bluuebunny/crossref_metadata_2025 huggingface dataset:
Reliability of sports related functional tests with emphasis on speed and agility in young athletes
Authors: Alricsson M. , Harms‐Ringdahl K. , Werner S.
Published: March 2003

The aim of the present investigation was to test the reliability of two sports related functional tests, a speed test (slalom‐test) and an agility test (hurdle‐test). Eleven athletes aged 11 years (8 boys, 3 girls) participated voluntarily in the study. All subjects completed four different test sessions for both the slalom‐test and the hurdle‐test using six standard track hurdles placed at 2‐m intervals along a 12‐m length of track. There were no significant differences between testing sessions for either the slalom‐test (P=0.99) or the hurdle‐test (P=0.96), showing no systematic variation between test times. The intraclass correlation coefficients were 0.96 and 0.90 respectively, indicating a good reliability. We conclude that the slalom‐test and the hurdle‐test are reliable sports related functional tests for measuring speed and agility in groups of young athletic individuals.
Effects of 12‐week shooting training and mode of feedback on shooting scores among novice shooters
Authors: Viitasalo J. T. , Era P. , Konttinen N. , Mononen H. , Mononen K. , Norvapalo K.
Published: March 2003

The mode of feedback has been shown to have an effect on motor skill learning. This study investigated effects of an intensive 12‐week shooting training period, and of the mode of feedback on scores in standing and running target shooting among 30 novices with limited shooting experience. They were divided into one control (no training) and three training groups. One out of the three training groups received only KR (knowledge of results) while the two other groups received KR+KP (knowledge of performance). One of the KR+KP groups received additional visual feedback (FB‐II group), which included videos, graphic and written materials about kinematic and kinetic characteristics of their respective shooting techniques compared to performance of international level shooters. Each training group improved their scores in the running target shooting. There were no significant differences between the three training groups in improvements of sum scores (performance outcome). The current study showed that among novice shooters both KR alone and KR+KP improved running target shooting outcome, and that KR and KP together did not lead to a significantly better shooting performance than KR alone.
The relationships between physical activity, health status and psychological well‐being of fertility‐aged women
Authors: Kull M
Published: March 2003

The purpose of this investigation was to measure the association between leisure time physical activity and health status, mental health and depression. The participants were women aged 18–45. The data were collected using questionnaires that were mailed to 1200 women. The response rate was 55%. The questionnaire contained three instruments: the General Health Questionnaire (GHQ), the Health Questionnaire for Adults, and the Beck Depression Inventory (BDI). The results showed that 52.8% of the sample were physically inactive. Physically active women experienced better mental health (P < 0.05), less depression (P < 0.05) and they had better general health status (P < 0.005). Differences in the emotional state (GHQ score) and depression (BDI score) between active (participating in exercise 3 or 1–2 times a week) and inactive women were significant (P < 0.05). Even a low level of physical activity (1–2 times per week) was positively related to women's mental health (P < 0.05).
Reproducibility of repeated measurements on healthy skin with Minolta Chromameter CR‐300
Authors: Kerckhove Eric , Staes Filip , Flour Mieke , Stappaerts Karel , Boeckx Willy
Published: March 2003

Background/aims: In this report the reproducibility of measurements with the Minolta Chromameter CR‐300 on healthy skin was investigated.

Methods: Intra‐ and inter‐rater reproducibility, reproducibility with two instruments and repeated measurements with a 1 week time lapse were examined on healthy skin of 30 volunteers by means of intra‐class correlation coefficients (ICC) and standard error of measurements (SEM).

Results: Results showed excellent values for ICC in all the four conditions.

Conclusions: On the basis of these results we concluded that the instrument provides reliable information and can be used in comparative clinical trials.
Impact of stress of marital dissolution on skin barrier recovery: tape stripping and measurement of trans‐epidermal water loss (TEWL)
Authors: Muizzuddin Neelam , Matsui Mary S. , Marenus Kenneth D. , Maes Daniel H.
Published: March 2003

Background: Psychological stress of marital disruption is associated with significant increases in a variety of psychological and physical disorders. The effect of stress on the immune system is well documented and skin disorders have been reported to exacerbate during stressful situations. This study was designed to observe the effects of stress on skin barrier strength and recovery. Twenty‐eight healthy females age 21–45 who were in the process of marital separation were tested for skin barrier strength and recovery. The panel was chosen on the basis of the intensity of self perceived stress. The control group was an age‐matched group of self perceived ‘happy’ subjects. Servomed evaporimeter was used to measure trans‐epidermal water loss (TEWL) from cheek area of the face, before and after removing stratum corneum layers with tape strippings. Skin barrier strength was defined as the number of tape strippings required to disrupt skin barrier, which is a TEWL of 18 g/m2/h or more. Barrier recovery was denoted by the level of TEWL, 3 h and 24 h after barrier disruption.

Results: There was no correlation between the degree of stress and barrier strength. However, individuals with high stress recovered slower than the individuals with low stress after 3 h (R = 0.64) and 24 h (R = 0.74).

