Equilibrium and kinetic studies on folding of the authentic and recombinant forms of human alpha-lactalbumin by circular dichroism spectroscopy

The equilibrium and kinetics of the unfolding and refolding of authentic and recombinant human alpha-lactalbumin, the latter of which had an extra methionine residue at the N-terminus, were studied by circular dichroism spectroscopy, and the results were compared with the results for bovine and goat alpha-lactalbumins obtained in our previous studies. As observed in the bovine and goat proteins, the presence of the extra methionine residue in the recombinant protein remarkably destabilized the native state, and the destabilization was entirely ascribed to an increase in the rate of unfolding. The thermodynamic stability of the native state against the unfolded state was lower, and the thermodynamic stability of the molten globule state against the unfolded state was higher for the human protein than for the other alpha-lactalbumins previously studied. Thus, the population of the molten globule intermediate was higher during the equilibrium unfolding of human alpha-lactalbumin by guanidine hydrochloride. Unlike the molten globule states of the bovine and goat proteins, the human alpha-lactalbumin molten globule showed remarkably more intense circular dichroism ellipticity than the native state in the far-ultraviolet region below 225 nm. During refolding from the unfolded state, human alpha-lactalbumin thus exhibited overshoot kinetics, in which the alpha-helical peptide ellipticity exceeded the native value when the molten globule folding intermediate was formed in the burst phase. The subsequent folding involved reorganization of nonnative secondary structures. It should be noted that the rate constant of the major refolding phase was approximately the same among the three types of alpha-lactalbumin and that the rate constant of unfolding was accelerated 18-600 times in the human protein, and these results interpreted the lower thermodynamic stability of this protein.

ATP hydrolytic activity of an iron-stimulated P-type ATPase of mouse liver microsomes

Mouse liver microsomes treated with octylthioglucoside were examined for iron-stimulated ATPase activity. The activity was about 6 mumol Pi/mg protein/hr under optimal conditions [300 mM KC1, 3 mM MgSO4, 10 mM glutathione(GSH), 100 microM FeCl3, 3 mM ATP and 50 mM acetate buffer at pH 5.0]. The Km for iron was 20 microM. A reducing agent, such as GSH or dithiothreitol, was required for the activity, and removal of Fe2+ from the reaction mixture by bathophenan-throlinedisulfonate resulted in a complete loss of the iron-stimulated ATPase activity. Vanadate inhibited the iron-stimulated ATPase activity. These results suggest that microsomes from mouse liver contain the Fe(2+)-stimulated P-type ATPase.

Purification and characterization of a novel secondary fimbrial protein from Porphyromonas gingivalis strain 381

We previously reported the existence of two different kinds of fimbriae expressed by Porphyromonas gingivalis ATCC 33277. In this study, we isolated and characterized a secondary fimbrial protein from strain FPG41, a fimA-inactivated mutant of P. gingivalis 381. FPG41 was constructed by a homologous recombination technique using a mobilizable suicide vector, and failed to express the long fimbriae (41-kDa fimbriae) that were produced on the cell surface of P. gingivalis 381. However, short fimbrial structures were observed on the cell surface of FPG41 by electron microscopy. The fimbrial protein was purified from FPG41 by DEAE-Sepharose CL-6B column chromatography. The secondary fimbrial protein was eluted at 0.15 M NaCl, and the molecular mass of this protein was approximately 53 kDa as estimated by SDS-PAGE. An antibody against the 53-kDa fimbrial protein reacted with the short fimbriae of the FPG41 and the wild-type strain. However, the 41-kDa long fimbriae of the wild-type strain and the 67-kDa fimbriae of ATCC 33277 did not react with the same antibody. Moreover, the N-terminal amino acid sequence of the 53-kDa fimbrial protein showed only 2 of 15 residues that were identical to those of the 41-kDa fimbrial protein. These results show that the properties of the 53-kDa fimbriae are different from those of the 67-kDa fimbriae of ATCC 33277 as well as those of the 41-kDa fimbriae.

Laparoscopic surgery in neonates and infants weighing less than 5 kg

BACKGROUND

Laparoscopic surgery in small infants is still an uncommon procedure in Japan. The present study was conducted to evaluate the advantages and disadvantages of laparoscopic surgery in neonates and infants weighing less than 5 kg.

METHODS

Between July 1997 and November 1999, 54 infants underwent laparoscopic surgery. They were evaluated for length of operation, intra- and postoperative complications, changes in intra-operative body temperature, time to postoperative feeding, length of hospital stay and changes in serum levels of C-reactive protein (CRP), creatinine phosphokinase (CPK) and interleukin (IL)-6 on days 0, 1 and 4. These parameters in the laparoscopic pyloromyotomy (LP) and laparoscopic fundoplication groups were compared with those in the open pyloromyotomy (OP) and open fundoplication groups, respectively, which were performed during the same period.

RESULTS

Three laparoscopy cases were converted to open procedures. One case of fundoplication had panperitonitis due to failed gastrostomy and required long-term parenteral nutrition. Time to postoperative feeding and length of hospital stay in the LP group were significantly shorter than in the OP group. In LP group, intra-operative body temperature did not markedly decrease during CO, pneumoperitoneum. Although serum levels of CRP, CPK and IL-6 were elevated in all groups on postoperative day 1, there were no significant differences between the groups.

CONCLUSIONS

Better quality of life after laparoscopy is a significant advantage over conventional surgical procedures. This advantage not only outweighs the incidence of intra- and postoperative complications in small infants, but further emphasizes the need to improve laparoscopic techniques to avoid complications.

The use of human hematopoietic growth factors (rhGM-CSF and rhEPO) as a supportive therapy for FIV-infected cats

Recombinant human GM-CSF (rhGM-CSF) and erythropoietin (rhEPO) were tested on chronically FIV-infected laboratory cats and uninfected specific-pathogen-free (SPF) cats. In Study 1, a total of eight cats (four cats per group of either infected or uninfected cats) received subcutaneous injection (twice a day) for 2 weeks with 5 microg/kg of rhGM-CSF, while seven cats (three SPF and four FIV-infected cats) served as the placebo-treated control cats. Four of eight rhGM-CSF-treated cats (two cats each from infected and uninfected groups) developed elevated WBC counts which peaked at Days 5-8 of treatment when compared to placebo-treated cats. The elevated WBC counts were attributed to the increase in either neutrophils, lymphocytes, eosinophils, monocytes, or their combinations. The RBC counts, platelet counts, and blood chemistry were not significantly affected by the treatment. Anti-rhGM-CSF antibodies were detected in six of eight rhGM-CSF-treated cats by Day 35 post-first treatment. All rhGM-CSF-treated infected cats but no placebo-treated infected cats had 1-2 log increase in FIV load in the PBMC during the treatment. In vitro studies suggest that rhGM-CSF has an effect on FIV replication in T cells but not in alveolar macrophages. Five of eight rhGM-CSF-treated cats had low-grade fever at 3-6 days of treatment. In Study 2, four cats per group of either infected or uninfected cats were treated (subcutaneously once a day) three times a week for 2 weeks with 100U/kg of rhEPO and monitored as before, while seven cats (three SPF and four FIV-infected cats) served as the placebo-treated control cats. All rhEPO-treated cats had a gradual increase in RBC, Hgb, and PCV counts which peaked at 2-4 weeks post-first rhEPO treatment, whereas none of the placebo-treated cats had significant increase in these parameters. The rhEPO-treated cats also developed elevated WBC counts consisting of either elevated neutrophils, lymphocytes, or their combination by 4 weeks post-first treatment but there was no statistical difference between rhEPO-treated and placebo-treated groups. None of the cats developed anti-rhEPO antibodies and no remarkable changes in blood chemistry, clinical signs, and FIV loads or FIV antibody titers were observed. Overall, rhEPO can be used safely on FIV-infected cats but the use of rhGM-CSF on FIV-infected cats should be performed with discretion.

