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Dive into the research topics where Nlandu Roger Ngatu is active.

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Featured researches published by Nlandu Roger Ngatu.


Annals of Allergy Asthma & Immunology | 2012

Anti-inflammatory effects of sacran, a novel polysaccharide from Aphanothece sacrum, on 2,4,6-trinitrochlorobenzene-induced allergic dermatitis in vivo

Nlandu Roger Ngatu; Maiko K. Okajima; Maki Yokogawa; Ryoji Hirota; Masamitsu Eitoku; Basilua Andre Muzembo; Narongpon Dumavibhat; Mikiro Takaishi; Shigetoshi Sano; Tatsuo Kaneko; Takumi Tanaka; Hiroyuki Nakamura; Narufumi Suganuma

BACKGROUND Sacran is a newly discovered sulfated polysaccharide extracted from an algae, Aphanothece sacrum, grown in a river of the Kyushu region in Japan. OBJECTIVE To evaluate sacrans inhibitory effect in 2,4,6-trinitrochlorobenzene (TNCB)-induced allergic dermatitis in NC/Nga mice. METHODS Sacran was extracted by acid and alkaline treatment of A sacrum cyanobacterial biomaterials. To sensitize mice, 150 μL of 5% TNCB was applied epicutaneously on the abdomen of each mouse on day 1 and challenged with 15 μL of 1% TNCB applied on the ear skin of mice on day 8 and then every other day to induce skin lesions. Serum levels of inflammatory markers were measured and histopathologic examination of ear skin specimens performed. On the other hand, sacrans transepidermal water loss was evaluated in 11 volunteer women with dry skin. RESULTS Epicutaneous application of sacran in mice has significantly inhibited the development of allergic dermatitis skin lesions and reduced the number of scratching behavior episodes (P < .01). In addition, sacran efficiently inhibited IgE (P < .001), tumor necrosis factor α (P = .02), interleukin 4, interleukin 5, and interferon γ (P < .01; vs buffer in the TNCB group) production and eosinophilic infiltration in the chemical allergen-exposed ear skin. In addition, sacran-treated body regions of human volunteers with dry skin significantly reduced transepidermal water loss levels compared with exogenous hyaluronic acid (P < .01), which is known to improve skin moisture and exert skin barrier repair activity. CONCLUSIONS This study suggests that sacran exerts anti-inflammatory effects by improving skin barrier function and reducing T(H)2 cytokine production.


Geriatrics & Gerontology International | 2013

Mini Nutritional Assessment and functional capacity in community-dwelling elderly in Rural Luozi, Democratic Republic of Congo

Muzembo Basilua Andre; Narongpon Dumavibhat; Nlandu Roger Ngatu; Masamitsu Eitoku; Ryoji Hirota; Narufumi Suganuma

Aim:  Good nutrition is beneficial both for the health and the functional capacity of the elderly. However, malnutrition is a serious health problem among the elderly, particularly the elderly living in rural areas in many developing countries. The aim of the present study was to carry out a cross‐sectional study of the elderly in the city of Luozi, Democratic Republic of Congo, through the use of the long and the short forms of the Mini Nutritional Assessment (MNA) scale.


Inhalation Toxicology | 2012

Limonene inhalation reduces allergic airway inflammation in Dermatophagoides farinae-treated mice

Ryoji Hirota; Hiroyuki Nakamura; Sabah Asif Bhatti; Nlandu Roger Ngatu; Basilua Andre Muzembo; Narongpon Dumavibhat; Masamitsu Eitoku; Masayoshi Sawamura; Narufumi Suganuma

Limonene is one of the main flavonoids which is reported to inhibit the inflammatory response by suppressing the production of reactive oxygen species. The aim of this study was to evaluate whether limonene can inhibit Dermatophagoides farinae-induced airway hyperresponsiveness (AHR), eosinophilic infiltration and other histological changes in the lung, T helper (Th) 2 cytokine production and airway remodeling in a mice model of asthma. Treatment with limonene significantly reduced the levels of IL-5, IL-13, eotaxin, MCP-1, and TGF-β1 in bronchoalveolar lavage fluid. The goblet cell metaplasia, thickness of airway smooth muscle, and airway fibrosis were markedly decreased in limonene-treated mice. Furthermore, AHR to acetylcholine was significantly abrogated in limonene-treated mice. These results indicate that limonene has a potential to reduce airway remodeling and AHR in asthma model.


Allergology International | 2012

Anti-allergic effects of Vernonia amygdalina leaf extracts in hapten-induced atopic dermatitis-like disease in mice.

