Impact of brown adipose tissue on body fatness and glucose metabolism in healthy humans.

BACKGROUND: Brown adipose tissue (BAT) is involved in the regulation of whole-body energy expenditure and adiposity. Some clinical studies have reported an association between BAT and blood glucose in humans. OBJECTIVE: To examine the impact of BAT on glucose metabolism, independent of that of body fatness, age and sex in healthy adult humans. METHODS: Two hundred and sixty healthy volunteers (184 males and 76 females, 20-72 years old) underwent fluorodeoxyglucose-positron emission tomography and computed tomography after 2 h of cold exposure to assess maximal BAT activity. Blood parameters including glucose, HbA1c and low-density lipoprotein (LDL)/high-density lipoprotein-cholesterol were measured by conventional methods, and body fatness was estimated from body mass index (BMI), body fat mass and abdominal fat area. The impact of BAT on body fatness and blood parameters was determined by logistic regression with the use of univariate and multivariate models. RESULTS: Cold-activated BAT was detected in 125 (48%) out of 260 subjects. When compared with subjects without detectable BAT, those with detectable BAT were younger and showed lower adiposity-related parameters such as the BMI, body fat mass and abdominal fat area. Although blood parameters were within the normal range in the two subject groups, HbA1c, total cholesterol and LDL-cholesterol were significantly lower in the BAT-positive group. Blood glucose also tended to be lower in the BAT-positive group. Logistic regression demonstrated that BAT, in addition to age and sex, was independently associated with BMI, body fat mass, and abdominal visceral and subcutaneous fat areas. For blood parameters, multivariate analysis after adjustment for age, sex and body fatness revealed that BAT was a significantly independent determinant of glucose and HbA1c. CONCLUSION: BAT, independent of age, sex and body fatness, has a significant impact on glucose metabolism in adult healthy humans.

Impact of UCP1 and ß3AR gene polymorphisms on age-related changes in brown adipose tissue and adiposity in humans.

BACKGROUND: Brown adipose tissue (BAT) is involved in the regulation of whole-body energy expenditure and adiposity. The activity and prevalence of BAT decrease with age in humans. OBJECTIVE: To examine the effects of single nucleotide polymorphisms of the genes for uncoupling protein 1 (UCP1) and ß3-adrenergic receptor (ß3AR), key molecules of BAT thermogenesis, on age-related decline of BAT activity and accumulation of body fat in humans. METHODS: One hundred ninety-nine healthy volunteers (20-72 years old (y.o.)) underwent fluorodeoxyglucose-positron emission tomography (FDG-PET) and computed tomography (CT) after 2-h cold exposure to assess BAT activity. The visceral and subcutaneous fat areas at the abdominal level were estimated from the CT images. They were genotyped for -3826 A/G polymorphism of the UCP1 gene and 64 Trp/Arg mutation of the ß3AR gene. RESULTS: BAT was detected in 88 subjects out of 199 (44%), more in younger (30 y.o., 55%) than older subjects (>40 y.o., 15%). BAT prevalence of older subjects tended to be lower in the UCP1 G/G group than the A allele group (A/A and A/G), and also in the ß3AR Arg allele group (Trp/Arg and Arg/Arg) than the Trp/Trp group. When compared subjects who had two or more base substitutions on the two genes (the 2-4 allele group) with those who had less than two base substitutions (the 0-1 allele group), BAT prevalence was comparable in younger subjects (62% vs 50%) but lower in older subjects (0% vs 24%, P<0.05). Visceral fat area of the 2-4 allele group was higher than that of the 0-1 allele group (P<0.05) in older subjects, but not in younger subjects. CONCLUSION: UCP1 -3826 A/G and ß3AR 64 Trp/Arg substitutions accelerate age-related decrease in BAT activity, and thereby may associate with visceral fat accumulation with age.

Quantification of umu genotoxicity level of urban river water.

