bluuebunny/crossref_metadata_2025 huggingface dataset:
The importance of experimental design in detecting the effects of protection measures on fish in Mediterranean MPAs
Authors: Guidetti P.
Published: November 2002

Marine Protected Areas (MPAs) are currently proliferating in the Mediterranean Sea. The assessment of their role in the protection and recovery of overexploited fish populations, however, is not yet completely supported by an adequate body of scientific evidence. This is in part because the number of studies that unambiguously assess changes induced by protection is limited.

Sampling to detect and measure the expected effects of protection on commercial fish (e.g. increase in mean abundance and size) is made difficult by intrinsic natural spatial and temporal variability. Ideally, temporal replication before and after the establishment of MPAs is necessary for estimating the average conditions in time. Spatial replication of control locations, on the other hand, is essential to prevent confusion in interpreting a difference between protected and unprotected locations. Until now, the basic requirements for appropriate experimental designs in MPAs were seldom satisfied, especially in the Mediterranean region.

In the present paper, an ideal experimental design aimed at overcoming many of the confounding influences that could result in misinterpretations of the results is considered, with a discussion of implications of applying less and less appropriate designs because of pragmatic constraints. Experimental design should thus be adapted to each individual MPA under study on the basis of the specific constraints that researchers face (e.g. ‘before’ (i.e. pre‐designation) data are lacking; there is a single or more than one protected locations).

The issues related to MPAs, chiefly in the Mediterranean region, need to be considered to enable the identification of unambiguous hypotheses prior to sampling, based on clear logical structures. The importance of appropriate sampling and the subsequent interpretation of data would progressively reduce the degree of uncertainty of environmental analyses about the effects of MPAs on fish, with important implications for their management and further proliferation.

Copyright © 2002 John Wiley & Sons, Ltd.
Floodplains of a regulated southern alpine river (Brenno, Switzerland): ecological assessment and conservation options
Authors: Brunke M.
Published: November 2002

The fifth‐order southern alpine Brenno River and its floodplains are severely impaired by embankments, water abstractions and the construction of dams for hydropower generation. The river's annual mean discharge is reduced to 27% of the natural flow and the number of small (50–100 m3 s−1) and medium‐sized (101–150 m3 s−1) floods is reduced significantly.

Lateral hydrological connectivity has decreased strongly as a result of the flow regulation, whereas the significance of vertical connectivity has increased. The remnants of the middle and lower floodplains still contain springbrooks, ponds, and intermittently connected channels, which are all sustained by emerging groundwater.

Aquatic floodplain habitats can be classified partially by faunal composition. The lotic/lentic gradient appears to be a dominant compound factor structuring invertebrate assemblages when considering all aquatic habitats. The exfiltration of groundwater in conjunction with a reduced lateral connectivity enables the occurrence of many stenotopic species.

A comparison of present floodplains with those shown on historical maps shows that the fluvial landscape has changed markedly. The proportions of functional floodplain units characterized by autogenic succession and trends to late successional stages (i.e. senescence) have increased.

Floodplains of the Brenno river are still considered to represent important ecological areas and they are protected by law. Whilst the legislative protection of floodplains is the basis for conservation, this does not include the restoration of driving hydrological processes. An annual release of small‐ and medium‐sized floods could generate a diversity of disturbances, thereby promoting rejuvenation and counteracting senescence.

Alternative conservation options that circumvent ongoing contracts of water use, though generally promising, are limited because of the operation of hydropower schemes. At present the exfiltrations of groundwater mitigate the impacts of flow regulation on the ecological integrity of the floodplains.

Copyright © 2002 John Wiley & Sons, Ltd.
Variation in Langerhans cell number and morphology between the upper and lower regions of the human esophageal epithelium
Authors: Zavala Walther D. , De Simone Dino Sanchez , Sacerdote Fabio L. , Cavicchia Juan C.
Published: November 2002

Langerhans cells (LCs) are dendritic components of stratified epithelia, presenting antigens to other cells of the immune system that play a crucial role in local defense. The paucity of information about their significance in the esophageal mucosa was addressed by studying their distribution and morphology in this particular location. LCs were identified by immunohistochemical detection of CD1a, a cell‐specific marker, using a monoclonal antibody, as well as by electron microscopic identification of characteristic Birbeck granules, among other typical morphological features. Cell counts carried out at 25 and 35 cm distal to the dental arch demonstrated significant differences in number and size between the two locations. The upper region contained 10.4 ± 0.8 cells (mean ± SEM) vs. 18.4 ± 1.4 cells in the lower region. Also, cells in the lower region were larger and appeared to have longer dendritic processes. To our knowledge this is the first report of regional differences in number and morphology of LCs in human esophageal mucosa. Anat Rec 268:360–364, 2002. © 2002 Wiley‐Liss, Inc.
The structure of the conus arteriosus of the sturgeon (Acipenser naccarii) heart: II. The myocardium, the subepicardium, and the conus‐aorta transition
Authors: Icardo José M. , Colvee Elvira , Cerra Maria C. , Tota Bruno
Published: November 2002