Nlandu Roger Ngatu; Maiko K. Okajima; Maki Yokogawa; Ryoji Hirota; Mikiro Takaishi; Masamitsu Eitoku; Basilua Andre Muzembo; Asif Bhati Sabah; Takao Saruta; Mitsuhiko Miyamura; Tatsuo Kaneko; Shigetoshi Sano; Narufumi Suganuma

BACKGROUND Atopic dermatitis (AD) is a chronic inflammatory skin disease characterized by pruritic and eczematous skin lesions. In this study, AD-like disease was induced in NC/Nga mice so as to evaluate the anti-allergic effects of Vernonia amygdalina leaf extracts (VAM). METHODS Forty NC/Nga mice were purchased for each of the two protocols (prophylactic and curative) of the study. Mice were randomly divided in groups of five or six after sensitization with 5% trinitrochlorobenzene (TNCB): aqueous extracts (VAM1), methanolic extracts (VAM2), hydrocortisone (HCT), buffer for the control (TNCB) and the normal mice (NORM) groups. RESULTS As for HCT, VAM1 and VAM2-pretreated mice showed significantly lower number of scratching behavior episodes (p < 0.01; vs. TNCB) following TNCB challenge. In addition, VAM1, VAM2 exerted a significant inhibitory effect on the development of AD skin symptoms (vs. TNCB group; p < 0.001), the production of IgE, TNF-alpha (p < 0.05), IL-5 and IFN-gamma (p < 0.01) (vs. TNCB group) and on the increase in ear thickness (p < 0.05) in prophylactic protocol. In the AD curative protocol, topical VAM1, VAM2 markedly improved skin lesions such as erythema/hemorrhage (p < 0.05), scaling/dryness, erosion/excoriation (p < 0.01) (vs. TNCB mice). Furthermore, a significant decrease in ear thickness was noted in VAM1, VAM2, HCT groups (vs. TNCB group; p < 0.05) as well as the serum total IgE, MCP-1 (p < 0.01) and eotaxin (p < 0.05). VAM2 also improved chronic eczema dermatitis skin symptoms in a patient. CONCLUSIONS Results from this report suggest that VAM extracts, known as ERK pathway inhibitor, prevent and improve atopic/eczema dermatitis syndrome.


American Journal of Infection Control | 2012

Practice of universal precautions and risk of occupational blood-borne viral infection among Congolese health care workers

Nlandu Roger Ngatu; Elaine Kornblat Phillips; Okitotsho Stanislas Wembonyama; Ryoji Hirota; Nsolo Joseph Kaunge; Lukuke Hendrick Mbutshu; Jane Perry; Toru Yoshikawa; Janine Jagger; Narufumi Suganuma

The extent of occupational injuries among health care workers in central Africa, particularly in the Democratic Republic of Congo, is not documented. We sought to determine the incidence of percutaneous injury and exposure to blood and other body fluids in Congolese urban and rural hospitals in the previous year. Our data show high rates of percutaneous injury and exposure to blood and other body fluids, reflecting poor safety conditions for most Congolese health care workers.


Environment International | 2015

Selenium and exposure to fibrogenic mineral dust: A mini-review

Basilua Andre Muzembo; Yoji Deguchi; Nlandu Roger Ngatu; Masamitsu Eitoku; Ryoji Hirota; Narufumi Suganuma

Individuals exposed to fibrogenic mineral dust may exhibit an impaired antioxidant system and produce high levels of reactive oxygen and nitrogen species through immune cells, contributing to the perturbation of immune cell function, inflammation, fibrosis and lung cancer. The lung diseases which are caused by inhalation of fibrogenic mineral dust, known as pneumoconioses, develop progressively and irreversibly over decades. At the moment there is no known cure. The trace element selenium has potent antioxidant and anti-inflammatory properties mediated mainly through selenoproteins. Research has demonstrated that selenium has the ability to protect against cardiovascular diseases; to kill cancer cells in vitro and reduce cancer incidence; and to immunomodulate various cellular signaling pathways. For these reasons, selenium has been proposed as a promising therapeutic agent in oxidative stress associated pathology that in theory would be beneficial for the prevention or treatment of pneumoconioses such as silicosis, asbestosis, and coal workers pneumoconiosis. However, studies regarding selenium and occupational lung diseases are rare. The purpose of this study is to conduct a mini-review regarding the relationship between selenium and exposure to fibrogenic mineral dust with emphasis on epidemiological studies. We carried out a systematic literature search of English published studies on selenium and exposure to fibrogenic mineral dust. We found four epidemiological studies. Reviewed studies show that selenium is lower in individuals exposed to fibrogenic mineral dust. However, three out of the four reviewed studies could not confirm cause-and-effect relationships between low selenium status and exposure to fibrogenic mineral dust. This mini-review underscores the need for large follow-up and mechanistic studies for selenium to further elucidate its therapeutic effects.


