[A case of huge liver metastasis from jejunal leiomyosarcoma completely controlled by intra-arterial and intra-portal vein infusion chemotherapy following hepatectomy]

A 39-year-old woman was found to have intrapelvic tumor and multiple liver metastases by abdominal computed tomography. Although laparotomy was done under the diagnosis of ovarian cancer with liver metastases, the histological diagnosis of the tumor during the operation was jejunal leiomyosarcoma. Only the primary lesion was removed at the same time. Three weeks later, right lobectomy of the liver and catheterization of the hepatic artery and the portal vein were carried out for liver metastases. Following the procedure, intra-arterial and intra-portal vein infusion chemotherapy of epirubicin was performed every 2 weeks. The patient has been well for 1 year and 11 months with complete remission.

["Wrapping therapy" for hepatocellular carcinomas with collateral feeders]

A new treatment method to intercept collaterals with silicone rubber sheeting, called "wrapping therapy", was used for 18 patients with advanced hepatocellular carcinomas having collateral feeders from other organs surrounding the liver. Chemoembolization in 17 of the 18 patients in whom it had been conducted more than once, had proven ineffective. Obvious collateral feeders (parasitic branches) to the tumors were recognized on hepatic angiograms in two-thirds of the patients. This procedure was followed by regional chemotherapy and/or chemoembolization. The 3- and 4-year survival rates of the patients after "wrapping therapy" were 54% and 54%, respectively. This therapy is worth using for hepatocellular carcinomas uncontrolled by arterial therapy because of development of collateral feeders.

The detection of breast carcinoma micrometastases in axillary lymph nodes by means of reverse transcriptase-polymerase chain reaction

BACKGROUND

The development of a sensitive method for the detection of breast carcinoma micrometastases in axillary lymph nodes is reported.

METHODS

The method was based on amplification of MUC1 mRNA, which encodes a core protein of polymorphic epithelial mucin, by a reverse transcriptase-polymerase chain reaction (RT-PCR). Total RNA, which was extracted from a breast carcinoma cell line (MCF-7), primary breast carcinomas, and axillary lymph nodes, was subjected to analysis of MUC1 mRNA expression by the RT-PCR method.

RESULTS

MUC1 mRNA expression was detected by RT-PCR in MCF-7 cells and in all 15 primary breast carcinomas but not in control lymph nodes taken from patients with benign diseases. A serial dilution study revealed that MUC1 RT-PCR was a very sensitive method, detecting one MCF-7 cell per 1,000,000 lymph node cells. The detection sensitivity of MUC1 RT-PCR method was compared with that of immunohistochemical staining of an epithelial marker (polymorphic epithelial mucin). Fifty axillary lymph nodes were obtained from 15 patients with primary breast carcinomas, and metastasis in each lymph node was investigated by both methods. The immunohistochemical method demonstrated metastasis in nine lymph nodes, and MUC1 mRNA was detected in all of them. Of the 41 lymph nodes that were diagnosed to be devoid of metastasis by immunohistochemistry, MUC1 mRNA was expressed by 6 but not by the other 35, indicating the presence of micrometastases in these 6 lymph nodes that could be detected only by the MUC1 RT-PCR method.

CONCLUSIONS

The MUC1 RT-PCR method is more sensitive than immunohistochemistry for the detection of micrometastases in axillary lymph nodes. This new method would be of practical value in selecting the patients at high risk for relapse from those who are histologically lymph node negative.

[Promotion of hematogenous metastasis in relation to endothelial cell injury by treatment with anticancer drugs]

It has been reported that anticancer drugs at high concentration increase experimental hematogenous metastasis owing to endothelial injury. In this study, we evaluate the effects of anticancer drugs at clinical doses on endothelial cells in the process of metastasis. To do so, we have developed in vitro assay methods which can assess endothelial cell retraction and barrier function against invasion by tumor cells. 5-FU at clinical doses caused neither retraction nor decreasing barrier function, however, ADR and MMC caused retraction of endothelial cells and increased invasion by tumor cells. These effects reached maximum 12 hours after treatment with ADR or MMC, and the number of liver metastases was also significantly increased in in vivo study when tumor cells were injected via portal vein at 12 hours after administration of ADR. It was suggested that some kinds of anticancer drugs at the clinical dose may increase hematogenous metastasis in treatments.

