bluuebunny/crossref_metadata_2025 huggingface dataset:
An apoplastic mechanism for short‐term effects of rare earth elements at lower concentrations
Authors: SUN Y. , LIU D. L. , YU Z. Q. , ZHANG Q. , BAI J. , SUN D. Y.
Published: June 2003

The short‐term effects of rare earth elements on pollen germination and tube growth were tested. Concentrations of 2.5∼20 µm lanthanum(La3+) or cerium (Ce3+)increased pollen germination and pollen tube growth, whereas concentrations higher than 40 µm La3+ and Ce3+ inhibited this process. The most effective concentration of La3+ needed for promotion shifted from 10 to 40 µm, depending on the Ca2+ concentration in the medium. Calmodulin (CaM) antagonist W7‐agarose and anti‐CaM antibody depressed La3+‐promoted pollen germination and tube growth in a dose‐dependent manner. La3+–CaM complexes (La3+–CaM) increased pollen germination and tube growth more than CaM or La3+ alone. Pertussis toxin (PTX) inhibited La3+‐promoted pollen germination and tube growth. Cholera toxin (CTX) partially recovered the inhibition of the above La3+‐promoted process by the anti‐CaM antibody. Concentrations of 10−7∼10−9 m La3+–CaM increased GTPase activity inside plasma membrane vesicles of the pollen tube, but apo‐CaM or La3+ alone had no positive effects. The results suggest that apoplastic CaM may be involved in the promotion effects of lower concentrations of La3+ on pollen germination and tube growth, and the heterotrimeric G‐protein on the plasma membrane may transduce La3+‐activated CaM signalling. The present studies provide an apoplastic mechanism for short‐term effects of rare earth elements at lower concentrations in the pollen system.
Rapid microalgal metabolism of selenate to volatile dimethylselenide
Authors: NEUMANN P. M. , DE SOUZA M. P. , PICKERING I. J. , TERRY N.
Published: June 2003

An axenically cultured isolate of single‐celled freshwater microalgae (Chlorella sp.) metabolized toxic selenate to volatile dimethylselenide at exceptionally high rates when transferred from mineral‐nutrient solution to water for 24 h. The Se‐volatilization rates were orders of magnitude higher than those similarly measured for wetland macroalgae and higher plants. Ninety percent of 20 µm selenate supplied to the microalgae incubated without nutrients was removed through accumulation and volatilization. Additions of 1 mm sulphate but not nitrate, inhibited Se accumulation and volatilization so that only 1.8% of the supplied selenate was removed. The microalgae cultured in nutrient solution without sulphate showed increased 35S‐sulphate‐transporter activity. Selenium K‐edge X‐ray absorption spectroscopy of selenate‐treated microalgae cultured with or without mineral nutrients, showed that 87% of the selenate accumulated during 24 h was reductively metabolized to intermediate organic compounds such as selenomethionine and selenocystine. This is in complete contrast to higher plants that show very limited reduction of selenate. It appears that high rates of Se accumulation and volatilization by the sulphate‐deprived microalgae resulted from reduced competition with chemically analogous sulphate ions for selenate uptake via up‐regulated sulphate/selenate transporters and rapid reductive metabolism of selenate. Hyper‐volatilization of selenate by microalgal cells may provide a novel detoxification response.
Differential expression of three members of the AMT1 gene family encoding putative high‐affinity NH4+ transporters in roots of Oryza sativa subspecies indica
Authors: KUMAR A. , SILIM S. N. , OKAMOTO M. , SIDDIQI M. Y. , GLASS A. D. M.
Published: June 2003

In order to investigate the molecular basis of high‐affinity ammonium absorption by roots of rice plants (Oryza sativa subspecies indica) the expression patterns of three members of the AMT1 family of genes in rice seedling roots in response to altered nitrogen provision and diurnal changes in irradiance were examined. The 13NH4+ influx and transcript levels of OsAMT1.1 in roots decreased several fold within 48 h when plants acclimated to 10 µm external NH4+ for 3 weeks were transferred to 10 mm NH4+. Likewise when plants acclimated in 10 mm NH4+ were transferred to 10 µm NH4+, there was an equally rapid up‐regulation of OsAMT1.1 and 13NH4+ influx in the roots. Changes in transcript abundance of OsAMT1.2 following these treatments were approximately 50% less than in OsAMT1.1, and changes of OsAMT1.3 expression were even less. By contrast, in response to the diurnal changes of irradiance, root transcript abundance of OsAMT1.3 and 15NH4+ influx increased approximately three‐fold late in the photoperiod, whereas OsAMT1.1 and OsAMT1.2 exhibited only modest changes. The present results suggest that high‐affinity NH4+ influx is differentially regulated at the transcriptional level through the expression of three members of the OsAMT1 family of genes in roots of rice seedlings in response to changes of N status and daily irradiance. In general, these findings are in agreement with earlier observations in Arabidopsis and tomato.
Leaf‐level phenotypic variability and plasticity of invasive Rhododendron ponticum and non‐invasive Ilex aquifolium co‐occurring at two contrasting European sites
Authors: NIINEMETS Ü. , VALLADARES F. , CEULEMANS R.
Published: June 2003