Conclusions: Psychological stress of marital dissolution does not appear to change skin barrier strength but has a negative impact on skin barrier recovery.
Analysis of skin line pattern for lesion classification
Authors: She Zhishun , Fish Peter J.
Published: March 2003

Background/purpose: It has been observed that skin patterning tends to be disrupted by malignant but not by benign skin lesions. This suggests that measurements of skin pattern disruption on simply captured white light optical skin images could be a useful contribution to a diagnostic feature set. Previous work using a measurement of line strength by a consistent high‐value profiling technique followed by local variance measurement or a region agglomerative classifier to measure skin line pattern disruption was extremely promising but computationally intensive, suggesting that the idea of measuring skin pattern disruption was useful but a simpler method was required.

Methods: The skin pattern was extracted by high‐pass filtration and enhanced by adaptive anisotropic (spatial variant) filtering which smoothes along skin lines but not across them. The skin line main direction and direction variance were estimated using a local image gradient matrix and the difference of these measures across the lesion image boundary was used as a lesion classifier.

Results: A set of images of malignant melanoma and benign naevi were processed as above and the scatter plot of results in a two‐dimensional feature (line direction and line variation difference) space showed excellent separation of benign and malignant lesions. An ROC plot enclosed an area of 0.88.

Conclusions: The experimental results showed that the local line direction and the local line variation were promising features for distinguishing malignant melanoma from benign lesion and the methods used were effective and computationally low‐cost.
Folding of Viral Envelope Glycoproteins in the Endoplasmic Reticulum
Authors: Braakman Ineke , Van Anken Eelco
Published: March 2003

Viral glycoproteins fold and oligomerize in the endoplasmic reticulum of the host cell. They employ the cellular machinery and receive assistance from cellular folding factors. During the folding process, they are retained in the compartment and their structural quality is checked by the quality control system of the endoplasmic reticulum. A special characteristic that distinguishes viral fusion proteins from most cellular proteins is the extensive conformational change they undergo during fusion of the viral and cellular membrane. Many viral proteins fold in conjunction with and dependent on a viral partner protein, sometimes even synthesized from the same mRNA. Relevant for folding is that viral glycoproteins from the same or related virus families may consist of overlapping sets of domain modules. The consequences of these features for viral protein folding are at the heart of this review.
The Class C Vps Complex Functions at Multiple Stages of the Vacuolar Transport Pathway
Authors: Peterson Michael R. , Emr Scott D.
Published: March 2003

The Class C Vps complex, consisting of Vps11, Vps16, Vps18, and Vps33, is required for SNARE‐mediated membrane fusion at the lysosome‐like yeast vacuole. However, Class C vps mutants display more severe and pleiotropic phenotypes than mutants specifically defective in endosome‐to‐vacuole transport, suggesting that there are additional functions for the Class C Vps complex. A SNARE double mutant which is defective for both Golgi‐to‐endosome and endosome‐to‐vacuole trafficking replicates many of the phenotypes observed in Class C vps mutants. We show that genetic interactions exist between Class C vps alleles and alleles of the Class D vps group, which are defective in the docking and fusion of Golgi‐derived vesicles at the endosome. Moreover, the Class D protein Vac1 was found to physically bind to the Class C Vps complex through a direct association with Vps11. Finally, using a random mutagenic screen, a temperature‐conditional allele which shares many of the phenotypes of mutants which are selectively defective in Golgi‐to‐endosome trafficking was isolated (vps11–3ts). Collectively, these results indicate that the Class C Vps complex plays essential roles in the processes of membrane docking and fusion at both the Golgi‐to‐endosome and endosome‐to‐vacuole stages of transport.
Apo AI/ABCA1‐Dependent and HDL3‐Mediated Lipid Efflux from Compositionally Distinct Cholesterol‐Based Microdomains
Authors: Drobnik Wolfgang , Borsukova Hana , Böttcher Alfred , Pfeiffer Alexandra , Liebisch Gerhard , Schütz Gerhard J. , Schindler Hansgeorg , Schmitz Gerd
Published: March 2003

We have investigated whether a raft heterogeneity exists in human monocyte‐derived macrophages and fibroblasts and whether these microdomains are modulated by lipid efflux. Triton X‐100 (Triton) or Lubrol WX (Lubrol) detergent‐resistant membranes from cholesterol‐loaded monocytes were associated with the following findings: (i) Lubrol‐DRM contained most of the cellular cholesterol and at least 75% of Triton‐detergent‐resistant membranes. (ii) ‘Lubrol rafts’, defined by their solubility in Triton but insolubility in Lubrol, were enriched in unsaturated phosphatidylcholine and showed a lower cholesterol to choline‐phospholipid ratio compared to Triton rafts. (iii) CD14 and CD55 were recovered in Triton‐ and Lubrol‐detergent‐resistant membranes, whereas CD11b was found exclusively in Triton DRM. ABCA1 implicated in apo AI‐mediated lipid efflux and CDC42 were partially localized in Lubrol‐ but not in Triton‐detergent‐resistant membranes. (iv) Apo AI preferentially depleted cholesterol and choline‐phospholipids from Lubrol rafts, whereas HDL3 additionally decreased the cholesterol content of Triton rafts. In fibroblasts, neither ABCA1 nor CDC42 was found in Lubrol rafts, and both apo AI and HDL3 reduced the lipid content in Lubrol‐ as well as in Triton‐detergent‐resistant membranes. In summary, we provide evidence for the existence of compositionally distinct membrane microdomains in human cells and their modulation by apo AI/ABCA1‐dependent and HDL3‐mediated lipid efflux.
Protein Dislocation from the Endoplasmic Reticulum – Pulling Out the Suspect
Authors: Jarosch Ernst , Geiss‐Friedlander Ruth , Meusser Birgit , Walter Jan , Sommer Thomas
Published: March 2003

