Variants in the CNR1 gene predispose to headache with nausea in the presence of life stress

One of the main effects of the endocannabinoid system in the brain is stress adaptation with presynaptic endocannabinoid receptor 1 (CB1 receptors) playing a major role. In the present study, we investigated whether the effect of the CB1 receptor coding CNR1 gene on migraine and its symptoms is conditional on life stress. In a cross‐sectional European population (n = 2426), recruited from Manchester and Budapest, we used the ID‐Migraine questionnaire for migraine screening, the Life Threatening Experiences questionnaire to measure recent negative life events (RLE), and covered the CNR1 gene with 11 SNPs. The main genetic effects and the CNR1 × RLE interaction with age and sex as covariates were tested. None of the SNPs showed main genetic effects on possible migraine or its symptoms, but 5 SNPs showed nominally significant interaction with RLE on headache with nausea using logistic regression models. The effect of rs806366 remained significant after correction for multiple testing and replicated in the subpopulations. This effect was independent from depression‐ and anxiety‐related phenotypes. In addition, a Bayesian systems‐based analysis demonstrated that in the development of headache with nausea all SNPs were more relevant with higher a posteriori probability in those who experienced recent life stress. In summary, the CNR1 gene in interaction with life stress increased the risk of headache with nausea suggesting a specific pathological mechanism to develop migraine, and indicating that a subgroup of migraine patients, who suffer from life stress triggered migraine with frequent nausea, may benefit from therapies that increase the endocannabinoid tone.     

Biofeedback Treatment for Headache Disorders: A Comprehensive Efficacy Review

The aim of the present review was to critically evaluate the documented evidence regarding the efficacy of biofeedback for the two most prevalent headache conditions––migraine and tension-type headache. Drawing upon two recently published meta-analyses, data from 150 outcome studies, including randomized controlled trials as well as uncontrolled quasi-experimental designs, were screened. Of these, 94 studies were selected for inclusion according to predefined criteria. Meta-analytic integrations were carried out separately for the two conditions of interest. The main results were medium-to-large mean effect sizes for biofeedback in adult migraine and tension-type headache patients. Treatment effects remained stable over an average follow-up period of 14 months, both in completer and intention-to-treat analyses. Headache frequency was the primary outcome variable and showed the largest improvements. Further significant effects were shown for perceived self-efficacy, symptoms of anxiety and depression, and medication consumption. Reduced muscle tension in pain related areas was observed in electromyographic feedback for tension-type headache. Biofeedback was more effective than waiting list and headache monitoring conditions in all cases, while electromyographic feedback for tension-type headache showed additional significant effects over placebo and relaxation therapies. Levels of efficacy (migraine: efficacious, level 4; tension-type headache: efficacious and specific, level 5) and recommendations for future research are provided.

Self-regulatory treatment of headache in the elderly

We examined the utility of various combinations of relaxation, cognitive coping, and feedback in an uncontrolled series of 16 older headache patients (aged 60 to 77) diagnosed as having tension, mixed, or migraine headache. At 1-month follow-up, statistically and clinically significant reductions were observed in both overall headache activity and medication intake; 10 patients (63%) were more than 50% improved in both headache reduction and medication reduction. Female headache suffers were more improved than males. These results are inconsistent with our past findings with geriatric headache sufferers but consistent with other, more recent favorable findings. The efficacy of nondrug treatment for geriatric headache clearly warrants further attention.This research was supported in part by a grant from NINDS, NS-23440.     

EMG-biofeedback reduction of tension headache

The biofeedback literature affirms the therapeutic efficacy of EMG-biofeedback-assisted relaxation for the treatment of tension headache. However, this form of therapy has failed to focus on the role of cognitive variables in the control and perception of tension headache. The present case study provides a prototype treatment combining cognitive behavior-modification procedures with EMG-biofeedback training to treat a subject with chronic tension headache. Phase I, baseline, involved collecting mean EMG and daily headache activity, emphasizing specification of environmental stressors. Phase II, cognitive skills-training, focused on:(1) identifying negative self-statements(cognitions) related to stressors, and(2) training the subject to replace negative self-statements with coping self-instructions. This treatment resulted in a 33% headache reduction over baseline, with no concomitant changes in frontalis EMG. Phase III, EMG-biofeedback training, resulted in a 38% reduction in mean EMG level and a 66% reduction in mean headache activity when compared to baseline. The results suggest the importance of attending to cognitive factors in the treatment of tension headache.This paper was presented at the 6th annual meeting of the Biofeedback Research Society, Monterey, California, 1975.     

