Biomedical subjects

Y Yan

Publications and source records attributed to Y Yan.

At least 163 records · Page 9Linked to original sources

PubMed1999

[Analysis on the epidemic characterization and trend of AIDS in Fujian Province].

OBJECTIVE: To analysed the epidemic characterization and trend of AIDS in Fujian Province based on data obtained from HIV sero-survallance, HIV-1 subtyping and epidemiological survey. METHODS: Serum samples collected from people in high risk groups and specific subgroups were examined for antibody against human immunodeficiency virus (HIV). Epidemiological investigation was conducted toward people who were sero-positive. Clinical data on patients with AIDS were also collected. Peripheral blood mononuclear cells (PBMCs) obtained from HIV-1 infectious and patients with AIDS were used for DNA amplification between C2-V3 region by PCR. The amplified products were sequenced to identify HIV-1 subtypes. RESULTS: From January 1987 through the end of December 1997, a total number of 569,873 serum samples from high risk groups and specific subgroups including blood donors and people that travelling abroad frequently were examined for HIV antibody Seventy people with HIV-1 sero-positive were identified, accounting for 0.12/1000 of the total detected numbers. Among them, 21 patients with AIDS in which 18 cases had died. HIV/AIDS cases were mainly distributed along the coastal cities as Fuzhou, Quanzhou and Xiamen where economic development was growing rapidly. Most cases were infected abroad and spreading HIV to the country through sexual transmission. Clinical data showed that early syndromes and reversal fever of patients with AIDS were seen but survival time was short. Nucleotide sequencing showed that HIV-1 strains in the province were most subtype E. CONCLUSION: HIV epidemic in the province will mainly be spreading among people with sexually promiscuous behaviors.

Acquired Immunodeficiency Syndrome↗

PubMed1999

In vitro study of the effects of endothelin-1 on human dental pulp cells.

OBJECTIVE: To study the effect of Endothelin-1 (ET-1) on cell proliferation in primary cultures of human dental pulp cells; the cell mechanism of mitogen; and collagen synthesis. METHODS: Primary cultures of human dental pulp cells; Thiazolyl Blue Tetrazolium Bromide (MTT) test to investigate cell proliferation; measurement of calcium ions in human dental pulp cells with the calcium-sensitive dye fluo-3; enzyme-linked immunosorbent assay and avidin-biotin complex immunocytochemical assay for collagen synthesis in human dental pulp cells. RESULTS: Incubation of cultures with ET-1 resulted in a dose-dependent increase in cell proliferation over control (unstimulated) cultures. In addition ET-1 increased the Ca2+ concentration in human dental pulp cells, which cannot be inhabited by Verapamil. The finding demonstrated that collagen type I synthesis of human dental pulp cells was increased by ET-1. CONCLUSIONS: ET-1 played a crucial role in pulp restoration of lesions and had an effect on mitogen and differentiation of human dental pulp cells.

Cell Division↗

PubMed1999

[The relationship of serum hepatitis B virus DNA load in HBsAg positive pregnant women to the intrauterine infection of newborns].

OBJECTIVE: To study the relationship of serum hepatitis B virus (HBV) DNA load in HBsAg positive pregnant women to intrauterine infection of their newborns. METHODS: Serum HBV DNA were determined by dot-blot hybridization in 185 HBsAg positive pregnant women. Serum HBsAg were tested by ELISA in their newborns within 24 hours after birth. RESULTS: The prevalence of intrauterine HBV infection of the newborns was associated with the HBV DNA level of the mothers. With the increase of serum HBV DNA load, the risk of fetal intrauterine infection was increasing. CONCLUSION: Fetal exposure to high level of maternal HBV DNA is one of the important determinant of intrauterine infection.

DNA, Viral↗

PubMed1999

[Anatomical basis for the newly developed facelifting].

OBJECTIVE: To investigate the relationship between the SMAS and the facial nerve divisions in the cheek area. METHOD: We dissected 12 cadaver heads(24 sides). RESULTS: 1. SMAS distributed over the middle face. It became thinner as it extended forward and there was a small aperture lateral to the mouth. The branches of facial nerve lay directly beneath the parotidomassetric fascia after emerging from the parotid gland. 2. The frontal branch penetrated the deep fascia to the SMAS at about 0.5 cm below the zygomatic arch. 3. Some buccal branches went through the cheek fat pad while the others lay on its surface directly under the thin SMAS. 4. There was constantly a zygomatic ramus went into the upper one third of the zygomaticus. It innervated the lower and lateral orbicularis oculi muscle in 9 of 24 sides (37.5%) of the cadaver heads, zygomaticus major and minor and orbicularis oculi muscle in 8 of 24 sides (33.3%), and the zygomaticus major and minor in 7 of 24 sides (29.2%). CONCLUSION: During facelifting, wide dissection of the SMAS should be done directly above the parotidomassetric fascia and 0.5 cm below the zygomatic arch. While approaching the middle face, the dissection should be limited to the lower two third of the zygomaticus, followed by elevating the zygomatic fat. The authors dissect the nasolabial fold through the lower eyelid incision, then the dissection should go downwards, under the orbicularis oculi muscle, to the nasolabial area. In a clinical situation, care must be taken not to damage the facial nerve trunk, and dissection of the upper one third of the zygomaticus should be avoided.