To understand the role of leaf‐level plasticity and variability in species invasiveness, foliar characteristics were studied in relation to seasonal average integrated quantum flux density (Qint) in the understorey evergreen species Rhododendron ponticum and Ilex aquifolium at two sites. A native relict population of R. ponticum was sampled in southern Spain (Mediterranean climate), while an invasive alien population was investigated in Belgium (temperate maritime climate). Ilex aquifolium was native at both sites. Both species exhibited a significant plastic response to Qint in leaf dry mass per unit area, thickness, photosynthetic potentials, and chlorophyll contents at the two sites. However, R. ponticum exhibited a higher photosynthetic nitrogen use efficiency and larger investment of nitrogen in chlorophyll than I. aquifolium. Since leaf nitrogen (N) contents per unit dry mass were lower in R. ponticum, this species formed a larger foliar area with equal photosynthetic potential and light‐harvesting efficiency compared with I. aquifolium. The foliage of R. ponticum was mechanically more resistant with larger density in the Belgian site than in the Spanish site. Mean leaf‐level phenotypic plasticity was larger in the Belgian population of R. ponticum than in the Spanish population of this species and the two populations of I. aquifolium. We suggest that large fractional investments of foliar N in photosynthetic function coupled with a relatively large mean, leaf‐level phenotypic plasticity may provide the primary explanation for the invasive nature and superior performance of R. ponticum at the Belgian site. With alleviation of water limitations from Mediterranean to temperate maritime climates, the invasiveness of R. ponticum may also be enhanced by the increased foliage mechanical resistance observed in the alien populations.
Contrasting strategies for UV‐B screening in sub‐Arctic dwarf shrubs
Authors: SEMERDJIEVA S. I. , SHEFFIELD E. , PHOENIX G. K. , GWYNN‐JONES D. , CALLAGHAN T. V. , JOHNSON G. N.
Published: June 2003

The content and distribution of UV‐absorbing phenolic compounds was investigated in leaves of three species of Vaccinium co‐existing at a site in north Sweden. Vaccinium myrtillus L., Vaccinium vitis‐idaea L., and Vaccinium uliginosum L. exhibit markedly different strategies, in terms of localization and content of leaf phenolics and in their responses to UV‐B enhancement. Plants were exposed to either ambient radiation or to enhancement of UV‐B corresponding to 15% (clear sky) depletion of stratospheric ozone for approximately 10 years prior to commencement of this study. Vaccinium myrtillus contained the highest concentration of methanol‐extractable UV‐B‐absorbing compounds, which was elevated in plants exposed to enhanced UV‐B. Fluorescence and confocal laser scanning microscopy showed that these compounds were distributed throughout the leaf, and were particularly concentrated in chlorophyll‐containing cells. In V. vitis‐idaea, most phenolic compounds were cell wall‐bound and concentrated in the walls of the epidermis; this pool increased in response to UV‐B enhancement. It is suggested that these two plants represent extreme forms of two divergent strategies for UV‐B screening, the different responses possibly being related to leaf longevity in the two species. The response of V. uliginosum was intermediate between the other two, with high concentrations of cell wall‐bound phenolics in the epidermis but with this pool decreasing, and the methanol‐soluble pool tending to increase, after exposure to enhanced UV‐B. One explanation for this response is that this plant is deciduous, like V. myrtillus, but has leaves that are structurally similar to those of V. vitis‐idaea.
Association of Vertical Root‐Pulling Resistance with Root Lodging and Grain Yield in Selected S1 Maize Lines Derived from a Tropical Low‐Nitrogen Population
Authors: Kamara A. Y. , Kling J. G. , Menkir A. , Ibikunle O.
Published: June 2003

Root lodging and poor soil fertility are major constraints to maize production in the Guinea savannah of West Africa. Vertical root‐pulling resistance is an indicator of the rooting characteristics of maize cultivars and could be used to select cultivars which have higher resistance to root lodging, take up nitrogen efficiently and have high yield. Twenty maize breeding lines were evaluated in the southern Guinea savannah of Nigeria for vertical root‐pulling resistance, yield and root lodging in the 2000 and 2001 cropping seasons. There were significant differences amongst the breeding lines for all the characteristics measured. Vertical root‐pulling resistance correlated positively with grain yield (r = 0.71, P < 0.01). There was a moderate negative correlation between vertical root‐pulling resistance and root lodging (r = −0.46, P < 0.05). This suggested that selecting for high root‐pulling resistance will improve grain yield and reduce root lodging. There was no significant association between root lodging and grain yield (r = −0.14, P < 0.22). This was attributed to two factors; weak root systems and high cob weight, both of which caused significant lodging.
Lack of Interaction between Extreme High‐Temperature Events at Vegetative and Reproductive Growth Stages in Wheat
Authors: Wollenweber B. , Porter J. R. , Schellberg J.
Published: June 2003

Increased climatic variability and more frequent episodes of extreme conditions may result in crops being exposed to more than one extreme temperature event in a single growing season and could decrease crop yields to the same extent as changes in mean temperature. The developmental stage of the crop exposed to increased temperatures will determine the severity of possible damage experienced by the plant. It is not known whether or not the damaging effects of heat episodes occurring at different phenological stages are additive. In the present study, the interaction of high‐temperature events applied at the stages of double ridges and anthesis in Triticum aestivum (L.) cv. Chablis was investigated. Biomass accumulation of control plants and that of plants experiencing high temperatures during the double‐ridge stage were similar and were reduced by 40 % when plants were subjected to a heat event at anthesis. Grain number on the main and side tillers declined by 41 %, and individual grain weight declined by 45 % with heat stress applied at the double‐ridge stage and anthesis or at anthesis alone. The harvest index was reduced from 0.53 to 0.33. Nitrogen contents in leaves were reduced by 10 % at the double‐ridge stage and by 25 % at anthesis. The maximum rates of CO2 assimilation increased with heat stress at the double‐ridge stage and higher rates were maintained throughout the growing season. The results clearly indicate that an extreme heat event at the double‐ridge stage does not affect subsequent growth or the response of wheat to heat stress at anthesis.
Faults in Determining Nitrogenase Activity
Authors: Singh G. , Wright D.
Published: June 2003