[A case of hepatocellular carcinoma implantation to chest wall by percutaneous ethanol injection therapy]

A 62-year-old male patient with hepatocellular carcinoma (HCC) received percutaneous ethanol injection therapy (PEIT) four times following fine needle biopsy (FNB). Six months later, he underwent partial hepatic resection because of the insufficient anti-cancer effect of PEIT. One year and five months after PEIT, a subcutaneous tumor, which appeared to be a needle tract seeding by PEIT, was recognized in the 9th intercostal space of the right chest wall. A curative resection of the partial chest wall, including IXth and Xth ribs, was carried out with reconstruction using dexon mesh five months later. The tumor was 3.5 cm in size, and the histology was moderately-differentiated HCC. PEIT is a useful treatment for small HCCs. When PEIT is carried out, due care should be taken for neoplastic needle-tract seedings as one of the possible complications.

Changes in content of P450 isozymes in hepatic and renal microsomes of the male rat treated with cis-diamminedichloroplatinum

1. The changes in the activity of drug-metabolizing enzymes and in the content of P450 isozymes in renal and hepatic microsomes after treatment of the male Sprague-Dawley rat with cis-diamminedichloroplatinum (Cisplatin, CDDP) were examined. 2. NADPH-P450 reductase activity in renal microsomes was significantly increased by treatment with CDDP, but lauric acid omega- and (omega-1)-hydroxylation activities of renal microsomes were not increased. 3. The level of P4502C23 was increased significantly and levels of P4504A2 and 4A8 tended to increase in renal microsomes. 4. In hepatic microsomes, lauric acid omega-hydroxylation activity was increased, but (omega-1)-hydroxylation activity was not. Levels of P4502C11 and 3A2, which are male-specific forms, were decreased, whereas levels of P4502A1, 2C7 and 2E1 were increased in hepatic microsomes. The levels of P4504A2 and 4A3 were increased by CDDP and the level of P4504A1 was not changed. Changes in the protein levels of P450 by CDDP were consistent with those in the mRNA levels reported previously (LeBlanc et al. 1992). 5. Male-specific forms in rat liver such as P4502C11 were decreased by CDDP, but those in the kidney such as P4504A2 was not. Therefore, CDDP has different influences on the regulation of hepatic and renal P450s.

[Adjuvant chemo-endocrine chemotherapy with gastrin antagonist after resection of liver metastasis in colorectal cancer]

This study was designed to determine whether or not chemo-endocrine therapy after the resection of liver metastasis from colorectal cancer would prevent re-recurrence in the liver. Postoperatively, seven patients received proglumide gastrin antagonist (1,200 mg/day) +5'-DFUR (800 mg/day) orally for 2 years. MMC 6-10 mg and ADR 20 mg were infused every two weeks alternately for 1 year via catheter in the common hepatic artery. After median follow-up of 39 months, re-recurrence rate in the remnant liver after hepatic resection was 14% (1/7) for patients with chemo-endocrine therapy and 52% (24/46) for the controls. These results suggest the possibility that chemo-endocrine therapy is effective to prevent re-recurrence of liver metastasis in patients with colorectal cancer.

Necrosis of hepatocellular carcinoma caused by spontaneously arising arterial thrombus

This paper describes a 65-year-old Japanese man with hepatocellular carcinoma (HCC) in whom the alpha-fetoprotein level decreased remarkably without any treatment. Plain computed tomography disclosed a low-density area in the left lateral segment. Liver scintigraphy revealed a filling defect with 99mTc-Sn colloid and increased uptake of 67Ga-citrate. The latter was smaller in area than the former. This indicates that non-necrotic HCC was still present at this time. There was no hypervascular lesion in the hepatic angiogram obtained 22 days after liver scintigraphy. The tumor was resected by partial hepatectomy 24 days after hepatic angiography. The histological section showed almost complete necrotization of the tumor, and the necrotic change consisted of old and recent necrosis. An arterial thrombus was formed in non-tumor liver tissue. It was presumed that coagulative necrosis was produced by interruption of the blood supply due to the spontaneous formation of an arterial thrombus.