Sturgeons constitute a family of living “fossil” fish whose heart is related to that of other ancient fish and the elasmobranches. We have undertaken a systematic study of the structure of the sturgeon heart aimed at unraveling the relationship between the heart structure and the adaptive evolutionary changes. In a related paper, data were presented on the conus valves and the subendocardium. Here, the structure of the conus myocardium, the subepicardial tissue, and the conus‐aorta transition were studied by conventional light, transmission, and scanning electron microscopy. In addition, actin localization by fluorescent phalloidin was used. The conus myocardium is organized into bundles whose spatial organization changes along the conus length. The variable orientation of the myocardial cell bundles may be effective in emptying the conus lumen during contraction and in preventing reflux of blood. Myocardial cell bundles are separated by loose connective tissue that contains collagen and elastin fibers, vessels, and extremely flat cells separating the cell bundles and enclosing blood vessels and collagen fibers. The ultrastructure of the myocardial cells was found to be very similar to that of other fish groups, suggesting that it is largely conservative. The subepicardium is characterized by the presence of nodular structures that contain lympho‐hemopoietic (thymus‐like) tissue in the young sturgeons and a large number of lymphocytes after the sturgeons reach sexual maturity. This tissue is likely implicated in the establishment and maintenance of the immune responses. The intrapericardial ventral aorta shows a middle layer of circumferentially oriented cells and internal and external layers with cells oriented longitudinally. Elastin fibers completely surround each smooth muscle cell, and the spaces between the different layers are occupied by randomly arranged collagen bundles. The intrapericardial segment of the ventral aorta is a true transitional segment whose structural characteristics are different from those of both the conus subendocardium and the rest of the ventral aorta. Anat Rec 268:388–398, 2002. © 2002 Wiley‐Liss, Inc.
Enhanced immunocytochemical expression of antioxidant enzymes in rat submandibular gland after normobaric oxygenation
Authors: Morita Miyako , Kudo Hideaki , Doi Yoshiaki , Hirano Takeshi , Ikemura Kunio , Fujimoto Sunao
Published: November 2002

In order to clarify the role of antioxidant enzymes in the male rat submandibular gland against short‐term normobaric oxygenation, we performed immunocytochemical staining of manganese‐containing superoxide dismutase (Mn‐SOD), copper‐ and zinc‐containing SOD (Cu/Zn‐SOD), catalase (CAT), glutathione peroxidase, and glutathione S‐transferases (GST alpha, GST mu, and GST pi) between days 1 and 7 after normobaric oxygenation. Ultrastructural alterations and immunoreactivities for malondialdehyde (MDA), a lipid peroxidation‐related molecule, of the acinar and ductal cells after the oxygenation were also investigated. Immunoreactivity for MDA was exhibited in the acinar cells throughout the experiment. On the other hand, immunoreactivity for the SODs, CAT, and GSTs was not altered, when compared to that of controls, but was significantly elevated in the granular, striated, and excretory ductal cells. Since an increase of lipid peroxidation as indicated by enhanced immunoreactivity for MDA was detected in the acinar and intercalated ductal cells, the results indicate that the enhanced antioxidant enzymes in the granular, striated, and excretory ductal cells play a crucial role in the self‐defense system of the male rat submandibular gland against normobaric oxygenation. Anat Rec 268:371–380, 2002. © 2002 Wiley‐Liss, Inc.
Microvascularization of the hypermineralized calcified fibrocartilage and cortical bone in the sheep proximal femur
Authors: Shea Jill E. , Hallows Rhett K. , Ricks Shannon , Bloebaum Roy D.
Published: November 2002

It is well known that the incidence of hip fractures is increasing as the population ages, and that vascularity is one of the most important characteristics for any tissue (the proximal femur being no exception). Additionally, calcified fibrocartilage from tendon and ligament insertions comprises a significant portion of the fractional area of the proximal femur's cortical shell. The goal of the present investigation was to quantify and compare the microvascularity of the cortical bone and calcified fibrocartilage of the proximal femur in a sheep model. There were no regional differences in the vascular density of the cortical bone. However, the calcified fibrocartilage from tendon and capsular insertions were determined to be avascular, and regions of the proximal femur with insertions lacked a vascularized periosteum. If a vessel was present in the calcified fibrocartilage, it was located within an isolated region of bone tissue or osteoid. Since blood vessels appear to be a significant contributor to the health and remodeling of mineralized tissue, it is hypothesized that the large areas of avascular calcified fibrocartilage present on the elderly femoral neck may predispose these regions to damage accumulation. Therefore future research should examine the role of the vascularity to the proximal femur in the mechanisms of numerous pathological conditions, such as avascular necrosis, osteopenia, and hip fractures. Anat Rec 268:365–370, 2002. Published 2002 Wiley‐Liss, Inc.
Qualitative and quantitative morphology of renal nerves in C57BL/6J mice
Authors: Fazan Valéria Paula Sassoli , Ma Xiuying , Chapleau Mark W. , Barreira Amilton Antunes
Published: November 2002

The detailed morphology of the renal nerves in mice has not been reported previously. The aims of this study were to describe the general morphology of the extrinsic renal nerve in C57BL/6 mice, and determine its morphometric parameters. The major renal nerve innervating the left kidney was isolated in five mice. Thin sections of the nerve segments were then examined by transmission electron microscopy. The renal nerve averaged 35.4 ± 3.6 (S.E.M.) μm in diameter and 741 ± 104 μm in area. The renal nerve contained an average of 830 ± 169 unmyelinated fibers and only 4.6 ± 1.7 myelinated fibers. The axon diameter of myelinated and unmyelinated fibers averaged 2.2 ± 0.3 μm and 0.76 ± 0.02 μm, respectively. The diameter of the unmyelinated fibers ranged from 0.3 to 2.0 μm, and the distribution histogram was unimodal. The majority of fibers (85%) had diameters of 0.6–1.0 μm. These results are similar to those obtained for renal nerves of rats with respect to the predominance of unmyelinated fibers. However, the diameter of unmyelinated fibers is larger in rats and the distribution histogram of rat unmyelinated fibers is bimodal, in contrast to the unimodal distribution in mice. The morphological description of the renal nerves in mice provides baseline data for further investigations of the structural basis of altered autonomic reflexes. The results will be useful in analyses of genes that influence the development and structure of sympathetic and sensory innervation of the kidney in genetically manipulated mice. Anat Rec 268:399–404, 2002. © 2002 Wiley‐Liss, Inc.
Distribution of the elastic fiber and associated proteins in flexor tendon reflects function
Authors: Ritty Timothy M. , Ditsios Konstantinos , Starcher Barry C.
Published: November 2002

