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Biomedical subjects

K Matsui

Publications and source records attributed to K Matsui.

At least 109 records · Page 6Linked to original sources

IL-12 synergizes with IL-18 or IL-1beta for IFN-gamma production from human T cells.

IL-18 is a proinflammatory cytokine that plays an important role in NK cell activation and T(h)1 response. IL-18 has a structural homology to IL-1, particularly IL-1beta. IL-18R, composed of IL-1R-related protein (IL-18Ralpha) and IL-1R accessory protein-like (IL-18Rbeta), belongs to the IL-1R family. Furthermore, IL-18R at least partly shares the signal transducing system with IL-1R. Thus, the IL-18-IL-18R system has a striking similarity to the IL-1-IL-1R system. For this reason, we regarded it important to investigate whether, like IL-18, IL-1beta synergizes with IL-12 in inducing IFN-gamma production from human T cells and plays an important role in the T(h)1 response. Here we show that IL-12 and IL-1beta synergistically induce T cells to proliferate and produce IFN-gamma without their TCR engagement. IL-12 stimulation induced an increase in the proportion of T cells positive for IL-18R. Then, IL-12-stimulated T cells responded to IL-18 or IL-1beta by their proliferation and IFN-gamma production, although levels of IL-1beta-induced responses were lower. CD4(+)CD45RA(+) T cells, although they constitutively expressed IL-18Rbeta mRNA, did not express IL-18Ralpha mRNA. Phytohemagglutinin (PHA) stimulation alone induced IL-18Ralpha mRNA without affecting the expression of IL-18Rbeta mRNA. T(h)1-inducing conditions (PHA, IL-12 and anti-IL-4) further increased this expression. We also show that T(h)1 cells but not T(h)2 cells have increased expression of IL-18R and IL-1R, and produce IFN-gamma in response to IL-18 and/or IL-1beta.

Drug Synergism↗

Phase II trial of daily low-dose carboplatin and thoracic radiotherapy in elderly patients with locally advanced non-small cell lung cancer.

BACKGROUND: The purpose of this study was to investigate the feasibility of concurrent thoracic radiotherapy (TRT) and daily low-dose carboplatin (CBDCA) in elderly patients with locally advanced non-small cell lung cancer (NSCLC) and to estimate tumor response, toxicity and survival. METHODS: Forty patients were entered in a multicenter phase II study. All were patients with pathologically documented unresectable stage IIIA or IIIB or medically inoperable stage I, II NSCLC. CBDCA 30 mg/m2 was given on days 1-5 in weeks 1-4 concurrently with TRT, mainly for radiosensitization. TRT was started 1 h after CBDCA (30 min infusion) was given. TRT was given in 2 Gy/fraction/day, 5 days a week for a total of 50-60Gy. RESULTS: Thirty-eight patients were assessable for treatment response and toxicity. One patient had a CR and 18 patients PRs with a response rate of 50% (95% CI, 33.4-66.6%). The main toxicities were hematological toxicity. Other toxicities were grade > or =2 esophagitis in one patient, grade 3 nausea/vomiting in one and grade > or =3 pulmonary toxicity in two. There was one treatment-related death due to pulmonary toxicity. For stage IIIA + IIIB patients, the median survival time was 15.1 months and 1-and 2-year actuarial survival rates were 52.6 and 20.5%, respectively. For stage I + II patients, 1- and 3-year actuarial survival rates were 90.9 and 69.3%, respectively. CONCLUSIONS: The data suggest that TRT with daily low-dose CBDCA in elderly patients is effective and feasible because of its low toxicity and survival.

Age Factors↗

Severe proteinuria, sustained for 6 months, induces tubular epithelial cell injury and cell infiltration in rats but not progressive interstitial fibrosis.

