Biomedical subjects

Z Q Hu

Publications and source records attributed to Z Q Hu.

At least 19 recordsLinked to original sources

PubMed2005

Penis reconstruction using three different operative methods.

To identify the relative success rates, including aesthetic success, of three penis reconstruction techniques, we reviewed 44 cases of penis reconstruction carried out over the past 12 years. The three operative methods we surveyed involved: lower abdominal pedicled fascia flaps; paraumbilical island flaps; and free forearm flaps. Reconstructions survived in only half of the patients receiving lower abdominal pedicled fascia flaps, but 100% success rates were obtained with paraumbilical island flaps and free forearm flaps. The paraumbilical island flap is safe in terms of its blood supply, and the operative procedure is relatively simple in that it does not require microsurgery. Although, the flap is thicker than the forearm skin flap, its shape is satisfactory in slim patients; furthermore, it can be defatted secondarily. The free forearm skin flap provides the best shape, but skilled microsurgery is necessary to carry out the procedure, and damage is likely to the forearm. In conclusion, the best methods to repair defects in the penis in our experience are the paraumbilical island flap and free forearm flap. Lower abdominal pedicled fascia flaps are unsuitable for penile reconstruction and should be used less often.

Abdomen↗

PubMed2005

Laparoscopic-assisted colon and rectal surgery - lessons learnt from early experience.

INTRODUCTION: Current evidence shows that laparoscopic bowel surgery is associated with a lower incidence of postoperative ileus, lower postoperative pulmonary and wound complication rates, shorter hospital stays and a quicker return to activity than open surgery. This paper aims to report our early experience with laparoscopic-assisted colorectal procedures in our Centre for Advanced Laparoscopic Surgery and the important lessons we have learnt from this. MATERIALS AND METHODS: All laparoscopic-assisted colon and rectal surgical (LAC) procedures performed between January 2000 and December 2003 were reviewed. Clinical and operative records of these patients were reviewed. Data retrieved included patient demographics, selected intraoperative parameters, and postoperative outcomes. In order to provide a comparable reference, an equal number of matched open procedures over the same period were accrued and similarly analysed. All patients were managed on a standard carepath. All data were entered into a database and analysed using a statistical software package. RESULTS: Forty-two laparoscopicassisted colorectal procedures were performed from June 2000 to December 2003. A similar number of diagnosis-matched patients with open colorectal procedures were used as comparison. The diagnoses included cancer (68.5% versus 73.8%), diverticulosis (5.7% versus 9.5%) and polyps (14.3% versus 9.5%). Seven were converted to open surgery because of bleeding, adhesions and locally advanced disease. Laparoscopic-assisted procedures performed included 1 right hemicolectomy, 5 left hemicolectomies, 9 anterior resections, 1 abdominal-perineal resection, 3 sigmoid colectomies, 11 colostomies and 1 Hartmann's procedure. Mean perioperative time (146 min versus 125 min, P = 0.173) was comparatively longer. Mean duration for analgesic requirement (2.25 days versus 2.64 days, P = 0.05), mean length of stay (5.31 days versus 9.07 days, P < 0.05), mean time to commencement of diet (2.91 days versus 4.05 days, P < 0.001) and mean time to first bowel movement (2.57 days versus 4.10 days, P < 0.001) were all comparatively shorter. General morbidity rates (17.1% versus 21.4%, P = 0.35) were lower. No local wound complications were found in our laparoscopic-assisted group. Patients who had undergone open surgery instead of the planned laparoscopic-assisted procedures fared more poorly. CONCLUSIONS: Laparoscopic-assisted colorectal procedures performed in well-selected patients are associated with shorter hospital stays, quicker return of bowel function and lower morbidity when compared to the matched open procedures. Early experience should be acquired from performing technically simple procedures in patients with benign conditions before progressing to definitive resections in those with cancer.

Adult↗

PubMed2004

Molecular dynamics study of atomic transport properties in rapidly cooling liquid copper.

