Cloning, functional expression and tissue distribution of rabbit alpha1a-adrenoceptor

A cDNA clone, which has an open reading frame of 1398 nucleotides encoding a 466-amino-acid peptide, has been isolated from rabbit liver cDNA library. Compared with the peptide sequence, it shows high homology to alpha1a adrenoceptors of human, bovine and rat. We expressed this clone in COS-7 and investigated the pharmacological properties, revealing similarity to those of human alpha1a adrenoceptors. Competitive RT/PCR has detected the mRNA in variety of rabbit tissues, especially abundantly in liver, vas deferens, brain, and aorta, but not in heart.

[Changes in the extent of mitral regurgitation during hemodialysis: color Doppler echocardiographic study]

The changes in the extent of mitral regurgitation (MR) during maintenance hemodialysis patients were studied in six patients with MR by color Doppler echocardiography. M-mode, two-dimensional and color Doppler echocardiography were performed before and every hour during hemodialysis. The severity of MR was evaluated by a semiquantitative grading system and maximal MR area. Hemodialysis removed 2.1 +/- 0.9/body fluid. Blood pressure and heart rate did not change systematically by hemodialysis. Left atrial, left ventricular end-diastolic and end-systolic dimensions were significantly decreased by hemodialysis (p < 0.05). Stroke volume and left ventricular wall stress were also significantly decreased (p < 0.01). MR area was significantly smaller at the end of hemodialysis compared to pre-hemodialysis (49.0 +/- 20.5 vs 171.0 +/- 49.2 mm2, p < 0.05). During hemodialysis, the extent of MR was continuously decreased. In two out of six patients, the MR jet disappeared. The extent of MR may depend on the fluid volume removed by hemodialysis because the MR area diminished more as more fluid was removed. No major disorders of the mitral complex were detected when the MR area was decreased rapidly to less than 60 mm2 in response to the removal of a small amount of fluid. The dry weight should be determined as the body weight when MR is as small as possible by color Doppler echocardiography.

Interleukin-2 (IL-2) upregulates BAG-1 gene expression through serine-rich region within IL-2 receptor beta c chain

BAG-1 is a Bci-2-binding protein which functions in protection from apoptotic cell death. Here we provide evidence for interleukin-2 (IL-2)-mediated upregulation of BAG-1 expression. In hematopoietic cell line BAF-B03 F7 cells, gene transfer mediated expression of the IL-2R beta c chain is sufficient to confer proliferation and cell survival responses to IL-2. In these IL-2R beta c-expressing cells, BAG-1 mRNA was dramatically induced by IL-2. The IL-2-mediated induction of BAG-1 expression required the activation of tyrosine kinase(s) and was sensitive to rapamycin as the induction of bcl-2 expression was. Analysis of the transfectants which express mutant IL-2R beta c chains or mutant Janus family protein tyrosine kinase Jak3 lacking the kinase domain showed that the IL-2-mediated BAG-1 gene expression required the serinerich region within the IL-2R beta c chain, but Jak3 activation was dispensable. The signaling pathway for BAG-1 gene expression thus highly resembles that for bcl-2 gene expression, strongly suggesting that their induction shares the same signaling pathway. In addition, deletion of the serine-rich region led to loss of IL-2-mediated protection from apoptotic cell death. Taken together, these studies demonstrate that the serine-rich region of the IL-2R beta c chain mediates the coordinated expression of bcl-2 and BAG-1 genes, thereby contributing to suppression of apoptosis.

Ocular hypotensive mechanism of intravitreally injected brain natriuretic peptide in rabbit

PURPOSE

To determine whether brain natriuretic peptide (BNP) affects intraocular pressure (IOP), aqueous humor dynamics, and cyclic guanosine monophosphate (cGMP) concentration in the aqueous humor of the rabbit eye.

METHODS

Twenty microliters of 10(-4) M and 10(-5) M (2 nmol, 0.2 nmol) BNP or atrial natriuretic peptide (ANP) were injected intravitreally into rabbit eyes, after which the IOP was measured using a pneumatonometer. Aqueous humor dynamics were studied at approximately 6 hours after the intravitreal injection of 2 nmol BNP. Aqueous humor flow was measured by fluorophotometry, and outflow facility was measured by the two-level constant pressure perfusion method, whereas uveoscleral outflow was measured by the fluorescein isothiocyanate-dextran perfusion method. The concentration of cGMP in the aqueous humor at 6 hours after injection of 2 or 0.2 nmol BNP also was measured by enzyme immunoassay.

