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Biomedical subjects

C Luo

Publications and source records attributed to C Luo.

At least 91 records · Page 5Linked to original sources
PubMed1999

[The relationship between the expression of transferrin receptors (TfR) on leukemia cells and the cell proliferation and iron metabolism status in childhood acute leukemias].

OBJECTIVE: To explore the relationship between transferrin receptor (TfR) expression and cell proliferation capacity and iron metabolism status. METHODS: The binding site numbers and dissociation constant (Kd) of TfR of leukemic cells were assayed by radio-ligand binding assay. RESULTS AND CONCLUSION: The binding site numbers of TfR were (7.826 +/- 6.054) x 10(4) sites/cell in ALL group and (20.406 +/- 17.876) x 10(4) sites/cell in AML group, and the Kds of TfR were (6.468 +/- 4.777) nmol/L and (8.683 +/- 4.890) nmol/L, respectively. The binding sites of TfR were significantly less in complete remission group than in relapsed or dead groups. There was a positive relationship between the TfR binding sites and the 3H-TdR incorporation in the leukemic cells (AML and ALL) and in the phytohemagglutinin stimulated peripheral mononuclear cells. In both ALL and AML group, the SF, CF were higher and Tf, TIBC were lower than those in control group. TfR binding sites were positively correlated with SF and CF, and negatively with Tf.

Adolescent↗
PubMed1999

[Clinical and experimental study of jianruling in treating hyperplasia of mammary gland].

OBJECTIVE: To observe the therapeutic effect of Jianruling (JRL) on hyperplasia of mammary gland (HMG) and to explore its mechanism in regulating sex hormones. METHODS: Clinical changes of HMG were observed and serum sex hormones measured before and after JRL treatment. In experimental study, the effect of JRL was estimated by using electron microscope, pathologic and radioimmunoassay. RESULTS: JRL could not only cure HMG, but also regulate the sex hormone secretion both in HMG patients and in rats. Clinical study showed that the clinical cure rate was 72.5%, and the total effective rate was 90.8%, it demonstrated a significant difference in comparing with the control group, P < 0.01. The estradiol and prolactin levels of patients lowered significantly after JRL treatment, P < 0.05, while progestogen and testosterone increased significantly, P < 0.05, but no significantly change of follicle-stimulating hormone and luteinizing hormone was found. JRL showed marked effect in treating and preventing experimental HMG in rats, it could modulate the secretive function of sex hormone, and improve the construction of mammary gland. CONCLUSION: JRL has significant effect in treating HMG, it can adjust the endogenous sex hormone level, delay the development of chronic cystic hyperplasia of mammary gland.

Adolescent↗
PubMed1999

[The detection and its clinical significance of cancer cells in portal vein blood of patients with colorectal carcinoma].

OBJECTIVE: To study the relation between cancer cells in portal vein blood and liver metastasis of colorectal carcinoma. METHODS: The presence of CK20 mRNA was investigated by non-isotope RT-PCR in 54 cases. RESULTS: The positive rate of CK2O mRNA in portal vein blood was 75.9%. The positive cases were significantly correlated with Dukes stage and live metastasis. There was a higher probability of liver metastasis in positive cases after operation. CONCLUSIONS: The detection of CK20 in portal vein blood may improve the accuracy of clinical staging and diagnose liver micrometastasis of colorectal carcinoma.

Biomarkers, Tumor↗
PubMed1999

[Chemotherapeutic failure in micrometastasis in peripheral blood of patients with colorectal carcinomas].

OBJECTIVE: To study chemotherapeutic failure in the micrometastasis in peripheral blood of patients with colorectal carcinomas and its clinical significance. METHODS: We investigated the changes of micrometastasis in peripheral blood of patients with colorectal carcinomas before and after chemotherapy. RESULTS: The positive rate of CK2O mRNA in peripheral blood was 58.3%. Five more positive cases were detected 3 days after operation than before operation. After early short-term chemotherapy following operation, 22 cases turned to be negative. The maintaince of micrometastasis in peripheral blood after chemotherapy was significantly related to bcl-2 expression and p53 mutation in cancer tissues. CONCLUSIONS: The early short-term chemotherapy after operation plays a role in controlling the micrometastasis of colorectal carcinoma. The study of chemotherapeutic effect on micrometastasis in peripheral blood and its relation with the related genes may contribute to the selection of drugs and plans of adjuvant treatment.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1999

[Internal fixation for zygomatic arch fracture with super-high molecular weight poly D, L-lactic acid mini-plates and screws: a study in dogs].