Discrimination between multicentric and multifocal carcinomas of the breast through clonal analysis

BACKGROUND

An unanswered, important question concerning multiple breast carcinomas is whether they arise independently in the breast (multicentric) or are metastatic deposits from a single, primary carcinoma (multifocal). This issue was studied by clonal analysis of each focus of multiple breast carcinomas.

METHODS

First, the clonality of 30 breast carcinomas was analyzed by the method based on restriction fragment length polymorphism of the X-chromosome-linked phosphoglycerokinase (PGK) gene and on random inactivation of the gene. Second, the clonality of each focus of three multiple breast carcinomas was analyzed by the same method.

RESULTS

Clonal analysis of the 30 breast carcinomas revealed that every carcinoma was monoclonal in origin, and one of two alleles of the PGK gene was inactivated at random in these carcinomas. Three patients with multiple breast carcinomas had three, three, and four histologically separate foci of carcinoma in the breast, respectively. Clonal analysis showed that each focus was monoclonal in origin and, in addition, the same allele of the PGK gene was inactivated consistently at each focus in every patient.

CONCLUSIONS

The thesis that multiple carcinoma foci arise independently is unlikely to be true, because the probability that every independent focus happens to inactivate the same allele of PGK gene in every patient is very low. It seems more likely that a single primary carcinoma spreads throughout the breast to culminate in multiple secondary carcinoma foci. Therefore, it is concluded that multiple breast carcinomas are multifocal and not multicentric in origin.

Clonal analysis of solitary intraductal papilloma of the breast by means of polymerase chain reaction

Clonality of solitary intraductal papillomas of the breast was analyzed using a method based on restriction fragment length polymorphism of the X-chromosome-linked phosphoglycerokinase (PGK) gene and on random inactivation of the gene by methylation. The application of polymerase chain reaction to this method enabled clonal analysis of such a small intraductal lesion as papilloma. Clonal analysis of DNA samples obtained from the nine solitary intraductal papillomas and adjacent normal breast tissues showed that all of the papillomas were monoclonal and all the normal breast tissues were polyclonal in origin. When DNA samples were obtained from four widely separated sites in the papillomas, clonal analysis showed that all were monoclonal and, in addition, the same allele of PGK gene was inactivated in each case. These results demonstrate that solitary intraductal papilloma arises as a single monoclonal tumor and extends along the ducts rather than occurring as multicentric monoclonal tumors and merging together subsequently. Immunohistochemical staining of smooth muscle alpha-actin, a marker protein of myoepithelial cells, revealed that solitary intraductal papilloma was composed of approximately equal mixtures of luminal epithelial and myoepithelial cells. Since solitary intraductal papillomas were shown to be monoclonal in origin, it was suggested that this disease originates from a common precursor that could differentiate into both luminal epithelial and myoepithelial cells.

Analysis of factors affecting uptake of Tc-99m Sn-N-pyridoxyl-5-methyltryptophan by hepatocellular carcinoma

We performed Tc-99m PMT imaging in 176 patients with HCC and evaluated factors affecting 99mTc-PMT uptake by HCC with a logistic model. The probability of HCC showing increase in uptake of the radioisotope was 104.6 times higher in patients with the Ed I type than in those with the Ed III type and 12.1 times higher in patients with a tumor diameter of 5.0-7.9 cm than in those with a tumor diameter of 2.0-5.0 cm. Among the other variables, the serum AFP level and sex were suggested to have effects similar to those of the tumor size on Tc-99m PMT uptake by HCC. The grade of morphological differentiation of the tumor was therefore most markedly related to Tc-99m PMT uptake.

Surgical treatment of adrenal metastasis following pulmonary resection for lung cancer: comparison of adrenalectomy with palliative therapy

