Bone mineral density in midlife women: the Study of Women's Health in Qatar

OBJECTIVES

The aim of this study is to investigate bone mineral density (BMD) for a large cross-section of midlife Arab women living in Qatar and to evaluate the association of body mass index (BMI), menopause status, and nationality, on BMD of the spine and femur.

STUDY DESIGN

A cross-sectional study was conducted among women aged 40-60 years recruited from nine primary-care health centers in Qatar. BMD (g/m(2)) was assessed at the lumbar spine and the femur.

RESULTS

The combined prevalence of osteopenia and osteoporosis was 4% at the femur and 16.2% at the spine. BMI and menstrual status were both independently associated with BMD at the spine and at the femur (all p values < 0.001). As BMI increased, BMD increased at both the spine and femur. Women who menstruated in the past 12 months had 0.82 g/cm(2) and 0.61 g/cm(2) greater BMD at the spine and femur, respectively, compared with women who had not menstruated in 12 months. Nationality was not associated with mean BMD of the spine or the femur.

CONCLUSIONS

No significant differences were observed between Qatari and non-Qatari women in terms of mean BMD values at the spine and the femur except for the femur in the age group 55-60, where values were lower among non-Qataris (p = 0.04). Multivariable analyses showed that BMI and menstrual status were found to be strongly associated with BMD levels at the spine and femur. The high prevalence of obesity observed in this sample may explain the low levels of osteopenia and osteoporosis observed.

The resveratrol attenuates ethanol-induced hepatocyte apoptosis via inhibiting ER-related caspase-12 activation and PDE activity in vitro

BACKGROUND

Endoplasmic reticulum (ER) stress plays a key role in cell apoptosis pathways. Caspase-12, a proapoptotic gene induced by ER stress, is also the key molecule in ER-related apoptosis. The purpose of this study is to evaluate the protective activity and possible mechanism of resveratrol (ResV) against ethanol (EtOH)-induced apoptosis in human hepatocyte Chang cell line.

METHODS

The human hepatocyte Chang cell line was used to test the hypothesis that ResV may alleviate the liver cell apoptosis induced by EtOH. ER stress-inducible proteins and silent mating type information regulation 2 homolog 1 (SIRT1) were assayed by Western blot. Cell viability was studied by MTT assay and apoptosis was measured by Annexin-V and propidium iodide assay. Caspase-12 activation was examined by immunofluorescence staining. Alcohol dehydrogenase-2 (ADH-2) and aldehyde dehydrogenase-2 (ALDH-2) were measured by polymerase chain reaction amplified product length polymorphism. Phosphodiesterase (PDE) activity was assayed in cell lysates using a cyclic nucleotide PDE assay.

RESULTS

EtOH exposure significantly increased the expression of ER stress markers and activated signaling pathways associated with ER stress. These include GRP78, p-IRE1α, p-eIF2α, p-PERK, ATF4 as well as cleaved caspase-3/12, CHOP/GADD153, and Bax in human hepatocyte Chang cell line. The expression of these proteins were significantly down-regulated by ResV (10 μM) in a SIRT1-dependent manner. ResV can inhibit EtOH-, tunicamycin-, thapsigargin-induced caspase-12 activation. ADH-2 and ALDH-2 activities are lower in this cell line. PDE activity increased by EtOH was inhibited by ResV (10 μM).

CONCLUSIONS

The results indicate that (i) EtOH-induced activation of caspase-12 could be one of the underlying mechanisms of hepatocyte apoptosis; (ii) EtOH-induced cell apoptosis was alleviated via ResV (10 μM) by inhibiting ER stress and caspase-12 activation in a SIRT1-dependent manner; and (iii) SIRT1 activated indirectly by ResV (10 μM) attenuates EtOH-induced hepatocyte apoptosis partly through inhibiting PDE activity.

Association between lumican gene -1554 T/C polymorphism and high myopia in Asian population: a meta-analysis

AIM

To investigate the association between lumican gene -1554 T/C polymorphism and high myopia susceptibility.