BACKGROUND: Sustained proteinuria is reported to be very harmful to the tubulointerstitium, leading to severe interstitial injury. However, it remains unclear whether sustained proteinuria itself is responsible for severe interstitial injury because, in the previously reported models, the development of factors other than proteinuria in tubulointerstitial lesions could not be excluded completely. METHODS: After treatment to induce immune tolerance to mouse immunoglobulin, 20 rats were injected with anti-rat slit diaphragm monoclonal antibody (mAb) 5-1-6 twice a week for 6 months and were then sacrificed. RESULTS: mAb 5-1-6 induced massive proteinuria in 11 rats. In nine rats with mild proteinuria, no histological alteration could be detected with light microscopy and immunofluorescence. In nephrotic rats, light microscopy showed minor glomerular abnormalities, with interstitial oedema, tubular epithelial cell degeneration and interstitial cell infiltration. Immunofluorescence revealed increased expression of vimentin and an increased number of OX1-, OX19- and ED1-positive cells. However, we could not detect any accumulation of type I and IV collagen or laminin in the tubulointerstitium. RT-PCR showed that the expression of mRNA for type I collagen was not increased, compared with that in control rats. CONCLUSIONS: We succeeded in developing a model of persistent nephrosis without severe glomerular abnormalities, nephrectomy or other manoeuvres known to induce disturbed haemodynamics, using an agent without tubulointerstitial toxicity, and considered it to be suitable for investigating the direct toxicity of proteinuria. In this model, isolated massive proteinuria induced interstitial injury. However, the degree of injury was suggested to be much less than that observed in other previously developed models.

Animals↗

Idiopathic nonspecific interstitial pneumonia: prognostic significance of cellular and fibrosing patterns: survival comparison with usual interstitial pneumonia and desquamative interstitial pneumonia.

Nonspecific interstitial pneumonia (NSIP) has been proposed as a histologic subtype of idiopathic interstitial pneumonia with lung biopsy findings that are inconsistent with those of other idiopathic interstitial pneumonias. NSIP has a broad spectrum of histologic findings and a variable prognosis. The aim of this study was to determine whether it would be preferable to subdivide NSIP into cellular and fibrosing patterns. The authors classified lung biopsies from 101 patients with idiopathic interstitial lung disease as having histologic patterns of desquamative interstitial pneumonia (DIP), usual interstitial pneumonia (UIP), or cellular or fibrosing NSIP. Survival analysis was performed using the Kaplan-Meier method. Due to histologic, clinical, and survival similarities, the patients with idiopathic NSIP with lung biopsies that showed fibrosing as well as fibrosing and cellular patterns were combined into a single group of NSIP, fibrosing pattern. Of the 101 patients, 16 patients (9 women, 7 men) had idiopathic DIP; 56 patients (17 women, 39 men) had idiopathic UIP; 22 patients (7 women, 15 men) had idiopathic NSIP, fibrosing pattern; and 7 patients (2 women, 5 men) had idiopathic NSIP, cellular pattern. The patients had a mean age of 42, 51, 50, and 39 years respectively. Patients with idiopathic NSIP, cellular pattern had a better 5- and 10-year survival than those with idiopathic NSIP, fibrosing pattern (100% vs 90% and 100% vs 35% respectively, p = 0.027). Survival of patients with idiopathic UIP was worse than that of patients with idiopathic NSIP, fibrosing pattern (p = 0.014). The difference, however, was more evident at 5 years (43% vs 90%) than at 10 years (15% vs 35%). The 5- and 10-year survival of patients with idiopathic NSIP, cellular pattern and DIP was 100%, which was significantly better than that of patients with idiopathic UIP (p <0.0001). Based on these data, NSIP should be separated into cellular and fibrosing patterns, because these histologic patterns are associated with different clinical characteristics and prognoses.

Adult↗

SM-20550, a new Na+/H+ exchange inhibitor and its cardioprotective effect in ischemic/reperfused isolated rat hearts by preventing Ca2+-overload.

