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PubMed1985

Similar mechanism of various lupus anticoagulants.

Potent lupus inhibitors from various patients were mixed with platelet free normal plasma and were compared in activated partial thromboplastin time (APTT), dilute prothrombin time (dil. PT), kaolin clotting time (KCT), contact product clotting time (CPCT), and Russell viper venom clotting time (RVVCT) tests. In the last three tests platelets and platelet lipid substitutes were avoided to enhance the sensitivities of these tests for the lupus anticoagulant. Correlations between the KCT and the other tests were mostly good, indicating that different lupus inhibitors functioned by a similar mechanism. There was no significant trend between particular clinical symptoms and individual coagulation test combinations. The KCT was found to be the most sensitive test for the lupus inhibitor, followed by the CPCT, RVVCT, dil. PT and APTT tests. Activated platelets tended to correct the APTT lupus inhibitor defect in all except the strongest inhibitor cases.

Blood Coagulation Disorders↗

PubMed1994

N-type Ca2+ channels are located on somata, dendrites, and a subpopulation of dendritic spines on live hippocampal pyramidal neurons.

In the nervous system the influx of Ca2+ orchestrates multiple biochemical and electrical events essential for development and function. A major route for Ca2+ entry is through voltage-dependent calcium channels (VDCCs). It is becoming increasingly clear that the precise contribution VDCCs make to neuronal function depends not only upon their specific electrophysiological properties but also on their distribution over the nerve cell surface. One location where the presence of VDCCs may be critical is the dendritic spine, a structure known to be the major site of excitatory synaptic input. On spines, VDCCs are hypothesized to play an essential role in signal processing, learning, and memory. However, direct evidence for the presence of VDCCs on spines is lacking. Attempts to examine the distribution of VDCCs, or indeed any other components, on spines have been hampered since the size of many spines is close to the limits of resolution of conventional light microscopy. Using a new, biologically active, fluorescein conjugate of omega-conotoxin (Fl-omega-CgTx), a selective blocker of N-type VDCCs, and confocal microscopy, we have mapped the distributions of N-type VDCCs on live CA1 neurons in rat hippocampal slices. VDCCs were found on somata, throughout the dendritic arbor, and on dendritic spines in all hippocampal subfields. A comparison of three-dimensional reconstructions of structures labeled by Fl-omega-CgTx with those outlined by 1,1-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine (Dil) or Lucifer yellow confirmed the presence of N-type VDCCs on dendritic spines. However, spine frequency on dendrites labeled with Fl-omega-CgTx was much lower than the spine frequency on dendrites labeled with Lucifer yellow or Dil, suggesting that some spines lack N-type VDCCs. These results offer the first direct evidence for the localization of any voltage-dependent channel on dendritic spines. The presence of N-type VDCCs on dendrites and their spines argues that these channels may participate in the generation of active Ca2+ conductances in distal dendrites, and is consistent with a role for spines as specialized compartments for concentrating Ca2+.

Animals↗

PubMed1995

Modular organization of the pontine nuclei: dendritic fields of identified pontine projection neurons in the rat respect the borders of cortical afferent fields.

Cortical afferents transferring information destined for the cerebellum terminate in the pontine nuclei (PN) in a divergent and patchy fashion. We investigated whether the form of dendritic fields of pontine projection neurons which are postsynaptic to the cortical afferents are related to this patchy pattern. To this end we used a triple combination of (1) retrograde labeling (injection of Fluorogold into the brachium pontis), (2) anterograde labeling [injection of Dil into cortical areas A17 and Sml(forelimb)], and (3) subsequent intracellular fills of identified projection neurons (Lucifer yellow) in slightly fixed slices of pontine brainstem. In 64 projection neurons whose somata were located within 160 microns of the border defined by cortical afferent fields, most of the dendritic trees were found to respect the border. Strikingly, proximal dendrites which were oriented toward the border often bent in order to avoid the boundary. This observation was supported by a quantitative analysis. It revealed that overlap areas of dendritic fields with the neighboring compartment were significantly smaller than those of hypothetical, radially organized dendritic fields of the same size, indicating that the dendritic fields are indeed confined to single compartments. In a second series of experiments, double injections of the anterograde tracers Dil and DiAsp into adjacent sites within one cortical area (A17 or Sml) were made in order to test if the topology of the cortical map is preserved within individual pontine compartments. This, however, does not seem to be the case, since the terminal fields displayed a complex pattern of overlap and nonoverlap rather than a consistent shift of terminal fields expected in the case of preserved topology. The results of the present study are consistent with the view that pontine modules independently process information from different parts of individual cortical areas. We suggest that this characteristic property of the corticopontine projection system might be the morphological basis of the well established fact that somatotopically continuous sensory maps in the cortex are transformed into maps at the level of the cerebellar cortex, showing a fractured somatotopy.

