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Biomedical subjects

N Uchida

Publications and source records attributed to N Uchida.

At least 73 records · Page 4Linked to original sources

Synchronized oscillatory discharges of mitral/tufted cells with different molecular receptive ranges in the rabbit olfactory bulb.

Individual glomeruli in the mammalian olfactory bulb represent a single or a few type(s) of odorant receptors. Signals from different types of receptors are thus sorted out into different glomeruli. How does the neuronal circuit in the olfactory bulb contribute to the combination and integration of signals received by different glomeruli? Here we examined electrophysiologically whether there were functional interactions between mitral/tufted cells associated with different glomeruli in the rabbit olfactory bulb. First, we made simultaneous recordings of extracellular single-unit spike responses of mitral/tufted cells and oscillatory local field potentials in the dorsomedial fatty acid-responsive region of the olfactory bulb in urethan-anesthetized rabbits. Using periodic artificial inhalation, the olfactory epithelium was stimulated with a homologous series of n-fatty acids or n-aliphatic aldehydes. The odor-evoked spike discharges of mitral/tufted cells tended to phase-lock to the oscillatory local field potential, suggesting that spike discharges of many cells occur synchronously during odor stimulation. We then made simultaneous recordings of spike discharges from pairs of mitral/tufted cells located 300-500 microm apart and performed a cross-correlation analysis of their spike responses to odor stimulation. In approximately 27% of cell pairs examined, two cells with distinct molecular receptive ranges showed synchronized oscillatory discharges when olfactory epithelium was stimulated with one or a mixture of odorant(s) effective in activating both. The results suggest that the neuronal circuit in the olfactory bulb causes synchronized spike discharges of specific pairs of mitral/tufted cells associated with different glomeruli and the synchronization of odor-evoked spike discharges may contribute to the temporal binding of signals derived from different types of odorant receptor.

Aldehydes↗

Changes in serum leptin concentration during behavioral therapy in obese children.

To determine the pathophysiological implications of serum leptin level in obesity, we monitored the changes in serum leptin level during outpatient treatment with life style modification in children. Fifty-five obese Japanese children (34 boys and 21 girls; mean age, 9.64 years) were studied. The control children consisted of 42 nonobese subjects (27 boys and 15 girls). The serum leptin concentration was 4.35 +/- 0.46 ng/ml (mean +/- SEM) in the control girls and 2.93 +/- 0.21 ng/ml in the control boys. The serum leptin concentrations in the obese boys and girls were higher than those in their lean counterparts. The concentration in the obese boys (16.28 +/- 1.41 ng/ml) was similar to that in the obese girls (20.33 +/- 2.0 ng/ml). The logarithmic value of serum leptin concentration at the first blood sampling in obese children was correlated with percent overweight and percent body fat. In 36 obese children (24 boys and 12 girls) whose serum leptin concentrations were monitored serially during treatment of obesity, the percent overweight was significantly decreased after the initial sampling. In each individual, the changes in leptin concentration were roughly parallel to those in percent overweight. The ratio of the leptin concentration at the second blood sampling divided by the one at the first sampling in each individual was closely correlated with the respective delta percent overweight. These results suggest that the preceding course of obesity determines the serum leptin level of obese children on longitudinal basis, and that the leptin level reflects the degree of obesity on cross-sectional basis.

Behavior Therapy↗

[Myelodysplastic syndrome after autologous peripheral blood stem cell transplantation for adult acute myelogenous leukemia].

A 65-year-old woman was admitted to our hospital with arthritis and agranulocytosis. She had given a diagnosis of acute myelogenous leukemia (FAB classification M1) a year ago and treated with 3 cycles of cytarabine and anthracycline or etoposide for 4 months, achieving complete remission state. Her bone marrow aspirate revealed normocellularity with normal karyotype (46, XX [20]) without apparent dysplastic feature at this time. She received autologous peripheral blood stem cell transplantation subsequently after conditioning regimen consisted of granulocyte colony-stimulating factor, busulfan, Ara-C and etoposide. Three months later, she started to manifest low grade fever, polyarthralgia and agranulocytosis and she admitted to our hospital after nine months. Bone marrow aspirate revealed marked hypocellularity with dysplastic features in three series of hematopoietic cells. Arthritis was dramatically improved after administration of prednisolone, but low granulocyte count continued. Bone marrow aspirate revealed karyotypic abnormality with monosomy 7 and we diagnosed her as myelodysplastic syndrome. Chemotherapy-induced myelodysplasia has been reported so far. This case would represent secondary myelodysplastic syndrome after chemotherapy. We could not clarify the etiology for polyarthritis but could be one of the paraneoplastic syndrome. We should note subsequent occurrence of myelodysplasia when planning treatment schedule.