The effects of three treatments performed before the acetylene reduction assay, i.e. shoot removal, shoot removal plus root shaking, and no disturbance (intact plants), and of the length of the incubation period (10, 30 or 60 min) on nitrogenase activity were investigated in pea (Pisum sativumL.). The shoot removal plus root shaking treatment decreased nitrogenase activity to a greater extent than shoot removal. Nitrogenase activity was significantly higher when measured after a 10‐min incubation period than after a 30‐ or 60‐min incubation period. In another experiment, plants disturbed 15 min before the assay had a higher activity than plants disturbed 75 or 135 min before the assay. Similar results were obtained when activity was expressed as total nitrogenase activity and as specific nitrogenase activity.
The Effect of Seed‐Tuber Physiological Age and Cultivar on Early Potato Production
Authors: Asiedu S. K. , Astatkie T. , Yiridoe E. K.
Published: June 2003

Enhancing physiological aging of seed‐potatoes has the potential to substantially affect production, especially for short‐season growing areas. This study analysed the effect of seed‐tuber age and cultivar, jointly, to identify the combination for optimum early crop production, based on field experiments conducted at two locations in Nova Scotia, Canada. The potato cultivars Superior, AC‐Novachip, Niska, and Yukon Gold were aged by exposing seeds stored at 4 °C to warming periods of 0, 242 (3 weeks), and 484 (6 weeks) day‐degrees, prior to planting. Cultivar and age levels were completely randomized within each location and replicated four times. Harvest periods at 65, 80 and 95 days after planting (DAP) were analysed as an unbalanced split‐plot factorial, with year as a random blocking factor, location as a whole plot treatment, and cultivar and age crossed as subplot treatments. Total yield and marketable yield from Yukon Gold improved with physiological age when harvested early at 65 and 80 DAP, while that from AC‐Novachip improved when aged only 3 weeks. Niska was not affected by age. Overall, AC‐Novachip was consistently better than the remaining cultivars, regardless of age. The best treatment combination that maximized marketable yield was Yukon Gold aged 6 weeks planted at a commercial farm and harvested 95 DAP. For early harvest (65 DAP), however, AC‐Novachip aged 3 weeks and Yukon Gold aged 6 weeks generated the highest yields. Niska and Superior generated lower yield and higher culls.
Crop and Weed Growth in a Sequence of Spring Barley and Winter Wheat Crops Established Together from a Spring Sowing (Relay Cropping)
Authors: Roslon E. , Fogelfors H.
Published: June 2003

A relay cropping system of cereals, whereby winter wheat (Triticum aestivum L.) was undersown in two‐row spring barley (Hordeum distichum L.), was established in a field trial in central Sweden in 1999 and continued until 2000. The purpose of the study was to examine crop and weed responses to different plant densities of the undersown winter crop. Winter wheat was sown at four seed rates (187, 94, 47 and 0 kg ha−1) immediately after the sowing of barley. Barley was harvested in the first autumn after sowing and winter wheat in the second autumn. The grain yield of barley was not affected by the seed rate of wheat, and averaged 4580 kg ha−1. Winter wheat did not vernalize during the first growing season but remained at the vegetative stage. The grain yield of wheat was 1990 kg ha−1 for the lowest and 5610 kg ha−1 for the highest seed rate of wheat. Whilst the undersowing process itself stimulated weed emergence in this experiment, increasing the undersowing seed rate reduced the population of perennial weeds by 40–70 %. In the second growing season, the total biomass of weeds was 66 % higher at the highest seed rate compared with the lowest seed rate.
Self‐reported depressive state can be a predictor of engagement in work by community‐dwelling elderly 2 years later
Authors: Kawamoto Ryuichi , Kajiwara Takeshi , Oka Yuichiro , Takagi Yaemi
Published: June 2003

Background:  Depression is one of the most common medical disorders in elderly community‐dwelling persons. The present study prospectively examined the relationship between depressive state in elderly persons and their engagement in work and/or activities during the subsequent 2 years.

Methods:  The study subjects were 603 persons who were engaged in work/activities at baseline. Their mean age ± standard deviation was 71 ± 5.1 years and 299 (49.6%) were men. The final outcome regarding engagement in work was based on whether they held a job or were engaged in activities, such as farming or gardening, every day.

Results:  At baseline, the mean SDS score was 35.5 ± 8.8 (20–63). The number of people engaged in work after 2 years decreased with increasing intensity of depressive state. Those who were engaged in work after 2 years were younger (P = 0.001), male (P = 0.047), married (P = 0.001), and with better financial conditions (P = 0.048). They were also independently able to fulfil BADL (P = 0.006), did not have a history of stroke (P = 0.040), were not regularly taking medication (P = 0.001) and were not depressed (P = 0.001). After adjustment for these covariates, depressive state was a significant independent explanatory variable, and a moderate to severe depressive state (i.e. SDS score of 48 or more) was significantly associated with less engagement in work compared with an SDS score of 39 or less (odds ratio, 2.35; 95%CI, 1.40–4.59).

Conclusion:  Depressive state is associated with an increased risk of decline in engagement in work.
Association between plasma homocysteine concentrations and asymptomatic cerebral infarction or leukoaraiosis in elderly diabetic patients
Authors: Araki Atsushi , Ito Hideki , Majima Yasuoki , Hosoi Takayuki , Orimo Hajime
Published: June 2003

Background:  The purpose of the present study was to investigate the possible contribution of plasma homocysteine to asymptomatic cerebral infarction (CI) or leukoaraiosis.