Afferent Pathways↗

PubMed1995

The first retinal axons and their microenvironment in zebrafish: cryptic pioneers and the pretract.

The initial development of the optic tract was studied with light and electron microscopy in the zebrafish (Danio rerio). Intraocular injections of the fluorescent marker, 1,1'-dioctadecyl-3,3,3',3' tetramethylindocarbocyanine perchlorate (dil), labeled retinal axons and growth cones anterogradely, and injections of dil into the optic chiasm labeled retinal ganglion cells retrogradely. Labeled tissue was photoconverted and examined electron microscopically. The ventronasal retinal quadrant produced the first growth cones. They were the first growth cones in the optic stalk. The leading retinal growth cones, typically 4-10 in number, advanced alongside the tract of the postoptic commissure but rarely sent filopodia into it and never wrapped its axons. Instead, the retinal growth cones followed a pretract, a subpial region that was morphologically distinct from its surroundings and extended out in front of the leading growth cones, presaging the optic tract. Thus, the retinal growth cones, previously thought to be followers of preexisting axons, are actually cryptic pioneers whose proximity to the earlier axons masks their pioneering nature. We suggest that cryptic pioneers and pretracts are probably common elsewhere in the nervous system.

Aging↗

PubMed1995

Long aboral projections of Dogiel type II, AH neurons within the myenteric plexus of the guinea pig small intestine.

Enteric AH neurons, with multipolar Dogiel type II morphology, project around the circumference of the intestine to myenteric ganglia, the submucosa and mucosa. Using retrograde labeling in vitro, intracellular recording, dye filling and immunohistochemistry, the projections of these neurons along the intestine were studied. When the retrograde tracer, Dil, was applied to the myenteric plexus, labeled nerve cell bodies were located up to 111 mm orally but only 13 mm aborally, demonstrating a marked difference in the lengths of projections up and down the small intestine. Of labeled nerve cell bodies located 2-110 mm orally, 43% had Dogiel type II morphology and of these, 70% were immunoreactive for calbindin, a calcium binding protein exclusive to Dogiel type II neurons. Intracellular filling with neurobiotin revealed several long circumferentially directed nerve fibers and short, filamentous dendrites; thus these were "dendritic" Dogiel type II neurons. This class accounts for approximately 3-4% of all myenteric neurons, and about 10% of all Dogiel type II neurons. Intracellular recordings revealed AH cell characteristics, with long afterhyperpolarizations following their action potentials, pronounced slow excitatory synaptic inputs and a lack of fast excitatory synaptic inputs. Antidromic action potentials could be evoked from the Dil application site in some cells, confirming their aboral projection. This is the first account of a major aboral projection of AH/Dogiel type II neurons and suggests an important role in aborally directed reflexes in the intestine.

Action Potentials↗

PubMed1994

Reversal effects of several Ca(2+)-entry blockers, neuroleptics and local anaesthetics on P-glycoprotein-mediated vincristine resistance of L1210/VCR mouse leukaemic cell line.

