[Purine metabolism in Schistosoma japonicum].
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Adenosine Triphosphatases↗
Biomedical subjects
J Guo
Publications and source records attributed to J Guo.
Significance of chromosomal studies in leukemia: karyotype analysis of 28 cases of leukemia and 2 cases of myelofibrosis.
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Adolescent↗
Monovalent cation conductance of the sustained inward current in rabbit sinoatrial node cells.
Under the whole cell clamp, superfusion of the rabbit sinoatrial node cells with a Na+-free solution suppressed the sustained inward current (Ist), and the L-type Ca2+ current (ICa,L) could be recorded on depolarization less negative than -40 mV from the holding potential of -80 mV. On the other hand, replacement of Ca2+ with Mg2+ in the external solution suppressed inward-going ICa,L and isolated Ist. Under this condition, Ist measured as a nicardipine-sensitive current showed an activation threshold between -60 and -70 mV. The conductance sequence of Ist for monovalent ions was determined as Na+ > Li+ >> K+ approximately = Cs+ by replacing the external Na+ with these alkali metal ions. The contribution of Ist to the diastolic depolarization is discussed.
Animals↗
Time of symptom onset of eight common medical emergencies.
Specific time periods of the day may be associated with different frequencies of symptom onset in different diseases. The purpose of the current study was to examine times of symptom onset in eight commonly encountered emergent conditions--cerebral infarction, cerebral hemorrhage, transient ischemic attacks, cardiac dysrhythmias, angina pectoris, acute myocardial infarction, gastrointestinal bleeding, and acute asthma. Data from 4554 cases were retrospectively reviewed. Symptom onset frequency curve diagrams were derived, illustrating peak hours of symptom presentation for each of the eight emergent conditions. Hormonal and metabolic factors that may be related to diurnal variations in symptom onset of the eight diseases are briefly discussed.
Acute Disease↗
Studies on affinity constants of hapten-specific monoclonal antibodies using an antibody-immobilized ELISA.
An enzyme-linked immunosorbent assay to measure affinity constants of hapten-specific monoclonal antibodies has been developed. In this method an antibody-immobilizing format is used. Antibody affinity toward hapten-enzyme tracer is first calculated by using Scatchard's method. Using this affinity, antibody-hapten affinity is then calculated by following the principles of chemical thermodynamics and mass conservation. The affinity from this method agrees with the IC50 values in ELISA. This method is useful in early determination of affinity during monoclonal antibody development. Compared with the antigen-coated format, this method avoids the problem of distinguishing binding of unliganded antibody and singly liganded antibody to antigens on solid phase.
Antibodies, Monoclonal↗
A statistical-based approach to assessing the fidelity of combinatorial libraries encoded with electrophoric molecular tags. Development and application of tag decode-assisted single bead LC/MS analysis.
A statistical sampling protocol is described to assess the fidelity of libraries encoded with molecular tags. The methodology, termed library QA, is based on the combined application of tag decode analysis and single bead LC/MS. The physical existence of library compounds eluted from beads is established by comparing the molecular weight predicted by tag decode with empirical measurement. The goal of sampling is to provide information on overall library fidelity and an indication of the performance of individual library synthons. The minimal sampling size n for library QA is l0 x the largest synthon set. Data are reported as proportion (p) +/- lower and upper boundary (lb-ub) computed at the 95% confidence level (alpha = 0.05). As a practical demonstration, library QA was performed on a 25,200-member library of statine amides (size = 40 x 63 x 10). Sampling was conducted three times at n approximately 630 beads per run for a total of 1902 beads. The overall proportions found for the three runs were consistent with one another: p = 84.4%, lb-ub = 81.5-87.2%; p = 83.1%, lb-ub = 80.2-85.95; and p = 84.5%, lb-ub = 81.8-87.3%, suggesting the true value of p is close to 84% compound confirmation. The performance pi of individual synthons was also computed. Corroboration of QA data with biological screening results obtained from assaying the library against cathepsin D and plasmepsin II is discussed.
Journal Article↗
Distribution of rDNA in the nucleus of Giardia lamblia: detection by Ag-I silver stain.
