Evidence for the physiological and pathological roles of adrenomedullin from genetic engineering in mice

Adrenomedullin (AM) has been implicated as having hypotensive as well as protective effects on organs and vessels against different kinds of injuries. To elucidate the in vivo pathophysiological roles of adrenomedullin, we established transgenic mice (AMTg) overexpressing adrenomedullin driven by preproendothelin-1 promoter and adrenomedullin knockout mice (AMKO). Blood pressure in AMTg was significantly lower than that in wild-type mice, and AMTg was significantly resistant to lipopolysaccharide-induced septic shock and vascular injuries. On the other hand, heterozygotes of AMKO, AM(+/-), were fully viable and hypertensive as compared with wild littermates. Mice homozygous for adrenomedullin null mutation (AM-/-) were embryonic lethal, and no embryos could survive beyond the midterm of gestation. Collectively, our findings indicate the indispensable role of adrenomedullin in circulatory homeostasis and the organ protection as well as the fetal morphogenesis and the maintenance of pregnancy.

Elevated sympathetic nervous activity in mice deficient in alphaCGRP

alpha-Calcitonin gene-related peptide (alphaCGRP) is a pleiotropic neuropeptide implicated in a variety of physiological processes. To better understand the biological functions of alphaCGRP, we developed an alphaCGRP-null mouse model using a gene targeting approach. Recordings of mean arterial pressure (MAP) and heart rate (HR) showed that basal MAP and HR were significantly higher in both anesthetized and conscious, unrestrained alphaCGRP-null mice than in corresponding wild-type mice. The elevated MAP in alphaCGRP-null mice was shown to be the result of elevated peripheral vascular resistance by alpha-adrenergic blockade with prazosin and by transthoracic echocardiogram, which revealed no significant differences between alphaCGRP-null and wild-type mice in the stroke volume, fractional shortening, and ejection fraction. Moreover, evaluation of autonomic nervous activity by measuring HR after pretreatment of atropine and/or atenolol and by analyzing arterial baroreceptor reflexes showed sympathetic nervous activity to be significantly elevated in alphaCGRP-null mice; elevated levels of urinary catecholamine metabolites and decreased HR variability in mutant mice were also consistent with that finding. These findings suggest that alphaCGRP contributes to the regulation of cardiovascular function through inhibitory modulation of sympathetic nervous activity.

Altering the GTP binding site of the DNA/RNA-binding protein, Translin/TB-RBP, decreases RNA binding and may create a dominant negative phenotype

The DNA/RNA-binding protein, Translin/Testis Brain RNA-binding protein (Translin/TB-RBP), contains a putative GTP binding site in its C-terminus which is highly conserved. To determine if guanine nucleotide binding to this site functionally alters nucleic acid binding, electrophoretic mobility shift assays were performed with RNA and DNA binding probes. GTP, but not GDP, reduces RNA binding by approximately 50% and the poorly hydrolyzed GTP analog, GTPgammaS, reduces binding by >90% in gel shift and immunoprecipitation assays. No similar reduction of DNA binding is seen. When the putative GTP binding site of TB-RBP, amino acid sequence VTAGD, is altered to VTNSD by site directed mutagenesis, GTP will no longer bind to TB-RBP(GTP) and TB-RBP(GTP) no longer binds to RNA, although DNA binding is not affected. Yeast two-hybrid assays reveal that like wild-type TB-RBP, TB-RBP(GTP) will interact with itself, with wild-type TB-RBP and with Translin associated factor X (Trax). Transfection of TB-RBP(GTP) into NIH 3T3 cells leads to a marked increase in cell death suggesting a dominant negative function for TB-RBP(GTP) in cells. These data suggest TB-RBP is an RNA-binding protein whose activity is allosterically controlled by nucleotide binding.

Vascular abnormalities and elevated blood pressure in mice lacking adrenomedullin gene

BACKGROUND

Adrenomedullin (AM) is a vasodilating peptide involved in the regulation of circulatory homeostasis and in the pathophysiology of certain cardiovascular diseases. Levels of AM are markedly increased in the fetoplacental circulation during pregnancy, although its function there remains unknown. To clarify the physiological functions of AM, we chose a gene-targeting strategy in mice.

