Biomedical subjects

L Wang

Publications and source records attributed to L Wang.

At least 595 records · Page 33Linked to original sources

PubMed2001

[The survey of HIV prevalence among children between 0 to 7 years old in one county in China].

OBJECTIVE: To estimate the HIV prevalence among children between 0 to 7 years old in one county with HIV epidemic. METHODS: In September 2000, finger tip blood samples were collected from 619 children between 0 to 7 years old in three districts of one county with high HIV prevalence and tested for HIV antibody and HBV antigen. RESULTS: Among those 619 children, 11 were found HIV positive, with the prevalence of 1.8% (11/169). The HIV prevalence of three districts were 5.9% (10/169), 0.5% (1/206), and 0% (0/244), respectively. The possible channel associated with the HIV infection was mother-to-child transmission since none of the infected children had the history of blood transfusion. Twenty-four tested children were found HBV positive and the prevalence was 4.3 (24/619). CONCLUSION: There was higher HIV prevalence in children between 0 to 7 years old in certain areas. More intervenes are needed in the future to prevent the HIV spreading through mother-to-child transmission.

Child↗

PubMed2001

[The study of countermeasures on measles control in infants].

OBJECTIVE: To understand: a) measles antibody levels in purpura and their newborns, and the relation between them, b) maternal transferred measles antibody level of different age group infants, c) immunization rates of success in 6 and 8 month old infants, d) to study measles control countermeasures on infants. METHOD: To test measles IgG antibody levels of infant's blood using ELISA method. RESULTS: Antibody levels of measles in 58 pairs of mother and their newborns, 51 pairs were the same, while 7 pairs were different. Measles antibody levels in newborns was not high and reduced to 50% in 3 months, 20% in 6 months, and 15% in 8 months. The antibody levels in 6 and 8 month olds were low, nearly no protection to children. It was found that rates of immunization success and the antibody distribution were not statistically different between 6 and 8 months olds after measles vaccination. CONCLUSION: It was found that the measles antibody level in most matured women was low. Since mother's measles antibody level has close relation to their newborns, it seems that the newborn's antibody level can be improved by vaccination to matured women. In order to reduce morbidity of infant measles, the age of first vaccination of measles vaccine should be changed from 8 months old to 6 months old in some regions.

Age Factors↗

PubMed2001

[Studies on the spatial and familial aggregation of double Y nuclear family in gastric cancer pedigree].

OBJECTIVE: To explore whether there existed spatial and familial aggregation in gastric cancer in Yangzhong City of Jiangsu Province. METHODS: Using the data collected from cancer incidence registry and report system in Yangzhong City and newly designed investigation for double Y nuclear family, a genetic epidemiological study was conducted in 448 nuclear pedigrees with gastric cancer and 437 control pedigrees, involving 5 242 family members. RESULTS: Chi square test of goodness-of-fit for Poisson distribution showed there was difference between real incidence rate of gastric cancer in all townships and towns in Yangzhong and expected distribution, with chi(2) = 191.07, P < 0.001. The highest rate was in Sanyao, Changhong and Youfang townships, which was 2.2 times higher as that in the areas with low-incidence rate. Prevalence rate of gastric cancer was significantly higher in the siblings (5.42%) and parents (8.65%) of the probands, than that in siblings and parents of their spouses (4.94% and 3.20%, respectively). Prevalence rate of gastric cancer in the offspring with both parents suffered from gastric cancer was the highest, 22.58%. Test for goodness-of-fit of binominal distribution showed that there was significant difference between observed number and expected number of pedigrees with gastric cancer, with P < 0.0001. CONCLUSION: There was not only significantly spatial aggregation of gastric cancer in Yangzhong City, but also familial aggregation, which coincided with a mode of multi-genetic inheritance based on preliminary results and laid a foundation for exploring the difference in gentic susceptibilities and environmental factors for gastric cancer in Yangzhong City.

China↗

PubMed2001

[Clinical and MRI diagnosis of nasopharyngeal carcinoma with orbital spread].