METHODS

We searched the published literature in the Medline, Embase, and CBM databases from inception to July 2013. A meta-analysis was performed by the programs RevMan 5.1 and Stata 12.0, and the odds ratio (OR) with 95% confidence interval (CI) was calculated in fixed or random effect model based on heterogeneity test among studies.

RESLUTS

Seven case-control studies with a total of 1 233 cases and 936 controls were included. A statistical significant association with high myopia was observed in the recessive model (TT vs CT+CC: OR=1.92; 95%CI=1.14-3.23) and codominant model (TT vs CT: OR=1.81, 95%CI=1.19-2.75).

CONCLUSION

The present meta-analysis suggested that lumican -1554 T/C polymorphism might be moderately associated with high myopia susceptibility. This conclusion warrants confirmation by further studies.

Phylogenetic relationships among Octopodidae species in coastal waters of China inferred from two mitochondrial DNA gene sequences

Octopus in the family Octopodidae (Mollusca: Cephalopoda) has been generally recognized as a "catch-all" genus. The monophyly of octopus species in China's coastal waters has not yet been studied. In this paper, we inferred the phylogeny of 11 octopus species (family Octopodidae) in China's coastal waters using nucleotide sequences of two mitochondrial DNA genes: cytochrome c oxidase subunit I (COI) and 16S rRNA. Sequence analysis of both genes revealed that the 11 species of Octopodidae fell into four distinct groups, which were genetically distant from one another and exhibited identical phylogenetic resolution. The phylogenies indicated strongly that the genus Octopus in China's coastal waters is also not monophyletic, and it is therefore clear that the Octopodidae systematics in this area requires major revision. It is demonstrated that partial sequence information of both the mitochondrial genes 16S rRNA and COI could be used as diagnostic molecular markers in the identification and resolution of the taxonomic ambiguity of Octopodidae species.

The expression of vasoactive intestinal polypeptide in visual cortex-17 in normal visual development and formation of anisometropic amblyopia

AIMS

To document the expression of vasoactive intestinal polypeptide (VIP) in the visual cortex-17 of kittens with anisometropic amblyopia, and to investigate the relationship between VIP and the development of the visual system.

METHODS

Sixteen normal kittens (4-wk of age) were randomly divided into two groups: control and amblyopic. Amblyopia was produced by atropinization of one eye in eight kittens. Four (2 normal and 2 amblyopia) kittens were sacrificed at weeks 3, 6, 9, or 12 post-treatment respectively. Expression of VIP-mRNA in the visual cortex-17 was detected through in-situ hybridization. Neurons in the visual cortex were visualized by transmission electron microscopy (TEM). The number of neurons was analyzed via light microscopy (LM).

RESULTS

VIP-mRNA expression was increased with age in control kittens but remained nearly static in age-matched anisometropic amblyopic kittens (p < 0.05). The number of VIP-positive cells of amblyopic kittens decreased dramatically when compared to normal age-matched kittens (p < 0.05). The total comparison between different positive ranks suggested a significant difference. The degree of expression between these two groups was significantly different. Ultrastructurally, in the control group, the nuclear membrane of most neurons was discernable and chromatin was evenly distributed within the nucleus. Abundant cytoplasm and tubular-shaped mitochondria were observed. These cells were also rich in Golgi bodies, ribosomes, and endoplasmic reticulum. In amblyopic kittens, nuclei of most neurons were aggregated, the number of ribosomes and Golgi bodies was reduced, mitochondria were swollen, and mitochondrial cristae were shortened or even absent. The endoplasmic reticulum was distended and reduced in magnitude.

CONCLUSIONS

VIP appears to play an important role in visual development, and its mRNA expression is affected by visual experiences. Visual dysfunction may down-regulate the expression of VIP-mRNA by impairing the structure and function of the neurons in the visual cortex, finally leading to amblyopia.

Relationship between higher-order aberrations and myopia progression in schoolchildren: a retrospective study

AIM

To investigate the relationship between higher-order aberration (HOA) and myopic progression in school children.