METHODS AND RESULTS

Targeted null mutation of the AM gene is lethal in utero: the mortality rate among AM(-/-) embryos was >80% at E13.5. The most apparent abnormality in surviving AM(-/-) embryos at E13.5 to E14.0 was severe hemorrhage, readily observable under the skin and in visceral organs. Hemorrhage was not detectable at E12.5 to E13.0, although the yolk sac lacked well-developed vessels. Electron microscopic examination showed endothelial cells to be partially detached from the basement structure at E12.5 in vitelline vessels and hepatic capillaries, which allowed efflux of protoerythrocytes through the disrupted barrier. The basement membrane was not clearly recognizable in the aorta and cervical artery, and the endothelial cells stood out from the wall of the lumen, only partially adhering to the basement structure. AM(+/-) mice survived to adulthood but exhibited elevated blood pressures with diminished nitric oxide production.

CONCLUSIONS

AM is indispensable for the vascular morphogenesis during embryonic development and for postnatal regulation of blood pressure by stimulating nitric oxide production.

[Anatomic and radiologic considerations of varied appearances of thoracic structures]

The purpose of this pictorial essay was to demonstrate normal chest anatomy and related pathologies on chest radiographs and chest CT images. It is important for the general practitioner to have a clear understanding of anatomy in order to avoid overestimating subtle radiologic findings and to be able to differentiate true pathological lesions. This pictorial essay includes various appearances of pleural fissures, companion shadows of the ribs, and minor structures of the chest walls and mediastinum.

Polypeptide synthesis using an expressed peptide as a building block for condensation with a peptide thioester: application to the synthesis of phosphorylated p21Max protein(1-101)

An expressed peptide proved to be useful as a building block for the synthesis of a polypeptide via the thioester method. A partially protected peptide segment, for use as a C-terminal building block, could be prepared from a recombinant protein; its N-terminal amino acid residue was transaminated to an alpha-oxoacyl group, the side-chain amino groups were then protected with t-butoxycarbonyl (Boc) groups, and. finally, the alpha-oxoacyl group was removed. On the other hand, an O-phosphoserine-containing peptide thioester was synthesized via a solid-phase method using Boc chemistry. These building blocks were then condensed in the presence of silver ions and an active ester component. During the condensation, epimerization at the condensation site could be suppressed by the use of N,N-dimthylformamide (DMF) as a solvent. Using this strategy, a phosphorylated partial peptide of the p21Max protein, [Ser(PO3H2)2.11]-p21Max(1-101), was successfully synthesized.

A new glucose-6-phosphate dehydrogenase variant G6PD Sugao (826C-->T) exhibiting chronic hemolytic anemia with episodes of hemolytic crisis immediately after birth

A case of glucose-6-phosphate dehydrogenase (G6PD) deficiency associated with chronic hemolysis with episodes of hemolytic crisis immediately after birth is reported. The propositus was a 1-month-old Japanese male infant. Molecular analysis of the G6PD gene revealed a novel missense mutation (826C-->4T) in exon 8 predicting a single amino acid substitution, Pro276Ser. The mother was confirmed to be heterozygous for this mutation. We designated this novel class 1 variant as G6PD Sugao. Pro276 is a phylogenetically conserved residue that may play a significant role in dimer formation.

Selective recruitment of CCR6-expressing cells by increased production of MIP-3 alpha in rheumatoid arthritis

Infiltration of various types of leucocytes has been shown to play a crucial role in the pathogenesis of rheumatoid arthritis (RA). Macrophage inflammatory protein-3 alpha (MIP-3 alpha) is a recently identified chemokine which is a selective chemoattractant for leucocytes such as memory T cells, naïve B cells and immature dendritic cells. In this study, we investigated the expression of MIP-3 alpha and its specific receptor CCR6 in the inflamed joints of patients with RA. Increased amounts of MIP-3 alpha were found by ELISA in synovial fluids (SF) of patients with RA. MIP-3 alpha was apparently detected in all synovial tissue specimens of RA patients (n = 6), but it could not be detected in that of osteoarthritis (OA) patients (n = 4). Expression of MIP-3 alpha was detected especially in the sublining layer, and infiltrating mononuclear cells in RA synovial tissue. Gene expression of MIP-3 alpha was also found in six out of 11 RA-synovial fluid cells by RT-PCR. Cultured synovial fibroblasts derived from either RA or OA patients were capable of producing MIP-3 alpha in response to IL-1 beta and TNFalpha in vitro. Furthermore, expression of CCR6 was found in infiltrating mononuclear cells in the cellular clusters and around the vessels of RA synovial tissue. These findings indicate that increased production of MIP-3 alpha may contribute to the selective recruitment of CCR6-expressing cells in RA.

