Biomedical subjects

P Fu

Publications and source records attributed to P Fu.

At least 19 recordsLinked to original sources

PubMed2006

Superior ex vivo cord blood expansion following co-culture with bone marrow-derived mesenchymal stem cells.

One factor limiting the therapeutic efficacy of cord blood (CB) hematopoietic progenitor cell (HPC) transplantation is the low cell dose of the graft. This is associated with an increased incidence of delayed or failed engraftment. Cell dose can be increased and the efficacy of CB transplantation potentially improved, by ex vivo CB expansion before transplantation. Two ex vivo CB expansion techniques were compared: (1) CD133+ selection followed by ex vivo liquid culture and (2) co-culture of unmanipulated CB with bone-marrow-derived mesenchymal stem cells (MSCs). Ex vivo culture was performed in medium supplemented with granulocyte colony-stimulating factor, stem cell factor and either thrombopoietin or megakaryocyte growth and differentiation factor. Expansion was followed by measuring total nucleated cell (TNC), CD133+ and CD34+ cell, colony-forming unit and cobblestone area-forming cell output. When compared to liquid culture, CB-MSC co-culture (i) required less cell manipulation resulting in less initial HPC loss and (ii) markedly improved TNC and HPC output. CB-MSC co-culture therefore holds promise for improving engraftment kinetics in CB transplant recipients.

AC133 Antigen↗

PubMed2006

Pre-mobilization therapy blood CD34+ cell count predicts the likelihood of successful hematopoietic stem cell mobilization.

We examined pre-mobilization blood CD34+ cell count to predict ability to mobilize adequate peripheral blood progenitor cells (PBPC) in 106 cancer patients and 36 allogeneic donors. Mean pre-mobilization therapy blood CD34+ cell count was 3.1 cells x 10(6)/l (s.d. = 3.9, r = 0.3-37) and mean CD34+ cells collected were 5.3 x 10(6) cells/kg/leukapheresis procedure (s.d. = 7.0, r = 0.03-53). Yields correlated with pre-mobilization CD34+ cells x 10(6)/l (r = 0.37, P-value < 0.0001); correlation was stronger in allogeneic donors (r = 0.56, P-value = 0.0004) and males (r = 0.46, P-value < 0.0001). Based on classification and regression tree multivariate analysis, the predictive value of pre-mobilization blood CD34+ cell count was confounded by other variables, including age, gender, mobilization regimen and malignancy type. We generated an algorithm to predict a minimum PBPC yield of 1 x 10(6) CD34+ cells/kg/leukapheresis procedure after mobilization. A threshold pre-mobilization blood CD34+ cell count of 2.65 cells x 10(6)/l was the most important decision point in predicting successful mobilization. Only 2% of subjects with pre-mobilization blood CD34+ cell counts > 2.65 cells x 10(6)/l did not achieve the minimum per apheresis, whereas 24% with pre-mobilization values below threshold had inadequate mobilization. Prospectively identifying individuals at risk for mobilization failure would allow for improved treatment planning, resource utilization and time saving.

Adolescent↗

PubMed2006

Two new xanthones from Hypericum japonicum.

Two new xanthones, 1,6-dihydroxyisojacereubin-5-O-beta-D-glucoside (1) and 3,6,7-tri-hydroxy-1-methoxy-xanthone (2), were isolated from Hypericum japonicum. The structural elucidation of the isolated compounds were primarily based on HREIMS, EIMS, UV, IR, 1D-, and 2D-NMR analyses, including COSY, HMQC, HMBC, and NOESY correlations.

China↗

PubMed2006

Leucine-rich repeat-containing G-protein-coupled receptor 8 in mature glomeruli of developing and adult rat kidney and inhibition by insulin-like peptide-3 of glomerular cell proliferation.

