Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Lateral Line System”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 613 records · Page 34Linked to original sources
PubMed1976

[Vascularization of the anal canal].

The arterial blood supply of the anal canal derives from the superior, middle and inferior rectal arteries, whose branches reach the anal submucosa. Three main arterial trunks in the right anterior, right posterior and left lateral positions can be isolated below the pectinate line. They come, for the most important part, from the superior rectal artery. On the course of the anal submucosal venous plexus are fusiform, saccular or serpiginous dilatations confined to the lower half of the anal canal. This plexus is mainly tributary of the superior rectal vein to the portal system and secondly, of the middle and inferior rectal veins and the lateral sacral veins to the inferior vena cava. Arterio-venous direct communications have been demonstrated by serial section and by radiography of cadaveric specimens and by selective inferior mesenteric arteriography in patients. The erectile property of the anal submucosa as suggested by large vascular spaces, arterio-venous shunts and glomic systems may function in the erectile mechanism.

Anal Canal↗
PubMed2003

Expression of the Hsp23 chaperone during Drosophila embryogenesis: association to distinct neural and glial lineages.

BACKGROUND: In addition to their strong induction following stress, small heat shock proteins (Hsp) are also expressed during development in a wide variety of organisms. However, the precise identity of cell(s) expressing these proteins and the functional contribution of small heat shock proteins in such developmental context remain to be determined. The present study provides a detailed description of the Drosophila small heat shock protein Hsp23 expression pattern during embryogenesis and evaluates its functional contribution to central nervous system development. RESULTS: Throughout embryogenesis, Hsp23 is expressed in a stage-specific manner by a restricted number of neuronal and glial lineages of the central nervous system. Hsp23 is also detected in the amnioserosa and within a single lateral chordotonal organ. Its expression within the MP2 lineage does not require the presence of a functional midline nor the activity of the Notch signaling pathway. Transactivation assays demonstrate that transcription factors implicated in the differentiation of the midline also regulate hsp23 promoter activity. Phenotypic analysis of a transgenic line exhibiting loss of Hsp23 expression in the central nervous system suggests that Hsp23 is not required for development and function of this tissue. Likewise, its overexpression does not cause deleterious effects, as development remains unaffected. CONCLUSIONS: Based on the presented data, we suggest that the tightly regulated developmental expression of Hsp23 is not actively involved in cell differentiation and central nervous system development per se but rather reflects a putative role in preventive "pre-stress" neuroprotection or in non-vital process(es) common to the identified cell lineages.

Animals↗
PubMed2002

Oxidative modulation of nuclear factor-kappaB in human cells expressing mutant fALS-typical superoxide dismutases.

Previous evidence supports the notion of a redox regulation of protein phosphatase calcineurin that might be relevant for neurodegenerative processes where an imbalance between generation and removal of reactive oxygen species occurs. We have recently observed that calcineurin activity is depressed in human neuroblastoma cells expressing Cu,Zn superoxide dismutase (SOD1) mutant G93A and in brain areas from G93A transgenic mice, and that mutant G93A-SOD1 oxidatively inactivates calcineurin in vitro. We have studied the possibility that, by interfering directly with calcineurin activity, mutant SOD1 can modulate pathways of signal transduction mediated by redox-sensitive transcription factors. In this paper, we report a calcineurin-dependent activation of nuclear factor-kappaB (NF-kappaB) induced by the expression of familial amyotrophic lateral sclerosis (fALS)-SOD1s in human neuroblastoma cell lines. Alteration of the phosphorylation state of IkappaBalpha (the inhibitor of NF-kappaB translocation into the nucleus) and induction of cyclooxygenase 2 are consistent with the up-regulation of this transcription factor in this system. All of these modifications might be relevant to signaling pathways involved in the pathogenesis of fALS.

Amino Acid Substitution↗
PubMed1983

The nucleus praeeminentialis: a Golgi study of a feedback center in the electrosensory system of gymnotid fish.