The elastic fiber is known to be an important component of skin, lung, and vasculature. Much less is known about the distribution of elastin and elastic fiber‐related proteins in connective tissues, yet genetic defects of elastic fiber constituents can lead to deficiencies in these tissues. For the first time, we determine the distribution of elastin, fibrillins 1 and 2, and microfibril‐associated glycoproteins (MAGPs) 1 and 2 in the flexor digitorum profundus (FDP) tendon. Three functionally distinct regions of the FDP tendon, the fibrocartilagenous (FC) region, avascular/tensional (AV/T) region, and insertion region, were evaluated by immunohistochemical methods for these five proteins. Biochemical analysis of desmosine content, an elastin‐specific cross‐link, demonstrated the presence of elastin in each region, and this was verified histochemically. The fibrillins were found with elastin and also pericellularly with internal fibroblasts where elastin was not detected. Although there was overlapping distribution, fibrillin 2 was more prominent in the interior of the tendon while fibrillin 1 was prominent in outer cell layers that contained elastic fibers. Both MAGP‐1 and ‐2 were found throughout the tendon, although the greatest abundance was near the tendon insertion to bone. Surprisingly, MAGP‐1 demonstrated a filamentous appearance within the fibrocartilage that did not correspond to the fibrillin 1 or 2 or MAGP‐2 staining pattern. Lastly, we have shown that a vincular membrane located along the dorsal surface of the tendon near the insertion has a very high elastin content and a unique interface with the tendon that consists of an elastic anchor within the tendon body. Anat Rec 268:430–440, 2002. © 2002 Wiley‐Liss, Inc.
Polarized light microscopic analyses of collagen fibers in the rat incisor periodontal ligament in relation to areas, regions, and ages
Authors: Komatsu Koichiro , Mosekilde Lis , Viidik Andrus , Chiba Mototsugu
Published: November 2002

We prepared decalcified sagittal sections (20 μm thick) from the incisal, middle, and basal regions of the mandibular incisor of male Wistar rats aged 2, 6, 12, and 24 months, and examined the sections using polarized light microscopy. Most of the birefringent fibers appeared to run obliquely across the periodontal ligament. Birefringent fibers running parallel to the long axis of the incisor were also found in the intermediate area of the ligament. Similar fiber architecture was observed in all four age groups. Quantitative analysis showed that the retardation values of collagen were higher in the bone‐ and tooth‐related areas and lower in the intermediate area of the ligament. The values for the bone‐ and tooth‐related areas increased from the basal toward the incisal regions in all four age groups. Age‐related changes in the retardation values were found only in the incisal region of the incisor. In the incisal region, the values for the bone‐ and tooth‐related areas increased markedly from 2–24 months of age, whereas those for the intermediate area increased slightly but significantly with age. Our findings indicate that the degrees of molecular organization and alignment of collagen fibers in the bone‐ and tooth‐related areas of the ligament are higher than those in the intermediate area and increase near the incisal region and with age. It is also suggested that the collagen fibers in the intermediate area remain immature along the long axis of the incisor throughout the life span of the animal. Anat Rec 268:381–387, 2002. © 2002 Wiley‐Liss, Inc.
Urorectal septum malformation sequence: Insights into pathogenesis
Authors: Jo Mauch Teri , Albertine Kurt H.
Published: November 2002

We characterize the urorectal septum malformation sequence (URSMS) in discordant fetal lambs and relate it to the human syndromes with which URSMS is associated. We found abnormal external genitalia, imperforate anus, and fistulous connections between the rectum, bladder, and vagina. Discordance among the dizygous twins eliminated teratogens as a likely etiologic factor. We summarize the relevant literature and propose a molecular model for the pathogenesis of the URSMS, in which alterations in sonic hedgehog and homeobox genes lead to caudal mesodermal deficiency during blastogenesis. Anat Rec 268:405–410, 2002. © 2002 Wiley‐Liss, Inc.
Neuroanatomy of the common dolphin (Delphinus delphis) as revealed by magnetic resonance imaging (MRI)
Authors: Marino Lori , Sudheimer Keith D. , Pabst D. Ann , Mclellan William A. , Filsoof David , Johnson John I.
Published: November 2002

In this study, magnetic resonance (MR) images of the brain of an adult common dolphin (Delphinus delphis) were acquired in the coronal plane at 66 antero‐posterior levels. From these scans a computer‐generated set of resectioned virtual images in orthogonal planes was constructed using the programs VoxelView and VoxelMath (Vital Images, Inc., Michigan State Univ.). Sections in all three planes reveal major neuroanatomical structures. These structures in the adult common dolphin brain are compared with those from a fetal common dolphin brain from a previously published study as well as with MR images of adult brains of other odontocetes. This study, like previous ones, demonstrates the utility of MR imaging (MRI) for comparative neuroanatomical investigations of dolphin brains. Anat Rec 268:411–429, 2002. © 2002 Wiley‐Liss, Inc.
Description of a poorly differentiated carcinoma within the brainstem of a white whale (Delphinapterus leucas) from magnetic resonance images and histological analysis
Authors: Ridgway S.H. , Marino L. , Lipscomb T.P.
Published: November 2002

