Abstract 2257: DNA adductome analysis in human colorectal tissues

Due to recent advancement of DNA sequencing technologies, cancer genome analysis has shown that somatic mutations have different trends in various tissues and individuals. Some of trends has been associated with exposure of chemically reactive compounds derived from exogenous or endogenous sources and genetic deficiencies in DNA repair and DNA replication as mutational signatures. Accumulation of these information will ultimately expect to identify carcinogenic etiologies in an individual case. However, what types of DNA damage caused the mutational signatures and how extent they contribute to human carcinogenesis has not yet fully explained.To directly evaluate the chemical types of DNA damage in human colorectal tissues, we performed comprehensive identification of DNA adducts by a liquid chromatography coupled with mass spectrometry. In this DNA adductome methodology, genome DNA was enzymatically hydrolyzed into mononucleoside and separated using a reversed-phase chromatography. Chemical structure of DNA adducts including products of epigenetic modification in genome DNA was identified using column retention time and m/z of chemical standard library of DNA adducts. Peak areas of DNA adducts were normalized by that of naturally-occurring isotopologues of canonical DNA nucleoside and compared with clinicopathological information. We identified several DNA adducts in human colorectal tissue. These included DNA adducts of alkylation, oxidation, and lipid peroxidation. C5-methyl-2’-deoxycytidine was most abundant atypical DNA in human colorectal tissue and prevalent in all cases. C5-hydroxymethyl-2’-deoxycytdine was decreased in colorectal cancer cases compared with non-colorectal cancer cases. Other DNA adducts like 1,N6-etheno-2’-deoxyadenosine were present with group- or individual-specificity. Compared with our previous results of DNA adductome analysis in human stomach mucosae and kidney tissues, DNA adducts observed in human colorectal tissue showed some tissue specificity. We will discuss whether profiles of DNA adducts are based on similar contexts of chemical exposure among individuals. DNA adducts observed in our study potentially indicated chemical causes of DNA mutation in human colorectal tissue. We propose that the integration of DNA adductomics using mass spectrometric profiling with other genetic analysis such as mutational signature analysis leverage the exploration of chemical and genetic etiology in an individual carcinogenic context and evaluate gene-environment interaction in human carcinogenesis.

Citation Format: Yuji Iwashita, Shunsuke Ohtsuka, Ippei Ohnishi, Yuto Matsushita, Takashi Yamashita, Keisuke Inaba, Atsuko Fukazawa, Hideto Ochiai, Keigo Matsumoto, Nobuhito Kurono, Yoshitaka Matsushima, Hiroki Mori, Shioto Suzuki, Shohachi Suzuki, Fumihiko Tanioka, Haruhiko Sugimura. DNA adductome analysis in human colorectal tissues [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2257.

A DNA adductome analysis revealed a reduction in the global level of C5-hydroxymethyl-2'-deoxycytidine in the non-tumoral upper urinary tract mucosa of urothelial carcinoma patients

Background

DNA adducts, covalent modifications to DNA due to exposure to specific carcinogens, cause the mispairing of DNA bases, which ultimately results in DNA mutations. DNA methylation in the promoter region, another type of DNA base modification, alters the DNA transcription process, and has been implicated in carcinogenesis in humans due to the down-regulation of tumor suppressor genes. Difficulties are associated with demonstrating the existence of DNA adducts or chemically modified bases in the human urological system. Apart from aristolochic acid-DNA adducts, which cause urothelial carcinoma and endemic nephropathy in a particular geographical area (Balkan), limited information is currently available on DNA adduct profiles in renal cell carcinoma and upper urinary tract urothelial carcinoma, including renal pelvic cancer and ureteral cancer.

Method

To elucidate the significance of DNA adducts in carcinogenesis in the urothelial system, we investigated 53 DNA adducts in the non-tumoral renal parenchyma and non-tumoral renal pelvis of patients with renal cell carcinoma, upper urinary tract urothelial carcinoma, and other diseases using liquid chromatography coupled with tandem mass spectrometry. A comparative analysis of tissue types, the status of malignancy, and clinical characteristics, including lifestyle factors, was performed.

Results

C5-Methyl-2′-deoxycytidine, C5-hydroxymethyl-2′-deoxycytidine (5hmdC), C5-formyl-2′-deoxycytidine, 2′-deoxyinosine, C8-oxo-2′-deoxyadenosine, and C8-oxo-2′-deoxyguanosine (8-OHdG) were detected in the renal parenchyma and renal pelvis. 8-OHdG was more frequently detected in the renal pelvis than in the renal cortex and medulla (p = 0.048 and p = 0.038, respectively). 5hmdC levels were significantly lower in the renal pelvis of urothelial carcinoma patients (n = 10) than in the urothelium of patients without urothelial carcinoma (n = 15) (p = 0.010). Regarding 5hmdC levels in the renal cortex and medulla, Spearman’s rank correlation test revealed a negative correlation between age and 5hmdC levels (r = − 0.46, p = 0.018 and r = − 0.45, p = 0.042, respectively).

Conclusions

The present results revealed a reduction of 5hmdC levels in the non-tumoral urinary tract mucosa of patients with upper urinary tract urothelial carcinoma. Therefore, the urothelial cell epithelia of patients with upper urinary tract cancer, even in non-cancerous areas, may be predisposed to urothelial cancer.

Supplementary Information

The online version contains supplementary material available at 10.1186/s41021-021-00228-9.

Mass spectrometric profiling of DNA adducts in the human stomach associated with damage from environmental factors

Background

A comprehensive understanding of DNA adducts, one of the most plausible origins of cancer mutations, is still elusive, especially in human tissues in clinical settings. Recent technological developments have facilitated the identification of multiple DNA adducts in a single experiment. Only a few attempts toward this “DNA adductome approach” in human tissues have been reported. Geospatial information on DNA adducts in human organs has been scarce.

Aim

Mass spectrometry of human gastric mucosal DNA was performed to identify DNA adducts associated with environmental factors.

Materials and methods

From 59 subjects who had received gastrectomy for gastric cancer, 306 samples of nontumor tissues and 15 samples of tumors (14 cases) were taken for DNA adductome analysis. Gastric nontumor tissue from autopsies of 7 subjects without gastric cancer (urothelial cancer, hepatocellular carcinoma, lung cancer each; the other four cases were without any cancers) was also investigated. Briefly, DNA was extracted from each sample with antioxidants, digested into nucleosides, separated by liquid chromatography, and then electrospray-ionized. Specific DNA adducts were identified by mass/charge number and column retention time compared to standards. Information on lifestyle factors such as tobacco smoking and alcohol drinking was taken from the clinical records of each subject.