We investigated the effect of a newly synthesized compound, SM-20550 [N-(aminoiminomethyl)-1,4-dimethyl-1H-indole-2-carboxamide methanesulfonic acid] on Na+/H+ or Na+/Ca2+ exchange activity in rat cardiomyocytes, and on radioligand binding with several channels or receptors in membrane preparations, and ischemia/reperfusion injury in isolated perfused rat hearts. In myocytes, SM-20550 concentration-dependently inhibited the recovery from acidosis induced by an NH4Cl prepulse in HCO3(-)-free solution. Its IC50 was 10(-8) M, which was 10 times lower than that of ethylisopropyl amiloride (EIPA). SM-20550 (10(-6) M) did not affect the Na+-dependent Ca2+ influx (Na+/Ca2+ exchange activity) in cardiomyocytes. In the radioligand binding assay, SM-20550 did not have affinity for K+ channel, beta-adrenoceptor, adenosine, angiotensin, or endothelin receptors, and had low affinity for Na+ and Ca2+ channels and alpha-adrenoceptors, only at the concentrations of 10(-6)-10(-5) M. In perfused hearts exposed to 40 min of global ischemia and 20 min of reperfusion, SM-20550 (10(-8)-10(-7) M) significantly reduced the elevation of left ventricular end-diastolic pressure during reperfusion, improved the postischemic recovery of developed pressure, and prevented coronary perfusion pressure increase after reperfusion. Furthermore, SM-20550 reduced creatine phosphokinase release during reperfusion and prevented the abnormal gain of tissue Na+ and Ca2+ at the end of reperfusion. These results suggest that SM-20550 is a potent, highly specific Na+/H+ exchange inhibitor, which exerts a protective effect against myocardial ischemia/reperfusion injury. In addition, our data strongly support the hypothesis that Na+/H+ exchange plays an important role in the development of postischemic cardiac dysfunction, most likely by inducing Na+ and Ca2+ overload.

Amidines↗

Macular buckling for retinal detachment due to macular hole in highly myopic eyes with posterior staphyloma.

PURPOSE: To evaluate the efficacy of macular buckling surgery using a special exoplant. METHODS: The authors reviewed 33 cases of patients with retinal detachment due to macular hole with posterior staphyloma who underwent a macular bucking procedure and 11 cases of patients with the same condition due to macular hole without posterior staphyloma or due to a hole along the edge of the posterior staphyloma who underwent gas injection or vitrectomy. The reattachment rate, visual acuity (VA), and area size (V-4, I-4 isopter) by Goldmann perimetry were calculated. RESULTS: Reattachment rate for the macular buckling procedure was 94% (initial) and 100% (final), and that for the gas injection or vitrectomy was 100% (both initial and final). Twenty of the 33 eyes (60.6%) had VA of 20/400 or better, and none of these 33 eyes had a VA at the level of finger counting or poorer following macular buckling. Nine of the 11 eyes (81.8%) had VA of 20/400 or better, and none of these 11 eyes had a VA at the level of finger counting or poorer following the gas injection or vitrectomy. The area size of V-4 isopter in the macular buckling group was significantly larger than that in the gas injection or vitrectomy group (P = 0.017). CONCLUSION: The macular buckling procedure is effective when considered both from an anatomic and a functional perspective for retinal detachment due to macular hole with posterior staphyloma.

Aged↗

Comparative study of Staphylococcus aureus isolated from lesional and non-lesional skin of atopic dermatitis patients.

The skin of patients with atopic dermatitis (AD) is often colonized by Staphylococcus aureus, and superantigenic exotoxins produced by the organism are thought to be an important precipitating factor of AD. However, there are few reports comparing the characteristics of S. aureus isolated from the lesional and non-lesional skin of identical AD patients. In this study, therefore, we examined whether the presence of superantigen-producing S. aureus correlates with the formation of eczematous lesion of AD patients. The detection rate of S. aureus on the lesional skin of AD patients was higher than on the non-lesional skin of AD patients. Furthermore, the bacterial cell count of S. aureus on the lesional skin of AD patients was also significantly higher than that of the non-lesional skin of AD patients. However, there was no significant difference between the detection rate of superantigenic exotoxin-producing S. aureus on the lesional and nonlesional skin of AD patients. These results suggest that the number of S. aureus present is more important in the formation of eczematous lesion of AD patients than the presence of superantigenic exotoxin-producing S. aureus strains per se.

