An expression profiling analysis of hybrid millet and its parents at grain filling stage

Heterosis has been widely used in crop breeding and production. However, a shortage of genes known to function in heterosis significantly limits our understanding of the molecular basis underlying heterosis. Here, we report 740 differentially expressed genes (DEGs) in the leaves of the hybrid millet Zhang No.5 and its parents at the grain filling stage determined using Solexa Illumina digital gene expression. Of the 740 DEGs, 546 were from the hybrid and its parents and most were up-regulated in the hybrid. Particularly, a large number of DEGs related to starch and carbohydrate metabolism and 2 DEGs encoding chlorophyll a/b binding proteins were up-regulated in hybrid millet. Moreover, all DEGs were enriched in the biological process and molecular function, and no DEGs were found to be enriched in the cellular component of GO terms. Pathway enrichment using KEGG showed that several DEGs were enriched in the circadian rhythm pathway. Further analysis revealed that the altered circadian rhythm, which mediates photosynthesis and carbohydrate accumulation, may play an important role in heterosis of the hybrid millet.

KIF14 promotes AKT phosphorylation and contributes to chemoresistance in triple-negative breast cancer

Despite evidence that kinesin family member 14 (KIF14) can serve as a prognostic biomarker in various solid tumors, how it contributes to tumorigenesis remains unclear. We observed that experimental decrease in KIF14 expression increases docetaxel chemosensitivity in estrogen receptor-negative/progesterone receptor-negative/human epidermal growth factor receptor 2-negative, "triple-negative" breast cancers (TNBC). To investigate the oncogenic role of KIF14, we used noncancerous human mammary epithelial cells and ectopically expressed KIF14 and found increased proliferative capacity, increased anchorage-independent grown in vitro, and increased resistance to docetaxel but not to doxorubicin, carboplatin, or gemcitabine. Seventeen benign breast biopsies of BRCA1 or BRCA2 mutation carriers showed increased KIF14 mRNA expression by fluorescence in situ hybridization compared to controls with no known mutations in BRCA1 or BRCA2, suggesting increased KIF14 expression as a biomarker of high-risk breast tissue. Evaluation of 34 cases of locally advanced TNBC showed that KIF14 expression significantly correlates with chemotherapy-resistant breast cancer. KIF14 knockdown also correlates with decreased AKT phosphorylation and activity. Live-cell imaging confirmed an insulin-induced temporal colocalization of KIF14 and AKT at the plasma membrane, suggesting a potential role of KIF14 in promoting activation of AKT. An experimental small-molecule inhibitor of KIF14 was then used to evaluate the potential anticancer benefits of downregulating KIF14 activity. Inhibition of KIF14 shows a chemosensitizing effect and correlates with decreasing activation of AKT. Together, these findings show an early and critical role for KIF14 in the tumorigenic potential of TNBC, and therapeutic targeting of KIF14 is feasible and effective for TNBC.

Cloning and sequence analysis of sucrose phosphate synthase gene from varieties of Pennisetum species

Sucrose phosphate synthase (SPS) is an enzyme used by higher plants for sucrose synthesis. In this study, three primer sets were designed on the basis of known SPS sequences from maize (GenBank: NM_001112224.1) and sugarcane (GenBank: JN584485.1), and five novel SPS genes were identified by RT-PCR from the genomes of Pennisetum spp (the hybrid P. americanum x P. purpureum, P. purpureum Schum., P. purpureum Schum. cv. Red, P. purpureum Schum. cv. Taiwan, and P. purpureum Schum. cv. Mott). The cloned sequences showed 99.9% identity and 80-88% similarity to the SPS sequences of other plants. The SPS gene of hybrid Pennisetum had one nucleotide and four amino acid polymorphisms compared to the other four germplasms, and cluster analysis was performed to assess genetic diversity in this species. Additional characterization of the SPS gene product can potentially allow Pennisetum to be exploited as a biofuel source.

