Masaki Sanaka

Josai International University, Tiba, Chiba, Japan

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Publications (98)308.49 Total impact

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    ABSTRACT: Aim: To compare the impact of the right recumbent position with the sitting position on gastric emptying of water. Methods: In eight healthy male volunteers, the 13C acetate breath test was performed twice to assess gastric emptying of 100 mL tap water. Subjects were seated in one test and lying on their right side in the other. In both positions, pulmonary (13)CO(2) exhalation curves were obtained by plotting breath data against time. Percent gastric retention curves were created by analyzing data using the Wagner-Nelson protocol. Results: No significant posture effect was found in pulmonary (13)CO(2) output curves (P = 0.2150), whereas a significant effect was seen in gastric retention curves (P = 0.0315). The percent retention values at 10 min and 15 min were significantly smaller when subjects were in the right recumbent position compared with the seated position (P < 0.05). Our results verified the accelerating effect of the right recumbent position on gastric emptying of non-nutritive solutions. Concerning clinical implications, this study suggests that placing patients with acute pain on their right side after oral administration of analgesic drugs in solution is justified as an effective practice for rapid pain relief. For patients with gastrointestinal reflux symptoms, sleeping in the right recumbent position may reduce nocturnal symptoms, as delayed gastric emptying can cause reflux symptoms. Conclusion: Gastric emptying of water occurs more quickly when a subject lies on the right side compared with sitting.
    World Journal of Gastroenterology 01/2013; 19(3):362-365. DOI:10.3748/wjg.v19.i3.362 · 2.37 Impact Factor
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    ABSTRACT: Background/aims: In this pilot study, a new breath test system for gastric emptying study has been proposed. Methodology: The system involves 13C-uracil as a novel tracer and the Wagner-Nelson method for analyzing breath data. Results: In three healthy volunteers, the new breath system allowed quantification of gastric emptying profiles as accurately as the scintigraphic technique. Conclusions: Further validation studies with a lager sample size are needed.
    Hepato-gastroenterology 09/2012; 59(118):1710-1. DOI:10.5754/hge10839 · 0.93 Impact Factor
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    ABSTRACT: Background: 13C octanoate breath test has currently been accepted as a simple and noninvasive method for assessing gastric emptying of solids. However, the results show difference with those obtained by scintigraphy. Our previous researches show that the Wagner-Nelson (WN) method, a novel pharmacological technique which allows estimation of pharmacodynamic status of drugs from excreted specimen, is applicable to the gastric emptying breath test. Using this method, the above diversity between breath test and scintigraphy can be reduced. Methods: The purposes of this study was to investigate impacts of postprandial walking on gastric emptying using WN method compared with conventional method. Twelve healthy volunteers who have neither past history of gastrointestinal surgery, medications, nor symptoms were enrolled as participants. After an overnight fast, participants consumed a 330-kcal-based cake containing 100mg 13C-octanoate with 200ml water within 10 min, and breath samples were collected every 15 min for 4.0 h postprandially. They underwent breath test twice: on one occasion, they kept sitting for 2 hours, and on another occasion, they was encouraged to walk for the first 0.5 h and to keep sitting for the next 1.5h. On the both occasion, the participants were permitted to do daily activity for the last 2 hours. The half emptying time (T1/2) were calculated as conventional parameters. The WN equation is F(t) = (A(breath)(t) + C(t)/0.65)/A(breath)(infinity), where F(t) is a fractional dose of the [(13)C] label emptied, C(t) is the [(13)CO(2)] excretion (% dose/h), A(breath)(t) is the area under the C(t) curve (% dose) and A(breath)(infinity) is the ultimate [(13)CO(2)] recovery in breath (% dose). The percentage gastric retention was estimated as 100 x (1 - F(t)), and T1/2 was calculated. Result: The study showed that postprandial walking have tendency to enhance gastric emptying when the conventional method was used (T1/2; 225.0 vs 150.6 min, p=0.052). The trend showed significance when the WN method was used (T1/2; 66.1 vs 41.1 min, p=0.022). Additionally, the WN method showed subtle change of gastric emptying which could not be detected by the conventional method. Conclusion: The present study indicates that gastric emptying of solid meal is accelerated by postprandial walking. The WN method is superior in showing subtle difference of gastric emptying.
    Gastroenterology 05/2010; 138(5). DOI:10.1016/S0016-5085(10)62245-7 · 16.72 Impact Factor
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    M Sanaka ·

