Biomedical subjects

Y Lin

Publications and source records attributed to Y Lin.

At least 343 records · Page 19Linked to original sources

PubMed1998

A common position-dependent mechanism controls cell-type patterning and GLABRA2 regulation in the root and hypocotyl epidermis of Arabidopsis.

A position-dependent pattern of epidermal cell types is produced during root development in Arabidopsis thaliana. This pattern is reflected in the expression pattern of GLABRA2 (GL2), a homeobox gene that regulates cell differentiation in the root epidermis. GL2 promoter::GUS fusions were used to show that the TTG gene, a regulator of root epidermis development, is necessary for maximal GL2 activity but is not required for the pattern of GL2 expression. Furthermore, GL2-promoter activity is influenced by expression of the myc-like maize R gene (35S::R) in Arabidopsis but is not affected by gl2 mutations. A position-dependent pattern of cell differentiation and GL2-promoter activity was also discovered in the hypocotyl epidermis that was analogous to the pattern in the root. Non-GL2-expressing cell files in the hypocotyl epidermis located outside anticlinal cortical cell walls exhibit reduced cell length and form stomata. Like the root, the hypocotyl GL2 activity was shown to be influenced by ttg and 35S::R but not by gl2. The parallel pattern of cell differentiation in the root and hypocotyl indicates that TTG and GL2 participate in a common position-dependent mechanism to control cell-type patterning throughout the apical-basal axis of the Arabidopsis seedling.

Arabidopsis↗

PubMed1998

Growth of virulent and avirulent Mycobacterium tuberculosis strains in human macrophages.

Mycobacterium tuberculosis H37Rv causes progressive disease in animals, whereas the H37Ra strain does not. The relevance of this difference in virulence to human infection is uncertain because these strains have been shown to have similar growth rates in human macrophages. To evaluate the intracellular growth of M. tuberculosis strains in macrophages under conditions similar to those encountered in vivo, we infected human monocyte-derived macrophages with H37Ra, H37Rv, or one of four isolates from tuberculosis patients at a low bacillus-to-macrophage ratio. H37Rv and the patient isolates grew significantly faster than H37Ra, based on the numbers of CFU and acid-fast bacilli. These findings did not result from extracellular mycobacterial growth, differential macrophage viability, or bacillary clumping. In contrast to other published results, these findings indicate that the virulence characteristics of M. tuberculosis strains in animal models are relevant to human tuberculosis infection.

Cytokines↗

PubMed1998

Chemokine production by a human alveolar epithelial cell line in response to Mycobacterium tuberculosis.

To investigate the role of chemokines during the initial local response to Mycobacterium tuberculosis in the human lung, we studied chemokine production by the human alveolar epithelial cell line A549 after infection with M. tuberculosis. M. tuberculosis-infected A549 cells produced mRNAs and protein for monocyte chemotactic protein-1 (MCP-1) and interleukin-8 (IL-8) but not mRNAs for macrophage inflammatory protein 1alpha (MIP-1alpha), MIP-1beta, and RANTES. Chemokine production in response to M. tuberculosis was not dependent on production of tumor necrosis factor alpha, IL-1beta, or IL-6. Two virulent clinical M. tuberculosis isolates, the virulent laboratory strain H37Rv, and the avirulent strain H37Ra elicited production of comparable concentrations of MCP-1 and IL-8, whereas killed M. tuberculosis and three Mycobacterium avium strains did not. The three virulent M. tuberculosis strains grew more rapidly than the avirulent M. tuberculosis strain in the alveolar epithelial cell line, and the three M. avium strains did not grow intracellularly. These findings suggest that intracellular growth is necessary for mycobacteria to elicit production of MCP-1 and IL-8 by alveolar epithelial cells but that virulence and the rate of intracellular growth do not correlate with chemokine production. Alveolar epithelial cells may contribute to the local inflammatory response in human tuberculosis by producing chemokines which attract monocytes, lymphocytes, and polymorphonuclear cells.

Cell Line↗

PubMed1998

Production of monocyte chemoattractant protein 1 in tuberculosis patients.

To investigate the role of monocyte chemoattractant protein 1 (MCP-1) in the immune response to Mycobacterium tuberculosis, we studied MCP-1 production in tuberculosis patients. CD14+ blood monocytes from tuberculosis patients spontaneously expressed higher levels of MCP-1 mRNA and protein than CD14+ monocytes from healthy tuberculin reactors. MCP-1 production in lymph nodes from tuberculosis patients was also markedly increased. These findings suggest that MCP-1 can contribute to the antimycobacterial inflammatory response by attracting monocytes and T lymphocytes.

