Biomedical subjects

Min Hu

Publications and source records attributed to Min Hu.

120 records · Page 7Linked to original sources

PubMed2002

Mutation scanning analysis of mitochondrial cytochrome c oxidase subunit 1 reveals limited gene flow among bovine lungworm subpopulations in Sweden.

A mutation scanning approach was employed to investigate the population genetic structure of the bovine lungworm, Dictyocaulus viviparus (Nematoda: Trichostrongyloidea), in southern Sweden. A total of 252 individual nematodes were collected from cattle representing 17 farms. A portion of the mitochondrial cytochrome c oxidase subunit 1 gene (pcox1) was amplified from genomic DNA isolated from individual lungworms by the polymerase chain reaction (PCR), and then subjected to single-strand conformation polymorphism (SSCP). Samples with distinct SSCP profiles were then sequenced. In total, 12 distinct pcox1 haplotypes (393 bp) were defined for the 252 individuals, and pairwise sequence differences among the haplotypes ranged from 0.3-2.3%. Average haplotype diversity and nucleotide diversity values were 0.16 and 0.002, respectively. There was no particular correlation between pcox1 haplotypes and their geographical origin. The "overall fixation" indices F(ST) and N(ST) were calculated to be 0.77 and 0.65, respectively. The results of this study revealed that both the mitochondrial DNA sequence diversity within populations and the gene flow among populations of D. viviparus were low. This is similar to findings for some parasitic nematodes of plants and insects, but distinctly different from gastrointestinal trichostrongyloid nematodes of domesticated ruminants considered to have relatively high levels of genetic diversity and gene flow. Such differences were interpreted to relate mainly to differences in host movement as well as parasite biology, population sizes and transmission patterns, and should therefore be of epidemiological relevance.*

Animals↗

PubMed2002

The mitochondrial genomes of the human hookworms, Ancylostoma duodenale and Necator americanus (Nematoda: Secernentea).

The complete mitochondrial genome sequences were determined for two species of human hookworms, Ancylostoma duodenale (13,721 bp) and Necator americanus (13,604 bp). The circular hookworm genomes are amongst the smallest reported to date for any metazoan organism. Their relatively small size relates mainly to a reduced length in the AT-rich region. Both hookworm genomes encode 12 protein, two ribosomal RNA and 22 transfer RNA genes, but lack the ATP synthetase subunit 8 gene, which is consistent with three other species of Secernentea studied to date. All genes are transcribed in the same direction and have a nucleotide composition high in A and T, but low in G and C. The AT bias had a significant effect on both the codon usage pattern and amino acid composition of proteins. For both hookworm species, genes were arranged in the same order as for Caenorhabditis elegans, except for the presence of a non-coding region between genes nad3 and nad5. In A. duodenale, this non-coding region is predicted to form a stem-and-loop structure which is not present in N. americanus. The mitochondrial genome structure for both hookworms differs from Ascaris suum only in the location of the AT-rich region, whereas there are substantial differences when compared with Onchocerca volvulus, including four gene or gene-block translocations and the positions of some transfer RNA genes and the AT-rich region. Based on genome organisation and amino acid sequence identity, A. duodenale and N. americanus were more closely related to C. elegans than to A. suum or O. volvulus (all secernentean nematodes), consistent with a previous phylogenetic study using ribosomal DNA sequence data. Determination of the complete mitochondrial genome sequences for two human hookworms (the first members of the order Strongylida ever sequenced) provides a foundation for studying the systematics, population genetics and ecology of these and other nematodes of socio-economic importance.

Amino Acid Sequence↗

PubMed2002

Diurnal variations of aerosol chemical compositions and related gaseous pollutants in Beijing and Guangzhou.

A new apparatus, Steam Jet Aerosol Collector (SJAC) combined with on-line Mobile Ion Chromatograph provides a reliable way to measure both aerosol components and related gas species simultaneously. The SJAC was applied in the field campaigns in Beijing and Guangzhou to investigate aerosol chemical compositions and related gaseous pollutants. The concentration levels and diurnal variations are discussed, which implies differences in atmospheric chemistry of gas-to-particle conversions in Beijing and Guangzhou.

Aerosols↗

PubMed2002

cAMP-activated protein kinase-independent potentiation of insulin secretion by cAMP is impaired in SUR1 null islets.