Results

Seven DNA adducts, including modified bases, C5-methyl-2′-deoxycytidine, 2′-deoxyinosine, C5-hydroxymethyl-2′-deoxycytidine, N6-methyl-2′-deoxyadenosine, 1,N6-etheno-2′-deoxyadenosine, N6-hydroxymethyl-2′-deoxyadenosine, and C8-oxo-2′-deoxyguanosine, were identified in the human stomach and characterized. Intraindividual differences according to the multiple sites of these adducts were noted but were less substantial than interindividual differences. N6-hydroxymethyl-2′-deoxyadenosine was identified in the human stomach for the first time. The amount of C5-hydroxymethyl-2′-deoxycytidine was higher in the stomachs of subjects without gastric cancer than in the nontumor and tumor portions of the stomach in gastric cancer patients. Higher levels of 1,N6-etheno-2′-deoxyadenosine were detected in the subjects who reported both smoking and drinking than in those without these habits. These DNA adducts showed considerable correlations with each other.

Conclusions

We characterized 7 DNA adducts in the nontumor portion of the human stomach in both gastric cancer subjects and nongastric cancer subjects. A reduction in C5-hydroxymethyl-dC even in the nontumor mucosa of patients with gastric cancer was observed. Smoking and drinking habits significantly influenced the quantity of one of the lipid peroxidation-derived adducts, etheno-dA. A more expansive DNA adductome profile would provide a comprehensive understanding of the origin of human cancer in the future.

Supplementary Information

The online version contains supplementary material available at 10.1186/s41021-021-00186-2.

High-resolution imaging of coronary calcifications by intense low-energy fluoroscopic X-ray obtained from synchrotron radiation

Purpose: To obtain an intense monochromatic low-energy X-ray from synchrotron radiation (SR) and apply it to detect coronary calcifications.

Methods and Results: The SR beam was reflected with a silicon crystal to be expanded (150 mm in height and 80 mm in width) and to be monochromatized at an energy level of 37 keV. The X-ray was intermittently irradiated to obtain dynamic imaging of 30 images/s. Images were recorded by a digital fluorography system. The low-energy X-ray from SR sharply visualized calcification of coronary arteries, while conventional X-ray could not visualize coronary calcification.

Conclusion: The intense monochromatic low-energy X-ray from SR is sensitive, has high-resolution for imaging coronary calcification and may serve as a screening method for coronary artery disease.

Kartagener's syndrome presenting in old age

It is considered that Kartagener's syndrome is caused by ciliary dysfunction. This syndrome is characterized by the clinical triad of bronchiectasis, sinusitis, and dextrocardia. We describe an elderly patient with Kartagener's syndrome who reached advanced age. We suppose that it may be possible for patients with Kartagener's syndrome to live a full span with optimal therapy for respiratory tract infection and control progression of this disease. Chronic Respiratory Disease 2007; 4: 75—76

Prolactin regulatory element binding protein as a potential transcriptional factor for the insulin gene in response to glucose stimulation

AIMS/HYPOTHESIS

Prolactin regulatory element binding (PREB) protein has been identified as a factor that regulates prolactin promoter activity in rat anterior pituitary. PREB is located not only in the anterior pituitary but also in pancreas; however its role in the pancreas is not known. We therefore examined the role of PREB in insulin gene expression.

MATERIALS AND METHODS

To analyse the effects of PREB on insulin gene transcription, we employed the luciferase reporter gene assay and electrophoretic mobility shift assay (EMSA). In cells expressing or knocked down for PREB, insulin expression and secretion were determined.

RESULTS

PREB was located mainly in nuclei of rat pancreatic beta cells and its cell line, INS-1. A nuclear extract of INS-1 cells contained material that was recognised by PREB antiserum. This nuclear extract also showed insulin promoter binding activity that was super-shifted by PREB antiserum in EMSA studies. In the INS-1 cells, co-expression of PREB and the insulin promoter induced activity of the latter. The addition of glucose to the cells increased PREB expression. Deletional analysis of the insulin promoter showed that A3, a glucose-responsive cis-element in the insulin promoter, mediated the transcriptional effect of PREB. In addition, synthesised PREB bound the A3 element by EMSA, while a mutant of this motif in the insulin promoter abrogated the effect of PREB. Cells expressing or knocked down for PREB exhibited increased or decreased insulin expression, respectively.

CONCLUSIONS/INTERPRETATION

These results demonstrate that PREB may contribute to the regulation of insulin gene transcription and insulin secretion in response to glucose stimulation.

Wolbachia and nuclear-nuclear interactions contribute to reproductive incompatibility in the spider mite Panonychus mori (Acari: Tetranychidae)

Maternally transmitted bacteria of the genus Wolbachia are obligate, intracellular symbionts that are responsible for cytoplasmic incompatibility in a wide range of arthropods such as insects and mites. Spider mites often show uni- and bidirectional incompatibilities among populations with and without Wolbachia. Therefore, we surveyed the presence of Wolbachia by PCR and then conducted crossing experiments among 25 populations of Panonychus mori to determine how Wolbachia are related to the incompatibility in this species. Five out of the 25 populations were infected with Wolbachia. These five populations were treated with an antibiotic (rifampicin) to eliminate Wolbachia. We carried out round-robin crosses among 20 Wolbachia-uninfected populations, five infected populations and five rifampicin-treated populations (30 x 30=900 crosses in total). Incompatibility among P. mori populations was caused by Wolbachia infection, nuclear-cytoplasmic interactions or nuclear-nuclear interactions. Wolbachia-mediated incompatibility was observed in crosses between uninfected females and infected males or between females and males harboring different Wolbachia strains. Nuclear-cytoplasmic interactions may be responsible for the unidirectional incompatibility in crosses between the two northern populations and one of the southern populations. Bidirectional incompatibility caused by nuclear-nuclear interactions was observed in 99 combinations of interpopulation crosses (99/300=0.33). Although no geographical trends were detected in the distribution of bidirectionally compatible populations, the results reveal a genetic divergence among P. mori populations.

