Biomedical subjects

S Hishinuma

Publications and source records attributed to S Hishinuma.

At least 19 recordsLinked to original sources

PubMed2000

Isolation and characterization of the murine cardiotrophin-1 gene: expression and norepinephrine-induced transcriptional activation.

Cardiotrophin-1 (CT-1) is a novel cytokine capable of inducing hypertrophy in cardiac myocytes and belongs to the interleukin-6 family that exert their biological effects through gp130. To clarify the involvement and pathophysiological role of CT-1 in myocardial diseases, it is important to characterize the regulation of CT-1 gene expression. In this study, we isolated and characterized the mouse CT-1 gene and studied the expression of CT-1 mRNA under norepinephrine (NE) stimulation. The mouse CT-1 gene constitutes 5.4 kilobases (kb) in length and consists of three exons and two introns. When nucleotide sequences of the coding regions of exons were compared with those of human, exon 1, 2 and 3 share 96%, 84% and 81% homology, respectively. The 2.2 kb of 5; flanking lesion of the mouse CT-1 gene contains a variety of transcription factor binding motif (e.g. CREB, MyoD, NF-IL6, Nkx2.5, GATA). Fluorescent in situ hybridization (FISH) analysis demonstrated that the mouse CT-1 gene was located on chromosome 7F3. The expression of CT-1 mRNA in cardiac myocytes was markedly augmented by NE stimulation, both in vivo and in vitro. Promoter analysis using deletion constructs of the CT-1 gene indicated that the NE responsive element located between -2174/-1540 and this region contained the cAMP responsive element (CRE). Electrophoretic gel mobility shift assays showed enhanced binding activity to the CRE motif in the nuclear extracts from NE-stimulated cardiac myocytes. These studies indicate that CT-1 is abundantly expressed in the heart and that the CRE is a possible cis -acting element of the CT-1 gene under NE-stimulation. These data suggest that the CT-1 gene expression is regulated, at least partially, by transcriptional machinery.

Adrenergic alpha-Agonists↗

PubMed2000

Expressional patterns of cytokines in a murine model of acute myocarditis: early expression of cardiotrophin-1.

To determine the role of cytokines in acute myocarditis, we examined expressional patterns of cardiotrophin-1 (CT-1), TNF-alpha, and IL-1alpha in a murine model of acute myocarditis. Ten-day-old Institute of Cancer Research mice were injected with Coxsackievirus B3 and killed on Days 1, 2, 3, 4, 5, 7, 10, 14, and 28 of injection. TNF-alpha and IL-1alpha expressions were investigated on histological sections from each heart, and mRNA expression of TNF-alpha, IL-1alpha, and CT-1 in the heart was examined by reverse transcription-polymerase chain reaction and RNase protection assay. To determine myocardial regeneration, cardiomyocytic DNA synthesis was investigated using bromodeoxyuridine on Days 3, 5, 7, and 10, and the labeling index was calculated in each heart. Age-matched uninfected mice were used as controls. TNFalpha and IL-1alpha expression was first detected in the cardiomyocytes on Day 3 and reached the maximum level on Day 7, when inflammatory changes were most prominent. Although an increased expression of TNFalpha and IL-1alpha mRNA was also detected on Day 3, CT-1 mRNA expression was distinctly augmented on Day 2. The labeling indices in the hearts with myocarditis were significantly higher than in those of the controls in all of the time points examined. CT-1 expression preceded TNF-alpha and IL-1alpha expressions and active DNA synthesis in a murine model of acute myocarditis. All CVB3-infected mice with anti-glycoprotein-130 antibody treatment died within 6 days. CT-1 may exert a protective role by modulating cytokine production and by inducing cardiomyocytic proliferation in CVB3-infected murine hearts.

Acute Disease↗

PubMed2000

Author's reply

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Journal Article↗

PubMed2000

Ca(2+)/calmodulin-mediated regulation of the desensitizing process in G(q) protein-coupled histamine H(1) receptor-mediated Ca(2+) responses in human U373 MG astrocytoma cells.

