Antimicrobial resistance and serotype distribution of Streptococcus pneumoniae strains causing childhood infections in Bangladesh, 1993 to 1997

Three hundred sixty-two Streptococcus pneumoniae strains were isolated from children under 5 years of age at Dhaka Shishu (Children) Hospital from 1993 to 1997. The strains were isolated from blood (n = 105), CSF (n = 164), ear swab (n = 61), eye swab (n = 20), and pus (n = 12). Of the 362 isolates, 42 (11.6%) showed intermediate resistance (MIC, <0.1 microgram/ml) and only 4 (1.1%) showed complete resistance (MIC, >2.0 microgram/ml) to penicillin. Penicillin resistance exhibited a strong relationship with serotype 14; 47.8% of the penicillin-resistant strains belonged to this type. A remarkably high (64.1%) resistance to co-trimoxazole was observed, along with a significant increase during the time period studied; there was no relationship to capsular type. By way of contrast, penicillin resistance did not show any significant change during the study period. Resistance to chloramphenicol (2.2%) and erythromycin (1.1%) was rare. The high resistance to co-trimoxazole and its increasing trend demand elucidation of the clinical impact of pneumonia treatment by this antimicrobial and reconsideration of the World Health Organization recommendation for co-trimoxazole administration to children with community-acquired pneumonia at the health care worker level in Bangladesh.

Interleukin-1 beta upregulates cardiac expression of vascular endothelial growth factor and its receptor KDR/flk-1 via activation of protein tyrosine kinases

Vascular endothelial growth factor (VEGF) is not only an endothelial cell-specific angiogenic factor but also a potent mediator of vascular permeability. Interleukin-1 beta (IL-1 beta) is a pro-inflammatory cytokine that has numerous effects on the pathogenesis of the tissue injury. To explore the possible regulation of the VEGF system by IL-1 beta in the heart, we examined the regulation of expression of VEGF and KDR/flk-1 (one of the VEGF receptors) by IL-1 beta using cardiac myocytes and cardiac microvascular endothelial cells (CMEC). Both cardiac myocytes and CMEC substantially expressed VEGF mRNA and its expression was increased 3.6- and 2.4-fold by IL-1 beta, respectively. IL-1 beta-induced accumulations of VEGF mRNA in cardiac myocytes were abolished by the tyrosine kinase inhibitor genistein, whereas inhibition of protein kinase C (PKC) by staurosporin, calphostin C and phorbol ester-induced PKC depletion, and intracellular Ca2+ chelators did not affect the induction of VEGF mRNA by IL-1 beta. Relatively smaller amounts of KDR/flk-1 mRNA were detected in CMEC, but not in cardiac myocytes, and the analysis using quantitative reverse transcription-polymerase chain reaction revealed that IL-1 beta significantly stimulated the accumulation of KDR/flk-1 mRNA 3.0-fold. VEGF protein (23 kDa) levels in Western blot analysis were increased 4.2- and 3.4-fold by IL-1 beta in cardiac myocytes and CMEC, respectively. KDR/flk-1 protein (230 kDa) levels in CMEC were also increased 3.2-fold by IL-1 beta. In addition, pre-treatment of CMEC by IL-1 beta markedly enhanced VEGF-induced tyrosine phosphorylation of focal adhesion kinase compared with that in the unstimulated cells. These findings indicate that cardiac VEGF-KDR/flk-1 system is upregulated by IL-1 beta via activation of tyrosine kinases, suggesting that the IL-1 beta-modulated autocrine and/or paracrine system of VEGF has an important role in the process of angiogenesis in ischemic hearts.

Safety and Efficacy of the Neuraminidase Inhibitor Zanamivir in Treating Influenza Virus Infection in Adults: Results from Japan

The study was carried out to evaluate the therapeutic effects of zanamivir, a highly selective, potent and specific inhibitor of influenza A and B virus neuraminidases, in adult patients with acute influenzalike illness. Patients who presented within 36 h of the onset of influenza-like symptoms were randomly assigned to receive one of three treatments, twice daily, for 5 days: 10 mg zanamivir powder for inhalation (zanamivir inhalation group), 10 mg zanamivir powder for inhalation plus 6.4 mg zanamivir nasal spray (zanamivir inhalation plus intranasal group) or placebo (placebo group). The primary end point was the time to alleviation of the three major symptoms (fever, headache and myalgia). The secondary end point was the time to alleviation of five influenza symptoms (fever, headache, myalgia, cough and sore throat). One hundred and sixteen patients with influenza-like illness were recruited to the study. No differences were observed between the two groups of patients who received zanamivir (inhalation group or inhalation plus intranasal group). Patients who received zanamivir recovered significantly faster (median 3 days to recovery) than the patients in the placebo group (median 4 days to recovery; P<0.01). Topically administered zanamivir was well tolerated. This study confirms that in adults, topically administered zanamivir is well tolerated and is effective in reducing the time to alleviation of influenza symptoms.

