Multiple intracardiac thrombi in a patient with dilated cardiomyopathy.
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Cardiomyopathy, Dilated↗
Biomedical subjects
T Luo
Publications and source records attributed to T Luo.
Distinct roles for Distal-less genes Dlx3 and Dlx5 in regulating ectodermal development in Xenopus.
In vertebrates, there are six or more copies of genes related to the Drosophila pattern formation homeodomain gene Distal-less. Among this family, Dlx3 and Dlx5 share extensive sequence homology and have similar, but distinctive, expression patterns, suggesting that these two factors may have substantially redundant developmental functions. Here we show that at the earliest phases of embryogenesis in Xenopus, there are significant differences between Dlx3 and Dlx5 expression and that this correlates with different functions in the restriction of neural crest and neural plate boundaries, respectively.
Animals↗
Genetic and functional diversity of human immunodeficiency virus type 1 subtype B Nef primary isolates.
We have characterized the functional integrity of seven primary Nef isolates: five from a long-term nonprogressing human immunodeficiency virus (HIV)-infected individual and one each from two patients with AIDS. One of the seven Nefs was defective for CD4 downregulation, two others were defective for PAK-2 activation, and one Nef was defective for PAK-2 activation and major histocompatibility complex (MHC) class I downregulation. Five of the Nefs were tested and found to be functional for the enhancement of virus particle infectivity. The structural basis for each of the functional defects has been analyzed by constructing a consensus nef, followed by mutational analysis of the variant amino acid residues. Mutations A29V and F193I were deleterious to CD4 downregulation and PAK-2 activation, respectively, while S189R rendered Nef defective for both MHC class I downregulation and PAK-2 activation. A search of the literature identified HIVs from five patients with Nefs predominantly mutated at F193 and from one patient with Nefs predominantly mutated at A29. A29 is highly conserved in all HIV subtypes except for subtype E. F193 is conserved in subtype B (and possibly in the closely related subtype D), but none of the other HIV group M subtypes. Our results suggest that functional distinctions may exist between HIV subtypes.
Acquired Immunodeficiency Syndrome↗
Exposure to low pH is not required for penetration of mosquito cells by Sindbis virus.
It is widely held that the penetration of cells by alphaviruses is dependent on exposure to the acid environment of an endosome. The alphavirus Sindbis virus replicates in both vertebrate and invertebrate cell cultures. We have found that exposure to an acid environment may not be required for infection of cells of the insect host. In this work, we investigated the effects of two agents (NH(4)Cl and chloroquine), which raise the pH of intracellular compartments (lysosomotropic weak bases) on the infection and replication of Sindbis virus in cells of the insect host Aedes albopictus. The results show that both of these agents increase the pH of endosomes, as indicated by protection against diphtheria toxin intoxication. NH(4)Cl blocked the production of infectious virus and blocked virus RNA synthesis when added prior to infection. Chloroquine, in contrast to its effect on vertebrate cells, had no inhibitory effect on infectious virus production in mosquito cells even when added prior to infection. Treatment with NH(4)Cl did not prevent the penetration of virus RNA into the cell cytoplasm or translation of the RNA to produce a precursor to virus nonstructural proteins. These data suggest that while these two drugs raise the pH of endosomes, they do not block insect cell penetration. These data support previous results published by our laboratory suggesting that exposure to an acid environment within the cell may not be an obligatory step in the process of infection of cells by alphaviruses.
Aedes↗
Human immunodeficiency virus type 1 Nef-induced CD4 cell surface downregulation is inhibited by ikarugamycin.
One well-characterized in vitro function of Nef is its ability to remove CD4, the human immunodeficiency virus (HIV) receptor, from the cell surface. Nef accomplishes this by accelerating the internalization and degradation of CD4. Current models propose that Nef promotes CD4 internalization via an increased association of CD4 with clathrin-coated pits (CCP). Here, we investigated the effect of a naturally occurring antiprotozoan antibiotic, ikarugamycin (IKA), on CD4 cell surface expression in human monocytic cells stably expressing HIV type 1 SF2 Nef. IKA was able to efficiently restore CD4 cell surface expression in Nef-expressing cells without affecting either CD4 synthesis or Nef expression. In addition, we demonstrate that IKA is also capable of efficiently blocking CD4 down-modulation in response to phorbol myristate acetate. Our data suggest that IKA may be an efficient and useful inhibitor of CCP-dependent endocytosis.