Although adrenal metastases from lung cancer are frequently detected during the late clinical stage or at autopsy, they are rarely surgically treated following pulmonary resection for lung cancer. We detected adrenal lesions as initial clinical recurrence in 9 (1%) of 904 patients who underwent pulmonary resection for lung cancer at our institute between 1980 and 1992. Adrenalectomy was performed in five who had developed unilateral adrenal metastasis. One underwent simultaneous operation for primary and metastatic lesions, and 4 underwent adrenal surgery following pulmonary resection. The adrenal tumor was removed via laparotomy in three patients, and via posterolateral non laparotomic approach in two. Co-metastatic lesions which were detected incidentally at operation included intestinal metastasis in two patients and regional lymph node metastasis in two; these were simultaneously resected. Following adrenalectomy, all these patients were treated with adjuvant chemotherapy or radiotherapy. Two patients have remained free of relapse for 40 and 26 months, respectively, after adrenal surgery, while three died of other distant metastases more than 9 months after adrenalectomy. In contrast, the four patients who received chemotherapy or radiation therapy died less than 6 months after palliative therapy. Thus, we consider that surgical treatment for adrenal metastases following pulmonary resection for lung cancer is effective in selected cases. The indications for adrenalectomy are presented in comparison with those for palliative therapy, and several difficulties in the surgical management of adrenal metastases are discussed.

Clonal analysis of predominantly intraductal carcinoma and precancerous lesions of the breast by means of polymerase chain reaction

Clonality of predominantly intraductal carcinoma (PIC) and precancerous lesions of the breast was analyzed by a method based on restriction fragment length polymorphism of the X-chromosome-linked phosphoglycerokinase gene and on random inactivation of the gene by methylation. The application of polymerase chain reaction to this method enabled clonal analysis of small lesions. In order to eliminate the contamination by normal stromal cells, intraductal components were microdissected from the frozen sections of PIC under a dissection microscope. Clonal analysis of the intraductal components from seven PICs revealed that all were monoclonal in origin. In three PICs with intraductal spreading of carcinoma cells over nearly a whole breast gland, the intraductal components were collected from eight widely separated sites in each case. Clonal analysis of these samples showed that every sample was monoclonal and the same allele of the phosphoglycerokinase gene was consistently inactivated in each case. These results suggest that PIC arises as a single monoclonal carcinoma and spreads through the ducts over the gland rather than having multicentric origins. Clonality of precancerous lesions such as atypical ductal hyperplasia and intraductal papilloma arising in the terminal ducts was also studied. Intraductal components were microdissected from the paraffin sections of these lesions and subjected to clonal analysis. Both atypical ductal hyperplasia and intraductal papilloma were found to be monoclonal in origin, suggesting that certain genetic changes had already occurred in the precancerous lesions. A further study is needed to elucidate these genetic changes, which would greatly help our understanding of the mechanism of carcinogenesis.

Clonal analysis of parathyroid adenomas by means of the polymerase chain reaction

Clonality of parathyroid adenomas and normal parathyroid glands was analyzed by a method based on restriction fragment length polymorphism of the X-chromosome-linked phosphoglycerokinase (PGK) gene and on random inactivation of the gene by methylation. Through the introduction of the polymerase chain reaction to this method, clonal analysis could be performed on small DNA samples prepared from cryostat sections of these specimens. Every normal parathyroid gland was found to be polyclonal while every parathyroid adenoma was found to be monoclonal. When DNA samples obtained from four widely separated sites of an adenoma were independently analyzed, each sample was found to be monoclonal and, in addition, the same allele of PGK gene was inactivated. These results suggest that parathyroid adenoma, which has a single cell origin, is a true neoplasm and that its pathogenesis is probably different from that of parathyroid hyperplasia which is polyclonal in origin.

Differentiation of primary and secondary breast cancer with clonal analysis

BACKGROUND

It is often difficult to draw a firm conclusion as to whether the second breast cancer is primary or secondary (metastasis from the initial breast cancer) in a patient with metachronous bilateral breast cancer. In this study we have applied clonal analysis of breast cancer to distinguish whether the second breast cancer is primary or secondary.

METHODS

A 54-year-old woman underwent modified radical mastectomy of the right breast as a result of breast cancer. Five years later she had tumors in the right chest wall and left breast. Fine-needle aspiration cytologic examination revealed that both tumors were adenocarcinoma. To elucidate the origin of these tumors, clonal analysis was done on DNA samples prepared from cryostat sections of the initial right breast cancer and from fine-needle aspirates of the tumors in the right chest wall and left breast. The method for clonal analysis was based on restriction fragment length polymorphism of X chromosome-linked phosphoglycerokinase gene and on differential methylation of the gene caused by random inactivation of one of two X chromosomes.

