Recent progress in metal assisted multicomponent reactions in organic synthesis

To prepare complicated organic molecules, straightforward, sustainable, and clean methodologies are urgently required. Thus, researchers are attempting to develop imaginative approaches. Metal-catalyzed multicomponent reactions (MCRs) offer optimal molecular diversity, high atomic efficiency, and energy savings in a single reaction step. These versatile protocols are often used to synthesize numerous natural compounds, heterocyclic molecules, and medications. Thus far, the majority of metal-catalyzed MCRs under investigation are based on metal catalysts such as copper and palladium; however, current research is focused on developing novel, environmentally friendly catalytic systems. In this regard, this study demonstrates the effectiveness of metal catalysts in MCRs. The aim of this study is to provide an overview of metal catalysts for safe application in MCRs.

Non-Palladium-Catalyzed Oxidative Coupling Reactions Using Hypervalent Iodine Reagents

Transition metal-catalyzed direct oxidative coupling reactions via C–H bond activation have emerged as a straightforward strategy for the construction of complex molecules in organic synthesis. The direct transformation of C–H bonds into carbon–carbon and carbon–heteroatom bonds renders the requirement of prefunctionalization of starting materials and, therefore, represents a more efficient alternative to the traditional cross-coupling reactions. The key to the unprecedented progress made in this area has been the identification of an appropriate oxidant that facilitates oxidation and provides heteroatom ligands at the metal center. In this context, hypervalent iodine compounds have evolved as mainstream reagents particularly because of their excellent oxidizing nature, high electrophilicity, and versatile reactivity. They are environmentally benign reagents, stable, non-toxic, and relatively cheaper than inorganic oxidants. For many years, palladium catalysis has dominated these oxidative coupling reactions, but eventually, other transition metal catalysts such as gold, copper, platinum, iron, etc. were found to be promising alternate catalysts for facilitating such reactions. This review article critically summarizes the recent developments in non-palladium-catalyzed oxidative coupling reactions mediated by hypervalent iodine (III) reagents with significant emphasis on understanding the mechanistic aspects in detail.

Asymmetric Direct/Stepwise Dearomatization Reactions Involving Hypervalent Iodine Reagents

A remarkable growth in hypervalent iodine-mediated oxidative transformations as stoichiometric reagents as well as catalysts has been well-documented due to their excellent properties, such as mildness, easy handling, high selectivity, environmentally friendly nature, and high stability. This review aims at highlighting the asymmetric oxidative dearomatization reactions involving hypervalent iodine compounds. The present article summarizes asymmetric intra- and intermolecular dearomatization reactions using chiral hypervalent iodine reagents/catalysts as well as hypervalent iodine-mediated dearomatization reactions followed by desymmetrization.

Triflimide-Promoted Nucleophilic C-Arylation of Halopurines to Access N7-Substituted Purine Biaryls

Functionalized nucleobases are utilized in a wide range of fields; therefore, the development of new synthesis methods is essential for their continued application. With respect to the C⁶-arylation of halopurines, which possess a substituent at the N⁷-position, only a small number of successful cases have been reported, which is predominately a result of large steric hinderance effects. Herein, we report efficient and metal-free C⁶-arylations and S_NAr reactions of N⁷-substituted chloropurines in aromatic and heteroatom nucleophiles promoted by triflimide (Tf₂NH) in fluoroalcohol.

Practical Synthesis of 2-Iodosobenzoic Acid (IBA) without Contamination by Hazardous 2-Iodoxybenzoic Acid (IBX) under Mild Conditions

We report a convenient and practical method for the preparation of nonexplosive cyclic hypervalent iodine(III) oxidants as efficient organocatalysts and reagents for various reactions using Oxone® in aqueous solution under mild conditions at room temperature. The thus obtained 2-iodosobenzoic acids (IBAs) could be used as precursors of other cyclic organoiodine(III) derivatives by the solvolytic derivatization of the hydroxy group under mild conditions of 80 °C or lower temperature. These sequential procedures are highly reliable to selectively afford cyclic hypervalent iodine compounds in excellent yields without contamination by hazardous pentavalent iodine(III) compound.

