Linking seed germination and plant height: a case study of a wetland community on the eastern Tibet Plateau

Seed germination is the earliest trait expressed in a plant's life history, and it can directly affect the expression of post-germination traits. Plant height is central to plant ecological strategies, because it is a major determinant of the ability of a species to compete for light. Thus, linking seed germination and plant height at the community level is very important to understanding plant fitness and community structure. Here, we tested storage condition and temperature requirements for germination of 31 species from a wetland plant community on the eastern Tibet Plateau and analysed correlation of germination traits with plant height in relation to storage condition. Germination percentage was positively related to plant height, and this relationship disappeared when seeds were incubated at a low temperature (i.e. 5 °C) or after they were stored under wet-cold conditions. The response of seeds to dry+wet-cold storage was negatively related to plant height. Based on the scores of each species on the first two principal components derived from PCA, species were classified into two categories by hierarchical clustering, and there was a significant difference between germination and plant height of species in these two categories. These results suggest that the requirements for seed germination together with seasonal change in environmental conditions determine the window for germination and, in turn, plant growth season and resource utilisation and ultimately plant height.

Drug Interaction Potential of Osilodrostat (LCI699) Based on Its Effect on the Pharmacokinetics of Probe Drugs of Cytochrome P450 Enzymes in Healthy Adults

BACKGROUND AND OBJECTIVES

Osilodrostat (LCI699) is an adrenal steroidogenesis inhibitor currently in late-phase clinical development as a potential treatment for Cushing's disease. This study evaluated the inhibitory effect of osilodrostat on the pharmacokinetics of probe substrates of the cytochrome P450 (CYP) enzymes CYP1A2, CYP2C19, CYP2D6, and CYP3A4.

METHODS

Healthy adult volunteers received single-dose cocktail probe substrates [caffeine (100 mg), omeprazole (20 mg), dextromethorphan (30 mg), and midazolam (2 mg)] followed by a 6-day washout. Subjects then received a single dose of osilodrostat 50 mg followed by a single dose of cocktail probe substrates.

RESULTS

Nineteen of twenty subjects (ten were male) completed the study. Mean age, body weight, and body mass index were 41.8 years, 73.0 kg, and 24.4 kg/m². Geometric mean ratio of the area under the concentration-time curve from time zero to the last measureable concentration and 90% confidence intervals of probe substrate exposure with osilodrostat were: caffeine (CYP1A2 probe substrate), 2.33 (2.10-2.59); omeprazole (CYP2C19), 1.91 (1.74-2.11); dextromethorphan (CYP2D6), 1.48 (1.34-1.63); and midazolam (CYP3A4/5), 1.50 (1.41-1.60). Corresponding values for geometric mean ratio of maximum plasma concentration (90% confidence interval) for the change in substrate exposure were 1.07 (0.988-1.15), 1.61 (1.40-1.84), 1.35 (1.21-1.50), and 1.47 (1.32-1.62).

CONCLUSIONS

Osilodrostat is a moderate inhibitor of CYP1A2 and CYP2C19 and a weak inhibitor of CYP2D6 and the most clinically important CYP enzyme, CYP3A4. Osilodrostat is unlikely to significantly increase the exposures of other medications cleared by CYP3A4. These findings are clinically relevant given that Cushing's disease is a chronic condition often requiring multiple medications and that most other therapies have significant drug interaction potential.

Safety, efficacy, and pharmacokinetics of a single-tablet regimen containing elvitegravir, cobicistat, emtricitabine, and tenofovir alafenamide in treatment-naive, HIV-infected adolescents: a single-arm, open-label trial

BACKGROUND

The prodrug tenofovir alafenamide is associated with improved renal and bone safety compared with tenofovir disoproxil fumarate. We aimed to assess safety, pharmacokinetics, and efficacy of this single-tablet, fixed-dose combination of elvitegravir, cobicistat, emtricitabine, and tenofovir alafenamide in HIV-infected, treatment-naive adolescents.