Differential kinetics of circulating angiotensin IV and II after treatment with angiotensin II type 1 receptor antagonist and their plasma levels in patients with chronic renal failure

BACKGROUND

Angiotensin II (Ang II) C-terminal hexapeptide (referred to as Ang IV) possesses the characteristics of a real hormone with specific receptors and biological effects. Clinical application of Ang II type 1 receptor (AT1-R) antagonists cause an increase in plasma Ang II level, which may result in enhanced production of Ang IV.

PATIENTS AND METHODS

In this study, we measured plasma Ang IV and Ang II levels in patients with chronic renal failure (CRF), and also examined the changes in Ang IV and Ang II levels after administration of an ATI-R antagonist.

RESULTS

Ang II and Ang IV levels in CRF patients untreated with hemodialysis (n = 16) were 15.8+/-3.6 and 6.0+/-1.1 pg/ml, respectively, which did not differ significantly from Ang II (20.6+/-2.4) and Ang IV levels (8.6+/-1.1) in normal controls (n = 23). The ratio of Ang IV to Ang II was 38%, similar to that in the controls (41%). Ang II or Ang IV levels in CRF patients treated with hemodialysis (n = 12) were also similar to the control values. Ang IV levels had a significant correlation with Ang II levels (r = 0.59). When hypertensive patients were treated with an AT1-R antagonist candesartan for 7 days, Ang II and Ang IV levels were increased 5.5- and 4.1-fold relative to the control levels, respectively. Ang II levels 28 and 56 days after treatment were significantly lower than those 7 days after treatment, whereas Ang IV levels did not differ significantly from those 7 days after treatment. Similar differential kinetics in Ang II and Ang IV levels after long-term (90 days) treatment with an AT1-R antagonist was also confirmed in experiments using rats. Significant decrease in blood pressure continued during long-term treatment with an AT1-R antagonist.

CONCLUSION

These findings demonstrated that plasma Ang IV levels in patients with CRF did not differ significantly from those in normal subjects, and that treatment with an AT1-R antagonist caused marked increases in both Ang II and Ang IV levels. In contrast, during long-term treatment plasma Ang II levels were more rapidly decreased than Ang IV levels, suggesting longer-lasting enhancement of the action of Ang IV rather than that of Ang II after treatment with an AT1-R antagonist.

Comparison of gene structures and enzymatic properties between two endoglucanases from Humicola grisea

We have cloned two endoglucanase genes (egl3 and egl4) from a thermophilic fungus, Humicola grisea. The coding region of the egl3 gene was interrupted by an intron of 56-bp, and the deduced amino acid sequence of the egl3 gene was 305 amino acids in length and showed 98.4% identity with Humicola insolens EGV. The coding region of the egl4 gene was also interrupted by an intron of 173-bp, which contains 34 TTC repeated sequence units, and the deduced amino acid sequence of the egl4 gene was 227 amino acids in length and showed 61.5% identity with H. grisea EGL3. The typical hinge and the cellulose-binding domain were observed in the C-terminal region of EGL3, but they were not observed in EGL4. In the 5' upstream region of both genes, there were a TATA box or its similar sequence, CAAT motifs, and 6-bp sites which are identical or similar to the consensus sequence for binding a catabolite repressor CREA in Aspergillus nidulans. The egl3 and the egl4 genes were expressed in Aspergillus oryzae, and the translation products were purified. The fusion protein, EGL4CBD, which consists of a catalytic domain of EGL4 and the C-terminal region of EGL3, was also constructed and produced by A. oryzae, and purified. These enzymes showed relatively high activity toward carboxymethyl cellulose (CMC) and could not hydrolyze p-nitrophenyl-beta-D-glucoside and p-nitrophenyl-beta-D-cellobioside. The positive effect of substituting the C-terminal region of EGL4 with that of EGL3 was observed in the hydrolysis of CMC.

