Effect of rpoS mutations on stress-resistance and invasion of brain microvascular endothelial cells in Escherichia coli K1

Escherichia coli K1 strains are predominant in causing neonatal meningitis. We have shown that invasion of brain microvascular endothelial cells (BMEC) is a prerequisite for E. coli K1 crossing of the blood-brain barrier. BMEC invasion by E. coli K1 strain RS218, however, has been shown to be significantly greater with stationary-phase cultures than with exponential-phase cultures. Since RpoS participates in regulating stationary-phase gene expression, the present study examined a possible involvement of RpoS in E. coli K1 invasion of BMEC. We found that the cerebrospinal fluid isolates of E. coli K1 strains RS218 and IHE3034 have a nonsense mutation in their rpoS gene. Complementation with the E. coli K12 rpoS gene significantly increased the BMEC invasion of E. coli K1 strain IHE3034, but failed to significantly increase the invasion of another E. coli K1 strain RS218. Of interest, the recovery of E. coli K1 strains following environmental insults was 10-100-fold greater on Columbia blood agar than on LB agar, indicating that growing medium is important for viability of rpoS mutants after environmental insults. Taken together, our data suggest that the growth-phase-dependent E. coli K1 invasion of BMEC is affected by RpoS and other growth-phase-dependent regulatory mechanisms.

Inhibition of aminopeptidase P potentiates wheal response to bradykinin in angiotensin-converting enzyme inhibitor-treated humans

Bradykinin is a nonapeptide that contributes to the cardioprotective effects of angiotensin-converting enzyme (ACE) inhibitors. During ACE inhibition, an increased proportion of bradykinin is degraded through non-ACE pathways. Studies in animals suggest that aminopeptidase P (EC 3.4.11.9) may contribute to the metabolism of bradykinin. The purpose of the present study was to determine the contribution of aminopeptidase P to the degradation of bradykinin in humans in the presence and absence of ACE inhibition. To do this, we measured the wheal response to intradermal injection of bradykinin (0, 1, or 10 nicrog) in the presence or absence of intradermal administration of the specific aminopeptidase P inhibitor apstatin (5 or 10 microg) and oral administration of the ACE inhibitor quinapril (10 mg) in six healthy subjects. Both bradykinin (ANOVA; F = 101.18, P <.001) and apstatin alone (F = 7.01, P =.049) caused a wheal of dose-dependent size. There was no significant interaction between apstatin and bradykinin (F = 4.94, P =.175). Pretreatment with 10 mg of quinapril significantly shifted the dose-response curve for bradykinin to the left (effect of quinapril; F = 77.96, P <.001) and there was significant interaction between quinapril and bradykinin (F = 7.82, P =.041). The effect of quinapril was significantly potentiated by coinjection of 10 microg of apstatin (effect of apstatin; F = 21.60, P =.006), such that there was significant interactive effect of quinapril and apstatin (F = 20.83, P =.006) on the wheal response to bradykinin. Collectively, these data suggest that aminopeptidase P plays a minor role in the degradation of bradykinin in human skin in the absence of ACE inhibition but contributes significantly to the degradation of bradykinin in the presence of ACE inhibition.

Descriptive epidemiology of physical activity in African-American women

OBJECTIVES

We assessed walking for exercise and moderate and strenuous physical activity in relation to both demographic and health-related characteristics among African-American women from various parts of the United States who participate in the Black Women's Health Study.

METHODS

The data were collected in 1995 by mail questionnaire from 64,524 U.S. black women aged 21 to 69 years. The 64,101 women who provided data on physical activity are the subjects of the present report.

RESULTS

The present study revealed low levels of physical activity among the African-American women: 57% reported an hour or less per week walking for exercise, 18% reported moderate activity, and 61% reported strenuous physical activity. Strenuous physical activity increased with education. Higher levels of walking for exercise and moderate and strenuous activity were associated with higher levels of participation in strenuous exercise in high school.

CONCLUSION

Physical activity levels are low in African-American women. Based on the findings of the present study it may be suggested that educational efforts to increase levels of physical activity should start at an early age.

