bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of vascular endothelial growth factor (VEGF)A and VEGFB gene transfer on vascular reserve in a conscious rabbit hindlimb ischaemia model
Authors: Wright Christine E
Published: March 2003

1. As a result of the ageing population, there are increasing numbers of patients with severe peripheral vascular occlusive disease associated with intermittent claudication (pain on walking) and decreased exercise tolerance. There is a great clinical need for pharmacological treatments that may stimulate collateral blood vessel growth, increase vascularity and improve skeletal muscle function.

2. Therapeutic angiogenesis using growth factors such as vascular endothelial growth factor (VEGF) has been used to improve collateral artery development in myocardial or skeletal muscle ischaemia. The broad aims of the work briefly summarized here were to compare the effects of VEGFA165 and VEGFB167 (500 µg, i.m., gene transfer) on calf blood pressure ratio and reactive hyperaemia in a chronic rabbit preparation with unilateral limb ischaemia.

3. Unilateral femoral artery ligation caused an immediate deficit (compared with the contralateral limb) of 72% in calf systolic blood pressure. There were improvements 14 days after ligation with VEGFA and VEGFB treatments compared with the vehicle control plasmid treatment, but a deficit remained of some 32%.

4. Reactive hyperaemic responses were significantly attenuated 7 days after ligation in the vehicle and VEGFA treatment groups. On day 14, this loss of vascular reserve was restored in the VEGFA group, but remained in the vehicle group (−30%). In VEGFB‐treated animals, there was no deficit in reserve 7–14 days post‐ligation.

5. In conclusion, there is considerable value in the serial measurements of calf blood pressure ratio and reactive hyperaemia in the rabbit unilateral hindlimb ischaemia model. Gene transfer of either VEGFA or VEGFB allowed significant improvements in these indices compared with vehicle but, at 14 days post‐ligation, large deficits still remained. Studies extending this experimental period are in progress.
Effects of polarizing solution on glucose uptake of rat oxygenated or hypoxic ventricular myocytes
Authors: Carbó Roxana , Nava Pilar , Guarner Verónica
Published: March 2003

1. Although adult cardiac metabolism depends on fatty acids rather than on carbohydrates, hypoxic hearts consume glucose and infusion with a glucose–insulin–potassium solution (GIK) helps in the recovery of the pressure register, the heart rate and electrocardiogram of rat hypoxic whole hearts.

2. Rat myocytes obtained by enzymatic disaggregation captured significant amounts of glucose in Tyrode's solution (9.8 ± 2.05% during oxygenation and 16.26 ± 2.76% during hypoxia) after 60 min incubation. Cells incubated with GIK showed a significantly increased glucose uptake (to 30.04 ± 1.99% during oxygenation and to 37.06 ± 1.97% during hypoxia).

3. Glucose was the component of the Tyrode's solution that most enhanced its own entry, increasing glucose entry to 45.42 ± 2.64% with oxygen and 41.42 ± 2.69% under hypoxia.

4. Antibodies against glucose transporters 1 and 4 (GLUT‐1 and ‐4, respectively) decreased glucose transport during GIK treatment under hypoxia.

5. We conclude that GIK has beneficial effects mediated by GLUT‐1 and ‐4 during hypoxia, inducing recovery of the damaged tissue.
Restoration of osmotically inhibited twitch force in rat cardiac trabeculae: Role of Na+–H+ exchange
Authors: Cropper JRD , Erac I , Loiselle DS
Published: March 2003

1. When rat cardiac muscle is subjected to an increase of osmolality, its peak twitch force is immediately inhibited. Subsequently, over a period of several minutes, twitch force undergoes restoration, the extent of which is determined by the osmolality. The aim of the present study was to determine the factors that contribute to this restorative phenomenon.

2. Trabeculae were isolated from the right ventricles of rat hearts and mounted in an organ bath at 37°C. The osmolality of the bathing solution was increased by 100 mOsmol (to 400 mOsmol) by the addition of various proportions of NaCl and sucrose while recording twitch force production. The role of Na+–H+ exchange in restoring twitch force was examined by use of the specific inhibitor cariporide (HOE 642). The role of Na+–Ca2+ exchange was examined by reducing [Ca2+]o (from 2 mmol/L to 0.5 mmol/L) or by substituting LiCl for NaCl.

3. Cariporide (25 µmol/L) completely abolished twitch force restoration, thereby implicating a central role for the Na+–H+ exchanger. At constant [Na+]o, the extent of restoration was [Ca2+]o dependent, suggesting an independent contribution by the Na+–Ca2+ exchanger. This suggestion was supported by the finding that Li+, which substitutes for Na+ on the Na+–H+ exchanger, but not on the Na+–Ca2+ exchanger, also reduced the extent of restoration of hyperosmotically inhibited twitch force.

4. We conclude that the immediate inhibition of peak twitch force of rat cardiac muscle by hyperosmotic solutions reflects, in part, elevation of [H+]i, subsequent to reduction of cell volume. Hyperosmotic activation of Na+–H+ exchange then progressively relieves the inhibitory effect of protons on force development. The accompanying increase in [Na+]i in turn enhances Ca2+ influx on the Na+–Ca2+ exchanger, with the result that twitch force undergoes further restoration.
Inhibition of nuclear translocation of transcription factor nuclear factor‐κB induces FAS‐ as well as tumour necrosis factor‐α‐mediated apoptosis through downregulation of a conserved family of inhibitor of apoptosis 1
Authors: Imanishi Toshio , Hano Takuzo , Takarada Shigeho , Nishio Ichiro
Published: March 2003

1. In the present study, we examined whether the nuclear transcription factor (NF)‐κB activity plays a role in the determination of sensitivity to tumour necrosis factor (TNF)‐α or agonistic Fas antibody (Ab) in human vascular smooth muscle cells (hVSMC).