Previous investigations have proved that diplomonads have primitive cell nuclei and lack a nucleolus. We determined the distribution of ribosomal DNA (rDNA) in diplomonad nuclei that lacked a nucleolus. Giardia lamblia was used as the experimental organism with Euglena gracilis as the control. The distribution of rDNA was demonstrated indirectly by the modified Ag-I silver technique that can indicate specifically the nucleolus organizing region (NOR) by both light and electron microscopy. In ultrathin sections of silver stained Euglena cells, all silver grains were concentrated in the fibrosa of the nucleolus, while no silver grains were found in the cytoplasm, nucleoplasm, condensed chromosomes or pars granulosa of the nucleus. In the silver stained Giardia cells, no nucleolus was found, but a few silver grains were scattered in the nucleus. This suggests that the rDNA of Giardia does not form an NOR-like structure and that its nucleus is in a primitive state.
Animals↗
Transdermal delivery of insulin in mice by using lecithin vesicles as a carrier.
The present study was undertaken to characterize the preparation of flexible lecithin vesicles containing insulin and to assess the enhancing effect of these flexible vesicles on the transdermal delivery of a hydrophilic protein. Both conventional and flexible vesicles were prepared by reverse-phase evaporation and treated further by sonication. The free drug was separated from vesicles by column chromatography and analyzed by HPLC. Both conventional and flexible vesicles were transparent colloidal dispersions. The particle size of the conventional and flexible vesicles was 73.5 nm and 87.1 nm with a polydispersity index of 44.5% and 15.6%, respectively. The entrapment efficiencies of conventional and flexible vesicles were 35% and 81%, respectively. When vesicles were nonocclusively applied onto the abdominal mice skin at a dose of 0.90 IU/cm2, in vivo hypoglycemic study showed the drop percentage of blood glucose by flexible vesicles was 21.42 +/- 10.19% at 1 hr, reached 61.48 +/- 8.97% at 5 hr, and was larger than 50% within 18 hr. Conventional vesicles, insulin solution, and saline had no hypoglycemic effect. Probably due to the incorporation or adsorption of a certain amount of insulin into the flexible vesicles during the mixing process, blank flexible vesicles mixed with insulin solution had a certain degree of hypoglycemic effect, though much less than the effect of flexible vesicles containing insulin (p < 0.05). Flexible vesicle may become a promising carrier for the transdermal delivery of hydrophilic polypeptides.
Administration, Cutaneous↗
Solubilization and pharmacokinetic behaviors of sodium cholate/lecithin-mixed micelles containing cyclosporine A.
The purpose of this study was to investigate the solubilization capacity of sodium cholate/lecithin-mixed micelles and to evaluate the potential of mixed micelles as a carrier of cyclosporine A for intravenous infusion. The mixed micelles were prepared by coprecipitation technique. The formulation components and preparation procedures, which may affect the solubilization of cyclosporine A, were studied. The dilution stability of cyclosporine A-containing mixed micelles was investigated. Pharmacokinetic behaviors of mixed micelles in rabbits after intravenous infusion were compared with Sandimmun. Results showed the strategies to increase the solubility of cyclosporine A include lowering the molar ratio of sodium cholate to lecithin, increasing the concentration of lecithin, and reducing the ionic strength of the dispersion medium and temperature. The largest solubility was found to be 5.42 +/- 0.16 mg/ml. The leakage of mixed micelles in 5% glucose (5.84%) was much less than that in saline solution (36.7%). The relative bioavailability of mixed micelles versus Sandimmun was 112 +/- 20%, and statistical analysis demonstrated both preparations were bioequivalent. Sodium cholate/lecithin-mixed micelles are promising carriers in the intravenous delivery of cyclosporine A, considering their capability of large-scale production and low-toxic property.
Animals↗
The renal TGF-beta system in the db/db mouse model of diabetic nephropathy.