METHODS

Between April 23, 2011 and August 29, 2011 in the children's myopia outpatient clinic of the West China Hospital of Sichuan University, 148 eyes of 74 schoolchildren were reviewed. HOAs for a 6-mm pupil were measured with an aberrometer. Myopic progression rate was defined according to the change in spherical equivalent refraction (SER) divided by the time span (years). Subjects with myopic progression rate of ≥0.50 diopters (D) were classified as the 'fast' group and the subjects with myopic progression rate of <0.50D were classified as the 'slow' group. A retrospective study was conducted to compare HOA between the two groups, using root mean square (RMS) values and Zernike coefficients.

RESULTS

The RMS values of HOA (t=2.316, P=0.02), HOA without Z4 (0) (t=2.224, P=0.03), third-order aberrations (t'=2.62, P=0.01), and coma (t'=2.49, P=0.01) were significantly higher in the fast group than those in the slow group. The individual Zernike coefficients of Z3 (-1) (t=-2.072, P=0.04) and Z5 (1) (Z =-2.627, P=0.01) displayed statistically significant differences between the two groups. Significant correlations were found between the RMS values of HOA (r=0.193, P=0.019), RMS values of HOA without Z4 (0) (r=0.23, P =0.005), RMS values of coma (r=0.235, P=0.004), RMS values of third-order aberrations (r=0.243, P =0.003), and the progression rate.

CONCLUSION

Our results provide evidence of a relationship between HOA and myopic progression. In a future prospective longitudinal study, we aim to verify whether HOA is a risk factor for myopic progression.

[The relationship between refractive error and influencing factors in children]

OBJECTIVE

To investigate the influence of refractive factors, including axial length, cornea power and astigmatism, and total astigmatism to refractive errors.

METHODS

Axial length (AL) and cornea power (K) of 295 children (590 eyes) aged 8. 43 years old (4-14 years old) were obtained through IOL-Master, refractive error was measured by retinoscope after cycloplegia. The eyes were divided into 7 groups according to their spherical equivalence (SE). The 7 groups were high myopia, moderate myopia, low myopia, emmetropia, low hyperopia, moderate hyperopia and high hyperopia. AL and cornea parameters of different groups were compared using ANOVA and Pearson's correlation was used to analyze the relationship between SE, AL and cornea astigmatism and total astigmatism respectively.

RESULTS

(1) Of the 7 groups, AL was longest in the high myopia group and shortest in the high hyperopia group. There was a statistically significant difference (P < 0.05) in AL among the 7 groups. (2) High and moderate myopes had the greatest K values and though there was no difference between the 2 groups, they had greater K values compared to other groups (P < 0.05). Moderate hyperopes had the smallest K values which were smaller than any other group except high hyperopia group. (3) SE was negatively correlated with K (r = -0.242, P < 0.001) and positively correlated with cornea astigmatism (r = 0.131, P = 0.001) but had no correlation with total astigmatism. AL was negatively correlated with cornea astigmatism (r = -0.218, P < 0.001) and had no correlation with K and total astigmatism. (4) Multiple linear regression using AL, K and age as independent variable and SE as dependent variable was applied to analyze the relationship of these variables, and the equation was.

CONCLUSION

The bigger the cornea K value and the longer the AL were, the more myopia the eye was. The study showed that cornea K value of high hyperopes became steeper, indicating that the corneas of high hyperopes tried to compensate for the hyperopic refractive error due to short AL so that the eye can grow toward emmetropization; but the corneas of other groups had the same trend as the AL, which caused myopia or hyperopia together. However, generally speaking, the cornea became steeper as myopia got more severe and flatter as hyperopia more severe.

[Ocular higher-order aberrations in patients with neovascular age-related macular degeneration]

OBJECTIVE

To evaluate changes in higher-order aberrations of eyes in patients with unilateral neovascular age-related macular degeneration (nAMD).

METHODS

Thirty two patients with unilateral nAMD were recruited for this study. Biocular higher-order wavefront aberrations for a 6-mm pupil were measured with Zywave II aberrometer (Bausch & Lomb, Zyoptix, USA). The root mean square (RMS) of Zernike coefficients were compared between the eyes with nAMD and the fellow eyes. Relation ship between RMS values and LogMAR vision of the nAMD were analysed.

