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Biomedical subjects

Y Lü

Publications and source records attributed to Y Lü.

At least 19 recordsLinked to original sources

[Current evolution of plasma sprayed hydroxyapatite coating].

The present attempt is to briefly review the processing and properties of plasma sprayed hydroxyapatite coatings in terms of characteristics of hydroxyapatite ceramics, plasma spraying technology, titanium-ceramic interfacial cracking and component designing of hydroxyapatite coating based composite. The coating is a weak part in implant system. The main purpose of research on plasma spraying technology and component designing is to improve coating integrality and coating-matrix adhesion strength. Functionally gradient materials can provide a new route to solve the above two problems.

Biomechanical Phenomena↗

[Isolation of genes associated with renoprotective effects of astragalus and angelica by silver staining mRNA differential display].

OBJECTIVE: To isolate genes associated with chronic progression of renal diseases and renoprotective effects of Astragalus and Angelica(A & A). METHODS: Chronic puromycin nephropathy, which is characterized by massive proteinuria and progressive glomerular sclerosis and tubulointerstitial fibrosis, was induced in SD rats by repeated peritoneal injections of puromycin. Rats were randomly divided into three groups: (1) normal control (n = 7), (2) puromycin nephropathy without A&A treatment (n = 7), (3) puromycin nephropathy A & A treatment (3 ml/d, n = 7). After 12 weeks, serum, urine and renal tissue were collected for study. The technique of silver staining mRNA differential display (DD) was used to investigate the changes of gene expression in kidneys of normal and nephropathy with and without A&A treatment rats. Genes expressing differently during the progression of renal diseases were isolated and the progression could be normalized by A&A. RESULTS: Twenty-six candidate cDNA fragments were isolated with DD. Northern blot analysis of eight randomly chosen candidate cDNA fragments demonstrated one exhibiting reduced mRNA expression in the fibrogenic process but upregulated by A&A treatment. Besides kidney, the gene was also expressed in lung, heart, liver and spleen. Whether it takes part in fibrogenic processes of these organs needs further study. Homology analysis through BLAST revealed that this gene was a novel one. CONCLUSION: Silver staining mRNA differential display is a simple and quick technique for isolating differently expressed genes. The downregulated expression of the isolated new gene may contribute significantly to the fibrogenic process and be associated with A&A's protective effects.

Angelica sinensis↗

The distribution of substance P receptor (NK1)-like immunoreactive neurons in the newborn and adult human spinal cord.

Substance P receptor (i.e. NK1)-like immunoreactive (SPR-LI) neurons were observed in the newborn and adult human spinal cord. Substance P receptor-like immunoreactive neuronal cell bodies were seen most frequently in lamina I, and were scattered throughout the remaining laminae of the dorsal horn and the area around the central canal. Some neurons in the intermediolateral nucleus also showed weak immunoreactivity. The pattern of distribution of SPR-LI neurons in the adult spinal cord was essentially the same as that in the newborn spinal cord. However, SPR-LI neurons cell bodies were seen much more frequently in the newborn than in the adult dorsal horn, especially in lamina II.

Adult↗

Effects of acupuncture on the pituitary-thyroid axis in rabbits with fracture.

PURPOSE: To observe the effects of acupuncture on the pituitary-thyroid axis in rabbits with fracture. METHOD: 36 male rabbits with a 3-mm width experimental defect in the middle segment of the left radius were randomly divided into the treatment group and control group, and the changes in serum T3, T4 and TSH contents in different weeks were investigated. RESULTS: Serum T3, T4 and TSH contents in the treatment group all were higher than those in the control group, with statistically significant differences in the contents of T4 and TSH in the second week and T3 content in the fourth week (P < 0.01 or P < 0.05). CONCLUSION: The action of promoting union of fracture is possibly related with the pituitary-thyroid axis.

Animals↗

[A surveillance study on penicillin-resistant Streptococcus pneumoniae in China].

OBJECTIVES: To find out if there are penicillin-resistant Streptococcus pneumoniae and the resistance rate in China. METHODS: 989 pediatric patients with respiratory tract infections aged from 6 months to 3 years from two pediatric units were enrolled. Perthroat swabs were immediately streaked onto blood agar plates and incubated overnight. Pneumococci were identified and isolated. Antibiotic susceptibility was assessed by the disk diffusion method and MIC determination according to Protocol and NCCLS. RESULTS: Of the 51 Streptococcus pneumoniae isolates, 5 strains had zones > or = 20 mm. Two of the 5 strains had penicillin MICs > or = 0.1 mg/L (2 and 4 mg/L) and considered to be fully resistant to penicillin(4%). The resistance rate to ceftriaxone and cefotaxime was 0 and 4% respectively. For the other 10 antimicrobial agents, the resistance rates were as follows: ampicillin 12%, piperacillin 26%, furbenicillin 14%, cefuroxime 6%, erythromycin 54%, clarithromycin 52%, meleumycin 64%, roxithromycin 52%, chloramphenicol 32%, and tetracycline 100%. CONCLUSIONS: The study suggested that penicillin resistant Streptococcus Pneumoniae strains also exist, and the cross-resistance is a significant phenomenon in China.