Attachment of Burkholderia pseudomallei to pharyngeal epithelial cells: a highly pathogenic bacteria with low attachment ability

Respiratory infections are initiated by the attachment of bacteria to pharyngeal epithelial cells. We studied the attachment of Burkholderia pseudomallei to pharyngeal epithelial cells. After one, two, three, and four washes, there were 22.6+/-8.9, 15.7+/-7.0, 6.8+/-3.1, and 4.6+/-1.1 (mean+/-SD) attached bacteria/cell, respectively. If the bacterial concentration was maintained at 1 X 10(8) colony-forming units (cfu)/ml and three washes were done, at concentrations of 2.5 x 10(4), 5 X 10(4), and 1 x 10(5) cells/ml there were 9.9+/-3.6, 3.3+/-0.8, and 2.5+/-1.1 attached bacteria/cell, respectively. If the cell concentration was kept at 2.5 x 10(4) cells/ml and three washes were done, at bacterial concentrations of 1 x 10(5), 1 X 10(6), 1 X 10(7), 1 x 10(8), and 1 x 10(9) cfu/ml, there were 0.3+/-0.3, 0.6+/-0.6, 1.0+/-0.2, 5.1+/-2.3, and 9.6+/-1.9 attached bacteria/cell, respectively. There were 4.8+/-1.9, 5.5+/-2.5, 5.6+/-1.9, and 6.4+/-2.6 attached bacteria/cell at 0, 30, 120, and 240 min of incubation, respectively. Pharyngeal cells from 10 persons (seven men and three women, mean+/-SD age = 30.7+/-8.1 years, 12 experiments with a single isolate) showed that there were 7.8+/-4.3 attached bacteria/cell. It was found that the efficiency of attachment of this bacteria was very low (7.0+/-3.3 bacteria/cell). Electron microscopy revealed that there were no fimbriae but a thin capsular polysaccharide layer on the surface of B. pseudomallei. Attachment to pharyngeal epithelial cells appeared to be mediated by this structure.

Primary aldosteronism with aldosterone-producing adrenal adenoma in a pregnant woman

A 30-year-old pregnant woman complained of muscle weakness at 29 weeks' gestation. She was hypertensive with severe hypokalemia. Lower plasma renin activity and higher aldosterone level than the normal values in pregnancy suggested primary aldosteronism. A cesarean delivery was performed at 31 weeks' gestation because of pulmonary congestion. The neonatal course was uncomplicated. The laparoscopic adrenalectomy for a 2.0-cm right adrenal adenoma resulted in normalizing of her blood pressure and serum potassium level. Although primary aldosteronism is rare, especially during pregnancy, it should be always considered as one of etiologies of hypertension in pregnancy.

Isolation of pathogenic bacteria from induced sputum from hospitalized children with pneumonia in Bangladesh

A prospective study was carried out on 157 patients admitted to a paediatric hospital in Dhaka, Bangladesh to determine the bacteria present in the induced sputum of paediatric patients with X-ray proven pneumonia. Their ages ranged from 21 days to 11 years; 65 per cent of them were male and 35 per cent were female. The most affected age group was between 6 months and 2 years old. Respiratory secretions produced by induced cough were taken by swab from the oropharynx for culture and smear. The predominant bacteria were Haemophilus influenzae, Streptococcus pneumoniae, Branhamella catarrhalis and Gram-negative bacilli. Serotyping of H. influenzae revealed that 76 per cent were non-typable and 18 per cent were of type b; 23.5 per cent of isolates of H. influenzae were beta-lactamase producing. MIC90 of penicillin against S. pneumoniae and H. influenzae were 0.025 and 3.13 micrograms/ml respectively. Ampicillin, penicillin G (benzylpenicillin), amoxycillin, and gentamicin were administered for the treatment of these patients. All cases were apparently improved, on the basis of clinical evaluation, and discharged from the hospital.

