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Biomedical subjects

L Guo

Publications and source records attributed to L Guo.

At least 271 records · Page 15Linked to original sources
PubMed1995

Phenotypes of dnaA mutants of Escherichia coli sensitive to detergents and organic solvents.

We examined growth sensitivities of dnaA mutants of Escherichia coli to detergents (deoxycholic acid, cholic acid) and organic solvents (ethanol, glycerol). The dnaA602, dnaA604, dnaA5, and dnaA46 mutants with mutations in the putative ATP binding site of DnaA protein showed higher sensitivities to the detergents than did the wild-type strain. The dnaA508 and dnaA167 mutants with mutations in the N-terminal region of DnaA protein, however, showed higher sensitivities to organic solvents. The dnaA204 and dnaA205 mutants with a mutation in the C-terminal region of DnaA protein showed similar sensitivity as did the wild-type strain to reagents. Complementation analysis with a plasmid carrying the wild-type dnaA gene confirmed that dnaA mutations are responsible for these phenotypes that are sensitive to the reagents.

Bacterial Proteins↗
PubMed1995

Identification and quantitation of choline glycerophospholipids that contain aldehyde residues by fluorometric high-performance liquid chromatography.

A high-performance liquid chromatographic method was established for the fractionation of oxidized choline glycerophospholipids (CGPs) that contain aldehyde residues, after their derivatization with a fluorescent reagent 4-(N,N-dimethylaminosulfonyl)-7-hydrazino-2,1,3-benzoxadiazole (DBD-H). DBD-H efficiently reacted with the aldehyde residues of phospholipids at room temperature. Fluorescent derivatives of aldehydic phospholipids were well separated into species that contained aldehyde groups at different sites. The relationship between the amount of each derivative and the signal was linear over a wide range and amounts as low as several picomoles of aldehydic CGP could be detected. This method is applicable to the quantitation of aldehydic phospholipids in peroxidized membranes of red blood cells. In the present study, formation of aldehydic choline glycerophospholipids was demonstrated for the first time in peroxidized red blood cell membranes and the compounds were quantitated.

Aldehydes↗
PubMed1995

Gene targeting of BPAG1: abnormalities in mechanical strength and cell migration in stratified epithelia and neurologic degeneration.

BPAG1 is the major antigenic determinant of autoimmune sera of bullous pemphigoid (BP) patients. It is made by stratified squamous epithelia, where it localizes to the inner surface of specialized integrin-mediated adherens junctions (hemidesmosomes). To explore the function of BPAG1 and its relation to BP, we targeted the removal of the BPAG1 gene in mice. Hemidesmosomes are otherwise normal, but they lack the inner plate and have no cytoskeleton attached. Though not affecting cell growth or substratum adhesion, this compromises mechanical integrity and influences migration. Unexpectedly, the mice also develop severe dystonia and sensory nerve degeneration typical of dystonia musculorum (dt/dt) mice. We show that in at least one other strain of dt/dt mice, BPAG1 gene is defective.

Animals↗
PubMed1995

Neutrophil elastase inhibitor (ONO-5046) prevents lung hemorrhage induced by lipopolysaccharide in rat model of cerulein pancreatitis.

The protective effects of a neutrophil elastase inhibitor (ONO-5046) on cerulein-induced pancreatitis followed by a septic challenge with intraperitoneal lipopolysaccharide (LPS) were studied in a rat model. Pancreatitis was induced by four intramuscular injections of cerulein (50 micrograms/kg at 1-hr intervals). ONO-5046 was administered by continuous intravenous infusion via the right jugular vein (50 mg/kg/hr, 30 min prior to the first cerulein injection to 20 hr following the last cerulein injection). Significant differences in serum amylase and pancreatic wet weight ratio were not observed between the animals with pancreatitis treated with or without ONO-5046. There was no significant difference in the in vitro tumor necrosis factor-alpha (TNF-alpha) production by peritoneal macrophages from rats with pancreatitis treated with or without ONO-5046. In a second experiment, LPS (10 mg/kg) was administered intraperitoneally as the septic challenge 6 hr following the first cerulein injection. Lung hemorrhage was seen in the animals with pancreatitis untreated with ONO-5046 24 hr following the first cerulein injection. No significant lung hemorrhage was observed in the animals with pancreatitis treated with ONO-5046 administering 30 min prior to the first cerulein injection. These results suggest that lung hemorrhage in cerulein-induced pancreatitis that follows a septic challenge with LPS can be prevented by the intravenous administration of ONO-5046. Thus there is a significant role for neutrophil elastase in pancreatitis-associated lung injury.