Aged↗

[Antiangiogenic and antitumor effect of BPHA, an orally-active matrix metalloproteinase inhibitor, in in vivo murine and human tumor model].

We examined the antiangiogenic and antitumor efficacy of a newly-developed matrix metalloproteinase (MMP) inhibitor, BPHA (N-biphenyl sulfonyl-phenylalanine hydroxiamic acid). BPHA potently inhibits MMP-2, 9 and 14 but not MMP-1, 3 or 7. In contrast, (-)BPHA, an enantiomer of BPHA, was inactive against all MMP tested. Daily oral administration of BPHA in mice resulted in potent inhibition of tumor-induced angiogenesis, primary tumor growth and liver metastasis, whereas (-)BPHA did not. These results demonstrate that selective MMP inhibition is correlated with antiangiogenic and antitumor efficacy and that the selective MMP inhibitor BPHA has therapeutic potential without hematotoxic effect or loss of body weight.

Animals↗

Novel function of the eukaryotic polypeptide-chain releasing factor 3 (eRF3/GSPT) in the mRNA degradation pathway.

The mammalian GTP-binding protein GSPT, whose carboxy-terminal sequence is homologous to the eukaryotic elongation factor EF1alpha, binds to the polypeptide chain releasing factor eRF1 to function as eRF3 in translation termination. However, the amino-terminal domain of GSPT, which contains a prion-like sequence, is not required for the binding. Instead, the amino-terminal domain is capable of binding to the carboxy-terminal domain of polyadenylate-binding protein (PABP), whose amino terminus is associating with the poly(A) tail of mRNAs, presumably for their stabilization. Interestingly, multimerization of PABP with poly(A), which is ascribed to the action of its carboxy-terminal domain, was completely inhibited by the interaction with the amino-terminal domain of GSPT. This may facilitate shortening of the poly(A) tail of mRNAs by an RNase. Thus, GSPT/eRF3 appears to function not only as a stimulator of eRF1 in the translation termination but also as an initiator of the mRNA degradation machinery. Further physiological and cell biological approaches will be necessary to show whether our current in vitro findings on GSPT/eRF3 indeed reflect its bifunctional properties in living cells.

Animals↗

HIV, but not murine leukemia virus, vectors mediate high efficiency gene transfer into freshly isolated G0/G1 human hematopoietic stem cells.

Recent studies have opened the possibility that quiescent, G0/G1 hematopoietic stem cells (HSC) can be gene transduced; lentiviruses (such as HIV type 1, HIV) encode proteins that permit transport of the viral genome into the nucleus of nondividing cells. We and others have recently demonstrated efficient transduction by using an HIV-1-based vector gene delivery system into various human cell types including human CD34(+) cells or terminally differentiated neurons. Here we compare the transduction efficiency of two vectors, HIV-based and murine leukemia virus (MuLV)-based vectors, on untreated and highly purified human HSC subsets that are virtually all in G0/G1. The HIV vector, but not MuLV vector supernatants, transduced freshly isolated G0/G1 HSC from mobilized peripheral blood. Single-step transduction using replication-defective HIV resulted in HSC that expressed the green fluorescent protein (GFP) transgene while retaining their stem cell phenotype; clonal outgrowths of these GFP+ HSC on bone marrow stromal cells fully retained GFP expression for at least 5 weeks. MuLV-based vectors did not transduce resting HSC, as measured by transgene expression, but did so readily when the HSC were actively cycling after culture in vitro for 3 days in a cytokine cocktail. These results suggest that resting HSC may be transduced by lentiviral-based, but not MuLV, vectors and maintain their primitive phenotype, pluripotentiality, and at least in vitro, transgene expression.