Anti-Bacterial Agents↗
Differential regulation of Dlx gene expression by a BMP morphogenetic gradient.
Three members of the vertebrate Distal-less gene family, Dlx3, 5 and 6, are transcribed in early gastrula embryos of Xenopus laevis. This expression is confined to ectoderm and is excluded from the presumptive neural plate region. Expression of all three genes is dependent upon BMP signaling, with significant differences in how the three genes respond to the BMP antagonist chordin. This correlates with the different expression domain boundaries in vivo for Dlx3 compared to Dlx5 and 6, suggesting that BMP signal attenuation could be the primary factor in determining these different patterns in the gastrula ectoderm.
Animals↗
Differentiation of NIH3T3 fibroblasts into adipocytes induced by peroxisome proliferator activated receptor gamma 2 expression.
OBJECTIVE: To express mouse peroxisome proliferator activated receptor gamma 2 (mPPAR gamma 2) in NIH3T3 fibroblasts mediated by the recombinant retrovirus and study its function. METHODS: The mPPAR gamma 2 gene was subcloned into retrovirus vector pGCEN to generate the recombinant pGCEN/mPPAR gamma 2. Then it was packaged into PA317 cells and selected with G418. Viral supernatants were harvested and then used to infect NIH3T3 fibroblasts. PPAR gamma activator 5, 8, 11, 14-eicosatetraynoic acid (ETYA) was used to induce the mPPAR gamma 2-expressing NIH3T3 cells into adipocyte differentiation. RESULTS: The recombinant retrovirus pGCEN/mPPAR gamma 2 was constructed, and the higher titers of the viral supernatants were obtained. mPPAR gamma 2 was expressed in NIH3T3 cells mediated by the recombinant retrovirus. Lipid accumulation obviously existed in these induced adipocytes which morphologically resembled mature adipocytes in vivo and expressed tissue specific adipocyte P2 (AP2) and Leptin genes. CONCLUSIONS: An adipocyte differentiation model in vitro was successfully established. The work is the basis for further research on the molecular mechanism of adipocyte differentiation induced by PPAR gamma 2.
3T3 Cells↗
[Adipocytes differentiation of NIH3T3 cells induced by peroxisome proliferator activation receptor gamma 2 expression].
OBJECTIVE: To express the mouse peroxisome proliferator activated receptor gamma 2(mPPAR gamma 2) in NIH3T3 cells mediated by the recombinant retrovirus and study its function. METHODS: mPPAR gamma 2 gene digested from the recombinant plasmid pcDNA3/mPPAR gamma 2 and confirmed to contain the target gene segment with fluorescence-sequencing was subcloned into retrovirus vector pGCEN to generate the recombinant retrovirus pGCEN/mPPAR gamma 2. The recombinant retrovirus pGCEN/mPPAR gamma 2 and pGCEN were packaged with PA317 cells and anti-G418 clones of PA317 cells were selected. Viral supernatants were collected and used to infect NIH3T3 cells. Peroxisome proliferator activated receptor gamma 2 (PPAR gamma 2)-expressing NIH3T3 cells cultured in the differentiation media containing PPAR gamma activator ETYA were induced into adipocytes. RESULTS: The recombinant retrovirus pGCEN/mPPAR gamma 2 was constructed, 5 x 10(4) CFU/ml of the viral supernatants containing pGCEN/mPPAR gamma 2 and 6 x 10(5) CFU/ml of the viral supernatants containing pGCEN were obtained. mPPAR gamma 2 was expressed in NIH3T3 cells mediated by the recombinant retrovirus. Lipid accumulation obviously existed in PPAR gamma 2-expressing NIH3T3 cells at 10 days postdifferentiation and the lipid-containing cells morphologically resembled the mature adipocytes in vivo. CONCLUSION: An adipocyte differentiation model in vitro was established. The work is the basis for further researches on the molecular mechanism of adipocyte differentiation induced by PPAR gamma 2.
3T3 Cells↗
The electroretinogram in patients with retinal vascular occlusion.