Partial functional recovery of paraplegic rat by adenovirus-mediated gene delivery of constitutively active MEK1

Spinal cord injury in adult mammals results in little axonal regeneration, although the mechanism of regeneration failure still remains elusive. Recent research has revealed that activation of the extracellular-signal-regulated kinases (ERKs) plays an important role in the neurite outgrowth. In the present study, we constructed a replication-defective adenovirus vector carrying mutated form of MEK1 (CA-MEK virus), which constitutively activate ERK pathway, and investigated its effect on thoracic spinal cord injury model in young adult rats as well as neurite outgrowth in vitro. In rat pheocromocytoma cell line PC12 cells, CA-MEK virus infection induced sustained activation of ERKs and stimulated neurite outgrowth in the absence of neurotrophic factors. In rat spinal cord transection model, injection of CA-MEK virus into the completely transected spinal cord efficiently activated ERKs in the supraspinal neurons and induced axonal regeneration across the transection site, which was confirmed by anterograde labeling with wheat-germ-agglutinin conjugated peroxidase (WGA-HRP). Spinal cord evoked potentials (SCEP) showed that these regenerated axons were electroconductive. Most importantly, CA-MEK virus-treated rats showed significant recovery of hind limb function 2 weeks after operation compared to the control rats treated with no virus or LacZ virus. These results suggest that adenovirus-mediated CA-MEK gene transduction offers a novel strategy for the gene therapy of spinal cord injury.

Induction of VEGF gene transcription by IL-1 beta is mediated through stress-activated MAP kinases and Sp1 sites in cardiac myocytes

Interleukin-1 beta (IL-1 beta) is a multipotent cytokine participating in a variety of cardiovascular diseases. In this study, we examined the effects of IL-1 beta on the expression of vascular endothelial cell growth factor (VEGF) and pursued the molecular mechanisms underlying this effect. Treatment of cultured neonatal rat cardiac myocytes with IL-1 beta increased the levels of VEGF mRNA in a time- and a concentration-dependent manner. These effects were completely abolished by SB203580 and SB202190 (p38 MAPK inhibitors) but not by PD98059 (MEK1 inhibitor), calphostin C (protein kinase C inhibitor), or genistein (tyrosine kinase inhibitor). While IL-1 beta phosphorylated c-Jun N-terminus protein kinase (JNK) rapidly and transiently, the effect of IL-1 beta on p38 mitogen-activated protein kinase (MAPK) was gradual and persistent. Transient transfection assays showed that IL-1 beta increases the transcription from the VEGF promoter. A series of 5;-deletion and site-specific mutation analyses indicated that IL-1 beta as well as overexpression of p38 MAPK and JNK activate VEGF promoter activity through two G+C-rich sequences located at -73 and -62. Electrophoretic mobility shift and supershift assays showed Sp1 and Sp3 proteins specifically bind to the G+C-rich sequences. The half-life of VEGF mRNA was significantly increased in cells treated with IL-1 beta. Together, these results indicate that IL-1 beta induces VEGF gene expression at both transcriptional and post-transcriptional levels, and IL-1 beta evokes p38 MAPK and JNK signalings, which in turn stimulate the transcription of the VEGF gene through Sp1-binding sites. These findings suggest the role of IL-1 beta as a cytokine inducing VEGF in cardiac myocytes, and imply that activation of stress-activated MAP kinases regulate Sp1 sites-dependent transcription.

Lysophosphatidic acid enhances collagen gel contraction by hepatic stellate cells: association with rho-kinase

We studied the effect of lysophosphatidic acid (LPA) on collagen gel contraction by cultured rat hepatic stellate cells (HSCs) in association with the function of Rho-kinase, one of the target molecules of small GTPase Rho. Binding studies showed a single class-binding site of LPA on HSCs. LPA enhanced the contraction of a collagen lattice seeded with HSCs. LPA increased the number of HSCs with polygonal morphology that contained actin stress fibers, and enhanced the phosphorylation of myosin light chain and the assembly of focal adhesion kinase and RhoA around fibronectin-coated beads seeded on HSCs. The electric cell-substrate impedance sensor system showed that LPA enhanced adhesion of HSC to extracellular substrate. All the effects of LPA were suppressed by Y-27632, Rho-kinase inhibitor. These data support the notion that LPA is involved in modulating HSC morphology, its attachment to surrounding extracellular matrix and its contraction by a mechanism involving Rho-kinase.

Folding of green fluorescent protein and the cycle3 mutant

Although the correct folding of green fluorescent protein (GFP) is required for formation of the chromophore, it is known that wild-type GFP cannot mature efficiently in vivo in Escherichia coli at 37 degrees C or higher temperatures that the jellyfish in the Pacific Northwest have never experienced. Recently, by random mutagenesis by the polymerase chain reaction (PCR) method, a mutant called Cycle3 was constructed. This mutant had three mutations, F99S, M153T, and V163A, on or near the surface of the GFP molecule and was able to mature correctly even at 37 degrees C [Crameri et al. (1996) Nat. Biotechnol. 143, 315-319]. In the present study, we investigated the differences in their folding behavior in vitro. We observed the folding and unfolding reactions of both wild-type GFP and the Cycle3 mutant by using green fluorescence as an indicator of the formation of the native structure and examining hydrogen-exchange reactions by Fourier transform infrared spectroscopy. Both proteins showed unusually slow refolding and unfolding rates, and their refolding rates were almost identical under the native state at 25 and at 35 degrees C. On the other hand, aggregation studies in vitro showed that wild-type GFP had a strong tendency to aggregate, while the Cycle3 mutant did not. These results indicated that the ability to mature efficiently in vivo at 37 degrees C was not due to the improved folding and that reduced hydrophobicity on the surface of the Cycle3 mutant was a more critical factor for efficient maturation in vivo.

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

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

Alternate numbness in the upper extremities as the initial symptom of basilar migraine: an electrophysiological evaluation using EEG power topography

A case of basilar migraine (BM) with alternate numbness as the initial symptom is described. The patient's chief complaint was alternate numbness in the right and left upper extremities. After angiography the patient fell into a drowsy state, followed by excitation, and finally confusion. The EEG power topography showed slow alpha, theta and delta power in the right occipital area, and alternatively in the right and left parietal area. These findings suggest that the cause of BM is not only based on a vasoconstriction mechanism, but also cortical spreading depression. BM should be suspected as a cause of sensory symptoms.

Expression of mRNA for axon guidance molecules, such as semaphorin-III, netrins and neurotrophins, in human osteoblasts and osteoclasts

In the present study, we demonstrated the constitutive expression of diffusible axon guidance molecules such as neurotrophins, semaphorin-III, netrin-1, and netrin-2-like protein, which are known to function as a chemoattractant and/or chemorepellent for growing nerve fibers, in human osteoblastic and osteoclastic cells. The findings, obtained by RT-PCR, ELISA, and Western blot analysis suggest the extension of axons of peripheral sensory and sympathetic neurons to osteoblastic and osteoclastic cells and the possible neural regulation of bone metabolism in these osteogenic cells.