METHODS

We did a 48 week, single-arm, open-label trial in treatment-naive adolescents with HIV from ten hospital clinics in South Africa, Thailand, Uganda, and the USA. Eligible participants were aged 12-18 years, with plasma HIV-1 RNA of at least 1000 copies per mL, a CD4 count of at least 100 cells per μL, and estimated glomerular filtration rate of at least 90 mL/min per 1·73 m² by the Schwartz formula, bodyweight of at least 35 kg, and an HIV-1 genotype with sensitivity to elvitegravir, emtricitabine, and tenofovir. Participants received a single-tablet regimen once per day with food (administered by their parent or carer) containing 150 mg elvitegravir, 150 mg cobicistat, 200 mg emtricitabine, and 10 mg tenofovir alafenamide. Study visits to the clinic occurred at weeks 1, 2, 4, 8, 12, 16, 24, 32, 40, and 48. The coprimary endpoints were the pharmacokinetic parameters of area under the curve (AUC) concentration at the end of the dosing interval (AUC_tau) for elvitegravir and the AUC from time zero to the last quantifiable concentration (AUC_last) for tenofovir alafenamide, incidence of treatment-emergent serious adverse events, and all adverse events that emerged after treatment started (including data for bone mineral density). All participants who received one dose of study drug were included in the primary and safety analyses. This trial is registered with ClinicalTrials.gov, number NCT01854775.

FINDINGS

Between May 22, 2013, and July 22, 2014, we enrolled 50 participants, and all 50 received the assigned treatment; 24 participated in the intensive pharmacokinetic assessment. 48 patients completed the 48 weeks of treatment; two discontinued (one withdrew consent at week 8, one was lost to follow-up at week 12). The regimen was well tolerated and no discontinuations related to adverse events occurred. The mean AUC_tau for elvitegravir was 23 840 ng × h per mL (coefficient of variation [CV] 25·5%), and the mean AUC_last for tenofovir alafenamide was 189 ng × h per mL (CV 55·8%). Four participants (8%) had a serious adverse event, one of which (intermediate uveitis) was deemed related to the study regimen but resolved without treatment interruption. The most common study drug-related adverse events were nausea (in ten participants), abdominal pain (in six), and vomiting (in five). Exposures to the elvitegravir, cobicistat, emtricitabine, and tenofovir alafenamide regimen were similar to those previously noted in adults.

INTERPRETATION

The elvitegravir, cobicistat, emtricitabine, and tenofovir alafenamide regimen was well tolerated and achieved component plasma pharmacokinetic exposures similar to those in adults. Although non-comparative with a small sample size, these data support the use of this regimen in HIV-infected adolescents and its timely assessment in younger children.

FUNDING

Gilead Sciences.

Resting-state functional connectivity density mapping of etiology confirmed unilateral pulsatile tinnitus patients: Altered functional hubs in the early stage of disease

Functional magnetic resonance imaging (fMRI) has been widely used to identify altered intrinsic local neural activities and global networks of tinnitus patients. In this study, functional connectivity density (FCD) mapping, a newly developed voxelwise data-driven method based on fMRI, was applied for the first time to measure the functional reorganization pattern in thirty-two unilateral pulsatile tinnitus (PT) patients in the early stage of disease (less than 48 months). FCD analysis was employed to compute short-range and long-range FCD values. A correlation analysis with clinical variables was also performed. Compared with normal controls, PT patients showed significantly increased short-range FCD, mainly in the precuneus (PCu), bilateral inferior frontal gyrus (IFG) and middle occipital gyrus (MOG), and increased long-range FCD in the PCu, posterior cingulate cortex (PCC), and bilateral middle frontal gyrus (MFG). In addition, correlation analysis showed positive correlations between PT duration and short-range FCD values in the right MOG. Positive correlations were also found between the disease duration and the long-range FCD value in the PCC. The increased short-/long-range FCD in bilateral dorsal visual areas indicated that the enhanced pathway between the auditory cortex and bilateral dorsal visual areas may have activated the "auditory occipital activations" (AOAs) pathway. The bilaterally altered FCD values in the dorsal visual areas reflected the cooperation of different brain areas. This study is a foundation of the connectivity research in PT patients. Our work may advance the understanding of the disrupted neural network of patients with PT.

Plasma EBV DNA and cell-free GAPDH DNA as prognostic factors of locally advanced nasopharyngeal carcinoma

