Biomedical subjects
Publications and source records attributed to Z Yi.
Adsorption layers of n-dodecanol at the water/air interface show phase transitions at low temperatures [Vollhardt, Fainerman, Emrich, J. Phys. Chem. B 104 (2000) 8536]. Using a drop shape technique it is shown that the dilational elasticity disappears in the coexistence region of the adsorption layer. The relaxation time between the condensed and liquid-like surface states is in the sub-second time range.
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Although short-course antiretroviral therapy is efficient in reducing mother-to-child transmission (MTCT) of HIV-1, it does not prevent transmission during the breastfeeding period. There is therefore an urgent need to test various approaches, including HIV-1 vaccination, to try to prevent postnatal transmission of HIV-1 in breastfeeding populations in developing countries.
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Our sensitivity analysis shows that the adjusted TFR'(t) using the formula of Bongaarts and Feeney (1998), which assumes an invariant shape for the fertility schedule, usually does not differ significantly from an adjusted TFR"(t) that allows the shape of the fertility schedule to change at a constant annual rate. Because annual changes in the shape of the fertility schedules often are approximately constant except in abnormal conditions, the Bongaarts-Feeney (B-F) method is generally robust for producing reasonable estimates of the adjusted TFR'(t). The adjusted TFR'(t) neither represents any real cohort experiences from the past nor forecasts any future trend. It merely provides an improved reading of the period fertility measure, which reduces the tempo distortion.
Insulin-like growth factor-binding proteins (IGFBP) regulate the biological functions of insulin-like growth factors (IGF) and may affect cell growth through IGF-independent actions. Growth factors and hormones have been shown to alter IGFBP production by target cells suggesting that the effects of these factors may be partially mediated by the local production of IGFBP. Growth factors, including IGF-I, transforming growth factor-beta1 (TGF-beta1), and basic fibroblast growth factor (bFGF) have potent effects on satellite cell proliferation and differentiation, and some of these factors have been shown to alter IGFBP production in various cell types. Consequently, some of their actions on muscle satellite cells may be mediated by the local production of IGFBP. In this study, we measured the effects of IGF-I, bFGF, and TGF-beta1 on IGFBP production by primary porcine satellite cell (PSC) cultures after first determining physiologically active concentrations of these growth factors to use according to [3H]thymidine incorporation dose responses. There is little information on the effects of these growth factors on IGFBP production in primary porcine myogenic cells due to the confounding affects of contaminating nonmuscle fibroblasts. Comparative studies show that primary porcine satellite cells produce IGFBP-3 and -5 whereas porcine muscle-derived nonfusing cells (FIB) produce IGFBP-2 and -4 but not IGFBP-3 or -5. Because of this, our investigations have focused on growth factor-induced production of IGFBP-3 and -5 in primary porcine satellite cells cultures. Both IGF-I and bFGF exhibited dose-dependent increases in [3H]thymidine incorporation with increasing concentration from 1 to 50 ng/mL (P < 0.05), whereas TGF-beta1 caused a dose-dependent decrease from 0.01 to 0.5 ng/mL (P < 0.05). When 20 ng/ mL of IGF-I was added to the media, IGFBP-3 was increased approximately 65% (P < 0.05) and IGFBP-5 was increased approximately twofold (P < 0.05). The addition of 0.5 ng/mL TGF-beta1 caused more than a two-fold increase in IGFBP-3 (P < 0.05) and approximately an 80% increase in IGFBP-5 (P < 0.05), whereas 50 ng/ mL of bFGF caused approximately 40% (P < 0.05) and 70% (P < 0.05) increases in IGFBP-3 and -5, respectively. Neither IGFBP-3 nor -5 was detectable in the conditioned media from fibroblasts whether or not IGF-I, TGF- beta1 or bFGF were present. These data suggest that the effects of IGF-I, TGF- beta1 and bFGF on porcine satellite cells may in part be through the autocrine/ paracrine production of IGFBP-3 and -5 by porcine satellite cells.