The cytoarchitecture of the dorsal nucleus praeeminentialis in two families of weakly electric fish (Eigenmannia viriscens and Apteronotus albifrons) was examined in both Nissl and Golgi material, and an attempt was made to correlate this information with our data from HRP studies on the afferent and efferent connections of this nucleus. The n. praeeminentialis is an isthmic structure located dorsolateral to the lateral lemniscus and anterior to the eminentia granularis--a subdivision of the archicerebellum of fish. The n. praeeminentialis can be divided into a large dorsal portion concerned with electroreception and a small ventral portion involved with the lateral line mechanoreception. The dorsal n. praeeminentialis consists of three parts: a pars medialis, a large pars principalis (p.P.) and a narrow pars lateralis. The p.P. presents three zones: a dorsal, a central, and a ventral zone, which are reciprocally and topographically connected with the zones of the electroreceptive lateral line lobe (ELLL), medial ELLL with ventral zone, central ELLL with central zone, and lateral ELLL with dorsal zone. Several types of projection cells are present in the n. praeeminentialis: (a) neurons that show preferential orientation of their long dendrites in relation to the afferent fiber systems, (b) cells with wide dendritic fields radiating in all directions, and (c) cells with small polarized dendritic fields toward the incoming ELLL afferents. Interneurons are also identified, showing different axonal ramification patterns. The afferent and efferent fiber systems linking the n. praeeminentialis to ELLL, lobus caudalis (L.C.), and torus semicircularis (T.S.d.) point to the important position of this nucleus in the feedback loop of the electrosensory pathway. The complex processing within this nucleus is reminiscent of the feedback loops in the auditory system.

Afferent Pathways↗
PubMed2004

Crucial role of synovial lining macrophages in the promotion of transforming growth factor beta-mediated osteophyte formation.

OBJECTIVE: To investigate in vivo and in vitro whether macrophages have an intermediate role in transforming growth factor beta (TGFbeta)-induced osteophyte formation. METHODS: In vivo, synovial lining macrophages were selectively depleted by injection of clodronate-laden liposomes 7 days prior to injection of 20 ng or 200 ng of TGFbeta into murine knee joints 3 times, on alternate days. Total knee joint sections were obtained on day 7 after the last injection and stained with Safranin O. Production of bone morphogenetic protein 2 (BMP-2) and BMP-4 was determined by immunolocalization. The interaction between murine macrophages and mesenchymal cells (precursors with chondrogenic potential) was studied in vitro using a Transwell system in which RAW macrophages were cocultured with C3H10T1/2 mesenchymal cells. Spheroid neocartilage formation was quantified microscopically after staining with May-Grünwald-Giemsa. RESULTS: Triple injections of 20 ng or 200 ng of TGFbeta into normal murine knee joints induced significant osteophyte formation at the lateral and medial sites of the patella and femur on day 7 after the last injection. Strikingly, removal of synovial lining macrophages prior to TGFbeta injection resulted in a drastic reduction of osteophyte formation (by 70% and 64% after injection of 20 ng and 200 ng of TGFbeta, respectively). Synovial lining cells produced BMP-2 and BMP-4 after TGFbeta stimulation, whereas BMP-2 and BMP-4 were absent in the synovial tissue after macrophage depletion. In vitro, clustering and spheroid formation of C3H10T1/2 was induced by TGFbeta concentrations of >1 ng/ml. However, in the Transwell system, in the presence of murine macrophages, 0.5 ng/ml of TGFbeta was very effective in generating large spheroids, suggestive of macrophage-derived (co)factors. In coculture supernatants, TGFbeta concentrations were not elevated in the presence of macrophages, indicating generation of other growth factors involved in spheroid formation. CONCLUSION: These findings indicate that macrophages are crucial intermediate factors in osteophyte formation induced by TGFbeta, probably by inducing other chondrogenic signals.