PURPOSE: To measure and analyze the electroretinogram (ERG) in patients with retinal vascular occlusion. METHOD: Fifty-eight cases (59 eyes) of retinal vascular occlusion and the fellow eyes of 47 cases were tested with Ganzfeld ERG. The scotopic and photopic ERG, and oscillatory potentials were tested according to the ERG standard of ISCEV. RESULTS: The abnormal rates of OPs and b wave were higher in retinal vascular occlusion. The abnormal ERG appeared mostly in CRVO among four types of retinal vascular occlusion. The comparisons of some amplitudes and latencies between the fellow eyes and the affected eyes showed statistically significant difference. CONCLUSION: The oscillatory potentials and b waves have important roles in evaluating the retinal function of patients with retinal vascular occlusions. There are some clinical significance for comparing ERG between the affected eye and the fellow eye.
Adolescent↗
Highly enhanced hepatic masses seen on CT during arterial portography: early hepatocellular carcinoma and adenomatous hyperplasia.
BACKGROUND: To describe computed tomographic (CT) features of highly enhanced hepatic masses as seen on CT during arterial portography (CTAP) and to survey the varieties of hepatic lesions associated with such findings. METHODS: CTAP files for 400 patients were reviewed, on the basis of which six patients with highly enhanced hepatic masses were selected. These six patients also subsequently underwent CT during hepatic arteriography (CTHA) on the same day. All the patients had chronic liver damage, which was cirrhotic in five cases. Five had a current diagnosis and one had a history of hepatocellular carcinoma (HCC). RESULTS: Solitary highly enhanced masses were observed on CTAP in three patients, three masses were seen in one patient and multiple (10-12) masses in the other two patients. All the CTAP-enhanced masses except one were round in shape and homogeneous in attenuation. The size of the mass ranged from 6 to 25 mm in diameter. In all except two nodules in one patient, the masses were hypoattenuated on CTHA. On histopathological examination of five nodules in three patients, the nodular lesions were consistent with so-called early HCC (well-differentiated HCC of Edmondson I) in four nodules and adenomatous hyperplasia in the other nodule. CONCLUSIONS: Highly enhanced hepatic masses relative to the surrounding liver parenchyma have been sporadically noted on CTAP, especially in patients with liver cirrhosis. When present, such nodules are typically hypoattenuated on CTHA and histological features are consistent with early HCC and adenomatous hyperplasia.
Adenoma↗
[The clinical application of different brightness and different saturation D-15 tests].
PURPOSE: To compare the clinical application of different brightness and different saturation D-15 tests. METHODS: Eighteen normal subjects (30 eyes), 19 cases (38 eyes) of congenital color vision defects and 36 cases (59 eyes) of eye diseases were tested with Panel D-15 test, Hann's double D-15 test, middle and low saturation CAS-PI (Psychological Institute, Chinese Academy of Sciences) D-15 tests. RESULTS: A few of the normal eyes made minor errors in the low saturation D-15 tests. All of the protanopes and deuteranopes could be detected correctly. Protanomalias and deuteranomalias showed normal arrange or some type of abnormal arranges in all of the 5 sets of D-15 tests. In sick eyes, the abnormal rates were the highest in the low saturation D-15 tests and the lowest in Panel D-15 test. CONCLUSION: The five sets of different brightness and different saturation D-15 tests had similar efficiencies of detecting congenital color vision defects. The abnormal rates of CAS-PI(4/5)D-15 tests and the CAS-PI(2/5)D-15 tests were similar to those of Panel D-15 test and Hann's Double D-15 test. Both tests can be used in the clinical setting.
Adolescent↗
Subtype-dependence of NMDA receptor channel open probability.
NMDA receptor-mediated calcium transients play a critical role in synaptogenesis, synaptic plasticity, and excitotoxicity. NMDA receptors are heteromeric complexes of NR1A combined with NR2A, NR2B, NR2C, and/or NR2D subunits. The NR2 subunits determine a variety of electrophysiological and pharmacological properties of the NMDA receptor complex. In this report, we provide evidence for the first time that there is also a significant difference in peak channel open probability (P(o)) between NMDA receptors composed of NR1A/NR2A and those of NR1A/NR2B subunits. First, whole-cell patch-clamp recordings from human embryonic kidney (HEK) 293 cells expressing NMDA receptors revealed that NR1A/NR2A-mediated peak current densities are approximately four times larger than those of NR1A/NR2B. We show that this fourfold difference is unlikely caused by differences in receptor surface expression, since these levels were similar for the two subtypes by Western blot analysis. To determine whether P(o) contributed to the difference in peak current densities, we used two different open channel antagonists, MK-801 and 9-aminoacridine, in a variety of experimental paradigms. Our results indicate that peak P(o) is significantly higher (twofold to fivefold) for NR1A/NR2A than NR1A/NR2B, with estimated values of approximately 0.35 and 0.07, respectively. These results suggest that a change in the relative expression levels of NR2A and NR2B can regulate peak amplitude of NMDA receptor-mediated excitatory postsynaptic potentials and therefore may play a role in mechanisms underlying synaptic plasticity.
