Comparison of Microorganism Detection, Time to Positivity, and Time-Dependent Shift in Viable Bacterial Count from VersaTREK and BacT/ALERT 3D Blood Culture Systems

Rapid positive blood culture reporting allows early and appropriate treatment of severe infections to improve patient prognosis. This study evaluated performance of the VersaTREK system with gas pressure detection and tornado stirring method and the conventional BacT/ALERT 3D system. Time to positivity (TTP) of simulated blood cultures without whole blood using 17 ATCC strains was faster with VersaTREK than BacT/ALERT 3D, averaging 6.3 h in aerobic bottles and 12.7 hours in anaerobic bottles. In simulated blood cultures with whole blood using 53 clinical isolates, on average, VersaTREK was faster in aerobic bottles by 6.5 h but slower in anaerobic bottles by 3.8 h. Fifty of 53 simulated blood cultures with whole blood (94%) showed fastest TTP with VersaTREK. TTP of VersaTREK for anaerobic bacteria Bacteroides fragilis and Clostridium perfringens, Helicobacter cinaedi, and Candida glabrata was fast, and viable bacteria numbers in bottles using the Miles and Misra method increased quickly.

Modulating effects of oral administration of Lycii Fructus extracts on UVB‑induced skin erythema: A Randomized, placebo‑controlled study

Severe UV exposure induces skin inflammation, causing erythema. Lycii Fructus (Lycium barbarum and Lycium chinense) is a potential antioxidant agent with a high content of polyphenols, including rutin and chlorogenic acid. This study examined the effects of Lycii Fructus extract (LFE) on UVB-induced skin erythema in humans. Healthy volunteers were randomly assigned to one of two groups and received UVB irradiation at 1.5 minimal erythemal dose (MED) on day 0 at three designated sites on their backs, and the skin color was measured until day 7. After an 8-week treatment with LFE (900 mg/day) or placebo, UVB irradiation (l.5 MED) was applied again at different sites on day 63. Skin color was continuously measured in each group until day 69. LFE tablet administration for 8 weeks significantly inhibited UVB-induced erythema formation and increased the MED by 13%. Erythema formation peaked on the first day after UVB irradiation, but gradually dissipated over the next several days. LFE tended to accelerate erythema disappearance. To determine the polyphenol responsible for the protection against UVB-induced skin damage, the effects of LFE-derived polyphenols and their metabolites on UVB-induced cytotoxicity were examined in vitro. The major intestinal metabolite of rutin and LFE significantly attenuated phototoxicity and in human keratinocyte HaCaT cells. Quercetin enhanced intracellular glutathione levels in HaCaT cells, even though LFE did not increase it. Together, the results showed that LFE inhibited erythema formation and accelerated erythema dissipation, possibly through its direct antioxidative action.

Correlation of Strain Classification with IR Biotyper and Molecular Epidemiological Method of Pseudomonas aeruginosa

INTRODUCTION

From 2018, IR Biotyper (IRBT; Bruker Daltonik GmbH, Germany) based on the Fourier transform infrared spectrophotometer has begun to be introduced as a new strain classification method in the field of clinical microbiological examination. We compared it with molecular epidemiology method to evaluate the usefulness of strain classification by IRBT.

METHOD

Homology of strain classification with molecular epidemiology method (Multilocus Sequencing Typing; MLST and PCR-based ORF Typing; POT) for 48 strains of Pseudomonas aeruginosa with different detection times from multiple institutions to evaluate the accuracy of IRBT was compared.

RESULTS

IRBT used "KBM" SCD agar medium for preculture and was classified into 12 types when classified by Cut-off value 0.181, 8 types by MLST, and 13 types by POT. In the Adjusted Wallace between IRBT and molecular epidemiology method, MLST was 0.458 (95% CI; 0.295 to 0.620) and POT was 0.330 (95% CI; 0.135 to 0.525), indicating a discrepancy in strain classification.

CONCLUSION

No correlation was found between IRBT and the classification results by the molecular epidemiology method. In the molecular epidemiology method, strains are classified by matching only specific gene regions, but IRBT irradiates a sample with an infrared laser and classifies the strains according to the difference in absorption spectrum according to the molecular structure, so the measurement principle is different. When classifying strains by IRBT, it is desirable to grasp the clinical information of the detected strains and to target multiple strains isolated at the same facility at the same time.

[A Case of Fungalemia that Detected the Mucor circinelloides by Versa TREK]

Man in his 80s. In March 20XX, the level of consciousness decreased at the admission facility, and he was transported as an emergency case. He was diagnosed as aspiration pneumonia, septic shock due to cholecystitis, and DIC, and was hospitalized for medical treatment. During the course of hospitalization, aspiration pneumonia continued to improve and worsen, but in January 20XX＋3, a fever of 38.7°C occurred, and Mucor circinelloides was detected in the blood culture collected at this time. In sputum 7 days before the blood culture was submitted, an image of suspicious zygomycosis was confirmed by Gram stain, so the patient was diagnosed with Mucor disease and started administration of amphotericin B. After that, the condition was temporarily stable, but due to recurrence of aspiration pneumonia and renal damage, he died 19 days after the start of amphotericin B administration. It is difficult to detect Mucor spp. in blood culture, however in this case, it was detected by the blood culture device; Versa TREK (Thermo Fisher Scientific K.K. Tokyo, Japan).

