Quantitative analysis of DNA-porphyrin interactions

The binding of manganese(III)-tetra(4-N-methylpyridyl)porphyrin (MnTMpyP) with synthetic poly(dA-dT)2, poly(dI-dC)2, and poly(dG-dC)2 DNAs as well as calf thymus (CT) DNA has been quantitatively studied in detail using induced CD (circular dichroism) spectroscopy in the Soret absorption band. The CD spectra, which changed greatly depending on the porphyrin to DNA base-pair molar ratio (r), were normalized with respect to DNA concentration and deconvoluted. Three independent component binding modes (named mode 1, 2, and 3 in the order of increasing r values) were identified, which successfully simulated the observed CD spectra with negligibly small residuals for a wide range of r values. In the case of poly(dA-dT)2, poly (dI-dC)2, and CT DNA, all the three modes appeared, whereas in the case of poly(dG-dC)2 DNA, only modes 1 and 3 appeared in the r range studied. The r dependence of each binding mode, i.e., its relative affinity toward DNA, has been revealed by this analysis. Mode 1, which appeared as a single binding mode at very low r values (r < or = ca. 0.05), was inhibited by the addition of methyl green, a drug that preferentially binds to the major groove of poly (dA-dT)2 DNA. Berenil, a known minor groove binder to poly(dA-dT)2 or poly(dI-dC)2 DNA, inhibited modes 2 and 3. From these inhibition experiments as well as comparison of the component spectra for DNAs of different sequence, a binding site on DNA was proposed for each component binding mode. The number of DNA base pairs covered by a single molecule of porphyrin was estimated.

A case of primary extragonadal seminoma arising in the perineum

We report the first case of primary extragonadal seminoma arising in the perineum. A 34-year-old-man presented with a 2-cm painless mass in the perineum. He underwent surgical resection, and histology showed poorly differentiated adenocarcinoma. Three months later, local recurrence occurred. Whole evaluation including ultrasound and MRI of the testes were normal, so he underwent surgical wide excision, and pathology showed the tumor was pure seminoma. He received two courses of bleomycin, etoposide and cisplatin (BEP) therapy, and there has been no evidence of recurrence for 1 month.

Gelation of Xyloglucan by Addition of Epigallocatechin Gallate as Studied by Rheology and Differential Scanning Calorimetry

Interaction of tamarind seed xyloglucan (TSX) and epigallocatechin gallate (EGCG) was investigated. TSX alone showed the rheological behaviors of dilute and semidilute solution types in the temperature range from 10 to 50 degrees C and the concentration range from 1 to 10%. Addition of a small amount of EGCG changed the rheological properties of TSX solutions to induce a thermoreversible gelation. The sol-gel transition was detected as a crossover of the storage and loss shear moduli at a certain temperature in thermal scanning rheological measurements and an endo- and exo- thermic peaks in curves obtained by differential scanning calorimetry on heating and cooling. High storage modulus of the gels at all experimental frequencies also indicated the formation of a network structure. Increase in the gel strength and the enthalpy of the transition with increasing EGCG concentration at fixed TSX concentration suggested that EGCG was directly involved in the network formation through association with TSX. The TSX gel was obtained by addition of appropriate amount of EGCG. Addition of an excessive amount of EGCG induced precipitation.

Long term effects of exposure to automobile exhaust on the pulmonary function of female adults in Tokyo, Japan

AIMS

To investigate the chronic effects of air pollution caused mainly by automobiles in healthy adult females.

METHODS

Respiratory symptoms were investigated in 5682 adult females who had lived in the Tokyo metropolitan area for three years or more in 1987; 733 of them were subjected to pulmonary function tests over eight years from 1987 to 1994. The subjects were divided into three groups by the level of air pollution they were exposed to during the study period. The concentrations of nitrogen dioxide and suspended particulate matter were the highest in group 1, and the lowest in group 3.

RESULTS

The prevalence rates of respiratory symptoms in group 1 were higher than those in groups 2 and 3, except for wheezing. Multiple logistic regression analysis showed significant differences in persistent phlegm and breathlessness. The subjects selected for the analysis of pulmonary function were 94, 210, and 102 females in groups 1, 2, and 3, respectively. The annual mean change of FEV(1) in group 1 was the largest (-0.020 l/y), followed by that in group 2 (-0.015 l/y), and that in group 3 (-0.009 l/y). Testing for trends showed a significant larger decrease of FEV(1) with the increase in the level of air pollution.