OBJECTIVE: To investigate the internal fixation effects of super high molecular weight (Mv = 6.0 x 10(5) kD) poly D, L-lactic acid(PDLLA) mini-plates and screws. METHODS: 10 dogs were utilized in this experiment with the self-contrast study method, comparing with the titanium mini-plates and screws. RESULTS: The mechanical properties of the PDLLA mini-plates and screws appeared to be sufficient to enable undisturbed healing of depressed zygomatic arch fracture. CONCLUSION: The good fixation effect of PDLLA mini-plates and screws was as same as that of the titanium mini-plates and screws without the need of secondary operation.

Animals↗
PubMed1999

[Tissue reaction and degradation of super-high molecular weight poly D, L-lactic acid mini-plates and screws: an animal experiment].

OBJECTIVE: To investigate the tissue reaction and degradation processes of the super-high molecular weight(Mv = 6.0 x 10(5) kD) poly D, L-lactic acid(PDLLA) mini-plates and screws through the internal fixation for zygomatic arch fracture. METHODS: It was carried out by the self-contrast study method and comparing with the titanium mini-plates and screws. RESULTS: There was no side-effects on bone healing. The reaction of soft and hard tissues to PDLLA mini-plates and screws was similar to that of the titanium mini-plates and screws. No complication had been seen with the use of PDLLA mini-plates and screws, including infection, foreign body reaction and underlying osteolysis. The PDLLA devices had no changes in shape after 3 months, and then became the grains in different sizes after 6 months, and were completely resorbed within 12 months in vivo. CONCLUSION: The super-high molecular weight PDLLA mini-plates and screws has good biocompatibility and proper degradation time. It is safe and effective to use the mini-plates and screws made of the super-high molecular weight PDLLA for internal fixation of bone.

Animals↗
PubMed1999

[The spectral study of the surface modified medical rubber].

In this article ,the drug-resistance of two kinds of medical rubber whose surfaces have been modified were investigated by ATR-FTIR and XPS. The experimental results show that the compositions of the two samples'surface and body are different. The surface is fluorinated rubber although the body is butyl rubber. The ratio of fluorine to carbon atom in sample Ii -1 is higher than that in sample I -1. The principal join between F and C is the form--CF2--in sample II -1,but in sample I -1 it is the form--CF2-- and--CHF--. The change for F/C of the different depth in sample II- 1 was relatively less than that in sample I -1 when they were etched by argon ion bundle in the same conditions.

Drug Packaging↗
PubMed1998

Spatial and temporal expression of c-Fos protein in the spinal cord of anesthetized rat induced by subcutaneous bee venom injection.

In order to study central neuronal components involved in subcutaneous (s.c.) bee venom-induced persistent pain (a new tonic pain model), we use Fos immunostaining technique to study the spatial and temporal patterns of neuronal activity in the spinal cord of anesthetized rats. Following intraplantar bee venom injection, Fos-like immunoreactive (ir) neurons were only seen from L1 to S3 rostrocaudally with distinct distribution at L4-5 segments. At segments of L1-2 and S1-3, Fos-ir labelings were diffusely and symmetrically distributed on both sides of the gray matter; however, at L4-5 segments, Fos-ir neurons were densely localized in medial portion of laminae I-II, less densely in laminae V-VI and a few in laminae VII and X ipsilateral to the injection side. No Fos labeling was seen in ventral horn of the spinal cord at L4-5 segments. Fos protein began to express only within lamina I at 0.5 h, but increased over the whole dorsal horn at 1 h and reached peak labeling at 2 h after bee venom. Expression of c-Fos in laminae I-II decreased at 4 h, and completely disappeared at 24 h, however, labeling in laminae V-VI disappeared much slowly and existed even at 96 h after bee venom. Within laminae III-IV, Fos-ir neurons could not be seen at 0.5 h, but began to be seen at 1 h and appeared to exist even at 24 h after bee venom. Systemic morphine suppressed c-Fos expression dose-dependently in both superficial and deep layers of dorsal horn and the latter region was much more sensitive to morphine than the former one. The present results demonstrated that prolonged neuronal activities in superficial and deep layers of dorsal horn were essential to mediation of bee venom induced tonic pain and may have different roles in generation and/or modulation of spontaneous pain and hyperalgesia and allodynia.

Analgesics, Opioid↗
PubMed1998

Cell fusion studies to examine the mechanism for etoposide resistance in Chinese hamster V79 spheroids.