Leucine-rich repeat-containing G-protein-coupled receptor 8 (LGR8, or RXFP2) is a member of the type C leucine-rich repeat-containing G protein-coupled receptor family, and its endogenous ligand is insulin-like peptide-3 (INSL3). Although LGR8 expression has been demonstrated in various human tissues, including testis, ovary, brain and kidney, the precise roles of this receptor in many of these tissues are unknown. In an effort to better understand INSL3-LGR8 systems in the rat, we cloned the full-length Lgr8 cDNA and investigated the presence and cellular localization of Lgr8 mRNA expression in adult and developing rat kidney. On the basis of these findings, we investigated the presence and distribution of renal 125I-labelled human INSL3-binding sites and the nature of INSL3-LGR8 signalling in cultured renal cells. Thus, using in situ hybridization histochemistry, cells expressing Lgr8 mRNA were observed in glomeruli of renal cortex from adult rats and were tentatively identified as mesangial cells. Quantitative, real-time PCR analysis of the developmental profile of Lgr8 mRNA expression in kidney revealed highest relative levels at late stage gestation (embryonic day 18), with a sharp decrease after birth and lowest levels in the adult. During development, silver grains associated with Lgr8 mRNA hybridization were observed overlying putative mesangial cells in mature glomeruli, with little or no signal associated with less-mature glomeruli. In adult and developing kidney, specific 125I-INSL3-binding sites were associated with glomeruli throughout the renal cortex. In primary cultures of glomerular cells, synthetic human INSL3 specifically and dose-dependently inhibited cell proliferation over a 48 h period, further suggesting the presence of functional LGR8 (receptors) on these cells (mesangial and others). These findings suggest INSL3-LGR8 signalling may be involved in the genesis and/or developmental maturation of renal glomeruli and possibly in regulating mesangial cell density in adult rat kidney.

Animals↗

PubMed2005

Uncoupling of oxidative phosphorylation prevents the urinary alcohol level cycling caused by feeding ethanol continuously at a constant rate.

The mechanism of the UAL cycle in the intragastric feeding model of alcoholic liver disease in the rat was investigated by administering dinitrophenol (DNP) with ethanol in the diet. The question was: is the rate of oxidative phosphorylation fluxuation essential for the cycle to occur? The question has been partially answered by showing that rotenone, which inhibits complex I, blocks the cycle by preventing the generation of NAD from NADH. This would inhibit ATP generation from complex I but would not affect oxidative phosphorylation by complex 2 and 3. Since the rate of O2 consumption is normal at the troughs of the cycle and decreases at the peaks of the cycle and the levels of ATP are reduced at the peaks of the cycle, it is likely that the rate of oxidative phosphorylation also cycles. Since 2-4 dinitrophenol (DNP) uncouples oxidative phosphorylation, it was anticipated that feeding it with ethanol would prevent the cycle from occurring. This proved to be the case. In addition, DNP caused energy wasting and prevented the increase in serum alanine aminotranspeptidase caused by ethanol feeding, probably by preventing the hypoxia which occurs at the peaks of the cycle.

2,4-Dinitrophenol↗

PubMed2005

Tissue engineering of vascular conduits: fabrication of custom-made scaffolds using rapid prototyping techniques.

BACKGROUND: The technique of stereolithography, which automatically fabricates models from X-ray computed tomography or magnetic resonance imaging (MRI) data linked to computer-aided design programs, has been applied to the fabrication of scaffolds for tissue engineering. We previously reported on the application of stereolithography in scaffold fabrication of a trileaflet heart valve. In our current experiment we demonstrate a new technique for the fabrication of custom-made conduits for the potential replacement of a coarcted aortic segment. METHODS AND RESULTS: In this experiment the image data derived from a 12-year-old male patient with aortic coarctation scanned by MRI were processed by a computer-aided design program to reconstruct the aortic arch with isthmus stenosis three dimensionally. By defining the stenotic section and the adjacent normal vessel a custom-made nonstenotic descending aorta was reconstructed to replace the stenosed part. The rapid prototyping technique was used to establish stereolithographic models for fabricating biocompatible and biodegradable vascular scaffolds with the anatomic structure of the recalculated human descending aorta through a thermal processing technique. CONCLUSION: Our results suggest that the re-creation and reproduction of complex vascular structures by computer-aided design techniques may be useful to fabricate custom-made polymeric scaffolds for the tissue engineering of living vascular prostheses.