OBJECTIVE: To study the routes, clinical manifestations and MRI characteristics of nasopharyngeal carcinoma (NPC) with orbital spread. METHODS: Twenty (23 eyes) such cases were selected, including 6 (7 eyes) preradiotherapy cases and 14 (16 eyes) postradiotherapy cases. The magnetic resonance imaging (MRI) axial, coronal, sagittal routine procedures and gadolinium-diethylene triamine pentaacetic acid (GD-DTPA) contrast-enhanced scan were performed. Fatty-restraint scan was performed after enhancement only on 3 cases. The diagnosis in all the patients was proved by the biopsy from the nasopharynx. RESULTS: (1) Single orbit involvement was seen in 17 patients, 12 in the left and 5 in the right orbit. Bilateral orbit involvement was only found in 3 patients. (2) Major clinical manifestations of orbital involvement by NPC included: 13 cases (15 eyes) suffered from decrease of visual acuity, 9 cases (10 eyes) with exophthalmos, 11 patients (12 eyes) with ocular movement disorder, 7 cases (9 eyes) with diplopia and 5 cases (7 eyes) with blepharoptosis. (3) MRI appearances: There were 13 cases (15 eyes) with optic nerve involvement, 9 patients (11 eyes) with abnormalities in extraocular muscle, 8 cases (9 eyes) with retrobulbar tumor and 15 cases (17eyes) with orbital apex and orbital lamina bony involvement. (4) The three main routes for orbital involvement in NPC patients were as follows: (a) through cavernous sinus (the skull base) to superior orbital fissure. (b) through paranasal sinus (particularly the ethmoid sinus). (c) through pterygopalatine fossa to inferior orbital fissure. CONCLUSION: MR imaging is very useful to demonstrate the presence, location and extent of orbital involvement in NPC patients.

Adult↗

PubMed2001

[A clinicopathological study of clear cell sarcoma of the kidney].

OBJECTIVE: To study the clinicopathological, immunohistochemical features and the histogenesis of clear cell sarcoma of the kidney (CCSK). METHODS: CCSK specimens from 45 pediatric cases, including 31 male and 14 female with an age range from 3 months to 12 years (mean of 3.2 years), were retrieved. Routine pathological, immunohistochemical and electron microscopic methods were utilized to analyze the CCSK specimens. RESULTS: 35 of the 45 cases were followed from 6 to 192 months. 15 patients presented with bone metastases, 6 had lung or liver metastases, 8 recurred and 20 died. Age and clinical stage at diagnosis correlated with the rate of survival. Histologically, the classic pattern of CCSK consisted of cells with pale cytoplasm, fine nuclear chromatin and indistinct nucleoli separated by an arborizing fibrovascular stroma. Other patterns were identified, including myxoid, spindle, palisading, epithelioid, sclerosing, cellular, cystic, and angiectatic. All tumors contained multiple patterns. Immunohistochemically, all cases were positive for vimentin, but negative for EMA, CK, desmin, actin, S-100, NSE, CD99, CD34 and LCA. Electron microscopy of 9 cases showed features of primitive cell conjunction and few organelles. CONCLUSION: CCSK is a common renal neoplasm of childhood. CCSK may arise from renal mesenchymal cells and has the propensity to metastasize to the bone with poor clinical outcome.

Child↗

PubMed2001

[GATA-2 gene expression in leukemia patients and its significance].

OBJECTIVE: To investigate GATA-2 gene expression in leukemia patients and its clinical significance. METHODS: GATA-2 gene transcripts were detected by reverse transcriptase polymerase chain reaction (RT-PCR), and bcr/abl or PML/RAR alpha transcripts were detected in patients with chronic myeloid leukemia (CML) and acute promyelocytic leukemia (APL), respectively. RESULTS: The GATA-2 transcripts were revealed in 93% of acute myeloid leukemia (AML), in 70% of acute lymphoblastic leukemia (ALL), and 83% of CML patients, but not in normal bone marrow and peripheral blood cells. GATA-2 expression in remission patients was similar to newly diagnosed or relapsed patients. In post-transplantation patients, GATA-2 expression was significantly decreased. In these cases GATA-2 transcripts could be detected with bcr/abl fusion gene disappeared in 2 of 12 CML, whereas neither GATA-2 nor PML/RARalpha transcripts could be detected in APL. CONCLUSION: GATA-2 transcripts was highly expressed in leukemia patients and had no change in remission but significantly decreased in post-transplantation patients. Detection of GATA-2 expression would give information about the residual leukemia stem cells.

Bone Marrow Cells↗

PubMed2001

[Study on new techniques for genetic diagnosis of deletional alpha-thalassemia].