Methods:  The relationship between plasma homocysteine concentrations and cerebral lesions was investigated in 233 elderly diabetic patients (mean age: 74 years) who were divided into three groups based on the neurological and brain MR findings: asymptomatic cerebral infarction (CI), symptomatic CI, and a control group with no evidence of cerebrovascular disease. Plasma total homocysteine concentrations were measured by high‐performance liquid chromatography. The C677T polymorphism in the methylene tetrahydrofolate reductase (MTHFR) gene was assessed by PCR‐RFLP. The total score of T2 high‐intensity lesions on the brain MR images was summed from the focal T2 high‐intensity scores in 24 areas of the brain.

Results:  Diabetic patients with asymptomatic or symptomatic CI had significantly higher homocysteine concentrations in plasma than the control group. The plasma homocysteine concentration was more strongly associated with the presence and number of small infarctions or infarction of the putamen, which may explain the association between increased plasma homocysteine concentrations and asymptomatic CI in elderly diabetic patients. In the diabetic patients, high plasma homocysteine concentrations were also significantly associated with high scores of total T2 high‐intensity lesions or focal T2 high‐intensity scores in some periventricular regions. Although there was no significant relationship between the MTHFR TT genotype and CI, a significant association was found between the MTHFR TT genotype and total T2 high‐intensity scores.

Conclusion:  An elevated plasma homocysteine concentration is independently associated with asymptomatic CI and T2 high‐intensity lesions on brain MR images in elderly patients with diabetes mellitus. The association between the MTHFR TT genotype and periventricular T2 high‐intensity lesions, but not with CI, suggests an important effect of C677T MTHFR gene mutation on leukoaraiosis, independent of hyperhomocysteinemia in elderly diabetic patients.
Dressing apraxia in corticobasal degeneration
Authors: Okuda Bungo , Tanaka Harumi , Kawabata Keita , Kodama Norihiko , Tachibana Hisao
Published: June 2003

The present paper considers a patient with corticobasal degeneration and dressing apraxia. A 65‐year‐old woman developed difficulties in housekeeping 3 months prior to admission. Neurological examinations revealed mild dementia and asymmetric parkinsonism; the most conspicuous feature was dressing apraxia with constructive disabilities. Magnetic resonance imaging showed right temporoparietal atrophy. A 3‐D brain perfusion imaging demonstrated a decrease in cerebral blood flow in the right perirolandic and perisylvian regions. These clinical and neuroimaging findings were compatible with corticobasal degeneration. Although various types of apraxia are associated with corticobasal degeneration, dressing apraxia has rarely been reported. Our case indicates that dressing apraxia can manifest as another neuropsychiatric problem in corticobasal degeneration if coexistent movement disorders remain mild early in the stage of the illness.
Effects of aerobic and resistance exercise training on insulin action in the elderly
Authors: Kitamura Itsuko , Takeshima Nobuo , Tokudome Mizuho , Yamanouchi Kunio , Oshida Yoshiharu , Sato Yuzo
Published: June 2003

Background:  Aging is associated with a declining glucose tolerance, which is primarily caused by peripheral insulin resistance, and with a decline in physical activity. The aim of this study was to assess the effect of aerobic and resistance exercise training on insulin action in the elderly.

Methods:  Fourteen healthy male subjects (age: 65–73 years) were enrolled and divided into two exercise groups: resistance training (RT) or a combined aerobic and resistance training (CT). Subjects participated in each training program three times a week for 12 weeks. Before and after the training program, insulin action was determined using the euglycemic clamp technique at insulin infusion rates of 40 (low) or 400 (high) mU/m2 per min. Body composition was measured by dual‐energy X‐ray absorptiometry (DXA).

Results:  Percent fat decreased significantly in both groups. Fat‐free mass (FFM) tended to increase in the RT group (P = 0.054), but not in the CT group. In the CT group, the glucose infusion rate (GIR) increased 16.6% (P < 0.05) at the low insulin infusion rate and 21.7% (P < 0.01) at the high rate. In the RT group, GIR tended to increase at the low insulin infusion rate, but was not statistically significant (P = 0.052) and increased 9.9% (P < 0.05) at the high rate. When calculated per FFM, the increased insulin action persisted in the CT group (P < 0.01), but not in the RT group.

Conclusion:  The combination of aerobic and resistance training is more effective for improving the decreased insulin action in the elderly than resistance training alone.
Comprehensive studies of carotid atherosclerosis
Authors: Kohara Katsuhiko , Tabara Yasuharu , Igase Michiya , Yamamoto Yoshikuni , Jiang Yinong , Nakura Jun , Hiwada Kunio , Miki Tetsuro
Published: June 2003

Carotid atherosclerosis is closely associated with the progression of other atherosclerotic conditions, including ischemic heart disease and cerebral infarction. Evaluation of carotid atherosclerosis is useful as an index of systemic atherosclerosis, and is used as a surrogate endpoint in a number of clinical studies. We have been investigating several risk factors on the progression of atherosclerosis, using the carotid arteries as a window on the arterial system in general.
Less frequent body weight gain in elderly type 2 diabetic patients treated with glimepiride
Authors: Inoue Kaori , Ikegami Hiroshi , Fujisawa Tomomi , Shintani Maki , Kawabata Yumiko , Nojima Koji , Ono Masaya , Nisino Masanori , Itoi‐Babaya Michiko , Babaya Naru , Ogihara Toshio
Published: June 2003

Background:  The purpose of the present paper was to study the effect of a new sulfonylurea, glimepiride, which has an extra‐pancreatic action that improves insulin resistance, on glycemic control and body weight gain in elderly patients with type 2 diabetes mellitus (DM).

Methods:  Thirty‐seven type 2 diabetic patients being treated with either gliclazide or glibenclamide were switched to glimepiride for 6 months and clinical parameters were compared between elderly (≥ 65 years old, n = 9) and non‐elderly (< 65 years old, n = 28) patients.