When exposed to etoposide, the outer cells from Chinese hamster V79 spheroids are about 10 times more resistant to DNA strand breaks and cell killing than V79 cells grown as monolayers. Previous results have shown that the outer cells of both spheroids and monolayers grow at the same rate and contain the same amount and activity of the target enzyme, topoisomerase II. In order to examine possible mechanisms for this resistance, cell fusion studies were conducted with fluorescent dye-tagged monolayer and spheroid cells. Fused cells were exposed for 30 min to 1.2 microg/ml etoposide and then separated using fluorescence-activated cell sorting into binucleate cells consisting of two monolayer cells, two spheroid cells, or a mixed doublet consisting of one cell of each type. Individual sorted cell doublets were examined for the presence of etoposide-induced DNA strand breaks using the alkaline comet assay. As expected, doublets of monolayer cells were sensitive to etoposide and doublets of spheroid cells were resistant. However, mixed doublets were as resistant to DNA damage by etoposide as spheroid doublets. In comparison, when etoposide- or adriamycin-resistant V79 monolayer cells were fused to the parent monolayer cells, the expected intermediate sensitivity to etoposide was observed for the mixed doublets. We conclude that etoposide resistance associated with the outer cells of spheroids can be "transferred" to produce resistance in monolayer cells. Rapid changes in phosphorylation that can affect topoisomerase II activity or localization, or that can alter chromatin structure, are suggested as possible mechanisms of resistance. In support of this hypothesis, topo IIalpha phosphorylation was at least 10 times greater in monolayers than in the outer cell layer of spheroids.

ATP Binding Cassette Transporter, Subfamily B↗
PubMed1998

Nuclear localization is required for function of the essential clock protein FRQ.

The frequency (frq) gene in Neurospora encodes central components of a circadian oscillator, a negative feedback loop involving frq mRNA and two forms of FRQ protein. Here we report that FRQ is a nuclear protein and nuclear localization is essential for its function. Deletion of the nuclear localization signal (NLS) renders FRQ unable to enter into the nucleus and abolishes overt circadian rhythmicity, while reinsertion of the NLS at a novel site near the N-terminus of FRQ restores its function. Each form of FRQ enters the nucleus soon after its synthesis in the early subjective day; there is no evidence for regulated sequestration in the cytoplasm prior to nuclear entry. The kinetics of the nuclear entry are consistent with previous data showing rapid depression of frq transcript levels following the synthesis of FRQ, and suggest that early in each circadian cycle, when FRQ is synthesized, it enters the nucleus and depresses the level of its own transcript.

Biological Clocks↗
PubMed1998

Anti-BSA antibodies do not cross-react with the 69-kDa islet cell autoantigen ICA69.

In contrast to several previously published reports, we demonstrate by a variety of antibody assays that bovine serum albumin (BSA) is not antigenically cross-reactive with the 69-kDa islet cell autoantigen (ICA69). Fast protein liquid chromatography purified BSA and highly purified recombinant human ICA69 were used to establish sensitive Western blot and ELISA assays in order to detect antibodies against these two proteins. The assays excluded BSA or powdered milk as blocking agents, since these would interfere with antibody binding. A panel of sera from diabetic individuals, first degree relatives, and normal controls showed that the majority (approximately 70%) of individuals from each group had antibodies against ICA69 as assayed by Western blots, whereas considerably fewer (approximately 13%) had anti-BSA antibodies on Western blots, and individuals with antibodies to both proteins occurred only rarely (2-3%). To explore this issue further we immunized a total of 16 individual rats, representing four different strains (bio-breeding diabetes resistant and diabetes prone, Wistar-Furth, and Sprague-Dawley), with either BSA (n = 2 of each strain) or with recombinant ICA69 (n = 2 of each strain), and for each animal pre- and postimmune antibody titres against BSA and against ICA69 were assayed separately by enzyme-linked immunoabsorbent assay. In rats immunized with BSA, anti-BSA titres increased about 100,000-fold over preimmune levels, whereas anti-ICA69 reactive antibodies were unchanged over preimmune levels. Similarly, in rats immunized with ICA69, anti-ICA69 titres rose about 100,000-fold over preimmune levels, whereas anti-BSA antibodies were unchanged over preimmune levels. Thus we find no evidence for the existence of antibody cross-reactivity between ICA69 and BSA, either in humans or in immunized rats. When our rat anti-BSA antisera were used to probe Western blots made from rat islets isolated in the strict absence of fetal calf serum, we were unable to detect a 69-kDa band, even when the islets were preincubated with gamma-interferon, a treatment which has been reported to induce the BSA cross-reactive islet antigen. We conclude that BSA is not antigenically cross-reactive with ICA69 at the antibody level, and it is highly unlikely that BSA is antigenically cross-reactive with some other 69 kD islet cell antigen.

