Trends in Place of Death in a Super-Aged Society: A Population-Based Study, 1998-2017

Background: Globally, the number of deaths is estimated to increase to 74 million per year by 2030. Place of death (PoD) is increasingly being recognized as an important aspect of end-of-life care. However, recent trends in PoD in Japan, one of the super-aged societies, are unknown. Objective: To analyze trends in PoD in Japan over two decades. Design: Population-based retrospective observational study. Setting: All deaths reported in Japan, 1998-2017. PoD was defined as hospital, nursing home, or own home. Results: All Japanese decedents (∼22.6 million) over the past 20 years were analyzed. The proportion of hospital deaths was consistently high (>80%), with a significant decreasing trend from the mid-2000s. Although the proportion of deaths at home decreased in the first half of the study period, they later increased. There was a low proportion of deaths in nursing homes compared to other places of death; however, the proportion increased continually throughout the study period, particularly among women. In 2015, more women died in nursing homes than at home. Although the proportion of hospital deaths declined in the second half of the study period, their overall number continued to increase, reflecting an increase in total deaths in Japan. Conclusions: This study highlighted rapid changes in trends in PoD in Japan, and the need to consider affordable end-of-life care in Japan as well as other countries with aging populations. The findings from this long-term epidemiological study provide important insights on this issue.

Trends in Polypharmacy in Japan: A Nationwide Retrospective Study

OBJECTIVES

To describe and examine trends in polypharmacy according to age in Japan from 2010 to 2016.

DESIGN

Retrospective observational study.

SETTING

Outpatient settings.

PARTICIPANTS

Japanese individuals aged 20 and older.

MEASUREMENTS

We analyzed pharmacy claims data that the Japanese Ministry of Health, Labor, and Welfare provided in the Survey of Medical Care Activities in Public Health Insurance from 2010 to 2016. The use of 5 or more oral prescription medications per month was defined as polypharmacy and of 10 or more as excessive polypharmacy. Regression analysis was used to estimate trends in polypharmacy with annual percentage changes. Using number of medications (polypharmacy vs excessive polypharmacy), trends in polypharmacy and crude and age-adjusted rates of polypharmacy per 1,000 persons were calculated according to year and age group (20-34, 35-49, 50-64, 65-79, ≥ 80).

RESULTS

We analyzed 240 million pharmacy claims data. The age-adjusted monthly prevalence rate of polypharmacy increased from 85.2 to 93.8 per 1,000 persons per month and of excessive polypharmacy from 13.6 to 14.0 per 1,000 persons per month from 2010 to 2016 in the entire study population. The highest rate of polypharmacy (per 1,000 persons) was observed in 2016 in those aged 80 and older (326.8), followed by those aged 65 to 79 (167.3). The polypharmacy rate increased by 6.3% (95% confidence interval (CI)=4.0-8.7) per year from 2010 to 2012, then decreased by 0.7% (95% CI=-1.3-0.0) per year from 2012 to 2016. The rate of excessive polypharmacy increased by 4.5% (95% CI=1.1-8.0) per year from 2010 to 2013 and then decreased by 3.7% (95% CI=-6.7 to -0.6) per year from 2013 to 2016.

CONCLUSION

The overall trend of polypharmacy in Japan increased during the study period, although the increase ceased in 2013 and then declined from 2013 to 2016. Policy changes in Japan might be responsible for some of the changes. J Am Geriatr Soc 66:2267-2273, 2018.

Trends in the medication reviews of community pharmacies in Japan: a nationwide retrospective study

Background The trends in medication reviews made by community pharmacies in Japan are currently unknown. Objective We aimed to comprehensively describe the national trends in medication reviews in Japan's community pharmacies in the backdrop of the country's ageing population. Setting Community pharmacies in Japan. Methods We analysed national health insurance claims data for 2010-2015. These data were provided by the Ministry of Health, Labour and Welfare as part of the Survey of Medical Care Activities in Public Health Insurance. Main outcome measures The national trends in community pharmacy visits involving medicine dispensing and medication reviews that involve consultations with a physician. Results Among the 365 million pharmacy visits for 2010-2015, we identified 373,429 medication reviews accompanied by consultations with a physician. The pharmacy visit rate per 1000 population increased from 427.2 in 2010 to 483.7 in 2015. Medication reviews also increased from 407 per million pharmacy visits in 2010 to 1445 in 2015. Among the 373,429 medication reviews during the study period, the prescription was changed through collaboration with a physician 338,982 times (90.4%). The proportion of medication review acceptance increased from 80.6% in 2010 to 94.8% in 2015. The prescription change rate was higher among older patients than among younger ones. Conclusions Medication reviews by community pharmacists involving consultations with a physician increased in Japan from 2010 to 2015, as did prescription changes following these reviews.

Detection of anti-Nogo receptor autoantibody in the serum of multiple sclerosis and controls

OBJECTIVES

A myelin-associated neurite outgrowth inhibitor Nogo-A plays a key role in inhibition of axonal regeneration. Axonal damage beginning at the early stage of multiple sclerosis (MS) is responsible for permanent neurological deficits, although its molecular mechanism remains unknown. The aim was to study the prevalence of autoantibodies against Nogo-A and Nogo receptor (NgR) in the serum of MS.

METHODS

The antibodies were identified in the serum of 30 MS patients, 22 patients with non-MS other neurological diseases (OND), and 22 healthy control (HC) subjects by Western blot using recombinant human Nogo-A-specific segment (NAS), the shared segment of Nogo-A and -B (NAB), Nogo-66 (N66), the non-glycosylated form of NgR, the glycosylated NgR (NgR-Fc), and myelin oligodendrocyte glycoprotein (MOG).

RESULTS

None showed immunoglobulin G (IgG) antibodies against NAS or NAB. In contrast, 30% of MS, 23% of OND and 32% of HC subjects exhibited anti-N66 IgG, while 27% of MS, 27% of OND and 18% of HC showed anti-MOG IgG. None of HC but 33% of MS and 14% of OND showed anti-non-glycosylated NgR IgG. Furthermore, 60% of MS, 18% of OND and 14% of HC showed anti-NgR-Fc IgG.

CONCLUSIONS

Because IgG autoantibodies against N66, NgR and MOG are often detected in the serum of MS and controls, they do not serve as an MS-specific marker.

Imaging intracranial haemangiopericytomas: study of seven cases

Imaging features of intracranial haemangiopericytomas are similar to those of meningiomas. Preoperative identification of these tumours is important because of their aggressive nature, high rate of local recurrence and propensity for late metastasis. We reviewed the CT, MRI and angiographic findings in seven pathologically proved haemangiopericytomas, to determine if imaging characteristics might distinguish them from meningiomas. None showed hyperostosis or tumour calcification. All showed marked enhancement. Five had prominent internal signal voids, suggesting feeding arteries. On angiography, one had only pial-cortical supply but six also had meningeal supply; all showed a persistent stain. Only one had multiple "corkscrew" feeding vessels.

Induction of macrophage inflammatory protein-1alpha and vascular endothelial growth factor during inflammatory neovascularization in the mouse cornea

We predicted that the appearance of macrophages in inflammatory areas is necessary for angiogenic responses in various inflammatory diseases. Using a mouse inflammatory corneal model in which model mouse corneas were cauterized with silver nitrate, we examined the infiltration of macrophages immunohistochemically and the total area of neovascularization quantitively. The expression of macrophage inflammatory protein-1alpha (MIP-1alpha) and vascular endothelial growth factor (VEGF) levels were also examined. A day after cauterization, short capillaries began to develop into the corneal stroma, and after 4 or 5 days the neovascularization became maximal and then began to regress. The number of macrophages within the cauterized cornea increased to a maximum at day 3 and began to decrease at day 5. The number of infiltrated macrophages reached maximum at day 3. Both MIP-1alpha and VEGF protein levels increased markedly immediately after the chemical cauterization, and production of MIP-1alpha (85.8 pg/4 corneas) and VEGF (206.5 pg/4 corneas) was maximal at 1 day and 0.5 day after cauterization, respectively. MIP-1alpha and VEGF mRNA levels also increased at 0.5 day after cauterization. In situ hybridization showed that MIP-1alpha was localized in corneal epithelial cells, and VEGF was localized in corneal epithelial cells and infiltrating inflammatory cells. MIP-1alpha and VEGF may have an important role in recruiting macrophages and neovascularization.