Animals↗
PubMed1995

Preferential formation of the hydroperoxide of linoleic acid in choline glycerophospholipids in human erythrocytes membrane during peroxidation with an azo initiator.

The formation of phospholipid hydroperoxides was monitored in human red blood cell (RBC) membranes that had been peroxidized with an azo initiator. Peroxidation of RBC membranes caused a profound decrease in the amount of polyunsaturated fatty acids and concomitantly hydroperoxides, as primary products of peroxidation, appeared in the phospholipids. Hydroperoxides were predominantly generated in choline glycerophospholipid (CGP), while the extent of formation of ethanolamine glycerophospholipid (EGP) hydroperoxides was low and their presence was transient. Hydroxy and hydroperoxy moieties in CGP were identified as 9-hydroxy and 13-hydroxy octadecanoic acid, derived from linoleic acid, by gas chromatography-mass spectrometric analysis. No consistent generation of hydroperoxide from arachidonic acid was evident in CGP. The CGP-hydroperoxide accounted for approximately 76% of linoleic acid consumed during peroxidation of RBC membranes. The prominent generation of phospholipid hydroperoxides was observed in the linoleic acid-rich membranes from rabbit RBC, indicating that the level of linoleic acid in phospholipids determines, in part, the extent of formation of phospholipid hydroperoxides. Aldehydic phospholipids, as secondary products of peroxidation, were detected in oxidized membranes. EGP was the most prominent aldehydic phospholipid, while negligible amounts of aldehydic CGP were formed. This study indicates that the process of oxidation of individual phospholipids clearly differs among phospholipids and depends on the structure of each.

Adult↗
PubMed1995

A mathematical lifting model of the lumbar spine.

The objective of this study was to develop a comprehensive mathematical lifting model which takes into account both task and personal factors. The outcome measure of this model was compared to that of the 1981 and 1991 NIOSH lifting equations as well as the model reported by Drury and Pfeil (Int J Prod Res 13:137, 1975). The model was developed in two stages. In the first stage, the complete model was derived from the psychophysical data. In the second stage, the discounting factors of the various parameters included in the model were tested and adjusted using the physiological and biomechanical data. The rationale for building the model in two stages was based upon the hypothesis proposed and tested by Karwowski (Proc Ergon Soc Conf 95, 1983), which, combining the acceptability of physiological and biomechanical stresses, should lead to an overall measure of lifting task acceptability--namely, the acceptability of psychophysical stress. The following input parameters were incorporated into the model: (a) horizontal distance in the sagittal plane, (b) vertical distance between the origin of lift and the floor, (c) vertical travel distance, (d) lifting frequency, (e) task duration, (f) twisting angle, (g) coupling, (h) heat stress, (i) gender, (j) age, (k) body weight, and (l) percentage of worker population. The lifting capacity values predicted from the present study are consistently lower than the values generated from prior research. This can largely be explained by the incorporation of new biomechanical and physiological guidelines for lifting tasks.

Aging↗
PubMed1995

[A comparative morphologic study of Carabelli cusp between Chinese and Japanese students.].

The study of teeth,dentition and occlusion is helpful to guide oral medical clinic and the study of anthropology.Our department of Osaka Dental University and had many items of research work about teeth,dentition and occlusion between Chinese and Japanese students.This article reports the study of Carabelli cusp.The results revealed:(1)the rate of Carabelli cusp is higher in Japanese than in Chinese and is higher in male than in female.(2)the rate of Carabelli cusp of the first maxillary molar of both side is very high.(3)The rate of Carabelli cusp is related to the height and the type of cusp numbers.These all illustrated the occurence of Carabeiil cusp were influenced by race, individual and the development of teeth.

English Abstract↗
PubMed1995

[Apoptosis of tumor cells in lectin-dependent lymphokine-activated killer cell-mediated cytotoxicity].