Changes in photosynthetic carbon flow in transgenic rice plants that express C4-type phosphoenolpyruvate carboxykinase from Urochloa panicoides

A cDNA encoding phosphoenolpyruvate carboxykinase (PCK) of Urochloa panicoides (a PCK-type C4 plant) was expressed in rice (Oryza sativa cv Tsukinohikari) plants under the control of the promoter of a maize (Zea mays) gene for phosphoenolpyruvate carboxylase or pyruvate, orthophosphate dikinase with the transit peptide of the small subunit of Rubisco. Crude extracts prepared from the green leaves of transgenic plants had high PCK activity and the newly expressed PCK was localized in chloroplasts. In labeling experiments with (14)CO(2) up to 20% of the radioactivity was incorporated into 4C compounds (malate, oxaloacetate, and aspartate) in excised leaves of transgenic plants, as compared with about 1% in excised leaves of control plants. There was a positive correlation between PCK activity and the extent of labeling of 4C compounds. When L-[4-(14)C]malate was fed to excised leaves the extent of incorporation of radioactivity into sucrose was 3-fold greater in transgenic plants than in control plants and the level of radiolabeled aspartate was significantly lower in transgenic plants. These results indicate that the ectopic expression of PCK in rice chloroplasts was able partially to change the carbon flow in mesophyll cells into a C4-like photosynthetic pathway. Such a strategy appears to provide a possible method for enhancing the photosynthetic capacity of C3 plants.

New type of starch-binding domain: the direct repeat motif in the C-terminal region of Bacillus sp. no. 195 alpha-amylase contributes to starch binding and raw starch degrading

The alpha-amylase from Bacillus sp. no. 195 (BAA) consists of two domains: one is the catalytic domain similar to alpha-amylases from animals and Streptomyces in the N-terminal region; the other is the functionally unknown domain composed of an approx. 90-residue direct repeat in the C-terminal region. The gene coding for BAA was expressed in Streptomyces lividans TK24. Three active forms of the gene products were found. The pH and thermal profiles of BAAs, and their catalytic activities for p-nitrophenyl maltopentaoside and soluble starch, showed almost the same behaviours. The largest, 69 kDa, form (BAA-alpha) was of the same molecular mass as that of the mature protein estimated from the nucleotide sequence, and had raw-starch-binding and -degrading abilities. The second largest, 60 kDa, form (BAA-beta), whose molecular mass was the same as that of the natural enzyme from Bacillus sp. no. 195, was generated by proteolytic processing between the two repeat sequences in the C-terminal region, and had lower activities for raw starch binding and degrading than those of BAA-alpha. The smallest, 50 kDa, form (BAA-gamma) contained only the N-terminal catalytic domain as a result of removal of the C-terminal repeat sequence, which led to loss of binding and degradation of insoluble starches. Thus the starch adsorption capacity and raw-starch-degrading activity of BAAs depends on the existence of the repeat sequence in the C-terminal region. BAA-alpha was specifically adsorbed on starch or dextran (alpha-1,4 or alpha-1,6 glucan), and specifically desorbed with maltose or beta-cyclodextrin. These observations indicated that the repeat sequence of the enzyme was functional in the starch-binding domain (SBD). We propose the designation of the homologues to the SBD of glucoamylase from Aspergillus niger as family I SBDs, the homologues to that of glucoamylase from Rhizopus oryzae as family II, and the homologues of this repeat sequence of BAA as family III.

[Sudden bilateral hearing loss with vertigo due to vertebral artery occlusion]

We report a case of sudden bilateral hearing loss associated with an occlusion of the right vertebral artery. A 66-year-old man was admitted to hospital suffering from sudden onset vertigo, deafness, and vomiting. He could not walk due to truncal ataxia. There was positional nystagmus to the right; spontaneous and gaze-evoked nystagmus were absent. He had no facial nerve palsy, dysarthria, pyramidal tract signs, limb ataxia, and sensory impairment. Pure tone audiometry demonstrated a profound sensorineural deafness of both ears. A tentative diagnosis of sudden deafness was made. He was treated with intravenous infusion of corticosteroid; hearing loss of the left ear slightly improved. Cranial MR imaging demonstrated fresh small infarcts in the right cerebellar tonsil, the left cerebellar medulla, and the left middle cerebellar peduncle. MR angiography demonstrated an occlusion of the right vertebral artery. It is possible that reduced perfusion of the anterior inferior cerebellar arteries and internal auditory arteries on both sides resulted in multiple "border zone" infarcts and damage to the inner ear. Clinicians should be aware of the possibility of vertebrobasilar occlusive disease in case of sudden bilateral hearing impairment, even when brainstem or cerebellar signs are absent.

Intracranial aneurysms and autosomal dominant polycystic kidney disease: followup study by magnetic resonance angiography

PURPOSE

Intracranial aneurysms are known to complicate autosomal dominant polycystic kidney disease. We assess the value of magnetic resonance angiography to detect intracranial aneurysms early in patients with autosomal dominant polycystic kidney disease.

MATERIALS AND METHODS

We evaluated 15 patients with asymptomatic autosomal dominant polycystic kidney disease treated at our hospital between 1992 and 1998. Magnetic resonance angiography was performed at presentation and was repeated 18 to 72 months after treatment.

RESULTS

On the initial magnetic resonance angiogram 3 intracranial aneurysms were detected in 3 patients. The intracranial aneurysms ranged from 4 to 8 mm. in diameter, and were in the anterior communicating artery in 1, in the vertebral artery in 1, and at the bifurcation of the internal carotid artery and ophthalmic artery in 1 case. Repeat magnetic resonance angiography 18 to 72 months after treatment revealed new intracranial aneurysms in 2 patients. In 1 case the lesion was 7 mm. in diameter, in the internal carotid artery and posterior communicating artery, and detected 69 months after the initial angiogram. In the other patient the lesion was 4 mm. in diameter, in the anterior communicating artery and detected 71 months after treatment.

CONCLUSIONS

Since new intracranial aneurysms were demonstrated in patients followed for a long time periodic repeat magnetic resonance angiography is important.

Uterine leiomyoma causing massive ascites and left pleural effusion with elevated CA 125: a case report

A 51-year-old patient presented with an abdominal mass and ascites as well as a left pleural effusion. Her serum CA125 was 820 U/ml. Surgical exploration revealed a benign leiomyoma of the uterus without malignant cytology in the ascites. Postoperatively, the pleural effusion was resolved dramatically and the CA125 decreased to the normal range after 4 months post-operatively. This is an extremely rare case of pseudo-Meigs' syndrome caused by uterine leiomyoma.

