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Biomedical subjects

Y Yang

Publications and source records attributed to Y Yang.

At least 343 records · Page 19Linked to original sources
PubMed2001

[Effects of isocarbophos on the integrity of epidermic cell membrane of human skin].

OBJECTIVE: To investigate the effects of isocarbophos, a new and highly effective organophosphorus pesticide on the membranes of keratinocytes. METHODS: The epidermic cells of human skin cultured in the medium were adopted as a biological material. The activity of lactate dehydrogenase (LDH) was used as an indicator. We tested the activities of LDH and alkaline phosphatase (ALP) in the medium in different isocarbophos dosage conditions. RESULTS: It was found that the activity of LDH in the medium decreased with the increase of isocarbophos dosage. The LDH activities of the dosage groups were statistically different from those of the positive and negative groups. The ALP activities were of no significant difference between the groups. CONCLUSION: The above findings reveal that isocarbophos does not damage the membranes of keratinocytes directly, however it inhibits the LDH of human skin keratinocytes; thus it is suggested that isocarbophos like most organophosphorus pesticides used widely can pass through the intact human skin and poison the body before the skin is damaged. Therefore, protection during work hours is of paramount importance.

Alkaline Phosphatase↗
PubMed2001

[A comparative observation preoperatively and postoperatively of nasal mucosa in chronic sinusitis treated with endoscopic sinus surgery].

OBJECTIVES: To study morphologic and functional mucosal changes both preoperatively and postoperatively in chronic sinusitis (CS) treated with endoscopic sinus surgery (ESS). METHODS: 1. Saccharin test and light microscopic examination of nasal mucosa were taken preoperatively and postoperatively in 32 cases with CS and in 28 normal subjects as control. 2. Scanning and transmission electron microscopy were performed to exam preoperatively and postoperatively the nasal mucosa in 10 cases with CS and in 2 normal cases as control. RESULTS: 1. The preoperative saccharin test time (STT) in patients with CS was significantly longer than that in the controls (P < 0.001), and the postoperative STT became significantly shorter than that in preoperative one(P < 0.001). 2. The pathological changes of nasal mucosa, such as infiltration in inflammatory cells, edema, polypoid formations and pathologic glands were observed preoperatively. The infiltration in inflammatory cells, edema and polypoid formations were significantly released (P < 0.01) at four months after operation, and there was no significant difference comparing with the controls (P > 0.05). However, the pathologic glands were not reduced even after four months postoperatively. 3. The examination of electron microscopy demonstrated that the ultrastructure of nasal mucosa was impaired preoperatively and almost completely recovered at four months postoperatively. CONCLUSIONS: The normal structure and clearance function of nasal mucosa in patients with CS was impaired preoperatively, and the impaired structure and mucociliary clearing function of nasal mucosa were greatly improved after ESS and almost completely recovered at four months postoperatively. The pathologic glands and secretive function of nasal mucosa may need longer period for recovering.

Adolescent↗
PubMed2001

[Contralateral suppression of latency during distortion product otoacoustic emissions detection in guinea pigs].

OBJECTIVE: To investigate the cochlear micromechanics and the function of cochlear efferent system by detecting the distortion product otoacoustic emissions (DPOAE) with or without contralateral acoustic stimulation. METHODS: The DPOAE amplitude and latency of the cubic DPOAE (2f1-f2) were measured at f2 = 2, 4 and 6 kHz with or without 70 dB SPL broad-band noise contralateral stimulation in ears of 12 healthy pigmented guinea pigs, which were divided into two groups(A and B) and tested with different primary intensity level combinations. On the next day, an operation was made to open the acoustic bulla of right ear in Group A. Kainic Acid (KA, 1 microL of 60 mmol/L) was applied onto the round window membrane and wiped up carefully after three hours. The amplitude and latency of the cubic DPOAE from the left ear were measured after 6 hours of KA administration, with or without contralateral noise stimulation. RESULTS: Before the KA treatment, the amplitude of DPOAE induced by primaries of equal levels (L1 = L2) presented no significant change and the latency prolonged significantly during contralateral acoustic stimulation (Group A). But the amplitude at 2, 4 kHz of DPOAE induced by primaries of different levels (L1 > L2) decreased significantly and the latency also prolonged significantly (Group B). After KA administration in the contralateral ear of Group A, the contralateral acoustic stimulation had no significant effect on either amplitude or latency of DPOAE measured ipsilaterally. CONCLUSION: The result demonstrates that the latency is a sensitive index for the cochlear contralateral suppression. The efferent system may act as a negative feedback during the cochlear transduction.