    Neurogastroenterology and Motility 03/2010; 22(3):358; author reply 359. DOI:10.1111/j.1365-2982.2010.01469.x · 3.59 Impact Factor
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    ABSTRACT: Upper gastrointestinal hemorrhage (UGIH) is an urgent disease that is often encountered in daily medical practice. Endoscopic hemostasis is currently indispensable for the treatment of UGIH. Initially, when UGIH is suspected, a cause of UGIH is presumed from the medical interview and physical findings. After ample primary treatment, urgent endoscopy is performed. Many methods of endoscopic hemostasis are in wide use, including hemoclip, injection and thermo-coagulation methods. Although UGIH develops from a wide variety of diseases, such as esophageal varices and gastric and duodenal ulcer, hemostasis is almost always possible. Identification of the causative diseases, primary treatment and characteristic features of endoscopic hemostasis are needed to allow appropriate treatment.
    02/2010; 2(2):54-60. DOI:10.4253/wjge.v2.i2.54
  • Masaki Sanaka · Koji Nakada ·
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    ABSTRACT: A stable isotope ([(13)C]) breath test is a promising method for assessing gastric emptying, but it has not been pervasive yet in Japan. We think that there are some barriers to its popularization, including the uncertainty concerning its theoretical backgrounds, the ambiguity of analyzing and interpreting the data, and the lack of standard protocols for breath sampling. The aim of the present review is to break through these barriers. We hope this article could make the [(13)C]-gastric breath test more maneuverable for and more accessible to researchers and clinicians.
    01/2010; 46(6):267-80. DOI:10.1540/jsmr.46.267
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    Masaki Sanaka · Takatsugu Yamamoto · Yasushi Kuyama ·
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    ABSTRACT: The proton pump inhibitor (PPI) is widely used for the treatment of gastroesophageal reflux disease, peptic ulcer diseases, and functional dyspepsia. The pathogenesis of these acid-related and/or functional upper gastrointestinal disorders is potentially associated with abnormal gastric emptying. To date, variable effects of PPIs on gastric emptying have been reported. Therefore, it is relevant to gather and analyze published information on this topic. A systematic literature search has been performed, showing that the delaying effect of PPIs on gastric emptying of solid meals is consistent, whereas the effect of PPIs on the emptying of liquids is inconsistent. The underlying mechanisms whereby PPIs may affect gastric emptying have been discussed, most of which still remain hypothetic. Gastric emptying of solids involves a process of peptic hydrolysis. PPIs impair the hydrolytic digestion by inhibiting acid-dependent peptic activity, thereby delaying the solid emptying. Gastric emptying of liquids largely depends on volume and energy density of intragastric contents. PPIs variably modify the volume and the energy density by reducing gastric fluid secretion, thereby modifying the liquid emptying in an unpredictable manner. Hypergastrinemia has been considered to delay gastric emptying, but it seems of minor importance in the regulation of gastric emptying during PPI use. The delayed emptying of solids due to PPI therapy may have clinical implications in the management of gastroesophageal reflux disease, functional dyspepsia, as well as diabetes.
    Digestive Diseases and Sciences 12/2009; 55(9):2431-40. DOI:10.1007/s10620-009-1076-x · 2.61 Impact Factor
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    ABSTRACT: Although there have been many studies that showed a close association between gastroesophageal reflux disease (GERD) symptoms and chronic cough, it has been unknown whether acute cough is also associated with GERD. The aim of this study was to evaluate the relationship between GERD and respiratory symptoms in general practice. 1725 consecutive patients who first attended our hospital were enrolled in the present study. They were asked to respond the F-scale questionnaire regardless of their chief complaints. Over all, 656 (38%) patients were diagnosed as GERD and 226 (13%) had respiratory symptoms. Patients with respiratory symptoms had GERD symptoms more frequently than patients without respiratory symptoms (p < 0.05). Forty-three (37%) of 115 patients with acute cough and 48 (43%) of 111 with nonacute cough had GERD symptoms, suggesting that development of GERD is not associated with the period of respiratory symptoms. Patients with respiratory symptoms are at a significantly increased risk of developing GERD. Whether or not treatment for GERD or respiratory diseases is useful for the prevention of respiratory symptoms and GERD, respectively, should not be driving management decisions in primary care.
    International Journal of General Medicine 11/2009; 1:59-63.
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    ABSTRACT: The usefulness of the typical direct methods involving duodenal intubation, such as the secretin and secretin-cholecystokinin tests, in the diagnosis of exocrine pancreatic dysfunction is widely accepted. However, these diagnostic tests tend to be avoided because of their technical complexity and the burden on patients. Recently, a simple breath test was developed for assessment of exocrine pancreatic function employing 13C-dipeptide [i.e., benzoyl-L-tyrosyl-[1-13C] alanine (Bz-Tyr-Ala)]. Although alcohol abuse causes pancreatic damage in humans, this has been unclear in rats. The aim of the study is to evaluate the effect of ethanol exposure beginning at an early age on extra-pancreatic secretory function in rats. Twelve female rats of the F344 strain aged 12 months were used. Seven rats were fed on a commercial mash food with 16% ethanol solution (Japanese Sake) as