Biomedical subjects

Z Wu

Publications and source records attributed to Z Wu.

At least 397 records · Page 22Linked to original sources

PubMed1998

Detection of verotoxin-producing Escherichia coli O157:H7 by multiplex polymerase chain reaction.

We constructed primers for multiplex polymerase chain reaction (PCR) to detect verotoxin-producing Escherichia coli (VTEC) O157:H7. The multiplex PCR primers were designed from the sequence of the flagellin structural gene of Escherichia coli flagellar type H7 (GenBank under accession number L07388), and from the sequence of the rfbE gene of Escherichia coli O157:H7 (GenBank under accession number S83460). In addition to these primers, we used a primer pair reported by Karch and Meyer (J. Clin. Microbiol. 27: 2751-2757, 1989) to amplify various VT genes from VTEC. All of the examined specimens (18 isolates) of VT-producing E. coli O157:H7 showed a positive result by the multiplex PCR test with the three sets of primers. The sensitivity of detection for VT-producing E. coli O157:H7 was shown to be at least 3,000 cells per PCR tube.

Animals↗

PubMed1998

Capacitative Ca2+ entry is involved in cAMP synthesis in mouse parotid acini.

Muscarinic receptor interaction leading to augmentation of isoproterenol-stimulated cAMP accumulation in mouse parotid acini involves Ca2+ (28). The effectiveness of capacitative Ca2+ entry and intracellular Ca2+ release on this response was determined in time course studies by using three independent tools to manipulate the free intracellular Ca2+ concentration: the muscarinic agonist carbachol, thapsigargin, and ionomycin. Time course studies revealed that Ca2+ release from intracellular stores by carbachol produced an early rapid increase (0.25-0.5 min) in stimulated cAMP levels, whereas capacitative Ca2+ entry resulted in a sustained increase in stimulated cAMP levels that was blocked by La3+. Capacitative Ca2+ entry, alone, was involved in thapsigargin and ionomycin augmentation of stimulated cAMP accumulation. The inability of phosphodiesterase inhibitors, 3-isobutyl-1-methylxanthine and milrinone, to prevent agonist augmentation of cAMP levels, as well as the finding that the type VIII adenylyl cyclase (ACVIII) is expressed in parotid acini, suggests that capacitative Ca2+ entry augments stimulated cAMP accumulation, at least in part, via activation of this adenylyl cyclase isoenzyme.

1-Methyl-3-isobutylxanthine↗

PubMed1998

Contractile responses to allergen and cholinergic stimulation in bronchus and trachea of cockroach allergen-sensitized guinea pigs.

Airway hyperreactivity is a hallmark of asthma. Yet, the role of allergic sensitization in the hyperreactivity remains controversial. This study examined the effects of airborne cockroach allergen (CRa) sensitization on the contractility of bronchial (BSM) and tracheal (TSM) smooth muscle rings to cholinergic stimulations, and to specific antigen, in vitro. Guinea pigs were actively immunized with CRa, 5 mg (high dose, HD), 0.5 mg (low dose, LD), or saline aerosols (2x/day, 5 days/week, for 4 weeks) and challenged by CRa inhalation 5 days after last exposure. Twenty-four hours postchallenge, the contractions of the TSM and BSM to electrical field stimulation (EFS), acetylcholine (ACh), and to CRa were measured in vitro. In addition, the contraction to these stimuli were also examined in the passively sensitized TSM with the sera of CRa-immunized guinea pigs. The contractile responses of actively immunized and passively sensitized tissues to EFS and ACh were very similar to those of control tissues. CRa induced dose-dependent contractions in both actively immunized and passively sensitized, but not in control, tissues. The CRa-induced contraction was stronger in the HD group than in the LD group (p<0.0001). Leukotriene C4/D4 receptor antagonist LY-171883 inhibited the CRa-induced contraction by 86% in actively immunized TSM, and by 9% in the passively sensitized TSM. Pyrilamine inhibited the contraction by 57% in actively immunized TSM and 70% in passively sensitized TSM. The results indicate that CRa sensitization does not cause increased airway smooth muscle contractility to cholinergic stimulations, but induces antigen-specific contractions in vitro. Leukotrienes appear to play a significant role in the CRa-specific contractions, more in the actively immunized than those in the passively sensitized tissues, while histamine exerts a moderate effect on the CRa-induced contractions.