In this study we used magnetic resonance imaging (MRI) to investigate neuroanatomical structure in the brain of a white whale (Delphinapterus leucas) that died from a large tumor within the brainstem. This specimen was also compared with a normal white whale brain using MRI. MRI scans of the white whale specimen show how the tumor deformed surrounding brain structure. Histopathological analysis indicated a poorly differentiated carcinoma of uncertain origin. These analyses demonstrate the usefulness of supplementing histological analyses of pathology with studies of gross morphology facilitated by MRI. Anat Rec 268:441–449, 2002. © 2002 Wiley‐Liss, Inc.
Regulation of the kinetics of intracerebral chemokine gene expression in murine Toxoplasma encephalitis: Impact of host genetic factors
Authors: Strack Andreas , Schlüter Dirk , Asensio Valérie C. , Campbell Iain L. , Deckert Martina
Published: November 2002

The expression and kinetics of a panel of chemokines during Toxoplasma encephalitis (TE) were analyzed in a comparative study of genetically resistant BALB/c and susceptible C57BL/6 mice. In parallel with disease activity and the number of postinfection (p.i.) leukocytes, C57BL/6 mice induced CRG‐2/IP‐10, MuMIG, RANTES, MCP‐1, MIP‐1α, and MIP‐1β earlier and reached increased levels, as compared with BALB/c mice. These differences in the kinetics of intracerebral (i.c.) chemokines may serve as a compensatory mechanism to prevent death from necrotizing TE in C57BL/6 mice; in contrast, BALB/c mice downregulated i.c. chemokines with efficient parasite control in the chronic latent phase. Furthermore, this study showed that the pattern of i.c. chemokines and the cellular sources were identical in both strains of mice, with astrocytes and microglia expressing CRG‐2/IP‐10 and MCP‐1 or RANTES and MuMIG, respectively, and leukocytes transcribing CRG‐2/IP‐10, MCP‐1, and RANTES. Thus, the present study demonstrates that host genetic factors exert a strong impact on i.c. chemokines in experimental murine TE. GLIA 40:372–377, 2002. © 2002 Wiley‐Liss, Inc.
Activation of PP2A‐like phosphatase and modulation of tau phosphorylation accompany stress‐induced apoptosis in cultured oligodendrocytes
Authors: Goldbaum Olaf , Richter‐Landsberg Christiane
Published: November 2002

In a number of neurodegenerative diseases, tau‐positive glial cytoplasmic inclusions (GCIs), immunochemically labeled with antibodies to the small heat shock protein (HSP) αB‐crystallin, occur in oligodendrocytes. The microtubule‐associated protein tau is functionally modulated by phosphorylation. We have shown previously that oxidative stress (OS) and heat shock (HS) induce apoptotic cell death in oligodendrocytes. The present study was undertaken to test whether stress responses in oligodendrocytes cause abnormalities in the expression and posttranslational modification of tau proteins, and whether the dynamic phosphorylation and dephosphorylation of tau are involved in the pathogenesis of glial cells. Cultured rat brain oligodendrocytes were subjected to OS, exerted by hydrogen peroxide, or HS (44°C, 30 min). Immunoblot analysis with a panel of phosphorylation‐dependent antibodies shows that OS and HS caused the rapid dephosphorylation of tau proteins at multiple sites, before characteristic features of apoptosis were observed. Concomitantly, ERK1,2 (extracellular signal‐regulated kinase) was activated. Tau phosphorylation and rephosphorylation after stress was mediated by glycogen synthase kinase 3β (GSK‐3β), and not by ERK1,2 and could be suppressed by lithium chloride, a specific inhibitor of GSK‐3β. Stress‐induced dephosphorylation could be mimicked by alkaline phosphatase and suppressed by the protein phosphatase inhibitor okadaic acid (OA), indicating that PP2A in oligodendrocytes is activated by stress. OA at low concentrations could prevent stress‐induced DNA fragmentation, but eventually exerted cytotoxic effects. Hence, stress‐induced activation of PP2A in oligodendrocytes and tau dephosphorylation constitute a major feature of the response to injury in these cells, which eventually undergo apoptotic cell death. GLIA 40:271–282, 2002. © 2002 Wiley‐Liss, Inc.
Trafficking of PLP/DM20 and cAMP signaling in immortalized jimpy oligodendrocytes
Authors: Ghandour M. Said , Feutz Anne‐Catherine , Jalabi Walid , Taleb Omar , Bessert Denise , Cypher Maria , Carlock Leon , Skoff Robert P.
Published: November 2002