We investigated Ca(2+)/calmodulin (CaM)-mediated regulation of the desensitizing process of the histamine H(1) receptor-mediated increase in intracellular Ca(2+) concentration in human U373 MG astrocytoma cells. The desensitizing process was evaluated by measuring the histamine-induced Ca(2+) responses in cells pretreated with histamine for 15 s-30 min under various conditions. Under normal physiological conditions, desensitization developed with three successive phases : a fast desensitization within 15 s, a transient resensitization at 45 s, and a prompt and sustained redesensitization from 1 to 30 min. Similar processes of desensitization/resensitization occurred even under hypertonic conditions, where histamine-mediated internalization of the histamine H(1) receptor is inhibited. The transient resensitization phase was selectively prevented by deprivation of extracellular Ca(2+) and, even more strikingly, by the presence of W-7 (a CaM antagonist). FK506 and cyclosporin A, Ca(2+)/CaM-dependent protein phosphatase (PP2B) inhibitors, mimicked such effects. In the presence of KN-62, a Ca(2+)/CaM-dependent protein kinase II (CaM kinase II) inhibitor, the early development of desensitization disappeared, allowing a slow and simple development of desensitization. The early processes of desensitization and resensitization were unaffected by W-5, okadaic acid, and KN-04 (less potent inhibitors against CaM, PP2B, and CaM kinase II, respectively) or by GF109203X and chelerythrine (protein kinase C inhibitors). The high-affinity site for histamine was converted to a lower-affinity site by histamine treatment, which also showed a transient restoration phase at 45 s in a manner sensitive to KN-62 and FK506. These results provide the first evidence that Ca(2+)/CaM plays a crucial role in determining the early phase of the desensitizing process via activation of CaM kinase II and PP2B, by regulating agonist affinity for histamine H(1) receptors.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗

PubMed2000

[Difficulty in using RP, PL, and EW factors in the Japanese classification of pancreatic carcinoma].

The classification of pancreatic carcinoma by the Japan Pancreas Society reflects the prognosis of each stage better than does the TMN classification. On the other hand, there are too many factors to examine in the Japanese system, some of which are difficult to use and have low accuracy in pre- and/or intraoperative diagnosis (RP and PL), and their analysis requires various specimen handling procedures (EW). We propose that: 1) a simple, easy decision flow chart be established for ew and 2) EW/ew be designated as (-) or (+) and for EW/ew (+) cases other factors (ly, v, pl, and direct tumor invasion) be added (for example, ew (+)-pl).

Humans↗

PubMed1999

Hypoxic stress induces cardiotrophin-1 expression in cardiac myocytes.

Cardiotrophin-1 (CT-1), a novel cytokine that belongs to the interleukin-6 cytokine family, activates gp130 dependent signaling pathway to transduce hypertrophic and cytoprotective signals in cardiac myocytes. To investigate the pathophysiological significance of CT-1 in myocardial disease, the expression of CT-1 was examined after hypoxic stimulation in cardiac myocytes. Highly expressed CT-1 mRNA was observed in embryonic and adult hearts by RNase protection assay. Cardiac myocytes subjected to hypoxic stimulation augmented CT-1 mRNA expression. Although CT-1 mRNA was expressed to a higher extent in non-myocardial cells, the expression was not affected with the stimulation. Conditioned medium from cultured cardiac myocytes presented the ability to tyrosine phosphorylate STAT3 through gp130 and that was further augmented with hypoxic conditioned medium. These results demonstrated for the first time that CT-1 expression is augmented after hypoxic stimulation and hypoxic conditioned medium presented enhanced ability to activate STAT3 in cardiac myocytes. CT-1 might play an important role in the pathogenesis of ischemic heart disease.