3,5,7,3',4'-Pentamethoxyflavone Enhances the Barrier Function through Transcriptional Regulation of the Tight Junction in Human Intestinal Caco-2 Cells

The intestinal tight junction (TJ) barrier plays a pivotal role in the regulation of intestinal homeostasis. This study investigated the effects of 3,5,7,3',4'-pentamethoxyflavone (PMF), a major polymethoxyflavone found in black ginger, on TJ barrier regulation using intestinal Caco-2 cells. PMF treatment enhanced the TJ barrier integrity in Caco-2 cells, indicated by increased transepithelial electrical resistance (control, 1261 ± 36 Ω·cm²; 100 μM PMF, 1383 ± 55 Ω·cm² at 48 h, p < 0.05) and decreased permeability to fluorescein-conjugated dextran (control, 24.2 ± 1.8 pmol/(cm² × h); 100 μM PMF, 18.6 ± 1.0 pmol/(cm² × h), p < 0.05). Immunoblot analysis revealed that PMF increased the cytoskeletal association and cellular expression of the TJ proteins, zonula occludens-1, claudin-3, and claudin-4 (e.g., occludin; control, 1.00 ± 0.2; 100 μM PMF, 3.69 ± 0.86 at 48 h, p < 0.05). Quantitative reverse transcriptase-polymerase chain reaction analysis and a luciferase promoter assay showed that PMF enhanced the transcription of occludin, claudin-3, and claudin-4. The promoter assay with site-directed mutagenesis indicated that PMF-induced occludin and claudin-3 transcription was mediated by transcription factors, KLF5 and EGR1, respectively, while PMF activated claudin-4 transcription through GATA1 and AP1. Taken together, the transcriptional regulation of TJ proteins is involved in PMF-mediated promotion of the intestinal barrier in vitro.

Development of a real-time neutron beam detector for boron neutron capture therapy using a thin silicon sensor

We have developed a new real-time neutron detector, which is able to measure a direct neutron beam of boron neutron capture therapy. The detector consists of both a 40-μm-thick pn diode and around 0.09-μm-thick LiF neutron converter. Experimental results indicate that this neutron detector can measure neutron flux up to 1 × 10⁹ (cm^-2 s^-1), separately from gamma rays around 500 mGy/h. The measured depth distribution of neutron flux in an acrylic block is in agreement with the activation results of gold.

A mutation of the β-domain in POU1F1 causes pituitary deficiency due to dominant PIT-1β expression

BACKGROUND

POU1F1 encodes both PIT-1α, which plays pivotal roles in pituitary development and GH, PRL and TSHB expression, and the alternatively spliced isoform PIT-1β, which contains an insertion of 26-amino acids (β-domain) in the transactivation domain of PIT-1α due to the use of an alternative splice acceptor at the end of the first intron. PIT-1β is expressed at much lower levels than PIT-1α and represses endogenous PIT-1α transcriptional activity. Although POU1F1 mutations lead to combined pituitary hormone deficiency (CPHD), no patients with β-domain mutations have been reported.

RESULTS

Here, we report that a three-generation family exhibited different degrees of CPHD, including growth hormone deficiency with intrafamilial variability of prolactin/TSH insufficiency and unexpected prolactinoma occurrence. The CPHD was due to a novel POU1F1 heterozygous variant (c.143-69T>G) in intron 1 of PIT-1α (RefSeq number NM_000306) or as c.152T>G (p.Ile51Ser) in exon 2 of PIT-1β (NM_001122757). Gene splicing experiments showed that this mutation yielded the PIT-1β transcript without other transcripts. The lymphocyte PIT-1β mRNA expression was significantly higher in the patients with the heterozygous mutation than a control. A luciferase reporter assay revealed that the PIT-1β-Ile51Ser mutant repressed PIT-1α and abolished transactivation capacity for the rat prolactin promoter in GH3 pituitary cells.

CONCLUSIONS

We describe, for the first time, that the PIT-1β mutation can cause CPHD through a novel genetic mechanism, such as PIT-1β overexpression, and that POU1F1 mutation might be associated with a prolactinoma. Analysis of new patients and long-term follow-up are needed to clarify the characteristics of PIT-1β mutations.

Oral Supplementation of Collagen Peptides Improves Skin Hydration by Increasing the Natural Moisturizing Factor Content in the Stratum Corneum: A Randomized, Double-Blind, Placebo-Controlled Clinical Trial

INTRODUCTION

We aimed to investigate the effect of orally ingested collagen peptides (CPs) on skin condition and elucidate their mechanism of action.

METHODS

A randomized, placebo-controlled, double-blind trial was conducted in 99 healthy Japanese women, aged 35-50 years. The subjects were randomized into 3 groups (33 subjects/group) to receive 1 or 5 g of CP or placebo once daily for 12 weeks. Skin water content, transepidermal water loss (TEWL), skin elasticity, and skin thickness were evaluated before treatment and after 4, 8, and 12 weeks of treatment. The level of natural moisturizing factor (NMF) constituents in the stratum corneum (SC) was quantified before treatment and after 12 weeks of treatment.

RESULTS

Oral ingestion of CP increased the water content in the SC and epidermis and decreased TEWL. Furthermore, the NMF level in the SC was increased. However, skin elasticity and skin thickness remained unchanged.

CONCLUSIONS

The improvement in skin water content following the oral ingestion of CP can be attributed to an increase in the level of NMF in the SC.

TRIAL REGISTRATION

UMIN000030375 (retrospectively registered).

Novel strategy of rapid typing of Shiga toxin-producing Escherichia coli using MALDI Biotyper and ClinProTools analysis

INTRODUCTION

Rapid detection of Shiga toxin-producing Escherichia coli (STEC) is essential. Matrix-assisted laser-desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) allows rapid, accurate, and low-cost microbial identification. We aimed to examine the discrimination ability of MALDI Biotyper (Bruker Daltonics) between STEC and non-STEC.

METHODS

In total, 234 strains (79 STEC strains and 155 non-STEC strains) isolated from stool between 2009 and 2014 were measured by MALDI Biotyper and mass spectra of 2000-20,000 m/z were analyzed with ClinProTools (Bruker Daltonics). Eighty-three strains were randomly extracted to produce STEC detection models using 3 algorithms, and 151 strains were used as validation samples to verify STEC detection performance and discrimination performance of Shiga toxins with the STEC detection models.

RESULTS

The STEC detection model with Quick Classifier (QC) algorithm was the most sensitive: sensitivity, 84.1% (37/44); specificity, 94.4% (101/107). Discrimination between STEC and non-STEC was excellent, but individual discrimination of Shiga toxins was not possible.

CONCLUSION

MALDI Biotyper may be a useful rapid diagnostic method for STEC infection.

