Alteration in the release of endothelium-derived relaxing factors by alpha-adrenoceptor stimulation in the aorta of stroke-prone spontaneously hypertensive rats

1. Endothelium-dependent relaxation by alpha-adrenoceptor agonists was examined in the thoracic aorta from normotensive Wistar-Kyoto (WKY) rats and stroke-prone spontaneously hypertensive rats (SHRSP). 2. In ring preparations from both strains, noradrenaline-induced contraction was increased by L-nitro arginine (L-NNA), a NO synthesis inhibitor. 3. L-NNA increased the contraction induced by phenylephrine, an alpha1-adrenoceptor agonist. UK-14304 and clonidine, alpha2-adrenoceptor agonists, did not contract the preparations with intact endothelium. However, these agents contracted preparations when NO synthesis was inhibited. 4. In a precontracted preparation, clonidine and UK-14304 induced relaxations. The relaxations in SHRSP aorta were smaller than those in WKY aorta. 5. These results indicate that alpha-agonists release NO from endothelium in WKY and SHRSP aorta. The mechanism related to NO release by alpha2-adrenoceptor agonist is impaired in SHRSP aorta.

Effects of chronic treatment with carvedilol on abnormalities of endothelium-dependent relaxation and structure of endothelium in resistance arteries of SHRSP

1. This study investigated the effects of chronic treatment with carvedilol, a beta-blocking agent with an alpha-blocking activity, on blood pressure, endothelium-dependent relaxation and the endothelial structure of the mesenteric resistance artery in stroke-prone spontaneously hypertensive rats (SHRSP). 2. Chronic treatment with carvedilol at a dose range of 30-120 mg/kg per day lowered systolic blood pressure of SHRSP from 234.9 +/- 3.3 to 198.7 +/- 3.1 mmHg at 16 weeks of age. 3. Acetylcholine-induced endothelium-dependent relaxation was impaired in the mesenteric artery from SHRSP and high concentrations of acetylcholine produced contractions. The impairment of the relaxation was abolished in the presence of indomethacin. Carvedilol treatment improved the impairment in the preparation from SHRSP. The structural abnormality of endothelium was observed in the preparation from SHRSP. The abnormality could be prevented by the antihypertensive treatment. 4. These results suggest that the impairment of endothelium-dependent relaxation in the preparation from SHRSP is due to the corelease of an endothelium-derived contracting factor which is considered to be a product of cyclo-oxygenase pathway of arachidonic acid cascade and that the impairment can be prevented by the antihypertensive treatment with carvedilol.

Longitudinal organization of the anterior neural plate and neural tube

Over the last century, several morphological models of forebrain organization have been proposed that hypothesize alternative topological solutions for the relationships of the histogenic primordia. Central to all of these models are their definitions of the longitudinal axis and the longitudinal organization of the neural plate and neural tube. To understand the longitudinal organization of the anterior brain, we have sought to identify molecular properties that are continuous along the entire longitudinal axis of the embryonic CNS. In this essay, we describe studies of the expression of several genes in the mouse between 7.5 (presomite stage) and 10.5 days post coitum (dpc) that provide evidence for the trajectory of the anterior-posterior axis and the longitudinal organization of the anterior CNS. Specifically, we report that the expression of noggin, sonic hedgehog and Nkx-2.2 define longitudinal columns of cells that are present along the entire CNS axis. Within the forebrain, the expression of these genes, as well as that of Nkx-2.1 and BF-1, are in distinct longitudinal regions in the neural plate and tube. We demonstrate that the earliest longitudinal axon pathways of the forebrain are spatially correlated with the longitudinal domain defined by Nkx-2.2. Finally, expression of the former genes, and Otx-1 and Emx-2, suggests that the cephalic neural plate is organized into molecularly distinct domains delimited by longitudinal and transverse borders; these results provide a foundation for defining the mechanisms that pattern the neural plate.