Chemokine CCL2↗

PubMed1998

RMP, a novel RNA polymerase II subunit 5-interacting protein, counteracts transactivation by hepatitis B virus X protein.

To modulate transcription, regulatory factors communicate with basal transcription factors and/or RNA polymerases in a variety of ways. Previously, it has been reported that RNA polymerase II subunit 5 (RPB5) is one of the targets of hepatitis B virus X protein (HBx) and that both HBx and RPB5 specifically interact with general transcription factor IIB (TFIIB), implying that RPB5 is one of the communicating subunits of RNA polymerase II involved in transcriptional regulation. In this context, we screened for a host protein(s) that interacts with RPB5. By far-Western blot screening, we cloned a novel gene encoding a 508-amino-acid-residue RPB5-binding protein from a HepG2 cDNA library and designated it RPB5-mediating protein (RMP). Expression of RMP mRNA was detected ubiquitously in various tissues. Bacterially expressed recombinant RMP strongly bound RPB5 but neither HBx nor TATA-binding protein in vitro. Endogenous RMP was immunologically detected interacting with assembled RPB5 in RNA polymerase in mammalian cells. The central part of RMP is responsible for RPB5 binding, and the RMP-binding region covers both the TFIIB- and HBx-binding sites of RPB5. Overexpression of RMP, but not mutant RMP lacking the RPB5-binding region, inhibited HBx transactivation of reporters with different HBx-responsive cis elements in transiently transfected cells. The repression by RMP was counteracted by HBx in a dose-dependent manner. Furthermore, RMP has an inhibitory effect on transcriptional activation by VP16 in the absence of HBx. These results suggest that RMP negatively modulates RNA polymerase II function by binding to RPB5 and that HBx counteracts the negative role of RMP on transcription indirectly by interacting with RPB5.

Amino Acid Sequence↗

PubMed1998

Three noncontiguous peptides comprise binding sites on high-molecular-weight kininogen to neutrophils.

The binding of high-molecular-weight kininogen (HK) to neutrophils (polymorphonuclear leukocytes, PMN) is required for the stimulation of aggregation and degranulation by human plasma kallikrein as well as the displacement of fibrinogen from this cell surface. The putative receptor for HK is the leukocyte integrin alphaMbeta2, and domains 3 (D3) and 5 (D5) of HK form its binding site. To further map the binding sites on HK for PMN, we used D3 recombinant exon products and designed peptides from D3 and D5. In D3, a heptapeptide, Leu271-Ala277, from exon 7 product, and a peptide, Cys333-Cys352, from exon 9 product can inhibit binding of kininogen to PMN. Two contiguous peptides from D5 in the histidine-glycine-rich region, Gly442-Lys458 and Phe459-Lys478, each inhibit the binding of HK to PMN. This study has thus delineated three noncontiguous surface-oriented sequences on HK, which together comprise all or most of the binding site for human PMN.

Amino Acid Sequence↗

PubMed1998

Estimated number of patients with chronic renal failure but not with end-stage renal disease in Japan: comparisons between two estimation methods.

We estimated the number of patients with chronic renal failure (CRF) but not with end-stage renal disease (ESRD) in Japan by two methods: a nationwide survey and an estimation using incidence rates of ESRD among CRF patients as well as the number of incident ESRD. The former estimated the number of patients with CRF but not with ESRD as 154,000 (95% confidence interval 139,000-168,000), while so did the latter as 142,000 (133,000-150,000). It follows that the number of CRF patients including ESRD could amount to more than 300,000, which would give a substantial impact on public health in Japan. Despite some own methodological issues in estimation, the two estimates were reasonably in good agreement: supporting their methodological validity in estimation, since sources of errors appeared to be quite independent of each other.

Adult↗

PubMed1998

Descriptive epidemiology of pancreatic cancer in Japan.

