Uterine relaxant effects of Curcuma aeruginosa Roxb. rhizome extracts

The effects and plausible mechanism of action of Curcuma aeruginosa Roxb. (Zingiberaceae) rhizome chloroform and methanol extracts on the uterine contraction were investigated using isolated uterus strips from estrogen primed rats. The contractile responses were recorded isometrically with a Grass FT03 force transducer connected to a MacLab system. The experiments were carried out on both nonstimulated, agonist- and KCl-stimulated uteri. In the nonstimulated uterus, the two extracts (10–400 μg/ml) had no significant effect. In contrast, in the stimulated uterus, the chloroform and methanol extracts exerted concentration-dependent inhibition of the contractions induced by oxytocin (1 mU/ml), prostaglandin F_2α (PGF_2α, 0.5 μg/ml), ACh (3 × 10⁻⁶ M) and KCl (40 mM) with the IC₅₀ (inhibition of force) of 31.4, 58.59, 56.21 and 29.28 μg/ml; and 57.79, 69.3, 223.8 and 69.19 μg/ml, respectively. Verapamil, the reference L-type calcium channel blocker, exhibited a similar pattern of inhibition with the IC₅₀ of 0.03, 0.25, 0.35 and 0.04 μg/ml. The IC₅₀ of diclofenac against a PGF_2α-induced contraction was 31.36 μg/ml. It is known that the contraction induced by agonists and KCl is mainly due to calcium influx through the voltage-gated L-type calcium channels opened indirectly or directly by agonist–receptor activation and KCl. Thus, it is speculated that the two plant extracts might inhibit uterine contraction by interrupting the influx of Ca²⁺ probably through voltage-gated L-type calcium channels. This possibility was further substantiated by the ability of the extracts to shift the CaCl₂–contraction curves to the right. As the methanol extract also reduced the contraction of oxytocin in Ca²⁺-free EDTA solution; thus, it is suggested that part of its action may be involved with an intracellular mechanism. The effect of the two extracts did not involve the activation of β₂-adrenoceptors since their effects were unaffected by propranolol. Based on the inhibitory effect of the extracts on the oxytocin-induced contraction, it is concluded that the extracts might be useful as tocolytic agents for the prevention of preterm labor. Their effects on the inhibition of PGF_2α-induced contractions also seem useful for the treatment of dysmenorrhea. There are reports by others that the plant rhizome contains β-pinene and sesquiterpenes. In addition, there is evidence that these compounds possess spasmolytic effects in the rat intestine and uterus. Therefore, the uterine relaxant effect of the plant extracts could be due to β-pinene and some sesquiterpene lactones contents. The methanol extract is less potent than the chloroform extract, and this might be due to the lower amount of terpene compounds or different compounds may involve in this action.     

Diploscapter coronata infection in Thailand: report of the first case

A 73-year-old Thai woman living in Mueang District, Saraburi Province, central Thailand presented with numerous hookworm-like nematodes, finally revealed as Diploscapter coronata, by fecal culture. The patient exhibited no significant clinical signs of the gastrointestinal or genitourinary systems, and was generally not ill as a result of this unusual infection. Less commonly, patients have presented with symptoms and signs of Diploscapter coronata infection. However, potentially serious consequences can occur where people have exposure to an environment that has been contaminated with infected feces, or more specifically, infective eggs; such conditions could lead to human infection with Diploscapter coronata worms. This was the first reported occurrence of human Diploscapter coronata infection in Thailand.     

Cysticercosis: IgG-ELISA evaluations of peak1 antigen and <30 kDa antigen of delipidized extract of Taenia solium metacestodes

The antigenicity of ether-delipidized Taenia solium metacestode extract (DLPAg) was investigated by IgG-ELISA. The antigen showed higher antigenicity than that of non-delipidized antigen (NDLPAg). Then the DLPAg was subjected to Sephacryl S-200 gel chromatography and a partially purified antigen (DLPP1Ag) was identified as the promised antigen by IgG-ELISA using 25 sera from cysticercosis cases, 177 cases of 24 heterologous infections, and healthy controls. Sensitivity was 52% and specificity was 91.8% at the cut-off value (X + 7SD), 0.399. Cross-reactivity occurred with 17 cases of eight diseases: cystic echinococcosis (7/11), taeniasis (1/16), gnathostomiasis (2/8), strongyloidiasis (1/12), angiostrongyliasis (1/12), paragonimiasis heterotremus (2/15), opisthorchiasis (1/9) and fascioliasis (2/7). When DLPP1Ag was fractionated through Ultra free centrifugal tube (retained 30 kDa) and Amicon (PM10), MWCOP1Ag (<30-10> kDa) was obtained; the antigen showed better results than DLPP1Ag with 88% sensitivity and 95.6% specificity at the cut-off value (X + 4SD), 0.264. Nine cases of six diseases cross-reacted with this antigen: cystic echinococcosis (2/11), gnathostomiasis (2/8), trichinellosis (2/12), toxocariasis (1/5), schistosomiasis (1/6), and fascioliasis (1/7). MWCOP1Ag gave higher sensitivity than that of DLPP1Ag but some cross-reactivity occurred.     

