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Biomedical subjects

L Cui

Publications and source records attributed to L Cui.

At least 163 records · Page 9Linked to original sources
PubMed1994

Lack of promoting activity of 7-methoxy-2-nitro-naphtho-[2,1-b]furan (R7000) in a medium-term rat liver bioassay.

Among the nitro-naphthofurans, 7-methoxy-2-nitro-naphtho[2,1-b]furan (R7000) has proved to be a very potent mutagen that causes sarcomas at the subcutaneous injection site and carcinomas in the forestomach after p.o. administration. In the present study, possible promoting activity for diethylnitrosamine (200 mg/kg, i.p.)-initiated liver carcinogenesis was assessed in rats. R7000 dissolved in 5% ethanol solution at doses of 10 or 50 mg/l given as the drinking water for 6 weeks did not enhance development of pre-neoplastic glutathione S-transferase placental form positive foci. Thus, it was concluded that R7000 may not be carcinogenic for the rat liver under the present experimental conditions.

Animals↗
PubMed1994

Primary structure and functional characterization of rat C5a: an anaphylatoxin with unusually high potency.

The anaphylatoxin C5a is a pro-inflammatory factor generated from C5 during complement activation. C5a derived from rat C5 exhibits significantly greater potency compared to C5a from other species. Rat C5a was 25-fold more potent than human C5a for eliciting spasmogenic contraction of guinea pig ileum. Proteolytic removal of the C-terminal arginine of C5a (C5adesArg) reduced spasmogenic potency of rat C5a by only 4-fold compared to a 3,000-fold reduction for human C5adesArg. In addition, rat C5adesArg was 50-fold more potent than human C5adesArg in a guinea pig vascular permeability (in vivo) assay and as a chemotactic factor for human neutrophils. C5a and C5adesArg were purified from zymosan-activated rat serum. Rat C5a, like human C5a, is glycosylated but contains 77 amino acid residues instead of the 74 residues of human C5a. Comparison of the primary structures of rat and human C5a indicated differences at 30 positions including an insert of 3 residues (LLH) in the rat molecule between residue positions 3 and 4 in human C5a. Insertion of residues LLH between Gln-3 and Lys-4 in a recombinant human C5a molecule using site-directed mutagenesis failed to enhance potency. Synthetic C-terminal analogues of rat C5a proved to be measurably more potent than the corresponding human C5a analogues (Ember JA et al., 1993, Protein Sci 2(Suppl 1):159 [Abstr]). We conclude that multiple sequence differences in the C-terminal effector portion and/or elsewhere in rat C5a, but not the LLH insert, account for the significant enhancement in potency of rat C5a over C5a from other species.

Amino Acid Sequence↗
PubMed1994

Effect of ethanol on paraquat toxicity in F344 rats.

The potential modifying effects of ethanol and paraquat on lesion development in livers and lungs of male F344 rats were studied. Animals were divided into diethylnitrosamine (DEN)-initiated and non-initiated groups, subgroups of each being exposed to 10 ml 20% ethanol/kg body weight, 2.5 or 10 mg paraquat/kg body weight or a combination of 10 ml 20% ethanol/kg body weight and 2.5 or 10 mg paraquat/kg body weight, given by intragastric intubation three times a week. Controls received 10 ml saline/kg body weight. All animals were subjected to two-thirds partial hepatectomy at the end of wk 3 and killed at the end of wk 8. All five rats receiving 10 mg paraquat/kg body weight without DEN-pretreatment died before termination of the experiment, but the additional ethanol treatment saved animals: only one of five rats died. Rats administered 2.5 or 10 mg paraquat/kg body weight demonstrated lung toxicity, as evidenced by fibrosis and hyperplasia, but not when simultaneously treated with ethanol in DEN-pretreated groups. In the liver, however, evaluation of glutathione S-transferase placental form (GST-P)-positive foci did not reveal any influence of the treatments on lesion development in DEN-initiated animals. It is concluded that ethanol decreases paraquat toxicity, and that neither agent, alone or in combination, exerts any hepatocarcinogenic modification potential.

Animals↗
PubMed1994

[Changes in the contents of plasma SOD and MDA in 50% III degree burn dogs after delayed fluid replacement].

The plasma SOD and MDA content were determined in 50% III degree burn dogs with delayed fluid replacement. The results showed that the activity of plasma total SOD and CuZn-SOD rapidly declined and were obviously lower during the first 5 days postburn than preburn values, while the content of Mn-SOD did not show significant change. The plasma MDA was evidently elevated in 24 hour but returned to the normal level in 48-72 hours after burn, however it distinctly rose again after 72 hours post-burn. The results suggest that delayed fluid replacement induced generation of free radicals after burn injury, with the result of the occurrence of lipid peroxidation.

