The use of multiple imputation for the accurate measurements of individual feed intake by electronic feeders

Obtaining accurate individual feed intake records is the key first step in achieving genetic progress toward more efficient nutrient utilization in pigs. Feed intake records collected by electronic feeding systems contain errors (erroneous and abnormal values exceeding certain cutoff criteria), which are due to feeder malfunction or animal-feeder interaction. In this study, we examined the use of a novel data-editing strategy involving multiple imputation to minimize the impact of errors and missing values on the quality of feed intake data collected by an electronic feeding system. Accuracy of feed intake data adjustment obtained from the conventional linear mixed model (LMM) approach was compared with 2 alternative implementations of multiple imputation by chained equation, denoted as MI (multiple imputation) and MICE (multiple imputation by chained equation). The 3 methods were compared under 3 scenarios, where 5, 10, and 20% feed intake error rates were simulated. Each of the scenarios was replicated 5 times. Accuracy of the alternative error adjustment was measured as the correlation between the true daily feed intake (DFI; daily feed intake in the testing period) or true ADFI (the mean DFI across testing period) and the adjusted DFI or adjusted ADFI. In the editing process, error cutoff criteria are used to define if a feed intake visit contains errors. To investigate the possibility that the error cutoff criteria may affect any of the 3 methods, the simulation was repeated with 2 alternative error cutoff values. Multiple imputation methods outperformed the LMM approach in all scenarios with mean accuracies of 96.7, 93.5, and 90.2% obtained with MI and 96.8, 94.4, and 90.1% obtained with MICE compared with 91.0, 82.6, and 68.7% using LMM for DFI. Similar results were obtained for ADFI. Furthermore, multiple imputation methods consistently performed better than LMM regardless of the cutoff criteria applied to define errors. In conclusion, multiple imputation is proposed as a more accurate and flexible method for error adjustments in feed intake data collected by electronic feeders.

MiR-125a promotes paclitaxel sensitivity in cervical cancer through altering STAT3 expression

Cervical cancer (CC) is one of the most common malignancies in women. Paclitaxel is the front-line chemotherapeutic agent for treating CC. However, its therapeutic efficacy is limited because of chemoresistance, the mechanism of which remains poorly understood. Here, we used microRNA (miRNA) arrays to compare miRNA expression levels in the CC cell lines, HeLa and CaSki, with their paclitaxel resistance counterparts, HeLa/PR and CaSki/PR. We demonstrate that miR-125a was one of most significantly downregulated miRNAs in paclitaxel-resistant cells, which also acquired cisplatin resistance. And that the upregulation of miR-125a sensitized HeLa/PR and CaSki/PR cells to paclitaxel both in vitro and in vivo and to cisplatin in vitro. Moreover, we determined that miR-125a increased paclitaxel and cisplatin sensitivity by downregulating STAT3. MiR-125a enhanced paclitaxel and cisplatin sensitivity by promoting chemotherapy-induced apoptosis. Clinically, miR-125a expression was associated with an increased responsiveness to paclitaxel combined with cisplatin and a more favorable outcome. These data indicate that miR-125a may be a useful method to enable treatment of chemoresistant CC and may also provide a biomarker for predicting paclitaxel and cisplatin responsiveness in CC.

STRIPAK complexes in cell signaling and cancer

Striatin-interacting phosphatase and kinase (STRIPAK) complexes are striatin-centered multicomponent supramolecular structures containing both kinases and phosphatases. STRIPAK complexes are evolutionarily conserved and have critical roles in protein (de)phosphorylation. Recent studies indicate that STRIPAK complexes are emerging mediators and regulators of multiple vital signaling pathways including Hippo, MAPK (mitogen-activated protein kinase), nuclear receptor and cytoskeleton remodeling. Different types of STRIPAK complexes are extensively involved in a variety of fundamental biological processes ranging from cell growth, differentiation, proliferation and apoptosis to metabolism, immune regulation and tumorigenesis. Growing evidence correlates dysregulation of STRIPAK complexes with human diseases including cancer. In this review, we summarize the current understanding of the assembly and functions of STRIPAK complexes, with a special focus on cell signaling and cancer.