Decreased oral bioavailability of loxoprofen at second administration in human subjects

The objective of this study was to determine the extent of period effect on the pharmacokineitcs of loxoprofen during consecutive dosing. Loxipen and Loxonin tablets were administered to 16 healthy Korean male subjects at a single dose of 60 mg as loxoprofen sodium anhydrous in a 2 x 2 crossover investigation with a two-week wash-out phase. Concentrations of loxoprofen in plasma were measured by HPLC method for 6 h. The two formulations were found bioequivalent, but analysis of variance (ANOVA) indicated that there was a significant (p < 0.05) period effect in AUCinf (area under the plasma concentration-time curve from time zero to infinity) between the administrations. A 20% decrease in the AUC was seen at the second administration. This period effect on pharmacokinetics of loxoprofen may be relevant for the patients who need consecutive administration of the drug.

Synergistic effect of adrenal steroids and angiotensin II on plasminogen activator inhibitor-1 production

Recent data suggest an interaction between the renin-angiotensin-aldosterone system and fibrinolysis. Although previous work has focused on the effect of angiotensin II (Ang II) on plasminogen activator inhibitor (PAI-1) expression, the present study tests the hypothesis that aldosterone contributes to the regulation of PAI-1 expression. To test this hypothesis in vitro, luciferase reporter constructs containing the human PAI-1 promoter were transfected into rat aortic smooth muscle cells. Exposure of the cells to 100 nmol/L Ang II resulted in a 3-fold increase in luciferase activity. Neither 1 micromol/L dexamethasone nor 1 micromol/L aldosterone alone increased PAI-1 expression. However, both dexamethasone and aldosterone enhanced the effect of Ang II in a dose-dependent manner. This effect was abolished by mutation in the region of a putative glucocorticoid-responsive element. A similar interactive effect of Ang II and aldosterone was observed in cultured human umbilical vein endothelial cells. The time course of the effect of aldosterone on Ang II-induced PAI-1 expression was consistent with a classical mineralocorticoid receptor mechanism, and the effect of aldosterone on PAI-1 synthesis was attenuated by spironolactone. To determine whether aldosterone affected PAI-1 expression in vivo, we measured local venous PAI-1 antigen concentrations in six patients with primary hyperaldosteronism undergoing selective adrenal vein sampling. PAI-1 antigen, but not tissue plasminogen activator antigen, concentrations were significantly higher in adrenal venous blood than in peripheral venous blood. Taken together, these data support the hypothesis that aldosterone modulates the effect of Ang II on PAI-1 expression in vitro and in vivo in humans.

Protective effects of Orostachys japonicus A. Berger (Crassulaceae) on H2O2-induced apoptosis in GT1-1 mouse hypothalamic neuronal cell line

Oxidative stress is a major cause of neurodegenerative diseases, so the protection of neuronal cells from reactive oxygen species can be beneficial for the prevention and treatment of these diseases. Methanol extract of Orostachys japonicus A. Berger (Crassulaceae), a traditional oriental medical herb, was shown to have a protective effect on H2O2-induced apoptosis in GT1-1 mouse hypothalamic neuronal cell line which was detected by flow cytometry after propidium iodide staining. Among fractions of O. japonicus, chloroform fraction had the highest protective effect, and water fraction had no protective effect suggesting that the active ingredients might be hydrophobic compounds.

Tendency for local repetitiveness in amino acid usages in modern proteins

Systematic analyses of human proteins show that neural and immune system-specific, and therefore, relatively "modern" proteins have a tendency for repetitive use of amino acids at a local scale ( approximately 1-20 residues), while ancient proteins (human homologues of Escherichia coli proteins) do not. Those protein subsegments which are unique based on homology search account for the repetitiveness. Simulation shows that such repetitiveness can be maintained by frequent duplication on a very short scale (one to two codons) in the presence of substitutive point mutation, while the latter tends to mitigate the repetitiveness. DNA analyses also show the presence of cryptic (i.e. "out of the codon frame") repetitiveness, which cannot fully be explained by features in protein sequences. Simulative modification of the amino acid sequences of immune system-specific proteins estimate that 2.4 duplication events occur during the period equivalent to ten events of substitution mutation. It is also suggested that the repetitiveness leads to longitudinal unevenness within a given peptide domain. Those peptide motifs which contain similarly charged residues are likely to be generated more frequently in the presence of the tendency for repetitiveness than in its absence. Therefore, the neutral propensity of DNA for duplication, which can also tend to generate repetitiveness in amino acid sequences, seems to be manifested primarily when the constraints on amino acid sequences are relatively weak, and yet may be positively contributing to generation of unevenness in modern proteins.

