Biomedical subjects

Hong Xiao

Publications and source records attributed to Hong Xiao.

53 records · Page 3Linked to original sources

PubMed2003

New approaches to genetic manipulation of mice: tissue-specific expression of ACE.

The renin-angiotensin system (RAS) plays a central role in body physiology, controlling blood pressure and blood electrolyte composition. ACE.1 (null) mice are null for all expression of angiotensin-converting enzyme (ACE). These mice have low blood pressure, the inability to concentrate urine, and a maldevelopment of the kidney. In contrast, ACE.2 (tissue null) mice produce one-third normal plasma ACE but no tissue ACE. They also have low blood pressure and cannot concentrate urine, but they have normal indices of renal function. These mice, while very informative, show that the null approach to creating knockout mice has intrinsic limitations given the many different physiological systems that no longer operate in an animal without a functioning RAS. To investigate the fine control of body physiology by the RAS, we developed a novel promoter swapping approach to generate a more selective tissue knockout of ACE expression. We used this to create ACE.3 (liver ACE) mice that selectively express ACE in the liver but lack all ACE within the vasculature. Evaluation of these mice shows that endothelial expression of ACE is not required for blood pressure control or normal renal function. Targeted homologous recombination has the power to create new strains of mice expressing the RAS in selected subsets of tissues. Not only will these new genetic models be useful for studying blood pressure regulation but also they show great promise for the investigation of the function of the RAS in complicated disease models.

Animals↗

PubMed2003

[Study on molecular epidemiology of Mycobacterium tuberculosis in Chinese army with PCR amplified fingerprinting methods].

OBJECTIVE: Typing of Mycobacterium tuberculosis strains and epidemiological studies in the army of southern China to provide scientific basis for prevention of pulmonary tuberculosis. METHODS: A rapid fingerprinting of M. tuberculosis strains method by polymerase chain reaction (PCR) with outward-directed primers that designed to the ends of the insertion sequence IS6110 was developed, and to analyze the relationship between the polymorphism of DNA fingerprinting and epidemiology of M. tuberculosis. RESULTS: One hundred and fifty-four M. tuberculosis detected were classified into eight types according to their characters of PCR amplified fingerprints. The main types were type I (36.4%), type II (31.8%), and type III (21.4%), while other types were less than 4 percentage. In those main type groups, patients aged 20 to 29 and 30 to 39 took up 31.8% and 27.9% respectively. For those main types, the distribution of those types in the first treated patients showed significant difference compared with that in the retreated patients, and the rate of drug-resistance was also statistically different. However, the distribution was not statistically significant to history of BCG vaccination and patients living in urban or rural area. The main drug-resistant strains were only Isoniazid-resistant or Rifampin-resistant strains, while the drug-resistant strains were 44.4%, 29.6% and 14.8% respectively in type I, type II and type III. CONCLUSION: PCR fingerprinting was a rapid, precise, sensitive, specific method to type M. tuberculosis, and could be used to study the epidemiology of tuberculosis; The prevalence of tuberculosis was primarily due to the transmission of type I, type II and type III in the army being studied from Southern China, to suggest that surveillance needs to be strengthened.

Adult↗

PubMed2003

[Effects of different application dosage of herbicide on rice production].

Investigations on the effects of different application dosage of Machete and Londax mixture to control weeds in paddy fields showed that applied common and double dosage could effectively control weeds, and the controlling effects exceeded 80% and 90%, respectively, while there were some inhibiting effects to height and branch number of rice, and some resistance of weed had appeared. Weed contest might make rice get some compensation in height and branch under the condition that no herbicide and half dosage were applied, but the rice yield was decreased 36.01% and 54.80%, respectively, mainly because of the decrease of the number of effective panicles and grain number per panicle. The narrow economic benefit of the herbicides should be high.

Crops, Agricultural↗

PubMed2003

Hemorrhagic fever with renal syndrome presenting with intrauterine fetal death. A case report.

