Dietary herb extract rikkunshi-to ameliorates gastroparesis in Parkinson's disease: a pilot study.

OBJECTIVE: To perform an open trial on the effects of the extract of the dietary herb Rikkunshi-to (RKT) on gastroparesis in Parkinson's disease (PD) patients, using objective parameters given by the (13)C-sodium acetate expiration breath test (gastric emptying study). METHODS: Twenty patients with PD were enrolled into this study. Eleven patients were male and 9 were female, with the following characteristics (mean ± SD): age, 69.4 ± 8.17 years; disease duration, 4.34 ± 4.03 years; modified Hoehn and Yahr stage, 2.37 ± 0.98, and Unified Parkinson's Disease Rating Scale Part 3 motor score, 16.6 ± 7.37. Fourteen patients came to the clinic due to constipation; 16 patients were taking 288 ± 72 mg/day levodopa/carbidopa, 2 were taking dopamine agonists, and the others were not treated yet. All patients underwent the breath test. Statistical analysis was performed using Student's t test. RESULTS: RKT was well tolerated by all patients and none experienced abdominal pain or other adverse effects, except for its bitter taste. RKT significantly reduced the peak time of the (13)C-dose-excess curve (p < 0.05). CONCLUSION: In this pilot trial, we found a significant shortening of the gastric emptying time after administration of the dietary herb extract RKT in PD patients. Further studies examining both gastric emptying and delayed-on in PD are warranted. .

Nizatidine ameliorates gastroparesis in Parkinson's disease: a pilot study.

BACKGROUND: The objective of this work was to perform an open trial of the effects of nizatidine (NZT), a selective histamine H2-receptor antagonist and a cholinomimetic, on gastroparesis in Parkinson's disease (PD) patients, using objective parameters given by a gastric emptying study using a (13) C-sodium acetate expiration breath test. METHODS: Twenty patients with PD were enrolled in the study. There were 13 men and 7 women; aged 68.0 ± 7.72 years; disease duration 5.50 ± 3.62 years. All patients underwent the breath test and a gastrointestinal questionnaire before and after 3 months of administration of NZT at 300 mg/day. Statistical analysis was performed by Student t test. RESULTS: NZT was well tolerated by all patients and none had abdominal pain or other adverse effects. NZT significantly shortened Tmax ((13) C) (the peak time of the (13) C-dose-excess curve) (P < 0.05). CONCLUSIONS: Although this is a pilot study, we found a significant shortening of gastric emptying time after administration of NZT in PD patients.

[Gastrointestinal dysfunction has important implications for plasma L-dopa concentrations in Parkinson's disease].

Gastrointestinal motility dysfunctions including anorexia, nausea, heartburn, bloating, etc. are common and frequent complication of Parkinson's disease (PD). Degeneration of enteric nerves system is supposed to be a pathogenesis of these symptoms. Impairment of gastric emptying (GE) leads to retardation of the drug delivery from stomach to jejunum, so that PD patients with GE impairment show the delayed elevation of plasma L-dopa concentration. Disturbance of L-dopa absorption will result in wearing-off and delayed-on, and these are called motor fluctuation. In our investigation, 69% of PD patients who exhibited delayed elevation of plasma L-dopa concentration complicated GE impairment, whereas only 22% of patients with normal L-dopa level showed GE retardation (p = 0.0044, χ(2)-test). Serotonin 5-HT4 agonist and dopamine D2 antagonist are useful to improve GE impairment in PD. These drugs stimulate the postganglionic cholinergic fiber to release acetylcholine amongst the enteric nerves system and facilitate the gastrointestinal tract. Rikkunshi-to, dietary herbal medicine, is also administered to ameliorate gastrointestinal symptoms in PD. Rikkunshi-to is reported to improve erratic GE and reduce the variation of plasma L-dopa level. Recently, intestinal continuous L-dopa administration is expected as the potential solution for L-dopa induced motor fluctuation in advanced PD.

Association of isoniazid-metabolizing enzyme genotypes and isoniazid-induced hepatotoxicity in tuberculosis patients.

BACKGROUND: Isoniazid (INH), a key drug of antituberculosis therapy, is metabolized by arylamine N-acetyltransferase2 (NAT2), cytochrome P450 2E1 (CYP2E1) and glutathione S-transferase (GST). We studied the possible influence of genetic polymorphisms of INH-metabolizing enzymes on serum concentrations of INH and its metabolites, as well as on the incidence of hepatotoxicity. PATIENTS AND METHODS: A total of 144 tuberculosis patients who received antituberculosis treatment were followed prospectively. Their NAT, CYP2E1 and GST genotypes were determined using a polymerase chain reaction with restriction fragment length polymorphism method. Blood samples were collected from the patients and serum concentrations were determined by HPLC. The severity of hepatotoxicity was judged by the increases in either aspartate aminotransferase or alanine aminotransferase levels from the upper limit of the corresponding normal range. RESULTS: Incidence of hepatotoxicity was highest in pulmonary tuberculosis patients with the slow acetylator (SA) phenotype and lowest in those with the rapid acetylator (RA) phenotype, although no clear relationship of genetic polymorphism of INH-metabolizing enzymes on the severity of hepatotoxicity were confirmed. CONCLUSION: The risk of side-effects, such as hepatic disorder, may rise in these patients with an SA phenotype, because of an increase in serum INH concentration. The evidence presented in this study, albeit based on the examination of a low number of patients, suggests that a safe INH dosage for tuberculosis patients with SA phenotype should be less than the dosage which is usually recommended for tuberculosis patients.

Effects of N-acetyltransferase 2 (NAT2), CYP2E1 and Glutathione-S-transferase (GST) genotypes on the serum concentrations of isoniazid and metabolites in tuberculosis patients.

For the purpose of a side-effect monitoring of isoniazid (INH), we investigated the relationship between the genotypes of drug-metabolizing enzymes involved in INH metabolism and the serum concentrations of INH and its metabolites in 129 tuberculosis patients hospitalizing in the National Hospital Organization Chiba-East Hospital. Genotype distributions of N-acetyltransferase 2 (NAT2), CYP2E1*5B, CYP2E1*6, Glutathione-S-transferase (GST) M1 and GST T1 were similar to those already reported in Japanese populations. Acetylating pathway of INH to acetyl isoniazid (AcINH) tended to shift to the hydrolytic pathway generating hydrazine (Hz) with the increase of mutant alleles in NAT2 gene. Serum concentration of Hz was significantly higher in slow acetylators than in rapid acetylators of NAT2. And also, serum concentration of Hz was significantly higher in the group that showed a high concentration of rifampicin (RFP) than in which RFP was not detected. The effect of CYP2E1 gene polymorphisms on the serum concentration of Hz was rarely observed, while that of GST gene polymorphism was observed in intermediate acetylators of NAT2. Hz tended to accumulate in patients with GST M1 null genotype. Therefore, it is conceivable that the risk factors of Hz accumulation are as follows: NAT2 slow acetylator phenotype, high concentration of serum RFP, and GST M1 null genotype. In these cases, we think it's necessary to pay attention to the development of hepatic disorder caused by Hz.