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Biomedical subjects

Z H Wu

Publications and source records attributed to Z H Wu.

At least 19 recordsLinked to original sources
PubMed2007

Biocompatibility of electrophoretical deposition of nanostructured hydroxyapatite coating on roughen titanium surface: in vitro evaluation using mesenchymal stem cells.

A nano hydroxyapatite (HAp) layer was coated on a roughen titanium surface by means of electrophoretic deposition with an acetic anhydride solvent system. The objectives of this current study are to investigate whether nano-HAp can improve mechanical strength at a lower sintering temperature and biocompatibility. Densification temperature was lowered from usual 1000 to 800 degrees C. The coating interfacial bonding strength, phase purity, microstructure, and biocompatibility were investigated. Degradation of HA phase was not detected in XRD. A porous TiO2 layer acts as a gradient coating layer with an intermediate thermal expansion coefficient between hydroxyapatite and titanium that reduces the thermal stress. From SEM image, the coating does not contain any crack. Mesenchymal stem cell (MSC) is the progenitor cell for various tissues in mature animals, which can improve integration of bone tissue into implant. In this in vitro study, rabbit MSCs culture indicated that the HAp/Ti nanocomposite biomaterial had good biocompatibility and bioactivity. Around materials and on its surface cell grew well with good morphology. Proliferation of the MSCs on the nano-HAp coating was higher than its micron counterpart in XTT assay. These properties show potential for the orthopaedic and dental applications.

Animals↗
PubMed2006

Usefulness of diffusion/perfusion-weighted MRI in patients with non-enhancing supratentorial brain gliomas: a valuable tool to predict tumour grading?

22 patients with non-enhancing supratentorial gliomas on contrast-enhanced MRI underwent both diffusion- and perfusion-weighted MRI (DWI/PWI) before surgical resection. 14 low-grade gliomas (WHO Grade I and II) and 8 anaplastic gliomas were verified histologically. Both apparent diffusion coefficient (ADC) values and relative cerebral blood volume (rCBV) ratios were calculated on the solid portion of the tumour, on peritumoural area, as well as on the contralateral normal white matter, respectively. The results showed that lower ADC values were present in the solid portions of anaplastic gliomas, but not in low grade (p < 0.01). All ADC values in peritumoural regions of tumours were decreased compared with the contralateral normal white matter. However, there was no significant difference between anaplastic gliomas and low-grade gliomas. Meanwhile, higher rCBV ratios were present in both solid portions and peritumoural regions of anaplastic gliomas, but not in low grade gliomas (p < 0.01). In conclusion, non-enhancing brain gliomas with lower ADC values in the solid portions and higher rCBV ratios in both solid portions and peritumoural regions of tumours are significantly correlated with anaplasia. Therefore, DWI and PWI should be integrated in the diagnostic work-up of non-enhancing gliomas in order to predict grading.

Adult↗
PubMed2006

Nano-structural bioactive gradient coating fabricated by computer controlled plasma-spraying technology.

The poor mechanical property of hydroxyapatite was the major problem for load bearing and implant coating in clinical applications. To overcome this weakness, a bioactive gradient coating with a special design composition of hydroxyapatite (HA), ZrO2, Ti, bioglass was developed. This 120 microm coating with an upper layer of 30-50 microm porous HA produced by computer controlled plasma spraying which maintained energy level of the plasma which ensure proper melting of powder. The crystal size of the coating was 18.6-26.2 nm. Transformation of t-ZrO2 to m-ZrO2 reduced the thermal stress that weakened the coating and lowered down interfacial strength of the coating and metal substrate. Thermal stress of sprayed coating was 16.4 MPa which was much smaller than the sample without thermal treatment of 67.1 MPa. Interfacial strength between the coating and metal substrate was 53 MPa which is much higher than conventional Hydroxyapatite coating. Based on XRD analysis crystallinity of HA approached 98%. Therefore, high temperature treatment improved long term stability of the coating through improved crystallinity of hydroxyapatite and reduced other impure calcium phosphate phase.

Aluminum Oxide↗
PubMed2001

Prevalence and associated factors of cancer screening: why are so many older Mexican American women never screened?