Prolongation of islet allograft survival in mice by combined treatment with pravastatin and low-dose cyclosporine

Pravastatin, a 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitor, is known to have suppressive effects on immune and inflammatory cells. We have previously shown in mice and dogs that this agent prevents primary nonfunction of islet iso- and autografts by reducing inflammation at the graft site. The present study was designed to further investigate whether pravastatin has a synergistic effect with cyclosporine (Cs) to prolong islet allograft survival in mice. Unpurified 3000 BALB/c newborn islets were transplanted under the renal capsule of a streptozotocin-diabetic C57BL/6 mouse. Pravastatin and Cs were administered for 10 days starting on the day of grafting (day 0). Five groups were set up based on the treatment protocol: group 1, treatment with 40 mg/kg pravastatin; group 2, 30 mg/kg Cs; group 3, 50 mg/kg Cs; group 4, 40 mg/kg pravastatin and 30 mg/kg Cs; group 5, vehicle alone. Graft survival was indicated by blood glucose levels sustained at <200 mg/dl, and graft rejection by >250 mg/dl for 2 consecutive days. Hyperglycemia persisted in six of the eight (75%) mice and grafts were rejected in 3.6 +/- 0.5 days (mean +/- SD) in group 5. In group 1, grafts were also rejected in 3.8 +/- 0.8 days, but blood glucose was transiently <200 mg/dl in three of the five mice. Despite Cs, grafts were rejected between 7 and 15 days (10.3 +/- 2.4 days) in group 2. Among six mice in group 3, one maintained euglycemia for >60 days, the other rejected the graft on day 15, and the remaining four died with functioning grafts between 9 and 13 days due to Cs toxicity. A combination of a low dose of Cs and pravastatin (group 4) prolonged graft survival for >19 days in five of the eight mice, and for 7-13 days in the remaining three mice. Histological examination of the grafts in this group showed significantly reduced local inflammation. Results indicate a synergistic effect of pravastatin and Cs on prevention of islet allograft rejection.

Long-term effects of jejunal pouch added to Roux-en-Y reconstruction after total gastrectomy

BACKGROUND

Jejunal pouch reconstruction after total gastrectomy has been demonstrated to ameliorate postgastrectomy symptoms, with the process of adaptation taking several months. In contrast to the short-term effects of pouch reconstruction, there are few reports about the long-term consequences (more than 2 years after surgery).

METHODS

In this study, 22 patients with jejunal pouch (PRY group) and 12 patients without jejunal pouch (RY group) who survived for more than 2 years without any recurrence and were available for follow-up were compared. Patients in the two groups were compared 2 years after surgery in terms of postgastrectomy symptoms, and improvements in body weight and nutritional parameters.

RESULTS

Eating capacity at a single meal compared with that in the pre-illness state was significantly better in the PRY group than in the RY group. The total score on the gastrointestinal symptom rating scale (GSRS) in the PRY group was less than that in the RY group (3.17 vs 5.25). The GSRS score for reflux syndrome in the PRY group was significantly better than that in the RY group. Assessment according to Cuschieri's gradings revealed that the total score in the PRY group was lower than that in the RY group (2.73 vs 5.92). Among the various symptoms examined, the incidence of dietary restriction and that of heartburn were significantly lower in the PRY group.

CONCLUSION

We conclude that, 2 years after total gastrectomy, the pouch reconstruction had alleviated postgastrectomy symptoms to a greater extent than simple Roux-en-Y reconstruction, but the effectiveness could be improved. The long-term effects of pouch reconstruction should be examined more precisely with an adequate and valid scoring system for determining quality of life.

Sarcoidosis with giant parotomegaly

We report the case of a 63-year-old man with bilateral parotid gland sarcoidosis. Giant, elastic, hard, subcutaneous tumors had been present on the right parotic and submaxillary regions for 11 years and on the left for 1 year. The patient had had diabetes mellitus for 8 years. Noncaseating epithelioid cell granulomata were revealed histopathologically in the periductal area of the parotid gland. Bilateral hilar lymphadenopathy was noted on chest x-ray studies. Serum levels of lysozyme were increased. Levels of serum angiotensin-converting enzyme were within normal limits. Tuberculin skin reaction was positive. The tumors gradually improved after treatment with oral minocycline. Giant parotomegaly, as it occurred in this case, is very rare.

Conservative treatment of hemolytic complication following coil embolization in two adult cases of patent ductus arteriosus

Two adult cases of relatively large patent ductus arteriosus (PDA) were treated by coil embolization, but were complicated by hemolysis that was successfully managed by medical treatment. Case 1 was a 67-year-old woman and Case 2 was a 71-year-old woman with a PDA of minimal diameter of 5.3 mm and 5.5 mm, respectively. The approach was via the pulmonary artery and 2 coils were delivered simultaneously into the ductus, known as the 'kissing coil technique'. Although immediately after the procedure only a small residual shunt was revealed by aortogram, hemolysis occurred for several hours after the procedure in both cases. A hemolytic complication usually needs additional coil embolization or surgical treatment, but in these 2 cases it was successfully treated by haptoglobin infusion to prevent nephropathy and by antiplasmin infusion to promote thrombus formation. Hemolytic complications of coil embolization of PDA can managed by medication when the residual shunt is minimal and the degree of hemolysis is mild.

Increased islet viability by addition of beraprost sodium to collagenase solution

The digestion of pancreatic tissue with collagenase is an essential part of the islet isolation procedure. However, the process exposes islets to various types of harmful factors, including collagenase contaminants, enzymes released from the acinar cells, warm ischemia, and mechanical agitation. Nitrogen oxide production and cytokine release may also contribute to islet cell damage. Protection of islets from such damage would improve the islet yield, survival, and function. Beraprost sodium (BPS) is a prostaglandin I2 analogue, is stable in aqueous solution, and has a cytoprotective effect on various types of cells. BPS has been shown to improve the yield and function of cryopreserved and/or cultured islets. These findings prompted us to examine its cytoprotective effect on islets during the islet isolation process. Canine islets were isolated by means of a two-step digestion method and purified on Euro-Ficoll density gradient solutions (the procedure used for human islets). BPS at a concentration of 100 nM was added to the collagenase solution. After purification, the islet yield was 434,561 +/- 35.691 islet number expressed as 150 microm equivalent size (IEQ)/pancreas or 8,799 +/- 345 IEQ/g of pancreas in the BPS group and 349,987 +/- 52,887 IEQ/pancreas or 7,998 +/-1610 IEQ/g of pancreas in the control group (n = 8, each). The percent viability was 88.5 +/- 0.7% in the BPS group and 82.0 +/-0.9% in the control group (P < 0.01). Therefore, the recovery of viable islets (calculated by islet number x % viability) was 384,586 +/- 46,804 IEQ/pancreas (7,743 IEQ/g) in the BPS group and 286,989 +/- 43,367 IEQ/pancreas (6,558 IEQ/g) in the control group (P < 0.02). After culture, significantly higher numbers of islets were also recovered in the BPS group than in the control group. The islet insulin content was significantly higher in the BPS group than controls (237.8 +/- 38.5 versus 92.3 +/- 25.6 microU/IEQ; P < 0.02), although islets of both groups responded with high stimulation indices (>6). These results indicate that the addition of BPS to the collagenase solution increases the recovery of viable islets, and improves beta cell function.

