3-dioic acid (2) and 3 alpha,17 beta-dihydroxy-17 alpha-methyl-5 alpha-androstane-2 beta-carboxylic acid (6a), were detected by gas chromatography/mass spectrometry in urine samples collected after oral administration of 1 to a human volunteer. Reference steroid 2 was synthesized and identified. The identification of urinary metabolite 6a was based on the synthesis of its stereoisomers and the isomerization of the methyl ester 6b to its 2-epimer, 3 alpha,17 beta-dihydroxy-17 alpha-methyl-5 alpha-androstane-2 alpha-carboxylic acid methyl ester (9b). The mechanisms accounting for the formation of these acidic metabolites are discussed.