RESULTS

Intravitreal administration of BNP or of ANP caused a decrease in IOP, with a maximum effect at approximately 6 hours after the injection. Total outflow facility in eyes treated with 2 nmol BNP increased by 29%, although the aqueous humor flow and uveoscleral outflow did not show significant changes. The concentration of cGMP in the aqueous humor increased significantly in BNP-treated eyes.

CONCLUSIONS

Intravitreal injection of BNP into rabbit eyes reduced IOP because of an increase in the outflow facility. Brain natriuretic peptide also increased the concentration of cGMP in the aqueous humor. It is probable that BNP-activated guanylate cyclase induced an upregulation of cGMP in the aqueous humor.

Mechanism of resistance to NO-induced neurotoxicity in cultured rat dopaminergic neurons

We previously reported that mesencephalic dopaminergic neurons are resistant to cytotoxicity induced by nitric oxide (NO). This study investigated the intracellular mechanism that protects dopaminergic neurons against NO toxicity in rat mesencephalic cultures. Peroxynitrite anion, an active metabolite of NO, caused significant cytotoxic effects against dopaminergic and nondopaminergic neurons, but NO caused cytotoxic effects restricted to nondopaminergic neurons. In addition, we studied the effects of ascorbate, an anti-oxidant, on NO-induced neurotoxicity against dopaminergic neurons and found that coadministration of ascorbate failed to affect resistance against NO-induced neurotoxicity. These findings suggest that the protecting mechanism from NO neurotoxicity in dopaminergic neurons is based on inhibition of conversion of NO to peroxynitrite anion, is independent of the NO redox state, and is possibly due to suppression of superoxide anion production. Furthermore, we investigated NO-induced neurotoxicity with or without pretreatment with sublethal doses of methylphenylpyridium ion (MPP+). Following pretreatment with 1 microM MPP+, which did not show significant cytotoxic effects against dopaminergic neurons, NO demonstrated significant cytotoxicity. Therefore, MPP+ may inhibit the protecting systems from NO neurotoxicity in dopaminergic neurons.

Regulation of IFN-alpha/beta genes: evidence for a dual function of the transcription factor complex ISGF3 in the production and action of IFN-alpha/beta

BACKGROUND

Efficient production of interferons (IFNs) in virally infected cells is an essential aspect of the host defence. The transcription factor complex ISGF3 (IFN-stimulated gene factor 3) was originally identified as a critical mediator of the IFN signal; it is formed upon IFN receptor (IFNR) stimulation and binds to ISREs (IFN-stimulated response elements) to activate IFN-inducible genes. It has recently been shown that the DNA binding component of ISGF3, p48 (ISGF3gamma) also binds to virus-inducible elements in the IFN-alpha/beta genes, suggesting a potential new role of p48 in IFN production.

RESULTS

Primary cells from mice with a targeted disruption of the p48 gene show severe defects in virus-induced IFN-alpha/beta gene expression. A similar defect was also observed in cells lacking type I IFNR or Stat1, further demonstrating the role of IFN signalling in the induction of these IFN genes. ISGF3 in fact binds to the virus-inducible elements within the IFN-alpha/beta promoters. We also provide evidence showing that these elements are additionally controlled by an unidentified factor(s) which presumably triggers the primary phase of IFN gene induction.

CONCLUSIONS

Our results demonstrate that the IFN signal transducing complex ISGF3 plays a crucial role in IFN production and suggest that ISGF3 may participate directly in the activation of IFN-alpha/beta promoters. This dual function of ISGF3 may insure the efficient operation of this cytokine system in the host defence.

In vivo induction of inducible nitric oxide synthase by microinjection with interferon-gamma and lipopolysaccharide in rat hippocampus

To clarify whether the inducible nitric oxide synthase (iNOS) protein can be induced in in vivo brain, we examined the influence of direct intrahippocampal injection with interferon-gamma (IFN-gamma) plus lipopolysaccharide (LPS) in the rat. In the area surrounding the microinjection site, NOS activity (NO2- accumulation) was enhanced 24 h after injection with IFN-gamma plus LPS. Although the level of 160-kDa nNOS protein was not changed, the 130-kDa iNOS protein was induced 12 h after the injection. On the other hand, iNOS mRNA could be detected at 6 and 12 h but not at 24 h. iNOS immunoreactivity was observed in CD11b-immunopositive microglia in close proximity to the injection site, but the immunoreactivity was not colocalized with glial fibrillary acidic protein-immunopositive astrocytes. Although CD11b-immunopositive microglia were of the ramified type even after injection with vehicle after 24 h, injection with IFN-gamma plus LPS caused numerous microglia to change to the ameboid type and to express major histocompatibility complex (MHC) class II antigens. In some of these ameboidal microglia, iNOS immunoreactivity was observed. These results suggest that intrahippocampal injection with IFN-gamma plus LPS induced iNOS mRNA after 6 h and iNOS protein after 12 h in some of the ameboidal microglia that expressed MHC class II antigens in in vivo rat brain.