The ability of several Ca(2+)-entry blockers, neuroleptics and local anaesthetics to depress the P-glycoprotein-mediated resistance to vincristine was studied in vitro using the L1210/VCR cell line. This cell line was obtained by long-term adaptation of the L1210 mouse leukaemic cell line on vincristine and showed an overexpression of P-glycoprotein and accompanying multidrug resistance (MDR) which was defined as a cell resistance to several cytostatics such as vincristine, vinblastine and actinomycin D. Efficiency of the drugs applied to reverse this resistance was as follows: for Ca(2+)-entry blockers: verapamil (VER) > or = galopamil (GAL) > flunarizine (FLU) >> diltiazem (DIL) > nimodipine (NIM) > or = nifedipine (NIM); for neuroleptics: trifluoperazine (TFP) > chlorpromazine (CHP) > thioridazine (TRD) > perphenazine (PER); for local anaesthetics: carbanilate-Ca7 > cinchocaine (CIN) >> carbanilate-Ca3 > articaine (ART) > carbanilate CAO > lidocaine (LID). Quaternary cabanilate derivatives (Ca7Q and Ca3Q) with permanent positive charge were found to be unable to reverse the vincristine resistance of L1210/VCR cells. No reasonable correlation between the ability of calcium-entry blockers (DIL, VER, GAL, NIF, NIM and FLU) to reduce the viability of L1210/VCR cells growing in the medium supplemented with vincristine and their reported affinity to the L-type of calcium channel was observed. On the other hand, significant positive correlations were observed between both the inhibitory action of local anaesthetics on propagation of action potential in rat sciatic nerve and the ability of drugs to interact with calmodulin and the ability of the respective drug to reverse the resistance of L1210 cells to vincristine.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed1994

Axons of early generated neurons in cingulate cortex pioneer the corpus callosum.

The internal capsule and corpus callosum are the two major efferent axonal pathways of the mammalian neocortex. Previous studies have shown that the first cortical axons to grow through the internal capsule, the pathway from cortex to its subcortical targets, are extended by subplate neurons, which are the earliest generated neurons in the neocortex. Here, we characterize the origin of the first axons to project through the other major efferent pathway of the cortex, the midline corpus callosum, which connects the two cortical hemispheres. Using anterograde Dil tracing, we show that cortical axons first cross the midline through the nascent corpus callosum at E17. Retrograde Dil labeling from medial cortex at E18 reveals that these axons originate from a discrete group of neurons in medial (presumptive cingulate) cortex. These early callosal cells have complex morphologies with highly branched dendrites and later appear to take on a pyramidal form characteristic of callosal neurons in deep layers of cingulate cortex. 3H-thymidine birthdating demonstrates that these cells are predominantly generated on E14, making them among the earliest generated neurons in this cortical region. Injections of retrograde tracers in one cortical hemisphere at late embryonic or early postnatal ages result in substantial numbers of neurons labeled in the ipsilateral subplate, but only a few neurons labeled in the contralateral subplate. Thus, subplate neurons do not pioneer or ever project in significant numbers through the corpus callosum. We conclude that the two major efferent pathways from cortex, the corpus callosum and the internal capsule, are pioneered by developmentally and spatially distinct populations of early generated cortical neurons.

Aging↗

PubMed1996

A flow cytometric competition technique for measuring interaction of LDL with cellular LDL-receptors applied to patients with mutant (Arg3500-->Gln) apolipoprotein B.

We report our experience with a method to evaluate binding and uptake in cells of low density lipoprotein (LDL) from heterozygous patients with familial defective apolipoprotein B-100 (FDB-LDL) and LDL from normolipidemic subjects (nonFDB-LDL). The method is based on competition for binding/uptake in Epstein-Barr Virus (EBV)-transformed lymphocytes or COS cells overexpressing an LDL-receptor transgene between fluorescently labeled LDL and the unlabeled LDL of interest, and measurements are by flow cytometry. With EBV-lymphoblasts, the ability of FDB-LDL to displace fluorescent LDL ("Dil"-LDL) from cells at 4 degrees C (binding) was reduced to approximately 1/3 of normal. Displacement of "Dil"-LDL by FDB-LDL from cells at 20 degrees C (binding/uptake) was reduced to less than 1/2 of normal. Similar results were obtained with COS cells. Freezing of serum to -80 degrees C for 24 hours did not affect results, and we could discriminate between binding/uptake of FDB-LDL and nonFDB-LDL prepared from serum that had been stored at -80 degrees C for three months.

