Organ and functional preservation in the management of genitourinary cancer: bladder, prostate, and penis.
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Humans↗
Biomedical subjects
L Liu
Publications and source records attributed to L Liu.
Peptide transporter function and prolidase activities in Caco-2 cells: a lack of coordinated expression.
Peptide transport and prolidase activities were measured to determine whether the expression of these two components of protein nutrition are coordinately regulated; i.e., whether an increase in the peptide transporter function will necessarily lead to a higher prolidase activity, or vice versa. The results indicated that peptide transporter function and prolidase activity respond differently to cell differentiation and feeding schedules. The results also indicated that peptide transport and prolidase activities were different in two Caco-2 cell "clones", with S-K cells transported peptides at higher rates but had lower total prolidase activities, when compared to ATCC cells. These results suggest that the expression of the peptide transporter function and prolidase activity is not coordinated. In addition, both the transporter and the prolidase activities affected the overall transport of Phe when given as the dipeptide Phe-Pro, supporting the notion that intestinal absorption of peptides is an essential component of amino acid absorption. In conclusion, the evidence suggests that the peptide transporter function and prolidase activity are not coordinately expressed by the human intestinal Caco-2 cells.
Basement Membrane↗
Biochemical and molecular aspects of mammalian susceptibility to aflatoxin B1 carcinogenicity.
Aflatoxin B1 (AFB1) is a fungal toxin that has been implicated as a causative agent in human hepatic and extrahepatic carcinogenesis. In this review, the mechanisms involved in AFB1 toxicity are delineated, in order to describe the features that make a specific cell, tissue, or species susceptible to the mycotoxin. Important considerations include: (i) different mechanisms for bioactivation of AFB1 to its ultimate carcinogenic epoxide metabolite; (ii) the balance between bioactivation to and detoxification of the epoxide; (iii) the interaction of AFB1 epoxide with DNA and the mutational events leading to neoplastic transformation; (iv) the role of cytotoxicity in AFB1 carcinogenesis; (v) the significance of nonepoxide metabolites in toxicity; and (vi) the contribution of mycotoxin-unrelated disease processes. Although considerable controversy remains about the importance of specific events, a great deal has been learned about biochemical and molecular actions of AFB1.
Aflatoxin B1↗
[The relationship between P-selectin on platelet membrane and platelet function in chronic cor pulmonale].
Platelet plays an important role in thromboembolic diseases. It is demonstrated that recurrent pulmonary embolism may cause pulmonary hypertention. In recent years, P-selectin (granule membrane protein, GMP140) was found to be a surface marker for platelet activation. In order to investigate the role of platelet in chronic cor pulmonale, the changes of P-selectin on platelet membrane and its effect on platelet adhesiveness (PAdT) and platelet aggregation (PAgT) were studied. The results showed that the changes of P-selectin PAdT and PAgT in chronic cor pulmonale were significant than those in chronic pulmonary diseases and controls (P < 0.01). There was positive correlation between P-selectin and PAdT (r = 0.6831, P < 0.01) as well as PAgT (r = 0.7142, P < 0.01). The levels of von Willebrand factor (vWF) and fibrinogen (Fg) were markedly increased in chronic cor pulmonale as compared with chronic pulmonary disease and control group (P < 0.01). There was also positive correlation between vWF and PAgT (r = 0.4143, P < 0.05) as well as between Fg and PAgT (r = 0.4392, P < 0.05). It is concluded that platelet plays an important role in the pathogenesis of chronic cor pulmonale.
Aged↗
Inhibition of thrombin by antithrombin III and heparin cofactor II in vivo.