Toxicity and adverse effects of everolimus in the treatment of advanced nonsmall cell lung cancer pretreated with chemotherapy--Chinese experiences

BACKGROUND

There is not more treatment selection for advanced nonsmall-cell lung cancer (NSCLC) patients who had disease progression after two previous treatments. Everolimus is an oral inhibitor of the mammalian target of rapamycin pathway, which is aberrantly activated in NSCLC.

PATIENTS AND METHODS

Stage IV NSCLC patients, with one or multiple prior chemotherapy regimens, received everolimus 5-10 mg/day with or without chemotherapy until progression or unacceptable toxicity. The primary objective were toxicity of everolimus and overall disease control rate (DCR).

RESULTS

22 patients were enrolled. Common ≥ grade 3 events were stomatitis, dyspnea, vomiting, thrombocytopenia. Overall disease control rate was 54.5% among 22 patients, 1 had a partial response, and 11 had disease stabilization. Common ≥ Grade 3 events were stomatitis, dyspnea, vomiting, and thrombocytopenia.

CONCLUSION

Everolimus was well tolerated, showing the modest clinical activity in heavily pretreated advanced NSCLC.

Feed intake, average daily gain, feed efficiency, and real-time ultrasound traits in Duroc pigs: II. Genomewide association

Efficient use of feed resources has become a clear challenge for the U.S. pork industry as feed costs continue to be the largest variable expense. The availability of the Illumina Porcine60K BeadChip has greatly facilitated whole-genome association studies to identify chromosomal regions harboring genes influencing those traits. The current study aimed at identifying genomic regions associated with variation in feed efficiency and several production traits in a Duroc terminal sire population, including ADFI, ADG, feed conversion ratio, residual feed intake (RFI), real-time ultrasound back fat thickness (BF), ultrasound muscle depth, intramuscular fat content (IMF), birth weight (BW at birth), and weaning weight (BW at weaning). Single trait association analyses were performed using Bayes B models with 35,140 SNP on 18 autosomes after quality control. Significance of nonoverlapping 1-Mb length windows (n = 2,380) were tested across 3 QTL inference methods: posterior distribution of windows variances from Monte Carlo Markov Chain, naive Bayes factor, and nonparametric bootstrapping. Genes within the informative QTL regions for the traits were annotated. A region ranging from166 to 140 Mb (4-Mb length) on SSC 1, approximately 8 Mb upstream of the MC4R gene, was significantly associated with ADFI, ADG, and BF, where SOCS6 and DOK6 are proposed as the most likely candidate genes. Another region affecting BW at weaning was identified on SSC 4 (84-85 Mb), harboring genes previously found to influence both human and cattle height: PLAG1, CHCHD7, RDHE2 (or SDR16C5), MOS, RPS20, LYN, and PENK. No QTL were identified for RFI, IMF, and BW at birth. In conclusion, we have identified several genomic regions associated with traits affecting nutrient utilization that could be considered for future genomic prediction to improve feed utilization.

Structural dissection of Hippo signaling

The Hippo pathway controls cell number and organ size by restricting cell proliferation and promoting apoptosis, and thus is a key regulator in development and homeostasis. Dysfunction of the Hippo pathway correlates with many pathological conditions, especially cancer. Hippo signaling also plays important roles in tissue regeneration and stem cell biology. Therefore, the Hippo pathway is recognized as a crucial target for cancer therapy and regeneration medicine. To date, structures of several key components in Hippo signaling have been determined. In this review, we summarize current available structural studies of the Hippo pathway, which may help to improve our understanding of its regulatory mechanisms, as well as to facilitate further functional studies and potential therapeutic interventions.