Based on Mei's embedded atom model molecular dynamics simulations have been performed to investigate the rapidly cooling processes of Cu. The atomic transport property, namely the self-diffusion coefficient, is computed in the liquid state, and the results near the melting point of Cu are in good agreement with experimental data and other computational values. The atom diffusion movements during the long period of relaxation have been also studied around the solidification temperature Tc. To describe the complex microstructural evolutions during the rapidly cooling processes and the long relaxation processes, the pair correlation function and the pair analysis technique are used. It is demonstrated that the crystallization of amorphous Cu is caused by the atomic diffusion.

Journal Article↗

PubMed2003

Growth and nutrient uptake of arbuscular mycorrhizal maize in different depths of soil overlying coal fly ash.

Application of topsoil over phytotoxic mine wastes is often practised to establish perennial plant communities on minespoil areas. In China, population pressure encourages attempts to remediate such areas by growing arable crop plants, but efforts to establish agricultural crops often fail. We report an outdoor pot experiment that compared the effects of two arbuscular mycorrhizal (AM) fungi, Glomus mosseae (Nicol. and Gerd.) Gerdemann and Trappe and G. versiforme (Karsten) Berch, on the growth and nutrient uptake of maize (Zea mays L.) grown in different depths of soil layer overlying coal fly ash. Colonization by both AM fungi increased plant growth compared with non-mycorrhizal controls, with G. mosseae giving higher yields of maize than G. versiforme at the same depths of soil. Increasing soil depth led to increased plant yields. Mycorrhizal plants absorbed more nutrients than non-mycorrhizal controls, and translocated less Na to the shoots, perhaps protecting the plants from excessive Na accumulation. These preliminary results indicate that arbuscular mycorrhizas may make a substantial contribution to successful crop establishment in soils overlying areas of coal fly ash.

Biodegradation, Environmental↗

PubMed2001

Inhibition by epigallocatechin gallate (EGCg) of conjugative R plasmid transfer in Escherichia coli.

Epigallocatechin gallate (EGCg) in tea catechins blocked or significantly diminished the transfer of conjugative R plasmid between Escherichia coli C600 with plasmid R-222 (donor) and E. coli K-12 RC85 (recipient) in a dose-dependent manner. The inhibition rates of R plasmid transfer by EGCg were 42%-67% at 50-200 microg/ml, and up to 99% at 800 microg/ml. Nevertheless, EGCg, even at the concentration of 1600 microg/ml, was not sufficient to kill E. coli cells in 1 h, as confirmed by determining viable cells after incubation with various concentrations of EGCg. The result indicates that the bactericidal activity of EGCg against the two strains was not the main factor responsible for the inhibition of R plasmid transfer. This observation suggests the possibility that tea consumption may be effective in preventing R plasmid transfer in enteric bacteria.

Catechin↗

PubMed2001

Epigallocatechin gallate synergy with ampicillin/sulbactam against 28 clinical isolates of methicillin-resistant Staphylococcus aureus.

Compared with ampicillin, oxacillin, cefmetazole and imipenem, the combination of ampicillin and sulbactam at a constant ratio of 2:1 showed the greatest effect against 28 clinical isolates of methicillin-resistant Staphylococcus aureus (MRSA), but MICs of ampicillin/sulbactam were still above the resistance breakpoint. When ampicillin/sulbactam was further combined with epigallocatechin gallate (EGCg, a main constituent of tea catechins), the MIC90 of ampicillin/ sulbactam was reduced to 4 mg/L, the susceptibility breakpoint. The fractional inhibitory concentration indices were between 0.19 and 0.56 in combination with 6.25 and 25 mg/L EGCg, respectively, indicating that ampicillin/sulbactam and EGCg combination may be effective against MRSA infections.

Ampicillin↗

PubMed2001

Mechanism of synergy between epigallocatechin gallate and beta-lactams against methicillin-resistant Staphylococcus aureus.