OBJECTIVE: To examine the therapeutic effect of oncogene c-myb antisense oligodeoxynucleotide (AON) on rat C6 glioma in vivo. METHODS: C6 glioma cells were implanted into the subcutis of nude mice, the animals were randomly divided into three groups (12 mice respectively) when the tumor grew about 10 mm in size, and the mice with subcutaneous tumor foci were treated with sense oligodeoxynucleotide (SON), AON and normal saline. Three animals of each group were killed after treatment at 4, 8, 12 and 16 days respectively. The dynamic growth manifestations, features, histopathological changes and apoptosis of the glioma in each group were observed. RESULTS: AON suppressed the growth of C6 glioma cells, the suppression rates being 66.7%, 71.4%, 72% and 73% at 4, 8, 12, 16 days respectively (P < 0.05). The changes in weight were concurrent with the variations of tumor volume, the tumor weight of AON groups was significantly decreased (P < 0.05). The immunohistochemical assay showed the expression of c-myb proto-oncogenes was significantly decreased in AON groups (P < 0.05). The flow cytometry analysis found the apoptosis cell percentage of AON groups to be 13.4%, 27.1%, 46.1% and 48.4% at 4, 8, 12 and 16 days respectively, and this percentage of AON groups was about 3.5 times the apoptosis cell percentage of SON and control groups at the corresponding time. In addition, noticeable inflammatory infiltration and calcification were observed after the treatment with AON. CONCLUSION: The above findings indicate that c-myb gene might be associated with the suppression of carcinogenesis in brain glioma, and oncogene c-myb might be chosen as a target for antisense gene therapy of gliomas.
OBJECTIVE: To investigate the relationship between herpesviridae and malignant or benign laryngeal diseases. METHOD: 128 paraffin-embedded laryngeal squamous cell carcinoma and laryngeal epithelium hyperplastic lesions were detected by polymerase chain reaction (PCR) and PCR-ISH for herpesviridae. RESULT: HSV-1 was detected in 10 cases by PCR, among them 3 were laryngeal squamous cell carcinoma (LSCC), 1 was carcinoma in situ(CIS), 4 were laryngeal polyps and 2 were laryngeal keratosis. Except 1 LSCC and 1 CIS 8 of 10 cases were positive while detected by PCR-ISH. In benign diseases, signals were shown from basal layer to superficial cell; in malignant lesions, the signals were scattered in the diseases. CONCLUSION: Most of laryngeal diseases were not related to herpesviridae, but HSV-1 may acts as initiator in the development of a few cases.
OBJECTIVE: To evaluate the role of human papilloma virus (HPV) infection and inactivation of p16 gene in laryngeal papilloma (LP) and laryngeal squamous cell carcinoma (LC). METHODS: HPV consensus primers direct in situ polymerase chain reaction (ISPCR) and immunohistochemical method were applied to detect the presence of HPV genomes (1, 6, 8, 11, 13, 16, 18, 30, 31, 32, 33, 45, 51) and the expression of p16 protein respectively in 93 cases of formalin-fixed, paraffin-imbedded specimens, which contained 46 cases of LPs [adult-onset laryngeal papilloma (ALP) 21, juvenile-onset laryngeal papilloma (JLP)25], 26 cases of LCs, 6 cases of normal tissues adjacent to carcinoma, and 15 cases of vocal noduli. RESULTS: (1) The difference of positive rates of HPV-DNA in JLP group (84%, 21/25) and other groups were statistically significant (chi 2 test, P < 0.05). The difference of positive rates of HPV-DNA in ALPs(38.1%, 8/21), in LCs(19.2%, 5/26), in vocal noduli(0%, 0/15), and in normal tissues adjacent to carcinoma(0%, 0/6) were not significant statistically (chi 2 test or Fisher's exact probability test, P > 0.05). (2) The positive rates of expression of p16 protein in ALP group(57.1%, 12/21) and LC group(38.5%, 10/26) were significantly lower than that in vocal nodule group(93.3%, 14/15), in JLP group(88%, 22/25), and in normal tissues adjacent to carcinoma group (100%, 6/6) (chi 2 test or Fisher's exact probability test, P > 0.05). There were no significant differences of positive rates of expression of p16 protein between ALP group and LC group, and between JLP group and vocal nodule group (chi 2 test, P > 0.05). (3) In LPs, the difference of positive rates of p16 protein expression between HPV positive cases and HPV negative cases was significant statistically (chi 2 test, P < 0.05). In LCs, there was no difference in p16 protein expression rate between the two teams(Fisher exact probability test, P > 0.05). CONCLUSION: The pathogenesis of JLP is closely associated with HPV infection and not associated with the inactivation of p16 gene. Conversely, the pathogenesis of ALP and LC is associated with the inactivation of p16 gene and not associated with the HPV infection.