2. To inhibit agonist‐induced NF‐κB activation in hVSMC, a cell‐permeable peptide (SN50), which carried the nuclear localization sequence of the NF‐κB p50 subunit, was used. Nuclear factor‐κB activity was examined by both immunoblot analysis of nuclear extracts and by ELISA. The hVSMC were treated with TNF‐α or agonistic Fas Ab (CH11) and then apoptosis was determined by cell death ELISA for DNA fragmentation. To investigate the mechanisms for protection against apoptosis in hVSMC, we analysed the expression of a conserved family of inhibitor of apoptosis 1 (c‐IAP1) protein using immunoblot analysis.

3. Although both CH11 and TNF‐α alone failed to induce hVSMC death in the presence of SN50, they markedly increased the apoptotic hVSMC estimated by cell death ELISA. In addition, these effects could be blocked with the pan‐caspase inhibitor z‐VAD.fmk. Western blotting analysis indicated that TNF‐α alone increased c‐IAP1 protein levels, whereas CH11 alone had no effect. Inhibition of NF‐κB activation by SN50 suppressed c‐IAP1 protein expression and enhanced apoptosis induced by either TNF‐α or CH11.

4. These findings suggest that c‐IAP1 is an important intracellular modulator of Fas as well as TNF‐α death signalling pathways in hVSMC. The expression of c‐IAP1 is regulated by a NF‐κB‐mediated phenomenon.
Validation of a portable indirect calorimeter (Metavine®) for measuring energy expenditure in an elderly population
Authors: Kato Masahiko , Tajika Masahiro , Miwa Yoshiyuki , Moriwaki Hisataka
Published: March 2003

1. The aim of the present study was to evaluate the usefulness and reliability of a portable indirect calorimeter (Metavine; Vine, Tokyo, Japan).

2. We measured energy expenditure (EE) of elderly people (n = 191) at nursing homes using both Metavine and an authorized indirect calorimeter (Deltatrac Metabolic Monitor; Datex, Helsinki, Finland) and compared them.

3. Energy expenditure measured by Metavine® significantly correlated with EE measured by the Deltatrac Metabolic Monitor (P < 0.001).

4. In particular, Metavine gave almost same results as the Deltatrac Metabolic Monitor, showing an excellent reliability, within the range of EE from 800 to 1500 kcal/day. However EE measured by Metavine below 800 kcal/day or above 1500 kcal/day required correction to agree with EE as measured by the Deltatrac Metabolic Monitor.

5. In conclusion, Metavine is a useful portable calorimeter for measuring EE in elderly people when used with sufficient recognition of its characteristics of data acquisition.
Studies on heat shock proteins in sea urchin development
Authors: Giudice Giovanni , Sconzo Gabriella , Roccheri Maria Carmela
Published: March 2003

Work on stress proteins in sea urchin embryos carried out over the last 20 years is reviewed and the following major results are described. Entire sea urchin embryos, if subjected to a rise in temperature at any postblastular stage undergo a wave of heat shock protein (hsp) synthesis and survive. If subjected to the same rise between fertilization and blastula formation, they are not yet able to synthesize hsp and die. Four clones coding for the major hsp, hsp70, have been isolated and sequenced; evidence for the existence of a heat shock factor has been provided, and a mechanism for the developmental regulation of hsp synthesis discussed. Intra‐ embryonic and intracellular hsp location has been described; and a mechanism for achievement of thermotolerance proposed. A chaperonine role for a constitutive mitochondrial hsp56 has been suggested, as well as a role for the constitutive hsp70 in cell division. Heat shock, if preceded by 12‐O‐tetradecanoylphorbol‐12‐acetate (TPA) treatment causes apoptosis.
Analysis of the origin and development of hatching gland cells by transplantation of the embryonic shield in the fish, Oryzias latipes
Authors: Inohaya Keiji , Yasumasu Shigeki , Yasumasu Ikuo , Iuchi Ichiro , Yamagami Kenjiro
Published: March 2003

Hatching gland cells of the medaka, Oryzias latipes, have been observed to differentiate from the anterior end of the hypoblast, which seems to first involute at the onset of gastrulation. These results suggest that the hatching gland cells of medaka originate from the embryonic shield, the putative organizer of this fish. The present study investigated whether hatching gland cells really originate from the embryonic shield in the medaka. Transplantation experiments with embryonic shield and in situ hybridization detection of hatching enzyme gene expression as a sign of terminal differentiation of the gland cells were carried out. The analysis was performed according to the following processes. First, identification and functional characterization of the embryonic shield region were made by determining the expression of medaka goosecoid gene and its organizer activity. Second, it was confirmed that the embryonic shield had an organizer activity, inducing a secondary embryo, and that the developmental patterns of hatching gland cells in primary and secondary embryos were identical. Finally, the hatching gland cells as identified by hatching enzyme gene expression were found to coincide with the dye‐labeled progeny cells of the transplanted embryonic shield. In conclusion, it was determined that hatching gland cells were derived from the embryonic shield that functioned as the organizer in medaka.
Fine structure of micropylar region during late oogenesis in eggs of the hagfish Eptatretus burgeri (Agnatha)
Authors: Morisawa Sachiko
Published: March 2003