Compared to MICs (more than 800 microg/ml) of (-)-epigallocatechin gallate (EGCg) against Escherchia coli, MICs of EGCg against methicillin-susceptible and methicillin-resistant Staphylococcus aureus (MSSA and MRSA) were 100 microg/ml or less. Furthermore, less than 25 microg EGCg per ml obviously reversed the high level resistance of MRSA to all types of tested beta-lactams, including benzylpenicillin, oxacillin, methicillin, ampicillin, and cephalexin. EGCg also induced a supersusceptibility to beta-lactams in MSSA which does not express mecA, encoding penicillin-binding protein 2' (PBP2'). The fractional inhibitory concentration (FIC) indices of the tested beta-lactams against 25 isolates of MRSA were from 0.126 to 0.625 in combination with 6.25, 12.5 or 25 microg of EGCg per ml. However, no synergism was observed between EGCg and ampicillin against E. coli. EGCg largely reduced the tolerance of MRSA and MSSA to high ionic strength and low osmotic pressure in their external atmosphere, indicating damage of the cell wall. Unlike dextran and lipopolysaccharide, peptidoglycan from S. aureus blocked both the antibacterial activity of EGCg and the synergism between EGCg and oxacillin, suggesting a direct binding of EGCg with peptidoglycan on the cell wall. EGCg showed a synergistic effect with DL-cycloserine (an inhibitor of cell wall synthesis unrelated to PBP2') but additive or indifferent effect with inhibitors of protein and nuclear acid synthesis. EGCg did not suppress either PBP2' mRNA expression or PBP2' production, as confirmed by reverse transcription-PCR and a semiquantitative PBP2' latex agglutination assay, indicating an irrelevance between the synergy and PBP2' production. In summary, both EGCg and beta-lactams directly or indirectly attack the same site, peptidoglycan on the cell wall. EGCg synergizes the activity of beta-lactams against MRSA owing to interference with the integrity of the cell wall through direct binding to peptidoglycan.

Anti-Bacterial Agents↗

PubMed2001

[Study on transplantation of anterolateral femoral skin flap with high site direct cutaneous artery].

OBJECTIVE: To study the availability of transplantation of anterolateral femoral skin flap with absence of the first branch of musculocutaneous artery. METHODS: One hundred and sixty cases of anterolateral femoral skin flap transplantation in the past 15 years were reviewed, to investigate the relationship between the outcome of the transplantation and the types, distribution, original point, diameter of blood vessels. Among the 160 cases, there were 10 cases, 6.3% in total, of skin flap transplantation with the pedicle of high site direct cutaneous femoral artery, ranging from 10 cm x 14 cm to 12 cm x 18 cm in size, applied to repair soft tissue defect. RESULTS: There were 149 cases, among the 160 cases, survived and all the 10 cases of femoral skin flap transplantation with high site anterolateral cutaneous artery survived. CONCLUSION: The femoral skin flap with high site anterolateral cutaneous artery has good blood supply, larger size available, and easier operation. When the first branch of descending anterolateral femoral artery is absent, the femoral skin flap with high site anterolateral cutaneous artery is an optimal alternative.

Adult↗

PubMed2000

[Detection of differentially expressed genes in hepatocellular carcinoma using DNA microarray].

Large scale gene expression profiles between normal hepatocytes and hepatocellular carcinomas are detected with high throughput microarray. DNA microarrays were made by spotting PCR products of 4,096 human cDNAs onto a specially treated glass slides. The probes were prepared by labelling normal tissue mRNA and cancer tissue mRNA with Cy3-dUTP and Cy5-dUTP separately through reverse transcription. The arrays were then hybridized against the cDNA probe mixture and the fluorescent signals were scanned. The obtained data were analyzed from 4 repeated experiments. There are 903 genes of which the average ratios between Cy3 signal and Cy5 signal are greater than 3.0. These genes identified through this approach are potential candidates for hepatocellular carcinoma diagnosis and therapy.

Carcinoma, Hepatocellular↗

PubMed2000

[The pathological changes of nasopharyngeal carcinoma cases treated by stereotactic radiosurgery].