Heteroaryliodonium(III) Salts as Highly Reactive Electrophiles

In recent years, the chemistry of heteroaryliodonium(III) salts has undergone significant developments. Heteroaryliodonium(III) salts have been found to be useful synthetic tools for the transfer of heteroaryl groups under metal-catalyzed and metal-free conditions for the preparation of functionalized heteroarene-containing compounds. Synthetic transformations mediated by these heteroaryliodonium(III) salts are classified into two categories: (1) reactions utilizing the high reactivity of the hypervalent iodine(III) species, and (2) reactions based on unique and new reactivities not observed in other types of conventional diaryliodonium salts. The latter feature is of particular interest and so has been intensively investigated in recent decades. This mini-review therefore aims to summarize the recent synthetic applications of heteroaryliodonium(III) salts as highly reactive electrophiles.

Synthesis of Uracil-Iodonium(III) Salts for Practical Utilization as Nucleobase Synthetic Modules

Iodonium(III) salts bearing uracil moieties have recently appeared in the literature, but their structural scope and utilization are limited because of their hygroscopic characteristics. In this study, we describe our detailed investigations for synthesizing a series of uracil iodonium(III) salts derived with various structural motifs and counterions. These new compounds have been utilized as attractive synthetic modules in constructing functionalized nucleobase and nucleosides.

Planar chiral [2.2]paracyclophane-based phosphine–phenols: use in enantioselective [3 + 2] annulations of allenoates and N-tosylimines

Planar chiral [2.2]paracyclophane-based phosphine–phenols efficiently catalyze the [3 + 2] annulation of N-tosylimines and allenoate.

Mechanism of the anti-obesity effects induced by a novel melanin-concentrating hormone 1-receptor antagonist in mice

BACKGROUND AND PURPOSE

Melanin-concentrating hormone (MCH) is an orexigenic neuropeptide expressed in the lateral hypothalamus that is involved in feeding and body weight regulation. Intracerebroventricular infusion of a peptidic MCH1 receptor antagonist ameliorated obesity in murine models. Recently, small molecule MCH1 receptor antagonists have been developed and characterized for the treatment of obesity. However, little is known of the mechanism of the anti-obesity effects of MCH1 receptor antagonists.

EXPERIMENTAL APPROACH

To examine the mechanisms of action of the anti-obesity effect of MCH1 receptor antagonists more precisely, we conducted a pair-feeding study in mice with diet-induced obesity (DIO), chronically treated with an orally active and highly selective MCH1 receptor antagonist and examined changes in mRNA expression levels in liver, brown and white adipose tissues. We also assessed the acute effects of the MCH1 receptor antagonist in energy expenditure under thermoneutral conditions.

KEY RESULTS

Treatment with the MCH1 receptor antagonist at 30 mg.kg(-1) for 1 month moderately suppressed feeding and significantly reduced body weight by 24%. In contrast, pair-feeding resulted in a smaller weight reduction of 10%. Treatment with the MCH1 receptor antagonist resulted in a higher body temperature compared with the pair-fed group. TaqMan and calorimetry data suggested that the MCH1 receptor antagonist also stimulated thermogenesis.

CONCLUSIONS AND IMPLICATIONS

Our results indicate that an MCH1 receptor antagonist caused anti-obesity effects im mice by acting on both energy intake and energy expenditure.

Versatile direct dehydrative approach for diaryliodonium(III) salts in fluoroalcohol media

We have found that the use of fluoroalcohol media greatly enhanced the efficiency and scope of the direct dehydrative condensation of arenes and hypervalent iodine(III) compounds; the present clean method has a broad range of applicability as well as unique selectivity in the aromatic substrates, and is highly efficient even in polymer functionalization.