Increase in signal intensities on T1-weighted magnetic resonance images in asymptomatic manganese-exposed workers

OBJECTIVES

To clarify the clinical significance of increased signal intensities on T1 weighted magnetic resonance imaging (MRI) we performed a large-scale epidemiological study on asymptomatic manganese (Mn)-exposed workers with its focus on MRI.

METHODS

We randomly selected 121 male workers out of a total of 750 workers including Mn-exposed, non-exposed manual, and non-exposed clerical workers in the factories. We studied environmental and biological monitoring, neurological examination, and MRI.

RESULTS

The proportion of workers with increased signal intensities among the exposed, the non-exposed manual workers, and the non-exposed clerical workers was 46.1%, 18.8%, and 0%, respectively. Especially, 73.5% of the welders showed increased signal intensities. In no subject, were clinical signs of manganism observed. The pallidal index correlated with blood Mn concentration.

CONCLUSION

Increase in signal intensities on the T1-weighted image reflect recent exposure to Mn, but not necessarily manganism. At which increase of signal intensity, the progression of manganism from Mn exposure occurs, remains to be solved.

CXC and CC chemokine receptors on coronary and brain endothelia

BACKGROUND

Chemokine receptors on leukocytes play a key role in inflammation and HIV-1 infection. Chemokine receptors on endothelia may serve an important role in HIV-1 tissue invasion and angiogenesis.

MATERIALS AND METHODS

The expression of chemokine receptors in human brain microvascular endothelial cells (BMVEC) and coronary artery endothelial cells (CAEC) in vitro and cryostat sections of the heart tissue was determined by light and confocal microscopy and flow cytometry with monoclonal antibodies. Chemotaxis of endothelia by CC chemokines was evaluated in a transmigration assay.

RESULTS

In BMVEC, the chemokine receptors CCR3 and CXCR4 showed the strongest expression. CXCR4 was localized by confocal microscopy to both the cytoplasm and the plasma membrane of BMVEC. In CAEC, CXCR4 demonstrated a strong expression with predominantly periplasmic localization. CCR5 expression was detected both in BMVEC and CAEC but at a lower level. Human umbilical cord endothelial cells (HUVEC) expressed strongly CXCR4 but only weakly CCR3 and CCR5. Two additional CC chemokines, CCR2A and CCR4, were detected in BMVEC and CAEC by immunostaining. Immunocytochemistry of the heart tissues with monoclonal antibodies revealed a high expression of CXCR4 and CCR2A and a low expression of CCR3 and CCR5 on coronary vessel endothelia. Coronary endothelia showed in vitro a strong chemotactic response to the CC chemokines RANTES, MIP-1alpha, and MIP-1beta.

CONCLUSIONS

The endothelia isolated from the brain display strongly both the CCR3 and CXCR4 HIV-1 coreceptors, whereas the coronary endothelia express strongly only the CXCR4 coreceptor. CCR5 is expressed at a lower level in both endothelia. The differential display of CCR3 on the brain and coronary endothelia could be significant with respect to the differential susceptibility of the heart and the brain to HIV-1 invasion. In addition, CCR2A is strongly expressed in the heart endothelium. All of the above chemokine receptors could play a role in endothelial migration and repair.

A cytochrome P450 gene is differentially expressed in compatible and incompatible interactions between pepper (Capsicum annuum) and the anthracnose fungus, Colletotrichum gloeosporioides

The anthracnose fungus, Colletotrichum gloeosporioides, was previously shown to have an incompatible interaction with ripe-red fruit of pepper (Capsicum annuum). However, the fungus had a compatible interaction with unripe-mature-green fruit. Using mRNA differential display, we isolated and characterized a PepCYP gene expressed in the incompatible interaction. The PepCYP gene encodes a protein homologous to cytochrome P450 proteins containing a heme-binding domain. The expression level of PepCYP is higher in the incompatible interaction than in the compatible interaction, and then remains elevated in the incompatible interaction. In the compatible interaction, the expression of PepCYP is transient. The induction of PepCYP gene is up-regulated by wounding or jasmonic acid treatment during ripening. Analysis of PepCYP expression by in situ hybridization shows that the accumulation of PepCYP mRNA is localized in the epidermal cell layers, but not in the cortical cell layers. An examination of transverse sections of the fruits inoculated with the fungus shows that the fungus invades and colonizes the epidermal cell layers of the unripe fruit at 24 and 72 h after inoculation, respectively, but not those of the ripe fruit. These results suggest that the PepCYP gene product plays a role in the defense mechanism when the fungus invades and colonizes the epidermal cells of fruits in the incompatible interaction during the early fungal infection process.