OBJECTIVES: The aim of this study was to identify patterns of mammogram and Papanicolaou (Pap) screenings among Mexican American women ages 67 and over. METHODS: Data on 1,403 Mexican American women from the Hispanic Established Population for the Epidemiological Study of the Elderly, a cohort study of community-dwelling Mexican Americans ages 65 years or over from the southwestern United States, were analyzed. RESULTS: Mexican American women age 75 or older were less likely to ever have had breast or cervical screening than women ages 67 to 74, even controlling for sociodemographic, cultural, and selected health factors. Overall, fewer medical conditions and never having had a hysterectomy were found to be associated with a decreased chance of ever having had a mammogram or a Pap test. Women who lacked insurance coverage and had fewer doctor visits were less likely to ever have had a mammogram, whereas women with low education, low acculturation, and lower cognitive status scores were less likely to ever have had a Pap test. CONCLUSIONS: If these results withstand more detailed studies (e.g., with the addition of important variables such as awareness), better communication with health professional doctors and improvement of access to heath care services should increase rates of both mammogram and Pap screenings.

Acculturation↗
PubMed2001

HIV Seroprevalence among newly incarcerated inmates in the Texas correctional system.

PURPOSE: The seroprevalence of HIV infection was examined among a sample of incoming inmates in the Texas Department of Criminal Justice prison system. Rates were compared across sociodemographic factors and three types of prison facilities: substance abuse felony punishment units (SAFPs), state jails, and prisons. METHODS: The study sample consisted of 4386 incoming inmates incarcerated for any duration, dating from November 1, 1998, to May 31, 1999. RESULTS: Among males, inmates entering state jails had a higher HIV infection rate (3.7%) than either inmates entering prisons (1.9%) or those entering SAFPs (0.5%). Among females, inmates entering prisons had a higher rate of infection (9.3%) than those entering state jails (2.5%) or SAFPs (4.5%). CONCLUSIONS: Although a number of blinded HIV seroprevalence studies have been conducted in U.S. prison systems, scarce information is currently available on HIV infection rates in alternative correctional facilities. The present study shows that HIV seropositivity varied substantially according to race, gender, and prison facility type. Given the shorter incarceration periods for inmates held in alternative facilities, understanding how infection rates vary according to type of incarceration facility holds particular public health relevance.

Adolescent↗
PubMed2001

The influence of patients' concerns on surgeons' recommendations for early breast cancer.

This paper examines whether an older patient's concerns about surgical treatment of breast cancer--such as fear of dying or about losing a breast--affect the treatment recommendations by their surgeons. A sample of 137 older women diagnosed with early stage breast cancer between 1994 and 1996 were interviewed within 2 months of diagnosis to determine demographic characteristics, their attitudes about breast cancer treatments, and which surgical treatment their surgeon initially recommended. The treatment preferences of the 35 surgeons treating these women were ascertained by asking them what treatment they would usually recommend to a hypothetical 75-year-old woman with early stage breast cancer. Patients who reported their feelings about losing a breast as 'very important' were less likely to be recommended mastectomy (Odds Ratio (OR) = 0.39; 95% (Confidence Interval) CI 0.16, 0.94), while patients who reported fear of dying from breast cancer as 'very important' were more likely to be recommended mastectomy (OR = 4.60; 95% CI 1.94, 11.59), after adjusting for surgeons' age and the surgeons' treatment preference when presented with a hypothetical patient. It is concluded that surgeons integrate patients' attitudes and concerns into their treatment recommendations.

Aged↗
PubMed2001

Axillary osmidrosis treated by partial removal of the skin and subcutaneous tissue en bloc and apocrine gland subcision.

BACKGROUND: Axillary osmidrosis can be treated with many methods, but local surgery is the treatment of choice. METHODS: Forty-three patients (32 females and 11 males, average age 20.3 years) were treated by partial removal of the skin and subcutaneous tissue en bloc and follicular clipping of the adjacent area. All operations were performed with local anesthesia in an outpatient setting. RESULTS: Follow-up ranged from 2 to 47 months (mean: 13.4 months). Forty-one patients (95%) had good results, two (5%) were fair, and none were poor. No recurrences were seen. The wound complication rate was 3.5% for axillae and 7% for patients. There were no scar contractures or limitations of arm abduction. CONCLUSION: This combined surgical method can eliminate malodor and has a low wound complication and recurrence rate. Though the transient and conspicuous scar is the chief drawback of this method, it is a simple, safe, effective and inexpensive method for treating axillary osmidrosis.

Adolescent↗
PubMed2001

Effects of growth hormone (rhGH) and glutamine supplemented parenteral nutrition on intestinal adaptation in short bowel rats.