Direct Lactone Formation by Using Hypervalent Iodine(III) Reagents with KBr via Selective C−H Abstraction Protocol

We have developed a new and reliable method for the direct construction of biologically important aryl lactones and phthalides from carboxylic and benzoic acids, using a combination of hypervalent iodine(III) reagents with KBr.

First hypervalent iodine(iii)-catalyzed C–N bond forming reaction: catalytic spirocyclization of amides to N-fused spirolactams

A protic solvent, 2,2,2-trifluoroethanol (CF(3)CH(2)OH), was successfully introduced into hypervalent iodine(III)-involved catalytic cycles as an effective solvent, and the first iodoarene-catalyzed intramolecular carbon-nitrogen bond forming reaction was achieved under strong acid-free and mild conditions.

Direct Cyanation of Heteroaromatic Compounds Mediated by Hypervalent Iodine(III) Reagents: In Situ Generation of PhI(III)−CN Species and Their Cyano Transfer

Hypervalent iodine(III) reagents mediate the direct cyanating reaction of a wide range of electron-rich heteroaromatic compounds such as pyrroles 1, thiophenes 3, and indoles 5 under mild conditions (ambient temperature), without the need for any prefunctionalization. Commercially available trimethylsilylcyanide is usable as a stable and effective cyanide source, and the reaction proceeds in a homogeneous system. The N-substituent of pyrroles is crucial to avoid the undesired oxidative bipyrrole coupling process, and thus a cyano group was introduced selectively at the 2-position of N-tosylpyrroles 1 in good yields using the combination of phenyliodine bis(trifluoroacetate) (PIFA), TMSCN, and BF3.Et2O at room temperature. In the reaction mechanism, cation radical intermediates of heteroaromatic compounds are involved as a result of single electron oxidation, and the key to successful transformations seems to depend on the oxidation potential of the substrates used. Thus, the reaction was also successfully extended to other heteroaromatic compounds having oxidation potentials similar to that of N-tosylpyrroles such as thiophenes 3 and indoles 5. However, regioisomeric mixtures of the products derived from the reaction at the 2- and 3-positions were obtained in the case of N-tosylindole 5a. Further investigation performed in our laboratory provided insights into the real active iodine(III) species during the reaction; the reaction is induced by an active hypervalent iodine(III) species having a cyano ligand in situ generated by ligand exchange reaction at the iodine(III) center between trifluoroacetoxy group in PIFA and TMSCN, and effective cyanide introduction into heteroaromatic compounds is achieved by means of the high cyano transfer ability of the hypervalent iodine(III)-cyano intermediates. In fact, the reaction of N-tosylpyrrole 1a with a hypervalent iodine(III)-cyano compound (e.g., (dicyano)iodobenzene 8), in the absence of TMSCN, took place to afford the 2-cyanated product 2a in good yield, and an effective preparation of the intermediates is of importance for successful transformation. 1,3,5,7-Tetrakis[4-{bis(trifluoroacetoxy)-iodo}phenyl]adamantane 12, a recyclable hypervalent iodine(III) reagent, was also comparable in the cyanating reactions as a valuable alternative to PIFA, affording a high yield of the heteroaromatic cyanide by facilitating isolation of the cyanated products with a simple workup. Accordingly, after preparing the active hypervalent iodine(III)-CN species by premixing of a recyclable reagent 12, TMSCN, and BF3.Et2O for 30 min in dichloromethane, reaction of a variety of pyrroles 1 and thiophenes 3 provided the desired cyanated products 2 and 4 in high yields. The iodine compound 13, recovered by filtration after replacement of the reaction solvent to MeOH, could be reused without any loss of activity (the oxidant 12 can be obtained nearly quantitatively by reoxidation of 13 using m-CPBA).

A Facile and Clean Direct Cyanation of Heteroaromatic Compounds Using a Recyclable Hypervalent Iodine(III) Reagent

The facile and clean direct cyanating reaction of pyrroles and thiophenes has been achieved using a recyclable hypervalent iodine(III) reagent 1b by a simple solid-liquid separation of the products and the reagent.