Whereas the loss of ATP-sensitive K(+) channel (K(ATP) channel) activity in human pancreatic beta-cells causes severe hypoglycemia in certain forms of hyperinsulinemic hypoglycemia, similar channel loss in sulfonylurea receptor-1 (SUR1) and Kir6.2 null mice yields a milder phenotype that is characterized by normoglycemia, unless the animals are stressed. While investigating potential compensatory mechanisms, we found that incretins, specifically glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic peptide (GIP), can increase the cAMP content of Sur1KO islets but do not potentiate glucose-stimulated insulin release. This impairment is secondary to a restriction in the ability of Sur1KO beta-cells to sense cAMP correctly. Potentiation does not appear to require cAMP-activated protein kinase (PKA) because H-89 (N-[2-(p-bromocinnamylamino)ethyl]-5-isoquinolinesulfonamide) and KT5720, inhibitors of PKA, do not affect stimulation by GLP-1, GIP, or exendin-4 in wild-type islets, although they block phosphorylation of cAMP-response element-binding protein. The impaired incretin response in Sur1KO islets is specific; the stimulation of insulin release by other modulators, including mastoparan and activators of protein kinase C, is conserved. The results suggest that the defect responsible for the loss of cAMP-induced potentiation of insulin secretion is PKA independent. We hypothesize that a reduced release of insulin in response to incretins may contribute to the unexpected normoglycemic phenotype of Sur1KO mice versus the pronounced hypoglycemia seen in neonates with loss of K(ATP) channel activity.

ATP-Binding Cassette Transporters↗

PubMed2002

[Oral venous lakes: a clinicopathologic analysis of 20 cases].

OBJECTIVE: To improve the recognization and treatment for oral venous lakes (OVL). METHODS: Clinicopathologically analysis of 20 cases of oral venous lakes was performed. All the samples were removed by surgically. RESULTS: All the lesions occurred in senile persons and located under the mucosa. Among the 20 cases, 11 were male patients and 9 were female; 18 of 20 occurred in the lower lip, another two in the upper lip and buccal mucosa. The lesions were 0.3 approximately 1.2 cm in size. Pathologically, the oral venous lake was composed of single or a few large, dilated and irregular veins. Thrombosis and organization were found within the lesions sometimes. CONCLUSIONS: Oral venous lakes are a kind of focal anomalies of venous structure. All the 20 cases (with a follow-up time from 8 months to 4 years) has no recurrence after surgical treatment.

Aged↗

PubMed2002

[Effects on fine particles by the continued high temperature weather in Beijing].

The continued high temperature weather (CHTW) appeared in Beijing since June 23 1999. The measurements showed the PM2.5 mass concentrations were 2 to 3 times of that in non-CHTW period. However the diffusion conditions were still fine in these days. Both the highest hourly concentrations of O3 and the SO4(2-) composition in PM2.5 can identify that the photochemical action was very active. It is the very reason to produce more fine particles in atmosphere.

Air Pollutants↗

PubMed2002

The effects of local administration of Zoledronate solution on the tooth movement and periodontal ligament.

OBJECTIVE: To investigate the effects of local administration of Zoledronate solution on the tooth movement and periodontal ligament. METHODS: Orthodontic tooth movement of upper first molar was performed in 42 rats with coil spring. Zoledronate solution was injected into the palatal submucosal area adjacent to the left upper first molar in experimental group 3 days prior to the use of the appliance. In control group, same amount of 0.9% NaCl solution was injected into the palatal submucosal area adjacent to the left and right upper first molar. The injection was applied every third day. The application of mesial force lasted 0.3, 7, 14, 21 days respectively. After the rats were sacrificed, the distance of tooth movement was measured. Sections were stained and then observed with microscope. RESULTS: 1. The distance of tooth movement in the experimental group was significantly smaller than that in the control group. 2. The number of osteoclast on the pressure side in the experiment group was significantly smaller than that in the control group through the experimental period, but there was no distinct difference between experimental group and control group (except for 14 days) for the number of odontoclast in interradicular area. 3. The osteoclasts and odontoclasts were the main target cell of Zoledronate in periodontal tissue. CONCLUSIONS: Zoledronate may be a useful agent for anchorage control and reducing the number of osteoclast on pressure side of alveolar bone.

Animals↗

PubMed2002

Effects of repeated + Gz forces on masticatory muscles.

OBJECTIVE: To study the effects of repeated + Gz forces on masticatory muscles. METHODS: 48 male Wistar rats were randomly divided into 4 groups. Group A was normally fed. Group B was only fixed with rat-kept devices for 5 minutes. Group C was borne + 1 Gz for 5 minutes. Group D was repeatedly exposed + 10 Gz (each for 30 s, onset rate about 0.5 G/s, 5 times/d with + 1 Gz 1 minute intervals, 4 d/wk, 3 weeks in total). The histological changes of the masseter, temporal and lateral pterygoid muscles were observed. RESULTS: No abnormal changes were observed in Group A, B and C. But pathological changes could be found in group D. The wrench and deformation of muscular fibers, the dissolution of partial myofibril, the swelling of mitochondria, the reduce of hepatin from the masseter and lateral pterygoid muscles could be found. CONCLUSIONS: Repeated + Gz stresses could induce the damage of masticatory muscles in different degrees.