RESULTS

The total higher-order aberrations (HOAs), third order aberrations (RMS3), sphere aberration (SA), coma, coma along x axis, and horizontal trefoil in the eyes with nAMD were all significantly greater than those in the fellow eyes (P < 0.05). Increases of vertical trefoil and coma were found to be associated with increased LogMAR values (r(s) = 0.377, P = 0.034; r(s) = 0.416, P = 0.018).

CONCLUSION

Higher-order aberrations in nAMD are greater than normal eyes, which may have effects on distant corrected visual acuity. Examinations of higher-order aberrations should be added into visual function evaluations of nAMD.

[Retinal nerve fiber layer and macular thickness in the fellow eyes of patients with anisometropic amblyopia]

OBJECTIVE

To measure the retinal structure of the fellow eyes of patients with anisometropic amblyopes with retinal nerve fiber layer thickness (RNFLT), macular thickness (MT), and their correlations with axial length (AL) and spherical equivalent (SE).

METHODS

AL was measured by IOLMaster. RNFLT and MT were obtained through optical coherence tomography (OCT). The data of the 56 unilateral amblyopes (56 fellow eyes) were compared with those of 170 normal eyes from 85 age-matched people.

RESULTS

The fellow eyes had thicker RNFLT (RNFLT-fc), temporal RNFLT (RNFLT-t) and inferior (RNFLT-i); and thinner nasal RNFLT (RNFLT-n) than the normal eyes. But no statistically significant differences in superior RNFLT (RNFLT-s) and MT were found between the fellow eyes and normal eyes. After adjustments for age, gender and AL or SE, only the change of RNFLT-t remained significant (P < 0.05 ). Partial correlation analysis between the thickness values and AL/SE adjusted for age and gender showed different trends between the fellow eyes and normal eyes. Multiple linear regression adjusted for age and gender also obtained different coefficients between the fellow eyes and normal eyes. Independent sample t test found no difference in thickness parameters between occlusion and non-occlusion eyes in patients with anisometropic amblyopes.

CONCLUSION

Fellow eyes of patients with anisometropic amblyopes have subnormal retinal structure despite a normal corrected visual acuity. Occlusion does not affect the retinal structure. AL or SE can affect the measurements of RNFLT.

Hydrothermal synthesized bismuth ferrites particles: thermodynamic, structural, and magnetic properties

A family of bismuth ferrites (BFO), including Bi2Fe4O9, BiFeO3, and Bi25FeO39 with different morphologies, has been prepared by the hydrothermal method assisted by different alkaline mineralizers. X-ray diffraction refinement calculations are carried out to study the crystal structures of bismuth ferrites. A thermodynamic calculation based on the dissolution-precipitation model was carried out to analyze the hydrothermal synthesis of BFO powders. Magnetic measurements of the obtained bismuth ferrites show different magnetic properties from 5 K to 350 K.

Spin-transfer torque in nanoscale magnetic devices

We discuss recent highlights from research at Cornell University, Ithaca, New York, regarding the use of spin-transfer torques to control magnetic moments in nanoscale ferromagnetic devices. We highlight progress on reducing the critical currents necessary to produce spin-torque-driven magnetic switching, quantitative measurements of the magnitude and direction of the spin torque in magnetic tunnel junctions, and single-shot measurements of the magnetic dynamics generated during thermally assisted spin-torque switching.

Incidence of diabetic retinopathy in a Hong Kong Chinese population

BACKGROUND

The aim was to examine the progression and regression of diabetic retinopathy within a four-year period in a Chinese population with type 2 diabetes mellitus in a community optometry clinic in Hong Kong.

METHODS

During the period May 2005 to November 2009, 5,160 patients with type 2 diabetes mellitus who had attended at least two diabetic retinopathy screening sessions at a community optometry clinic were included as subjects in this study. All had retinal photographs taken of both eyes, which were of sufficiently good quality for grading. For the purpose of this study, diabetic retinopathy grading was based on the results of the worst eye. The main outcomes were the within four-year incidence of diabetic retinopathy and the incidence of progression and regression of diabetic retinopathy.