[The risk of colorectal adenomatous polyp in relation to serum total cholesterol levels in Japanese men classified by age group]

In order to investigate the relationship between the risk of colorectal cancer and serum total cholesterol (TC) levels, we studied the relationship between the risk of colorectal adenomatous polyp and high TC levels in Japanese men aged from 40 to 59 at a manufacturing company. We first diagnosed 283 subjects as having adenomatous polyp (AD) or normal (C), identified by means of an immunological fecal occult blood detection test and total colonofiberscopic examination (TCF), and then selected 94 subjects after excluding the patients with diseases possibly influencing TC. We classified the subjects into two age groups (40-49 and 50-59) and conducted a statistical analysis of AD and C groups by means of a two tailed t-test. The mean values for TC (DTC), which had been obtained within 3 months before TCF, were significantly different (p < 0.001 95% CI 15.79-48.49) for those in their 40s, but were not different for those in their 50s. In order to check the stability of the data, we analyzed the mean values for DTC and BTC, which had been obtained within 15 months. The results showed the same trend for those in their 40s (p = 0.001 95% CI 10.76-40.87). The mean DTC and BTC values were again not significantly different for those in their 50s. We further divided the subjects into the lower (-181 mg/dl) and higher (209 mg/dl-) DTC values and conducted further statistical analysis with Fisher's exact test. The results were significant in the 40-49 age group (p = 0.004), in the odds ratio (13.75 95% CI 2.32-81.49), but showed no significant difference in the 50-59 age group. The mean LDL-cholesterol values within 3 months before TCF were significantly different in the 40-49 age group (p < 0.001 95% CI 15.22-47.70) and were not different in the 50-59 age group. There was no statistical difference in the mean values for HDL-cholesterol, triglyceride and body mass index in either age group. From these results, it can be concluded that the risk of colorectal adenomatous polyp was associated with a higher serum total cholesterol level in the 40s, and seemed to indicate a close relationship with the risk of colorectal cancer.

In vivo metabolism of a new anticancer agent, 6-N-formylamino-12, 13-dihydro-1,11-dihydroxy-13-(beta-D-glucopyranosil)5H-indolo [2,3-a]pyrrolo [3,4-c]carbazole-5,7(6H)-dione (NB-506) in rats and dogs: pharmacokinetics, isolation, identification, and quantification of metabolites

6-N-formylamino-12,13-dihydro-1, 11-dihydroxy-13-(beta-D-glucopyranosil)5H-indolo [2,3-a]pyrrolo [3, 4-c]carbazole-5,7(6H)-dione (NB-506), a potent inhibitor of DNA topoisomerase I, is currently under development for the treatment of cancer. We investigated the pharmacokinetics of NB-506 after i.v. administration in rats and dogs. The plasma concentration of NB-506 decreased biexponentially in rats and dogs with terminal half-lives of approximately 2 h. The area under the curve increased nonlinearly with increasing dose in rats. In contrast, there was a linear relationship between the area under the curve and the dose in dogs. In rats, the plasma clearance decreased with increasing dose up to 187.5 mg/m2 but remained virtually unchanged at the highest dose. The Vdss of NB-506 in rats and dogs was much greater than the plasma volume, indicating that NB-506 is highly distributed to tissue from plasma in these animals. There were marked species differences in the plasma concentrations of ED-501 after i.v. administration of NB-506 to rats and dogs. To better understand the mechanisms of nonlinear pharmacokinetics in rats, in vivo metabolites were determined. After i.v. administration of [14C]NB-506 to rats, two unknown metabolites (RBM-1 and RBM-2), deformyl metabolite (ED-501), and unchanged drug (NB-506) were identified. Mass and NMR spectra analysis revealed that RBM-1 is an 11-O-glucuronide of NB-506 (ED-594) and that RBM-2 is an 11-O-glucuronide of ED-501 (ED-595). In this study, the pharmacokinetics of NB-506 was demonstrated to be nonlinear in rats, probably because of saturation of the enzyme systems catalyzing the deformylation and glucuronidation of NB-506 in rats.