Animals↗

PubMed1999

Evaluation of pylorus-preserving pancreatoduodenectomy with the Imanaga reconstruction by hepatobiliary and gastrointestinal dual scintigraphy.

BACKGROUND: Following pylorus-preserving pancreatoduodenectomy (PPPD), most surgeons use gastrointestinal reconstruction with an end-to-side duodenojejunostomy placed distally to the pancreatojejunostomy and choledochojejunostomy. In contrast, the authors have consistently used PPPD with the Imanaga reconstruction (PPPD-Imanaga) which consists of end-to-end duodeno- jejunostomy, end-to-side pancreatojejunostomy and choledochojejunostomy, performed in that order. In this study, the movement of bile and food after PPPD-Imanaga was evaluated to document the functional advantages of this method. METHODS: Twenty-four patients who had undergone PPPD-Imanaga were subjected to hepatobiliary and gastrointestinal dual scintigraphy. The interval between operation and scintigraphy ranged from 28 days to 67 months. Six of the 24 patients underwent repeated dual scintigraphy for the observation of temporal changes in gastrointestinal function. RESULTS: The incidence of biliogastric reflux and bile stasis in the jejunal loop was markedly decreased at times later than 2 months after operation. Delay of gastric emptying and bile evacuation, sometimes accompanied by stasis in the jejunal loop, affected the mixing status of bile and food at 1 h after the beginning of imaging. A majority of the patients, however, had a satisfactory mixing status at 2 h. CONCLUSION: The Imanaga reconstruction appears to be a recommendable procedure following PPPD, in light of the bile and food movement achieved in the gastrointestinal tract.

Adult↗

PubMed1998

Results of surgery and adjuvant radiotherapy for pancreatic cancer.

We retrospectively reviewed the cases of 34 patients with pancreatic cancer who underwent resection between January 1988 and December 1996. Adjuvant radiotherapy was performed in 24 patients, with 13 receiving both intra- and postoperative radiotherapy, 2 receiving postoperative radiotherapy (PORT) alone, and 9 receiving intraoperative radiotherapy (IORT) alone. The 1- and 3-year survival rates for all 34 patients were 59% and 19%, respectively, with a median survival of 13 months. At the time of the analysis, three patients were still alive. Recurrence patterns were assessed in 25 patients who had had no distant metastases at the time of surgery, had survived more than 3 months after surgery, and had undergone close surveillance for recurrence. Based on computed tomography (CT) and autopsy findings, a total of 15 (60%) of these 25 patients had local recurrence, 13 (52%) had liver metastases, and 8 (32%) had both. Eight (62%) of the 13 patients who received IORT and/or PORT developed local recurrence, and we failed to detect any survival advantage of IORT and/or PORT over surgery alone. However, autopsies revealed a suppressive effect of radiation on cancer growth, and local recurrence was not considered to be the direct cause of death in any of the patients, nor did any of the patients develop gastrointestinal obstruction due to local recurrence. The incidence of liver metastasis in the patients with and without tumor invasion of the portal system was 80% (8/10) and 33% (5/15), respectively. The patients who did not develop liver metastasis had significantly longer survivals than who did. Further improvements of survival await effective prophylactic treatment for liver metastases.

Adult↗

PubMed1998

Complications after pylorus-preserving pancreatoduodenectomy with gastrointestinal reconstruction by the Imanaga method.