CONCLUSIONS

The subjects living in areas with high levels of air pollution showed higher prevalence rates of respiratory symptoms and a larger decrease of FEV(1) compared with those living in areas with low levels of air pollution. Since the traffic density is larger in areas with high air pollution, the differences among the groups may reflect the effect of air pollution attributable to particulate matter found in automobile exhaust.

Relationship between oocyte apoptosis and ovarian tumours induced by high and low LET radiations in mice

PURPOSE

To investigate the biological effectiveness of neutrons at the energy below 1 MeV on apoptosis and carcinogenesis in the mouse ovary.

MATERIALS AND METHODS

Female mice were exposed to 1.0 Gy monoenergetic neutrons (0.317, 0.525 and 1.026 MeV), (252)Cf fission neutron (2.13 MeV) or (137)Cs gamma-rays at 7 days of age. Apoptosis of the oocyte and pregranulosa cells, and ovarian carcinogenesis were compared between the radiations. The efficiency of gamma-rays for granulosa cell tumorigenesis was tested by transplantation of the irradiated ovaries into non-irradiated mice.

RESULTS

The cumulative apoptotic index of oocytes was 77.9%, 65.6% and 41.6% for the 0.525 MeV neutron, 2.13 MeV neutron and gamma-rays, respectively. Follicles with apoptotic pregranulosa cells were 53.0%, 18.3% and 22.8% of cumulative index for the three groups. Tubular adenomas developed in the groups of monoenergetic neutrons (26.1%) and gamma-ray (35.5%), whereas granulosa cell tumours developed only in the gamma-ray groups (3.2% for 1.0 Gy and 15.6% for 3.0 Gy). Partial-body irradiation with 3 Gy gamma-rays to the ovaries induced granulosa cell tumours with an incidence of 27.3%.

CONCLUSION

Effectiveness of neutrons to cause apoptosis was higher for 0.525 MeV than for 2.13 MeV. The pregranulosa cell apoptosis occurred in an oocyte-prone manner. The higher effectiveness of neutrons than gamma-rays to induce oocyte and pregranulosa cell apoptosis correlates with the inhibition of granulosa cell tumour development.

Difference in coronary blood flow dynamics between patients with hypertension and those with hypertrophic cardiomyopathy

We studied twelve patients with hypertensive left ventricular hypertrophy (LVH), 10 patients with hypertrophic cardiomyopathy (HCM) and 10 control subjects to examine the differences in coronary blood flow (CBF) dynamics between patients with hypertensive LVH and those with HCM. All subjects had normal coronary arteriograms. Measurements of CBF using Doppler Flo-Wire were performed at rest, and after infusions of acetylcholine and papaverine. The baseline CBF was significantly increased in both hypertensive LVH patients and HCM patients compared to that noted in control subjects (64.1+/-36.9, 80.0+/-38.1, 32.3+/-8.0 ml/min, respectively, p<0.01). Coronary flow reserve and endothelium-dependent vasodilatation were significantly lower in hypertensive LVH patients and HCM patients than in control subjects, but there was no significant difference between the hypertensive LVH and HCM patients themselves. In contrast, the diastolic/systolic velocity ratio at baseline was significantly lower in hypertensive LVH patients than in HCM patients (1.53+/-0.40, 6.31+/-7.50, p<0.05). Although CBF and coronary flow reserve correlated positively and negatively, respectively, with left ventricular mass index (r=0.51, -0.59, respectively), the diastolic/systolic velocity ratio at baseline did not show a significant correlation to left ventricular mass index. In conclusion, the diastolic/systolic velocity ratio differed between hypertensive LVH and HCM patients, independent of left ventricular mass. These results suggest that the difference of phasic pattern of CBF may be essential for coronary circulation in patients with hypertensive LVH and in those with HCM.

Induction of donor-specific tolerance to islet allografts in nonhuman primates

Pancreatic tissue grafting is by far the most physiological therapeutic solution to the insulin deficiency of diabetes. Recent clinical trials have indicated somewhat successful use of nonsteroidal immunosuppressive regimens and a successful nonhuman primate trial using CD154 for costimulation blockade was reported. However, these protocols need to be replaced with safe and efficacious ones in which long-term allotolerance would make these treatments routine in a clinical setting. With the specific objective of testing whether peripheral infusions of stem cells or stem cell fractions in conjunction with islet allografting would induce allograft tolerance, we have established a macaque diabetic model. The macaques were rendered diabetic by streptozotocin and required daily doses of insulin to maintain lower blood glucose levels. The diabetic macaques then received islets and stem cells from unrelated and MHC-mismatched donors without any immunosuppression. In our initial analysis, 5 of 7 macaques that received stem cell infusions at the time of islet allografting have shown allograft survival longer than the group of macaques that received islets without the stem cell infusion. One of these five macaques has been normoglycemic for 10 months, with no exogenous insulin. This macaque received stem cell population enriched for CD34+ cells with depletion of CD18 cells, which have shown low or no allostimulatory potential in mixed lymphocyte cultures. Increased levels in insulin and C-peptide levels were shown in the macaques after islet transplantation.