Results:  There was no significant difference between the two groups in baseline characteristics, or in changes in fasting plasma glucose (FPG) and HbA1c. For body weight change, however, none of the elderly patients (0/9) exhibited an increase, but 9 of 28 (32%) non‐elderly subjects showed body weight gain (P < 0.05).

Conclusions:  Body weight gain with glimepiride treatment is less frequent in elderly patients with type 2 DM than in non‐elderly patients with the disease. These data together with the recent increase in obese elderly patients with diabetes suggest that glimepiride is recommended for treatment of type 2 diabetes in this age group.
Excess risk of early death in the elderly attributable to activities of daily living, mental status and traditional risk factors: The Shibata Elderly Cohort Study with a 20‐year follow up
Authors: Kushiro Wakako , Yokoyama Tetsuji , Date Chigusa , Yoshiike Nobuo , Tanaka Heizo
Published: June 2003

Background: A prospective cohort study with a 20‐year follow‐up was conducted to examine the association of the ability to perform activities of daily living (ADL) and other risk factors with the risk of subsequent all‐cause mortality in an elderly Japanese population.

Methods: Cohort members were 705 men and 964 women aged 65 years and older at the time of the baseline examination in 1976–1977.

Results: Disability in the performance of ADL and other risk factors (i.e. bad self‐rated health, low dementia score, decreased pleasure, low morale, and being prone to tears) were significantly associated with an increased risk of subsequent 20‐year all‐cause mortality. The summary population attributable risks of the level of disability in performance of ADL and other risk factors (25.8%, 17.4%, and 6.2% for the follow‐up periods of 0–5, 0–10, and 0–20 years, respectively) were almost of the same magnitude as those of the selected traditional risk factors of mean blood pressure, triceps skinfold thickness and current smoking (24.0%, 18.5%, and 8.6%, respectively).

Conclusion: The association of both disability in performing ADL and other risk factors with mortality was as great as those of selected traditional risk factors when assessed in terms of both relative risk and population attributable risk.
Vascular and non‐vascular risk factors for deep white matter lesions in community‐dwelling elderly subjects
Authors: Yao Hiroshi , Yuzuriha Takefumi , Koga Hiroshi , Takashima Yuki , Fukuda Kenji , Endo Koichi , Uchino Akira , Ibayashi Setsuro , Uchimura Hideyuki , Fujishima Masatoshi , Iida Mitsuo
Published: June 2003

Background:  Traditional risk factors such as hypertension explain some but not all the risk factors for leukoaraiosis or deep white matter lesions (DWML). A previous study suggested that a lower blood concentration of tryptophan was a unique factor related to DWML and the present study sought to further characterize this aspect as one of the presumed non‐vascular risk factors for DWML in subjects without hypertension.

Methods:  Data from 383 community‐dwelling elderly subjects (121 males, 262 females; mean age, 67.1 years) were analyzed. Participants underwent standardized evaluations including a neurological examination, complete blood chemistry panel, ECG, magnetic resonance imaging (MRI), and plasma amino acid measurements. MRI scans used a 1.0‐tesla superconducting magnet with the spin‐echo technique and fluid‐attenuated inversion‐recovery sequences.

Results:  The MRI study revealed that greater age (odds ratio [OR] 1.94/10 years), hypertension (OR 1.86), higher cholesterol (OR 1.49/mmol/L), and lower plasma tryptophan concentrations (OR 0.71/10 µmol/L) were independent variables related to DWML. When the same logistic model was applied to lacunar infarction on MRI, age, male gender, and hypertension, but not cholesterol or tryptophan, were associated with lacunar infarction. The association between lower plasma tryptophan concentrations and DWML was significant in normotensive subjects, but not in hypertensive patients.

Conclusions:  The results of the MRI study suggest that lower plasma tryptophan concentrations contribute to the development of DWML, especially in subjects without classical vascular risk factors such as hypertension. To plan an effective strategy for preventing DWML, future study is needed to elucidate the mechanism by which lower tryptophan concentrations induce DWML.
In Vivo Modulation of Hippocampal Epileptiform Activity with Radial Electric Fields
Authors: Richardson Kristen A. , Gluckman Bruce J. , Weinstein Steven L. , Glosch Caryn E. , Moon Jessica B. , Gwinn Ryder P. , Gale Karen , Schiff Steven J.
Published: June 2003

Summary:  Purpose: Electric field stimulation can interact with brain activity in a subthreshold manner. Electric fields have been previously adaptively applied to control seizures in vitro. We report the first results from establishing suitable electrode geometries and trajectories, as well as stimulation and recording electronics, to apply this technology in vivo.

Methods: Electric field stimulation was performed in a rat kainic acid injection seizure model. Radial electric fields were generated unilaterally in hippocampus from an axial depth electrode. Both sinusoidal and multiphasic stimuli were applied. Hippocampal activity was recorded bilaterally from tungsten microelectrode pairs. Histologic examination was performed to establish electrode trajectory and characterize lesioning.

Results: Electric field modulation of epileptiform neural activity in phase with the stimulus was observed in five of six sinusoidal and six of six multiphasic waveform experiments. Both excitatory and suppressive modulation were observed in the two experiments with stimulation electrodes most centrally placed within the hippocampus. Distinctive modulation was observed in the period preceding seizure‐onset detection in two of six experiments. Short‐term histologic tissue damage was observed in one of six experiments associated with high unbalanced charge delivery.