Crystal structure of delta(5)-3-ketosteroid isomerase from Pseudomonas testosteroni in complex with equilenin settles the correct hydrogen bonding scheme for transition state stabilization

Delta(5)-3-Ketosteroid isomerase from Pseudomonas testosteroni has been intensively studied as a prototype to understand an enzyme-catalyzed allylic isomerization. Asp(38) (pK(a) approximately 4.7) was identified as the general base abstracting the steroid C4beta proton (pK(a) approximately 12.7) to form a dienolate intermediate. A key and common enigmatic issue involved in the proton abstraction is the question of how the energy required for the unfavorable proton transfer can be provided at the active site of the enzyme and/or how the thermodynamic barrier can be drastically reduced. Answering this question has been hindered by the existence of two differently proposed enzyme reaction mechanisms. The 2.26 A crystal structure of the enzyme in complex with a reaction intermediate analogue equilenin reveals clearly that both the Tyr(14) OH and Asp(99) COOH provide direct hydrogen bonds to the oxyanion of equilenin. The result negates the catalytic dyad mechanism in which Asp(99) donates the hydrogen bond to Tyr(14), which in turn is hydrogen bonded to the steroid. A theoretical calculation also favors the doubly hydrogen-bonded system over the dyad system. Proton nuclear magnetic resonance analyses of several mutant enzymes indicate that the Tyr(14) OH forms a low barrier hydrogen bond with the dienolic oxyanion of the intermediate.

Outer membrane protein A-promoted actin condensation of brain microvascular endothelial cells is required for Escherichia coli invasion

Escherichia coli is the most common gram-negative bacterium that causes meningitis during the neonatal period. We have previously shown that the entry of circulating E. coli organisms into the central nervous system is due to their ability to invade the blood-brain barrier, which is composed of a layer of brain microvascular endothelial cells (BMEC). In this report, we show by transmission electron microscopy that E. coli transmigrates through BMEC in an enclosed vacuole without intracellular multiplication. The microfilament-disrupting agents cytochalasin D and latrunculin A completely blocked E. coli invasion of BMEC. Cells treated with the microtubule inhibitors nocodazole, colchicine, vincristin, and vinblastine and the microtubule-stabilizing agent taxol also exhibited 50 to 60% inhibition of E. coli invasion. Confocal laser scanning fluorescence microscopy showed F-actin condensation associated with the invasive E. coli but no alterations in microtubule distribution. These results suggest that E. coli uses a microfilament-dependent phagocytosis-like endocytic mechanism for invasion of BMEC. Previously we showed that OmpA expression significantly enhances the E. coli invasion of BMEC. We therefore examined whether OmpA expression is related to the recruitment of F-actin. OmpA(+) E. coli induced the accumulation of actin in BMEC to a level similar to that induced by the parental strain, whereas OmpA(-) E. coli did not. Despite the presence of OmpA, a noninvasive E. coli isolate, however, did not show F-actin condensation. OmpA(+)-E. coli-associated condensation of F-actin was blocked by synthetic peptides corresponding to the N-terminal extracellular domains of OmpA as well as BMEC receptor analogues for OmpA, chitooligomers (GlcNAcbeta1-4GlcNAc oligomers). These findings suggest that OmpA interaction is critical for the expression or modulation of other bacterial proteins that will subsequently cause actin accumulation for the uptake of bacteria.