Ampicillin Resistance↗

Study on delay two-phase multiple organ dysfunction syndrome.

OBJECTIVE: To study the injury factors, pathogenic process and clinical features of delay two-phase multiple organ dysfunction syndrome (MODS) in severe burned patients and to replicate a standardized animal model that would accurately imitate the clinical features of MODS. METHODS: Forty-five human patients with burn size larger than 30% total body surface area (TBSA) were analyzed. All of them underwent severe burn shock in early stage and sepsis in late stage. Thirty-two goats were randomly divided into three groups: 1) hemorrhagic shock (group H, n = 6); 2) endotoxemia (group E, n = 6); and 3) hemorrhagic shock plus endotoxemia (group M, n = 20). Hemorrhagic shock was produced according to the method of Wigger (6.7 kPa for an hour, 1 kPa = 7.5 mmHg). Endotoxin (E. coli O111 B4) was given via the portal vein 24 hours after the resuscitation of hemorrhagic shock, in a dose of 30 ng/kg/min for 5 consecutive days. During the observation period of 10 days, all animals were hemodynamically monitored, given standard metabolic support and due cardiac and pulmonary support according to human intensive care. RESULTS: All the patients showed burn shock at 1-3 days and hyperdynamic circulation, hypermetabolism and systemic inflammatory responses over two weeks post-injury. Thirteen cases were found to develop MODS according to the prevailing diagnostic criteria, and 10 of them died with a mortality of 77%. Eighteen animals died in group M with a mortality of 90%, 12 of the 18 developed MODS, with overall incidence of 60%. Most animals in group M showed changes similar to that observed in human cases. The experimentation proved that in the pathogenic process of MODS, there was a two-hit phenomenon in the dvelopment of the syndrome. To prevent the development of MODS, it therefore was imperative to blunt the first hit or the second hit, so that an excessive inflammatory response was alleviated. This postulation has been verified in the treatment of extensive burns. Two patients with burn extent reaching 100% TBSA survived with only mild acute respiratory distress syndrome (ARDS) and renal dysfunction after comprehensive treatment of burn shock, including adequate fluid resuscitation, drugs to remove oxygen free radicals, rapid restoration of pHi, and early extensive excision of burn eschars. CONCLUSION: Both in human patients or animal experimentation, the typical delay two-phase MODS is shown to be produced by two successive insults in the forms of hypovolemic shock and sepsis. This postulation is helpful in formulating the prevention and treatment modality of MODS.

Adult↗

[Expression of p53 and ras p21 gene products in malignant transformed V79 cell induced by various organic components of DEPs].

The effect of various fractions of diesel exhausted particles on the expression of mutant p53 antigen product and ras oncogene p21 product was examined by immunohistochemical method in malignant transformed V79 cell. The result showed that all fractions of diesel exhausted particles (DEPs) could significantly increase the expression of p53 products (P < 0.01). It demonstrated that the organic fractions of DEPs could induce the mutation of p53 suppressor gene in malignant transformed cells. But the expression levels of ras oncogene p21 product were not changed under the same experimental conditions (P > 0.05).

Animals↗

[High frequency mutation of p53 gene in human gastric cancer and precancerous lesions].

OBJECTIVE: To determine the frequency and type of p53 gene mutation with the progression of human gastric carcinogenesis. METHODS: Single strand conformation polymorphism (SSCP) and DNA sequencing were performed on 56 biopsied tissues, including gastric cancer (n = 23), dysplasia (Dys, n = 16) and intestinal metaplasia (IM, n = 17). RESULTS: p53 gene mutation was detected in 60.1% of cancer, 31.3% of Dys and 11.8% of IM. Mutations covered exon 5-8 without hot spot. GC-->AT transitions (30.4%) and GC-->TA transversions (26.1%) were the major patterns of p53 mutation. Missense (73.9%) and frame shift mutations covered 86.9% of all mutations. CONCLUSION: In the process of human gastric carcinogenesis, multiple factors are involved in p53 gene mutations. The mutation rate increases with the progression of malignant changes in the gastric mucosa. Missense and frame shift mutations are possibly the major cause of p53 inactivation.

Adenocarcinoma↗

[Numerical change of 7, 17 and Y chromosomes in human lung carcinoma detected by fluorescence in situ hybridization].