In vitro metabolism of a new anticancer agent, 6-N-formylamino-12, 13-dihydro-1,11-dihydroxy-13-(beta-D-glucopyranosil)5H-indolo+ ++[2,3-a]pyrrolo[3,4-c]carbazole-5,7(6H)-dione (NB-506), in mice, rats, dogs, and humans

The metabolism of 6-N-formylamino-12,13-dihydro-1, 11-dihydroxy-13-(beta-D-glucopyranosil)5H-indolo [2,3-a]pyrrolo [3, 4-c]carbazole-5,7(6H)-dione (NB-506), a potent inhibitor of DNA topoisomerase I, was characterized in mice, rats, dogs, and humans in vitro. NB-506 was deformylated to ED-501 in mouse and rat plasma with enzyme activity of 140 and 116 pmol/min/mg protein, respectively. The enzyme activity in dog and human plasma was found to be less than 1.7 pmol/min/mg protein. In liver S9 and small intestine S9 samples from mice and rats, activity of the enzyme was very low. Also, there was no activity in the liver or small intestine of dogs and humans. The enzyme involved in the conversion of NB-506 to ED-501 in rat plasma is a rodent-specific serine enzyme with a molecular mass of 138KDa. The Vmax and Km values were 6.3 nmol/min/ml plasma and 54 microM at an optimum pH of 7.4, respectively. Although NB-506 was converted to ED-551 in dog and human plasma in vitro, no conversion was observed in mouse and rat plasma. In human plasma this conversion was not affected by heat treatment (100 degreesC for 1 min), but was inhibited completely by 50 mM EDTA, indicating that the reaction is a chemical reaction catalyzed by metal ions. Although NB-506 was not metabolized by cytochrome P-450 isozymes in liver, this drug was glucuronized in mice, rats, and humans, but not in dogs. These results suggest that a species difference in the metabolism of NB-506 occurred in the liver as well as in plasma. There appeared to be species differences in the metabolism of NB-506 in vitro, correlating well with the species-dependent pharmacokinetics of this drug in vivo.

Simultaneous determination of a new anticancer agent (NB-506) and its active metabolite in human plasma and urine by high-performance liquid chromatography with ultraviolet detection

A high-performance liquid chromatographic method with ultraviolet detection has been developed to quantify NB-506 and its active metabolite in human plasma and urine. This method is based on solid-phase extraction, thereby allowing the simultaneous measurement of the drug and metabolite with the limit of quantification of 0.01 microgram/ml in plasma and 0.1 microgram/ml in urine. Standard curves for the compounds were linear in the concentration ranges investigated. The range for the drug in plasma was 0.01-2.5 micrograms/ml, and for the metabolite 0.01-1 microgram/ml. In urine, the range for both compounds was 0.1-10 micrograms/ml. The method was validated and applied to the assay of plasma and urinary samples from phase I studies.

Pharmacokinetic and pharmacodynamic analysis of a novel leukotriene biosynthesis inhibitor, MK-0591, in healthy volunteers