Changes in lipid peroxide and antioxidant enzyme activities in corpora lutea during pseudopregnancy in rats

This study investigated the involvement of lipid peroxidation and antioxidant enzymes in the regulation of luteal function in pseudopregnant rats. The activities of superoxide dismutase (SOD), a specific scavenger of superoxide radicals, and glutathione peroxidase, a scavenger of hydrogen peroxide, and lipid peroxide concentrations were measured in the corpus luteum on days 1, 3, 5, 7, 9, 11 and 13 of pseudopregnancy. The activity of SOD in the corpus luteum gradually increased until day 9 of pseudopregnancy and decreased thereafter, in a similar manner to serum progesterone concentration. Glutathione peroxidase activity significantly increased from day 1 to day 3 and remained high until day 11 of pseudopregnancy. The concentrations of lipid peroxides in the corpus luteum increased from day 3 to day 13 of pseudopregnancy. The involvement of prostaglandin F2 alpha (PGF2 alpha) in the production of lipid peroxides in regression of the corpus luteum was investigated by administering PGF2 alpha (3 mg kg-1, s.c.) or saline on days 7, 9 and 12 of pseudopregnancy. Each group of rats was autopsied 2 h later, and SOD activity, glutathione peroxidase activity and the concentration of lipid peroxides in the corpus luteum were determined. PGF2 alpha significantly increased lipid peroxide concentrations in the corpus luteum on days 7, 9 and 12 of pseudopregnancy (approximately twofold increases on days 7 and 9, and a fivefold increase on day 12, compared with the control that received saline). The activity of SOD in the corpus luteum was significantly increased by PGF2 alpha on days 7 and 9, but not on day 12, of pseudopregnancy. PGF2 alpha did not cause any significant changes in glutathione peroxidase activity in the corpus luteum on days 7, 9 and 12 of pseudopregnancy. It is concluded that lipid peroxides play an important role in regulating luteal function in pseudopregnant rats.

Null mutation of Dlx-2 results in abnormal morphogenesis of proximal first and second branchial arch derivatives and abnormal differentiation in the forebrain

Genetic analysis of the development and evolution of the vertebrate head is at a primitive stage. Many homeo box genes, including the Distal-less family, are potential regulators of head development. To determine the function of Dlx-2, we generated a null mutation in mice using gene targeting. In homozygous mutants, differentiation within the forebrain is abnormal and the fate of a subset of cranial neural crest cells is respecified. The latter causes abnormal morphogenesis of the skeletal elements derived from the proximal parts of the first and second branchial arches. We hypothesize that the affected skull bones from the first arch have undergone a transformation into structures similar to those found in reptiles. These results show that Dlx-2 controls development of the branchial arches and the forebrain and suggests its role in craniofacial evolution.

Integrated electro-optic Q switching in a domain-inverted Nd:LiTaO(3) laser

We report a novel integrated Q-switched laser constructed from a bulk domain-inverted single Nd:LiTaO(3) crystal that combines the laser gain and the electro-optic effect. The Q of the cavity is controlled electro-optically by exploitation of the deflection that occurs at the boundary of two oppositely directed domains under the application of an electric field. The integrated Q-switching element, with dimensions of 4.1 mm x 4.6 mm x 1 mm, generates 22-ns pulses at 1.08 microm with a peak power of 64 W and an operating voltage of ~600 V. The output is seen to be completely free from prelasing or afterpulsing.

Pulmonary fibrosis and sea-blue histiocyte infiltration in a patient with primary myelofibrosis

The authors present the case of a 73 year old man with primary myelofibrosis, pulmonary fibrosis, and acquired sea-blue histiocytosis, who died of respiratory failure. Pathology of the lungs revealed infiltration by sea-blue histiocytes, and fibrosis in the alveolar septa, and clumps of these cells filling the alveolar spaces. Megakaryocytes were also occasionally observed in the alveolar capillaries.

Pulmonary fibrosis and sea-blue histiocyte infiltration in a patient with primary myelofibrosis

The authors present the case of a 73 year old man with primary myelofibrosis, pulmonary fibrosis, and acquired sea-blue histiocytosis, who died of respiratory failure. Pathology of the lungs revealed infiltration by sea-blue histiocytes, and fibrosis in the alveolar septa, and clumps of these cells filling the alveolar spaces. Megakaryocytes were also occasionally observed in the alveolar capillaries.