BACKGROUND: Hantavirus infection in pregnancy is rare. Only 2 cases of hantavirus pulmonary syndrome have been reported in the English-language literature. We report a case of hemorrhagic fever with renal syndrome (HFRS) complicating pregnancy to alert clinicians to this rare possibility. CASE: A 29-year-old woman had experienced persistent, high fever for 6 days, no fetal movement for 2 days and frequent vomiting for 1 day before being referred to our department with the additional symptoms of headache, lumbodynia and orbital pain. On examination, she had a normal body temperature, flushing of the face, conjunctive congestion, pharyngeal congestion, bulbar conjunctive edema, severe jaundice, petechiae and ecchymosis at sites of venipuncture, deranged liver and renal function tests, heavy proteinuria and hematuria, and coagulation disturbance. The diagnosis of HFRS complicating pregnancy was made on account of the clinical picture and antihantavirus IgM titer of 1:20. The patient's condition quickly deteriorated, with frank hematuria, oliguria and finally anuria, together with shock. Hemodialysis was immediately commenced, and a stillborn, male infant, of 3,200 g, was delivered vaginally following combined induction 12 hours after hemodialysis. The fetus showed no obvious abnormalities, but the parents declined an autopsy. After hemodialysis and delivery, the patient recovered and was discharged 3 weeks later. The repeat titer for antihantavirus IgM was 1:80 10 days after presentation. CONCLUSION: HFRS is a rare complication of pregnancy. The symptoms are nonspecific. Early diagnosis and appropriate management are necessary to improve the maternal and fetal outcome. Clinicians should include this condition in the differential diagnoses when a combination of hematologic, hepatic, renal and gastrointestinal problems presents in pregnancy.

Adult↗

PubMed2003

Identification of hepatitis B virus vertical transmission from father to fetus by direct sequencing.

To identify the possibility of hepatitis B virus (HBV) vertical transmission from father to fetus, eight male HBV carriers whose wives were negative for any HBV marker and their eight aborted fetuses who had been infected with HBV in utero, were studied. S gene 451 approximately 660 nucleotide sequence of HBV in 6 cases of father/fetus pairs and C gene 2022 approximately 2321 nucleotide sequence in the other 2 cases of father/fetus pairs were amplified by nested polymerase chain reaction (NPCR), and sequenced. HBV DNA was detected in the semen and spermatid of male HBV carriers. The homologies of HBV sequences between father and fetus were very high. Six father/fetus pairs had the same subtype adw. The sequences of the fragment were identical between father and fetus in 4 cases. Especially in case 3, both father and fetus had the same point mutation, which caused an amino acid substitution at codon 126. The other two cases had point mutations in the fetus at nucleotide positions 491, 494, 546, 581 resulting in amino acid substitution at codons 113, 114, 131, 143. The C gene 2022 approximately 2321 nucleotide sequences in two cases were identical. There were eleven common point mutations between father and fetus, but those mutations did not cause phenotypic changes. Our finding suggested that HBV vertical transmission from father to fetus was present. A HBV carrier father may transmit the virus to his fetus by spermatid.

Adult↗

PubMed2003

[Study on DNA fingerprinting of Mycobacterium tuberculosis strains isolated in Southern Chinese army by IS6110-restriction fragment length polymorphism].

OBJECTIVE: To study the correlation between DNA fingerprinting of Mycobacterium tuberculosis (MTB) stains isolated from the Chinese army in the south and from local residents, and to investigate the molecular epidemiological characteristics of tuberculosis (TB) in the army, for the sake of TB prevention in the army. METHODS: MTB DNA was digested with restriction endonuclease PvuII and electrophoresed in agarose gel, after Southern Blotting, the membrane was hybridized with a 245 bp fragment of IS6110 which labeled [alpha(32)P]-dCTP as probe. Finally, a restriction fragment length polymorphism (RFLP) patterns was shown, and analyzed logestic with epidemiological data from the patients. RESULTS: A total number of 185 TB strains were detected and the IS6110 copy numbers ranged from 1 - 22. No significant difference was found in the IS6110 copy numbers between patients from army and local patients. IS6110 copy numbers of TB strains in army patients were centered in 6 - 20, however, with 7 - 20 copies in local TB patients. The TB strains were dispersed into 8 groups and the majority of TB strains in both army and local patients was centered in groups I, II, III. The distribution of DNA fingerprint for drug resistance TB strains was significantly different from those for sensitive strains. No different distribution of among groups was found regarding BCG history. CONCLUSIONS: The genetics of TB stains were roughly the same between the army patients and local ones, but there was a strong correlation in the gene levels. Data suggested that a close connection should be considered on TB prevention and treatment for TB patients in the army and local residents.