Schedule-dependent combined sensitivity testing of anti-cancer agents in human gastric carcinoma cell lines

The efficacy of combination chemotherapy for gastric carcinoma has been unsatisfactory, although the prognosis of advanced and recurrent disease has improved with the introduction of cisplatin (CDDP). This study examines the effect of the anti-cancer therapies CDDP, doxorubicin (ADM) and etoposide (VP-16) on the cell cycle and their cytotoxicity against two gastric carcinoma cell lines: MKN-28 (well differentiated) and MKN-45 (poorly differentiated). The treatments have different cytocidal mechanisms, and they were studied in dual combinations. For all combinations studied, cytotoxicity against MKN-45 was higher than against MKN-28. For ADM plus CDDP, or ADM plus VP-16, cytotoxicity was higher in patients pretreated with ADM than other regimens. The highest anti-tumour activity against both cell lines was obtained with ADM followed by CDDP (we have obtained good clinical results with this regimen). Schedule-dependent combined sensitivity testing of anti-cancer agents will be useful for the clinical application of therapies.

Norepinephrine release is increased in the hibernating heart, studied in a chronic canine model of myocardial hibernation

We examined the change in cardiac sympathetic function in the hibernating heart. To induce hibernating hearts in dogs, we placed a nylon tube via the carotid artery in the left circumflex artery (LCx) and obstructed the LCx flow. The plasma norepinephrine (NE) and epinephrine (E) concentrations in the coronary sinus and the aorta were measured before and 1 week after the tube placement to evaluate the catecholamine release from the heart. The wall motion was followed by echocardiography and. 1 week after the tube placement, regional myocardial blood flow (RBF) was measured using colored microspheres. Also. the restorability of myocardial dysfunction was examined in other dogs by extracting the LCx tube 1 week after the placement. Finally, the heart was removed for pathological observation and dogs showing myocardial infarction were excluded. One week after placing the tube, wall thickening was reduced in the LCx area, but was not in the left anterior descending (LAD) area. Compared with the LAD area, RBF in the LCx area was decreased in the endocardium (p < 0.05), but was not in the epicardium. In other dogs, the reduced wall thickening in the LCx area was restored to normal levels 1 or 2 weeks after the tube extraction. Thereby, our dogs with the tube placed were considered to be models of myocardial hibernation. The plasma NE and E concentrations were not significantly changed by placing the tube, but NE release from the heart was increased after the tube placement (p < 0.05). E uptake from the heart did not differ. Therefore, it is suggested that NE release is increased in the hibernating heart and may contribute to its mechanism.

Nodular thickening of interlobar fissures: an early manifestation of malignant mesothelioma: a case report

Two men with occupational exposure to asbestos were admitted to our hospital with minute pleural changes on their chest CT image. Conventional computed tomography (CT) scans of the chest showed slightly thickened interlobar fissures and a small amount of pleural effusion. In addition, high-resolution CT showed small nodular opacities on interlobar fissures. There were no intrapulmonary mass shadows, pleural plaques or other extrapulmonary mass shadows. These roentgenographical findings were very similar to each other. Hyarulonic acid values obtained from their pleural fluid were extremely high. Finally, we diagnosed them as having malignant mesothelioma using an immunocytochemical technique and electronmicroscopy. We conclude that HRCT is helpful in the diagnosis of malignant mesothelioma, particularly in its early manifestation such as nodular opacities of interlobar fissures.

Proteomic analysis of the small intestine and colon epithelia of adenomatous polyposis coli gene-mutant mice by two-dimensional gel electrophoresis

Mutations of the adenomatous polyposis coli gene (APC) have been implicated in the occurrence of sporadic colon cancer. Various APC mutant strains of mice have been created to better understand the function of this gene. Previously, we had mice express a mutant form of mRNA of the APC protein that encoded 474 amino acids instead of the 2845 amino acids due to exon duplication. These APC mutant mice (APC delta 474) developed intestinal and mammary tumors, as have other APC mutant mice previously reported (Sasai, H., et al. Carcinogenesis, in press). To elucidate the mechanism of the tumor development, we prepared protein samples from both normal and tumor tissues from APC delta 474 mutant mice, as well as tissues from normal mice, and used them for proteomic analysis. After two-dimensional electrophoresis, the gels were silver stained and the protein spots were analyzed. We analyzed about 1000 protein spots per sample and found several protein spots that are specific for normal or tumor samples from APC delta 474 mutant mice, as well as proteins with altered expression levels. Among the identified protein spots, truncated beta-tubulins were specific to APC delta 474 mutant mice polyp samples. The apparent molecular mass of these proteins suggested that these beta-tubulins may be truncated very close to the binding site of the anti-tumor drug taxol.

Life threatening coronary artery spasm in childhood Kimura's disease

A 13 year old boy is described with hypereosinophilia associated with Kimura's disease, who showed repeated life threatening syncopal attacks during daily activities or at rest. Coronary arteriography demonstrated small aneurysms with irregular vessel walls of both coronary arteries, and the absence of organic stenotic lesions. Infusion of a minimal dose of ergonovine into the right coronary artery induced severe spasm of the vessel. Ventricular fibrillation recurred even after administration of nifedipine and isosorbide was started, but was completely inhibited by prednisolone.

Proteomic analysis of the small intestine and colon epithelia of adenomatous polyposis coli gene-mutant mice by two-dimensional gel electrophoresis

Mutations of the adenomatous polyposis coli gene (APC) have been implicated in the occurrence of sporadic colon cancer. Various APC mutant strains of mice have been created to better understand the function of this gene. Previously, we had mice express a mutant form of mRNA of the APC protein that encoded 474 amino acids instead of the 2845 amino acids due to exon duplication. These APC mutant mice (APC delta 474) developed intestinal and mammary tumors, as have other APC mutant mice previously reported (Sasai, H., et al. Carcinogenesis, in press). To elucidate the mechanism of the tumor development, we prepared protein samples from both normal and tumor tissues from APC delta 474 mutant mice, as well as tissues from normal mice, and used them for proteomic analysis. After two-dimensional electrophoresis, the gels were silver stained and the protein spots were analyzed. We analyzed about 1000 protein spots per sample and found several protein spots that are specific for normal or tumor samples from APC delta 474 mutant mice, as well as proteins with altered expression levels. Among the identified protein spots, truncated beta-tubulins were specific to APC delta 474 mutant mice polyp samples. The apparent molecular mass of these proteins suggested that these beta-tubulins may be truncated very close to the binding site of the anti-tumor drug taxol.

High-resolution imaging of coronary calcifications by intense low-energy fluoroscopic X-ray obtained from synchrotron radiation

PURPOSE

To obtain an intense monochromatic low-energy X-ray from synchrotron radiation (SR) and apply it to detect coronary calcifications.

METHODS AND RESULTS

The SR beam was reflected with a silicon crystal to be expanded (150 mm in height and 80 mm in width) and to be monochromatized at an energy level of 37 keV. The X-ray was intermittently irradiated to obtain dynamic imaging of 30 images/s. Images were recorded by a digital fluorography system. The low-energy X-ray from SR sharply visualized calcification of coronary arteries, while conventional X-ray could not visualize coronary calcification.