This study was performed to compare the effects of recombinant human growth hormone (rhGH), glutamine (Gln) and simultaneous treatment with rhGH and Gln in rats subjected to 75% intestinal resection and maintained with parenteral nutrition (PN) for 6 days. Morphological changes including mucosal thickness, villus height, crypt depths and villus surface area of the residue jejunum were measured under a light microscope; expression of PCNA as an index of cell proliferation and apoptotic cells were observed using immunohistochemical staining; Ileal IGF-1 mRNA was determined by Northern blot analysis. The morphological parameters of the jejunal mucosa in rats treated with PN alone were only about 52-62% of those in reference group (P<0.01), this atrophy of the jejunal mucosa was accompanied by a 2.5-fold decrease in absolute counts of PCNA and a 10-fold increase in apoptotic index (P<0.01), IGF-1 mRNA transcript in residue ileum was decreased significantly (P<0.01). However, with rhGH or Gln, the mucosal architecture was improved significantly and was further improved when rhGH and Gln were given together, the morphological values in rats treated with Gln+rhGH was 79% higher than those with PN alone, and was associated with a 2-fold increase in PCNA counts and a 4-fold decrease in apoptotic index (P<0.01), IGF-1 mRNA expression was 78% higher than those with PN alone (P<0.01). We conclude that rhGH and Gln have synergistic effects on adaptation of the intestinal remnant in parenterally fed, short-bowel rats. The underlying mechanisms are associated with increased proliferation and decreased apoptosis in the intestinal epithelial cells. Local intestinal production of IGF-1 plays an important role in adaptation of the small intestine. Our findings support the concept that specific gut-trophic nutrients and growth factors may be combined to enhance the intestinal adaptation.

Adaptation, Biological↗
PubMed2001

Modulation of postoperative immune and inflammatory response by immune-enhancing enteral diet in gastrointestinal cancer patients.

AIM: To evaluate if the administration of an enteral diet supplemented with glutamine, arginine and omega-3-fatty acids modulates inflammatory and immune responses after surgery. METHODS: A prospective randomized double-blind, clinical trial was performed. Forty-eight patients with gastrointestinal cancer were randomized into two groups, one group was given an isocaloric and isonitrogenous standard diet and the other was fed with the supplemented diet with glutamine, arginine and omega-3-fatty acids. Feedings were started within 48 hours after operation, and continued until day 8. All variables were measured before operation and on postoperative day 1 and 8. Immune responses were determined by phagocytosis ability, respiratory burst of polymorphonuclear cells, total lymphocytes lymphocyte subsets, nitric oxide, cytokines concentration, and inflammatory responses by plasma levels of C-reactive protein, prostaglandin E2 level. RESULTS: Tolerance of both formula diets was excellent. There were significant differences in the immunological and inflammatory responses between the two groups. In supplemented group, phagocytosis and respiratory burst after surgery was higher and C-reactive protein level was lower (P<0.01) than in the standard group. The supplemented group had higher levels of nitric oxide, total lymphocytes, T lymphocytes, T-helper cells, and NK cells. Postoperative levels of IL-6 and TNF-alpha were lower in the supplemented group (P <0.05). CONCLUSION: It was clearly established in this trial that early postoperative enteral feeding is safe in patients who have undergone major operations for gastrointestinal cancer. Supplementation of enteral nutrition with glutamine, arginine, and omega-3-fatty acids positively modulated postsurgical immunosuppressive and inflammatory responses.

Adult↗
PubMed2001

[Non-NMDA receptors are involved in the modulation of discharge activity of biphasic expiratory neurons and inspiratory neurons].

Experiments were performed on in vitro brainstem slice preparations from neonatal rats that retain respiratory network activity. Extracellular recordings were made from 99 neuronal units, respiratory-related or non-respiratory related with rhythmical activity, out of which there were 7 biphasic expiratory and 11 inspiratory ones. Possible roles of non-NMDA receptors in reciprocal excitation among the biphasic expiratory neurons and in excitatory synaptic inputs to inspiratory neurons were investigated by administration of non-NMDA receptor agonist KA and its antagonist DNQX in the perfusion solution. Bath application of non-NMDA receptor agonist KA increased the peak frequency of both biphasic expiratory and inspiratory neuronal discharges, and increased the discharge frequency of the biphasic expiratory neurons and the inspiratory neurons in the middle phase, while the frequency of discharge in the early and late phases were less affected. All of these effects were blocked by addition of the non-NMDA receptor antagonist DNQX, suggesting the involvement of non-NMDA receptors.