Acetophenones↗

PubMed1998

Influence of sorghum grain processing on performance and nutrient digestibilities in dairy cows fed varying concentrations of fat.

Forty Holstein cows averaging 85 +/- 50 d in milk were assigned to five dietary treatments for 56 d to determine the effects of ruminal starch degradability and supplemental fat on milk yield and composition and nutrient digestibilities. Treatments were 1) dry-rolled sorghum, no added fat; 2) dry-rolled sorghum plus 2.5% prilled fatty acids; 3) steam-flaked sorghum, no added fat; 4) steam-flaked sorghum plus 2.5% prilled fatty acids; and 5) steam-flaked sorghum plus 5% prilled fatty acids. Fat supplementation at 2.5 and 5% increased the content of fatty acids in diets from 3.0 to 5.4 and 7.7%, respectively. Milk yield was increased 2.0 kg/d when steam-flaked sorghum plus 0 or 2.5% added fat was fed and was 2.4 kg/d higher when prilled fatty acids were fed at 2.5 versus 0%. Cows fed supplemental fat at 5% did not increase milk yield over that of cows fed no added fat. For cows fed 2.5% fat, steam-flaking decreased dry matter intake 12% and increased efficiency of conversion of feed to milk 11%. Milk composition was unaffected by treatments, except that lactose was depressed by fat supplementation. Milk protein yield and efficiency of conversion of dietary protein to milk protein were increased when steam-flaked sorghum was fed. Starch digestibilities were increased from 92.6 to 98.2% when sorghum was steam-flaked compared with dry-rolled and fat supplementation tended to decrease digestibility of neutral detergent fiber. Steam-flaking tended to improve, and the addition of 2.5% fat did improve, the lactational performances of the cows. These effects appeared additive, but 5% fat appeared to be excessive.

Animal Nutritional Physiological Phenomena↗

PubMed1998

[Analysis on the immuno-effects of two different Japanese encephalitis virus vaccines].

319 infants aged 5-18 months were divided in to 2 groups and immunized with Japanese encephalitis virus inactivated vaccine and live attenuated vaccine respectively. Under the detection of serum antibody, a 3.76% serum antibody positive rate was revealed before the immunization. However, after the basic immunization the serum positive rates of the two vaccines reached 59.56% and 56.08% respectively but still under the protective level. The infants were then given booster injection one year later. The serum positive rates reached 94.62% and 98.21% respectively 1 month later. When six months after the booster immunization, the positive rates were 72.34% and 94.74% respectively. According to the results, the following immunization order was recommend. For inactivated vaccine: 2 injections are given with an interval of 7-10 days for basic immunization and booster immunization be given in the second and third years. For live attenuated vaccine: one injection is given for basic immunization then booster dose be given in the second year and 4-5 years later.

Antibodies, Viral↗

PubMed1998

[Relationship between risk-taking behavior and knowledge for HIV infection among young men in Longchuan, Yunnan of China].

OBJECTIVE: To study the relationship between characteristics of risk-taking behavior and knowledge level of HIV infection/AIDS and risk perception of HIV infection among young men in an AIDS epidemic area. METHODS: A cross-sectional survey was carried out among young men aged 18-29 years in 82 villages in Longchuan, Yunnan, China in 1994. Their demographic and behavioral information and knowledge level of AIDS were collected by interviewer administered anonymous questionnaire. RESULTS: A total of 1,548 subjects were interviewed and 433 were drug abusers, including 192 intravenous users with 73% of them sharing syringes with others. Drug abusers were four times more likely to have pre-/extra-marital sex than non-users. More than half of the interviewees scored zero in HIV/AIDS knowledge. CONCLUSION: Factors predisposing spread of HIV infection were common in the local young men. It is recommended that intervention be implemented as soon as possible to prevent HIV infection and AIDS.

Acquired Immunodeficiency Syndrome↗

PubMed1998

The effect of bu shen sheng xue fang on beta-thalassemia at gene level.

Isoelectrofocusing electrophoresis, PCR-SSCP analysis with DNA direct sequencing and RT-PCR were used to analyze the constituents of hemoglobin, determine the pattern of globin gene mutation, and detect its mRNA transcription extent. The results indicated that Bu Shen Sheng Xue Fang (BSSXF) significantly increased the contents of hemoglobin (Hb) and fetal hemoglobin (HbF), and the chain ratio in patients with beta-thalassemia. The drug is markedly effective in heterozygous, but not effective in homozygous or genetic compound patients. It was suggested that the beta-globin gene defects were compensated by elevating the gamma/beta + gamma ratio, promoting the transcription and expression of gamma-globin gene in synthesizing HbF.