1. The pharmacokinetic and pharmacodynamic properties of a novel 2-indolealkanoic acid derivative (MK-0591), a potent inhibitor of leukotriene biosynthesis, were investigated in healthy male Japanese volunteers. Single oral doses of 50, 125, 250 and 500 mg and multiple oral doses of 125 mg twice daily for 9.5 days and 250 mg once daily for 10 days were administered. 2. After the single-dose administration following overnight fasting, Cmax and AUC of MK-0591 in plasma increased in a dose-dependent manner, while elimination half-life remained constant (11.2-13.2 h) irrespective of dose. Food intake decreased Cmax and AUC by 71% and 68%, respectively, at a dose of 250 mg. With respect to multiple-dose administration before meals, there were no significant differences in the pharmacokinetic parameters between the first and last days, indicating a lack of significant accumulation of MK-0591 in plasma. Urinary recovery as the unchanged form was negligible throughout the study. 3. Ionophore-stimulated production of leukotriene B4 (LTB4) in blood ex vivo was inhibited significantly from 1 h until 12 to 48 h after single-dose administration as compared with predose value. In parallel, the urinary excretion of endogenous leukotriene E4 (LTE4) was significantly decreased from 4 to 8 h until 48 to 72 h after drug administration. Reduction of ionophore-stimulated LTB4 biosynthesis and urinary excretion of LTE4 following single administration of MK-0591 was statistically significant as compared with placebo group, and the duration of inhibition of LTB4 biosynthesis was dose-related.(ABSTRACT TRUNCATED AT 250 WORDS)

Diagnostic significance of serum angiotensin-converting enzyme activity in biochemical tests with special reference of chronic liver diseases

To assess the degree of the differential ability of serum angiotensin-converting enzyme (ACE) activity as compared with 13 conventional biochemical tests, we studied 76 healthy subjects and 107 patients with chronic liver diseases. It was found that the mean values of serum ACE activity were significantly different between the healthy group and groups with liver disease. According to discriminant function analysis, the diagnostic accuracy reached 82.2% in 14 tests. In order to analyze the extent of contribution of each test to the entire diagnostic accuracy, we made an indicator of the relative decrease rate expressed as a percentage, which is 100-100 x (13-test diagnostic accuracy less one test/14-test diagnostic accuracy). The relative decrease rate of serum ACE activity was 11.4%, the largest in value. In conclusion, serum ACE activity may be one of the best discriminators to characterize chronic liver disease.

Absorption of a novel prodrug of L-dopa, L-3-(3-hydroxy-4-pivaloyloxyphenyl)alanine (NB-355). In vitro and in situ studies

Absorption mechanism and absorption site of a prodrug of L-DOPA, L-3-(3-hydroxy-4-pivaloyloxyphenyl)alanine (NB-355, 1) was investigated using rats. Prodrug 1 (0.5 mM) was taken up by intestinal tissue segments time-dependently in vitro at pH 6.0. However, the rate of uptake was less than that of L-dopa. Inhibitors of the amino acid active transport system (L-Phe, dinitrophenol, ouabain) had no effect on the uptake of prodrug 1. In the intestinal tissue segments, prodrug 1 was extensively hydrolyzed by diisopropylfluorophosphate-sensitive esterase(s). To characterize the absorption site, gastrointestinal tracts were ligated to make acute loops in situ and prodrug 1 or L-dopa was injected into the loops. L-dopa disappeared rapidly from the lumen of the jejunum. In contrast, prodrug 1 disappeared rapidly from the ileum rather than the duodenum or jejunum. From these results, it was suggested that prodrug 1 was slowly absorbed primarily from the lower small intestine.

Quantification of L-3-(3-hydroxy-4-pivaloyloxyphenyl)alanine (NB-355) by high-performance liquid chromatography using o-phthalaldehyde/N-acetyl-L-cysteine derivatization

A new and rapid high-performance liquid chromatographic assay has been developed for the determination of L-3-(3-hydroxy-4-pivaloyloxyphenyl)alanine (NB-355,I), a novel prodrug of L-DOPA. The method involves precolumn derivatization of the drug in biological samples with o-phthalaldehyde (OPA) and N-acetyl-L-cysteine (NAC) in a triethanolamine buffer (pH 8.0), giving a fluorescent compound that is stable for 2 h at 4 degrees C. Use of an internal standard improved the assay in accuracy and reliability. A programmable injector allowed automatic derivatization of large numbers of samples. Chromatographic separation was performed on a reversed-phase column (Capcell Pak C18) in which the silica gel was coated with silicone polymer. The peaks corresponding to compound I and the internal standard were eluted within 16 min with a mobile phase of acetonitrile-phosphate buffer (pH 7.1). The reliable limit of quantification was 0.5 pmol per injection (0.05 micrograms equivalents of L-DOPA per ml in plasma). The method was successfully applied for the measurements of dog plasma concentrations after oral dosing of compound I.