Conclusions: We demonstrated in vivo electric field modulation of epileptiform hippocampal activity, suggesting that electric field control of in vivo seizures may be technically feasible. The response to stimulation before seizure could be useful for triggering control systems, and may be a novel approach to define a preseizure state.
Diffusion‐weighted Imaging Abnormalities in the Splenium after Seizures
Authors: Oster Joel , Doherty Colin , Grant P. Ellen , Simon Mirela , Cole Andrew J.
Published: June 2003

Summary:  Purpose: Transient increased T2 signal in the splenium of the corpus callosum after seizures has been reported and sometimes attributed to a postulated toxicity of anticonvulsant medications (AEDs).

Methods: We describe two patients with bitemporal epilepsy.

Results: Transiently increased T2 signal (in one) and decreased apparent diffusion coefficient (ADC) (in both) in the splenium appeared to be related directly to acute seizures.

Conclusions: These cases illustrate an unusual acute postictal imaging finding, highlight involvement of an important commissural pathway, and suggest that seizures per se, and not their treatment, are the cause of transient white‐matter abnormalities in these cases.
Increased Frequency of Interleukin‐1β‐511T Allele in Patients with Temporal Lobe Epilepsy, Hippocampal Sclerosis, and Prolonged Febrile Convulsion
Authors: Kanemoto Kousuke , Kawasaki Jun , Yuasa Shoji , Kumaki Testuo , Tomohiro Oshima , Kaji Ryuji , Nishimura Masataka
Published: June 2003

Summary:  Purpose: To confirm the high frequency of interleukin (IL)‐1β‐511T allele occurrence in patients with temporal lobe epilepsy (TLE) and hippocampal sclerosis (HS), with special attention given to the impact of prolonged febrile convulsions (PFCs) on IL‐1β genotype distribution.

Methods: Patients with evidence of unilateral HS on magnetic resonance (MR) images were chosen as study subjects (TLE+HS; n = 66). Other patients with essentially normal MRI findings or only foreign tissue (TLE without HS; TLE‐HS; n = 64), and those with symptomatic localization‐related epilepsy but without TLE (SLE; n = 89) were selected as disease controls. A single base pair polymorphism at position 2511 in the promoter region of the IL‐1β gene was analyzed.

Results: The distribution of IL‐1β‐511 genotypes as well as allele frequency was significantly different between TLE+HS patients and controls. In contrast, no difference was found between TLE‐HS patients and controls or between SLE patients and controls. Further, in the group of patients with TLE+HS, the frequency of the IL‐1β‐511T allele tended to increase as a function of febrile convulsions [0.531 without either PFC or simple febrile convulsion (SFC); 0.633 with SFC; 0.686 with PFC]. Although no statistically significant difference was noted between patients without PFC and the controls, a χ2 analysis of allele distribution revealed a significant difference between those with PFC and the controls.

Conclusions: PFC proved to be a potent determinant of IL‐1β‐511T allele frequency; thus a discrepancy of PFC incidence should be considered an explanation of recent conflicting results regarding the association between the gene polymorphisms of IL‐1β‐511 and TLE+HS.
Hippocampal Deformation‐based Shape Analysis in Epilepsy and Unilateral Mesial Temporal Sclerosis
Authors: Hogan R. Edward , Bucholz Richard D. , Joshi Sarang
Published: June 2003

Summary:  Purpose: To assess shape changes in patients with mesial temporal sclerosis (MTS) and temporal lobe epilepsy (TLE), by using deformation‐based hippocampal shape analysis.

Methods: We retrospectively reviewed magnetic resonance imaging (MRI) studies in 30 subjects with unilateral MTS (15 right‐sided MTS, 15 left‐sided MTS) and TLE. We defined the “average” hippocampus in the right‐ and left‐MTS groups by generating a mean transformation for the 15 deformation images in each group. Further to quantify the difference between the hippocampi, we coregistered the mean transformation of the involved hippocampus (with MTS) to the contralateral hippocampus, considering the left‐ and right‐MTS groups independently. We generated a color “flame” scale showing degrees of outward and inward deviation of the coregistered hippocampi.

Results: Both the right‐ and left‐MTS groups showed similar shape changes, with maximal inward deformation in the medial and lateral hippocampal head and the hippocampal tail. However, more extensive involvement was seen in the lateral hippocampal body in the right‐MTS group as compared with the left.

Conclusions: Deformation‐based hippocampal shape analysis shows specific regions of hippocampal surface anatomy that are most affected in MTS. This technique may aid in detection of clinically significant anatomic abnormalities of the hippocampus in patients with epilepsy.
Practice Parameter: Temporal Lobe and Localized Neocortical Resections for Epilepsy
Authors: Engel Jerome , Wiebe Samuel , French Jacqueline , Sperling Michael , Williamson Peter , Spencer Dennis , Gumnit Robert , Zahn Catherine , Westbrook Edward , Enos Bruce
Published: June 2003

Summary:  Purpose: To examine evidence for effectiveness of anteromesial temporal lobe and localized neocortical resections for disabling complex partial seizures.

Methods: Systemic review and analysis of the literature since 1990.

Results: One intention‐to‐treat Class I randomized controlled trial of surgery for mesial temporal lobe epilepsy found that 58% of patients randomized to be evaluated for surgical therapy (64% of those who received surgery) were free of disabling seizures and 10 to 15% were unimproved at the end of 1 year, compared with 8% free of disabling seizures in the group randomized to continued medical therapy. There was a significant improvement in quantitative quality‐of‐life scores and a trend toward better social function at the end of 1 year for patients in the surgical group, no surgical mortality, and infrequent morbidity. Twenty‐four Class IV series of temporal lobe resections yielded essentially identical results. There are similar Class IV results for localized neocortical resections; no Class I or II studies are available.