Cholesterol granuloma in the petrous apex: case report and review

Cholesterol granuloma in the petrous apex presents with various symptoms of cranial nerve dysfunction, so the selection for surgical treatment remains controversial. We report a 41-year-old woman with a cholesterol granuloma at the left petrous apex, which was totally resected via a combined middle fossa and posterior transpetrosal approach. In a review of 92 cases, including our case, treated for petrous apex cholesterol granuloma between 1990 and 2001, 38 were men (41.3%) and 54 were women (58.7%). The mean age of these patients was 37.4 years (males were 35.2 years, females were 39.4 years). The most common presenting clinical symptom was hearing loss due to dysfunction of cranial nerve VIII. Seventy-nine patients, including our case, underwent operation, and 13 patients were managed without surgery. The most frequently selected surgical approach was middle cranial fossa approach. Revision surgery (including the 2 cases who underwent revision twice and three times) was performed in 12 patients (15.2%). In 92 cases, all of those who underwent total removal have not shown re-accumulation of cyst contents. On the other hand, 11.4% of the patients with or without permanent drainage route proceeded by subtotal removal of the cyst wall needed revision surgery because of stenosis of the drainage route. Therefore we conclude that the most important treatment for the prevention of re-accumulation of cyst contents may be the extent of the cyst wall resection rather than the establishment of permanent drainage route.

Reconstitution in lipid bilayer of smooth muscle cation channels activated through a GTP-binding protein

Reconstitution of G-protein-coupled receptor activated cation channels into the lipid bilayer was attempted with plasma membrane vesicles prepared from guinea-pig ileal smooth muscle using the purification technique previously applied to the large conductance Ca2+-dependent and ATP-sensitive K+ channels (Toro et al., 1990). Under Na+-rich conditions, incorporation of plasma membrane vesicles into the bilayer produced GTPgammaS (100 microM)-activatable channel activities that are inhibited by GDPbetaS (1 mM), sensitive to Ca2+ and enhanced by depolarization. The reversal potential and unitary conductance (tens of picosiemens) of these channels varied in a manner dependent on Na+ concentration, but not affected by Cl-. These results strongly indicate that the reconstituted channels activated by GTPgammaS belong to a class of voltage-dependent, Ca2+-sensitive cation-selective channels that are activated through a G-protein, and correspond most likely to the muscarinic receptor-activated cation channels previously identified in the same preparation. These results also suggest potential usefulness of bilayer incorporation technique to investigate the receptor-operated cation channels in smooth muscle.

The transient receptor potential protein homologue TRP6 is the essential component of vascular alpha(1)-adrenoceptor-activated Ca(2+)-permeable cation channel

The Drosophila transient receptor potential protein (TRP) and its mammalian homologues are thought to be Ca(2+)-permeable cation channels activated by G protein (G(q/11))-coupled receptors and are regarded as an interesting molecular model for the Ca(2+) entry mechanisms associated with stimulated phosphoinositide turnover and store depletion. However, there is little unequivocal evidence linking mammalian TRPs with particular native functions. In this study, we have found that heterologous expression of murine TRP6 in HEK293 cells reproduces almost exactly the essential biophysical and pharmacological properties of alpha(1)-adrenoceptor-activated nonselective cation channels (alpha(1)-AR-NSCC) previously identified in rabbit portal vein smooth muscle. Such properties include activation by diacylglycerol; S-shaped current-voltage relationship; high divalent cation permeability; unitary conductance of 25 to 30 pS and augmentation by flufenamate and Ca(2+); and blockade by Cd(2+), La(3+), Gd(3+), SK&F96365, and amiloride. Reverse transcriptase-polymerase chain reaction and confocal laser scanning microscopy using TRP6-specific primers and antisera revealed that the level of TRP6 mRNA expression was remarkably high in both murine and rabbit portal vein smooth muscles as compared with other TRP subtypes, and the immunoreactivity to TRP6 protein was localized near the sarcolemmal region of single rabbit portal vein myocytes. Furthermore, treatment of primary cultured portal vein myocytes with TRP6 antisense oligonucleotides resulted in marked inhibition of TRP6 protein immunoreactivity as well as selective suppression of alpha(1)-adrenoceptor-activated, store depletion-independent cation current and Ba(2+) influx. These results strongly indicate that TRP6 is the essential component of the alpha(1)-AR-NSCC, which may serve as a store depletion-independent Ca(2+) entry pathway during increased sympathetic activity.

Effects of superoxide generating systems on muscle tone, cholinergic and NANC responses in cat airway

To study the possible role of reactive oxygen species in airway hyperreactivity, we examined the effects of the superoxide anion radical (O(2)(-)) generating systems, pyrogallol and xanthine with xanthine oxidase, on muscle tone, excitatory and inhibitory neurotransmission in the cat airway. Smooth muscle contraction or non-adrenergic non-cholinergic (NANC) relaxation evoked by electrical field stimulation (EFS) were measured before or after O(2)(-) generating systems with or without diethydithiocarbamic acid (DEDTCA), an inhibitor of endogenous superoxide dismutase (SOD). Resting membrane potential or excitatory junction potential (EJP) were also measured in vitro. Both pyrogallol and xanthine/xanthine oxidase produced biphasic changes in basal and elevated (by 5-HT) muscle tone. After SOD pretreatment, both systems consistently produced a prolonged contraction, thereby indicating that O(2)(-) was converted to H(2)O(2) by the action of SOD and as a result the actions of O(2)(-) were lost but those of H(2)O(2) introduced. The O(2)(-) showed no significant effect on smooth muscle contraction or EJP evoked by EFS, however after DEDTCA pretreatment, it evoked initial enhancement followed by suppression of the contraction and EJP. DEDTCA pretreatment ameliorated the inhibitory action of pyrogallol and xanthine/xanthine oxidase on the NANC relaxation, probably because O(2)(-) could combine with endogenous NO to form peroxynitrite. These results indicate that the O(2)(-) generating systems have multiple actions, presumably due to the presence and simultaneous action of at least two different reactive oxygen species (O(2)(-) and H(2)O(2)). While H(2)O(2) seems to be responsible for elevation of muscle tone and augmentation of smooth muscle contraction by EFS, O(2)(-) inhibits muscle tone, cholinergic and NANC neurotransmission.

B(1) and B(2) bradykinin receptors on adventitial fibroblasts of cerebral arteries are coupled to recombinant eNOS

Our previous ex vivo and in vivo studies reported that expression of the recombinant endothelial nitric oxide (NO) synthase (eNOS) gene in adventitial fibroblasts recovers NO production in arteries without endothelium in response to bradykinin. The present study was designed to characterize subtypes of bradykinin receptors on adventitial fibroblasts coupled to the activation of recombinant eNOS. Endothelium-denuded segments of canine basilar arteries were transduced with beta-galactosidase (beta-Gal) gene or eNOS gene ex vivo, using a replication-defective adenoviral vector (10(10) plaque-forming units/ml) for 30 min at 37 degrees C. Twenty-four hours later, isometric force recording or cGMP measurement was carried out. B(1) bradykinin receptor agonist (des-Arg(9)-bradykinin, 10(-10)-10(-8) mol/l) did not significantly affect vascular tone in control or beta-Gal gene-transduced canine basilar arteries without endothelium. In contrast, this agonist caused concentration-dependent relaxations in recombinant eNOS gene-transduced arteries without endothelium. Relaxations to B(1) receptor agonist in the eNOS arteries were abolished by B(1) receptor antagonist (des-Arg(9)-[Leu(8)]bradykinin, 6 x 10(-9) mol/l) but not by B(2) receptor antagonist (Hoe-140, 5 x 10(-8) mol/l). Bradykinin did not significantly alter vascular tone in control or beta-gal arteries without endothelium, whereas this peptide (10(-11)-10(-8) mol/l) induced concentration-dependent relaxations, as well as an increase in cGMP formation in endothelium-denuded eNOS-transduced arteries. Stimulatory effects of bradykinin were prevented in the presence of a B(2) receptor antagonist but not in the presence of a B(1) receptor antagonist. B(1) and B(2) receptor antagonists had no effect on relaxations to substance P, confirming the selectivity of the compounds. Our results suggest that B(1) and B(2) bradykinin receptors are coupled to activation of recombinant eNOS expressed in adventitial fibroblasts.