Chemical constituents of the rhizomes of Hedychium coronarium and their inhibitory effect on the pro-inflammatory cytokines production LPS-stimulated in bone marrow-derived dendritic cells

The rhizomes of Hedychium coronarium have been used for the treatment of inflammation, skin diseases, headache, and sharp pain due to rheumatism in traditional medicine. From this plant, three new labdane-type diterpenes 1–3, named coronarins G–I as well as seven known 4–10, coronarin D, coronarin D methyl ether, hedyforrestin C, (E)-nerolidol, β-sitosterol, daucosterol, and stigmasterol were isolated. Their chemical structures were elucidated by mass, 1D- and 2D-nuclear magnetic resonance spectroscopy. They were evaluated for inhibitory effects on lipopolysaccharide-stimulated production of pro-inflammatory cytokines in bone marrow-derived dendritic cells. Among of them, compounds 1, 2, and 6 were significant inhibitors of LPS-stimulated TNF-α, IL-6, and IL-12 p40 productions with IC₅₀ ranging from 0.19 ± 0.11 to 10.38 ± 2.34 μM. The remains of compounds showed inactivity or due to cytotoxicity. These results warrant further studies concerning the potential anti-inflammatory benefits of labdane-type diterpenes from H. coronarium.     

Muscle discrimination ability at three muscle sites in three headache groups

The present study examined the ability of three headache groups (migraine, mixed migraine/tension, and tension) to accurately discriminate subjective levels of muscle tension at the forearm flexor, frontalis, and trapezius muscle sites. Discrimination ability was assessed at pre- and posttreatment using a psychophysical method of magnitude production. Results show that the ability to discriminate muscle tension levels at pretreatment varied across the headache groups, with migraineurs being the most accurate (r=.854), followed by the mixed headache group (r=.785), and finally the tension headache group (r=.732). Discrimination ability significantly increased at the posttreatment assessment. A multiple regression analysis showed that pretreatment performance on the muscle discrimination task significantly predicted outcome (r=.75) from relaxation and biofeedback training for migraine patients but not for the mixed or tension headache groups.This research was supported by a grant from NINCDS, NS-15235.     

Characterisation of cell wall polysaccharides, arabinogalactans-proteins (AGPs) and phenolics of Cola nitida, Cola acuminata and Garcinia kola seeds

Many Cola plant species are endemic to West and Central Africa. Cola acuminata and Cola nitida are used as masticatory when fresh, while the dried nuts are used for beverages and pharmaceutical purposes in Europe and North America. Garcinia kola seeds, that serve as a substitute for the true kola nuts, are used in African traditional medicine for the treatment of various diseases, including colic, headache and liver cirrhosis. Seeds extracts of G. kola are also known for their anti-inflammatory, antimicrobial and antiviral properties. To gain information on the chemical properties of the kolas, we have isolated and analyzed cell wall polysaccharides, arabinogalactan-proteins and phenolic substances from the seeds of the three kola species. The sugar composition of cell wall material of C. acuminata, C. nitida and G. kola revealed that Gal (up to 30%), Ara, GalA and Glc as the predominant monosaccharides, representing approximately 90% by mol of the total hydrolysable sugar present in this material. In Ammonium oxalate cell wall fraction, GalA was found to be the major sugar present in all kola species. In the alkali-soluble fraction, there were significant differences in the level of Glc and Gal. The level of Glc was high in C. acuminata and C. nitida while the level of Gal and Xyl were high in C. nitida and G. cola. Isolation and quantification of arabinogalactan-proteins demonstrate that G. kola seeds contained four to eight times more of these proteoglycans than the seeds of the other two species. Finally, analysis of soluble phenolic substances shows that caffeine and catechin were largely represented in C. acumina and C. nitida seeds, with caffeine accounting for 50% of all soluble phenolics. These findings indicate that the three Kola seeds are highly enriched in pectins and proteoglycans and that C. acuminata and C. nitida can be used as a possible source of caffeine and catechin.     