OBJECTIVE: To study the copy number of chromsomes 7,17 and Y in lung carcinomas. METHODS: Fluorescence in situ hybridization (FISH) was used to detect the number of above mentioned chromosomes on the touch smears of 17 cases of lung carcinoma (adenocarcinoma and squamous cell carcinoma). RESULTS: Triploid chromosome 7 FISH signals were found in 31.73% of the tumor nuclei, dipoid chromosome 17 FISH signals in 43.00% and monoploid chromosome Y FISH signals in 58.04% of these nuclei. CONCLUSIONS: The number of chromosome 7 was obviously increased in both lung adenocarcinoma and squamous cell carcinoma, and the rate of trisomy 7 was the highest. In addition, there is a significant difference in the distribution of chromosome 7 ploidy between lung adenocarcinoma and squamous cell carcinoma.

Adenocarcinoma↗

[Chromosome marker--2q- during carcinogenesis and development of human lung cancer].

OBJECTIVE: To study the cytogengtic alterations during the development of human lung cancer and to clarify the genetic basis of lung cancer. METHODS: Using Fluorescence in situ Hybridization FISH, we have studied the chromosomal alterations of chromosome 2 and 3 in human bronchial epithelial cell line M, and 12 primary non-small cell lung cancer (NSCLC) specimens. RESULTS: 2q- was found in the later passage of human bronchial epithelial cell line M, and 3 out of 7 primary NSCLC specimens tested. 3p- being noted in five cases of 12 primary NSCLC patients examined was the first cytogenetic discovery and the most prominent abnormality in lung cancer. 2q- was rarely reported in human lung cancer before. But loss of heterozygosity by RFLP analysis for 2q had been reported in lung cancer. CONCLUSION: 2q- is also a common chromosome abnormality in human lung cancer. There would also be one or more putative tumor suppressor gene(s) on the long arm of chromosome 2. Loss of the gene(s) may contribute to the carcinogenesis of human non-small-cell lung cancer.

Adenocarcinoma↗

Coexistence of mu-opioid receptor-like and substance P-like immunoreactivities in the cat dorsal root ganglionic neurons.

Coexistence of mu-opioid receptor (MOR)-like immunoreactivity (LI) and substance P (SP)-LI in the neurons of the cat dorsal root ganglia (DRG) was examined by a double immunofluorescence histochemical method. Approximately 91% of SP-LI neurons in the DRG showed MOR-LI. However, SP-LI was exhibited in approximately 28% of the neurons labeled with MOR-LI. These morphological findings indicated that the MOR exist on most of the primary afferent SP-containing terminals, and suggest that MOR may regulate SP release from the primary afferent terminals in the cat dorsal horn.

Afferent Pathways↗

Synthesis and structure-activity relationships of 1,2,3,4-tetrahydroquinoline-2,3,4-trione 3-oximes: novel and highly potent antagonists for NMDA receptor glycine site.

A series of 1,2,3,4-tetrahydroquinoline-2,3,4-trione 3-oximes (QTOs) was synthesized and evaluated for antagonism of NMDA receptor glycine site. Glycine site affinity was determined using a [3H]DCKA binding assay in rat brain membranes and electrophysiologically in Xenopus oocytes expressing 1a/2C subunits of cloned rat NMDA receptors. Selected compounds were also assayed for antagonism of AMPA receptors in Xenopus oocytes expressing rat brain poly-(A)+RNA. QTOs were prepared by nitrosation of 2,4-quinolinediols. Structure-activity studies indicated that substitutions in the 5-, 6-, and 7-positions increase potency, whereas substitution in the 8-position causes a decrease in potency. Among the derivatives evaluated, 5,6,7-trichloro-QTO was the most potent antagonist with an IC50 of 7 nM in the [3H]DCKA binding assay and a Kb of 1-2 nM for NMDA receptors expressed in Xenopus oocytes. 5,6,7-Trichloro-QTO also had a Kb of 180 nM for AMPA receptors in electrophysiological assays. The SAR of QTOs was compared with the SAR of 1,4-dihydroquinoxaline-2,3-diones (QXs). For compounds with the same benzene ring substitution pattern, QTOs were generally 5-10 times more potent than the corresponding QXs. QTOs represent a new class of inhibitors of the NMDA receptor which, when appropriately substituted, are among the most potent glycine site antagonists known.

Animals↗

[The overexpression of c-met oncogene correlation with gastric mucosal lesion].