Adolescent↗

Specific immune response to a synthetic peptide derived from outer surface protein C of Borrelia burgdorferi predicts protective borreliacidal antibodies.

In a previous study, we described the development of a new specific serodiagnostic test for Lyme disease involving enzyme-linked immunosorbent assay and a synthetic peptide, OspC-I. The OspC-I peptide is derived from part of the outer surface protein C (OspC) amino acid sequence of Borrelia burgdorferi and is located in the region conserved among B. burgdorferi sensu stricto or sensu lato isolates. In this study, we demonstrate that sera containing antibodies against OspC-I from patients with early Lyme disease had borreliacidal activity against isolates of three genospecies of Lyme disease spirochete, B. burgdoreferi B31, B. garinii HPI and B. afzelii HT61. However, the borreliacidal activity against B. burgdorferi, which has not been isolated in Japan, was weaker than that against the other species. Vaccination of mice with OspC-I induced the production of anti-OspC-I antibodies in serum with borreliacidal activity. The immune mouse serum had significantly higher levels of borreliacidal activity against HP1 and HT61, than against B31. Neutralization of borreliacidal activity with anti-IgM antibodies showed that the borreliacidal activity of anti-OspC-I antibodies in serum was due to IgM. Furthermore. mice vaccinated with OspC-I were protected against challenge with HPI and HT61. but not fully protected against infection with B31. These results suggest that OspC-I is not only a specific antigen for use in serodiagnostic tests for Lyme disease, but is also a potential candidate for a Lyme disease vaccine in Japan.

Animals↗

Downregulation of estrogen and progesterone receptors in the abnormal smooth muscle cells in pulmonary lymphangioleiomyomatosis following therapy. An immunohistochemical study.

Immunohistochemical and confocal microscopic studies were made on lung tissue from 10 women with lymphangioleiomyomatosis (LAM) to evaluate the distribution of estrogen receptors (ER) and progesterone receptors (PR) in the abnormal smooth muscle cells (LAM cells) that characterize this disorder. PR and ER were localized mainly in the nuclei of large, epithelioid LAM cells, in five patients in whom tissues were obtained before treatment. However, the reaction for PR and ER was essentially negative in similarly processed tissues from five patients studied after receiving hormonal therapy (progesterone and tamoxifen). In the untreated group, staining for ER and PR colocalized with that for HMB-45, but not with that for membrane type-1 matrix metalloproteinase (MT-1-MMP), which we have shown to be localized in proliferating LAM cells. These observations demonstrate that PR and ER are selectively expressed in a subpopulation of LAM cells that are larger in size, have a limited ability to proliferate, and do not produce MT-1-MMP, the enzyme that activates MMP-2 (which is secreted by LAM cells and is capable of lysing elastin and collagens). ER and PR in LAM cells appear to be downregulated by hormonal therapy.

Adult↗

Transplanted cord blood-derived endothelial precursor cells augment postnatal neovascularization.