Contribution of adenosine A(2) receptors and cyclic adenosine monophosphate to protective ischemic preconditioning of sinusoidal endothelial cells against Storage/Reperfusion injury in rat livers

A brief period of liver ischemia decreases sinusoidal endothelial cell killing after cold liver storage and improves graft survival after liver transplantation, a phenomenon called ischemic preconditioning. In this study, we investigated the mechanism of sinusoidal endothelial cell protection after ischemic preconditioning. Livers were preconditioned by 5 minutes of ischemia and 5 minutes of reperfusion. Subsequently, livers were stored for 30 hours in cold University of Wisconsin (UW) solution and reperfused briefly with physiological buffer containing Trypan blue. Ischemic preconditioning decreased sinusoidal endothelial cell killing after storage/reperfusion, as assessed by Trypan blue staining of nonparenchymal cells. Adenosine A(2) receptor blockade prevented the protective effect of ischemic preconditioning. By contrast, adenosine A(1) receptor blockade did not prevent protective ischemic preconditioning. Other rat livers were treated with adenosine A(1) and A(2) receptor agonists or dibutyryl-cyclic adenosine monophosphate (DB-cAMP) before storage. The adenosine A(2) receptor agonist, CGS-21680, and DB-cAMP decreased sinusoidal endothelial cell killing to the same extent as ischemic preconditioning, but the adenosine A(1) receptor agonist, 2-chloro-N(6)-cyclopentyladenosine (CCPA), had no effect. The adenosine A(2) agonist and prostaglandin E(2), another agent that preconditions sinusoidal endothelial cells against storage/reperfusion injury, but not the adenosine A(1) agonist, increased cAMP levels in cultured sinusoidal endothelial cells. In conclusion, an adenosine A(2) receptor pathway coupled to increased cAMP mediates sinusoidal endothelial cell protection by ischemic preconditioning.

Unclassified connective tissue disease presenting as cardiac tamponade: a case report

This report describes a case of cardiac tamponade as the initial manifestation of unclassified connective tissue disease (UCTD). A 68-year-old Japanese woman was admitted to hospital because of dyspnea and edema. She had undergone a radical left mastectomy for the treatment of breast cancer 18 years before. On admission, bilateral leg edema, hepatomegaly, and a paradoxical pulse were noted on physical examination. The erythrocyte sedimentation rate was elevated and the C-reactive protein was 2.8 mg/dl. Antinuclear antibodies and anti-SS-A/Ro antibodies were present. The scl-70 and anticentromere antibodies were elevated. Chest radiography showed cardiomegaly. Echocardiography revealed a large pericardial effusion, but the pericardial fluid did not contain malignant cells or bacteria. She did not meet the diagnostic criteria for any known connective tissue diseases, so was diagnosed with cardiac tamponade due to UCTD. Prednisolone (30 mg/day) was administered, which resulted in a gradual resolution of the pericardial effusion. Although connective tissue diseases are known to cause pericardial effusion, cardiac tamponade as the initial manifestation of the disease in the absence of other symptoms is quite rare.

Gene expression of interstitial collagenase in both progressive and recovery phase of rat liver fibrosis induced by carbon tetrachloride

BACKGROUND/AIMS

Liver fibrosis is a dynamic state between matrix production and degradation. Since our report in 1974, many studies have examined collagenase and liver fibrosis, but not the identification of cells responsible for collagenase production in vivo. The aim of this study was to investigate the gene expression of interstitial collagenase in the progressive and recovery phases of experimental rat liver fibrosis by in situ hybridization.

METHODS

We examined the gene expression of interstitial collagenase (MMP-13) in the progressive and recovery phase of experimental rat liver fibrosis induced by chronic CCl4 intoxication by reverse transcription-polymerase chain reaction (RT-PCR) and in situ hybridization. In order to identify the cells expressing MMP-13 mRNA by in situ hybridization, immunohistochemistry was performed using serial sections.

RESULTS

In normal rat liver, a faint band for MMP-13 mRNA was observed by RT-PCR, but not by in situ hybridization. The livers of rats treated with CCl4 for 4 weeks showed fatty metamorphosis but no definite fibrosis. Positive signals for MMP-13 mRNA were observed in scattered mesenchymal cells, within lobules which seem to be stellate cells from immunohistochemical staining. Once the fibrosis became prominent, the faint band for MMP-13 mRNA was detected only by RT-PCR and very few signals, if any, by in situ hybridization. On the other hand, in the recovery phase of liver fibrosis, gene expression of MMP-13 was markedly enhanced. Strong positive cells by in situ hybridization were observed mainly at the interface between the resolving fibrous septa and the parenchyma. Overlapping both images of in situ hybridization and immunohistochemical staining with the help of a computer revealed that some positive cells, but not all cells, were stellate cells stained with a-smooth muscle actin antibody.

CONCLUSIONS

MMP-13 participates in the degradation of newly-formed matrix in the recovery from rat liver fibrosis more than in the remodeling of extracellular matrix for the formation of fibrosis. Hepatic stellate cells play a crucial role in MMP-13 production in the recovery from fibrosis, though not all stellate cells were positive for MMP-13 mRNA. Further investigation into gene expression of MMP-13 in recovery will lead to new strategies for the treatment of liver cirrhosis.

Pattern reversal visual evoked response in retinitis pigmentosa

PURPOSE

To determine if the pattern reversal visual evoked response (PVER) can objectively evaluate visual function in retinitis pigmentosa (RP).

METHODS

We retrospectively reviewed the medical records of 29 patients (29 eyes) with RP, a visual acuity (VA) better than 20/100, and for whom an electroretinogram (ERG) and a PVER had been recorded. A steady-state PVER was measured using five check sizes: 160, 80, 40, 20 and 10 min of arc. The best-corrected VA was measured using the ETDRS chart. Visual fields (VFs) were measured using standard Goldmann perimetry. To quantify the VFs, we measured the field size (isopter IV-2) in four meridians and averaged them. Twenty-five eyes of 25 normal subjects served as controls.

RESULTS

The mean and median VAs were 20/40 (logMAR = 0.30 +/- 0.20). The average VF (isopter IV-2 ) was 20 degrees (median, 9 degrees: range. 2 degrees to 62 degrees). All patients had a recordable PVER. Only 12 (41 %) patients had a recordable ERGs, all subnormal. The PVER amplitudes showed a relatively good correlation with VA in the intermediate check sizes (40 min of arc, r = 0.611. P = 0.0004: 20 min of arc, r = 0.596. P = 0.0007). The PVER amplitude-check size function had a flattened inverted V shape in the RP patients and an inverted U shape in the normal subjects, with the mean amplitudes for the RP patients significantly smaller than the normals at all check sizes.

CONCLUSION

The PVER is a useful method for objectively evaluating the visual function in RP patients whose central vision is still preserved.

Cardiac ankyrin repeat protein is a novel marker of cardiac hypertrophy: role of M-CAT element within the promoter

CARP, a cardiac doxorubicin (adriamycin)-responsive protein, has been identified as a nuclear protein whose expression is downregulated in response to doxorubicin. In the present study, we tested the hypothesis that CARP serves as a reliable genetic marker of cardiac hypertrophy in vivo and in vitro. CARP expression was markedly increased in 3 distinct models of cardiac hypertrophy in rats: constriction of abdominal aorta, spontaneously hypertensive rats, and Dahl salt-sensitive rats. In addition, we found that CARP mRNA levels correlate very strongly with the brain natriuretic peptide mRNA levels in Dahl rats. Transient transfection assays into primary cultures of neonatal rat cardiac myocytes indicate that transcription from the CARP and brain natriuretic peptide promoters is stimulated by overexpression of p38 and Rac1, components of the stress-activated mitogen-activated protein kinase pathways. Mutation analysis and electrophoretic mobility shift assays indicated that the M-CAT element can serve as a binding site for nuclear factors, and this element is important for the induction of CARP promoter activity by p38 and Rac1. Thus, our data suggest that M-CAT element is responsible for the regulation of the CARP gene in response to the activation of stress-responsive mitogen-activated protein kinase pathways. Moreover, given that activation of these pathways is associated with cardiac hypertrophy, we propose that CARP represents a novel genetic marker of cardiac hypertrophy.