Overregulation of microRNA-212 in the poor prognosis of esophageal cancer patients

There have been few reports evaluating the expression and function of the microRNA miR-212 in esophageal cancer. The aim of this study was to investigate the relationship between miR-212 expression and clinicopathological factors and prognoses of esophageal cancer. MicroRNA was extracted from 46 esophageal cancer patients using the Taqman MicroRNA assay. All patients were at the same tumor node metastasis stage, but with different prognoses, and had all undergone surgery. The correlation between miR-212 expression and clinicopathological features was analyzed and the significance of miR-212 as a prognostic factor as well as its relationship with survival was determined. miR-212 expression was higher in patients with poor prognoses than in those with good prognoses (P < 0.0001). Kaplan-Meier analysis results showed that the miR-212 expression level was significantly correlated with survival time (P = 0.024). Patients with higher expression of miR-212 showed longer survival times. Cox multi-factor model analysis showed that miR-212 expression was significantly correlated with survival time (P = 0.026). mir-212 is related with prognostic factors and survival time and may be a biomarker for esophageal cancer.

Characteristics of unrecognised bipolar disorder in patients treated for major depressive disorder in China: general versus psychiatric hospitals

OBJECTIVES

Bipolar disorder is often misdiagnosed as major depressive disorder. Such misdiagnosis partly depends on the type of treatment setting. This study compared general hospital psychiatric units with psychiatric hospitals in China with respect to basic demographic and clinical characteristics of patients with unrecognised bipolar disorder who are treated for major depressive disorder.

METHODS

Patients treated for major depressive disorder were consecutively examined in 13 health centres (6 general hospital psychiatric units and 7 psychiatric hospitals) in China. Their socio-demographic and clinical features were recorded using a standardised protocol and data collection procedure. The DSM-IV diagnoses were established using the Mini-International Neuropsychiatric Interview.

RESULTS

Of the 1487 patients included in the study, 309 (20.8%) were diagnosed with bipolar disorder. There was no significant difference between general hospital psychiatric units and psychiatric hospitals in the ratio of all types of unrecognised bipolar disorders (χ2 = 0.008, degrees of freedom = 1, p = 0.9) and bipolar II disorders (χ2 = 3.1, degrees of freedom = 1, p = 0.08). The proportions of unrecognised bipolar I disorders (χ2 = 4.1, degrees of freedom = 1, p = 0.04) differed significantly between the 2 types of study site. Multivariate analyses showed that patients with bipolar I disorders with more seasonal depressive episodes were more likely to receive treatment in general hospital psychiatric units (odds ratio = 3.3, 95% confidence interval = 1.1-9.8).

CONCLUSION

Patients with bipolar I disorders receiving treatment in general hospital psychiatric units had different clinical characteristics compared to their counterparts treated in psychiatric hospitals in China.

Influence of fluoride additions on biological and mechanical properties of Na2O-CaO-SiO2-P2O5 glass-ceramics

Two series of Na2O-CaO-SiO2-P2O5 glass-ceramics doped with NH4HF2 (G-NH4HF2) or CaF2 (G-CaF2) have been prepared by sol-gel method. The glass-ceramic phase composition and morphology were characterized by X-ray diffraction (XRD) and scanning electron microscopy coupled with energy dispersive spectroscopy (SEM-EDS). The mechanical properties and thermal expansion coefficient were measured by a microhardness tester, an electronic tensile machine and a thermal expansion coefficient tester. The structure difference between these two glass-ceramics was investigated by Fourier transform infrared spectroscopy (FTIR), and the in vitro bioactivity of the glass-ceramics was determined by in vitro simulated body fluid (SBF) immersion test. The hemolysis test, in vitro cytotoxicity test, systemic toxicity test and the implanted experiment in animals were used to evaluate the biocompatibility of the glass-ceramics. The mechanical properties of sample G-NH4HF2 are lower than that of sample G-CaF2, and the bioactivity of sample G-NH4HF2 is better than that of sample G-CaF2. The thermal expansion coefficients of these two glass-ceramics are all closer to that of Ti6Al4V. After 7 days of SBF immersion, apatites were induced on glass-ceramic surface, indicating that the glass-ceramics have bioactivity. The hemolysis test, in vitro cytotoxicity test and systemic toxicity test demonstrate that the glass-ceramics do not cause hemolysis reaction, and have no toxicity to cell and living animal. The implanted experiment in animals shows that bone tissue can form a good osseointegration with the implant after implantation for two months, indicating that the glass-ceramics are safe to serve as implants.