In recent years, the request of environmental safety management for carcinogenic substances, mutagenic substances and/or reproductive toxicity substances (CMR) has increased. This study focused on clarifying the genotoxicity level of environmental water and its release source by using the umu test provided in ISO13829. Although a genotoxicity index "induction ratio (IR)" is used in ISO13829, we normalised it to make it possible to compare various environmental water quantitatively to each other as a new index "genotoxic activity (GA=(IR-1)/Dose)". Sample water was collected and concentrated to 100 times or 1,000 times by a solid phase extraction method. As the test results, it was found that GA level in actual river water varied widely from less than the determination limit of 23 [1/L] to 1,100 [1/L] by quantitative comparison, and the value was also equivalent to more than 50 times the level of tap water. The GA level of household wastewater was not so high, but the levels of treated water from wastewater treatment plant (WTP) were from 220 [1/L] to 3,200 [1/L]. Raw sewage of some WTP shows high level genotoxicity. A part of genotoxicity substances, for example 50%, could be removed by conventional wastewater treatment, but it was not enough to reduce the water environmental load of genotoxicity.

Chlorination by-products of fenitrothion.

The mutagens produced through chemical reaction between chlorine and the insecticide fenitrothion were studied by using a quadrupole GC-MS. The mutagenicity and the mutagen formation potential (MFP) of the identified by-products were evaluated by the Ames assay (preincubation method) using Salmonella typhimurium TA100 without exogenous activation by S9 mix (TA100-S9). Before conducting GC/MS analyses, six compounds were presumed to be produced in chlorinated fenitrothion. These compounds were confirmed to be produced by the GC/MS analyses, but none of them were mutagenic. One of the chlorination by-products, 3-methyl-4-nitrophenol, has 19 times greater MFP than that of fenitrothion. This result suggests that a major mutagen in chlorinated fenitrothion will be produced via a chemical reaction between chlorine and 3-methyl-4-nitrophenol.

Large cell neuroendocrine carcinoma of the tongue base: case report of an unusual location with immunohistochemical analysis.

A case of large cell neuroendocrine carcinoma (LCNEC) of the tongue base is described. It was characterized by solid tumor nests with central necrosis and rosette formation resembling basaloid squamous cell carcinoma. Immunohistochemical examination revealed that this tumor had neuroendocrine differentiation. It was diagnosed as LCNEC of the tongue base. Pulmonary LCNEC is a well-established entity, but LCNEC also occurs in other organs. This is the first report of mucosal LCNEC in the oral cavity. Basal cells in the normal squamous epithelium around the tumor indicated positivity for neural cell adhesion molecule and N-cadherin. These cells were considered neuroendocrine-related cells in the lingual squamous epithelium, which are related to the tumorigenesis of mucosal LCNEC in the tongue base.

A larval medaka (Oryzias latipes) acute toxicity assay combined with solid-phase extraction to efficiently determine the toxicity of organic contaminants in river water.

Using a larval medaka (Oryzias latipes) acute toxicity assay combined with solid-phase extraction, we proposed a method for efficiently determining the fish toxicity of organic contaminants in river water. Organic toxicants were 10, 20, 50 and 100-fold concentrated from 4 L of the sample with adsorption cartridges. The lethal effect was observed by exposing every ten individuals of 48-72 h old larval medaka to 20 mL of each solution for 48h. The median lethal concentration rate (LCR50) was used as an indicator for the toxicity. With the developed toxicity test method, more than seven times difference was found in the LCR50 of the river water samples. LCR50 distribution profiles were compared with 125 samples in two typical rivers. The result revealed a lower toxicity level in the mainstream than in the confluences, and a lower toxicity level in Sagami River than in Ayase River. LCR50 proved unique as a toxicity indicator, which was impossible to speculate from the conventional water quality indicator of the dissolved organic carbon concentration. As an effective screening test for priority settings, the method can help us with an efficient planning for the environmental investigation and management.

Influence of micrometastasis on N stage in gastric cancer and clinical application.

In order to evaluate the real extent of lymph node metastasis (LNM) in gastric cancer, an immunohistochemical (IHC) analysis was performed. We examined 11173 lymph nodes removed from 355 patients with all stages of gastric carcinoma. Tissue preparations were stained with cytokeratin 18, monoclonal antibody against cytokeratin. Micrometastases were found in 2.5% of the lymph nodes and in 31.3% of patients. The incidence of the patients with LNM increased to 9.1% in T(1m) (n = 99), 31.6% in T(1sm) (n = 95, 23.1% in sm1, 34.8% in sm2), 66.7% in T2 (n = 108, 48.8% in mp, 76.5% in ss), 88.1% in T3 (n = 42), and 90.9% in T4 (n = 11) lesions. Upstage was identified in 8.5% of patients: 6.7% in T1 (4.0% in m, 7.7% in sm1, 10.1% in sm2), 14.8% in T2 (20% in mp, 11.8% in ss), 2.4% in T3, and 0% in T4. Factors related to LNM were: tumor size and lymphatic invasion in mucosal lesions; only lymphatic invasion in submucosal lesions; size and depth of tumor, and lymphatic invasion in T2 lesions. In conclusion, the incidence of micrometastasis in regional lymph nodes was higher than we imagined in T1 lesions, more than D1 lymphadenectomy for sm1 and selected cases of mucosal cancer, and D2 lymphadenectomy for sm2 are necessary.