Proteins that fail to fold properly as well as constitutive or regulated short‐lived proteins of the endoplasmic reticulum are subjected to proteolysis by cytosolic 26S proteasomes. This process is known as endoplasmic reticulum‐associated protein degradation. In order to become accessible to the proteasome of this system substrates must first be retrogradely transported from the endoplasmic reticulum into the cytosol, in a process termed dislocation. This export step seems to be accompanied by polyubiquitination of such molecules. Surprisingly, protein dislocation from the endoplasmic reticulum seems to require at least some components that mediate import into this compartment. However, protein import and export display differences in the mechanism that provides the driving force and ensures directionality. Of special interest is the cytoplasmic Cdc48p/Npl4p/Ufd1p complex, which is required for the degradation of various endoplasmic reticulum‐associated protein degradation substrates and seems to function in a step after polyubiquitination but before proteasomal digestion. In this review, we will summarize our knowledge on protein export during endoplasmic reticulum‐associated protein degradation and discuss the possible function of certain components involved in this process.
Regulation of Peptidergic Vesicle Mobility by Secretagogues
Authors: Washburn C. L. , Bean J. E. , Silverman M. A. , Pellegrino M. J. , Yates P. A. , Allen R. G.
Published: March 2003

Neuropeptides are released into the extracellular space from large secretory granules. In order to reach their release sites, these granules are translocated on microtubules and thought to interact with filamentous actin as they approach the cell membrane. We have used a green fluorescent protein‐tagged neuropeptide prohormone (prepro‐orphanin FQ) to visualize vesicle trafficking dynamics in NS20Y cells and cultures of primary hippocampal neurons. We found that the majority of secretory granules were mobile and accumulated at both the tips of neurites as well as other apparently specialized cellular sites. We also used live‐cell imaging to test the notion that peptidergic vesicle mobility was regulated by secretagogues. We show that treatment with forskolin appeared to increase vesicle rates of speed, while depolarization with high K+ had no effect, even though both treatments stimulated neuropeptide secretion. In cultured hippocampal neurons the green fluorescent protein‐tagged secretory vesicles were routed to both dendrites and axons, indicating that peptidergic vesicle transport was not polarized. Basal peptidergic vesicle mobility rates in hippocampal neurons were the same as those in NS20Y cells. Taken together, these studies suggest that secretory vesicle mobility is regulated by specific classes of secretagogues and that neuropeptide containing secretory vesicles may be released from dendritic structures.
Iron and vitamin deficiencies, endocrine and immune status in patients with primary Sjögren's syndrome
Authors: Lundström IMC , Lindström FD
Published: March 2003

OBJECTIVES: To study the prevalence of iron and vitamin deficiencies, endocrine disorders and immunological parameters in patients with primary Sjögren's syndrome (1°SS).

DESIGN AND SUBJECTS: At the time of the establishment of the diagnosis of 1°SS in 43 consecutive patients, a clinical examination including haematological analyses was performed. The patients' medical records were also reviewed.

SETTING: Patients referred for diagnosis to The University Hospital, Linköping, a secondary or tertiary referral hospital serving the middle part of southern Sweden.

RESULTS: In total, current or previously treated iron and vitamin deficiencies were registered for 63% of the 1°SS patients (iron 51%, vitamin B12 25%, folate 9%). Current low ferritin was noted in 24%, low iron saturation in 37%, decreased vitamin B12 in 13% and folate in 9%. Thyroid disease was found in a total of 33% and 30% had had autoimmune thyroiditis. Three patients (7%) had verified diabetes mellitus. Erythrocyte sedimentation rate (ESR) was raised in 65% of the patients and 84% had a polyclonal increase of Ig. Rheumatoid factor (RF) was detected in 85%, antinuclear antibody (ANA) in 74%, anti‐SS‐A in 88% and anti‐SS‐B in 73% of the patients.

CONCLUSION: Iron and vitamin deficiencies and thyroid diseases are common in patients with 1°SS. Since these disorders often are treatable and may affect the patients' distress as well as their immune and exocrine function, an active, recurrent search for deficiencies, endocrine diseases and other frequently recorded disorders is recommended.
Therapeutic management of HIV
Authors: Johnson D
Published: March 2003

Highly active antiretroviral therapy (HAART) has been used to treat HIV for several years with a reduction in mortality and morbidity. However, some patients fail to achieve complete viral suppression. Durability of therapy cannot be guaranteed and cross‐resistance may arise, making second‐line therapy a complex issue. Toxicity and pharmacokinetic interactions with other drugs may complicate long‐term efficacy of regimens. The reduction of viral burden can prevent progressive immunodeficiency and may decrease the risk of selecting resistant viruses. Triple therapy with a protease inhibitor showed a decrease in morbidity, mortality and durability, but protease‐sparing therapies might yield fewer side‐effects. Lipid‐related toxicity of protease inhibitors has resulted in the use of non‐nucleoside reverse transcriptase inhibitors (NNRTI) in HAART. However, a single mutation for an NNRTI can confer cross‐class resistance that limits further options for second‐line therapy. When choosing HAART it is crucial to achieve durability and to structure doses to suit the patient's lifestyle, and it is important for patients to initiate therapy when they are ready. The decision to change drug regimens following treatment failure or rebound will depend on the initial choice of HAART. Viral load reduction occurs rapidly in most patients on HAART but immune reconstitution is slow and occurs almost unaided. Therefore prophylaxis against opportunistic infections should not be stopped prematurely.
Progress in HIV vaccine research
Authors: Van Der Ryst E
Published: March 2003