Abstract P4-11-08: A Pilot Safety and Feasibility Study of Concurrent Capecitabine and External Beam Irradiation in the Adjuvant Treatment of High Risk Early Stage Breast Cancer

Background: Capecitabine (Xeloda ®) is an oral 5-FU pro-drug that is preferentially converted to the active form 5-FU within tumor tissue, offering many of the same benefits of continuous 5-FU infusion with the convenience of oral delivery. In studies of patients receiving chemotherapy with or without radiation therapy, combination therapy has proved more efficacious than either modality alone. If radiation therapy can more effectively eliminate local microscopic residual disease, this will resultin improved local control and may potentially increase overall survival. This phase II study was performed to ascertain the safety and feasibility of capecitabine concurrent with radiation therapy in high risk non-metastatic breast cancer.

Materials and methods: Eligible patients had undergone surgery and chemotherapy for high risk breast cancer, defined for this study as either a T3 or T4 primary tumor, or N2 (≥4 nodes involved) or greater nodal status. Capecitabine was administered at 825 mg/m2 twice daily on days of radiotherapy. The primary endpoint of this study was toxicity, scored using CTCAE v 3.0, evaluated during therapy and in follow-up at intervals up to 12 months. Clinically significant toxicities were defined as skin toxicity or hematological toxicity of grade 3 or greater, or other toxicity felt related to capecitabine of grade 2 or greater. Feasibility was defined as percent of patients completing the course of drug, and the percent of patients completing radiation therapy to a dose of at least 50.4 Gy. Cosmesis was rated by the physician and the patient separately.

Results: 50 women were enrolled in this study; the mean age was 52 (range 33-77). T stage distribution was as follows: T0 4%, T1 16%, T2 50%, T3 18%, and T4 12%. N stage N0 6%, N1 18%, N2 44%, and N3 32%. Mean number of pathologically involved nodes was 8 (range 0-36); 56 % of patients were treated with neoadjuvant chemotherapy prior to definitive surgery, which for 84% was mastectomy. Four patients withdrew prior to starting or within the first week; of the remaining 46 patients, 10 had capecitabine discontinued or dose-reduced, and one patient died during treatment. Those patients who did not receive the full drug dose had on average 3.8 weeks of capecitabine therapy; of the overall 46 patients, 76 % received the intended dose of drug throughout the radiation treatments; 98% of patients received at least 50.4 Gy. Toxicities observed included 7 pts with grade 3 radiation dermatitis, 3 with grade 3 hand-foot syndrome, 1 with grade 4 diarrhea, and 1 with grade 5 cardiac arrest felt possibly related to capecitabine; 2 other grade 3 toxicities (range of motion limitation and bone pain) were felt not related to the study. Mean cosmesis scores at baseline were assessed to be “good” by both patients and physicians; these were stable at 12 months of follow-up. 90 % of patients were alive at 12 months, and 2 (4 %) were observed to suffer local, in-field failure. Discussion: Radiation therapy in combination with capecitabine is a well tolerated adjuvant therapy for patients with high risk breast cancer, with most patients completing all therapy. Controlled studies examining efficacy are warranted.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P4-11-08.

Measurement and receptor modeling of atmospheric polycyclic aromatic hydrocarbons in urban Kaohsiung, Taiwan

The concentrations of 21 individual polycyclic aromatic hydrocarbons (PAHs) and total suspended particles (TSPs) were measured using high-volume air samplers at Tzuo-Yin and Hsiung-Kong sites in Kaohsiung City, Taiwan, for four seasons from 2005 to 2006. The gaseous and particulate phases of individual PAHs were identified using a gas chromatograph with a flame-ionization detector (GC/FID). Measurements show that the concentrations of total (gas+particulate) PAHs generally followed the seasonal variations of the concentrations of TSP (107.2-117.1 microg m(-3)), being the highest in winter (143.9-182.9 ng m(-3)) and lowest in summer (81.4-95.2 ng m(-3)) at both sites. Most PAH species were low-weight PAHs (approximately 80.8-82.0%), followed by high-weight PAHs (10.5-14.6%) and medium-weight PAHs (6.5-6.8%). The fractions of gaseous PAHs decreased with molecular weight or ring number. The particle phase (60.2(73.5%) dominated the high-weight PAHs. Results of receptor model show that industrial combustions (49.1-63.7%) contributed most to ambient PAHs, followed by restaurant emissions (18.4-39.7%) and mobile sources (11.3-22.8%) at the Tzuo-Yin site. At the Hsiung-Kong, mobile sources (49.5-63.3%) contributed most to ambient PAHs, followed by restaurant emissions (19.8-36.6%) and industrial combustions (13.7-27.1%). The differences in the results at the two sites are mainly attributed to the different industries at each site.