Animals↗
PubMed2006

Muscle-derived but not centrally derived transgene GDNF is neuroprotective in G93A-SOD1 mouse model of ALS.

Glial cell line-derived neurotrophic factor (GDNF) is a potent survival factor for motoneurons (MNs), and is considered a potential agent for the treatment of amyotrophic lateral sclerosis (ALS) and other MN diseases. The effectiveness of GDNF may depend significantly upon its route of delivery to MNs. In this study we tested the neuroprotective effects of target-derived and centrally derived GDNF in the G93A-SOD1 mouse model of ALS using a transgenic approach. We found that overexpression of GDNF in the skeletal muscle (Myo-GDNF mice) significantly delayed the onset of disease and increased the life span of G93A-SOD1 mice by 17 days. The duration of disease also increased by 8.5 days, indicating that GDNF slowed down the progression of disease. Locomotor performance in Myo-GDNF/G93A-SOD1 mice was also significantly improved. The behavioral improvement correlated well with anatomical and histological data. We demonstrated that muscle-derived GDNF resulted in increased survival of spinal MNs, and twice as many MNs survived in end-stage double transgenic mice compared to end-stage G93A-SOD1 mice. Muscle-derived GDNF also had profound effects on muscle innervation and axonal degeneration. Significantly higher numbers of completely or partially innervated NMJs and large caliber myelinated axons were found in double transgenic mice. In contrast, we demonstrated that overexpression of GDNF in astrocytes in the CNS (GFAP-GDNF mice) failed to demonstrate any neuroprotective effects in G93A-SOD1 mice both on behavioral and histological levels. These data indicate that retrograde transport and signaling of GDNF is more physiological and effective for ALS treatment than anterogradely transported GDNF.

Amyotrophic Lateral Sclerosis↗
PubMed1996

Changes in cellular distribution of connexins 32 and 26 during formation of gap junctions in primary cultures of rat hepatocytes.

In the adult rat hepatocyte, gap junction proteins consist of connexin 32 (Cx32) and connexin 26 (Cx26). Previously, we reported that both Cx32 and Cx26 were markedly induced and maintained in primary cultures of adult rat hepatocytes. The reappearing gap junctions were accompanied by increases in both the proteins and the mRNAs, and they were well maintained together with extensive gap junctional intercellular communication (GJIC) for more than 4 weeks. In the present study, we examined the cellular location of the gap junction proteins and the structures in the hepatocytes cultured in our system, using confocal laser microscopy and immunoelectron microscopy of cells processed for Cx32 and Cx26 immunocytochemistry and freeze-fracture analysis. In immunoelectron microscopy, the size of Cx32-immunoreactive gap junction structures on the plasma membrane increased with time of culture, and some of them were larger than those in liver sections in vivo. Freeze-fracture analysis also showed that the size of gap junction plaques increased and that the larger gap junction plaques were composed of densely packed particles. These results suggest that in this culture system, not only the synthesis of Cx proteins but also the size of the gap junction plaques was increased markedly. In the adluminal lateral membrane of the cells, Cx32-immunoreactive lines were observed and many small gap junction plaques were closely associated with a more developed tight junction network. In the basal region of the cells, small Cx32- and Cx26-immunoreactive dots were observed in the cytoplasm and several annular structures labeled with the antibody to Cx32 were observed in the cytoplasm. These results indicated the formation and degradation of gap junctions in the cultured hepatocytes.

Animals↗
PubMed1996

Polymer-encapsulated genetically modified cells continue to secrete human nerve growth factor for over one year in rat ventricles: behavioral and anatomical consequences.

