A MATHEMATICAL MODEL FOR PREDICTING THE PERSISTENCE AND EFFICACY OF BACILLUS THURINGIENSIS VAR ISRAELENSIS IN RELATION TO WATER POLLUTION

In a simulated field trial, the bead formulation of Bacillus thuringiensis var israelensis (Bti) was found to be more persistent in moderately polluted as compared to highly polluted water. A mathematical model was built up to study the influence of time (independent variable) on larval reduction (dependent variable) in relation to degree of water pollution. Two predictive models for different grades of water pollution were developed, which estimated that the larval mortality in moderately polluted water was likely to decline by 3.79 as compared to 5.02 on an average, in highly polluted water with each passing day.KEYWORDS: Biocide, Mosquito control, Prediction model     

STUDIES ON THE EFFICACY AND PERSISTENCE OF THE MICROBIAL AGENT BACILLUS SPHAERICUS AGAINST LARVAE OF CULEX PIPIENS PALLENS

This paper evaluates the efficacy of the bacterial larvicide bacillus sphaericus strains BS-10 and C3-41, which are isolated in China, as well as BS2362 against larvae of Culex pipiens pallens in laboratory and under field conditions. The results indicate that C3-41 has the highest toxicity with LC50 at 0.0057 ppm and the bacterial formulations are more effective in light polluted water than in heavy polluted one, but the action of B. sphaericus could persist longer in more polluted water.     

Field Trial of Relative Efficacy of Abate and Bacillus thuringiensis Against Simulium himalayense Larvae (Diptera simulidae)

Simulium himalayense (Diptera simulidae) are known pests which cause severe biting nuisance in North-East region and breed in its fast flowing rivers and rivulets. A field trial was undertaken to control this nuisance with the help of larvicides and to help ascertain relative efficacy of Abate and B thuringiensis against Simulidae. Abate proved to be an effective larvicide for river treatment wherein 0.1 PPM resulted in 100% larval reduction while in small streams, the treatment with Teknar (Bacillus thuringiensis) with 10 PPM for 10 minutes resulted in 80% larval reduction. The results of the present study showed that Abate was more effective in rivers while B thuringiensis proved to be useful in controlling the breeding in the rivulets. An integrated approach using chemical and biological agents is recommended and considered ecologically sound as it does not affect the fish and potability of water.Key Words: Larvicidal control, Simulidae     

Ovicidal and repellent activities of botanical extracts against Culex quinquefasciatus,Aedes aegypti and Anopheles stephensi (Diptera: Culicidae)

Objective

To determine the ovicidal and repellent activities of methanol leaf extract of Ervatamia coronaria (E. coronaria) and Caesalpinia pulcherrima (C. pulcherrima) against Culex quinquefasciatus (Cx. quinquefasciatus), Aedes aegypti (Ae. aegypti) and Anopheles stephensi (An. stephensi).

Methods

The ovicidal activity was determined against three mosquito species at various concentrations ranging from 50-450 ppm under the laboratory conditions. The hatch rates were assessed 48 h after treatment. The repellent efficacy was determined against three mosquito species at three concentrations viz., 1.0, 2.5 and 5.0 mg/cm² under the laboratory conditions.

Results

The crude extract of E. coronaria exerted zero hatchability (100% mortality) at 250, 200 and 150 ppm for Cx. quinquefasciatus, Ae. aegypti and An. stephensi, respectively. The crude extract of C. pulcherrima exerted zero hatchability (100% mortality) at 375, 300 and 225 ppm for Cx. quinquefasciatus, Ae. aegypti and An. Stephensi, respectively. The methanol extract of E. coronaria found to be more repellenct than C. pulcherrima extract. A higher concentration of 5.0 mg/cm² provided 100% protection up to 150, 180 and 210 min against Cx. quinquefasciatus, Ae. aegypti and An. stephensi, respectively. The results clearly showed that repellent activity was dose dependent.

Conclusions

From the results it can be concluded the crude extracts of E. coronaria and C. pulcherrima are an excellent potential for controlling Cx. quinquefasciatus, Ae. aegypti and An. stephensi mosquitoes.     