6053

Background: Plasma cell-free nucleic acids have been investigated to be potential prognostic and predictive markers of treatment response, residual disease, and survival of cancer patients. However, these nucleic acids will be confounded by normal cell death, which might be caused by cancer-related inflammation, infection, or chemotherapy. Nasopharyngeal carcinoma is endemic in Taiwan, highly related to EBV infection. Plasma EBV DNA level has been suggested to be predictive of disease status and outcomes. We try to find out whether plasma EBV and cell-free glyceraldehydes-3-phosphate dehydrogenase DNA before definite treatment of locally advanced NPC predict tumor outcomes better. Methods: 144 stage IV (AJCC version 6) NPC patients received induction chemotherapy followed by concurrent chemoradiotherapy in National Taiwan University Hospital from 1998 to 1999. Pre-treatment blood samples were colleted for real-time quantitative polymerase chain reactions of EBV and GAPDH DNA. The results will be analyzed by SPSS version 13 to see if correlated with tumor extent, locoregional/distant failure, and overall survival. Results: Our patients were mainly composed of T4(97%) and N2(56%) patients. 23 % were in N3 stage. Plasma EBV and cell-free GAPDH DNA levels were not correlated with T stage. Plasma EBV DNA level was significantly correlated with N3 status(Mann-Whitney test p=0.021). After Cox regression model, only age (p=0.024) was a significant predictor of recurrence-free survival; N3 status(p=0.007) and positive plasma EBV DNA (p=0.002) predicted shorter metastasis-free survival. N3 status (p=0.031) and positive plasma EBV DNA (p=0.002) were significantly related to poor survival by log-rank test; whereas T4 lesions (p=0.524) and plasma cell-free GAPDH DNA level (p=0.182) were not. After multivariate Cox regression, positive plasma EBV DNA (hazard ratio 4.936 p=0.006) was the only significant predictor of poor survival. Conclusions: To use circulating DNA as prognostic marker, a specific one, such as EBV DNA, might be better than a non-specific one, like GAPDH DNA. This is important in the development of tumor markers for other solid tumors.

No significant financial relationships to disclose.

Simplification of therapeutic drug monitoring for twice-daily regimens of lopinavir/ritonavir for HIV infection

Cost and inconvenience limit the application of full 12-hour pharmacokinetic (PK) analysis for routine therapeutic drug monitoring of antiretroviral medications. We explore whether lopinavir (LPV) and ritonavir (RTV) exposures can be estimated with limited sampling for patients taking twice-daily LPV/RTV. One hundred and one PK profiles from 81 patients, most receiving salvage therapies including twice-daily LPV/RTV, were obtained for the analysis. After a minimum of 2 weeks on a stable regimen, blood was drawn immediately before and at 1, 2, 4, 6, 8, 10, and 12 hours after a timed medication dose. Plasma drug concentrations were determined by a validated HPLC-MS-MS assay. Peak concentrations, evening troughs, and AUC0-12 h were entered into linear and log10-log10 linear regression models to determine the best correlation with LPV and RTV plasma concentrations using a maximum of 2 time points. The accuracy and precision of PK parameter estimates of the resultant models were tested on data collected for an additional 25 patients. Twelve models using various combinations of 2 timed LPV concentrations afforded accurate (maximum % bias = -6.45) and precise (relative standard deviation < 15%) estimates for the LPV peak concentration or AUC0-12h. Four sets of 2 concentrations provided simultaneous estimates of both PK parameters, with the best estimates derived from data collected at 2 and 6 hours postdose. Evening trough concentrations were the best estimators of the daily nadir; however, no adequate substitute for collecting blood 12 hours postdose emerged from this analysis.

Changes in mitochondrial DNA as a marker of nucleoside toxicity in HIV-infected patients

BACKGROUND

Nucleoside analogues can induce toxic effects on mitochondria by inhibiting the human DNA polymerase gamma. The toxic effects can range from increased serum lactate levels to potentially fatal lactic acidosis. We studied changes in mitochondrial DNA relative to nuclear DNA in the peripheral-blood cells of patients with symptomatic, nucleoside-induced hyperlactatemia.

METHODS

Total DNA was extracted from blood cells. A nuclear gene and a mitochondrial gene were quantified by real-time polymerase chain reaction. Three groups were studied: 24 controls not infected with the human immunodeficiency virus (HIV), 47 HIV-infected asymptomatic patients who had never been treated with antiretroviral drugs, and 8 HIV-infected patients who were receiving antiretroviral drugs and had symptomatic hyperlactatemia. The patients in the last group were studied longitudinally before, during, and after antiretroviral therapy.

RESULTS

Symptomatic hyperlactatemia was associated with marked reductions in the ratios of mitochondrial to nuclear DNA, which, during therapy, averaged 68 percent lower than those of non-HIV-infected controls and 43 percent lower than those of HIV-infected asymptomatic patients never treated with antiretroviral drugs. After the discontinuation of antiretroviral therapy, there was a statistically significant increase in the ratio of mitochondrial to nuclear DNA (P=0.02). In the patients followed longitudinally, the decline in mitochondrial DNA preceded the increase in venous lactate levels.