Single-Domain and Atomically Flat Surface of κ-Ga2O3 Thin Films on FZ-Grown ε-GaFeO3 Substrates via Step-Flow Growth Mode

Herein, single-domain κ-Ga₂O₃ thin films were grown on FZ-grown ε-GaFeO₃ substrates via a step-flow growth mode. The ε-GaFeO₃ possessing the same crystal structure and similar lattice parameters as those of the orthorhombic κ-Ga₂O₃ facilitated the growth of κ-Ga₂O₃ thin films, as observed by the X-ray diffraction (XRD) analysis. Furthermore, the surface morphologies of the κ-Ga₂O₃ thin films exhibited a step-terrace and atomically flat structure. XRD φ-scan and transmission electron microscopy with selected area electron diffraction revealed that there is no occurrence of in-plane rotational domains in the κ-Ga₂O₃ thin films on ε-GaFeO₃ substrates and that the κ-Ga₂O₃ thin film comprised a single domain. TEM analysis revealed that there were no clear dislocations in the observation area. Moreover, high-resolution TEM observation showed that the atomic arrangements of the film and the substrate were continuous without the presence of an intermediate layer along the growth direction and were well-aligned in the in-plane direction.

A 34-year-old Japanese patient exhibiting NBAS deficiency with a novel mutation and extended phenotypic variation

Biallelic neuroblastoma amplified sequence (NBAS) gene mutations have recently been identified to cause a reduction in its protein expression and a broad phenotypic spectrum, from isolated short stature, optic nerve atrophy, and Pelger-Huët anomaly (SOPH) syndrome or infantile liver failure syndrome 2 to a combined, multi-systemic disease including skeletal dysplasia and immunological and neurological abnormalities. Herein, we report a 34-year-old patient with a range of phenotypes for NBAS deficiency due to compound heterozygous variants; one is a SOPH-specific variant, p.Arg1914His, and the other is a novel splice site variant, c.6433-2A>G. The patient experienced recurrent acute liver failure until early childhood. Hypogammaglobulinemia, a decrease in natural killer cells, and optic nerve atrophy were evident from infancy to childhood. In adulthood, the patient exhibited novel phenotypic features such as hepatic cirrhosis complicated by portal hypertension and autoimmune hemolytic anemia. The patient also suffered from childhood-onset insulin-requiring diabetes with progressive beta cell dysfunction. The patient had severe short stature and exhibited dysmorphic features compatible with SOPH, intellectual disability, and epilepsy. NBAS protein expression in the patient's fibroblasts was severely low. RNA expression analysis for the c.6433-2A>G variant showed that this variant activated two cryptic splice sites in intron 49 and exon 50, for which the predicted consequences at the protein level were an in-frame deletion/insertion, p.(Ile2199_Asn2202delins16), and a premature termination codon, p.(Ile2199Tyrfs*17), respectively. These findings indicate that NBAS deficiency is a multi-systemic progressive disease. The results of this study extend the spectrum of clinical and genetic findings related to NBAS deficiency.

Accurate identification of Escherichia albertii by matrix-assisted laser desorption ionization-time of flight mass spectrometry

A specific identification protocol for Escherichia albertii by using a MALDI-TOF/MS method was developed. For this purpose, a novel database was established which can differentiate E. albertii from E. coli by combining the mass spectra obtained from 58 E. albertii and 36 E. coli strains.

Oral intake of lingonberry and amla fruit extract improves skin conditions in healthy female subjects: A randomized, double-blind, placebo-controlled clinical trial

In this study, we examined the effect of ingestion of lingonberry and amla fruit extract (LAE) on several human skin conditions. To conduct a randomized, double-blinded, placebo-controlled study, we randomly divided 99 healthy female subjects into three groups; the first group received a drink containing 25 mg of lingonberry extract and 30 mg of amla fruit extract; the second group received a drink containing double the volume of extracts received by the first group; and the third group received a placebo drink. Each participant drank 50 mL of their assigned drink once daily for 12 weeks. The primary endpoint was skin elasticity, and the secondary endpoints included skin thickness, stratum corneum water content, and degree of wrinkles around the eyes. After 12 weeks of LAE drink intake, skin elasticity showed significant, dose-dependent improvements (P < 0.01). Skin thickness, stratum corneum water content, and the degree of wrinkles also significantly improved (P < 0.001) in a dose-dependent manner. The improvements in skin elasticity and thickness, as well as in the stratum corneum water content and the degree of wrinkles, observed upon oral intake of LAE indicate that LAE may be considered a candidate anti-aging agent for preventing skin weakening.

Development of a novel matrix-assisted laser desorption/ionization time-of-flight mass spectrum (MALDI-TOF-MS)-based typing method to identify meticillin-resistant Staphylococcus aureus clones

BACKGROUND

Mass spectrum analysis enables species- and subspecies-level identification, and can be used as an epidemiological tool in outbreak management. However, its reliability at clonal level has yet to be established.

AIM

To establish a matrix-assisted laser desorption/ionization time-of-flight mass-spectrum-based method that enables bacterial clone identification with accuracy equivalent to pulsed-field gel electrophoresis/phage open-reading frame typing (PFGE/POT).

METHODS

Meticillin-resistant Staphylococcus aureus (MRSA) was used in this study. Mass spectra were obtained from a standard strain of S. aureus (ATCC29213) and 57 clinically isolated strains, categorized according to POT. Peaks associated with MRSA clone identification (N = 67) were extracted. Based on this peak information, the feasibility of MRSA clone identification was examined by cluster analysis.

FINDINGS

In addition to the 58 strains used for peak extraction, mass spectrum analysis of 24 clinically isolated outbreak strains revealed that peak data could be used for successful identification of clones. These typing results were fully consistent with the PFGE and POT results.

CONCLUSION

This novel method enables simple and rapid typing with accuracy equivalent to PFGE/POT. This method would be suited to rapid outbreak analysis, offering accurate information to combat infectious diseases.

Transdermal absorption of natural progesterone from alcoholic gel formulations with hydrophilic surfactant

OBJECTIVES

The aim of this study was to evaluate the in vitro skin permeation and in vivo transdermal absorption of natural progesterone (Prog) from alcoholic gel-based transdermal formulations containing Prog dissolved stably at a concentration of 3%.