Adult↗

PubMed1999

[The distribution of the frontal branch of the facial nerve and its significance in facelift].

OBJECTIVE: To further understand the distribution and course of the frontal branch of the facial nerve in the temporal and zygomatic areas. METHODS: Facial dissection was performed on 9 cadaver heads(18 sides). RESULTS: It was found that the frontal of the facial nerve had 3 to 7 divisions (average 5) instead of one. The divisions of the frontal branch showed no constant course and distributed nearly all over the zygomatic arch. We divided the zygomatic arch into 3 equal parts and found that the middle third had the highest density of the branch distribution, accounting for 44.44% of the total divisions; the anterior third and the lateral third possessed 38.89% and 16.66% of the total divisions respectively. These divisions entered deeply into the temporoparietal fascia(the superficial temporal fascia). The divisions in the anterior third of the zygomatic arch innervate the lower and lateral orbicularis oculi muscle; the divisions in the middle third innervate the lateral orbicularis oculi muscle and the frontal muscle; the divisions in the lateral third innervate the frontal muscle and the anterior auricularis. CONCLUSION: We recommend discriminating the layers of the soft tissue over the zygomatic arch, not limiting the dissection range of the zygomatic arch to avoid damaging the nerve divisions while doing subperiosteal dissection of the zygomatic arch in facelifting.

Adult↗

PubMed1999

[The role of placenta in hepatitis B virus intrauterine transmission].

OBJECTIVES: To determine the role of placenta in hepatitis B virus (HBV) intrauterine transmission, and to trace the route of transplacental transmission and the timing of HBV infection in uterus. METHODS: We collected 101 term placentas and newborn infants, 24 aborted first-trimester placentas, and 6 induced aborted fetuses and placentas from 131 HBsAg carrying pregnant women. Serologic HBV markers (HBsAg and HBV DNA) of pregnant women and newborns were detected by ELISA and PCR. The HBsAg, HBxAg, HBcAg and HBV DNA in placentas were determined by ABC immunohistochemical staining and in-situ hybridization. RESULTS: The HBV infection rates of placentas from first-trimester, second-trimester to term periods were 4.2%(1/24), 1/6, and 44.6%(45/101), respectively. In one induced aborted fetal liver tissue (19-week of pregnancy), the proteins and DNA of HBV were detected, and its placental villous capillary endothelial cells were also infected. The OR of HBV infection of villous capillary endothelial cells in intrauterine transmission was 18.46(95% CI = 2.83-152.78). CONCLUSIONS: HBV infection of placental capillary endothelial cell is a major risk factor of intrauterine transmission. HBV transplacental transmission route may be placental cell to cell transfer. The intrauterine infection may occur as early as on the 19th week of pregnancy, but the main timing is possibly in the third-trimester of pregnancy.

Endothelium, Vascular↗

PubMed1999

[The architecture of the cutaneous blood vessels in scent pigs].

OBJECTIVE: To study the anatomy of cutaneous blood vessels of the scent pig, and to provide an animal model for research in plastic surgery. METHODS: Seven Chinese mini-pigs (scent pigs) were used in the study. RESULTS: 1. The scent pig is small, easy to house, rich in panniculus adiposus. 2. The origin of cutaneous blood vessels is divided into three types: the musculo-cutaneous perforator, the intermuscular septal perforator and the direct cutaneous vessel. There are some differences in distribution, size, and architecture from the characteristics of that of human being. 3. The architecture of cutaneous vessels could be divided into four vascular plexuses: the profound vascular plexus, middle vascular plexus, superficial vascular plexus of the superficial fascia and the subdermal vascular plexus. 4. The density of vessels and vessel plexuses in the neck and trunk is higher than that of the legs. CONCLUSION: In terms of the morphology of cutaneous blood vessels, the scent pig is an ideal animal model for skin flap study.

Animals↗

PubMed1999

[Re-assessment of the inframammary crease ligament].

OBJECTIVE: An anatomical study was carried out to examine the existence of the inframammary crease ligament. METHODS: 18 breasts of preserved female cadavers were dissected and dyed for the fascia. RESULTS: The so-called inframammary crease ligament described by other authors does not exist. CONCLUSION: The reinforced Cooper's ligament supports the inframammary fold in position.