Isolation of the creA gene from the cellulolytic fungus Humicola grisea and analysis of CreA binding sites upstream from the cellulase genes

A carbon catabolite repressor gene, creA, was isolated from the cellulolytic fungus Humicola grisea by using a portion of the Trichoderma reesei cre1 gene as a probe. The deduced amino acid sequence predicts a zinc finger protein of 419 amino acids in length, and its zinc finger regions show high similarity with those of Aspergillus CreAs, T. reesei Cre1, and Saccharomyces cerevisiae MIG1. Northern blot analysis showed that the H. grisea creA gene was highly transcribed when the mycelia were grown on glucose-containing media, but the transcription of the H. grisea endoglucanase 1 gene (egl1) and the exoglucanase 1 gene (exo1) were repressed under these conditions. Results of binding assays with the maltose-binding protein::CreA(1-166) fusion protein and the egl1 and the exo1 upstream regions showed that some 6-bp sites having an identical or similar sequence to the consensus sequence for CreA binding were protected from DNase I digestion.

Characterization of the I-E(d)--restricted peptide recognized by an anti-idiotypic CD4+ T cell line

We have previously reported a CD3+ CD4+ CD8- T cell line, J-2R which specifically recognized J558 individual idiotope (IdI) of anti-alpha (1-->3) dextran antibodies in an I-E(d) restricted manner. The J-2R proliferated in response to J558 IdI-derived peptides; however, the ability of the peptides to evoke the proliferation of J-2R was different. In the present study, we investigated the interaction between J558 IdI-derived peptides and I-E(d) molecules in competition experiments using a M104E IdI-derived peptide, M88-105. The M88-105 inhibited the proliferation of J-2R induced by J558 IdI-derived peptides. Furthermore, the proliferation induced by the peptides J92-109 and J96-105 was inhibited by the M88-105 at much lower inhibitor/antigenic peptide ratios, compared to the proliferation induced by the J88-105. Thus, shift of the framework to C-terminus and deletion of N-terminus amino acid residues from the 18-mer peptide J88-105 made the peptides more susceptible to the inhibition by the M88-105. Sequencing of the J-2R T cell receptor (TcR) revealed that J-2R used TcR, V alpha 1, J alpha 44; V beta 15, D beta 1, J beta 1.5. These results suggest that the peptides, J88-105, J92-109 and J96-105, directly bind to I-E(d) molecules, and that the capacity of J558 IdI-derived peptides to activate J-2R depends on the affinity to the I-E(d) molecules.

Angiotensin II type 2 receptor is upregulated in human heart with interstitial fibrosis, and cardiac fibroblasts are the major cell type for its expression

The expression pattern of angiotensin (Ang) II type 2 receptor (AT2-R) in the remodeling process of human left ventricles (LVs) remains poorly defined. We analyzed its expression at protein, mRNA, and cellular levels using autopsy, biopsy, or operation LV samples from patients with failing hearts caused by acute (AMI) or old (OMI) myocardial infarction and idiopathic dilated cardiomyopathy (DCM) and also examined functional biochemical responses of failing hearts to Ang II. In autopsy samples from the nonfailing heart group, the ratio of AT1-R and AT2-R was 59% and 41%, respectively. The expression of AT2-R was markedly increased in DCM hearts at protein (3.5-fold) and mRNA (3.1-fold) levels compared with AMI or OMI. AT1-R protein and mRNA levels in AMI hearts showed 1.5- and 2.1-fold increases, respectively, whereas in OMI and DCM hearts, AT1-R expression was significantly downregulated. AT1-R-mediated response in inositol phosphate production was significantly attenuated in LV homogenate from failing hearts compared with nonfailing hearts. AT2-R sites were highly localized in the interstitial region in either nonfailing or failing heart, whereas AT1-R was evenly distributed over myocardium at lower densities. Mitogen-activated protein kinase (MAPK) activation by Ang II was significantly decreased in fibroblast compartment from the failing hearts, and pretreatment with AT2-R antagonist caused an additional significant increase in Ang II-induced MAPK activity (36%). Cardiac hypertrophy suggested by atrial and brain natriuretic peptide levels was comparably increased in OMI and DCM, whereas accumulation of matrix proteins such as collagen type 1 and fibronectin was much more prominent in DCM than in OMI. These findings demonstrate that (1) AT2-R expression is upregulated in failing hearts, and fibroblasts present in the interstitial regions are the major cell type responsible for its expression, (2) AT2-R present in the fibroblasts exerts an inhibitory effect on Ang II-induced mitogen signals, and (3) AT1-R in atrial and LV tissues was downregulated during chronic heart failure, and AT1-R-mediated functional biochemical responsiveness was decreased in the failing hearts. Thus, the expression level of AT2-R is likely determined by the extent of interstitial fibrosis associated with heart failure, and the expression and function of AT1-R and AT2-R are differentially regulated in failing human hearts.