The long-term delivery of growth factors and other proteins into the CNS at putatively therapeutic yet safe levels continues to be technically constrained. In the present studies, the gene encoding human nerve growth factor (hNGF), introduced into a dihydrofolate reductase-based pNUT expression vector system, was engineered into a clonal baby hamster kidney (BHK) cell line. BHK-hNGF23 and mock-transfected cells were encapsulated in an immunoisolating polymeric device and transplanted into the lateral ventricles of healthy young adult rats for 13.5 months. As measured by ELISA, nanogram quantities of hNGF were released by encapsulated cells both prior to implantation (3.6 +/- 0.8 ng/device/24 h) and upon removal from rat lateral ventricles after 13.5 months in vivo (2.2 +/- 0.4 ng/ device/24 h). In addition, the hNGF released into the tissue culture medium was biologically active. Long-term encapsulated cell survival was confirmed by histologic analysis. The presence of genomic DNAs (hNGF transgene), as determined by PCR analyses, revealed that the transgene copy number from the recovered BHK-hNGF23 cells after 13.5 months in vivo was equivalent to preimplant levels. No deleterious effects from hNGF were detectable on body weight, mortality rate, motor/ambulatory function, or cognitive function as assessed with the Morris water maze and delayed matching to position in healthy young adult rats. In addition, there was no evidence that hNGF from these encapsulated cells produced hyperalgesia. Only tests of somatosensory thresholds revealed statistically significant effects related to the hNGF delivered in the present study, and that effect was limited to a decrease in the number of trials to asymptote. Animals receiving BHK-hNGF23 implants exhibited a marked hypertrophy of cholinergic neurons within the striatum (22% increase) and nucleus basalis (7% increase) but not the medial septum ipsilateral to the capsule. Moreover a robust sprouting of cholinergic fibers was observed within the frontal cortex and lateral septum proximal to the implant. These results indicate that encapsulated xenogeneic cells provide a safe and effective method for the long-term delivery of hNGF and potentially other neurotrophic factors within the CNS.

Animals↗
PubMed2001

Gene stability in transgenic aspen (Populus). II. Molecular characterization of variable expression of transgene in wild and hybrid aspen.

In many annual plant species, transgene inactivation occurs most often when multiple incomplete/complete copies of the transgene are present in a genome. The expression of single-copy transgene loci may also be negatively influenced by the flanking plant DNA and/or chromosomal location (position effect). To understand transgene silencing in a long-lived tree system, we analyzed several wild (Populus tremula L.) and hybrid (P. tremula L. x P. tremuloides Michx.) aspen lines transgenic to the rolC phenotypical marker system and grown under in vitro, greenhouse and field conditions. The morphological features of the 35S-rolC gene construct were used to screen lines with altered transgene expression, which was later confirmed by Northern experiments. Molecular analyses of hybrid aspen revealed that transgene inactivation was always a consequence of transgene repeats. In wild non-hybrid aspen, however, multiple-insertion-based altered or loss of rolC expression was observed only in three out of six lines showing transgene inactivation. Sequencing analysis revealed AT-rich patches at the transgene flanking genomic regions of some of the wild aspen transgenic lines. One wild aspen line showing variable rolC expression revealed characteristic integration of the transgene into genomic regions containing a high AT content (85% or more). In the remaining two wild aspen transgenic lines unstable for rolC expression, single-copy integration and non-AT-rich or repeat-free transgene flanking regions were found. A partial suppression of rolC was observed in some plants of one of the field-grown wild aspen transgenic lines. In the other wild aspen transgenic line an additional mutant phenotype along with transgene inactivation was found. This indicates that the host genome has some control over expression of a transgene, and the possible role of AT-rich regions in defense against foreign DNA.

Chromosome Mapping↗
PubMed1994

Modified method for the performance of glucose insulin clamp studies in conscious rats.

