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Natural virus infections in cynomolgus monkeys

Suzuki M

Jpn. J. Med. Sci. Biol., 1981 Aug;34(4):261-3.
PMID: 7321300
Reproductive pattern of the sun bear (Helarctos malayanus) in Sarawak, Malaysia

Onuma M, Suzuki M, Ohtaishi N

J Vet Med Sci, 2001 Mar;63(3):293-7.
PMID: 11307930

Fecal progesterone assays were conducted in 3 captive female sun bears (Helarctos malayanus) segregated from males to characterize the species-specific reproductive pattern in their original distribution area in Sarawak, Malaysia. Peaks of fecal progesterone concentrations were observed once annually, and lactation was observed after increasing progesterone concentrations in all females without mating stimulus. These results suggest that sun bears in Sarawak, Malaysia, may have a seasonal reproductive pattern and ovulation was noted to occur spontaneously, followed by pseudopregnancy.
Possible conservation units of the sun bear (Helarctos malayanus) in Sarawak based on variation of mtDNA control region

Onuma M, Suzuki M, Ohtaishi N

Jpn. J. Vet. Res., 2006 Nov;54(2-3):135-9.
PMID: 17201199

The mitochondrial DNA control region of the sun bear (Helarctos malayanus) was sequenced using 21 DNA samples collected from confiscated sun bears to identify conservation units, such as evolutionarily significant units and management units, in Sarawak, Borneo Island. A total of 10 haplotypes were observed, indicating the presence of at least two lineages in the sun bear population in Sarawak. Presumably, these two lineages could represent evolutionarily significant units. However, the geographical distributions of the two lineages remained unknown due to the lack of information regarding the exact capture locations of the confiscated sun bears. It is essential to elucidate the geographical distributions of these lineages in order to create a proper conservation plan for the sun bears in Sarawak. Therefore, further studies examining the haplotype distributions using DNA samples from known localities are essential.
Novel halogenated metabolites from the Malaysian Laurencia pannosa

Suzuki M, Daitoh M, Vairappan CS, Abe T, Masuda M

J Nat Prod, 2001 May;64(5):597-602.
PMID: 11374951

In connection with our chemotaxonomic studies of Malaysian species of the red algal genus Laurencia, the chemical composition of Laurencia pannosa Zanardini was examined. Two halogenated sesquiterpenoids, named pannosanol (1) and pannosane (2), have been isolated along with a halogenated C15-acetogenin, (3Z)-chlorofucin (3). The structures of these compounds were determined from their spectroscopic data (IR, 1H NMR, 13C NMR, 2D NMR, and MS). Pannosanol and pannosane are novel halometabolites with an unusual rearranged chamigrane framework. Antibacterial activities of these metabolites against marine bacteria are also described.
Immunotyping of different strains of Japanese encephalitis virus by antibody-absorption, haemagglutination-inhibition and complement-fixation tests

Okuno T, Okada T, Kondo A, Suzuki M, Kobayashi M, Oya A

Bull World Health Organ, 1968;38(4):547-63.
PMID: 5302450

The immunological characteristics of 26 strains of Japanese encephalitis virus (JEV) isolated in Japan and Malaya between 1935 and 1966 have been investigated mainly by the antibody-absorption variant of the haemagglutination-inhibition test, and to a certain extent also by conventional haemagglutination-inhibition and complement-fixation tests. The antibody-absorption technique shows promise as a routine method for the immunotyping of JEV.At present, two immunotypes can be distinguished. One comprises 2 strains, Nakayama-NIH and I-58, and is designated as the I-58 immunotype. The other immunotype, JaGAr 01, comprises 17 strains which share the characteristics of the JaGAr 01 strain, including one subline of the Nakayama strain, Nakayama-Yakken. The Nakayama-RFVL strain was found to have the characteristics of both immunotypes. The I-58 immunotype differs more markedly from related arboviruses, such as the Murray Valley encephalitis virus and the West Nile Eg101 strain, than does the JaGAr 01 immunotype.Evidence is presented which suggests that a given JEV strain can change immunotype on repeated passage through mice.
Antibacterial halogenated metabolites from the Malaysian Laurencia species