BMC Immunology | 2011

Goishi tea consumption inhibits airway hyperresponsiveness in BALB/c mice

Ryoji Hirota; Nlandu Roger Ngatu; Mitsuhiko Miyamura; Hiroyuki Nakamura; Narufumi Suganuma

BackgroundAirway hyperresponsiveness (AHR) is one of the important traits that characterize bronchial asthma. Goishi tea is a post-heating fermented tea that has been reported to have higher free radical scavenging activity. In this study, we evaluated the prophylactic effects of Goishi tea on AHR in BALB/c mice.ResultsThe number of inflammatory cells in BAL fluid was considerably reduced in Goishi tea/Der f and Gallic acid/Der f groups as compared with Tap water/Der f group. Regarding inflammatory cells in BAL, a significant reduction of eosinophils and neutrophils was observed in Goishi tea-treated mice (p < 0.01), as well as in the Gallic acid/Der f group (p < 0.05), as compared with Tap water/Der f group. In asthmatic mice (Tap water/Der f group), the intensity of airway resistance increased simultaneously with the increase in acetylcholine concentration in a dose-dependant way. AHR was significantly inhibited in Goishi tea/Der f and Gallic acid/Der f (p < 0.01) groups as compared with the Tap water/Der f group. Regarding serum specific-IgG1, significantly lower levels of this antibody were observed in Goishi tea/Der f and Gallic acid/Der f groups as compared with the Tap water/Der f group (p < 0.05). In addition, adiponectin level was significantly higher in the Goishi tea group as compared with the Tap water treated mice (p < 0.01).ConclusionsThe results suggest that Goishi tea consumption exerted an inhibitory effect on eosinophilic and neutrophilic infiltration in the lung, attenuated the increase in airway resistance and increased the production of adiponectin; thus reducing Der f induced allergic inflammatory process in mice.


Journal of Occupational Health | 2015

Workplace Violence towards Congolese health care workers: a survey of 436 healthcare facilities in Katanga province, Democratic Republic of Congo

Basilua Andre Muzembo; Lukuke Hendrick Mbutshu; Nlandu Roger Ngatu; Kaj Francoise Malonga; Masamitsu Eitoku; Ryoji Hirota; Narufumi Suganuma

Workplace violence towards Congolese health care workers: A survey of 436 healthcare facilities in Katanga province, Democratic Republic of Congo: Basilua Andre MUZEMBO, et al. Division of Social Medicine, Department of Environmental Medicine, Kochi Medical School, Kochi University—


Geriatrics & Gerontology International | 2012

Assessment of lifestyle effect on oxidative stress biomarkers in free-living elderly in rural Japan

Basilua Andre Muzembo; Dumavibhat Narongpon; Nlandu Roger Ngatu; Masamitsu Eitoku; Ryoji Hirota; Narufumi Suganuma

Background:  Oxidative stress is believed to play a crucial role in aging and age‐related diseases, and is widely thought to increase morbidity and mortality in the elderly. Assessment of biomarkers of oxidative stress, such as 8‐isoprostane and 8‐hydroxy‐2‐deoxyguanosine, are considered to be useful in predicting disease risks at the population level.


Journal of Epidemiology | 2017

Epidemiology of ebolavirus disease (EVD) and occupational EVD in health care workers in Sub-Saharan Africa: Need for strengthened public health preparedness

Nlandu Roger Ngatu; Ntumba Jean-Marie Kayembe; Elayne Kornblatt Phillips; Joa Okech-Ojony; Masika Patou-Musumari; Mukunda Gaspard-Kibukusa; Ndona Madone-Mandina; Mabasi Godefroid-Mayala; Lubogo Mutaawe; Casimir Manzengo; Dimosi Roger-Wumba; Sayumi Nojima

Ebolavirus disease (EVD) is a severe contagious disease in humans, and health care workers (HCW) are at risk of infection when caring for EVD patients. This paper highlights the epidemiologic profile of EVD and its impact on the health care workforce in Africa. A documentary study was conducted which consisted of a review of available literature regarding the epidemiology of EVD, occupational EVD (OEVD), and work safety issues in Sub-Saharan Africa; the literature findings are enriched by field experiences from the authors. EVD outbreaks have already caused 30,500 cases in humans of whom 12,933 died (as of September 9, 2015), and the number of infected HCW has dramatically increased. All eight HCW infected during the 2014 outbreak in Democratic Republic of the Congo died, whereas during the recent West African EVD epidemic more than 890 HCW were infected, with a case fatality rate of 57%. Occupational exposure to blood and other body fluids due to inadequate use of personal protective equipment and needle stick or sharp injuries are among factors that contribute to the occurrence of OEVD. Prevention of OEVD should be one of the top priorities in EVD outbreak preparedness and management, and research should be conducted to elucidate occupational and other factors that expose HCW to EVD. In addition to regularly training HCW to be adequately prepared to care for patients with EVD, it is critical to strengthen the general health care system and improve occupational safety in medical settings of countries at risk.

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Maiko K. Okajima

Japan Advanced Institute of Science and Technology

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Tatsuo Kaneko

Japan Advanced Institute of Science and Technology

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Mamoru Tanaka

Kawasaki University of Medical Welfare

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