Adult↗

PubMed1999

[A study of innervation of musculus temporalis and its clinical application].

OBJECTIVE: To study the innervation of the musculus temporalis and improve the successful rate of the operation for paralytic eyelid ectropion. METHODS: Anatomic dissection was performed in 12 fresh cadavers. RESULTS: The data show that the distance between the outer canthus and the crus helicis is 8.733 +/- 1.311 cm. The deep temporal nerve spread radially to the edge of musculus temporalis at 3.852 +/- 0.353 cm and 6.317 +/- 0.330 cm at a 60-degree angle to the horizontal line. The rami of the deep temporal nerve rise at a 60-degree angle to the horizontal line in 3 parts from the outer canthus to the crus helicis. CONCLUSION: In transferring the temporal muscle to treat paralytic ectropion, it is safe to make incisions at the middle one-third between the outer canthus and the crus helicis. The discovery has been used to treat 32 patients with eyelid ectropion of facial palsy, among whom 30(93.8%) got good results.

Adolescent↗

PubMed1999

[A molecular epidemiology study on risk factors and mechanism of HBV intrauterine transmission].

OBJECTIVE: To clarify the risk factors and mechanism of HBV intrauterine infection by molecular epidemiology method. METHODS: We performed a case-control study. 402 HBsAg-positive pregnant women and their infants were collected as subjects. 15 infants infected by HBV intrauterine transmission were selected as case group and others as controls. Besides, HBsAg titer in 182 maternal sera and HBV DNA concentration in 185 maternal sera were determined. To identify the HBV infection in the placentas, immunohistochemistry stain and HBV DNA hybridization in situ were conducted. The data from both laboratory and epidemiological fields were analysed. RESULTS: The findings indicated that the positiveness of HBeAg in mother's sera (OR = 17.07) and the history of threatened premature labour (OR = 5.44) were the main risk factors. Intrauterine transmission was significantly related to HBsAg titers and HBV DNA concentration in mother's sera (P = 0.01). The results of immunochemistry stain and HBV DNA situ in hybridization in the placentas from 101 full-term pregnancy women showed that HBV infection rates had a decreasing trend (P = 0.0009) from mother's side to fetus's in placenta and there was a significant association between HBV intrauterine transmission and HBV infection in villous capillary endothelial cells in placenta (OR = 18.46, P = 0.0002). CONCLUSION: There might be a "cellular transfer" of HBV infection in the placenta. With regard to the mechanism of HBV intrauterine transmission; there are two transmission routes, namely, hemagenous route and cellular route.

Adult↗

PubMed1999

[Relative analysis of the mRNA expression between endothelin and inducible nitric oxide synthase in pulpitis].

OBJECTIVE: To study the relationship between endothelin-1(ET-1) and inducible nitric oxide synthase (iNOS) through the mRNA expression in pulpitis. METHODS: The model of experimental rat pulpitis; extraction of RNA, the reverse-polymerase chain reaction(RT-PCR) were used. RESULTS: The mRNA expression of ET-1/iNOS in pulpitis groups was higher than the control. There was relationship in the mRNA expression between ET-1 and iNOS. CONCLUSION: Pulp microcirculation was mechanized by the contraction and relaxtion of ET-1/iNOS, which could have direct effects on the pathological change. The control mechanism was due to the up-regulation of ET-1/iNOS gene in transcription level.

Animals↗

PubMed1999

[Effects of endothelin-1 on the collagen synthesis of cultured human dental pulp cells].

OBJECTIVE: To study the effects of endothelin-1(ET-1) on the collagen synthesis of cultured human dental pulp cells. METHODS: Cell cultured, enzyme linked immmun sorbent assay (ELISA), and ABC immunhistochemical staining were used in the study. RESULTS: ET-1 increased the synthesis of soluble type I collagen in different periods besides the 24 h group, and had no effects on the type III collagen; immunohistochemical staining revealed that ET-1 also increased the synthesis of unsoluble type I collagen. CONCLUSION: ET-1 can stimulate type I collagenic synthesis of human dental pulp cells and might have an effect on pulp self-restoration.

Ascorbic Acid↗

PubMed1999

[A study of p53 gene mutations in squamous cell carcinoma in eyes].