Effects of recombinant eNOS gene expression on reactivity of small cerebral arteries

Resistance arteries are an important target for vascular gene therapy because they play a key role in the regulation of tissue blood flow. The present study was designed to determine the effects of recombinant endothelial (e) nitric oxide synthase (NOS) gene expression on vasomotor reactivity of small brain stem arteries (internal diameter, 253 +/- 2.5 microm). Arterial rings were exposed ex vivo to an adenoviral vector (10(9) and 10(10) plaque-forming units/ml) encoding eNOS gene or beta-galactosidase gene. Twenty-four hours after transduction, vascular function was examined by isometric force studies. Transgene expression was evident mainly in adventitia. In arteries with endothelium transduced with eNOS gene but not with control beta-galactosidase gene, relaxations to bradykinin and substance P were significantly augmented. Removal of endothelium abolished relaxations to bradykinin and substance P in control and beta-galactosidase arteries. However, in endothelium-denuded arteries transduced with recombinant eNOS, bradykinin and substance P caused relaxations that were abolished in the presence of the NOS inhibitor N(G)-nitro-L-arginine methyl ester. In control arteries, endothelium removal augmented relaxations to the nitric oxide donors sodium nitroprusside and diethylamine NONOate. This augmentation was absent in eNOS gene-transduced arteries without endothelium. Our results suggest that, in small brain stem arteries, expression of recombinant eNOS increases biosynthesis of nitric oxide. Adventitia of small arteries is a good target for expression of recombinant eNOS. Genetically engineered adventitial cells may serve as a substitute source of nitric oxide in cerebral arteries with dysfunctional endothelium.

Heterooligomer of type 1 and type 2 inositol 1, 4, 5-trisphosphate receptor expressed in rat liver membrane fraction exists as tetrameric complex

Functional IP(3)-sensitive intracellular Ca(2+) release channel is considered to be a tetramer of IP(3)R. Heterooligomeric complexes composed of distinct types of IP(3)R have been reported, however, crucial evidences for them being tetramer have not appeared. Here we report that the heterooligomer composed of IP(3)R1 and IP(3)R2 also exists as tetramer. Cross-linked heterooligomer was immunoprecipitated with IP(3)R1-specific antibody and detected by agarose-PAGE/Western blot analysis with IP(3)R2-specific antibody. Tetramer, trimer, dimer, and possibly monomer were detected. The trimer, dimer, and monomer were likely to be originated from the tetramer, since: (1) the immunoprecipitating antibody (IP(3)R1-specific) does not recognize IP(3)R2, therefore IP(3)R2 monomer itself could not have been immunoprecipitated; and (2) tetramer was the major native product of IP(3)R complex containing type 2 isoform in liver membrane fraction. Thus we conclude tetramer is the native form of heterooligomer composed of IP(3)R1 and IP(3)R2.

The prostaglandin E series modulates high-voltage-activated calcium channels probably through the EP3 receptor in rat paratracheal ganglia

The modulation of high-voltage-activated (HVA) Ca2+ channels by the prostaglandin E series (PGE1 and PGE2) was studied in the paratracheal ganglion cells. Prostaglandin E1, E2, STA2 (a stable analogue of thromboxane A2), 17-phenyl-trinor-PGE2 (an EP1-selective agonist) and sulprostone (an EP3-selective agonist) inhibited the HVA Ca2+ current (HVA ICa) dose-dependently, and the rank order of potency to inhibit HVA Ca2+ channels was sulprostone>PGE2, PGE1>STA2>>17-phenyl-trinor-PGE2. SC-51089 (10(-5) M), a selective EP1-receptor antagonist, showed no effect on the PGE1- or PGE2-induced inhibition of the HVA ICa, thereby indicating that PGE1- and PGE2-induced inhibition of the HVA Ca2+ channels is possibly mediated by the EP3 receptor. The PGE1-sensitive component of the current was markedly reduced in the presence of omega-conotoxin-GVIA (3x10(-6) M), but not with nifedipine (3x10(-6) M). PGE1 and PGE2 also inhibited the remaining ICa in a saturating concentration of nifedipine, omega-conotoxin-GVIA and omega-conotoxin-MVIIC, suggesting that R-type Ca2+ channels are involved. The inhibitory effect of PGE1 or sulprostone was prevented by pretreatment with pertussis toxin [islet activating protein (IAP)] or phorbol-12-myristate-13-acetate (PMA), and the protein kinase C (PKC) inhibitor chelerythrine blocked the action of PMA. It was concluded that PGE1 selectively reduces both N- and R-type Ca2+ currents by activating a G-protein probably through the EP3 receptor in paratracheal ganglion cells.

Predominant distribution of nifedipine-insensitive, high voltage-activated Ca2+ channels in the terminal mesenteric artery of guinea pig

We have found nifedipine-insensitive (NI), rapidly inactivating, voltage-dependent Ca2+ channels (current, NI-I(Ca)) with unique biophysical and pharmacological properties in the terminal branches of guinea pig mesenteric artery, by using a whole-cell mode of the patch-clamp technique. The fraction of NI-I(Ca) appeared to increase dramatically along the lower branches of mesenteric artery, amounting to almost 100% of global I(Ca) in its periphery. With 5 mmol/L Ba2+ as the charge carrier, NI-I(Ca) was activated with a threshold of -50 mV, peaked at -10 mV, and was half-activated and inactivated at -11 and -52 mV, respectively, generating a potential range of constant activation near the resting membrane potential. The NI-I(Ca) was rundown resistant, was not subject to Ca(2+)-dependent inactivation, and exhibited the pore properties typical for high voltage-activated Ca2+ channels; Ba2+ is approximately 2-fold more permeable than Ca2+, and Cd2+ is a better blocker than Ni2+ (IC(50), 6 and 68 micromol/L, respectively). Relatively specific blockers for N- and P/Q-type Ca2+ channels such as omega-conotoxins GVIA and MVIIC (each 1 micromol/L) and omega-agatoxin IVA (1 micromol/L) were ineffective at inhibiting NI-I(Ca), whereas nimodipine partially (10 micromol/L; approximately 40%) and amiloride potently ( approximately 75% with 1 mmol/L; IC(50); 107 micromol/L) blocked the current. Although these properties are reminiscent of R-type Ca2+ channels, expression of the alpha(1E) mRNA was not detected using reverse transcriptase-polymerase chain reaction. These results strongly suggest the predominant presence of NI, high voltage-activated Ca2+ channels with novel properties, which may be abundantly expressed in peripheral small arterioles and contribute to their tone regulation.

Adventitial expression of recombinant endothelial nitric oxide synthase gene reverses vasoconstrictor effect of endothelin-1

The present study was designed to determine the effect of recombinant endothelial nitric oxide synthase (eNOS) gene expression on reactivity of canine basilar arteries to endothelin-1 (ET-1). Experiments were performed ex vivo. The arteries were exposed (30 minutes at 37 degrees C) to adenoviral vectors encoding eNOS gene (AdCMVeNOS) or beta-galactosidase reporter gene (AdCMVbeta-Gal). Twenty-four hours after transduction, transgene expression was evident mainly in the vascular adventitia. Rings of control (nontransduced), AdCMVbeta-Gal- and AdCMVeNOS-transduced arteries with and without endothelium were suspended for isometric tension recording. Levels of guanosine 3',5'-cyclic monophosphate (cGMP) were measured by radioimmunoassay. During contractions to uridine 5'-triphosphate, ET-1 (10(-10) to 3x10(-9) mol/L) caused further increase in tension in control and AdCMVbeta-Gal-transduced arteries. In contrast, ET-1 caused concentration-dependent relaxations of AdCMVeNOS-transduced arteries. The relaxations to ET-1 in AdCMVeNOS-transduced arteries were endothelium-independent. They were abolished by N(G)-nitro-L-arginine methyl ester or by chemical treatment of adventitia with paraformaldehyde before gene transfer. ET-1 (10(-9) mol/L) significantly increased intracellular cGMP levels in AdCMVeNOS-transduced arteries without endothelium. In arteries transduced with AdCMVeNOS, higher concentrations (10(-9) to 3x10(-8) mol/L) of ET-2 also caused relaxations, whereas ET-3 and sarafotoxin, a selective ET(B) receptor agonist, did not produce any relaxations. The relaxations to ET-1 in AdCMVeNOS-transduced arteries were strongly reduced by BQ-123 (10(-7) mol/L), an ET(A) receptor antagonist, but were not affected by BQ-788 (3x10(-7) mol/L), an ET(B) receptor antagonist. These results suggest that genetically modified adventitia can produce nitric oxide and cause relaxations in response to ET-1 via activation of ET(A) receptors. Our findings support a novel concept that successful transfer and expression of recombinant eNOS gene can lead to a qualitative change in responsiveness to vasoconstrictor substances.