A modified method for performance of insulin-glucose clamp studies in rats was developed via catheterization of the tail vessels, after preconditioning of animals to limited restraint. The procedure is performed in conscious animals under local anesthesia and employs a specially designed foam rubber jacket which allows the animal mobility of the limbs and forward vision. In addition, a table utilizing a belt system allows easy positioning of the animal in the left and right lateral and supine positions during surgery. After initial development of the procedure, its use in 123 animals is reported. Line placement was successfully achieved in all cases with insignificant blood loss or morbidity and zero mortality. We note that 11% of animals did not complete the subsequent insulin-glucose clamp study due to either one of the vascular cannulae leaving the vessel (one animal), venous rupture (12 animals), or cannula blockage unrelated to surgical technique (one animal). Studies on Wistar Kyoto, Spontaneously Hypertensive, and Sprague-Dawley rats showed a fall in catecholamines after animals were replaced in cages, with stabilization within 30 min. In comparison to traditional techniques, this method is, therefore, proposed as a less traumatic and rapid way of performing infusion studies in conscious rats with a high success rate and minimization of loss of animal life due to procedural problems.

Anesthesia↗
PubMed1999

Electro-chemically activated water in dental unit water lines.

OBJECTIVE: To investigate the effect of electro-chemically activated water on biofilm contamination in dental unit water lines. DESIGN: Thirteen dental units fitted with independent water systems and used for 12 years with distilled water were divided into two groups, A and B. At the start, one week later, and again four weeks later, the bacterial counts in water from all units were determined. Also specimens of tubing were taken from the units at the beginning and at the end of the study for SEM investigation. In Group A distilled water was replaced with electrochemically activated water (a Russian invention), and used continuously for the duration of the study. In group B, distilled water was used as before, until confirmed to be contaminated. For ethical reasons group B was treated, one week into the study with conventional disinfectants. SETTING: The project was carried out in a clinic of a department of periodontology of a faculty of dentistry during 1998. RESULTS: Both groups showed a marked reduction in bacterial counts. Under SEM Group A showed a total elimination of the biofilm and Group B a partial removal. CONCLUSIONS: Distilled water was ineffective in controlling bacterial counts and biofilm. Electrochemically activated water was effective for this purpose.

Biofilms↗
PubMed1994

The production of a monoclonal T3-antiidiotypic antibody (T3-MAAB) that mimics the effects of T3 on 2-deoxy-D-glucose uptake in chick embryo heart cells.

The Ig fraction of rabbit anti-T3 antibody was injected into the spleens of BALB/c mice. Four days later, the lymphocytes were recovered from their spleens and were fused with cells of the 653 myeloma cell line. Screening of the hybrid colonies was carried out in a T3 RIA system. Positive colonies were those whose supernatant displaced 125I-labeled T3 from its antibody. The positive cultures were recloned and one was injected ip into mice. The crude IgG fraction of the ascites fluid was affinity purified on an affigel-10 column containing a covalently bound rabbit anti-T3-IgG. In order to eliminate possible endogenous T3 contamination during the affinity purification, the column was stripped with a 40% solution of acetonitrile in 0.2 M acetic acid, neutralized, and then the purification proceeded as described. The affinity purified antibody was an IgG2a isotype. This monoclonal antibody (T3-MAAB) displaced labeled T3 from its antibody in an RIA system. It also mimicked T3 in the stimulation of [3H]2-deoxy-D-glucose (2-DOG) uptake in cultured chick embryo heart cells. After 6 h exposure, the dose-response curve of 2-DOG uptake to T3-MAAB was shifted to the left by at least one order of magnitude when compared to the dose-response curve obtained with T3. After 24 h exposure, T3 had the expected additional stimulatory effect that was dependent on neosynthesis of proteins, while T3-MAAB did not. Also at 24 h exposure, T3-MAAB did not stimulate the incorporation of labeled leucine and uridine into the heart cells while T3 at an equivalent concentration did. The MAAB activity could be abolished by boiling, while boiling did not affect the activity of an equivalent concentration of T3, thus excluding a T3 contamination-mediated effect. We conclude, therefore, that (a) a monoclonal hybridoma producing an antibody that mimics T3 was established; (b) this antibody competed with labeled T3 for anti-T3 antibody and, like T3, stimulated sugar uptake into cultured chick embryo heart cells; and (c) this antibody, unlike T3, did not stimulate the neosynthesis of proteins.