The synthesis, transport, and insertion of jimpy proteolipid protein and DM20 were studied in normal (158N) and jimpy (158JP) immortalized oligodendrocyte lines. Four different expression vectors encoding fusion proteins composed of native PLP and DM20 or jimpy PLP or DM20 were linked to enhanced green fluorescent protein (EGFP). All four transfected fusion proteins had similar distributions in the cell bodies and processes of the two cell types. Both normal and jimpy PLP‐EGFP and DM20‐EGFP were detected in both cell lines as far as 200 μm from the cell body, indicating synthesis and transport of mutated PLP and DM20 toward the plasma membrane. Immunocytochemistry of fixed normal and jimpy cells with the O10 antibody, which recognizes a conformationally sensitive PLP/DM20 epitope, confirmed that normal and jimpy PLP and DM20 were transported to the plasma membrane. Live staining of normal and jimpy cells transiently transfected with the native PLP showed positive staining, indicating PLP was correctly inserted into the membrane of both normal and jimpy oligodendrocytes. However, live staining of normal and jimpy cells transiently transfected with jimpy PLP showed no positive staining, indicating the mutated protein is abnormally inserted into the plasma membrane. Electrophysiological recordings of the resting membrane potential measured in the whole cell mode of the patch‐clamp technique showed the absence of a developmentally regulated negative shift in the membrane potential in jimpy cells compared to normal native or immortalized oligodendrocytes. Treatment of 158N cells and native oligodendrocytes with dibutyryl cAMP (dbcAMP) caused morphological and biochemical differentiation, but failed to do so in 158JP cells, suggesting an abnormal signaling pathway in jimpy. The defect in cAMP signaling in jimpy oligodendrocytes was associated with the suppression of increase in mRNA level of the inducible cAMP early repressor (ICER). When the jimpy oligodendrocyte line was transfected with normal PLP or DM20 and exposed to dbcAMP, the cells failed to differentiate. This finding suggests that improper insertion of jimpy protein into the plasma membrane alters the membrane in such a way that certain signaling pathways are permanently altered. The abnormal insertion of jimpy PLP/DM20 into the plasma membrane may be the basis for the lack of cell signaling and abnormal resting potential in jimpy oligodendrocytes. GLIA 40:300–311, 2002. © 2002 Wiley‐Liss, Inc.
Catecholamine‐induced oligodendrocyte cell death in culture is developmentally regulated and involves free radical generation and differential activation of caspase‐3
Authors: Khorchid Amani , Fragoso Gabriela , Shore Gordon , Almazan Guillermina
Published: November 2002

Oligodendrocyte cultures were used to study the toxic effects of catecholamines. Our results showed that catecholamine‐induced toxicity was dependent on the dose of dopamine or norepinephrine used and on the developmental stage of the cultures, with oligodendrocyte progenitors being more vulnerable. A role for oxidative stress and apoptosis on the mechanism of action of catecholamines on oligodendrocyte cell death was next assessed. Catecholamines caused a reduction in intracellular glutathione levels, an accumulation in reactive oxygen species and in heme oxygenase‐1, the 32 kDa stress‐induced protein. All these changes were prevented by N‐acetyl‐L‐cysteine, a thiocompound with antioxidant activity and a precursor of glutathione, and were more pronounced in progenitors than mature cells, which could contribute to their higher susceptibility. Apoptotic cell death, as assessed by activation of caspase‐9 and –3 and cleavage of poly(ADP‐ribose) polymerase (a substrate of caspase‐3), was only observed in oligodendrocyte progenitors. Pretreatment with zVAD, a general caspase inhibitor, prevented activation of caspase‐9 and ‐3, DNA fragmentation, and decreased progenitors cell death. Furthermore, the expression levels of procaspase‐3 and the ratio of the proapoptotic protein bax to antiapoptotic protein bcl‐xl were several folds higher in immature than mature oligodendrocytes. Taken together, these results strongly suggest that the catecholamine‐induced cytotoxicity in oligodendrocytes is developmentally regulated, mediated by oxidative stress, and have characteristics of apoptosis in progenitor cells. GLIA 40:283–299, 2002. © 2002 Wiley‐Liss, Inc.
Nitric oxide induces rapid, calcium‐dependent release of vesicular glutamate and ATP from cultured rat astrocytes
Authors: Bal‐Price Anna , Moneer Zahid , Brown Guy C.
Published: November 2002

Nitric oxide (NO; 1 μM) or an NO donor (500 μM diethylenetriamine‐nitric oxide, DETA‐NONOate) caused rapid glutamate and ATP release from cultured rat cortical astrocytes. NO‐induced glutamate release was prevented by calcium chelators (EGTA or BAPTA‐AM) and an inhibitor of vesicular exocytosis (botulinum neurotoxin C, BoTx‐C), but not by a glutamate transport inhibitor, L‐trans‐pyrrolidine‐2,4‐dicarboxylate (t‐PDC), a cyclooxygenase inhibitor (indomethacin), or an inhibitor of soluble guanylate cyclase 1H‐[1,2,4]oxadiazolo‐[4,3‐a]quinoxalin‐1‐one (ODQ), and was not induced by mitochondrial respiratory inhibitors (myxothiazol or azide). Similarly to glutamate, NO‐induced ATP release was also completely blocked by BAPTA‐AM and BoTx‐C, suggesting again a vesicular, calcium‐dependent mechanism of release. Addition of DETA‐NONOate (500 μM) to fura‐2–loaded astrocytes induced a rapid, transient increase in intracellular calcium levels followed by a lower, sustained level of calcium entry. The latter was blocked by gadolinium (1 μM), an inhibitor of capacitative Ca2+ entry. Thus, NO appears to cause rapid exocytosis of vesicular glutamate and ATP from astrocytes by raising intracellular calcium levels. Astrocytes activated by lipopolysaccharide/endotoxin and interferon‐γ to express inducible NO synthase (iNOS) maintained substantially higher extracellular glutamate levels than nonactivated cells or activated cells treated with an iNOS inhibitor (1400W), but the rate of glutamate uptake by these cells was similar. This suggests that NO from inflammatory‐activated astrocytes causes release of astrocytic glutamate. NO‐induced release of astrocytic glutamate and ATP may be important in physiological or pathological communication between astrocytes and neurons. GLIA 40:312–323, 2002. © 2002 Wiley‐Liss, Inc.
Ammonia‐induced heme oxygenase‐1 expression in cultured rat astrocytes and rat brain in vivo
Authors: Warskulat Ulrich , Görg Boris , Bidmon Hans‐J. , Müller Hans Werner , Schliess Freimut , Häussinger Dieter
Published: November 2002