Larvicidal and repellent potential of Moringa oleifera against malarial vector,Anopheles stephensi Liston (Insecta: Diptera: Culicidae)

Objective

To evaluate the larvicidal and pupicidal potential of the methanolic extracts from Moringa oleifera (M. oleifera) plant seeds against malarial vector Anopheles stephensi (A. stephensi) mosquitoes at different concentrations (20, 40, 60, 80 and 100 ppm).

Methods

M. oleifera was collected from the area of around Bharathiar University, Coimbatore. The dried plant materials were powdered by an electrical blender. From each sample, 100 g of the plant material were extracted with 300 mL of methanol for 8 h in a Soxhlet apparatus. The extracts were evaporated to dryness in rotary vacuum evaporator to yield 122 mg and 110 mg of dark greenish material (residue) from Arcang amara and Ocimum basilicum, respectively. One gram of the each plant residue was dissolved separately in 100 mL of acetone (stock solution) from which different concentrations, i.e., 20, 40, 60, 80 and 100 ppm were prepared.

Results

Larvicidal activity of M. oleifera exhibited in the first to fourth instar larvae of the A. stephensi, and the LC₅₀ and LC₉₀ values were 57.79 ppm and 125.93 ppm for the first instar, 63.90 ppm and 133.07 ppm for the second instar, 72.45 ppm and 139.82 ppm for the third instar, 78.93 ppm and 143.20 ppm for the fourth instar, respectively. During the pupal stage the methanolic extract of M. oleifera showed that the LC₅₀ and LC₉₀ values were 67.77 ppm and 141.00 ppm, respectively.

Conclusions

The present study indicates that the phytochemicals derived from M. oleifera seeds extracts are effective mosquito vector control agents and the plant extracts may be used for further integrated pest management programs.     

In vitro germination and propagation of a threatened medicinal orchid,Cymbidium aloifolium (L.) Sw. through artificial seed

ObjectiveTo study the in vitro germination and plantlet regeneration from artificial seeds of Cymbidium aloifolium (C. aloifolium), a highly threatened medicinal orchid of Nepal.MethodsArtificial seeds were produced in vitro by encapsulation of protocorms with 4% sodium alginate and 0.2 mol/L calcium chloride solution. In vitro germination and plantlet regeneration of the artificial seeds were tested by culturing them on different strength of Murashige and Skoog (MS) liquid media (0.25, 0.5 and 1.0) and MS liquid medium supplemented with 0.5 mg/L benzyl amino purine and 0.5 mg/L naphthalene acetic acid. Freshly produced artificial seeds were stored up to 28 d at 4 ºC. In order to check the viability, storage artificial seeds were treated with five different sterilization techniques (T₁, T₂, T₃, T₄, T₅) and inoculated on full strength (1.0) of MS liquid medium after each 7 d of interval upto 28th days.ResultsThe highest percentage of germination (100%) of artificial seed was obtained on quarter (0.25), half (0.5) and full (1.0) strength of MS liquid medium. Experimentally, full strength of MS liquid medium was more effective for earlier seedling development of C. aloifolium. Artificial seeds were successfully stored at 4 ºC till 28th days. Treatments T₁ and T₂ showed 97.5% viability of storage artificial seeds and hence considered as the most effective sterilization techniques to recover the plant from storage artificial seeds. Plantlets developed from artificial seeds were successfully acclimatized in potting mixture containing cocopeat, litter and sphagnum moss with 85% survival rate.ConclusionsThe present study revealed that artificial seeds are the good alternative explants for in vitro mass propagation and short term conservation of C. aloifolium.     

Behavioural studies of faecal continence in the rat

Background

A behavioural animal model of faecal continence and/or incontinence would be of value in experimental studies of the mechanisms by which sacral neuromodulation can effect continence mechanisms in humans.

Aim

The aim of this behavioural study was to establish whether the rat, an obligate coprophagic species, exhibits patterns of faecal continence.