The rissooidean snail genus Oncomelania is of medical interest as various taxa are hosts for the human blood fluke Schistosoma and the lung fluke Paragonimus; because of close co-evolved host-parasite-relationships, snail diversity may reflect parasite diversity. There is a considerable amount of confusion regarding the identity of smooth- and ribbed-shelled populations of Oncomelania hupensis in eastern China. We therefore studied the genetic variation, population structure, phylogenetic relationships and ecology of five smooth- and five ribbed-shelled populations in Hubei, Hunan, Anhui, Zhejiang, and Jiangsu provinces. Based on sequencing data of a fragment of the mitochondrial gene for cytochrome oxidase I from 80 individuals, we found little genetic variability within the ingroup-individuals studied here (average pi=0.01922). Moreover, within the ingroup, smooth-shelled individuals cluster together with ribbed-shelled individuals. We therefore consider all smooth- and ribbed-shelled populations of Oncomelania throughout the lower Yangtze River basin to belong to the subspecies O. hupensis hupensis. Our data indicate that ribbing in O. h. hupensis is associated with the annual floods of the Yangtze River. The greatest haplotype (d(H)) and nucleotide diversities (pi) are found in aggregates of ribbed-shelled snails along areas of the Yangtze River drainage subject to flooding. In areas not affected by flooding, the shells are smooth and genetic diversity decreases significantly.
OBJECTIVE: The goal of this study was to investigate the nature of juvenile nasopharyngeal angiofibroma. STUDY DESIGN: Twenty-five excised tumors were studied morphologically to confirm the histopathologic features of the tumor. METHODS: Paraffin sections of all tumor specimens were stained with hematoxylin-eosin for elastic fiber, polyclonal antibody to factor VIII-related antigen and monoclonal antibodies to smooth muscle actin, estrogen receptor, and progesterone receptor. A quantitative assessment of the vascular component changes was also performed in 14 cases. Ultrathin sections of 5 tumors were studied electromicroscopically. Particular attention was paid to the progressive changes of both vascular and fibrous components as well as their mutual relationship. RESULTS: (1) Beneath the endothelium of the vascular component, there was a thin layer of spindle cells; these cells had a positive reaction for smooth muscle actin, thus proving to be pericytes. (2) The actively proliferating site of the tumor was usually at the peripheral portion, with abundant vascular element lined by plump endothelial cells. (3) At the central and base locations, the growth of tumor tissue usually appeared to be in a relatively resting state. The vascular component decreased in amount as the extracellular collagenous fibers increased. CONCLUSIONS: Because of the bicellular mixed composition of the vascular component and the tendency of synchronous maturation of both vascular and fibrous elements, it is suggested that juvenile nasopharyngeal angiofibroma is similar to most hemangiomas by nature and is likely a vascular hamartoma or a pathologic and reactive proliferation of vessels.
OBJECTIVE: To investigate prenatal diagnosis of fetal congestive heart failure (CHF) by Color Doppler Flow Imaging (CDFI) and pulse Doppler Ultrasound (PU). METHODS: 3,841 pregnant women were detected by ultrasound. Maternal-placental-fetal circulation surveillance by high resolution Doppler ultrasound was performed in 302 high-risk pregnancies. The diagnosis of CHF is dependent upon (1) The cardiac area/chest area ratio > 0.33; (2) An abnormal umbilical vein pulsation; and (3) Tricuspid regurgitation. RESULTS: There were six deaths that all had abnormal umbilical vein pulsation and five cases who had C/T area ratio > 0.33. CHF accounted 0.17% in all the pregnancies and 2% in high-risk pregnancies. CONCLUSIONS: The results suggest that blood velocity recording abnormal pulsed sign in the umbilical veins and C/T area ratio of the fetus can give valuable clinical information with regard to the presence of fetal CHF. Fetus with CHF almost always had poor outcome. CDFI and PU may have implications for fetal diagnostic work-up and prognosis.