Ammonia is a key factor in the pathogenesis of hepatic encephalopathy (HE), which is a major complication in acute and chronic liver failure and other hyperammonemic states. The molecular mechanisms underlying ammonia neurotoxicity and the functional consequences of ammonia on gene expression in astrocytes are incompletely understood. Using cDNA array hybridization technique we identified ammonia as a trigger of heme oxygenase‐1 (HO‐1) mRNA levels in cultured rat astrocytes. As shown by Northern and Western blot analysis, HO‐1 mRNA levels were upregulated by ammonia (0.1–5 mmol/L) after 24 h and protein expression after 72 h in astrocytes. These ammonia effects on HO‐1 are probably triggered to a minor extent by ammonia‐induced glutamine synthesis or by astrocyte swelling, because HO‐1 expression was not inhibited by the glutamine synthetase inhibitor methionine sulfoximine (which abrogated ammonia‐induced cell swelling in cultured astrocytes), and ammonia‐induced HO‐1 expression could only partly be mimicked by hypoosmotic astrocyte swelling. Hypoosmotic (205 mOsm/L) exposure of astrocytes led even to a decrease in HO‐1 mRNA levels within 4 h, whereas hyperosmotic (405 mOsm/L) exposure increased HO‐1 mRNA expression. After 24 h, hypoosmolarity slightly raised HO‐1 mRNA expression. Taurine and melatonin diminished ammonia‐induced HO‐1 mRNA or protein expression, whereas other antioxidants (dimethylthiourea, butylated hydroxytoluene, N‐acetylcysteine, and reduced glutathione) increased HO‐1 mRNA levels under ammonia‐free conditions. An in vivo relevance is suggested by the finding that increased HO‐1 expression occurs in the brain cortex from acutely ammonia‐intoxicated rats. It is concluded that ammonia‐induced HO‐1 expression may contribute to cerebral hyperemia in hyperammonic states. GLIA 40:324–336, 2002. © 2002 Wiley‐Liss, Inc.
The tetraspanin protein, CD9, is expressed by progenitor cells committed to oligodendrogenesis and is linked to β1 integrin, CD81, and Tspan‐2
Authors: Terada Nobuo , Baracskay Karen , Kinter Mike , Melrose Shona , Brophy Peter J. , Boucheix Claude , Bjartmar Carl , Kidd Grahame , Trapp Bruce D.
Published: November 2002

Previous studies identified the tetraspanin protein CD9 in myelinating oligodendrocytes. The present report extends these observations by identifying CD9 in a subpopulation of oligodendrocyte progenitor cells (OPCs) and in premyelinating oligodendrocytes in rodents. NG2‐positive cells expressed CD9 in a temporal and spatial pattern during development that was consistent with CD9 expression in OPCs just prior to their differentiation into premyelinating oligodendrocytes. NG2‐positive cells in mature brains were CD9‐negative. CD9 expression during oligodendrocyte development in vitro supported this hypothesis, as all CD9‐positive cells became O4‐positive when switched to oligodendrocyte differentiating media. CD9 immunoreactivity was enriched in myelinating oligodendrocytes and their processes, and the outer aspects of myelin internodes. Immunoprecipitation of CD9 from postnatal rat cerebrum coprecipitated β1 integrin, CD81, and Tspan‐2, another tetraspanin protein recently identified in oligodendrocytes. Following surface biotinylation of oligodendrocytes in vitro, biotinylated β1 integrin was identified in a CD9 immunoprecipitate. These data support a molecular link between surface integrins and a CD9, Tspan‐2 molecular web during the differentiation of oligodendrocytes. Oligodendrocyte production and myelination appears to be normal in CD9‐deficient mice. These data support the hypothesis that CD9 helps form the tetraspanin web beneath the plasma membranes of progenitor cells committed to oligodendrogenesis, but that CD9 is not essential for oligodendrogenesis and myelination. GLIA 40:350–359, 2002. © 2002 Wiley‐Liss, Inc.
Selective inflammatory stimulations enhance release of microglial response factor (MRF)‐1 from cultured microglia
Authors: Tanaka Shuuitsu , Koike Tatsuro
Published: November 2002

The mrf‐1 gene has been isolated from microglia exposed to cultured cerebellar granule neurons undergoing apoptosis. We have shown that mrf‐1 is upregulated in response to neuronal death and degeneration both in vitro and in vivo. However, the exact role of MRF‐1 remains unknown. Here we show that MRF‐1 is released from cultured rat microglia, and its release is greatly enhanced under inflammatory conditions. When microglia were treated with ATP, the amount of MRF‐1 that was released increased 10‐fold compared to the basal level of release. Enhanced MRF‐1 release was induced within 10 min and peaked within 1 h; after ∼ 4 h, the MRF‐1 release had returned to normal. MRF‐1 release was stimulated by 2‐methyl‐thio‐ATP (five‐fold) and a P2X7 selective agonist, 2′‐ and 3′‐O‐(4‐benzoylbenzoyl)‐ATP (ten‐fold). Moreover, the ATP‐stimulated MRF‐1 release was inhibited by a P2X7 selective antagonist, oxidized ATP (oATP), and also under a Ca2+‐free condition. These results indicate that the effects of ATP are dependent on Ca2+ influx through P2X7 receptors. MRF‐1 release was enhanced by Ca2+‐ionophore A23187 (sixfold), thapsigargin (threefold); however, it was not enhanced by glutamate or lipopolysaccharide. Moreover, a platelet‐activating factor enhanced microglial MRF‐1 release in a dose‐dependent manner. We also showed that a conditioned medium from cerebellar granule neurons undergoing apoptosis markedly increased MRF‐1 release from microglia; that effect was significantly inhibited by oATP. These results indicate that selective inflammatory stimulations, including ATP and PAF, enhance MRF‐1 release from microglia through a Ca2+‐dependent mechanism and suggest that MRF‐1 may play a role in cell‐cell interactions under inflammatory conditions. GLIA 40:360–371, 2002. © 2002 Wiley‐Liss, Inc.
cAMP‐dependent reorganization of the Cajal bodies and splicing machinery in cultured Schwann cells
Authors: Fernandez Rosario , Pena Emma , Navascues Joaquin , Casafont Iñigo , Lafarga Miguel , Berciano Maria T.
Published: November 2002