Acoustic Stimulation↗
PubMed2001

[Relationship between three inner ear antigens and autoimmune inner ear disease].

OBJECTIVE: To investigate the relationship between three purified inner ear antigens and autoimmune inner ear disease (AIED), and to determine their expressions in normal guinea pig cochleas. METHODS: Guinea pigs were divided into group B, group C and group D and immunized respectively with three subcomponents of crude inner ear antigens (31,000, 42,000-45,000 and 60,000 proteins). Hearing thresholds, serum IgG levels and morphological changes of inner ear were observed. The protein expressions of these antigens were examined by immunohistochemistry. In the control group, antigens were replaced by gel homogenate of polyacrylamide. RESULTS: There were no significant differences of hearing threshold among groups before immunization with inner ear antigens (F = 0.07, P > 0.05). There were no significant changes of hearing thresholds and inner ear morphology in group C and control group. Hearing thresholds dropped in part of animals immunized with 31,000 or 60,000 protein. Hearing threshold of group B and D changed significantly after immunization, as compared with the control group(F = 9.12, P < 0.01). Serum IgG levels increased significantly in all experimental groups compared with the control group(F = 7.46, P < 0.01). The 31,000 protein distributed strictly in cochlear nerve, and 42,000-45,000 or 60,000 protein distributed widely, including the spiral ganglion, Corti's organ, stria vascularis and spiral ligament. CONCLUSIONS: Two subcomponents of 31,000 and 60,000 in crude inner ear antigen could induce autoimmune inner ear disease. The distribution of 31,000 protein was more tissue specific and might be used as a marker protein for clinical diagnosis of autoimmune inner ear disease.

Animals↗
PubMed2001

[Study of "living" radical polymerization by FTIR in situ].

Three types of living radical polymerization processes were monitored by means of FTIR spectrometer with handful diamond detector called as Dicomp in situ. It was found that both styrene and styrene/hydroxylpropyl methyacrylate (HPMA) could polymerize according to stable free radical polymerization (SFRP) mechanism in presence of 4-hydroxyl tetramethypiperidiyl-1-oxy(HTEMPO). For styrene/HPMA system, the styrene and HPMA conversion monitored by FTIR were linear with increase of molecular weight, but it gave longer induction period compared with that for St bulk polymerization. It was related to the hydrogen-transfer reaction between the propagating radicals with the end HPMA unit and HTEMPO. Furthermore, This following method in situ could be introduced into monitoring heterogeneous polymerization of styrene during atom transfer radical polymerization (ATRP). The apparent kinetics was found to be about zero order and not 1.0 order, due to propagating on the complex including radicals, CuX and bpy in heterogeneous interface. The polymerization rate will be not related to the St in bulk St phase.

Acrylamides↗
PubMed2001

[Application of digestion pot of HP hermetic seal in sample pretreatment in spectral analysis].

Atomic absorption spectrometry is a rapid and effective method for the quantitative determination of elements, but in complete dissolution of solid sample can greatly influence the analytical accuracy. The scale sample obtained from the power plant is hardly to digestion. In this paper, a method is proposed namely digestion pot of HP hermetic seal, it can digest the scale sample, and the digestion condition is obtained. After the sample is completely digested, the conventional elements in scale sample is determined by atomic absorption spectrometry.

Copper↗
PubMed2001

[Regulation on the immunological effect of mogrosides in mice].

OBJECTIVE: To investigate the cellular immunological effect of mogrosides in mice. METHODS: Mogrosides was administered to normal or CTX-induced immunosuppressive mice, and their macrophage function and T lymphocyte proliferation were detected. RESULTS: Mogrosides could promote phagocytosis and T lymphocyte proliferation significantly in the CTX-induced immunosuppressive mice, but not in the normal mice. CONCLUSION: The results suggested that mogrosides had certain up-regulation on cellular immunity in the CTX-induced immunosuppressive mice.