Autocrine loop through cholecystokinin-B/gastrin receptors involved in growth of human leukemia cells

The cholecystokinin (CCK)-B/gastrin receptor binds two brain-gut hormones, CCK and gastrin, with high affinities. These peptides have a trophic effect on gastrointestinal cells expressing the receptor in vivo as well as in vitro. Recently, this receptor mRNA was reported to be expressed in immunocytes localized in the lamina propria of normal rat stomach mucosa. Here, we studied the receptor expression in human hematopoietic cells in order to determine whether they play a role in cell growth. The CCK-B/gastrin receptor mRNA was detectable in the polymorphonuclear (PMN) cells but not in the mononuclear cells of normal peripheral white blood cells by reverse transcription-polymerase chain reaction. The receptor transcript was, however, expressed in human leukemia cell lines (14 of 18 cell lines tested) derived from not only myeloid, but also T- and B- lymphoid lineages. The CCK-B/gastrin receptors on several leukemia cell lines were shown to be biologically active by demonstrating ligand-dependent cell proliferation in serum-deprived medium. Interestingly, a human CCK-B/gastrin receptor specific antagonist, YM022, but not its stereotype isoform, selectively inhibited the DNA synthesis of THP-1, MOLT-16, MOLT-14, and CCRF-CEM in the absence of exogenous peptide ligands. Further investigation revealed that these leukemia cell lines and normal PMN cells also expressed gastrin mRNA. These results suggest that growth of human leukemia cells is promoted by an autocrine mechanism through the CCK-B/gastrin receptors.

ONO-1078 antagonizes diarrhea-causing changes in ion transport and smooth muscle contraction induced by peptidoleukotrienes in rat and human colon in vitro

Leukotrienes play important roles in inflammatory bowel diseases. Previous studies have revealed the effects of peptidoleukotrienes on smooth muscle contraction and transmucosal ion transport, which may cause hyperactive bowel movement and the loss of electrolytes and water, i.e., diarrhea. The purpose of the present study was to evaluate the effects of the peptidoleukotrienes antagonist ONO-1078 and to assess its possible future clinical use. We examined the effects of ONO-1078 on peptidoleukotrienes-induced changes in electrolyte transport and muscle contraction in the rat colon, with the Ussing and Magnus techniques. Human biopsy specimens obtained at colonoscopy were also used for ion transport studies. Transmucosal ion transport in both rats and humans, and smooth muscle contractions in the rat colon, were induced by similar doses of peptidoleukotrienes at estimated interstitial concentrations (1 nM-100 nM). The time course of changes in short circuit current had two phases, a rapid and transient decrease and a subsequent transient increase, which seemed to be due mainly to Na+ and Cl-, respectively. Rat colon smooth muscle contracted transiently after the addition of peptidoleukotrienes. These effects of peptidoleukotrienes, which could be related to the diarrhea in inflammatory bowel diseases, were inhibited by ONO-1078. ONO-1078 is expected to be effective in clinical use against peptidoleukotrienes-related diarrhea in mild to moderate inflammatory bowel diseases.

Cooperation of the tumour suppressors IRF-1 and p53 in response to DNA damage

Normally growing cells promptly cease DNA synthesis when exposed to genotoxic stresses, such as radiation, and this cell-cycle arrest prevents the accumulation of mutations. The transcription factor interferon regulatory factor (IRF)-1 is essential for the regulation of the interferon system, inhibits cell growth, and manifests tumour-suppressor activities. Here we show that mouse embryonic fibroblasts (EFs) lacking IRF-1 are deficient in their ability to undergo DNA-damage-induced cell-cycle arrest. A similar phenotype has been observed in EFs lacking the tumour suppressor p53 (refs 8, 9), although the expression of IRF-1 and p53 are independent of one another. Furthermore, we show that transcriptional induction of the gene encoding p21 (WAF1, CIP1), a cell-cycle inhibitor, by gamma-irradiation is dependent on both p53 and IRF-1, and that the p21 promoter is activated, either directly or indirectly, by both in a transient cotransfection assay. These two tumour-suppressor transcription factors therefore converge functionally to regulate the cell cycle through the activation of a common target gene.