Adventitia-dependent relaxations of canine basilar arteries transduced with recombinant eNOS gene

We recently reported that expression of recombinant endothelial nitric oxide (NO) synthase (eNOS) gene in adventitial fibroblasts restores NO formation in canine cerebral arteries without endothelium in response to bradykinin ex vivo and in vivo. The present study was designed to further characterize the stimuli that can activate recombinant eNOS enzyme expressed in the adventitia of cerebral arteries. To stimulate recombinant eNOS, we used serum (0. 1-10%), substance P (10(-11)-3 x 10(-9) M), and ANG II (10(-7)-10(-5) M) because they increase intracellular calcium concentrations in fibroblasts. Endothelium-denuded segments of canine basilar arteries were incubated with an adenoviral vector encoding beta-galactosidase gene or eNOS gene for 30 min at 37 degrees C. After 24 h, vasomotor activity and cGMP formation in eNOS or beta-galactosidase arteries were examined by isometric force recording and by radioimmunoassay, respectively. In control arteries and beta-galactosidase gene-transduced arteries, serum caused concentration-dependent contractions, whereas in recombinant eNOS gene-transduced arteries, serum produced concentration-dependent relaxations. Substance P and ANG II had no effect on vascular tone in control and beta-galactosidase arteries but caused concentration-dependent relaxations as well as a significant increase in cGMP levels in eNOS arteries. These relaxations were blocked by the NOS inhibitor NG-nitro-L-arginine methyl ester. Chemical treatment or mechanical inactivation of adventitial function significantly attenuated substance P-induced relaxations and ANG II-induced relaxations. These findings demonstrate that serum, substance P, and ANG II cause adventitia-dependent relaxations in cerebral arteries expressing the recombinant eNOS gene. This mechanism of vasodilatation may have beneficial effects in the prevention and treatment of vascular disorders characterized by the diminished bioavailability of NO, such as cerebral vasospasm.

Macrophage infiltration and heme oxygenase-1 expression correlate with angiogenesis in human gliomas

Macrophages are key participants in angiogenesis. In this study on human brain tumors, we first investigated whether macrophage infiltration is associated with angiogenesis and malignant histological appearance. Immunostaining of macrophages and small vessels in resected glioma specimens indicated that numbers of infiltrating macrophages and small vessel density were higher in glioblastomas than in astrocytomas or anaplastic astrocytomas. Macrophage infiltration was closely correlated with vascular density in human gliomas. Heme oxygenase-1 (HO-1), which is the rate-limiting enzyme in heme catabolism, was also associated with activated macrophages. Expression of mRNA encoding HO-1 was correlated with macrophage infiltration and vascular density in human glioma samples. Infiltrating macrophages were positively stained with anti-HO-1 antibody by immunohistochemical analysis, and in situ hybridization for HO-1 indicated that HO-1 was expressed in infiltrating macrophages in gliomas. HO-1 gene may be a useful marker for macrophage infiltration as well as neovascularization in human gliomas.

Expression and function of recombinant endothelial nitric oxide synthase gene in canine basilar artery after experimental subarachnoid hemorrhage

BACKGROUND AND PURPOSE

Gene transfer with recombinant viral vectors encoding vasodilator proteins may be useful in therapy of cerebral vasospasm after subarachnoid hemorrhage (SAH). Relaxations mediated by nitric oxide are impaired in cerebral arteries affected by SAH. The present study was designed to determine the effect of SAH on the efficiency of ex vivo adenovirus-mediated gene transfer to canine basilar arteries and to examine whether expression of recombinant endothelial nitric oxide synthase (eNOS) gene may have functional effects on vasomotor reactivity of spastic arteries affected by SAH.

METHODS

Replication-deficient recombinant adenovirus vectors encoding bovine eNOS (AdCMVeNOS) and Escherichia coli beta-galactosidase (AdCMVbeta-Gal) genes were used for ex vivo gene transfer. Rings of basilar arteries obtained from control dogs and dogs exposed to SAH were incubated with the vectors in minimum essential medium. Twenty-four hours after gene transfer, expression and function of the recombinant genes were evaluated by (1) histochemical or immunohistochemical staining, (2) beta-galactosidase protein measurement, and (3) isometric tension recording.

RESULTS

Transduction with AdCMVbeta-Gal and AdCMVeNOS resulted in the expression of recombinant beta-galactosidase and eNOS proteins mostly in the vascular adventitia. The expression of beta-galactosidase protein was approximately 2-fold higher in SAH arteries than in normal arteries. Endothelium-dependent relaxations caused by bradykinin and substance P were suppressed in SAH arteries. The relaxations to bradykinin were significantly augmented in both normal and SAH arteries after AdCMVeNOS transduction but not after AdCMVbeta-Gal transduction. The relaxations to substance P were augmented by AdCMVeNOS transduction only in normal arteries. Bradykinin and substance P caused relaxations even in endothelium-denuded arteries, when the vessels were transduced with AdCMVeNOS. These endothelium-independent (adventitia-dependent) relaxations to bradykinin observed after AdCMVeNOS transduction were similar between normal and SAH arteries, whereas those to substance P were significantly reduced in SAH arteries compared with normal arteries.

CONCLUSIONS

These results suggest that expression of recombinant proteins after adenovirus-mediated gene transfer may be enhanced in cerebral arteries affected by SAH and that successful eNOS gene transfer to spastic arteries can at least partly restore the impaired nitric oxide-mediated relaxations through local (adventitial) production of nitric oxide.

The effect of subarachnoid hemorrhage on mechanisms of vasodilation mediated by cyclic adenosine monophosphate

OBJECT

This study was designed to determine whether subarachnoid hemorrhage (SAH) affects the function of the K+ channels responsible for relaxation of canine cerebral arteries in response to adenylate cyclase activation.

METHOD

The effect of K+ channel inhibitors on the arterial relaxation response to forskolin, a direct adenylate cyclase activator, was studied in rings of basilar arteries obtained from normal dogs and dogs in which SAH was induced (double-hemorrhage model). The levels of adenosine 3',5'-cyclic monophosphate (cAMP) were measured using the radioimmunoassay technique. In rings with the endothelium removed, relaxation induced by forskolin was not affected by SAH. The relaxation response to forskolin was reduced by charybdotoxin (10(-7) mol/L), a selective Ca++-activated K+ channel inhibitor, in normal arteries and arteries subjected to autologous blood injection. This inhibitory effect of charybdotoxin was significantly greater in arteries involved in SAH than in normal vessels. The relaxation response to forskolin was reduced by 4-aminopyridine (10(-3) mol/L), a delayed rectifier K+ channel inhibitor, only in arteries involved in SAH. In contrast, the relaxation response to forskolin was not affected by glyburide (10(-5) mol/L), an adenosine 5'-triphosphate-sensitive K+ channel inhibitor, in both normal and SAH arteries. Forskolin (3 x 10(-7) mol/L) produced an approximately 10-fold increase in levels of cAMP. The basal values and increased levels of cAMP detected after stimulation with forskolin were no different in normal arteries and those exposed to SAH.

