Interleukin-8 gene expression in chronic sinusitis

PURPOSE

Interleukin-8 (IL-8), a monocyte-derived and macrophage-derived cytokine, displays potent chemotactic activating properties toward neutrophils and thus may contribute to the pathogenesis of chronic sinusitis. The object of this investigation was to show the expression of the IL-8 gene in chronic sinusitis by Northern blot analysis and a reverse transcription-polymerase chain reaction (RT-PCR).

MATERIALS AND METHODS

For Northern blot analysis, RNAs were extracted from maxillary mucosa and nasal polyps from two patients with chronic sinusitis, respectively, and from the inferior turbinate of a nasal allergy patient. For RT-PCR, RNAs were extracted from 11 patients with chronic sinusitis, 8 patients with allergic rhinitis, and 4 patients with hypertrophic rhinitis.

RESULTS

Whereas IL-8 mRNA was expressed in the maxillary mucosa, IL-8 transcript was not detected in the inferior turbinate by Northern blot analysis. IL-8 transcripts were detected in 45% of chronic sinusitis RNAs (5/11) and in 50% of allergic rhinitis RNAs (5/10) by RT-PCR.

CONCLUSION

These data suggest IL-8 may contribute to neutrophil involvement in chronic sinusitis.

Expression of endogenous retroviruses, ERV3 and lambda 4-1, in synovial tissues from patients with rheumatoid arthritis

We addressed the question of whether or not expression of human endogenous retroviruses (ERV), ERV3 and lambda 4-1, is related to the pathogenesis of rheumatoid arthritis (RA). In genomic Southern hybridization, there were no significant differences between RA patients and healthy volunteers with regard to frequencies of restriction fragment length polymorphism (RFLP) patterns, for either ERV3 or lambda 4-1. By Northern blot analysis using fresh synovial tissues, cultured synovial cells, and peripheral blood mononuclear cells (PBMC) from patients with RA, we noted two molecular species of ERV3 mRNAs of 3.5 kb and 9.0 kb sizes, and one single molecular species of lambda 4-1 mRNAs of 4.2 kb size. The expression was detected not only in RA patients but also in synovial cells from osteoarthritis (OA) as a non-RA control and PBMC from healthy volunteers, and was not related to RA activities or treatments. Although ERV3 and lambda 4-1 expression may not be directly associated with the pathogenic pathway of RA, the possibility exists that human ERV may have a causative role in autoimmune diseases, including RA. We also examined the effect of cytokines on the transcriptional regulation of ERV3. Although the level of ERV3 expression in cultured synovial cells did not change with IL-1 beta treatment, the level for cultured proximal tubular epithelial cells (hKEC) was up-regulated.

Expression of CD44 variant exons 8-10 in colorectal cancer and its relationship to metastasis

Splice variants of CD44 are overexpressed in human lung, breast, and colon carcinoma cell lines. This study was conducted to clarify the association between the expression of CD44 variant exons 8-10 and metastatic potential in human colorectal cancer. We found that the expression of a CD44 splice variant containing exons v8-10 was increased in all of 60 colorectal cancer specimens examined compared with matched normal colerectal mucosa, as determined by Northern blotting. Expression of CD44 variant exons 8-10 did not significantly correlate with histological type, depth of tumor invasion, lymphatic invasion, venous invasion, or lymph node metastasis. However, the level of CD44 variant exon 8-10 expression was significantly higher in carcinomas associated with liver metastasis than in those without liver metastasis. In addition, expression of CD44 variant exons 8-10 in the liver metastases was more intense than that in the primary colorectal cancers. These findings indicated that this domain of the CD44 glycoprotein encoded by exons v8-10 may play an important role in tumor hematogenous metastasis of human colorectal cancer.