It is well established that forskolin‐induced elevation of cAMP results in activation of DNA synthesis in Schwann cell cultures. This promitotic response is partially mediated by the Cdk2, which is required for the transition from the G1 to the S phase of the cell cycle. In the present study, we analyze the effects of cAMP elevation in cultured Schwann cells on the transcriptional activity and on the organization of two nuclear compartments involved in pre‐mRNA processing: Cajal bodies (CBs) and splicing factor compartments. Our immunofluorescence and quantitative studies show that forskolin treatment induces a 5.6‐fold increase in the proportion of S phase Schwann cells, detected by a short pulse (20 min) of BrdU incorporation. This increase in DNA synthesis correlates with an activation of global transcription, as is indicated by the higher nuclear incorporation of BrU in nascent RNA. Forskolin treatment significantly increases the percentage of Schwann cells containing typical CBs, which concentrate spliceosomal snRNPs and the survival motor neuron (SMN) protein. This increase in the number of CBs closely correlates with the activation of transcription. Moreover, the occurrence of CBs is significantly higher in BrdU (+) cells than in BrdU (−) cells, indicating that entry in the S phase promotes the formation of CBs. During the S phase, Schwann cell nuclei display higher Cdk2 nuclear staining and concentrate this kinase in CBs. Forskolin also induces a redistribution of the pre‐mRNA splicing factors in Schwann cells. Primary cultures of Schwann cells provide an excellent physiological model to demonstrate that the assembly of CBs is a transcription‐ and replication‐dependent cellular event. Moreover, the S phase accumulation of Cdk2 observed in Schwann cells supports a functional link between CBs and DNA replication, which is mediated by the possible participation of CBs in the regulatory control of histone gene expression. GLIA 40:378–388, 2002. © 2002 Wiley‐Liss, Inc.
Structure of the tarsi in some stenus species (coleoptera, staphylinidae): External morphology, ultrastructure, and tarsal secretion
Authors: Betz Oliver
Published: November 2002

SEM studies show that the differentiation among Stenus species with respect to the formation of the tarsi (wide bilobed vs. slender tarsomeres) takes place with a considerable augmentation of tarsal ventral setae in wide bilobed tarsomeres. The structural diversity of ventral tarsal setae among and within species is discussed with respect to 1) their different roles as mechanosensilla and tenent setae, respectively, and 2) the different selection pressures in terms of adhesive requirements along the longitudinal tarsus axis. The tarsi are provided with four groups of tarsal mechanosensilla, comprising hair and bristle sensilla, campaniform sensilla, and scolopidia. The tarsus wall is supported by an epidermis, which forms three different types of glands pouring their secretion via different exit paths onto the outer cuticle. The organization and ultrastructure of each of these glands is described. Only one (unicellular) gland is directly associated with the ventral tenent setae and is thus considered to form the main part of the adhesive secretion. The beetles appear to release the tarsal secretion through mediation of the tenent setae, which contains a lipid and a proteinaceous fraction. I propose that the secretion is discharged to the outside via a system of very fine pore canals in the wall of the setal shaft. Gas chromatography and infrared spectroscopy revealed that the lipid fraction of the secretion is a mixture of unsaturated fatty acid glycerides and aliphatic hydrocarbons whose spectra are similar to those of extractions of the superficial lipid coating of the body surface. J. Morphol. 255:24–43, 2003. © 2002 Wiley‐Liss, Inc.
Development of the supraorbital and mandibular lateral line canals in the cichlid, archocentrus nigrofasciatus
Authors: Tarby Melissa L. , Webb Jacqueline F.
Published: November 2002

The development of two of the cranial lateral line canals is described in the cichlid, Archocentrus nigrofasciatus. Four stages of canal morphogenesis are defined based on histological analysis of the supraorbital and mandibular canals. “Canal enclosure” and “canal ossification” are defined as two discrete stages in lateral line canal development, which differ in duration, an observation that has interesting implications for the ontogeny of lateral line function. Canal diameter in the vicinity of individual neuromasts begins to increase before ossification of the canal roof in each canal segment; this increase in canal diameter is accompanied by an increase in canal neuromast size. The mandibular canal generally develops later than the supraorbital canal in this species, but in both of these canals development of the different canal segments contained within a single dermal bone is asynchronous. These observations suggest that a dynamic process requiring integration and interaction among different tissues, in both space and time, underlies the development of the cranial lateral line canal system. The supraorbital and mandibular canals appear to demonstrate a “one‐component” pattern of development in Archocentrus nigrofasciatus, where the walls of each canal segment grow up from the underlying dermal bone and then fuse to form the bony canal roof. This is contrary to numerous published reports that describe a “two‐component” pattern of development in teleosts where the bony canal ossifies separately and then fuses with an underlying dermal bone. A survey of the literature in which lateral line canal development is described using histological analysis suggests that the occurrence of two different patterns of canal morphogenesis (“one‐component” and “two‐component”) may be due to phylogenetic variation in the pattern of the development of the lateral line canals. J. Morphol. 255:44–57, 2003. © 2002 Wiley‐Liss, Inc.
Complex genital structures indicate cryptic female choice in a haplogyne spider (arachnida, araneae, oonopidae, gamasomorphinae)
Authors: Burger Matthias , Nentwig Wolfgang , Kropf Christian
Published: November 2002

