Biomedical subjects

R Hu

Publications and source records attributed to R Hu.

At least 37 records · Page 2Linked to original sources

PubMed2001

[Polycystic ovaraian syndrome and hyperinsulinemia].

OBJECTIVE: To identify the relationship between polycystic ovarian syndrome and hyperinsulinemia. METHODS: Age, body height, body weight, serum estradiol, progesterone, testosterone, follicle stimulating hormone (FSH), luteinizing hormone (LH), prolactin (PRL), triiodothyronine (T3), tetraiodothyronine (T4), insulin, oral glucose tolerance test (OGTT), and cortisol were measured in 28 patients with polycystic ovarian syndrome (PCOS). RESULTS: Sxiteen patients (57.1% of total) had hyperinsulinemia. Among them one patient was found diabetic. No difference was noted in age, height, body weight, body mass index, serum estradiol, progesterone, testosterone, FSH, LH, PRL, T3, T4, cortisol, and glucose of OGTT between hyperinsulinemia and non-hyperinsulinemia patients. However the LH/FSH ratio (2.4 +/- 1.5) in hyperinsulinemia patients was significantly higher than 1.2 +/- 0.6 in non-hyperinsulinemia patients (P = 0.0125). In addition, the results showed that the fasting serum insulin, insulin after OGTT, the insulin/glucose ratio at 30, 120 minutes, 180 minutes, the area under curve of and the insulin, insulin resistant index (IRI) were higher in hyperinsulinemia pateints than in non-hyperinsulinemia patients respectively. Furthermore, the fasting insulin level, insulin/glucose ratio were found to be negatively related to insulin sensitivity index and positively related with beta-cell functioning index. CONCLUSION: Hyperinsulinemia and insulin resistance accompany with some of the PCOS patients in China. Further investigations will be necessary to clarify the relevant mechanisms.

Adult↗

PubMed2001

[Fluorescence quenching method for the determination of p-hydroxyphenylpyruvic acid].

A fluorescence quenching method for the determination of p-hydroxyphenylpyruvic acid with trytophan in the medium pH 11.01 NH3-NH4Cl is studied. The calibration curve is linear for p-hydroxyphenylpyruvic acid from 0 to 15 micrograms.mL-1 with lambda ex/lambda em = 285/356 nm. The detection limit is 0.37 microgram.mL-1. Twenty replicate determinations of solutions containing 10 micrograms.mL-1 p-hydroxyphenylpyruvic acid show a relative standard deviation of 1.2%. This method can be applied to the determination of p-hydroxyphenylpyruvic acid in serum with satisfactory results.

Calibration↗

PubMed2001

[The XPS of complexes of zinc salts with alpha-amino acids].

The XPS of solid complexes of ZnCl2/ZnSO4/ZnOAc2 with alpha-Met/His have been investigated. The results indicate that Zn2+ coordinate with O atom of carboxyl group and N atom of alpha-amino. The N atom of imidazolyl also participates the coordination. While the S atom of methylthio does not coordinate with Zn2+. This results are consistent with IR analyses. The structures of those complexes are presumed.

Amino Acids↗

PubMed2000

Should calcaneal fractures be treated surgically? A meta-analysis.

A MEDLINE search from 1980 through 1996 revealed 1845 articles dealing with calcaneal fractures. Six of these articles that compared operative versus nonoperative treatment for displaced calcaneal fractures met the minimum criteria for inclusion in a meta-analysis. A statistical summary of information across the six articles revealed a trend for surgically treated patients to be more likely to return to the same type of work as compared with nonoperatively treated individuals. There also was a trend for nonoperatively treated patients to have a higher risk of experiencing severe foot pain than did operatively treated patients. Unfortunately, none of the other outcomes could be summarized formally across studies using statistical techniques because of variability in reporting across studies. Although the tendency was always for operatively treated patients to have better outcomes (reaching statistical significance in some of the articles), the strength of evidence to recommend operative treatment for displaced intraarticular calcaneal fractures remains weak. A large prospective randomized controlled trial should be able to answer this question.

Calcaneus↗

PubMed2000

Expression and regulation of a molecular marker, SPR1, in multistep bronchial carcinogenesis.