Expression of AODEF, a B-functional MADS-box gene, in stamens and inner tepals of the dioecious species Asparagus officinalis L.

Garden asparagus (Asparagus officinalis L.) is a dioecious species with male and female flowers on separate unisexual individuals. Since B- and C-functional MADS-box genes specify male and female reproductive organs, it is important to characterize these genes to clarify the mechanism of sex determination in monoecious and dioecious species. In this study, we isolated and characterized AODEF gene, a B-functional gene in the development of male and female flowers of A. officinalis. Southern hybridization identified a single copy of AODEF gene in asparagus genome. Northern blot analysis showed that this gene was specifically expressed in flower buds and not in vegetative tissues. In situ hybridization showed that during early hermaphrodite stages, AODEF gene was expressed in the inner tepal and stamen whorls (whorls 2 and 3, respectively), but not in the outer tepals (whorl 1), in both male and female flowers. In late unisexual developmental stages, the expression of AODEF gene was still detected in the inner tepals and stamens of male flowers, but the expression was reduced in whorls 2 and 3 of female flowers. Our results suggest that AODEF gene is probably not involved in tepal development in asparagus and that the expression of AODEF gene is probably controlled directly or indirectly by sex determination gene in the late developmental stages.

Expression of cyclin A in endometrial adenocarcinoma and its correlation with proliferative activity and clinicopathological variables.

PURPOSE: Cyclin A is known as an S- and G2-M phase regulatory protein and its abnormal expression has been reportedly implicated in cellular proliferation. This study was designed to investigate the correlation of cyclin A expression with tumorigenesis of the endometrium and clinicopathological variables. METHODS: Immunohistochemical staining using labeled streptavidin-biotin complex was performed on formalin-fixed, paraffin-embedded tissue of normal endometrium (15 cases), endometrial hyperplasia (23 cases), and endometrial adenocarcinoma (endometrioid type) (112 cases). RESULTS: Immunohistochemistry showed that the nuclei of the cells were positive for cyclin A. In normal endometrium, only proliferative phase was focally positive for cyclin A. Cyclin A was also positive for endometrial hyperplasia. Its expression in hyperplasia was significantly more frequent than that of proliferative phase and less than that of endometrioid adenocarcinoma. The labeling index (LI) of cyclin A in endometrioid adenocarcinoma was 16.3+/-6.9 in well-differentiated, 18.3+/-8.8 in moderately differentiated, and 30.2+/-11.8 in poorly differentiated adenocarcinoma, respectively. Cyclin A expression increased significantly more in high histological grades. The area of squamous metaplasia in endometrioid adenocarcinoma was negative for cyclin A. The LI of cyclin A was positively correlated with that of Ki-67 and cyclin-dependent kinase 2. Cyclin A expression was significantly associated with carcinoma without coexisting endometrial hyperplasia and lymphovascular space involvement (LVSI), but not with FIGO stage, myometrial invasion, lymph node metastasis, estrogen receptor, progesterone receptor, and menopause as well as recurrence. CONCLUSIONS: Cyclin A expression was involved in the progression to malignancy of the endometrium and was correlated with proliferative activity and prognostic features including histological grade, without coexisting endometrial hyperplasia and LVSI.

Paradoxical expression of cell cycle inhibitor p27 in endometrioid adenocarcinoma of the uterine corpus - correlation with proliferation and clinicopathological parameters.

