Conformational studies of poly((S)-beta-aminobutyric acid).
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Alcohols↗
Biomedical subjects
F Chen
Publications and source records attributed to F Chen.
Phenylbutyrate attenuates the expression of Bcl-X(L), DNA-PK, caveolin-1, and VEGF in prostate cancer cells.
Phenylbutyrate (PB) is a histone deacetylase inhibitor that has been shown to induce differentiation and apoptosis in various cancer cell lines. Although these effects are most likely due to modulation of gene expression, the specific genes and gene products responsible for the effects of PB are not well characterized. In this study, we used cDNA expression arrays and Western blot to assess the effect that PB has on the expression of various cancer and apoptosis-regulatory gene products. We show that PB attenuates the expression of the apoptosis antagonist Bcl-X(L), the double-strand break repair protein DNA-dependent protein kinase, the prostate progression marker caveolin-1, and the pro-angiogenic vascular endothelial growth factor. Furthermore, PB was found to act in synergy with ionizing radiation to induce apoptosis in prostate cancer cells. Taken together, our results point to the possibility that PB may be an effective anti-prostate cancer agent when used in combination with radiation or chemotherapy and for the inhibition of cancer progression.
Apoptosis↗
The effect of chymotrypsin on the determination of total alpha-glucosidase activity in seminal plasma and the correlation between alpha-glucosidase level and semen parameters.
To evaluate the effect of chymotrypsin on the examination of alpha-glucosidase activity in seminal plasma, thirty-nine samples of fresh liquefied semen with or without chymotrypsin and forty-eight samples of fresh un-liquefied semen with chymotrypsin were determined for the total alpha-glucosidase activity in seminal plasma. The total alpha-glucosidase level of each sample was assayed by the method of glucose oxidase. The correlations between alpha-glucosidase level and semen parameters, including semen volume, pH, sperm concentration, grade a and b motility and total motility, were analyzed with SPSS 11.0 software. The results showed that chymotrypsin had no effect on seminal alpha-glucosidase activity determination. Chymotrypsin could improve the liquefaction for un-liquefied semen, and there was no significant difference of alpha-glucosidase activity between liquefied and un-liquefied semen samples. There were significantly positive correlations between seminal alpha-glucosidase activity (U/ml) and sperm concentration (r = 0.338, p = 0.015) and between total alpha-glucosidase activity (U/ejaculate) and semen volume (r = 0.677, p = 0.000). However, there was no significant correlation between alpha-glucosidase level (U/ml) and semen volume, pH, sperm motility or grade a and b motility (r = -0.234 approximately 0.077, p = 0.099 approximately 0.993). The data indicated that chymotrypsin could be added into the un-liquefied semen samples for alpha-glucosidase activity determination, and there were different correlations between seminal alpha-glucosidase level and various semen parameters.
Chymotrypsin↗
Standardization and quality control for the determination of alpha-glucosidase in seminal plasma.
We attempted to provide an instruction for the standardization of alpha-glucosidase level determination and quality controls within the same laboratory and among different laboratories. Each of 51 semen samples was divided into two aliquots, centrifuging at 1000 g for 10 min or 3000 g for 15 min. The alpha-glucosidase level and sperm concentration of each sample were assayed. The alpha-glucosidase level in seminal plasma obtained at 3000 g for 15 min centrifugation was significantly lower than that at 1000 g for 10 min (p = 0.001). An additional 6 samples of seminal plasma with or without phenylmethylsulfonyl fluoride (PMSF), obtained at 3000 g for 15 min centrifugation, were frozen for 20 days, and each of 6 samples was determined for their alpha-glucosidase levels after thawing every other day. There was no significant difference between alpha-glucosidase levels in seminal plasma regardless of the presence of PMSF. The alpha-glucosidase level increased with the length of abstinence period. In conclusion, centrifugal velocity and abstinence time should be standardized in the alpha-glucosidase determination. Frozen seminal plasma may serve as the sample for quality control among clinical laboratories.
Centrifugation↗
The next generation of liposome delivery systems: recent experience with tumor-targeted, sterically-stabilized immunoliposomes and active-loading gradients.
Three topics are discussed. Enhanced anti-tumor efficacy of targeted doxorubicin-containing sterically-stabilized liposomes using an anti-beta1 integrin Fab' ligand. Use of tumor targeting with an internalizing ligand to improve the efficacy of a non-leaky cisplatin-containing sterically-stabilized liposome formulation. Formulation variables (remote-loading with dextran ammonium sulfate, rigid lipid bilayer) used to optimize in vivo performance of a liposomal camptothecin analog.
Ammonium Sulfate↗
Determination of procaine in equine plasma and urine by high-performance liquid chromatography.