Effects of fibroblasts of different origin on long term maintenance of xenotransplanted human epidermal keratinocytes in immunodeficient mice

We examined effects of fibroblasts of different origin on long-term maintenance of xenotransplanted human epidermal keratinocytes. A suspension of cultured epidermal cells, originating from adult human trunk skin, was injected into double mutant immunodeficient (BALB/c nu/scid) mice subcutaneously, with or without cultured fibroblastic cells of different origin. At one week after transplantation, the epidermal cells generated epidermoid cysts consisting of human epidermis-like tissue. When the epidermal cells were injected alone or together with fibroblastic cells derived from human bone marrow, muscle fascia, or murine dermis, organized epidermoid cysts regressed within 6 weeks. In contrast, when the epidermal cells were injected together with human dermal fibroblasts, generated epidermoid cysts were maintained in vivo for more than 24 weeks. Histological examination showed that the reorganized epidermis, after injection of both epidermal keratinocytes and dermal fibroblasts, retained normal structures of the original epidermis during 6 to 24 weeks after transplantation. The results indicate that human dermal fibroblasts facilitate the long-term maintenance of the reorganized epidermis after xenotransplantation of cultured human epidermal keratinocytes by supporting self renewal of the human epidermal tissue in vivo.

T-brain-1: a homolog of Brachyury whose expression defines molecularly distinct domains within the cerebral cortex

The mechanisms that regulate regional specification and evolution of the cerebral cortex are obscure. To this end, we have identified and characterized a novel murine and human gene encoding a putative transcription factor related to the Brachyury (T) gene that is expressed only in postmitotic cells. T-brain-1 (Tbr-1) mRNA is largely restricted to the cerebral cortex, where during embryogenesis it distinguishes domains that we propose may give rise to paleocortex, limbic cortex, and neocortex. Tbr-1 and Id-2 expression in the neocortex have discontinuities that define molecularly distinct neocortical areas. Tbr-1 expression is analyzed in the context of the prosomeric model. Topological maps are proposed for the organization of the dorsal telencephalon.

Cadherin-11 expressed in association with mesenchymal morphogenesis in the head, somite, and limb bud of early mouse embryos

Cadherin-11 (cad-11) is a novel member of the cadherin family of cell adhesion molecules, having recently been identified by means of the polymerase chain reaction. To study the function and expression of this molecule, we cloned mouse, cad-11 cDNA. Transfection of L cells with cDNA led them to acquire a typical cadherin-dependent cell-cell adhesiveness, and the L cells expressing cad-11 did not coaggregate with L cells expressing E-, P-, N-, or R-cadherin when they were mixed, indicating that this novel cadherin has a homophilic binding specificity, as found for other cadherins. To determine the developmental expression pattern of this molecule, we performed in situ hybridization analysis on early mouse embryos. Cad-11 first appeared in mesodermal layers only in the head and tail regions at the mid-to-late primitive streak stages. In the head, this appearance was followed by strong expression in mesenchymal tissues including branchial arches. In the trunk, the paraxial mesoderm initially did not express cad-11. However, as the somites formed, they expressed cad-11, and this expression was strictly correlated with their initial condensation and segregation from the presomitic mesoderm. The cad-11 expression in the somites was eventually restricted to sclerotome cells. As the limb buds developed, cad-11 appeared in the distal portion of the limb mesenchyme, and, at later stages, its expression was most evident at the peripheral mesenchyme. Cad-11 was thus expressed by restricted populations of mesenchymal cells in early embryos, although it was also expressed in parts of the neural tube, such as the optic vesicle and dorsal midline, and in part of the otic vesicle. As a step to investigate the role of cad-11 in mesenchymal cell adhesion, we dissociated the limb bud mesenchyme into single cells, pelleted them, and cultured them as aggregates. In these cultures, cad-11-positive cells clearly sorted out of the negative cell population, suggesting that cad-11 might be involved in selective association of mesenchymal cells. For comparison, we studied the expression of N-cadherin and found that the expressions of these two cadherins were differential, and complementary in some tissues. These results suggest that cad-11 is involved in specific associations of subsets of mesenchymal cells and also of some neural cells during early embryogenesis.

