Serotypes and antimicrobial susceptibility in clinical isolates of Haemophilus influenzae from Korean children in prevaccination era

Fifty-five strains of Haemophilus influenzae recovered at a children's hospital in Korea from 1992 through 1997, were analyzed for serotype and antibiotic resistance. Antimicrobial susceptibility was tested by broth dilution method. Among the 55 strains, 26 were from normally sterile body fluids, of which 17 were from the immunocompetent children. Spectrum in the immunocompetent included meningitis (47%), bacteremic pneumonia (18%), and bacteremia without focus (35%). Three (12%) of 26 invasive infections were caused by non-type b: one type d and two type f. Nine of 29 non-sterile body fluid isolates belonged to one of encapsulted serotypes: four a, two c, one of each of b, d and e. Thirty two (58%) strains were resistant to ampicillin, and all of which produced beta-lactamase. All of the strains were highly susceptible to amoxicillin/clavulanate, cefixime, cefuroxime, azithromycin and ciprofloxacin, while 1 (2%), 7 (13%), 4 (7%) and 4 (7%) strains were intermediate to cefprozil, cefaclor, loracarbef, and clarithromycin, respectively. The serotype distribution of H. influenzae in Korean children is similar to those in developed countries before the introduction of Hib conjugate vaccine, and ampicillin resistance rate is among the highest published to date.

Three-year follow-up of women with the sole diagnosis of depressive personality disorder: subsequent development of dysthymia and major depression

OBJECTIVE

The authors sought to determine whether subjects with the sole diagnosis of depressive personality disorder are at higher risk for developing dysthymia and major depression than are healthy comparison subjects.

METHOD

Eighty-five women with depressive personality disorder who had no comorbid axis I or axis II disorders and 85 age-matched healthy comparison women were initially recruited and reinterviewed 3 years later to evaluate the cumulative incidence rate of dysthymia and major depression.

RESULTS

At the 3-year follow-up assessment, the women with depressive personality disorder had a significantly greater odds ratio for developing dysthymia than did the healthy comparison women. The difference in odds ratios for the development of major depression between women with and without depressive personality disorder did not reach statistical significance.

CONCLUSIONS

The present study, the first to determine the subsequent development of dysthymia and major depression in subjects with the sole diagnosis of depressive personality disorder, found that subjects with depressive personality disorder had a greater risk of developing dysthymia than did healthy comparison subjects at 3-year follow-up. Findings of the current study also suggest that depressive personality disorder may mediate the effects of a family history of axis I unipolar mood disorders.

Pulse amperometric detection of salt concentrations by flow injection analysis using ionodes

A sensitive novel approach of using an amperometric ion detector for the flow injection analysis of salts has been developed. The detection methodology is based on measuring the current associated with the transfer of ions across polarized microinterfaces between the aqueous sample solution and a 2-nitrophenyloctyl ether-poly(vinyl chloride) gel phase, referred to as ionodes. Different sodium salts of fluoride, chloride, bromide, nitrate, and sulfate were investigated. It was found that by employing an amperometric pulse detection mode and pure water as eluent, the detection limit of the ionode detector could be lowered to ppt level of salt concentrations under flowing conditions.

Detection of radiation-induced hydrocarbons and 2-alkylcyclobutanones in irradiated perilla seeds

The method consists of the extraction of fat from perilla seeds, separation of hydrocarbons and 2-alkylcyclobutanones with florisil column chromatography, and identification of hydrocarbons and 2-alkylcyclobutanones by gas chromatography-mass spectroscopy (GC-MS). Concentrations of hydrocarbons and 2-alkylcyclobutanones increased with the irradiation dose. The major hydrocarbons in the irradiated perilla seeds were 8-heptadecene and 1,7-hexadecadiene from oleic acid and 6,9-heptadecadiene and 1,7,10-hexadecatriene from linoleic acid. One of the 2-alkylcyclobutanones, 2-(5'-tetradecenyl)cyclobutanone, was found in the highest concentration in the irradiated perilla seeds. Radiation-induced hydrocarbons in the perilla seeds were detected at doses of 0.5 kGy and higher, and radiation-induced 2-alkylcyclobutanones were detected at doses of 1 kGy and higher. These compounds were not detected in nonirradiated perilla seeds.