Automated measurement of reticulated platelets in estimating thrombopoiesis

We described a fully automated measurement of reticulated platelets using a fluorescent dye, auramine O, and a reticulocyte counter, the R-3000, equipped with special software. Reproducibility and linearity were shown to be good. In the normal subjects studied (n = 60), the mean value for reticulated platelets was 0.98% +/- 0.41% and the mean absolute count was 2.12 +/- 0.69 x 10(9)/l. The absolute count for reticulated platelets was significantly lower (p < 0.05) in patients with reduced thrombopoiesis as seen in acute myeloblastic leukemia, aplastic anemia or chemotherapy-induced thrombocytopenia and it was elevated (p < 0.05) in essential thrombocythemia and in chronic myelocytic leukemia with thrombocytosis. All 20 patients with chronic idiopathic thrombocytopenic purpura had a high percentage of reticulated platelets. The percentage of reticulated platelets was significantly increased (p < 0.05) in patients with impaired thrombopoiesis despite the reduction in the absolute count. In 2 leukemic patients, an apparent rise was noticed in the percentage of reticulated platelets which preceded by several days a progressive increase in the platelet count at the recovery phase of thrombocytopenia. The results suggest that an automated measurement of reticulated platelets can be applied to routine laboratories for clinical use.

Role of the sympathetic nervous system in gastric functional changes induced by thyrotropin-releasing hormone in rats

We determined the changes in gastric functions and systemic blood pressure in response to thyrotropin-releasing hormone (TRH) simultaneously in anesthetized rats and examined the role of the sympathetic nervous system in these changes. TRH injected i.c. increased gastric acid secretion, contraction and mucosal blood flow, and produced hemorrhagic lesions in the glandular stomach. These responses to TRH were almost completely inhibited by bilateral cervical vagotomy or atropine. The increased gastric acid secretion and contraction in response to TRH were significantly augmented by pretreatment with yohimbine but not with prazosin. Bilateral adrenalectomy also potentiated the gastric acid secretory and contractile responses to TRH. Neither prazosin, yohimbine nor adrenalectomy had any appreciable effect on the increased gastric mucosal blood flow induced by TRH. TRH-induced gastric mucosal lesions were significantly aggravated by yohimbine and adrenalectomy. In vagotomized rats, TRH significantly suppressed the gastric functional changes induced by electrical stimulation of the vagus nerves. These data suggest that while gastric functional changes and mucosal lesions induced by TRH mainly occur through stimulation of the vagus nerves, these responses are extensively modified by the sympathetic nervous system including the adrenal glands.

[The development of a tissue calcium-detecting apparatus]

Calcium phosphate is deposited in tissues with progression of aging and arteriosclerosis, causing impairments of organ functions. Localization and quantification of tissue calcium phosphate are important for elucidation of the cause of this calcium phosphate deposition. Tissue calcium phosphate has been detected by Von Kossa-Nishiyama staining using the heavy metal substitution technique. By this method, however, the reaction was weak because of the use of sunbeam as the light source, and consistent detection was difficult. Especially, fine calcium phosphate granules that appear in early stages of the pathological changes could not be detected. Therefore, we evaluated a method for preparation of tissue specimens, light source, filter, and staining conditions, and developed a more reliable method for detection and assay of tissue calcium phosphate. The human aortic tissue was fixed with formalin, embedded with paraffin, and cut to a thickness of 4 microns using a glass knife. Solax-XCA100B, an artificial sunbeam lamp with a spectrum nearly identical with that of the sun, was used as the light source. A B filter, which selectively filters out the wavelengths 290nm or less and 800-1,000nm, was used. The appearance of abnormal granules due to excessive reaction could be prevented by eliminating ultraviolet rays with wavelengths of 290nm or less, and burning of the tissue and the appearance of silver particles could be prevented by excluding infrared rays with wavelengths of 800nm or above. Distilled water was continuously dripped into the reaction solution to prevent an increase in the concentration due to evaporation. The reaction showed appreciable progression until after 40 minutes and stopped completely after 80 minutes.(ABSTRACT TRUNCATED AT 250 WORDS)

cDNA cloning of mouse VLA-3 alpha subunit

cDNA clones for mouse VLA (very late antigen)-3 alpha subunit (alpha 3 integrin) were isolated and sequenced. The encoded mouse alpha 3 integrin subunit was composed of 1,053 amino acid residues. The results of sequence analysis revealed similar structural characteristics of other VLA alpha subunits. For example, the presence of a large extracellular domain including three putative metal binding sequences, a transmembrane domain, and a short cytoplasmic domain. A higher level of its message was detected in thymus than in kidney, stomach, spleen, liver, brain, or lung by Northern blotting analysis.