CONCLUSIONS

Mitochondrial DNA levels are significantly decreased in patients with symptomatic, nucleoside-related hyperlactatemia, an effect that resolves on the discontinuation of therapy.

Simple rapid method for quantification of antiretrovirals by liquid chromatography-tandem mass-spectrometry

OBJECTIVES

The aim of the current study was to develop a simple, fast and universal method for quantification of any combination of all currently marketed anti-HIV drugs in human plasma, using a LC-tandem mass spectrometer (API-2000, SCIEX, Toronto, Canada).

METHODS

80 microL plasma were spiked with internal standard (cimetidine), and protein precipitated with 200 microL acetonitrile. The sample was centrifuged and 30 microL aliquot was injected onto the HPLC column, where it underwent an online extraction with ammonium acetate. After that the automatic switching valve was activated, changing the mobile phase to methanol and thereby eluting the analytes into the tandem mass spectrometer. Stavudine, AZT and efavirenz were analyzed in the negative MS/MS mode, while all other drugs were analyzed in the positive mode. The high selectivity of a tandem mass analyzer allows determination of any combination of the drugs within a 4.5 min run.

RESULTS

Between-day precision was below 10% for all analytes at the concentrations tested. Accuracy ranged between 95% and 105% (n = 20). The method was linear over the measuring ranges of all analytes. Within-run precision gave a CV < 7% for all analytes. Good correlation with other analytical methods was observed.

CONCLUSIONS

The simplicity, universality and high throughput of the method make it suitable for application in a clinical laboratory. The method has been implemented in our laboratory for routine use.

Internal poverty and teen pregnancy

The subjects for the present study were drawn from the female students who participated in the National Education Longitudinal Study (NELS) initial eighth-grade data collection. Adolescent females who later became pregnant were matched on race, birth month, and birth year with adolescent females who did not report a pregnancy. The study examined selected predictor variables from the baseline 1988 wave of data in relation to the outcome variable of pregnancy status. Results indicated a statistically significant difference in locus of control between those females who later became pregnant and those who later did not experience a pregnancy during adolescence. Those who later became pregnant were much more likely to have an external locus of control (p = .0001). Females who later became pregnant were also more likely to have a poorer sense of personal efficacy (p = .0001). Finally, females who later experienced a teen pregnancy had more traditional occupational expectations (p = .006) and lower educational expectations (p = .001) than did those who did not later report a teen pregnancy.

Transplantation of IL-2-mobilized autologous peripheral blood progenitor cells for adults with acute myelogenous leukemia in first remission

In order to improve leukemia-free survival we evaluated the feasibility and efficacy of autologous transplantation of interleukin-2 (IL-2)-mobilized peripheral blood progenitor cells for adult patients with acute myelogenous leukemia in first remission. Forty-nine consecutive patients (median age 49, range 21-70) with acute myelogenous leukemia in first remission were enrolled on a study of high-dose cytarabine/mitoxantrone consolidation chemotherapy with post-recovery IL-2 used as a method of in vivo purging for the purpose of autologous peripheral blood progenitor cell transplantation. A median of 2.08 x 10(6) CD34+ peripheral blood progenitor cells/kg were infused 1 day after preparative conditioning with 11.25 Gy total body irradiation and cyclophosphamide (120 mg/kg). Forty-one patients received myeloablative chemoradiotherapy followed by the infusion of IL-2-mobilized autologous peripheral blood progenitor cells. The median times to both neutrophil and platelet recovery were 16 days (range, 2-43) and 23 days (8-318+ days), respectively. Twenty-seven patients remain alive with 24 in continued first complete remission. Median remission duration for all eligible patients is 8 months, and actuarial leukemia-free survival is 49+/-15%. The actuarial risk of relapse is 43+/-16%. Toxicity of autologous peripheral blood progenitor cell transplant included treatment-related death in three patients and serious organ toxicity in 12. Advanced age was a negative prognostic factor for leukemia-free survival. Results were compared to an age-matched historical control treated with autologous transplantation of chemotherapy-mobilized progenitor cells; no significant difference in favor of IL-2 mobilization could be demonstrated. Our results demonstrate that autologous transplantation of IL-2-mobilized peripheral blood progenitor cells is feasible in an unselected population of adult patients with acute myelogenous leukemia in first remission with minimal toxicity but no clear evidence of benefit in leukemia-free survival.