Prolonged survival of mice with human gastric cancer treated with an anti-c-ErbB-2 monoclonal antibody

A monoclonal antibody (MAb), 4D5, specifically recognising an extracellular epitope of the c-ErbB-2 protein, inhibited the growth of human gastric cancer overexpressing c-ErbB-2 severe combined immunodeficient (SCID) mice. This antibody also reduced the mass of established tumours xenografted into SCID mice, whereas gastric cancer not expressing c-ErbB-2 exhibited no regression in response to 4D5 treatment. In addition, administration of 4D5 prevented colonisation of cancer cells and prolonged the survival of host SCID mice inoculated i.v. with c-ErbB-2-overexpressing tumour cells. This is the first reported study to show that treatment with a single antibody specific to c-ErbB-2 prolongs the survival of host SCID mice bearing xenotransplanted tumours.

Effects of NG-nitro-L-arginine on alpha-agonists-induced contraction of aortae from Wistar Kyoto rats and stroke-prone spontaneously hypertensive rats

Differences in the influences of endothelium-derived nitric oxside (NO) on alpha-agonists-induced contraction in the aortae of spontaneously hypertensive and normotensive rats were studied by blocking NO synthesis with NG-nitro-L-arginine (L-NNA). L-NNA potentiated the contraction induced by noradrenaline. The potentiation was smaller in the preparation from stroke-prone spontaneously hypertensive rats (SHRSP) than in the preparation from Wistar Kyoto rats (WKY). Similar potentiation was observed in the contraction induced by phenylephrine; the potentiation was also smaller in the preparation from SHRSP. alpha 2-agonists, clonidine and UK-14304 induced dose-dependent contraction only in the presence of L-NNA. The dose-response curves for alpha 2-agonists in SHRSP aorta were different from those in WKY aorta; the maximum tension was observed at the concentration of 10(-6) M in the preparation from WKY, while the contraction further increased up to 10(-4) M in the preparation from WKY. Noradrenaline, clonidine and UK-14304 but not phenylephrine induced relaxation which was blocked by L-NNA. The relaxation was impaired in the preparation from SHRSP in greater extent than that by acetylcholine. It is suggested that basic or noradrenaline-stimulated NO release from endothelium decreased in the preparation from SHRSP and that alpha 2-adrenoceptor of both the endothelium and smooth muscle may be altered in the preparation from SHRSP.

Immortalisation of human oesophageal epithelial cells by a recombinant SV40 adenovirus vector

We introduced the origin-defective SV40 early gene into cultured human oesophageal epithelial cells by infection of a recombinant SV40 adenovirus vector. The virus-infected cells formed colonies 3-4 weeks after infection in medium containing fetal calf serum. When the cells derived from 'serum-resistant' colonies were then maintained in the serum-free medium with a low calcium ion concentration, some of them passed the cell crisis and kept growing for over 12 months. These cells, regarded as immortalised cells, resembled the primarily cultured oesophageal epithelial cells in morphology and had some of their original characteristics. Treatment of the cells with a high calcium concentration induced phenotypic changes. These cells still responded to transforming growth factor beta. When the immortalised cells were injected into severe combined immunodeficient mice, they transiently formed epithelial cysts, although the typical differentiation pattern of the oesophageal epithelium was not observed. These cysts regressed within 2 months without development into tumours. The results indicated that human oesophageal epithelial cells were reproducibly immortalised by infection with a recombinant SV40 adenovirus vector at relatively high efficiency. The immortalised cells should be useful in studies on oesophageal carcinogenesis and in assessing the cooperative effects with other oncogene products or carcinogens.