Animals↗

PubMed2002

[Source apportionment on fine particles in Beijing].

The positive matrix factorization(PMF) method was used to apportion the sources for fine particles in Beijing. The data were obtained from four samplings from 1999 to 2000. The number of this data set was 40. The chemical compositions used in analysis include element carbon(EC), organics, SO4(2-), F-, Cl-, Fe, Ca, K, Mg, Al, Na, Zn, Mn, Ti, Pb, Ba and P. Six main sources, soil dust, construction dust, secondary source (by photochemical action), biomass burning, motor vehicle and coal burning were found.

Air Pollutants↗

PubMed2000

Composite mandibular allografts in canines.

OBJECTIVE: To evaluate the feasibility of transplanting composite mandibular allografts to repair large mandibular defects. METHODS: Three composite mandibular trans-plantation models were established. The first model consisted of hemimandible with the attached teeth, muscle and skin,and oral mucosa. The second model was transplanted in the same way with the first one excluding oral mucosa and some teeth, and third one excluding the oral mucosa and all dental crowns. Fourteen transplanting operations were performed in canines. Cyclosporine A and methylprednisone were given for immunosuppression. RESULTS: The composite mandibular organs had an effective and closed return circuit. Transplantation of vascularized allograft of mandibular compound organs was feasible. Two longest time survivors of 67 d and 76 d were in the third model group. Cyclosporine A was successful in suppressing rejection of transplanted composite allograft and prolonging survival time of transplantation models. CONCLUSIONS: The composite mandibular allografts were available with large block of living composite tissue, and helpful in restoration of appearance and function for severe mandibular defects.

Journal Article↗

PubMed1998

Expression and significance of HBV genes and their antigens in human primary intrahepatic cholangiocarcinoma.

AIM:To explore the etiology and pathogenesis of human primary intrahepatic cholangiocarcinoma, the expression of HBV genes and HBV-antigens was detected in the cancerous tissue and its surrounding hepatic tissues.METHODS:HBV-antigens were detected by immunohistochemical technique and HBV genes were examined with in situ hybridization.RESULTS:In 20 cases of cholangiocarcinoma, the positive detection rate of HBxAg, pre-S1, pre-S2, HBsAg and HBcAg was 75%, 40%, 40%, 10% and 0%, respectively, and in the surrounding hepatic tissues of 19 cases the positive rates were 84.2%, 47.9%, 47.9%, 31.6% and 31.6%.Among 40 cases of cholangiocarcinoma, the positive rate of HBV-DNA, x-gene, pre-s gene, s gene and s gene fell on 77.5%, 70.0%, 47.5%, 40% and 42.5%, respectively,and of the surrounding hepatic tissues in 33 cases, 87.9%, 84.8%, 63.6%, 69.7% and 66.7%.CONCLUSION:The development of human primary intrahepatic cholangiocarcinoma bears a close relationship with chronic persistent HBV infection. Particularly,the x gene of HBV and its protein (HBxAg) might play an important role in pathogenesis of hepatic carcinoma.

Journal Article↗

PubMedDate not supplied

Repair of large articular cartilage defects with implants of autologous mesenchymal stem cells seeded into beta-tricalcium phosphate in a sheep model.

Tissue engineering has long been investigated to repair articular cartilage defects. Successful reports have usually involved the seeding of autologous chondrocytes into polymers. Problems arise because of the scarcity of cartilage tissue biopsy material, and because the in vitro expansion of chondrocytes is difficult; to some extent, these problems limit the clinical application of this promising method. Bone marrow-derived mesenchymal stem cells (MSCs) have been proved a potential cell source because of their in vitro proliferation ability and multilineage differentiation capacity. However, in vitro differentiation will lead to high cost and always results in decreased cell viability. In this study we seeded culture-expanded autologous MSCs into bioceramic scaffold-beta-tricalcium phosphate (beta-TCP) in an attempt to repair articular cartilage defects (8 mm in diameter and 4 mm in depth) in a sheep model. Twenty-four weeks later, the defects were resurfaced with hyaline-like tissue and an ideal interface between the engineered cartilage, the adjacent normal cartilage, and the underlying bone was observed. From 12 to 24 weeks postimplantation, modification of neocartilage was obvious in the rearrangement of surface cartilage and the increase in glycosaminoglycan level. These findings suggest that it is feasible to repair articular cartilage defects with implants generated by seeding autologous MSCs, without in vitro differentiation, into beta-TCP. This approach provides great potential for clinical applications.

Animals↗