OBJECTIVE: Otosclerosis is a disease of hereditary liability. It might be related to an autosomal dominant inheritance. The genetic penetrance is determined by multifactorial influences. This paper was designed to study the reasonable strategies for prevention and treatment of this disease. METHODS: A retrospective review derived from data of the management and follow-up of 14 cases in 6 families. According to the special pathological features of active phase of the otospongiosis, the suitable strategies for prevention and treatment of this disease were suggested. RESULTS: Diagnosis of 14 cases were confirmed by audiological, operative and/or pathological examinations. Eleven of fourteen cases underwent stapedectomy, in which 10 cases had the surgery on the ear with severer hearing loss, and one case on both sides. In all of the surgical cases, hearing levels improved significantly. Three cases have not yet received the stapedectomy, in which two cases scheduled for the surgery are currently treated by chondroitin sulfate and one case refused the surgical treatment due to financial shortage. CONCLUSION: Examination of the ear function at regular intervals (6-12 months) is recommended for the adults among the family members with high-incidence of otosclerosis. Audiological and radiological examination play an important role in early diagnosis and treatment. Attention should be paid to the medicine for management and prevention of this disease. Stapedectomy is an optimal choice for clinical otosclerosis not only due to its capacity to improve the hearing level but also to prevent the advance of hearing loss. Hearing aid is the suitable choice if stapedectomy is contraindicated.
OBJECTIVE: Hypertrophic cranial pachymeningitis(HCP) is a rare disease which might be misdiagnosed. One typical case of otogenic hypertrophic cranial pachymeningitis (HCP) associated with edema of the temporal lobe and organic mental disorder was reported. Literatures associated with HCP were reviewed for reference. METHODS: In July, 1997, a 26-year-old man was admitted for right-sided severe headache, dizziness, nausea, vomiting, facial and abducens nerve palsy. MRI and CT revealed inflammation in the temporal bone and locally thickened dura mater with obvious enhancement as a band in the petrous apex and nearby tentorium cerebellum. The patient then underwent operation including decompression of the facial nerve, labyrinthectomy, and eradication of the inflammatory cells in the mastoid and petrous portion. Postoperatively, the clinical signs disappeared except hearing loss. Seven months later, the patient suffered from mental disorder with interrupted excitement to hit and abuse the family members. He was then treated in a psychosis hospital but no improvement could be seen. On May 13, 1998, MRI and the enhanced MRI demonstrated diffuse thickened tentorium cerebellum and dura mater in the middle cranial fossa. The inferior portion of the temporal lobe was obvious edema. The internal carotid artery was partially occluded due to the thickened wall of cavernous sinus. RESULTS: Hence, the diagnosis of HCP associated with edema of temporal lobe and organic mental disorder was established. The patient was cured by high dosage of penicillin. CONCLUSION: MRI is an essential method for diagnosis of HCP. Antibiotic was an effective treatment.