Comparison of spinal cord evoked potentials and peripheral nerve evoked potentials by electric stimulation of the spinal cord under acute spinal cord compression in cats

STUDY DESIGN

Spinal cord evoked potentials and peripheral nerve evoked potentials after spinal cord stimulation were recorded under acute spinal cord compression in 19 cats.

OBJECTIVES

To investigate the effects of acute compression upon grey matter and white matter by comparing both potentials.

METHODS

We compared peripheral nerve evoked potentials, recorded at the biceps brachii branch of the musculocutaneous nerve, with descending spinal cord evoked potentials, recorded from the lumbar spinal cord, by stimulation to the C2 level, under compression of the C6 segment.

RESULTS

The amplitude of both potentials decreased with increased compression. The second wave of peripheral nerve evoked potentials, which are motor fibre action potentials, decreased sooner than those of the spinal cord evoked potentials.

CONCLUSION

These findings indicate that peripheral nerve evoked potentials are sensitive to acute damage of the segmented compression. This suggests that grey matter is more vulnerable to compression than white matter.

Identification and characterization of differentially expressed mRNAs in HIV type 1-infected human T cells

We used a novel differential display (DD) technique to identify host factors involved in virus replication, pathogenesis, and host response in HIV-1-infected T cells. Thirteen cDNA fragments differentially expressed in HIV-1NL4-3-infected MT-4 cells prior to the occurrence of specific apoptotic cell death were sequenced and identified. Two of seven elevated genes were identical to HIV-1 sequences and the other five were MIP-1alpha, ACTE-III, CD11c, arginase I, and CCR5. The six downregulated genes included prothymosin-a, Jaw-1, proteasome subunit XAPC7, splicing factor 9G8, GA17 protein, and an unknown mRNA. Northern blot and RT-PCR analyses confirmed the altered gene expressions in MT-4 cells as well as in another T cell line, MOLT-4. We also revealed that the amount of MIP-1alpha in culture supernatant of HIV-1-infected cells was increased by more than 15-fold relative to control cells, and the expression of its receptor CCR5 was cooperatively upregulated on the surface of these cells. Furthermore, the upregulation of CD11c after HIV-1 infection was slightly inhibited by blocking the MIP-1alpha-mediated signal transduction. These results indicate that genes altered on HIV-1 infection may be mutually organized and play an important role in HIV-1-induced pathogenesis.

Interleukin-18 in patients with congestive heart failure: induction of atrial natriuretic peptide gene expression

Activated inflammatory responses appear to play a role in the development of congestive heart failure (CHF). We investigated interleukin-18 (IL-18), which is a cytokine synthesized by activated macrophage, changes in patients with CHF. We evaluated 11 Japanese patients with angina pectoris (n=4) or CHF (n=7). Blood was sampled immediately after admission and at 1, 2, 3, 6, and 9 hours after admission and then every 12 hours until 5 days after admission. Plasma IL-18 concentrations were measured by an enzyme-linked immunosorbent assay. Expression of atrial natriuretic peptide (ANP) mRNA and protein synthesis was examined in cardiac myocyte by stimulation of IL-18. Plasma IL-18 concentration was significantly higher in patients with CHF than in 15 healthy volunteers (51+/-21 pg/mL, and 28+11 pg/mL, respectively, P<0.05). Increased expression of ANP mRNA was demonstrated in IL-18 treated myocytes. Protein synthesis in myocytes was increased by IL-18 in a dose-dependent manner. Increased secretion of IL-18 is induced in patients with CHF and correlates with the severity of myocardial damage and dysfunction.

Cloning and sequencing of an endoglucanase gene from Scopulariopsis brevicaulis TOF-1212, and its expression in Saccharomyces cerevisiae

The egI gene, encoding a major endoglucanase (EGI) of Scopulariopsis brevicaulis TOF-1212, was cloned and sequenced. The eglgene consisted of 868 bp with one intron and encoded a protein of 229 amino acids with a calculated molecular mass of 22,392 daltons. The EGI was assigned to a family 45 of glycosyl hydrolases and showed high similarity with other fungal endoglucanases, especially with those of Humicola grisea and Fusarium oxysporum, on the basis of hydrophobic cluster analysis. The egI gene was expressed under the promoter of the phosphoglycerate kinase gene (PGK) in Saccharomyces cerevisiae. The transformed cells were able to secrete the enzyme efficiently in an active form.

Enantioselective binding of propranolol, disopyramide, and verapamil to human alpha(1)-acid glycoprotein

We investigated the binding of propranolol (PL), disopyramide (DP), and verapamil (VP) enantiomers by human alpha(1)-acid glycoprotein (AGP; also called orosomucoid) and the relationships between the extent of drug binding and lipophilicity, desialylation, and genetic variants of AGP. Desialylation had little effect on the affinity of AGP for the drugs tested. The percentage binding correlated significantly with the partition coefficients for the drugs tested. Each enantiomer was competitively displaced from AGP by another enantiomer of the same drug, suggesting that they bind to the same site. However, the enantiomers bound to AGP with stereospecific affinities; the (-)-isomers of DP and VP had higher Kd values (4.27 and 4.97 microM, respectively) than the (+)-isomers (1.51 and 2.48 microM, respectively). When enantiomers of the different drugs were used in competitive binding experiments, VP binding was only partially inhibited by DP. This result suggested that drug binding is specific to different variants of AGP (A, F1, S). DP was found to specifically bind to variant A, whereas PL and VP bind to both A and F1/S variants.

Influence of cetane improvers on the air quality in an urban street canyon

The concentration distributions of NOx, PM, HC and CO in an urban street canyon have been estimated using a two-dimensional air quality numerical model based on the k-epsilon turbulent model and the atmospheric convection diffusion equation when various cetane improvers were used in diesel fuels. A wind vortex can be found within the street canyon, and the pollutants emitted from the bottom of the street canyon tend to follow the course of the wind field, moving circularly. The addition of cetane improvers can improve the air quality in a street canyon, all of the pollutants were found to decrease with increasing centane number.

Cell type-specific E2F activation and cell cycle progression induced by the oncogene product Tax of human T-cell leukemia virus type I

The transactivator protein Tax of human T-cell leukemia virus type I plays an important role in the development of adult T-cell leukemia probably through modulation of growth regulatory molecules including p16(INK4a). The molecular mechanism of leukemogenesis induced by Tax has yet to be elucidated. We analyzed Tax function in the cell cycle using an interleukin-2 (IL-2)-dependent human T-cell line (Kit 225) that can undergo cell cycle arrest at G(0)/G(1) phase by deprivation of IL-2. Tax activated endogenous E2F activity in IL-2-starved Kit 225 cells, resulting in activation of E2F site-carrying promoters of genes involved in G(1) to S phase transition in a cell type-dependent and p16(INK4a)-independent manner. The ability of Tax mutants to activate E2F coincided with that to activate nuclear factors kappaB and AT, sole expression of which, however, did not activate E2F, suggesting involvement of another pathway in activation of E2F. Introduction of Tax by a recombinant adenovirus induced cell cycle progression to G(2)/M phase in resting Kit 225 cells accompanied by endogenous cyclin D2 gene expression. Similarly, Tax-induced cell cycle progression was seen with peripheral blood lymphocytes prestimulated with phytohemagglutinin. Analyses with Tax mutants did not allow Tax-induced cell cycle progression to be differentiated from Tax-dependent activation of E2F, suggesting that Tax induces cell cycle progression presumably through activation of E2F. Nevertheless, infection with an E2F1-expressing virus, which is sufficient for induction of S phase in serum-starved fibroblasts, was not sufficient for either E2F activation or cell cycle progression in IL-2-starved Kit 225 cells, implying differential regulation of E2F activation and cell cycle progression in T-cells that is activated by Tax.