The relentless expansion of the HIV pandemic has demonstrated that the need for a vaccine is desperate. However, the development of an effective vaccine against HIV is a formidable challenge. It is likely that a successful vaccine will have to induce an immune response consisting of not only neutralizing antibodies targeted to conserved epitopes of the viral envelope and cytotoxic T‐lymphocytes targeted to a variety of viral antigens, but also local mucosal immunity. Furthermore, a vaccine should induce broad‐spectrum immunity covering all HIV subtypes. It is unlikely that a single vaccine will achieve all this, and a combination of vaccines will probably be necessary. Although no efficacious HIV vaccine is available yet, definite progress has been made. It was demonstrated that chimpanzees could be protected from both cell‐free and cell‐associated HIV challenge. Protection from mucosal challenge was also demonstrated in several studies and limited cross‐protection between HIV subtypes was observed in several animal models. In spite of these successes, much remains to be done. Prototype vaccines studied to date have only induced short‐lived immune responses and elicited no antibodies able to neutralize clinical isolates of HIV‐1. Novel ways of producing HIV‐1 envelope antigens may lead to improved antibody responses and raise the chances of a vaccine inducing long‐term protective immunity.
Oral lichen planus: a preliminary clinical study on treatment with tazarotene
Authors: Petruzzi M , De Benedittis M , Grassi R , Cassano N , Vena G , Serpico R
Published: March 2003

OBJECTIVE: The rationale for using tazarotene in oral lichen planus (OLP) is its regulatory action on the growth and differentiation of keratinocytes and on inflammation. This randomized, placebo‐controlled study addresses evaluation of the effects of topic tazarotene in the treatment of OLP.

DESIGN: The degree of lesions before and after treatment scored by a 6‐score scale in six cases treated with tazarotene was statistically compared with those of six controls treated with placebo.

SUBJECTS: Twelve patients with hyperkeratosic OLP were randomly allocated to treatment with tazarotene gel 0.1% b.i.d. or with placebo for eight consecutive weeks.

METHODS: The statistical comparison was executed by means of Wilcoxon analysis for paired data.

RESULTS: Patients treated with tazarotene presented a significant reduction of their lesions as compared with the control group. Among transitory side‐effects, burning sensation and taste abnormalities were observed.

CONCLUSION: Topical tazarotene may be a valuable therapeutic tool in the treatment of hyperkeratotic OLP.
Periodontal diseases and HIV infection
Authors: Robinson PG , Adegboye A , Rowland RW , Yeung S , Johnson NW
Published: March 2003

The workshop considered six related questions about periodontal changes seen in HIV infection. 1) To what extent are specific periodontal changes associated with HIV? 2) Are conventional periodontal diseases modified by HIV infection? The changes associated with HIV appear to be modified presentations of conventional diseases. Research should identify initiation and progression factors for necrotizing diseases. 3) What is the role of geography and transmission groups? These questions cannot be answered without greater standardisation of research methods. 4) Has the epidemiology of these changes changed with the advent of new therapies? The data required to answer this question should be available soon but this question is irrelevant to the vast majority of people with HIV. 5) What pathogens are involved in periodontal changes seen in HIV infection? The role of Candida spp. and other potential pathogens requires further investigation. 6) What management protocols are suitable for the periodontal diseases? The significance of periodontal diseases among people with HIV in developing countries is not known. Further research is needed of the effectiveness of interventions especially necrotizing disease in developing countries. The quality of research of these diseases would be enhanced by standardized approaches. A list of relevant variables might prevent their omission from studies.
Telomeres, Telomerase, and Telomerase Inhibition: Clinical Implications for Cancer
Authors: Ahmed Ali , Tollefsbol Trygve
Published: March 2003

Telomeres are located at the ends of eukaryotic chromosomes. The enzyme telomerase synthesized them, and they are responsible for maintaining the lengths of chromosomes. Absence of telomerase is associated with telomere shortening and aging of somatic cells, but high telomerase activity is observed in over 90% of human cancer cells. Although the disappearance of telomerase with aging is considered a natural defense against development of cancer, it is not known what triggers the reappearance of telomerase in cancer cells. Telomerase activity is directly correlated with the expression of its active catalytic component, the human telomerase reverse transcriptase (hTERT), which is controlled primarily at the level of transcription.