BACKGROUND: Pylorus-preserving pancreatoduodenectomies (PPPDs) have been performed for disorders of the pancreatic head and periampullary region. The most commonly used reconstructive technique anastomoses the duodenum end-to-side to the jejunum, with pancreatic and biliary anastomoses placed proximally to the end-to-side duodenojejunostomy. In contrast, we have favored PPPD with gastrointestinal reconstruction by the Imanaga method (PPPD-Imanaga), which consists of end-to-end duodenojejunostomy, end-to-side pancreatojejunostomy, and choledochojejunostomy, performed in that order, because the PPPD-Imanaga provides a physiologic mixture of food, pancreatic juice, and bile in the upper portion of the jejunum. STUDY DESIGN: To identify their postoperative complications, we retrospectively reviewed the cases of 55 patients who underwent a PPPD-Imanaga between December 1986 and December 1996. In all cases, the right gastric artery was divided and the pancreatic duct was sewn directly to a small opening in the jejunal mucosa. Twenty patients with malignancy received adjuvant radiotherapy. RESULTS: Five patients died without being discharged, including one who died of cancer progression, for a postoperative mortality rate of 9%. These deaths were limited to patients who had received adjuvant radiotherapy, with only two deaths being procedure related. Delayed gastric emptying, pancreatic leak, and marginal ulcer were observed in 25 (45%), 3 (5%), and 3 (5%) patients, respectively. The delay in gastric emptying was transient and resolved spontaneously, with no patients undergoing reoperation. Only one patient required a reoperation, for the control of intraabdominal bleeding. CONCLUSIONS: A PPPD-Imanaga can be performed with acceptable morbidity and mortality risks. We conclude that the Imanaga method is a favorable complement to PPPD.

Adult↗

PubMed1998

Ca2+/calmodulin-mediated regulation of agonist-induced sequestration of Gq protein-coupled histamine H1 receptors in human U373 MG astrocytoma cells.

We investigated the regulation by intracellular Ca2+ of agonist-induced sequestration of Gq protein-coupled histamine H1 receptors in human U373 MG astrocytoma cells. Histamine-induced sequestration of H1 receptors from the cell surface membrane was detected as the loss of [3H]mepyramine binding sites on intact cells accessible to the hydrophilic H1-receptor antagonist pirdonium. The changes in the pirdonium-sensitive binding of [3H]mepyramine were mirrored by changes in the subcellular distribution of H1 receptors detected by sucrose density gradient centrifugation. The histamine-induced sequestration of H1 receptors did not occur in hypertonic medium, in which clathrin-mediated endocytosis is known to be inhibited, but was significantly accelerated in the absence of extracellular Ca2+ or in the presence of the calmodulin antagonists W-7 and calmidazolium. Inhibitors of protein kinase C (H-7 and GF109203X), Ca2+/calmodulin-dependent protein kinase II (KN-62), or protein phosphatase 2B (FK506) did not alter the time course of H1-receptor sequestration. These results provide the first evidence that agonist-induced, clathrin-mediated sequestration of Gq protein-coupled receptors is transiently inhibited by Ca2+/calmodulin, with the result that receptors remain on the cell surface membrane during the early stage of agonist stimulation.

Astrocytoma↗

PubMed1998

Preoperative radiotherapy for cancer of the extrahepatic bile duct.

From January 1988 through June 1996, 12 patients who had extrahepatic bile-duct cancer received preoperative radiotherapy at doses of 40.6 Gy to 58.4 Gy. At restaging, 1 patient was found to have liver metastases and the remaining 11 patients were taken to surgery. Nine patients underwent resection, and 8 of the 9 received intraoperative radiotherapy. Complications occurred in 4 patients, 3 of whom died postoperatively. The 2 patients who died of intraabdominal complications received both preoperative radiation doses of more than 55 Gy and intraoperative radiotherapy doses of 14 Gy or more. Histologic evidence of irradiation effects was present in all specimens. Irradiation effects on perineural invasion were observed in varying degrees. Two of the four patients who had marked irradiation effects on perineural invasion developed local recurrence, which was found at autopsy to have infiltrated the hepatic hilum without obstructing the hepatic ducts. One patient who had minimal irradiation effects on perineural invasion developed local recurrence with obstructing the hepatic ducts. Of the 2 patients who had positive margins, the patient with marked irradiation effects on perineural invasion survived 18 months, but the patient with slight irradiation effects on perineural invasion survived only 5 months. The high complication rate requires modification of this strategy. The propriety of combining preoperative radiotherapy with intraoperative radiotherapy as well as the radiation dose should be reinvestigated.