Endothelial precursor cells (EPCs) have been identified in adult peripheral blood. We examined whether EPCs could be isolated from umbilical cord blood, a rich source for hematopoietic progenitors, and whether in vivo transplantation of EPCs could modulate postnatal neovascularization. Numerous cell clusters, spindle-shaped and attaching (AT) cells, and cord-like structures developed from culture of cord blood mononuclear cells (MNCs). Fluorescence-trace experiments revealed that cell clusters, AT cells, and cord-like structures predominantly were derived from CD34-positive MNCs (MNC(CD34+)). AT cells and cell clusters could be generated more efficiently from cord blood MNCs than from adult peripheral blood MNCs. AT cells incorporated acetylated-LDL, released nitric oxide, and expressed KDR, VE-cadherin, CD31, and von Willebrand factor but not CD45. Locally transplanted AT cells survived and participated in capillary networks in the ischemic tissues of immunodeficient nude rats in vivo. AT cells thus had multiple endothelial phenotypes and were defined as a major population of EPCs. Furthermore, laser Doppler and immunohistochemical analyses revealed that EPC transplantation quantitatively augmented neovascularization and blood flow in the ischemic hindlimb. In conclusion, umbilical cord blood is a valuable source of EPCs, and transplantation of cord blood-derived EPCs represents a promising strategy for modulating postnatal neovascularization.

Animals↗

[Hepatotoxicity induction in mice after acute DL-lactic acid intake].

DL-Lactic acid and its salts are added to food as acidulants, pH control agents, leavening agents, nutrient supplements and seasonings. However, the basic data concerning the safety and toxicity of these compounds are insufficient. In this article, we examined induction of hepatotoxicity and nephrotoxicity in mice after acute intake of DL-lactic acid. Body weight change, serum glutamic pyruvic transaminase (SGPT) activity, serum urea nitrogen (SUN) concentration, liver and kidney weights, and renal lipid peroxide level could not be affected significantly in mice at 4 h after intraperitoneal administration of DL-lactic acid at 1.2 mmol/kg, indicating no induction of toxicity in the liver and kidney. In contrast, at 20 h after the treatment, SGPT activity, liver weight and lipid peroxide level were enhanced significantly, suggesting induction of hepatotoxicity. However, SUN concentration, kidney weight and lipid peroxide level could not be affected significantly at 20 h after the treatment, indicating no induction of nephrotoxicity.

Administration, Oral↗

Effect of SMP-300, a new Na+/H+ exchange inhibitor, on myocardial ischemia and experimental angina models in rats.

We evaluated the effects of SMP-300 (N-(aminoiminomethyl)-11-chloro-5,6,7,8-tetrahydro-8-oxo-4H-pyrrolo[3,2,1-kl][1]benzazocine-2-carboxamide monomethanesulfonate monohydrate), a newly synthesized compound, on Na+/H+ exchange activity in rat cardiomyocytes and on other ion transporters, channels and receptors. We also investigated the protective effects of SMP-300 in isolated ischemic rat hearts and rat isoproterenol- or vasopressin-induced experimental angina models. SMP-300 concentration-dependently inhibited recovery from acidosis in rat myocytes, and its IC50 for Na+/H+ exchange was 6 nM. In comparison, its IC50s for Na+/Ca2+ exchange and for the Na+ channel were >1000 nM, and those for other channels or receptors tested were >10,000 nM. In rat isolated perfused hearts, SMP-300 (10(-8)-10(-7) M), administered only at preischemia and not during reperfusion, significantly improved the postischemic recovery of cardiac function. SMP-300 (0.03-0.3 mg/kg, i.v.) or 5-(N-ethyl-N-isopropyl)-amiloride (1 mg/kg, i.v.) prevented the isoproterenol-induced ST-segment depression in the ECG of anesthetized rats, in a dose-dependent manner. SMP-300 (0.1 mg/kg, i.v.) and 5-(N-ethyl-N-isopropyl)-amiloride (1 mg/kg, i.v.) also inhibited the vasopressin-induced ST-segment depression in the ECG of anesthetized rats. This is the first report presenting the protective effect of Na+/H+ exchange inhibitors on isoproterenol- or vasopressin-induced ECG changes in rats, providing the future perspective of SMP-300, a potent Na+/H+ exchange inhibitor, as an anti-anginal drug.

Amiloride↗

Fatty acid hydroperoxide lyase in tomato fruits: cloning and properties of a recombinant enzyme expressed in Escherichia coli.