METHODS

3% Prog dissolved gel formulations were prepared containing with water, ethanol, 1,3-butylene glycol, carboxyvinylpolymer, diisopropanolamine, polyoxyethylene (2) oleylether and benzyl alcohol. The gel formulations added different hydrophilic surfactants and isopropyl myristate or propylene glycol dicaprylate (PGDC) as oily solvents were applied in vitro permeation study through excised rat skin on unocclusive condition. The gel formulations added polyoxyethylene (20) oleylether (Oleth-20) as hydrophilic surfactant and PGDC were applied in vivo single- and repeated-dose transdermal absorption study of rat on unocclusive condition.

RESULTS

The results of evaluation of the gel formulations by an in vitro skin permeation study revealed a high flux of Prog from the formulation containing Oleth-20 and Oleth-20 with PGDC. The results of single and repeated in vivo transdermal absorption studies confirmed that good plasma levels of Prog were achieved and maintained by Oleth-20 and PGDC containing gel formulation.

CONCLUSIONS

The Oleth-20 and PGDC containing ethanolic gel formulation seemed to have the ability to maintain a high activity of Prog and high diffusivity or solubility of Prog in the epidermis on the practical formulation application.

Dental caries area of rat molar expanded by cigarette smoke exposure

OBJECTIVES

Passive smoking is the involuntary inhalation of cigarette smoke (CS) and has an adverse impact on oral health. We examined the effect of CS exposure on caries risk and experimental dental caries.

METHODS

Experimental dental caries was induced in rat maxillary molars which were inoculated orally with Streptococcus mutans MT8148 and maintained on a cariogenic diet (diet 2000) and high sucrose water during the experimental period. CS-exposed rats were intermittently housed in an animal chamber with whole-body exposure to CS until killed. Whole saliva was collected before CS exposure (day 0) and for 30 days after the start of CS exposure. Saliva secretion was stimulated by administration of isoproterenol and pilocarpine after anesthesia. Maxillary molars were harvested on day 31.

RESULTS

The increase in body weight of the CS-exposed rats was less than that of the control rats. Salivary flow rate, concentration of S. mutans in the stimulated saliva and caries activity score did not significantly differ between 0 and 30 days after the start of CS exposure. Histological examination of the caries-affected area on maxillary molars 30 days after CS exposure showed expansion compared to control rats. In the electron probe microanalysis, no differences were observed between the mineral components of the CS-exposed teeth and the control teeth.

CONCLUSION

These results suggest that CS exposure expands the caries-affected area in the maxillary molars of the rat.

Dietary glucosylceramide enhances cornified envelope formation via transglutaminase expression and involucrin production

In this study, we investigated whether dietary glucosylceramide (GlcCer) and its metabolite sphingoid bases, sphingosine (SS), phytosphingosine (PS), sphingadienine (SD) and 4-hydroxysphingenine (4HS), influence cornified envelope (CE) formation. CE is formed during terminal differentiation of the epidermis through crosslinking of specific precursor proteins by transglutaminases (TGases), and is essential for the skin's barrier function. Oral administration of GlcCer (0.25 mg/day) for 14 consecutive days dramatically reduced transepidermal water loss, an indicator of the skin barrier condition, in hairless mice with barrier perturbation induced by single-dose ultraviolet B (UVB) irradiation. The GlcCer treatment also increased the level of TGase-1 mRNA in UVB-irradiated murine epidermis approximately 1.6-fold compared with the control. Further, all four sphingoid bases at 1 μM concentration enhanced CE formation of cultured normal human keratinocyte cells. Among them, SS, PS and SD, but not 4HS, stimulated production of involucrin, one of the CE major precursor proteins. SD increased the expression of TGase-1 mRNA, while SS increased the expression of TGase-3 mRNA. These results indicate that the skin barrier improvement induced by oral GlcCer treatment might be at least partly due to a reinforcement of CE formation in the epidermis mediated by sphingoid bases metabolically derived from GlcCer.

Tem Study of Cvd‐Grown Bi‐Sr‐Ca‐Cu‐0 Thin Films on (001) Mgo Substrates

CVD‐grown Bi‐Sr‐Ca‐Cu‐0 thin films on (OOl)MgO with T at 110 K have been investigated by transmission electron microscopy. The films are found to consist of large domains oriented along the c‐axis, with diameters of 15‐100 um. These domains exhibit incommensurate superstructures along the fa‐axis. In addition, we have observed similar superstructure spots in two equivalent directions normal to each other. It has also been found that the interface between the thin film and the substrate is very abrupt. Five different perovskite‐related layers along the c‐axis with different thickness are present. In the thin film, 80K phases are dominant and 110 K phases are less likely. Three other phases are very rarely observed. Furthermore, boundaries where the layered structure is different on both sides are often found.

Cellular locations of proteinases and association with vesicles in Porphyromonas gingivalis

We found that locations of arginine-specific gingipain (RGP) in the cellular fractions in the crude extract, envelope, vesicles, and culture supernatants were 48%, 16%, 17%, and 31%, respectively, and the corresponding values of lysine-specific gingipain (KGP) were 47%, 10%, 7%, and 36%, respectively. Although the molecular mass of RGP in the culture supernatant had been determined as 43 kDa, and that of KGP had been as 48 kDa, molecular masses of both proteinases solubilized from the vesicles were estimated to be over 1,500 kDa, since they eluted in the void volume of the column in the gel filtration on Sephacryl S-300. There was no reduction of molecular size by the following treatment with SDS, high-concentration NaCl, or urea. Interestingly, the occurrence of the macromolecular forms could not observed in other enzymes tested such as monopeptidyl, dipeptidyl, and tripeptidyl peptidases, as well as alkaline phosphatase. Therefore, occurrence of the macromolecular forms may be restricted to the proteinases. When the vesicle and culture supernatants containing free RGP and KGP were mixed and incubated, neither RGP nor KGP seemed to bind to vesicles. RGP bound to the vesicle was found to be more stable to heat treatment than the free form, suggesting that association of RGP with the vesicle caused heat stability of this enzyme.