Aminacrine↗
Subtype-specific enhancement of NMDA receptor currents by mutant huntingtin.
Evidence suggests that NMDA receptor-mediated neurotoxicity plays a role in the selective neurodegeneration underlying Huntington's disease (HD). The gene mutation that causes HD encodes an expanded polyglutamine tract of >35 in huntingtin, a protein of unknown function. Both huntingtin and NMDA receptors interact with cytoskeletal proteins, and, for NMDA receptors, such interactions regulate surface expression and channel activity. To determine whether mutant huntingtin alters NMDA receptor expression or function, we coexpressed mutant or normal huntingtin, containing 138 or 15 glutamine repeats, respectively, with NMDA receptors in a cell line and then assessed receptor channel function by patch-clamp recording and surface expression by western blot analysis. It is interesting that receptors composed of NR1 and NR2B subunits exhibited significantly larger currents when coexpressed with mutant compared with normal huntingtin. Moreover, this effect was selective for NR1/NR2B, as NR1/NR2A showed similar currents when coexpressed with mutant versus normal huntingtin. However, ion channel properties and total surface expression of the NR1 subunit were unchanged in cells cotransfected with NR1/NR2B and mutant huntingtin. Our results suggest that mutant huntingtin may increase numbers of functional NR1/NR2B-type receptors at the cell surface. Because NR1/NR2B is the predominant NMDA receptor subtype expressed in medium spiny neostriatal neurons, our findings may help explain the selective vulnerability of these neurons in HD.
Cell Line↗
Infectivity enhancement by HIV-1 Nef is dependent on the pathway of virus entry: implications for HIV-based gene transfer systems.
Retroviruses have been extensively used in the development of gene transfer systems. Recently, there has been a great deal of interest in the use of lentiviruses for gene transfer because they infect nondividing cells. Human immunodeficiency virus (HIV) has been the lentivirus most often used for this purpose, but its genomic complexity and limited tropism present some challenges to the establishment of efficient gene transfer systems. In this paper we present data showing intrinsic differences between the infectivity of wild-type HIV and HIV particles pseudotyped with heterologous envelope glycoproteins. Interestingly, HIV pseudotypes with envelope glycoproteins from the amphotropic murine leukemia virus or the vesicular stomatitis virus (VSV) are 3 and 40 times more infectious than wild-type HIV, respectively. In addition, we show that the reliance on Nef expression for maximal infectivity of HIV particles is dependent on the path of virus entry. The dependence on Nef for higher infectivity is greater for amphotropic pseudotypes and wild-type HIV than for VSV-G pseudotypes. We conclude that VSV-G pseudotypes of HIV vectors are an excellent choice for gene transfer purposes and Nef-mediated viral infectivity enhancement is affected by virus entry pathway.
Anti-Bacterial Agents↗
Forespore expression and processing of the SigE transcription factor in wild-type and mutant Bacillus subtilis.
SigmaE is a mother cell-specific transcription factor of sporulating Bacillus subtilis that is derived from an inactive precursor protein (pro-sigmaE). To examine the process that prevents sigmaE activity from developing in the forespore, we fused the sigmaE structural gene (sigE) to forespore-specific promoters (PdacF and PspoIIIG), placed these fusions at sites on the B. subtilis chromosome which translocate into the forespore either early or late, and used Western blot analysis to monitor SigE accumulation and pro-sigmaE processing. sigE alleles, placed at sites which entered the forespore early, were found to generate more protein product than the same fusion placed at a late entering site. SigE accumulation and processing in the forespore were enhanced by null mutations in spoIIIE, a gene whose product is essential for translocation of the distal portion of the B. subtilis chromosome into the forespore. In other experiments, a chimera of pro-sigmaE and green fluorescence protein, previously shown to be unprocessed if it is synthesized within the forespore, was found to be processed in this compartment if coexpressed with the gene for the pro-sigmaE-processing enzyme, SpoIIGA. The need for spoIIGA coexpression is obviated in the absence of SpoIIIE. We interpret these results as evidence that selective degradation of both SigE and SpoIIGA prevent mature sigmaE from accumulating in the forespore compartment of wild-type B. subtilis. Presumably, a gene(s) located at a site that is distal to the origin of chromosome transfer is responsible for this phenomenon when it is translocated and expressed in the forespore.