Change Mechanisms Associated with Combined Relaxation/EMG Biofeedback Training for Chronic Tension Headache

Therapeutic mechanisms hypothesized to underlie improvements in tension headache activity achieved with combined relaxation and eleclromyographic (EMG) biofeedback therapy were examined. These therapeutic mechanisms included (1) changes in EMG activity in frontal and trapezii muscles, (2) changes in central pain modulation as indexed by the duration of the second exteroceptive silent period (ES2), and (3) changes in headache locus of control and self-efficacy. Forty-four young adults with chronic tension-type headaches were assigned either to six sessions of relaxation and EMG biofeedback training (N = 30) or to an assessment only control group (N = 14) that required three assessment sessions. Measures of self-efficacy and locus of control were collected at pre- and posttreatment, and ES2 was evaluated at the beginning and end of the first, third, and lost session. EMG was monitored before, during, and following training trials. Relaxation/EMG biofeedback training effectively reduced headache activity: 51.7% of subjects who received relaxation/biofeedback therapy recorded at least a 50% reduction in headache activity following treatment, while controls failed to improve on any measure. Improvements in headache activity in treated subjects were correlated with increases in self-efficacy induced by biofeedback training but not with changes in EMG activity or in ES2 durations. These results provide additional support for the hypothesis that cognitive changes underlie the effectiveness of relaxation and biofeedback therapies, at least in young adult tension-type headache sufferers.     

Time preference of headache attack and chronotype in migraine and tension-type headache

ABSTRACT

Migraine attacks have a time preference of headache attack (TPHA). Chronotype is the propensity for an individual to sleep at a particular time during a 24-h period. However, limited evidence exists regarding the association between TPHA and chronotype in individuals with migraine or tension-type headache (TTH). The aim of the present study is to investigate TPHA and chronotype in individuals with migraine and TTH, which are two of the most common primary headaches. One hundred sixty-nine first-visit migraine and TTH participants were consecutively enrolled. Information on sleep onset time and wake up time on workdays and free days, and TPHA were investigated with a face-to-face interview using a questionnaire booklet. Chronotype was assessed, using the midpoint of sleep on free days, corrected for sleep extension on free days (MSFsc), by subtracting one-half of the average weekly sleep duration. Headache frequency per month, headache intensity, impact of headache, sleep quality, daytime sleepiness, insomnia severity, and mood status were also assessed. Time preference of headache attack was reported for 45.5% and 44.8% of participants with migraine and TTH, respectively. Migraineurs with TPHA had an earlier MSFsc than did migraineurs without TPHA (1:18 a.m. ± 282 min vs. 4:18 a.m. ± 186 min; p = .022). Among migraineurs with TPHA, a later MSFsc was associated with a later preferential time of attack (β = 1.3, 95% confidence interval [CI] = 0.6–2.1, p = .004). A later MSFsc was significantly correlated with a higher headache frequency per month among migraineurs with TPHA (β = 1.9, 95% CI = 0.3–3.4, p = .023), but was not significantly correlated among migraineurs without TPHA (β = 1.4, 95% CI ?1.7–4.4, p = .332). Among TTH participants with TPHA, MSFsc was not significantly associated with a preferential time of attack (β = ?0.2, 95% CI = ?1.0 to 0.6, p = .611). Headache frequency was not associated with MSFsc among TTH participants with TPHA (β = 0.2, 95% CI = ?1.2 to 1.6, p = .792) or among TTH participants without TPHA (β = 0.4, 95% CI = ?0.5 to 1.3, p = .354). In conclusion, approximately one-half of participants with migraine and TTH reported having TPHA. Migraineurs with TPHA had an earlier chronotype than did migraineurs without TPHA. A later chronotype was associated with increased headache frequency and a later time of attack among migraineurs with TPHA. Among participants with TTH, TPHA and headache frequency were not significantly associated with chronotype.     