OBJECTIVE: To develop polymerase chain reaction (PCR) techniques for diagnosis of three commonest deletional alpha-thalassemia determinants in China: - -(SA), - alpha(3.7) and - alpha(4.2). METHOD: Three groups of primers were designed and used to amplify the respective type of the deletional alpha-thalassemia under an optimized PCR condition, followed by agarose gel electrophoresis and EB-stainning. RESULT: Homozygous and heterozygotes, as well as double heterozygous of the 3 commonest deletions were successfully detected and diagnosed by the developed techniques. The results were identical to that from Southern Blot analysis. Forty two cases of alpha-thalassemia were diagnosed by these techniques. CONCLUSION: The 3 PCR-based techniques established by our lab were accurate, simple, and well reproducible for gene diagnosis of the deletional alpha-thalassemia determinants.

DNA Primers↗

PubMed2001

Tensile strength of human dentin as a function of tubule orientation and density.

PURPOSE: This study investigated the ultimate tensile strength (UTS) of human dentin as a function of tubule orientation and density. MATERIALS AND METHODS: Slabs of dentin (ca 0.7 mm thick) were obtained from human third molars by either transversally or longitudinally sectioning the crowns with an Isomet saw. The slabs were gently trimmed to reduce the central area of the coronal dentin to a cross-sectional area of approximately 0.5 mm2. The longitudinally sectioned slabs were either trimmed from the mesial and distal sides or from the occlusal and pulpal aspects to permit the tensile load to be applied either parallel or perpendicular to the tubule orientation. The transversally sectioned specimens were obtained at several distances from the pulp and were used to evaluate the effects of tubule density. The trimmed specimens were tested in tension on a Kratos testing machine at 0.5 mm/min. After failure, the UTS of each was calculated and expressed in MPa. The fractured ends of the transversally sectioned specimens were viewed under SEM to calculate the number of tubules per mm2 at the site of fracture, and its relation with the UTS was investigated by regression analysis. RESULTS: The UTS of dentin is higher when the load is applied perpendicular to the tubule orientation (80 +/- 13 MPa) than when applied parallel to tubule orientation (58 +/- 11 MPa, p < 0.05). There was a tendency for dentin to be weaker as the number of tubules at the site of fracture increased, although this relationship was not statistically significant (R2 = 0.051, p > 0.05). CONCLUSION: The UTS of dentin is dependent on the tubule direction. Dentin tends to be weaker as the number of tubules per area increases.

Dental Stress Analysis↗

PubMed2001

[The biochemical properties of L-arginine/nitric oxide pathway in rat brain mitochondria].

Biochemical property of L-arginine (L-Arg)/nitric oxide synthase (NOS)/nitric oxide (NO) system was observed in rat brain mitochondria. The results showed that there existed L-Arg transporters of high-affinity, low-transport and saturability in mitochondria membrane of normal rat brain. The maximum transport velocity (V(max)) and Michaelis constant (Km) were 5.87+/ -0.46 nmol/mg pro x min(-1) and 7.8+/- 0.56 micromol/L respectively. In normal condition, endothelium-type NOS was expressed in the mitochondria of rat brain, with its V(max) and Km being 2.7+/-0.3 nmol/mg pro x min(- 1) and 20.85+/-3.27 micromol/L, respectively. NO production was increased in a time-dependent manner and reached a maximum value at 60 min. These results suggest that the L-Arg transporters in MT membrane of normal rat brain were similar with Y(+) type amino acid transporters in cellullar membrane. Furthermore the NOS of mitochondria belongs to eNOS, whereas the L-Arg/NOS/NO system may be a source of NO.

Animals↗

PubMed2001

[Study on endothelial cell injury in women with pregnancy induced hypertension].

OBJECTIVE: To investigate the mechanisms of endothelial cell injury in women with pregnancy induced hypertension (PIH). METHODS: Human umbilical endothelial cells were cultured in the serum from 10 women with severe PIH and 10 normal pregnant women, and co-cultured with neutrophils or not for 48 hrs. The morphology and cell cycles were studied. RESULTS: Without neutrophils, no apoptotic cells were observed, while neutrophils were added, apoptotic cells were obviously detected. The percentage of apoptotic cells in PIH was more than that in non-PIH. The percentage of cells in G2/M phase decreased in all the groups, but there were no significant differences among them. CONCLUSIONS: Endothelial cells were injured indirectly in PIH patients. Activated neutrophils induced apoptosis might be one of the answers.

Adult↗

PubMed2001

Polytomous modeling of cognitive errors in computer adaptive testing.