Distribution and metabolism of sphingosine in skin after oral administration to mice

In this study, (3)H- or (13)C(2),D(2)-sphingosine (SPH) was orally administered to mice to assess absorption, mass balance, tissue distribution, and metabolites in the skin. The blood concentration of (3)H-SPH showed a Tmax of 10.7 hr. The radioactivity in the skin reached 763.4 ng eq./g tissue at 12 hr, and decreased to 181.7 ng eq./g tissue at 168 hr. The concentration of radioactivity at 12 hr was 577.6 and 100.7 ng eq./g tissue in the dermis and epidermis, respectively. Thereafter, the dermis concentration decreased to 158.5 ng eq./g tissue, while the epidermis concentration increased to 298.8 ng eq./g tissue, suggesting that radioactivity moves from the dermis to the epidermis. Unchanged SPH along with lipophilic metabolites was detected in the skin of mice exposed orally to (3)H- or (13)C(2),D(2)-SPH. Moreover, in an in vitro study using human skin keratinocytes, a (13)C(2),D(2)-SPH-treatment resulted in the intracellular production of glucosylceramides (GlcCer) and ceramides (Cer) containing labeled-SPH. These results indicate the followings: first, that SPH is absorbed through the digestive tract and distributed to the skin; second, it is transferred from the dermis to the epidermis; and third, SPH is partly distributed to the skin in an unchanged form, and some of the distributed compounds are converted into GlcCer and Cer by biosynthesis.

Hemoglobin binding activity and hemoglobin-binding protein of Prevotella nigrescens

Prevotella nigrescens, lacking siderophores was found to bind to the hemoproteins. The binding was observed also in the envelope which was prepared by sonication of the cell. The binding occurred in the pH-dependent manner; the binding was observed below neutral pHs of the incubation mixtures but only slightly observed in the neutral and alkaline pHs. Furthermore, hemoglobin bound to the envelope was dissociated at high pHs buffers. Maximum amounts of hemoglobin bound to 1 mg envelope was 51.2 μg. Kd for the reaction at pH 5.0 was 2.1 × 10^-10M (210 pM). From the dot blot assay, hemoglobin could bind to a protein solubilized from the envelope by a detergent, referred to as hemoglobin-binding protein (HbBP), then it was purified by the sequential procedures of ion exchange chromatography, affinity chromatography and isoelectric focusing. Molecular weight and isoelectric point of the HbBP were 46 kDa and 6.1, respectively.

[Underlying examination in the imaging of 89Sr bremsstrahlung radiation]

The radiopharmaceutical strontium chloride ((89)Sr) has been released as a new means of pain relief for painful bone metastasis in cancer patients. Because (89)Sr is a pure beta-emitting nuclide, it was considered difficult to know its distribution in the body from outside. Imaging with a gamma camera using bremsstrahlung radiation has been reported as one method, but there has been little detailed basic examination. We examined the optimal energy window and collimator when imaging with a gamma camera using bremsstrahlung radiation produced from (89)Sr beta rays. The results showed that setting the energy window at 75 keV, which is the peak formed by the characteristic X-ray of lead that is produced by the interaction of bremsstrahlung radiation and lead, is optimal for imaging. Also important are the material of the collimator and the use of an MELP collimator.

Porphyromonas gingivalis mutant defective in a putative extracytoplasmic function sigma factor shows a mutator phenotype

INTRODUCTION

Porphyromonas gingivalis is implicated as a major pathogen in the development and progression of chronic periodontitis. P. gingivalis must possess the ability to tolerate stress signals outside the cytoplasmic membrane by transcriptional activation of genes encoding proteins involved in defense or repair processes. Some bacteria utilize a distinct subfamily of sigma factors to regulate extracytoplasmic function (hence termed the ECF subfamily).

METHODS

To elucidate their role in P. gingivalis, a chromosomal mutant carrying a disruption of an ECF sigma factor PG1318-encoding gene was constructed. Hemagglutination and proteolytic activities were measured in the PG1318-defective mutant. Reverse transcription-polymerase chain reaction (RT-PCR) analysis and southern blot analysis were used to assess transcription of kgp in the PG1318-defective mutant. Frequency of spontaneous mutation that conferred resistance to l-trifluoromethionine was measured in the PG1318-defective mutant.

RESULTS

The PG1318-defective mutant formed non-pigmented colonies on blood agar plates at a relatively high frequency. Arginine-specific and lysine-specific proteinase activities of the non-pigmented variants were remarkably decreased compared with those of the parent strain and the pigmented variants. RT-PCR analysis showed that kgp was not transcribed in some non-pigmented variants and southern blot analysis revealed that there was a deletion in their kgp region. Frequency of mutation conferring resistance to l-trifluoromethionine was significantly higher in the PG1318-defective mutant than in the wild-type.

CONCLUSION

These results suggest that PG1318 plays a role in the regulation of mutation frequency in the bacterium.

Distribution in skin of ceramide after oral administration to rats

In this study, the absorption, distribution and excretion of ceramide were examined in rats. After a single oral administration of (3)H-ceramide, mean plasma concentration of radioactivity reached maximum at approximately 10.67 hr and decreased with a T(1/2) of 67.12 hr. The mean cumulative excretion of radioactivity in urine and feces accounted for approximately 4.79% and 87.44%, respectively, of the dose. At 96 hr after dosing, 1.67% and 3.67%, respectively, of the dose were still present in the skin and carcass. The radioactivity in the skin at 12 hr was lower than that in plasma and the ratio of skin to plasma concentration was 0.7. However, at 120 hr after dosing, the ratio of skin to plasma concentration increased to 4. A detailed analysis of the distribution of radioactivity in a section of skin showed that radioactivity was located in the dermis and epidermis. At 168 hr, the radioactivity in the epidermis was 8.0% of the radioactivity in skin. The results of the present study clearly demonstrate that some ceramide orally administered is distributed gradually in the dermis after gastrointestinal absorption, followed by transfer from the dermis to the epidermis.