Vairappan CS, Daitoh M, Suzuki M, Abe T, Masuda M

Phytochemistry, 2001 Sep;58(2):291-7.
PMID: 11551553

Two halogenated C15 acetogenins, named lembyne-A and lembyne-B, have been isolated from an unrecorded Laurencia species collected off the Malaysian waters. Their structures were deduced on the basis of spectroscopic evidence. Previously known elatol and iso-obtusol showed potent antibacterial activity against some marine bacteria.
Fulltext Antibacterial activities of a new brominated diterpene from Borneon Laurencia spp

Vairappan CS, Ishii T, Lee TK, Suzuki M, Zhaoqi Z

Mar Drugs, 2010;8(6):1743-9.
PMID: 20631866 DOI: 10.3390/md8061743

In our continuous interest to study the diversity of halogenated metabolites of Malaysian species of the red algal genus Laurencia, we examined the chemical composition of five populations of unrecorded Laurencia sp. A new brominated diterpene, 10-acetoxyangasiol (1), and four other known metabolites, aplysidiol (2), cupalaurenol (3), 1-methyl-2,3,5-tribromoindole (4), and chamigrane epoxide (5), were isolated and identified. Isolated metabolites exhibited potent antibacterial activities against clinical bacteria, Staphylococcus aureus, Staphylococcus sp., Streptococcus pyogenes, Salmonella sp. and Vibrio cholerae.
Fulltext Serological evaluation of malaria patients in Thailand: antibody response against electrophoresed antigenic polypeptides of Plasmodium falciparum

Kano S, Onda T, Matsumoto Y, Buchachart K, Krudsood S, Looareesuwan S, et al.

Southeast Asian J. Trop. Med. Public Health, 1998 Jun;29(2):341-3.
PMID: 9886125

It was reported that a 47kDa antigenic polypeptide of Plasmodium falciparum had been strongly presented by the sera from 1) imported Japanese malaria patients with severe symptoms and 2) symptomatic and parasitemic inhabitants in endemic areas in the Sudan, Malaysia and the Philippines. In the present study, we observed the reactivity of the sera from falciparum malaria patients who had been hospitalized in the Bangkok Hospital for Tropical Diseases, Faculty of Tropical Medicine, Mahidol University, and compared the antibody response against the 47kDa antigenic polypeptide according to the severity of the patients. It was observed that antibodies to this molecule were more commonly shared in sera from severer patients, although the IFAT titers against the whole P. falciparum parasite antigen were lower in the group, which suggested that this antibody against the 47kDa molecule was playing a specific role at a severe stage of the infection. Determination of the immunological features of the antigenic molecules of parasites by this type of sero-epidemiological study will provide a new assay system for evaluation of immune status of individuals in different severity and suggest a way of vaccine development.
Annual changes in fecal estradiol-17beta concentrations of the sun bear (Helarctos malayanus) in Sarawak, Malaysia

Onuma M, Suzuki M, Uchida E, Niiyama M, Ohtaishi N

J Vet Med Sci, 2002 Apr;64(4):309-13.
PMID: 12014574

Fecal estradiol concentrations were measured in three captive unmated female sun bears (Helarctos malayanus) from August 1998 to July 1999 in Sarawak, Malaysia and vaginal smears from one of the females was observed in August 1998 and March 1999. A single peak in fecal estradiol concentration was obvious for each bear in August or September 1998, and there was a much higher percentage of superficial vaginal anuclear cells in August 1998 than in March 1999. These results suggest that sun bears in Sarawak are likely to be a seasonal breeder associated with a peak of estrogen production in August or September.
Primary solitary fibrous tumour of the prostate: A case report and literature review

Okubo Y, Nukada S, Shibata Y, Osaka K, Yoshioka E, Suzuki M, et al.