drinking-fluid since at 29 days of age (ethanol group). The remaining five rats were fed on a nutrient-matched isocaloric diet with water as drinking-fluid (control group). After 24-hr fasting, rats are orally administrated 1cc of water containing sodium 13C-dipeptide (5 mg/kg) and housed in an animal chamber. The expired air in the chamber is collected in a breath-sampling bag using a tube and aspiration pump. The 13CO2 concentration is measured using an infrared spectrometer at 10-min interval for 120 min and expressed as delta per mil. The breath 13CO2 level increased and peaked at 20 min in both two groups. In general, 13CO2 excretion peaked rapidly and also decreased sooner in ethanol rats than in control rats. The mean value of the maximal 13CO2 excretion is 34.7 per mil in ethanol rats, greater than in control rats (31.4 per mil), but the difference did not reach the statistically significance. Chronic ethanol feeding beginning at an early age does not affect extra-pancreatic secretory function in rats.
    North American Journal of Medical Sciences 10/2009; 1(5):239-43. DOI:10.4297/najms.2009.5239
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    ABSTRACT: During esophageal acid clearance, salivation plays an important role in defending the esophageal mucosa. Mosapride, an agent used in chronic, long-term therapy of gastro-esophageal reflux disease (GERD) was regarded as mediating its efficacy through prokinetic properties. Rebamipide is also widely used as an anti-gastritis and anti-ulcer agent in GERD patients with chronic gastritis. The aim of this study is to investigate the effects of rebamipide, mosapride, and risperidone on the salivation induced by pilocarpine. The experiments were conducted on 4-week male SD rats (120-150g). The salivation was induced by intraperitoneally administrated pilocarpine and saliva was collected using preweighted small cotton balls inserted into the animal's mouth every 30 min for 180 min. Thirteen minutes before intraperitoneal administration of pilocarpine, rebamipide, mosapride, and risperidone were administered intraduodenally. Control rats were conducted by intraperitoneal administration of saline and intraduodenal administration of 0.5% methylcellulose solution. The saliva weight at 0-30 min was significantly (p<0.01) increased after administration of pilocarpine, compared to control rats. An additional administration of mosapride and rebamipide increased the saliva weight at 0-30 min. The total volume of saliva for 150 min after administration of pilocarpine was the highest after preadministration of rebamipide, followed by mosapride, and risperidone. Increase in salivation produced by i.p. pilocarpine was enhanced by preadministration of rebamipide and mosapride.
    North American Journal of Medical Sciences 08/2009; 1(3):121-4.
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    ABSTRACT: Despite a close association between gastrointestinal motility and sex hormones, it has been unknown whether ovarian hormones affect absorption and metabolism of nutrients. The aim of this study is, therefore, to evaluate metabolism of acetate in rats with age and the influence of ovariectomy on its change. Fourteen female rats of the F344 strain were used, and 13C-acetate breath test was performed at 2, 7 and 13 months of age. Seven rats were ovariectomized at three weeks of age (ovariectomy group) and the remaining seven rats were studied as control group. After 24-hr fasting, rats are orally administrated 1ml of water containing sodium (13)C-acetate (100mg/kg) and housed in an animal chamber. The expired air in the chamber is collected in a breath-sampling bag using a aspiration pump. The (13)CO(2) concentration is measured using an infrared spectrometer for 120 min and expressed as delta per mil. The breath (13)CO(2) excretion increased with time and peaked 30 min in control rats. In ovariectomized rats, thee peak time of (13)CO(2) excretion was prolonged to 40 min at 7 and 13 months of age. Cmax was significantly higher at 2 months of age but lower at 4 months of age in ovariectomized rats than in control rats. Those of two groups became equal at 7 months of age. From the viewpoint of acetate metabolism, removal of ovarian hormones might make rats to be precocious ones and accelerate ageing.
    North American Journal of Medical Sciences 07/2009; 1(2):58-62.
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    ABSTRACT: Alcohol is commonly consumed with, or soon after, a meal that affects gastric emptying and thus, absorption and metabolism of alcohol. The aim of this study is to evaluate the effect of liquid test meal ingested soon after, alcohol ingestion on alcohol metabolism, as is common in the social setting. First, a 100 mL of water containing of 80 mg of 13C-ethanol was administrated orally in 7 healthy subjects, and 200 mL of liquid meal (200 kcal) was administrated 5 min after alcohol ingestion. Breath samples were taken at baseline and at 10-min interval for 150 min. Next, 13C-ethanol breath test was performed without ingestion of liquid meal. Cmax was decreased after ingestion of liquid meal, whereas Tmax was unchanged. The descending gradient of 13CO2 excretion curves after ingestion of liquid meal is parallel to that without liquid meal, while the ascending gradient of 13CO2 excretion curves in the first 10 min had a tendency to be greater after ingestion of liquid meal than without ingestion of liquid meal. A significant delay in breath 13CO2 excretion after ingestion of liquid meal was found and the AUC values were lower after ingestion of liquid meal in each time point, indicating that liquid meal ingested soon after alcohol ingestion may not affect elimination but absorption and/or metabolism of a small amount of alcohol.
    Nihon Arukōru Yakubutsu Igakkai zasshi = Japanese journal of alcohol studies & drug dependence 05/2009; 44(2):94-100.