Full implementation of a computerized nursing records system at Kochi Medical School Hospital in Japan

A project to fully implement a novel computerized nursing records system resulted in the standardization of nursing records, reduced the administrative workload for staff, enabled medical staff to know a patient's status at any given time, and improved the quality of nursing care provided to patients. The development process of the computerized nursing records system involved three main steps: 1) the establishment of a new nursing assessment form and introduction of nursing diagnosis into routine work, 2) computerized system design and construction, and 3) the usability check of the computerized nursing records system in a clinical setting for 1 year. The successful development of the computerized nursing records system was based on the following points: 1) the assessment form for nursing diagnosis was improved and the nursing diagnosis was introduced before the computerized system was designed and constructed; 2) full, rather than partial, implementation of the computerized system occurred; 3) existing knowledge of nursing assessments and standard care planning were fully used; 4) registered data were optimally reused upon summarization and readmission to reduce the nurses' workload; and 5) portable computers were introduced to enable simple and quick recording of bedside findings. The routine use of the computerized nursing records system was started in April 2000. More comprehensive investigations during the next 2 to 3 years are necessary to determine how the contents of nursing records can be improved and how much the computerized nursing records system affects the quality of nursing.

A new theory of phylogeny inference through construction of multidimensional vector space

Here, a new theory of molecular phylogeny is developed in a multidimensional vector space (MVS). The molecular evolution is represented as a successive splitting of branch vectors in the MVS. The end points of these vectors are the extant species and indicate the specific directions reflected by their individual histories of evolution in the past. This representation makes it possible to infer the phylogeny (evolutionary histories) from the spatial positions of the end points. Search vectors are introduced to draw out the groups of species distributed around them. These groups are classified according to the nearby order of branches with them. A law of physics is applied to determine the species positions in the MVS. The species are regarded as the particles moving in time according to the equation of motion, finally falling into the lowest-energy state in spite of their randomly distributed initial condition. This falling into the ground state results in the construction of an MVS in which the relative distances between two particles are equal to the substitution distances. The species positions are obtained prior to the phylogeny inference. Therefore, as the number of species increases, the species vectors can be more specific in an MVS of a larger size, such that the vector analysis gives a more stable and reliable topology. The efficacy of the present method was examined by using computer simulations of molecular evolution in which all the branch- and end-point sequences of the trees are known in advance. In the phylogeny inference from the end points with 100 multiple data sets, the present method consistently reconstructed the correct topologies, in contrast to standard methods. In applications to 185 vertebrates in the alpha-hemoglobin, the vector analysis drew out the two lineage groups of birds and mammals. A core member of the mammalian radiation appeared at the base of the mammalian lineage. Squamates were isolated from the bird lineage to compose the outgroup, while the other living reptilians were directly coupled with birds without forming any sister groups. This result is in contrast to the morphological phylogeny and is also different from those of recent molecular analyses.

Trax (translin-associated factor X), a primarily cytoplasmic protein, inhibits the binding of TB-RBP (translin) to RNA

Trax (Translin-associated factor X) has been shown to interact with TB-RBP/Translin by its coimmunoprecipitation and in yeast two-hybrid assays. Here we demonstrate that Trax is widely expressed, does not bind to DNA or RNA, but forms heterodimers with TB-RBP under reducing conditions. The heterodimer of TB-RBP and Trax inhibits TB-RBP binding to RNA, but enhances TB-RBP binding to specific single stranded DNA sequences. The in vitro interactions between TB-RBP and Trax are confirmed by similar interactions in the yeast two-hybrid system. Cell fractionation and confocal microscope studies reveal that Trax is predominantly cytoplasmic. In contrast, TB-RBP is present in both the nuclei and cytoplasm of transfected cells and uses a highly conserved nuclear export signal to exit nuclei. In addition to a leucine zipper, two basic domains in TB-RBP are essential for RNA binding, but only one of these domains is needed for DNA binding. Trax restores DNA binding to TB-RBP containing an altered form of this domain. These data suggest that Trax-TB.RBP interactions modulate the DNA- and RNA-binding activity of TB-RBP.