By using DNA electrophoresis and propidium iodide (PI) staining flow cytometry (FACS) analysis, we studied the mechanisms of lymphokine-activated killer (LAK) cell-mediated cytotoxicity. In the presence of pokeweed mitogen (PWM), human LAK cells induced DNA fragmentation of two leukemic cell lines (U937 cells and Raji cells) and two solid tumor cell lines (SW1116 cells and Hep-2 cells), a hallmark of apoptosis. The reactions were carried out at the effector/target ratio of 1:1 and in 4 hr coculture. Pretreatment with RNA and protein synthesis inhibitors (actinomycin D and cycloheximide) did not prevent the target cells from apoptosis. As the TNF-resistant tumor cell lines such as SW1116 cells and Raji cells were also triggered to apoptosis, other factors than TNF would play the role. DNA-PI staining FACS analysis also suggested that a part of LAK cells underwent apoptosis to some extent during incubation with target cells. The results provide a new way to investigate the mechanisms of cytotoxicity of LAK cells and to enhance the efficacy of adoptive tumor therapy with LAK cells.

Apoptosis↗
PubMed1995

[The effects of 2-chloro-4-bromo-alpha-methylcinnamic acid on the neuromuscular transmission of toad].

The effects of 2-chloro-4-bromo-alpha-methylcinnamic acid sodium (SC1001 Na) on neuromuscular transmission were tested by means of intracellular recordings in isolated sciatic nerve-sartorius preparations of toad. The results were: (1) at a concentration of 0.1mmol/L, SC1001 Na had no effect on end-plate potential (EPP); at a concentration of 1 mmol/L, SC1001 Na reduced the amplitude of the EPP significantly, and the paired-pulse facilitation was also decreased; at a concentration of 10mmol/L, SC1001 Na blocked the EPP completely; (2) the 0.1 mmol/L and 1mmol/L groups of drug had no effect on the resting potential of the toad muscle fibers; the resting potential was reduced significantly by SC1001Na at the concentration of 10mmol/L, the action of 10mmol/L drug was irreversible. These results suggest that SC1001 Na may block the neuromuscular transmission of toad, and the blocking effect might be mainly due to a presynaptic mechanism.

Animals↗
PubMed1995

[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↗
PubMed1995

[Preliminary study on the anti-tubercular effect of Ottelia alismoides (L.) Pers].

In clinical trials, the extract of Ottelia alismoides cured two cases of bilateral tuberculosis of cervical lymph gland within 3 months. The result of drug sensitive test showed that water extract of this herb could kill or inhibit human tubercular bacteria effectively, which suggests that Ottelia alismoides is a promising medicinal herb with anti-tubercular effect.

Antitubercular Agents↗
PubMed1995

[Flow cytometry used to distinguish between complete and partial hydatidiform moles].

The nuclear ploidy of 14 placentas was determined by flow cytometry. All histologically classified complete moles (4 cases), hydropic villi (4 cases) and control placentas (3 cases) were diploid; whereas two of three histologically classified partial moles were triploid. The remaining case classified as partial mole was diploid, most likely a complete mole. It was concluded that DNA flow cytometric analysis offers an informative supplement to the histological interpretation of hydropic placentas.

DNA, Neoplasm↗
PubMed1995

[Overexpression of p53 in transitional cell carcinoma of the ovary].

To determine the prevalence of p53 abnormal protein expression in transitional cell carcinoma of the ovary in Peking Union Medical College hospital, and to analyse the correlation between the overexpression of p53 protein and prognostic parameters of transitional cell carcinoma of the ovary, thirty-two transitional cell carcinoma of the ovary and 20 normal ovaries were analysed. Detection of overexpression of p53 protein was carried out by immunohistochemical staining (IHS) using the monoclonal antibody DO-1 on paraffin sections. 41% of 32 samples of transitional cell carcinoma of the ovary showed positive IHS with DO-1, whereas only 5% of 20 normal ovaries showed weakly positive cytoplasmic staining (P < 0.01). p53 overexpression did not correlate with age, CA125 levels, histological grade and lymph node metastasis, but patients with overexpression of p53 had a poor prognosis. Overexpression of p53 is a more common event in transitional cell carcinoma of the ovary. Further studies are warranted to clarify the role of p53 in transitional cell carcinoma of the ovary.

Carcinoma, Transitional Cell↗
PubMed1995

[A potentially new sodium channel blocker: 2-chloro-4-bromo-alpha-methylcinnamic acid].