  • Gastroenterology 05/2009; 136(5). DOI:10.1016/S0016-5085(09)62947-4 · 16.72 Impact Factor

  • Gastrointestinal Endoscopy 04/2009; 69(5). DOI:10.1016/j.gie.2009.03.817 · 5.37 Impact Factor
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    ABSTRACT: Background The patient with colonic obstruction may frequently have bacterial overgrowth and increased breath hydrogen (H2) levels because the bacterium can contact with food residues for longer time. We experienced two cases with intestinal obstruction whose breath H2 concentrations were measured continuously. Case 1 A 70-year-old woman with small bowel obstruction was treated with a gastric tube. When small bowel gas decreased and colonic gas was demonstrated on the plain abdominal radiograph, the breath H2 concentration increased to 6 ppm and reduced again shortly. Case 2 A 41-year-old man with functional small bowel obstruction after surgical treatment was treated with intravenous administration of erythromycin. Although the plain abdominal radiograph demonstrated a decrease of small-bowel gas, the breath H2 gas kept the low level. After a clear-liquid meal was supplied, fasting breath H2 concentration increased rapidly to 22 ppm and gradually decreased to 9 ppm despite the fact that the intestinal gas was unchanged on X-ray. A rapid increase of breath H2 concentration may reflect the movement of small bowel contents to the colon in patients with small-bowel pseudo-obstruction or malabsorption following diet progression. Conclusions Change in breath H2 concentration had a close association with distribution and movement of intestinal gas.
    Biomarker insights 02/2009; 4(4):9-15.
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    ABSTRACT: Gastric bubble is present in approximately 70% of normal chest and abdominal radiograph. Most swallowed air is regurgitated and belching is a physiological phenomenon to expel ingested gas from the stomach and is a common symptom in normal adults. In the present study it was investigated whether gastric bubble detected on abdominal radiograph is associated with GERD symptoms. All of the patients who first attend our hospital were asked to respond the F-scale questionnaire regardless of their chief complaints to diagnose GERD. Plain abdominal films in the erect position were used to measure the size of gastric bubble and to classify the form of gastric bubble into four groups: dome-type; irregular-type; stomach-type; and undetected-type. The quantity of gastric bubble (gastric bubble score) was determined as the pixel value on image collected from hospital's digital database. The gastric bubble score of irregular-type was significant lower than that of dome-type and stomach-type. GERD was most frequently detected in stomach-type group, followed by undetected-type, irregular-type, and dome-type. The mean score of F-scale was significantly higher in stomach-type than in dome-type. It is concluded that gastric bubble detected on plain abdominal films is an informative marker for evaluating the functional disorder of upper digestive tracts. Physicians have to recognize the importance of plain films of the abdomen in the diagnostic process of GERD.
    Hepato-gastroenterology 01/2009; 56(94-95):1566-70. · 0.93 Impact Factor
  • M Sanaka · K Nakada ·
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    ABSTRACT: The physiological and pharmacological aspects of gastric emptying in fertile or pregnant women have been studied. Scintigraphy is the reference method for measuring gastric emptying. However, it should be applied very cautiously to women of childbearing age because of the risk of substantial irratiation. In such a population, paracetamol absorption has been used safely as an index of gastric emptying, but its accuracy has been challenged. The Wagner-Nelson method is a traditional tool used to precisely evaluate drug absorption kinetics. To clarify whether the absorption kinetics of paracetamol assessed by the Wagner-Nelson method is as accurate as scintigraphy in evaluating gastric emptying in young women, gastric emptying of a 200-kcal liquid meal was measured simultaneously by scintigraphy and the paracetamol test in 10 healthy young female volunteers. Paracetamol absorption systemically overestimated the rate of gastric emptying measured by scintigraphy. By introducing a correction factor into the paracetamol test, the overestimation could be adjusted. The paracetamol test with Wagner-Nelson analysis can be a safe and accurate method for measuring gastric emptying in women of childbearing age.
    Methods and Findings in Experimental and Clinical Pharmacology 01/2009; 30(10):753-6. DOI:10.1358/mf.2008.30.10.1316828 · 0.77 Impact Factor