CONCLUSION

The intense monochromatic low-energy X-ray from SR is sensitive, has high-resolution for imaging coronary calcification and may serve as a screening method for coronary artery disease.

A novel human gene encoding HECT domain and RCC1-like repeats interacts with cyclins and is potentially regulated by the tumor suppressor proteins

Cyclin E-Cdk2 is an evolutionary conserved cyclin-dependent kinase (CDK) complex that drives the G1 to S phase transition of the cell cycle. A novel cDNA encoding a HECT family protein also containing RCC1-like repeats was isolated by a yeast two-hybrid screening using both cyclin E and its inhibitor p21. The protein product of this cDNA, Ceb1, interacts with various cyclin subunits of CDKs in mammalian cells. Expression of Ceb1 is specifically detected in testis and ovary and is highly elevated when the functions of the tumor suppressor proteins, p53 and RB, are compromised by mutations or viral oncoproteins. The present results suggest that Ceb1 may play a critical role when its expression and the CDK activity are upregulated by inactivation of p53 and RB.

Chronic antisense therapy for angiotensinogen on cardiac hypertrophy in spontaneously hypertensive rats

OBJECTIVE

We examined the effect of the suppression of plasma angiotensinogen (AGT) by the intravenous injection of antisense oligodeoxynucleotides (ODNs) against AGT targeted to the liver on cardiac remodeling in spontaneously hypertensive rats (SHR). The ODNs against rat AGT were coupled to asialoglycoprotein (ASOR) carrier molecules, which serve as an important method for regulating liver gene expression.

METHODS

Male SHR (n = 18), and age-matched male Wistar-Kyoto rats (WKY, n = 6) were used for this study. At 10 weeks of age, the SHR were divided into three groups (each group n = 6), and the systolic blood pressure (SBP) did not significantly change among them. The control SHR and WKY groups received saline, the sense SHR group was injected with the sense ODNs complex and the antisense SHR group was injected with the antisense ODNs complex, from 10 to 20 weeks of age. ASOR-poly(L)lysine-ODNs complex was injected via the tail veins twice a week.

RESULTS

At the end of the treatment, a reduction of hepatic AGT mRNA, cardiac angiotensin II type 1 receptor mRNA and the plasma AGT concentration was only observed in the antisense-injected SHR but not in the other groups of SHR and WKY. This antisense therapy did not significantly change the mRNA expression for angiotensin converting enzyme, angiotensin II type 2 receptor and AGT in the left ventricle (LV) among all three groups. Although the plasma angiotensin II (Ang II) concentration significantly decreased to the level of WKY after the antisense therapy, the SBP, LV to body weight ratio and % collagen volume fraction also showed a reduction, however, these findings were still larger than in the WKY than in either the sense-injected SHR or control SHR.

CONCLUSION

The plasma AGT is considered to play a role in the development of cardiac hypertrophy in SHR, but it has not a complete effects on cardiac remodeling even if the plasma Ang II levels are inhibited because of an insufficient suppression of hypertension.

Cloning and characterization of a novel p21(Cip1/Waf1)-interacting zinc finger protein, ciz1

p21(Cip1/Waf1) inhibits cell-cycle progression by binding to G1 cyclin/CDK complexes and proliferating cell nuclear antigen (PCNA) through its N- and C-terminal domains, respectively. Here, we report a novel p21(Cip1/Waf1)-interacting protein, Ciz1 (for Cip1 interacting zinc finger protein), which contains polyglutamine repeats and glutamine-rich region in the N-terminus as well as three zinc-finger motifs and one MH3 (matrin 3-homologous domain 3) in the C-terminal region. Ciz1 bound to the N-terminal, the CDK2-interacting part of p21(Cip1/Waf1), and the interaction was disrupted by the overexpression of CDK2. A region of about 150 amino acids containing the first zinc-finger motif in Ciz1 was the binding site for p21(Cip1/Waf1). When Ciz1 and p21(Cip1/Waf1) were individually overexpressed in U2-OS cells, they mostly localized in the nucleus. However, coexpression of Ciz1 induced cytoplasmic distribution of p21(Cip1/Waf1). These data indicate that Ciz1 is a unique nuclear protein that regulates the cellular localization of p21(Cip1/Waf1).

Improved recovery of cryopreserved canine islets by use of beraprost sodium

Cryopreservation of pancreatic islets provides many advantages for clinical transplantation. Unfortunately, the freezing and thawing processes lead to a significant loss of islets. In this study, an attempt was made to increase the yield and viability of islets after cryopreservation and thawing. By using canine islets, we evaluated whether beraprost sodium (BPS), a stable prostacyclin analog, protects islets during the freeze-thaw processes and improves the recovery of frozen-thawed islets. Canine islets were frozen and thawed by the procedures used routinely for storage of human islets. In this study, we deliberately used islets of lower purity (60+/-3.6%), which is undesirable for cryopreservation. The recovery of viable islets after thawing is poorer with islets of lower purity than with highly purified islets. BPS was added to both the cryopreservation solutions containing dimethyl sulfoxide (DMSO) and the thawing solution containing sucrose. After thawing, the islet recovery (islet number after thawing divided by islet number before freezing) was 71.1+/-12.7% with 1 nM BPS, 77.8+/-5.6% with 10 nM BPS, 79.3+/-6.7% with 100 nM BPS, and 69.2+/-7.2% in control preparations without BPS. Islet viability assessed by supravital staining was 57.5+/-5.6%, 64.7+/-7.0%, 67.5+/-6.5%, and 57.7+/-4.9% with 1 nM, 10 nM, and 100 nM BPS and controls, respectively. Both islet recovery and viability were significantly better with 10 nM and 100 nM BPS than with the controls (p<0.03). After 3 days in culture, islet numbers in the 10 nM and 100 nM BPS groups were significantly higher and showed better insulin-release responses than those from the 1 nM BPS and control groups. Histologically, islet structure was well preserved in the 10 nM and 100 nM BPS groups, whereas many islets of the control group were smaller and fragmented. Electron microscopic examination revealed that 10 nM and 100 nM BPS preserved the microstructure of islet cells, and signs of apoptosis or necrosis were rare. It was concluded that BPS improved the recovery and viability of canine islets after cryopreservation and thawing. BPS would be a useful agent for improving the recovery of cryopreserved human islets for clinical transplantation.