Animals↗
PubMed2001

[Comparative effects of carvedilol, losartan and their combination in preventing left ventricular remodeling after acute myocardial infarction in rats].

OBJECTIVE: To compare the effects of carvedilol, losartan and their combination in preventing from left ventricular remodeling (LVRM) after acute myocardial infarction(AMI) in rats. METHODS: Twenty-four hours after ligating left coronary artery, 100 surviving AMI female SD rats were randomly assigned to: (1) AMI control (n = 25), (2) carvedilol (1 mg x kg(-1) x d(-1)) (C1) (n = 25); (3) losartan (3 mg x kg(-1) x d(-1)) (L3)(n = 25); and (4) carvedilol (1 mg x kg(-1) x d(-1)) + losartan (3 mg x kg(-1) x d(-1)) (C1 + L3) (n = 25) groups. Sham-operated group (n = 17) were selected randomly as non-infarction control. After 4 weeks of therapy with the drugs by gastric gavage, hemodynamic studies were performed, then the rat hearts were fixed and pathologically analyzed. Exclusive of the rats with MI size < 35% or > 55%, complete data were obtained in 65 rats, which were comprised of AMI control (n = 13), C1 (n = 12), L3 (n = 13), C1 + L3 (n = 14) and sham-operated (n = 13) groups. RESULTS: There were no significant differences in MI size among the four AMI groups (45.8% - 46.7%, P > 0.05) . Compared with sham-operated group, Left ventricular (LV) end diastolic pressure (LVEDP), volume (LVV), weight (LVW), septal thickness (STh) and right ventricular weight (RVW) were all significantly increased (all P < 0.01 ) in AMI group, while the left ventricular pressure maximal rate of rise and fall (dp/dt) were significantly decreased (all P < 0.01). In comparison with AMI group, LVEDP, LVV, LVW, STh and RVW were all significantly decreased (all P < 0.01), while +/- dp/dt and +/- dp/dt/LVSP were significantly increased (P < 0.05 - 0.01) in all three therapy groups, with LVEDP decreasing more in the combination and L3 groups than in C1 group (P < 0.05 - 0.01) and STh decreasing more in the combination group than in C1 group (P < 0.01), but there were no significant differences in other variables among the three therapy groups. CONCLUSION: Carvedilol, losartan and their combination all can prevent from LVRM after AMI in rats, improve hemodynamics and LV function, with the combination superior.

Adrenergic beta-Antagonists↗
PubMed2001

[The clinical significance of detection of urinary ceruloplasmin in type 2 diabetes].

OBJECTIVE: To evaluate the clinical significance of detection of urinary ceruloplasmin (Cp) in type 2 diabetes. METHODS: To measure albumin/creatinine(Alb/Cr) and Cp/Cr in morning urinary specimens, from 134 normal controls and 3 960 diabetes, with RIA and ELISA separately. RESULTS: (1) The range of urinary Cp/Cr for normal controls was 0.01 - 1.12 ng/mmol, median 0.36 ng/mmol. Cp/Cr > 0.924 ng/mmol was considered as abnormal, and there was no significant difference between males and females, as well as among subjects of different age. (2) The sensitivity and specificity of Cp/Cr were 90% and 66% respectively with Alb/Cr > 2.5 mg/mmol as a golden standard for diabetic nephropathy, and Kappa value 0.48. Urinary Cp/Cr correlated well with Alb/Cr. (3)After sub-maximal exercise, Cp/Cr elevated markedly with no significant change of Alb/Cr. CONCLUSION: Urinary Cp/Cr could be considered as a marker of diabetic nephropathy and might be more sensitive than Alb/Cr.

Adult↗
PubMed2000

Knockout of the mouse glutamate cysteine ligase catalytic subunit (Gclc) gene: embryonic lethal when homozygous, and proposed model for moderate glutathione deficiency when heterozygous.