Aortic Coarctation↗

PubMed2005

Ex vivo expansion of umbilical cord blood.

The efficacy of cord blood (CB) transplantation is limited by the low cell dose available. Low cell doses at transplant are correlated with delayed engraftment, prolonged neutropenia and thrombocytopenia and elevated risk of graft failure. To potentially improve the efficacy of CB transplantation, approaches have been taken to increase the cell dose available. One approach is the transplantation of multiple cord units, another the use of ex vivo expansion. Evidence for a functional and phenotypic heterogeneity exists within the HSC population and one concern associated with ex vivo expansion is that the expansion of lower 'quality' hematopoietic progenitor cells (HPC) occurs at the expense of higher 'quality' HPC, thereby impacting the reserve of the graft. There is evidence that this is a valid concern while other evidence suggests that higher quality HPC are preserved and not exhausted. Currently, ex vivo expansion processes include: (1) liquid expansion: CD34+ or CD133+ cells are selected and cultured in medium containing factors targeting the proliferation and self-renewal of primitive hematopoietic progenitors; (2) co-culture expansion: unmanipulated CB cells are cultured with stromal components of the hematopoietic microenvironment, specifically mesenchymal stem cells (MSC), in medium containing growth factors; and (3) continuous perfusion: CB HPC are cultured with growth factors in 'bioreactors' rather than in static cultures. These approaches are discussed. Ultimately, the goal of ex vivo expansion is to increase the available dose of the CB cells responsible for successful engraftment, thereby reducing the time to engraftment and reducing the risk of graft failure.

Cell Culture Techniques↗

PubMed2005

Kaposi's sarcoma in patients with and without human immunodeficiency virus infection, in a tertiary referral centre in Kenya.

The clinical features of Kaposi's sarcoma (KS), in patients with and without HIV infection, were investigated in a tertiary referral centre in Kenya between 1997 and 1999. Although 186 cases were identified prospectively, the data analysis was restricted to the 91 (49%) cases who had pathological confirmation of Kaposi's sarcoma and documented HIV serostatus. Among these 91 subjects (58% of whom were male), the age-group holding the largest number of KS cases was that of individuals aged 31-40 years; most of the paediatric cases were aged 6-10 years. The ratio of HIV-seropositives to HIV-seronegatives was 8.5:1 for the adult cases and 0.9:1 for the paediatric. Of the signs and symptoms of Kaposi's sarcoma seen at presentation, only peripheral lympadenopathy was found to be significantly associated with underlying HIV infection (P = 0.05). The median survival was 104 days. It is apparent that, as the HIV epidemic advances in regions of the world with endemic KS, the clinical presentation and natural history of the endemic KS are blending with those of the epidemic or AIDS-associated disease, leading to a reduction in the mean age of the cases and a nearly identical incidence in men and women. In regions of the world where patients have ready access to such chemotherapy, the impact of treatment with highly active antiretroviral drugs on the incidence and natural history of KS has been dramatic. It will be important to monitor the clinico-pathological features of KS in the developing world, as more active antiretroviral regimens become available in clinical practice there.

Adult↗

PubMed2005

Characterization of the rat INSL3 receptor.

Human LGR8, initially discovered as a low-affinity relaxin receptor, has now been characterized as the INSL3 receptor. To investigate LGR8 function in the rat, an LGR8 ortholog was identified in the rat genome, and the full-length sequence was cloned and expressed. Rat LGR8 bound INSL3 with high affinity, clearly demonstrating that it is the rat INSL3 receptor. Interestingly, native rat relaxin did not activate rat LGR8, indicating that relaxin is not an endogenous ligand for rat LGR8. LGR8 mRNA expression was demonstrated in the gubernaculum at the time of testis descent and in the testis associated with germ cells.

Animals↗

PubMed2005

Oral combination chemotherapy in the treatment of AIDS-associated Hodgkin's disease.

