Volume 112  ·   Issue 05  ·  1999

OBJECTIVE To detect the resistant mechanisms of Candida albicans to fluconazole (FCZ) at molecular biology level, since the resistance mechanisms of azole antifungal agents have been the focus of attention these years. METHODS Thirty-two FCZ-resistant C. albicans were selected as our test strains (MICs > or = 64 micrograms/ml). With 14-alpha-demethylase gene (ERG16 gene, target enzyme encoding gene of azoles) as our object, we chose six sets of primers from the ERG16 gene to amplify the interested fragments, and conducted Southern blot hybridization, restriction fragment length polymorphism (RFLP), and single strand conformation polymorphism (SSCP) analysis for the fragments which were amplified by the six sets of primers, and pre-resistant sensitive strains were used as controls. Three representative fragments, A66, D66 and E78, were selected to be cloned and sequenced. RESULTS The polymerase chain reaction (PCR) amplification showed that several tested strains were negative for some primers. However, our Southern blot analysis reminded that their resistance did not result from the lack of target enzyme coding gene. SSCP analysis showed that differences were noted between the resistant and sensitive strains and inter-resistant strains. Statistical analysis showed that the most variable sequence lied in the amplifier of the sixth pair of primer, and all the tested 32 strains showed positive results. In the 11 mutation points we found, five resulted in amino acid alterations. It is likely that one or more mutational alterations (alone or in combination) might lead to the expression of an enzyme highly resistant to the inhibitory action of FCZ which in turn is responsible for the FCZ resistant trait in these strains. CONCLUSIONS One or more mutational alterations might lead to the azole resistant trait in this strains.

OBJECTIVE To study 4 cases of adult T-cell leukemia/lymphoma (ATLL) associated with cutaneous lesions for clinicopathology, immunophenotype, human T-cell leukemia/lymphoma virus type I (HTLV-I) provirus DNA and their ultrastructure. At the same time, HTLV-I provirus DNA of ATLL patients were also compared with 18 cases of cutaneous lymphoma (CL), two cases of actinic reticuloid as well as two cases of lymphocytic infiltration. METHODS Immunohistochemistry studies were carried out on the infiltrating cells using monoclonal antibodies against CD45-RO, CD20, CD68 on paraffin-embedded sections by ABC method and using monoclonal antibodies against CD3, CD4 and CD8 with indirect immunofluorescence (IIF) on frozen sections. Skin biopsies were examined by electron microscope. Serum and bone marrow cells were tested for antibodies against HTLV-I-associated antigen by IIF, and HTLV-I provirus DNA was examined by PCR method. RESULTS The research showed four patients with ATLL manifesting cutaneous lesions, were subsequently found with additional systemic symptoms, as extensively enlarged superficial lymph node, abnormal increased IL-2 receptor, flower-like cells in their peripheral blood and marrow. The HTLV-I provirus DNA was positive in the peripheral blood, bone marrow, cutaneous lesions and lymph node biopsy specimens by using PCR amplification of specific HTLV-I fragment while 18 cases of the CL were negative for HTLV-I. The special ultrastructure of skin lesions was also found in ATLL patients. CONCLUSIONS The cutaneous involvement in ATLL is a type of cutaneous T cell lymphoma (CTCL) but shows some differential immunological markers for differential diagnosis. The examination of HTLV-I antibodies or HTLV-I provirus DNA is necessary for diagnosis of ATLL. The ultrastructural characteristics in skin lesions of ATLL were of atypical lymphocytes and mononuclear cells invading the epidermis, and the mononuclear cells are possessing the phagocytic function and phagocytizing the degenerated epidermic cells or lymphocytes.