Ruptured cerebral aneurysm not detected by magnetic resonance angiography in juvenile autosomal dominant polycystic kidney

Recently, it has been reported that magnetic resonance angiography (MRA) is useful for screening and following up cerebral aneurysms in patients with autosomal dominant polycystic kidney disease (ADPKD). However, a patient was encountered with a ruptured cerebral aneurysm that was not detected by routine MRA. The patient, a 29-year-old man with ADPKD, was followed up at our hospital for more than 5 years. Ten months after an MRA examination, he suddenly developed severe headache. Brain computed tomography revealed subarachnoid hemorrhage. Digital subtraction angiography detected an aneurysm with a diameter of approximately 2 mm in the anterior communicating artery. Clipping of the aneurysm was immediately performed and he recovered without sequela after operation. Magnetic resonance angiography is useful to detect cerebral aneurysms, but it can not detect aneurysms measuring less than 4 mm.

Effect of an alternative disulfide bond on the structure, stability, and folding of human lysozyme

Human lysozyme has four disulfide bonds, one of which, Cys65-Cys81, is included in a long loop of the beta-domain. A cysteine-scanning mutagenesis in which the position of Cys65 was shifted within a continuous segment from positions 61 to 67, with fixed Cys81, has previously shown that only the mutant W64CC65A, which has a nonnative Cys64-Cys81 disulfide, can be correctly folded and secreted by yeast. Here, using the W64CC65A mutant, we investigated the effects of an alternative disulfide bond on the structure, stability, and folding of human lysozyme using circular dichroism (CD) and fluorescence spectroscopy combined with a stopped-flow technique. Although the mutant is expected to have a different main-chain structure from that of the wild-type protein around the loop region, far- and near-UV CD spectra show that the native state of the mutant has tightly packed side chains and secondary structure similar to that of the wild-type. Guanidine hydrochloride-induced equilibrium unfolding transition of the mutant is reversible, showing high stability and cooperativity of folding. In the kinetic folding reaction, both proteins accumulate a similar burst-phase intermediate having pronounced secondary structure within the dead time of the measurement and fold into the native structure by means of a similar folding mechanism. Both the kinetic refolding and unfolding reactions of the mutant protein are faster than those of the wild-type, but the increase in the unfolding rate is larger than that of the refolding rate. The Gibbs' free-energy diagrams obtained from the kinetic analysis suggest that the structure around the loop region in the beta-domain of human lysozyme is formed after the transition state of folding, and thus, the effect of the alternative disulfide bond on the structure, stability, and folding of human lysozyme appears mainly in the native state.

Is folding of beta-lactoglobulin non-hierarchic? Intermediate with native-like beta-sheet and non-native alpha-helix

The refolding of beta-lactoglobulin, a beta-barrel protein consisting of beta strands betaA-betaI and one major helix, is unusual because non-native alpha-helices are formed at the beginning of the process. We studied the refolding kinetics of bovine beta-lactoglobulin A at pH 3 using the stopped-flow circular dichroism and manual H/(2)H exchange pulse labeling coupled with heteronuclear NMR. The protection pattern from the H/(2)H exchange of the native state indicated the presence of a stable hydrophobic core consisting of betaF, betaG and betaH strands. The protection pattern of the kinetic intermediate obtained about one second after initiating the reaction was compared with that of the native state. In this relatively late kinetic intermediate, which still contains some non-native helical structure, the disulfide-bonded beta-hairpin made up of betaG and betaH strands was formed, but the rest of the molecule was fluctuating, where the non-native alpha-helices may reside. Subsequently, the core beta-sheet extends, accompanied by a further alpha-helix to beta-sheet transition. Thus, the refolding of beta-lactoglobulin exhibits two elements: the critical role of the core beta-sheet is consistent with the hierarchic mechanism, whereas the alpha-helix to beta-sheet transition suggests the non-hierarchic mechanism.

Heck reactions of iodobenzene and methyl acrylate with conventional supported palladium catalysts in the presence of organic and/or inorganic bases without ligands

The vinylation of iodobenzene with methyl acrylate has been studied with several supported palladium catalysts in N-methylpyrrolidone in the presence of triethylamine and/or sodium carbonate. The reaction can be performed in air without any solubilizing or activating ligands. It was found that significant amounts of palladium leach out into the solvent and these dissolved Pd species essentially catalyze the reaction. It is interesting, however, that almost all the palladium species in the solution can redeposit onto the surface of the supports after the reaction has been completed (at 100% conversion of iodobenzene). Thus, the catalysts were recyclable without loss of activity. The use of both inorganic and organic bases is very effective in the promotion of the palladium redeposition as well as in the enhancement of the reaction rate. For Heck reactions with bromobenzene and chlorobenzene it was found that the use of triethylamine and sodium carbonate increases the selectivity of the Heck coupling product (benzene is also produced for these two substrates), but the mixed bases do not affect the overall rate of reaction as much.

T-0162, a novel free radical scavenger, reduces myocardial infarct size in rabbits

1. We investigated the effects of 1-(3-tert-butyl-2-hydroxy-5-methoxyphenyl)-3-(3-pyridylmethyl)urea hydrochloride (T-0162), a novel low-molecular weight free radical scavenger, on the generation of superoxide anions and hydroxyl radicals in vitro and in vivo and on myocardial infarct (MI) size in an in vivo model of MI in rabbits. 2. It was found that T-0162 scavenged both superoxide anions and hydroxyl radicals in a concentration-dependent manner in vitro. 3. In an in vivo rabbit model with 30 min coronary occlusion and 30min reperfusion, T-0162 scavenged hydroxyl radicals generated in the myocardium during reperfusion. 4. Anaesthetized open-chest Japanese white male rabbits were subjected to 30 min coronary occlusion and 48 h reperfusion. The control group (n = 10) was infused with 10% lecithin solution for 220 min from 10 min before occlusion to 180 min after reperfusion. The pretreatment group (n = 10) was infused with T-0162 dissolved in 10% lecithin solution for 220 min from 10 min before occlusion to 180 min after reperfusion at a rate of 400 microg/kg per min. The post-treatment group (n = 10) was injected with an i.v. bolus of 10 mg/kg T-0162 and was then infused with 400 microg/kg per min T-0162 for 190 min from 10 min before reperfusion to 180 min after reperfusion. After 48 h reperfusion, infarct size was measured histologically and expressed as a percentage of area at risk (AAR). 5. There was no significant difference in haemodynamic parameters among the three groups throughout the experimental period. The per cent infarct size of the AAR in the T-0162 groups (24.8+/-4.3 and 30.5+/-3.9% for pre- and posttreatment groups, respectively) was significantly reduced compared with control (44.7+/-4.1%; P<0.05). There was no significant difference in the AAR among the three groups. 6. In conclusion, T-0162 reduces MI size through the inhibition of reperfusion injury.