The critical role of thrombin in the pathogenesis of venous and arterial thrombosis, and the effectiveness of glycosaminoglycans as antithrombotic drugs are well known. Antithrombin III is a major inhibitor of thrombin and augmentation of its inhibitory actions by heparin is the basis for the clinical uses of heparin. Recent clinical and experimental studies have demonstrated that another glycosaminoglycan, dermatan sulfate, is an effective antithrombotic drug. Dermatan sulfate catalyses the inhibition of thrombin by heparin cofactor II. The concentrations of heparin cofactor II are higher in the plasmas of individuals with congenital antithrombin III deficiency and pregnant women than controls. The role of heparin cofactor II as a physiologic thrombin inhibitor is unknown. Enzyme-linked immunosorbent assays were used to quantify thrombin-heparin cofactor II and thrombin-antithrombin III endogenous to the plasmas of adult antithrombin III-Hamilton deficient subjects, their siblings with normal antithrombin III levels, pregnant women at term and 3 to 5 days after delivery. Both thrombin-antithrombin III and thrombin-heparin cofactor II complexed with vitronectin were detected in all the plasmas. Significantly, the concentrations of thrombin-heparin cofactor II-vitronectin were higher in the plasmas of congenital antithrombin III deficient subjects and in pre- and post-delivery plasmas than those of normal subjects. In addition, the concentrations of thrombin-heparin cofactor II decreased 3 to 5 days after delivery, reflecting the disappearance of the catalytically active dermatan sulfate elaborated by the placenta. Thus, heparin cofactor II normally inactivates thrombin in vivo, with its role increasing in conditions associated with high levels of heparin cofactor II and/or dermatan sulfate.
Adult↗
[Morphine blocked the exitatory amino acid mediated membrane current in ambigual motoneurons of the rat].
Excitatory postsynaptic potentials (EPSPs) and responses of neurons in the compact formation of the neucleus ambiguus (AMBc) to pressure-ejected or bath-applied test substances were recorded intracellularly from sagittal slices of Sprague-Dawley rat medulla containing subnucleus centralis of solitary complex (NTSc), AMBc and solitarioambigual pathway. In 5 cells, recorded spontaneous EPSPs could be blocked by morphine (3-5 pmol) to AMBc. Electrical stimulation of NTSc evoked EPSPs in AMBc neurons, the amplitude of which were decreased to 71.1 +/- 6.2% (P < 0.001) with the addition to morphine. The morphine effect could be abolished by bath-applied naloxone (50 nmol/L). The amplitude of membrane depolarization induced by pressure-ejected N-methyl-D-aspartate (NMDA, 0.5-1.0 pmol), acetylcholine (3 pmol) and quisqualate (0.1-0.5 pmol) to NTSc could also be decreased by bath-applied morphine (10 mumol/L) respectively to 38.1 +/- 5.7% (P < 0.001), 32.8 +/- 5.5% (P < 0.01) and 29.6 +/- 7.1% (P < 0.05). The above results suggest that morphine is capable of block by NMDA, ACh and non-NMDA receptors, increaseing the M-current and decreasing the permeability of Na+ and Ca2+.
Animals↗
[Langerhans cells and human aural cholesteatoma].
Enzyme histochemical, immunohistochemical and ultramicroscopic analysis of 20 human aural cholesteatoma matrices revealed the presence of Langerhans cells, T lymphocytes, B lymphocytes and HLA-DR positive cells. There was no significant difference of the numerical density on the area of Langerhans cells between the cholesteatoma matrices and the normal ear canal skin. The numerical density on the area of T4 and the ratio of T4/T8 of cholesteatoma were higher than those of the normal ear canal skin. Through cell-to-cell interaction, Langerhans cells probably play a key role in skin-related disorders, including cholesteatoma.
Adolescent↗
An association study between essential hypertension and HLA-DRB1 alleles.
It is well established that genetic and environmental factors are involved in the etiology of essential hypertension (EH). Previous studies have suggested that at least one of the HLA genes is responsible for the genetic susceptibility to EH. Our aim in the present study was to investigate this issue in China by the PCR-SSP HLA-DRB1 typing method. The results showed an increased frequency of HLA-DR2 and a decreased frequency of HLA-DR7 with EH patients compared with controls. We consider that HLA-DR2 may represent a marker for susceptibility to EH in the North Chinese population.
Alleles↗
[The injury of heart of rats sustaining delayed fluid resuscitation after burn shock].