Why are cadaveric renal transplants so hard to find in Japan? An analysis of economic and attitudinal aspects

In view of the fact that in Japan treatment of end-stage renal disease depends disproportionately heavily on hemodialysis and almost negligible on transplants from cadaveric donors (hemodialysis 44.4/100,000; renal transplants 0.31/100,000 per year; cadaveric renal transplants 0.11/100,000 per year (1983 data)), we analysed the cost-effectiveness of hemodialysis and renal transplantation, predicted economic gains under expected changes in variables and described attitudes of the Japanese hampering cadaveric renal transplantation. Adjusted life expectancy of transplant recipients (live and cadaveric combined) under the current technical conditions is longer than that of those on hemodialysis (18.3 vs. 14.7 years) and the cost per year for maintaining the transplant is approximately one third of hemodialysis ($12,000 vs $32,000). If the proportion of cadaveric transplant recipients would increase to the levels of the USA (hemodialysis 30.8/100,000; transplants 2.6/100,000 per year; cadaveric transplants 1.9/100,000 per year (1983 data)) along with improvement in graft survival rate, the life expectancy for transplant recipients in Japan could increase by 2 years, thus reducing the annual cost even further. The current number of patients starting hemodialysis (11,500 cases per year) coupled with their life expectancy predicts the number of patients on hemodialysis to reach equilibrium at around 174,000 in a decade (Japanese population 110 million). Based on current price, their annual cost will be about 5.3 billion dollars. Medical expenditure of this magnitude for such a small fraction of people is expected to become an increasingly strong economic incentive for cadaveric renal transplantation. A review of studies on Japanese attitudes toward cadaveric renal transplantation in both urban and rural areas shows that approximately 60% are in favor of donating their kidney after death, though with the majority of cases the donation is contingent upon agreement of their family. It was suggested that the paucity of cadaveric kidney supply stems mainly from the custom of the Japanese to make decisions by consensus. It was also reported that more than 80% of physicians supported the donation of cadaveric grafts while this rate fell to 40% in case of brain death. As the first heart transplantation was carried out in 1968 under both medically and ethically dubious circumstances, distrust toward the diagnosis of brain death appears to be still quite strong. (Not a single heart transplantation has been attempted in Japan in the past 18 years).(ABSTRACT TRUNCATED AT 400 WORDS)

Evaluation of three cervical cancer detection programs in Japan with special reference to cost-benefit analysis

Three screening programs for early cervical cancer currently in use in Japan were evaluated according to the following criteria: (1) economic effectiveness; (2) screening efficiency; and (3) access to medical care. The mobile program has the highest benefit-cost ratio (BCR, 1.20) and is hence most cost-effective; its detection rate, rescreening rate, and early cancer detection rate (proportion of Stage-O patients to all patients with cancer) are moderately high (0.09%, 2.07%, 55%, respectively). It is obviously suited to rural areas, especially where residents have a positive attitude toward local health services. The detection center program is less cost-effective than the mobile program (BCR, 0.83) but diagnostically the most effective with highest detection, rescreening, and early cancer detection rate (0.15%, 5.08%, 61%, respectively). It is suitable to large cities (population over 1 million) with efficient public transportation. The private physician program is economically and in terms of screening efficiency least effective of the three; its BCR being 0.40 and detection, rescreening, and early cancer detection rate being the lowest (0.08%, 0.29%, 33%, respectively). However, the private physician program is increasingly employed, presumably because of easy access to medical care, better rapport between the patient and physician, and, in addition, successful lobbying by private physicians.