China↗

PubMed2003

[HBV C gene mutation in the transmission from father to infant].

OBJECTIVE: Hepatitis B virus (HBV) DNA was detected from infants whose mothers were negative for all HBV markers and the fathers were HBV carrier, the homology of HBV sequence of fathers and fetus was high, and HBV mutations concentrated on some points, and the transmission of HBV from father to fetus was also identified in some reports. The present study aimed to study HBV transmission from father to infant. METHODS: The study enrolled 16 pairs of fathers who were HBV carriers and infants whose mothers were negative for HBV markers. The infants had evidences for intrauterine HBV infection. The five HBV serum markers HBsAg, HBeAg, anti-HBe, anti-HBs, and anti-HBc were detected with ELISA. The positive results for HBsAg and/or HBeAg were regarded as markers of HBV infection. Amplification of HBV DNA was done using a nested PCR method. The first amplification was carried out using primer C1 (nt 2394-2370), and primer C3 (nt 1730-1754). The second amplification was carried out using primer C2 (nt 1955-1974) and primer C6 (nt 2348-2330). Both primers were designed to amplify the part of sequence coding for the hepatitis B C antigen. The size of the amplified fragment obtained by the nested PCR was expected to be 394 bp. The PCR products were electrophoresed on 1.5% agarose gels, which were then stained with ethidium bromide and observed with ultraviolet transillumination. When 394 bp specific band was detectable, the sample was designated positive. Then the positive samples were identified by dot blot. The second PCR products were extracted by phenol-chloroform and 70% ethanol precipitation, then resuspended in TE buffer (pH8.0), and used as the template for cloning. The template was connected into pGEM-T vector by ligase. The ligated products were cloned into fresh competent JM109 cells, and incubated for 90 minutes at 37 degrees C on roller drum. Finally several dilutions were plated on plates containing ampicillin, X-Gal and IPTG, and incubated at 37 degrees C overnight. The white colony on plates was used for identification by the nested PCR with the above primers. When the 394 bp band was detectable by electrophoresis of PCR products in 1.5% agarose gels, the colony was designated positive; a positive colony was incubated in LB medium for 8 to 12 hrs, then plasmid was extracted using the Wizard Plus SV Minipreps DNA Purification System Kit (Promega). The purified plasmid was sent to Beijing Saibaisheng Company for sequencing. The homology of HBV C nt 2022-2301 sequence was compared between fathers and infants. RESULTS: The homology of HBV C nt 2022-2301 sequence were 99% - 100% in 16 pairs of fathers and infants. The results were referred to the published sequence of HBV adw/adr clones, and the nucleic acid databases were searched for homology by using BLAST tool on Internet. HBV of the sixteen pairs of father/infant was closely related to the Japan strain (Genebank accession number AF121249), but there were still 17 more mutations at nucleotide positions 2029, 2034, 2044, 2059, 2078, 2095, 2104, 2154, 2161, 2169, 2189, 2201, 2233, 2251, 2284, 2288, 2293. Moreover the mutations at positions 2189, 2288 resulted in the substitution of the encoded amino acid (corresponding to amino acid positions 97 and 130, respectively), the other mutations at the position were nonphenotypic. The mutation of 2189, 2288 nucleotide of HBV C gene caused 97, 130 amino acid substitution for isoleucine to leucine and proline to threonine. The mutation of 2189, 2288 nucleotide of HBV C gene were detected in 6 (37.5%) of 16 pairs of fathers and infants. CONCLUSION: The HBV transmission from father to infants did exist. The main HBV C gene mutation strains also existed in the transmission.

Adult↗

PubMed2003

Types of hysterectomy. Comparison of characteristics, hospital costs, utilization and outcomes.

