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Biomedical subjects

L Shi

Publications and source records attributed to L Shi.

At least 145 records · Page 8Linked to original sources
PubMed1999

Effects of diagnostic levels of color Doppler ultrasound energy on the cell cycle of newborn rats.

Our objective was to evaluate the safety of diagnostic levels of color Doppler ultrasound energy in the field of obstetrics and to provide the experimental data for its clinical application. After insonating pregnant rats with diagnostic levels of color Doppler ultrasound energy, we studied the cell cycles of the newborn rats by flow cytometry and factorial analysis. We found that the deoxyribonucleic acid content was not affected in any phase of the cell cycle in newborn rats by any of the different insonation times and frequencies.

Animals↗
PubMed1999

Income inequality, primary care, and health indicators.

BACKGROUND: The significant association of income inequality with a variety of health indicators is receiving increasing attention. There has also been increasing evidence of a link between primary care and improved health status. We examined the joint relationship between income inequality, availability of primary care, and various health indicators to determine whether primary care has an impact on health indicators by modifying the adverse effect of income inequality. METHODS: Our ecologic study used the US states as the units of analysis. In analyzing the data, we looked at the associations among income inequality, primary care, specialty care, smoking, and health indicators, using Pearson's correlation coefficients for intercorrelations and the adjusted multiple regression procedure. To examine the effect of inequality and primary care on health outcome indicators, we conducted path analyses according to a causal model in which inequality affects health both directly and indirectly through its impact on primary care. RESULTS: Our study indicates that both primary care and income inequality exerted a strong and significant direct influence on life expectancy and total mortality (P <.01). Primary care also exerted a significant direct influence on stroke and postneonatal mortality (P <.01). Although levels of smoking are also influential, the effect of income inequality and primary care persists after controlling for smoking. Primary care serves as one pathway through which income inequality influences population-level mortality and at least some other health outcome indicators. CONCLUSIONS: It appears possible that a primary care orientation may, in part, overcome the severe adverse effects on health of income inequalities.

Cerebrovascular Disorders↗
PubMed1999

Effects of storage and cooking on the iodine content in iodized salt and study on monitoring iodine content in iodized salt.

In order to ensure that the intake of iodine from iodized salt is adequate, the effects of cooking, storage and iodination on iodine content in iodized salt have been studied. For monitoring the analytical performance, a quality control examination was also undertaken. The loss of iodine was greater when salt was stored in plastic bag than in glass bottle. The loss was greater in fortified salt stored at 37 degrees C and under 76% humidity than in that at 20-25 degrees C and under lower humidity. The retention of iodine varied with the kind of foods and also was influenced by the water content of cooked food. In general, the retention of iodine during cooking varied considerably (from 36.6% to 86.1%). The iodine concentration in salts varied greater from 3.0 to 100.3 mg/kg in salt for markets, and from 0 to 90.0 mg/kg in salts for households. 48.3% of samples from markets were found to be in compliance with national standards (30-50 mg/kg), and 72.0% of samples from households were in compliance with national standard (20-50 mg/kg). Analytical data collected from 8 of the cooperative laboratories for an analytical reference material showed a 95% confidence interval of the population mean for both precision and accuracy, falling within X +/- 2SD and passing quality control examination.

Food Preservation↗
PubMed1999

A profile of women CEOs/administrators in community and migrant health centers.

Most of the current research on women executives has focused on models in which few women achieve the highest position (e.g. hospital CEOs). This article looks at the nation's Community and Migrant Health Centers where substantial numbers of women hold the highest executive position. A national profile of women Community and Migrant Health Centers (C/MHCs) Chief Executive Officers/Administrators is provided in terms of their personal and work characteristics, as well as their values and beliefs regarding successful C/MHC attributes and important managerial practices. The study compares C/MHC Chief Executive Officers/Administrators based on gender. The study found that 41 percent of the CEO/Administrators were women and that they shared similar values and beliefs about functions/critical managerial factors and managerial characteristics of C/MHCs with their male colleagues. However, the study did find a comparable salary differential of over $11,000 in favor of male Chief Executive Officers/Administrators. The article reviews the literature of female executives in health care and concludes with recommendations for further study using the C/MHCs CEO/Administrators as a model study population.