RESULTS

Clonal analysis revealed that clonal origin of the right breast cancer was different from that of the left breast cancer and identical to that of the chest wall tumor. Therefore it was concluded that the left breast cancer was primary and the chest wall tumor was concluded that the left breast cancer was primary and the chest wall tumor was a recurrence of the initial breast cancer.

CONCLUSIONS

Clonal analysis appears to be a useful method in discriminating a primary from a secondary cancer.

Apoptosis of acinar cells in the pancreas of rats fed on a copper-depleted diet

Male Fischer 344 rats weighing 80-90 g were fed on a copper-depleted diet supplemented with 0.6% triethylenetetramine tetrahydrochloride (a copper chelator), and the death of pancreatic acinar cells of these rats was investigated morphologically and biochemically. The weight of the pancreas of these rats decreased from 3 weeks after feeding, and concomitantly the percentage of dead acinar cells increased to the maximum in about the 5th week and decreased subsequently. These dead acinar cells showed light microscopic and electron microscopic characteristics of apoptosis. Furthermore, the electrophoretic pattern of DNAs extracted from the pancreas having many dead acinar cells showed a ladder-like distribution, characteristic of apoptosis. The present results indicate that feeding of rats on a copper-depleted diet supplemented with a copper chelator results in apoptosis of acinar cells of the pancreas.

Trimethadione metabolism, a useful indicator for assessing hepatic drug-oxidizing capacity

The metabolism of trimethadione (TMO), a useful indicator of hepatic drug-oxidizing capacity in rats and humans, was studied using 14 different forms of rat cytochrome P450 (CYP1A1, 1A2, 2A1, 2A2, 2B1, 2B2, 2C6, 2C7, 2C11, 2C12, 2C13, 2E1, 3A2 and 4A2) and three forms of human cytochrome P450 (CYP1A2, 2C and 3A4). TMO N-demethylation was increased by treating rats with phenobarbital. CYP2C11 and 2B1 had high TMO N-demethylase activity, but 1A1 and 1A2 had low activity. Antibodies raised to CYP2C11 and 2B1/2 inhibited TMO N-demethylation in hepatic microsomes of untreated and phenobarbital-treated rats, respectively. In a reconstituted system, human CYP3A4 and 2C produced efficiently dimethadione (DMO), but CYP1A2 did not catalyse TMO N-demethylation. Antibodies raised to CYP3A2 and 2C11 inhibited TMO N-demethylation in human hepatic microsomes. These results indicated that the N-demethylation of TMO is catalysed mainly by CYP2C11 and 2B1 in rat hepatic microsomes, and that human CYP3A4 and an unspecified isoform of the 2C subfamilies contribute to TMO N-demethylation in human liver.

Gastric cancer in young adults: growth accelerating effect of pregnancy and delivery

The relationship between pregnancy and/or delivery (p&d) and the stage of gastric cancer was studied in 64 female and 57 male patients aged 34 or younger with gastric cancer. Gastric cancer diagnosed within 2 years after p&d (group A, 20 patients) was more progressive (unresectable in 20%) than those of the other young female patients with children (group B, 24 patients; 5%) or without children (group C, 20; 0%), or young male patients (group D, 57; 3%) (P < 0.05). The 5-year survival rate in group A (60.0%) was lower than in group B (83.3%) and group C (85.0%) (P < 0.05 between groups A and B). There were no differences in the duration from the onset of subjective symptoms to diagnosis in the four groups. Out of eight patients who were pregnant after gastrectomy for stomach cancer, one died from recurrence immediately after abortion. These results suggest that pregnancy and/or delivery in young females accelerates the growth of stomach cancer.

Regulation of renal cytochrome P450s by thyroid hormone in diabetic rats

Effects of thyroid hormone treatment on renal P450 expression in the diabetic rats were investigated. Diabetes produced by streptozotocin induced CYP4A2 and P450 K-2 (similar form with CYP2C23) but not P450 K-4 (similar form with CYP4A8) and induced lauric acid hydroxylation activity. The serum thyroid hormone level was decreased with diabetes. Treatment of diabetic rats with thyroid hormone (T3) as well as with insulin reversed the increase in the levels of CYP4A2 and P450 K-2. Thyroidectomy also induced CYP4A2 and P450 K-2 in the rat kidney. The increase was reversed by treatment of thyroidectomized rats with T3. These findings suggest that expression of CYP4A2 and P450 K-2 in rat kidney is suppressively regulated by thyroid hormone and the decrease in thyroid hormone level in the diabetic state affects the levels of CYP4A2 and P450 K-2.