OBJECTIVE: To study the pathological changes of nasopharyngeal carcinoma cases after the treatment of stereotactic radiosurgery. METHOD: 15 cases with recurrent or residual squamous cell carcinoma of nasopharynx diagnosed as T1-4 N0M0 were selected, which had undergone previous radiotherapy. The patients were treated by Gamma Knife while the isodose curve was 50% and the margin dose was 20 Gy. The nasopharynx biopsy was performed before the treatment and 1, 3, 6, 12 months after the treatment. The biopsy specimen was taken to make a pathological examination. RESULT: 1. Before the Gamma Knife treatment, carcinoma cell could be seen in the tissue; 2. 1-3 months after the treatment, cell necrosis and acute inflammation cell infiltration could be seen in the target; 3. 6-12 months after the treatment, infiltration of chronic inflammation cell, proliferation of fibrous tissue and capillary could be found in the target. CONCLUSION: This research implies that the short-term pathological changes after the treatment of stereotactic radiosurgery can be defined as two phases: The first phase occurs from 1 to 3 months after the treatment called necrosis period. The second phase occurs from 6 to 12 months after the Gamma Knife treatment named as absorption period.

Carcinoma, Squamous Cell↗

PubMed1999

Spontaneous canine mast cell tumors express tandem duplications in the proto-oncogene c-kit.

Spontaneous mast cell tumors (MCT) are the most common malignant neoplasm in the dog, representing between 7% and 21% of all canine tumors, an incidence much higher than that found in humans. These tumors often behave in an aggressive manner, metastasizing to local lymph nodes, liver, spleen, and bone marrow. The proto-oncogene c-kit is known to play a critical role in the development and function of mast cells. Point mutations in the kinase domain of c-kit leading to tyrosine phosphorylation in the absence of ligand binding have been identified in three mastocytoma lines, (P815, RBL, and HMC-1), and some human patients with various forms of mastocytosis. We now demonstrate that although c-kit derived from canine MCT did not contain the previously described activating point mutations, 5 of the 11 tumors analyzed possessed novel mutations consisting of tandem duplications involving exons 11 and 12. We also show that one such duplication, detected in a canine mastocytoma cell line, was associated with constitutive phosphorylation of c-kit protein (KIT), suggesting that these mutations may contribute to the development or progression of canine MCT.

Amino Acid Sequence↗

PubMed1997

Tumor necrosis factor-alpha- and interleukin-6-triggered mast cell development from mouse spleen cells.

We previously showed that interleukin-3 (IL-3) alone is not sufficient, although it is essential for murine mucosal-type mast cell development and that prostaglandin E (PGE) and interferon-gamma (IFN-gamma) are critical for survival or differentiation of mast cell precursors. We also confirmed that IL-4 is a key inhibitor for mast cell precursors despite being a growth factor of mast cells. In the present work, mouse spleen cells were cultured with recombinant (r) IL-1 beta, rIL-5, rIL-6, rIL-9, granulocyte-macrophage colony-stimulating factor (GM-CSF), stem cell factor (SCF), tumor transforming growth factor-beta (TGF-beta), or tumor necrosis factor-alpha (TNF-alpha) in the presence of endogenous IL-3. After 12 days of culture, mast cell development was induced by rIL-6 and rTNF-alpha, rIL-1 beta, rIL-5, rGM-CSF, rTGF-beta and even the mast cell growth factors, rIL-9 and rSCF, failed to induce mast cell development. However, unlike IL-9 and SCF, IL-6 and TNF-alpha did not promote the growth of mast cells already developed. Macrophage may be one of the responsive cells of IL-6 and TNF-alpha in the cultures, because removal of macrophages greatly reduced the mast cell development induced by the cytokines. The actions of TNF-alpha and IL-6 were inhibited by indomethacin, an inhibitor for prostaglandin synthesis, and by neutralizing anti-IFN-gamma and anti-IL-3 antibodies. rIL-4, when added at the start of the culture, also inhibited mast cell development induced by rIL-6 and rTNF-alpha. Nevertheless, neutralizing anti-IL-6 and anti-TNF-alpha antibodies did not suppress mast cell development induced by PGE and IFN-gamma. TNF-alpha and IL-6 enhanced IFN-gamma production, but suppressed IL-4 production in the cultures. Mast cell numbers induced were inversely and directly proportional to IL-4 and IFN-gamma levels, respectively. These results indicate that inflammatory mediators as triggers are important for mast cell development although they are not the mast cell growth factors.