Inorganic polyphosphate: a possible stimulant of bone formation

Inorganic polyphosphates [Poly(P)] are often distributed in osteoblasts. We undertook the present study to verify the hypothesis that Poly(P) stimulates osteoblasts and facilitates bone formation. The osteoblast-like cell line MC 3T3-E1 was cultured with Poly(P), and gene expression and potential mineralization were evaluated by reverse-transcription polymerase chain-reaction. Alkaline phosphatase activity, von Kossa staining, and resorption pit formation analyses were also determined. The potential role of Poly(P) in bone formation was assessed in a rat alveolar bone regeneration model. Poly(P) induced osteopontin, osteocalcin, collagen 1alpha, and osteoprotegerin expression and increased alkaline phosphatase activity in MC 3T3-E1 cells. Dentin slice pit formation decreased with mouse osteoblast and bone marrow macrophage co-cultivation in the presence of Poly(P). Promotion of alveolar bone regeneration was observed locally in Poly(P)-treated rats. These findings suggest that Poly(P) plays a role in osteoblastic differentiation, activation, and bone mineralization. Thus, local poly(P) delivery may have a therapeutic benefit in periodontal disease.

Molecular basis of neonatal diabetes in Japanese patients

CONTEXT

Neonatal diabetes mellitus (NDM) is classified clinically into a transient form (TNDM), in which insulin secretion recovers within several months, and a permanent form (PNDM), requiring lifelong medication. However, these conditions are genetically heterogeneous.

OBJECTIVE

Our objective was to evaluate the contribution of the responsible gene and delineate their clinical characteristics.

PATIENTS AND METHODS

The chromosome 6q24 abnormality and KCNJ11 and ABCC8 mutations were analyzed in 31 Japanese patients (16 with TNDM and 15 with PNDM). Moreover, FOXP3 and IPF1 mutations were analyzed in a patient with immune dysregulation, polyendocrinopathy, enteropathy X-linked syndrome and with pancreatic agenesis, respectively.

RESULTS

A molecular basis for NDM was found in 23 patients: 6q24 in eleven, KCNJ11 in nine, ABCC8 in two, and FOXP3 in one. All the patients with the 6q24 abnormality and two patients with the KCNJ11 mutation proved to be TNDM. Five mutations were novel: two (p.A174G and p.R50G) [corrected] in KCNJ11, two (p.A90V and p.N1122D) in ABCC8, and one (p.P367L) in FOXP3. Comparing the 6q24 abnormality and KCNJ11 mutation, there were some significant clinical differences: the earlier onset of diabetes, the lower frequency of diabetic ketoacidosis at onset, and the higher proportion of the patients with macroglossia at initial presentation in the patients with 6q24 abnormality. In contrast, two patients with the KCNJ11 mutations manifested epilepsy and developmental delay.

CONCLUSIONS

Both the 6q24 abnormality and KCNJ11 mutation are major causes of NDM in Japanese patients. Clinical differences between them could provide important insight into the decision of which gene to analyze in affected patients first.

Dipeptidyl peptidase IV of Streptococcus anginosus: purification and characterization

We found that N-unblocked nine p-nitroanilde derivatives of amino acids or peptides were hydrolyzed by the crude cell extracts of Streptococcus anginosus NCTC 10713. Then dipeptidyl peptidase IV was purified 323-fold by the procedures including ammonium sulfate concentration, anion exchange chromatography (twice), gel filtration (twice), hydrophobic interaction chromatography, and isoelectric focusing. The molecular weight was calculated as 84 kDa, and the isoelectric point was 4.9. The enzyme hydrolyzed mainly dipeptides containing proline residues at P1 position. It was strongly inhibited by serine enzyme inhibitors. General protease inhibitors, metal chelators, thiol alkylating agent, reducing agent, and several metal ions had no effect on the enzyme activity. Optimum pH for the activity was found at 7.0. The enzyme was mostly inactivated by heating at 50 degrees C for 15 min.

INVOLVEMENT OF MOLYBDENUM HYDROXYLASES IN REDUCTIVE METABOLISM OF NITRO POLYCYCLIC AROMATIC HYDROCARBONS IN MAMMALIAN SKIN

Molybdenum hydroxylases, aldehyde oxidase and xanthine oxidoreductase, were shown to be involved in the nitroreduction of 2-nitrofluorene (NF), 1-nitropyrene, and 4-nitrobiphenyl, environmental pollutants, in the skin of various mammalian species. NF was reduced to 2-aminofluorene by hamster skin cytosol in the presence of 2-hydroxypyrimidine, 4-hydroxypyrimidine, N(1)-methylnicotinamide, or benzaldehyde, but not hypoxanthine or xanthine. Inhibitors of aldehyde oxidase markedly inhibited these nitroreductase activities, but oxypurinol, an inhibitor of xanthine oxidoreductase, had little effect. In DEAE column chromatography of hamster skin cytosol, the major fraction exhibiting nitroreductase activity also showed aldehyde oxidase activity. 2-Hydroxypyrimidine-linked nitroreductase activities of skin cytosol from rabbits and guinea pigs were also inhibited by an inhibitor of aldehyde oxidase. In contrast, nitroreductase activities of skin cytosols of rats and mice were markedly inhibited by oxypurinol. When aldehyde oxidase activity was estimated in skin cytosol of various mammals using benzaldehyde oxidase activity as a marker, considerable variability of the activity was found. The highest activity was observed with hamsters, and the lowest activity with rats. On the other hand, the highest xanthine oxidoreductase activity was observed with rats, and the lowest activity with rabbits. These skin cytosols of various mammals also exhibited significant 2-hydroxypyrimidine-linked nitroreductase activities toward 1-nitropyrene and 4-nitrobiphenyl catalyzed by aldehyde oxidase and xanthine oxidoreductase. Thus, NF was mainly reduced by aldehyde oxidase and xanthine oxidoreductase in skins of animals. However, the contributions of these two molybdenum hydroxylases were considerably different among animal species.