Adult↗

PubMed1990

Polychlorinated biphenyls increase fatty acid desaturation in the proliferating endoplasmic reticulum of pigeon and rat livers.

1. Polychlorinated biphenyls (PCB) are abundant and persistent pollutants in the ecosystem. Commercial mixtures (e.g. Aroclor 1254) can contain up to 80 different isomers and congeners, many of which accumulate in biological systems by the ingestion of PCB-contaminated lipid components of food chains. 2. Commercial mixtures of PCB induce, in hepatic microsomal membranes in vivo, a variety of different forms of the cytochrome P-450 components of enzyme systems involved in the metabolism of drugs and other xenobiotics, and can also induce the proliferation of this membrane. Since these microsomal enzyme systems share a number of the requirements of microsomal fatty acid desaturases, we have investigated whether the induction by PCB in vivo of cytochrome-P-450-linked enzymes in the proliferating hepatic microsomal membrane of the pigeon and the rat is accompanied by increased proportions of polyunsaturated fatty acids in this membrane. 3. The most striking changes observed 120 h after treating pigeons and rats with 1.5 mmol Aroclor 1254/kg body mass were 2.2-fold and 1.6-fold increases, respectively, in the proportion of arachidonic acid in the hepatic microsomal membrane. When the effects of this treatment on the proliferation of this membrane and increase in liver mass are taken into account, the amount of arachidonic acid in the total microsomal membrane of pigeon and rat livers increased 6.7-fold and 1.9-fold, respectively. 4. These changes were accompanied by very significant increases in pigeons and rats of the concentration of hepatic microsomal cytochrome P-450, and in the activity in microsomal protein of a wide range of cytochrome P-450-dependent enzyme involved in the metabolism of drugs and other xenobiotics. 5. This effect of PCB, of increasing in vivo the degree of unsaturation of fatty acids of hepatic microsomal membrane, appears to be a novel finding, and does not seem to have been investigated for other drugs and xenobiotics. Preliminary results have shown that the effect is accompanied by substantial increases in the total activity of delta 6 and delta 5 microsomal fatty acid desaturases converting 18:2 (9, 12) (linoleic acid) to 20:4 (5, 8, 11, 14) (arachidonic acid) [Borlakoglu, J.T., Dils, R.R., Edwards-Webb, J.D. & Walker, C.H. (1988) Biochem. Soc. Trans. 16, 1072]. 6. It is postulated that there is a significant link between increased fatty acid desaturation and the induction of cytochrome-P-450-linked enzymes, and this is discussed in terms of the mechanisms involved in the metabolism of foreign compounds.

Animals↗

PubMed1997

Internalization of indium-labeled LDL through a lipid chelating anchor in human pancreatic-cancer cells as a potential radiopharmaceutical for tumor localization.

Low-density lipoproteins (LDL) labeled with indium via a lipid-chelating agent, the bis(stearylamide) of diethylenetri-aminepentaacetic acid (L), were evaluated as a potential radiopharmaceutical (111In-L-LDL) for tumor localization by studying their internalization in human pancreatic cancer cells (Capan-1). Using Dil-LDL (1,1'-dioctadecyl-3,3,3',3'-tetramethylindodicarbocyanine perchlorate-LDL), this cell line was shown to bind human LDL with a high-affinity saturable component and a low-affinity non-saturable (40%) component. The single saturable high-affinity binding site had a KD of 27.5 +/- 2.1 micrograms/ml and a maximal binding of 610 +/- 7.5 ng/ml protein. Electron-microscopic examination of the In-L-LDL particles revealed the peripheral distribution of the electron-dense indium atoms at the outer surface of LDL. The modified LDL were then shown to be internalized by the cells. After conjugation of In-L-LDL to colloidal gold to follow the different stages of internalization, electron-microscopic examination showed that the In-L-LDL gold conjugates were stuck to the external sheet of the plasma apical and microvilli membrane, into earlier and later endosomes and into multivesicular bodies, suggesting the penetration of the In-L-LDL particles into lysosomal vacuoles. The observation of In-L-LDL-gold conjugates in deep-seated cytoplasm suggests that LDL could be employed as a drug-transport vehicle for targeting cytotoxics or radionuclides close to the cell nucleus.