Methods

Standard rat cages were modified to consist of a food and drink area, a nesting area and an empty latrine area. Three floor pressure pads were connected to hour meters to record the time spent in each area over the course of 4 days. The door to the latrine was open for 2 days and closed for another 2 days to create a physical barrier that could only be surmounted by climbing over a partition.

Results

In the first 2 days, most faecal pellets (74 ± 20 %; p < 0.0001) were deposited in the latrine and this was not changed by door closure (81 ± 13 %). Door closure had no effect per se on pellet output (p = 0.99), nor did it alter the place preference for defaecation (p = 0.17, two factor ANOVA). Rats spent less time in the latrine area accounting for 23 and 13 % of total time before and after the door was closed, respectively. Normal and infrared videography showed that the place preference for pellets was not due to pellet collection for coprophagic purposes.

Conclusions

The rat demonstrates place preference for defaecation and may drop pellets to mark remote boundaries. This simple method may prove useful in future animal studies of neuropathic faecal incontinence and refinement of neuromodulation interventions that lack placebo effects.     

Amide Proton Transfer Magnetic Resonance Imaging of Alzheimer's Disease at 3.0 Tesla: A Preliminary Study

Background:

Amide proton transfer (APT) imaging has recently emerged as an important contrast mechanism for magnetic resonance imaging (MRI) in the field of molecular and cellular imaging. The aim of this study was to evaluate the feasibility of APT imaging to detect cerebral abnormality in patients with Alzheimer''s disease (AD) at 3.0 Tesla.

Methods:

Twenty AD patients (9 men and 11 women; age range, 67–83 years) and 20 age-matched normal controls (11 men and 9 women; age range, 63–82 years) underwent APT and traditional MRI examination on a 3.0 Tesla MRI system. The magnetic resonance ratio asymmetry (MTR_asym) values at 3.5 ppm of bilateral hippocampi (Hc), temporal white matter regions, occipital white matter regions, and cerebral peduncles were measured on oblique axial APT images. MTR_asym (3.5 ppm) values of the cerebral structures between AD patients and control subjects were compared with independent samples t-test. Controlling for age, partial correlation analysis was used to investigate the associations between mini-mental state examination (MMSE) and the various MRI measures among AD patients.

Results:

Compared with normal controls, MTR_asym (3.5 ppm) values of bilateral Hc were significantly increased in AD patients (right 1.24% ± 0.21% vs. 0.83% ± 0.19%, left 1.18% ± 0.18% vs. 0.80%± 0.17%, t = 3.039, 3.328, P = 0.004, 0.002, respectively). MTR_asym (3.5 ppm) values of bilateral Hc were significantly negatively correlated with MMSE (right r = −0.559, P = 0.013; left r = −0.461, P = 0.047).

Conclusions:

Increased MTR_asym (3.5 ppm) values of bilateral Hc in AD patients and its strong correlations with MMSE suggest that APT imaging could potentially provide imaging biomarkers for the noninvasive molecular diagnosis of AD.     

某湖水污染区儿童外周血中性粒细胞核突的观察

观察了某湖水污染区学龄儿童外周血中性粒细胞核突的出现频率，在所观察的三个污染区中，Ｂ、Ｃ两处儿童的核突阳性细胞率显著高于对照区（Ｐ＜０．０１），核突形态以棒状为主，各组儿童的核突阳性细胞率均有明显的性别差异，即男性多于女性（Ｐ＜０．０１），被动吸烟对其核突阳性细胞率有明显的影响。在排除性别、被动吸烟等因素的混杂作用后，Ｂ、Ｃ两处儿童的核突阳性细胞率仍显著高于对照区。提示该湖水污染对当地居民健康有潜在影响。     

Effect of a commercial air ionizer on dust mites Dermatophagoides pteronyssinus and Dermatophagoides farinae (Acari: Pyroglyphidae) in the laboratory

Objective

To investigate the short and long term efficacy of a commercial air ionizer in killing Dermatophagoides pteronyssinus (D. pteronyssinus) and Dermatophagoides farinae (D. farinae) mites.