Overproduction of recombinant Trichoderma reesei cellulases by Aspergillus oryzae and their enzymatic properties

We have established an expression system of Trichoderma reesei cellulase genes using Aspergillus oryzae as a host. In this system, the expression of T. reesei cellulase genes were regulated under the control of A. oryzae Taka-amylase promoter and the cellulase genes were highly expressed when maltose was used as a main carbon source for inducer. The production of recombinant cellulases by A. oryzae transformants reached a maximum after 3-4 days of cultivation. In some cases, proteolysis of recombinant cellulases was observed in the late stage of cultivation. The recombinant cellulases were purified and characterized. The apparent molecular weights of recombinant cellulases were more or less larger than those of native enzymes. The optimal temperatures and pHs of recombinant cellulases were 50-70 degrees C and 4-5, respectively. Among the recombinant cellulases, endoglucanase I showed broad substrate specificities and high activity when compared with the other cellulases investigated here.

Isolation of the gene and characterization of the enzymatic properties of a major exoglucanase of humicola grisea without a cellulose-binding domain

An exoglucanase gene was cloned from a cellulolytic fungus, Humicola grisea. DNA sequencing of this gene, designated as exo1, revealed that it contained four introns in the coding region. The deduced amino acid sequence of EXO1 was 451 amino acids in length and showed 57.7% identity with that of H. grisea cellobiohydrolase 1 (CBH1), but lacked the typical domain structures of a cellulose-binding domain and a hinge region. Transcriptional analysis of the exo1 and cbh1 genes showed that the expression of these genes was induced by Avicel, and repressed in the presence of glucose. The exo1 gene was expressed in Aspergillus oryzae, and the recombinant EXO1 protein was purified. EXO1 and CBH1 produced by A. oryzae showed relatively higher activity toward Avicel, but showed much lower activity toward carboxymethyl cellulose (CMC) and p-nitrophenyl-beta-D-cellobioside (PNPC), than H. grisea endoglucanase 1 (EGL1). The addition of a cellulose-binding domain and a hinge region to EXO1 caused decreases in its enzymatic activities as well as the deletion of the cellulose-binding domain from CBH1. EXO1 showed relatively weak or no synergistic activity toward Avicel with H. grisea endoglucanases, but showed a significant level of apparent synergism with H. grisea CBH1 and Trichoderma reesei EGLI. CBH1 showed a significant level of apparent endo-exo synergism with H. grisea and T. reesei endoglucanases. H. grisea has at least two different types of major exoglucanase components and shows strong cellulolytic activity through synergism with cellulase components including EXO1 and CBH1.

Role of calcium-sensitive tyrosine kinase Pyk2/CAKbeta/RAFTK in angiotensin II induced Ras/ERK signaling

In cardiac fibroblasts, angiotensin II (Ang II) induced a rapid increase in extracellular signal regulated kinase (ERK) activity in a pertussis toxin insensitive manner. This ERK activation was abolished by the Gq-associated phospholipase C inhibitor U73122 but was insensitive to protein kinase C (PKC) inhibitors or PKC downregulation by phorbol ester. Intracellular Ca2+ chelation by BAPTA-AM or TMB-8 abolished Ang II induced ERK activation, whereas treatment with EGTA or nifedipine did not affect it. Ca2+ ionophore A23187 also induced a rapid increase in ERK activity to an extent similar to that of Ang II stimulation. Calmodulin inhibitors (W7 and calmidazolium) and tyrosine kinase inhibitors (genistein and ST638) completely blocked ERK activation by Ang II and A23187. Both Ang II and A23187 caused a rapid increase in the binding of GTP to p21(Ras), which was nearly abolished by genistein and calmidazolium. Transfection with the dominant negative mutant of Ras and the Ras inhibitor manumycin completely inhibited Ang II induced ERK activation. It was also found for the first time that cardiac fibroblasts abundantly expressed Ca2+-sensitive tyrosine kinase Pyk2/CAKbeta/RAFTK and that Ang II markedly induced its activation in a Ca2+/calmodulin-sensitive manner. Overexpression of the dominant negative mutant of Pyk2 significantly attenuated Ang II or A23187-induced ERK activities (36% and 38% inhibition compared with that in mock-transfected cells, respectively) and ERK tyrosine phosphorylation levels, as well as an increase in the binding of GTP to p21(Ras). These findings demonstrate that in cardiac fibroblasts, Ang II induced Ras/ERK activation is dominantly regulated by Gq-coupled Ca2+/calmodulin signaling and that Pyk2 plays an important role in the signal transmission for efficient activation of the Ang II induced Ras/ERK pathway.