Carbocyanines↗

PubMed1997

Inaccurate projection of rat soleus motoneurons: a comparison of nerve repair techniques.

The objectives of this study were 1) to determine the degree to which soleus motoneurons find their appropriate target following crush and transection injuries to the sciatic nerve, and 2) to determine whether repair of a transected nerve with a silicone tube leads to greater specificity of reinnervation and recovery of muscle function than the standard epineurial suture repair method. Sixty adult female Sprague-Dawley rats were randomly assigned to one of three sciatic nerve injury groups: crush injury, transection with epineurial suture repair, or transection with a silicone tube repair. The degree to which soleus motoneurons were able to find their appropriate target following a sciatic nerve injury was examined using a double labeling dye technique in which the original soleus motor pool was labeled with fast blue and reinnervating motoneurons were labeled with Dil. Soleus motoneurons were able to find their appropriate target following a crush injury. The accuracy of reinnervation following a transection injury and repair, however, was relatively poor. Only 14% of the original soleus motoneurons found the correct target following a transection injury. Repair of a lesioned nerve with a silicone tube and a 5-mm gap as opposed to epineurial sutures did not increase the specificity of reinnervation or the degree of muscle recovery.

Animals↗

PubMed1995

Development of the hippocamposeptal projection in the rat.

We analyzed the development of the hippocamposeptal projection and the morphology of the neurons giving rise to this projection. The fluorescent tracer Dil was injected into the septal region or the hippocampus in fixed brains of embryonic and early postnatal rats. Anterogradely labeled hippocampal axons first reached the septal region at E16. They ran along the midline of the brain, thereby approaching the medial septum. Axons to the lateral septum were first observed around E18/19. The lateral septum is partly innervated by collaterals of axons that travel to the medial septum. The projection to the lateral septal nuclei becomes more massive during early postnatal stages, whereas that to the medial septum becomes smaller. Cells in the medial septum retrogradely labeled by injection into the hippocampus were first observed at E18. Thus, the hippocamposeptal projection is established earlier than the septohippocampal projection. The first hippocampal projection neurons are nonpyramidal neurons that appear to pioneer the pathway to the septum. Pyramidal cell axons follow this first cohort of axons into the medial septum. Pyramidal cells could be retrogradely labeled from the medial septum during the perinatal period but then diminished in number. At P10, only nonpyramidal cells were labeled by medial septal injections. This indicates that the pyramidal component of this projection is transient and is removed shortly after birth. However, as is known from other studies, hippocampal pyramidal cells give rise to a powerful projection to the lateral septum in adult animals. Our results show that there is a considerable remodeling of the projection from the hippocampus to the septum during ontogenetic development.

Animals↗

PubMed1995

Chick wing innervation. III. Formation of axon collaterals in developing peripheral nerves.

Axon navigation during vertebrate limb innervation has been shown to be associated with position-dependent changes in size and complexity of the axon growth cones, and sometimes with bifurcation of terminal growth cones and axon branching (Hollyday and Morgan-Carr, companion paper). We have further examined axon branching and asked whether it extends to the projection of collaterals to different nerves. Injections of horseradish peroxidase or Dil were made into individual peripheral nerves in the wings of chick embryos at stages 28-35, and the trajectories of solidly labeled axons were traced proximally from the injection site in tissue sections. During stages when the peripheral nerves were first forming in the shoulder region, collaterals of retrogradely labeled axons were frequently observed to project into uninjected nerves proximal to the injection site. These two-nerve collaterals were formed by a small percentage of axons in a high percentage of the embryos studied and could occur in both motor and sensory axons. Two-nerve collateral projections were observed between nerves separated along both the proximodistal and anteroposterior axes of the limb, but they were limited in spatial extent to nerves supplying adjacent limb regions and were never seen between nerves projecting to widely disparate regions of the limb. Collaterals were not seen at the plexus projecting to both dorsal and ventral pathways. The apparent frequency of two-nerve collaterals was found to decline progressively from stage 28-29 to stage 32; no two-nerve collaterals were seen in the proximal wing at stage 33 and older. The mechanism of their elimination is presently unknown.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed2003

Maturation of granule cell dendrites after mossy fiber arrival in hippocampal field CA3.

