Waterborne parasites and physico-chemical assessment of selected lakes in Malaysia

The objective of this study was to assess the physico-chemical parameters and waterborne parasites in selected recreational lakes from Malaysia. Samples were collected from seven stations of Recreational Lake A (RL-A) and six stations of Recreational Lake B (RL-B). The samples were processed to detect the presence of Giardia spp. and Cryptosporidium spp. using immunomagnetic separation kit, helminth eggs or ova by bright field microscopy and Acanthamoeba spp. by cultivation in non-nutrient agar. Chemical parameters such as ammonia, chlorine, fluoride, nitrate and nitrite and physical parameters such as dissolved oxygen, electrical conductivity, pH, salinity, temperature and total dissolved solid were also measured. Both lakes were freshwater with salinity ranging from 0.05 to 0.09 ppt. Most stations of these lakes were contaminated with Cryptosporidium spp., Giardia spp., Ascaris spp. and hookworm. Schistosoma spp. was found in RL-B only, while Acanthamoeba spp. was found in all stations. Of all sampling sites, station 5 of RL-B is the most contaminated. Linear regression and correlation analysis revealed that Giardia spp. and Schistosoma spp. showed a significant negative correlation with turbidity (p?<?0.01). Based on the preliminary data obtained, it is clearly shown that there is a necessity to implement the detection of waterborne parasites and physico-chemical analysis in Malaysia. Future work on heavy metals (chromium, copper, mercury and zinc) is recommended to enhance the overall water quality monitoring and to take appropriate safety measures to ensure maintenance of good water standards.     

Inhibitory effects of kratom leaf extract (Mitragyna speciosa Korth.) on the rat gastrointestinal tract

Kratom (Mitragyna speciosa Korth.) is an indigenous plant of Thailand used traditionally in folk medicine although it is claimed to cause addiction. It is used to treat diarrhea, however, there is no scientific evidence to support the use. The aim of this study is to investigate the effect of methanolic extract of kratom leaves on the rat gastrointestinal tract. Kratom extract at 50, 100, 200 and 400 mg/kg (p.o.) caused a dose dependent protection against castor oil-induced diarrhea in rats and also inhibited intestinal transit. The antidiarrheal effect was not antagonized by naloxzone. The inhibition of intestinal transit by kratom extract was significantly different from the control when treated with a single dose for 1 day. For longer-term treatments of 15 and 30 days, kratom extract did not decrease the intestinal transit time indicating that adaptation had occurred. Kratom extract at a dose level of 200 and 400 mg/kg for 30 days and morphine at 3 mg/kg (i.p.) caused a decrease in the increment of body weight that was significantly different from the control and kratom extract at lower doses (50 and 100 mg/kg). However it had no effect on the level of plasma cholecystokinin. The results suggested that methanolic kratom extract exhibited its antidiarrheal effect on rat gastrointestinal tract. The effects may occur via pathways in addition to the action on opioid receptors. High does of kratom extract decreased the increment of body weight similar to the effect of morphine.     

Effects of Pituitary Adenylate Cyclase-Activating Polypeptide (PACAP) and Vasoactive Intestinal Polypeptide (VIP) onHormone Secretion from Sheep Pituitary Cells in vitro

Although vasoactive intestinal polypeptide (VIP) is thought to be a prolactin releasing factor, in vivo studies on sheep suggest that it is inactive in this species. Recent studies, based primarily on the rat, suggest that the related pituitary adenylate cyclase-activating polypeptide (PACAP) is also a hypophysiotrophic factor but again in sheep, this peptide has no in vivo effects on hormone secretion despite being a potent activator of adenylate cyclase in vitro. This lack of response to either peptide in vivo in sheep could be due to the low concentration of peptide that reaches the pituitary gland following peripheral injection. In the present study we therefore adopted an alternative approach of evaluating in vitro effects of these peptides on GH, FSH, LH or prolactin secretion from dispersed sheep pituitary cells. In a time-course study, PACAP (1 μmol/l) increased GH concentrations in the culture medium between 1 and 4 h and again at 12 h but had no effect in the 6 and 24 h incubations. Prolactin, LH and FSH were not affected by PACAP. The response to various concentrations of PACAP (1 nmol/l–1 μmol/l) were then evaluated using a 3 h incubation. Again prolactin and LH were not affected by PACAP and there was a small increase in GH concentrations but only at high concentrations of PACAP (0.1 and 1 μmol/l; P<0.05). PACAP also stimulated FSH secretion in cells from some animals although this effect was small. The GH response to PACAP was inhibited by PACAP(6–38), a putative PACAP antagonist, but not by (N-Ac-Tyr¹, D-Arg²)-GHRH(1–29)-NH_2, a GH-releasing hormone (GHRH) antagonist. The cAMP antagonist Rp-cAMPS was unable to block the GH response to PACAP suggesting that cAMP does not mediate the secretory response to this peptide. At incubation times from 1–24 h, VIP (1 μmol/l) had no effects on prolactin, LH or GH secretion and, in a further experiment based on a 3 h incubation, concentrations of VIP from 1 nmol/l–1 μmol/l were again without effect on prolactin concentrations. Interactions between PACAP and gonadotrophin releasing hormone (GnRH), GHRH and dopamine were also investigated. PACAP (1 nmol/l–1 μmol/l) did not affect the gonadotrophin or prolactin responses to GnRH or dopamine respectively. However, at a high concentration (1 μmol/l), PACAP inhibited the GH response to GHRH. In summary, these results show that PACAP causes a modest increase in FSH and GH secretion from sheep pituitary cells but only at concentrations of PACAP that are unlikely to be in the physiological range. The present study confirms that VIP is not a prolactin releasing factor in sheep.     