A small proline-rich protein, SPR1, is overexpressed in squamous metaplasia of bronchial epithelium. We studied the expression and regulation of SPR1 in a series of human bronchial epithelial cell lines representing a model of multistep bronchial carcinogenesis. These cell lines included a primary culture of tracheobronchial epithelial cells (HTBE), a papilloma virus-transformed tracheobronchial epithelial cell line (HBE1), a cell line selected from HBE1 by a tobacco carcinogen and a phorbol ester (HBE1-C), a simian virus-transformed bronchial epithelial cell line (BEAS-2B), and a lung carcinoma cell line (H460). Different tumorigenic potentials of these cell lines were indicated by graded levels of telomerase activity. Concomitant with squamous transformation, there was an increase in SPR1 expression in HTBE, HBE1, and HBE1-C that was reversible by vitamin A. With progression of tumorigenicity, there was a marked reduction in SPR1 expression in BEAS-2B and a total loss of expression in H460. In these latter cell lines representing advanced malignant transformation, there was a loss of up- and downregulation, respectively, by the phorbol ester and vitamin A. Transfection study with chimeric constructs of the SPR1 promoter and a reporter gene showed that the dysregulation of SPR1 expression in malignant transformation was a result of perturbation of the basal and enhancer elements of the first 162 nucleotides in the 5'-flanking promoter region of the SPR1 gene. These findings suggest an association of transcriptional dysregulation of the SPR1 gene with multistep bronchial carcinogenesis.

Animals↗

PubMed2000

Relationship between weights of the engorged nymphal stage and resultant sexes in Ixodes scapularis and Dermacentor variabilis (Acari: Ixodidae) ticks.

The relationship between weights of the nymphal stage and their resultant sexes in Ixodes scapularis Say and Dermacentor variabilis (Say) was examined under laboratory conditions. Nymphs were fed to repletion on laboratory white mice, weighed individually, and held until they molted. Fully engorged I. scapularis nymphs that subsequently molted to females weighed between 3.8 and 6.4 mg (n = 64). Those nymphs that molted to males weighed between 2.0 and 3.2 mg (n = 57). Body weights of engorged nymphs that became females were significantly greater than those of nymphs that became males (P < 0.05). Similarly, the range of body weights of engorged D. variabilis nymphs that subsequently became females was 9.1-15.1 mg (n = 32), whereas those nymphs that molted to males weighed between 3.9 and 13.0 mg (n = 39). Body weights of engorged nymphs that became females were significantly greater than those of nymphs that became males (P < 0.05). This suggests that nymphs of both species that become females presumably imbibe more blood than those that became males.

Animals↗

PubMed2000

Winter ectoparasites of mammals in the northeastern piedmont area of Georgia.

Twenty-three species of ectoparasites were recovered from 10 species of mammals (89 individuals) in Mistletoe State Park, Columbia County, Georgia, during three winter months of 1998. The collection consisted of 9 species of fleas, 6 mites, 4 sucking lice, 3 ticks, and 1 mammal-associated beetle. Some rarely-collected arthropods were recorded including the ctenophthalmid fleas, Doratopsylla blarinae C. Fox and Epitedia cavernicola Traub, the laelapid mite, Echinonyssus blarinae (Herrin) (first records from Georgia for these three ectoparasites), and the leptinid beetle, Leptinus orientamericanus Peck (second record for Georgia). Varying degrees of host-specificity were exhibited by the 23 species of ectoparasites. Because relatively few mammal ectoparasite surveys are completed during the winter months, some seemingly rare species may, in reality, be more common at this time of year.

Animals↗

PubMed2000

Rodent ectoparasites from two locations in northwestern Florida.

From Feb.-Apr. 1999, 19 species of ectoparasitic arthropods (2 sucking lice, 4 fleas, 4 ticks, 2 mesostigmatid mites, 5 chiggers, 2 fur mites) were recovered from 106 rodents belonging to 5 species (cotton mouse, Peromyscus gossypinus, n = 64; cotton rat, Sigmodon hispidus, n = 23; eastern woodrat, Neotoma floridana, n = 9; golden mouse, Ochrotomys nuttalli, n = 9; eastern gray squirrel, Sciurus carolinensis, n = 1) at Tall Timbers Research Station, Leon County, Florida. During the same period, 13 species of ectoparasites (2 sucking lice, 1 flea, 3 ticks, 3 mesostigmatid mites, 2 chiggers, 2 fur mites) were recovered from 57 rodents belonging to 3 species (S. hispidus, n = 40; black rat, Rattus rattus, n = 16; S. carolinensis, n = 1) from Panama City, Bay County, Florida. Noteworthy ectoparasite records include Ixodes minor from both sites, which extends the known geographical range of this tick, and Stenoponia americana from Tall Timbers that represents the second documented Florida record of this flea. Potential tick vectors (Dermacentor variabilis and Ixodes scapularis) of zoonotic pathogens (Rickettsia rickettsii and Borrelia burgdorferi) were collected at both sites. On S. hispidus, fleas were more prevalent at Tall Timbers but sucking lice, chiggers, ticks, mesostigmatid and listrophorid mites all were more prevalent at the Panama City site. Arthropods recovered from arboreal nests (n = 3) of O. nuttalli at Tall Timbers included 3 species of ectoparasites (1 tick, 2 laelapid mites).