OBJECTIVE To investigate the differences in bone interface between titanium and stainless steel pedicle screws in the lumbar spine. METHODS Eighteen adult mini-pigs that underwent total laminectomy, posterolateral spinal fusion (L4-L5) were randomly selected to receive stainless steel (9) or titanium pedicle screw devices (9). In both groups, the devices were CCD (Sofamore Danek) type with the same size and shape. The postoperative observation time was 3 months. Screws from L4 were harvested along their long axis of pedicle for histomorphometric study. Bone-screw interface and bone volume from thread were examined using linear intercept techniques. Mechanical testing (torsional test and pull-out test) was performed on the screws from L5. RESULTS The titanium screw group had a significantly higher maximum torque (P<0.05) and angle related stiffness (P<0.05) measured by torsional test. In the pull-out tests, no differences were found between the two groups in relation to the maximum load, stiffness and energy to failure. Direct bone contact with the screw in percentage was 29.4% for stainless steel and 43.8% for titanium (P<0.05). No differences in the bone purchase between the vertebral body part and pedicle part were found. CONCLUSIONS Pedicle screws made of titanium have a better bone-screw interface binding than screws made of stainless steel. Torsional tests are more informative for bone-screw interface study. Pull-out tests seem less valuable when comparing bone purchase of screws made from different materials.

OBJECTIVE To determine whether the antiatherogenic effect of L-arginine is due to an inhibition of vascular cell adhesion molecule-1 (VCAM-1) expression in the aortae of hypercholesterolemic rats. METHODS Twenty-four male Wistar rats were randomized into three groups: Group NC with normal diet (NC, n = 8), Group CC with 4% cholesterol and 1% cholic acid diet (CC, n = 8), Group AC with 4% cholesterol and 1% cholic acid diet supplemented with 3% L-arginine HCl in the drinking water (AC, n = 8). Eight weeks later, the blood samples were collected for biochemical studies, and the aortae were harvested for RT-PCR and immunohistochemical studies. RESULTS The results showed that dietary L-arginine supplementation reduced expression of VCAM-1 in protein level and mRNA level. CONCLUSIONS Inhibitory effect of dietary supplementation of L-arginine on VCAM-1 expression may be one of the mechanisms of its antiatherosclerosis.

OBJECTIVE To observe the effects of nerve growth factor (NGF) on nitric oxide (NO) release and constitutive nitric oxide synthase (cNOS) gene expression in oxygen/glucose deprived cortical neuron cultures. METHODS Neuron viability was measured to assay NGF effect. The content of NO and the expression of cNOS mRNA were determined by spectrofluorometric method and Northern blot respectively. RESULTS There were a marked increase of neuronal death and NO release in oxygen/glucose deprived cultures for 24 h. NOS inhibitor, NG-nitro-L-arginine methyl ester (NAME) 100 mumol.L-1 and NGF 50, 100 micrograms.L-1, significantly increased neuronal surviving and decreased NO release. However, NGF (50, 100 micrograms.L-1) had no significant effects on neurotoxicity induced by sodium nitroprusside (SNP) 300 mumol.L-1 in cortical cultures. Hemoglobin (Hb), which binds NO, completely prevented hypoxia/hypoglycemia- or SNP-induced cell death and NO release at 500 mumol.L-1. NGF 100 micrograms.L-1 significantly attenuated cNOS gene expression. CONCLUSIONS NO can mediate the neurotoxicity of hypoxia/hypoglycemia, and NGF can protect cortical neurons against oxygen/glucose deprivation-induced toxicity via inhibiting the activity of cNOS and suppressing the release of NO.

OBJECTIVE To investigate the effect of cytokines on in vitro bone resorption by cells isolated from giant cell tumor of bone. METHODS Mononuclear stromal cells and multinucleated giant cells (MGC) were isolated from 11 cases of giant cell tumor of bone (GCT) and their bone resorption capability in an in vitro cell-bone resorption model were tested. Expressions of some cytokines were detected by immunohistochemistry, Western blotting analysis and Enzyme-linked immunoabsorbent assay (ELISA) in the GCT. RESULTS The RESULTS showed that MGCs of GCT had capability to resorb bone matrix directly. Fibroblast-like stromal cells (FC) could not only resorb bone matrix directly, but also secret unknown factors to facilitate bone resorption of MGC. Exogenous TNF-alpha could significantly increase the bone resorption by both kinds of stromal cells, while exogenous IL-1 did not. Expression rate of M-CSF and level of TNF-alpha in GCT were higher than in osteosarcoma and normal serum. CONCLUSIONS The characteristic bone resorption behavior of GCT might be caused by its three major cell components. The M-CSF and TNF-alpha could promote their bone resorption capability.