OBJECTIVE: To compare hospital costs, patient characteristics and outcomes of 3 hysterectomy techniques--abdominal, vaginal and laparoscopically assisted vaginal (LAVH). STUDY DESIGN: A cross-sectional analysis was performed using patients discharged from Florida hospitals in 2000 with hysterectomy as the primary procedure. To avoid differences due to unrelated complications, records indicating cancer or other major non-hysterectomy-related procedure were excluded from the analysis. A total of 23,191 records were used to compare the 3 techniques on hospital costs and length of stay, controlling for patient differences in complicating diagnoses and related procedures. RESULTS: Consistent with previous studies, patients undergoing LAVH had higher hospital costs, shorter lengths of stay and no difference in surgical complications from either vaginal or total abdominal hysterectomy, even after controlling for patient comorbidities. Other factors affecting hospital costs and length of stay were patient race, type of insurance, hospital ownership and location. CONCLUSION: LAVH is still more expensive than vaginal and total abdominal hysterectomy but offers a speedier recovery, with no measurable difference in the rate of complications. Further research is warranted to ascertain differences in readmission rates across the techniques and to investigate the process used to select which hysterectomy technique is used for a given patient.

Adult↗

PubMed2002

Solid-phase synthesis and investigation of benzofurans as selective estrogen receptor modulators.

A library of benzofurans was prepared by solid-phase synthesis methods, and several analogues were identified as potent ligands for the estrogen receptors ER-alpha and ER-beta, with some compounds having selectivity for ER-alpha. Analogues designed to more closely mimic Raloxifene were less effective. Certain benzofurans were effective in a bone pit assay, but were characterized as agonists in a MCF-7 breast tumor cell proliferation assay.

Benzofurans↗

PubMed2002

Novel variants related to TT virus distributed widely in China.

TTV is a DNA virus with high genetic heterogeneity. To investigate the novel isolates of the virus, blood samples were collected from subjects who lived in various parts of China and suffered from hepatitis or were asymptomatic carriers. Nested PCR was carried out to amplify a 3.2-kb fragment using primers deduced from the prototype TTV (TA278). The ten entire 3.2-kb nt sequences were aligned with isolate TA278, SANBAN, TUS01, and SENV retrieved from GenBank, and a phylogenetic tree was constructed by Neighbor-Joining method. The analysis indicated that five novel variants of the present study have not been described before, and all TTV-related isolates could be classified into three groups. The isolate TCHN-A, B and TUS01 were included in a group, and the remaining novel isolates together with SANBAN and TA278 clustered into another group, while SEN virus formed a distinct group. The genetic distances of the five novel variants were 0.5507-0.8476 to TA278, 0.4635-0.7877 to SANBAN, 0.6064-0.7834 to TUS01 and 0.6936-0.8236 to SENV. Of these novel variants, the ORF1 consisted of 426-772 aa and ORF2 of 141-156 aa. The nt identities of ORF1 and ORF2 between those variants and TA278, SANBAN, and TUS01 were 46.1-60.8 and 48.7-63.6%, and those of aa sequences were only 27.1-52.4 and 28.9-45.5%, respectively. The first 65 aa of ORF1 were rich in arginine and most conserved with homology of 56.5-70.0%. There was a hypervariable region from aa 286 to 403 with merely 17.7-27.0% of identity. Despite a low aa identity between TA278 and the variants, they have similar hydrophilicity profiles of ORF1. There were 2-10 N-glycosylation motifs found in these variants. In conclusion, despite the high divergence, sequences of all these isolates shared common genome organisation, ORF structure, hydrophilicity patterns, and some potential motifs with TTV prototype. It is suggested that various TTV and TTV-related isolates belong to a very large and complex family, which remains to be studied.

Base Sequence↗

PubMed2002

Functional characterization of alternatively spliced 5-HT2 receptor isoforms from the pharynx and muscle of the parasitic nematode, Ascaris suum.

Serotonin (5-HT) receptors play key regulatory roles in nematodes and alternatively spliced 5-HT2 receptor isoforms have been identified in the parasitic nematode, Ascaris suum. 5-HT2As1 and 5-HT2As2 contain different C-termini, and 5-HT2As1Delta4 lacks 42 amino acids at the C-terminus of the third intracellular loop. 5-HT2As1 and 5-HT2As2 exhibited identical pharmacological profiles when stably expressed in human embryonic kidney (HEK) 293 cells. Both 5-HT2As isoforms had higher affinity for 5-HT than their closely related Caenorhabditis elegans homolog (5-HT2Ce). This increased 5-HT affinity was not related to the substitution in 5-HT2As1 of F120 for Y in the highly conserved DRY motif found in the second intracellular loop of other 5-HT receptors, since a 5-HT2As1F120Y mutant actually exhibited increased 5-HT affinity compared with that of 5-HT2As1. As predicted, cells expressing either 5-HT2As1 or 5-HT2As2 exhibited a 5-HT-dependent increase in phosphatidylinositol (PI) turnover. In contrast, although 5-HT2As1Delta4 displayed a 10-fold higher affinity for 5-HT and 5-HT agonists than either 5-HT2As1 or 5-HT2As2, 5-HT2As1Delta4 did not couple to either PI turnover or adenyl cyclase activity. Based on RT-PCR, 5-HT2As1 and 5-HT2As2 were more highly expressed in pharynx and body wall muscle and 5-HT2As1Delta4 in nerve cord/hypodermis. This is the first report of different alternatively spliced 5-HT2 receptor isoforms from any system.