The effects of extracts from anti-diarrheic Thai medicinal plants on the in vitro growth of the intestinal protozoa parasite: Blastocystis hominis

The activities of n-hexane, dichloromethane and methanol extracts from five anti-diarrheic Thai medicinal plants, Acacia catechu (Fabaceae) resin, Amaranthus spinosus (Amaranthaceae) whole plant, Brucea javanica (Simaroubaceae) seed, Piper longum (Piperaceae) fruit and Quercus infectoria (Fagaceae) nut gall were tested against the in vitro growth of fresh isolates of the intestinal protozoan parasite, Blastocystis hominis. The extracts at concentrations that ranged from 62.5 to 2000 microg/mL, were incubated with several isolates of Blastocystis hominis for 48 h. The activities were classified as killed, inhibited, moderately inhibited and not-inhibited. Dichloromethane and methanol extracts from the Brucea javanica seed and a methanol extract from Quercus infectoria nut gall showed the highest activity. At a concentration of 2000 microg/mL, the three extracts killed 82, 75 and 67% of the Blastocystis hominis samples tested and inhibited 94, 100 and 76% of them, respectively. Metronidazole, used as a reference antiprotozoan drug, at a concentration of 40 microg/mL, killed 97% of the Blastocystis hominis isolates and inhibited all samples tested at concentrations that ranged from 1.25 to 20 microg/mL.     

Young coconut juice, a potential therapeutic agent that could significantly reduce some pathologies associated with Alzheimer's disease: novel findings

Brains from ovariectomised (ovx) rats can display features similar to those observed in menopausal women with Alzheimer's disease (AD), and oestrogen seems to play a key role. Preliminary studies on young coconut juice (YCJ) have reported the presence of oestrogen-like components in it. The aim of the study was to investigate the effects of YCJ on the AD pathological changes in the brains of ovx rats. Rat groups included sham-operated, ovx, ovx+oestradiol benzoate (EB) and ovx+YCJ. Brain sections (4?μm) were taken and were immunostained with β-amyloid (Aβ) 1-42, glial fibrillary acidic protein (GFAP) (an intermediate neurofilament of astrocytes) and Tau-1 antibodies. Aβ 1-42, GFAP and Tau-1 are considered as reliable biomarkers of amyloidosis, astrogliosis and tauopathy (neurofibrillary tangles), respectively, which in turn are characteristic features associated with AD. The serum oestradiol (E2) level was measured using a chemiluminescent immunoassay technique. YCJ restored the serum E2 to levels significantly (P?相似文献   

The neuromuscular blockade produced by pure alkaloid,mitragynine and methanol extract of kratom leaves (Mitragyna speciosa Korth.)

Aim of the study

The effects of pure alkaloid, mitragynine and a methanolic extract of kratom leaves were investigated on neuromuscular junction and compound nerve action potential.

Materials and methods

Wistar rats were killed by cervical dislocation and decapitated. The phrenic nerve–hemidiaphragms, hemidiaphragms and sciatic nerve were isolated.

Results

Kratom methanolic extract present at 0.1–1 mg/mL and mitragynine (0.0156 mg/mL) decreased the muscle twitch on the isolated phrenic nerve–hemidiaphragm and hemidiaphragm preparation. Muscle relaxation caused by kratom extract (1 mg/mL) was greater than the effect of mitragynine. Pancuronium and succinylcholine potentiated the effect of kratom extract. It also had a direct relaxation effect on the hemidiaphragm muscle. The muscle relaxation caused by kratom extract was not antagonized by neostigmine, tetraethylammonium and calcium chloride. High concentrations of kratom extract (10–40 mg/mL) and mitragynine (2 mg/mL) blocked the nerve conduction, amplitude and duration of compound nerve action potential.