Neuroprotective effects of argatroban and C5a receptor antagonist (PMX53) following intracerebral haemorrhage

Intracerebral haemorrhage (ICH) is a subtype of stroke that associated with neurological dysfunction and inflammation, which may be ameliorated by a neuroprotective strategy targeting the complement cascade. The protective effect of C5a-receptor antagonist (PMX53) solely and in combination with thrombin antagonist (argatroban) was investigated in the ICH mouse model, respectively. Adult male C57BL/6J wild-type (WT) mice and C3(-/-) mice were randomized to receive PMX53/argatroban 1, 3 and 5 days after ICH. A double injection technique was used to infuse 25 μl of autologous whole blood into the right striatum. Mice in the sham group received only needle insertion. Brain water content and mRNA of inflammatory factors were measured on the first, third and fifth days after ICH, respectively. Neurological dysfunction was assessed using a 28-point neurological scoring system in the three cohorts, namely, on days 1, 3 and 5 following ICH. Animals treated with PMX53/argatroban demonstrated significant improvements in neurological function and fewer neurological apoptosis detected by TUNEL [terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick end-labelling] and βIII-tubulin dual-staining compared with vehicle-treated animals. Compared with sham-treated mice, the brain water content in argatroban/PMX53-treated mice was decreased significantly in both the ipsilateral cortex and ipsilateral striatum. Administration of PMX53/argatroban provided a synergistic neuroprotective effect via reducing inflammatory factors and brain oedema, leading to improvements in neurofunctional outcome. The results of this study indicated that simultaneous blockade of the thrombin and C5a receptors represent a promising neuroprotective strategy in haemorrhagic stroke.

Feed intake, average daily gain, feed efficiency, and real-time ultrasound traits in Duroc pigs: I. Genetic parameter estimation and accuracy of genomic prediction

The efficiency of producing salable products in the pork industry is largely determined by costs associated with feed and by the amount and quality of lean meat produced. The objectives of this paper were 1) to explore heritability and genetic correlations for growth, feed efficiency, and real-time ultrasound traits using both pedigree and marker information and 2) to assess accuracy of genomic prediction for those traits using Bayes A prediction models in a Duroc terminal sire population. Body weight at birth (BW at birth) and weaning (BW at weaning) and real-time ultrasound traits, including back fat thickness (BF), muscle depth (MD), and intramuscular fat content (IMF), were collected on the basis of farm protocol. Individual feed intake and serial BW records of 1,563 boars obtained from feed intake recording equipment (FIRE; Osborne Industries Inc., Osborne, KS) were edited to obtain growth, feed intake, and feed efficiency traits, including ADG, ADFI, feed conversion ratio (FCR), and residual feed intake (RFI). Correspondingly, 1,047 boars were genotyped using the Illumina PorcineSNP60 BeadChip. The remaining 516 boars, as an independent sample, were genotyped with a low-density GGP-Porcine BeadChip and imputed to 60K. Magnitudes of heritability from pedigree analysis were moderate for growth, feed intake, and ultrasound traits (ranging from 0.44 ± 0.11 for ADG to 0.58 ± 0.09 for BF); heritability estimates were 0.32 ± 0.09 for FCR but only 0.10 ± 0.05 for RFI. Comparatively, heritability estimates using marker information by Bayes A models were about half of those from pedigree analysis, suggesting "missing heritability." Moderate positive genetic correlations between growth and feed intake (0.32 ± 0.05) and back fat (0.22 ± 0.04), as well as negative genetic correlations between growth and feed efficiency traits (-0.21 ± 0.08, -0.05 ± 0.07), indicate selection solely on growth traits may lead to an undesirable increase in feed intake, back fat, and reduced feed efficiency. Genetic correlations among growth, feed intake, and FCR assessed by a multiple-trait Bayes A model resulted in increased genetic correlation between ADG and ADFI, a negative correlation between ADFI and FCR, and a positive correlation between ADG and FCR. Accuracies of genomic prediction for the traits investigated, ranging from 9.4% for RFI to 36.5% for BF, were reported that might provide new insight into pig breeding and future selection programs using genomic information.

A phase II, open-label, multicenter, prospective study of paclitaxel plus capecitabine with subsequent capecitabine maintenance therapy as first-line treatment for metastatic or recurrent gastric cancer

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Background: Paclitaxel has been shown to be effective in AGC. We assess the efficacy and safety of PX-X therapy as first-line treatment for metastatic or recurrent GC in a phase II, multicenter, prospective study.