Animals↗
PubMed1993

Enhancement by non-mutagenic pesticides of GST-P positive hepatic foci development initiated with diethylnitrosamine in the rat.

The potential hepatocarcinogenicity of seven pesticides was examined using a rapid bioassay based on the induction of glutathione S-transferase placental form positive foci in the rat liver. Rats were initially injected with diethylnitrosamine and two weeks later were fed on diet supplemented with one of the pesticides for 6 weeks and then killed; all rats were subjected to a partial hepatectomy at week 3. Positive results were seen with chlorobenzilate (2000 ppm), vinclozolin (2000 ppm), malathion (4000 ppm), tecnazene (2000 ppm) and isoproturon (2000 ppm). S,S,S-tributylphosphorotrithioate (DEF, 200 ppm) and dicloran (2000 ppm) were negative in both number and area analyses. Although chlorobenzilate is carcinogenic in mice, malathion and vinclozolin have been reported as non-carcinogens in both rats and mice. Since the present system is based on the two-stage carcinogenesis hypothesis, it is possible that the chemicals showing positive results in this system possess at least tumor-promoting activity in the rat liver. This is very significant, as most carcinogens show tumor-promoting activity in their target organs.

Animals↗
PubMed1993

The early course of the Tourette's syndrome clinical spectrum.

We retrospectively studied 101 children with Tourette's syndrome to characterize the early course of illness and associated behavioral disturbances of attention deficit hyperactivity disorder (ADHD), obsessive-compulsive disorder (OCD), disruptive behavior (DB), and school problems (SP). For patients without ADHD (45%), OCD (50%), DB (67%), or SP (52%) at the time of initial evaluation, 13% developed ADHD, 8% OCD, 28% DB, and 25% SP during the observation period of 1.6 +/- 1.3 years (range, 0.5 to 7 years). For patients with behavioral disturbances initially, the problems were controlled or resolved for many over time and with therapy: ADHD, 46%; OCD, 47%; DB, 50%; and SP, 67%. Medication changes, assessed after a drug adjustment period between the initial and first follow-up visits (6 +/- 6 months), showed that drug dosages remained largely unchanged and few patients required the addition of new drugs: tic suppressants, 10%; anti-obsessional agents, 5%; and stimulants, 12%. Tic suppressants were withdrawn from 12%.

Adolescent↗
PubMed1993

[Localization and nucleotide sequence of propionyl acylase gene of Streptomyces mycarofaciens].

Our research showed that propionyl acylase gene is on 4.16kb insert DNA fragment originated from S. mycarofaciens in recombinant plasmid pIJM9. For localization of this gene on 4.16kb insert DNA fragment, sub-cloning has been carried out with religation of BamHI digested plasmid pIJM9. Among the transformants, molecular weight of recombinant plasmid pIJM95 harbouring in No. 5 transformant is 5.0kb. Molecular weight of insert DNA fragment is 0.53kb in this plasmid. In bioconversion experiment for spiramycin of No. 5 transformant, the bioconversion product was analysed with TLC, bioautography, HPLC and mass spectrum (FAB). Results showed that the bioconvert product is propionylspiramycin. No. 5 transformant is able to transform spiramycin into propionylspiramycin. Propionyl acylase gene was locolized on 0.53kb insert DNA fragment of recombinant plasmid pIJM95. Analysis result of DNA sequence showed that content of G + C is 68.2% for 0.53kb insert DNA fragment. More than 70 kinds of restriction endonuclease have cut sit on this fragment. From No.54-No.393 nucleotide, there is an open reading frame, which codes a polypeptide consisted of 122 amino acids. Start codon is ATG, stop codon is TGA.

Acyltransferases↗
PubMed1993

[Effect of tonifying kidney on compliability of the aged].

UNLABELLED: The clinical study of 80 aged individuals divided into treated group (Group I) and normal control (Group II) was carried out. According to the symptoms of Kidney Deficiency the aged was subdivided into Kidney Deficiency group (KDG) and non-Kidney Deficiency group. A semi-quantitative method and some indexes about compliability were used to evaluate the symptoms. RESULTS: After treatment the main symptoms of Kidney Deficiency such as lumbago, cold limbs, fatigue, cold aversion, feverish sensation in chest, palms and soles, etc. were significantly alleviated (P < 0.05) and the speed of reaction (SR) that reflects NS function in Group I and its KDG was also significantly improved. After exercise test, the ultrasono-cardiogram showed that in KDG of Group I, the ascending range of heart rate (HR) lessened during exercise and recovered more rapid than that before treatment. The difference was significant (P < 0.05). The HR was also significant different between the KDG groups of Group I and II during resting, exercise and recovering status (P < 0.05). Furthermore, after treatment the level of salival progesterone of the aged female was significantly. The determination of bone mineral content showed that in KDG after treatment, the density of ulnar line was remarkably elevated. These results showed that through tonifying Kidney and replenishing Qi could improve the functions of heart, brain, bone and endocrine systems of the aged persons, therefore improve their compliability.