Cu2+-catalyzed oxidative degradation of thyroglobulin

Thyroglobulin (Tg) was subjected to metal-catalyzed oxidation, and the oxidative degradation was analyzed by SDS-polyacrylamide gel electrophoresis under reducing conditions. In contrast to no effect of hydrogen peroxide (H2O2) alone on the Tg degradation, the inclusion of Cu2+ (30 microM), in combination with 2 mM H2O2, caused a remarkable degradation of Tg, time- and concentration-dependent. The action of Cu2+ was not mimicked by Fe2+, suggesting that Tg may interact selectively with Cu2+. A similar degradation of Tg was also observed with Cu2+/ascorbate system, and the concentration of Cu2+ (5-10 microM), in combination with ascorbate, required for the effective degradation was smaller than that of Cu2+ (10-30 microM) in combination with H2O2. In support of involvement of H2O2 in the Cu2+/ascorbate action, catalase expressed a complete protection. However, hydroxyl radical scavengers such as dimethylsulfoxide or mannitol failed to prevent the oxidation of Tg whereas phenolic compounds, which can interact with Cu2+, diminished the oxidative degradation, presumably consistent with the mechanism for Cu2+-catalyzed oxidation of protein. Moreover, the amount of carbonyl groups in Tg was increased as the concentration (3-100 microM) of Cu2+ was enhanced, while the formation of acid-soluble peptides was not remarkable in the presence of Cu2+ up to 200 microM. In further studies, Tg pretreated with heat or trichloroacetic acid seemed to be somewhat resistant to Cu2+-catalyzed oxidation, implying a possible involvement of protein conformation in the susceptibility to the oxidation. Based on these observations, it is proposed that Tg could be degraded non-enzymatically by Cu2+-catalyzed oxidation.

Expression of promyelocytic leukaemia protein in thyroid neoplasms

AIMS

Promyelocytic leukaemia protein (PML) is an oncoprotein involved in the pathogenesis of acute promyelocytic leukaemia and is localized in distinct PML nuclear bodies. Our previous observation of overexpression of the PML in hormone-sensitive normal tissues and malignant solid tumours, including the thyroid, led to this analysis of the PML expression in various thyroid neoplasms to characterize the importance of the PML in thyroid carcinogenesis.

METHODS AND RESULTS

Immunohistochemistry was performed on paraffin-embedded tissue samples from 106 thyroid neoplasms after antigen retrieval by microwave. Immunoblotting was done with fresh frozen tissues in a few tumours. The PML was strongly expressed in all papillary carcinomas in diffuse or ball-shaped patterns. In the follicular neoplasms, the PML expression was variable, but there was no significant difference between adenomas and carcinomas. In the medullary carcinomas, the PML expression was either not detectable or was lower than in non-neoplastic thyroids. Quantitatively different expression of the PML in various thyroid neoplasms was confirmed by immunoblotting.

CONCLUSION

A significant difference of the PML expression according to the type of thyroid neoplasms suggests that the PML is important in papillary thyroid carcinomas, and furthermore, that PML expression may be used in differential diagnosis of thyroid neoplasms.

Arrangement of the systemic and pulmonary venous components of the atrial chambers in hearts with isomeric atrial appendages

BACKGROUND

The morphological definition of atrial chambers, and the determination of atrial laterality, are based on analysis of the structure of the atrial appendages. The systemic and pulmonary venous connections to the heart, nonetheless, are important in the management of patients having isomeric appendages. In this study, therefore, we analysed the morphology of the postero-superior walls of the atrial chambers so as to provide evidence concerning the morphogenetic background of those hearts, and to improve operative management.