心脏右向左分流对偏头痛患者临床症状的影响

目的:探讨心脏右向左分流(RLS)对偏头痛患者临床特征是否存在影响,并研究RLS分级与头痛强度之间的关系。方法:选择2016年6月-2018年12月青岛大学附属医院收治的偏头痛患者216例作为偏头痛组,选择于青岛大学附属医院体检的健康志愿者60例作为对照组。216例偏头痛患者根据有无RLS分为有RLS偏头痛组(127例)和无RLS偏头痛组(89例)。有RLS偏头痛患者根据RLS分级将其分为大分流组(n=51)、中分流组(n=11)和小分流组(n=65)。观察对照组与偏头痛组RLS情况,比较有RLS偏头痛组和无RLS偏头痛组患者的一般资料情况,比较大分流组、中分流组和小分流组患者的一般资料情况,采用多因素Logistic回归分析偏头痛患者产生RLS的危险因素。结果:对照组与偏头痛组小分流、中分流患病率比较差异无统计学意义(P0.05),而偏头痛组大分流患病率高于对照组(P0.05)。有RLS偏头痛组患者的视觉先兆、感觉先兆的比例均大于无RLS偏头痛组,头痛初始年龄均小于无RLS偏头痛组,头痛强度均高于无RLS偏头痛组(P0.05),两组患者年龄、性别、吸烟、饮酒、高血压、糖尿病、高血脂、运动先兆、遗传、头痛频率、头痛持续时间比较差异无统计学意义(P0.05)。不同RLS分级的偏头痛患者的视觉先兆、感觉先兆、头痛初始年龄、头痛强度整体比较差异有统计学意义(P0.05)。多因素Logistic回归分析显示,视觉先兆、感觉先兆、头痛初始年龄是偏头痛患者产生RLS的独立危险因素(P0.05)。结论:偏头痛发病年龄较小或有视觉先兆、感觉先兆可能提示偏头痛患者伴有RLS,RLS分级与头痛强度没有关系。     

Temporal associations between weather and headache: analysis by empirical mode decomposition

Background

Patients frequently report that weather changes trigger headache or worsen existing headache symptoms. Recently, the method of empirical mode decomposition (EMD) has been used to delineate temporal relationships in certain diseases, and we applied this technique to identify intrinsic weather components associated with headache incidence data derived from a large-scale epidemiological survey of headache in the Greater Taipei area.

Methodology/Principal Findings

The study sample consisted of 52 randomly selected headache patients. The weather time-series parameters were detrended by the EMD method into a set of embedded oscillatory components, i.e. intrinsic mode functions (IMFs). Multiple linear regression models with forward stepwise methods were used to analyze the temporal associations between weather and headaches. We found no associations between the raw time series of weather variables and headache incidence. For decomposed intrinsic weather IMFs, temperature, sunshine duration, humidity, pressure, and maximal wind speed were associated with headache incidence during the cold period, whereas only maximal wind speed was associated during the warm period. In analyses examining all significant weather variables, IMFs derived from temperature and sunshine duration data accounted for up to 33.3% of the variance in headache incidence during the cold period. The association of headache incidence and weather IMFs in the cold period coincided with the cold fronts.

Conclusions/Significance

Using EMD analysis, we found a significant association between headache and intrinsic weather components, which was not detected by direct comparisons of raw weather data. Contributing weather parameters may vary in different geographic regions and different seasons.     