Suppression of STAT5 functions in liver, mammary glands, and T cells in cytokine-inducible SH2-containing protein 1 transgenic mice

Various cytokines utilize Janus kinase (JAK) and the STAT (signal transducers and activators of transcription) family of transcription factors to carry out their biological functions. Among STATs, two highly related proteins, STAT5a and STAT5b, are activated by various cytokines, including prolactin, growth hormone, erythropoietin, interleukin 2 (IL-2), and IL-3. We have cloned a STAT5-dependent immediate-early cytokine-responsive gene, CIS1 (encoding cytokine-inducible SH2-containing protein 1). In this study, we created CIS1 transgenic mice under the control of a beta-actin promoter. The transgenic mice developed normally; however, their body weight was lower than that of the wild-type mice, suggesting a defect in growth hormone signaling. Female transgenic mice failed to lactate after parturition because of a failure in terminal differentiation of the mammary glands, suggesting a defect in prolactin signaling. The IL-2-dependent upregulation of the IL-2 receptor alpha chain and proliferation were partially suppressed in the T cells of transgenic mice. These phenotypes remarkably resembled those found in STAT5a and/or STAT5b knockout mice. Indeed, STAT5 tyrosine phosphorylation was suppressed in mammary glands and the liver. Furthermore, the IL-2-induced activation of STAT5 was markedly inhibited in T cells in transgenic mice, while leukemia inhibitory factor-induced STAT3 phosphorylation was not affected. We also found that the numbers of gamma delta T cells, as well as those of natural killer (NK) cells and NKT cells, were dramatically decreased and that Th1/Th2 differentiation was altered in transgenic mice. These data suggest that CIS1 functions as a specific negative regulator of STAT5 in vivo and plays an important regulatory role in the liver, mammary glands, and T cells.

Radiofrequency catheter ablation of idiopathic right ventricular tachycardia near the His bundle

There are only a few reports on successful radiofrequency catheter ablation of idiopathic right ventricular tachycardia (VT) originating from other sites than right ventricular outflow tract. We report here a case of VT which exhibited an inferior-axis and a left bundle branch block pattern and originated near the His bundle. Using the temperature-controlled ablation catheter, prudent observation of the fluoroscopy and intracardiac electrograms during pacemapping, we successfully ablated the origin of the VT without any conduction disturbance. However, further study is required to determine the effectiveness of catheter ablation and the long term prognosis for this type of VT.

MDM2 interacts with MDMX through their RING finger domains

The N-terminus of MDM2 proto-oncoprotein interacts with p53 and down modulates p53 activity by inhibiting transcriptional activity and promoting p53 degradation. MDMX is structurally related to MDM2 and also binds to p53. However, the function of MDMX has not been clarified yet. We found that MDM2 hetero-oligomerized with MDMX through their C-terminal RING finger domains. Yeast two-hybrid analysis revealed that the hetero-oligomerization between MDMX and MDM2 was more stable than the homo-oligomerization of each protein. MDM2 has been shown to be degraded by the ubiquitin-proteasome pathway, while MDMX was a stable protein. Interaction of MDMX with MDM2 through the C-terminal RING finger domains resulted in inhibiting degradation of MDM2. These data indicate that MDMX functions as a regulator of MDM2.

The JAK-binding protein JAB inhibits Janus tyrosine kinase activity through binding in the activation loop

The Janus family of protein tyrosine kinases (JAKs) regulate cellular processes involved in cell growth, differentiation and transformation through their association with cytokine receptors. However, compared with other kinases, little is known about cellular regulators of the JAKs. We have recently identified a JAK-binding protein (JAB) that inhibits JAK signaling in cells. In the studies presented here we demonstrate that JAB specifically binds to the tyrosine residue (Y1007) in the activation loop of JAK2, whose phosphorylation is required for activation of kinase activity. Binding to the phosphorylated activation loop requires the JAB SH2 domain and an additional N-terminal 12 amino acids (extended SH2 subdomain) containing two residues (Ile68 and Leu75) that are conserved in JAB-related proteins. An additional N-terminal 12-amino-acid region (kinase inhibitory region) of JAB also contributes to high-affinity binding to the JAK2 tyrosine kinase domain and is required for inhibition of JAK2 signaling and kinase activity. Our studies define a novel type of regulation of tyrosine kinases and might provide a basis for the design of specific tyrosine kinase inhibitors.

APS, an adaptor protein containing PH and SH2 domains, is associated with the PDGF receptor and c-Cbl and inhibits PDGF-induced mitogenesis

Previously we cloned a novel adaptor protein, APS (adaptor molecules containing PH and SH2 domains) which was tyrosine phosphorylated in response to c-kit or B cell receptor stimulation. Here we report that APS was expressed in some human osteosarcoma cell lines, markedly so in SaOS-2 cells, and was tyrosine-phosphorylated in response to several growth factors, including platelet derived growth factor (PDGF), insulin-like growth factor (IGF), and granulocyte-macrophage colony stimulating factor (GM-CSF). Ectopic expression of the wild type APS, but not C-terminal truncated APS, in NIH3T3 fibroblasts suppressed PDGF-induced MAP kinase (Erk2) activation, c-fos and c-myc induction as well as cell proliferation. In vitro binding experiments suggest that APS bound to the beta type PDGF receptor, mainly via phosphotyrosine 1021 (pY1021). Indeed, tyrosine phosphorylation of PLC-gamma, which has been demonstrated to bind to pY1021, but not that of PI3 kinase and associated proteins, was reduced in APS transformants. PDGF induced phosphorylation of the tyrosine residue of APS close to the C-terminal end. In vitro and in vivo binding experiments indicate that the tyrosine phosphorylated C-terminal region of APS bound to c-Cbl, which has been shown to be a negative regulator of tyrosine kinases. Since coexpression of c-Cbl with wild type APS, but not C-terminal truncated APS, synergistically inhibited PDGF-induced c-fos promoter activation, c-Cbl could be a mechanism of inhibitory action of APS on PDGF receptor signaling.

Dynamic intravenous coronary angiography using 2D monochromatic synchrotron radiation

A method of examination for coronary artery disease that is less invasive and easier than coronary angiography (CAG) has been sought. We have developed a dynamic intravenous coronary angiography (IVCAG) system using synchrotron radiation (SR) and have used it clinically. Four patients suspected of having angina pectoris underwent IVCAG. An SR beam was reflected asymmetrically with a silicon crystal to produce a wide (150 mm x 80 mm) and monochromatic (37 keV) X-ray beam, with an energy level to achieve high sensitivity to the contrast agent. Following an intravenous injection of contrast agent, irradiation was applied for 4 ms periods at 33 ms intervals for dynamic IVCAG at 30 images s-1. Images were acquired with an image intensifier and recorded with a digital fluorography system. The dynamic images permitted clear visualization of the coronary arteries and permitted evaluation of coronary anatomy. Two patients exhibited no stenotic lesions, one patient had a 90% stenosis in the right coronary artery, and the remaining patient had a 25% stenosis at the site of previous percutaneous transluminal coronary angioplasty in the left anterior descending artery (LAD). The total irradiation doses used for IVCAG were less than those for conventional angiography. Dynamic IVCAG can be readily used for the evaluation of coronary arteries.