Malays J Pathol, 2020 Dec;42(3):449-453.
PMID: 33361728

INTRODUCTION: Solitary fibrous tumour (SFT) is a rare mesenchymal tumour with intermediate malignant potential. Although this tumour arises in several sites, prostatic SFT is an extremely rare neoplasm and may prove confusing owing to the lack of clinical experience because of tumour rarity. The diagnosis may be further difficult because SFTs can manifest positive immunoreactivity for CD34 and progesterone receptor, which are known markers of prostatic stromal tumours. Herein, we describe a case of prostatic SFT that was difficult to differentiate from a prostatic stromal tumour of uncertain malignant potential because of positive immunoreactivity to CD34 and progesterone receptor.
CASE REPORT: A 40-year-old Japanese man presented with lower abdominal pain. Computed tomography revealed a prostatic mass; furthermore, prostate core needle biopsy revealed proliferating bland spindle cells, without necrosis or prominent mitoses. Tumour cells were positive for CD34 and progesterone receptor on immunohistochemical analysis; thus, a prostatic stromal tumour of uncertain malignant potential was initially suspected. However, as the tumour cells showed positive immunoreactivity for STAT6, the final diagnosis was an SFT of the prostate. The patient underwent tumour resection, and at the 6-month postoperative follow-up, neither local recurrence nor distant metastasis occurred.
CONCLUSION: For an accurate diagnosis of an SFT of the prostate, STAT6 immunohistochemistry should be conducted for all mesenchymal tumours of the prostate. When STAT6 immunohistochemical analysis is unfeasible, pathologists should be aware that the morphological and immunohistochemical characteristics of SFT variable from case to case and diagnose with combined analysis of several immunohistochemical markers.
Potent antibacterial activity of halogenated compounds against antibiotic-resistant bacteria

Vairappan CS, Kawamoto T, Miwa H, Suzuki M

Planta Med, 2004 Nov;70(11):1087-90.
PMID: 15549668

Common Gram-positive clinical pathogens are showing an increasing trend for resistance to conventional antimicrobial agents. New drugs with potent antibacterial activities are urgently needed to remediate this problem. Halogenated compounds isolated from several species of the red algae genus Laurencia were examined for their antibacterial activity against 22 strains of human pathogenic bacteria, 7 strains of which were antibiotic-resistant bacteria. Four phenolic sesquiterpenes and a polybrominated indole showed wide spectra of antibacterial activity against Gram-positive bacteria including methicillin-resistant Staphylococcus aureus (MRSA), penicillin-resistant Streptococcus pneumoniae, and vancomycin-resistant Enterococcus faecalis and E. faecium (VRE). In addition, laurinterol and allolaurinterol displayed potent bactericidal activity against three strains of MRSA at 3.13 microg mL(-1), and three strains of vancomycin-susceptible Enterococcus, at 3.13 microg mL(-1) and 6.25 microg mL(-1), respectively.
Fulltext The effect of wearing sanitary napkins of different thicknesses on physiological and psychological responses in Muslim females

Mohamed NG, Abidin NZ, Law KS, Abe M, Suzuki M, Muhamed AM, et al.

J Physiol Anthropol, 2014;33:28.
PMID: 25189184 DOI: 10.1186/1880-6805-33-28

Menstruation is associated with significant unpleasantness, and wearing a sanitary napkin (SN) during menses causes discomfort. In addition, many Muslim women use a thick type of SN during menses due to the religious requirement that even disposable SNs be washed before disposal. Therefore, the objective of this study was to measure the physiological and psychological responses to wearing SNs of different thicknesses during menstruation and non-menstruation phases at rest and during physical activity/exercise among Muslim women.
Antibacterial activity of halogenated sesquiterpenes from Malaysian Laurencia spp

Vairappan CS, Suzuki M, Ishii T, Okino T, Abe T, Masuda M

Phytochemistry, 2008 Oct;69(13):2490-4.
PMID: 18718619 DOI: 10.1016/j.phytochem.2008.06.015

During our studies on Malaysian Laurencia species, brominated metabolites, tiomanene, acetylmajapolene B, and acetylmajapolene A were isolated from an unrecorded species collected at Pulau Tioman, Pahang along with known majapolene B and majapolene A. Acetylmajapolene A was a mixture of diastereomers as in the case of majapolene A. Tiomanene may be a plausible precursor for acetylmajapolenes B and A. In addition, three known halogenated sesquiterpenes and two known halogenated C(15) acetogenins were found from other two unrecorded species collected at Pulau Karah, Terengganu and Pulau Nyireh, Terengganu, respectively. Some of these halogenated metabolites showed moderate antibacterial activity against some marine bacteria.
Carbon allocation in a Bornean tropical rainforest without dry seasons

Katayama A, Kume T, Komatsu H, Saitoh TM, Ohashi M, Nakagawa M, et al.