Animals↗
PubMed1998

Bilateral testicular tumors in an infant.

A 7-month-old infant showed bilateral enlarged, nontender scrotal masses. The level of alpha-fetoprotein was greater than 10,000 ng/ml preoperatively; a high left inguinal orchiectomy was performed for a suspected yolk-sac tumor. The right testis was diagnosed as a mature teratoma because it was not possible to establish a line of cleavage between the tumor and the normal tissue, and a high right inguinal orchiectomy was performed. Only one case of bilateral testicular teratomas has been reported in the literature to date. We report a rare second case of bilateral testicular tumors, one a yolk-sac tumor and the other a teratoma.

Endodermal Sinus Tumor↗
PubMed1998

The contribution of spinal neuronal changes to development of prolonged, tonic nociceptive responses of the cat induced by subcutaneous bee venom injection.

To elucidate neurophysiological mechanisms of persistent pain induced by tissue injury, the present study was designed to investigate the effects of s.c. bee venom injection on responses of the dorsal horn nociceptive neurons and those of behavior in anesthetized and awake cats, respectively. A parallel comparative study was also performed to compare the effects of s.c. bee venom and formalin injections on neuronal responses by using an extracellular single-unit recording technique. The present results showed that s.c. bee venom injection into the peripheral cutaneous receptive field resulted in a protracted, tonic monophase of increase in spike responses of wide-dynamic-range (WDR) neurons for more than 1 h, while injection of the same volume of vehicle did not have such an effect. The mean number of spikes during the 60-min period after bee venom was 6.74+/-2.58 spikes/s (n=10), which showed a significant increase in firing rate over the background activity (2.23+/-0.96 spikes/s). Behavioral observations showed that s.c. bee venom injection into the dorsum of a hind paw also produced a prolonged, tonic single phase of response indicative of pain, suggesting that central neuronal changes may contribute to development of bee venom-induced prolonged, tonic pain in cats. The increased neuronal firing induced by s.c. bee venom could be suppressed by a single dose of i.v. morphine and resumed by naloxone. Blockade of the sciatic nerve with lidocaine resulted in a complete suppression of the bee venom-induced neuronal firing, suggesting that the central neuronal changes following s.c. bee venom are peripherally-dependent. Comparative studies showed that the duration and frequency of the bee venom-induced neuronal responses were comparable to those induced by s.c. formalin; however, responses of WDR neurons to mechanical stimuli applied to the injection site of the two chemical agents were quite different. Bee venom produced a significant enhancement of mechanical responses of WDR neurons, while, on the contrary, formalin produced a desensitization of sensory receptors in the injection site, suggesting that the two tonic pain models may have different underlying mechanisms. Copyright 1998 European Federation of Chapters of the International Association for the Study of Pain.

Journal Article↗
PubMed1998

Acceleration of oxime-induced reactivation of organophosphate-inhibited fetal bovine serum acetylcholinesterase by monoquaternary and bisquaternary ligands.