Community Health Centers↗
PubMed1999

Differences in the role and administrative relationships of medical directors in community and migrant health centers.

This study examined differences in medical directors of Community and Migrant Health Centers (C/MHCs) in the United States based on the size of the center, including demographics, job characteristics, roles, and their relationship with C/MHC administrators and governing boards. Data for this analysis came from a 1996 cross-sectional survey of Community and Migrant Health Centers medical directors. A total of 411 centers (68.3% surveyed) responded to the survey including 240 rural centers (67.4%) and 171 urban (68.7%) centers. Small centers were categorized as those with three or fewer physicians (n = 136), medium centers had more than three but less than eight ETE physicians (n = 14), and large centers had eight or more ETE physicians (n = 109). Several differences were found regarding the medical directors' roles and relationships with the administrator and governing boards on the size of the center. Large C/MHC medical directors had more autonomy than did small and medium C/MHC medical directors including in the areas of managing clinical staff, the budget, and strategic planning activities. They spent more time cultivating community resources than small and medium center counterparts and were more likely to possess the management skills needed in their role than do those in small and medium centers. They also reported a stronger working relationship with the C/MHC administrator and had more input with the C/MHC board than small or medium medical directors.

Ambulatory Care Facilities↗
PubMed1999

[Roles of bifidobacterium on prevention of experimental colorectal carcinoma and induction of apoptosis].

OBJECTIVE: To explore the effect of bifidobacterium adolescence on prevention from experimental colorectal carcinoma and its antitumor mechanism. METHODS: An animal model of nude mouse tumor transplanted from colorectal carcinoma was set up. Bifidobacteria adolescence were intraperitoneally injected into nude mice in advance. The growth rate, ultrastructure, density of apoptotic cells, rate of bcl-2 and bax oncoprotein expression and its positive cell density in transplanted tumor of nude mice from colorectal carcinoma were investigated by employing transmission microscopy, in situ end labeling technique and immunohistochemical staining. RESULTS: The growth rate of transplanted tumors from colorectal carcinoma in the group with bifidobacterium prevention was slower than that in the control group. Many tumor cells at varied apoptotic stages could be observed in transplantation tumor tissue in the bifidobacterium prevention group and their density of apoptotic cells, rate of bcl-2 and bax oncoprotein expression and its positive cell density were significantly higher in the group with bifidobacterium prevention, as compared with the control group (P < 0.01). But, expression rate of bcl-2 oncoprotein turned contrary to that of bax oncoprotein. CONCLUSION: Bifidobacteria adolescence could markedly prevent from occurrence and development of colorectal carcinoma in vivo and induce apoptosis of tumor.

Animals↗
PubMed1999

[Determination of beta-carotene in tobacco by HPTLC].

This paper reports the high performance thin-layer chromatography (HPTLC) determination of beta-carotene in tobacco. The developer used was V(benzene):V(acetone) = 4:1. The detection wavelength was 450 nm. The linear range and the detectable limit of the method were 50 ng-0.5 microgram and 20 ng per spot of beta-carotene respectively. The method has been proved to be simple, sensitive, accurate and reproducible.

Chromatography, Thin Layer↗
PubMed1999

[Endoscopic pituitary tumor surgery by nasal cavity and sphenoid sinus].

OBJECTIVE: For reducing surgical trauma to patients of pituitary tumor. METHOD: 12 patients of pituitary tumor were treated with endoscopy by nasal cavity and sphenoid sinus under general anaesthesia. RESULT: Except one died of bleeding within cranial cavity after operation, the rest recovered smoothly without severe complications. During 7 months to one and half year follwing-up, the function of endocrine in 9 cases resumed to normal and 8 of their vision improved to some extent. CONCLUSION: The good illumination and clear visual field under endoscopy could improve the accuracy and security of operation and minimize the injury to normal tissue. But for large or recurrent tumors, this approach should be selected carfully.

Adult↗
PubMed1999

[Expression and clinical implication of multidrug resistance gene and multidrug resistant-associated protein gene in patients with hypopharyngeal squamous cell carcinoma].