Animals↗

PubMed2000

[New full length cDNA cloned from normal pituitary and pituitary tumors].

OBJECTIVE: To clone new full length cDNA from normal pituitary and pituitary tumors. METHODS: cDNA libraries of human normal pituitary and pituitary tumors were constructed, and large-scale sequencing and bioinformatics were used. Silico cloning and rapid amplification of cDNA ends (RACE) were also used. RESULTS: 67 new full length cDNAs were cloned: 41 were cloned from normal pituitary, and 26 from pituitary tumors. Of the 67 cDNAs, 16 were related with endocrine function; at least 2 with a classical signal peptide were secretory protein, and 3 with classical transmembrane domains were transmembrane protein. Among the 5 cloned new full length cDNAs involved in signal transduction pathway of hormone, at least 2 participated in signal transduction pathway of receptors with tyrosine kinase activition. CONCLUSION: During short time, 67 new full length cDNA were cloned from normal pituitary and pituitary tumors by large-scale producing expressed sequence tags. Some of them may play an important role in the regulation of physiological and pathological processes of pituitary.

Cloning, Molecular↗

PubMed2000

[Community -based comprehensive prevention and control of hypertension in China (CCPACH Study)-prevalence and epidemiological characteristics in urban and rural area].

OBJECTIVE: To understand the epidemiological features and prevalence of essential hypertension in the rural communities. METHODS: A community-based survey on essential hypertension was carried out in urban and rural areas involving 280,000 population. RESULTS: The prevalence rate of hypertension in age 35 years and over was 31.7% and 32.9% in urban and rural respectively; the average age of the patients' in urbans was significantly higher than in rural areas. Among non-hypertensive cases, more than 50% of the population having risk factors of hypertension in both urban and rural areas. Rates of treatment and control awareness of hypertension were 56.3%, 26.8% and 4.4% respectively in urban; comparing to 40.3%, 17.5% and 2.6% respectively, in the rural areas. More than half of the diagnosed patients before survey did not take antihypertensive medicine for treatment in both areas. The proportions the classification of hypertension were similar in both areas with majority of them, mild and isolated systolic hypertension. CONCLUSIONS: It was demonstrated that there is an urgent need to carry out comprehensive prevention and control for hypertension in urban and rural area.

Adult↗

PubMed2000

[Isolation and phenotypic analysis of lamina propria mononuclear cells from colonoscopic biopsy specimens].

This study was directed to the method of isolation of lamina propria mononuclear cells (LPMC) from mucosal biopsy specimens and the phenotypic analysis of the cells. Ten biopsy specimens, taken individually from 8 patients with ulcerative colitis (UC), 5 normal controls and 22 patients with colorectal cancer, were collected to compare the factors that influence isolation and cell yield and to analyze the lymphocyte subsets by means of two-color flow cytometry. LPMC yield averaged 10(6) with a viability of more than 95% in UC, twice the yields in other two groups. The percentages of total T, B cells in three groups were similar (P > 0.05). When the UC group was compared with the other two groups, a significantly higher proportion of CD3(+)-CD4(+)-T cell (49.98% vs 37.54% and 37.25%, P < 0.01) was noted, whereas a lower proportion of CD3(+)-CD8(+)-T cell (23.64% vs 31.52% and 31.07%, P < 0.01) was observed. These data showed that the yield and viability of LPMC isolated from biopsy specimens were good enough for a phenotypic or functional analysis, which might be helpful to mucosal immune research on gut disorders, such as UC.

Biopsy↗

PubMed1999

Divergence of binding, signaling, and biological responses to recombinant human hybrid IFN.