Delayed fluid resuscitation of burn shock may lead to many harmful effects. We investigated the injury of heart of burned rats having no fluid resuscitation, immediate and delayed fluid replacement. We used electron spin resonance (ESR) to determine the presence of oxygen free radicals (OFR). We also found significant increase in malondialdehyde (MDA) in delayed resuscitation group. The activity of lactate dehydrogenase isoenzyme (LDH) and creatine phosphokinase isoenzyme (CPK-MB) were increased in the latter group. Immediate fluid replacement can not protect the heart perfectly. Some new measure should be added to the fluid replacement in burn shock.
Animals↗
[The three dimensional finite element analysis of fracture in mandibular body treated by rigid internal fixations].
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Biomechanical Phenomena↗
[Detection of mutation in insulin receptor gene in patients with essential hypertension].
We have analyzed single-stranded conformational polymorphism (SSCP) to screen for mutation in exon 17 of insulin receptor gene in 46 patients with hypertension and 49 normotensive controls. Three different SSCP patterns were detected in both patients and controls and the frequency of pattern I was 54.3% and 32.7% (chi 2 = 3.71, P = 0.05) in patients and controls respectively; The frequency of pattern II was 61.3% and 26.1% (chi 2 = 10.49, P = 0.001) in controls and patients respectively; the frequency of pattern III did not differ between controls and patients. Based on direct sequencing, the differences between pattern II and pattern I were explained by a mutation substituting at position 1040, GAG1040-->GAA1040, which suggests that codon GAA1040 may be a genetic marker for susceptibility to essential hypertension in Chinese.
Adult↗
[Rapid identification and quantitation of barbiturates in plasma using solid-phase extraction combined with GC-FID and GC-MS method].
A rapid screening method for the quantitation and identification of 7 barbiturates in plasma is presented. The method employs solid-phase extraction at pH 3 using X-5 resin as absorbent. Identification of each barbiturate is achieved by retention time and GC-MS. Detection threshold (0.3-0.5 micrograms.ml-1 in a 0.5 ml plasma sample and 1 microliter injection volume), precision (RSD 3.46-6.41%), and linearity (r > 0.99) were satisfactory for blood level monitoring and clinical toxicological applications.
Barbiturates↗
Annexins I, II and III are specific choline binding proteins.
We have isolated choline binding proteins from the plasma membrane fraction fraction of human lung epithelium-derived cell line (A549) by means of detergent solubilization, anion exchange and affinity chromatography. One of the affinity purified proteins had a specific choline binding activity of 44-57 pmol/mg, representing a two to three hundredfold enrichment relative to the specific activity of freshly prepared plasma membranes. The purified protein has a molecular mass of 38 kDa by SDS PAGE analysis and was identified as annexin II by N-terminal microsequencing. Annexin II, however, had not previously been known for choline binding activity. We therefore prepared a mixture of authentic annexins (I-V) from A549 cells. The mixture had a choline binding activity of 15 to 18 pmol/mg. The annexin mixture was subsequently affinity chromatographed on the choline-conjugated Sepharose 6B column. Analyses by SDS PAGE and immunoblot revealed that annexins I, II, and III are bound to the choline column while annexins IV and V did not. These results indicate that some of the annexins have specific choline binding activities.
Amino Acid Sequence↗
An intramolecular disulfide bond is essential for annexin I-mediated liposome aggregation.
Dithiothreitol (DTT) inhibits the annexin I-mediated aggregation of phosphatidylserine (PS) liposomes, but has no effect on its binding to PS vesicles. Non-reducing SDS gel analysis indicates that intermolecular disulfide bonds between annexin I molecules are not involved in liposome aggregation. However, DTT causes changes in protein conformation of annexin I as monitored by hydrophobic fluorescent dye treatment. The results suggest that the reduction of the intramolecular disulfide bond leads to inhibition of annexin I-mediated liposome aggregation via protein conformational changes.
Animals↗
Regulation of annexin I by proteolysis in rat alveolar epithelial type II cells.