Using the hagfish, Eptatretus burgeri, the fine structure of formation of the micropylar region in hagfish eggs during the late stages of oogenesis was investigated for the first time, focusing on the bottom region of the micropyle and the egg surface. During these stages, many cells penetrated through the chorion and reached a pit of the egg surface, forming a shovel‐like structure in two‐dimensional sections. The cells, which we called micropylar cells, were separated from the chorion by a wall of amorphous material. In the pit, another fibrous layer filled the space between the egg surface and the anterior portion of the shovel‐like structure. Microvilli coming from the egg surface were embedded in this layer. In later stages, the stack of micropylar cells loosened, and a space appeared between the anterior region of the shovel‐like structure and the layer on the egg surface. Microvilli decreased in length and number. The pit region appeared likely to have a role in fertilization. The structures associated with the forming micropyle were markedly different from those observed in the same region of teleost fishes. A hypothesis that hagfish might show transitional structures in gametes from protochordates to teleosts is suggested.
Stress‐induced phenocopy of C. elegans defines functional steps of sensory organ differentiation
Authors: Chow King Lau , Chan Kwok Wai
Published: March 2003

The differentiation of male specific sensory rays in the nematode Caenorhabditis elegans is a complex process regulated by multiple genetic components. A novel approach with heat shock treatment was employed to show that multistep regulation is involved in this process. Intervention in this stepwise regulation resulted in phenocopy of specific gene mutations. The results suggest that differential gene function acting at a precise time frame is necessary to guide the normal differentiation of sensory rays.
Cell fate analysis of teloblasts in the Tubifex embryo by intracellular injection of HRP
Authors: Goto Asako , Kitamura Kaoru , Arai Asuna , Shimizu Takashi
Published: March 2003

As in other clitellate annelids, embryonic development in the oligochaete Tubifex is characterized by the generation of five bilateral pairs of teloblasts (designated M, N, O, P and Q), which serve as embryonic stem cells to produce germ bands on either side of the embryo. A large part of the tissues comprising body segments has been assigned to the progenies of the teloblasts; however, the developmental fate of each teloblast has been inferred only from its initial position in the embryo. In the present study, the fate of the progenies of each teloblast was followed by means of intracellular injection of a tracer enzyme, horseradish peroxidase. Cell fate maps for teloblasts in the Tubifex embryo were constructed. M teloblasts gave rise to nearly all of the mesodermal tissues, which included circular and longitudinal muscles, coelomic walls, nephridia (in segments VII and VIII) and primordial germ cells (in segments X and XI). Although few in number, M teloblasts also contributed cells to the ventral ganglion. Similarly, each of the ectoteloblasts, N, O, P and Q, made a topographically characteristic contribution to the ectodermal tissues such as the nervous system (i.e. ganglionic cells and peripheral neurones) and epidermis, all of which exhibited a segmentally repeated distribution pattern. The P and Q teloblasts uniquely gave rise to additional ectodermal tissues, namely ventral and dorsal setal sacs, respectively. Furthermore, O teloblasts made a contribution to the nephridiopores in segments VII and VIII as well. These results confirm the previously held view that ectoteloblasts and mesoteloblasts are the main source of ectodermal and mesodermal segmental tissues, respectively, but also suggest that all of the teloblasts produce more types of tissue than has previously been thought.
Expression of five novel T‐box genes and brachyury during embryogenesis, and in developing and regenerating limbs and tails of newts
Authors: Sone Kiyoaki , Takahashi Tadashi C. , Takabatake Yuka , Takeshima Kazuhito , Takabatake Takashi
Published: March 2003

Several T‐box genes are considered to play important roles in developing limbs, tails and neural retinae. Five novel T‐box genes in the Japanese newt were isolated and their expression was analyzed, together with another T‐box gene of brachyury, during embryogenesis and in the developing and regenerating limbs and tail. Four are designated CpTbx2, CpTbx3, CpTbx6R and CpEomesodermin based on molecular phylogenetic analyses, and the other is named CpUbiqT from its ubiquitous expression. While all were expressed during embryogenesis, only four of them (CpTbx2, CpTbx3, CpUbiqT and brachyury) were detected in developing limbs and/or tails. Except for brachyury, they were continuously expressed in normal adult appendages and showed elevated expression levels in regenerating limbs, whereas only CpTbx2 showed significant up‐regulation in regenerating tails. Compared with orthologous genes in other species, CpTbx2, CpTbx3 and CpEomesodermin showed several notable differences such as an abundance of maternal transcripts of CpEomesodermin, a unique insertion sequence within the T‐box domain of CpTbx2, and a lack of visible expression of CpTbx2 and CpTbx3 in the apical ectodermal region of developing limbs. In view of the uniqueness of the newt, these results are discussed with respect to the possibility of their involvement in regeneration.
Real‐time observation of transplanted ‘green germ cells’: Proliferation and differentiation of stem cells
Authors: Ohta Hiroshi , Yomogida Kentaro , Yamada Shuichi , Okabe Masaru , Nishimune Yoshitake
Published: March 2003