Three human IFN-alpha hybrids, HY-1 [IFN-alpha21a(1-75)/alpha2c(76-165)], HY-2 [IFN-alpha21a(1-95)/alpha2c(96-165)], and HY-3 [IFN-alpha2c(1-95)/alpha21a(96-166)], were constructed, cloned, and expressed. The hybrids had comparable specific antiviral activities on Madin-Darby bovine kidney (MDBK) cells but exhibited very different antiproliferative and binding properties on human Daudi and WISH cells and primary human lymphocytes. Our data suggest that a portion of the N-terminal region of the molecule is important for interaction with components involved in binding of IFN-alpha2b while the C-terminal portion of IFN is critical for antiproliferative activity. A domain affecting the antiproliferative activity was found within the C-terminal region from amino acid residues 75-166. The signal transduction properties of HY-2 and HY-3 were evaluated by EMSA and RNase protection assays. Both HY-2 and HY-3 induced activation of STAT1 and 2. However, HY-2 exhibited essentially no antiproliferative effects at concentrations that activated STAT1 and 2. Additionally, at concentrations where no antiproliferative activity was seen, HY-2 induced a variety of IFN-responsive genes to the same degree as HY-3. RNase protection assays also indicate that, at concentrations where no antiproliferative activity was seen for HY-2, this construct retained the ability to induce a variety of IFN-inducible genes. These data suggest that the antiproliferative response may not be solely directed by the activation of the STAT1 and STAT2 pathway in the cells tested.

Amino Acid Sequence↗

PubMed1999

Assignment of the heme axial ligand(s) for the ferric myoglobin (H93G) and heme oxygenase (H25A) cavity mutants as oxygen donors using magnetic circular dichroism.

UV-visible absorption and magnetic circular dichroism (MCD) data are reported for the cavity mutants of sperm whale H93G myoglobin and human H25A heme oxygenase in their ferric states at 4 degreesC. Detailed spectral analyses of H93G myoglobin reveal that its heme coordination structure has a single water ligand at pH 5.0, a single hydroxide ligand at pH 10.0, and a mixture of species at pH 7.0 including five-coordinate hydroxide-bound, and six-coordinate structures. The five-coordinate aquo structure at pH 5 is supported by spectral similarity to acidic horseradish peroxidase (pH 3.1), whose MCD data are reported herein for the first time, and acidic myoglobin (pH 3.4), whose structures have been previously assigned by resonance Raman spectroscopy. The five-coordinate hydroxide structure at pH 10.0 is supported by MCD and resonance Raman data obtained here and by comparison with those of other known five-coordinate oxygen donor complexes. In particular, the MCD spectrum of alkaline ferric H93G myoglobin is strikingly similar to that of ferric tyrosinate-ligated human H93Y myoglobin, whose MCD data are reported herein for the first time, and that of the methoxide adduct of ferric protoporphyrin IX dimethyl ester (FeIIIPPIXDME). Analysis of the spectral data for ferric H25A heme oxygenase at neutral pH in the context of the spectra of other five-coordinate ferric heme complexes with proximal oxygen donor ligands, in particular the p-nitrophenolate and acetate adducts of FeIIIPPIXDME, is most consistent with ligation by a carboxylate group of a nearby glutamyl (or aspartic) acid residue.

Alanine↗

PubMed1999

Distribution of epstein-barr virus antigenic sites on the carboxyl terminal end of ribonucleotide reductase against nasopharyngeal carcinoma serum antibodies using an immunoabsorption method.

In an attempt to clone and express proteins from the Epstein-Barr virus (EBV) cDNA library to be used as antigens in an enzyme-linked immunosorbent assay (ELISA) format to test against the antibodies found in the sera of nasopharyngeal carcinoma (NPC) patients, we have isolated and characterized three clones. All three clones expressed the same polypeptides of different lengths, which belong to the carboxyl terminal end of the large subunit of ribonucleotide reductase (RR) of the EBV genome. All three clones were found to be immunogenic and could be used in an IgA and IgG ELISA against the NPC sera with various degrees of sensitivity and specificity. Because the clones varied in length, this difference provides a simple system to determine where most of the antibody epitopes lies on the protein. We designed an immunoabsorption assay and a mathematical model to help map the segment of the polypeptide most immunogenic to 43 NPC patients. Results were unexpected: 77% of the patients were most immunogenic to region z, which was the smallest fragment among the three fragments studied. Fragment z was only 33 amino acids in length. Only 14% and 19% of patients showed the most immunogenic region in segment x and y, respectively. This variation could be due to major histocompatibility complex antigens. The patients could be divided into three groups based on the immunoabsorption assays, in which each group responded to a different immunodominant segment in the RR antigen. The largest group responded to an immunodominant segment, which was only 33 amino acids long. This domain was coded for by the gene fragment from nucleotide 78,129 to nucleotide 78,227 of the EBV genome. This segment of the protein would be suitable for further epitope mapping studies.

Amino Acid Sequence↗

PubMed1999

Solid phase microextraction of pesticide residues from strawberries.