This paper aimed to explore descriptive epidemiological features of pancreatic cancer in Japan, by examining secular trends in mortality (1950-1995) and incidence rates (1975-1991), and also to discuss background factors possibly ascribable to the recent variation in mortality and incidence rates. The age-adjusted mortality rate (adjusted by the 1985 model population) has increased by approximately 9-fold in both males (from 1.4 to 12.5 per 100,000 population) and females (from 0.8 to 6.8 per 100,000 population) between 1950 and 1995. But it began to level off in both sexes since 1985. The age-adjusted incidence rate has remained plateau in both sexes, but likely showed a downward trend since 1988 in females. The older age groups showed the most steep increasing gradient in both age-specific mortality and incidence rates in both sexes, whereas a little or no apparent increase was observed in young age groups. Diagnostic improvement and increased cigarette consumption were believed to be the two major factors contributing to the increased mortality and incidence rates in Japan, but further epidemiological studies will be required to clarify possible background factors for the recent levelling-off of the mortality and incidence rates.

Adult↗

PubMed1998

[The study on relationship between fetal blood flow velocity waveforms and cord blood gas analyses in normal full term pregnancy].

OBJECTIVE: To study the relationship between fetal blood flow velocity waveforms and cord blood gas values in normal full term pregnancy. METHODS: Fetal umbilical artery (UA) and middle cerebral artery (MCA) and abdominal aorta (AbAo) flow velocity waveforms were measured in 45 full term fetuses 24 hrs before selective cesarean section. Resistance index (RI) and pulse index (PI) were calculated, cord blood samples were obtained from the umbilical artery at cesarean section and blood gas values were measured immediately. RESULTS: (1) UA RI had a significant negative correlation with pH and PO2, and a positive correlation with PCO2. (2) MCA RI had a significant positive correlation with pH and PO2, and a negative correlation with PCO2. CONCLUSION: A Doppler study of fetal blood flow velocity waveforms would be a useful method in the evaluation of the fetal status in the uterus.

Aorta, Abdominal↗

PubMed1998

[Survey on breakfast-eating behavior among residents in Beijing, Guangzhou and Shanghai].

A survey of breakfast-eating behavior among residents in Beijing, Guangzhou and Shanghai was carried out in 1994-1995. The results showed that the breakfast-eating rates in three cities were 74.8%-90.5%. Subjects aged below 35 years skipped breakfast more often. "Time limiting" in the morning became the main cause of breakfast-skipping. Nearly half of subjects in three cities got their breakfast out of home. Moreover, compared with two years ago, the present rates of eating outside increased at various levels in three cities. Steamed bun, bread and congee were main foods consumed at breakfast. In addition, 39% to 56% of subjects often drank milk. Through this survey, the authors got an all-round understanding on breakfast-eating rates, eating outside rates and variety of food consumed of residents in 3 cities. This survey will also provide a background for nutrition intervention and education in the future.

Adult↗

PubMed1998

[Inhibition effect of Swainsonine on the growth and metastasis of gastric cancer in vivo].

OBJECTIVE: To study the immunomodulating effect of Swainsonine (SW), an inhibitor of alpha-mannosidase II, and the inhibiting effect on the growth and metastasis of gastric cancer. METHODS: Nude mice with human gastric cancer xenograft orthotopically implanted into the gastric wall were fed with drinking water containing 3 mg/L SW for two days alternating with that containing no SW for two days until sacrificed eight weeks after tumor implantation. RESULTS: The mean tumor volume in the SW-treated group was significantly smaller than that of the control group (0.42 +/- 0.26 cm3 vs 1.60 +/- 0.36 cm3). Calculated by volume, the tumor growth was inhibited by 73.8%. Metastasis to the liver was observed in 20% and 80% of the SW-treated and control mice, while metastasis to the peritoneum was seen in 30% and 90% of SW-treated and control mice, respectively. The total number of splenic cells, and the NK cell activity both of PBL and splenic cells were all elevated. CONCLUSION: SW is effective in inhibiting tumor growth and metastasis of human gastric cancer in nude mice. Enhanced immune response, among other things, may be involved in the anti-tumor effect.

Adenocarcinoma↗

PubMed1998

[Experimental study of the effect of angiogenesis inhibitor TNP-470 on the growth and metastasis of gastric cancer in vivo].

OBJECTIVE: To study the effect of angiogenesis inhibitor TNP-470 on the growth and metastasis of gastric cancer in vivo. METHODS: Metastatic model simulating human gastric cancer was established by orthotopic implantation of histologically intact human tumor tissue into gastric wall of nude mice. TNP-470 was administered s.c. at doses of 0 mg/kg, 15 mg/kg, 30 mg/kg, 60 mg/kg every other day for eight weeks. Ten weeks after implantation, the mice were sacrificed and the tumor size measured and the presence of metastasis recorded. The microvascular density was examined by immunohistochemical staining with anti-human factor VIII antibody. RESULTS: Compared to the untreated controls, growth of the orthotopically implanted tumor was significantly reduced in size in mice treated with TNP-470 with an inhibition rate of 59.9%, 77. 0% and 84.9% at the dosage of 15 mg/kg, 30 mg/kg and 60 mg/kg, respectively. Tumor metastasis to the liver and peritoneaum was also significantly inhibited in a dose-dependent manner. The microvascular density was also decreased significantly in the treated mice. CONCLUSION: Angiogenesis inhibitor TNP-470 has strong inhibitory effect both on tumor growth and metastasis of human gastric cancer in nude mice.