Induction of islet allotolerance in nonhuman primates

Recent clinical trials have pioneered the successful use of a nonsteroidal immunosuppressive regimen and established a basis for application in a routine clinical setting. In this study, a single islet transplant was not sufficient to regulate blood glucose levels, and a second transplant became necessary. A similar observation was made in our macaque islet transplant study, where animals after the second transplantation have shown trends towards normoglycemia in the presence of mycophenolate mofetil. All five animals that received the second transplant have shown an initial rise in C peptide levels, which rapidly decreased as we tapered the MMF dose from 20 mg/kg BID to 5 mg/kg SID. Two animals of the five that were preconditioned with MMF one week prior to transplantation have shown significantly higher C peptide levels. We believe that it is very important to understand the relationship between the first graft failure and subsequent islet allograft success. Since graft success did not correlate with number of transplanted islets, the correction of blood glucose levels toward normoglycemia after the second transplantation suggests a mechanism by which the allotolerance to second transplant is facilitated by the first islet transplantation. These initial observations suggest approaches to "tolerize" the recipient to accept the second-transplant islets (a) through preconditioning the animal to improve the rate of success for the first transplant or (b) through tolerization to islets in the first transplant to facilitate better engraftment of the second-transplant islets.

Changes in serotonin dynamics in the gastrointestinal tract of colon-26 tumour-bearing mice: effects of cisplatin treatment

Severe nausea and vomiting are common side effects of anti-cancer chemotherapy. 5-HT3 receptor antagonists have been used for the treatment of these gastrointestinal symptoms. The purpose of this study was to examine whether specific changes in serotonin dynamics occurred in the gastrointestinal tract in mice in which Colon-26 adenocarcinoma cells were injected s.c., especially after treatment with cisplatin. The serotonin content of the small intestine of mice inoculated s.c. with Colon-26 adenocarcinoma increased significantly 2 weeks after the inoculation of the tumor cells; this was associated with an increase in tryptophan hydroxylase activity and the number of enterochromaffin cells as compared with control mice. Intravenous injection of cisplatin significantly reduced the serotonin content in the small intestine of Colon-26 tumour-bearing mice but not in control mice. The spontaneous release of serotonin from isolated intestine was not different between Colon-26 tumour-bearing and control mice; however, pretreatment of mice with cisplatin induced two fold increases in serotonin release from duodenum, jejunum and ileum in Colon-26 tumour-bearing mice but not in control mice. These results indicate that a region-specific increase in the number of enterochromaffin cells is observed in the intestine of Colon-26 tumour-bearing mice, associated with an increase in the serotonin content and tryptophan hydroxylase activity. Cisplatin treatment induced the release of serotonin from affected enterochromaffin cells in the gastrointestinal tract, which may be related to the occurrence of nausea in clinical use.

Extensive cell death in thymocytes in colon 26-induced cachectic mice

Extensive atrophy has been reported to occur in the thymus in a cancer-burden state but the mechanisms of this atrophy have not been fully elucidated. We investigated changes in the thymus in tumour-bearing mice inoculated with two subclones of the murine colon 26 adenocarcinoma cell line: clone 5 (non-cachectic) and clone 20 (cachectic). In clone 20 mice, body weights and thymocyte numbers decreased significantly compared with controls. Flow cytometric analysis of the thymocytes demonstrated that the frequency of single positive cells (CD4+ CD8- and CD4- CD8+) was significantly increased and that of double positive cells (CD4+ CD8+) was significantly decreased in clone 20 mice and, to a lesser extent, in clone 5 mice compared with controls. Serum levels of interleukin 6 and granulocyte-macrophage colony-stimulating factor (GM-CSF) were significantly elevated. These results suggested that thymocyte apoptosis was accelerated in the cancer-cachectic state, and increased GM-CSF might be partly responsible for thymic atrophy.