Molecular mechanism of the reversibility of hepatic fibrosis: with special reference to the role of matrix metalloproteinases

The participation of matrix metalloproteinases (MMP) and their specific inhibitors, the tissue inhibitors of matrix metalloproteinases (TIMP), in both the formation and degradative recovery processes of liver fibrosis were mainly reviewed from the molecular biological aspect. Since authors first reported increased activity of interstitial collagenase in the early stage of hepatic fibrosis in rats induced by chronic CCl4 intoxication, in baboons fed alcohol chronically and in patients with alcoholic fibrosis, other investigators have also demonstrated increased activity biologically and histochemically. However, species-specific differences in response have been found and gene-level research on the rat model has not demonstrated increased mRNA transcription of collagenase. It has also been clarified that activated stellate cells can also produce matrix components. Very recently, authors observed the participation of interstitial collagenase in the recovery from experimental hepatic fibrosis by using polymerase chain reaction northern blotting and in situ hybridization. The in situ hybridization findings not only demonstrated the cells responsible for interstitial collagenase, but also suggested a great deal about the mechanism of recovery from fibrosis. Hepatic stellate cells are activated via the expression of c-myb and nuclear factor-kappaB (NFkappaB) which is induced by oxidative stress, and inhibited by antioxidant (1-alpha-tocopherol) and butylated hydroxytoluene. The activation mechanism is now being revealed. The relationship between the activation mechanism of stellate cells and the production and secretion of MMP and TIMP in the formation and recovery process of hepatic fibrosis should be investigated from the promoter gene level. This approach might help develop a new strategy for the treatment of liver fibrosis.

[Quantitation of human immunodeficiency virus type 1 RNA by ultrasensitive method in the analysis of samples with low viral load]

With the introduction of combination therapy to the patients with Human Immunodeficiency Virus Type 1(HIV-1) infection, HIV-1 RNA levels in plasma have been reduced, frequently to less than limit of quantitation(400 copies/ml). To achieve enhanced sensitivity, a modified specimen preparation procedure that allows the quantitation of plasma HIV-1 RNA levels as low as 50 copies/ml was developed. Of 67 samples with less than 400 copies/ml of HIV-1 RNA by standard method, 39(58.2%) were not detected by the "ultrasensitive" method. Among 5 samples obtained from patients who were treated with 2 nucleoside reverse transcriptase inhibitors, 4 samples still had detectable copies of HIV-1 RNA. Those suggest that the ultrasensitive assay for HIV-1 RNA has advantage for clinical practice.

Zinc finger transcription factor Egr-1 activates Flt-1 gene expression in THP-1 cells on induction for macrophage differentiation

Activation of macrophages is a hallmark of atherosclerosis. Stimulation of human monocytic leukemia THP-1 cells with phorbol 12-myristate 13-acetate (PMA) is known to induce a variety of genes whose function is relevant to activated macrophages. Flt-1, a receptor tyrosine kinase for vascular endothelial growth factor, is expressed in macrophages as well as in endothelial cells and mediates the biological response to vascular endothelial growth factor. In this study, we investigated the molecular mechanisms underlying the inducible expression of the flt-1 gene during the activation of THP-1 cells. Reverse transcription-polymerase chain reaction analysis showed that exposure of THP-1 cells to PMA increases flt-1 mRNA and protein levels. A transfected reporter gene, consisting of the human flt-1 promoter region coupled to the luciferase gene, indicated a direct effect of PMA on transcriptional activity. Transfection analysis of a series of 5'-deletion constructs and site-directed mutants localized the PMA-responsive region to a DNA stretch from -174 to -166, which represents overlapping Egr-1/Sp1 transcription factor-binding sites. Competitive gel mobility shift assays and supershift assays showed that PMA induces the binding of Egr-1 to this site. Consistent with these findings, the Egr-1 expression plasmid strongly induced flt-1 promoter activity in a sequence-specific manner. Taken together, our data demonstrate that PMA induces flt-1 gene transcription through an induction of Egr-1 in THP-1 cells, thus providing new evidence that the flt-1 gene is a direct target of Egr-1, the transcription factor primarily induced on macrophage differentiation.

Three minute, but not one minute, ischemia and nicorandil have a preconditioning effect in patients with coronary artery disease

OBJECTIVES

This study focused on 1) the determination of the optimal preconditioning (PC) duration, and 2) the protective effect of nicorandil (NC), a hybrid nitrate with a KATP channel opening effect, during a percutaneous transluminal coronary angioplasty (PTCA) model in humans.

BACKGROUND

The ischemic PC effect is induced in 180 s ischemia, but not in 120 s ischemia in rabbit hearts. However, the duration of ischemia that induces PC effect and the role of the KATP channel in the PC effect in humans are still unclear.

METHODS

Forty-six patients with stable angina were randomly allocated to four groups: the duration of the first inflation as PC ischemia was 60 s in the PC60 group (n = 12), and 180 s in the PC180 group (n = 12). In the other groups, NC (80 microg/kg) was intravenously given for 1 min in the NC group (n = 12), and isosorbide dinitrate (ISDN) (40 microg/kg) was given in the ISDN group (n = 10). Five minutes after first inflation or drug administration, a second inflation was conducted for 120 s in each group. In the ECG, the lead with the largest shift in ST segment (deltaST max), and the sum of elevated ST levels in all leads (sigmaST) were determined.

RESULTS

In the PC60 group, no significant difference was observed in either deltaST max or sigmaST between the first and second inflation. However, the second inflation in the PC180 group showed significantly lower levels of deltaST max and sigmaST compared with those of the first inflation. In the NC group, both deltaST max and sigmaST measured at 30 s and 60 s after balloon inflation were significantly lower than those of the first inflation in the PC60 and PC180 control groups. In the ISDN group, no significant difference was observed in deltaST max or sigmaST.

CONCLUSION

In human PTCA models, a PC effect is observed in 180 s ischemia, but not in 60 s ischemia. A pharmacological PC effect is induced by NC, a KATP channel opener with a nitrate-like effect but not ISDN. This suggests that the opening of KATP channels plays an important role in the protecting effect of NC.

Antithrombotic activity of avian crown dermatan sulfate

The antithrombotic activity of dermatan sulfate from avian crown with the mean molecular weight of 38000 was compared to those from bovine intestine with the mean molecular weight of 16000 in vivo and in vitro. In an in vitro test, bovine intestine dermatan sulfate exhibited stronger effects on stimulation of heparin cofactor II and activation of Glu-plasminogen by tissue plasminogen activator. In vivo, avian crown dermatan sulfate more effectively prevented the development of thrombus in a rat deep vein thrombosis model. The measurement of plasma levels of these two kinds of dermatan sulfate revealed that avian crown dermatan sulfate circulated in higher concentration and longer duration than bovine intestine dermatan sulfate after intravenous administration to rats.