Protein kinase C stimulates Ca2+ current in pregnant rat myometrial cells

The factors that regulate the voltage-dependent Ca2+ channels in pregnant uterine smooth muscle cells have not been elucidated, including any roles for protein kinase C (PKC). Therefore, the role of PKC in the regulation of the slow (L type) Ca2+ channels was examined in myometrial cells isolated from late pregnant (18-19 day) rat uterus, using the nystatin-perforated whole-cell voltage clamp. A PKC activator, phorbol 12,13-dibutyrate (PDB), increased the L-type Ca2+ current (ICa(L)). Bath application of PDB (0.03 and 0.3 microM) increased the peak amplitude of ICa(L) by 21 +/- 14% (n = 6) and 37 +/- 8% (n = 9, p < 0.01), respectively. PDB did not change the holding current or shift the current-voltage relationship for ICa(L). The PKC inhibitors, H-7 (20 microM) or staurosporine (10 nM), reversed the effect of PDB. These results indicate that PKC may play a role in regulating Ca2+ channel function in pregnant rat myometrial cells and, therefore, may be involved in control of uterine contraction.

Fine structure of the vomeronasal organ in the chinchilla (Chinchilla laniger)

Fine structure of the vomeronasal organ (VNO) was examined in the chinchilla (Chinchilla laniger) from a viewpoint of comparative anatomy. The VNO of chinchilla was a pair of tubular structure, about 6mm in length, and situated bilaterally along the base of the nasal septum. The VNO was encircled rostrally by the vomeronasal cartilage, but caudally by a bony capsule. The VNO communicated with the nasal cavity via a small pore at its rostral end, while it ended blindly at its caudal end. Its lumen was crescent to elliptical in a transverse plane, and lined medially with the vomeronasal sensory epithelium (VSE), but laterally with the vomeronasal respiratory epithelium (VRE). Jacobson's glands were tubulo-alveolar in type and distributed from the dorsolateral to the ventrolateral region of the VNO and opened with the duct to the lumen in the transitional region from the VSE to the VRE. Their secretions were periodic acid-Schiff (PAS)-positive but alcian blue (AB)-negative. The VSE consisted of sensory, supporting and basal cells. Supporting cells were characteristic of a large number of huge dense bodies in the perinuclear cytoplasm. The other ultrastructural features in sensory, supporting and basal cells of the VSE were similar to those in the previous reports. The VRE consisted of ciliated, non-ciliated and basal cells. Acinar cells of Jacobson's gland possessed two types of secretory granules. Secretory granules of one type were homogeneous and electronlucent, about 1,700nm in diameter, while granules of the other type were about 2,200nm in diameter, and various in electron density. The present findings suggest that the VNO is functionally active in the chinchilla.

Pulmonary fibrosis with megakaryocytoid cell infiltration and chronic myelogenous leukemia

The relationship between fibrosis and megakaryocytic infiltration in the lungs of patients with Philadelphia-chromosome (Ph1)-positive chronic myelogenous leukemia (CML) is the focus of this review. Ph1-positive megakaryocytes are thought to reach and accumulate in the pulmonary vasculature through the marrow-blood barrier. In 21 autopsied patients with accelerated phase or blastic crisis of CML, megakaryocytic infiltration to the lungs was demonstrated in 10 patients, myelofibrosis in 12 patients and both in 5 patients. In 2 of the 10 patients with increased megakaryocytes in the lungs, relatively new fibrosis and alveolar damage in the acute phase were demonstrated with the simultaneous occurrence of myelofibrosis-"myelopulmonary fibrosis."Leakage of mitogenic factors resulting from an abnormality in the packaging mechanism of alpha-granules in these cells termed acquired grey platelet syndrome could cause fibrosis in the lungs as well as the bone marrow.

Comparison of endothelium-dependent and -independent tension oscillation in aortae of stroke-prone spontaneously hypertensive rats and Wistar Kyoto rats