RESULTS

Of the 5,160 subjects in this study, 3,647 had no diabetic retinopathy, while 1,513 had diabetic retinopathy at the baseline visit. Of those 3,647 subjects with no diabetic retinopathy, the within four-year cumulative incidence of any diabetic retinopathy, mild or moderate non-proliferative diabetic retinopathy and sight-threatening diabetic retinopathy was 15.16 per cent, 14.45 per cent, 0.69 per cent and 0.03 per cent, respectively. Of those 1,513 subjects with diabetic retinopathy at baseline, the within four-year progression incidence of diabetic retinopathy was 6.61 per cent and the regression incidence of diabetic retinopathy was 45.54 per cent.

CONCLUSION

The high regression incidence of diabetic retinopathy suggests that it might not be necessary for all patients with diabetes to be screened annually. Other methods to determine the screening frequency for an individual patient should be explored.

[Characterize the differences between anisometropic amblyopes and normal people when discriminating different pictures under various degrees of Gauss noises]

OBJECTIVE

To observe the differences between anisometropic amblyopes and normal people when all of them were asked to discriminate those topological and non-topological pictures embedded in Gauss noises.

METHODS

Stimulus pictures (noise variance were 0.04, 0.08, 0.12 respectively) were run using Matlab software, the error ratios of identification of amblyopia groups and control groups were recorded.

RESULTS

The P-values of anisometropic amblyopes were 0.06 (closure pictures) and 0.088 (disclosure pictures) under the different experimental lasting time. No matter whenever the experimental lasting time and whatever the characteristics of the pictures, the error ratios of identification of amblyopia groups were higher than that of control groups, except for closure pictures at 5 s.

CONCLUSION

The capabilities of amblyopes when discriminate the different pictures were lower than that of normal groups. We found that different outcomes of amblyopia groups were caused by their own perception defect.

[MR DTI and DTT study on the development of optic radiation in patients with anisometropia amblyopia]

OBJECTIVE

To evaluate the development of optic radiations (ORs) in patients with anisometropia amblyopia using magnetic resonance diffusion tensor imaging (DTI) and diffusion tensor tractography (DTT), and to explore possible mechanism of pathogenesis of amblyopia.

METHODS

Brain scan was performed with 3.0 Tesla scanner on 8 patients with anisometropia amblyopia and 15 control subjects with normal sights. The fractional anisotropy (FA) values, the apparent diffusion coefficient (ADC) values, the numbers of neural fiber bundle of ORs, and the voxel numbers of ORs were compared between the patients with anisometropia amblyopia and those with normal sights and between the ipsilateral ORs and the contralateral ORs in the patients with amblyopia.

RESULTS

No differences in the FA values, the ADC values, the numbers of neural fiber bundle of ORs and the voxel numbers of ORs were found between the ipsilateral ORs and the contralateral ORs in the patients with amblyopia (P > 0.05). Significant decreases in the FA values and the voxel numbers of ORs were found in the patients with amblyopia compared with the controls (P < 0.05). No differences in the voxel numbers of both ORs in the anterior parts were found between the patients with amblyopia and the controls (P > 0.05). However, the patients with amblyopia had more voxel numbers of ORs in the posterior parts than the controls (P < 0.05). The differences in the ADC values and the numbers of neural fiber bundle of ORs between the patients with amblyopia and the controls were not significant (P > 0.05).

CONCLUSION

The compactability, integrity and directivity of ORs decrease in patients with anisometropia amblyopia. The projection of OR fibers is abnormal. The ORs are underdeveloped, especially in the posterior parts, although no abnormal morphologic changes occur. The DTI and DTT can detect the underdevelopment of optic radiations in patients with anisometropia amblyopia indirectly.

[Contrast sensitivities of the fellow eyes in children with anisometropic and strabismic amblyopia]

OBJECTIVE

To investigate the contrast sensitivities of the fellow eyes in children with anisometropic and strabismic amblyopia.

METHODS

A retrospective study was undertaken. Medical records containing contrast sensitivity data of the fellow eyes in 107 children with anisometropic amblyopia, 110 children with strabismic amblyopia, and 30 normal children were retrieved. The contrast sensitivities of the fellow eyes in those children were compared using independent t-test and one-way analysis of variance (ANOVA) with post hoc (modified LSD) multiple comparison test.