The biosynthesis of reduced glutathione (GSH) is carried out by the enzymes gamma-glutamylcysteine synthetase (GCL) and GSH synthetase. GCL is the rate-limiting step and represents a heterodimeric enzyme comprised of a catalytic subunit (GCLC) and a ("regulatory"), or modifier, subunit (GCLM). The nonhomologous Gclc and Gclm genes are located on mouse chromosomes 9 and 3, respectively. GCLC owns the catalytic activity, whereas GCLM enhances the enzyme activity by lowering the K(m) for glutamate and increasing the K(i) to GSH inhibition. Humans have been identified with one or two defective GCLC alleles and show low GSH levels. As an initial first step toward understanding the role of GSH in cellular redox homeostasis, we have targeted a disruption of the mouse Gclc gene. The Gclc(-/-) homozygous knockout animal dies before gestational day 13, whereas the Gclc(+/-) heterozygote is viable and fertile. The Gclc(+/-) mouse exhibits a gene-dose decrease in the GCLC protein and GCL activity, but only about a 20% diminution in GSH levels and a compensatory increase of approximately 30% in ascorbate-as compared with that in Gclc(+/+) wild-type littermates. These data show a reciprocal action between falling GSH concentrations and rising ascorbate levels. Therefore, the Gclc(+/-) mouse may be a useful genetic model for mild endogenous oxidative stress.

Alleles↗
PubMed2000

Ring opening of benzo[a]pyrene in the germ-free rat is a novel pathway for formation of potentially genotoxic metabolites.

The metabolism of benzo[a]pyrene (BP) is known to lead to a large number of oxygenated compounds, some of which can bind covalently to DNA. We have studied the integrated metabolism of BP in vivo in germ-free rats given (14)C-labeled BP. Urinary metabolites were separated into groups according to acidity using lipophilic ion exchangers. The groups were analyzed by mass spectrometry and were further fractionated by high-performance liquid chromatography. The fraction of urinary metabolites previously shown to contain N-acetylcysteine and glucuronic acid conjugates was found to contain derivatives of 7-oxo-benz[d]anthracene-3,4-dicarboxylic acid as major components. These compounds, which were identified by mass spectrometry and NMR, accounted for about 30% of the total metabolites in urine, demonstrating that, surprisingly, ring opening is a major pathway for metabolism of BP in the germ-free rat. The dicarboxylic acid may be excreted in urine as an ester glucuronide. By using the single cell gel electrophoresis or COMET assay, we were able to demonstrate that the anhydride of 7-oxo-benz[d]anthracene-3, 4-dicarboxylic acid was an efficient inducer of DNA damage. Taken together, these results indicate that the novel ring opening metabolic pathway may provide alternative mechanisms for the toxicity of BP.

Animals↗
PubMed2000

Inactivation of the human fragile histidine triad gene at 3p14.2 in monochromosomal human/mouse microcell hybrid-derived severe combined immunodeficient mouse tumors.