Aged↗

PubMed1997

Contrasting effects of carbachol, McN-A-343 and AHR-602 on Ca(2+)-mobilization and Ca(2+)-influx pathways in taenia caeci.

1. We compared the binding profiles and contractile mechanisms of putative muscarinic M1 agonists McN-A-343 and AHR-602 with those of carbachol in smooth muscle of guinea-pig taenia caeci. 2. McN-A-343 and AHR-602, as well as carbachol, completely displaced the atropine-sensitive binding of [3H]-quinuclidinyl benzilate to muscarinic receptors present in the membrane preparation. The potency order for the affinity of these agents for muscarinic receptors was carbachol > McN-A-343 >> AHR-602. 3. In the presence of 2.2 mM extracellular Ca2+, McN-A-343 and AHR-602 induced contraction corresponding to 79 and 85%, respectively, of the maximal contraction to 0.1 mM carbachol. Contractions induced by these agents were mediated via activation of the muscarinic receptor subtype that had a high affinity for 4-DAMP (M3 selective) but a low affinity for pirenzepine (M1 selective) and AF-DX 116 (M2 selective). These contractions were inhibited by an L-type Ca2+ channel blocker, verapamil. 4. In Ca(2+)-free solution containing 2 mM EGTA, carbachol elicited a transient contraction whereas no contraction was observed in response to McN-A-343 and AHR-602. Application of McN-A-343 or AHR-602 inhibited the carbachol-induced contraction in Ca(2+)-free solution, and this inhibition was surmounted by a higher concentration of carbachol. 5. The EC50 value for carbachol-induced contraction in the presence of extracellular Ca2+ was approximately 175 times lower than that in the absence of Ca2+. After treatment with propylbenzilylcholine mustard, carbachol induced contraction only in the presence of extracellular Ca2+. 6. The results suggest that in the taenia caeci there is a greater receptor reserve for muscarinic M3 receptor-mediated Ca2+ influx than for M3 mediated Ca2+ release. The compounds McN-A-343 and AHR-602 are agonists of the Ca2+ influx pathway, but do not appear to stimulate the Ca2+ release pathway.

(4-(m-Chlorophenylcarbamoyloxy)-2-butynyl)trimethy↗

PubMed1997

[Indication and results of pancreatectomy with combined resection of vessels for adenocarcinoma of the pancreas].

Of 192 patients who received pancreatectomy for invasive adenocarcinoma of the pancreas, 107 (55. 7%) underwent combined resection of vessels at Keio University Hospital and Tochigi Cancer Center, from July 1974 until March 1996. Vascular resections included the portal and/or mesenteric vein in 103, the common hepatic artery in 14, the superior artery in 2 and the celiac axis in 5 cases. The morbidity and mortality rate are 20.2%, 1.2% in the standard resected group and 23.1%, 5.6% in the vessel resected group, respectively. Comparison of the survival rate of curability A and B patients between two groups shows no significant difference. Six patients who underwent resection of the portal and/or mesenteric vein survived more than 5 years. The longest survivor is living 13 years 6 months after surgery. Among the patients who underwent resection of the artery, two patients survived 44 and 22 months after distal pancreatectomy with resection of the celiac axis and the common hepatic artery preserving whole stomach.

Adenocarcinoma↗

PubMed1996

Morgagni hernia diagnosed by MRI.

We herein present a patient with Morgagni hernia which was diagnosed by magnetic resonance imaging (MRI). The patient had a progressively enlarging mass in the right cardiophrenic angle on chest roentgenogram. On computed tomography (CT) scans, the mass was revealed to have fat density and therefore was suspected to be either a lipoma or liposarcoma. MRI clearly demonstrated that the mass shadow was composed of omental fat herniating into the right thorax through the diaphragmatic hiatus. MRI is thus considered to be a useful noninvasive modality for the evaluation of lower anterior mediastinal masses demonstrating fat density on CT.