J Plant Res, 2013 Jul;126(4):505-15.
PMID: 23283581 DOI: 10.1007/s10265-012-0544-0

To clarify characteristics of carbon (C) allocation in a Bornean tropical rainforest without dry seasons, gross primary production (GPP) and C allocation, i.e., above-ground net primary production (ANPP), aboveground plant respiration (APR), and total below-ground carbon flux (TBCF) for the forest were examined and compared with those from Amazonian tropical rainforests with dry seasons. GPP (30.61 MgC ha(-1) year(-1), eddy covariance measurements; 34.40 MgC ha(-1) year(-1), biometric measurements) was comparable to those for Amazonian rainforests. ANPP (6.76 MgC ha(-1) year(-1)) was comparable to, and APR (8.01 MgC ha(-1) year(-1)) was slightly lower than, their respective values for Amazonian rainforests, even though aboveground biomass was greater at our site. TBCF (19.63 MgC ha(-1) year(-1)) was higher than those for Amazonian forests. The comparable ANPP and higher TBCF were unexpected, since higher water availability would suggest less fine root competition for water, giving higher ANPP and lower TBCF to GPP. Low nutrient availability may explain the comparable ANPP and higher TBCF. These data show that there are variations in C allocation patterns among mature tropical rainforests, and the variations cannot be explained solely by differences in soil water availability.
Histopathological study of carcinoma showing thymus-like differentiation (CASTLE)

Okubo Y, Sakai M, Yamazaki H, Sugawara Y, Samejima J, Yoshioka E, et al.

Malays J Pathol, 2020 08;42(2):259-265.
PMID: 32860379

INTRODUCTION: Carcinoma showing thymus-like differentiation (CASTLE) is a rare tumour that mainly arises from the thyroid gland, or occasionally, from the head and neck. Although the 10-year survival rate of patients with CASTLE is approximately 80%, local recurrence and distant metastasis are observed in some cases. A recent systematic review for CASTLE indicated that the prognostic factors are treatment-dependent, and postoperative radiotherapy significantly improves patient survival.
CASE REPORT: Herein, we describe and compare three cases of CASTLE, including a case with distant metastasis despite administering postoperative chemotherapy. Thus, the mechanisms underlying metastasis of CASTLE are unclear. This case study helps to elucidate the histopathological risk factors of metastasis in CASTLE.
DISCUSSION: We found that prominent lymphovascular invasion and higher proliferative activities might be risk factors of metastasis in CASTLE. In addition, we have summarised the cytological, morphological, and immunohistochemical features of CASTLE for an accurate diagnosis.
Fulltext The radiobiological effects of He, C and Ne ions as a function of LET on various glioblastoma cell lines

Chew MT, Bradley DA, Suzuki M, Matsufuji N, Murakami T, Jones B, et al.

J Radiat Res, 2019 Mar 01;60(2):178-188.
PMID: 30624699 DOI: 10.1093/jrr/rry099

The effects of the charged ion species 4He, 12C and 20Ne on glioblastoma multiforme (GBM) T98G, U87 and LN18 cell lines were compared with the effects of 200 kVp X-rays (1.7 keV/μm). These cell lines have different genetic profiles. Individual GBM relative biological effectiveness (RBE) was estimated in two ways: the RBE10 at 10% survival fraction and the RBE2Gy after 2 Gy doses. The linear quadratic model radiosensitivity parameters α and β and the α/β ratio of each ion type were determined as a function of LET. Mono-energetic 4He, 12C and 20Ne ions were generated by the Heavy Ion Medical Accelerator at the National Institute of Radiological Sciences in Chiba, Japan. Colony-formation assays were used to evaluate the survival fractions. The LET of the various ions used ranged from 2.3 to 100 keV/μm (covering the depth-dose plateau region to clinically relevant LET at the Bragg peak). For U87 and LN18, the RBE10 increased with LET and peaked at 85 keV/μm, whereas T98G peaked at 100 keV/μm. All three GBM α parameters peaked at 100 keV/μm. There is a statistically significant difference between the three GBM RBE10 values, except at 100 keV/μm (P < 0.01), and a statistically significant difference between the α values of the GBM cell lines, except at 85 and 100 keV/μm. The biological response varied depending on the GBM cell lines and on the ions used.
Monitoring OH-PCBs in PCB transport worker's urine as a non-invasive exposure assessment tool

Haga Y, Suzuki M, Matsumura C, Okuno T, Tsurukawa M, Fujimori K, et al.