An earlier paper discussed the relationship of telomerase with aging. In this article, the contemporary literature is reviewed to explore the associations between telomerase, telomerase inhibition, and cancer. Because most cancers occur in old age, with the aging of the population, the number of people suffering from cancer is expected to increase in the coming decades. It is not known what roles telomerase and hTERT play in the complex relationship between aging and cancer. Data from experimental studies suggest that telomerase assay could potentially play a role in the diagnosis and prognosis of cancers. There is also evidence that telomerase inhibitors might be used as anticancer agents. As the knowledge of the relationships between telomerase and cancer and between telomerase and aging advances, it is hoped that more about the interacting relationships between telomerase, aging, and cancer will be learned.
Thermodynamic characterization of yeast triosephosphate isomerase refolding: insights into the interplay between function and stability as reasons for the oligomeric nature of the enzyme
Authors: NÁJERA Hugo , COSTAS Miguel , FERNÁNDEZ-VELASCO D. Alejandro
Published: March 2003

The reasons underlying the oligomeric nature of some proteins such as triosephosphate isomerase (TIM) are unclear. It has been proposed that this enzyme is an oligomer, mainly because of its stability rather than for functional reasons. To address this issue, the reversible denaturation and renaturation of the homodimeric TIM from baker's yeast (Saccharomyces cerevisiae) induced by guanidinium chloride and urea have been characterized by spectroscopic, functional and hydrodynamic techniques. The unfolding and refolding of this enzyme are not coincident after ‘conventional’ equilibrium times. Unfolding experiments did not reach equilibrium, owing to a very slow dissociation and/or unfolding process. By contrast, equilibrium was reached in the refolding direction. The simplest equilibrium pathway compatible with the obtained data was found to be a three-state process involving an inactive and expanded monomer. The Gibbs energy changes for monomer folding (ΔGfold0 = −16.6±0.7kJ·mol-1) and monomer association (ΔGassoc0 = −70.3±1.1kJ·mol-1) were calculated from data obtained in the two denaturants. From an analysis of the present data and data from the literature on the stability of TIM from different species and for other β/α barrels, and model simulations on the effect of stability in the catalytic activity of the enzyme, it is concluded that the low stability of the monomers is neither the only, nor the main, cause for the dimeric nature of TIM. There is interplay between function and stability.
beta-Glucosidase in cellulosome of the anaerobic fungus Piromyces sp. strain E2 is a family 3 glycoside hydrolase
Authors: STEENBAKKERS Peter J.M. , HARHANGI Harry R. , BOSSCHER Mirjam W. , HOOFT Marlous M.C. van der , KELTJENS Jan T. , DRIFT Chris van der , VOGELS Godfried D. , CAMP Huub J.M. OP DEN
Published: March 2003

The cellulosomes of anaerobic fungi convert crystalline cellulose solely into glucose, in contrast with bacterial cellulosomes which produce cellobiose. Previously, a β-glucosidase was identified in the cellulosome of Piromyces sp. strain E2 by zymogram analysis, which represented approx. 25% of the extracellular β-glucosidase activity. To identify the component in the fungal cellulosome responsible for the β-glucosidase activity, immunoscreening with anti-cellulosome antibodies was used to isolate the corresponding gene. A 2737bp immunoclone was isolated from a cDNA library. The clone encoded an extracellular protein containing a eukaryotic family 3 glycoside hydrolase domain homologue and was therefore named cel3A. The C-terminal end of the encoded Cel3A protein consisted of an auxiliary domain and three fungal dockerins, typical for cellulosome components. The Cel3A catalytic domain was expressed in Escherichia coli BL21 and purified. Biochemical analyses of the recombinant protein showed that the Cel3A catalytic domain was specific for β-glucosidic bonds and functioned as an exoglucohydrolase on soluble substrates as well as cellulose. Comparison of the apparent Km and Ki values of heterologous Cel3A and the fungal cellulosome for p-nitrophenyl-β-d-glucopyranoside and d-glucono-1,5-Δ-lactone respectively indicated that cel3A encodes the β-glucosidase activity of the Piromyces sp. strain E2 cellulosome.
Low levels of glutathione peroxidase 1 activity in selenium-deficient mouse liver affect c-Jun N-terminal kinase activation and p53 phosphorylation on Ser-15 in pro-oxidant-induced aponecrosis
Authors: CHENG Wen-Hsing , ZHENG Xinmin , QUIMBY Fred R. , RONEKER Carol A. , LEI Xin Gen
Published: March 2003

Low levels of hepatic selenium (Se)-dependent glutathione peroxidase 1 (GPX1) activity have been shown to protect against oxidative liver injury in Se-deficient mice. The objective of the present study was to determine if the GPX1 protection was associated with phosphorylations of c-Jun N-terminal kinase (JNK) and p53 on Ser-15, two key signalling events in oxidative-stress-mediated cell death. Both Se-deficient GPX1 knockout (GPX1-/-) and wild-type (WT) mice (n = 64) were pretreated with an intraperitoneal injection of Se (as sodium selenite, 50μg/kg body weight) 6h before an intraperitoneal injection of paraquat (12.5mg/kg). Liver aponecrosis, a mixed form of cell death sharing apoptosis and necrosis, was induced by paraquat in both groups of mice. However, its appearance was remarkably delayed and the severity was decreased by the repletion of hepatic GPX1 activity to <4% of the normal level by the Se injection in the WT mice, compared with that in the GPX1-/- mice. Consistently, the WT mice had lower levels of hepatic phospho-JNK, p53 and phospho-p53 (Ser-15) when compared with the GPX1-/- mice at 1—10h after paraquat injection. Incubating liver homogenates with antibodies raised against JNK or phospho-JNK resulted in co-immunoprecipitation of phospho-p53 (Ser-15), and the amounts of the precipitated phospho-p53 were greater in the GPX1-/- mice when compared with that in the WT mice. The co-precipitated complex by the anti-phospho-JNK antibody was capable of phosphorylating intrinsic or extrinsic p53 on Ser-15. In conclusion, phospho-JNK may catalyse phosphorylation of p53 on Ser-15 in Se-deficient mouse liver under moderate oxidative stress, and attenuation of that cascade by low levels of GPX1 activity is associated with its protection against the pro-oxidant-induced liver aponecrosis.
Effects of Early Undernutrition on the Brain Insulin‐Like Growth Factor‐I System
Authors: Chowen J. A. , Goya L. , Ramos S. , Busiguina S. , García‐Segura L. M. , Argente J. , Pascual‐Leone A. M.
Published: March 2003