In the past two decades of psychometric research, an array of extended item response models has been proposed to capture the complex nature of human cognition. While the literature abounds in model fit analysis, the debate on model selection in different testing conditions continues. This study examines the problems of model selection in computer adaptive testing (CAT) of cognitive errors by comparing the relative measurement efficiency of polytomous modeling over dichotomous modeling under different scoring schemes and termination criteria. Monte Carlo simulation was adopted as the inquiry paradigm to generate 1000 subjects and 100 items in the calibration sample and 200 simulees in the CAT sample. The results suggest that polytomous CAT yields marginal gains over dichotomous CAT when termination criteria are more stringent (shorter test length or smaller standard error of ability estimate). When the conventional dichotomous scoring scheme is adopted, in which all partially correct answers are scored as incorrect, polytomous CAT cannot prevent the non-uniform gain in test information as was observed in paper-and-pencil testing.

Computer Simulation↗

PubMed2001

[Protective effect of Panax quinquefolium 20s-proto-panaxdiolsaponins on acute myocardial infarction in dogs].

OBJECTIVE: To study the protective effects of Panax quinquefolium 20s-protopanaxdiolsaponins extracted from leaves of P. quinquefolium (PQDS) on acute myocardial infarction(AMI) in dogs. METHOD: The parameters of myocardial infart size, the serum CK and LDH activity, myocardial metabolism, free radicals and coronary circulation etc were determined by using the model of ligation of LAD in the anaesthetized open-chest dogs. RESULT: In dogs treated with PQDS(in a dosage of 10 and 20 mg.kg-1 i.v. infusion), the myocardial infarct size, the activity of serum CK, LDH and the contents of serum FFA and LPO were decreased, whereas the activity of serum SOD and GSH-Px increased markedly. At the same time, myocardial blood flow was increased and coronary vascular resistance decreased significantly. CONCLUSION: PQDS has protective effect on myocardial ischemia by modifying metabolic dysfunction of FFA, inhibiting oxygen free radical mediated peroxidation of membrane lipids, enhancing endogenous antioxidase activity and increasing myocardial blood supply.

Animals↗

PubMed2001

[Expression of Fas and Fas ligand in lesions of patients with discoid lupus erythematosus].

OBJECTIVE: To study the relation of apoptosis and pathogenesis of lupus erythematosus. METHODS: Expressions of Fas and Fas ligand(FasL) were detected in 30 lesions of discoid lupus erythematosus(DLE) and 5 skin specimens from healthy controls by immunohistochemical staining. RESULTS: Fas and FasL were positively expressed in most epidermal keratinocytes, infiltrating lymphocytes around blood vessels and appendages, and Fas was positively expressed in a few sweat ducts and hair follicles. Fas and FasL expressions were weakly positive or negative in healthy controls. CONCLUSION: Apoptosis induced by Fas, FasL pathway may be related to the pathogenesis of lupus erythematosus.

Adult↗

PubMed2001

[A comparison between the effects of albuterol and isoproterenol in bronchodilation test].

OBJECTIVE: To compare albuterol with isoproterenol as a bronchodilator in pulmonary function test and their value in the diagnosis and differential diagnosis of asthma. METHODS: Two groups (59 patients with asthma and 37 patients with COPD) were included in this study, and the patients of each group were randomly divided into 2 subgroups. The patients in the 2 subgroups inspired the two drugs in a cross-over by odd or even days. The pulmonary functions were evaluated. RESULTS: The changing rates of pulmonary functions induced by the two drugs in the two groups were positively correlated (P < 0.005), The changing rates of FEV1, MMEF, Raw, sGaw induced by albuterol were higher than the ones induced by isoproterenol in patients with asthma(P < 0.02), however the changing rates of FVC and PEF in asthma cases and all the above parameters in COPD cases were not significantly different between the two drugs(P > 0.10). The comparison of positive case number between asthma and COPD cases induced by both drugs showed significant difference(P < 0.005); especially, when the positive rate of sGaw induced by albuterol in asthma cases reached 98%, the positive rates in COPD cases was generally much lower. CONCLUSION: Bronchodilation test is a valuable diagnostic method for asthma. In this study, albuterol was superior to isoproterenol. The most sensitive index in bronchodilation test was sGaw, then in order, FEV1(92%), MMEF and Raw; the FVC and PEF were relatively insensitive.

Adult↗

PubMed2001

[Mitochondrial DNA mutations in matrilineal nonsyndromic deafness pedigrees of southwest China].