p27 is regarded as a cyclin-dependent kinase inhibitor of the G1-to-S cell cycle progression by suppressing the kinase activity of cyclin/cyclin-dependent kinase complex. This study aimed to investigate p27 expression in the normal endometrium and endometrioid adenocarcinoma of the uterine corpus and the correlation of its expression with cell proliferation and clinicopathological parameters. Tissue samples of 127 endometrioid adenocarcinomas and 15 normal endometria were used in the study. Immunohistochemical staining for detecting p27 and Ki-67 was performed by the labelled streptavidin-biotin method on formalin-fixed and paraffin-embedded tissue samples. The expression was given as the labelling index, which indicates the percentage of positive nuclei. p27 staining was observed in the nuclei of the glandular cells in the functional layer of the secretory phase endometrium, whereas it was negative in those of the proliferative phase. In endometrioid adenocarcinomas, the labelling index of p27 expression paradoxically increased more significantly in the higher histological grades and was correlated with that of Ki-67. The high level of p27 expression was associated with clinicopathological parameters such as FIGO stage, lymph node metastasis, lymphovascular space involvement and myometrial invasion. High p27 expression was linked to higher grades of endometrioid adenocarcinoma, cell proliferation and some clinical prognostic factors. These results indicate that p27 might be an indicator of poor prognosis.

CDK-inhibitors-associated kinase activity: a possible determinant of malignant potential in smooth muscle tumors of the external soft tissue.

There has been accumulating histological observation of leiomyoma and leiomyosarcoma of the external soft tissue regarding their differential diagnosis. The definitive diagnostic tools have not been established, however, nor have the pathological mechanisms of cell proliferation in these tumors been clarified. Herein, expression of the cyclin-dependent kinase inhibitors (CKIs), p21, p27 and p57 and their associated kinase activities were examined in 61 cases of soft tissue smooth muscle tumors. Immunohistochemical staining showed that all 3 inhibitor proteins were expressed in all cases of leiomyoma and leiomyosarcoma, but that the mean values of their labeling indices (LIs) were higher in the cases of leiomyosarcoma. In addition, the LIs of p21 and p27 were inversely correlated in total cases. Immunoblotting revealed that these proteins are expressed at higher levels in tumors, in particular, in leiomyosarcoma. When CKIs were immunoprecipitated from tissue extracts, cyclin/cdk protein complexes associated with, at least, 1 CKI were detectable only in tumor tissues. Furthermore, cdk2 or cdk4 kinase activity manifested by these cyclin/cdk/CKI complexes (CKI-associated kinase activity) was detectable exclusively from leiomyosarcoma, but not from leiomyoma. Among the cases of leiomyosarcoma, cdk2 activity was generally found associated either with p21 or p27, but not both. Statistical analysis indicated that p21- and p27 LIs are predictive of positive or negative clinical outcome, respectively. In conclusion, the participation of CKIs in active cyclin/cdk complexes in a reciprocal and redundant manner and subsequent CKI- associated kinase activity are the characteristic profiles of malignant phenotype in these tumors. Moreover, immunohistochemical detection of CKIs may provide a useful tool for evaluating patients' prognosis.

The MEN1 gene and associated diseases: an update.

Heterozygous germline mutations of the tumor suppressor gene MEN1 are responsible for multiple endocrine neoplasia type 1 (MEN1), a dominantly inherited familial cancer syndrome characterized by the combined occurrence of pituitary, parathyroid, and enteropancreatic tumors. Various types of mutations likely causing loss of the gene function have been identified throughout the entire gene region in patients with MEN1 and related disorders including a small fraction of familial isolated hyperparathyroidism (FIHP). Neither mutation hot spot nor phenotype-genotype correlation has been established in classical MEN1, although some missense mutations may be specifically associated with a phenotype of FIHP. Familial isolated pituitary tumor and atypical familial MEN1 consisting of only pituitary tumor and hyperparathyroidism usually lack germline MEN1 mutations, suggesting that these familial endocrine tumor syndromes are genetic entities distinct from MEN1. DNA test for MEN1 germline mutations is a robust tool for diagnosis of predisposition to MEN1, and will be useful for the counseling and management of patients and their families. In this review, we will summarize the most recent findings on the MEN1 gene, focusing primarily on germline mutations and associated diseases.

Overexpression of cdk4/cyclin D1 induces apoptosis in PC12 cells in the presence of trophic support.

The induction of apoptosis by cell cycle regulator molecules under conditions optimal for exponential growth was examined in rat pheochromocytoma PC12 cells by overexpression of cyclins and cyclin-dependent kinases (cdks). By flow cytometry and by immunofluorescence, only cells overexpressing cdk4 or cyclin D1 underwent apoptosis, which was not associated with G1-arrest. Cdk4 kinase activity was significantly higher in cdk4-, or cyclin D1-expressing cells. Furthermore, induction of apoptosis by cdk4 was abrogated by co-transfection of p16(INK4), or dominant negative cdk4. These results suggest that upregulation of cdk4 kinase activity is a primary and critical mediator of apoptosis in PC12 cells under physiological conditions.