Alleles↗
[A community-based survey on hypertension in the medium-aged-elderly in Jiuxianqiao area Beijing].
UNLABELLED: To investigate the epidemiologic features of hypertension and major risk factors in the middle-elderly in Jiuxianqiao area and to develop reasonable preventive strategies, from June to December 1996, nine communities of Jiuxianqiao area were selected for the study. Two thousand and fifty-five middle-elderly (age > or = 50 years old) were investigated including measurement of blood pressure and identifying risk factors of hypertension. Two hundred and thirty-nine hypertensive patients and two hundreds sixty-seven person with normal blood pressure from the study population were examined through oral 75 grams glucose tolerance and electrocardiogram. The prevalence rates of definite and borderline hypertension were 31.6% and 10.9% respectively with a total rate of 42.5%. The prevalence rate of definite hypertension in males was significantly higher than that in females (P < 0.05). The prevalence rate of systolic hypertension was 7.5% but increased paralelly with age (P < 0.05). The prevalence rate of systolic hypertension in females was not significantly higher than that in males. 25.6% of patients with hypertension under investigation denied or were ignorant about having hypertension. The prevalence rates of diabetes, impaired glucose tolerance (IGT) and coronary heart disease in hypertensive group were significantly higher than that in people with normal blood pressure (P < 0.01). CONCLUSION: Hypertension is a disease that seriously endangers the health of the middle-elderly in the community on which calls for more care and education in the community.
Aged↗
[Experimental study on hypoglycemic effect of YTY granules].
OBJECT: To perform experimental pharmacodynamic evaluation of a new TCM antidiabetic drug Yitangyin (YTY). METHODS: Experimkental streptozotocin induced rat diabetes models were subjected YTY treatment and the hypoglycemic effect was evaluated. The proved TCM Yusanxiao (YSX) was used as contrast. RESULTS: The low, middle and high dose YTY groups exhibited significant hypoglycemic effects on the model rats. The efficiency was comparable with YSX. CONCLUSION: The TCM YTY granule is an effective hypoglycmeic agent.
Animals↗
Analysis of oscillatory potentials of flash electroretinogram in frequency domain and time domain in retinal vein occlusion.
PURPOSE: To analyse the parameters of frequency domain and time domain of the OPs in branch retinal vein occlusion (BRVO) and central retinal vein occlusion (CRVO). METHODS: OPs from 9 eyes of BRVO, 9 eyes of CRVO and 40 normal control eyes were tested. The frequency spectra of the OPs were derived through Fast Fourier Transform (FFT). The mean frequency spectra, the total power, the maximum magnitude, the maximum power and the dominant frequency in frequency domain of the OPs from the eyes of BRVO, CRVO and the normal control group were compared with each other. The OPs waveforms were reconstructed with the OPs frequency spectra data by counter-FFT. In time domain, the latencies, the amplitudes and the sum of the amplitudes of the four wavelets of OPs were measured and compared in the above subjects. RESULTS: There were no statistically significant differences in the magnitudes of frequency spectra, the total power, the maximum magnitude and the maximum power in the frequency range from 110 to 250 Hz between BRVO and normal subjects. However, in BRVO, the dominant frequency decreased significantly, the latencies of the first to the third OPs wavelet prolonged significantly, the amplitudes of the first and the second OPs wavelet and the summed amplitude of the four OPs wavelets attenuated significantly. Comparing the results of CRVO with those of normal subjects, there were statistically significant decrease in the magnitudes of frequency spectra from 150 to 180 Hz, there were statistically significant decrease in the total power, the maximum magnitude, the maximum power and the dominant frequency in the frequency range from 110 to 250 Hz, the latencies of the first to the fourth OPs wavelet prolonged significantly, the amplitudes of the first to the third OPs wavelet and the summed amplitude of the four OPs wavelets attenuated significantly. CONCLUSION: Some parameters of OPs in frequency domain and time domain are abnormal in branch retinal vein occlusion and in central retinal vein occlusion, which is more marked in the latter.
Aged↗