A new solid phase microextraction method for the determination of pesticide residues in strawberries for 16 commonly used compounds was described. The strawberries were crushed and centrifuged. An aliquot of the well agitated aqueous supernatant (4 ml) was extracted with a fibre coated with polydimethylsiloxane (PDMS, 100 microns) for 45 min at room temperature. Identification and quantification were achieved using a gas chromatography-mass spectrometry (GC-MS) system and selective ion monitoring (SIM). The method was tested for the following pesticides: carbofuran, diethofencarb, penconazole, hexaconazole, metalaxyl, folpet, bromopropylate, dichlofluanid, alpha-endosulfan, beta-endosulfan, parathion ethyl, procymidone, iprodione, vinclozolin, myclobutanil and chlorothalonil. Limits of detection, repeatability and linearity for standard calibration in strawberries were obtained. Positive and negative effects of the matrix between the extracting solution of strawberries and water were observed. Stabilities of these compounds in the extracting solution of strawberries were determined. The solvent-free SPME procedure was found to be quicker and more cost effective than the solvent extraction methods commonly used.

Calibration↗

PubMed1999

Serum leptin levels and adiposity in adult Chinese: a preliminary observation.

OBJECTIVE: To establish normal serum leptin levels in Chinese and investigate the relationship between serum leptin levels and body fat, gender, age and androgen. METHODS: Serum leptin levels were measured in 77 lean (BMI < 25) and 28 overweight or obese (BMI > or = 25) subjects by a radioimmunoassay (RIA) method. RESULTS: The serum leptin levels in lean Chinese were 2.15 +/- 1.46 ng/ml in male and 7.85 +/- 3.60 ng/ml in female, which are similar to those of Caucasians, while in overweight or obese ones, the levels were 4.87 +/- 3.47 ng/ml and 16.59 +/- 6.92 ng/ml respectively, lower than those in Caucasians. A 2-3 times higher leptin concentrations were found in women than in men in both conditions. Even when the number of lean males was expanded to 79 subjects aged from 17-80 years, no significant leptin-age relationship was found. Despite 25% of obese subjects manifested a relative deficiency of leptin, as a whole, leptin levels in both men and women were significantly correlated with BMI (r = 0.69, P < 0.001 in male and r = 0.63, P < 0.001 in female). CONCLUSIONS: Serum leptin levels in Chinese lean people are similar to those in Caucasians and in both lean and obese groups, the leptin levels are correlated with BMI, suggesting that the great majority of the obese patients are resistant to endogenous leptin. Those who are relatively deficient of leptin may become a group of good candidates for leptin treatment in the future.

Adult↗

PubMed1999

[Dynamic effect of the blood glucose and insulin on serum leptin concentration during oral glucose tolerance test].

OBJECTIVE: To investigate the effects of internal change of plasma glucose and serum insulin levels on serum leptin concentrations during oral glucose tolerance test (OGTT) in normal subjects and type II diabetics (DM). METHODS: Plasma glucose, serum insulin and leptin concentrations were measured simultaneously in 50 age, sex and body mass index matched non-diabetic (non-DM) and 50 DM subjects who were undergoing OGTT. RESULTS: The fast serum leptin concentrations were (3.88 +/- 0.64) microg/L in DM males and (8.30 +/- 1.06) microg/L in DM females. Respectively they were (5.01 +/- 0.64) microg/L and (10.48 +/- 1.30) microg/L in non-DM group. No significant difference was revealed. Comparing with the non-DM group, the glucose curve was elevated and the insulin releasing curve was characterized by a low response and a delayed peak in DM group. As for the leptin releasing curve, both groups showed a decreasing trend, which seemed to be more evident in DM group. CONCLUSION: Leptin concentration does not increase with the release of insulin. On the contrary, it shows a diurnal rhythmic descending trend, suggesting that in vivo, the insulin effect on serum leptin concentration is relatively weak and not able to affect the day-time descending trend of leptin levels.

Blood Glucose↗

PubMed1999

[Expression of C-erbB-2 protein in breast cancer and its clinical significance].

In order to understand the expression of C-erbB-2 protein in breast cancer and its clinical significance, we examined the expression of C-erbB-2 protein in 106 breast carcinomas by using the immunohistochemical techniques LSAB. The results showed that the positive rate of C-erbB-2 expression was 63.21% (67/106). The overexpression of C-erbB-2 protein related negatively with survival. 81.63% of the cases with overexpression of C-erbB-2 protein survived < or = 5 years and 34.29% survived > 10 years. There were significant associations of C-erbB-2 overexpression with advanced clinical stage, high histological grade, and positive axillary node status in breast cancers. All of these findings suggested that overexpression of C-erbB-2 protein might be an important prognostic factor and the detection of C-erbB-2 protein might be arranged as a regular pathological examination in the cases of breast cancer.

Adult↗