Female genital structures with their allied muscles of the haplogyne spider Opopaea fosuma are described. A functional explanation of this system is given, which indicates that cryptic female choice may occur in these spiders: the anterior wall of their spermatheca is strongly sclerotized and possesses a cone‐shaped hole in its upper part. A transverse sclerite that serves as muscle attachment bears a nail‐like structure and lies in a chitinized area of the anterior wall of the uterus externus. Muscle contraction presses this nail into the hole of the spermatheca. In this way, the uterus externus gets both locked and fixed. Furthermore, as this occurs the copulatory orifice is enlarged and the resulting suction probably leads to previously deposited sperm being drawn from the spermatheca and dumped. This is a common mechanism used by females to influence a male's chances of fathering their offspring in a process known as cryptic female choice. J. Morphol. 255:80–93, 2003. © 2002 Wiley‐Liss, Inc.
Cranial osteology of the andean lizardstenocercus guentheri(Squamata: Tropiduridae) and its postembryonic development
Authors: Torres‐Carvajal Omar
Published: November 2002

In spite of the great diversity of iguanian lizards, detailed descriptions of their osteocrania and postembryonic development are rare. Herein, the adult cranial osteology of the tropidurid lizardStenocercus guentheriand its postembryonic development are described based on cleared and double‐stained and dry skeletal specimens from a single Ecuadorian population. The amphikinetic skull ofS. guentheriis short and elevated and bears teeth on the premaxilla, maxillae, and pterygoids. Mandibular teeth are present on the dentaries. Ossification of the articular from Meckel's cartilage and growth of the parietal (ossification and investment of the frontoparietal fontanelle) are the most significant ontogenetic changes of the splanchnocranium and dermatocranium, respectively. The ossification of the cartilage separating the bones of the braincase is the most relevant postembryonic ontogenetic event of the neurocranium. The number of teeth does not vary ontogenetically and replacement teeth are present throughout postembryonic life. This study includes a list of the osteocranial characters ofStenocercusthat have been used in systematic studies, as well as a discussion of functional morphology and kinesis. J. Morphol. 255:94–113, 2003. © 2002 Wiley‐Liss, Inc.
Developmental origin of the frontoparietal bone in bombina variegata (anura: discoglossidae)
Authors: Čihák Radomír , Královec Karel , Roček Zbyněk
Published: November 2002

Development of the frontoparietal bone in the European yellow‐bellied toad, Bombina variegata, was followed on the basis of histological analysis of transverse serial sections through the larval skulls to recognize early stages of ossification represented by osteoid (uncalcified bone matrix) and on cleared and stained specimens to investigate more advanced stages. Ossification of the frontal begins as three tiny areas of osteoid (F1, F2, F3) adjoining the dorsal surface of the orbital cartilage, which are separated by areas without osteoid. F3 is the largest (most advanced). Prior to calcification, F3 extends to fuse with F2 and then with F1, but it does not expand over the prootic fissure posteriorly. As calcification begins the strip of bone is joined posteromedially by F4. Only then does a single ossification center corresponding to the parietal arise on the anterodorsal surface of the otic capsule. This ossification sequence corresponds to those observed in the Actinopterygii and in caudate amphibians. J. Morphol. 255:122–129, 2003. © 2002 Wiley‐Liss, Inc.
Application service providers (ASPs): new impetus for transformational change
Authors: Kakabadse Andrew , Kakabadse Nada
Published: November 2002

Application service providers (ASPs) are a business phenomenon of the Internet age. The ASP concept offers companies the rewards of best‐in‐class application functionality for a fixed monthly cost and easy usage scalability, thus liberating organizations from technological complexities. In exploring the effectiveness of the ASP model, this paper examines the development of ASPs and also reports the results of a UK study, 178 ASP service purchasers and providers, highlighting the nature and offerings of service providers and the levels of satisfaction with ASP services. It is argued that the ASPs' potential to induce transformational change in terms of business processes and thus on the total enterprise is extensive. Also, by highlighting concerns with current ASP services, the paper concludes on an optimistic note emphasizing a favourable outlook for ASPs in the future. Copyright © 2002 John Wiley & Sons, Ltd.
Developing a model for technology and cultural factors in knowledge management: a factor analysis
Authors: Moffett Sandra , McAdam Rodney , Parkinson Stephen
Published: November 2002

Continual development in the field of Knowledge Management (KM) has led to a number of critical factors being highlighted in the literature. These issues include the macro‐environment, organizational climate, technological, informational, cultural and people factors. Understanding of these issues is currently limited by a paucity of systematic empirical research addressing the relationship between the cultural and technological aspects of Knowledge Management. This paper describes the development of a conceptual model for Knowledge Management implementation, which is based on a university/industry partnership and a successful PhD study. Moreover, the paper covers theory‐testing and refinement of the model using large survey empirical analysis. It is concluded that the model can be used across a wide spectrum of organizations to show how cultural and technological aspects of Knowledge Management can be systematically integrated into organizations. Copyright © 2002 John Wiley & Sons, Ltd.