METHODS

We reviewed 15 autopsied specimens with isomeric right appendages, and 10 with isomeric left appendages, paying particular attention to the morphology of the systemic and pulmonary venous connections. The postero-superior walls of the atrial chambers can be made up of the atrial body, the systemic venous components, or the pulmonary venous component. We analysed the contributions made by each of these components.

RESULTS

The postero-superior walls of the atrial chambers were markedly variable, but could be grouped into five patterns. Bilaterally well-developed systemic venous components and absence of the pulmonary venous component within the hypoplastic atrial body were present in 9 hearts with extracardiac pulmonary venous connections in the setting of right isomerism. Bilaterally well-developed systemic venous components, and a hypoplastic pulmonary venous component within the hypoplastic atrial body, were present in 5 hearts with intracardiac pulmonary venous connections in right isomerism. Bilaterally well-developed systemic venous components, and a hypoplastic pulmonary venous component within the sizable atrial body, were present in 1 heart with an intracardiac pulmonary venous connection in right isomerism. A well-developed pulmonary venous component within the atrial body, and hypoplasia of one systemic venous component, were present in 7 hearts with left isomerism. A well-developed pulmonary venous component within the atrial body, and hypoplasia of bilateral systemic venous components, were present in 3 hearts with left isomerism.

CONCLUSIONS

The postero-superior walls of the atrial chambers in hearts with isomeric atrial appendages can be analysed on the basis of a compound structure made of bilateral systemic venous components, a central pulmonary venous component, and the body of the atrium. Hearts with isomeric right appendages have absence or hypoplasia of the pulmonary venous component, while hearts with isomeric left appendages have hypoplastic systemic venous components.

Six novel mutations of the fibrillin-1 gene in Korean patients with Marfan syndrome

BACKGROUND

Mutations in the FBN1 gene, encoding fibrillin-1, result in Marfan syndrome (MFS). According to previous reports, the mutations in FBN1 share certain characteristics in each family with variable penetrance and overlapping symptoms, even in the same genotype. In the present study, we report six novel mutations and evaluate the clinical significance of these nucleotide changes.

METHODS

To screen for nucleotide changes in all 65 exons of the FBN1 gene in 38 unrelated Korean patients, we performed polymerase chain reaction, single-strand conformational polymorphism (SSCP) and sequencing for the shift of the band in SSCP.

RESULTS

We identified six mutations: a 2253 del 7 b.p., N1043S, C1254S, L1421F, C1895R and S2662P.

CONCLUSIONS

These results suggest that many different mutations are responsible for MFS in the Korean population.

Hormonal regulation of sodium/sulfate co-transport in renal epithelial cells

Serum sulfate concentrations are elevated in infants, young children, and pregnant women due, at least in part, to increased renal sulfate reabsorption. Little is known about the effects of hormones, particularly those involved in growth, development, and pregnancy, on renal sulfate reabsorption. The objective of this investigation was to examine the effects of growth hormone (GH), insulin-like growth factor 1 (IGF-1), progesterone (PG), and 17beta-estradiol (EST) on renal sodium/sulfate co-transport. 35S-sulfate uptake was determined in Madin-Darby canine kidney (MDCK)/NaSi-1 cells (MDCK cells that have been stably transfected with rat sodium/sulfate co-transporter (NaSi-1) cDNA) and in opossum kidney (OK) cells. NaSi-1 mRNA was determined by RT-PCR and protein levels by ELISA. GH (0.1 nM) significantly increased the sodium/sulfate co-transport in MDCK/NaSi-1 cells up to 35%. IGF-1 induced a concentration-related stimulation of the sodium/sulfate co-transport with a maximal response observed at 1000 nM (59% increase). Sodium-dependent sulfate uptake was significantly increased when cells were preincubated with 10 nM PG, 10 nM EST, or 10 nM PG/10 nM EST up to 41%, 46%, or 39%, respectively. OK cells exhibited endogenous sodium-dependent sulfate transport; significantly increased sodium/sulfate co-transport was also observed in OK cells that were preincubated with GH, IGF-1, and PG/EST, although not with EST alone. The NaSi-1 mRNA and NaSi-1 protein levels were significantly increased in MDCK/NaSi-1 cells treated with 0.1 nM GH, 100 nM IGF-1, 10 nM PG, and/or 10 nM EST compared with control. These results suggest that the increased renal sulfate reabsorption that occurs in neonates, young and pregnant humans, and animals could be mediated by the increased steady-state levels of NaSi-1 mRNA produced by the higher plasma concentrations of GH, IGF-1, or PG/EST.