Antigens, CD34↗

alpha-Catenin-vinculin interaction functions to organize the apical junctional complex in epithelial cells.

alphaE-catenin, a cadherin-associated protein, is required for tight junction (TJ) organization, but its role is poorly understood. We transfected an alphaE-catenin-deficient colon carcinoma line with a series of alphaE-catenin mutant constructs. The results showed that the amino acid 326-509 domain of this catenin was required to organize TJs, and its COOH-terminal domain was not essential for this process. The 326-509 internal domain was found to bind vinculin. When an NH2-terminal alphaE-catenin fragment, which is by itself unable to organize the TJ, was fused with the vinculin tail, this chimeric molecule could induce TJ assembly in the alphaE-catenin-deficient cells. In vinculin-null F9 cells, their apical junctional organization was impaired, and this phenotype was rescued by reexpression of vinculin. These results indicate that the alphaE-catenin-vinculin interaction plays a role in the assembly of the apical junctional complex in epithelia.

Binding Sites↗

Anticancer efficacy in vivo and in vitro, synergy with 5-fluorouracil, and safety of recombinant methioninase.

The elevated exogenous-methionine dependency of tumors for growth has been observed in all major cancer cell types. We have previously cloned a methioninase (rMETase) from Pseudomonas putida to deplete methionine. Growth inhibition followed by apoptotic cell death was induced by treatment of tumor cells with rMETase in vitro. A single i.p. injection of 300 units of rMETase can lower the serum methionine level in the mice from 70 microM to less than 1 microM within 2 h and maintain this depleted level for 8 h. Repeated dosing of rMETase of tumor-bearing mice could be administered without acute immune-hypersensitivity. rMETase treatment demonstrated growth inhibitory activity against human tumors in nude mice, including those which were multiple drug-resistant. No body weight loss or hematotoxicity, except a slight anemia, was found throughout the therapy. The combined treatment of the Lewis lung carcinoma with a fixed rMETase dose and increasing doses of 5-fluorouracil (5-FU) resulted in a dose-dependent enhanced antitumor efficacy for survival as well as tumor growth inhibition. Thus, methionine depletion by rMETase potentiates the antitumor efficacy of 5-FU. The data presented in this report thus indicate that rMETase is active alone, is synergistic in combination with 5-FU, and has negligible toxicity suggesting a novel clinical approach for effective cancer therapy.

Animals↗

High doses of purified stem cells cause early hematopoietic recovery in syngeneic and allogeneic hosts.

In humans, autologous transplants derived from bone marrow (BM) usually engraft more slowly than transplants derived from mobilized peripheral blood. Allogeneic BM transplants show a further delay in engraftment and have an apparent requirement for donor T cells to facilitate engraftment. In mice, Thy-1.1(lo)Lin-/loSca-1+ hematopoietic stem cells (HSCs) are the principal population in BM which is responsible for engraftment in syngeneic hosts at radioprotective doses, and higher doses of HSCs can radioprotect an allogeneic host in the absence of donor T cells. Using the mouse as a preclinical model, we wished to test to what extent engraftment kinetics was a function of HSC content, and whether at high doses of c-Kit+Thy-1.1(lo)Lin-/loSca-1+ (KTLS) cells rapid allogeneic engraftment could also be achieved. Here we demonstrate that engraftment kinetics varied greatly over the range of KTLS doses tested (100-10,000 cells), with the most rapid engraftment being obtained with a dose of 5,000 or more syngeneic cells. Mobilized splenic KTLS cells and the rhodamine 123(lo) subset of KTLS cells were also able to engraft rapidly. Higher doses of allogeneic cells were needed to produce equivalent engraftment kinetics. This suggests that in mice even fully allogeneic barriers can be traversed with high doses of HSCs, and that in humans it may be possible to obtain rapid engraftment in an allogeneic context with clinically achievable doses of purified HSCs.

Animals↗

Glutamate-stimulated proliferation of rat retinal pigment epithelial cells.