Metastatic rectal cancer to the breast

Rectal cancer metastatic to the breast is an exceedingly rare event with around 15 cases reported in the literature. A metastatic breast deposit from the rectum signifies diffuse disseminated disease or a highly aggressive tumor such that surgical intervention other than palliation has a limited role. In the present report, we discuss a patient who presented with rectal cancer and developed a breast metastatic deposit. She soon developed progressive metastatic involvement of the lungs and the soft tissues and succumbed to the malignant course of this disease 12 months after the diagnosis of the primary rectal tumor.

Absence of association between two insertion/deletion coding genetic polymorphisms of TIM-1 gene and asthma in Chinese Han population

TIM-1, a member of T-cell immunoglobulin domain and mucin domain (TIM) gene family, was implicated as an asthma susceptibility gene in previous studies. TIM-1 was expressed on CD4(+) T cells after activation and its expression was sustained preferentially in T-helper type 2 (T(H)2) but not in T(H)1 cells, therefore TIM-1 became a good candidate gene for atopic diseases. Recent studies indicated that two insertion/deletion (ins/del) coding genetic polymorphisms in exon 4 of TIM-1 were associated with asthma susceptibility in some but not in all populations. In order to investigate the relationship between TIM-1 genetic polymorphisms and asthma in Chinese Han population, we performed a case-control study for two insertion/deletion polymorphisms in TIM-1 exon 4 (5383_5397ins/del and 5509_5511delCAA) and a single nucleotide polymorphism (SNP) in intron 8 (IVS 8+9 G/A) between a healthy control group of 309 people and an asthma patient group of 352 people recruited from Chinese Han population. The polymorphisms were genotyped and the allele and genotype frequencies were analysed, but none of the three polymorphisms showed association with asthma susceptibility in single-locus association analyses. Linkage disequilibrium (LD) analyses demonstrated that the two insertion/deletion polymorphisms were in strong LD but the haplotypes constructed from these two polymorphisms showed no significant association with asthma. In conclusion, our findings suggest that 5383_5397ins/del, 5509_5511delCAA and SNP IVS 8+9 G/A polymorphisms are not associated with asthma susceptibility in Chinese Han population.

Lack of association between ADAM33 gene and asthma in a Chinese population

Asthma is a complex polygenic disease with gene-environment interactions being important. It has been previously suggested that ADAM33, which is a member of a gene family that encodes membrane-anchored proteins with a disintegrin and a metalloprotease domain, is primarily expressed in lung fibroblasts and bronchial smooth muscle cells and has been associated with airway remodelling and bronchial hyperresponsiveness. A significant association has previously been demonstrated between single nucleotide polymorphisms (SNPs) and haplotypes of the ADAM33 and asthma in ethnically diverse populations. To assess whether SNPs or haplotypes of ADAM33 are related to asthma in a Chinese Han population, we genotyped three SNPs of ADAM33 (7575G/A in intron 6, 11188A/T in intron 19, and 12433T/C in exon 20) in a case-control study involving 296 patients with asthma and 270 healthy controls. No significant association was detected between these three SNPs and asthma susceptibility in the Chinese population.

Over expression of aromatase protein is highly related to MMPs levels in human breast carcinomas

Estrogens can play a critical role in the development of breast cancer. Aromatase which catalyzes the formation of aromatic C18 estrogens from C19 androgens is regarded to be responsible for the cancer local production of estrogen. Studies not only from aromatase transfected breast cancer cells, but also transgenic mouse, which overexpressed aromatase, demonstrated that in situ produced estrogen plays more important roles than circulating estrogens in breast tumor promotion and progression. Matrix-metalloproteinases (MMPs) have been implicated in the proeolytic process, which play important roles in the aggressiveness of cancer cells including invasion of adjacent tissue and metastasis to distant sites. Expression of MMP2 and 9 may be stimulated by estrogens in hormonal dependent breast cancers, since tumor aromatase can stimulate breast cancer growth and progression in both an autocrine and a paracrine manner. Theoretically aromatase overexpression, that causes relatively high estrogen concentration in situ, may be positively related to MMP2 and 9 expression, indicate worse prognosis in breast cancers, and maybe insensitive to tamoxifen therapy. In the present study, we studied the expression of aromatase activity and MMPs in human breast carcinoma both in vitro and in vivo. In human breast carcinoma cell lines including MCF-7, MDA-MB-231 and MDA-MB-435, the expression of aromatase levels both in mRNA and protein activity was related to MMP2 and MMP9. In humam breast cancer samples, we demonstrated that aromatase expressions were strongly associated with MMP2 and MMP9 levels. It was interesting to observe that the positive relationship was only present in the ER and/or PR positive patients. This may indicate that both MMP2 and MMP9 were up regulated by estrogen produced by aromatase through ER. So in endocrine therapy, either blocking the ER by tamoxifen or inhibiting the aromatase by aromatase inhibitors for example letrozole, may both inhibit tumor growth and lower the metastatic potential especially in ER positive breast cancer patients by means of down-regulation of MMP2/9.