To elucidate the mechanism of proliferation and differentiation of testicular germ cells, donor testicular germ cells labeled with enhanced green fluorescent protein (eGFP) were transplanted to recipient seminiferous tubules. The kinetics of colonization as well as of differentiation of the donor cells was followed in the same transplanted tubules (alive) under ultraviolet light. One week after transplantation, clusters of fluorescent cells were randomly spread as dots in the recipient seminiferous tubule, whereas non‐homed cells flowed out from the testis to the epididymis. By 4 weeks after transplantation, green germ cells were observed with weak and moderate fluorescence along the recipient seminiferous tubule. By 8 weeks, proliferation and differentiation of the germ cells occurred, resulting in strong fluorescence in the middle part of the seminiferous tubule but in weak and moderate fluorescence at both terminals. The length of the fluorescent positive seminiferous tubule became longer. Detailed histological analyses of the recipient tubules indicated that the portions of the seminiferous tubule in weak, moderate, and strong fluorescence contained the spermatogonia, spermatogonia with spermatocytes, and all types of germ cells including spermatids, respectively. Thus, testicular stem cells colonized first as dots within 1 week, and then proliferated along the basement membrane of the seminiferous tubules followed by differentiation.
Expression and characterization of Xenopus type I collagen alpha 1 (COL1A1) during embryonic development
Authors: Goto Toshiyasu , Katada Tomohisa , Kinoshita Tsutomu , Kubota Hiroshi Y.
Published: March 2003

A cDNA encoding Xenopus type I collagen alpha 1 (Xenopus COL1A1) has been isolated from an ovary cDNA library. The COL1A1 cDNA is approximately 5.7 kb pairs and encodes 1447 amino acids. The putative COL1A1 polypeptide shares high identities of amino acid sequence with other vertebrate COL1A1 proteins. The level of Xenopus COL1A1 transcripts was increased markedly in the posterior region of the embryo at the tail‐bud stage, then gradually spread to the anterior region. Histological observations of the tail‐bud embryos showed that COL1A1 was mainly expressed in the inner layer of the posterior dorsal epidermis exposed to the somite mesoderm, except for in the dorsal fin. Less intense signals were also detected in the outer layer of the dorsal epidermis and dermatome. The expression of COL1A1 was increased in posteriorized embryos resulting from treatment with retinoic acid but decreased in hyper‐dorsalized embryos resulting from lithium chloride treatment. These results suggest that COL1A1 is a major component of the dorsal dermis exposed to the somite in Xenopus embryos, but its expression is not related to the temporal sequence of somite segregation.
Initial analysis of immunochemical cell surface properties, location and formation of the serotonergic apical ganglion in sea urchin embryos
Authors: Yaguchi S. , Kanoh K. , Amemiya S. , Katow H.
Published: March 2003

In the present study it was found that serotonergic apical ganglion (SAG)‐forming cells in plutei of the sea urchin, Hemicentrotus pulcherrimus, possessed a characteristic pear shape with broad apical sides and a pointed basal side in the acron epithelium. The basal side extended axons through the space between the epithelium and the basal lamina toward the midline of the embryo that aligned parallel to the embryonic anteroposterior axis. Serotonergic apical ganglion‐forming cells had epithelial cell surface‐specific proteins on their entire surface. The SAG in 4‐arm plutei was composed of a 4‐cell trunk region that aligned at right angles to the embryonic anteroposterior axis, and forked into two branches of one to two cells at both ends. Two branches extended toward the oral and the other two toward the aboral region, respectively. Double‐stained immunohistochemistry using antiserotonin antibodies and oral ectoderm‐specific anti‐Ecto V monoclonal antibody or aboral ectoderm‐specific anti‐Ars antibodies indicated that SAG was in the aboral ectoderm region. Serotonergic apical ganglion cells were first detected in late gastrulae and increased in number rapidly between 36 and 48 h after fertilization, and then slowly afterwards. A 5‐bromo‐2‐deoxyuridine incorporation study indicated that none of the increased SAG cells were in the S phase during the aforementioned period, suggesting that SAG cells do not proliferate by cell division, but acquire the property in particular cells by transdifferentiation using a mechanism that has yet to be elucidated.
Primary structure and developmental expression of Bufo arenarum cellular nucleic acid‐binding protein: Changes in subcellular localization during early embryogenesis
Authors: Armas Pablo , Cabada Marcelo Oscar , Calcaterra Nora Beatriz
Published: March 2003

A Bufo arenarum cellular nucleic acid‐binding protein (bCNBP) full‐length cDNA was cloned. bCNBP is a 19.4 kDa protein containing seven CCHC zinc finger motifs, an RGG box and a Ser‐rich region. Amino acid comparisons showed high values of homology in vertebrates and smaller values in insects or inferior eukaryotes. Northern blot analysis during oogenesis and early development revealed two transcripts with different expressions of pattern behavior. One of them is present in all stages analyzed, whereas the other is only detected from the beginning of zygotic transcription. Immunocytochemistry assays carried out on sections of ovary and early embryos showed that there was no specific staining of previtellogenic oocytes. In early vitellogenic oocytes, in oocytes at stages V/VI and in embryos at early blastula stage, reaction was observed inside the cytoplasm. At mid‐blastula stage, CNBP was mainly detected in the epiblast. At the late gastrula stage, two layers of cells were stained in the archenteron roof, in which the internal one presented as strong staining. Nuclei in this layer were stained even stronger than the cytoplasm. Changes in mRNA expression patterns, accompanied by changes in subcellular localization, suggest that CNBP might interact with both nuclear and cytoplasmic nucleic acids.
Possible role for the c‐ski gene in the proliferation of myogenic cells in regenerating skeletal muscles of rats
Authors: Soeta Chie , Suzuki Michio , Suzuki Shunichi , Naito Kunihiko , Tachi Chikashi , Tojo Hideaki
Published: March 2003