Methods: Patients with previously untreated gastric adenocarcinoma, signed informed consent, target lesion(s), KPS ≥ 70 and adequate organ functions are eligible. Paclitaxel was given as 80 mg/m2 by 3-hour infusion day 1,8, capecitabine 1,000 mg/m2, BID, D1-14, Q3W. Cycles were repeated until progression or maximum 6 or AEs. Then the patients without progression began the second stage treatment as X with same dose/schedule until progression or AEs. PFS, RR, DCR, OS and AEs are the end points evaluated in this study.

Results: From 12/2006 to 4/2010, 195 patients (ITT) were enrolled in 21 centers, 1 patient was withdraw due to allergy to paclitaxel, 194 cases were PP. After median follow up of 16.2 months, 16 cases lost. In ITT, 119 pts progressed, 104 pts died. Mean cycles the patients completed was 5. CR and PR were achieved in 1.0% (2 pts) and 32.3% (63 pts) of pts (RR 33.3%), 75 pts had SD (38.5%), 25 pts (12.8%) progressed. PFS of ITT is 208 d (95% CI: 169.1-246.8) and estimated OS is 456 d (95%CI: 286.9-624.2). 45 pts continued to X after PX with good tolerance, median cycles accepted was 4, and OS was longer than 590 d. 23 patients accepted surgery after chemotherapy; the survival data have not been reached. After disease progression, 61 cases accepted second-line treatment, including oxaplatin/irinotecan-based chemotherapy, target therapy, and local therapy. AEs were mild and the grade 3/4 toxicities were leucopenia (13.8%), alopecia(13.3%), neutropenia (8.2%), fatigue (6.7%), nausea/vomiting (5.1%), HFS (5.1%), diarrhea(3.6%), neurotoxicity (3.1%), hepatic dysfuction (2.6%), and anaphylactic shock (0.5%). No treatment- related deaths were recorded in all patients.

Conclusions: PX-X as first-line treatment was promising in advanced gastric cancer. Further evaluation of this combination therapy is being carried on phase III clinical trial of ML22697.

No significant financial relationships to disclose.

Gastrointestinal and Cardiovascular Safety Profiles of Neratinib Monotherapy in Patients with Advanced ErbB2-Positive Breast Cancer

Background: In a phase 2 study, oral neratinib was administered to patients (pts) with advanced breast cancer in 2 cohorts, those with prior trastuzumab treatment (prior T, n=66) and those with no prior trastuzumab treatment (no prior T, n=70). Neratinib demonstrated robust antitumor activity with objective response rates of 26% and 51%, respectively, and was generally tolerable (Burstein et al. Cancer Res 2009;69:72S). Diarrhea, all grades, occurred in 89% of total pts. Characteristics of the diarrhea and left ventricular ejection fraction (LVEF) measurements are described. Methods: Pts were required to have ErbB2 gene amplification in tumor tissue as measured by fluorescence in situ hybridization by independent assessment. Serial LVEF measurements were made with a multigated acquisition scan or echocardiogram. Pts were ineligible if baseline LVEF was <50%. Adverse events were graded based on the NCI Common Terminology Criteria, v 3.0. Pts received oral neratinib 240 mg daily. Results: Data collected by 18 Mar 2009 are reported; the median (range) duration of neratinib treatment was 4.5 (0.2-23.5) months for pts with prior T and 7.8 (0.5-24.2) months for pts with no prior T. Diarrhea, all grades occurred in 93% of the total population (prior T: 97%, no prior T: 89%); grade 3-4 diarrhea occurred in 21% of the total population (prior T: 30%, no prior T: 13%). Median times of onset were 2 and 3 days after first dose of neratinib, respectively, and median durations of diarrhea were 7 and 5 days. In study week 1, 86% and 73% of pts with prior T and no prior T, respectively, had diarrhea; this decreased to 12-14% in months 3 and 4 (Table). Diarrhea was the cause of dose interruptions in 36% of pts with prior T and 11% of pts with no prior T and of dose reductions in 30% of pts with prior T and 5% of pts with no prior T; only 1 pt (prior T) discontinued treatment due to diarrhea. Pts used anti-diarrheal medications for supportive therapy (prior T: 91%, no prior T: 67%). For LVEF measurements, there was little variation from baseline in most pts during the study. Four pts had at least 1 LVEF measurement <50% (2 of these pts had measurements within the institutional range of normal). None had congestive heart failure. One of these pts had grade 3 atrioventricular block and grade 3 bradycardia, which were considered unrelated to neratinib. Discussion: Neratinib treatment was not associated with clinically significant cardiotoxicity. Pts who developed diarrhea with neratinib monotherapy had early onset, but frequency and severity decreased with time on study. Despite the high frequency of diarrhea with neratinib treatment, it was readily managed with supportive therapy and dose interruptions and/or reductions.Time Course of Diarrhea in ErbB2-Positive Breast Cancer Patients Treated With NeratinibStudy PeriodPrior T: No. on StudyPrior T: % With Diarrhea, All Grades*Prior T: % With Diarrhea, Gr 3-4*No Prior T: No. on StudyNo Prior T: % With Diarrhea, All Grades*No Prior T: % With Diarrhea, Gr 3-4*Week 166861770737Week 2-466611170436Month 260331066152Month 34713060120Month 44312058140*For pts with multiple toxicity grades in a period, the maximum grade was reported.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 5096.