Mutations in human urate transporter 1 gene in presecretory reabsorption defect type of familial renal hypouricemia

To date, 11 loss of function mutations in the human urate transporter 1 (hURAT1) gene have been identified in subjects with idiopathic renal hypouricemia. In the present studies we investigated the clinical features and the mutations in the hURAT1 gene in seven families with presecretory reabsorption defect-type renal hypouricemia and in one family with the postsecretory reabsorption defect type. Twelve affected subjects and 26 family members were investigated. Mutations were analyzed by PCR and the direct sequencing method. Urate-transporting activities of wild-type and mutant hURAT1 were determined by [14C]urate uptake in Xenopus oocytes. Mutational analysis revealed three previously reported mutations (G774A, A1145T, and 1639-1643 del-GTCCT) and a novel mutation (T1253G) in families with the presecretory reabsorption defect type. Neither mutations in the coding region of hURAT1 gene nor significant segregation patterns of the hURAT1 locus were detected in the postsecretory reabsorption defect type. All hURAT1 mutants had significantly reduced urate-transporting activities compared with wild type (P < 0.05; n = 12), suggesting that T1253G is a loss of function mutation, and hURAT1 is responsible for the presecretory reabsorption defect-type familial renal hypouricemia. Future studies are needed to identify a responsible gene for the postsecretory reabsorption defect-type familial renal hypouricemia.

[A successful management of acute myocardial infarction with severe left main trunk lesion using beating heart coronary artery bypass grafting: report of a case]

A 56-year-old male was admitted for sudden onset of severe chest pain and diagnosed as acute myocardial infarction (AMI). Emergency coronary angiography revealed complete obstruction of the left anterior descending artery (LAD) and 99% stenosis of left circumflex coronary artery (LCX), which was almost same with obstruction of the left main trunk coronary artery. Emergency coronary artery bypass grafting (CABG) to LAD and LCX was performed under a beating-heart. Left ventricular wall motion was improved after bypass grafting. CABG under a beating-heart is a new strategy for critical cases such as acute coronary syndrome. The better patency rate and the more complete revascularization that may be achieved with the new generation of stabilizers and retractors may improve long-term results.

A successful management of concomitant renovascular hypertension and symptomatic subclavian steal syndrome due to Takayasu's arteritis using balloon angioplasty and axillo-axillary bypass grafting

We present a case of Takayasu's arteritis with severe renovascular hypertension and symptomatic subclavian steal syndrome. A 60-year-old woman underwent successful percutaneous balloon renal angioplasty and axillo-axillary bypass grafting. The role of hybrid therapy, angioplasty and extra-anatomical bypass grafting for revascularization of symptomatic ischemia in this disease is reviewed. (Ann Thorac Cardiovasc Surg 2003: 9; 334-6)

Comparison of ability of apoptosis induction by lipopolysaccharide of Porphyromonas gingivalis with Escherichia coli

We compared effects of Porphyromonas gingivalis LPS with Escherichia coli LPS to the murine peritoneal macrophage. E. coli LPS possessed a threshold dose between 100 micro g and 10 micro g, the higher dose induced apoptosis at the murine peritoneal macrophage while the lower dose did not. The ability of apoptosis induction at the murine peritoneal macrophage of P. gingivalis LPS was weaker than E. coli LPS. P. gingivalis LPS did not induce significant apoptosis in all tested dose. However, the morphology of the peritoneal macrophage treated by P. gingivalis LPS was obviously different from that of the unstimulated cells.

Acute mitral regurgitation due to total rupture in the anterior papillary muscle after acute myocardial infarction successfully treated by emergency surgery

A 68-year-old female was admitted for sudden onset of chest pain. She received a successful percutaneus coronary intervension for total occlusion in the diagonal artery, but continued to develop progressive heart failure. A chest X-ray showed right pulmonary edema without cardiomegaly, and an echocardiogram revealed massive mitral regurgitation with prolapse in the anterior mitral leaflet due to a rupture in the papillary muscle. An emergency operation was conducted using routine cardiopulmonary bypass. There was complete rupture in the anterior papillary muscle. Mitral valve replacement with posterior mitral leaflet preservation was performed using a size 25 mm Carbomedics prosthetic valve. The postoperative course was uneventful, and she was discharged on postoperative day 29 in New York Heart Association class I. Postoperative pathological findings showed necrosis in the papillary muscle with inflammatory changes. Early diagnosis, prompt medical stabilization, and aggressive surgical intervention are essential to save such a group of patient.

Xanthine oxidase-catalyzed metabolism of 2-nitrofluorene, a carcinogenic air pollutant, in rat skin

The reductive metabolism of 2-nitrofluorene, a carcinogenic air pollutant, in rat skin microsomes and cytosol was investigated. 2-Nitrofluorene was reduced to the corresponding amine by the microsomes with NADPH and by the cytosol with 2-hydroxypyrimidine or 4-hydroxypyrimidine under anaerobic conditions. The cytosolic activity was much higher than that of skin microsomes. The 2- or 4-hydroxypyrimidine-linked nitroreductase activity was inhibited by oxypurinol and (+/-)-8-(3-methoxy-4-phenylsulfinylphenyl) pyrazolo[1,5-a]-1,3,5-triazine-4(1H)-one (BOF-4272), inhibitors of xanthine oxidase, but not by menadione, chlorpromazine and isovanillin, inhibitors of aldehyde oxidase. When skin cytosol was applied to a DEAE-cellulose column, the fractions containing xanthine oxidase exhibited a marked 2-hydroxypyrimidine-linked nitroreductase activity. In contrast, the aldehyde oxidase fraction showed little activity. Nitroreductase fractions obtained by ion exchange chromatography showed a band in Western blotting analysis using anti-rat xanthine oxidase. Moreover, the xanthine oxidase fraction exhibited a significant nitroreductase activity in the presence of 2-hydroxypyrimidine, 4-hydroxypyrimidine or hypoxanthine, and these activities were inhibited by inhibitors of xanthine oxidase. These results indicated that reduction of 2-nitrofluorene in the skin was mainly catalyzed by xanthine oxidase.