OBJECTIVES: To determine the effectiveness of an oral combination chemotherapy regimen administered to patients with AIDS-associated Hodgkin's disease. DESIGN: Prospective, pilot phase II clinical trial. SETTING: Consecutive patient recruitment occurred at two medical centers in the United States: Albany Medical Center, Albany, New York, where patients were recruited prior to December 31, 1996 (pre-HAART era); and University Hospitals of Cleveland, Cleveland, Ohio, where patients were recruited after January 1, 1997 (HAART era). INTERVENTION: Oral chemotherapy consisted of lomustine (100 mg/m2 day I for cycle one and odd cycles thereafter); etoposide (200 mg/m2 days 1 through 3); and cyclophosphamide and procarbazine (each 100 mg/m2 days 22 through 31). Cycles were repeated every six weeks. Colony-stimulating factor support (G-CSF in all instances) was allowed. MAIN OUTCOME MEASURES: Clinical demographic variables, peripheral blood counts, serum chemistries, CD4 lymphocyte count, histopathological subtype of Hodgkin's disease were identified for all patients, who were staged according to Ann Arbor criteria. DATA ANALYSIS: Common Toxicity Criteria were utilized to assess safety; response was assessed using ECOG criteria; and survival was analyzed by Kaplan-Meier methods and difference of survival between pre-HAART and HARART era was compared using log-rank test. RESULTS: Eleven patients (six in pre-HAART era), all but one male, with a median age of 36 years, excellent performance status and advanced International Prognostic Score were treated. Myelosuppression was the major side effect and there were minimal other grade 3 or greater toxicity all of which were promptly reversible. An overall objective response rate of 82% (with 18% complete responses) and median survival duration of 24 months (range 2.5 +/- 68) were observed. Survival was markedly improved in patients treated in the HAART era (median not reached versus 7.25 months, p = 0.034). CONCLUSIONS: This feasibility study demonstrates acceptable tolerance and excellent clinical activity of oral combination chemotherapy in patients with AIDS-associated Hodgkin's disease. Improved survival is observed in combination with HAART therapy. Dose-modification of this regimen would be suitable to evaluate in the resource constrained setting and larger confirmatory studies are encouraged.

Adult↗

PubMed2004

The effect of Viagra (sildenafil citrate) on liver injury caused by chronic ethanol intragastric feeding in rats.

Rats fed with ethanol and a nutritious diet intragastrically develop liver pathologic changes associated with cyclic elevation of blood and urinary ethanol levels (BAL and UAL cycle). At the peaks of the UAL cycle, the livers are hypoxic. When the liver portal hepatic blood flow is temporarily clamped for 2 min and then released, the livers at the peak UAL fail to recover completely compared to the control livers and the livers at the UAL cycle troughs. Viagra was fed to the ethanol-fed rats to enhance the effects of nitric oxide. Since nitric oxide is known to increase hepatic blood flow, it was anticipated that Viagra would prevent the liver hypoxia at the UAL cycle peaks and also improve the post-clamp recovery from the post-clamp ischemia challenge. Viagra tended to improve the post-clamp recovery of the liver surface pO2 levels of the ethanol-fed rats probably by slowing O2 consumption as result of NO inhibition of mitochondrial cytochrome c oxidase activity. However, Viagra increased the pathology score when fed with ethanol. For this reason, Viagra is a two-edged sword. On the one hand, it tended to be protective in the post-ischemic injury in the ethanol-fed rats and on the other hand, it enhanced the liver injury caused by ethanol. Viagra did not affect the UAL cycle.

Animals↗

PubMed2004

The effect of rotenone on the urinary ethanol cycle in rats fed ethanol intragastrically.