Gemcitabine and platinum-based chemotherapy in metastatic breast cancer

Although anthracyclines and the taxanes comprise the most active first-line cytotoxic treatments in patients with hormone-insensitive or life-threatening metastatic breast cancer, many patients progress and require other chemotherapeutic agents. Development of new combinations and/or agents is thus needed. Gemcitabine (Gemzar) and platinum compounds have been employed as single agents, and the addition of gemcitabine to the platinums results in significant clinical benefit and response rates. Correlative biologic studies are expected from several already-reported trials and may help elucidate predictive factors for both response and toxicity when combining gemcitabine and the platinums. Trials incorporating these doublets in earlier stages of breast cancer or in the neoadjuvant setting may further elucidate their role in breast cancer treatment.

Feasibility of a partial meal replacement plan for weight loss in low-income patients

BACKGROUND

Low-income patients are disproportionately affected by obesity. Routine care is available to this population at the Venice Family Clinic (VFC) in Los Angeles. The current study examined the effectiveness of nutrition clinic utilizing meal replacements (Slim-Fast, Slim-Fast Foods Co., FL, USA) in low-income patients over a 6-month period compared with the routine care by their primary care physician (PMD) prior to enrolling in the nutrition clinic at similar time intervals.

METHODS

In total, 63 patients (51 F; 49+/-0.8 yo) who had been followed at the VFC by their PMD for at least 6 months were enrolled in this study. Patients had a body mass index (BMI) of 40+/-1.1 kg/m2, were 72% Hispanic, 25% Caucasian, and 3% African American. They had the following co-morbidities: hypertension (HTN) 45%, diabetes mellitus II (DM II) 50%, gastroesophageal reflux disease (GERD) 34%, osteoarthritis 51%, and hypercholesterolemia 48%. All patients were provided with meal replacements to be taken twice a day and were instructed to consume one complete low calorie meal per day. Weights at the first visit to the nutrition clinic, 1, 3, and 6 months after enrollment in nutrition clinic were compared to their weights at the same time intervals during routine visits to their PMD prior to enrollment in the nutrition clinic.

RESULTS

There was no significant weight change during the 6 months prior to enrollment in the nutrition program despite receiving care by a PMD. At 6 months after participating in the nutrition program, there was a mean decrease of 7% body weight with a reduction in BMI from 40-37 kg/m2 (P< or =0.05).

CONCLUSION

Implementation of nutrition clinic utilizing meal replacements in this low-income patient population was effective in achieving a significant reduction in weight over 6 months of treatment..

Motion-surface labeling by orientation, spatial frequency and luminance polarity in 3-D structure-from-motion

A compelling percept of three-dimensionality is attainable from a purely motion-defined simulation of a transparent rotating cylinder, referred to as 3-D structure-from-motion (SFM). Interestingly, subjects rarely perceive reversals of the cylinder's direction of rotation when they are introduced. Treue, Andersen, Ando, and Hildreth (Vision Res. 35 (1995) 139-148) have argued that this reflects the visual system's insensitivity to the textural detail on the cylinder's motion surfaces. We have recently shown however that with cylinders made from oriented micropatterns, motion reversals are perceived when the orientations of the micropatterns are different on the cylinder's front/back surfaces, suggesting that the visual system is sensitive to the type of feature in these stimuli (Vision Res. 39 (1999) 881-886). In the present study we extended this finding by testing for feature-sensitivity along other dimensions besides orientation, specifically spatial frequency, colour and luminance polarity. We found that subjects perceived more rotation direction reversals when the front/back surfaces of the cylinder were segregated, as opposed to non-segregated by feature-type, along all of these dimensions except, notably, colour. We also investigated the stage at which the feature-sensitivity is incorporated in 3-D SFM. We reasoned that if 3-D SFM mechanisms were tuned, or labeled for feature-type, swapping of features during the cylinder's rotation would result in illusory reversals in just the feature-segregated condition, whereas if grouping of like-features preceded the formation of 3-D motion surfaces, no such illusory reversals would be expected. We found that feature-swapping resulted in more illusory reversals in the feature-segregated compared to non-segregated conditions, supporting the mechanism tuning, or labeling, hypothesis.