OBJECTIVE To test whether minimally modified low-density lipoprotein (MM-LDL) can stimulate the arterial cells expressing MCP-1 in vivo and thus induce monocyte adherence to endothelium. METHODS An animal model was constructed to study the function of MM-LDL in vivo. MM-LDL (600 micrograms/ml) was perfused into a segment of the femoral artery of rabbits (both ends of which were occluded with removable ligatures). After exposure to MM-LDL for 2 h, the arterial segments were taken out 6 or 18 h later. The arteries were subjected to in situ hybridization with 35S-labeled antisense monocyte chemotactic protein-1 (MCP-1) RNA probe and processed for scanning electron microscopy. RESULTS The expression of MCP-1 mRNA of the arterial endothelial cells and smooth muscle cells were increased by 60% and 90% 6 h after perfusion and had a 3.2 folds and 1.6 folds increase 18 h after perfusion respectively as compared with control (arteries perfused with saline). There was also apparent monocyte adherence to the endothelium observed by scanning electron microscopy. CONCLUSIONS MM-LDL can stimulate vascular cells in expressing MCP-1 mRNA and enhance monocyte adherence to endothelium in vivo.

OBJECTIVE To analyze the effectiveness of endovascular embolization on treatment of traumatic carotid-cavernous fistula (TCCF). METHODS From 1986 to 1997, 482 cases of traumatic carotid-cavernous fistula were treated by endovascular embolization in the Beijing Neurosurgical Institute. Several kinds of balloon-catheter were used for embolization. External carotid-cavernous fistulas and rare carotid-cavernous fistulas (CCF) with minute leakage were treated by cyanoacrylate or coils. Although artery approach was applied in most cases (477 cases), vein approach showed its own advantages in some special cases. RESULTS We found a special "bileakage sign" indicating multileakage of TCCF, which was never mentioned before. All 482 cases were embolized successfully, and 405 cases maintained the patency of internal carotid artery (ICA). No treatment-related deaths occurred and the symptoms and signs of 462 cases were relieved after embolization. Emergency embolization was needed in some conditions such as serious epistaxis, delayed or repeated subdural hematoma, and rapid visual impairment. CONCLUSIONS Endovascular embolization of TCCF is a safe and efficient method. Carefully selected operation time, operative approach, and materials are the essential factors to reach a best result.

OBJECTIVE To study the clinical results of hepatic radioembolization with Yttrium-90 (90Y) glass microspheres in the treatment of primary liver cancer. METHODS Seventeen patients with liver cancer were treated with glass microspheres from August 1996 to May 1998. Hepatic radioembolization with 90Y and lipiodol-ultrafluid was used. Percutaneous port-catheter system (PCS) implantations via femoral artery were performed in 12 patients. RESULTS In the 17 patients, their mean ratio of absorbed doses between tumor and normal liver was 2.4:1. CT showed a significant reduction in tumor size in 11 of the 17 patients. Average survival was 19.5 months. The indwelling catheters of all the 12 patients were patent and no catheter tip locations were found. CONCLUSIONS 90Y glass microsphere is one of the best radioisotopes. Not only good responses to the therapy of 90Y glass microspheres can be achieved in patients with metastatic liver cancer, but also in those with primary liver cancer, specially the localized or hypervascular mass. The patients with massive arterioportal shunt should not be limited to this form of radiation therapy. The percutaneous PCS implantation via the femoral artery is a new passageway for the treatment of primary liver cancer with 90Y glass microspheres and other interventional therapy.