Lack of effect of SU1498, an inhibitor of vascular endothelial growth factor receptor-2, in a transgenic murine model of retinoblastoma

SU1498, a tyrosine kinase inhibitor of vascular endothelial growth factor receptor 2 (VEGFR-2), has activity against retinal neovascular diseases. To determine if this drug might have clinical utility against retinoblastoma, we evaluated the effects of SU1498, as well as the expression of VEGFR-2, in a transgenic animal model of retinoblastoma. Optical coherence tomography (OCT) was evaluated as a technology to measure retinal tumors in vivo, in response to treatment. Immunofluorescence analysis was performed to evaluate the distribution and expression of VEGFR-2 in enucleated eyes from LHβTag transgenic mice and controls at 4, 8, 12, and 16 weeks of age. VEGFR-2 and phosphorylated (p)VEGFR-2 levels were quantitated by Western blot. OCT was used to pair 10-week-old animals based on tumor volume (n=10), and these animals were treated with 6 periocular injections of SU1498 (50mg/kg, given twice weekly) or vehicle for 3 weeks. Tumor burden was determined by histology and in vivo imaging by OCT. VEGFR-2 and pVEGFR-2 expression levels were upregulated during tumorigenesis. However, SU1498 did not significantly reduce tumor burden compared to vehicle (p=0.29). OCT imaging of one matched pair demonstrated equivalent, linear tumor growth despite treatment with SU1498. Retinal tumors can be followed non-invasively and quantitatively measured with OCT. VEGFR-2 is strongly upregulated during tumorigenesis in transgenic retinoblastoma; however, SU1498 does not decrease tumor volume in transgenic murine RB at the studied dose and route of administration.

A phase II trial of trastuzumab (H) + capecitabine (X) as first-line treatment in patients (pts) with HER2-positive metastatic breast cancer (MBC)