Animals↗
PubMed2001

Older Mexican-American women and cancer screening: progress toward targets for healthy people 2000.

BACKGROUND: Published information about cancer screening in older Mexican-American women is scarce. This study reported the patterns of mammogram and Pap test use among older Mexican-American women. The patterns and associated factors were examined and compared with Healthy People 2000 targets. METHODS: Data were obtained from the Hispanic Established Population for the Epidemiological Study of the Elderly, the largest representative survey of community-dwelling Mexican Americans aged 67 years or over, from the southwestern United States. RESULTS: Among older Mexican-American women, 68.3% reported ever having a mammogram, and 41.2% reported having a mammogram in the last two years; 64.0% reported ever having a Pap test, with 43.6% reported having a Pap test in the last three years. CONCLUSIONS: The data for older Mexican-American women demonstrated that they approached the targets for breast cancer screening, but not for Pap test use.

Aged↗
PubMed2001

[A comparative study on cytochemistry between spring and fall peanut seeds].

A comparative study was conducted on cytochemistry of spring and fall crop seeds in peanut cultivars Quanhua No. 10 and Shanyou 71 respectively. Lipids, protein, and polysaccharides in cells of axis and coteledon were simultaneously shown in the Epon812 buried section by means of cytochemistry, and their morphology, quantity and distribution were compared. Embryo cells of spring crop seed develop fully with big cell more vivid contrasting texture and more regularly disposed organelle, but the counterpart cells in fall crop seeds were not as much mature and their organelle arrangement appeared somewhat irregular. In cotyledon storage cells, there were also some difference between spring crop seed and fall crop seed. Cells of spring crop seeds were full of reserves, with more lipid and protein bodies that were closely ranged and extruded with each other. However, the cell structure in fall crop seeds was more loosely arranged, vacuoles had not been filled with protein, but starch grains accumulated more. Therefore, it was shown clearly that spring crop seeds have some advantages over fall crop seeds on production application. Moreover, some cytochemical techniques for demonstration of lipid, polysaccharide and protein in thick resin section and the stain protection were discussed in the paper.

Arachis↗
PubMed2001

[Preliminary investigation on the pathogeny, diagnosis and treatment of chondromalacia patella].

This paper presents the preliminary investigation on chondromalacia patella at our department in recent years. A random cluster sampling survey covering 2743 normal persons was carried out. The prevalence rate is 36.2%. It was found that, applying transmission electron microscope and immunohistochemical methods on to cartilage tissues of the abnormal region, articular cartilage necrosis was in direct proportion with the abnormal pressure, while the restoration capability of local chondrocytes was in inverse proportion with pathological changes and the pressure. The chondromalacia patella was produced by repeated abnormal stress acting on the cartilage. The stress derived from the uncongruency and the decreasing in the contact area of patellofemoral joint when the subluxation or tilt of patellae was caused by the abnormal anatomical and biomechanical relationship. The initial lesion was at the matrix of cartilage, the collagen network was disrupted, then proteoglycan was lost. The microenvironment of chondrocytes was changed with degradation of matrix. So the chondrocytes became degenerative and necrosis from superficial to deep layer, then feed back the matrix again. Finally, the total cartilage layer might disappear, and the bone under cartilage might proliferate. At late stage, the cartilage was completely destroyed and had no self-restorative ability. Therefore, early diagnosis and treatment are necessary. It is highly suggested axis radiograph of the knee with the tibiae tuberositas localization are helpful to early diagnosis. Furthermore, JKY-Muscle Rehabilitation Instrument is invented for non-operative therapy. It enhances muscle power by selective training of the vastus medialis muscle using electrical stimulator to relieve pain and correct subluxation of patella with 90% efficiency (63% of excellent-effective rate). In late stage, patellofemoral replacement is recommended. The excellent-effective rate is 86.3%.

Arthroplasty, Replacement, Knee↗
PubMed2000

Mitigation of endotoxin-induced acute lung injury in ventilated rabbits by surfactant and inhaled nitric oxide.