Left ventricular mass regression after implantation of St. Jude Medical cardiac valves in small aortic roots

In this study, we analyzed the extent of regression of left ventricular hypertrophy in patients who received small St. Jude Medical (SJM) aortic valves and compared the results with those of another group receiving larger valves. Eighty-eight patients received either 19 or 21 mm valves (Group 1, 25 patients) or either 23 or 25 mm valves (Group 2, 53 patients). Echocardiographic studies were done before the operation and 5 years postoperatively. At follow-up a significant reduction in the left ventricular mass was found for both patient groups (p < 0.0001). Doppler echocardiography derived pressure gradients for both groups were obtained during the follow-up period. As expected, the patients in Group 1 had higher peak pressure gradients than did those in Group 2. However, there was no significant difference between the 2 groups or any significant correlations between peak pressure gradients and body surface area (BSA). Actuarial survival was 84.7% at 15 years for Group 1 and 85.9% at 17 years for Group 2. Actuarial freedom from valve related events was 91.4% at 15 years for Group 1 and 82.7% at 17 years for Group 2. There was no significant difference in survival or valve related event free curves between the 2 groups. After implantations of SJM valves in small aortic roots, significant left ventricular mass regression was obtained, and the results were comparable to those for valves of other sizes. The long-term performance of aortic valve replacement with small valves was satisfactory as judged by improvement in the functional class of patients and survival statistics, the durability of the prosthesis, and valve related morbidity comparable to that of valves of other sizes.

Tissue-specific expression of human angiotensin II AT1 and AT2 receptors and cellular localization of subtype mRNAs in adult human renal cortex using in situ hybridization

All studies analyzing the localization of angiotensin II (Ang II) receptors in the human kidney have been performed at the protein level using 125I-Ang II as a probe. In this study, cellular localizations of Ang II type l (AT1-R) and type 2 (AT2-R) receptor mRNAs in the adult human renal cortex were examined for the first time using in situ hybridization, and their expression patterns determined by RNase protection assay were compared with those in other human tissues. In the human renal cortex obtained from tumor-free portions in renal cell carcinoma, AT1-R mRNA levels were about 8- to 10-fold higher than AT2-R mRNA levels. Human liver and aorta predominantly expressed AT1-R mRNA, while human right atrium contained both AT1-R and AT2-R mRNAs. Ligand-binding assays revealed that the total Ang II receptor number in the human renal cortex was 16.0 +/- 3.3 fmol/mg protein, similar to that in liver (17.7 +/- 5. 8) but significantly higher than in right atrium (11.6 +/- 3.2) and aorta (5.6 +/- 2.7). Relative distribution ratios of AT1-R and AT2-R numbers in the renal cortex and right atrium were 82/17 and 56/42%, respectively. In situ hybridization study indicated that strongest AT1-R mRNA signals were located in interlobular arteries and tubulointerstitial fibrous regions surrounding interlobular arteries and glomeruli, followed in decreasing order by glomeruli and cortical tubules. Expression of AT2-R mRNA was highly localized in interlobular arteries. Cells present in tubulointerstitial regions were positive for vimentin and collagen type 1, indicating that the majority of the cells present in the regions are fibroblasts. Presence of strong AT1-R mRNA signals in the tubulointerstitial fibrous regions surrounding arteries and glomeruli and the expression of AT2-R mRNA in the interlobular artery were the first evidence, suggesting a pharmacological framework for the differential effects of Ang II receptor subtype mediated renal function in the adult human kidney.

Protective effects of baicalein against cell damage by reactive oxygen species

Baicalein (5,6,7-trihydroxy-2-phenyl-4H-1-benzopyran-4-one), a naturally occurring flavonoid, was found to prevent human dermal fibroblast cell damage induced by reactive oxygen species such as hydrogen peroxide (H2O2), tert-butyl hydroperoxide (BuOOH) and superoxide anions (.O2-) in a concentration-dependent manner, and was more effective than the iron chelator, deferoxamine, hydroxyl radical (.OH) scavengers such as dimethyl sulfoxide (DMSO) and ethanol (EtOH), the lipid peroxidation chain blocker, alpha-tocopherol (Vit. E) and the xanthine oxidase inhibitor, allopurinol. To probe the mechanism of cell defense, the reaction of baicalein with oxygen free radicals was investigated using electron spin resonance (ESR) spectrometry. Baicalein decreased the signal intensities due to the 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) spin adducts of .OH, .O2- and tert-butyl peroxyl (BuOO.) radicals in a concentration-dependent manner. The IC50 values, which are the 50% inhibition concentrations of baicalein for the free radicals, were 10, 45 and 310 microM, respectively. These results suggested that baicalein possesses free radical scavenging ability which prevents the fibroblast damage induced by these free radical species.