Relationship between symptoms of temporomandibular disorders and dental status, general health and psychosomatic factors in two cohorts of 70-year-old subjects

Objective: To study the prevalence of symptoms of temporomandibular disorders (TMD) in two cohorts of 70‐year‐old subjects examined 8 years apart and analyse the relationship between such symptoms and dental status, general health and various background factors. Materials and methods: Two cohorts of 70‐year‐old subjects, born in 1922 (n = 422) and 1930 (n = 491) respectively, were examined with an interval of 8 years. A TMD symptom index (0–5) was established on answers to five questions related to TMD symptoms. Results: There were no statistically significant differences between the two cohorts for prevalence of TMD symptoms and TMD index, neither for headache, neck ache, bruxism and chewing ability. TMJ sounds was the most prevalent symptom, 14%, whereas other TMD symptoms had low prevalence. The distribution of the TMD symptom index showed that 81% reported no symptoms, 15% one symptom, 3% two symptoms and 1% three to five symptoms. Single TMD symptoms and the TMD index exhibited significant associations (p < 0.001) with bruxism, headache, neck pain and several general health and psychosomatic factors, but with dental status only in women. Logistic regression showed that bruxism, neck pain, mouth dryness and a number of psychosomatic factors were associated with the TMD index. Conclusions: Besides TMJ sounds (14%), other TMD symptoms were rarely reported by the 70‐year‐old subjects. The TMD index was significantly associated with bruxism and several general health and psychosomatic complaints but with dental status only in women.     

Analysis of variability in vertebral morphology and growth ring counts in two Carcharhinid sharks

Inter- and intra-regional variations in vertebrae morphology and growth increment counts (band counts) were analyzed for two carcharhinid shark species, Carcharhinus plumbeus (n = 10) and C. limbatus (n = 11). Five sequential vertebrae were removed from the cervical region, above the branchial chamber and posterior to the chondrocrainium, and thoracic region, below the first dorsal fin. Dorsal–ventral height, medial–lateral breadth, and caudal–cranial length were measured for each sampled vertebra. Results indicate no significant difference in vertebral morphology within a sampled region of the vertebral column. However, a significant difference in vertebral morphology was noted between regions for both shark species, with thoracic vertebrae consistently larger than cervical vertebrae. A sub-set of three vertebrae was taken from each sampled region of each shark for sectioning and counting of growth increments. Analyses of growth increment counts by two readers indicated no significant difference in band counts within and between sampled regions.     

Separate and combined applications of nontoxigenic Aspergillus flavus and A. parasiticus for biocontrol of aflatoxin in peanuts

A 2-year study was carried out to determine the effect of applying nontoxigenic strains of Aspergillus flavus and A. parasiticus to soil separately and in combination on preharvest aflatoxin contamination of peanuts. A naturally occurring, nontoxigenic strain of A. flavus and a UV-induced mutant of A. parasiticus were applied to peanut soils during the middle of each of two growing seasons using a formulation of conidia-coated hulled barley. In addition to an untreated control, treatments included soil inoculated with nontoxigenic A. flavus only, soil inoculated with nontoxigenic A. parasiticus only, and soil inoculated with a mixture of the two nontoxigenic strains. Plants were exposed to late-season drought conditions that were optimal for aflatoxin contamination. Results from year one showed that significant displacement (70%) of toxigenic A. flavus occurred only in peanuts from plots treated with nontoxigenic A. flavus alone; however, displacement did not result in a statistically significant reduction in the mean aflatoxin concentration in peanuts. In year two, soils were re-inoculated as in year one and all treatments resulted in significant reductions in aflatoxin, averaging 91.6%. Regression analyses showed strong correlations between the presence of nontoxigenic strains in peanuts and aflatoxin reduction. It is concluded that treatment with the nontoxigenic A. flavus strain alone is more effective than the A. parasiticus strain alone and equally as effective as the mixture. The U.S. Government’s right to retain a non-exclusive, royalty-free license in and to any copyright is acknowledged.     

Association study of the oestrogen signalling pathway genes in relation to age at natural menopause

Genetic factors play a significant role in influencing the variation of age at natural menopause (AANM). Estrogen receptor β (ESR2), is an important factor in the mechanism of action of estrogen, while the aromatase gene (CYP19) and the 17-alphahydroxylase gene (CYP17) are involved in the biosynthesis of estrogen. We tested whether polymorphisms of ESR2, CYP19 and CYP17 genes are associated with AANM in Caucasian females. A total of 52 SNPs (17 for ESR2, 28 for CYP19, and 7 for CYP17) were successfully genotyped for 229 Caucasian women having experienced natural menopause. Comprehensive statistical analyses focusing on the association of these genes with AANM were conducted. The effects of age, height and age at menarche on AANM were adjusted when conducting association analyses. We found that six SNPs (2, 6–7, 9, 13 and 16) within ESR2 were not significantly associated with AANM after Bonferroni correction. However, two blocks of ESR2 were associated with AANM. For CYP19, two SNPs (24 and 27) were nominally associated with AANM. No significant association was observed between CYP17 and AANM. Our results suggest that genetic variation in the ESR2 and CYP19 genes may influence the variation in AANM in Caucasian women.     