Skeletal muscle regeneration after injury involves various processes, such as infiltration by inflammatory cells, the proliferation of satellite cells and fusion to myotubes. The c‐ski nuclear protein has been implicated in the control of cell proliferation and/or terminal differentiation in the growth of skeletal muscle. However, there have been no reports concerning the involution of c‐ski in the regeneration of injured skeletal muscle in mammals. A possible role for c‐ski in the proliferation of myogenic cells in rat skeletal muscle during regeneration has been investigated with the assistance of in vitro experiments with L6 skeletal muscle cells. The expression levels of c‐ski mRNA in regenerating tissues increased to approximately threefold that of intact tissues at 2 days after injury and decreased to normal levels at 2 weeks after injury. Many mononuclear cells among the Ski‐positive cells expressed desmin and proliferating cell nuclear antigen, indicating that Ski‐producing cells include the proliferating myogenic cells. The proliferation of L6 cells was significantly retarded by expression of the antisense ski gene. The results of the present study reveal that the c‐ski gene plays an important role in the proliferation of myogenic cells in the regeneration of injured skeletal muscle.
A novel putative transmembrane protein, IZP6, is expressed in neural cells during embryogenesis
Authors: Tsukahara Masatoshi , Ji Zai‐Si , Noguchi Shigeru , Tsunoo Hajime
Published: March 2003

Gene trapping in mouse embryonic stem cells is an efficient method for identifying new genes and examining their functions. This method has been used in an effort to identify some novel genes involved in mouse development. In the present paper, one such gene named IZP6 is reported. Expression of the IZP6 gene, as monitored by β‐galactosidase expression in heterozygous mice, was detected in a developmentally regulated fashion: the expression pattern has two phases during the embryogenesis. In the first phase, from embryonic day 11.5 (E11.5) until E14.5, the reporter gene is mainly expressed in the forebrain. In the second phase, from E15.5 until birth, expression in the forebrain becomes weaker but is still observed in the olfactory bulb and the skin around the eyes, nose, limbs and tail. Thus, IZP6 gene expression changes from the central nervous system (the first phase) to the peripheral tissues (the second phase) during development. The IZP6 gene encodes a protein of 228 amino acids. Analysis of the secondary structure of the IZP6 protein revealed four hydrophobic regions, indicating that the IZP6 protein is a four transmembrane region protein. These results suggest that IZP6 is a transmembrane protein related to neurogenesis in the mouse..
Possible roles of β‐catenin in evagination of the optic primordium in rat embryos
Authors: Matsuda Motoko , Keino Hiroomi
Published: March 2003

The roles of β‐catenin in evagination of the optic primordium in rat embryos were studied using immunostaining. High levels of β‐catenin appeared transiently in the evaginating optic primordium. Evagination of the optic primordium was suppressed in embryos treated with LiCl. In deficient optic vesicles of these embryos, accumulation of β‐catenin was decreased. Deficient optic vesicles also showed suppression of cyclin D1 accumulation and bromodeoxyuridine incorporation, no break in the deposition of laminin and type IV collagen at the basement membrane (BM) and prevention of the change in distribution of microtubles and microfilaments. These results suggest that β‐catenin regulates cell proliferation, breakdown of BM and changes in cell shape in the evaginating optic primordium to cause optic vesicle formation..
Evolution of larval form in the sea star genus Patiriella: Conservation and change in the larval nervous system
Authors: Byrne Maria , Cisternas Paula , Koop Demian
Published: March 2003

The organization of the peptidergic system in the larvae of Patiriella species with divergent ontogenies was compared to determine which aspects of neurogenesis are conserved and which are altered in the evolution of development in these sea stars. P. regularis has ancestral‐type feeding bipinnaria and brachiolaria larvae and the organization of the nervous system, in association with feeding structures, paralleled the bilateral larval body plan. P. calcar and P. exigua have non‐feeding planktonic and benthic brachiolariae, respectively, and there was no trace of the neuronal architecture involved with feeding. The nervous system in the attachment stage brachiolaria was similar in all three species and neuronal organization reflected larval symmetry. Delayed expression of peptidergic lineages to the brachiolaria stage in the lecithotrophs indicates heterochronic change in the timing of neurogenesis or deletion of the ancestral early neurogenic program. The bipinnarial program is suggested to be a developmental module autonomous from the brachiolar one. With a divergence time of less than 10 Ma, the evolution of development in Patiriella has resulted in extensive reduction in the complexity of the larval nervous system in parallel with simplification in larval form. There is, however, strong conservation in the morphology and neuronal architecture of structures involved with settlement.
Volvox carteri as a model for studying the genetic and cytological control of morphogenesis
Authors: Kirk David L. , Nishii Ichiro
Published: March 2003