Conclusions: A single Class I study and 24 Class IV studies indicate that the benefits of anteromesial temporal lobe resection for disabling complex partial seizures is greater than continued treatment with antiepileptic drugs, and the risks are at least comparable. For patients who are compromised by such seizures, referral to an epilepsy surgery center should be strongly considered. Further studies are needed to determine if neocortical seizures benefit from surgery, and whether early surgical intervention should be the treatment of choice for certain surgically remediable epileptic syndromes.
Pharyngeal Dysesthesia in Refractory Complex Partial Epilepsy: New Seizure or Adverse Effect of Vagal Nerve Stimulation?
Authors: Akman Cigdem , Riviello James J. , Madsen Joseph R. , Bergin Ann M.
Published: June 2003

Summary:  Sensory symptoms are commonly seen in association with focal epilepsy, but viscerosensory auras, such as pharyngeal dysesthesias, are rarely the main clinical manifestation. With the introduction of vagal nerve stimulation (VNS) for medically refractory epilepsy, viscerosensory symptoms commonly occur as an adverse effect of VNS. Voice alterations (hoarseness or tremulousness), local neck or throat pain, and cough are the most common adverse effects seen during active stimulation (on‐time). Numbness of the throat, neck, or chin, as well as a tingling sensation of the neck and throat is directly related to stimulation intensity. We present a case in which recurrent pharyngeal sensations caused a diagnostic dilemma and in which monitoring the VNS artifact during video/EEG and correlating this with clinical symptoms helped determine the etiology of the recurrent sensory symptoms.
Expression and Cell Distribution of Group I and Group II Metabotropic Glutamate Receptor Subtypes in Taylor‐type Focal Cortical Dysplasia
Authors: Aronica Eleonora , Gorter Jan A. , Jansen Gerard H. , Van Veelen Cees W. M. , Van Rijen Peter C. , Ramkema Marja , Troost Dirk
Published: June 2003

Summary:  Purpose: Focal cortical dysplasia (FCD) is known to be a major cause of intractable epilepsy. The cellular mechanism(s) underlying the epileptogenicity of FCD remain largely unknown. Because recent studies indicate that metabotropic glutamate receptor subtypes (mGluRs) play a role in epileptogenesis, we investigated the expression and cellular distribution pattern of mGluRs in FCD specimens.

Methods: Immunocytochemical expression of group I and group II mGluR subtypes was investigated in 15 specimens of human FCD obtained during epilepsy surgery.

Results: Strong mGluR1α and mGluR5 (group I mGluRs) immunoreactivity (IR) was observed in the majority of FCD specimens in dysplastic as well as in heterotopic neurons. mGluR1α was expressed in a subpopulation of neurons (mainly large dysplastic cells), whereas mGluR5 was represented in a higher percentage of dysplastic neuronal cells. Group II mGluRs (mGluR2/3) IR was observed less frequently than that in group I mGluRs and generally appeared in <10% of the dysplastic neurons. IR for all three mGluR subtypes was observed in balloon cells. mGluR2/3 appeared to be most frequently expressed in glial fibrillary acidic protein (GFAP)‐positive balloon cells (glial type), and mGluR1α, in microtubule‐associated protein (MAP)2‐positive cells (neuronal type). mGluR5 was present in the majority of balloon cells. Occasionally glial mGluR1α IR was observed in bizarre glial cells with di‐ or multinuclei. Reactive astrocytes were intensively stained, mainly with mGluR5 and mGluR2/3.

Conclusions: The cellular distribution of mGluR subtypes, with high expression of mGluR1α and mGluR5 in dysplastic neurons, suggests a possible contribution of group I mGluRs to the intrinsic and high epileptogenicity of dysplastic cortical regions.
Calorie Restriction and Ketogenic Diet Diminish Neuronal Excitability in Rat Dentate Gyrus In Vivo
Authors: Bough Kristopher J. , Schwartzkroin Philip A. , Rho Jong M.
Published: June 2003

Summary:  Purpose: The ketogenic diet (KD) is an effective treatment for intractable epilepsy. However, little is known about its underlying mechanisms.

Methods: In this study, in vivo extracellular field responses to angular bundle stimulation were recorded in the dentate gyrus of Sprague–Dawley rats fed one of three diets: ketogenic calorie‐restricted (KCR), normal calorie‐restricted (NCR), or normal ad libitum (NAL). Input/output curves and paired‐pulse relations were used to assess network excitability. A maximal dentate activation (MDA) protocol was used to measure electrographic seizure threshold and duration.

Results: Animals fed calorie‐restricted (CR) diets exhibited greater paired‐pulse inhibition, an elevated MDA threshold, and an absence of spreading depression‐like events compared with ad libitum‐fed controls. In the MDA model of epileptogenesis, the rate of increase in electrographic seizure duration after repeated stimuli was markedly reduced in KCR‐fed animals compared with NCR‐ and NAL‐fed controls.

Conclusions: These data suggest that CR, by itself, can be anticonvulsant, and treatment with a KCR diet may be both anticonvulsant and antiepileptogenic.
Obstructive Sleep Apnea in a Clinical Series of Adult Epilepsy Patients: Frequency and Features of the Comorbidity
Authors: Manni Raffaele , Terzaghi Michele , Arbasino Carla , Sartori Ivana , Galimberti Carlo Andrea , Tartara Amelia
Published: June 2003

Summary:  Purpose: The aim of this study was to evaluate the rate and features of obstructive sleep apnea (OSA) in adult epilepsy patients.

Methods: Two hundred eighty‐three adult epilepsy patients (137 men; mean age, 33 years; range, 18–70  years) were prospectively screened for OSA by means of a structured interview. Those in whom OSA was clinically suspected were monitored for a full night by using a portable device (Polymesam), and OSA was diagnosed when they had an Apnea/Hypopnea Index greater than five.