Expression of biliary antigen and its clinical significance in hepatocellular carcinoma

In order to classify the hepatocellular carcinomas (HCCs) which had diverse clinicopathologic characteristics, we divided HCCs into two groups according to the expression of biliary antigen on the basis of the hypothesis that the hepatocyte and biliary epithelial cell originate from the same precursor cell, and then we investigated the clinical and pathologic characteristics in the two groups. Forty HCC cases with no preoperative treatment and at least two-year follow-up data were selected among 202 cases of HCC files from 1991 to 1995. Expression of biliary antigen (AE1, cytokeratin 19), p53, AFP, and Ki-67 in the tumor tissue were assessed by immunohistochemistry. Positive cytokeratin 19 was noted in one case (2.5%); AE1 was detected in 40% of patients; p53 was overexpressed in 20% of patients; and AFP was detected in 45% of patients. No statistical difference between the biliary antigen positive group (16 cases) and the negative group (24 cases) were noted in terms of mean age, sex, presurgical serum AFP level, Child class, and tumor size. HBsAg positive rate was 66.7% for the biliary antigen (-) group and 93.8% for the biliary antigen (+) group with a statistically significant difference (p = 0.048). The number of cases for Edmonson-Steiner grade I/II and III/IV were 15 and 9 in the biliary antigen (-) group, and 4 and 12 in the biliary antigen (+) group, respectively, with a statistically significant difference (p = 0.024). The 1, 3 and 5-year disease-free survival rates were 69.7, 40.9 and 40.9% for the biliary antigen (-) group and 73.7, 39.1, 39.1% for the biliary antigen (+) group with no statistically significant difference. The 1, 3 and 5-year overall survival rates were 91.7, 73.8, 66.4% for the biliary antigen (-) group and 68.8, 34.4, 34.4% for the biliary antigen (+) group, with a significantly greater overall survival rate for the biliary antigen negative group (p = 0.045). Poor histopathological differentiation, a high HBsAg positive rate and poor overall survival rate were noted in the biliary antigen positive group and the differences were statistically significant. In conclusion, HCCs with positive biliary antigen, which originates from more primitive cells, is suggested to be more aggressive than HCCs with negative biliary antigen.

Coexpression of a defensin gene and a thionin-like via different signal transduction pathways in pepper and Colletotrichum gloeosporioides interactions

The anthracnose fungus, Colletotrichum gloeosporioides, interacts incompatibly with the ripe fruit of pepper (Capsicum annuum). It interacts compatibly with the unripe-mature fruit. We isolated a defensin gene, jl-l, and a thionin-like gene, PepThi, expressed in the incompatible interaction by using an mRNA differential display method. Both genes were developmentally regulated during fruit ripening, organ-specifically regulated, and differentially induced during the compatible and incompatible interactions. Expression of the PepThi gene was rapidly induced in the incompatible-ripe fruit upon fungal infection. The fungus-inducible PepThi gene is highly inducible only in the unripe fruit by salicylic acid. In both ripe and unripe fruit, it was induced by wounding, but not by jasmonic acid. Expression of the jl-l gene is enhanced by jasmonic acid in the unripe fruit but suppressed in the ripe fruit. These results suggest that both small and cysteine-rich protein genes are induced via different signal transduction pathways during fruit ripening to protect the reproductive organs against biotic and abiotic stresses.

Model dependence of the phylogenetic inference: relationship among carnivores, Perissodactyls and cetartiodactyls as inferred from mitochondrial genome sequences

Some previous analysis of mitochondrial proteins strongly support the Carnivora/Perissodactyla grouping excluding Cetartiodactyla (Artiodactyla + Cetacea) as an outgroup, but the support of the hypothesis remains equivocal from the analysis of several nuclear-encoded proteins. In order to evaluate the strength of the support by mitochondrial proteins, phylogenetic relationship among Carnivora, Perissodactyla, and Cetartiodactyla was estimated with the ML method by using the updated data set of the 12 mitochondrial proteins with several alternative models. The analyses demonstrate that the phylogenetic inference depends on the model used in the ML analysis; i.e., whether the site-heterogeneity is taken into account and whether the rate parameters are estimated for each individual proteins or for the concatenated sequences. Although the analysis of concatenated sequences strongly supports the Carnivora/Perissodactyla grouping, the total evaluation of the separate analyses of individual proteins, which approximates the data better than the concatenated analysis, gives only ambiguous results, and therefore it is concluded that more data are needed to resolve this trichotomy.