Animals↗
PubMed1989

The Emanuel Miller memorial lecture 1987. Childhood markers for adult disorders.

The paper is concerned with examining some indices, measured in childhood, that may be considered to be "vulnerability" or "genetic" markers for later adult disorder. The disorders of prime interest in this instance are schizophrenia and criminality. The source of data for the paper is a longitudinal study carried out in Mauritius, which started in 1972 with the examination of a total population of 3-yr-olds. While these subjects are not yet at an age when a sufficient number have developed schizophrenia to allow definitive statements to be made, sufficient data are available to indicate that indices employed as markers at age 3 predict later patterns of behaviour that are in line with studies in the literature as being characteristic of those who later become schizophrenic. The age 3 index which is employed is hyper- or hypo-activity of the electrodermal system. Later work has made particular use of smooth pursuit eye-movement, which has become a particularly strong candidate as a genetic marker for schizophrenia. Also reported is material that suggests that electrodermal activity may also be used to predict later delinquent patterns of behaviour.

Arousal↗
PubMed1975

Mauthner neuron field potential in newly hatched larvae of the zebra fish.

1. Extracellular unit recording was done in the brain and spinal cord of unanesthesized zebra fish larvae embedded in a drop of gelatin under a compound microscope. Startle responses were elicited either by vibrating a stylus against the ear vesicle, or by direct electrical stimulation of the spinal cord. 2. As in adult fish, the Mauthner neurons produced a prominent negative potential (0.5-1 mV) which occurred at the beginning of the startle reflex. The axonal conduction velocity was 1.7-3.7 m/s. 3. With vibratory stimulation, the startle reflex was elicited most reliably at rates of 1/min or less, though the Mauthner cells would follow stimulation rates of 1/s when the spinal cord was stimulated electrically. At this rate there was considerable fatigue of the spike itself, which became smaller in amplitude and longer in duration. 4. The auditory system functions during vibratory stimulation of the ear vesicle, and probably activates the Mauthner cells, though it was not concluded that this was an exclusive excitatory pathway during these experiments. Lateral line or purely tactile receptors might also be involved. The latency of the Mauthner spike varied inversely (range, 6-17.5 ms) with the intensity of the vibratory stimulus. Muscle contractions began 2 ms after the Mauthner spike. 5. We recorded several forms of startle behavior, including a single tail flip or a tail flip followed by regular or irregular tail movements. The Mauthner neuron almost always fired at the beginning of the response, but it never fired again during subsequent movements. This supports an earlier contention that the Mauthner cell initiates the tail flip but is not involved in iterative swimming behavior.

Acoustic Stimulation↗
PubMed1997

Vestibular compensation in lampreys: role of vision at different stages of recovery of equilibrium control.

The main motor disorder evoked by unilateral labyrinthectomy (UL) in the lamprey (Lampetra fluviatilis) is a complete loss of equilibrium and rolling (rotation about the longitudinal axis) during swimming. A previous study has shown that the recovery of equilibrium control in the lamprey takes, on average, 33 days. However, lampreys were able to maintain equilibrium if UL was combined with removal of the ipsilateral eye ('surgical compensation' of the vestibular deficit). It was suggested that tonic excitatory inflow, rather than specific information about the orientation of the animal in space delivered by the remaining eye, is important for the recovery of equilibrium control. In the present study, a number of experiments were designed to test this hypothesis. It was found that illumination of the eye contralateral to the UL or continuous electrical stimulation (10 Hz) of the corresponding optic nerve resulted in immediate restoration of equilibrium control. The same result was obtained when the vestibular nerve on the UL side was stimulated. Thus, the roll control system in the lamprey, driven by only one labyrinth, is able to maintain equilibrium provided that the lack of tonic inflow from the missing labyrinth is compensated for by tonic vestibular or visual input. The present study has also shown that the importance of visual input for maintaining equilibrium after UL decreases with time. In animals that achieved a high degree of compensation, removal of the eyes on day 23 after UL evoked decompensation, whereas removal on day 70 did not. A reduction of the significance of visual input was also observed in surgically compensated UL lampreys. In these animals, removal of the remaining eye on days 1-3 after the first surgery resulted in a complete loss of equilibrium, removal on day 7 resulted in a partial loss, whereas removal on days 48-55 did not affect the postural stability. Three lines of evidence suggest that asymmetrical visual input evokes plastic changes in the roll control system. (i) In one group of animals, initially one eye was removed, and then 50 days later the labyrinth ipsilateral to the missing eye and remaining eye were removed. These animals exhibited a mild impairment of equilibrium control, in contrast to the animals in which both surgeries were performed simultaneously. (ii) In another group of animals, initially one eye was removed, and then 50 days later the remaining eye and both labyrinths were removed. These animals exhibited rolling towards the eye that remained intact for longer. (iii) A short-term electrical stimulation (5-10 min daily for 3 days) of the optic nerve (contralateral to UL) in blinded animals considerably improved the equilibrium control compared with that of non-stimulated animals; the improvement was observed for 60 days after stimulation.