RESULTS

Contrast sensitivity functions of the fellow eyes of children with anisometropic and strabismic amblyopia were weaker than those of the controls. The fellow eyes of children with moderate and severe strabismic amblyopia had better contrast sensitivities than those with anisometropic amblyopes. In strabismic amblyopic children, the contrast sensitivities of the fellow eyes grew with the degree of amblyopia. Occlusion therapy did not change contrast sensitivities of the fellow eyes.

CONCLUSION

The abnormal intraocular interactions between amblyopic and nonamblyopic "normal" eyes decrease the contrast sensitivity functions of the fellow eyes. Compared with anisometropic amblyopic children, the fellow eyes of children with moderate and severe strabismic amblyopia show more superiority in the binocular competition. Occlusion therapy may not depress contrast sensitivities of the fellow eyes in children with amblyopia.

Polymorphism of the pig 17beta-hydroxysteroid dehydrogenase type1 (HSD17B1) gene and its association with reproductive traits

17beta-Hydroxysteroid dehydrogenase type 1 (HSD17B1) is a key enzyme of 17beta-estradiol biosynthesis, which might play an important role in follicular development of the ovary. In this study, we isolated the complete coding sequence of porcine HSD17B1 gene and its unique intron sequences of porcine HSD17B1 gene, identified a single nucleotide polymorphism (SNP: A/C) in intron 4, and developed a PCR-MvaI-RFLP genotyping assay. Association of the SNP and litter size was assessed in two populations (purebred Large White and a experimental synthetic Line (DIV) sows). Statistical analysis demonstrated that, in the first parity, AC animals in experimental synthetic Line (DIV) sows had 0.52 more piglets born compared to the CC animals (P<0.05). In the all parities, pigs with the AA genotype had an additional 1.11 and 0.96 piglets born alive compared to the CC animals (P<0.05) in both experimental synthetic Line (DIV) and purebred Large White, respectively. Experimental synthetic Line (DIV) sows inheriting the AC genotype had additional 0.84 piglets born alive compared to the CC animals (P<0.01) in all parities. In addition, significant additive effect of -0.55+/-0.24 piglets/litter and -0.48+/-0.22 piglets/litter on piglet born alive was detected in both experimental synthetic Line (DIV) sows and purebred Large White lines (P<0.05), respectively. Therefore, HSD17B1 gene was significantly associated with litter size in two populations and could be a useful molecular marker in selection for increasing litter size in pigs.

Study of using microfiltration and reverse osmosis membrane technologies for reclaiming cooling water in the power industry

A study of using dual membrane technologies, microfiltration (MF) and reverse osmosis (RO), for reclaiming blowdown of the cooling tower was conducted at ZJK power plant, Hebei province, China. The study shows that the combined MF-RO system can effectively reduce water consumption in the power industry. The results indicate that MF process is capable of producing a filtrate suitable for RO treatment and achieving a silt density index (SDI) less than 2, turbidity of 0.2 NTU. The water quality of RO effluent is very good with an average conductivity of about 40 micros/cm and rejection of 98%. The product water is suitable for injection into the cooling tower to counteract with cooling water intrusion. After adopting this system, water-saving effectiveness as expressed in terms of cycles of concentration could be increased from 2.5-2.8 times to 5 times.

Cytomegalovirus infection in pregnancy

OBJECTIVES

To investigate the effects of intrauterine human cytomegalovirus (HCMV) infection on pregnancy outcomes and infant development.

METHODS

The study group consisted of the HCMV-IgM-positive offspring of 75 pregnant women, and a control group of the non-infected offspring of 73 pregnant women. Chorionic villi, amnionic fluid, and umbilical blood were obtained to detect HCMV-late mRNA with a reverse transcriptase-polymerase chain reaction (RT-PCR) assay. The pregnancy outcomes were followed up. For all offspring, neurological development was evaluated with neurosonography, audiologic development with the brainstem auditory evoked potential (BAEP), and psychomotor development with the Beyley Scale of Infant Development (BSID).