Alternative Splicing↗

PubMed2002

Combined hepatocellular-cholangiocarcinoma: a histopathologic, immunohistochemical, and in situ hybridization study.

Combined hepatocellular-cholangiocarcinoma (CHC) forms a small but significant proportion of primary liver carcinomas. However, its diagnostic features are not well established, and this has possibly contributed to the variability in its reported clinical outcome in the literature. Many such tumors with features intermediate between hepatocellular carcinoma and cholangiocarcinoma (CC) may have been considered CC in the past based on positivity for "biliary differentiation" cytokeratins and the lack of availability of highly sensitive and specific hepatocellular markers. The utility of in situ hybridization for albumin mRNA, a recently available sensitive and specific hepatocellular marker, has not been reported in CHC. We investigated 27 CHCs with regard to their histomorphologic spectrum and association of these morphologies with immunohistochemical staining for different cytokeratins (CK7, CK19, and CK20; AE1; Cam 5.2), epithelial membrane antigen, polyclonal carcinoembryonic antigen and alpha-fetoprotein, and in situ hybridization for albumin mRNA. All 27 tumors contained areas morphologically intermediate between hepatocellular carcinoma and CC (transitional-type tumors), and in each case such areas formed at least 25% of the tumor. Nine (33%) tumors showed areas with "antler-like" morphology, a feature not previously described in CHC. Twenty-two of 23 tumors (96%) showed positive signals on in situ hybridization for albumin mRNA. Positivity for both hepatocellular (albumin mRNA) and biliary (keratin immunohistochemical profile) markers confirmed the light microscopic impression of biphenotypic differentiation in these tumors. Immunohistochemical positivity for all cytokeratins (except CK7) and epithelial membrane antigen, as well as the expression of albumin mRNA by in situ hybridization, did not show significant differences between hepatocellular carcinoma and CC-like areas. Based on the cytokeratin profile and results on polyclonal carcinoembryonic antigen/alpha-fetoprotein alone, many such tumors would be classified as CC. However, the positivity for albumin mRNA by in situ hybridization proves that such an interpretation would not have been accurate. Clinically, CHCs showed many differences from pure hepatocellular carcinoma, including the absence of cirrhosis (0 of 27), rarity of serum hepatitis B or C marker positivity (4 of 27), and normal to only mildly elevated serum alpha-fetoprotein levels (median 187 ng/mL). The tumor followed an aggressive clinical course, with overall 3-and 5-year survival rates of 30% and 18%, and in the resected cases of 38% and 24%, respectively.

Adult↗

PubMed2002

Antineutrophil cytoplasmic autoantibodies specific for myeloperoxidase cause glomerulonephritis and vasculitis in mice.

Antineutrophil cytoplasmic autoantibodies (ANCAs) are identified in the circulation of approximately 80% of patients with pauci-immune necrotizing and crescentic glomerulonephritis and systemic small vessel vasculitis, such as microscopic polyangiitis and Wegener granulomatosis. The most common antigen target for ANCAs is myeloperoxidase (MPO), which is found in neutrophils and monocytes. We report definitive experimental animal evidence that ANCAs are pathogenic. MPO knockout (Mpo(-/-)) mice were immunized with mouse MPO. Splenocytes from these mice or from control mice were injected intravenously into recombinase-activating gene-2-deficient (Rag2(-/-)) mice, which lack functioning B lymphocytes and T lymphocytes. All mice that received splenocytes developed mild to moderate glomerular immune deposits, but only mice that received 1 x 10(8) or 5 x 10(7) anti-MPO splenocytes developed severe necrotizing and crescentic glomerulonephritis, granulomatous inflammation, and systemic necrotizing vasculitis, including necrotizing arteritis and hemorrhagic pulmonary capillaritis. To test the pathogenic potential of antibodies alone, purified anti-MPO IgG or control IgG was injected intravenously into Rag2(-/-) mice and wild-type mice. Mice that received anti-MPO IgG but not mice that received control IgG developed focal necrotizing and crescentic glomerulonephritis with a paucity of glomerular Ig deposition. Thus, anti-MPO IgG alone was able to cause pauci-immune glomerular necrosis and crescent formation in the absence of functional T or B lymphocytes in Rag2(-/-) mice and in the presence of an intact immune system in wild-type C57BL/6J mice. This animal model offers strong support for a direct pathogenic role for ANCA IgG in human glomerulonephritis and vasculitis.