Long-term urinary toxicity after 3-dimensional conformal radiotherapy for prostate cancer in patients with prior history of transurethral resection

PURPOSE

To report on the long-term urinary morbidity among prostate cancer patients with a prior history of a transurethral resection of the prostate (TURP) treated with high-dose 3-dimensional conformal radiotherapy (3D-CRT).

METHODS AND MATERIALS

Between 1988 and 1997, 1100 patients with clinically localized prostate cancer were treated with 3D-CRT. Of these, 120 patients (8%) were identified as having had a prior TURP and are the subjects of this analysis. The median age was 71 years (range: 49-83 years). The clinical stages of the patients were T1c: 33 (28%); T2a: 38 (32%); T2b: 15 (13%); and T3: 34 (27%). Neoadjuvant androgen ablation therapy was given to 39 (33%). The median radiation dose prescribed to the planning target volume was 75.6 Gy (range: 64.8-81 Gy). The median elapsed time from TURP to initiation of 3D-CRT was 69 months (range: 4-360 months). The median follow-up time was 51 months (range: 18-109 months).

RESULTS

Five patients of the 120 with a prior history of TURP (4%) developed a urethral stricture after 3D-CRT which was corrected with dilatation. The 5-year actuarial likelihood of >/= Grade 2 late urinary toxicities was 9%. No Grade 4 urinary toxicities were observed in this group of patients. Among 110 patients who were completely continent of urine prior to 3D-CRT, 10 (9%) developed stress incontinence requiring 1 pad daily for protection or experienced occasional leakage (not requiring pad protection). The 5-year incidence of >/= Grade 1 stress incontinence was 18% in patients who developed acute >/= Grade 2 GU symptoms during the course of 3D-CRT compared to 7% for patients who experienced Grade 1 or no acute urinary symptoms (p = 0.05). The radiation dose (>/=75.6 Gy vs. <75.6 Gy), the number of prior TURP procedures, or the volume of resected tissue at the time of TURP had no significant impact on the long-term urinary morbidity outcome. A multivariate analysis demonstrated that the presence of Grade 2 acute urinary symptoms was the only predictor of >/= Grade 1 stress incontinence after 3D-CRT in this group of patients.

CONCLUSIONS

Despite prior TURP, the incidence of >/= Grade 3 urinary toxicities is low. Nevertheless, especially among patients with a prior history of TURP who experience Grade 2 acute urinary symptoms during radiation treatment, a higher risk of stress incontinence is observed.

p53 gene mutations in Bowen's disease in Koreans: clustering in exon 5 and multiple mutations