OBJECTIVE: To evaluate the efficacy of surfactant and inhaled nitric oxide (iNO) in endotoxin-induced acute lung injury (ALI). DESIGN: Prospective, randomised, controlled experimental study. SETTING: A medical university hospital research laboratory. INTERVENTION: Twenty-nine adult rabbits (2.4-3.4 kg) were given two doses of intravenous endotoxin (Escherichia coli) (0.01 mg/kg and, 12 h later, 0.1 mg/kg), and then subjected to mechanical ventilation. After 8 h these animals were allocated to four treatment groups: (1) control, (2) iNO at 20 ppm (NO), (3) surfactant at 100 mg/kg (Surf) and (4) both surfactant and iNO as in groups 2 and 3 (SNO), and ventilated for a further 6 h followed by broncho-alveolar lavage (BAL), analysis of surfactant contents in BAL fluid and histological examination of the lungs. MEASUREMENTS AND RESULTS: All the animals had developed ALI with respiratory failure 8 h after the second dose of endotoxin as evidenced by a decrease of PaO2/FIO2 from 520 +/- 30 to 395 +/- 19 mmHg and dynamic compliance (Cdyn) from 1.20 +/- 0.11 to 0.73 +/- 0.05 ml/ cmH2O x kg, and an increase of intrapulmonary shunting (Qs/Qt) from 7.5 +/- 0.8% to 12.9 +/- 1.0% (all measurements p < 0.01 versus baseline). In the SNO group, values for PaO2/FIO2, Cdyn and Qs/Qt after 6 h were 301 +/- 15 mmHg, 0.67 +/- 0.05 ml/cmH2O x kg and 16.5 +/- 0.8%, compared to 224 +/- 26 mmHg, 0.53 +/- 0.04 ml/ cmH2O x kg and 24.1 +/- 2.0%, respectively, in the control group (all measurements p < 0.01). Both Surf and NO groups showed intermediate levels of these parameters. In both Surf and SNO groups, the minimum surface tension of BAL fluid was lower, and the content of disaturated phosphatidylcholine/total protein higher, than in the control and NO groups (p < 0.01). Histological features of lung injury were less prominent and wet/dry lung weight ratio lower in the NO, Surf and SNO groups. Decreased surfactant protein A (SP-A) and its mRNA expression were found in all endotoxin-exposed groups, but the SP-A content of the SNO group was moderately improved in comparison to the control group. Surfactant aggregate size was not affected. CONCLUSION: Early application of surfactant and iNO moderately mitigated ALI as reflected by improvement of lung mechanics, pulmonary perfusion and morphology.

Administration, Inhalation↗
PubMed2000

Social contact, socioeconomic status, and the health status of older Malaysians.

We tested the applicability of the stress buffering hypothesis in a developing country setting with data from the Senior Sample of the Malaysian Family Life Survey-2. Using ordered logistic regression methods, we examined whether having daily contact with adult children moderates the effect of low socioeconomic status (SES; conceptualized as a chronic stressor) on self-assessed health status. We found that low SES is associated with poorer health for all three ethnic groups--Malay, Chinese, and Indian. Further, for Malays and Chinese, we found that the negative effects of low SES on health tend to be stronger for older people with less frequent contact with adult children than for those who have daily contact. These results provide general support for the buffering model and suggest that, as found in developed countries, active intergenerational relationships in developing country settings may have protective effects on the health of older people experiencing chronic stressors.

Adult↗
PubMed2000

Dysfunction of microvascular endothelial cells induced by tumor necrosis factor (TNFalpha): cellular and molecular mechanism.

The dysfunction of rat pulmonary microvascular endothelial cells (RPMVEC) induced by tumor necrosis factor alpha (TNFalpha) was investigated in cell culture. The TNFalpha concentrations added into culture were 1000-5000 u/ml. The study was done at different steps as follows: (1) cell proliferation dynamic, (2) coagulation and anti-coagulation, (3) adhesive molecule, (4) nitric oxide (NO), (5) oncogens, and (6) apoptosis. It was concluded that attention should be paid to the metabolic disorder and dysfunction of RPMVEC induced by TNFalpha which can not be found easily according to the morphological changes. This might be the common pathway in the pathogenesis of some diseases related to TNFalpha.

Animals↗
PubMed1999

[Activation of G protein on the membrane of TCS-sensitive cells].

Trichosanthin (TCS), a Type I Ribosome Inactivating Protein isolated from the root tuber of Trichosanthes Kirilowii M. has various biological activities including abortion induction, anti-tumor and anti-HIV. The mechanism of TCS specifically killing sensitive cells has not been studied clearly. In this study, we initially found that there exists TCS-affinity molecule on Syncytiotrophoblast cells and Jar cells. Furthermore, by [35S]GTP gamma S Binding Assay, we find that TCS can activate G protein on the membrane of TCS-sensitive cells. These results indicate that on the membrane of TCS-sensitive cells exists TCS-specific receptor.

Cell Membrane↗