We investigated the effects of glutamate on cell proliferation and the expression of basic fibroblast growth factor (bFGF) and its receptor (FGF-R1) mRNA in cultured rat retinal pigment epithelial (RPE) cells. The number of primary RPE cells was significantly higher after treatment with 0.2 to 1.0 mM glutamate (maximum at 1.0 mM) for 7 days than in controls. Glutamate-stimulated cell proliferation was abolished by (+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imine (MK-801), but not by 6,7-dinitroquinoxaline-2,3-dione or L(+)-2-amino-3-phosphonopropionic acid. Proliferation was increased to a similar extent by N-methyl-D-aspartate (NMDA), but not by kainate, alpha-amino-3-hydroxy-3-methyl-4-isoxazolepropionic acid or trans-(+/-)-1-amino-1,3-cyclopentanedicarboxylic acid. NMDA-receptor-like immunoreactivity was detected in most cells cultured. Treatment of cells with glutamate increased the level of bFGF mRNA and, to a lesser extent, that of FGF-R1 mRNA, which peaked 2 and 4 days, respectively, after glutamate was added. The increase in bFGF mRNA induced by glutamate was inhibited by MK-801. These findings suggest that glutamate might stimulate proliferation of RPE cells through activation of NMDA receptors and expression of bFGF and further suggest that glutamate may be involved in the proliferative changes of RPE cells in retinal wound healing.

Animals↗

Effect of selenium deficiency on cellular and extracellular glutathione peroxidases: immunochemical detection and mRNA analysis in rat kidney and serum.

To determine the effect of selenium (Se) deficiency on expression of glutathione peroxidase (GSH-Px) 1 and 2, we measured GSH-Px activity in rat serum, liver and kidneys, serum immunoreactive GSH-Px 2, and the mRNAs of kidney GSH-Px 1 and 2. We purified rat GSH-Px 2 and raised polyclonal antibodies. Immunoreactive GSH-Px 2 was measured by rocket immunoelectrophoresis. GSH-Px 2 was purified 1470-fold with a specific activity of 250 units/mg. Immunoblotting detected only GSH-Px 2 in rat serum, and much less GSH-Px 2 than GSH-Px 1 in kidney. Immunoblot signal of kidney GSH-Px 1 and 2 decreased progressively in Se deficient rats. Serum GSH-Px activity in Se deficient rats at 1, 2, 3, and 4 weeks declined to 33, 20, 10, and 9% of the control, while the serum level of immunoreactive GSH-Px 2 was 58, 24, 15, and 10% of the control, suggesting the presence of an inactive protein at week 1. GSH-Px activity declined to 4 and 11% of the control in the liver and kidney at 4 weeks. The mRNAs of kidney GSH-Px 1 and 2 showed similar decreases, and were 24 and 23% of the control at 4 weeks. GSH-Px mRNA levels were better preserved than GSH-Px activity, suggesting that GSH-Px expression was regulated at both pre-translational and translational levels.

Animals↗

Sequence-dependent antitumour efficacy of combination chemotherapy of nedaplatin, a novel platinum complex, with 5-fluorouracil in an in vivo murine tumour model.

The antitumour efficacy of a sequential combination of nedaplatin (NDP) and 5-fluorouracil (5-FU) was evaluated using Lewis lung carcinoma in vivo. NDP was developed as a second generation platinum complex. Because it has greater antitumour activity and lower nephrotoxicity than cisplatin (CDDP), we also compared the antitumour activity of NDP plus 5-FU with that of CDDP plus 5-FU. A fixed 5-FU dose was injected daily for 5 days and increasing doses of either NDP or CDDP were injected once via the tail vein into the Lewis lung carcinoma-implanted mice. The sequential administration of either NDP or CDDP prior to 5-FU (NF or CF therapy) resulted in severe body weight loss followed by the death of the tumour-bearing mice when the high-dose of NDP or CDDP was administered. In contrast, the sequential administration of 5-FU prior to NDP or CDDP (FN or FC therapy) resulted in synergistically enhanced inhibition of tumour growth and prolonged survival in comparison with NDP, CDDP or 5-FU monotherapy. At the high-dose of NDP in FN therapy, a reduction of tumour size and long-term tumour-free survival were frequently observed. The survival effect of the combinations of NDP with 5-FU was superior to those of the combination of CDDP with 5-FU. In conclusion, the sequence-dependent antitumour efficacy and toxicity of the combination of NDP or CDDP with 5-FU was demonstrated in this study, and FN therapy appeared to be the most efficient regimen as a clinical therapy.

Animals↗

Relationships between an index of body fat distribution (based on waist and hip circumferences) and stature, and biochemical complications in obese children.