Escherichia coli binding to and invasion of brain microvascular endothelial cells derived from humans and rats of different ages

Escherichia coli meningitis commonly occurs in the neonatal period, but the basis of this age dependency is unclear. We have previously identified two types of E. coli-brain microvascular endothelial cell (BMEC) interactions contributing to E. coli traversal of the blood-brain barrier (i.e., binding and invasion). The present study examined whether the age dependency of E. coli meningitis stemmed from differences in the capacities of neonatal and adult BMECs to interact with E. coli. BMECs were isolated from rats of different ages (10 days, 20 days and 3 months) as well as from humans of different ages (fetuses, 4- to 7-year-old children, and a 35-year-old adult, and 60- to 85-year-old geriatrics). The bindings of E. coli to young and old rat BMECs were similar. Also, the abilities of E. coli to invade BMECs were similar for BMECs derived from young and old rats and from human fetuses, children, adults, and geriatrics. These findings suggest that the predominance of E. coli meningitis in neonates is not likely due to greater binding and invasion capacities of newborn compared to adult BMECs.

A systemic fetal inflammatory response and the development of bronchopulmonary dysplasia

OBJECTIVE

The purpose of this study was to test the hypothesis that a systemic fetal inflammatory response is a risk factor for the subsequent development of bronchopulmonary dysplasia in preterm neonates.

STUDY DESIGN

The relationship between interleukin 6 concentrations in umbilical cord plasma at birth and the occurrence of bronchopulmonary dysplasia was examined in 203 preterm births (25-34 weeks). Ninety-six patients underwent transabdominal amniocentesis within 5 days of birth. The relationship between umbilical cord plasma interleukin 6 concentration and bronchopulmonary dysplasia was compared with the relationship between amniotic fluid interleukin 6 concentration and bronchopulmonary dysplasia. Interleukin 6 was measured by specific immunoassay. Logistic regression was used for statistical analysis.

RESULTS

Bronchopulmonary dysplasia was diagnosed in 17% (34/203) of the infants. Neonates in whom bronchopulmonary dysplasia developed had a significantly higher median interleukin 6 concentration in umbilical cord plasma at birth than did those in whom bronchopulmonary dysplasia did not develop (median, 68.3 pg/mL and range, 0.3-6150.0 pg/mL vs median, 6.9 pg/mL and range 0-19,230.0 pg/mL; P <.001). This difference remained significant after adjustment for gestational age at birth (odds ratio, 4.2; 95% confidence interval, 1.6-11.2). Logistic regression analysis indicated that an elevated umbilical cord plasma interleukin 6 concentration was a better predictor of the development of bronchopulmonary dysplasia than was an elevated amniotic fluid interleukin 6 concentration (P <.005).

CONCLUSION

An elevated interleukin 6 concentration in umbilical cord plasma at birth is an independent risk factor for the development of bronchopulmonary dysplasia. These data support the concept that the injury responsible for bronchopulmonary dysplasia in a subset of neonates may begin before birth and is associated with the development of a fetal systemic inflammatory response, as determined by plasma concentrations of interleukin 6.

Backbone dynamics of the human CC chemokine eotaxin: fast motions, slow motions, and implications for receptor binding

Eotaxin is a member of the chemokine family of about 40 proteins that induce cell migration. Eotaxin binds the CC chemokine receptor CCR3 that is highly expressed by eosinophils, and it is considered important in the pathology of chronic respiratory disorders such as asthma. The high resolution structure of eotaxin is known. The 74 amino acid protein has two disulfide bridges and shows a typical chemokine fold comprised of a core of three antiparallel beta-strands and an overlying alpha-helix. In this paper, we report the backbone dynamics of eotaxin determined through 15N-T1, T2, and [1H]-15N nuclear Overhauser effect heteronuclear multidimensional NMR experiments. This is the first extensive study of the dynamics of a chemokine derived from 600, 500, and 300 MHz NMR field strengths. From the T1, T2, and NOE relaxation data, parameters that describe the internal motions of eotaxin were derived using the Lipari-Szabo model free analysis. The most ordered regions of the protein correspond to the known secondary structure elements. However, surrounding the core, the regions known to be functionally important in chemokines show a range of motions on varying timescales. These include extensive subnanosecond to picosecond motions in the N-terminus, C-terminus, and the N-loop succeeding the disulfides. Analysis of rotational diffusion anisotropy of eotaxin and chemical exchange terms at multiple fields also allowed the confident identification of slow conformational exchange through the "30s" loop, disulfides, and adjacent residues. In addition, we show that these motions may be attenuated in the dimeric form of a synthetic eotaxin. The structure and dynamical basis for eotaxin receptor binding is discussed in light of the dynamics data.