Undernutrition reduces circulating concentrations of insulin‐like growth factor (IGF)‐I, but how it affects the brain IGF system, especially during development, is largely unknown. We have studied IGF‐I, IGF‐II, IGF receptor and IGF binding protein (BP)‐2 mRNA expression in the hypothalamus, cerebellum and cerebral cortex of neonatal rats that were food restricted beginning on gestational day 16. One group was refed starting on postnatal day 14. Rats were killed on postnatal day 8 or 22. Undernutrition did not produce an overall reduction in brain weight at either age but, at 22 days, both the cerebellum and hypothalamus weighed significantly less. At 8 days, no change was detected in the central IGF axis in response to undernutrition. However, in 22‐day‐old undernourished rats, IGF‐I and IGF receptor mRNA expression were increased in both the hypothalamus and cerebellum, while IGFBP‐2 was decreased, but only in the hypothalamus. Refeeding had no effect on any of these parameters. These results suggest that the hypothalamus and cerebellum respond to malnutrition and the decrease in circulating IGF‐I, a peptide fundamental for growth and development, by increasing the local production of both the growth factor and its receptor in attempt to maintain normal development.
The role of epidermal turgor in stomatal interactions following a local perturbation in humidity
Authors: Mott K. A. , Franks P. J.
Published: March 2003

Humidity in a small area of a Vicia faba L. leaf was perturbed with a flow of dry air from an 80 µm (inside diameter) needle, while the remainder of the leaf was maintained at high and constant humidity. The influence of the needle flow on the humidity at the leaf surface was quantified by using a spatially explicit dewpoint hygrometer to observe condensation patterns. When the dry air from a needle was applied to the leaf, stomata within the influence of the needle opened within the first few minutes of the perturbation, and local epidermal turgor pressure declined within the same time frame. When the needle flow was removed from the leaf, these responses were reversed, but with more variable kinetics. Stomata and epidermal cells outside the influence of the needle flow, which were exposed to a constant and high humidity, showed similar, but smaller, responses when the needle flow was applied to the leaf. Since the opening of these stomata should have had only a small effect on transpiration (because of the high humidity), it is likely that the reduction in epidermal turgor was the cause (rather than the result) of the stomatal opening. The magnitude of the turgor response was only loosely related to the distance from the needle flow up to distances of almost 400 µm. The data support the idea that neighbouring stomata can interact through the influence of transpiration on epidermal turgor.
A quantitative study of day–night changes in the spatial distribution of insects in a stony stream
Authors: Elliott J. M.
Published: March 2003

As many invertebrates are nocturnal, their spatial distribution may change from day to night. This behavioural aspect of their population dynamics has been ignored, but is now examined for the first time by testing the hypotheses: (i) a power function was a suitable model for the spatial distribution of common species of Ephemeroptera, Plecoptera and Trichoptera in a stony stream; (ii) the spatial distribution varied between species but was similar within species for larvae greater and smaller than half‐size; (iii) diurnal and nocturnal spatial distributions were significantly different for each species. To ensure that the conclusions were consistent, large samples (n = 30) were taken near midday and midnight in April, June and November over 4 years.

Twenty–one species were taken in sufficient numbers for the analyses; seven species were too sparse to be included. The first hypothesis was supported. A power function, relating spatial variance (s2) to mean (m), was an excellent fit in all the analyses (P < 0·001, r2 > 0·95), i.e. the spatial variance was density–dependent. The power b, often used as an ‘index of aggregation’, varied in the range 0·88–2·50.

Most analyses supported the second hypothesis. For four species, the difference between the two size groups was just significant (P < 0·05), but was due to inadequate data for three species. Large larvae of the fourth species, the caddis Odontocerum albicorne, were less aggregated than small larvae at night, and were the only group with a b‐value less than one.

The third hypothesis was partially supported. The distribution did not change significantly (P > 0·05) for nine species; five burrowers in gravel, moss or mud, two highly mobile predators, one sedentary, case–building, Trichoptera species, and one net–spinning Trichoptera species. Aggregation was reduced significantly (P < 0·001) at night for four species, all case–building Trichoptera larvae. Aggregation increased significantly (P < 0·001) at night, except at low densities, for the remaining eight species, one being a nocturnal predator and the others being herbivorous species; all occurred frequently in night samples of invertebrate drift. Day–night changes in spatial distribution were therefore an essential part of the behavioural dynamics of 12 of the 21 species, and should be investigated in other species, including terrestrial species.
The distribution of the anti‐HIV drug, 2′3′‐dideoxycytidine (ddC), across the blood–brain and blood–cerebrospinal fluid barriers and the influence of organic anion transport inhibitors
Authors: Gibbs J. E. , Thomas S. A.
Published: March 2003