Chronic ethanol ingestion alters mitochondrial function in the liver including inhibition of complex I of the electron transport chain. This leads to a shift in the NAD/NADH ratio to the reduced state when blood ethanol levels are high. Rotenone also inhibits complex I and induces a reduced state. The combination of ethanol feeding and rotenone toxicity should amplify the reduced state and block the cyclic increase and decrease in the rate of metabolism in the liver. The change in the redox state occurs during the urinary ethanol cycle in the intragastric tube feeding rat model of alcoholic liver disease. To test this hypothesis, rats were fed ethanol with rotenone and the 24-h urinary ethanol levels were measured daily. When ethanol was fed alone, the urinary ethanol cycle occurred. However, when ethanol was fed with rotenone the cycle was prevented and the urinary ethanol levels remained at the 200-mg% range. The rats fed ethanol or fed ethanol plus rotenone had the same increase in the pathology score and ALT elevations in the blood. Rotenone fed alone had the same normal values as the dextrose pair fed control rats. The results indicate that the UAL cycle is driven by fluctuation in the NAD/NADH ratio. When this fluctuation is blocked by rotenone, the cycle does not occur. It is concluded that the urinary ethanol cycle is dependent on cyclic fluctuation of the NAD/NADH ratio, which regulates the rate of ethanol elimination.

Administration, Oral↗

PubMed2004

Synthesis, conformation, receptor binding and biological activities of monobiotinylated human insulin-like peptide 3.

Biotin-avidin immobilization has been routinely used as a tool to study peptide-receptor and peptide-antibody interactions. Biotinylated peptides can also be employed to localize cells that express the peptides' receptor, and to analyse ligand-receptor binding. Insulin-like peptide 3 (INSL3) is a peptide hormone which contains A- and B-chains connected by two disulphide bonds and plays a role in testicular descent during sexual development. In order to study the interaction of INSL3 with its receptor LGR8, a G protein-coupled receptor, we chemically synthesized Nalpha-mono-biotinylated human INSL3 (B-hINSL3) and compared it structurally and biologically with hINSL3. Both peptides exhibited similar, but high, receptor binding affinities on human foetal kidney fibroblast 293T cells transfected human LGR8 based on a competition radioreceptor assay with 33P-labelled relaxin H2 (B33). The modified B-hINSL3 showed full biological activity as determined by the stimulation of gubernacular cell proliferation. The labelled B-hINSL3 contains a higher alpha-helix content, and this increased helical structure is accompanied by an increase in ability to stimulate cAMP accumulation in 293T cells expressing LGR8. Our results suggest that the N-terminal region of the A-chain is not involved in the interaction of INSL3 with its receptor. However, the introduction of biotin onto the N-terminus of the A-chain promoted conformational stability which, in turn, permitted better receptor activation.

Amino Acid Sequence↗

PubMed2003

Quantitative analysis of Escherichia coli metabolic phenotypes within the context of phenotypic phase planes.

In silico models of Escherichia coli metabolism have been developed to predict metabolic behavior and propose experimentally testable hypotheses. However, a thorough assessment of the metabolic phenotype requires well-designed experimentation and reproducible experimental techniques. A method for the quantitative analysis of E. coli metabolism in vivo within the framework of in silico phenotypic phase plane analysis is presented. Using this approach, we have quantitatively studied E. coli metabolism in various environmental conditions and nutritional media. Our experimental methodology, in combination with steady-state metabolic models, can be used to study biological properties and evaluate the metabolic capabilities of microbes.

Aerobiosis↗

PubMed2001

Tactic-specific success in sperm competition.

Sperm competition is a major force in sexual selection, but its implications for mating-system and life-history evolution are only beginning to be understood. The well-known sneak-guard model predicts that sneaks will win in sperm competition. We now provide empirical confirmation of this prediction. Bluegill sunfish (Lepomis macrochirus) have both sneak (cuckolder) and guard (parental) males. Guards make nests, court females and provide solitary parental care for the embryos. Sneaks include small cuckolders, which are termed 'sneakers', that dart in and out of nests in order to ejaculate between the spawning pair and larger cuckolders, which are termed 'satellites', that mimic females in order to ejaculate between the spawning pair. Using field behavioural data, genetic data and new mathematical models for paternity analyses, we show, for the first time to the authors' knowledge, that sneaks fertilize more eggs than guards during sperm competition. In addition, we show that sneakers are superior to satellites in sperm competition and, thus, that even among sneaks there are tactic-specific differences in competitive success.