OBJECTIVE: To study the relationship between the expression of MDR-1 mRNA/P-glycoprotein (P-gp). MRP mRNA and the clinical pathological characteristics of the patients with hypopharyngeal squamous cell carcinoma. METHODS: Reverse transcription polymerase chain reaction(RT-PCR) assay was used to detect the expression of MDR-1 mRNA and MRP mRNA in 25 specimens of the untreated advanced hypopharyngeal carcinoma. Meantime, immunohistochemistry SABC technique was used to test P-gp in 60 tumor specimens. RESULTS: The positive expression rates of MDR-1mRNA and P-gp in hypopharyngeal carcinoma were 48 percent (12/25) and 38.3 percent(23/60), respectively. There was a correlation between expression of MDR-1 mRNA and its product P-gp in 25 patients using RT-PCR assay(P < 0.05). The positive expression rate of MRP mRNA was 52 percent (13/25), which was significantly related to metastases of cervical lymph node (P < 0.01). CONCLUSION: Forty-eight percent of the untreated patients with hypopharyngeal carcinoma presented positive expression of MDR-1 mRNA, which was correlated with its gene product P-gp. The expression of MRP mRNA was associated with increased tumor dissemination and metastases.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1998

[Cytogenetic study in eight cases of Fanconi anemia].

OBJECTIVE: To study the clinical, hematological and cytogenetical characteristics in Fanconi anemia (FA). METHODS: Culture the peripheral lymphocytes with Mitomycin C (MMC) induction to count the chromosome breakages and to count the sister chromatid exchanges (SCE) in FA. RESULTS: The clinical and hematological manifestations in FA varied at all. Spontaneous chromosome break and MMC induced break in FA were significantly higher than those in normal. Spontaneous and induced SCE were also higher in FA. CONCLUSION: Owing to genetic heterogeneity in FA, the phenotypes in FA are diversified also. So, chromosome breakage study is a very important method in the diagnosis of FA, and gene complementation analysis may identify which complementation group the patient carries.

Adolescent↗
PubMed1998

[Effects of cooking methods on iodine content in iodized salt].

Effects of cooking methods and variety of foods on the retention of iodine content in food with iodized salt were studied. Vegetables from market and usual cooking methods were selected, including procedures of various cooking methods. The samples were fixed by potassium carbonate, ashed with zinc sulfate at 550 degrees C, then determined by colorimetric method with Ce-As-I catalytical reaction. The different cooking methods had different effects on the retention of iodine, in general, the retention of iodine by stewing of steaming was higher than by stir-frying. The effect of various vegetables on the retention of iodine was also different. The retention of iodine after stir-frying was 84.2%, 56.9%, 44.5%, 36.6% for fruit-bearing vegetables, leafy vegetables, roots and beans. The retention of iodine after stewing was 66.1%, 53.4%, 47.0%, and 43.2% for fruit-bearing vegetables, roots, beans and meat. The stability of organic iodine in food is higher than that of inorganic iodine.

Cooking↗
PubMed1998

Rational design and combinatorial evaluation of enzyme inhibitor scaffolds: identification of novel inhibitors of matrix metalloproteinases.

The discovery of a novel series of heterocyclic matrix metalloproteinase (MMPs) inhibitors is described. Published crystal structures of peptidyl hydroxamates bound to MMPs were the basis for the rational design of diketopiperazine (DKP) inhibitors. Combinatorial libraries were prepared and evaluated for their ability to inhibit collagenase-1, stromelysin-1, and gelatinase-B substrate hydrolysis. Deconvolution of active pools resulted in the identification of potent inhibitors (IC50's < 100 nM) of collagenase-1 and gelatinase-B, with the most potent inhibitor exhibiting an IC50 of 30 nM against collagenase-1. A description of the combinatorial evaluation process, as well as initial SAR interpretation for this novel series, is provided.

Diketopiperazines↗
PubMed1998

The detection of enzyme activity following sodium dodecyl sulfate-polyacrylamide gel electrophoresis.