Complete cDNA sequence and cDNA-directed expression of CYP4A11, a fatty acid omega-hydroxylase expressed in human kidney

A cDNA was isolated from a human kidney lambda gt10 library using the rat CYP4A3 cDNA as a probe. The cDNA-deduced amino acid sequence encoded a protein of 519 amino acids that was designated CYP4A11 (Nelson et al., 1993) and exhibited 76%, 72%, 80%, and 53% similarities to rat CYP4A1, rat CYP4A3, rabbit CYP4A6, and human CYP4B1, respectively. The deduced amino-terminal amino acid sequence of this cDNA agreed with the amino-terminal amino acid sequence of a major P450 protein purified from human renal microsomes. A second variant form of CYP4A11 cDNA, designated CYP4A11v, was isolated from the same library and had a deletion of a single adenine residue, thereby extending the reading frame and resulting in a protein of 591 amino acids. CYP4A11v is probably encoded by a rare allelic variant of CYP4A11, since no mutant alleles were uncovered in 15 normal individuals, as determined by a polymerase chain reaction (PCR) diagnostic test. Baculovirus-mediated cDNA expression of CYP4A11 yielded a P450 protein having a lambda max of 452 nm when reduced and complexed with carbon monoxide. The expressed enzyme efficiently catalyzed omega-hydroxylation of lauric acid. No detectable activity was uncovered toward arachidonic acid and prostaglandin E1. The cDNA-expressed variant, CYP4A11v, was found to be unstable and not to efficiently metabolize lauric acid, as assessed by both baculovirus and monkey kidney COS cell cDNA expression systems. These studies indicate that CYP4A11 is a major fatty acid-metabolizing P450 that is expressed in human kidney.

Increased CYP1A2 content and capacity to activate Glu-P-1 and Trp-P-2 in liver microsomes of scorbutic ODS rats

Osteogenic Disorder Shionogi (ODS) rats, which cannot synthesize ascorbic acid due to a deficiency of L-gulonolactone oxidase, become scorbutic when not supplied with dietary ascorbic acid. We used the deficient rats to study the effects of ascorbic acid on the amount of cytochrome P450 enzymes in liver microsomes. The total amount of hepatic cytochrome P450 in ODS rats deprived of ascorbic acid was lower by approximately 40%, whereas ODS rats fed with ascorbic acid and the wild strain had the same level of total hepatic cytochrome P450. Western blot analysis for various forms of cytochrome P450 in liver microsomes indicated that the amount of CYP1A2 was significantly higher in ascorbic acid deficient rats. On the other hand, amounts of CYP2B2 and 3A were lower, and those of CYP2E1 and CYP2C6/11 were unaffected. In accordance with the higher amount of CYP1A2, Northern blot analysis showed increased expression of CYP1A2 mRNA. The capacity of microsomes to produce mutagens from 2-amino-6-methyl-dipyrido[1,2-a:3',2'-d]imidazole acetate (Glu-P-1) and 3-amino-1-methyl-5H-pyrido[4,3-b]indole acetate (Trp-P-2) was higher in scorbutic ODS rats by the Ames test. These results indicate that the effects of ascorbic acid deficiency on the expression of cytochrome P450 in ODS rat livers are form-specific and that the increased CYP1A2 is associated with increased metabolic activation of promutagens in the scorbutic state.