Aged↗
PubMed1992

[Effect of prefrontal cortex on the neuronal activity of the nucleus raphe magnus in rats].

The unit discharge of neurons in nucleus raphe magnus (NRM) were recorded with glass microelectrodes in 33 waking and tubocurarine-immobilized rats. It is observed that effects of the noxious stimulation and prefrontal cortex (PFC) stimulation on spontaneous discharges of NRM neurons and effects of PFC stimulation on noxious-evoked discharges of NRM neurons by stimulating sural nerve. The results indicated that noxious stimulation and PFC stimulation could increase spontaneous discharge of most (68.18% and 60.82% respectively) NRM neurons. It was also noted that most (49/80) NRM neurons altered their spontaneous discharge in response to noxious stimulation and PFC stimulation in a similar manner. The remainder (31/80) opposite manners. PFC stimulation could alter the response of NRM neurons to noxious stimulation. PFC stimulation could enhance or reduce noxious-evoked discharge in NRM neurons which alter their spontaneous discharge in response to noxious stimulation and PFC stimulation in a similar manner. PFC stimulation could reduce noxious-evoked discharge in NRM neurons which alter their spontaneous discharge in opposite manners. The above results suggest that PFC and NRM have a functional relation. PFC could modulate nociceptive response and it might be partly responsible for influence on activity of neurons in NRM.

Animals↗
PubMed1992

[Magnetic stimulation motor evoked potential in multiple sclerosis. Comparison with visual evoked potentials, brain stem auditory evoked potentials and somatosensory evoked potentials].

This study consists of 45 patients with clinically definite MS, laboratory supported definite MS and clinically probable MS. We compared MEP results with other multimodal evoked potentials (VEP, BAEP and SEP). The abnormal rate of MEP was 87.6%, which was the highest. Abnormal MEP showed prolonged central motor conduction time (CMCT), consistent with pathological change of the demyelination. There was a evident correlation between the abnormal MEP and VEP, which is consistent with the most common MS (Devic Syndrome) in our country.

Adolescent↗
PubMed1992

Research on the main elements influencing blood pressure measurement by pulse wave velocity.

There have been considerable errors in non-invasive continuous beat-by-beat blood pressure (BP) measurement using the pulse wave velocity (PWV). To solve the problem, an in vivo study using 10 dogs was performed. The PWV-BP correlation under intact neuro-humoral factors was compared with that under the factors to be partly eliminated and the PWV-BP regularities were investigated using 10-beat average data. It was confirmed that the vasomotion and the viscoelasticity of vascular smooth muscles are the main elements influencing PWV-BP correlation through changing the elasticity of the arterial wall, and result in a 'shift' and 'zigzag swings' in the PWV-BP relationship so as to lower the PWV-BP correlation. By choosing large arteries and modifying the PWV algorithm, linear correlation coefficients of 0.97 +/- 0.027 and standard errors of the BP estimate of 5.29 +/- 2.84 mm Hg were obtained. The study suggests that the error could be further reduced by simultaneously measuring some related parameters.

Animals↗
PubMed1991

Hepatocarcinogenesis in transgenic mice carrying albumin-promoted SV40 T antigen gene.

We have developed transgenic mice that inherit albumin promoter-regulated simian virus 40 (SV40) large T antigen gene, expressed specifically in hepatocytes. These mice all develop multifocal hepatocellular carcinomas at around 5 months and die of liver insufficiency by 7 months. Sequential morphological observation of hepatocarcinogenesis revealed 5 distinct stages: (I) newborn to 2 weeks of age, neither recognizable histological changes nor cellular replication in spite of T antigen expression; (II) between 3 and 7 weeks, diffuse cytomegalic change of hepatocytes with numerous abnormal mitoses, usually resulting in cell death; (III) from 7 weeks onwards, quasi-regenerative small hepatocyte foci with a decreased tendency for cytomegaly in spite of T antigen expression, rapidly replacing the hepatic tissue; (IV) 11 weeks of age and thereafter, neoplastic foci and nodules with enzymatic alteration; (V) 20 weeks of age and thereafter, gross hepatocellular carcinomas with occasional pulmonary metastases. Considerable variation existed both in morphological and enzymatic features and T antigen expression among neoplastic lesions, including carcinomas. Thus, these transgenic mice clearly show a multistep process in hepatocarcinogenesis with remarkable synchrony and provide a promising model for analyzing the essential events of carcinogenesis at different stages.