Animals↗

PubMed1998

[The effect of antisense epidermal growth factor receptor RNA on the growth of human malignant glioma cells].

OBJECTIVE: To study the effect of antisense EGFR RNA on the growth of human malignant glioma cells. METHODS: An antisense EGFR expression vector was constructed and introduced into human malignant glioma cells. PCR analysis was used to determine which clones were successfully transfected with antisense EGFR constructs. Western blotting analysis was used to determine EGFR protein level in the transfected cells. The in vitro growth and their ability to grow in soft agar were studied. RESULTS: Western blotting analysis showed six clones stably expressing lower levels of EGFR protein. Antisense EGFR RNA was found to inhibit the proliferation of human malignant glioma cells and their ability to grow in soft agar. There was a negative correlation between the growth inhibiting effect of antisense EGFR and EGFR protein expression. CONCLUSION: These results demonstrate that EGFR play an pivotal role in human malignant glioma cell growth. Antisense EGFR can inhibit the growth of human malignant glioma cells.

Cell Division↗

PubMed1998

[HLA-DRB alleles polymorphism in susceptibility to asthma in Beijing Chinese].

OBJECTIVES: To investigate whether susceptibility or resistance to asthma associated with HLA-DRB alleles and analyze the relationship between HLA-DRB genes and clinical phenotype of asthma (TIgE, sIgE, BHR). METHODS: Using PCR-SSP(sequence-specific primer polymerase chain reaction), we tested the frequency distribution of HLA-DRB alleles in 50 asthmatic patients and 80 healthy volunteers from Beijing China. All patients had their serum TIgE, IgE antibody specific to house dust mite measured by RAST, bronchial responsiveness assessed by methacholine bronch-provocation (if FEV1% > or = 70%), and broncho-dilation measurement by inhaling salbutamol. RESULTS: There was significantly increased gene frequency of alleles DR6(13), DR52 in asthmatics compared with normal controls (17% vs 4.3%, P < 0.01; 50% vs 17.5%, P < 0.01), and RR was 7.55 and 4.7 respectively. The frequency of DR2(15), DR51 was lower in asthmatics than in controls (7% vs 18% P < 0.01; 2% vs 33.8% P < 0.01). The percentage of HLA haplotype DR6(13)-DR52 was higher in asthmatics than in healthy volunteers (20% vs 4%, P < 0.01, RR 6.4). 70% of individuals sharing DR6(13) gene and 56% of subjects carrying DR52 gene had elevated serum d1 sIgE antibody (> or = +4). There was no relationship between HLA-DRB alleles and total IgE, BHR. CONCLUSIONS: Alleles DR6(13), DR52 are significantly implicated in their susceptibility to asthma, at least they may be closely associated with this disorder. Conversely DR2(15), DR51 alleles might confer protection against asthma. Positive associations between DR6(13), DR52 and IgE response to d1 allergen are noted. HLA-DRB genes are particularly involved in regulating human atopic immune response.

Adult↗

PubMed1998

Effects of combined radiation and thermal burn injury on the survival of skin allograft and immune function in rats.