CONCLUSIONS

These results demonstrate that formation of cAMP and the relaxation response to adenylate cyclase activation are not affected by SAH. However, in diseased arteries, K+ channels assume a more important role in the mediation of relaxation response to forskolin, indicating that SAH may change the mechanisms responsible for vasodilation induced by cAMP.

Increase in calcium in smooth muscle cells of the rabbit bladder induced by acetylcholine and ATP

Cultured smooth muscle cells from rabbit urinary bladder were loaded with fura-2. Changes in intracellular Ca concentration [Ca2+]i produced by acetylcholine (ACh) or adenosine triphosphate (ATP) were estimated by measuring the fluorescence ratio F340/F380. Western blot analysis and immunohistochemical techniques showed that the cultured cells retained alpha-smooth muscle actin. ATP produced a rapid but transient increase in [Ca2+]i and ACh produced a delayed, prolonged increase. Application of ACh after ATP in Ca-free solution failed to elevate [Ca2+]i suggesting that both ACh and ATP release Ca2+ from the same intracellular stores. Following application of ACh but not ATP in Ca-free Krebs solution, reintroduction of Ca2+ produced elevation of [Ca2+]i, indicating that ACh causes prolonged opening of channels in the membrane. The sustained increase induced by ACh was abolished by nicardipine (blocker of Ca2+ voltage dependent channel ICa(V)) or quinine (blocker of non-selective cation channels). Although the elevations to ACh or ATP were abolished by neomycin (an inhibitor of phospholipase C) the different time courses suggest that the mechanisms of release of Ca2+ from intracellular stores or the pathway for refilling the stores is different.

The effect of 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ) and charybdotoxin (CTX) on relaxations of isolated cerebral arteries to nitric oxide

The mechanism underlying smooth muscle relaxations of cerebral arteries in response to nitric oxide is still not completely understood. The present study was designed to determine the role of soluble guanylate cyclase in the relaxations to a nitric oxide/nucleophile complex, diethylaminodiazen-1-ium-1,2-dioate (DEA-NONOate). Rings of canine middle cerebral arteries without endothelium were suspended in Krebs-Ringer bicarbonate solution for isometric tension recording. The levels of guanosine 3',5'-cyclic monophosphate (cyclic GMP) were measured by radioimmunoassay technique. During contractions to uridine 5'-triphosphate (UTP), DEA-NONOate (10(-10) to 10(-5) M) caused concentration-dependent relaxations. Measurements of cyclic GMP levels in cerebral arterial wall demonstrated that DEA-NONOate is a potent stimulator of guanylate cyclase and subsequent formation of cyclic GMP. Increasing concentrations of a selective soluble guanylate cyclase inhibitor, 1H-[1,2,4]-oxadiazolo[4,3-a]quinoxalin-1-one (ODQ), caused concentration-dependent reduction of both cyclic GMP production and relaxations to DEA-NONOate. Interestingly, in the presence of the highest concentration (3 x 10(-6) M) of ODQ, production of cyclic GMP in response to 10(-6) M of DEA-NONOate was abolished, whereas the same concentration of DEA-NONOate caused almost complete relaxation, suggesting that mechanisms independent of cyclic GMP production may mediate relaxing effect of high concentration of a nitric oxide donor. A selective Ca2+-activated potassium channel blocker charybdotoxin (CTX) significantly reduced relaxations to DEA-NONOate resistant to ODQ, supporting the idea that in cerebral arteries nitric oxide may activate potassium channels independently of cyclic GMP. The results of our study suggest that under physiological conditions, guanylate cyclase is a key mediator of cerebral arterial relaxations to nitric oxide. However, under pathological conditions associated with induction of nitric oxide synthase and increased biosynthesis of nitric oxide (e.g., cerebral ischemia, inflammation, sepsis), mechanisms other than formation of cyclic GMP may be activated.

Subarachnoid hemorrhage and the role of potassium channels in relaxations of canine basilar artery to nitrovasodilators

This study was designed to determine the effect of subarachnoid hemorrhage (SAH) on potassium (K+) channels involved in relaxations of cerebral arteries to nitrovasodilators. The effects of K+ channel inhibitors on relaxations to 3-morpholinosydnonimine (SIN-1) and sodium nitroprusside (SNP) were studied in rings of basilar arteries obtained from untreated dogs and dogs exposed to SAH. The levels of cyclic GMP were measured by radioimmunoassay. In rings without endothelium, concentration-dependent relaxations to SIN-1 (10(-9)-10(-4) mol/L) and SNP (10(-9)-10(-4) mol/L) were not affected by SAH, whereas increase in cyclic GMP production stimulated by SIN-1 (10(-6) mol/L) was significantly suppressed after SAH. The relaxations to SIN-1 and SNP were reduced by charybdotoxin (CTX: 10(-7) mol/L), a selective Ca(2+)-activated K+ channel inhibitor, in both normal and SAH arteries; however, the reduction of relaxations by CTX was significantly greater in SAH arteries. By contrast, the relaxations to these nitrovasodilators were not affected by glyburide (10(-5) mol/L), an ATP-sensitive K+ channel inhibitor, in both normal and SAH arteries. These findings suggest that in cerebral arteries exposed to SAH, CA(2+)-activated K+ channels may play a compensatory role in mediation of relaxations to nitric oxide. This may help to explain mechanisms of relaxations to nitrovasodilators in arteries with impaired production of cyclic GMP.

Heterogeneity of Ca2+ gating of skeletal muscle and cardiac ryanodine receptors

The single-channel activity of rabbit skeletal muscle ryanodine receptor (skeletal RyR) and dog cardiac RyR was studied as a function of cytosolic [Ca2+]. The studies reveal that for both skeletal and cardiac RyRs, heterogeneous populations of channels exist, rather than a uniform behavior. Skeletal muscle RyRs displayed two extremes of behavior: 1) low-activity RyRs (LA skeletal RyRs, approximately 35% of the channels) had very low open probability (Po < 0.1) at all [Ca2+] and remained closed in the presence of Mg2+ (2 mM) and ATP (1 mM); 2) high-activity RyRs (HA skeletal RyRs) had much higher activity and displayed further heterogeneity in their Po values at low [Ca2+] (< 50 nM), and in their patterns of activation by [Ca2+]. Hill coefficients for activation (nHa) varied from 0.8 to 5.2. Cardiac RyRs, in comparison, behaved more homogeneously. Most cardiac RyRs were closed at 100 nM [Ca2+] and activated in a cooperative manner (nHa ranged from 1.6 to 5.0), reaching a high Po (> 0.6) in the presence and absence of Mg2+ and ATP. Heart RyRs were much less sensitive (10x) to inhibition by [Ca2+] than skeletal RyRs. The differential heterogeneity of heart versus skeletal muscle RyRs may reflect the modulation required for calcium-induced calcium release versus depolarization-induced Ca2+ release.

Role of potassium channels in relaxations of canine middle cerebral arteries induced by nitric oxide donors

BACKGROUND AND PURPOSE

The mechanisms underlying smooth muscle relaxations of cerebral arteries in response to nitric oxide (NO) and cyclic GMP (cGMP) are still not completely understood. The present study was designed to determine the role of potassium channels in the relaxations to NO donors 3-morpholinosydnonimine (SIN-1) and sodium nitroprusside (SNP), as well as 8-bromo-3',5' -cGMP (a synthetic analogue of cGMP) and zaprinast (a selective cGMP phosphodiesterase inhibitor).

METHODS

Rings of canine middle cerebral asteries without endothelium were suspended in Krebs-Ringer bicarbonate solution for isometric tension recording. The levels of cGMP were measured by radioimmunoassay. Relaxations to NO donors 8-bromo-cGMP and zaprinast were studied in the presence and in the absence of K+ channel blockers charybdotoxin (large-conductance Ca(2+)-activated K+ channels), glyburide (ATP-sensitive K+ channels), 4-aminopyridine (delayed rectifier K+ channels), and BaCl2 (multiple types of K+ channels).