Animals↗

PubMed1997

Erythrocyte-dependent mitogenic activity of epigallocatechin gallate on mouse splenic B cells.

We previously reported that epigallocatechin gallate (EGCg), the main constituent of tea catechins, displays mitogenic effect on mouse splenic B cells. During research into the mechanism(s), it was found that the mitogenic activity of EGCg was dependent on the presence of red blood cells (RBC). When RBC in T cell-depleted spleen cells were removed, EGCg did not enhance the proliferation of B cells and even showed toxic effect at 25-50 micrograms/ml. When mouse, rabbit or sheep RBC as well as RBC-ghosts were added into the cultures, EGCg showed the mitogenic activity at a range of 1-50 micrograms/ml. Thereafter, we preincubated RBC with EGCg at 4 degrees C for various times and then washed the RBC to remove free EGCg in the suspensions. The EGCg-preincubated RBC also enhanced B cell proliferation. As short as ten minutes was sufficient for EGCg to bind to RBC membrane. These results indicate that EGCg first attached to the membrane of RBC and then stimulated B cell proliferation. The above results suggest an important immunoregulatory function of RBC.

Animals↗

PubMed1996

Down-regulation by IL-4 and up-regulation by IFN-gamma of mast cell induction from mouse spleen cells.

While investigating an involvement of other factors aside from endogenous IL-3 and prostaglandin E (PGE) in mast cell induction from mouse splenocytes, we found that the mast cell induction was inversely proportional to IL-4 levels and tended to directly proportionate IFN-gamma levels in the supernatants recovered on days 2 and 4. Thereafter, we examined the effects of rIFN-gamma, rIL-4, and rIL-10 on mast cell induction. IFN-gamma and IL-10 dose-dependently induced mast cells. Time course study showed an importance of adding rIFN-gamma into the cultures at the early phase (on days 0 and 2 of a 12-day culture). When endogenous IFN-gamma at the early phase was neutralized by anti-IFN-gamma Ab, all stimulants, including rIFN-gamma, rIL-10, and PGE1, failed to induce mast cells. On the contrary, rIL-4 dose-dependently suppressed the mast cell induction by rIFN-gamma, rIL-10, LPS, PGE, and dibutyryl cAMP. The inhibitory effect of IL-4 was observed when IL-4 was added into the cultures at the early phase, but not after day 4. The suppressive action of IL-4 was diminished completely by the addition of neutralizing anti-IL-4 Ab. IL-12, a key regulator of IFN-gamma and IL-4 production, also induced mast cells. These results revealed, for the first time, that IFN-gamma is crucial for the survival and/or differentiation of splenic mast cell precursors and that IL-4 is a key inhibitor for the precursors, although IFN-gamma is not a mast cell growth factor and IL-4 is a growth factor for immature and mature mast cells.

Animals↗

PubMed1996

Preliminary application of Gamma Knife in the treatment of nasopharyngeal carcinoma.

Nasopharyngeal carcinoma is a malignant tumor which occurs frequently in China. Currently, radiotherapy using 60Co is the main method of treatment. However, the 5-year survival rate is only 49.5%. There is no effective method today for treating residual or recurrent tumor following radiotherapy. In principle, the Leksell Gamma Knife could contribute to better results. Since December 1993, we have treated 36 patients suffering from nasopharyngeal carcinoma with the Gamma Knife: 32 were relapses after radiotherapy and 4 were primary cases. Treatment was very effective for a short period. The rate of improvement of such symptoms as headache, facial paralysis, reduced vision, nasal obstruction and nasal bleeding was 70-100%. After treatment, tumors became smaller or even disappeared. A new nasopharyngeal biopsy was performed in 12 patients and demonstrated that the pathological tissue had returned to normal. The short duration of the survey precludes conclusions about the long-term effects of the treatment.