RESULTS

In the study group the positive rate of late mRNA was 50% in the chorionic villi and 67.65% in the amnionic fluid and the umbilical blood; the incidence of abnormal pregnancy outcomes (abortion, preterm delivery, stillbirth, etc.) was much higher than in the control group (40% vs. 6.57%; chi(2)=24.06; P=0.001); the abnormal rate of neurosonography results at birth and 3 months after birth was higher in the study group than in the control group (P<0.05), as were BAEP values 4 months after birth (chi(2)=8.960; P=0.003). Scores for the Infant Mental Development Index (MDI) were apparently lower than in the control group. When congenitally infected children were tested at the age of 5.5-6.5 years with the Wechsler Preschool and Primary Scale of Intelligence (WPPSI), their rate of mental retardation was still found to be approximately 20%.

CONCLUSIONS

Intrauterine HCMV infection is closely related to abnormal pregnancy outcomes, infant neurological damage, mental retardation, and hearing loss.

Rb-associated protein 46 (RbAp46) suppresses the tumorigenicity of adenovirus-transformed human embryonic kidney 293 cells

The retinoblastoma suppressor (Rb)-associated protein 46 (RbAp46) is a nuclear protein of the WD-repeat protein family and a component of the histone deacetylase complex that physically interacts with Rb. We demonstrated that RbAp46 is a gene up-regulated by the Wilms' tumor suppressor (WT1) and functions as a negative regulator of cell growth. Here we have investigated the ability of RbAp46 to inhibit malignant phenotype of adenovirus-transformed human embryonic kidney (HEK) 293 cells in tumorigenesis assays. We have found that expression of RbAp46 suppressed clonal growth of HEK 293 cells in soft agar and inhibited tumor growth of these cells in nude mice. Furthermore, expression of RbAp46 resulted in an increase of cells in the G2/M fraction of cell cycle and augmented apoptosis in serum-starved cells. The results suggest that high levels of RbAp46 expression inhibit the transformation of tumor cells through interfering with normal cell cycle and/or enhancing apoptotic cell death.

Analysis of the role of AML1-ETO in leukemogenesis, using an inducible transgenic mouse model

As reported previously, AML1-ETO knock-in mice were generated to investigate the role of AML1-ETO in leukemogenesis and to mimic the progression of t(8;21) leukemia. These knock-in mice died in midgestation because of hemorrhaging in the central nervous system and a block of definitive hematopoiesis during embryogenesis. Therefore, they are not a good model system for the development of acute myeloid leukemia. Therefore, mice were generated in which the expression of AML1-ETO is under the control of a tetracycline-inducible system. Multiple lines of transgenic mice have been produced with the AML1-ETO complementary DNA controlled by a tetracycline-responsive element. In the absence of the antibiotic tetracycline, AML1-ETO is strongly expressed in the bone marrow of AML1-ETO and tet-controlled transcriptional activator double-positive transgenic mice. Furthermore, the addition of tetracycline reduces AML1-ETO expression in double-positive mice to nondetectable levels. Throughout the normal murine lifespan of 24 months, mice expressing AML1-ETO have not developed leukemia. In spite of this, abnormal maturation and proliferation of progenitor cells have been observed from these animals. These results demonstrate that AML1-ETO has a very restricted capacity to transform cells. Either the introduction of additional genetic changes or the expression of AML1-ETO at a particular stage of hematopoietic cell differentiation will be necessary to develop a model for studying the pathogenesis of t(8;21).