Characterization of two P-450 isozymes placed in the rat CYP2D subfamily

Two P-450s with debrisoquine 4-hydroxylation activity, designated P-450 UT-7 and UT-7b, were purified and partially purified, respectively, from hepatic microsomes of untreated male rats. Both purified P-450s with an apparent molecular weight of 49,000, were associated with another protein with an apparent molecular weight of 29,000 which was designated 29 k-protein. The CO-reduced spectra of both P-450 UT-7 and UT-7b showed a peak at 448 nm. The NH2-terminal amino acid sequences of P-450 UT-7 and UT-7b were the same as the amino acid sequences of CYP2D1 and CYP2D2 deduced from the cDNA, respectively, except for the lack of a terminal methionine for P-450 UT-7b. In a reconstituted systems, P-450 UT-7 and UT-7b catalyzed lidocaine 3-hydroxylation and N-deethylation in the presence of the 29 k-protein. The Km and Vmax values for lidocaine 3-hydroxylation were 3.6 microM and 0.50 nmol/min/nmol of P-450 for P-450 UT-7, and 3.6 microM and 0.93 nmol/min/nmol of P-450 for P-450 UT-7b, respectively. Antibody against P-450 UT-7, which also cross-reacted with P-450 UT-7b, inhibited lidocaine 3-hydroxylation in liver microsomes from untreated male rats, but had little effect on lidocaine N-deethylation. These findings suggested that lidocaine 3-hydroxylation in hepatic microsomes from untreated male rats was catalyzed by P-450 UT-7 and/or UT-7b.P-450 UT-7 not containing 29 k-protein was obtained as the non-absorbed fraction from hydroxylapatite HPLC. The activities of debrisoquine 4-hydroxylation as well as lidocaine 3-hydroxylation and N-deethylation in a reconstituted system with P-450 UT-7 without 29 k-protein were one-fifth of those of P-450 UT-7 containing 29 k-protein at the same substrate concentration. These findings suggested that the 29 k-protein was essential to express the maximal metabolic activities. However, the lidocaine metabolic activity in a reconstituted system with P-450 UT-7 containing 29 k-protein and in hepatic microsomes were not inhibited by 29 k-protein antibody.

Identification of CYP2C23 expressed in rat kidney as an arachidonic acid epoxygenase

A cDNA was isolated from a rat kidney cDNA library using mixed probes of CYP (cytochrome P450) 2C6, 2C7, 2C8, 2C9 and 2C18 cDNAs. The 3'-terminal and 5'-terminal regions of the cDNA were sequenced and were identical with those of cytochrome P450 2C23 (CYP2C23) except for a one-base deletion and a one-base addition in coding region. These changes caused a frame shift and changed the deduced amino acid sequence relative to the previously published sequence. This cDNA was expressed using a baculovirus expression system, and the resultant P450 had a lambda max of 450 nm when reduced and complexed with carbon monoxide. Specific content of the expressed P450 ranged from 0.27 to 0.43 nmol/mg of cell lysate protein. Arachidonic acid metabolism catalyzed by expressed CYP2C23 indicated that CYP2C23 efficiently produced epoxyeicosatrienoic acids (EETs). These EETs were characterized further by gas-liquid chromatography/negative ion chemical ionization mass spectrometry (GC/NCIMS) and were found to include 8,9-EET, 11,12-EET and 14,15-EET in a ratio of 1:2:1. No 5,6-EET was detected. A low rate of lauric acid hydroxylation at the (omega-1)-position was found, but the enzyme was unable to metabolize prostaglandin E1. These studies suggest that CYP2C23 is responsible, in part, for the production of EETs in rat kidney.

[Some problems of TS measurement after administration of fluoropyrimidines in colorectal cancer. Kinki Cooperative Study Group of Chemotherapy for Colorectal Carcinoma]

A joint multicenter comparative study of carmofur (HCFU) alone or HCFU+dipyridamole (DP) concurrent administration was conducted by the Kinki Colorectal Cancer Chemotherapy Society. In this study, the drugs were administered five days prior to surgery, and thymidylate synthetase (TS) inhibition rate at the primary lesion of colorectal cancer was determined. In addition, the effect of time after resection of the primary lesion before specimen cooling on the TS inhibition rate was investigated. The subjects were 87 registered patients who received colorectal cancer surgery during 4 months from October 1991 to January 1992. The time before postsurgical cooling was divided into four group; within 10 min (n = 67), 11-20 min (n = 8), 21-30 min (n = 7), and 31 min or longer (n = 5). The TS inhibition rates (mean +/- SD) were 0.45 +/- 0.22, 0.38 +/- 0.19, 0.30 +/- 0.21, and 0.04 +/- 0.05 respectively. The longer the time after resection of the primary lesion before specimen cooling, the more TS inhibition rate decreased. When the time before specimen cooling exceeds 30 min, the major part of TS combined with FdUMP exists in a free state. Therefore, it was considered not suitable as the material for the measurement.