Restriction of proliferation of primordial germ cells by the irradiation of Japanese quail embryos with soft X-rays

Primordial germ cells (PGCs) are the progenitor cells for the gametes. Avian PGCs are located in the central region of the area pellucida at the blastoderm stage. Shortly after further incubation, they migrate to the extra-embryonic germinal crescent, and then as soon as the blood vessels form, they enter the circulation and finally settle in the gonadal primordium. We have developed a simple method using soft X-ray irradiation (18 kV power, 20 cm distance) to reduce the number of PGCs in Japanese quail embryos, which should be useful in preparing recipient embryos for PGC-transfer studies. When embryos were exposed to the soft X-rays for 40 s before incubation, the concentration of circulating PGCs was less than one-fifth that in controls after 2 days of incubation. Embryos at day 6 of incubation contained approximately half the number of PGCs compared to controls when they were exposed before or at day 2 of incubation. Irradiation for 40 s is recommended taking into consideration the restriction of proliferation of PGCs, and viability and hatchability.

Stimulation of tumor growth by human soluble intercellular adhesion molecule-1

Because serum levels of soluble intercellular adhesion molecule-1 (sICAM-1) are elevated in cancer and sICAM-1 is angiogenic, we tested the ability of sICAM-1 to promote tumor growth. Our preliminary experiments showed that exogenous sICAM-1 significantly stimulated the growth of human tumors in vivo. Human fibrosarcoma transfectants, which express ICAM-1, produce ICAM-1 on the cell surface and release sICAM-1 into the medium without any apparent effect on cell growth in vitro. We found that conditioned medium from sense ICAM-1 transfectants compared with mock or antisense ICAM-1 transfectants stimulates endothelial cell migration in vitro and neovascularization in the chick chorioallantoic membrane assay. Tumor cells transfected with sense constructs form faster growing tumors than mock- and antisense-transfected cells in both chick embryos and nude mice models. Serum levels of human sICAM-1 from nude mice bearing sense ICAM-1 transfectants correlate positively with tumor weight. Sense ICAM-1 transfectants are more proliferative and induce more blood vessel formation than mock and antisense transfectants in nude mice. Because expression of ICAM-1 does not affect tumor cell growth in vitro, the angiogenic activity of sICAM-1 produced by sense ICAM-1 transfectants may be involved in the stimulation of tumor growth. Therefore, sICAM-1 may perform dual functions that are essential for tumor growth: angiogenesis and escape from immune surveillance.

Segregation by color/luminance does not necessarily facilitate motion discrimination in the presence of motion distractors

Under what circumstances is the common motion of a group of elements more easily perceived when the elements differ in color and/or luminance polarity from their surround? Croner and Albright (1997), using a conventional global motion paradigm, first showed that motion coherence thresholds fell when target and distractor elements were made different in color. However, in their paradigm, there was a cue in the static view of the stimulus as to which elements belonged to the target. Arguably, in order to determine whether the visual system automatically groups, or prefilters, the image into different color maps for motion processing, such static form cues should be eliminated. Using various arrangements of the global motion stimulus in which we eliminated all static form cues, we found that global motion thresholds were no better when target and distractors differed in color than when they were identical, except under certain circumstances in which subjects had prior knowledge of the specific target color. We conclude that, in the absence of either static form cues or the possibility of selective attention to the target color, features with similar colors/luminance-polarities are not automatically grouped for global motion analysis.