Irritant and protective action of urea-urease ammonia in rat gastric mucosa. Different effects of ammonia and ammonium ion

The effects of urea-urease-ammonia on the rat gastric mucosa were examined and compared with those of NH4OH and NH4Cl. The mucosal application of urea with urease produced a reduction in potential difference (PD) in a dose-related manner for urea, and a significant drop was observed by > 0.1% urea in the presence of 100 units urease. Such PD reduction was also observed when the mucosa was exposed to either NH4OH (> 0.03%) or NH4Cl (> 1%); delta PD (20 mV) caused by 0.3% NH4OH and 3% NH4Cl was equivalent to that induced by 0.5% urea+urease (100 units). The combined oral administration of urea (approximately 6%) and urease (100 units) did not induce any macroscopic damage in the gastric mucosa. NH4Cl given orally had no or little effect on the mucosa at any dose levels even at 10%, while NH4OH given orally caused hemorrhagic lesions in the mucosa at the dose of > 0.3%. In contrast, both urea+urease and NH4Cl given prior to HCl/ethanol protected the gastric mucosa against damage in a dose-related manner, and a significant effect was obtained by urea at > 0.5% and by NH4Cl at > 1%. NH4OH was also effective in reducing the severity of HCl/ethanol-induced gastric lesions at lower dose (0.3%). The protective effect of urea+urease was attenuated significantly by prior administration of indomethacin or coadministration of hydroxyurea, while that of NH4Cl or NH4OH was mitigated by indomethacin.(ABSTRACT TRUNCATED AT 250 WORDS)

Cine magnetic resonance imaging of aqueductal stenosis

Cerebral aqueductal stenosis is one of the most common causes of congenital and acquired hydrocephalus, but the etiology, pathophysiology and cerebrospinal fluid (CSF) dynamics of aqueductal stenosis have yet to be clarified. Utilizing cardiac gated cine magnetic resonance (MR) imaging, we evaluated aqueductal configuration and pulsatile motion of brain and CSF flow stimulated by cardiac pulsation in five patients with non-tumoral aqueductal stenosis. Cine MR of four cases revealed obliteration of the aqueduct by thickening mesencephalic tectum, turbulent CSF flow in the III ventricle, and absence of flow-related signal void, which in all normal cases indicates CSF movement within the aqueduct. In the remaining fifth case, with proximal dilation of the aqueduct resulting from thinning of the tectum, distortion of caudal (distal) tectum related to pulsatile motion of the brain caused funnel-like narrowing of the aqueduct, leading to incomplete obstruction and the absence of upward CSF flow during diastole.

Analysis of the autoantibody response to fibrillarin in human disease and murine models of autoimmunity

Fibrillarin, a component of the U3 RNP particle, is a target for the spontaneously arising autoantibodies in human scleroderma and a monoclonal autoantibody (72B9) derived from the autoimmune mouse strain (NZB x NZW) F1. Autoantibodies against fibrillarin can also be induced in H-2s mice by treatment with mercuric chloride (HgCl2). The objective of this study was to compare the spontaneously occurring anti-fibrillarin autoantibody response with the autoantibody response induced by HgCl2 treatment. Immunofluorescence microscopy on human HEp2, mouse 3T3, and Xenopus XIK-2 cells, immunoblotting with use of nuclear extract from human MOLT-4, mouse 3T3, and Xenopus XIK-2 cells, and immunoprecipitation with use of in vitro translation products of RNA transcripts from yeast fibrillarin cDNA were used in this analysis. Both spontaneous and induced autoantibodies displayed common reactivity in that, irrespective of the antigenic source, they gave the same nucleolar immunofluorescence pattern and a restricted immunoblotting reactivity targeting predominantly the 34-kDa protein fibrillarin. Immunoprecipitation of N- and C-terminal truncated fibrillarin constructs also demonstrated a common pattern of reactivity. All Abs precipitated a fragment comprising amino acids 1-312 but not a smaller fragment containing amino acids 1-257. The majority of sera could not precipitate an N-terminal truncated molecule consisting of amino acids 157-327. These immunoprecipitation experiments support recognition of a common epitope requiring both N- and C-regions, which may be exemplified by the reactivity of murine monoclonal anti-fibrillarin autoantibody 72B9. Our results indicate that spontaneous human and toxin-induced murine autoantibodies to fibrillarin share common reactivity against this highly conserved nucleolar protein.