Bronchiolitis obliterans with organizing pneumonia versus chronic eosinophilic pneumonia: high-resolution CT findings in 81 patients

OBJECTIVE

The objective of this research was to compare high-resolution CT findings of bronchiolitis obliterans with organizing pneumonia (BOOP) with those of chronic eosinophilic pneumonia (CEP) and to determine whether high-resolution CT can differentiate the two.

MATERIALS AND METHODS

We retrospectively reviewed high-resolution CT scans of 38 patients with BOOP and 43 patients with CEP. Without knowledge of the diagnosis, two radiologists evaluated the frequency and distribution of high-resolution CT findings in both groups of patients and made a diagnosis using a three-point scale of confidence.

RESULTS

Nodules, nonseptal linear or reticular opacities, and bronchial dilatation were significantly more common in BOOP than in CEP (31.6% vs. 4.7%, p < 0.005; 44.7% vs. 9.3%, p < 0.001; and 57.9% vs. 25.6%, p < 0.005, respectively). Septal line thickening was more frequent in CEP than in BOOP (72.1% vs. 39.5%, p < 0.005). Peribronchial distribution of consolidation was more frequent in BOOP than in CEP (28.9% vs. 9.3%, p < 0.05). A correct diagnosis was made in 69.7% of cases, and the diagnostician was confident in 21.7%. Interobserver agreement was good (kappa = 0.6).

CONCLUSION

Although several of the high-resolution CT findings of BOOP and CEP are different, these diseases are differentiated with confidence in only a small percentage of cases.

Up-regulation of prostaglandin E receptor EP2 and EP4 subtypes in rat synovial tissues with adjuvant arthritis

To evaluate the role of the prostaglandin E receptor (EP) subtypes in the development of inflammatory synovitis, we examined EP subtype mRNA distribution in the synovial tissue of rats with adjuvant arthritis and the effect of selective EP agonists on cytokine production by cultured rat synovial cells. We used reverse transcriptase-polymerase chain reaction (RT-PCR) and in situ hybridization to measure the level of EP subtype (EP1, EP2, EP3, and EP4) mRNA expression in synovial tissues and cultured synovial cells from the arthritic joints of rats. RT-PCR and ELISA were used to analyse the effects of two selective EP agonists on IL-6 production by cultured rat synovial cells. EP2 and EP4 mRNA expression in inflamed synovial tissues was up-regulated. EP2 and EP4 mRNA were co-expressed in synovial macrophages and fibroblasts in inflamed tissues. EP4 and EP2 agonists both inhibited IL-1-induced IL-6 production. Our results suggest that prostaglandin E2 regulates the functions of synovial macrophages and fibroblasts through EP2 and EP4, which are induced by inflammatory stimuli in rats with adjuvant arthritis.

Diet-induced hyperhomocysteinemia exacerbates neointima formation in rat carotid arteries after balloon injury

BACKGROUND

Increasing evidence indicates that elevated plasma homocysteine levels are associated with an increased risk of atherosclerosis and endothelial dysfunction, although little specific information on the mechanisms responsible for the atherogenic effects of homocysteine or on the in vivo contribution made by hyperhomocysteinemia to atherosclerosis is currently available. Because homocysteine is known to exert a direct inhibitory effect on endothelial cell growth in vitro, we hypothesized that this effect contributes to the progression of atherosclerotic lesions initiated by endothelial damage caused by mechanical injury.

METHODS AND RESULTS

We prepared diet-induced hyperhomocysteinemic rats in which neointima formation after balloon injury to the common carotid artery was assessed. Moderate hyperhomocysteinemia (plasma homocysteine levels 3- to 4-fold higher than control) significantly exacerbated neointima formation. Oral administration of folate, which had a homocysteine-lowering effect, diminished neointima formation induced by moderate hyperhomocysteinemia. Furthermore, the attenuation of reendothelialization was shown in diet-induced hyperhomocysteinemic rats with Evans blue staining.