We have previously shown that inoculation of human chromosome 3 (chr3)/A9 mouse fibrosarcoma microcell hybrids (MCHs) into severe combined immunodeficient (SCID) mice was followed by the regular elimination of some 3p regions whereas a 3q region was retained even after prolonged mouse passage. Using this approach, referred to as the elimination test (Et), we have defined a common eliminated region (CER) of approximately 7 cM at 3p21.3 that was absent in all of the 27 tumors generated from five MCHs. Later, CER was reduced to a 1-Mb region, designated as CER1. Another eliminated region (ER2) at 3p21.1-p14.2 was absent in 21 of the 27 tumors. ER2 borders at but does not include the fragile histidine triad (FHIT) gene, considered as a putative tumor suppressor gene. In the present work, two new and two previously studied MCHs, and 13 derived SCID mouse tumors were analyzed by fluorescence in situ hybridization (FISH) chromosome painting and by PCR, using 72 chr3p-specific and 11 chr3q-specific markers. Nine tumors generated from three MCHs that carried cytogenetically normal chr3, remained PCR-positive for all of the chr3 markers tested. Designated as "PCR+" tumors, they were examined by reverse transcription (RT)-PCR, together with four of six previously studied tumors derived from MCH910.7, which carried a del(3)(pter-p21.1), for the expression of 14 human genes: 5 genes within CER1 (LIMD1, CCR1, CCR2, CCR3, CCR5), 5 genes located within regions that were homozygously deleted in a variety of carcinomas (ITGA4L, LUCA1, PTPRG, FHIT, DUTT1), and 4 other genes in chr3p (VHL, MLH1, TGM4, UBE1L). We found that VHL, MLH1, ITGA4L, LIMD1, UBE1L, LUCA1, PTPRG, and DUTT1 were expressed in the MCH lines in vitro and also in the derived SCID tumors. No transcripts that originated from the four CCR genes or from TGM4 could be detected in any of the MCH lines. Alone among the 14 genes examined, FHIT showed a tumor growth-associated change. It was expressed in vitro in five of seven MCH lines. Nine of 13 derived tumors had no FHIT transcript. The remaining 4 expressed a truncated mRNA and a reduced amount of the full-length mRNA. We have previously found that FHIT was deleted at the DNA level in 17 of 21 tumors derived from four MCHs. The remaining 4 of 21 had no FHIT transcript. Our compiled data show that FHIT was either physically or functionally impaired in all 34 of the 34 analyzed tumors. Variants with deleted or down-regulated FHIT have a selective growth advantage.

Acid Anhydride Hydrolases↗
PubMed2000

ZIC2 and Sp3 repress Sp1-induced activation of the human D1A dopamine receptor gene.

The human D(1A) dopamine receptor is transcribed from a tissue-specific regulated gene under the control of two promoters. An activator region (AR1) located between nucleotides -1154 and -1136 (relative to the first ATG) enhances transcription from the upstream promoter that is active in the brain. In this investigation, we sought to identify the nuclear factors that regulate the D(1A) gene through their binding to AR1 using yeast one-hybrid screening. Sp3 and Zic2 were among the positive clones isolated. Although Sp1 was not isolated from this screening and purified Sp1 alone does not bind to AR1 in gel shift experiments, this general transcription factor binds to AR1 in the presence of D(1A) expressing NS20Y nuclear extract and activates the D(1A) promoter. Thus, Sp1 appears to require an unknown factor(s) or post-translational modification to interact with AR1. On the other hand, Zic2 and Sp3 inhibit Sp1-induced activation of the D(1A) gene in an AR1-dependent manner. Zic2 and D(1A) genes have reciprocal brain regional distributions; Zic2 is expressed primarily in the cerebellum, and D(1A) is highly expressed in corpus striatum. These observations collectively suggest that one of the physiologic functions of Zic2 is repression of D(1A) gene transcription and that the intracellular balance among Sp1, Sp3 and Zic2 is important for regulating the tissue-specific expression of this dopamine receptor.

Base Sequence↗
PubMed2000

Preparation and preclinical evaluation of experimental group B streptococcus type III polysaccharide-cholera toxin B subunit conjugate vaccine for intranasal immunization.