OBJECTIVE: To determine whether there is a relationship between overexpression of c-met oncoprotein and stage of human gastric mucosal lesions, and its significance. METHOD: Immunohistochemical staining was used in 157 cases of endoscopic biopsies with c-met monoclonal antibody, S-19, which was raised against the human c-met gene product. RESULTS: overexpresion of c-met oncoprotein was detected in 3/30 cases (10%) of superficial gastritis, 4/33 cases (12.1%) of chronic atrophic gastritis, 10/31 cases (32.3%) of intestinal mataplasia, 10/30 cases (33.3%) of dysplasia, and 10/30 cases (33.3%) of gastric carcinoma. The positive staining rate was higher in intestinal mataplasia (54.8%), dysplasia (56.7%), carcinoma (53.3%) than in two kinds of simple chronic gastritis (P < 0.05). The positive staining was obviously located in luminal membrane of mucosal cells. The positive cells were mainly situated in proliferative cell zone of gastric glands. Moreover, the weak staining only in this zone was shown in two of the three normal mucosa. CONCLUSIONS: The overexpression of c-met may be involved in proliferation of gastric mucosa. It is possible that persistent overexpression of c-met oncoprotein is associated with the malignant transformation of gastric mucosal cells.

Adenocarcinoma↗

[A study of 5-fluorouracil on bovine trabecular meshwork cells in vitro].

OBJECTIVE: To determine whether the clinical use of 5-fluorouracil (5-FU) may have any toxic effects on trabecular meshwork cells. METHODS: Bovine trabecular meshwork (BTM) cells were cultured in vitro. The effects of 5-FU on BTM cells concerning cellular morphology, ultrastructure, vitality and phagocytosis were observed. RESULT: The safe dosage of 5-FU on BTM cell was 1 x 10-6g.ml-1. CONCLUSION: Based on the pharmacokinetic data in the rabbit anterior chamber, it is suggested that the 5-FU dosage of conventional use cause no injury to human trabecular meshwork cells.

Animals↗

Synthesis and structure-activity relationships of substituted 1,4-dihydroquinoxaline-2,3-diones: antagonists of N-methyl-D-aspartate (NMDA) receptor glycine sites and non-NMDA glutamate receptors.

A series of mono-, di-, tri-, and tetrasubstituted 1,4-dihydroquinoxaline-2,3-diones (QXs) were synthesized and evaluated as antagonists at N-methyl-D-aspartate (NMDA)/glycine sites and alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid-preferring non-NMDA receptors. Antagonist potencies were measured by electrical assays in Xenopus oocytes expressing rat whole brain poly(A)+ RNA. Trisubstituted QXs 17a (ACEA 1021), 17b (ACEA 1031), 24a, and 27, containing a nitro group in the 5 position and halogen in the 6 and 7 positions, displayed high potency (Kb approximately 6-8 nM) at the glycine site, moderate potency at non-NMDA receptors (Kb = 0.9-1.5 microM), and the highest (120-250-fold) selectivity in favor of glycine site antagonism over non-NMDA receptors. Tetrasubstituted QXs 17d,e were more than 100-fold weaker glycine site antagonists than the corresponding trisubstituted QXs with F being better tolerated than Cl as a substituent at the 8 position. Di- and monosubstituted QXs showed progressively weaker antagonism compared to trisubstituted analogues. For example, removal of the 5-nitro group of 17a results in a approximately 100-fold decrease in potency (10a,b,z), while removal of both halogens from 17a results in a approximately 3000-fold decrease in potency (10v). In terms of steady-state inhibition, most QX substitution patterns favor antagonism at NMDA/glycine sites over antagonism at non-NMDA receptors. Among the QXs tested, only 17i was slightly selective for non-NMDA receptors.

Animals↗

Expression of c-fos protein in substance P receptor-like immunoreactive neurons in response to noxious stimuli on the urinary bladder: an observation in the lumbosacral cord segments of the rat.

Chemical irritation of the urinary bladder with formalin in the rat induced c-fos protein-like immunoreactivity in more than 80% of substance P receptor-like immunoreactive (SPR-LI) neurons of the dorsal commissural nucleus, sacral parasympathetic nucleus and lamina I in the 6th lumbar and 1st sacral cord segments. These neurons with SPR-LI may receive noxious information from the urinary bladder through the primary afferent fibers with substance P.

Animals↗

[Detecting human papillomavirus DNA of condylomata and pseudo-condylomata by in situ hybridization and polymerase chain reaction in paraffin-embedded specimens].

One hundred and thirty seven cases of paraffin-embedded tissue specimens biopsied each from condylomata and pseudo-condylomata of vulva and vagina were examined. Type 6b 11 human papillomavirus (HPV) DNA was detected in condylomata by in situ hybridization using digoxigeninlabelled probes and polymerase chain reaction (PCR). The positive rate was 82.5%, 83.9% respectively. It was negative in the 137 cases of pseudo-condylomata by in situ hybridization, but positive in 3 cases by PCR. For a correct diagnosis, the necessity of combining the data of clinical finding, microscopic examination and in situ hybridization or PCR is emphasized. Our results showed that pseudo-condylomata represent dysplastic appearances of vulval and vaginal mucosa, which become more marked during pregnancy and fungal or trichomonal infections, and could rather easily be misdiagnosed as condylomata.

Condylomata Acuminata↗