长白山不同海拔白桦幼苗移栽至同一生境的光合及反射光谱特性

环境是影响植物生理性状的主要因素之一,通过改变植物的生长环境来研究植物生理性状的改变是目前研究植物生理生态的热点,而高海拔地区多样的环境为研究物种适应环境变化提供了良好的实验条件。本研究通过移栽的技术手段,将分布在海拔750 m、海拔1200 m和海拔1400 m的3~5年生白桦幼苗移植到海拔750 m相同的林下环境条件下,将3种白桦移栽幼苗和野生白桦幼苗的光响应参数、光谱反射率以及光谱反射指数进行对比研究,分析移栽初期和移栽一年后植物生理性状的异同,探索白桦幼苗迁入新环境的适应性。研究结果表明:移栽初期,通过对比不同海拔来源的白桦移栽幼苗彼此之间各项生理性状以及与原海拔野生白桦幼苗的生理性状发现,包括最大净光合速率(A_(max))、气孔导度(G_s)、胞间CO_2浓度(C_i)在内的生理性状差异显著(P0.05),幼苗光谱反射指数差异性显著(P0.05)。经过一年的适应,不同海拔来源的白桦幼苗与移栽地海拔750 m野生白桦幼苗的生理性状之间差异不显著(P0.05),幼苗光谱反射指数差异性不显著(P0.05),而与原海拔野生幼苗生理性状之间差异显著(P0.05),幼苗光谱反射指数差异显著(P0.05)。在移栽初期,移栽幼苗的各项生理指标已经因环境的改变而发生变化,但仍保留原海拔野生幼苗的生理特性;移栽一年后,移栽幼苗逐渐适应环境,其相关生理性状发生改变,并趋同于移栽地野生白桦幼苗的生理性状。对比一个生长季前后白桦移栽幼苗生理性状的变化可以发现,白桦作为先锋种植物,在新迁入环境后具有良好的环境适应性,能通过调整生理性状适应新环境。研究对幼苗在林下的演替以及森林的更新具有借鉴意义。     

根系对寒温带冻土区兴安落叶松林土壤碳通量的影响

土壤碳通量是森林生态系统碳循环的重要组成部分,根系对土壤碳通量起着关键作用,研究根系对土壤碳通量的影响对寒温带冻土区温室气体研究有重要意义。以杜香-兴安落叶松林(DXL)、杜鹃-兴安落叶松林(DJL)和苔藓-兴安落叶松林(TXL)为研究对象,通过壕沟法进行断根处理,采用便携式土壤呼吸仪G4301对土壤碳通量进行日动态和月动态变化测定与分析。结果表明:6-11月,断根对DXL和DJL土壤CH₄的吸收起抑制作用,降幅分别为15.16%-54.31%和11.26%-33.84%,对TXL土壤CH₄的排放起促进作用,增幅为19.22%-75.52%;对3种类型兴安落叶松林土壤CO₂的排放均起抑制作用,其中对TXL影响最大,对土壤CO₂降幅为32.29%-87.62%。断根对DXL和TXL土壤CH₄的影响在8月最为显著,增幅分别为-54.31%和75.52%,DJL在11月影响最为显著,降幅为33.84%。断根对3种类型兴安落叶松林土壤CO₂排放的影响在6-11月均达到显著程度,其中在11月最为显著,降幅为54.94%-87.62%。断根对3种类型兴安落叶松林土壤CH₄通量日动态影响差异不显著;而对土壤CO₂通量的影响显著,其中在 14:00-18:00影响最为显著,降幅为31.87%-62.26%。土壤温度和空气温度是根系影响土壤碳通量变化的主要因子,断根处理增强了土壤温度对其日变化和月变化的影响,减弱了空气温度对其日动态的影响。这表明,根系自养产生的土壤碳通量可能在日动态变化中更活跃,而在月动态变化中更稳定。     