OBJECTIVE To investigate the effects of ischemic preconditioning (PC) and ATP sensitive K+ channels (KATP(+) opener nicorandil on reperfusion arrhythmias and electrophysiology. METHODS Langendorff-perfused rat hearts were subjected to ischemic PC with three cycles of 2 minutes of global ischemia or infusion of KATP+ opener nicorandil with subsequent 5 minutes global ischemia and reperfusion. The incidence of reperfusion arrhythmias, ventricular fibrillation threshold (VFT), effective refractory period (ERP) and monophasic action potential duration (MAPD) of the left and right ventricles were compared to those from control rat hearts. RESULTS The results indicated that PC reduced the incidence of total arrhythmias and ventricular fibrillation during reperfusion (P<0.05, vs controls). PC markedly delayed the onset of arrhythmia after reperfusion (P<0.01, vs controls). PC significantly enhanced the VFT values during reperfusion and shortened the ERP and the MAPD during ischemia. VFT was restored more rapidly than that in controls. KATP+ opener nicorandil neither reduced the incidence of total arrhythmias and VF nor delayed arrhythmia onset. Nicorandil shortened ERP and MAPD90 without enhancing the VFT values, and VFT returned to normal as slowly as that in controls. CONCLUSIONS We conclude that PC protects the globally ischemic rat hearts from reperfusion arrhythmias. The antiarrhythmic effect of PC is likely to be related to a significant increase of VFT. KATP+ opener nicorandil has no potential antiarrhythmic action and KATP+ channels may not play a major role in the antiarrhythmic effects of ischemic PC in isolated rat hearts.

Purpose To summarize the major achievements of Chinese work on the epidemiology and prevention of hemorrhagic fever with renal syndrome (HFRS) in recent years, and to give a general review on the present situation of HFRS in China. Data sources Reviews and papers published in Chinese journals, relevant to the objectives, written or collected by the author; and the research work of the author. Study selection An outline was drafted according to the purpose given above, and the relevant materials and data were grouped together into different items outlined. Data extraction All the materials and data extracted were published or specially assessed. Results HFRS was first recognized in the northeastern China in 1931. It has been found prevalent also in many other parts of China since 1955, and presently, 28 out of 31 provinces (autonomous regions, or municipalities) have been proved to be its endemic areas. The total number of cases is 1,256,431 from 1950 to 1997, with 44,304 death (3.53%). 50-100 thousands of cases could be registered annually since 1981 when the presence of the Rattus-type HFRS was first identified serologically in China, with the highest peak in 1986 (115,985 cases). Three types of endemicity have been differentiated: the Apodemus-type, the Rattus-type and the mixed type of the two, by their peculiar seasonal distributions of cases and by methods of serotyping (HI, Mabs serotyping kits). The epidemiologic features of the Rattus-type HFRS are quite different from that of the Apodemus-type. 67 species of vertebrates were found to harbor hantavirus antigen or antibodies, but the chief or primary reservoir hosts are Apodemus agrarius and Rattus norvegicus only. Besides the commonly recognized enzootic mode of transmission (via contacts with the reservoir rodents or their excreta), mite transmission (including certain species of gamasid mites, and chigger mites) has been identified as the potential vectors and reservoir hosts with HFRS. Vertical transmission had been found in pregnant patients with HFRS, and in all three chief host rodents (Apodemus agrarius, Rattus norvegicus, the laboratory rats). The relatively high inapparent infection rates in the population of endemic areas of the Rattus-type HFRS after big outbreaks (8%-20%) are suggested to play a significant role in the gradual decline of the incidence of HFRS in that areas. Three kinds of inactivated vaccines against HFRS (the golden hamster kidney cell vaccine, the Mongolian gerbil kidney cell vaccine and the purified suckling mouse brain vaccine) have been successively developed and proved highly effective in the prevention of HFRS. Conclusion Chinese workers on the epidemiology and prevention of HFRS in China have accomplished great achievements since 1981. As the relatively high annual incidence of HFRS sustained in recent years, control measures have to be reinforced. Many problems of HFRS and hantavirus infections are still not well understood or unclear, such as the poly-host nature, and the multi-modes of transmission, the natural history of hantaviruses and their genetic variation occurred in nature etc. The task for effective control of HFRS and the research on its epidemiology in China should be held on a high priority.