Conclusions

The mechanism of action of kratom extract might not act as a competitive antagonist of acetylcholine yet its dominant effect was at the neuromuscular junction and not at the skeletal muscle or somatic nerve.     

The in vitro anti-giardial activity of extracts from plants that are used for self-medication by AIDS patients in southern Thailand

This study evaluated the anti-giardial activity of chloroform, methanol and water extracts of 12 medicinal plants (39 extracts), commonly used as self medication by AIDS patients in southern Thailand. The plant extracts and a standard drug, metronidazole, were incubated with 2×10⁵ trophozoites of Giardia intestinalis per millilitre of growth medium in 96-well tissue culture plates under anaerobic conditions for 24 h. The cultures were examined with an inverted microscope and the minimum inhibitory concentration and the IC₅₀ value for each extract was determined. The chloroform extracts from Alpinia galanga, Boesenbergia pandurata, Eclipta prostrata, Piper betle, Piper chaba, Zingiber zerumbet, and the methanol extracts from B. pandurata and E. prostrata were classified as active, i.e. with an IC₅₀ of <100 g/ml, whereas the chloroform extract from Murraya paniculata was classified as being moderately active. This study shows that extracts from some medicinal plants have potential for use as therapeutic agents against G. intestinalis infections.     

Toxoplasmosis-serological evidence and associated risk factors among pregnant women in southern Thailand

Toxoplasma gondii is an important parasite in pregnant women. This case-controlled study assessed the seroprevalence of toxoplasmosis in 640 pregnant women in southern Thailand and identified their associated risk factors. The overall seroprevalence of toxoplasmosis was 181 (28.3%). Of this, 138 (21.6%) were positive for only anti-Toxoplasma immunoglobulin G (IgG) antibody, 43 (6.7%) were positive for both IgG and IgM antibodies, and none were positive for IgM antibody. Multivariate analysis revealed that increasing age (adjusted odds ratio [OR] = 1.64, 95% confidence interval [CI] = 1.01-2.67), living outside Songkhla province (adjusted OR = 1.56, 95% CI = 1.08-2.24), parity (adjusted OR = 1.65, 95% CI = 1.01-2.68), contact with cats (adjusted OR = 1.70, 95% CI = 1.20-2.43), and drinking of unclean water (adjusted OR = 1.70, 95% CI = 1.08-2.68) were factors associated with Toxoplasma seroprevalence. On the basis of the results obtained, a health surveillance program should be initiated as a primary preventive measure for congenital toxoplasmosis and focus on educating women of the child-bearing age group to avoid contact with cats and to strictly practice personal hygiene.     

The anti-amoebic activity of some medicinal plants used by AIDS patients in southern Thailand

The anti-amoebic activities of chloroform, methanol and water extracts from 12 Thai medicinal plants (39 extracts) commonly used by AIDS patients in southern Thailand were screened, at a concentration of 1,000 μg/ml, against Entamoeba histolytica strain HTH-56:MUTM and strain HM1:IMSS growing in vitro. The extracts were incubated with 2×10⁵ E. histolytica trophozoites/ml of medium at 37°C under anaerobic conditions for 24 h. The cultures were examined with an inverted microscope and scored (1–4) according to the appearance and numbers of the trophozoites. The extracts that caused inhibition were selected and retested using the same conditions but with concentrations that ranged from 31.25 to 1,000 μg/ml using E. histolytica strain HM1:IMSS, and the IC₅₀ values for each extract were calculated. The chloroform extracts from Alpinia galanga (IC₅₀ 55.2 μg/ml), Barleria lupulina (IC₅₀ 78.5 μg/ml), Boesenbergia pandurata (IC₅₀ 45.8 μg/ml), Piper betle (IC₅₀ 91.1 μg/ml) and Piper chaba (IC₅₀ 71.4 μg/ml) and the methanol extract from B. pandurata (IC₅₀ 57.6 μg/ml) were all classified as “active”, i.e. with an IC₅₀ of less than 100 μg/ml, whereas those from Murraya paniculata (IC₅₀ 116.5 μg/ml) and Zingiber zerumbet (IC₅₀ 196.9 μg/ml) were classified as being “moderately active”. The IC₅₀ of a standard drug, metronidazole, was 1.1 μg/ml.