Mechanism of doxorubicin-induced inhibition of sarcoplasmic reticulum Ca(2+)-ATPase gene transcription

Doxorubicin (DOX)-induced cardiomyopathy has been found to be associated with impaired Ca(2+) handling in the sarcoplasmic reticulum (SR), leading to reduced cardiac function. We have recently demonstrated that expression of mRNA encoding sarco(endo)plasmic reticulum Ca(2+)-ATPase 2 (SERCA2), a major Ca(2+) transport protein in SR, is markedly decreased in DOX-treated hearts. To extend this observation, we have dissected the molecular mechanisms by which DOX downregulates SERCA2 gene transcription. Using cultured rat neonatal cardiac myocytes, we found that the antioxidant N-acetylcysteine blocked the DOX-induced decrease in SERCA2 mRNA levels, as well as the DOX-induced increase in H(2)O(2) concentration; thus, H(2)O(2) is an intracellular mediator of DOX activity. Using a luciferase reporter assay, we found that the sequence from -284 to -72 bp in the 5' flanking region of the SERCA2 gene has a DOX-responsive element. Although several transcription factors have putative binding motifs in this region of the SERCA2 gene, only the expression of Egr-1 mRNA and the binding of Egr-1 protein to the 5' regulatory sequence of SERCA2 gene increased markedly after DOX administration. We also found that overexpression of Egr-1 was associated with a significant reduction in SERCA2 gene transcription. In addition, Egr-1 antisense oligonucleotides blocked the DOX-induced reduction in SERCA2 mRNA, suggesting that Egr-1 is a transcriptional inhibitor of the SERCA2 gene in DOX-induced cardiomyopathy. We observed activation of 3 mitogen-activated protein kinases (MAPKs), p44/42 MAPK, p38 MAPK, and stress-activated MAPK/Jun N-terminal kinase, by DOX, but only a specific inhibitor of the p44/42 MAPK kinase suppressed the effects of DOX on Egr-1 and SERCA2 mRNA expression. These findings indicate that reactive oxygen intermediates, the transcription factor Egr-1, and p44/42 MAPK are critical elements in the transcriptional regulation of the SERCA2 gene in response to DOX.

Therapy with the nonpeptide endothelin receptor antagonist 97-139 in a murine model of congestive heart failure: reduction of cardiac mass and myofiber hypertrophy

Endothelin-1 (ET-1) is a potent vasoconstrictor. This peptide exerts numerous effects on the heart, including regulation of cardiomyocyte growth during hypertrophy. The effects of the structurally novel, nonpeptide, ET-1-selective, competitive antagonist (ETA) 97-139 were investigated in mice with congestive heart failure (CHF) and myocardial hypertrophy. Morphological and microscopical analyses were conducted on day 56 after viral inoculation following 28 day treatment with 99-139. Eight week-old DBA2 mice were intraperitoneally inoculated with encephalomyocarditis virus at a dose of 500 pfu/mouse. The 30 mice were divided into two groups--an ETA treated group and an untreated group. Heart weight (HW) in the infected group was significantly (p < 0.05) increased compared to that in the uninfected group. HW and the HW/body weight (BW) ratio were significantly (p < 0.05) reduced in the ETA treated group compared with the untreated group (HW; 127.7 +/- 6.2 mg vs 144.3 +/- 4.2 mg, HW/BW; 4.9 +/- 0.9 x 10(-3) vs 5.4 +/- 0.5 x 10(-3)). Myofiber diameter in the ETA treated group was significantly reduced compared with the untreated group (12.1 +/- 1.5 microm vs 14.3 +/- 1.9 microm). These results suggest the ET-1 receptor antagonist 97-139 has an effect on the reduction of cardiac mass and myofiber hypertrophy, and that 97-139 may be a useful agent for CHF due to viral myocarditis.

Function and regulation of sarcoplasmic reticulum Ca2+-ATPase: advances during the past decade and prospects for the coming decade

In cardiac muscle, the contraction-relaxation cycle is tightly controlled by the regulated release and uptake of intracellular Ca2+ between sarcoplasmic reticulum and cytoplasm. A major protein controlling Ca2+ cycling is Ca2+-ATPase (SERCA2a) located in the sarcoplasmic reticulum membrane. The function of SERCA2a protein is regulated by the phosphorylatable protein, phospholamban. Phosphorylation of phospholamban releases its inhibitory effect on SERCA2a through direct molecular interaction. Recently, mice whose SERCA2a function is increased (overexpression of the gene) or lost (knock out) were developed. These mice demonstrated that SERCA2a pump levels are a major determinant of cardiac muscle contractility and relaxation. These studies open the prospect that the overexpression of SERCA2a can correct cardiac dysfunction seen in heart failure. Advances in knowledge concerning the function and gene regulation of SERCA2a are discussed in this review.

Effect of fungal metabolites cytochalasans on lipid droplet formation in mouse macrophages

Effects of seven cytochalasans including cytochalasins B, D and E and novel phenochalasins A and B were tested on cytosolic lipid droplet formation and neutral lipid synthesis in mouse peritoneal macrophages. Phenochalasin A inhibited lipid droplet formation in a dose-dependent manner at least up to 20 microM without any morphological changes in macrophages. Cytochalasins D and E also inhibited lipid droplet formation only in a narrow range of concentrations, around 1 and 0.1 microM, respectively. At higher concentrations they gave morphological changes in macrophages. The other four cytochalasans only showed severe morphological changes in macrophages. Phenochalasin A and cytochalasins D and E inhibited cholesteryl ester (CE) synthesis specifically with IC50 values of 0.61, 2.4 and 0.20 microM, respectively, while the other cytochalasans inhibited both CE and triacylglycerol syntheses. Thus, among the cytochalasans tested, phenochalasin A showed very specific inhibition of CE synthesis and gave the lowest morphological changes in macrophages, resulting in the best inhibitor of lipid droplet formation in macrophages.

The conserved tryptophan-arginine-tyrosine motif of a proteinaceous alpha-amylase inhibitor T-76 from Streptomyces nitrosporeus is important for inhibition of animal alpha-amylases but not for an alpha-amylase from Bacillus sp. no. 195

Site-directed mutagenesis of Trp-16, Arg-17, and Tyr-18, which were thought to form a putative active site in proteinaceous alpha-amylase inhibitor T-76 from Streptomyces nitrosporeus for inhibition, was performed. The mutation at the site (W16A, R17A, and Y18A) resulted in a marked decrease in inhibitory activity against all animal alpha-amylases tested. Only the alpha-amylase from Bacillus sp. no. 195 (BAA) remained sensitive to all the constructed mutant inhibitors. A competition between T-76 mutants and the wild-type for porcine pancreatic alpha-amylase (PPA) suggest that the loss of inhibitory activity against PPA in mutant inhibitors was due to the decrease in their binding ability for PPA. T-76 formed a complex with BAA as well as PPA at the stoichiometric ratio of 1:1. A competition between BAA and the PPA/T-76 complex suggests that PPA and BAA might bind to the same region or regions close to each other on the T-76 molecule. These results indicate that the conserved Trp-Arg-Tyr motif of T-76 is involved in the interaction between T-76 and PPA while other amino acid residues seem to be important for the T-76/BAA interaction. Since the BAA-type alpha-amylase is the actual target of the inhibitors from microbes in comparison with animal alpha-amylases, BAA might be a better material than PPA to elucidate the "true" function of proteinaceous alpha-amylase inhibitors.

Cloning and secretive expression of the gene encoding the proteinaceous alpha-amylase inhibitor paim from Streptomyces corchorusii

A gene encoding the proteinaceous alpha-amylase inhibitor Paim was cloned and sequenced. Southern analysis and the amino acid sequence deduced from the cloned gene indicated that Paim isoforms were encoded in the same gene. When the gene was expressed in Escherichia coli and Streptomyces lividans, recombinant Paim inhibitors were produced in the periplasmic space and in the culture supernatant, respectively. The purified inhibitors had different N-terminal sequences from those of the authentic inhibitors.