Adipose Tissue↗

PubMed1996

[Two cases of von Recklinghausen's disease with diffuse pulmonary changes].

Two patients with von Recklinghausen's disease had diffuse pulmonary diseases. The pulmonary diseases were interstitial fibrosis and emphysematous bullae. In case 2, examination of a specimen obtained by transbronchial lung biopsy revealed fibrotic interstitial thickening and adenomatous hyperplasia. Diffuse pulmonary abnormalities in von Recklinghausen's disease have been said to be fibrotic changes and emphysematous changes, as shown in roentgenograms in these two cases. The biopsy specimen obtained in case 2, however, revealed fibrotic changes only, which could not be distinguished from findings in cases of idiopathic interstitial pneumonia. In case 2, bronchoalveolar lavage fluid was also examined but it did not reveal any unique features of von Recklinghausen's disease. Since 1978, von Recklinghausen's disease has been diagnosed 10 times in our hospital, but diffuse pulmonary diseases was seen in only two of those 10 cases.

Adult↗

PubMed1995

Characteristics of the binding of [3H]-mepyramine to intact human U373 MG astrocytoma cells: evidence for histamine-induced H1-receptor internalisation.

1. The kinetics of the binding of 5 nM [3H]-mepyramine to sites on intact human U373 MG astrocytoma cells, sensitive to inhibition by 2 microM pirdonium, were temperature-dependent. At 37 degrees C the half-time for association was 0.9 +/- 0.4 min and at 4 degrees C 19 +/- 3 min. Dissociation of bound [3H]-mepyramine was fast at 37 degrees C, t0.5 1.5 +/- 0.3 min, but at 6 degrees C dissociation initiated by dilution or addition of unlabelled mepyramine was negligible over 120 min. The very slow dissociation at 6 degrees C made it possible to reduce the level of pirdonium-insensitive binding from 56 +/- 5% to 39 +/- 5% by washing the cells in ice-cold medium before filtration. 2. The binding of [3H]-mepyramine sensitive to 2 microM temelastine, measured after 10 min equilibration at 37 degrees C, failed to saturate and was resolved into an hyperbola and an apparently linear component, whereas the fit to the binding of [3H]-mepyramine sensitive to 2 microM pirdonium was not significantly improved over that to an hyperbola. The mean Kd for the binding of [3H]-mepyramine to the saturable component, 2.5 +/- 0.4 nM, was in close agreement with the value of 3.5 nM for mepyramine derived from inhibition of histamine H1-receptor-mediated inositol phosphate formation in U373 MG cells. 3. Curves for the inhibition of the binding of 5 nM [3H]-mepyramine to U373 MG cells by histamine H1-receptor antagonists were biphasic and were fitted to a two site-model. Affinities calculated from the best-fit IC50 values for the high-affinity site correlated well with those expected for binding to H1-receptors. 4. The percentages of the high-affinity site in curves of the inhibition of [3H]-mepyramine binding to intact U373 MG cells by two tertiary amine antagonists, norpirdonium and 4-methyldiphenhydramine, 68 +/- 3 and 63 +/- 4%, were significantly greater than the percentages of the high-affinity site in the inhibition curves of their quaternary derivatives, 50 +/- 1 and 45 +/- 3%, respectively. Similarly, the percentage of the high-affinity site for unlabelled mepyramine, 65 +/- 7%, was greater than for the non-cell penetrant H1-antagonist temelastine, 42 +/- 5%. 5. Incubation of U373 MG cells with 100 microM histamine at 37 degrees C, followed by washing twice in ice-cold medium and then incubation with 1-15 nM [3H]-mepyramine for 120 min at 4 degrees C, resulted in a decrease in the binding of [3H]-mepyramine sensitive to 2 microM pirdonium, compared to control cells not exposed to histamine. The binding of [3H]-mepyramine in the absence of pirdonium was not altered by histamine pretreatment, whereas the level of the pirdonium-insensitive binding was significantly increased, except after 1 min exposure to histamine. The decreases in the pirdonium-sensitive binding after 5, 10 and 60 min incubation with 100 microM histamine were 41 +/- 6, 56 +/- 6 and 67 +/- 8%, respectively, but the decrease after 1 min incubation with histamine, 16 +/- 8%, was not statistically significant. 6. The results are consistent with the binding of [3H]-mepyramine to intact U373 MG cells being to both plasma membrane and intracellular histamine H1-receptors. The high-affinity binding sensitive to the non-cell penetrant quaternary compounds and to temelastine is thus to plasma membrane H1-receptors. On exposure to 100 microM histamine receptors are translocated to the intracellular pool, since the change in the high-affinity binding of [3H]-mepyramine is primarily in the level of the pirdonium-insensitive binding, rather than in the total binding.