Transcriptional induction of hepatic NADPH: cytochrome P450 oxidoreductase by thyroid hormone

Studies were carried out to elucidate the mechanism whereby thyroid hormone (T3) induces NADPH:cytochrome P450 oxidoreductase (P450R) mRNA in rat liver in vivo. Northern blot analysis revealed that T3 treatment increases unspliced liver nuclear P450R RNA 4-fold within 8 h and that this induction precedes the induction of mature, cytoplasmic P450R RNA. Unspliced nuclear P450R RNA was suppressed below basal levels 24 h after T3 treatment, despite the continued presence of elevated circulating T3 levels. To determine whether the T3-stimulated increase in nuclear P450R RNA reflects an increase in P450R transcription initiation, nuclear run-on transcription assays were carried out. T3 induced a 6- to 8-fold increase in P450R transcription rate within 12 h, sufficient to account for the observed increase in nuclear P450R precursor RNA, followed by a decrease back to basal transcription levels at 24 h, consistent with the nuclear RNA profile. Similar transcriptional increases were observed in nuclear run-on transcription studies using hybridization probes corresponding to nine different fragments of the P450R gene, spanning exon 2 to exon 16. Thus, P450R transcription initiation, not transcription elongation, is the T3-regulated event. Similar results were obtained during short (5 min) compared with long (45 min) nuclear run-on transcription assays, suggesting that changes in nuclear RNA processing or regulated degradation do not contribute to the overall RNA induction. This finding was confirmed by the ability of the RNA polymerase inhibitor actinomycin D, administered in vivo, to block T3 induction of P450R transcriptional activity. We conclude that P450R transcription, rather than nuclear RNA processing or mRNA stabilization, is the primary mechanism whereby T3 induces hepatic P450R mRNA.

The role of chromatic contrast and luminance polarity in stereoscopic segmentation

We have investigated whether our ability to discriminate the stereoscopic depth of random-dot targets set amongst random-depth distractors is facilitated when target and distractors differ in particular combinations of colour and luminance polarity. For flat-plane targets, stereo-thresholds were found to be lower with a target-distractor colour/luminance difference, but only when that difference enabled the target elements to be identified in the monocular image, either by virtue of being less numerous than the distractors, or because the subject knew beforehand the target's colour/luminance. If neither of these conditions prevailed, stereoscopic thresholds were no different when target and distractors were segregated by colour/luminance than if they were not. For sine-wave disparity grating stimuli, in which subjects were required to discriminate the orientation of the depth corrugations, no advantage was found when target and distractors were segregated by colour/luminance under any condition. These results suggest that segregation by colour/luminance is only beneficial to the stereoscopic processing of random-element stimuli when the task can be performed by attending to a small number of target elements. A corollary to this conclusion is that stereopsis mechanisms do not automatically pre-filter the image into different colour/luminance maps.

Ancient HTLV type 1 provirus DNA of Andean mummy

The worldwide geographic and ethnic clustering of patients with diseases related to human T cell lymphotropic virus type 1 (HTLV-1) may be explained by the natural history of HTLV-1 infection. The genetic characteristics of indigenous people in the Andes are similar to those of the Japanese, and HTLV-1 is generally detected in both groups. To clarify the common origin of HTLV-1 in Asia and the Andes, we analyzed HTLV-1 provirus DNA from Andean mummies about 1500 years old. Two of 104 mummy bone marrow specimens yielded a band of human beta-globin gene DNA 110 base pairs in length, and one of these two produced bands of HTLV-1-pX (open reading frame encoding p(40x), p(27x)) and HTLV-1-LTR (long terminal repeat) gene DNA 159 base pairs and 157 base pairs in length, respectively. The nucleotide sequences of ancient HTLV-1-pX and HTLV-1-LTR clones isolated from mummy bone marrow were similar to those in contemporary Andeans and Japanese, although there was microheterogeneity in the sequences of some mummy DNA clones. This result provides evidence that HTLV-1 was carried with ancient Mongoloids to the Andes before the Colonial era. Analysis of ancient HTLV-1 sequences could be a useful tool for studying the history of human retroviral infection as well as human prehistoric migration.