Limited proteolysis of annexin I occurs endogenously in intact rat lung alveolar epithelial type II cells as revealed by immunoblot analysis. Proteolysis increases in the presence of phorbol 12-myristate 13-acetate (PMA), terbutaline, or ATP, agents that enhance secretion of lung surfactant from type II cells. Calpain, a calcium-dependent neutral protease, was activated in stimulated type II cells and cleaved purified annexin I at the N-terminus minus 26 amino acids. Liposome aggregation activity of truncated annexin I showed ten-fold increase in calcium sensitivity compared to the native form. The results suggest that proteolytic modification may be a regulatory mechanism for annexin I to mediate the secretory processes of alveolar type II cells at physiological calcium concentrations.
Adenosine Triphosphate↗
[Dynamics of IL-2 and IFN-gamma levels induced by sea or Con A in spleen cells of Schistosoma japonicum-infected mice].
The capacity of mitogen Con A and SEA-stimulated spleen cells to produce cytokines IFN-gamma and IL-2 was studied in S. japonicum-infected mice every two weeks from 0 to 14 wk after infection. The results showed that the levels of these two cytokines began to rise at the 4th wk after infection and reached a peak level at 6-8 wk, then declined to the levels similar to those pre-infection at 12-14 wk after infection. The IFN-gamma level reached the peak earlier than the IL-2 level. The dynamics of cytokine level in both mitogen and antigen-stimulated group was similar. The results suggest that IL-2 and IFN-gamma might be the essential cytokines involved in egg granuloma formation in schistosomiasis japonica.
Animals↗
BDNF and NT-4/5 exert neurotrophic influences on injured adult spinal motor neurons.
Adult motor neurons, like their immature antecedents, express the mRNA for the signaling receptor for brain-derived neurotrophic factor (BDNF) and for neurotrophin-4/5 (NT-4/5). However, while both BDNF and NT-4/5 support the survival of axotomized developing spinal motor neurons in vitro or in vivo, it is not known whether these factors continue to influence spinal motor neurons in adulthood. The present study tests if BDNF or NT-4/5 modulate the reactive responses of adult spinal motor neurons to nerve injury. We utilize sciatic nerve transection to axotomize the spinal motor neurons that form the retrodorsal lateral nucleus (RDLN) and show that, after axotomy, RDLN motor neurons lose ChAT immunoreactivity and also reexpress p75Ingfr, the low affinity receptor for all neurotrophin family members. Treatment with BDNF or NT-4/5 alters these effects of sciatic nerve transection. Both BDNF and NT-4/5 attenuate the loss of ChAT expression in axotomized RDLN motor neurons; thus, as compared to vehicle treatments, BDNF and NT-4/5 produce statistically significant increases in the optical density of ChAT immunostaining. Furthermore, BDNF and NT-4/5 also significantly increase the RDLN reexpression of p75Ingfr after sciatic nerve transection. Interestingly, essentially identical increases in RDLN ChAT and p75Ingfr immunostaining are produced by sciatic nerve crush injuries in the absence of exogenous neurotrophin treatment. These data show that treatment with exogenous BDNF and NT-4/5 changes the response of adult spinal motor neurons to sciatic nerve transection. Furthermore, these neurotrophins elicit reactive responses in axotomized motor neurons that mimic those produced by endogenous agents in regenerating crushed peripheral nerve.
Animals↗
Three-dimensional structure of CA1 pyramidal cells in rat hippocampus--optical recording of LSM and computer simulation of fractal structure.
The optical recording of three-dimensional (3-D) reconstruction of CA1 pyramidal cells was derived from the studies on the CA1 region of the hippocampus in adult male Wistar rats. The recording was produced by the Confocal Laser Scan Microscope (LSM-10). The attemption was to outline the morphological neural network of CA1 pyramidal cells organization, following the trail of axo-dendritic connections in 3-D spatial distributions among neurons. The fractal structure of neurons with their dendritic and axonal trees using fractal algorithm was noticed, and 2-18 simulated cells were obtained using PC-486 computer. The simulational cells are similar in morphology to the natural CA1 hippocampal pyramidal cells. Therefore, the exploitation of an advanced neurohistological research technique combining optical recording of the LSM-10 and computer simulation of fractal structure can provide the quantitative fractal structural basis for chaosic dynamics of brain.
Animals↗