The variability in plasma and urine equine procaine measurement between three independent laboratories using current methods led to the development of a sensitive, reliable, and reproducible high-performance liquid chromatographic method. Standardbred mares were administered either a penicillin G procaine preparation intramuscularly or procaine hydrochloride subcutaneously, and blood and urine were collected at defined time intervals. By HPLC the detection limits for procaine in plasma and urine were 1 and 10 ng/mL, respectively. In contrast procaine in plasma could not be detected by GC-NPD, while the urinary detection limit was 50 ng/mL. The concentration of fluoride in the collection tubes and repetitive freeze-thawing modified plasma procaine measurement. Urinary pH was a factor in estimation of urine procaine levels with greater recovery and reproducibility of results at pH 5 as compared to pH 7. This HPLC method provides a simple, sensitive, and reliable quantitation of procaine in equine plasma and urine.
Animals↗
A highly sensitive spectrophotometric method with solid-phase extraction for the determination of methylmercury in human hair.
Methylmercury is the most toxic among the mercury species. In order to provide a quick method to screen samples for methylmercury, a highly sensitive spectrophotometric method was established. The method was based on formation of the red complex of methylmercury with thio-Michler's ketone, which can be extracted with n-butanol. The organic layer was determined at a maximum absorption wavelength of 564 nm. The Lambert-Beer law was obeyed for methylmercury from 1.00 x 10(-7) mol/L to 2.00 x 10(-5) mol/L with a correlation coefficient of 0.9992. The detection limit was 3 x 10(-8) mol/L. The method was used to determine methylmercury in human hair. The recovery was from 94% to 102%, and the relative standard deviation was 2.5%. The results agreed with those obtained by gas chromatography with electron capture detection.
Benzophenones↗
Previous strabismus surgery and eye position under anesthesia.
We studied eye position under general anesthesia in 51 patients with concomitant esotropia or exotropia, divided into two groups. One group consisted of strabismus patients who had had no previous surgery. The second group consisted of strabismus patients who had undergone previous surgery on one (asymmetric) or both (symmetric) eyes. We found that both groups showed either no change or more divergence under general anesthesia in comparison to their preoperative state. Those patients who had had no previous surgery revealed an equal divergence in both eyes. This relationship also held true for those patients who had undergone symmetrical surgery in both eyes. However, those patients who had had surgery in one eye only showed more divergence in the operated eye than in the unoperated one. These findings reflect the mechanical--anatomical factors created by the surgery itself.
Adolescent↗
Möbius and Möbius-like syndromes (TTV-OFM, OMLH).
There exists a spectrum of syndromes characterized by cranial nerve palsies, limb anomalies, and craniofacial malformations. Criteria based on type and severity of limb anomaly or presence or absence of cranial nerve palsy may alter the syndrome nomenclature due to a selection bias but do not appear to benefit syndrome delineation to any extent. Patients with seventh nerve palsy and abduction weakness are usually diagnosed as having Möbius syndrome by ophthalmologists. The observed ocular motility findings range from primarily abduction deficiencies to patients who have a Duane or gaze palsy pattern of horizontal movements. Some cases previously described as "sixth nerve and partial third" may better fall into one of the latter groups, since an isolated adduction deficit as a manifestation of third nerve involvement is rare. The presence of clinical appearance of Duane syndrome in these Möbius-type patients raises the possibility of abnormal innervation of the lateral rectus as an explanation of some patterns of motility observed.
Abducens Nerve↗
Ectopic expression of truncated Sp1 transcription factor prolongs the S phase and reduces the growth rate.
The role of the transcription factor Sp1 in cell growth and survival was investigated by induced expression of its DNA-binding C-terminal fragment. Transfection of a constitutively expressed Sp1-170C plasmid construct into HeLa cells failed to produce viable clones, suggesting that this peptide interferes with cell growth. However, transfection with the muristerone A-inducible vector system produced four clones with low levels of expression of Sp1-170C. Muristerone A transiently induced higher levels of Sp1-170C, and this was accompanied by a reduced growth rate and prolongation of the S phase of the cell cycle. This is the first report that a dominant negative Sp1 can affect the cell cycle.
Base Sequence↗
The swelling behavior and wet morphology of water-absorbable polymer materials.
In this research work, a low-temperature examination method for scanning electron microscopy (SEM) is introduced. A water-absorbable polymer material, the sulfonated polyethylene (SPE) ion-exchange hollow fiber membrane, was used for the experiments. With this low-temperature technique, the wet morphology of the water-absorbable sulfonated polyethylene hollow fiber membrane was revealed. The results obtained from this investigation offer some important information to explain the behavior of the SPE hollow fiber membranes when they are applied in pervaporation separation of water/organic solvent mixtures, such as water/ethylene glycol, water/ethanol, and so forth.
Journal Article↗
Application of monoclonal antibodies in cardiovascular diseases: atherosclerosis and pulmonary emboli imaging.
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Animals↗
Use of fluorescent probes to investigate the metabolic state of Pneumocystis carinii mitochondria.