Differences in noradrenaline-induced tension oscillations between aortae from stroke-prone spontaneously hypertensive rats (SHRSP) and normotensive control Wistar Kyoto rats (WKY) were studied. Endothelium-intact and -removed ring preparations were made from thoracic aorta of SHRSP and WKY, and isometric contraction was observed. Endothelium-intact preparations from WKY showed tension oscillations in response to high concentration of noradrenaline at significantly higher ratio, while only a few endothelium-removed preparation showed tension oscillations in response to low concentration of the drug. Fifteen out of 41 endothelium-removed preparations from SHRSP showed tension oscillations in response to low concentration of noradrenaline but no preparation showed oscillations in response to high concentration of the drug. Seven and 14 out of 42 endothelium-intact preparations from SHRSP showed oscillatory response to low and high concentration of the drug, respectively. Acetylcholine-induced relaxation and tension oscillations, both of which being significantly less in the preparation from SHRSP. Both the endothelium-independent tension oscillations and endothelium-dependent tension oscillations were abolished by removal of extracellular Ca or by verapamil. It is suggested that aortic smooth muscle of SHRSP possesses the property which produced tension oscillations, while the tension oscillations of WKY aorta is endothelium-dependent. The opening of voltage-dependent Ca++ channel of smooth muscle cell membrane which generates rhythmic contraction is increased in the aorta of SHRSP, while the release of endothelium-derived factors which induces rhythmic activities of smooth muscle cell is decreased.

Wnt-1-dependent regulation of local E-cadherin and alpha N-catenin expression in the embryonic mouse brain

E-cadherin is transiently expressed in local regions of the embryonic mouse brain, which include several patchy areas on the mesencephalon and diencephalon and their roof plate and part of cerebellar rudiments. In the present study, we compared this E-cadherin expression with that of Wnt-1, which occurs in specific zones in the embryonic brain, and found certain spatiotemporal relations between them: Wnt-1 expression tended to run parallel or overlap with peripheries of the E-cadherin-positive areas. For example, in the dorsal midline, Wnt-1 was expressed at the middle of the roof plate, while E-cadherin was absent in the middle zone but detected in two arrays of marginal roof plate cells. Furthermore, alpha N-catenin, a cadherin-associated protein, was found to occur at the roof plate of the mesencephalon and diencephalon, coinciding with Wnt-1 expression. The expression of these molecules was then studied in two alleles of the Wnt-1 mutation, Wnt-1sw and Wnt-1neo. In mice homozygous for these mutant genes, E-cadherin expression in the roof plate was up-regulated; the middle E-cadherin-negative zone disappeared. Moreover, E-cadherin expression in the roof plate began earlier in the mutant mice than in wild-type mice. On the contrary, alpha N-catenin expression in the dorsal midline was suppressed in these mutants. These changes in cadherin and catenin expression occurred at the level of mRNA expression. These results suggest that the Wnt-1 signal is, either directly or indirectly, involved in the regulation of expression of E-cadherin and alpha N-catenin in restricted regions of the embryonic brain. This mechanism may contribute to the patterning of the expression of these adhesion-related proteins in the embryonic brain.

Immunoelectron microscopic localization of E-cadherin in dorsal root ganglia, dorsal root and dorsal horn of postnatal mice

Sensory neurons and associated glial cells are known to express the cell-cell adhesion molecule E-cadherin. The cellular and subcellular localization of this molecule in the dorsal root ganglion, dorsal root, and spinal cord of postnatal mice was studied by the pre-embedding immunoelectron microscopic labelling technique. In the dorsal root and the superficial layer of the dorsal horn, a subset of fasciculating unmyelinated axons expressed E-cadherin at their axon-axon contacts at all ages studied, and these axons were clustered together and segregated from E-cadherin-negative axons. In contrast, pre-myelinating large-diameter axons in P2 mice as well as myelinated axons in mice from P14 to adulthood were E-cadherin-negative. Glial cells also expressed E-cadherin: In the dorsal root ganglia, all of the satellite cells expressed E-cadherin at contact sites with neurons, other satellite cells, and basal lamina, at all ages studied. In dorsal roots from P14 to adulthood, myelin-forming Schwann cells expressed E-cadherin at the outer mesaxons and the contact sites with basal lamina. Non-myelin-forming Schwann cells occasionally stained for this molecule at contact sites with the plasma membrane of E-cadherin-positive axons and at other sites. These results strongly suggest that E-cadherin plays an important role in the selective fasciculation of a particular subset of unmyelinated sensory fibres, and also in glial cell contacts.