Most granule neurons in the rat dentate gyrus are born over the course of the first 2 postnatal weeks. The resulting heterogeneity has made it difficult to define the relationship between dendritic and axonal maturation and to delineate a time course for the morphological development of the oldest granule neurons. By depositing crystals of the fluorescent label Dil in hippocampal field CA3, we retrogradely labeled granule neurons in fixed tissue slices from rats aged 2-9 days. The results showed that all labeled granule cells, regardless of the age of the animal, exhibited apical dendrites. On day 2, every labeled neuron had rudimentary apical dendrites, and a few dendrites on each cell displayed immature features such as growth cones, varicosities, and filopodia. Some cells displayed basal dendrites. By day 4, the most mature granule neurons had longer and more numerous apical branches, as well as various immature features. Most had basal dendrites. On days 5 and 6, the immature features and the basal dendrites had begun to regress on the oldest cells, and varying numbers of spines were present. On day 7, the first few adult-like neurons were seen: immature features and basal dendrites had disappeared, all dendrites reached the top of the molecular layer, and the entire dendritic tree was covered with spines. These data show that dendritic outgrowth occurs before, or concurrent with, axon arrival in the CA3 target region, and that adult-like granule neurons are present by the end of the first week.

Aging↗

PubMed1990

Pharmacological modification of multi-drug resistance (MDR) in vitro detected by a novel fluorometric microculture cytotoxicity assay. Reversal of resistance and selective cytotoxic actions of cyclosporin A and verapamil on MDR leukemia T-cells.

A novel fluorometric microculture cytotoxicity assay (FMCA), based on measurements of fluorescein diacetate (FDA) hydrolysis and DNA staining by Hoechst 33342, was used for drug sensitivity testing and detection of resistance reversal in acute lymphoblastic leukemia (ALL) cell lines. The 72-hr assay was found to be sensitive, reproducible and linearly related to the number of viable cells within a broad range of cell concentrations. At clinically achievable drug concentrations, the calcium channel blocker Verapamil (ver) and the immunosuppressant Cyclosporin A (csA) were found to partly reverse acquired Vincristine (vcr) resistance in multi-drug resistant (MDR) T-ALL L100 cells with little or no effect on the drug-sensitive parental L0 cell line. By combining the fluorometric indices, we found that low concentrations of csA were growth-inhibitory, whereas higher concentrations (greater than 10 micrograms/ml) were progressively cytotoxic for drug-sensitive L0 cells. In MDR L100 cells, on the other hand, csA produced significant cell kill even at low drug concentrations. Ver had no effects on sensitive L0 cells but showed considerable cytotoxic action towards MDR L100 cells. There was no apparent relationship between drug reversal of vcr resistance and the cytotoxic actions of the drug per se since the calcium channel blocker diltiazem (dil) significantly potentiated the actions of vcr on MDR L100 cells without being more toxic to these cells (compared to vcr-sensitive L0 cells).

Benzimidazoles↗

PubMed1988

Prostacyclin and prostaglandin E2 secretions by bovine pulmonary microvessel endothelial cells are altered by changes in culture conditions.