Reactivation of organophosphate (OP)-inhibited acetylcholinesterase (AChE) by oximes is the primary reason for their effectiveness in the treatment of OP poisoning. Reactivation is reported to accelerate by quaternary ligands such as decamethonium, which is devoid of nucleophilicity. The mechanism of this enhancement is not known. To better understand the acceleration phenomenon, we examined ligand modulations of oxime-induced reactivation of methylphosphonylated AChE using 7-(methylethoxyphosphinyloxy)-1-methylquinolinium iodide and fetal bovine serum AChE. Edrophonium, decamethonium, and propidium, three quaternary AChE ligands of different types, were tested as potential accelerators. Experiments were carried out with both soluble enzyme preparation and AChE conjugated to polyurethane. Kinetic measurements with oximes 2-[hydroxyiminomethyl]-1-methylpyridinium chloride, 1,1'-trimethylene bis-(4-hydroxyimino methyl)-pyridinium dibromide, and 1, 1'-[oxybis-methylene)bis[4-(hydroxyimino)methyl]pyridiniu um dichloride showed that in the presence of 50 microM edrophonium, the reactivation rate constants increased 3.3-12.0-fold; 200 microM decamethonium produced a 1.6-3.0-fold enhancement of reactivation rate constants by the same oximes. Reactivation of the inhibited enzyme by 1-(2-hydroxyiminomethyl-1-pyridinium)-1-(4-carboxy-aminopyridinium )-d imethyl ether hydrochloride, 1-(2-hydroxyiminomethyl-1-pyridinium)-1-(3-carboxy-aminopyridinium )-d imethyl ether hydrochloride, and 1-[[[4-(aminocarbonyl)pyridino]methoxy]methyl]-2, 4, -bis(hydroxyimino)methyl pyridinium dichloride was not affected by either ligand. Propidium slowed the reactivation of 7-(methylethoxyphosphinyloxy)-1- methylquinolinium iodide-inhibited AChE by all oximes. Results suggest that the accelerator site may reside inside the catalytic gorge rather than at its entrance and acceleration may be due to the prevention of reinhibition of the regenerated enzyme by the putative product, the phosphonylated oxime. In addition to the nucleophilic property of the oximate anion, some of the reactivators may carry an accelerating determinant, as characterized with respect to edrophonium and decamethonium. Results offer possible explanations for the superiority of 1-(2-hydroxyiminomethyl-1-pyridinium)-1-(4-carboxy-aminopyridinium )-d imethyl ether hydrochloride over other oximes in the reactivation of specific AChE-OP conjugates.

Acetylcholinesterase↗
PubMed1998

[Expression of CD44 molecule and its significance in uveal and conjunctival melanomas].

The aim of this study was to evaluate the role of over expression of CD44 molecule in the development and progression of uveal and conjunctival melanomas. Flow cytometry (FCM) and immunofluorescence methods were used for detecting the CD44V expression in uveal malignant melanomas (UMM), conjunctival nevi (CN) and conjunctival malignant melanomas(CMM). The expression content of CD44 in 7 cases of CMM was significantly higher than that in 5 cases of CN (P < 0.05); the CD44V positive expression percentages in 7 cases of CMM and 40 cases of UMM were 71.43% and 62.50% respectively; the expression content of CD44V in UMM was related to scleral invasion (P = 0.0105); there was a negative correlation between the expression content of CD44V and proliferative index (PI), S-phase fraction (SPF) (P < 0.01; P < 0.05). The results suggested that the over expression of CD44V might be involved in the development of CMM and UMM and related to local infiltration ability of UMM and that the CD44V expression content detected by FCM might be helpful in discriminating CN From CMM, but this waited for further research confirmation.

Conjunctival Neoplasms↗
PubMed1998

Pericardial devascularization combined with Latarjet's innervation in the treatment of patients with portal hypertension.

OBJECTIVE: To study the effect of pericardial devascularization combined with Latarjet's innervation on portal hypertension. METHODS: Forty-eight patients undergoing pericardial devascularization combined with Latarjet's innervation were compared with 57 patients with devascularization. Clinical results were evaluated by postoperative portal vein pressure, postoperative rebleeding, operative mortality, abdominal distension, sudden diarrhea, and gastric retention. RESULTS: The incidence of rebleeding, mortality, abdominal distension, sudden diarrhea, and gastric retention was 2%, 6.3%, 6.3%, 4.2% and 0% respectively in pericardial devascularization combined with Latarjet's innervation, and 12.5%, 12.3%, 24.6%, 15.6% and 14% respectively in devascularization. CONCLUSIONS: Pericardial devascularization combined with Latarjet's innervation preserves the normal function of gastric emptying. This method plays an important role in maintaining nutritional supply and digestive function.

Adult↗
PubMed1997

Evaluation of combined toxic effects of GB/GF and efficacy of jielin injection against combined poisoning in mice.

A computer program (Q-test) was used to evaluate the combined toxic effects of nerve agent GF and its combined form with sarin (GB/GF) in mice. Efficacy of Jielin Injection, the 2-PAM-containing antidote used successfully in China for the treatment of organophosphate pesticide poisoning, was also evaluated and compared with HI-6 against single and combined poisonings. The two agents were basically additive in toxicity when combined. However, toxic signs (convulsions) appeared later in combined poisoning than after exposure to each agent alone. The protective ratio of Jielin Injection against GF poisoning was low but significantly higher when against poisoning by GB or combined agent. When HI-6 was substituted for 2-PAM, the antidote was more effective against poisoning by both single and combined agents. Results of in vitro reactivation of GF-inhibited human erythrocyte acetylcholinesterase by these oximes agreed with the in vivo antidotal efficacy.

Animals↗