CONCLUSIONS

Diet-induced hyperhomocysteinemia, even mild to moderate, exacerbates neointima formation after denuding injury, making hyperhomocysteinemia a likely risk factor for postangioplasty restenosis. It may be mediated through an inhibitory effect of homocysteine on reendothelialization. Homocysteine lowering with folate supplementation can effectively ameliorate the detrimental effects of moderate hyperhomocysteinemia. Clinical trials would seem to be warranted.

Induction of IL-6 via the EP3 subtype of prostaglandin E receptor in rat adjuvant-arthritic synovial cells

OBJECTIVE AND DESIGN

This study investigated the role of the prostaglandin E receptor EP3 subtype in the development of inflammatory synovitis.

MATERIALS AND METHODS

We examined the EP3 mRNA expression in the synovial tissue of rats with adjuvant arthritis and the effect of selective EP agonists on IL-6 production by cultured rat synovial cells.

RESULTS

Of the two rat EP3 isoforms, rEP3B mRNA but not rEP3A mRNA was expressed in rat synovial cells. RT-PCR and ELISA were used to analyze the effects of selective EP3 agonist (ONO-AE-248) on IL-6 production by rat cultured synovial cells. This selective EP3 agonist induced IL-6 production by rat synovial cells in a time- and dose-dependent manner.

CONCLUSIONS

Our results suggest that PGE2 upregulates IL-6 production by synovial macrophages and fibroblasts through rEP3B in rats with adjuvant arthritis.

Induction of heme oxygenase-1 can act protectively against cardiac ischemia/reperfusion in vivo

Enhanced production of reactive oxygen species plays a role in myocardial injury following ischemia/reperfusion. Heme oxygenase-1 (HO-1) is a heme-catabolizing enzyme that is induced by and acts against oxidant-induced tissue injury. We examined whether HO-1 expression was regulated following ischemia and reperfusion in the rat heart. HO-1 expression increased as early as 24 h after reperfusion. Strong HO-1 expression was seen in monocytes/macrophages and myofibroblasts. Next, we examined whether the induction of HO-1 could ameliorate cardiac injury following ischemia/reperfusion. Intraperitoneal hemin injection (30 mg/kg/day) for 2 days prior to the operation resulted in an about 2.8-fold increase in HO-1 expression in the rat heart. Hemin treatment significantly decreased infarct area (6 +/- 2%) compared to the control (21 +/- 2%), which was reversed by the coadministration of an HO inhibitor in a dose-dependent manner. Our data suggest that induction of HO-1 can reduce the cardiac injury in vivo following ischemia/reperfusion.

[Anesthetic management of tracheal stent insertion under total intravenous anesthesia--a report of two cases]

Tracheal stent insertion is a useful method for patients with malignant tracheal stenosis. Expandable metal stents were inserted in two patients with severe dyspnea due to tracheal stenosis caused by lung cancer and esophageal cancer. The tracheas were intubated after spraying the pharynx with 4% lidocaine solution. The respiration was assisted. Anesthesia was maintained by intravenous propofol. There were no episodes of coughing during and after the procedure.

Dental caries susceptibility in mice is closely linked to the H-2 region on chromosome 17

The generation of dental caries in humans is thought to be regulated by many intrinsic and social factors. In this study, we examined the effect of MHC on susceptibility to dental caries in mice. The mean carious score of BALB.K/Ola, a H-2 congenic strain in which the H-2 region derived from C3H/HeJ (H-2(k/k)) is introduced into BALB/cJ (H-2(d/d)), was markedly reduced as compared with that of its recipient strain (BALB/cJ). Mating experiments confirmed a strong genetic linkage between H-2 haplotype and caries susceptibility. These results demonstrate that one of the genetic factors of the susceptibility in the mouse is mapped within the H-2 region. This finding of a host genetic factor influencing the generation of dental caries will help in developing clinical preventive strategies.