The green alga Volvox carteri has a very simple and regular adult form that arises through a short sequence of well‐defined morphogenetic steps. A mature gonidium (asexual reproductive cell) initiates a stereotyped sequence of rapid cleavage divisions that will produce all of the cells found later in an adult. A predictable subset of these divisions are asymmetric and result in production of a small set of germ cells in a precise spatial pattern. Throughout cleavage, all intracellular components are held in predictable spatial relationships by a cytoskeleton of unusually regular structure, while neighboring cells are also held in fixed spatial relationships by an extensive network of cytoplasmic bridges that form as a result of incomplete cytokinesis. As a result of these two orienting mechanisms combined, dividing cells are arranged around the anterior–posterior axis of the embryo with precise rotational symmetry. These relationships are maintained by the cytoplasmic bridge system when the embryo that was inside out at the end of cleavage turns right‐side out in the gastrulation‐like process of inversion. Inversion is driven by a cytoskeleton‐mediated sequence of cell shape changes, cellular movements and coordinated contraction. Then, by the time the cytoplasmic bridges begin to break down shortly after inversion, a preliminary framework of extracellular matrix (ECM) has been formed. The ECM traps the cells and holds them in the rotational relationships that were established during cleavage, and that must be maintained in order for the adult to be able to swim. Transposon tagging is now being used to clone and characterize the genes regulating these morphogenetic processes.
Two cell‐counting factors regulate the aggregate size of the cellular slime mold Dictyostelium discoideum
Authors: Okuwa Takako , Katayama Takahiro , Takano Akinori , Kodaira Ken‐ichi , Yasukawa Hiroo
Published: March 2003

Countin, a cell‐counting factor in Dictyostelium discoideum, is considered to limit the maximum size of the multicellular structure, because a countin null strain forms a huge fruiting body compared to that of the wild‐type. A novel gene, countin2, that is highly homologous to countin (40% identity in amino acid sequence) was identified in the D. discoideum genome. The countin2 null strain formed a 1.7‐fold higher number of the aggregates, resulting in smaller fruiting bodies compared with those of wild‐type cells. Thus, the Countin2 protein is thought to limit the minimum size of the multicellular structure. The size and number of aggregates formed by a mixture of countin null and countin2 null strains were the same as those of the wild‐type. These findings demonstrate that a combination of Countin and Countin2 proteins determines the appropriate size of the multicellular structure of D. discoideum.
Studies on fertilization in the teleost IV. Effects of aphidicolin and camptothecin on chromosome formation in fertilized medaka eggs
Authors: Iwamatsu Takashi , Shibata Yasushi , Hara Osamu , Yamashita Masakane , Ikegami Susumu
Published: March 2003

To clarify the mechanisms of fish fertilization, the effects of inhibitors of DNA polymerase‐α and DNA topoisomerases on nuclear behavior before and after fertilization were examined in eggs of the medaka, Oryzias latipes. Eggs underwent the fertilization process from sperm penetration to karyogamy of pronuclei, even when inseminated and incubated in the continuous presence of aphidicolin (DNA polymerase α inhibitor), camptothecin (DNA topoisomerase I inhibitor), etoposide, or β‐lapachone (DNA topoisomerase II inhibitor). However, continuous treatment with aphidicolin or camptothecin during fertilization inhibited the formation of sister chromosomes that were normally separated into blastomeres at the time of the subsequent cleavage. Sister chromosome formation appeared concomitantly with an increase in histone H1 kinase activity at the end of DNA synthesis, 30 min post insemination. However, non‐activated eggs that were inseminated in saline containing anesthetic MS222 and aphidicolin had high levels of histone H1 kinase and MAP kinase activities, and transformation of the penetrated sperm nucleus to metaphase chromosomes occurred even in the presence of aphidicolin or camptothecin. The male chromosomes were normally separated into two anaphase chromosome masses upon egg activation. These results suggest that DNA polymerase α or DNA topoisomerase I, but not DNA topoisomerase II, may be required for the process by which the mitotic interphase nucleus transforms to separable metaphase chromosomes while the activity of MAP kinase is low, unlike the situation in meiotic division, during which MAP kinase activity is high and DNA replication is not required.
Comparison of growth habits under various light conditions between two climax species, Castanopsis sieboldii and Castanopsis cuspidata, with special reference to their shade tolerance
Authors: Hiroki Shozo , Ichino Kazuo
Published: March 2003

Two experiments were conducted to examine the difference in shade tolerance between two climax species, Castanopsis sieboldii and Castanopsis cuspidata, in Aichi Prefecture in the warm‐temperate climate of Japan. In the growth experiment, the seedlings of the two species were raised under five light conditions, 100%, 30%, 10%, 3% and 1% relative light intensity (RLI). The growth of C. sieboldii highly exceeded that of C. cuspidata, particularly under higher light conditions. In the heavy shading experiment, the seedlings of the two species were grown under three light conditions (0, 0.15 and 0.3% RLI). While all seedlings of C. sieboldii died within 2 years under 0.15 and 0.3% RLI, about half of the seedlings of C. cuspidata survived more than 2 years under 0.15% RLI, and about 70% survived more than 4 years under 0.3% RLI. It was concluded that C. cuspidata was more shade tolerant than C. sieboldii, and the possibility that C. sieboldii might be more tolerant of the drought stress than C. cuspidata was discussed.
Effects of arrival order and seed size on germination of grassland plants: Are there assembly rules during recruitment?
Authors: ERIKSSON OVE , ERIKSSON ÅSA
Published: March 2003