Environ Sci Pollut Res Int, 2018 Jun;25(17):16446-16454.
PMID: 29656357 DOI: 10.1007/s11356-018-1927-0

In this study, we analyzed hydroxylated polychlorinated biphenyls (OH-PCBs) in urine of both PCB transport workers and PCB researchers. A method to monitor OH-PCB in urine was developed. Urine was solid-phase extracted with 0.1% ammonia/ methanol (v/v) and glucuronic acid/sulfate conjugates and then decomposed using β-glucuronidase/arylsulfatase. After alkaline digestion/derivatization, the concentration of OH-PCBs was determined by HRGC/HRMS-SIM. In the first sampling campaign, the worker's OH-PCB levels increased several fold after the PCB waste transportation work, indicating exposure to PCBs. The concentration of OH-PCBs in PCB transport workers' urine (0.55~11 μg/g creatinine (Cre)) was higher than in PCB researchers' urine (
Fulltext Potential lethal damage repair in glioblastoma cells irradiated with ion beams of various types and levels of linear energy transfer

Chew MT, Nisbet A, Suzuki M, Matsufuji N, Murakami T, Jones B, et al.

J Radiat Res, 2019 Jan 01;60(1):59-68.
PMID: 30452663 DOI: 10.1093/jrr/rry081

Glioblastoma (GBM), a Grade IV brain tumour, is a well-known radioresistant cancer. To investigate one of the causes of radioresistance, we studied the capacity for potential lethal damage repair (PLDR) of three altered strains of GBM: T98G, U87 and LN18, irradiated with various ions and various levels of linear energy transfer (LET). The GBM cells were exposed to 12C and 28Si ion beams with LETs of 55, 100 and 200 keV/μm, and with X-ray beams of 1.7 keV/μm. Mono-energetic 12C ions and 28Si ions were generated by the Heavy Ion Medical Accelerator at the National Institute of Radiological Science, Chiba, Japan. Clonogenic assays were used to determine cell inactivation. The ability of the cells to repair potential lethal damage was demonstrated by allowing one identical set of irradiated cells to repair for 24 h before subplating. The results show there is definite PLDR with X-rays, some evidence of PLDR at 55 keV/μm, and minimal PLDR at 100 keV/μm. There is no observable PLDR at 200 keV/μm. This is the first study, to the authors' knowledge, demonstrating the capability of GBM cells to repair potential lethal damage following charged ion irradiations. It is concluded that a GBM's PLDR is dependent on LET, dose and GBM strain; and the more radioresistant the cell strain, the greater the PLDR.
Fulltext Curculin exhibits sweet-tasting and taste-modifying activities through its distinct molecular surfaces

Kurimoto E, Suzuki M, Amemiya E, Yamaguchi Y, Nirasawa S, Shimba N, et al.

J Biol Chem, 2007 Nov 16;282(46):33252-33256.
PMID: 17895249 DOI: 10.1074/jbc.C700174200

Curculin isolated from Curculigo latifolia, a plant grown in Malaysia, has an intriguing property of modifying sour taste into sweet taste. In addition to this taste-modifying activity, curculin itself elicits a sweet taste. Although these activities have been attributed to the heterodimeric isoform and not homodimers of curculin, the underlying mechanisms for the dual action of this protein have been largely unknown. To identify critical sites for these activities, we performed a mutational and structural study of recombinant curculin. Based on the comparison of crystal structures of curculin homo- and heterodimers, a series of mutants was designed and subjected to tasting assays. Mapping of amino acid residues on the three-dimensional structure according to their mutational effects revealed that the curculin heterodimer exhibits sweet-tasting and taste-modifying activities through its partially overlapping but distinct molecular surfaces. These findings suggest that the two activities of the curculin heterodimer are expressed through its two different modes of interactions with the T1R2-T1R3 heterodimeric sweet taste receptor.
Fulltext New Marine Antifouling Compounds from the Red Alga Laurencia sp

Oguri Y, Watanabe M, Ishikawa T, Kamada T, Vairappan CS, Matsuura H, et al.

Mar Drugs, 2017 Aug 28;15(9).
PMID: 28846653 DOI: 10.3390/md15090267

Six new compounds, omaezol, intricatriol, hachijojimallenes A and B, debromoaplysinal, and 11,12-dihydro-3-hydroxyretinol have been isolated from four collections of Laurencia sp. These structures were determined by MS and NMR analyses. Their antifouling activities were evaluated together with eight previously known compounds isolated from the same samples. In particular, omaezol and hachijojimallene A showed potent activities (EC50 = 0.15-0.23 µg/mL) against larvae of the barnacle Amphibalanus amphitrite.

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