Methods

The effect of a commercial ionizer on D. pteronyssinus and D. farinae was evaluated in the laboratory, using a specially designed test. Mortality was assessed after 6, 16 and 24 hours for direct exposure and after 24, 36, 48, 60 and 72 hours for exposure in simulated mattress. New batches of mites were used for each exposure time.

Results

LT₅₀ for direct exposure of ionizer was 10 hours for D. pteronyssinus and 18 hours for D. farinae. The LT₅₀ for exposure in simulated mattress was 132 hours or 5.5 days for D. pteronyssinus and 72 hours or 3 days for D. farinae. LT₉₅ for direct exposure of ionizer was 36 hours for D. pteronyssinus and D. farinae. Meanwhile, the LT₉₅ for exposure in simulated mattress was 956 hours or 39.8 days for D. pteronyssinus and 403 hours or 16.8 days for D. farinae.

Conclusions

This study demonstrates the increasing mite mortalities with increasing exposure time of a commercial ionizer and suggests that negative ions produced by an ionizer kill dust mites and can be used to reduce natural mite populations on exposed surfaces such as floors, clothes, curtains, etc. However, there is reduced efficacy on mites inside stuffed materials as in mattresses and furniture.     

IMPACT OF PROPHYLACTIC USE OF COLONY STIMULATING FACTORS ON THE PATTERN OF NEUTROPENIA AND INFECTIONS IN MODERATELY INTENSIVE CHEMOTHERAPY

In this study, colony stimulating factors (CSF) were used to prevent neutropenia during moderately intensive chemotherapy in 26 episodes of chemotherapy (12 of acute lymphoblastic leukaemia (ALL) and 14 patients with other malignancies). CSF was administered in doses of 5 µg/kg of body weight within 24 hours of completion of chemotherapy for 7 days in 6 patients and for 10 days in others. Twenty six age and sex matched patients of ALL were included as controls. In the CSF group, incidence of severe neutropenia (grades 3 and 4) reduced significantly by 42.3 per cent though overall incidence of neutropenia did not differ much. Mean duration of neutropenia reduced by 4 days. Nadir total leucocyte count and absolute neutrophil count were significantly higher. There was no difference in the incidence of anaemia, thrombocytopenia and requirement of blood transfusions. Overall infections were less and incidence of severe infections reduced by 42.3 per cent. The duration of infection and of fever was shortened. Requirement of antibiotics was also reduced. All patients in CSF group recovered from infection, while 1 patient died in the control group. Mean duration of delay in chemotherapy was reduced from 10 days in control group to 3 days in CSF group. CSF administration resulted in an escalation of the cost by 112.24 per cent. However shortened duration of antibiotics, hospitalisation, reduced laboratory expenses compensated it by 66.94 per cent Our study indicates that the prophylactic use of CSF is beneficial and cost effective in moderately intensive chemotherapy with a high incidence of febrile neutropenia. Administration for 10 days appears to be more beneficial than 7 days.KEYWORDS: Chemotherapy, Colony Stimulating Factors, Cost-Benefit Analysis, Neutropenia, Prophylaxis     

Combined Subchronic Toxicity of Bisphenol A and Dibutyl Phthalate on Male Rats

Objective To evaluate the combined subchronic toxicity of bisphenol A(BPA) and dibutyl phthalate(DBP) in male Sprague Dawley(SD) rats.Methods Forty 4‐week‐old male rats weighing 115‐125 g were randomly divided into BPA‐treated,DBP‐treated group,BPA+DBP‐treated and control groups and fed with a soy‐ and alfalfa‐free diet containing 285.4 ppm BPA,285.4 ppm DBP,285.4 ppm BPA plus 285.4 ppm DBP,and a control diet,respectively,for 90 consecutive days.At the end of the study,the animals were sacrificed by exsanguination via the carotid artery under diethyl etherane aesthesia and weighed.Organs,including liver,kidneys,spleen,thymus,heart,brain,and testis underwent pathological examination.The androgen receptor(AR),gonadotropin‐releasing hormone receptor(GNRHR),and progesterone hormone receptor(PR) genes from the hypothalamus were detected by real‐time PCR.The biomedical parameters were analyzed.Results No significant difference was found in food intake,body weight,tissue weight,organ/brain weight ratio,and biomedical parameters among the four groups(P>0.05).However,BPA and DBP up‐regulated AR,PR and GNRHR expression levels in rats and showed a synergistic or an additive effect in the BPA+DBP group.Conclusion The combined subchronic toxicity of BPA and DBP is synergistic or additive in male SD rats.     