Analyses of Two Parasitoids with Convergent Foraging Strategies

We compared the foraging strategies of two key braconid endoparasitoids of the tobacco budworm (Heliothis virescens Fab.), Cardiochiles nigriceps Vier. and Microplitis croceipes Cresson, that differ in host and habitat range but otherwise share comparable, overlapping niches. The most important host-location cues by far for both species were materials associated with damaged plants. Both species demonstrated a significant preference for volatiles released from plants damaged by H. virescens larvae over those released from undamaged tobacco and cotton plants. In choice experiments with damaged tobacco versus cotton, M. croceipes showed a significant preference for cotton plants. In contrast, C. nigriceps preferred damaged tobacco plants. Plant compounds provoked a strong response even when released from systemically induced plants (from which damaged leaves, host, and host by-products were removed). C. nigriceps appears to have a much keener ability to locate hosts over long distances than M. croceipes. This observation may be related to the highly specialized nature of this parasitoid. The possible adaptive significance of the foraging behaviors of these two parasitoids is discussed.     

Precipitating and relieving factors of migraine versus tension type headache

ABSTRACT: BACKGROUND: To determine the differences of precipitating and relieving factors between migraine and tension type headache METHODS: This is a cross sectional study. We retrospectively reviewed the records of 250 migraine patients and 250 patients diagnosed as tension type headache from the specialized headache clinic in Dept. of Neurology, Dhaka Medical College Hospital. Data were collected through a predesigned questionnaire containing information on age, sex, social status and a predetermined list of precipitating and relieving factors. RESULTS: In this study, the female patients predominated (67%). Most of the patients were within 21--30 years age group (58.6%). About 58% of them belonged to middle class families. The common precipitating factors like stress, anxiety, activity, journey, reading, cold and warm were well distributed among both the migraine and tension type headache (TTH) patients. But significant difference was demonstrated for fatigue (p < 0.05), sleep deprivation (p < 0.05), sunlight (p < 0.01) and food (p < 0.05), which were common among migraineurs. In consideration of relieving factors of pain, different maneuvers were commonly tried by migraineurs and significant difference were observed for both analgesic drug and massage (p < 0.05), which relieved migraine headache. But maneuvers like sleep, rest and posture were used by both groups. CONCLUSION: The most frequent precipitating factors for headache appear to be identical for both migraine and TTH patients. Even though some factors like fatigue, sleep deprivation, sunlight and food significantly precipitate migraine and drug, massage are effective maneuver for relieving pain among migrianeurs.     

Symbiotic effectiveness of strains of Rhizobium leguminosarum biovar phaseoli isolated from soils of Rwanda

We have isolated 48 strains of Rhizobium leguminosarum biovar phaseoli from nodules of Phaseolus vulgaris L. cultivated on 32 different soils at 22 various locations in Rwanda, Central Africa. The symbiotic effectiveness of the strains was appraised in the greenhouse by measuring shoots dry matter and total plant nitrogen content after six weeks of growth. Of the strains tested 19%, 58% and 23% were rated very effective, effective and ineffective, respectively. A very significant correlation (r=0.96, P<0.01) was observed between shoots dry matter and total N content. By using the total nitrogen balance method, it was estimated that in the presence of a very effective strain, up to 86% of the N present in the shoots comes from N₂ fixation. No significant correlations were observed between the symbiotic effectiveness of the strains and the pH of the soils from which they originated, the tolerance of the strains to acidity or their ability to produce organic acids. The nine very effective strains selected were highly competitive against two ineffective strains with the two P. vulgaris cultivars Rubona-5 and Kiryumukwe.Contribution no 367, Station de recherches, Agriculture Canada.Contribution no 367, Station de recherches, Agriculture Canada.