[Long-term follow-up of patients with small St. Jude aortic valve prostheses]

Thirty-five patients received small sized 19 or 21 mm valves (group I) and 53 patients received 23 or 25 mm valves (group II). At follow-up a significant reduction in the left ventricular mass was found for both patient groups (p < 0.0001). The patients in group I had higher peak pressure gradients than did those in group II. However, there was no significant difference between the two groups, or any significant correlation between peak pressure gradients and body surface area. Actuarial survival was 84.7% at 15 years for group I and 85.9% at 17 years for group II. Actuarial freedom from valve-related events was 91.4% at 15 years for group I and 82.7% at 17 years for group II. There was no significant difference in survival or valve-related event free curves between the two groups. After implantation of small SIM valves, significant left ventricular mass regression was obtained and the results were comparable to those for valves of other sizes. The long-term performance of aortic valve replacement with small valves was satisfactory as judged by improvement in the functional class of patients, survival statistics, the durability of the prosthesis, and valve related morbidity comparable to that of valves of other sizes.

A clinical analysis of the recovery from sensory disturbance after sagittal splitting ramus osteotomy using a Semmes-Weinstein pressure aesthesiometer

A number of studies of evaluation methods for sensory disturbance after sagittal splitting ramus osteotomy (SSRO) are known. To compare postoperative sensory disturbances among patients in different hospitals, a highly reproducible and standardized sensory test is required. In the present study, we measured the tactile threshold in the region innervated by the mental nerves in 45 patients (90 sides) after SSRO using a Semmes-Weinstein pressure aesthesiometer. The percentage of recovery to the normal level defined by Bell was 72.2% at one week, 82.2% at 4 weeks, and 90.0% at 8 weeks after SSRO. The recovery process was evaluated by classifying the postoperative sensory disturbance into 5 grade levels according to Bell's interpretation scale. The results showed that the SW sensory test is useful for evaluation of the recovery process from sensory disturbance after SSRO. Some improvements of this test were also discussed.

Enhanced negative slope of the readiness potential preceding a target force production task

Readiness potentials (RPs) preceding a trigger pulling movement were recorded in 9 right-handed male subjects. We investigated two tasks, non-purposive and purposive movement tasks. In this study we defined simple trigger pull as non-purposive, and target force production by pulling the trigger as purposive. In the non-purposive task, the subjects were instructed to pull the trigger at their own pace and at an easily-exerted force level. After two sessions in the non-purposive movement task, the subjects were submitted to the purposive movement task, and were requested to pull the trigger in an attempt to produce target force, the range of which was decided individually on the basis of mean force level in the second session of the non-purposive movement task. The RP preceding the purposive movement was larger than that preceding the non-purposive movement. In addition, enhancement of the RP was specific to the negative slope (NS'). Since neither peak force nor time to peak force of the movement differed in the two tasks, it was concluded that the increased NS' was due to a psychological change associated with execution of the purposive movement.

[Immune complex-mediated glomerulonephritis associated with infective endocarditis with aortic valve vegetation]

A 61-year-old male was referred to our hospital for rapidly progressive azotemia. He was also found to have huge vegetation at the aortic valve causing regurgitation. Biochemical examinations revealed the presence of an immunocomplex associated with decreased circulating complements. In biopsy samples from the kidney, we found the presence of fibrillar crescents, proliferation of mesangial cells, increase in extracellular matrix proteins, atrophy of tubules, infiltration of mononuclear cells in the interstitial regions, high density deposits in the mesangial area and mesangial interposition. Since the patient strongly rejected operative treatment by valvular replacement, we continued non-invasive treatment such as hemodialysis and treatment with penicillin G. This transiently improved the condition of the patient, including biochemical data and cardiac function, but there was no reduction in the size of vegetation at the aortic valve and the bacteria responsible for infective endocarditis were not identified. About three months after admission, overt signs of congestive heart failure emerged and the patients was subjected to intensive care with a respirator and hemodynamic monitoring. Although the cardiac function was improved, concomitant severe pneumonia occurred and the patient died of septic shock. Thus, we report a rare case in whom immune complex-mediated glomerulonephritis was associated with infective endocarditis with aortic valve vegetation.