硒对大鼠食管癌的阻断作用研究

硒为人体必需的微量元素,实验发现硒可以阻止化学致癌物的诱癌作用。作者用甲基戊基亚硝胺诱发大鼠食管瘤的同时,给大鼠长期饮用含亚硒酸钠的自来水溶液,结果显示亚硒酸钠对大鼠食管粘膜的增生、癌前及癌病变均具有明显的阻断作用。     

SYNERGISTIC ACTION OF IODINE-DEFICIENCY ANDFLUORINE-INTOXICATION ON RAT THYROID

212 Wistar rats were divided randomly into fivegroups, each of which was fed on one of the follow ing regimes: (1) Normal iodine and fluorine; (2) normal iodine, 10 ppm fluorine; (3) normal iodine, 30 ppm fluorine; (4) flow iodine, normal fluorine; (5) low iodine, 10 ppm fluorine. The experiment lasted seven months. The results showed that severe morphologic and functional damage of the thyroid appeared in the rats drinking water containing 30 ppm fluorine, but only slight abnormal ultrastructural changes of thyroid cells appeared in rats drinking water containing 10 ppm fluorine; rats with iodine deFiciency showed proliferative changes of the thy- roid; rats on iodine deficient diet and drinking water containing 10 ppm fluorine showed morphologic and functional damage as well as proliferation. The study suggests that there is synergistic action of iodine-deficiency and fluorine-intoxication on the thy roid.     

Burden of blood transmitted infections in substance users admitted for inpatient treatment in Singapore and the associated factors

INTRODUCTION

There is a paucity of local data on the prevalence of blood transmitted infections (BTIs), such as hepatitis B, hepatitis C and human immunodeficiency virus (HIV) infections, among illicit drug users. This study aimed to examine the prevalence of BTIs among substance-dependent inpatients and identify the factors associated with BTIs.

METHODS

We conducted a retrospective case note analysis of 170 inpatients who had a history of substance dependence and were seen at the National Addictions Management Service, Singapore, between 1 June 2009 and 31 May 2010.

RESULTS

The majority of the 170 inpatients were male (88.2%) and Chinese (58.2%). The mean age of the patients was 43.1 years, and the main drug of abuse was opioids (86.5%). BTIs were found in 70 (41.2%) inpatients; the prevalence of hepatitis B, hepatitis C and HIV infections was 3.7%, 39.6% and 0%, respectively. Lifetime intravenous drug use, but not needle-sharing, was more common among inpatients who were positive for BTIs (p < 0.01). Logistic regression analysis showed that lifetime intravenous drug use (OR 4.3, 95% CI 1.7–10.8, p < 0.01) was the only significant predictor of BTI.

CONCLUSION

41.2% of the substance users seeking help were positive for at least one BTI. Lifetime intravenous drug users were found to be more than four times more likely to have a BTI. Early detection and prevention is essential to improve prognosis.     