More than a hundred different enzymes impinging on aspects of cell function ranging from carbohydrate and lipid metabolism to signal transduction and gene expression to biomolecule degradation have been detected by the assay of their enzymatic activities following SDS-PAGE. The strategies by which this has been accomplished are as varied as the enzymes themselves and offer testimony to the creativeness and ingenuity of life scientists. Assay of enzyme activity following SDS-PAGE is well adapted to identifying the source of catalytic activity in a heterogeneous protein mixture or a heterooligomeric protein (20), or determining if multiple catalytic activities reside in a single polypeptide (60). The alliance of versatile enzyme assay techniques with the molecular resolution of SDS-PAGE offers a powerful means for meeting the increasing demand for the high-throughput screening arising from protein engineering, combinatorial chemistry, and functional genomics.

Animals↗
PubMed1998

Defects in regulation of apoptosis in caspase-2-deficient mice.

During embryonic development, a large number of cells die naturally to shape the new organism. Members of the caspase family of proteases are essential intracellular death effectors. Herein, we generated caspase-2-deficient mice to evaluate the requirement for this enzyme in various paradigms of apoptosis. Excess numbers of germ cells were endowed in ovaries of mutant mice and the oocytes were found to be resistant to cell death following exposure to chemotherapeutic drugs. Apoptosis mediated by granzyme B and perforin was defective in caspase-2-deficient B lymphoblasts. In contrast, cell death of motor neurons during development was accelerated in caspase-2-deficient mice. In addition, caspase-2-deficient sympathetic neurons underwent apoptosis more effectively than wild-type neurons when deprived of NGF. Thus, caspase-2 acts both as a positive and negative cell death effector, depending upon cell lineage and stage of development.

Amyotrophic Lateral Sclerosis↗
PubMed1998

Antigen processing and autoimmunity. Evaluation of mRNA abundance and function of HLA-linked genes.

Quantitative defects in the density of conformationally correct human lymphocyte antigen (HLA) class I complexes on the surface of lymphocytes are apparent in patients with diverse HLA-linked autoimmune diseases, including Type I diabetes and Sjögren's syndrome. First, HLA class I expression was investigated in individuals with two rare and genetically divergent polyglandular autoimmune diseases. Polyglandular failure patients whose disease showed HLA linkage, but not those whose disease was not HLA linked, exhibited decreased HLA class I expression on the surface of their lymphocytes as well as a reduced abundance of transcripts of the HLA-linked genes Tap1 and Tap2, both of which encode proteins that contribute to HLA class I processing. Second, lymphocytes from patients with insulin-dependent diabetes mellitus (IDDM), Sjögren's syndrome, Graves' disease, and Hashimoto's disease showed varying degrees of decreased abundance of mRNAs that encode Tap1, Tap2, Lmp2, or Lmp7 (the latter two proteins also contribute to HLA class I processing). Third, in twins discordant for IDDM, reduced transcript abundance was preferential to diabetic subjects. Fourth, functional assays of isolated diabetic proteasomes, the peptide cutting complex containing LMP2 and LMP7 proteins, revealed altered peptidase activity. These data suggest that defective transcription of HLA class I-processing genes could contribute to the quantitative defect in cell-surface expression in autoimmune lymphocytes of HLA-controlled disease.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1998

Interactions of the borna disease virus P, N, and X proteins and their functional implications.

Borna disease virus (BDV) causes persistent central nervous system infection and behavioral disturbances in warm-blooded animals. Protein interaction studies were pursued to gain insight into the functions of the putative nucleoprotein (N), phosphoprotein (P), atypical glycoprotein (gp18), and X protein (X) of BDV. Coimmunoprecipitation experiments indicated that N and P, and P and X, form complexes in infected cells. Two-hybrid analyses confirmed interactions between P and P, P and X, and P and N, but not between P and gp18, N and gp18, X and gp18, or X and N. Analysis of P truncation mutants identified three nonoverlapping regions important for oligomerization (amino acids (aa) 135-172), and binding to X (aa 33-115) or N (aa 197-201). Coexpression of X stimulated oligomerization of P but decreased N-P complex formation. Immunocytochemistry of transfected noninfected CHO cells demonstrated that the distribution of X is dependent upon the presence of P-X expressed alone was found predominantly in the cytoplasm whereas coexpression of X and P resulted in nuclear localization. Immunocytochemistry of infected cells revealed nuclear colocalization of P and X. Interactions of P, N, and X may have implications for regulation of BDV transcription/replication and ribonucleoprotein assembly.

Animals↗