Fatty acid hydroperoxide lyase (HPL) is a member of a novel subfamily of cytochrome P450 and catalyzes a cleavage reaction of fatty acid hydroperoxides to form short-chain aldehydes and oxo-acids. A cDNA encoding tomato fruit HPL (LeHPL) was obtained. An active LeHPL was expressed in E. coli and purified. It showed highest activity against the 13-hydroperoxide of linolenic acid, followed by that of linoleic acid. 9-Hydroperoxides were poor substrates. The absorption spectrum of the purified LeHPL in the native form was similar to that of most P450s although a CO-adduct having a lambda max at 450 nm could not be obtained. LeHPL activity is reversibly inhibited by nordihydroguaiaretic acid, while salicylic acid irreversibly inhibited it. LeHPL is kinetically inactivated by fatty acid hydroperoxides, especially 9-hydroperoxides. The inactivation is prevented by inhibitors of LeHPL. Thus, HPL catalytic activity is thought to be essential to its inactivation. During the inactivation, an abolition of the Soret band was evident, indicating that inactivation is caused mainly by degradation of the prosthetic heme in LeHPL.

Aldehyde-Lyases↗

Lymphangioleiomyomatosis (LAM): a review of clinical and morphological features.

A review is presented of the clinical and morphological manifestations of lymphangioleiomyomatosis (LAM), a systemic disorder of unknown etiology that affects women. The clinical features include dyspnea, hemoptysis, recurrent pneumothorax, chylothorax, and chylous ascites. It is characterized by: 1) proliferation of abnormal smooth muscle cells (LAM cells) in pulmonary interstitium and along the axial lymphatics of the thorax and abdomen; 2) thin-walled pulmonary cysts, and 3) a high incidence of angiomyolipomas. The pulmonary cystic lesions have a characteristic appearance on high resolution computed tomography. The most specific method for diagnosing LAM is lung biopsy to demonstrate the presence of LAM cells, either by their characteristic histological appearance or by specific immunostaining with HMB-45 antibody. LAM cells differ in several important respects from the types of smooth muscle cells normally present in lung. Their reactivity with HMB-45 antibody is localized in stage I and stage II melanosomes. LAM cells show additional evidence of incomplete melanogenesis, and the significance of these observations remains to be determined. Two types of LAM cells are recognized: 1) small, spindle-shaped cells that are centrally located in the LAM nodules and are highly immunoreactive for matrix metalloproteinase-2 (MMP-2), its activating enzyme (MT-1-MMP), and proliferating cell nuclear antigen (PCNA), and 2) large, epithelioid cells that are distributed along the periphery of the nodules and show a high degree of immunoreactivity with HMB-45 antibody and with antibodies against estrogen and progesterone receptors. Types of treatment used for LAM include oophorectomy, administration of Lupron or progesterone and in very severe cases, pulmonary transplantation (following the onset of respiratory insufficiency, not relieved by O(2)).

Antibodies, Neoplasm↗

Role for activation of matrix metalloproteinases in the pathogenesis of pulmonary lymphangioleiomyomatosis.