10615

Background: The addition of H to a taxane provides significant clinical benefit, including prolonged survival, in HER2-positive MBC. H adds little to the toxicity of taxanes alone. As monotherapy, X has consistently high activity and favorable safety. The addition of X to docetaxel extends survival in MBC. Preliminary data [Bangemann et al. 2000] indicated that the combination of H + X is effective and well-tolerated for intensively pretreated HER2-positive MBC (ORR 47%). The current study evaluated the efficacy and safety of H + X in first-line MBC. Methods: 72 pts of a planned population of 100 pts were enrolled between Mar03 and Dec05. All pts had measurable (WHO criteria), HER2-positive (IHC 3+ or IHC 2+/FISH positive) and untreated MBC, KPS ≥60, and adequate organ function. H was administered as a 4mg/kg loading dose followed by 2mg/kg i.v. weekly (until disease progression) and X 1250mg/m2 bid d1–14 q3w (max 6 cycles). The primary endpoint was progression-free survival (PFS). Results: Baseline characteristics: median age 49 years (range 27–74), median KPS 90 (range 60–100). Principal tumor sites: lymph nodes (49%), lung (33%), liver (28%), breast (14%), thoracic wall (9%), chest (9%), other (12%). Prior treatment: surgery (77%), radiotherapy (21%), and adjuvant chemotherapy (58%), including anthracycline (35%), paclitaxel (7%), docetaxel (7%) and other (21%). 43 pts are evaluable for safety and efficacy. The remaining 29 pts are being analyzed. 6 pts received 3 cycles of H + X; the other 37 pts completed 6 cycles of treatment. 16 pts received H monotherapy after completing 6 cycles of H + X. 3 pts discontinued H due to disease progression. The most common grade 1/2 adverse events (AEs) were HFS (14%), neutropenia (14%), SGOT abnormality (16%), and SGPT abnormality (14%). Grade 3 HFS occurred in 4 pts (10%) with grade 3 myelosuppression in 1 pt (2%). AEs were mild and resolved in all pts. The overall response rate was 63%, including 5 CRs and 22 PRs. At a median follow-up of 6 months, median PFS has not been reached. Conclusions: The combination of H and X is a highly active and well-tolerated regimen for first-line treatment of HER2-positive MBC. Updated data will be presented.

No significant financial relationships to disclose.

A pilot study of weekly versus 3-week docetaxel in combination with capecitabine in patients with anthracycline-pretreated metastatic breast cancer

10771

Background: Capecitabine in combination with docetaxel given every 3 weeks has shown a high degree of activity in anthracycline-pretreated metastatic breast cancer (MBC), but with high toxicities. To improve the therapeutic index, we performed a clinical pilot trial to evaluate the efficacy and safety of weekly or 3-week docetaxel in combination with capecitabine given for 14 days every 21 days. Methods: Patients with at least one measurable lesion were randomized to receive the treatment arms: docetaxel 75mg/m2 on days 1, oral capecitabine 950 mg/m2 twice daily on days 1–14 (Arm A); docetaxel 37.5mg/m2 on days 1 and 8, oral capecitabine 950 mg/m2 twice daily on days 1–14 (arm B). Each cycle was repeated every 3 weeks. Patients remained on study for a maximum 6 cycles or until tumor progression or unacceptable toxicity occurred, response assessments were scheduled every two cycles. Results: 64 pts were enrolled, 62 eligible for safety and tumor assessment. Key baseline variables were well balanced. Dominant site of disease was visceral in 66.1%; 24.2% had ≥3 organ sites of disease; all patients had previously received anthracyclines, 24.2% for MBC. 43. 6% were ER negative and 46.8% were HER-2 overexpress. The overall clinical response rate of all groups was 59.7% (37/62). There was no progressive disease (PD) after two cycles. Efficacy outcomes were similar in the two arms. The response rate of group A and B were 60% (18/30) and 59.4% (19/32) respectively. There were no drug-related deaths observed. Neutropenia was the most common toxicity. In all, the frequence of Grade 3/4 neutropenia were similar in two arm, but Grade 4 neutropenia of Group A 66.7% (20/30) was higher than Group B 34.4% (11/32), P = 0.021. Conclusions: The study confirmed the superior activity of docetaxe-capecitabine combination therapy in anthracycline resistant MBC, and comparing with 3-week schedule, weekly docetaxel plus capecitabine has same high efficacy with a favourable safety profile.

No significant financial relationships to disclose.