Adolescent↗

PubMed1998

[A new burn wound covering-fibroin membrane].

OBJECTIVE: This study was aimed at determining the physical and biological properties of fibroin membrane and evaluating its clinical effects. METHODS: 1. The physical and biological properties of fibroin membrane and partial thickness porcine skin were determined with various instruments. The determinations included water ratio, tensile strength, flexibility, water permeability, adhesive force and so on. 2. CLINICAL OBSERVATION: Two wounds with same depth in the same patient were selected. One was covered by fibroin membrane. The other one was treated with 1% SD-Ag cream. The changes in these wounds were observed and compared. RESULTS: This membrane had nearly same physical and biological properties compared with partial thickness porcine skin. It had no toxicity, irritation, and antigenicity. It possessed certain amount of water permeability and could adhere to the wound. Because of its good transparency, any change in underlying wound could be directly observed. It was helpful not only in local therapy but also in study of wound healing. CLINICAL OBSERVATIONs showed that this membrane had good protecting effect to wound. Its application could obviously relieve pain of wound and the healing time was 3-5 days ahead than that of the control wound. CONCLUSION: This membrane was an ideal wound covering and was worth being popularized.

Adolescent↗

PubMed1998

[Effects of monocyte-derived endothelin on acute cerebral infarction].

To investigate the mechanism that monocytes participate in ischemic brain injury, endothelin (ET) levels in plasma, supernatants of cultured monocytes in vitro and those pretreated by dexamethason (DXM) were assayed by radioimmunoassay in 31 patients with acute cerebral infarction and 16 patients with hypertension (served as control). Compared with the control group, the ET levels in supernatants of cultured monocytes increased and positively related with those in plasma and degree of neurological damage in the acute cerebral infarction group, while the ET levels in supernatants of cultured monocytes pretreated by DXM decreased. This suggests that intensifying the synthesis and release ET may be one of the mechanisms for the involvement of monocytes in the pathologic process of ischemic brain injury during acute cerebral infarction. DXM can improve this process by inhibition of producing monocyte-derived ET.

Adult↗

PubMed1998

[Study on the clinical diagnostic values of MCV and RDW to homolytic anemia].

In this study, the mean corpuscula volume (MCV) and the red blood cell distribution width (RDW) were measured in 21 patients with hemolytic anemia, 35 patients with non-hemolytic anemia, and 100 healthy subjects were in the control group. The result revealed that the changes of MCV and RDW in hemolytic anemia and the other proliferative anemia were special. As diagnostic criterion of HA, MCV and RDW showed high-sensitivity and specificity. It is useful for screening HA patients.

Adult↗

PubMed1998

[Simultaneous assay of Ca(2+)-ATPase and Na+, K(+)-ATPase activities of osteoblast rat by malachite green colorimetic method].

The aim of this study was to find a method to measure simultaneously the activities of Ca(2+)-ATPase and Na+, K(+)-ATPase of rat osteoblast membrane. In this test, Ca(2+)-ATPase and Na+, K(+)-ATPase released inorganic phosphate (Pi) from ATP, and Pi was determined by colorimetric method using malachite green dye to show ATPase activities. Ca2+ concentration and osteoblast culture generation were important factors affecting ATPase activities. Ca2+ could elevate membrane ATPase activity. When Ca2+ concentration reached 40 mumol/L, ATPase activities were improved. Ca(2+)-ATPase activity decreased with the increase of osteoblast culture generation. Ca(2+)-ATPase activity was lower than Na+, K(+)-ATPase activity in osteoblast membrane. This method is simple, sensitive and reliable.

Animals↗

PubMed1998

[Urokinase-type plasminogen activator (uPA), uPA receptor (uPA-R) and inhibitors (PA I -1) expression in hepatocellular carcinoma in relation to cancer invasion/metastasis and prognosis].