Natriuretic peptides in the lung modulated by pneumonectomy

BACKGROUND

Natriuretic peptides are vasodilator hormones involved in the regulation of blood pressure and volume homeostasis. However, the mechanism of these peptides after pneumonectomy remains obscure.

METHODS

We investigated changes in the pulmonary arterial pressure and the localization and changes in the atrial (A-type) natriuretic peptide (ANP) and the C-type natriuretic peptide (CNP) in the lung, using immunohistochemistry and radioimmunoassay (RIA) in anesthetized dogs. Furthermore, we examined guanosine 3', 5'-monophosphate (cGMP) levels in plasma and in the contralateral lung.

RESULTS

Pulmonary arterial pressure was significantly increased after pneumonectomy. The immunoreactivities of both ANP and CNP were detected in the endothelium of the pulmonary artery. In the contralateral lung, the concentrations of ANP and CNP were both significantly increased. In plasma, only ANP levels were significantly increased. In contrast, the plasma and lung cGMP levels were significantly reduced after pneumonectomy.

CONCLUSIONS

We postulate that the processes from secretion in the vascular endothelial cells to the action via ANP and CNP receptors are effected in the contralateral lung tissue at the acute stage of pneumonectomy.

Randomized, double-blind, placebo-controlled study of carvedilol on the prevention of nitrate tolerance in patients with chronic heart failure

OBJECTIVES

This study was designed to evaluate the effect of carvedilol on nitrate tolerance in patients with chronic heart failure.

BACKGROUND

The attenuation of cyclic guanosine 5'-monophosphate (cGMP) production due to inactivation of guanylate cyclase by increased superoxide has been reported as a mechanism of nitrate tolerance. Carvedilol has been known to combine alpha/beta-blockade with antioxidant properties.

METHODS

To evaluate the effect of carvedilol on nitrate tolerance, 40 patients with chronic heart failure were randomized to four groups that received either carvedilol (2.5 mg once a day [carvedilol group, n=10]), metoprolol (30 mg once a day [metoprolol group, n=10]), doxazosin (0.5 mg once a day [doxazosin group, n=10]) or placebo (placebo group, n=10). Vasodilatory response to nitroglycerin (NTG) was assessed with forearm plethysmography by measuring the change in forearm blood flow (FBF) before and 5 min after sublingual administration of 0.3 mg NTG, and at the same time blood samples were taken from veins on the opposite side to measure platelet cGMP. Plethysmography and blood sampling were obtained serially at baseline (day 0); 3 days after carvedilol, metoprolol, doxazosin or placebo administration (day 3); and 3 days after application of a 10-mg/24-h NTG tape concomitantly with carvedilol, metoprolol, doxazosin or placebo (day 6).

RESULTS

There was no significant difference in the response of FBF (%FBF) and cGMP (%cGMP) to sublingual NTG on day 0 and day 3 among the four groups. On day 6, %FBF and %cGMP were significantly lower in the metoprolol, doxazosin and placebo groups than on day 0 and day 3, but these parameters in the carvedilol group were maintained.

CONCLUSIONS

These results indicated that carvedilol may prevent nitrate tolerance in patients with chronic heart failure during continuous therapy with NTG.

Preventive effects of carvedilol on nitrate tolerance--a randomized, double-blind, placebo-controlled comparative study between carvedilol and arotinolol

OBJECTIVES

This study was designed to compare the preventive efect of nitrate tolerance between carvedilol with antioxidant properties and arotinolol without antioxidant properties.

BACKGROUND

The attenuation of cyclic guanosine monophosphate (cGMP) production due to inactivation of guanylate cyclase by increased superoxide has been reported as a mechanism of nitrate tolerance. Carvedilol has been known to combine alpha- and beta-blockade with antioxidant properties.

METHODS

To evaluate the preventive effect of nitrate tolerance, 24 patients with untreated hypertension were randomized to receive either carvedilol (10 mg twice a day [carvedilol group, n=8]), arotinolol (10 mg twice a day [arotinolol group, n=8]), or placebo (placebo group, n=8). Vasodilatory response to nitroglycerin (NTG) was assessed with forearm plethysmography by measuring the change in forearm blood flow (FBF) before and 5 min after sublingual administration of 0.3 mg NTG, and at the same time blood samples were taken from veins on the opposite side to measure platelet cGMP. Plethysmography and blood sampling were obtained serially at baseline (day 0), 3 days after carvedilol, arotinolol or placebo administration (day 3) and 3 days after application of a 20 mg/24 h NTG tape concomitantly with carvedilol, arotinolol or placebo (day 6).

RESULTS

There was no significant difference in the response of FBF (%FBF) and cGMP (%cGMP) to sublingual administration of NTG on days 0 and 3 among the three groups. On day 6, %FBF and %cGMP were significantly lower in the arotinolol group and the placebo group than days 0 and 3, but these parameters in the carvedilol group were maintained.

CONCLUSIONS

The results indicated that carvedilol with antioxidant properties may prevent the development of nitrate tolerance during continuous therapy with NTG compared with arotinolol without antioxidant properties.

Efficacy and rebound phenomenon related to intermittent nitroglycerin therapy for the prevention of nitrate tolerance

Intermittent transdermal therapy of nitroglycerin (NTG) has been recommended for the prevention of nitrate tolerance, but a rebound phenomenon has been reported to occur following removal of the NTG tape. The present study investigated the effects of intermittent NTG therapy on vasodilatory response and the intracellular production of cyclic GMP (cGMP). The study group comprised 12 healthy adults and measurements were taken of the platelet cGMP level, the venous volume (VV) (by forearm plethysmography) and the plasma levels of neurohormonal factors before and 5 min after administration of 0.3 mg of sublingual nitroglycerin (NTG) during the following 4 phases: (i) the control phase (8.00 h); (ii) the continuous phase (8.00 h; 7 days after continuous application of a 10 mg/24 h NTG tape); (iii) the intermittent application phase (8.00 h; 7 days after intermittent application of NTG tape, applied at 21.00 h and removed at 9.00 h); and (iv) the intermittent removal phase (13.00 h; 4 h after removal of the NTG tape in the intermittent phase). The percentage increase in cGMP (%cGMP) and venous volume (%VV) were significantly lower in the continuous phase than the control phase, but there was no difference between the control and the intermittent application phases. However, in the intermittent removal phase, the cGMP level before sublingual NTG, the %cGMP and the %VV were unchanged, but the VV before sublingual NTG was significantly lower than in the control phase. Plasma renin activity and the plasma level of angiotensin II were significantly increased in the continuous phase, the intermittent application phase, and the intermittent removal phase. In conclusion, intermittent transdermal NTG therapy prevented nitrate tolerance in the production of cGMP and vasodilation, but induced a rebound phenomenon after removal of the NTG tape. The rebound phenomenon following the tape removal may be related to some other mechanism, such as activation of neurohormonal factors.