BACKGROUND: Matrix metalloproteinases (MMPs) have been shown to be involved in the pathogenesis of the destructive pulmonary lesions in patients with lymphangioleiomyomatosis (LAM); in the present report, the activation of these enzymes is examined. OBJECTIVE: To evaluate the role of MMPs and their activating enzymes, immunohistochemical and confocalmicroscopic techniques were used to localize alpha-smooth muscle actin (alpha-SMA), HMB-45, proliferating cell nuclear antigen (PCNA), MMP-2, membrane-type 1 MMP (MT1-MMP), MT2-MMP, and MT3-MMP in lung tissues from 10 women with LAM. Tissue samples were obtained from 5 patients before treatment and in 5 patients after hormone treatment (progesterone and/or tamoxifen citrate). RESULTS: Staining for alpha-SMA and MMP-2 was present in all the abnormal smooth muscle cells (LAM cells) in both groups. The percentages of PCNA-, MMP-2-, or MT1-MMP-positive LAM cells were much higher in the untreated group than in the treated group, whereas the percentages of HMB-45-reactive LAM cells were similar in both groups. The reactions for MT1-MMP and PCNA were preferentially localized in small spindle-shaped LAM cells; the reaction for HMB-45 was found in large epithelioid LAM cells. Many of the PCNA-positive cells were also positive for MT1-MMP. Staining for MT2-MMP and MT3-MMP was negative. CONCLUSIONS: This study demonstrates an association between cellular proliferation and the presence of MT1-MMP in LAM cells. The activation of MMP-2 by MT1-MMP may play an important role in the destruction of lung tissue in this disorder.

Actins↗

Hyperplasia of type II pneumocytes in pulmonary lymphangioleiomyomatosis.

BACKGROUND: Little is known of the morphology of the pneumocytes lining the parenchymal cysts in lymphangioleiomyomatosis (LAM). OBJECTIVE: To evaluate the structural characteristics of the alveolar epithelial cells in LAM. METHODS: Immunohistochemical and electron microscopic studies were performed on lung tissue from 22 women with pulmonary LAM. RESULTS: Epithelial cells that reacted with PE-10 (a mouse monoclonal antibody that recognizes the surfactant apoprotein A in type II pneumocytes) and TTF-1 (an antibody that identifies nuclear transcription factor found in type II pneumocytes) were the predominant cell type lining the surfaces of lesions of LAM and normal areas of lung. Scanning and transmission electron microscopic studies confirmed that these cells were type II pneumocytes as demonstrated by (1) apical microvilli, (2) electron-dense lamellar bodies, and (3) cytoplasmic projections that extended from the basal surfaces into the underlying connective tissue, where they made extensive contact with interstitial connective tissue cells. A few cells had morphologic characteristics of type I pneumocytes, including large flat surfaces lacking microvilli. Cells that appeared intermediate between type I and type II pneumocytes were observed occasionally. CONCLUSIONS: These observations and the reactivity of these cells with antibody to proliferating cell nuclear antigen demonstrate that extensive hyperplasia of type II pneumocytes is a major characteristic of LAM.

Adult↗

Phase I trial of oral 2'-deoxy-2'-methylidenecytidine: on a daily x 14-day schedule.

2'-deoxy-2'-methylidenecytidine (DMDC) is a potent deoxycytidine analogue. Preclinical studies of DMDC demonstrated activity against a variety of murine and human tumors in cell cultures and murine models and indicate enhanced antitumor activity of DMDC when it was administered in a manner that provided prolonged systemic exposure. In view of this observation, this study was designed to determine the toxicities, maximum-tolerated dose, and pharmacokinetic profile of DMDC. DMDC was given p.o. under fasting conditions for 14 consecutive days every 4 weeks in patients with advanced solid tumors. The starting dose was 12 mg/m2/day. Pharmacokinetic studies were carried out on days 1 and 14 of the first cycle. Fourteen patients received 22 courses of DMDC. The dose-limiting toxicities were anorexia, leukopenia, thrombocytopenia, and anemia. General fatigue was the common nonhematological toxicity. The maximum-tolerated dose was 18 mg/m2/day, at which two of six patients developed grade 3 toxicities. This dose level could also be considered for Phase II testing with this schedule. At the 18-mg/m2/day dose level, the mean terminal half-life, maximum plasma concentration (Cmax), the area under the plasma drug concentration-time curve (AUC(0-infinity)) on day 1 were 1.7496 h, 112.9 ng/ml, and 399.8 ng x h/ml, respectively. Forty to 50% of the administered dose was recovered in the urine, indicating a good bioavailability and resulting significant systemic exposure to the drug, which may enable chronic oral treatment.

Adenocarcinoma↗