[Surgical treatment of pericostal tuberculosis]

The following two points must be considered on treating pericostal tuberculosis: the first is the appropriate time to treat pericostal tuberculosis surgically when the medical therapy fails to induce a remission, and the second is how to prevent postoperative relapse. In the present study, we investigated these two points by examining seven patients who underwent surgery at the department of thoracic surgery (Osaka Red Cross Hospital), during a 10 years period from January 1985 to December 1994. Antituberculotics were administered to these patients for an average of 3.9 months before surgery, but in vain. Therefore, they were surgically treated. In all cases, the incision was closed at once, and there were no severe complications. The signs and symptoms disappeared soon after surgery. It has been reported that the medical treatment leads to recovery or tendency to recovery within three months of drug administration. The conditions of pericostal tuberculosis patients during this period can be used as indicators to decide whether or not to carry out surgical treatment. Also, by active excision of the rib and tumor as one mass, and by administering antituberculotic for 13.1 months after surgery, no relapse took place during the follow-up period (average 37.4 months). And the postoperative respiratory functions did not decrease compared to those before surgery.

Epithelial barrier function of the filtering bleb conjunctiva and the cornea after trabeculectomy with mitomycin C

PURPOSE

To evaluate epithelial barrier function of the filtering bleb conjunctiva and the cornea after trabeculectomy with adjunct, intraoperative mitomycin C, by using a newly developed slit-lamp fluorophotometer.

SUBJECTS AND METHODS

Thirteen patients with normal-tension glaucoma with a cystic filtering bleb who had undergone unilateral trabeculectomy with mitomycin C only once at least 1 year previously were subjected to the study. Epithelial barrier function of the bleb conjunctiva and the cornea in the operated eye was evaluated using an Anterior Fluorometer FL-500 to measure the uptake of topically applied fluorescein.

RESULTS

Fluorescein uptake (nanograms per milliliter, mean +/- standard error) by the bleb conjunctiva (1,857 +/- 380) was not significantly different from either the uptake by the superior bulbar conjunctiva in the operated eyes, located approximately 90 degrees C away from the filtering bleb (1,974 +/- 258), or the uptake by the conjunctiva in the intact eyes, located symmetrically against the bleb (1,913 +/- 248). The corneal uptake in the operated eye (56.1 +/- 10.2) was not significantly different from that in the intact eye (53.5 +/- 8.3).

CONCLUSIONS

Epithelial barrier function of the cystic filtering bleb conjunctiva and the cornea long after trabeculectomy with mitomycin C was demonstrated to be almost identical to that of the control.

Quantitative analysis of vascular endothelial growth factor in primary breast cancer

BACKGROUND

Recent clinical studies have demonstrated that tumor angiogenesis is a potent prognostic indicator for breast cancer patients. The quantitation of endothelial growth factors is thought to be useful to assess angiogenic phenotype in the tumor. Among the many new endothelial growth factors, vascular endothelial growth factor (VEGF) is known to be particularly responsible for promoting the neovascularization in human breast cancer.

METHODS

Intratumoral protein levels of VEGF were measured by enzymatic immunoassay in 135 primary breast cancer tissues. The VEGF levels were compared with the microvessel density evaluated by immunostaining the endothelial antigen and also were compared with intratumoral protein levels of other endothelial growth factors, including basic fibroblast growth factor (bFGF) and hepatocyte growth factor (HGF).

RESULTS

Intratumoral VEGF concentrations varied from 3.3 pg/mg protein to 2032 pg/mg protein (average 148 pg/mg protein). An immunocytochemical analysis using anti-VEGF antibody confirmed that VEGF was located mainly in the cytoplasm of the tumor cells. The VEGF concentrations were significantly higher in vascularly rich tumors than in vascularly poor tumors. No significant association was found between VEGF concentrations and the two other endothelial growth factor concentrations.

CONCLUSIONS

The quantitation of intratumoral VFGF levels seems to be useful for assessing the activity of tumor angiogenesis.