几种霉制食品及虾酱的诱变性分析

用沙门氏鼠伤寒杆菌 TM_(677)抗8-吖鸟嘌呤正向突变试验检测腊八豆、豆瓣酱、豆腐乳及虾酱的诱变性,均为阴性。模拟人胃情况进行亚硝化处理后,均显不同程度的诱变性,且呈明显的剂量-诱变性效应关系。所含诱变剂前体的种类较多。但制腊八豆的同种同批黄豆未显诱变性,说明诱变剂前体产生于霉制加工过程。如在亚硝化处理前,加 2800ppm的抗坏血酸,可抑制全部阳性效应。     

Analgesic,antibacterial and central nervous system depressant activities of Albizia procera leaves

ObjectiveTo ascertain analgesic, antibacterial and central nervous system (CNS) depressant activities of ethyl acetate, dichloromethane and carbon tetrachloride fractions of methanol extract of Albizia procera (A. procera) leaves.MethodsLeaves extracts of A. procera were tested for analgesic activity by acetic acid induced and formalin test method in mice. The in vitro antibacterial activity was performed by agar well diffusion method. CNS depressant activity was evaluated by hole cross and open field tests.ResultsAll the extracts at 200 mg/kg exhibited significant (P<0.01) analgesic activity in acetic acid induced and formalin tests method in mice. Analgesic activity of the ethyl acetate fraction was almost same like as standard drug indomethacin in acetic acid induced method. The CNS depressant activity of the extracts at 500 mg/kg was comparable to the positive control diazepam as determined by hole cross and open field test method. The extracts exhibited moderate antimicrobial activity against all the tested microorganisms (Staphylococcus aureus, Bacillus cereus, Pseudomonas aeruginosa, Esherichia coli, Shigella soneii, Shigella boydii) at concentration of 0.8 mg/disc. The measured diameter of zone of inhibition for the extracts was within the range of 7 to 12 mm which was less than the standard kanamycin (16-24 mm).ConclusionsIt is concluded that all the extracts possess potential analgesic and CNS depressants activity. This study also showed that different fractions of methanol extract could be potential sources of new antimicrobial agents.     

足底电击应激时程对大鼠焦虑样行为的影响

目的观察足底电击应激时程对大鼠高架十字迷宫及开场实验焦虑样行为的影响。方法选取成年雄性SD大鼠按照体重分层随机分为对照组和足底电击组,每组12只。足底电击组予以不可逃避性足底电击(0.8 m A,电击10 s,休息20 s,共5 min,1次/d)结合孤养建立大鼠焦虑模型。分别在足底电击7 d及14 d后测高架十字迷宫和开场实验,评估大鼠的焦虑行为。结果 7 d及14 d足底电击后,足底电击组焦虑样行为增加,差异具有显著意义(P0.01),入臂总次数明显低于对照组,运动活性降低。开场实验足底电击组进入中心区次数及中心区逗留时间低于对照组(P0.01),运动总距离、直立次数及理毛次数足底电击组均明显低于对照组(P0.01),运动探索活性降低。比较7天及14天足底电击组行为学结果,可见随着造模天数的增加,大鼠闭臂时间比及闭臂次数比呈现下降趋势(P0.05),焦虑程度降低。开场实验运动总距离、直立次数及理毛次数14 d低于7d,差异具有显著性(P0.05),提示大鼠运动探索行为进一步减少,自我关注度降低,抑郁样行为增加。结论不同时程的足底电击应激导致大鼠焦虑样行为,影响大鼠运动探索活性。随着造模天数的增加,大鼠行为可能从焦虑样向抑郁样改变。足底电击应激焦虑模型造模时程的选择7 d优于14 d。     

N-亚硝基二乙胺(DEN)诱导SD大鼠肝癌模型的研究

目的建立与人类的肝癌发生发展过程相似的动物模型,以便研究肝癌的发生发展过程。方法取体质量120~150 g雄性SD大鼠65只,适应环境1周后随机分为实验组(50只)和对照组(15只),实验组饮用含N-亚硝基二乙(DEN)(浓度为76 ppm)(以下简称DEN)的水连续6周后停药,改自由饮水3周,再继续饮用含DEN(76 ppm)的水至20周。对照组常规自由饮水。结果病理学检查证实DEN可诱发大鼠形成肝癌,14周后成癌率为66.7%(10/15),大鼠肝癌的癌变过程大致可分为肝炎期、肝硬化期和肝癌期三个发展阶段。结论饲以76 ppm剂量DEN可诱发大鼠肝癌模型的建立,可以为我们研究大鼠肝癌的发生发展过程提供可靠的动物模型。