OBJECTIVES: To investigate the effects of combined radiation and thermal burn injury on the survival of skin allografts and to analyze the relationship between the prolongation of allograft survival and the changes of immune functions of the thymocytes and splenocytes in rats. METHODS: Wistar rats were irradiated with 3, 4, 5, 6 and 8 Gy of gamma rays. Thirty minutes after radiation, 15% TBSA III-degree burn was inflicted to the rats. Twenty-four hours after the burn injury, allografts were used to cover the burn wounds. In the 8 Gy group, 1 hour before skin grafting, the bone marrow cells (4 x 10(8)) from the same donor were also transplanted. All rats were carefully observed after injury. The rats with single radiation injury of 5 Gy gamma rays, with single burn injury and with combined radiation-burn injury were killed 3, 7, 10, 15 and 30 days after skin grafting for immunological assay and pathological study. RESULTS: All the allografts in the single burn group were rejected in 10 days. In the combined injury groups, the survival rates of the allografts in rats undergoing 3 and 4 Gy radiation were 20% and 30%, respectively. In the combined injury groups undergoing 5, 6 and 8 Gy radiation, the 10-day survival rates of the allografts were 69%, 88% and 100% respectively, and the 30-day survival rates in the three groups were 36%, 42% and 100% separately. The grafted allogenic skin, with normal epithelial cells and good vascularity, healed well with the recipient's skin. Hairs grew well from the allografts 30 days after grafting. Three, 7 and 15 days after allografting, in the single burn group, the proliferative activities of the thymocytes were 90%, 185% and 130% of the preinjury level, and the antibody forming capacities of the splenocytes were 200%, 171% and 300% of the preinjury level, respectively; in the combined injury groups, the proliferative activities were 6%, 99% and 91% of the preinjury level, and the forming capacities were 2%, 36% and 90% of the preinjury level. CONCLUSIONS: The survival rate of allograft in rats undergoing combined radiation and thermal burn injury rises with the increase in radiation dosage. The allograft covering single bun injury is severely rejected by immune reaction. The prolongation of the survival of allograft in combined injury group mainly results from radiation that suppresses immune functions.

Animals↗

PubMed1998

[Analysis of reasons failed focal debridement in 109 patients with spinal tuberculosis].

OBJECTIVE: To explore reasons failed focal debridement in treating spinal tuberculosis patients and methods to cope with them. METHOD: One hundred nine patients with spinal tuberculosis who failed initial focal debridement from 1987 to 1996 were reviewed. RESULT: The reasons of operational failure were found to be the use of unreasonable regimens and existence of drug resistant strains; inappropriate operational indication, approach and treatment during operation; lesions involving several vertebrae, skipping destruction and complicating with other kinds of extrapulmonary tuberculosis. CONCLUSION: The key to successful treatment of the disease is to choose appropriate operative indication and approach, discard spinal cord pressure and rebuild spinal stability on the basis of reasonable chemotherapy regimen.

Adolescent↗

PubMed1998

[Treatment of thoracolumbar tuberculosis complicated with paraplegia].

OBJECTIVE: To explore characteristics of thoracolumbar tuberculosis complicated with paraplegia, relationship between efficacy and approach of operation, and to discuss indication and applicability of conservative treatment. METHOD: Forty-eight cases with thoracolumbar tuberculosis complicated with paraplegia were classified into two groups. Thirty-two cases in the operational group were treated with extrapleural, extraperitoneal approach and transpleural, extraperitoneal approach. Sixteen cases in the nonoperational group were treated conservatively. RESULT: The recovered cases in the operational and the nonoperational groups respectively accounted for 75% and 88%. CONCLUSION: Thoracolumbar tuberculosis complicated with paraplegia can be cured by either operative or conservative treatment, and the efficacy of operation directly related with operational approach.

Adolescent↗

PubMed1998

[Comparison of three antituberculous drugs in serum and cold abscesses of patients with spinal tuberculosis].

OBJECTIVE: Pharmacokinetics of INH, RFP and OFLX in serum and cold abscesses of patients with spinal tuberculosis was analyzed to provide reference to choosing clinical therapeutic regimen. METHOD: The aspiration specimens of abscesses and venous blood were collected from 8 patients with spinal tuberculosis at 0.5, 0.75, 1.0, 1.5, 2.0, 4.0, 6.0, 9.0, 12.0, 16.0 and 24.0 h after administration of antituberculous drugs. The specimens were assessed by high performance liquid chromatography (HPLC). The data were processed with software 3P87. RESULT: The Cmax of INH, RFP and OFLX in serum were 10.87 +/- 7.09 micrograms/ml, 9.98 +/- 3.53 micrograms/ml, and 5.29 +/- 0.72 micrograms/ml, while the Cmax of INH, RFP and OFLX in cold abscesses were 2.84 +/- 1.63 micrograms/ml, 0.57 +/- 0.26 microgram/ml and 3.19 +/- 1.29 micrograms/ml respectively. CONCLUSION: After administration, the Cmax of INH and OFLX in the cold abscesses of patients with spinal tuberculosis, reached the level beyond their MIC and appeared and disappeared more slowly than that in the serum; RFP was not easy to permeate into the cold abscesses, the Cmax of RFP in the cold abscesses just reached its MIC.

Abscess↗