OBJECTIVE: To study the relevance of uPA, uPA-R and PA I -1 to hepatocellular cancer (HCC). METHODS: The expression at protein level for uPA, uPA-R and PA I -1 was examined in 48 cases of HCC and 12 cases of benign tumors of the liver (as control) immunohistochemically. RESULTS: When compared to HCC-adjacent normal liver tissue and the control, positive rates of immune staining for uPA, uPA-R and PA I -1 on cell membrane were significantly higher in HCC cells (P < 0.05). Positive staining of uPA and uPA-R was seen in 16 of 22 and 19 of 22 cases of HCC with invasion, respectively (P < 0.01 and < 0.001). In 8 of 8 cases with cancer emboli, and in 6 of 6 cases with lymph node metastasis was the expression of uPA-R positive. Compared with 2 of 17 cases without recurrence, uPA-R was positive in 15 of 17 recurrent cases (P < 0.01). In 36 cases who survived, 17 was positive for uPA-R and 15 for PA I -1, while in 12 cases who died 2 years after surgery, 12 and 9 cases were positive for uPA-R and PA I -1, respectively (P < 0.01 and < 0.05). In 15 cases positive for all three parameters, 11 had cancer invasion and 7 died in 2 years, while in the controls with negative staining 2 had invasion and none died in 2 years (P < 0.05). CONCLUSION: Expression of uPA, uPA-R and PA I -1 is increased in HCC, and uPA and uPA-R may contribute significantly to HCC invasion and metastasis. uPA-R and PA I -1 are associated with poor prognosis.

Blood Proteins↗

PubMed1998

[Diagnosis and treatment of skull base metastasis].

OBJECTIVE: To study the diagnosis and surgical treatment of skull base metastases. METHODS: Clinical and radiological features, operative technique and postoperative complications of 15 cases of skull base metastases were discussed. RESULTS: Total resection was achieved in 13 cases, and subtotal resection in 2. 7 tumors were located in the anterior skull base. The main complication was CSF leakage. CONCLUSION: The preoperative diagnosis of skull base metastases is difficult, radical resection is effective, and postoperative complications are not uncommon.

Adenocarcinoma↗

PubMed1998

[Clinical analysis of 15 cases of jaundice type intrahepatic cholestasis in pregnancy (ICP)].

We have analysed 15 cases of jaundice type ICP (JICP). The result showed that the incidence of JICP was 12.7 percent in ICP patients while the rectified perinatal baby mortality was 12.7 percent in ICP patients while the rectified perinatal baby mortality was 26.7%. The main clinical features were early and severe jaundice. The average levels of the total bilirubin and direct bilirubin were 123.32 +/- 86.9 mumol.L-1 and 66.77 +/- 49.7 mumol.L-1, respectively. They were significantly higher than those of the common types (P < 0.01). The level of blood biliary acid increased obviously. The morbidity of JICP in the perinatal babies and postpartal hemorrhage in the mothers were increased. It is considered that: 1. The routine DIC examination should be taken and massive therapy of vitamin K should be given to these patients. 2. The proper delivery time is the 36-37th week gestation. 3. We should choose in principle the vaginal delivery in these patients. In the severe patients the elective caesarean section is the first choice and operative vaginal delivery is undesirable.

Adult↗

PubMed1998

[The influence of Kupffer cells on experimental hepatocarcinogenesis].

OBJECTIVE: In order to explore the influence of Kupffer cells on experimental hepatocarcinogenesis. METHODS: A comparative study on the expression of proliferating cell nuclear antigen (PCNA), epidermal growth factor (EGF), ras P21, p53 protein and c-myc gene by means of immunohistochemistry or in situ hybridization during the diethylnitrosamine (DENA)-induced hepatocarcinogenesis performed in rats with and without pretreatment with gadolinium chloride (GC) which might effectively block the activity of Kupffer cells. RESULTS: There was no marked difference in the expression of PCNA and EGF in the liver tissue between the above two groups animals. The positive rate of ras P21 was markedly higher in the GC + DENA group than in the DENA group. The positive rate of p53 protein in GC + DENA group was slightly higher than that of the DENA group, however, the appearance of expression was markedly earlier in the former group (in the 11th and the 19th week respectively). The expression intensity of c-myc gene was markedly higher in GC + DENA group that in DENA group. CONCLUSIONS: The results suggest that Kupffer cells can reduce hepatotoxicity induced by chemical carcinogen, and Kupffer cells may play an inhibitory effect on the process of hepatocarcinogenesis.

Animals↗

PubMed1998

Avascular necrosis of the femoral head: MR imaging with radiological and histological correlation.