RESULTS

Concentration-dependent relaxations caused by NO donors (SIN-1 and SNP) were significantly reduced in arteries treated with BaCl2 (3 x 10(-4) mol/L) or charybdotoxin (3 x 10(-8) mol/L). Relaxations to 8-bromo-cGMP were not affected by the same concentrations of BaCl2 and charybdotoxin; however, they were reduced by higher concentrations of BaCl2 (3 x 10(-3) mol/L) or charybdotoxin (10(-7) mol/L). Zaprinast-induced relaxations were significantly reduced by BaCl2 (3 x 10(-4) mol/L) or charybdotoxin (3 x 10(-8) mol/L). Glyburide (10(-5) mol/L) and 4-aminopyridine (10(-3) mol/L) did not alter the relaxations to SIN-1 or SNP. The production of cGMP stimulated by SIN-1 in the vascular smooth muscle was not affected by BaCl2 (3 x 10(-3) mol/L) or charybdotoxin (10(-7) mol/L).

CONCLUSIONS

These results indicate that in canine middle cerebral arteries, a significant portion of relaxations to NO liberated from nitrovasodilators is mediated by large-conductance Ca(2+)-activated K+ channels. Other K+ channels, sensitive to BaCl2, may also be involved in the mechanism of relaxations induced by NO.

Identification of the cell type origin of odontoma-like cell masses in microphthalmic (mi/mi) mice by in situ hybridization

Tooth abnormalities occur in microphthalmic (mi/mi) mice. The elongated odontogenic epithelium is interrupted by unresorbed bone at the basal end of the mi/mi incisor, with the epithelium gathered into cell clusters. These clusters develop to odontoma-like masses. To identify the origin of the cell types of these odontoma-like masses, the localization of osteonectin (Osn), osteocalcin (Osc), osteopontin (Osp), matrix Gla protein (MGP) and amelogenin (Am) mRNA in the process of tooth development in mi/mi and +/+ mice was investigated by means of in situ hybridization. Decalcified mandibles of neonatal, 5-, 10-, 14-day-old mice were examined. Osn and Osc mRNA, which localized in osteoblasts and odontoblasts, were also detected in the cells of odontoma-like masses in mi/mi mice. The cells expressing these mRNA were short, columnar and odontoblast-like. Am mRNA was detected in ameloblasts. In mi/mi mice, Am mRNA was also detected in ameloblastic cell clusters, which were formed by the tall columnar cells in the odontoma-like masses. No apparent Osp mRNA expression was detected in the masses. These results indicated that even in odontogenic abnormal cells resulting from physical obstruction in mi/mi mice, the genes that are involved in normal tooth development were still expressed.

Selective binding of FKBP12.6 by the cardiac ryanodine receptor

The calcium release channels (CRC)/ryanodine receptors of skeletal (Sk) and cardiac (C) muscle sarcoplasmic reticulum (SR) are hetero-oligomeric complexes with the structural formulas (ryanodine recepter (RyR)1 protomer)4(FKBP12)4 and (RyR2 protomer)4(FKBP12.6)4, respectively, where FKBP12 and FKBP12.6 are isoforms of the 12-kDa receptor for the immunosuppressant drug FK506. The sequence similarity between the RyR protomers and FKBP12 isoforms is 63 and 85%, respectively. Using 35S-labeled FKBP12 and 35S-labeled FKBP12.6 as probes to study the interaction with CRC, we find that: 1) analogous to its action in skeletal muscle sarcoplasmic reticulum (SkMSR), FK506 (or analog FK590) dissociates FKBP12.6 from CSR; 2) both FKBP isoforms bind to FKBP-stripped SkMSR and exchange with endogenously bound FKBP12 of SkMSR; and 3) by contrast, only FKBP12. 6 exchanges with endogenously bound FKBP12.6 or rebinds to FKBP-stripped CSR. This selective binding appears to explain why the cardiac CRC is isolated as a complex with FKBP12.6, whereas the skeletal muscle CRC is isolated as a complex with FKBP12, although only FKBP12 is detectable in the myoplasm of both muscle types. Also, in contrast to the activation of the channel by removal of FKBP from skeletal muscle, no activation is detected in CRC activity in FKBP-stripped CSR. This differential action of FKBP may reflect a fundamental difference in the modulation of excitation-contraction coupling in heart versus skeletal muscle.

Localization and expression of phospholipases A2 in Trimeresurus flavoviridis (habu snake) venom gland

The localization and expression profiles of phospholipases A2 (PLA2s) in Trimeresurus flavoviridis venom gland were studied by means of in situ hybridization and immunohistochemical techniques. Venom gland cells are tightly arrayed in a single layer along the inlet-like lumens in which venom proteins are stored. mRNAs for PLA2s were detected at the high level in cytoplasm. Using the immunohistochemical technique with polyclonal anti-Asp-49-PLA2 antibody, Asp-49-PLA2 and, possibly, its isozymes were detected in intracellular granules and in venom lumens. The intracellular granules containing PLA2 proteins appear to be transferred from the nucleus towards the outer membrane facing the lumen, and then to be secreted.

Affinity purification of the ryanodine receptor/calcium release channel from fast twitch skeletal muscle based on its tight association with FKBP12

The ryanodine receptor (RyR)/calcium release channel isolated from skeletal muscle terminal cisternae (TC) of sarcoplasmic reticulum (SR) is tightly associated with FK506 binding protein of 12.0 kDa (FKBP12) (Jayaraman et al., (1992) J.Biol.Chem. 267, 9474-9477). In this study, we describe a new method of affinity chromatography for purifying the RyR from skeletal muscle SR based on: 1) its tight association with FKBP12; and 2) the finding that bound FKBP on the RyR can be exchanged with soluble FKBP12 (Timerman et al., (1995) J.Biol.Chem. 270, 2451-2459). Soluble glutathione S-transferase/FKBP12 (GST/FKBP12) fusion protein was first exchanged with bound FKBP12 on the RyR of TC. The TC were then solubilized with CHAPS and the complex of RyR.GST/FKBP12 was specifically adsorbed by glutathione Sepharose 4B and then eluted with glutathione. The RyR, purified by this method, has similar characteristics by SDS-PAGE, radioligand binding and immuno-reactivity as the RyR purified by multiple sequential column chromatography.

Altered reactivity of human cerebral arteries after subarachnoid hemorrhage

To investigate the effects of subarachnoid hemorrhage (SAH) on the responsiveness of human cerebral arteries to vasoactive substances, the authors measured the isometric tension generated in helical strips of basilar and middle cerebral arteries isolated from human cadavers. Contractions caused by KCl, prostaglandin F2 alpha, noradrenaline, and serotonin were reduced in arteries obtained from cadavers with aneurysmal SAH damage and compared to those obtained from cadavers with no indication of intracranial diseases. Endothelium-dependent relaxation elicited by substance P and bradykinin, and endothelium-independent relaxation induced by prostaglandin I2 and nitroglycerin were also markedly decreased in arteries affected by SAH. However, the reduction in relaxation response to prostaglandin I2 was significantly less than that to the other vasodilator agents. These results indicate that human cerebral artery functions are severely impaired after SAH and that poor responses to vasoactive agents may result primarily from dysfunction of smooth-muscle cells.

Brain histaminergic system in mast cell-deficient (Ws/Ws) rats: histamine content, histidine decarboxylase activity, and effects of (S) alpha-fluoromethylhistidine

The mast cell-deficient [Ws/Ws (White spotting in the skin)] rat was investigated with regard to the origin of histamine in the brain. No mast cells were detected in the pia mater and the perivascular region of the thalamus of Ws/Ws rats by Alcian Blue staining. The histamine contents and histidine decarboxylase (HDC) activities of various brain regions of Ws/Ws rats were similar to those of +/+ rats except the histamine contents of the cerebral cortex and cerebellum. As the cerebral cortex and cerebellum have meninges that are difficult to remove completely, the histamine contents of these two regions may be different between Ws/Ws and +/+ rats. We assume that the histamine content of whole brain with meninges in Ws/Ws rats is < 60% of that in +/+ rats. So we conclude that approximately half of the histamine content of rat brain is derived from mast cells. Next, the effects of (S) alpha-fluoromethylhistidine (FMH), a specific inhibitor of HDC, on the histamine contents and HDC activities of various regions of the brain were examined in Ws/Ws rats. In the whole brain of Ws/Ws rats, 51 and 37% of the histamine content of the control group remained 2 and 6 h, respectively, after FMH administration (100 mg/kg of body weight). Therefore, we suggest that there might be other histamine pools including histaminergic neurons in rat brain.