We analyzed the p53 protein expression and gene mutations to evaluate the role of ultraviolet radiation or other carcinogens, and possible racial differences in 17 samples from 12 Korean patients with Bowen's disease. A simple microdissection technique was used to collect the tumor cells selectively. p53 protein expression was found in eight of 17 (47%) samples. Abnormalities in polymerase chain reaction (PCR)-single-strand conformation polymorphism (SSCP) analysis were observed in 16 (94%) samples. A total of 14 missense mutations were detected in eight (47%) samples; 11 were clustered in exon 5 and the remaining three were located in exon 8. UV-like mutations were seen in five of 14 (36%) mutations, but no CC to TT transitions, UV-fingerprint mutations were observed. Multiple mutations were present in two cases and double mutation in a single case. Each lesion in multiple Bowen's disease showed different mutations and was suggested to be of different clonal origins. TP53-loss of heterozygosity (LOH) was detected in four out of 15 (27%) informative samples. Clustering of mutations in exon 5 suggests the role of another carcinogen in Koreans or Asians other than the UVR. Microdissection would increase the detection rate of the p53 gene mutations and LOH not only in skin cancer but also in precancerous lesions.

Differential expression of nicotinamide adenine dinucleotide phosphate-diaphorase in hypothalamic areas of obese Zucker rats

Several studies have suggested that the activity of nitric oxide synthase (NOS) may be involved in the regulation of food intake in the genetically obese Zucker rats. In the present study, we investigated the expression of NOS in various hypothalamic regions of obese and lean Zucker rats using nicotinamide adenine dinucleotide phosphate (NADPH)-diaphorase histochemistry. Obese Zucker rats showed significantly lower staining intensities of NADPH-diaphorase-positive neurons in the paraventricular nucleus (PVN), lateral hypothalamic area (LHA) and ventromedial hypothalamic nucleus (VMH) than lean Zucker rats did. The differences in staining intensities between obese and lean Zucker rats were large in both the PVN and LHA, but such differences were relatively small in the VMH.

Molecular cloning and expression of aminopeptidase A isoforms from rat hippocampus

The full-length cDNA encoding aminopeptidase A (APAL) was cloned from a rat hippocampus cDNA library. A short variant aminopeptidase A (APAS), produced by deletion, was also cloned. In the case of APAL, the longest open reading frame encodes 945 amino acid residues with a calculated molecular mass of 108 kDa, and the deduced amino acid sequence shows 76, 86 and 78% identity with its human, murine and porcine counterparts, respectively. Rat aminopeptidase A mRNAs were detected in the kidney, liver, heart and brain by Northern blot analysis. When overexpressed in COS-1 cells, APAL shows apparent aminopeptidase A activity, whereas APAS does not.

Penicillamine induced lupus-like syndrome: a case report

Several drugs have been suggested to cause lupus-like syndrome. However, penicillamine-induced lupus-like syndrome has only rarely been reported in patients with Wilson's disease. We describe a 6- year-old Taiwanese girl, with a diagnosis of Wilson's disease in November, 1997, who developed lupus-like syndrome 17 months after penicillamine treatment. After treatment with prednisolone and decrease in the dose of penicillamine, her symptoms subsided gradually. This is the first such case reported in a Taiwanese patient. Because the symptoms of drug-induced lupus (DIL) are nonspecific, subjective and variable, the diagnosis of DIL requires awareness of DIL-inducing potential of chronic medication.

A case of Dowling-Degos disease suggesting an evolutional sequence

We report a 47-year-old woman who presented with asymptomatic reticulate hyperpigmentations on the neck, lateral face, axillae, trunk, inguinal areas, and dorsa of both hands and feet. We thought it was an unusual case in the spectrum between the pole of Dowling-Degos disease (DDD) and that of reticulate acropigmentation of Kitamura (RAK). Another interesting point was that the biopsied specimens from the abdomen, neck, and axillary lesions showed somewhat different histopathologic features from typical DDD, suggesting an evolutional sequence. From these findings we suggest that a lichenoid inflammation may be responsible for the typical maculo-papular lesions of DDD.