OBJECTIVE: To assess the value of MR in the diagnosis of avascular necrosis (AVN) of the femoral head. METHODS: MR images in 34 consecutive patients (26 men and 8 women) with AVN (57 hips) were reviewed. All lesions were confirmed by radiographic, radionuclide, computed tomographic, and/or histologic examination. Eleven specimens were obtained after total replacement of the hip. Four hips underwent biopsy. All MR images were obtained using a 0.35 T superconductive imaging unit with SE sequence. Specimens were cut coronally into 5 mm thick section and radiographs were obtained. RESULTS: There were four types of MR patterns of AVN. Type one appeared liner or patchy low signal area in the superoanterior portion of the femoral head. In type two, a band or ring of low signal intensity was found surrounding a central area of high signal intensity on T1WI and intermediate signal intensity on T2WI. The low signal band or ring consisted of thickened trabecular bone, mesenchymal and fibrous tissue, and amorphous acidophilic cellular debris. The central zones within the ring were composed of necrotic bone and marrow that had not been reached by the repair process. In type three, the focal subchondral region showed intermediate signal intensity on T1WI and high signal on T2WI surrounded by a low signal ring. The low signal ring consisted of thickened trabecular bone and little mesenchymal tissue. The central area was composed of mesenchymal tissue rich in capillaries and cystic necrotic zones. In type four, the signal intensity of femoral head was inhomogeneous on both T1WI and T2WI. There were low signal bands in the femoral neck surrounding the necrotic zone. Only limited areas of some lesions had signal intensity isointense with fat on T1WI and T2WI. The inhomogeneous area of low signal intensity consisted of a mixture of necrotic bone and marrow, amorphous cellular debris. The first type of MR pattern corresponded to the early stage of radiograph, and the third type of MR pattern to stage 5. The second and fourth type of MR patterns correlated less with the radiographic stage. CONCLUSIONS: MR imaging plays an important role in the diagnosis of AVN of femoral head especially in the early detection of AVN. The MR patterns of AVN is not correlated with radiographic stages exactly.

Female↗

PubMed1998

Protective effect of recombinant human augmenter of liver regeneration on CCl4-induced hepatitis in mice.

OBJECTIVE: To observe the anti-injury role of recombinant human augmenter of liver regeneration. METHODS: To establish liver injury models induced by CCl4 in vivo and in vitro, cell survival rates and LDH release rates served as observing index in experiments in vitro. Survival rates of liver failure animals, serum concentration of ALT, LDH, DNA and pathological examination were selected as parameters in experiment in vivo. RESULTS: rhALR could increase the survival rates and decrease the LDH release rates of injured hepatocytes in vitro. rhALR could also increase the survival rates of liver failure animal, promote hepatocyte proliferation and decrease the serum level of ALT and LDH in vivo. CONCLUSION: ALR is an important stimulator for liver regeneration and may play important role in liver damage repair.

Animals↗

PubMed1998

[Prophylactic and therapeutic effects of beclomethasone inhalation on bronchial hyperresponsiveness and asthma: a randomized, double-blind, parallel-group controlled trial].

OBJECTIVE: To better understand the effects of corticosteroid inhalation on asthma and asymptomatic bronchial hyperresponsiveness (BHR). METHODS: A double blind, randomized study was conducted to compare the effects of beclomethasone dry powder (BDP, 600 micrograms/day) inhalation with placebo on BHR and asthmatic symptoms in 59 students (12-18 yrs) for one year. RESULTS: After one year of treatment, lgPD20-FEV1 increased significantly in asthmatics in the BDP group (0.385 +/- 0.424 vs 1.187 +/- 0.603 mumol histamine). Thirty percent of asthmatics in BDP group and 86% in the control group developed symptoms in this year (P = 0.076). There was no significant difference in lgPD20-FEV1 between the BDP and the control group in asymptomatic BHR students. However, none in the BDP group of asymptomatic BHR students developed asthmatic symptoms compared with 3 cases (15%) in control group. The accumulative symptom score showed significant difference between the BDP group and the control group in asymptomatic BHR students (1.50 +/- 2.54 vs 5.58 +/- 6.22, P < 0.01). CONCLUSION: The results suggested that BDP could significantly relieve the severity of BHR and symptoms in asthmatics, and could have some prophylactic effects on the development of asthma in those with asymptomatic BHR.

Administration, Inhalation↗