Adult↗

PubMed1995

An essential role of prostaglandin E on mouse mast cell induction.

We previously established a system for induction of mucosal-type mast cells from mouse spleen cells by long term culture without exogenous IL-3. FCS was important and was able to be divided into mast cell-inducible and non-mast cell-inducible sera. LPS contaminated in FCS was responsible for the mast cell induction. However, we unexpectedly found that both supernatants recovered from the cultures with mast cell-inducible and non-mast cell-inducible sera contained endogenous IL-3. Furthermore, addition of rIL-3 to the cultures with non-mast cell-inducible sera had no effect or induced only a small number of mast cells. This indicates that IL-3 alone is not enough for mast cell induction and that some inflammatory factor(s) induced by LPS is also essential. Prostaglandin E1 (PGE1) and PGE2 induced mast cells in a dose-dependent manner when added into the cultures. The activity of LPS for mast cell induction was inhibited by indomethacin. However, indomethacin failed to inhibit the mast cell induction by exogenous PGE. Exogenous PGE antagonized the indomethacin-induced inhibition of mast cell induction by LPS. Cholera toxin and dibutyryl cyclic AMP (cAMP) also induced mast cells. The A and B subunits of cholera toxin, PGF2 alpha, PGD2, and dibutyryl cGMP failed to induce mast cells. Furthermore, mast cell induction by PGE was dose-dependently suppressed by inhibitors for cAMP-dependent A kinase. The above results show that for mast cell induction, IL-3 needs the cooperation of PGE or other stimulants that can elevate the production of the second messenger cAMP in mast cell precursors.

Animals↗

PubMed1994

Effect of lipopolysaccharide on mouse mast cell induction by a splenic cell culture system.

We have previously reported a method of mast cell induction by long-term culture of mouse spleen cells without using exogenous mast cell growth factor (Z.-Q. Hu, T. Yoshida, and T. Shimamura, J. Immunol. Methods 149:173, 1992). Supernatants recovered from the long-term cultures contain endogenous interleukin 3 and soluble stem cell factor. These were assessed by the capacity of the recovered supernatants to foster the growth of a mast cell growth factor-dependent cell line and by neutralizing antibodies. Besides the soluble factors, cell-to-cell contacts mediated by membrane stem cell factor on splenic stromal cells and c-Kit receptors on mast cells also affect mast cell induction. Different lots of fetal calf serum (FCS) were examined to determine a possible trigger for cytokine production. FCS can be divided into mast cell-inducible and noninducible sera by this process. However, not all FCS lots contain mast cell growth factor. The mast cell-inducible lots contain lipopolysaccharide (LPS) confirmed by a Limulus assay. Polymyxin B can neutralize the mast cell induction activity. Non-mast cell-inducible FCS can be converted to inducible FCS by adding exogenous LPS. The results indicate that LPS as a trigger of cytokine production is responsible for mast cell induction.

Animals↗

PubMed1994

Biotin uptake by basolateral membrane vesicles of human placenta: normal characteristics and role of ethanol.

This study assessed the mechanism of uptake of biotin by the fetal-facing (basolateral) membrane of the term human placenta. Using membrane vesicles, we showed that most of the uptake was attributable to transfer of the vitamin into the vesicle and that the uptake was saturable, Na-dependent, carrier-mediated, and electroneutral. The rate of uptake was less than for biotin uptake by the maternal-facing (apical) membrane of the human placenta. Because ethanol inhibits biotin uptake by the apical membrane, the effect of ethanol on uptake by basolateral vesicles was investigated. With 10-hr exposure at a concentration of 2 and 3 mg/ml, but not 1 mg/ml, ethanol modestly inhibited biotin uptake. The mechanism of inhibition by alcohol is not known.

Biotin↗