Immunohistochemical localization of type I collagen, fibronectin and tenascin C during embryonic osteogenesis in the dentary of mandibles and tibias in rats

Type I collagen, fibronectin and tenascin C play an important role in regulating early osteoblast differentiation, but the temporal and spatial relationship of their localization during embryonic osteogenesis in vivo is notknown. The present study was designed to localize these three molecules in the dentary of mandibles and tibias in rat embryos using immunohistochemistry. Serial paraffin sections were cut and adjacent sections were processed for von Kossa staining or immunohistochemistry for type I collagen, fibronectin and tenascin C. In the dentary, tenascin C was localized within and around the mesenchymal cell condensation in embryos at 14 days in utero. The bone matrix at 15 days showed immunoreactivity for both type I collagen and fibronectin. The immunoreactivity of type I collagen was persistent, whereas that of fibronectin decreased with age of embryos. In tibias, tenascin C was localized in the perichondral mesenchymal tissue at 17 days. Immunoreactivity for type I collagen was persistent in the bone matrix, whereas the tibial bone showed little immunoreactivity for fibronectin at any embryonic age examined. The present study demonstrated characteristic localization of type I collagen, fibronectin and tenascin C during embryonic osteogenesis in the dentary of mandibles and tibias.

Mechanism of induction of rat hepatic CYP2B and 3A by the pesticide methoxychlor

Our earlier investigation demonstrated that methoxychlor treatment induced hepatic cytochrome P450 2B1/2B2 and 3A proteins in rats and enhanced their respective enzymatic activities. To determine the mechanism of the methoxychlor-mediated induction and whether methoxychlor acts as a frank inducer and not merely by causing stabilization of the cytochrome P450 proteins or of their mRNAs, we assessed the effect of methoxychlor treatment on the transcriptional rate and mRNA levels of these hemeproteins by nuclear run-on and northern blot analyses. Methoxychlor treatment markedly elevated the transcriptional rates of cytochrome P4502B1/2B2 and 3A. Also, higher levels of mRNA of these CYPs were observed. By contrast, mRNA levels of CYP1A1/1A2 were not affected. Using a nuclear run-on method that apparently measures specifically the transcription initiation rate of CYP2B1 and 2B2, we observed that the transcriptional rate of 2B2 was increased substantially more than that of CYP2B1. This differential induction of CYP2B2 versus 2B1 may account for the discrepancy between the levels of induced CYP2B protein and the much lower-than-expected CYP2B-mediated enzymatic activity observed in our earlier study.

Elevated expression and activity of protein-tyrosine phosphatase 1B in skeletal muscle of insulin-resistant type II diabetic Goto-Kakizaki rats

We investigated the cellular mechanism(s) of insulin resistance associated with non-insulin dependent diabetes mellitus (NIDDM) using skeletal muscles isolated from non-obese, insulin resistant type II diabetic Goto-Kakizaki (GK) rats, a well known genetic rat model for type II diabetic humans. Relative to non-diabetic control rats (WKY), insulin-stimulated insulin receptor (IR) autophosphorylation and insulin receptor substrate-1 (IRS-1) tyrosine phosphorylation were significantly inhibited in GK skeletal muscles. This may be due to increased dephosphorylation by a protein tyrosine phosphatase (PTPase). Therefore, we measured skeletal muscle total PTPase and PTPase 1B activities in the skeletal muscles isolated from control rats (WKY) and diabetic Goto-Kakizaki (GK) rats. PTPase activity was measured using a synthetic phosphopeptide, TRDIY(P)ETDY(P)Y(P)RK, as the substrate. Basal PTPase activity was 2-fold higher (P < 0.001) in skeletal muscle of GK rats when compared to WKY. Insulin infusion inhibited skeletal muscle PTPase activity in both control (26.20% of basal, P < 0.001) and GK (25.35% of basal, P < 0.001) rats. However, PTPase activity in skeletal muscle of insulin-stimulated GK rats was 200% higher than hormone-treated WKY controls (P < 0.001). Immunoprecipitation of PTPase 1B from skeletal muscle lysates and analysis of the enzyme activity in immunoprecipitates indicated that both basal and insulin-stimulated PTPase 1B activities were significantly higher (twofold, P < 0.001) in skeletal muscle of diabetic GK rats when compared to WKY controls. The increase in PTPase 1B activity in diabetic GK rats was associated with an increased expression of the PTPase 1B protein. We concluded that insulin resistance of GK rats is accompanied atleast by an abnormal regulation of PTPase 1B. Elevated PTPase 1B activity through enhanced tyrosine dephosphorylation of the insulin receptor and its substrates, may lead to impaired glucose tolerance and insulin resistance in GK rats.