Streptococcus group B (GBS) is usually carried asymptomatically in the vaginal tract of women and can be transferred to the newborn during parturition. Serum antibodies to the capsular polysaccharide (CPS) can prevent invasive diseases, whereas immunity acting at the mucosal surface may be more important to inhibit the mucosal colonization of GBS and thus the risk of infection for the newborn. We prepared different GBS type III CPS-protein conjugate vaccines and evaluated their systemic and mucosal immunogenicity in mice. GBS type III CPS was conjugated to tetanus toxoid (TT) or recombinant cholera toxin B subunit (rCTB) either directly or to rCTB indirectly via TT. The conjugation was performed by different methods: (1) CPS was coupled to TT with 1-ethyl-3 (3-dimethylaminopropyl)-carbodiimide (EDAC), using adipic acid dihydrazide (ADH) as a spacer; (2) CPS was conjugated with rCTB using reductive amination; or, (3) N-succinimidyl 3-(2-pyridyldithio) propionate (SPDP) was used to bind rCTB to the TT of the CPS-TT conjugate. Mice were immunized with these conjugates or purified CPS by subcutaneous (s.c.) and intranasal (i. n.) routes. Antibodies to GBS III in serum, lungs and vagina were measured with ELISA. All of the CPS-protein conjugates were superior to unconjugated CPS in eliciting CPS-specific immune responses in serum and mucosal tissue extracts. The conjugates, when administrated s.c., induced only IgG responses in serum, lung and vagina, while i.n. vaccination also elicited IgA responses in the lungs and vagina. The CPS-TT conjugate administrated i.n. induced a strong serum IgG, but only a weak mucosal IgA response, while the CPS-rCTB conjugate elicited high IgG as well as IgA antibodies in the lungs after i.n. immunization. GBS III CPS-TT conjugated with rCTB produced a strong systemic and local anti-CPSIII response after i.n. administration. Co-administration of CT as adjuvant enhanced the anti-CPS systemic and mucosal immune responses further after i.n. administration with the CPS conjugates. These findings indicate that: (i) i.n. immunization with GBS CPS-protein conjugates was more effective than s.c immunization for stimulating serum as well as mucosal immune responses; (ii) rCTB as a carrier protein for GBS III CPS could markedly improve the mucosal immune response; and (iii) the experimental GBS type III CPS conjugates containing rCTB should be investigated as mucosal vaccine to prevent GBS infection in humans.

Administration, Intranasal↗
PubMed2000

Protective effects of prenatal choline supplementation on seizure-induced memory impairment.

Choline is an essential nutrient for rats and humans, and its availability during fetal development has long-lasting cognitive effects (Blusztajn, 1998). We investigated the effects of prenatal choline supplementation on memory deficits associated with status epilepticus. Pregnant rats received a control or choline-supplemented diet during days 11-17 of gestation. Male offspring [postnatal day 29 (P29)-32] were tested for their ability to find a platform in a water maze before and after administration of a convulsant dose of pilocarpine at P34. There were no differences between groups in water maze performance before the seizure. One week after status epilepticus (P41-P44), animals that had received the control diet prenatally had a drastically impaired performance in the water maze during the 4 d testing period, whereas prenatally choline-supplemented rats showed no impairment. Neither the seizures nor the prenatal availability of choline had any effect on hippocampal choline acetyltransferase or acetylcholinesterase activities. This study demonstrates that prenatal choline supplementation can protect rats against memory deficits induced by status epilepticus.

Acetylcholinesterase↗
PubMed2000

Solution structure of the focal adhesion adaptor PINCH LIM1 domain and characterization of its interaction with the integrin-linked kinase ankyrin repeat domain.

PINCH is a recently identified adaptor protein that comprises an array of five LIM domains. PINCH functions through LIM-mediated protein-protein interactions that are involved in cell adhesion, growth, and differentiation. The LIM1 domain of PINCH interacts with integrin-linked kinase (ILK), thereby mediating focal adhesions via a specific integrin/ILK signaling pathway. We have solved the NMR structure of the PINCH LIM1 domain and characterized its binding to ILK. LIM1 contains two contiguous zinc fingers of the CCHC and CCCH types and adopts a global fold similar to that of functionally distinct LIM domains from cysteine-rich protein and cysteine-rich intestinal protein families with CCHC and CCCC zinc finger types. Gel-filtration and NMR experiments demonstrated a 1:1 complex between PINCH LIM1 and the ankyrin repeat domain of ILK. A chemical shift mapping experiment identified regions in PINCH LIM1 that are important for interaction with ILK. Comparison of surface features between PINCH LIM1 and other functionally different LIM domains indicated that the LIM motif might have a highly variable mode in recognizing various target proteins.

Amino Acid Sequence↗
PubMed2000

Novel mutations in spastin gene and absence of correlation with age at onset of symptoms.

Autosomal dominant hereditary spastic paraplegia is genetically heterogeneous, with at least five loci identified by linkage analysis. Recently, mutations in spastin were identified in SPG4, the most common locus for dominant hereditary spastic paraplegia that was previously mapped to chromosome 2p22. We identified five novel mutations in the spastin gene in five families with SPG4 mutations from North America and Tunisia and showed the absence of correlation between the predicted mutant spastin protein and age at onset of symptoms.

Adenosine Triphosphatases↗