Co-transplantation of plasmid-transfected myoblasts and myotubes into rat brains enables high levels of gene expression long-term

We have previously proposed the use of primary muscle cells as a "platform," or "vehicle" for intracerebral transgene expression. Brain grafts of minced muscle, or cultured muscle cells persisted in rat brains for at least 6 mo without any decrease in graft size, or tumor formation. Stable, but moderate levels of intracerebral transgene expression were obtained by transplanting plasmid-transfected myotubes in culture. In the present study, high and stable levels of intracerebral transgene expression were achieved by the co-transplantation of plasmid-transfected myoblasts and myotubes in culture. Approximately 5 X 10(5) myoblasts and myotubes were transfected with 10 micrograms pRSVL plasmid DNA, and 30 micrograms Lipofectin (BRL), respectively. They were mixed together (total cell number was 1 million), and stereotactically injected into the caudate nucleus of an adult rat brain. The activity of luciferase, the product of transgene expression, was stable for at least 4 mo, and much higher than the levels in myotube grafts, or co-grafts of myoblasts and minced muscle. Presumably, the myotubes served as a framework on which the myoblasts can form myotubes. The sections of brains transplanted with co-graft of myoblasts, and myotubes transfected with pRSVLac-Z were stained immunofluorescently for beta-galactosidase activity. The muscle grafts contained beta-galactosidase positive myofibers 4 mo after transplantation. Such high and stable levels of in vivo expression after postnatal gene transfer have rarely been achieved. Primary muscle cells are useful vehicle for transgene expression in brains, and potentially valuable for gene therapy of degenerative neurological disorders.

Heat-stress induced synthesis of chloroplast protein synthesis elongation factor (EF-Tu) in a heat-tolerant maize line

A heat-tolerant maize (Zea mays L.) line, ZPBL 1304, synthesizes a unique set of five heat-shock polypeptides of 45 kDa. Previous studies suggested that these polypeptides might play a role in the development of thermotolerance in maize (Ristic et al., 1996, J. Plant Physiol. 149:424-432; Ristic et al., 1998, J. Plant Physiol. 153:497-505). In the present study, we isolated these polypeptides, sequenced them, and investigated their subcellular distribution and origin. Of the five polypeptides of 45 kDa, three polypeptides, including the two most abundant ones, yielded amino acid sequences similar to the chloroplast and bacterial protein synthesis elongation factor (EF-Tu). This was further confirmed using an antibody raised against maize EF-Tu, which showed a very strong reaction with the 45-kDa heatshock protein(s). Studies on subcellular distribution and origin revealed that the 45-kDa polypeptides were localized to the chloroplasts, and were likely of nuclear origin. A full-length maize EF-Tu cDNA (Zmeftu1), previously isolated from the B73 line of maize, was used as a probe for northern blot analysis of RNA extracted from the ZPBL 1304 maize line (the nucleotide and deduced amino acid sequences of Zmeftu1 are 88% identical to the rice EF-Tu sequence). Northern blots showed a 1.85-fold increase in steady-state levels of EF-Tu mRNA during heat stress. An increase in EF-Tu transcript levels during heat stress was accompanied by increased levels of the EF-Tu protein. Isolated chloroplasts from heat-stressed plants also had higher levels of EF-Tu as compared to control chloroplasts. The maize EF-Tu polypeptides showed > 80% sequence similarity with the bacterial EF-Tu, which has recently been shown to function as a molecular chaperone and to play a role in the protection of other proteins from thermal denaturation (Caldas et al., 1998, J. Biol. Chem. 273:11478-11482). It is hypothesized that chloroplast EF-Tu of the ZPBL 1304 maize line plays an important role in the development of thermotolerance.

[Clinical significance of CD44 expression in ovarian epithelial tumors]

OBJECTIVE

To study the clinical significance of the adhesion molecule CD44 expression in ovarian epithelial tumors and its relation to the clinical manifestation of ovarian cancer.

METHODS

The expression of CD44 protein and mRNA was examined by immunohistochemistry, RT-PCR, nested PCR and densitometric scanning. The correlation between CD44 expression and clinicopathological features was analyzed.

RESULTS

In comparison with benign ovarian tumors, CD44H protein expression was significantly higher in ovarian cancer in terms of positive rate as well as the level of expression. The levels of mRNA expression in ovarian cancer positively correlated with the grade and stage. The CD44H mRNA expression level in primary tumor correlated with that in the metastatic lesions. High levels of expression of CD44H mRNA predicted poor survival probability. The expression rate of CD44V3, CD44V4/5 and CD44V6 protein was 21.2%, 19.2% and 15.4% respectively in ovarian cancer as compared to 3.1%, 12.5% and 0 in benign tumors. There was significant difference between the two groups in CD44V6.