Prevention of primary islet isograft nonfunction in mice with pravastatin

BACKGROUND

Nonspecific inflammatory damage in the early stages of transplantation is the major cause of primary islet graft nonfunction. Using murine isografts, we attempted to prevent this islet graft damage by treating recipients with pravastatin (Pravacol), a 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitor. Nicotinamide was also tested to determine the synergistic effect of both agents.

METHODS

Unpurified newborn BALB/c islets, ranging in number from 1800 to 2500, were transplanted into the left renal subcapsular space of a syngeneic adult mouse made diabetic with streptozotocin. Recipient mice were divided into the following four groups, based on treatment protocols: treatment with 40 mg/kg pravastatin (group 1), 500 mg/kg nicotinamide (group 2), 40 mg/kg pravastatin and 500 mg/kg nicotinamide (group 3), and vehicle alone (group 4). Pravastatin and nicotinamide were administered orally every day for 14 days, starting on the day of transplantation (day 0). Nonfasting blood glucose levels, urine glucose levels, and the intravenous glucose tolerance test were used to monitor the diabetic state. The reversal of diabetes was defined by normoglycemia and negative urine glucose maintained for more than 7 days.

RESULTS

After islet transplantation, levels of blood and urine glucose were significantly lower in groups 1 and 3, compared with those in group 4. K-values of an intravenous glucose tolerance test performed on day 14 were significantly higher in groups 1 and 3 than those of group 4. Reversal of diabetes had occurred in 63% of mice in group 1 and 67% in group 3, levels that were higher than those in group 2 (17%) and group 4 (0%) (P<0.02, groups 1 and 3 vs. group 4). Histological examination of grafts, biopsied on day 21, revealed well preserved islets with little sign of inflammation in groups 1 and 3, whereas grafts in groups 2 and 4 contained broken, smaller islets surrounded by severe fibrosis and mononuclear cell infiltration.

CONCLUSION

Our results in mice have shown the effectiveness of pravastatin for protecting islets from nonspecific inflammatory damage. Nicotinamide did not show a synergistic effect with pravastatin at the dosage used in this study. These results indicate that pravastatin may be a useful agent for clinical islet transplantation.

Platycopia compacta n. sp., the Second Species of Platycopioida (Crustacea: Copepoda) in the Indo-Pacific Region, with Remarks on Development, Feeding, Swimming, and Zoogeography

Platycopia compacta new species (Copepoda: Platycopioida) is described from the hyperbenthic zone in the Tokara Islands, southern Japan. This is the second species of the order in the Indo-Pacific region, and the eighth species of the genus. The present new species is distinguishable from the closely related P. inornata from the Bahamas by (1) the formation of allobasis in the antenna; (2) two unequal setae on the basal exite of the maxillule; (3) the intermaxillipedal process with only 3 pairs of prominences at tip; (4) the fusion of the coxa and basis in leg 3; and (5) the fusion of the second and third endopod segments in female legs 3-5. Copepodid stages III, V, and VI are compared with those of P. orientalis collected from Okinawa, and differ in the developmental patterns of the antennule and legs. The presence of an intermaxillipedal process and gut content analysis revealed that Platycopia is carnivorous. The armature of legs 2-5 of the hyperbenthic genus Platycopia is stouter than that of cavernicolous platycopioids, which indicates that Platycopia may penetrate into loose sediment, whereas the latter group might be more adapted to pelagic life. The horizontal distribution of the genus Platycopia apparently exhibits a full Tethyan track.

Preventive effects of angiotensin-converting enzyme inhibitors on nitrate tolerance during continuous transdermal application of nitroglycerin in patients with chronic heart failure

This study was designed to investigate the effect of angiotensin-converting enzyme (ACE) inhibitors with and without a sulfhydryl group on intracellular production of cGMP, forearm blood flow, and neurohormonal factors during continuous transdermal application of nitroglycerin in patients with chronic heart failure. Platelet cGMP level and forearm blood flow were measured before and 5 min after sublingual administration of nitroglycerin (NTG) in 20 patients with chronic heart failure during the following 4 phases: (1) baseline phase; (2) NTG phase (1 week after NTG tape 10 mg/day); (3) CPT phase (1 week after both captopril 37.5 mg/day and NTG tape 10 mg/day); and (4) ENL phase (1 week after both enalapril 5 mg/day and NTG tape 10 mg/day). The platelet GMP level before sublingual NTG and forearm blood flow were significantly higher during the 3 phases with NTG tape than during the control phase. The percent increases in platelet cGMP level and forearm blood flow after sublingual NTG were significantly lower during the NTG phase than during the baseline phase. In contrast, concomitant application of ACE inhibitors maintained the percent increase in platelet cGMP level and forearm blood flow. These results indicate that concomitant therapy with ACE inhibitors may be helpful in preventing the attenuation of intracellular cGMP production in patients with chronic heart failure during continuous transdermal application of NTG.

Establishment of a concordant xenogeneic splenocyte injection model for the dynamic study of the marginal zone in the spleen

BACKGROUND

This study was undertaken to establish a simple technique with which we could investigate the relationship between the marginal zone (MZ) in the spleen and antispecies antibody production, as well as to estimate the efficacy of various immunosuppressive treatments in xenotransplantation.

METHODS

With a concordant xenogeneic combination (hamster-to-rat), the early phase reaction of the MZ was studied by use of quantitative histologic analysis, and complement-dependent cytotoxic antibody titers were determined in both a heart transplantation model and the splenocyte injection model. Furthermore, changes in the MZ were examined with isogeneic and allogeneic combinations with the splenocyte injection model. Next, the effect of cyclophosphamide, a promising immunosuppressant for concordant xenotransplantation, was examined by use of the splenocyte injection model.

RESULTS

With a concordant xenogeneic combination, the MZ enlarged, and antihamster immunoglobulin M antibody synthesis increased after immunization in both models. On the other hand, with an isogeneic combination, the MZ did not expand, and with an allogeneic combination the MZ enlargement was not as great as that with a concordant xenogeneic combination. Cyclophosphamide suppressed the MZ expansion in a dose-dependent manner and effectively diminished antibody production in the splenocyte injection model.

CONCLUSION

Dynamic studies of the MZ in the spleen with the splenocyte injection model are useful for the elucidation of the mechanisms of reaction and for estimating the efficacy of various immunosuppressive treatments in concordant xenotransplantation.