Lactobacillus kimchii sp. nov., a new species from kimchi

A bacteriocin-producing lactic acid bacterium, which was isolated from the Korean fermented-vegetable food kimchi, was subjected to a polyphasic taxonomic study using phenotypic characterization and phylogenetic and genetic methods. This organism (MT-1077T) has phenotypic properties that are consistent with the description characterizing the genus Lactobacillus. Phylogenetic analysis based on 16S rDNA sequences showed clearly that strain MT-1077T is a member of the genus Lactobacillus. The closest phylogenetic relatives are Lactobacillus alimentarius KCTC 3593T and Lactobacillus farciminis LMG 9200T, with levels of 16S rDNA similarity of 98.4 and 98.2%, respectively. Levels of 16S rDNA similarity between strain MT-1077T and other Lactobacillus species were less than 93.0%. Differences in some phenotypic characteristics and DNA-DNA relatedness data indicated that strain MT-1077T should be distinguished from L. alimentarius KCTC 3593T and L. farciminis LMG 9200T. On the basis of the data presented, it is proposed that strain MT-1077T should be placed in the genus Lactobacillus as a new species, Lactobacillus kimchii sp. nov. The type strain of the new species is strain MT-1077T (= KCTC 8903PT = JCM 10707T).

Electronic resonance and symmetry in single-molecule inelastic electron tunneling

Inelastic electron tunneling spectroscopy and microscopy with a scanning tunneling microscope revealed two vibrational modes showing a decrease in conductance at +/-82.0 and +/-38.3 mV sample bias for single oxygen molecules chemisorbed on the fourfold hollow sites of Ag(110) surface at 13 K. The spatial distribution of the vibrational intensities exhibited pi(g)-orbital (perpendicular to surface) symmetry of O2 with the molecular axis along the [001] direction. These results are attributed to resonant inelastic electron tunneling.

Evidence for basolateral but not apical membrane localization of outwardly rectifying depolarization-induced Cl(-) channel in airway epithelia

The rat primary cultured-airway monolayer had been an excellent model for deciphering the ion channel after nystatin permeabilization of its basolateral or apical membrane (Hwang et al., 1996). After apical membrane permeabilization of rat primary cultured-airway monolayer, 4,4'-diisothiocyanatostilbene-2, 2'-disulfonic acid (DIDS)-sensitive outwardly rectifying depolarization-induced Cl(-) (BORDIC) currents were observed across the basolateral membrane in symmetrical NMG-Cl solution in this study. No significant Cl(-) current induced by the application of voltage clamping was observed across the apical membrane in symmetrical NMG-Cl solution after basolateral membrane permeabilization. The halide permeability sequence for BORDIC current was Br(-) = I(-) > Cl(-). BORDIC current was not affected by basolaterally applied bumetanide (0.5 mm). Basolateral DIDS (0.2 mm) but not apical DIDS inhibited CFTR mediated short-circuit current (I(sc)) in an intact monolayer of rat airway epithelia, a T84 human colonal epithelial cell line, and a Calu-3 human airway epithelial cell line. This is the first report showing that depolarization induced Cl(-) current is present on the basolateral membrane of airway epithelia.

Effects of dexamethasone on the pharmacokinetics of adriamycin after intravenous administration to rats

Adriamycin was metabolized to adriamycinol by the cytoplasmic aldo-keto reductase and adriamycin and adriamycinol were further metabolized to their deglycosylated aglycones, M3 and M4, respectively, by cytochrome P450. SKF-525A (a cytochrome P450 inhibitor) and dexamethasone (a cytochrome P450 inducer) were pretreated to rats. Adriamycin, 16 mg/kg, was infused over 1-min via the jugular vein of each rat. After pretreatment with SKF-525A, the area under the plasma concentration-time curve of adriamycin from time zero to the last measured time in plasma, 8 h (537 versus 155 microg x min/ml) was significantly greater, and the 24-h urinary excretion of M3 (1.65 versus 23.8 microg), and M3, M4, and their glucuronide and/or sulfate conjugates (33.7 versus 3.38 microg) were significantly smaller than those in control rats suggesting that the formation of M3 and M4 were inhibited by SKF-525A. After pretreatment with dexamethasone, the 24-h urinary excretion of M3 (94.5 versus 23.8 microg), M4 (8.43 versus 2.78 microg), and M3, M4, and their glucuronide and/or sulfate conjugates (116 versus 33.7 microg) were significantly greater than those in control rats, suggesting that the formation of M3 and M4 seemed to be induced by dexamethasone.