Hyalinizing spindle cell tumor with giant rosettes: report of a case showing remarkable myofibroblastic differentiation.

We examined the proliferative activity and the differentiation line of tumor cells in a case of "hyalinizing spindle cell tumor with giant rosettes" (HSCGR). A 6 cm tumor within the right deltoid muscle of a 58-year-old female was found by physical and radiographical examinations. A biopsy revealed the histological features of a spindle cell tumor with rosette-like structures. Wide excision was done under the diagnosis of HSCGR. The tumor presented as a gray-whitish, solid mass with focal pseudocystic degeneration. Immunohistochemically, the tumor cells were diffusely positive for vimentin and were also focally positive for S-100, but negative for desmin and alpha-smooth muscle actin. The cells stained positively for Ki-67 with even distribution, there being a correlation with the cellularity of the areas, with a labeling index ranging from 0.3 to 0.5%. In addition, flow cytometry revealed an almost normal diploid DNA pattern and 5.8% S-phase fraction, indicating low proliferative activity. Ultrastructurally, many tumor cells displayed discontinuous basal lamina, pinocytotic vesicles, dilated rough endoplasmic reticulum, and microfilaments with focal dense bodies. The main component of the rosette was collagenous fibrils with normal diameter and normal periodic banding. We interpreted this case of HSCGR as a low grade fibrosarcoma with remarkable differentiation of myofibroblastic lineage, and with focally accumulated, morphologically normal collagenous fibrils.

Antitumor effect of bcl-2 antisense phosphorothioate oligodeoxynucleotides on human renal-cell carcinoma cells in vitro and in mice.

BACKGROUND AND PURPOSE: Programmed cell death is a genetically regulated pathway that is altered in many cancers. This process is, in part, regulated by the bcl-2 oncogene. Antisense oligodeoxynucleotides (ODNs) targeted to specific oncogenes have been used with some therapeutic success in animal models of leukemia and melanoma cells and human Hodgkin's lymphoma. We evaluated the effects of antisense ODNs targeted to the bcl-2 oncogene on the proliferation of human renal-cell carcinoma (RCC) cells in vitro and on the growth of human RCC xenografts in BALBc nude (nu/nu) mice. MATERIALS AND METHODS: Expression bcl-2 mRNA in five RCC cell lines (ACHN, Caki-1, RCZ, RCW, and OS-RC-2) was analyzed by reverse transcriptase-polymerase chain reaction. The effects of phosphorothioated ODNs containing human bcl-2 sense and bcl-2 antisense sequences that were transfected with Lipofectin on the proliferation and viability of cultures of established human RCC cell lines were determined by MTS assay. The expression of Bcl-2 protein in ACHN tumor cells following antisense bcl-2 (AS2) ODN treatment was evaluated by Western blot analysis, and the extent of apoptosis in these cells was determined by fluorescence-activated cell sorter (FACS) analysis. The antitumor activity in ACHN xenografts in nu/nu mice was monitored by measuring differences in tumor weight in treated and control mice. RESULTS: Expression of bcl-2 mRNA was detected in all five RCC lines. Treatment with antisense bcl-2 ODNs inhibited the growth of all tested RCC cells and decreased Bcl-2 protein expression in ACHN cells. The AS2 antisense ODN complementary to the coding region of bcl-2 mRNA showed a superior antiproliferative effect compared with AS1 ODN complementary to the translation initiation region. Inhibition by antisense bcl-2 ODNs of ACHN cells was dose dependent. The FACS analysis revealed that growth inhibition was associated with the induction of programmed cell death. In vivo, AS2 ODN antitumor activity was noted in locally injected groups. CONCLUSIONS: Treatment of human RCC with antisense ODNs targeted to bcl-2 inhibits growth and is associated with the induction of programmed cell death. These results suggest therapeutic use of antisense bcl2 in the treatment of RCC.

Clinicopathologic significance of telomerase activity and hTERT mRNA expression in non-small cell lung cancer.