Astrocytoma↗

PubMed1994

[Desensitization of the m3-muscarinic acetylcholine-receptor in the smooth muscle and the intracellular signal transduction].

Desensitization of the m3-muscarinic acetylcholine-receptor in the smooth muscle of the digestive tract is discussed together with the changes in intracellular signal transduction. Isolated single cells that show an all-or-none contractile response to acetylcholine were desensitized by treatment with 0.1 mM acetylcholine for 10 min, resulting in an increase in the threshold concentration of acetylcholine for contraction, but without changing any of the binding characteristics. Permeabilized cells showed that the desensitization is via uncoupling between the receptor and G-protein. Secretory cells (rat basophil leukemia-2H3 cells) transfected with human m3-receptor showed desensitization when treated with 0.1 mM carbachol for 30 min. The coupling between the receptor and G-protein was not impaired, but some unknown Ca(2+)-independent mechanism may be involved. Smooth muscle tissue was tested for its time-course of desensitization, and a novel transient resensitization was found at 1 min of incubation with 0.1 mM carbachol. This resensitization, and the desensitization prior to it, were accompanied with changes in binding affinity. However, the affinity was not changed, in parallel with desensitization afterwards, but the positive feedback loop of Ca(2+)-influx caused by alkalization via receptor-stimulation was suppressed. After a 30-min treatment, a Ca(2+)-independent mechanism caused the uncoupling and affinity decrease. Treatment for 3 hr increased the number of binding sites without recovery of the response. The desensitizing process is very diverse to achieve selectivity, but its purpose is in unity.

Animals↗

PubMed1993

A pharmacodynamic and pharmacokinetic study of fluoropyrimidines in a nude mouse system and in postoperative patients with gastric cancer.

To evaluate the effect of the oral fluoropyrimidines, tegafur and uracil (UFT) and 5-fluorouracil (5-FU), a pharmacodynamic analysis was conducted using a nude mouse system and patients. In the nude mouse system, UFT and 5-FU showed similar marginal effects against the human tumor xenograft Co-4, and the concentration of 5-FU in serum 1 h after the last administration being 0.04 micrograms/ml, which was assumed to be the minimum effective concentration. (MEC). Postoperative patients were subdivided into three groups, being: those who underwent subtotal gastrectomy and received UFT; those who underwent subtotal gastrectomy and received 5-FU; and those who underwent total gastrectomy and received UFT. In the UFT groups, the concentration of 5-FU in the portal and peripheral blood showed similar elimination in terms of the peak concentration (Cmax) and the area under the curve (AUC). In the 5-FU groups, the AUC and Cmax were significantly higher in portal blood than peripheral blood. The concentrations in the portal blood of the 5-FU group and in the portal and peripheral blood of the UFT group were significantly higher than the MEC (0.04 micrograms/ml). From these pharmacodynamic data, it was concluded that postoperative chemotherapy with oral fluoropyrimidines can achieve the MEC in portal and peripheral blood.

Adenocarcinoma↗