OBJECTIVE: To identify the incidence of the 1555A-->G mutation and explore the audiological features of pedigrees with matrilineal non-syndromic deafness in Southwest of China so as to provide the theoretical evidence for establishing the method of gene diagnosis. METHODS: Six pedigrees with 102 members were evaluated audiologically and clinically. DNA was extracted from their blood samples. All subjects were screened for mitochondrial DNA 1555A-->G mutation by Alw 26I restriction endonuclease digestion. RESULTS: Seventeen maternal relatives of aminoglycoside antibiotic induced deafness (AAID) pedigree 1 and pedigree 2, carried 1555A-->G mutation. 10 maternal relatives of Non-AAID pedigree 6 also carried 1555A-->G mutation. No mutation was found among paternal relatives and pedigrees 3, 4 and 5. CONCLUSION: The same audiological features of these pedigrees are: bilateral and symmetrical progressive sensorineural hearing loss with variable age of onset. The 1555A-->G mitochondrial mutation is one of the hereditary factors for this disorder. 4 Aminoglycoside antibiotic plays an important role in developing deafness. The incidence of the 1555A-->G mutation in AAID and matrilineal non-syndromic deafness pedigrees is fairly high. Screening for mitochondrial 1555A-->G mutation may be of great clinical use fullness.

Aminoglycosides↗

PubMed2001

[Cell proliferation in odontogenic jaw cyst epithelium].

OBJECTIVE: The aim of the study is to investigate the epithelial cell proliferation in the lining of odontogenic cysts with Ki-67 monoclonal antibody. METHODS: Ki-67 expression was studied in 30 odontogenic cysts (odontogenic keratocysts, n = 10; dentigerous cyst, n = 10; radicular cysts, n = 10), and normal oral epithelium (n = 10) by using a biotin streptavidin method on routinely processed paraffin sections after microwave treatment. Ki-67+ cells were counted manually and related to the area of epithelial lining as determined by computer image analyzer. The result was analyzed by using a computer image analyzer to calculate positive cells per square millimeter of the epithelial lining of odontogenic lesions. Data were analyzed by using student test. RESULTS: The epithelial lining of odontogenic keratocysts contained the highest number of Ki-67+ cells, most of which were located in the suprabasal layers. The mean value of Ki-67+ cells in odontogenic keratocysts linings (1812.29 +/- 606.47 cells/mm2) were significantly higher than that of dentigerous (944.43 +/- 58.98 cells/mm2) and radicular cysts (610 +/- 26.4 cells/mm2) (P < 0.01). Negative reactions were obtained in the normal oral epithelium. CONCLUSION: The results demonstrate that there are differences in Ki-67 expression between epithelial linings of the major odontogenic cysts, which were consistent with odontogenic keratocysts having a greater proliferative capability than dentigerous and radicular cysts. It also indicates differences in proliferation and differentiation processes within these lesions.

Cell Division↗

PubMed2001

[Evaluation of the effects of two operative option in the treatment of orbital fractures].

OBJECTIVE: In order to explore the treatment and it's clinical effects of orbital fractures. METHOD: 34 patients were separately treated with nasal endoscopic surgery and external nose incision surgery. RESULT: The total effective rate of nasal endoscopic surgery and external nose incision surgery was 90.0%, 91.6% respectively. There was no significant difference between the two groups (P > 0.05). CONCLUSION: Treating orbital fractures under nasal endoscopic surgery has advantages such as no incision on face, less damage, clear view and easy recheck after operation. It is the best way to treat this kind of disease.

Adolescent↗

PubMed2001

[Measurement of serum neopterin levels in patients with nasopharyngeal carcinoma and its significance].

OBJECTIVE: To evaluate the relationship between serum neopterin levels and nasopharyngeal carcinoma and its clinical significance. METHOD: The serum neopterin levels were determined in 54 patients with nasopharyngeal carcinoma (NPC group) and 32 healthy adults (normal group) by ELISA. RESULT: The serum neopterin levels in NPC group were significantly higher than that of in normal group (P < 0.001). The serum neopterin levels in UICC-TNM stages were undifferentiated (P > 0.05). The serum neopterin levels in patients with no lymph node metastasis were lower than that of in lymph node metastasis (P < 0.05). The serum neopterin levels decreased significantly after disappearance of tumor and its lymph node treated by radiotherapy (P < 0.01). CONCLUSION: Cellular immunity mediated by macrophages might be involved in the pathogenesis of nasopharyngeal carcinoma and the measurement of the serum neopterin may be a useful objective index to evaluate cellular immunological functions and curative effects.

Adult↗