The effects of 2-Chloro-4-Bromo-alpha-Methylcinnamic acid sodium (SC1001 Na) and some channel antagonists on the action potential (AP) and the resting potential (RP) were tested intracellularly in the sartorius muscle of the toad (Bufo bufo gargarizans). TEA (10mmol/L) and MnCl2 (10 mmol/L) had no effect on the amplitude of the AP, otherwise, TTX (1 mumol/L) blocked the AP completely. SC1001 Na at the concentration of 2mmol/L largely decreased the amplitude of the AP and expanded the duration of the AP (measured at 1/2 peak amplitude), but it had no effect on the RP. The effects of ms group of drug were reversible. Under the pretreatment of the muscle preparation with TEA (10 mmol/L), SC1001 Na still increased the duration of the AP while decreased its amplitude. At the concentration of 10mmol/L, SC1001 Na completely blocked AP and depolarized the RP significantly. These effects were not reversible. As the structure of SC1001 Na is different from that of heterocycloguanidine Na channel blocker, such as TTX, or that of local anesthetics, we infer that SC1001 Na may be a new sodium channel blocker.

Action Potentials↗
PubMed1995

[Overexpression of C-erbB3 in transitional cell carcinoma of the ovary].

OBJECTIVE: To determine the prevalence of C-erbB3 abnormal protein expression in transitional cell carcinoma of the ovary in our hospital and to analyse the correlation between the overexpression of C-erbB3 protein and prognostic parameters of transitional cell carcinoma of the ovary. METHODS: Thirty-two transitional cell carcinoma of the ovary and 20 normal ovaries were studied for overexpression of C-erbB3 protein by immunohistochemical staining (IHS), using the monoclonal antibody RJT2 on paraffin sections. RESULTS: Forty seven percent of 32 samples of transitional cell carcinoma of the ovary showed positive IHS with RJT2, and 39% of 20 normal ovaries showed positive cytoplasmic and membrane staining (P > 0.05). C-erbB3 overexpression did not correlate with age, CA125 levels, histological grade and lymph node metastases, but patients with overexpression of C-erbB3 had a poorer prognosis. CONCLUSION: Overexpression of C-erbB3 is a common event in transitional cell carcinoma of ovary. Further studies are warranted to clarify the role of C-erbB3 in transitional cell carcinoma of the ovary.

Carcinoma, Transitional Cell↗
PubMed1995

[A preliminary report on changes in micro-circulation of conjunctiva in patients with high altitude pulmonary edema].

Micro-circulation of conjunctiva was investigated in 36 patients with high altitude pulmonary edema (HAPE) and 21 healthy subjects who arrived recently in high land and were the controls, and plasma angiotensin II (AT II) and aldosterone (ALD) were determined in 16 patients with HAPE and in the control group. The results show that the concentrations of plasma AT II, ALD in patients with HAPE are obviously higher than those of the healthy individuals (P < 0.001), the degree of changes in micro-circulation of conjunctiva in patients with HAPE is directly proportional to the degree of severity of HAPE, and the higher the concentrations of plasma AT II and ALD, the severer the degree of changes in micro-circulation.

Adolescent↗
PubMed1994

The 'pterocarpan synthase' of alfalfa: association and co-induction of vestitone reductase and 7,2'-dihydroxy-4'-methoxy-isoflavanol (DMI) dehydratase, the two final enzymes in medicarpin biosynthesis.

Vestitone reductase and 7,2'-dihydroxy-4'-methoxy-isoflavanol (DMI) dehydratase are the two final enzymes in medicarpin biosynthesis in alfalfa (Medicago sativa). Although two independent enzymes, vestitone reductase and DMI dehydratase can be loosely associated in low ionic strength buffers, presumably by a weak protein-protein interaction. The activities of vestitone reductase and DMI dehydratase increased approximately 3-fold 6 hours after elicitor treatment in alfalfa suspension cell culture. The activities remained at maximal levels for 40 hours, correlating with a steady increase in the medicarpin content of the cells. Medicarpin produced in vitro from vestitone by the action of vestitone reductase and DMI dehydratase was found to be (-)-medicarpin (6aR,11aR-medicarpin), possessing the same stereochemistry as medicarpin produced in vivo.

Anti-Inflammatory Agents, Non-Steroidal↗