Animals↗
PubMed1990

Long QT syndrome. New electrocardiographic characteristics.

The long QT syndrome is electrocardiographically characterized by a prolonged QT interval and by several other, more subtle, ST-T-U wave abnormalities, most of which have not been quantified. To determine the possible usefulness of several new electrocardiographic characteristics in identifying patients with known long QT syndrome, logistic regression models were applied to a data base of seven new, relatively independent, electrocardiographic repolarization variables. These were measured on digitized 12-lead electrocardiograms of 315 normal subjects and 37 patients with the long QT syndrome (members of well-identified long QT syndrome families, QTc greater than 0.44 second, 27% symptomatic), who ranged in age from 17 to 60 years. Electrocardiographic variables that independently differentiated (p less than 0.001) patients with long QT syndrome from normal subjects included quantitative measures of repolarization: early duration, rate, T wave symmetry, late phenomena, and heterogeneity. All selected repolarization variables except the early duration variable were essentially independent of the QTc (r2 less than 0.15), and all contributed significantly to the identification of patients with long QT syndrome. A classification model of five electrocardiographic predictor variables resulted in an estimated sensitivity (95% confidence interval) of 92.6% (81.6-100%) and an estimated specificity (95% confidence interval) of 95.8% (93.6-98.1%). This model performed significantly better than an alternative classification model that was based on the early duration variable as a single predictor variable. The symptomatic status of patients with long QT syndrome could not be predicted by any combination of the electrocardiographic variables in the investigated model.

Adolescent↗
PubMed1990

[Influence of zhuangling agent to metabolism of lipid in aged rats].

The influence of Zhuangling Agent to the metabolism of lipid in healthy old rats has been studied. The results indicate that the agent can decrease the level of serum total cholesterol, low-density lipoprotein low-density lipoprotein cholesterol and peroxilipid and meanwhile can increase serum superoxide-dismutase and enhance the activity of acid phosphatase in some parts of the tissues. The result suggests that Zhuangling Agent possibly has an effect of anti-arteriosclerosis.

Acid Phosphatase↗
PubMed1988

Structural characterization of the C4a anaphylatoxin from rat.

The C4a anaphylatoxin was purified from rat sera activated by heat-aggregated IgG. The anaphylatoxin was isolated by a three-step purification procedure and was judged to be homogeneous based on visualization of a single stained band after electrophoresis on both cellulose acetate membrane strips and on 9% SDS-polyacrylamide gels. Results from Ouchterlony and radioimmunoassay analysis indicated that neither rat C5A nor C3a contaminated the C4a preparation. Rat C4a is a glycoprotein estimated to be 11,000-12,000 mol. wt and contains 76 amino acid residues representing a mol. wt of 8577 and one oligosaccharide unit of 2000-3000 mol. wt. Rat C4a is weakly active in contracting guinea pig ileum at 0.1-1 microM, which is comparable with the activity of human C4a. Both human and bovine C4a are polypeptides free of carbohydrate while rat and presumably mouse C4a are glycoproteins. The complete primary structure of rat C4a anaphylatoxin has been elucidated as follows: (formula; see text)

Amino Acid Sequence↗
PubMedDate not supplied

Analysis of the human carcinoembryonic antigen promoter core region in colorectal carcinoma-selective cytosine deaminase gene therapy.

We isolated a 204-base pair carcinoembryonic antigen (CEA) promoter core region from a CEA-producing human colorectal carcinoma (CRC) and constructed retrovirus vectors carrying the expression cassette consisting of the CEA promoter core region and the cytosine deaminase (CD) gene. pCD2 retrovirus carrying the CD gene directed by the retrovirus long terminal repeat promoter served as a control vector. An in vitro study showed that the CEA promoter conferred CEA-producing cell-selective CD expression, specifically when the CD expression cassette was inserted into the 3' long terminal repeat of the retrovirus vector. CD-modified CRC xenografts in nude mice were sensitive to 5-fluorocytosine and caused a profound bystander effect on the unmodified CRC. When nude mice harboring intraperitoneally disseminated CRCs were injected intraperitoneally with the CD expression cassette-carrying retrovirus-producing cells, CD transduction into the disseminated CRCs and bone marrow (BM) was observed. CD expression was, however, restricted to CRCs, and it was observed in both CRCs and BM of mice injected with pCD2 retrovirus-producing cells, resulting in better therapeutic outcomes without BM suppression. These results indicate that effective and safe in vivo gene therapy for CRC may be feasible by transferring the CD gene controlled by the CEA promoter core region.

Animals↗