Ca2+-dependent and Ca2+-independent protein kinase C changes in the brain of patients with Alzheimer's disease

We examined protein kinase C (PKC) activity in Ca2+-dependent PKC (Ca2+-dependent PKC activities) and Ca2+-independent PKC (Ca2+-independent PKC activities) assay conditions in brains from Alzheimer's disease (AD) patients and age-matched controls. In cytosolic and membranous fractions, Ca2+-dependent and Ca2+-independent PKC activities were significantly lower in AD brain than in control brain. In particular, reduction of Ca2+-independent PKC activity in the membranous fraction of AD brain was most enhanced when cardiolipin, the optimal stimulator of PKC-epsilon, was used in the assay; whereas Ca2+-independent PKC activity stimulated by phosphatidylinositol, the optimal stimulator of PKC-delta, was not significantly reduced in AD. Further studies on the protein levels of Ca2+-independent PKC-delta, PKC-epsilon and PKC-zeta in AD brain revealed reduction of the PKC-epsilon level in both cytosolic and membranous fractions, although PKC-delta and PKC-zeta levels were not changed. These findings indicated that Ca2+-dependent and Ca2+-independent PKC are changed in AD, and that among Ca2+-independent PKC isozymes, the alteration of PKC-epsilon is a specific event in AD brain, suggesting its crucial role in AD pathophysiology.

Influence of oocyte aging on developmental ability of reconstituted embryos produced from oocyte cytoplast and single blastomeres of two-cell stage embryos

The present study was conducted to investigate the influence of aging of recipient oocyte on the developmental ability of reconstituted mouse embryos produced from the cytoplast of oocytes and single blastomeres of early or late 2-cell stage embryos by electrofusion. Oocytes were obtained at 14 (newly ovulated oocytes), 18, 22 (oocyte that time passed after ovulation; aged oocyte) hr after hCG injection and oocyte cytoplast was produced by manual enucleation using a fine glass needle under the dissecting microscope. The aging of the oocytes significantly influenced on the fusion rate of the reconstituted embryos (14 hr: 42.7-47.2% vs. 22 hr: 75.3-77.6%). Similarly, the cleavage rate of reconstituted embryos increased with aging of the oocytes (14 hr: 50.8-56.3% vs. 22 hr: 82.2-90.7%). The percentage of reconstituted embryos produced from cytoplast of aged oocytes (22 hr post hCG) and single blastomeres of late 2-cell stage embryos developing to the blastocyst (20.8%) was significantly higher than that of reconstituted embryos produced by other combinations (2.0-8.2%: P < 0.01). Although cell cycle stage of donor nuclei influenced to developmental ability of reconstituted embryos, these results are probably related to the aging of the oocytes since aged oocytes can be activated more easily by electrical stimulation than newly ovulated oocytes.

Antiproliferative effect of a novel cholecystokinin-B/gastrin receptor antagonist, YM022

Cholecystokinin (CCK)-B and gastrin receptors are expressed on a variety of human tumor cells. Recently, we have demonstrated that the human brain CCK-B receptors are identical to the gastrin receptors derived from the stomach mucosa, and that the brain-gut peptides, CCK-8 and gastrin I are mitogenic for mouse NIH 3T3 fibroblasts expressing human CCK-B/gastrin receptors (N-hCCKBR). In this report, we evaluated the antiproliferative potency of CCK-B/gastrin receptor antagonists by using N-hCCKBR cells. Among several antagonists, a benzodiazepine derivative, YM022 had the most potent activities in competing with [125I]CCK-8 or [125I]gastrin I binding, inhibition of CCK-8- or gastrin I-induced phosphoinositide hydrolysis and increasing cytoplasmic free calcium. Interestingly, a potent antagonist for rat CCK-B/gastrin receptors did not have such activities in N-hCCKBR cells. YM022 inhibited the CCK-8- or gastrin I-induced [methyl-3H]thymidine incorporation of N-hCCKBR cells in a dose-dependent manner. In the absence of exogenous peptide ligands, YM022 also inhibited the proliferation of several human cancer cell lines expressing the genes for both gastrin and its receptor. These results suggest that YM022 could intervene in the autocrine stimulation of human tumor cell lines through CCK-B/gastrin receptors. N-hCCKBR cells are an excellent tool to screen for novel human CCK-B/gastrin receptor antagonists possessing antiproliferative activity for human cancer cells.

Expression of apolipoprotein E mRNA in rat microglia

Apolipoprotein E (apoE) is a major risk factor for Alzheimer disease (AD), which is the most common cause of progressive dementing illness. ApoE has been postulated to be synthesized by astrocytes and taken up by microglia and neuronal cells. However, it remains unknown whether apoE is also produced by microglia in the brain. We analyzed apoE mRNA expression of microglia using a rat primary culture system. Reverse transcriptase-polymerase chain reaction (RT-PCR) analysis revealed expression of apoE mRNA in cultured rat microglia. By RT-in situ-PCR, microglia showed positive staining for the PCR product of apoE mRNA. These results indicated that apoE was biosynthesized in rat microglia. We suggest that microglia might be one of the sources of apoE in the brain, and that apoE synthesized in microglia might be closely related to the pathogenesis of AD.