OBJECTIVE: To determine the clinical utility of a new age-adjusted measure of body fat distribution (based on waist and hip circumferences) and stature, in relation to biochemical complications in obese children. DESIGN: Cross-sectional, clinical study. The formula to calculate the common standard deviation score (SDS) of waist-to-hip ratio/height (WHR/Ht) was obtained from the data of control children. The relationship between WHR/Ht SDS, as the age-adjusted measure, in obese children and their clinical laboratory data was evaluated. SUBJECTS: Outpatient obese Japanese children (102 boys and 75 girls) and control children (508 boys and 549 girls), ranging in age from 6-15 y. MEASUREMENTS: Height, body weight, waist girth, hip girth, triceps and subscapular skinfold thicknesses, as anthropometric measures. Percent overweight, percent body fat, waist girth, WHR and WHR/Ht SDS as criteria for obesity. Clinical laboratory analyses for fasting blood samples of obese children. RESULTS: The WHR/Ht SDS closely correlated with age in obese children, thus reflecting the progress of abdominal obesity during growth. The obese boys were more hyperlipidaemic than the girls were, although the percent overweight was similar in both genders. The percent overweight, percent body fat, waist girth and WHR/Ht SDS all correlated well with triglyceride (TG), alanine aminotransferase (ALT) and insulin in boys, whereas only waist girth and WHR/Ht SDS showed a close correlation with TG and insulin in girls. The obese subjects were subdivided according to the number of abnormal values observed in TG, ALT and insulin. For obese boys, all five indices of obesity were higher in the groups with complications than in the group without. In the girls, only the WHR/Ht SDS constantly differed between subgroups. WHR/Ht SDS most obviously distinguished the groups with complications from the other group with a wide margin of difference (2-fold in boys and > 2-fold in girls) in the mean values. CONCLUSION: The WHR/Ht SDS can serve as an index predicting the occurrence of biochemical complications in obese children ranging from the age of 6-15 y.

Adipose Tissue↗

Replacement of the ascending aorta and aortic valve with a composite graft: operative and long-term results.

The purpose of this study is to analyze our treatment experience on patients with ascending aortic aneurysms, with aortic regurgitation. From January 1974 to December 1995, 49 patients underwent replacement of the aortic valve and ascending aorta with a composite graft, in which primary operation cases were 44 and reoperation ones were 5. The Bentall technique was used in 20 patients, the button technique in 11, the interposition graft technique in 11, and a combination of the interposition graft and button technique in 7. All but one reoperation cases underwent the interposition graft technique. Hospital mortality was 30% for the Bentall technique, and 9.1% for the button technique and 9.1% for the interposition graft technique; there was no hospital mortality in the combination of the interposition graft and button technique. Hospital mortality of interposition graft technique in primary operation cases was 9.1%, and that in reoperation cases was 0%. Hospital mortality in patients underwent from 1974 to 1985 was 30.8%, 27.8% from 1986 to 1991, and 0% from 1992 to 1995. Five late deaths occurred in the Bentall group (35.7%) and one late death in the button technique (9.1%). Not late deaths in the other groups have occurred. In summary, operative mortality in Bentall technique group was higher than that of the other groups. Operative results were improved by the change of operative methods. The interposition graft technique is preferable for patients undergoing reoperation or when tension on the ostial anastomoses may occur. The button technique is best for patients with aortic dissection or inflammation involving the coronary ostia.

Adult↗

Pharmacodynamics and pharmacokinetics of a single oral dose of nitrazepam in healthy volunteers: an interethnic comparative study between Japanese and European volunteers.