Effect of thermosensitive liposomal doxorubicin with hyperthermia on primary tumor and lung metastases in hamster osteosarcoma

We evaluated the effect of intravenous thermosensitive liposomal doxorubicin (TL-DOX) together with local hyperthermia on primary tumors in highly metastatic hamster osteosarcoma. This combination resulted in higher DOX concentrations in plasma, primary tumors and lungs than standard DOX under the same conditions. Tumor growth and lung metastasis were also inhibited more by TL-DOX and hyperthermia than by hyperthermia alone, DOX with or without hyperthermia, and TL-DOX without hyperthermia. In addition, gains in hamster body weight were not suppressed. These results suggest that the combination of TL-DOX and hyperthermia can control primary tumors and suppress lung metastasis in hamsters.

A single intradermal administration of soluble leishmanial antigen and plasmid expressing interleukin-12 protects BALB/c mice from Leishmania major infection

In murine leishmaniasis, the induction of the T-helper type 1 (Th1) response contributes to infection resistance, whereas the establishment of the Th2 response makes the mice susceptible to infection. Interleukin-12 (IL-12) plays a pivotal role in the diversification of immune responses to the Th1 type. In this study, we tested whether the co-administration of IL-12 expression plasmid which compose p35 and p40 subunits and soluble leishmanial antigen (SLA) will skew the susceptible BALB/c mice to Th1 response and protect from leishmaniasis. When the mice were intradermally injected with the combination of IL-12 plasmid and SLA 7 days prior to the challenge with 1x10(6) promastigotes of Leishmania major, the local lesions completely healed and the parasite burden in the local lymph nodes significantly decreased. The cured mice attained long-term immunity, and were resistant to any subsequent rechallenge of the lethal dose of the parasite. The protective effect was associated with the development of a Th1 response, as demonstrated by the enhanced level of antigen-specific interferon-gamma (IFN-gamma) and dominant production of IgG2a in the serum. In contrast, the administration of empty plasmid plus SLA or IL-12 plasmid alone failed to protect the disease and shape the Th1 response. Furthermore, the protective efficiency induced by the vaccination was clearly prevented by the injection of either neutralizing anti-IL-12 mAb or anti-IFN-gamma mAb. The IL-12 expression plasmid is thus an effective adjuvant for the elicitation of a protective Th1 response against leishmaniasis and is therefore, considered to be appropriate for vaccinations that require the induction of Th1 type immunity.

Liposome-mediated gene transfection of endothelial nitric oxide synthase reduces endothelial activation and leukocyte infiltration in transplanted hearts

BACKGROUND

During cardiac ischemia-reperfusion injury, neutrophilic infiltration of the myocardium is mediated by adhesion molecule expression on activated coronary endothelium. Nitric oxide inhibits neutrophil adhesion to endothelium in vitro by blocking the nuclear factor (NF)-kappaB-dependent transcription of adhesion molecules. We investigated whether intraoperative gene delivery of endothelial nitric oxide synthase (eNOS) into donor hearts before transplantation would have a similar effect on an entire organ.

METHODS AND RESULTS

In an allogeneic rabbit heart transplant model, liposomes complexed to the gene encoding eNOS were infused into the donor coronary circulation before transplantation. By 24 hours after transplantation, calcium-dependent nitrite production was significantly higher in eNOS-transfected donor hearts than in the 3 control groups: donor hearts transfected with empty plasmids alone, donor hearts treated with diluent only, and untransplanted native hearts. Intramyocardial neutrophil and T-lymphocyte populations were halved in eNOS-transfected hearts compared with control donor hearts (P<0.05). Moreover, the prevalence of NF-kappaB activation in microvascular endothelial cells and surrounding cardiac myocytes as well as endothelial vascular cell adhesion molecule-1 and intracellular adhesion molecule-1 expression were all significantly reduced in eNOS-transfected hearts compared with control donor hearts (P<0.01). Without immunosuppression, eNOS-transfected hearts survived longer than controls.

CONCLUSIONS

Intraoperative liposome-mediated gene delivery of eNOS to donor hearts can result in early gene expression sufficient to reduce ischemia-reperfusion injury by inhibiting NF-kappaB activation, adhesion molecule expression, and the early infiltration of leukocytes, all of which may improve graft survival.