Polyurethane/liquid crystal composite membranes were first suggested to be used as biomaterials. In our work, three series of polyurethane/liquid crystal composite membranes based on three different kinds of liquid crystal compounds [N-(-4-methyoxybenzylidene)-4'-heptylaniline, 4-pentyl-4'-nitrile-biphenyl and cholesteryl oleyl carbonate] were prepared by casting on glass plates from a tetrahydrofuran (THF) solution of polymer and liquid crystal at room temperature. In our opinion, the formation of liquid crystal phase on the composite membrane surface is the basic requirement for getting better biomaterial. The result of this work is in accordance with our opinion. The effect of liquid crystal content on the formation of liquid crystal phase was identified by the observation of optical polarization microscopy (OPM). The results showed that the content of liquid crystal in composite membrane must be more than 30% (wt) in order to form liquid crystal phase on the composite membrane surface. The blood-compatibility of the composite membranes was assessed from SEM observation of the platelet's adhesion to membrane's surface, blood clotting time and haemolysis ratio. The observation of platelet's adhesion showed that the platelets gathered together on the pure polyurethane films, but the amount of platelets which were adherent on the surface covered by the liquid crystal phase was fewer than that of pure polyurethane film when platelet-rich plasma was allowed to be in contact with the membranes for 1 h at room temperature. The determination of blood clotting time and haemolysis ratio showed that these polyurethane/liquid crystal composite membranes, in which the content of liquid crystal was more than 30% (wt), appear to be beneficial in improving the blood compatibility and reducing the thrombogenicity.
We examined the molecular pathogenesis of graft-versus-host disease-associated (GVHD-associated) liver injury in mice, focusing on the role of chemokines. At the second week after cell transfer in the parent-into-F1 model of GVHD, CD8(+) T cells -- especially donor-derived CD8(+) T cells -- infiltrated the liver, causing both portal hepatitis and nonsuppurative destructive cholangitis (NSDC). These migrating cells expressed CCR5. Moreover, macrophage inflammatory protein-1alpha (MIP-1alpha), one of the ligands for CCR5, was selectively expressed on intralobular bile duct epithelial cells, endothelial cells, and infiltrating macrophages and lymphocytes. Administration of anti-CCR5 antibody dramatically reduced the infiltration of CCR5(+)CD8(+) T lymphocytes into the liver, and consequently protected against liver damage in GVHD. The levels of Fas ligand (FasL) mRNA expression in the liver were also decreased by anti-CCR5 antibody treatment. Anti-MIP-1alpha antibody treatment also reduced liver injury. These results suggest that MIP-1alpha-induced migration of CCR5-expressing CD8(+) T cells into the portal areas of the liver plays a significant role in causing liver injury in GVHD; thus, CCR5 and its ligand may be the novel target molecules of therapeutic intervention of hepatic GVHD.
The molecular pathogenesis of diabetes remains poorly understood because of the genetic complexity of the disease. One possibly effective approach to elucidate the pathogenesis is to study an animal model with a similar phenotype. The TSOD (Tsumura, Suzuki, Obese Diabetes) mouse, a newly developed animal model, exhibits both diabetes and obesity with marked hyperinsulinemia and hypertrophy of the pancreatic islets and might represent a common form of obese type 2 diabetes in humans. Phenotypic characterization revealed that the TSOD mouse had both insulin resistance and impaired glucose-stimulated insulin secretion. A comprehensive genetic dissection of diabetes and obesity has been performed using F1 and F2 progeny between the TSOD and control BALB/cA strains. A genome-wide screen for loci linked to glucose homeostasis and body weight allowed us to map three quantitative trait loci (QTLs) involved in this disorder. The major genetic determinant of blood glucose levels was identified on chromosome 11. Furthermore, two independent QTLs involved in controlling body weight were found on chromosomes 1 and 2. The QTL on chromosome 2 also affected insulin levels significantly. Each QTL has distinct effects on different traits and a different mode of inheritance. Our study indicates that hyperglycemia and obesity are clearly controlled by distinct combinations of genetic loci in this mouse model and provides insights into the genetic basis of common forms of human type 2 diabetes with obesity.
A retrospective study of 68 patients was carried out to assess the complications arising from the use of reconstruction plates in the maintainance of space and contour following mandibular segmental resection. Skin or mucosal perforation, plate fracture and loss of screw retention were the main complications. The most susceptible sites to screw loosening in the plates were situated nearest to and farthest from the resection margin on the proximal residual segments. Some of the possible causative biomechanical mechanisms of plate failure were studied using photoelastic models simulating the types of mandibular defect and plate fixation. Isochromatic fringe analysis was used to analyse stress lines in the bone surrounding screws. It was found that, during functional loading, moment and shear forces produced high concentrations of squeeze and press stress in this bone, causing bone resorption with consequent loss of screw retention.