The isolation and culture of pulmonary microvascular endothelial (MVE) cells from bovine lungs were established. Primary and early passaged cultures grew best in Dulbecco's Modified Eagle's Medium (DMEM) supplemented with 10% equine plasma-derived serum, bovine retinal growth extract (1%), and heparin (90 micrograms/ml) on gelatin coated plates. A second tissue culture procedure was prepared in which the isolation technique was the same except the culture medium consisted of DMEM supplemented with 10% plasma-derived serum. Either growth medium produced homogeneous, long term, serial cultures for up to 16 passages. MVE cells were characterized in part based on their morphology by light and electron microscopy and positive reaction to Factor VIII-related antigen and uptake of 1,1'-dioctacecyl-1,3,3,3'3-tetramethyl-indocarbocyanine perchlorate acetylated low density lipoprotein (Dil-Ac-LDL). MVE cells were also positive for angiotensin-converting enzyme (ACE) activity and the presence of ACE was localized on the cells by indirect immunofluorescence. MVE cells maintained in the presence of heparin and growth factor principally synthesized prostaglandin (PG) E2 (1512 +/- 159 pg/mg protein at 15 min) and smaller amounts of prostacyclin (PGI2) and thromboxane (Tx) A2 (316 +/- 43 and 588 +/- 105 pg/mg protein/15 min respectively) as measured by radioimmunoassay. However, prostanoid release was not elevated from basal levels upon incubation with arachidonic acid, bradykinin, or ionophore A23187. In contrast, MVE cells cultured without heparin and growth factor secreted more PGI2 than PGE2 (862 +/- 84 and 89 +/- 12 respectively). Incubation with arachidonic acid, bradykinin, or ionophore A23187 induced significant increases in PGI2 and PGE2 production (P less than 0.01). Pulmonary artery endothelial (PAE) cell cultures used as a control for comparison predominantly synthesized PGI2. These findings suggest that in vitro the vessel source and culture conditions may qualitatively and quantitatively affect the pattern and levels of prostanoid synthesized and secreted.

Animals↗

PubMed1990

In situ perfusion system for oral mucosal absorption in dogs.

To evaluate oral mucosal absorption of drugs in dogs, a newly designed in situ perfusion system with a circulating perfusion chamber was developed. The utility of the perfusion system was investigated by using three drugs: salicylic acid (SA), sulfadimethoxine (SM), and diltiazem (DIL). The oral mucosal absorption of the drugs could be adequately described by first-order rate processes. The absorption rate was independent of the amount of un-ionized drug, which varied with the pH of the solution. The absorption of SA was similar for various oral mucosal sites and for repeated experiments using the same site. Pharmacokinetic analysis for the plasma or medium concentration of SA after perfusion showed that SA was absorbed at the rate constant of 0.071 h-1, and that approximately 70% of SA absorbed from oral mucosa was transferred to the circulating blood.

Absorption↗

PubMed1991

Mapping the early development of projections from the entorhinal cortex in the embryonic mouse using prenatal surgery techniques.

The purpose of this work was to study the development of specific projections from the postero-lateral cortex during the third trimester of gestation in the mouse. To do this, we labeled undifferentiated lateral cortex with the fluorescent carbocyanine dye, Dil, in the embryonic day (E) 16 mouse embryo using exo utero surgical techniques (Muneoka, Wanek, and Bryant, 1986). Embryos were allowed to develop to term (postnatal day 0, P0) at which time the fiber patterns emanating from the marked regions were studied. Dye placement in the undifferentiated postero-ventral cortex produced labeled fibers in the hippocampal formation. A robust projection of the angular bundle into the CA1 region of the hippocampus was heavily labeled. In addition, in some animals, cortical tracts, such as the anterior commissure, corpus callosum, and a corticotectal tract, were labeled. These tracts have been described previously as scaffolding pathways in the fetal cat (McConnell, Ghosh, and Shatz, 1989), and other vertebrates (Wilson, Ross, Parrett, and Easter, 1990). Dye placement in adjacent, more anterior or dorsal areas showed strong labeling in cortical structures but no labeling in the hippocampal formation. These data indicate that, by birth, the temporal cortex is subdivided along the rostro-caudal axis as entorhinal cortex and perirhinal cortex, and along the dorso-ventral axis, as entorhinal cortex and neocortex. Also, these earliest connections are similar to adult connections in their specificity of target area selection. Therefore, these early, yet specific, connections may play a role int he formation of future connections during postnatal development.

Animals↗