Phosphorylation modulates the function of the calcium release channel of sarcoplasmic reticulum from cardiac muscle

The cardiac calcium release channel (CRC) of sarcoplasmic reticulum vesicles was incorporated into planar lipid membranes to evaluate modulation of channel activity by phosphorylation and dephosphorylation. For this purpose a microsyringe application directly to the membrane was used to achieve sequential and multiple treatments of channels with highly purified kinases and phosphatases. Cyclic application of protein kinase A (PKA) or Ca2+/calmodulin-dependent protein kinase II (CalPK) and potato acid phosphatase or protein phosphatase 1 revealed a channel block by Mg2+ (-mM), that is referable to dephosphorylated states of the channel, and that the Mg2+ block could be removed by phosphorylation of the CRC by either PKA or CalPK. By contrast, activation of endogenous CalPK (end CalPK) led to channel closure which could be reversed by dephosphorylation using potato acid phosphatase or protein phosphatase 1. Calmodulin by itself (which activates end CalPK in the presence of MgATP) blocks the channel in the dephosphorylated state, which can be overcome by treatment with CalPK but not PKA. Our findings reveal important insights regarding channel regulation of the ryanodine receptor: 1) the calcium release channel must be phosphorylated to be in the active state at conditions approximating physiological Mg2+ concentrations (-mM); and 2) there are multiple sites of phosphorylation on the calcium release channel with different functional consequences, which may be relevant to the regulation of E-C coupling. Phosphorylation of the CRC may be involved in recruitment of active channels, and/or it may be directly involved in each Ca2+ contraction cycle of the heart. For example, Ca2+ release may require phosphorylation of the CRC by protein kinases at sites which overcome the block by Mg2+. Inactivation may involve CRC block by calmodulin and/or phosphorylation by endogenous CalPK at the junctional face membrane.

Identification of the cells expressing cot proto-oncogene mRNA

The cell types expressing cot proto-oncogene mRNA were identified by in situ hybridization (ISH) histochemistry. Among a variety of adult mouse tissues examined, four types of glandular cells expressing cot gene were identified: (1) granular duct cells in the submandibular and sublingual glands; (2) serous cells in the parotid gland; (3) peptic (chief) cells in gastric glands; and (4) goblet cells in colonic glands. Investigation of the developmentally regulated expression of cot mRNA using tissues of 14-day and 18-day embryos, newborn and weanling mice showed that cot gene is expressed only in morphologically differentiated and functionally activated cells of these four types. No other types of cells showing ISH signals were observed. Based on these results, cot gene expressions in cultured cells of colonic adenocarcinomas and gastric adenocarcinomas were examined. SW 480 and WiDr cells showed high expression of this gene and so should be useful for functional analysis of Cot kinase. The expression patterns of cot gene in tumor tissues of the parotid gland, and gastric and colonic glands were investigated. Two of the tissues overexpressed this gene markedly, suggesting that overproduction of Cot kinase may be one cause of their transformation.

Suppression of cerebral vasodilation with endothelin-1

We investigated the effect of endothelin-1 on relaxation responses induced by vasodilator substances in canine middle cerebral arteries to better understand regulation of cerebrovascular tone and its potential impact on mechanism of cerebral vasospasm. Endothelin-1 elicited concentration-dependent contractions in helical strips of canine cerebral arteries (EC50; 4.62 x 10(-9) M). Pretreatment with 10(-9) M endothelin-1 significantly reduced endothelium-dependent relaxation elicited by substance P and endothelium-independent relaxations by nitroglycerin, prostaglandin I2, and KCl. Although endothelin-1 in a lower concentration (10(-10) M) did not affect these endothelium-independent relaxations, it did inhibit endothelium-dependent relaxation caused by substance P. A low concentration (10(-10) M) of endothelin-1 also significantly reduced endothelium-dependent relaxation of canine mesenteric arteries induced by acetylcholine. Other vasoconstrictor peptides such as angiotensin-II and vasopressin did not inhibit endothelium-dependent and -independent relaxations. These results indicate that endothelin-1 not only produces cerebral vasoconstriction but also interferes with vasodilator mechanisms and that endothelium-dependent vasodilation is more sensitive to the inhibitory effect of endothelin-1 than endothelium-independent vasodiltion.

Human basilar and middle cerebral arteries exhibit endothelium-dependent responses to peptides

We examined the activities of bradykinin, substance P, and vasopressin in isolated human cerebral arteries to better understand humoral control of cerebrovascular tone. Basilar and middle cerebral arteries were isolated from human cadavers during autopsy, and isometric tension was measured in helical strips of the arteries. Both bradykinin and substance P relaxed strips of both arteries precontracted with prostaglandin F2 alpha to similar extents. The relaxations induced by both peptides were abolished by removal of the vascular endothelium and were markedly reduced by pretreatment with NG-nitro-L-arginine, an inhibitor of endothelium-derived relaxing factor. Treatment with indomethacin, a cyclooxygenase inhibitor, did not attenuate the relaxations. These results indicate that the responses of human cerebral arteries to bradykinin and substance P are mediated by endothelium-derived relaxing factor. In contrast, vasopressin primarily produced endothelium-independent contractions in human cerebral arteries. Contractions of basilar arteries induced by vasopressin were much less than those of middle cerebral arteries. Two of eighteen basilar arteries, but none of the middle cerebral arteries, responded to vasopressin with endothelium-dependent relaxation. This suggests that the function of vasopressin receptors differs in basilar and middle cerebral arteries.

Alterations in the expression of osteonectin, osteopontin and osteocalcin mRNAs during the development of skeletal tissues in vivo

Heterogeneity in the expression of three members of non-collagenous matrix proteins in osteogenic and chondrogenic development in vivo were investigated by in situ hybridization. Sections of several skeletal tissues from mice at various stages of development were hybridized with digoxigenin-labeled complementary RNA probes encoding osteonectin (Osn), osteopontin (Osp) and osteocalcin (Osc). In calvariae and mandibulae, Osn messenger RNA (mRNA) was detected in cells in pre-osseous and osseous tissues before mineralization. Osp mRNA was found in cells attached to the mineralized bone matrix together with Osn mRNA followed by the expression Osc mRNA. In long bones, mRNAs for Osn, Osp and Osc were sequentially expressed with bone development from primary spongiosa to diaphyseal bone. In growth cartilage, Osn mRNA was observed in chondrocytes in non-mineralized cartilage, whereas Osp mRNA was detected in hypertrophic chondrocytes in mineralized cartilage matrix with a characteristic switch in expression. Osc mRNA was not detected in any chondrocytes. These results indicate that osteogenic differentiation in bone development in vivo is characterized by the sequential expression of these three genes, and suggest that these genes are expressed differentially and specifically, in association with extra-cellular matrix mineralization.

C-kit gene is expressed by skin mast cells in embryos but not in puppies of Wsh/Wsh mice: age-dependent abolishment of c-kit gene expression

The Wsh is a mutant allele at the W (c-kit) locus of mice, but no significant abnormalities are found at the coding region of the Wsh allele. Since cultured mast cells derived from the spleen of Wsh/Wsh mice do not express messenger RNA (mRNA) of c-kit, we studied the interrelation between the number of mast cells and the magnitude of c-kit mRNA expression in the skin of Wsh/Wsh mice of various ages. The number of mast cells in the skin of Wsh/Wsh embryos of 18 days postcoitum (pc) was approximately 40% that of normal control (+/+) embryos, but the number of mast cells decreased exponentially after birth; the number dropped to 0.6% that of +/+ mice at day 150 after birth. A weak but apparent signal of c-kit mRNA was detectable in the skin of 18-day pc Wsh/Wsh embryos by RNase protection assay but not in the skin of 5-day-old Wsh/Wsh mice. The number of c-kit protein-containing cells was significantly greater in the skin of 18-day pc Wsh/Wsh embryos than in the skin of 5-day-old Wsh/Wsh mice. The abolishment of c-kit mRNA expression appeared to be specific, because the expression of mast cell carboxypeptidase A mRNA but not of c-kit mRNA was detectable by in situ hybridization in skin mast cells of 5-day-old Wsh/Wsh mice. Taken together, the expression of c-kit mRNA was abolished first, then the content of c-kit protein dropped to undetectable levels, and then the disappearance of Wsh/Wsh mast cells themselves followed.