CONCLUSION

Epithelial carcinoma of ovary expresses high level of CD44H. The amount of CD44H mRNA expression increased with progression of ovarian cancer. It can serve as a predictor of prognosis. It may play an important role in the peritoneal dissemination of ovarian cancer. Expression of CD44V6 is characteristic of malignant ovarian epithelial tumor.

Depth-resolved two-dimensional stokes vectors of backscattered light and mueller matrices of biological tissue measured with optical coherence tomography

Mueller matrices provide a complete characterization of the optical polarization properties of biological tissue. A polarization-sensitive optical coherence tomography (OCT) system was built and used to investigate the optical polarization properties of biological tissues and other turbid media. The apparent degree of polarization (DOP) of the backscattered light was measured with both liquid and solid scattering samples. The DOP maintains the value of unity within the detectable depth for the solid sample, whereas the DOP decreases with the optical depth for the liquid sample. Two-dimensional depth-resolved images of both the Stokes vectors of the backscattered light and the full Mueller matrices of biological tissue were measured with this system. These polarization measurements revealed some tissue structures that are not perceptible with standard OCT.

Frequency-swept ultrasound-modulated optical tomography in biological tissue by use of parallel detection

A frequency-swept ultrasonic beam was focused into a biological tissue sample to modulate the laser light passing through the ultrasonic beam inside the tissue. Parallel detection of the speckle field formed by the transmitted laser light was implemented with the source-synchronous-illumination lock-in technique to improve the signal-to-noise ratio. The ultrasound-modulated laser light reflects the local optical and mechanical properties in the ultrasonic beam and can be used for tomographic imaging of the tissue. Sweeping the ultrasonic frequency provides spatial resolution along the ultrasonic axis, which is scalable with the frequency span of the sweep. Two-dimensional images of biological tissue with buried objects were successfully obtained experimentally.

Effect of Q-switched alexandrite laser irradiation on dermal melanocytes of nevus of Ota

OBJECTIVE

To investigate the effect of Q-switched alexandrite laser irradiation on dermal melanocytes of nevus of Ota.

METHODS

Multiple biopsies were carried out on 4 patients with nevus of Ota before and after laser irradiation. Altogether 11 samples were examined under light microscope and 14 under transmission electron microscope.

RESULTS

Immediately after laser irradiation, the dermal melanocytes were destroyed, the melanosomes were degenerated with central vesicle formation within most of them, and intradermal round vacuoles appeared. The epidermis remained intact. Three months to 1 year after irradiation, the degenerated melanosomes and cell debris were scavenged mainly by macrophages. Dermal melanocytes gradually decreased. No fibrosis was found.

CONCLUSION

Q-switched alexandrite laser can selectively destroy dermal melanocytes of nevus of Ota and treat the disease safely.

DNA content and differentiation of root apical cells of Brassica rapa plants grown in microgravity

Root cap is proposed to be a graviperceptive tissue in the plant root, and it is composed of several cell types. One such cell type, the columella cells, are thought to initiate the gravity-induced signal transduction cascade, and these cells arise from the activity of the meristematic zone of the root cap. There is, in fact, a continuum of cells in the central column of the root cap representing the meristematic cells, developing columella cells, mature cells, and those that will soon be sloughed off into the soil. In order to study the functional roles of the root cap cells in gravity-sensing, we compared the ultrastructural organization, differentiation, and DNA content in the meristematic, elongating, and differentiating cells of root tips in Brassica rapa plants grown in space microgravity and at 1g. The experiments were also designed to determine the reactions of root cap cells in both main roots (in which the original root cap was present in an embryonic form within the seed) and lateral roots (in which the root cap formed completely in space after seed germination on orbit) to the space microgravity. This study (ROOTS) was performed in collaboration with the B-PAC experiment on the Space shuttle "Columbia" mission STS-87 (Collaborative US/Ukrainian Experiment (CUE) during November 19-December 5, 1997.