Age-dependent exposure to radioactive iodine (131I) in the thyroid and total body of newborn, pubertal and adult fischer 344 rats

Female rats of the Fischer 344 strain at ages of 1, 4 and 9 weeks were exposed to 131I intraperitoneally with activities of 0.38, 1.03 and 3.42 kBq per gram of body weight under the condition of iodine deficiency. The absorbed doses in the thyroid increased linearly depending on the injected activities. Irradiation at 1 week old caused heavier exposure than those at 4 and 9 weeks old by 7.5 and 7.7 times, respectively; however, damage of the thyroid tissue was more obvious in the 4-week-old groups than in the 1-week-old groups. The absorbed doses in the total body were proportional to the square root of the injected activities. The one-week-old groups were exposed more heavily than the 4- and 9-week-old groups by 3.6 and 4.7 times, respectively, shown by the slow excretion of 131I with the values of effective half-life of 131I activity (Teff). An IDD-treatment was not so effective to enhance the 131I absorption in the total body, as in the thyroid. No matter how the iodine concentration in the blood changed, the 1-week-old groups could not react to normalize the level. We drew standard curves, which enabled us to estimate the absorbed doses in the thyroid and the total body in the case of the injected activities of 131I for the newborn, pubertal and adult rats.

Suppression of T(h)1 cell activation and prevention of autoimmune diabetes in NOD mice by local expression of viral IL-10

Insulin-dependent diabetes mellitus in the NOD mouse model is caused by the T cell-mediated autoimmune destruction of pancreatic beta cells. Viral IL-10 (vIL-10), encoded in the Epstein-Barr virus genome, shares many of the anti-inflammatory properties of cellular IL-10, but lacks its immunostimulatory properties. In the present study, we generated transgenic (Tg) NOD mice in which vIL-10 was produced exclusively in pancreatic islets and investigated the effect of vIL-10 on the development of diabetes. The accumulation of lymphocytes around islets was more prominent, but the invasive insulitis decreased in the vIL-10 Tg mice. The incidence of diabetes was markedly reduced in the vIL-10 Tg mice, in clear contrast to the accelerated diabetes seen in the murine IL-10 Tg NOD mice. IL-12p40 and IFN-gamma mRNA levels were decreased in pancreata of the vIL-10 Tg mice, although CD4 mRNA level was markedly increased. These results suggest that locally produced vIL-10 induced leukocyte migration, but inhibited the activation of T(h)1, probably through suppressing the production of IL-12. They indicate that vIL-10 may well be superior to cellular IL-10 in the treatment of autoimmune diabetes. The vIL-10 Tg NOD mice should provide a useful tool for understanding the differential action of vIL-10 versus cellular IL-10.

Mutations of rubella virus vaccine TO-336 strain occurred in the attenuation process of wild progenitor virus

The sequences of the genomes in the TO-336 vaccine strain (TO-336vac) of rubella virus and its wild progenitor virus (TO-336wt) have been determined and compared with each other. There were 21 differences in the nucleotide sequences between the TO-336vac and the TO-336wt: 13 in the nonstructural protein open reading frame (NSP-ORF), five in the structural protein open reading frame (SP-ORF) and three in the untranslated regions (UTRs) (one in each three UTRs). These mutations resulted in amino acid substitutions at ten residues. Of the ten substitutions, eight were in NSP-ORF and two were in the SP-ORF. Of the eight substitutions in NSP-ORF, four (amino acids (aa) 320, 501, 573 and 704) were in the regions of unknown function, two (aa 1154 and 1159) were within the protease motif, and two (aa 1351 and 1559) were within the helicase motif. Both of the two residues (aa 890 and 954) in the SP-ORF were within the E1 gene. The predicted second structure of the 5'UTR of the TO-336vac was identical to that of TO-336wt. Comparing the TO-336 sequences with other four strains, Therien and M33 (wild viruses), and RA27/3 and Cendehill (vaccine viruses), the mutations responsible for attenuation are thought to differ with each vaccine strain. This is the first report of sequencing in a pair of live attenuated rubella vaccines and their wild-type parent.

Novel drug delivery system to bone using acidic oligopeptide: pharmacokinetic characteristics and pharmacological potential