Analysis of the autoantibody response to fibrillarin in human disease and murine models of autoimmunity

Fibrillarin, a component of the U3 RNP particle, is a target for the spontaneously arising autoantibodies in human scleroderma and a monoclonal autoantibody (72B9) derived from the autoimmune mouse strain (NZB x NZW) F1. Autoantibodies against fibrillarin can also be induced in H-2s mice by treatment with mercuric chloride (HgCl2). The objective of this study was to compare the spontaneously occurring anti-fibrillarin autoantibody response with the autoantibody response induced by HgCl2 treatment. Immunofluorescence microscopy on human HEp2, mouse 3T3, and Xenopus XIK-2 cells, immunoblotting with use of nuclear extract from human MOLT-4, mouse 3T3, and Xenopus XIK-2 cells, and immunoprecipitation with use of in vitro translation products of RNA transcripts from yeast fibrillarin cDNA were used in this analysis. Both spontaneous and induced autoantibodies displayed common reactivity in that, irrespective of the antigenic source, they gave the same nucleolar immunofluorescence pattern and a restricted immunoblotting reactivity targeting predominantly the 34-kDa protein fibrillarin. Immunoprecipitation of N- and C-terminal truncated fibrillarin constructs also demonstrated a common pattern of reactivity. All Abs precipitated a fragment comprising amino acids 1-312 but not a smaller fragment containing amino acids 1-257. The majority of sera could not precipitate an N-terminal truncated molecule consisting of amino acids 157-327. These immunoprecipitation experiments support recognition of a common epitope requiring both N- and C-regions, which may be exemplified by the reactivity of murine monoclonal anti-fibrillarin autoantibody 72B9. Our results indicate that spontaneous human and toxin-induced murine autoantibodies to fibrillarin share common reactivity against this highly conserved nucleolar protein.

Nitric oxide and prostaglandins in regulation of acid secretory response in rat stomach following injury

The gastric mucosa responds to taurocholate (TC) by significantly decreasing acid secretion. We examined the role of nitric oxide (NO) in this phenomenon in comparison with endogenous prostaglandins. A rat stomach was mounted in an ex-vivo chamber and perfused with saline, and the potential difference, luminal pH and acid responses were measured before and after the application of 20 mM TC for 30 min with or without pretreatment with the NO synthase inhibitor NG-nitro-L-arginine methyl ester (L-NAME) or the cyclooxygenase inhibitor indomethacin. Exposure of the stomach to TC caused a reduction in potential difference, a decrease in acid secretion and an increase in luminal HCO3-. Pretreatment with L-NAME or indomethacin did not affect potential difference and HCO3- responses, but it significantly attenuated the decrease in acid secretion caused by TC. The effect of L-NAME was more potent than that of indomethacin, and, especially in the presence of L-NAME, acid secretion was actually enhanced after exposure to TC. Aminoguanidine, the selective inhibitor of inducible NO synthase, did not have any significant effect on either parameter. This effect of L-NAME was antagonized by the simultaneous administration of L-arginine but not by that of D-arginine, whereas the effect of indomethacin was reversed by PGE2. Acid secretion in normal stomachs was significantly reduced by nitroprusside and PGE2 but was not affected by either L-NAME or indomethacin.(ABSTRACT TRUNCATED AT 250 WORDS)

Mucosal ulceration in isolated amphibian stomachs in vitro. Roles of nutrient HC03- and endogenous prostaglandins