[Pathophysiological function of angiotensin II AT1 and AT2 receptors and clinical application of AT1 antagonists]

Angiotensin II (Ang II) receptors are classified into two subtypes, type 1 (ATF-R) and type 2 (AT2-R) by development of non-peptidic antagonists. Classical Ang II function including vasopressor effect, cardiotropic action and aldosterone production is mainly mediated through AT1-R that present in cardiovascular system, adrenal glands and kidneys. AT1-R is abundantly expressed in whole bodies of fetus and its expression is abruptly decreased after birth, and in the adult AT2-R is expressed in brain nuclei, uterus, adrenal medullary glands and ovary. AT1-R and AT2-R are both G-protein coupled receptors and have 46% similarity in amino acid levels with seventh transmembrane conformation. Signal transduction pathway of AT1-R is mainly CA2+ and activation of protein kinase C, while that of AT2-R is still unknown. Clinical application of AT1-R antagonist started and this causes elevation of plasma Ang II levels, which selectively stimulates AT2-R. Thus, one should realize AT2-R-mediated effect in treatment with AT1-R antagonist. We have shown that AT2-R has anti-AT1-R action, such as inhibitory action against AT1-R-mediated positive chronotropic effect or AT1-R-induced proliferative effect, resulting in the protective effects on Ang II-induced cardiovasucular and renal action. Thus, elucidation of AT2-R function will be important in clinical treatment with AT1-R antagonists.

Angiotensin II type 1 receptor-induced extracellular signal-regulated protein kinase activation is mediated by Ca2+/calmodulin-dependent transactivation of epidermal growth factor receptor

The signaling cascade elicited by angiotensin II (Ang II) resembles that characteristic of growth factor stimulation, and recent evidence suggests that G protein-coupled receptors transactivate growth factor receptors to transmit mitogenic effects. In the present study, we report the involvement of epidermal growth factor receptor (EGF-R) in Ang II-induced extracellular signal-regulated kinase (ERK) activation, c-fos gene expression, and DNA synthesis in cardiac fibroblasts. Ang II induced a rapid tyrosine phosphorylation of EGF-R in association with phosphorylation of Shc protein and ERK activation. Specific inhibition of EGF-R function by either a dominant-negative EGF-R mutant or selective tyrphostin AG1478 completely abolished Ang II-induced ERK activation. Induction of c-fos gene expression and DNA synthesis were also abolished by the inhibition of EGF-R function. Calmodulin or tyrosine kinase inhibitors, but not protein kinase C (PKC) inhibitors or downregulation of PKC, completely abolished transactivation of EGF-R by Ang II or the Ca2+ ionophore A23187. Epidermal growth factor (EGF) activity in concentrated supernatant from Ang II-treated cells was not detected, and saturation of culture media with anti-EGF antibody did not affect the Ang II-induced transactivation of EGF-R. Conditioned media in which cells were incubated with Ang II could not induce phosphorylation of EGF-R on recipient cells. Platelet-derived growth factor-beta receptor was not phosphorylated on Ang II stimulation, and Ang II-induced c-jun gene expression was not affected by tyrphostin AG1478. Our results demonstrated that in cardiac fibroblasts Ang II-induced ERK activation and its mitogenic signals are dominantly mediated by EGF-R transactivated in a Ca2+/calmodulin-dependent manner and suggested that the effects of Ang II on cardiac fibroblasts should be interpreted in association with the signaling pathways regulating cellular proliferation and/or differentiation by growth factors.

Colicin E5 as a new type of cytotoxin, which cleaves a specific group of tRNAs

The C-terminal active domain of colicin E5 has a novel ribonuclease activity which specifically cleaves queuine-containing tRNAs. Colicin E5 is a new type cytotoxin targeting a group of tRNAs.

A case of Guillain-Barré syndrome associated with human parvovirus B19 infection

We report a 4-year-old boy who presented with Guillain-Barré Syndrome 11 days after the onset of erythema infectiosum. The illness resolved without gamma globulin therapy.