Adoptive Transfer↗

PubMed2002

Understanding the pathogenesis of ANCA: where are we today?

The role of ANCA, ANCA antigens, endothelial cell damage, genetic and environmental pressures, and the "activatability" of leukocytes will probably prove to be important variables in human ANCA vasculitis. The advent of a reliable animal model may open new areas of investigation and treatment of these vasculitic conditions.

Animals↗

PubMed2002

A trend analysis of organ transplantation among ethnic groups.

PURPOSE: This research provides public policy implications regarding organ resource allocation and increases public awareness of the current status of transplant use in various ethnic populations. PROCEDURES: Healthcare Cost and Utilization Project (HCUP), National Inpatient Sample (NIS) data were used to obtain a yearly estimate of the number of organ transplants by organ and by ethnic origin for 1988-1997. ICD-9-CM codes identified lung, heart, liver, and kidney organ-transplantation procedures. Each record in the sample was weighted by its respective discharge weight in order to extrapolate a national estimate. To assess whether there are significant differences among ethnic groups in organ transplantation rates over time, regression models were estimated for heart, liver, and kidney transplants. Transplantation rates were modeled as a function of time, ethnic origin, and interaction variables. FINDINGS: Examination of time trend graphs and regression analyses indicates that transplantation rates have not varied substantially across ethnic groups between 1988 and 1997. Rates for all groups, with the exception of Asians, exhibited similar time trends with little systematic variation. CONCLUSIONS: Further research is needed to determine whether variations exist due to organ availability versus prevalence of the disease.

Ethnicity↗

PubMed2002

Tissue tropism of the TTV in experimentally infected rhesus monkeys.

OBJECTIVE: To determine whether the transfusion-transmitted virus (TTV) is hepatotropic. METHODS: Total DNA was extracted from various tissues of 5 experimentally infected Rhesus monkeys during the viremic period. A dot hybridization was done with viral double stranded DNA probes or single antisense probes. RESULTS: The double-stranded probe was hybridized with DNA from the liver, bone marrow, spleen,stomach, small intestine and colon. The single-stranded antisense probe was hybridized with DNA from the liver, small intestine and bone marrow of all 5 monkeys, but not with that from other tissues. CONCLUSIONS: As the viral genome was of negative polarity, the plus-stranded fragment identified in our study might be a replicative intermediate, and was only demonstrated in the liver, small intestine, and bone marrow by dot blot hybridization with single-stranded antisense probes. It is suggested that the TTV replicates in the liver, bone marrow and small intestine, and TTV might be hepatotropic.

Animals↗

PubMed2002

Sequence analysis of Orientia tsutsugamushi DNA from mites collected in the Xisa archipelago, China.

The genotype of Orientia tsutsugamushi DNA from mites in the Xisa archipelago of China were identified. A natural focus of tsutsugamushi disease in the archipelago was found. The DNA sequence that codes for the 56 kDa protein of O. tsutsugamushi was amplified by nested polymerase chain reaction (N-PCR). The purified positive products were cloned into a pGEM-T vector and sequenced. The DNA sequence was compared with various sequences on the internet for sequence homology. A 507 bp DNA fragment encoding the 56 kDa protein was amplified from the samples. The sequence homology was 85% (Karp strain), 68% (Gilliam strain), 65% (Kato strain), and 67% (Yonchon strain). Orientia tsutsugamushi is carried by the mites of the Xisa archipelago; the main genotype is the Karp strain.

Animals↗