Familial nasal NK/T-cell lymphoma and pesticide use

Familial occurrence of nasal NK/T-cell lymphoma (NNKTCL) in pesticide users is presented. The proband (71 years old, male) and son (39 years old) were both diagnosed with NNKTCL within interval of 26 months. Laboratory data showed slight anemia, with no abnormal cells in peripheral blood. They and their wives were farmers and used large amounts of pesticides (fungicides and insecticides) in the hothouse. NNKTCL did not develop in the wives. Proband's father was diagnosed with malignant lymphoma of the neck and died of the disease. Genetic analyses of the peripheral blood leukocytes and tumor tissues did not show p53 and k-ras gene mutations and microsatellite instability. Metaphase cells from peripheral blood leukocytes bore specific marker chromosomes (father, 44XY,-14,-17,-18,-22,+2mar; son, 46XY,-17,+1mar). Environmental exposures to pesticides in conjunction with familial or genetic factors might increase the risk for NNKTCL.

Identification of functional domains of rat intestinal phospholipase B/lipase. Its cDNA cloning, expression, and tissue distribution

A cDNA encoding a rat intestinal Ca(2+)-independent phospholipase B/lipase (PLB/LIP) was cloned from an ileac mucosa cDNA library using a probe amplified by polymerase chain reaction based on the purified enzyme's sequence. PLB/LIP consists of an NH2-terminal signal peptide, four tandem repeats of about 350 amino acids each, and a hydrophobic domain near the COOH terminus. The enzyme purified previously was found to be derived from the second repeat part. To examine the function of each domain, the full-length PLB/LIP, individual repeats, and a protein lacking the COOH-terminal hydrophobic stretch were expressed in COS-7 cells. The results showed that the second repeat, but not the other repeats, had all the activities (phospholipase A2, lysophospholipase, and lipase) found in the purified natural and expressed full-length enzymes, suggesting repeat 2 is a catalytic domain. The full-length enzyme was mainly present in membrane fractions and efficiently solubilized by treatment with 1% Triton X-100, but not with phosphatidylinositol-specific phospholipase C. Deletion of the COOH-terminal hydrophobic stretch caused the secretion of > 90% of synthesized PLB/LIP into culture media. These results suggest the hydrophobic domain is not replaced by a glycosylphosphatidylinositol anchor but serves as a membrane anchor directly. A message of the full-length PLB/LIP was abundantly expressed in the ileum and also, in a smaller, but significant amount, in the esophagus and testis. Immunohistochemistry showed that PLB/LIP is localized in brush border membranes of the absorptive cells, Paneth cells, and acrosomes of spermatid, suggesting its roles related and unrelated to intestinal digestion.

EXOSKELETAL STRAIN: EVIDENCE FOR A TROT-GALLOP TRANSITION IN RAPIDLY RUNNING GHOST CRABS

Equivalent gaits may be present in pedestrians that differ greatly in leg number, leg design and skeletal type. Previous studies on ghost crabs found that the transition from a slow to a fast run may resemble the change from a trot to a gallop in quadrupedal mammals. One indication of the trot-gallop gait change in quadrupedal mammals is a distinct alteration in bone strain. To test the hypothesis that ghost crabs (Ocypode quadrata) change from a trot to a gallop, we measured in vivo strains of the meropodite of the second trailing leg with miniature strain gauges. Exoskeletal strains changed significantly (increased fivefold) during treadmill locomotion at the proposed trot-gallop transition. Maximum strains attained during galloping and jumping (1000×10-6-3000×10-6) were similar to the values reported for mammals. Comparison of the maximum load possible on the leg segment (caused by muscular tension) with the strength of the segment under axial loading revealed a safety factor of 2.7, which is similar to values measured for jumping and running mammals. Equivalent gaits may result from similarities in the operation of pedestrian locomotory systems.

The effect of nitroimidazoles on the oxygen consumption rate and respiratory control ratio of beef heart mitochondria

The neurotoxic effect of the nitroimidazole radiosensitizers misonidazole (MISO) and desmethylmisonidazole (DMM) has seriously compromised their clinical effectiveness. We compare here the effect of MISO and DMM on oxygen consumption in purified beef heart mitochondria. MISO has been found to significantly increase the oxygen consumption rate and decrease the respiratory control ratio in isolated mitochondria when incubated in the presence of the NAD+ dependent substrate, beta-hydroxybutyrate. DMM has a similar but less pronounced effect than MISO on these respiratory parameters. When mitochondria were incubated in the presence of these radiosensitizers for 8, 15, 30, 45, and 60 minutes, the oxygen consumption rate was decreased when succinate, a FAD dependent substrate, was added following the incubation. This decrease, which is both time and dosage dependent, is equivalent for MISO and DMM.