Expression of neurotrophin genes in the brain of senescence-accelerated mouse (SAM) during postnatal development

We compared the expression patterns of neurotrophin genes in the brain of senescence-accelerated mouse (SAMP8) which shows age-related impairment of learning behavior, with SAMR1 control which shows normal aging. By Northern blot analysis, NT-3 mRNA levels in the cortex were higher in SAMP8 than in SAMR1 mice during development, whereas in the midbrain, hippocampus and forebrain, NT-3 expression levels in SAMP8 were lower than those in SAMR1. At early stages, although NGF mRNA levels in SAMP8 were lower than those in SAMR1, BDNF mRNA levels were almost equivalent in both strains. By in situ hybridization analysis, NT-3 mRNA signals in the CA1 and CA2 regions in SAMP8 were shown to be reduced at early stages. However, BDNF mRNA signals were almost equivalent in both SAMR1 and SAMP8.

The ryanodine receptor from canine heart sarcoplasmic reticulum is associated with a novel FK-506 binding protein

We find that the purified ryanodine receptor/calcium release channel (CRC) isolated from canine heart sarcoplasmic reticulum (SR) is tightly associated with an FK-506 binding protein which is distinct from human recombinant FKBP-12. Fractions from both skeletal and heart muscle were probed by Western Blot analysis using sequence specific antibody raised against the N-terminus of human recombinant FKBP-12. Only FKBP-12 was detected in rabbit and dog skeletal muscle SR as well as in dog heart cytosol. Canine heart SR and the purified canine heart ryanodine receptor contained an immunoreactive band with a somewhat slower relative mobility than that of human recombinant FKBP-12. These observations indicate that the association between the cardiac CRC and this novel FK-506 binding protein is specific.

PKC gamma gene expression is delayed in postnatal central nervous system of mi/mi mice

In the central nervous system (CNS), the expression of protein kinase C (PKC) genes is strictly controlled by the developmental stage. We have examined the expression of PKC genes (cPKC alpha, beta, gamma, and nPKC delta, epsilon) in the process of the postnatal development in normal (+/+) C57BL/6 and microphthalmic (mi/mi) C57BL/6 mouse brains by Northern blotting and in situ hybridization. By Northern blotting, the expression level of cPKC gamma mRNA in mi/mi mice was significantly lower than that in +/+ littermates at d 9, 13, and 17. By in situ hybridization analysis, cPKC gamma mRNA-positive cells were detected in hippocampal and Purkinje cells in +/+ and mi/mi mice, but the magnitude of the signals in mi/mi mice was lower than that of +/+ mice, and the number of positive cells was smaller, whereas other isozymes (cPKC alpha, beta, and nPKC delta, epsilon) showed no significant difference between normal and mi/mi mice. The neuronal morphometric analysis by anti-P400 antibody revealed the same number and expression level of P400 protein in cerebellar Purkinje cells compared with +/+ mice. These results indicate that the deficiency of mi gene product causes the delayed expression of the cPKC gamma gene.

Transcallosal interforniceal approach for a posteriorly projecting high basilar bifurcation aneurysm. Case report

A transcallosal interforniceal approach was used for treatment of a posteriorly projecting high basilar bifurcation aneurysm with a neck located 30 mm above the posterior clinoid process. The aneurysm was successfully clipped via the third ventricle with minimal neurological deficits. This approach appears to be appropriate for basilar bifurcation aneurysms located more than 20 mm above the posterior clinoid process when the fundus projects posteriorly, and permits direct visualization of the aneurysmal neck and vital perforators with minimal brain retraction.

Infection of Nippostrongylus brasiliensis induces normal increase of basophils in mast cell-deficient Ws/Ws rats with a small deletion at the kinase domain of c-kit

All basophils, mucosal-type mast cells (MMC) and connective tissue-type mast cells (CTMC) are derived from the multipotential hematopoietic stem cell. Mutations at the c-kit locus resulted in deficiency of MMC and CTMC in both mice and rats. To investigate the role of the c-kit receptor tyrosine kinase for production of basophils, we used white spotting/white spotting (Ws/Ws) mutant rats that have a small deletion at the tyrosine kinase domain of the c-kit gene. When Ws/Ws, nude athymic, and normal (+/+) rats were infected with Nippostrongylus brasiliensis (NB), the number of basophils increased greater than 50-fold in the peripheral blood of Ws/Ws and +/+ rats but did not increase in that of nude rats. Blood histamine concentration increased significantly in Ws/Ws and +/+ rats but did not increase in nude rats. Immature basophils increased greater than 10-fold in the bone marrow of Ws/Ws and +/+ rats but did not increase in that of nude rats. Mature and immature basophils that developed after the NB infection were identified by electron microscopy. The present result confirms that T-cell-derived cytokines are indispensable for the augmented production of basophils and suggests that stimulation via the c-kit receptor may not be necessary for the augmented production.

Expression and localization of oxytocin receptor gene in human uterine endometrium in relation to the menstrual cycle

The expression of oxytocin receptor mRNA in the human uterus was investigated by polymerase chain reaction after mRNA reverse transcription; in addition, the mRNA was localized by means of in situ hybridization histochemistry. Strong positive signals were observed in myometrial cells at parturition. In nonpregnant human uterine endometrium, oxytocin receptor mRNA was expressed in glandular epithelial cells, but was not observed in stromal cells. The signal in the epithelial cells was stronger at the time of ovulation than during any other phase. The sequential changes in oxytocin receptor mRNA expression in nonpregnant endometrium suggest some alternative biological function of oxytocin in endometrium during the menstrual cycle.

Absence of immature mast cells in the skin of Ws/Ws rats with a small deletion at tyrosine kinase domain of the c-kit gene

Ws/Ws rats have a small deletion at the tyrosine kinase domain of the c-kit gene, and practically no mast cells were detectable when the tissues were stained with alcian blue. Because alcian blue stains proteoglycans, there is a possibility that immature mast cells that do not contain a sufficient amount of proteoglycans are not detectable by this method. We examined this possibility by using other markers of mast cells. The histamine content in the skin of Ws/Ws rats was 0.3% that of control normal (+/+) rats. Because the number of alcian blue-positive mast cells in the skin of Ws/Ws rats was also 0.3% that of +/+ rats, histamine in the skin seemed to be concentrated to alcian blue-positive mast cells. Mast cells in the skin of +/+ rats express messenger RNA of Fc epsilon RI beta-subunit and c-kit protein. Because c-kit messenger RNA was normally expressed at least in the brain of Ws/Ws rats despite the small deletion, we examined the expression of Fc epsilon RI beta-subunit and c-kit messenger RNA in the skin and stomach of Ws/Ws rats by reverse transcriptase modification of polymerase chain reaction. Expression of either Fc epsilon RI beta-subunit or c-kit messenger RNA in the skin and stomach of Ws/Ws rats was estimated to be less than 1% that of +/+ rats. Moreover no Fc epsilon RI beta-subunit-expressing and no c-kit-expressing cells were detectable in the skin of Ws/Ws rats by in situ hybridization histochemistry. The present result suggests the absence of immature mast cells in tissues of Ws/Ws rats.

Investigation of postmortem functional changes in human cerebral arteries

This study demonstrated the time-dependent changes in postmortem responses of isolated human middle cerebral artery strips to vasodilators. The relaxation induced by prostaglandin (PG) I2 or nitroglycerin remained stable for 24 h postmortem. In arterial strips precontracted with PGF2 alpha, substance P and bradykinin both elicited relaxation that was almost completely abolished by removal of the endothelium. The endothelium-dependent response to both peptides was significantly degraded in strips obtained > 12 h postmortem. These results indicate a selective functional or anatomical vulnerability of the vascular endothelium compared with that of the vasodilator mechanisms of the smooth muscle in the postmortem period. However, cerebral arteries isolated from human cadavers within 12 h postmortem should be adequate for studies of both smooth muscle and endothelial reactivity to vasodilators.