We synthesized fifteen oligopeptides consisting of Asp or Glu conjugated with a fluorescent probe, 9- fluorenylmethylchloroformate (Fmoc). In the in vitro binding assay to putative hydroxyapatite (HA), the affinities of these conjugates depended only on the number of amino acid residues, not on their optical characters (L or D) or their species (Asp or Glu). In an in vivo experiment involving a single i.v. injection of Fmoc-D-Asp oligopeptides into mice, peptides consisting of over six Asp residues were selectively distributed to the bone. Then, we synthesized estradiol-17 beta-succinate-(L-Asp)6 [E2-(L-Asp)6] and studied its pharmacokinetic characteristics and its antiosteoporotic effects on ovariectomized (OVX) mice. Although the distribution volume of E2-(L-Asp)6 was significantly smaller than that of E2, E2-(L-Asp)6 was selectively distributed in the bone after i.v. injection and gradually decreased during 7 days. E2-(L-Asp)6 effectively prevented OVX-induced bone loss, without altering the uterine weight, in the dosage range of 0.11 to 1.1 mumol/kg once a week, while E2 increased both the bone mineral density and uterine weight at 0.37 mumol/kg every third day. The results suggest that acidic oligopeptide may be useful for drug delivery to bone and E2-(L-Asp)6 is a good candidate as an anti-osteoporosis drug without the adverse side effects of E2.

Inhibitory effect of liposomal MDP-Lys on lung metastasis of transplantable osteosarcoma in hamster

MDP-Lys (N2-[(N-acetylmuramyl)-L-alanyl-D-isoglutaminyl]-N6-stearoyl-L-lysine), a macrophage activator, is a lipophilic derivative of muramyl dipeptide (MDP). Multilamellar liposome incorporated MDP-Lys was prepared using phosphatidylcholine and phosphatidylserine by conventional film method, and its inhibitory effect on lung metastasis was compared with MDP-Lys as a solution in hamster's osteosarcoma. The lung metastatic rates after transplantation of the tumor to a lower extremity, in which the extremity was amputated 3 weeks later, were 50% and 100% 3 and 7 weeks, respectively, after transplantation. The rates after amputation were reduced by the treatment with MDP-Lys proportionally to the logarithmic MDP-Lys dose, and the rates 7 weeks after transplantation were 55% and 60%, respectively, in the MDP-Lys solution (50 microg/day) and liposomal MDP-Lys (20 microg twice/week) groups. Fifty percent of hamsters treated with liposomal MDP-Lys survived for more than 6 months. Considering that hamsters had a lung metastasis rate of 50% before MDP-Lys treatment, liposomal MDP-Lys given at a dose of 20 microg twice/week was effective for inhibiting lung metastasis at a far lower dose of MDP-Lys than that given as a solution (40 microg vs. 350 microg per week). No significant side effect of liposomal MDP-Lys, as evaluated by the comparison of body weight changes among differently treated hamsters, was detected. This greater inhibitory effect of liposomal MDP-Lys can be considered to be due to the longer retention of the liposomal form in the lung.

IL-12 plays a pathologic role at the inflammatory loci in the development of diabetes in NOD mice

Accumulating evidence suggests that CD4(+)T helper type 1 (Th1) cells play a major role in the development of insulin-dependent diabetes mellitus (IDDM) in the non-obese diabetic (NOD) mouse model. Interleukin (IL)-12 is a potent immunoregulatory molecule that is a key determinant of T-cell differentiation into Th1 cells, and has been implicated in the development of IDDM. To investigate the role of IL-12 that is locally produced by islet-infiltrating cells in the development of IDDM, we generated transgenic NOD mice in which the IL-12 p40 homodimer, a natural antagonist of IL-12, was produced exclusively in islets without affecting the levels of IL-12 p40 in the systemic circulation. We found that the incidence of diabetes was significantly reduced in these transgenic mice. These results clearly demonstrate that IL-12 locally produced by islet-infiltrating cells plays a critical role in the development of IDDM.

Studies on the evaluation of municipal waste management systems

The municipal waste disposal system is at a turning point now, because full-scale efforts are demanded to approach the goal of 'the construction of a waste-recycling society'. An attempt was made to evaluate municipal solid waste management systems with easier indexes in the model area. This study includes two evaluation systems. One evaluation system (case 1) is based on the analysis of waste management costs. Different waste disposal systems can be easily evaluated by comparing the waste disposal costs associated with them. However, it seems risky to rate cities only by the results of an analysis of the waste disposal cost data, since the municipalities build, acquire or expand facilities independently from one another. The associated costs are not summed in a uniform way by all municipalities and for other reasons. The other evaluation system (case 2) is based on the 'amenity and comfort ranking of cities' (Keizai 1998). Judgment by one evaluation index alone for a waste disposal system seems risky since the data in that case are insufficient for proper evaluation of a city. Hence, it is desirable to use two or more indices representative of a future ideal system. The results of the study demonstrated that Toyo Keizai's method of 'amenity and comfort ranking of cities' is better than the method of comparing solid waste management costs.