We examined the effects of nonsteroidal anti-inflammatory drugs (NSAIDs) on mucosal ulceration in isolated bullfrog stomachs and investigated the roles of endogenous prostaglandins (PGs) and nutrient HCO3- in the mucosal protection in vitro. Gastric sacs were prepared by separation from the muscle layer and incubation for 1-8 h in HCO3--Ringer's solution gassed with 95% 02/5% CO2 or PO3(-)4-Ringer's solution gassed with 100% 02 in the presence of histamine (1 x 10(-4) M). Under these conditions, multiple ulcers developed in the mucosa only when the gastric sacs were incubated in HCO3--free nutrient solution; both the number and severity of ulcers increased with time and reached a maximum after 6 h of incubation. Luminal pH was decreased because of stimulation of acid secretion by histamine, irrespective of whether the mucosa was bathed in Ringer's solution with or without HCO3-, while gastric potential difference was reduced only in the mucosa bathed in HCO3--free nutrient solution. 16,16-Dimethyl PGE2 added to the nutrient side significantly reduced the number of ulcers developed in the mucosa bathed in HCO3--free nutrient solution. In contrast, indomethacin and aspirin, but not salicylate, caused ulceration even in the mucosa bathed in HCO3--nutrient solution. Histamine-induced acid secretion was reduced by 16,16-dimethyl PGE2 but not affected by these NSAIDs. In conclusion, ulceration of the isolated gastric mucosa in the presence of acid depends upon either a deficiency of endogenous PGs or a lack of nutrient HCO3-/CO2.

Experimental osteodystrophy of chronic renal failure induced by aluminum- and ferric-nitrilotriacetate in Wistar rats

The aluminum (AI) and iron (Fe) chelate complexes of nitrilotriacetate (NTA) cause renal insufficiency when they are administered intraperitoneally to rats. Their effects on bone metabolism were studied in 4 week old Wistar rats. Daily intraperitoneal administration of AI-NTA (3mg AI/kg for 11 weeks) induced osteomalacia, impaired bone growth, decreased bone mineral density, lower serum PTH levels than normal as well as renal insufficiency. Al staining showed diffuse deposition in the trabecula and a strong linear band of aluminum deposited at the mineralization front and along the cement line. The osteoid seen markedly within the trabecula was probably the decalcified portion of the bone, the calcium apatite of which was defectively fabricated because of diffuse Al deposition in the trabecula. Al deposition along the cement line would make it much more susceptible to external shear stress than normal. Although daily intraperitoneal administration of Fe-NTA (6 mg Fe/kg for 11 weeks) caused impaired bone growth, decreased bone mineral content and renal insufficiency, the osteoid volume did not increase. Fe staining showed that Fe was deposited diffusely in the cytoplasm of osteoblasts. The results of this study demonstrated that during renal insufficiency, different minerals exhibit different modes of action on bone metabolism, and that Al-NTA is useful for experimental animal models of Al-induced osteomalacia in renal insufficiency.

[Stereotactic radiosurgery with the gamma knife for brain metastases in patients with lung cancer]

Between February 1992 and April 1993, six patients with lung cancer were treated with gamma knife radiosurgery for brain metastases. Five patients had adenocarcinoma, and one patient had small cell carcinoma. Two patients had solitary metastases, and four patients had multiple metastases. Twelve metastases were treated with the gamma knife (peripheral dose between 12 Gy and 25 Gy). After radiosurgery, three complete and eight partial responses were achieved, which resulted in an overall response rate of 92%. In two patients, histological studies showed that few viable cells were surrounded by necrosis. Neurological status improved in all patients, and none died of complications. However, four of six patients later developed new intracranial metastases outside the treatment field. These data suggest that radiosurgery with the gamma knife is effective against brain metastases in patients with lung cancer, especially when the lesions are deep in the brain.

Surface antigens on eosinophils in bronchial asthma and eosinophilic pneumonia

Surface antigens on peripheral blood eosinophils from 23 patients with bronchial asthma, 6 with eosinophilic pneumonia and 8 controls were examined using a new direct method. Peripheral blood eosinophils in bronchial asthma and eosinophilic pneumonia showed higher complexity and/or granularity than those from controls. The percentage expression of HLA DR, CD4 and CD45RO on peripheral blood eosinophils from patients with bronchial asthma were increased compared with those from patients with eosinophilic pneumonia and from the controls. These results suggest that peripheral blood eosinophils in bronchial asthma may play a role in immunoregulation via the expression of human leukocyte antigens, such as HLA-DR, CD4 and CD45RO, that interact with lymphocytes, and may function as antigen-presenting cells. Furthermore this study suggests that there may be different phenotypes of eosinophils with differing surface antigens and intercellular reactions between eosinophils and lymphocytes.