Arborcandins A, B, C, D, E and F, novel 1,3-beta-glucan synthase inhibitors: production and biological activity

Arborcandins A, B, C, D, E and F, which possess potent 1,3-beta-glucan synthase inhibitory activity, were isolated from the culture broth of a filamentous fungus, strain SANK 17397. Arborcandins are novel cyclic peptides, that are structurally different from known glucan synthase inhibitors such as echinocandins. The 1,3-beta-glucan synthases of Candida albicans and Aspergillus fumigatus were inhibited by arborcandins with IC50 ranging from 0.012 to 3 microg/ml. The apparent Ki value of arborcandin C for C. albicans and A. fumigatus were 0.12 microM and 0.016 microM, respectively. The inhibition against these two 1,3-beta-glucan synthases by arborcandin C was noncompetitive. These compounds exhibited potent fungicidal activity against Candida spp. with MIC ranging from 0.25 to 8 microg/ml. The growth of A. fumigatus was suppressed by arborcandins with concentrations ranging from 0.063 to 4 microg/ml.

[Anesthetic management of a patient with Brugada syndrome]

Brugada syndrome is characterized by right bundle-branch block, ST elevation in leads V 1 through V 3 and normal QT interval. Ventricular fibrillation frequently occurs in patients with Brugada syndrome. There have been few reports of anesthetic management of Brugada patients. We managed a 47-year-old man with Brugada syndrome, who underwent hemilaminectomy under general anesthesia, without untoward cardiovascular events. Potential problems in anesthetic management of patients with Brugada syndrome are also discussed.

Role of endothelin-1 in stress response in the central nervous system

Endothelin (ET)-1 is a 21-amino acid peptide that induces a variety of biological activities, including vasoconstriction and cell proliferation, and its likely involvement in cardiovascular and other diseases has recently led to broad clinical trials of ET receptor antagonists. ET-1 is widely distributed in the central nervous system (CNS), where it is thought to regulate hormone and neurotransmitter release. Here we show that CNS responses to emotional and physical stressors are differentially affected in heterozygous ET-1-knockout mice, which exhibited diminished aggressive and autonomic responses toward intruders (emotional stressors) but responded to restraint-induced (physical) stress more intensely than wild-type mice. This suggests differing roles of ET-1 in the central pathways mediating responses to different types of stress. Hypothalamic levels of ET-1 and the catecholamine metabolite 3-methoxy-4-hydroxyphenylglycol (MHPG) were both increased in wild-type mice subjected to intruder stress, whereas MHPG levels were not significantly affected in ET-1-knockout mice. Furthermore, immunohistochemical analysis showed that ET-1 and tyrosine hydroxylase, an enzyme in the catecholamine synthesis pathway, were colocalized within certain neurons of the hypothalamus and amygdala. Our findings suggest that ET-1 modulates central coordination of stress responses in close association with catecholamine metabolism.

Design and NMR analysis of HDV ribozymes for structural investigation

Three variants of minimized hepatitis delta virus (HDV) RNA ribozyme systems (Rz-1 to approximately Rz-3) (Fig. 1) were designed on the basis of the "pseudoknot" structure model and synthesized. Rz-1 is a cis-acting ribozyme system (a cleaved form, 56-mer) in which stem IV is deleted from the active domain of genomic HDV RNA. Rz-1 was uniformly labeled with stable isotopes, 13C and 15N. The 2D-NOESY and 2D-HSQC data for Rz-1 suggest that Rz-1 forms the pseudoknot structure and G38 which is opposite to the cleavage site makes a base-pair. Rz-2 is a trans-acting ribozyme system which consists of three RNA oligomer strands (substrate: 8-mer, the cytidine residue at the cleavage site is replaced by 2'-O-methylcytidine; enzyme: 16-mer plus 35-mer). Rz-3 is a ribozyme in which the three RNA strands of Rz-2 are connected. It turns out that Rz-3 forms an inactive structure with low cleavage activity (k(obs) = 0.009) and final cleavage yield (6%). Rz-3 has the highest cleavage activity at pH 5.5. The optimal activity at acidic pH is similar to that of the wild type ribozyme. We also synthesized and examined the activity and structure of Rz-4 (designed by Perrotta and Been) which consists of two RNA strands (1).