The brain and CSF distribution of the HIV reverse transcriptase inhibitor, 2′3′‐dideoxycytidine (ddC), was investigated by the in situ brain perfusion and isolated incubated choroid plexus methods in the guinea pig. Multiple‐time brain perfusions indicated that the distribution of [3H]ddC to the brain and CSF was low and the unidirectional rate constant (Kin) for the brain uptake of this nucleoside analogue (0.52 ± 0.10 µL/min/g) was not significantly different to that for the vascular marker, [14C]mannitol (0.44 ± 0.09 µL/min/g). The influence of unlabelled ddC, six organic anion transport inhibitors and 3′‐azido 3′‐deoxythymidine (AZT) on the CNS uptake of [3H]ddC was examined in situ and in vitro. ddC, probenecid and 2,4‐dichlorophenoxyacetic acid altered the distribution of [3H]ddC into the brain and choroid plexuses, indicating that the limited distribution of [3H]ddC was a result of an organic anion efflux transporter, in addition to the low lipophilicity of this drug (octanol‐saline partition coefficient, 0.047 ± 0.001). The CNS distribution was also sensitive to p‐aminohippurate and deltorphin II, but not digoxin, suggesting the involvement of organic anion transporters (OAT1/OAT3‐like) and organic anion transporting polypeptides (OATP1/OATPA‐like). AZT did not effect the accumulation of [3H]ddC, indicating that when these nucleoside analogues are used in anti‐HIV combination therapy, the CNS distribution of ddC is unchanged.
Mitochondria regulate Ca2+ wave initiation and inositol trisphosphate signal transduction in oligodendrocyte progenitors
Authors: Haak Laurel L. , Grimaldi Maurizio , Smaili Soraya S. , Russell James T.
Published: March 2003

Mitochondria in oligodendrocyte progenitor cells (OPs) take up and release cytosolic Ca2+ during agonist‐evoked Ca2+ waves, but it is not clear whether or how they regulate Ca2+ signaling in OPs. We asked whether mitochondria play an active role during agonist‐evoked Ca2+ release from intracellular stores. Ca2+ puffs, wave initiation, and wave propagation were measured in fluo‐4 loaded OP processes using linescan confocal microscopy. Mitochondrial depolarization, measured by tetramethyl rhodamine ethyl ester (TMRE) fluorescence, accompanied Ca2+ puffs and waves. In addition, waves initiated only where mitochondria were localized. To determine whether energized mitochondria were necessary for wave generation, we blocked mitochondrial function with the electron transport chain inhibitor antimycin A (AA) in combination with oligomycin. AA decreased wave speed and puff probability. These effects were not due to global changes in ATP. We found that AA increased cytosolic Ca2+, markedly reduced agonist‐evoked inositol trisphosphate (IP3) production, and also enhanced phosphatidylinositol 4,5‐bisphosphate (PIP2) binding to the Ca2+ dependent protein gelsolin. Thus, the reduction in puff probability and wave speed after AA treatment may be explained by competition for PIP2 between phospholipase C and gelsolin. Energized mitochondria and low cytosolic Ca2+ concentration may be required to maintain PIP2, a substrate for IP3 signal transduction.
Mitochondrial DNA and respiratory chain function in spinal cords of ALS patients
Authors: Wiedemann Falk R. , Manfredi Giovanni , Mawrin Christian , Beal M. Flint , Schon Eric A.
Published: March 2003

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterized by selective motor neuron death. In order to address the question of a putative role of mitochondrial dysfunction in the pathogenesis of ALS, we studied the mitochondrial DNA (mtDNA) and mitochondrial respiratory chain enzyme activities in spinal cords of ALS patients and in control subjects without neuropathologic abnormalities. Using a ‘double PCR and digestion’ technique to estimate the levels of randomly distributed point mutations in two small regions of the mtDNA, we found significantly higher levels of mutant mtDNA in the spinal cord of ALS patients compared to controls. No large‐scale rearrangements were found, but the amount of mtDNA, measured by Southern blot, was significantly lower in the ALS samples. This reduction correlated well with a decrease of citrate synthase (CS) activity, a mitochondrial marker, as were the activities of respiratory chain complexes I + III, II + III, and IV, suggesting a loss of mitochondria in ALS spinal cords.
Effect of prenatal and postnatal ethanol exposure on the developmental profile of mRNAs encoding NMDA receptor subunits in rat hippocampus
Authors: Naassila Mickaël , Daoust Martine
Published: March 2003