Effect of prolonged beta-adrenergic blockade induced by atenolol on left ventricular remodeling after acute myocardial infarction in the rat

Beta-adrenergic receptor blockade reduces the mortality rate after acute myocardial infarction (AMI) in humans. However, the effects of beta blockade on left ventricular remodeling remain unknown. Therefore, in the present study we investigated the effect of prolonged beta-adrenergic receptor blockade with atenolol on left ventricular remodeling following AMI in rats. Myocardial infarction (MI) was produced in Wistar-Kyoto rats by ligating the coronary artery. Four groups of rats were studied: sham-operated (n = 10); atenolol (1 g/l in drinking water) treated sham-operated (n = 8); untreated MI (n = 11); atenolol treated MI (n = 10). Hemodynamic measurements were made about 3 weeks after the operation. Infarct size was similar in treated and untreated MI rats (31.2 +/- 2.5% cf. 33.5 +/- 2.0%). MI rats were characterized by increases in left ventricular end-diastolic pressure (LVEDP), right atrial pressure (RAP), right ventricular systolic pressure (RVSP), and left ventricular end-diastolic volume index (LVEDVI), as compared with sham-operated rats. In sham-operated rats, prolonged beta-adrenergic receptor blockade produced only a reduced HR. Atenolol-treated MI rats had a significantly higher LVEDP, RAP and LVEDVI than did rats with untreated MI. Prolonged beta-adrenergic receptor blockade with atenolol appeared to promote left ventricular remodeling after AMI. Thus, the treatment of AMI with beta-adrenergic receptor blockade in the clinical setting should be evaluated with respect to ventricular remodeling during prolonged therapy.

Influences of urethane anesthesia on indomethacin-induced gastric mucosal lesions in rats. Relation to blood glucose levels

Effects of urethane on gastric motility and mucosal ulcerogenic responses induced by indomethacin were investigated in the rat in relation to blood glucose levels (BGL) and compared with those of pentobarbital Na. Urethane (1.25 g/kg) given intraperitoneally, caused a progressive and significant rise in BGL, while pentobarbital (30 mg/kg) given intraperitoneally did not affect BGL. Subcutaneous administration of indomethacin (25 mg/kg) caused high-amplitude gastric contractions and induced hemorrhagic lesions in the stomachs of conscious rats. These lesions were significantly inhibited by urethane but not pentobarbital. Administration of urethane abolished basal gastric motility and almost completely suppressed the motility responses induced by indomethacin, while pentobarbital did not have much effect on gastric motility under basal and indomethacin-stimulated conditions. Acid secretion was significantly decreased by urethane and increased by pentobarbital. Pretreatment of the animals with yohimbine (5 mg/kg, subcutaneously) but not prazosin (0.5 mg/kg) inhibited the elevation in BGL seen after administration of urethane and allowed resumption both gastric motility and ulcerogenic responses induced by indomethacin, with less change in acid secretion. These results suggest that intraperitoneal administration of urethane prevented indomethacin-induced gastric lesions, probably by inhibiting the enhanced gastric motility response, and this effect may relate to its hyperglycemic action mediated by alpha 2-adrenoceptors. These findings also provide further evidence to support the importance of gastric motility in the pathogenesis of these lesions.

Capsaicin-sensitive sensory neurons in healing gastric lesions induced by HCl in rats

The role of capsaicin-sensitive sensory neurons in the healing of HCl-induced gastric lesions was investigated in rats. Rats fasted for 18 hr were given 0.6 N HCl orally for induction of gastric lesions, and they were fed normally from 1 hr later. On various days after HCl treatment, area of lesions, acid secretion, mucosal H+ permeability, and blood flow responses were measured. Functional ablation of capsaicin-sensitive sensory neurons was performed two weeks before the experiment by subcutaneous injections of high-dose capsaicin. Sensory deafferentation did not affect the development of gastric damage in response to HCl but significantly delayed the healing of these lesions. The mucosa damaged by HCl secreted less acid but showed significant rise in H+ permeability, resulting in acid back-diffusion accompanied by an increase of mucosal blood flow. Sensory deafferentation had no effect on acid secretion and mucosal permeability changes in the damaged stomach but completely blocked the hyperemic response caused by acid back-diffusion. Capsaicin-sensitive sensory neurons may contribute to healing of gastric lesions, probably by mediating the mucosal hyperemic responses associated with acid back-diffusion and by facilitating acid disposal in the mucosa.