Results: Coexistence of OSA with epilepsy was found in 10.2% (15.4% of the male and 5.4% of the female) epilepsy patients investigated. The OSA was mild in 66.6%, moderate in 22.2%, and severe in 11.1% of the cases. The “epilepsy + OSA” patients were older, heavier, more frequently male, and sleepier (p < 0.05) than those with “epilepsy only.” Furthermore, they experienced their first seizure at an older age (p < 0.05).

Conclusions: Systematic investigation reveals that OSA is frequent in epilepsy patients. The major risk factors for OSA in our epilepsy patients were the same as those typically found in the general population. Of the epilepsy‐related factors, older age at onset of seizures appears to be significantly related to comorbidity with OSA (p < 0.05). The presence in epilepsy patients of these features should alert the clinician to the possibility of an underlying OSA.
The Ketogenic Diet: Adolescents Can Do It, Too
Authors: Mady Mackenzie A. , Kossoff Eric H. , McGregor Amy L. , Wheless James W. , Pyzik Paula L. , Freeman John M.
Published: June 2003

Summary: Purpose:To determine both the efficacy of and compliance with the ketogenic diet in the adolescent population.

Methods:A retrospective study of 45 patients, aged 12–19 years, consecutively enrolled in a ketogenic diet program from 1994 to 2002, was performed. Thirty‐seven patients were from The Johns Hopkins Medical Institutions; eight were from The University of Texas at Houston. Charts were reviewed, and patients were contacted by telephone.

Results:Six months after diet initiation, 28 (62%) of 45 remained on the ketogenic diet, with six (21%) of 28 having 50–90% seizure reduction, and eight (29%) of 28 having >90%. At 12 months, 20 (44%) of 45 remained on the diet, with seven (35%) of 20 having 50–90% seizure reduction and six (30%) of 20 achieving >90% efficacy. Only 22% discontinued the diet for perceived restrictiveness. The mean diet duration was 1.2 years. Patients with multiple seizure types did best, whereas gender, prior seizure frequency, diet ratio, and age did not influence outcome. Patients dependent on parents for daily care were more likely to remain on the diet at 6 months, but had less efficacy. Weight loss (60%) and menstrual dysfunction (45% of female subjects) were the most commonly reported side effects.

Conclusions:The ketogenic diet is as well tolerated and efficacious for adolescents with epilepsy as for the general childhood population.
Clinical and Neuroimaging Features of Good and Poor Seizure Control Patients with Mesial Temporal Lobe Epilepsy and Hippocampal Atrophy
Authors: Andrade‐Valença Luciana Patrízia , Valença Marcelo Moraes , Ribeiro Luciana Torres , Matos André Luís Mendes , Sales Letícia Viana , Velasco Tonicarlo Rodrigues , Santos Antônio Carlos , Leite João Pereira
Published: June 2003

Summary:  Purpose: Hippocampal atrophy (HA) and signal changes, detected at magnetic resonance imaging, have been associated with intractable seizures. Such a relation has been established by tertiary centers, where the prevalence of more severe cases tends to be higher. We evaluated the clinical and imaging variables that may have relevance to seizure control in patients with mesial temporal lobe epilepsy (MTLE) and HA.

Methods: MTLE patients from the outpatient clinic of University of São Paulo School of Medicine at Ribeirão Preto were evaluated with protocols for the temporal lobe. Patients were considered to have good seizure control (GC; n = 42) if they had three of fewer seizures per year. Patients with pharmacoresistance and who did not fit the criteria for GC were considered to have poor seizure control (PC; n = 44). We made group comparisons and correlations of clinical data and hippocampal volume (HV) with seizure frequency.

Results: No statistical differences were observed between the GC and PC groups in the following parameters: age at the time of study, age at the time of the initial precipitating injury (IPI) or first epileptic seizure, epilepsy duration and follow‐up, and family history of epilepsy. No differences were found in HV between GC (male, 2.04 ± 0.60 cc; female, 2.00 ± 0.70 cc) and PC (male, 2.26 ± 0.47 cc; female, 2.15 ± 0.48 cc) groups. Regression analysis indicated no correlation between seizure frequency and HV (p = 0.33).

Conclusions:These findings suggest that the intensity of HA does not have a direct correlation with seizure frequency in patients with MTLE with HA and that the detection of HA in MTLE patients does not mean an unequivocal indication of intractability.
Restricted Frontomesial Epileptogenic Focus Generating Dyskinetic Behavior and Laughter
Authors: Chassagnon Serge , Minotti Lorella , Kremer Stephane , Verceuil Laurent , Hoffmann Dominique , Benabid Alim Louis , Kahane Philippe
Published: June 2003

Summary:  Purpose: Substantial data are missing about the anatomic location of frontal regions supporting gelastic seizures.

Methods: We report the results of stereo‐electro‐encep halographic recordings performed over several distinct functional premotor and executive fields in a patient whose seizures were characterized by dyskinetic behavior and ictal laughter, in the absence of cerebral MRI abnormalities.

Results: The epileptogenic zone was circumscribed in the anterior and ventral part of the supplementary motor area and the underlying dorsal cingulate cortex. There were no or little spreading to cortical neighboring areas. The patient is seizure‐free (follow‐up of 27 months) after a stereotactic electric radiofrequency lesion of the epileptogenic focus.

Conclusion: The present data suggest that pericingulate premotor areas are involved in the triggering of the motor component of laughter. In this case, the coexistence of paroxysmal dyskinesias during laughter might reflect the involvement of specific compartment(s) of the basal ganglia.