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Animals↗
Mechanism of tumorigenesis of renal carcinomas associated with the constitutional chromosome 3;8 translocation.
PURPOSE: Members of a family carrying a constitutional balanced translocation [t(3;8) (p14;q24)] have a high risk of developing multiple, bilateral clear-cell renal carcinomas. Two genetic mechanisms of carcinogenesis for this malignancy have been proposed: (1) disruption of a gene at the translocation breakpoint and (2) mutation of the von Hippel-Lindau tumor-suppressor gene at 3p25. This study further evaluates the role of the von Hippel-Lindau gene in the etiology and pathogenesis of t(3;8)-associated renal carcinomas. METHODS: Two new t(3;8)-associated renal carcinomas were tested for mutations in the von Hippel-Lindau gene by single-stranded conformational polymorphism analysis followed by direct DNA sequencing, for loss of alleles on chromosomes 3p and 8, and for methylation abnormalities in the first cloned exon of the von Hippel-Lindau gene. RESULTS: A missense mutation in the von Hippel-Lindau gene was found in one of the two t(3;8)-associated renal carcinomas. This mutation would produce a stop codon and a truncated protein. Both tumors showed a loss of alleles on the derivative 8 chromosome. When these results were combined with the results of our previous studies, two of the four t(3;8)-associated renal carcinomas, which were examined for molecular genetic changes, showed different von Hippel-Lindau somatic mutations. All renal tumors from the 3;8 translocation family showed loss of the translocated portion of chromosome 3. CONCLUSIONS: These results support a mechanism of tumorigenesis in the chromosome (3;8) translocation family that involves the loss of both copies of the von Hippel-Lindau gene.
Carcinoma, Renal Cell↗
Role of hydroxyl radical in silica-induced NF-kappa B activation in macrophages.
Nuclear transcription factor kappa B (NF-kappa B) is a multiprotein complex that regulates a variety of genes important for immunity and inflammation. The present study investigates the silica-induced activation of this transcription factor in mouse macrophage cell line RAW 264.7 cells, the role of free radical reactions in the mechanism of the activation, and its possible inhibition. Tetrandrine, a benzylisoquinoline alkaloid, which has been used as an antifibrotic drug to treat the lesions of silicosis and has been characterized as a hydroxyl radical (.OH) scavenger, inhibited the NF-kappa B activation induced by silica, lipopolysaccharide (LPS), and phorbol 12-myristate 13-acetate (PMA). Catalase, metal chelator, deferoxamine, and the silanol group (SiOH) blocker, poly(2-vinylpyridine-N-oxide) (PVPNO), also inhibited silica-induced NF-kappa B activation. Electron spin resonance (ESR) spin trapping measurements show that both deferoxamine and PVPNO decreased silica-mediated .OH radical generation from H2O2. It is shown that Fe(II) and not Fe(III) is able to cause NF-kappa B activation. The antioxidant, ascorbate, attenuated the NF-kappa B activation induced by silica but not by LPS. The .OH radical scavenger, sodium formate, inhibited NF-kappa B activation induced by silica but had only a minor effect on NF-kappa B activation induced by LPS. The results indicate that silica-mediated free radical generation via the Fenton or Fenton-like reaction (M(n)+ + H2O2-->M(n + 1)+ + OH- + .OH) and silanol groups on the silica surface play an important role in silica-induced NF-kappa B activation.
Alkaloids↗
Treatment of growth arrest by transfer of cultured chondrocytes into physeal defects.
Chondrocytes were cultured from cartilage harvested from the iliac apophysis and knee joints of New Zealand White (NZW) rabbits. An experimental model for growth arrest was created by excising the medial half of the proximal growth plate of the tibia of 6-week-old NZW rabbits. The cultured chondrocytes were embedded in agarose and transferred into the growth-plate defect after excision of the physis. Transfer also was performed after excision of the bony bridge in established growth arrest. In both cases, growth arrest with angular deformation of the tibia was prevented. Histologic studies confirmed the viability of the chondrocytes in the new host physis.
Animals↗
The effect of surgery on the iliac apophysis: an experimental study.
The effect of surgery on the subsequent growth of the iliac apophysis was studied in 30 immature New Zealand White rabbits. Groups of animals were subjected to splitting of the iliac apophysis or excision of part of or the whole apophysis. These animals were compared to a group with a sham operation. Results showed that splitting with subsequent resuturing of the iliac apophysis resulted in normal growth in height but increased growth in width and thickness of the iliac bone. Excision of one third of the iliac apophysis did not interfere with subsequent growth, but excision of two thirds or more of the iliac apophysis resulted in retarded growth of the iliac bone. These experimental studies suggest that the iliac apophysis can be safely split in the surgical approach to a child's hip. Also one third of the iliac apophysis can be safely sacrificed for use as a physeal graft or for chondrocyte cultures.
Animals↗