It has been proposed that assembly of the final NMDA receptor complex may be modified by prenatal ethanol exposure, resulting in long‐term alterations of NMDA receptor pharmacology. We investigated the effect of prenatal and postnatal ethanol exposure on the developmental profile of mRNAs encoding NMDA receptor subunits in rat hippocampus. Female Sprague–Dawley rats were chronically intoxicated for 4 weeks with a 10% (v/v) ethanol solution administered throughout pregnancy and lactation. Hippocampus and cerebellum were isolated from pups (postnatal days 1–28) of the ethanol‐exposed and ad libitum groups. Our results, using a semiquantitative RT‐PCR technique, showed a selective effect of ethanol exposure on the various NMDA receptor subunits. Ethanol exposure significantly increased the levels of NR11XX, NR1X11 and NR2D mRNAs on postnatal days 7 and 14 and decreased the level of NR2C on postnatal day 1. Immunoblot analyses demonstrated that NR2D protein levels were increased on postnatal day 7 after ethanol exposure. However, the developmental profile of mRNAs encoding for NR2A–B, NR3L/S, GBP and Gly/TCP‐BP subunits were not affected. Moreover, no significant effects of ethanol exposure were observed on the developmental transition from expression of NR10XX to NR1XX splice variants occurring in the cerebellum on postnatal day 19. Unexpectedly, [3H]MK‐801 binding experiments showed that ethanol exposure increased the Bmax values of high‐affinity sites on postnatal days 14 and 28, with no change of Kd values. These findings indicate that prenatal and/or postnatal ethanol exposure alters the hippocampal levels of mRNAs encoding for certain subunits and the density of high‐affinity [3H]MK‐801 binding sites. As these subunits have been shown to modulate the functional properties of NMDA receptors, these results suggest that this altered expression could be involved in the neurodevelopmental disorders associated with fetal ethanol exposure.
Effect of precipitated morphine withdrawal on post‐translational processing of prothyrotropin releasing hormone (proTRH) in the ventrolateral column of the midbrain periaqueductal gray
Authors: Nillni Eduardo A. , Lee Alison , Legradi Gabor , Lechan Ronald M.
Published: March 2003

We have demonstrated that during opiate withdrawal, preprothyrotropin releasing hormone (preproTRH) mRNA is increased in neurons of the midbrain periaqueductal gray matter (PAG) while the concentration of TRH remained unaltered, suggesting that the processing of proTRH may be different in this region of the brain. The aim of the present study was to determine which of the proTRH‐derived peptides are affected by opiate withdrawal in the PAG. These changes were compared to other TRH‐containing areas such as the hypothalamic paraventricular nucleus (PVN), median eminence (ME) and the lateral hypothalamus (LH). Control and morphine‐treated rats 24 h following naltrexone‐precipitated withdrawal were decapitated and the brain microdissected. Pooled samples from each animal group were acid extracted, and peptides were electrophoretically separated then analyzed by specific radioimmunoassay. Opiate withdrawal caused a significant change in the level of some post‐translational processing products derived from the TRH precursor. In the PAG, opiate withdrawal resulted in an accumulation of the intervening preproTRH83−106 peptide from the N‐terminal side of the prohormone, while the levels of the C‐terminal preproTRH208‐‐285 peptide were reduced, with no change in preproTRH25−50 or TRH, itself, as compared to control animals. Immunohistochemical analysis also showed significant increases in cellular preproTRH83−106 peptide immunolabeling in the PAG. Opiate withdrawal in the lateral hypothalamus, unlike from the PAG, was accompanied by an increase in the concentration of TRH. In addition, western blot analysis showed that during opiate withdrawal, the mature form of the prohormone convertase 2 (PC2) increased only in PAG as compared with their respective controls. Thus, these results demonstrate a region‐specific regulation of TRH prohormone processing in the brain, which may engage PC2, further suggesting a role for specific proTRH‐derived peptides in the manifestations of opiate withdrawal.
An evaluation of noninvasive methods to estimate foliar chlorophyll content
Authors: Richardson Andrew D. , Duigan Shane P. , Berlyn Graeme P.
Published: March 2003

Over the last decade, technological developments have made it possible to quickly and nondestructively assess, in situ, the chlorophyll (Chl) status of plants. We evaluated the performance of these optical methods, which are based on the absorbance or reflectance of certain wavelengths of light by intact leaves.

 As our benchmark, we used standard extraction techniques to measure Chla, Chlb, and total Chl content of paper birch (Betula papyrifera) leaves. These values were compared with the nominal Chl index values obtained with two hand‐held Chl absorbance meters and several reflectance indices correlated with foliar Chl.

 The noninvasive optical methods all provided reliable estimates of relative leaf Chl. However, across the range of Chl contents studied (0.0004–0.0455 mg cm−2), some reflectance indices consistently out‐performed the hand‐held meters. Most importantly, the reflectance indices that performed best   were not those most commonly used in the literature.

 We report equations to convert from index values to actual Chl content, but caution that differences in leaf structure may necessitate species‐specific calibration equations.
Short‐term waterlogging has long‐term effects on the growth and physiology of wheat
Authors: Malik Al Imran , Colmer Timothy D. , Lambers Hans , Setter Timothy L. , Schortemeyer Marcus
Published: March 2003

The effect of different durations of waterlogging and subsequent drainage is described for 3‐wk‐old wheat (Triticum aestivum) plants.

 In a pot experiment, plants were subjected to waterlogging to the soil surface for 0, 3, 7, 14, 21 or 28 d, and then drained to allow recovery for up to 25 d.

 During waterlogging, the seminal root system stopped growing. Adventitious roots grew to a maximum length of c. 150 mm. Leaf nitrogen concentration was severely decreased by waterlogging. When waterlogged pots were drained, seminal root mass did not recover to control values, even when waterlogging lasted only 3 or 7 d, due to death of existing apices and no initiation of new lateral roots. By contrast, adventitious roots resumed elongation after drainage. By the end of the experiment, shoot mass remained two‐ to threefold lower in plants from all waterlogged treatments compared with continuously drained controls, due to lower tiller numbers and shorter final leaf lengths in previously waterlogged plants.

 The results demonstrate that even short periods (as little as 3 d) of waterlogging have considerable long‐term effects on the growth of young wheat plants.