  • Clinical Nutrition Supplements 12/2008; 3:87-87. DOI:10.1016/S1744-1161(08)70200-X

  • Clinical Nutrition Supplements 12/2008; 3:88-88. DOI:10.1016/S1744-1161(08)70203-5
  • Takatsugu Yamamoto · Taro Ishii · Masaki Sanaka · Yasushi Kuyama ·
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    ABSTRACT: Accurate diagnosis of Helicobacter pylori infection is essential in today's clinical settings. Additionally, because of the widespread prevalence of this infection, noninvasive and convenient techniques are required for screening purposes. RAPIRUN H. pylori antibody detection kit (Otsuka Pharmaceutical Co., Ltd, Tokyo, Japan) enables a diagnosis within 20 min using a random, single-voided urine specimen. Thus it is especially suited for use in point-of-care settings. The sensitivity and specificity are acceptable and comparable with other available methods. Here we provide an overview of the RAPIRUN kit.
    Expert Review of Molecular Diagnostics 10/2008; 8(5):565-9. DOI:10.1586/14737159.8.5.565 · 3.52 Impact Factor

Publication Stats

698 Citations
308.49 Total Impact Points


  • 2010-2013
    • Josai International University
      Tiba, Chiba, Japan
  • 2008-2010
    • Toho University
      • Department of General Medicine and Emergency Care
      Edo, Tōkyō, Japan
  • 2000-2010
    • Tokyo Metropolitan Komagome Hospital
      Edo, Tōkyō, Japan
  • 1998-2007
    • Teikyo University
      • • Department of Medicine
      • • Department of Internal Medicine
      Edo, Tōkyō, Japan
  • 1997-2006
    • Teikyo University Hospital
      Edo, Tōkyō, Japan
  • 1995-1996
    • Tokyo Medical and Dental University
      • Department of Preventive Medicine
      Edo, Tōkyō, Japan