Cloning and characterization of a novel human ubiquitin-specific protease, a homologue of murine UBP43 (Usp18)

The ubiquitin-specific proteases (UBP) are a family of enzymes that cleave ubiquitin from ubiquitinated protein substrates. We have recently cloned UBP43, a novel member of this family from AML1-ETO knock-in mice. To analyze the role of UBP43 in hematopoiesis and leukemogenesis, we have cloned a full-length human UBP43 cDNA by screening a human monocytic cDNA library as well as by 5'- and 3'-rapid amplification of cDNA ends analyses. This cDNA encodes a polypeptide of 372 amino acids with all of the structural motifs of a deubiquitinating enzyme. The human UBP43 mRNA is strongly expressed in human liver and thymus. Transfection analysis has demonstrated that UBP43 is a nuclear protein. Interestingly, the gene encoding human UBP43 maps to chromosome 22q11.2. This region, known as DiGeorge syndrome critical region, contains a minimal area of 2 Mb and is consistently deleted in DiGeorge syndrome and related disorders. The syndrome is marked by thymic aplasia or hypoplasia, parathyroid hypoplasia, or congenital cardiac abnormalities. Taken together, our results broaden the understanding of a new human ubiquitin-specific protease, UBP43, and suggest that this gene may also be related to DiGeorge syndrome.

A novel ubiquitin-specific protease, UBP43, cloned from leukemia fusion protein AML1-ETO-expressing mice, functions in hematopoietic cell differentiation

Using PCR-coupled subtractive screening-representational difference analysis, we have cloned a novel gene from AML1-ETO knockin mice. This gene is highly expressed in the yolk sac and fetal liver of the knockin mice. Nucleotide sequence analysis indicates that its cDNA contains an 1,107-bp open reading frame encoding a 368-amino-acid polypeptide. Further protein sequence and protein translation analysis shows that it belongs to a family of ubiquitin-specific proteases (UBP), and its molecular mass is 43 kDa. Therefore, we have named this gene UBP43. Like other ubiquitin proteases, the UBP43 protein has deubiquitinating enzyme activity. Protein ubiquitination has been implicated in many important cellular events. In wild-type adult mice, UBP43 is highly expressed in the thymus and in peritoneal macrophages. Among nine different murine hematopoietic cell lines analyzed, UBP43 expression is detectable only in cell lines related to the monocytic lineage. Furthermore, its expression is regulated during cytokine-induced monocytic cell differentiation. We have investigated its function in the hematopoietic myeloid cell line M1. UBP43 was introduced into M1 cells by retroviral gene transfer, and several high-expressing UBP43 clones were obtained for further study. Morphologic and cell surface marker examination of UBP43/M1 cells reveals that overexpression of UBP43 blocks cytokine-induced terminal differentiation of monocytic cells. These data suggest that UBP43 plays an important role in hematopoiesis by modulating either the ubiquitin-dependent proteolytic pathway or the ubiquitination state of another regulatory factor(s) during myeloid cell differentiation.

Induction of NADPH:quinone reductase by dietary phytoestrogens in colonic Colo205 cells

Phytoestrogens are a group of naturally occurring diphenolic compounds present in legumes, whole grains, fruits, and vegetables. High consumption of phytoestrogen-rich foods has been linked to a reduced incidence of cancers at many sites. A potential mechanism of dietary anticarcinogenesis involves the induction of detoxifying phase II enzymes such as NADPH:quinone reductase (QR). This study, therefore, examined the ability of six prominent phytoestrogens to affect cellular expression of QR in colonic cells. Colo205 cells were cocultured with various concentrations (0.001 to 10.0 microM) of each phytoestrogen, and then were assessed for cytosolic QR activity, cell growth, and QR mRNA expression. A maximum of 6- to 8-fold induction of QR activity was observed for both enterolactone and genistein, although at high concentrations they showed an adverse effect upon cell growth. The concentrations required to double the specific activity of QR for enterolactone and genistein were about 0.04 and 0.14 microM, respectively. A 2- to 3-fold increase of QR specific activity was found with either biochanin A (1.1 microM) or coumestrol (12.0 microM) treatments. No significant effects were found for daidzein or formononetin treatments. QR induction was further confirmed by using reverse transcription-polymerase chain reaction (RT-PCR) techniques to measure mRNA expression. A significant correlation between the expression of QR mRNA and the corresponding QR activity was observed (r = 0.76, P < 0.001). The results demonstrated that certain dietary phytoestrogens are capable of QR induction in Colo205 cells by promoting QR mRNA expression, and suggest a novel mechanism by which dietary phytoestrogens may be implicated in colorectal cancer chemoprevention.