Effectiveness of trivalent inactivated influenza vaccine among community-dwelling older adults in Thailand: A two-year prospective cohort study

Background

We conducted a two-year prospective cohort study to measure the effectiveness of trivalent inactivated influenza vaccine (IIV3) to prevent laboratory-confirmed influenza among community-dwelling Thai adults aged ≥65?years during 2015–16 and 2016–17 influenza seasons.

Effectiveness of the 2010 and 2011 Southern Hemisphere trivalent inactivated influenza vaccines against hospitalization with influenza‐associated acute respiratory infection among Thai adults aged ≥50 years

Background

Inactivated influenza vaccine (IIV) effectiveness has been evaluated among older adults in high-income countries, but data on IIV effectiveness in low- and middle-income countries remain sparse. We conducted a test-negative case–control analysis to estimate 2010 and 2011 trivalent IIV effectiveness against hospitalization with influenza-associated acute respiratory infection (ARI) among persons aged ≥50 years in rural Thailand.

Methods

During 2010–2011, active surveillance for ARI hospitalization was conducted in two provinces; patients were tested for influenza viruses by real-time RT-PCR. Vaccination status was obtained from vaccine registries. Case and control patients were patients with nasopharyngeal swabs positive and negative for influenza viruses, respectively. Vaccine effectiveness (VE) was estimated for the 6 months after vaccination began. Logistic regression was used to evaluate the association between case status and vaccination while adjusting for age, province, medical conditions, and time.

Results

During 2010–2011, there were 1545 patients with ARI, of whom 279 (18%) were influenza-positive case patients and 1266 (82%) were influenza-negative control patients. Of the 279 case patients, 247 (89%) had influenza A and 32 (11%) had influenza B. Fourteen of 279 (5%) case patients and 108 of 1266 (9%) control patients were vaccinated against influenza. The unadjusted IIV effectiveness against hospitalization with influenza-associated ARI was 43% (95% CI: 0–68%); adjusted VE was 47% (95% CI: 5–71%).

Conclusion

The 2010 and 2011 IIVs were moderately effective against hospitalization with influenza-associated ARI among Thais aged ≥50 years, but IIV coverage was low. Additional efforts are warranted in Thailand to improve IIV uptake in this target group.     

Rifampin markedly decreases plasma concentrations of praziquantel in healthy volunteers

BACKGROUND AND OBJECTIVE: Praziquantel is extensively metabolized by the hepatic cytochrome P450 (CYP) enzymes. The CYP3A isoforms are likely to be major enzymes responsible for praziquantel metabolism. Rifampin (INN, rifampicin), a potent enzyme inducer of CYP-mediated metabolism (especially CYP2C9, CYP2C19, and CYP3A4), is known to markedly decrease plasma concentrations and effects of a number coadministered drugs. The aim of this investigation was to study the possible pharmacokinetic interaction between rifampin and praziquantel. METHODS: An open, randomized, 2-phase crossover design was used in each study of single or multiple doses. In the single-dose study, 10 healthy Thai male volunteers ingested single doses of 40 mg/kg praziquantel alone (phase 1) or after pretreatment with 600 mg of oral rifampin once daily for 5 days (phase 2). In the multiple-dose study, all participants received multiple doses of 25 mg/kg praziquantel alone (phase 1) or after 5-day pretreatment with 600 mg of oral rifampin once daily (phase 2). Plasma concentrations of praziquantel in each phase were determined by the HPLC method. RESULTS: In the single-dose study, rifampin decreased plasma praziquantel concentrations to undetectable levels in 7 of 10 subjects, whereas praziquantel concentrations were reduced by rifampin to undetectable levels in 5 of 10 subjects in the multiple-dose study. In 3 subjects with measurable concentrations in the single-dose study, rifampin significantly decreased the mean maximum plasma concentration (C(max)) and area under the plasma concentration-time curve from 0 to 24 hours [AUC(0-24)] of praziquantel by 81% (P <.05) and 85% (P <.01), respectively, whereas rifampin significantly decreased the mean C(max) and AUC(0-24) of praziquantel by 74% (P <.05) and 80% (P <.01), respectively, in 5 subjects with measurable concentrations in the multiple-dose study. The mean C(max) and AUC(0-24) of praziquantel in subjects whose praziquantel concentrations could not be detected in the single-dose study (7 subjects) after rifampin pretreatment were reduced by approximately 99% (P <.001) and 94% (P <.001), respectively, and in the multiple-dose study (5 subjects), they were reduced by 98% (P <.05) and 89% (P <.01), respectively. CONCLUSIONS: Rifampin greatly decreased plasma concentrations of single and multiple oral doses of praziquantel to levels lower than that of the minimum therapeutic concentration. Because praziquantel and rifampin are widely used in the treatment of liver flukes (Opisthorchis viverrini) and Mycobacterium tuberculosis, respectively, in Thailand and in some other countries in southeast Asia, the possibility of one drug influencing the pharmacokinetics of the other must be considered. Therefore simultaneous use of rifampin and praziquantel must be avoided in medical practice to optimize the therapeutic efficacy of praziquantel.