Animals↗

PubMed2001

Liver necrosis induced by thyroid hormone administration in rats fed ethanol.

Recently it was observed that the hypothyroid state induced by propylthiouracil treatment reduced the elimination rate of ethanol. This was based on the fact that hypothyroid rats could only tolerate 10 g/kg/day of ethanol infusion over 24 h. Euthyroid rats tolerate 13 to 14 g/kg/day of ethanol infusion. In the present report it was postulated that thyroid supplements would increase the daily dose of ethanol that the treated rats could tolerate. Daily thyroid supplements, given intraperitoneally or orally, did, in fact, result in an increase in the elimination rate of ethanol. Death from ethanol overdose did not occur until the amount of ethanol given reached 16 to 19 g/kg/day. In addition, thyroxine supplements blunted or completely inhibited the urinary ethanol cycle. Submassive centrilobular liver necrosis was present in 9 of 10 rats given thyroid hormone and fed ethanol. Periportal duct metaplasia and fibrosis were also observed. Thus, thyroid supplements probably enhanced central hypoxia caused by ethanol to the point where ischemic necrosis developed. The latter healed by scar formation. Thyroid treatment completely prevented ethanol-induced steatohepatitis, indicating that the fatty change is responsive to the metabolic rate.

Administration, Oral↗

PubMed2001

Oral low-carbohydrate alcohol liquid diet induces experimental steatohepatitis in the rat.

The intragastric tube feeding model of alcoholic liver disease in the rat induces significant liver histopathology, including steatohepatitis and fibrosis. The question is, if the same low-carbohydrate diet is fed ad lib, will the same pathology develop? Rats were fed a liquid diet with ethanol ad lib that was low in calories derived from carbohydrates for 2 months. The urinary ethanol levels (UALs) were monitored at hourly, daily, and weekly intervals, and the growth of the rats was charted. The liver histopathology and blood transaminase levels were determined. Rats fed ethanol grew 1 g/day, which was 2 g/day less than when they were fed the same diet intragastrically. UALs varied hourly between 150 and 500 mg%, daily between 120 and 360 mg%, and weekly between 0 and 500 mg%. Individual rat UALs showed no predictable pattern. The pair-fed controls ate all of their daily ration within 12 h, then fasted until the next day. The histopathology and blood alanine aminotransferase were similar to those seen with the intragastric tube feeding of the same diet, except that necrosis, inflammation, and fibrosis did not develop. The conclusion was that the oral feeding of a low-carbohydrate diet produces less liver injury than that produced by the same diet fed intragastrically. The UALs varied hourly, daily, and weekly in individual rats, making it difficult to synchronize UALs at the time of sacrifice.

Administration, Oral↗

PubMed2001

Total cavopulmonary connection for complex cardiac anomalies with the functional single ventricle.

From Aug. 1999 to Feb. 2001, 8 patients with complex congenital heart diseases, including 5 cases accompanied by hypoplastic left ventricle and 3 by hypoplastic right ventricle, were subjected to total cavopulmonary connection (TCPC). Eight cases underwent the operation under cardiopulmonary bypass and 7 of whom under no cardiac clamp. Seven cases received cavopulmonary anastomosis by flaring method and one case by end-side anastomosis. All the patients underwent the intracardiac tunnels to drain inferior vena cava and plus 4 mm fenestration except one. The results showed that 6 patients had postoperative oxygen saturation more than 90%, sinus rhythm, no anastomostic stoma obstruction, no flow regurgitation and CVP < 16 cmH2O. Two (25%) patients died postoperatively from high venous pressure of 18-20 cmH2O, finally from cardiac failure and anoxima. It was concluded that TCPC was an effective treatment for complex congenital cardiac diseases, especially with ventricular maldevelopment. Intracardiac tunnel plus 4 mm fenestration and flaring cavopulmonary anastomosis could prevent the postoperative complications. Larger anastomotic stoma, venous pressure less than 16 cmH2O and artery saturation more than 90% might indicate excellent TCPC procedures in our experience.

Child↗