Potential interethnic differences in drug disposition and effects between Japanese and white subjects hamper the registration in Japan of medications already used in Western countries. This double-blind, placebo-controlled, crossover study was conducted to compare the pharmacodynamics and pharmacokinetics of a single oral dose of nitrazepam (5 mg) in age- and sex-matched Japanese (n = 8) and white (n = 8) healthy volunteers. The study was performed in centers in Japan and the Netherlands using the same methods and study design. Subjects were individually matched for gender, age, and body stature. Drug effects were measured by means of saccadic and smooth pursuit eye movements and visual analog lines obtained from the scales of Bond and Lader. There were no pharmacokinetic differences between the Japanese and white subjects. Clearance of nitrazepam was 0.91 +/- 0.165 mL/min/kg and 1.17 +/- 0.492 mL/min/kg, and half-life (t1/2) was 22.1 +/- 4.96 hours and 21.5 +/- 7.51 hours for the Japanese and European groups, respectively. Pharmacokinetic parameters showed no significant correlation with age, height, or weight. The average time-effect curves for the different parameters were comparable between groups. Compared with placebo, both groups showed similar significant reductions in average peak velocity and increases in saccadic inaccuracy and reaction time. Visual analog scores showed clear sedation in the white subjects, but insignificant effects in the Japanese subjects. Smooth pursuit did not change significantly in either group. Slope and intercept of the concentration-effect relationships for saccadic peak velocity showed considerable intersubject variability, but no clear differences between groups. The pharmacokinetics and pharmacodynamics of nitrazepam were similar in matched healthy Japanese and white subjects. Interethnic comparative studies are feasible, and provide meaningful information about potential racial differences in disposition and action of drugs. Such studies can form a rational basis for comparative clinical trials.

Administration, Oral↗

[Augmented antitumor activity in combination chemotherapy of nedaplatin with etoposide].

Augmented antitumor activity in combination chemotherapy of Nedaplatin (NDP) or Cisplatin (CDDP) with Etoposide (ETP) against murine and human lung cancer cells was demonstrated. NDP and CDDP were administered once and ETP daily for five days via tail vein. In the mice bearing Lewis lung carcinoma, a combination of NDP and ETP resulted in synergistically enhanced inhibition of tumor growth, and prolonged survival in comparison with either NDP or ETP alone. NDP showed a more potent combination effect with ETP than CDDP did. These effects were also demonstrated in human lung cancer cell lines. Although body weight loss was enhanced by the combination of NDP or CDDP with ETP, it was tolerable, and no significant difference between NDP plus ETP and CDDP plus ETP was observed. Thrombocytopenia was not enhanced in the combined treatment of NDP with ETP. These results suggest the usefulness of the combination of NDP with ETP as a clinical therapy for lung cancer.

Animals↗

Repair of (6-4) photoproducts in cultured goldfish cells at confluence or treated with H2O2.

Previously we reported that fluorescent light (FL) illumination prior to UV irradiation (FL preillumination) had multiple effects on the repair of cyclobutane pyrimidine dimers (CPD) and (6-4) photoproducts ([6-4] PD) in cultured goldfish cells (RBCF-1) at the exponentially growing phase. In this study, it is shown that even under the confluent condition of RBCF-1 cells, FL preillumination increased the disappearance of (6-4) PD in the dark. In addition, both at confluence and at the exponentially growing phase, the disappearance of (6-4) PD after PR treatment was increased by FL preillumination to RBCF-1 cells. Moreover, it was found that H2O2 pretreatment, followed by UV irradiation, of the exponentially growing cells also enhanced the disappearance of (6-4) PD in the dark and by photorepair treatment. The degree of enhancement by H2O2 pretreatment was almost the same as that by FL preillumination.

Animals↗

[Augmented antitumor efficacy of combination chemotherapy of nedaplatin with 5-fluorouracil in in vivo murine and human tumor model].

Augmented antitumor activity was demonstrated in combination chemotherapy of Nedaplatin (NDP) or Cisplatin (CDDP) with 5-fluorouracil (5-FU) against murine lung carcinoma and human squamous carcinoma from head and neck. Either NDP or CDDP (1/4 to 1 maximum tolerated dose; MTD) was injected once and 5-FU (1/16 MTD) was injected daily for five days via tail vein to tumor-implanted mice. The sequential administration of either NDP or CDDP prior to 5-FU (NF or CF therapy) showed severe body weight loss followed by the toxic death of tumor-bearing mice at the MTD of NDP or CDDP. In contrast, the reverse sequence of the treatment, that is, 5-FU prior to NDP or CDDP (FN or FC therapy), resulted in the synergistically enhanced inhibition of tumor growth and the prolonged survival in comparison with NDP, CDDP or 5-FU monotherapy. The antitumor activities of the combinations of CDDP with 5-FU was less than those of the combination of NDP with 5-FU. Especially, at the MTD of NDP in FN therapy, long-term tumor-free survival was frequently observed. Thus, FN therapy was thought to be the most efficient regimen in combination of NDP with 5-FU as a clinical therapy.

Animals↗