OBJECTIVE: To inquire into the molecular biological mechanisms of the occurrence of squamous cell carcinoma in eyes. METHODS: Using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method, we detected 63 samples taken from 63 cases (including 36 invasive squamous carcinoma, 7 carcinoma in situ, 20 papillomas) for 248 point mutations in p53 gene. RESULTS: 22.2% (8/36) squamous cell carcinomas, 14.3% (1/7) carcinomas in situ were shown to contain the point mutation in codon 248 of p53 gene exon 7 and no point mutation was found in papillomas, the difference being significant (P = 0.021). No point mutation was in patients over 70, while in patients younger than 70, the mutation rate was 33.3%, the difference being significant (P = 0.24). No significant correlation was found between p53 gene mutations and clinical pathological manifestations (P > 0.05). CONCLUSIONS: p53 gene mutations play roles in the early stage of the development of squamous cell carcinomas, and there is no correlation between p53 gene mutations and clinical manifestations. The mutation in p53 gene is not the main cause of neoplasms in the elder persons after the seventh decade of life.

Adolescent↗

PubMed1999

[Ultrastructural characteristics of epiretinal membranes].

OBJECTIVE: To investigate ultrastructural features and the correlation between the cell activation and extracellular matrix (ECM) expression of epiretinal membranes. METHODS: Immuno-electron-microscopy was done on the epiretinal membranes removed by vitrectomy from 16 patients with rhegmatogenous retinal detachment associated with proliferative vitreoretinopathy (PVR). The specimens were stained with antibodies to ECM proteins, including type I collagen, type III collagen and fibronectin (FN). RESULTS: A type of cells with a number of lamellipodia was found in membrane sections of 9 patients. The lamellipodia appeared to be either coiled or branched and were surrounded by abundant collagen fibers of type I and III. The cells with lamellipodia varied in their phenotypes and with or without pigment. There were dense gold particles of FN in contact regions of lamellipodia and collagen. CONCLUSIONS: Our observations support that the contraction of epiretinal membranes is the result of an interaction between cells and collagen, and the cells extending lamellipodia may initiate contractile events. FN is responsible for this contractile action.

Collagen Type I↗

PubMed1999

[Synthetic assessment of health impact of cerebrovascular diseases on potential health days of life lost].

OBJECTIVE: To assess synthetically the impact on population health caused by cerebrovascular diseases. METHODS: Incidence, duration of disease, disabilities and deaths of cerebrovascular diseases were analyzed with potential health days of life lost (PHDLL) as an indicator in urban areas of Changsha, Hunan Province. RESULTS: The PHDLL caused by cerebrovascular disease totaled 2 624.94 days per thousand of population, 33.01% of them attributed to deaths and 53.44% to chronic disability. CONCLUSION: Hemorrhagic cerebrovascular disease mainly lead to death and ischemic one caused chronic disability.

Adolescent↗

PubMed1999

[Research on quality of life of stroke patients and linear model of its impact factors].

The present study reviewed the investigation of 278 stroke patients of Changsha city population in 1994. The result showed that patients of stroke might have different quality of life during the process of their illness. Multiple regression model indicated that major factors on the chronic stroke patients were type of stroke, age, home nursing time, labor-losing days, occupations. The study provides reference source for prevention of stroke and improvement of quality of life.

Adult↗

PubMed1999

[Regulation of p53 and bcl-2 proteins to apoptosis and cell proliferation in liver cirrhosis and hepatocellular carcinoma].

In situ apoptosis labelling was used for detecting apoptotic cells, and immunohistochemistry for p53, bcl-2 proteins and proliferation cell nuclear antigen(PCNA) in hepatocellular carcinoma(HCC) and liver cirrhosis tissues. The results were that in HCC, the number of apoptotic cells was higher, the density of proliferation cells lower, and expressions of p53 and bcl-2 protein were stronger than that in liver cirrhosis, and they were related to differentiation degree of HCC. The data indicate that overexpression of bcl-2 and mutant p53 proteins, which causes imbalance between cell proliferation and apoptosis, may bring about genesis and development of HCC by selecting proliferation of cells.

Adult↗

PubMed1999

[Cloning and sequencing of variable region gene of heavy chain of monoclonal antibody against SA I/II of Streptococcus mutans].

OBJECTIVE: To clone and sequence a immunoglobulin variable region of heavy chain (VH) from a mouse hybridoma 2B12F6, which produce monoclonal antibody against SA I/II of Streptococcus mutans. METHODS: The immunoglobulin variable region gene of heavy chain of 2B12F6 was amplified and cloned into pUC18 by using PCR technique and gene engineering technique, and then the gene sequence was analyzed by Sanger's method. RESULTS: The VH gene segment was 360 base pairs in length and coded 118 amino acids, and the homology of framework of VH gene and mouse VH gene published was 70%, which accorded with the feature of mouse VH gene. CONCLUSION: The VH gene gained from 2B12F6 could provide the possibility of construction of gene engineering antibody against SA I/II of Streptococcus mutans.

Amino Acid Sequence↗