The prosclerotic cytokine transforming growth factor beta 1 (TGF-beta1) has been causally implicated in renal pathobiology in diabetes. We sought evidence that the TGF-beta system participates in the nephropathic process in the db/db mouse, a hyperinsulinemic model of genetic diabetes that develops abnormalities in renal morphology and function that parallel those in human diabetic nephropathy. In support of this hypothesis, we found that steady state levels of mRNA encoding the TGF-beta type II receptor were significantly increased in renal cortex from db/db diabetic mice. Additionally, the translated TGF-beta type II receptor protein, assessed by immunoblot, also was increased in diabetic kidneys. However, in contrast to rodents with insulin-deficient diabetes, steady state levels of mRNA encoding TGF-beta1 in the renal cortex of diabetic db/db mice did not differ from those in cortex from nondiabetic (db/m) littermate controls. Further, concentrations of TGF-beta protein, measured by immunoassay and bioassay, were significantly lower in extracts prepared from renal cortex of diabetic animals compared with those from nondiabetic controls. Urine and serum concentrations of immunoreactive TGF-beta1 also were reduced in diabetic mice. The findings are consistent with upregulation of TGF-beta type II receptor activity as a consequence of hyperglycemia in the hyperinsulinemic db/db mouse and suggest that hyperinsulinemia inhibits TGF-beta1 production. The results further suggest that type II receptor upregulation is a contributing factor to the increased gene expression of renal cortical mRNAs encoding the extracellular matrix proteins fibronectin and alpha 1 (IV) collagen and to the renal abnormalities observed in this animal model.
Animals↗
Prenatal determination of a variable number of tandem repeats in intron 40 of the von Willebrand factor gene from maternal peripheral blood using the polymerase chain reaction.
To determine a fetal variable number of tandem repeats (VNTR) without using fetal tissues, we amplified the whole VNTR region in intron 40 of the von Willebrand factor gene from maternal peripheral blood by the polymerase chain reaction and then separated the amplified fragments by a nonhydratable polyacrylamide gel with an electrolyte gradient. After water elution from the gel, each preliminary product was amplified for the second time and then digested by Alu I restriction endonuclease. Then the VNTR was examined using a hydratable polyacrylamide gel with an electrolyte gradient. We successfully identified the fetal VNTR from 6 cases of 10 maternal peripheral blood samples and 2 cases of 6 maternal blood samples after parturition. This study might offer a theoretical basis for the noninvasive diagnosis of genetic disorders and identification of disputed paternity with common primers.
Alleles↗
NLPR, an agonist of AVP4-8, increases NGF gene expression in memory-impaired rat brain.
Oral administration of the tetrapeptide Asn-Leu-Pro-Arg (NLPR) to memory-impaired rats results in improved acquisition and maintenance of behavioural response and also facilitates nerve growth factor (NGF) expression in the brain. It is suggested that NLPR can ameliorate memory disability by promoting NGF gene expression, so implying that NLPR is a potential drug candidate for curing memory impairment.
Animals↗
Morphological evidence for the location of calcitonin gene-related peptide (CGRP) immunoreactivity in rat lymphocytes.
Calcitonin gene-related peptide (CGRP) is widely distributed in sensory neurons and nerve fibers. It was shown recently in our laboratory that there was CGRP-immunoreactivity (CGRP-ir) in extract of rat lymphocyte of thymus and mesenteric lymph node by radioimmunoassay and reversed-phase HPLC. The aim of this study was to detect the CGRP-ir location in the rat lymphocyte by immunocytochemical method. Single cells isolated from thymus and mesenteric lymph node of male Wistar rat (200-250 g) were suspended in RPMI-1640 medium. After adhesion to plate wall and through nylon wool fiber columns, T cell-riched suspension was obtained. Immunocytochemical ABC method was performed in cell suspension, the specific antiserum (1:200 diluted) was rabbit anti-human CGRP. The cells were examined under light microscope after smeared on glass slide by Shandon Cytospin. The results showed that some lymphocytes were CGRP-ir positive. The positive granules were seen as ring, plaque, cap or spot distributing on the surface or inside the cell. The results indicate that CGRP-ir may be located in some rat T lymphocytes. This work provides new information about the interaction between the nervous and the immune systems. The functional significance of CGRP located in lymphocytes needs to be further studied.
Animals↗