Guanidine hydrochloride induced reversible dissociation and denaturation of duck delta2-crystallin

The tetrameric delta2-crystallin from duck lens exhibits a reversible dissociation-denaturation process in solutions containing guanidine hydrochloride (GdnHCl). Sigmoidal or biphasic curves for the dissociation/denaturation processes, obtained using different methods of structural analysis, as a function of GdnHCl concentration were not coincidental with each other. delta2-crystallin in 0.91 M GdnHCl existed primarily as a monomer, which had no endogenous argininosuccinate lyase activity. After dilution of the GdnHCl-treated protein, the monomers reassociated into tetramers with concomitant recovery of enzyme activity. The sigmoidal recovery of enzyme activity demonstrates a cooperative hysteretic reactivation process. When the concentration of GdnHCl was higher than 1.2 M, various partially unfolded soluble forms of delta2-crystallin were produced from the dissociated monomers as shown by size-exclusion chromatography. The formation of a partially unfolded intermediate during the dissociation-denaturation process is proposed.

First success of catalytic epoxidation of olefins by an electron-rich iron(III) porphyrin complex and H2O2: imidazole effect on the activation of H2O2 by iron porphyrin complexes in aprotic solvent

An electron-rich iron(III) porphyrin complex (meso-tetramesitylporphinato)iron(III) chloride [Fe(TMP)Cl], was found to catalyze the epoxidation of olefins by aqueous 30% H2O2 when the reaction was carried out in the presence of 5-chloro-1-methylimidazole (5-Cl-1-Melm) in aprotic solvent. Epoxides were the predominant products with trace amounts of allylic oxidation products, indicating that Fenton-type oxidation reactions were not involved in the olefin epoxidation reactions. cis-Stilbene was stereospecifically oxidized to cis-stilbene oxide without giving isomerized trans-stilbene oxide product, demonstrating that neither hydroperoxy radical (HOO*) nor oxoiron(IV) porphyrin [(TMP)FeIV=O] was responsible for the olefin epoxidations. We also found that the reactivities of other iron(III) porphyrin complexes such as (meso-tetrakis(2,6-dichlorophenyl)porphinato)iron(III) chloride [Fe(TDCPP)Cl], (meso-tetrakis(2,6-difluorophenyl)porphinato)iron(III) chloride [Fe(TDFPP)Cl], and (meso-tetrakis(pentafluorophenyl)porphinato)iron(III) chloride [Fe(TPFPP)CI] were significantly affected by the presence of the imidazole in the epoxidation of olefins by H2O2. These iron porphyrin complexes did not yield cyclohexene oxide in the epoxidation of cyclohexene by H2O2 in the absence of 5-Cl-1-MeIm in aprotic solvent; however, addition of 5-Cl-1-MeIm to the reaction solutions gave high yields of cyclohexene oxide with the formation of trace amounts of allylic oxidation products. We proposed, on the basis of the results of mechanistic studies, that the role of the imidazole is to decelerate the O-O bond cleavage of an iron(III) hydroperoxide porphyrin (or H2O2-iron(II) porphyrin adduct) and that the intermediate transfers its oxygen to olefins prior to the O-O bond cleavage.