Assembly rules provide a tool to simplify the complexity of interactions that shape ecological communities. The prime objective of this study was to examine an experimental approach to the study of assembly rules, and also to examine some premises of such rules. We investigated possible assembly rules pertaining to interactions among seeds and seedlings during germination. An experiment was made on randomly sampled species pairs from a larger pool of grassland species differing in seed size, and included treatments altering the presence and ordering of species arrival (seed sowing), and nutrient level. The basic premises suggested for the rules were that a congruence exists among species in the response of germination: (i) to environmental variation; and (ii) to the presence of other species. Both of these premises were supported. In nine of 11 investigated species, germination responded to sowing treatments. Germination was commonly enhanced in species sown after another species. Inclusion of a third species did not alter two‐species interactions during germination, indicating that increasing complexity may not change fundamental rules of assembly. Seed size had no systematic effect on how species behaved in the germination treatments. We suggest that assembly rules during recruitment may be useful for understanding pattern and process in plant communities, and that a method with random sampling of two‐species interactions is useful to handle the complexity of multi‐species communities. However, studies under field conditions are necessary to make further advances in the formulation of realistic assembly rules.
Different distribution patterns of woody species on a slope in relation to vertical root distribution and dynamics of soil moisture profiles
Authors: Yanagisawa Nao , Fujita Noboru
Published: March 2003

Distribution patterns along a slope and vertical root distribution were compared among seven major woody species in a secondary forest of the warm‐temperate zone in central Japan in relation to differences in soil moisture profiles through a growing season among different positions along the slope. Pinus densiflora, Juniperus rigida, Ilex pedunculosa and Lyonia ovalifolia, growing mostly on the upper part of the slope with shallow soil depth had shallower roots. Quercus serrata and Quercus glauca, occurring mostly on the lower slope with deep soil showed deeper rooting. Styrax japonica, mainly restricted to the foot slope, had shallower roots in spite of growing on the deepest soil. These relations can be explained by the soil moisture profile under drought at each position on the slope. On the upper part of the slope and the foot slope, deep rooting brings little advantage in water uptake from the soil due to the total drying of the soil and no period of drying even in the shallow soil, respectively. However, deep rooting is useful on the lower slope where only the deep soil layer keeps moist. This was supported by better diameter growth of a deep‐rooting species on deeper soil sites than on shallower soil sites, although a shallow‐rooting species showed little difference between them.
Microsatellite analysis of pollen flow in Rhododendron metternichii var. hondoense
Authors: Kameyama Yoshiaki , Isagi Yuji , Naito Kazuaki , Nakagoshi Nobukazu
Published: March 2003

Microsatellite analysis was used to characterize the patterns of pollen flow in a 150 m × 70 m quadrat containing 18 flowering trees of Rhododendron metternichii Sieb. et Zucc. var. hondoense Nakai. Using six microsatellite genetic markers and exclusion analysis, we determined the paternal trees of 216 seedlings germinated from five fruits produced by four adults. Each fruit was pollinated by a small number of largely adjacent trees, but 20–30% of pollen came from outside the quadrat. Adult trees that produced many flowers had a high self‐pollination rate. A directional flow of pollen from late‐blooming trees to early ones was observed.
Habitat use and diet of two stream gobies of the genus Rhinogobius in south‐western Shikoku, Japan
Authors: Sone Shin , Inoue Mikio , Yanagisawa Yasunobu
Published: March 2003

The importance of interspecific competition to habitat use by two congeneric stream gobies, Rhinogobius sp. LD (large‐dark type) and CB (cross‐band type), was studied by: (i) examining differences in habitat use by each species along the course of the stream; and (ii) comparing microhabitat use and the diet of each species between in allopatry and in sympatry in tributaries of the Shimanto River, south‐western Shikoku, Japan. Rhinogobius sp. LD mainly used riffles through the course of the stream. Although CB also mainly used riffles in the lower reaches where CB was numerically dominant, the greater use of riffles by CB was not observed in upper reaches where LD was dominant. Microhabitat analysis revealed that both LD and CB preferred lower bottom velocity in faster current in both allopatry and sympatry. In sympatry, however, LD used coarser substrate and faster current than CB, and both LD and CB used narrower ranges of microhabitat conditions than in allopatry. Dietary analysis indicated that both allopatric and sympatric LD preferred baetids, which are apt to drift, suggesting they adopted ambush foraging. Allopatric CB preferred leptophlebiids and chironomids, which are also apt to drift, whereas sympatric CB did not prefer such invertebrates. Overall results of this study suggest that LD and CB compete for better feeding habitats, CB shift their habitat use and foraging mode under the influence of LD, and current velocity and substrate coarseness are key factors in their habitat segregation.
Bark stripping of hinoki cypress by sika deer in relation to snow cover and food availability on Mt Takahara, central Japan
Authors: Ueda Hironori , Takatsuki Seiki , Takahashi Yasunori
Published: March 2003

Bark stripping of hinoki cypress (Chamaecyparis obtusa (Sieb. et Zucc.) Endl.) by sika deer (Cervus nippon Temminck) was monitored for 4 years on approximately 300 trees at three sites on Mt Takahara, central Japan. We investigated the effects of snow cover and food availability on seasonal and yearly changes in bark stripping. Bark stripping occurred during snowy periods (January and February) when less food was available because of the snow cover. The most serious bark stripping was observed in 1996 when the snow was the deepest and food resources were the poorest among the 4 years of the study. In contrast, bark stripping did not occur in 1999 when the snow was thin and, consequently, more food was available. These results suggest that snow cover and food avail‐ability influence the occurrence and intensity of bark stripping both seasonally and annually.
Distribution of plants in relation to microsites on recent volcanic substrates on Mount Koma, Hokkaido, Japan
Authors: TITUS JONATHAN H. , TSUYUZAKI SHIRO
Published: March 2003