Transforming growth factor beta 1 and extracellular matrix gene expression in isoprenaline induced cardiac hypertrophy: effects of inhibition of the renin-angiotensin system

OBJECTIVE

The aim was to investigate changes in cardiac transforming growth factor beta 1 (TGF-beta 1), fibronectin, and collagen types I and III mRNA levels in isoprenaline induced cardiac hypertrophy, and the effects of delapril, an angiotensin converting enzyme inhibitor, and TCV-116, an angiotensin II type 1 receptor antagonist, on this hypertrophy.

METHODS

Rats were continuously infused with saline and low or high dose of isoprenaline (0.5 or 3 mg.kg-1.d-1) by an osmotic minipump for 24 h, 48 h or 7 d. Treatment with delapril (100 mg.kg-1.d-1) or TCV-116 (10 mg.kg-1.d-1) was started from 1 d before the implantation of minipump to the end of experiments. After the experimental periods, left ventricular weight was measured and the mRNA was extracted and measured by northern blot hybridisation.

RESULTS

Both low and high doses of isoprenaline infusion resulted in increased left ventricular weight. With low dose infusion, cardiac TGF-beta 1 mRNA was not stimulated throughout the infusion, while fibronectin mRNA and collagen types I and III mRNAs began to increase at 24 h and 48 h, respectively, after the infusion. In high dose isoprenaline infusion, not only was extracellular matrix mRNA but also TGF-beta 1 mRNA in the ventricle significantly increased. TCV-116 prevented isoprenaline induced left ventricular hypertrophy as much as delapril. However, with delapril or TCV-116, the time course of TGF-beta 1 and ECM mRNA expression was almost similar to isoprenaline infusion only.

CONCLUSIONS

The extracellular matrix mRNA expressions are enhanced in myocardial hypertrophy by a low dose of isoprenaline, which is probably not mediated by TGF-beta 1. The preventive effects of TCV-116 on this hypertrophy indicate that the inhibitory effects of angiotensin converting enzyme inhibitor on cardiac hypertrophy are due to the inhibition of angiotensin II and that angiotensin II type I receptor plays an important role in isoprenaline induced left ventricular hypertrophy. However, the renin-angiotensin system may play a minor role in isoprenaline induced cardiac fibrosis.

Mechanisms underlying stimulation of gastroduodenal HCO3- secretion by NG-nitro-L-arginine methyl ester, an inhibitor of nitric oxide synthase, in rats

We investigated the mechanism underlying stimulation of HCO3- secretion by the nitric oxide (NO) synthase inhibitor NG-nitro-L-arginine methyl ester (L-NAME) in the gastroduodenal mucosa of anesthetized rats. A chambered stomach (in the presence of omeprazole) or a duodenal loop was perfused with saline, and HCO3- secretion was measured at pH 7.0 by a pH-stat method. Intravenous administration of L-NAME increased gastroduodenal HCO3- secretion with a concomitant rise in arterial blood pressure and a decrease in heart rate, and the changes were all antagonized by simultaneous administration of L-arginine. Vagotomy had no effect on the increased blood pressure response, but significantly inhibited the decrease of heart rate and increase of HCO3- secretion caused by L-NAME. The HCO3- stimulatory action of L-NAME was also inhibited by prior administration of yohimbine or prazosin. These agents alone lowered blood pressure and reduced the magnitude of the blood pressure response caused by L-NAME, leading to inhibition of heart rate changes. When delta HCO3- output induced by L-NAME was plotted against delta blood pressure change (from basal values) under various conditions, a significant relationship was found between these two factors. These results suggest that L-NAME stimulates gastroduodenal HCO3- secretion in association with the inhibition of endogenous NO production, and this mechanism may be in part mediated by a neural reflex through the vagal efferent nerve, resulting from the pressor response to L-NAME.

Effect on fusion induction of point mutations introduced into the F protein of mumps virus

We have tested the effect of substitution of an amino acid at position 195 of the F protein of mumps virus on cell-to-cell fusion caused by the virus. Introduction of amino acids with aromatic side chains into this position resulted in reduction of fusion induction. Furthermore the F protein was not cleaved when the amino acid at this position was substituted by several amino acids, suggesting that the amino acid at this position was essential to keep the tertiary structure of the protein that might be required not only for proper folding of the protein but also for induction of membrane fusion.