Aroma-active compounds of miniature beefsteakplant (Mosla dianthera Maxim)

Volatile flavor compounds of miniature beefsteakplant (Mosla dianthera Maxim.) from Vietnam were analyzed through gas chromatography-mass spectrometry-olfactometry (GC-MS-O). Sixty-two compounds were identified by GC-MS. Of these, (+/-)-carvone and (+/-)-limonene were the most abundant, followed by (Z)-limonene oxide, beta-caryophyllene, and alpha-humulene. Twenty aroma-active compounds were detected by aroma extract dilution analysis conducted on two GC columns of different polarities (DB-5MS and DB-Wax). The most intense aroma-active compounds were linalool (floral/sweet/lemon), (-)-carvone (spearminty), and 1-octen-3-one (mushroom/earthy). Other predominant aroma-active compounds included (Z)-3-hexenol (grassy/leafy/metallic), (Z)-limonene oxide (lemon/floral), myrcene (plastic/sweet), (+)-limonene (orange/lemon), alpha-thujene (soy sauce/grassy), and (Z)-dihydrocarvone (spearminty/pepperminty). On the basis of the aroma characteristics and intensity, it was concluded that (-)-carvone was responsible for the characteristic aroma of miniature beefsteakplant.

Rapid discriminatory detection of genes coding for SHV beta-lactamases by ligase chain reaction

Ligase chain reaction (LCR) is a recently developed technique that employs a thermostable ligase and allows for the discrimination of DNA sequences differing in only a single base pair. The method has been adapted and applied to differentiation of bla(SHV) genes. We have developed an LCR typing method to characterize point mutations in genes for SHV-derived extended-spectrum beta-lactamases with four different sets of biotinylated LCR primers. To evaluate the applicability of the current technique, we tested seven Escherichia coli strains producing SHV-1, SHV-2, SHV-2a, SHV-3, SHV-4, SHV-5, and SHV-12. With the LCR typing, seven SHV genes can be distinguished according to their incorporating point mutations. In an attempt to characterize SHV beta-lactamases by LCR typing in clinical isolates, 46 strains carrying bla(SHV) genes (32 Klebsiella pneumoniae, 10 Enterobacter cloacae, and 4 E. coli) were subjected to antibiotic susceptibility testing, isoelectric focusing, and LCR typing. LCR typing allowed the characterization of beta-lactamases, and genotypes obtained by LCR typing were in accordance with phenotypes such as antibiotic resistance profile and pI value of beta-lactamase. Therefore, we concluded that LCR typing may permit defining the SHV families with simplicity and reliability and can be applied to the detailed characterization and molecular epidemiology of SHV-type beta-lactamases.

Role of azaamino acid residue in beta-turn formation and stability in designed peptide

The structural perturbation induced by C(alpha)-->N(alpha) exchange in azaamino acid-containing peptides was predicted by ab initio calculation of the 6-31G* and 3-21G* levels. The global energy-minimum conformations for model compounds, For-azaXaa-NH2 (Xaa=Gly, Ala, Leu) appeared to be the beta-turn motif with a dihedral angle of phi= +/- 90 degrees, psi=0 degrees. This suggests that incorporation of the azaXaa residue into the i+2 position of designed peptides could stabilize the beta-turn structure. The model azaLeu-containing peptide, Boc-Phe-azaLeu-Ala-OMe, which is predicted to adopt a beta-turn conformation was designed and synthesized in order to experimentally elucidate the role of the azaamino acid residue. Its structural preference in organic solvents was investigated using 1H NMR, molecular modelling and IR spectroscopy. The temperature coefficients of amide protons, the characteristic NOE patterns, the restrained molecular dynamics simulation and IR spectroscopy defined the dihedral angles [ (phi i+1, psi i+1) (phi i+2, psi i+2)] of the Phe-azaLeu fragment in the model peptide, Boc-Phe-azaLeu-Ala-OMe, as [(-59 degrees, 127 degrees) (107 degrees, -4 degrees)]. This solution conformation supports a betaII-turn structural preference in azaLeu-containing peptides as predicted by the quantum chemical calculation. Therefore, intercalation of the azaamino acid residue into the i+2 position in synthetic peptides is expected to provide a stable beta-turn formation, and this could be utilized in the design of new peptidomimetics adopting a beta-turn scaffold.