Isolation of a novel microorganism, pestalotia heterocornis, producing paclitaxel

Pestalotia heterocornis was isolated from soil collected in yew forest and was shown to produce paclitaxel in semisynthetic liquid media. The presence of paclitaxel in the fungal extract was confirmed by FAB mass spectrometry and NMR spectroscopy. The maximum yield of paclitaxel was 31 &mgr;g per liter. Optimal paclitaxel production occurred after 5-7 days in a 20-liter scale fermentation at 23 degrees C. These results indicate that P. heterocornis is an excellent candidate for consideration in fermentation technology. Copyright 1999 John Wiley & Sons, Inc.

Interleukin (IL)-5 downregulates tumor necrosis factor (TNF)-induced eotaxin messenger RNA (mRNA) expression in eosinophils. Induction of eotaxin mRNA by TNF and IL-5 in eosinophils

An eotaxin is a chemoattractant specific for eosinophils that are known to play a role in helminth infection and allergic responses. Although several cellular sources have been reported to produce eotaxin, it would be interesting to know whether eosinophils are able to produce their own eotaxin and participate in recruitment of themselves in response to inflammation. To this end, a cloned eotaxin complementary DNA was transcribed in vitro to use as a probe for detecting eotaxin messenger RNA (mRNA), and eotaxin protein levels were determined by enzyme-linked immunosorbent assay. Eotaxin mRNA was, as analyzed by in situ hybridization, rarely detectable in unstimulated eosinophils, but was strongly induced in eosinophils when stimulated with tumor necrosis factor (TNF). Interleukin (IL)-5, which is known to be a major factor of eosinophil survival in vivo and in vitro, was also able to induce a modest level of eotaxin mRNA but inhibited TNF-induced eotaxin mRNA expression in a dose-response manner. Dexamethasone inhibited TNF-induced eotaxin mRNA expression. This result was consistent with that from reverse transcription/polymerase chain reaction followed by Southern blot analysis. Unlike the little expression of eotaxin mRNA in the absence of stimuli, the measurement of eotaxin protein revealed that a considerable amount of eotaxin protein was constitutively produced in unstimulated eosinophils. Its expression was upregulated by TNF and IL-5 as well. However, the inhibitory effect of IL-5 on TNF-mediated eotaxin protein production was not as pronounced as that on eotaxin mRNA induction. Collectively, these data reflect the complex physiology of eosinophils in the expression of eotaxin gene upon the exposure to their survival and/or death factors.

Cereport (RMP-7) increases the permeability of human brain microvascular endothelial cell monolayers

PURPOSE

To study Cereport (RMP-7, bradykinin B2 agonist) effects on human brain microvascular endothelial cell (HBMEC) monolayer permeability.

METHODS

HBMEC grown on transwell membranes were exposed to Cereport. The monolayer permeability was determined with [14C]-inulin (MW. 5,200) and [3H]-dextran (MW. 70,000).

RESULTS

Cereport increased the HBMEC permeability to [14C]-inulin, but not to [3H]-dextran. The effect was transient, maximal at 15 min (i.e., 79.3% increase), and polarized to the basolateral membrane. An inverted U, dose-response curve was observed with active concentrations of Cereport from 0.01 to 0.5 nmol/L, the plateau maximal effect between 0.5 and 10 nmol/L, and loss of activity at the highest concentration, i.e., 20 nmol/L. Cyclic AMP-specific phosphodiesterase 3 (PDE3) inhibitor rolipram (10 micromol/L) abolished Cereport effects, while cGMP-specific PDE5 inhibitor, zaniprast (50 micromol/L) enhanced by 31% (p < 0.05) the effect of 0.1 nmolL Cereport. Unlabeled Cereport displaced [125I]-bradykinin and/or [125I]-Cereport from the basolateral side. There was no specific Cereport binding to the apical side.

CONCLUSIONS

Cereport exerts specific time, dose and size dependent actions on HMBEC monolayer that are restricted to the basolateral membrane. Its effects can be further modulated through changes in cAMP and cGMP second messenger systems.