Animals↗
PubMed1985

Ultrastructure of the intrahepatic bile duct system of the one-humped camel (Camelus dromedarius).

The ultrastructure of the intrahepatic bile duct system of the camel was studied. Bile canaliculi are present as cavities containing numerous microvilli between adjacent hepatic cells. They are lined with cuboidal cells surrounded by a basal lamina. The lateral plasma membranes of adjacent cells form extensive evaginations below tight junctions at the lumenal surface. The basal surface is open. Collagen bundles are arranged mainly in parallel to the duct.

Animals↗
PubMed2004

Efficient activation of gene expression using a heat-shock inducible Gal4/Vp16-UAS system in medaka.

BACKGROUND: Genetic interference by DNA, mRNA or morpholino injection is a widely used approach to study gene function in developmental biology. However, the lack of temporal control over the activity of interfering molecules often hampers investigation of gene function required during later stages of embryogenesis. To elucidate the roles of genes during embryogenesis a precise temporal control of transgene expression levels in the developing organism is on demand. RESULTS: We have generated a transgenic Gal4/Vp16 activator line that is heat-shock inducible, thereby providing a tool to drive the expression of specific effector genes via Gal4/Vp16. Merging the Gal4/Vp16-UAS system with the I-SceI meganuclease and the Sleeping Beauty transposon system allows inducible gene expression in an entirely uniform manner without the need to generate transgenic effector lines. Combination of this system with fluorescent protein reporters furthermore facilitates the direct visualization of transgene expressing cells in live embryos. CONCLUSION: The combinatorial properties of this expression system provide a powerful tool for the analysis of gene function during embryonic and larval development in fish by ectopic expression of gene products.

Animals↗
PubMed1971

Influence of the duration of experimental fever on salicylate antipyresis in the rabbit.

1. Steady state fever has been produced in rabbits with a priming injection followed by a sustaining infusion of homologous plasma containing endogenous pyrogen (EP). This fever appears to last as long as the infusion continues.2. Intravenous salicylate given 1 h after the start of the EP infusion produced only a small antipyretic effect. The same dose of salicylate given 4 h after the start of an EP infusion resulted in rapid and progressive defervescence. Intermediate antipyretic responses were obtained when salicylate was administered intravenously 2 and 3 h after the start of an EP infusion.3. Less than 1% of the systemic dose, when injected into a lateral cerebral ventricle, produced a significantly smaller response at 1 h than at 4 h after the start of an EP infusion. At both these times the fall in temperature following the intraventricular salicylate injection was dose dependent, but the slope of the dose-response line was significantly steeper at 4 h than at 1 hour.4. It is suggested that salicylates produce their antipyretic effects by antagonizing the action of EP within the nervous system, and that the hypothalamic EP concentration falls during the course of an EP infusion.

Animals↗