On Mount Koma's volcanically devastated summit six common plant species colonized 12 microsite types differentially. Flat sites covered 65%, rills and gullies 16% and biotic sites 13% of the study area. Most species preferred sites near rocks and avoided flat and biotic microsites. Polygonum and Salix preferred gully bottoms and edges. Polygonum and Salix seedlings avoided flat areas and Polygonum seedlings strongly colonized gullies. Carex oxyandra seedlings preferred Salix patches. The distributions of seedlings and adult plants were correlated. Biotic microsites supported the largest Carex individuals, rills supported the largest Agrostis individuals and the largest Salix individuals were in gully bottoms and flats.
Long‐term carbon budget of the above‐ground parts of a young hinoki cypress (Chamaecyparis obtusa) stand
Authors: ADU‐BREDU STEPHEN , HAGIHARA AKIO
Published: March 2003

The carbon budget of the above‐ground parts of a young hinoki (Chamaecyparis obtusa) stand was analyzed over a 4‐year period to evaluate trends in changes in carbon use efficiency and growth conversion (biosynthetic) efficiency with stand development. Litter production of the stand was estimated from the stem cross‐sectional area at the crown base. A biomass increment was estimated using the stem volume of individual trees in the stand, measured at monthly intervals. Net production, estimated from litter production and the biomass increment, was 7.40, 8.44, 8.45 and 8.29 Mg C ha−1 year−1 for Years I–IV, respectively. The respiration rate of the entire above‐ground parts of selected sample trees were measured at monthly intervals using the enclosed whole‐tree method. The Q10 value of respiration decreased with increasing air temperature. Respiration rate was partitioned into growth and maintenance components using a two‐component functional model. The maintenance respiration coefficient increased in the following order: winter, spring, autumn and summer. The maintenance respiration coefficient also decreased with either stand development or age for all seasons. The growth respiration coefficient, which did not vary with stand development, was 0.69 ± 0.08 (mean ± SE), 0.61 ± 0.03, 0.54 ± 0.03 and 0.67 ± 0.07 g C g−1 C for winter, spring, summer and autumn, respectively. The growth conversion efficiency of the stand was 0.76, 0.72, 0.72 and 0.75 for Years I–IV, respectively. Carbon use efficiency was estimated to be 0.58, 0.57, 0.54 and 0.53 for Years I–IV, respectively. The hypothesis that respiration reduces productivity in old stands could not be validated for this hinoki stand.
Travellers in many guises: The origins and destinations of dendritic cells
Authors: Cavanagh Lois L , Von Andrian Ulrich H
Published: March 2003

The migratory behaviour of dendritic cells (DC) is tightly linked to their differentiation state. Precursor DC constitutively repopulate normal tissues from the bloodstream, and are recruited in elevated numbers to sites of inflammation. Whilst maturing in response to antigenic stimulation, DC acquire the capability to enter lymph nodes via afferent lymphatic vessels, thus facilitating their presentation of antigen to naïve T cells. Peripheral blood monocytes constitute a second DC precursor population, which during an inflammatory response are recruited to the affected site where some differentiate into functional DC. The availability of separate DC precursor populations is thought to be significant for the character, amplification and perpetuation of the resultant immune response. In addition, the balance between steady‐state trafficking of incompletely activated DC bearing self‐antigens from the periphery, and the migration of fully mature DC from inflammatory sites into lymph nodes might have profound effects upon tolerance induction and activation of T cells, respectively.
Best practice: What it is and what it is not
Authors: Smith Colleen , Sutton Frances
Published: March 2003

This paper offers a poststructural critique of the concept of best practice and suggests that those practising best practice seek to reinforce modernist notions of health care and health‐care delivery. Modernist notions limit possibilities for health‐care workers, including nurses, as well as limiting the care delivered to clients. In turn, these mask various outcomes for clients and health‐care workers. This paper explores the concept of best practice and the discourse on which it is based and offers an alternative perspective on which high quality health‐care services can be developed.
An introduction to sensitivity, specificity, predictive values and likelihood ratios
Authors: Chu Kevin
Published: March 2003

Objective: To assist clinicians and other health‐care providers to understand the terms used to describe the accuracy of diagnostic tests.

Methodology: This paper reviews the calculation and interpretation of sensitivity, specificity, predictive values, receiver operating characteristic curves and likelihood ratios.

Results: Sensitivity and specificity are measures of the accuracy of a diagnostic test. There is a trade‐off between sensitivity and specificity that is dependent on the cut‐off level chosen for a positive diagnosis. Predictive values are measures of the usefulness of a test once the test results are known. Predictive values depend on the prevalence of the disease, as well as on the sensitivity and specificity of the test. Sensitivity, specificity and predictive values are easily calculated by the construction of a two‐by‐two table. Multiple testing, either in parallel or in series, can alter the sensitivity, specificity and predictive values. Receiver operating characteristic curves plot the relationship between sensitivity and specificity at various cut‐offs, facilitating the comparison of accuracy among tests. Likelihood ratios are an alternative measure of accuracy and have the advantage of being able to assess multiple test outcomes, rather than simply assessing dichotomized positive or negative results.

Conclusion: An understanding of how the measurements that are used to describe the accuracy of diagnostic tests are calculated is essential to the interpretation of test results.