Telomerase has been reported to be a novel diagnostic marker for malignant diseases and has been recently proven to be composed of three main components, hTR (human telomerase RNA component), TP1 (telomerase-associated protein 1) and hTERT (human telomerase reverse transcriptase), the last of which plays a key role in telomerase activation. In the present study, quantitative levels of telomerase activity and hTERT gene mRNA (hTERT) expression were analyzed in cancerous and non-cancerous lung tissues of 62 lung cancer patients by telomeric repeat amplification protocol and reverse transcription-PCR, respectively. The telomerase expression levels of each group of tissue samples were compared with clinicopathologic variables. Telomerase activity and hTERT were detected in cancerous tissues (75.8 and 75.8%, respectively), while these parameters were not observed in any non-cancerous tissues. In quantitative assessment of telomerase expression, both telomerase activity and hTERT were significantly correlated with lymph node metastasis (N0 vs. N1+2, P<0.05). Telomerase activity also correlated with tumor cell differentiation and stage classification (P<0.05), but did not correlate with other clinicopathologic variables. The disease-free survival in patients with lung cancer demonstrated that patients with hTERT-positive tumor survived for a significantly shorter period than those with hTERT-negative tumor (P=0.0334). Since hTERT levels are correlated with N factor which represents the true aggressiveness of patients' disease concerning the evaluation of clinical outcome, hTERT was found to be one of the important markers revealing biological malignant potentials for lung cancer.

Co-expression of N-cadherin and alpha-fetoprotein in stomach cancer.

Although N-cadherin is necessary for organ formation originating in the endoderm, the expression of N-cadherin in gastric carcinoma and its role has not yet been reported. The present study was conducted to determine the pattern of immunohistochemical expression of E-cadherin and N-cadherin, using formalin-fixed, paraffin-embedded tissues from 97 primary gastric carcinomas, including 17 which were producing alpha-fetoprotein (AFP). Samples were subdivided into 50 tubular adenocarcinomas and 47 poorly differentiated adenocarcinomas. Results showed that E-cadherin was expressed in varying degrees in areas of cell adhesion between tumor cells, in 94 out of 97 cases studied. Three cases which showed no expression of E-cadherin were diagnosed as AFP-producing tumors by immunohistochemistry. Expression of N-cadherin was observed in varying degrees in the intercellular spaces between tumor cells in 11 tubular adenocarcinomas and in six poorly differentiated adenocarcinomas, including E-cadherin-negative cases, all of which were AFP positive. The present findings suggest a possible role for N-cadherin in gastric carcinoma.

A pharmacological study of the weekday-on/weekend-off oral UFT schedule in colorectal cancer patients.

PURPOSE: The new weekday-on/weekend-off schedule for oral UFT administration consists of its administration for 5 consecutive days followed by 2 days off the drug. The intratumor 5-FU (5-fluorouracil) concentration has been reported to be correlated to the tumor response in patients treated with intravenous 5-FU. The aim of this study was to investigate the pharmacokinetics during the 2 days off the drug in cancer patients treated with the weekday-on/weekend-off schedule for oral UFT. METHODS: The subjects were 24 colorectal cancer patients. They were divided into three groups, and were all given UFT, 600 mg/day, for 5 days before surgery. Surgery was performed 2, 24, or 48 h after the final dose of UFT. The 5-FU concentrations in the serum, tumor, and in the normal mucosa were measured. RESULTS: The serum 5-FU concentrations after the final dose of UFT were: 23 +/- 12 ng/ml (mean +/- SD) at 2 h, 7 +/- 3 ng/ml at 24 h, and 6 +/- 3 ng/ml at 48 h. The intratumor 5-FU concentrations were: 113 +/- 45 ng/g at 2 h, 54 +/- 20 ng/ml at 24 h, and 54 +/- 35 ng/ml at 48 h, and the concentrations in the normal mucosa were: 36 +/- 15 ng/g (mean +/- SD) at 2 h, 17 +/- 6 ng/ml at 24 h, and 18 +/- 6 ng/ml at 48 h after the final dose. While the serum 5-FU concentration decreased to very low levels by 24 h after the final dose of UFT, the intratumor 5-FU concentrations were maintained at more than 50 ng/g at least until 48 h after the final dose. The 5-FU concentrations in the normal mucosa were maintained at about one third of the intratumor concentrations at all time points. CONCLUSION: Although the weekday-on/weekend-off schedule for UFT administration included intermittent 2-day drug-off periods, this pharmacokinetic study revealed that the 5-FU concentrations in the tumor were maintained at much higher levels than in the serum throughout these periods.