Remodeling of the occupational medical examination program in South Korea

The South Korean government carried out reforms in the occupational medical examination program over a period of 2 years from 1997 to 1998 in a response to the discontent of workers, who had complained that occupational medical examinations were merely ritualistic and unproductive. The purposes of this manuscript are to describe the reason for the remodeling, with a historical review of the existing occupational medical examination program in South Korea, and to discuss the main issues involved in remodeling the program. The existing occupational medical examination program in South Korea was reviewed and criticized. The basic philosophy and the main issues in remodeling South Korea's occupational medical examination program were also discussed. In conclusion, the occupational medical examination program should not be conducted in a uniform manner according to legal regulations, but should be a part of overall occupational health services. Individual workplaces should be given the autonomy to perform medical examinations according to the characteristics of the workplace. An enabling approach based on the participation of labor and management should be taken into consideration.

The gene locus yijP contributes to Escherichia coli K1 invasion of brain microvascular endothelial cells

Most cases of Escherichia coli meningitis develop as a result of hematogenous spread, but it is not clear how circulating E. coli crosses the blood-brain barrier. A TnphoA mutant of E. coli K1 RS218 was shown to be significantly less invasive than its parent strain in bovine and human brain microvascular endothelial cells (BMEC), which constitute the blood-brain barrier. More importantly, traversal of the blood-brain barrier was significantly less with this mutant than with the parent strain in newborn rats with experimental hematogenous meningitis. A DNA segment containing the TnphoA insertion site was cloned from RS218, and the cloned DNA complemented the TnphoA mutant in invasion of BMEC. Nucleotide sequence revealed a near identity to that of a hypothetical yijP gene (also called f577) in the E. coli K-12 genome. Sequence analysis indicated that the E. coli K1 yijP gene likely encodes a 66. 6-kDa membrane protein. Deletion and complementation experiments indicated that the yijP gene was involved in E. coli K1 invasion of BMEC, i.e., the invasive ability of E. coli K1 was significantly reduced after yijP was deleted and was restored by complementation with a plasmid containing the yijP open reading frame. This is the first demonstration that the yijP gene locus plays a role in the pathogenesis of E. coli K1 meningitis.

Monoclonal antibodies to recombinant Der p 2, a major house dust mite allergen: specificity, epitope analysis and development of two-site capture ELISA

House dust mite allergens have been well established as sensitizing agents that are important in the induction of allergic diseases. In order to analyze epitopes of the allergen and to develop a quantitative method of the allergen exposure, monoclonal antibodies against a recombinant Der p 2 (rDer p 2), one of the major allergens of Dermatophagoides pteronyssinus, were produced. Four monoclonal antibodies produced were species-specific and did not cross-react to the D. farinae crude extract. Two of the monoclonal antibodies were found to be IgG1 and the others were IgM. For the analysis of epitopes, a Der p 2 cDNA encoding 126 amino acids (aa) was dissected into three fragments with several overlapping peptides. A (aa residues 1-49), B (44-93), and C fragment (84-126). Three monoclonal antibodies showed reactivities to the recombinant B fragment and to the full-length rDer p 2, but one monoclonal antibody reacted only with the full-length rDer p 2. Two-site capture ELISA was developed using two different monoclonal antibodies for quantitating Der p 2 in house dust. The sensitivity limit was 4 ng/ml with rDer p 2 and 8 micrograms/ml with the D. pteronyssinus crude extract. The result suggested that the assay using monoclonal antibodies against rDer p 2 could be useful for the environmental studies and for the standardization of mite allergen extracts.

Cisatracurium neuromuscular block at the adductor pollicis and the laryngeal adductor muscles in humans

We have compared the dose-response relationship (n = 30) and time course of neuromuscular block (n = 20) of cisatracurium at the laryngeal adductor and the adductor pollicis muscles. ED95 values for cisatracurium were 66.8 (95% confidence interval 61.3-72.3) micrograms kg-1 at the larynx and 45.2 (42.1-48.3) micrograms kg-1 at the adductor pollicis muscle (P < 0.0001). After administration of cisatracurium 0.1 mg kg-1, onset time was 2.7 (2.2-3.2) min at the larynx and 3.9 (3.0-4.8) min at the adductor pollicis (P < 0.0001). Time to 95% recovery of the first twitch of the TOF was 26.9 (20.1-33.7) min and 45.6 (39.7-51.5) min, respectively (P < 0.0001). We found that the laryngeal adductors were more resistant to the action of cisatracurium than the adductor pollicis muscle, but onset and recovery were faster at the larynx.