Metabolism of 2-nitrofluorene, an environmental pollutant, by liver preparations of sea bream, Pagrus major

1. The in vitro metabolism of 2-nitrofluorene (NF), an environmental pollutant, was examined in fish, focusing on nitro-reduction followed by N-acylation and hydroxylation. 2. When NF was incubated with liver microsomes or cytosol of sea bream, Pagrus major, in the presence of NADPH or 2-hydroxypyrimidine, 2-aminofluorene (AF) was formed. 3. When AF was incubated with liver cytosol in the presence of acetyl-CoA or N-formyl-L-kynurenine, 2-acetylaminofluorene (AAF) or 2-formylaminofluorene (FAF) was formed, respectively. AAF and FAF thus formed were deacylated to the parent AF by the liver preparations. 4. AF, AAF and FAF were oxidized to 7-hydroxy or 5-hydroxy derivatives by the liver microsomes. 5. Nitro-reduction, N-acylation and ring-hydroxylation of NF and the metabolites were also observed in rat liver preparations. These activities in sea bream livers were lower than those of rat liver. However, the order of magnitude of these activities in fish was the same as in rat. 6. It is suggested that NF is effectively reduced to AF by the cytochrome P450 system or aldehyde oxidase, and the acylated metabolites, AAF and FAF, generated by arylamine acetyltransferase and formamidase were hydroxylated by the cytochrome P450 system in fish in the same way as in rat. Further, the acetylamino and formylamino derivatives were interconverted via amino derivatives in the fish.

Deacylation of N-arylformamides and N-arylacetamides by formamidase in rat liver

The in vitro deacylation of N-arylformamides and N-arylacetamides to arylamines was examined in rat liver preparations. When 2-acetylaminofluorene or 2-formylaminofluorene was incubated with rat liver microsomes or cytosol, the deacylated metabolite, 2-aminofluorene, was formed. The deacylating activity of liver microsomes was inhibited by bis(4-nitrophenyl)phosphate and phenylmethanesulfonyl fluoride, inhibitors of carboxylesterase. In contrast, the activity of liver cytosol was inhibited by diisopropyl fluorophosphate, an inhibitor of formamidase. Deacylation of these compounds appear to be mainly catalyzed by carboxylesterase in liver microsomes and formamidase in liver cytosol. 2-Formylaminofluorene, 2-acetylaminofluorene, 1-formylaminopyrene, 4-formylaminobiphenyl, 2-formylaminonaphthalene, 1-formylaminonaphthalene, and 2-acetylaminofluorene were deacylated by formamidase purified from rat liver cytosol. Formamidase catalyzed both N-formylation of arylamines, and deacylation of N-arylformamides and N-arylacetamides.

Renal damage and salt-dependent hypertension in aged transgenic mice overexpressing endothelin-1

The recent development of endothelin-1 (ET-1) antagonists and their potential use in the treatment of human disease raises questions as to the role of ET-1 in the pathophysiology of such cardiovascular ailments as hypertension, heart failure, renal failure and atherosclerosis. It is still unclear, for example, whether activation of an endogenous ET-1 system is itself the primary cause of any of these ailments. In that context, the phenotypic manifestations of chronic ET-1 overproduction may provide clues about the tissues and systems affected by ET-1. We therefore established two lines of transgenic mice overexpressing the ET-1 gene under the direction of its own promoter. These mice exhibited low body weight, diminished fur density and two- to fourfold increases in the ET-1 levels measured in plasma, heart, kidney and aorta. There were no apparent histological abnormalities in the visceral organs of young (8 weeks old) transgenic mice, nor was their blood pressure elevated. In aged (12 months old) transgenic mice, however, renal manifestations, including prominent interstitial fibrosis, renal cysts, glomerulosclerosis and narrowing of arterioles, were detected. These pathological changes were accompanied by decreased creatinine clearance, elevated urinary protein excretion and salt-dependent hypertension. It thus appears that mild, chronic overproduction of ET-1 does not primarily cause hypertension but triggers damaging changes in the kidney which lead to the susceptibility to salt-induced hypertension.

A MATE family multidrug efflux transporter pumps out fluoroquinolones in Bacteroides thetaiotaomicron

We cloned a gene, bexA, that codes for a multidrug efflux transporter from the chromosomal DNA of Bacteroides thetaiotaomicron ATCC 29741 by using an Escherichia coli DeltaacrAB DeltaacrEF mutant as a host. Although the initial recombinant construct contained other open reading frames, the presence of bexA alone was sufficient to confer to the E. coli host elevated levels of resistance to norfloxacin, ciprofloxacin, and ethidium bromide. Disruption of bexA in B. thetaiotaomicron made the strain more susceptible to norfloxacin, ciprofloxacin, and ethidium bromide, showing that this gene is expressed in this organism and functions as a multidrug efflux pump. The deduced BexA protein sequence was homologous to the protein sequence of Vibrio parahaemolyticus NorM, a multidrug efflux transporter, and thus, BexA belongs to the multidrug and toxic compound extrusion (MATE) family.

Application of the piezo-micromanipulator for injection of embryonic stem cells into mouse blastocysts

Microinjection of embryonic stem (ES) cells into mouse blastocysts is one of the most important techniques for production of knockout or transgenic mice. However, skillful manipulation techniques and tremendous effort are required for this method. To overcome this difficulty, we applied a piezo-micromanipulator (PMM), which has been used for intracytoplasmic sperm injection in mice and production of cloned mice, for the injection of ES cells into blastocysts. When ES cells were injected by using a conventional method, 91% of the blastocysts were manipulated successfully. Using the PMM significantly (P < 0.01) increased the success rate of ES injection to 97%. The number of embryos manipulated in an hour increased from 9.7 embryos with the conventional method to 27.0 embryos with the PMM method. The injected ES cells did not show any detrimental effects due to a pulse from the PMM. After embryo transfer of the manipulated blastocysts, 39% of the newborns were chimeric mice with the conventional method, whereas 42% of the neonates were chimeric after the PMM method. These results indicate that microinjection of the ES cells into blastocysts is more efficient by the PMM method than the conventional method.

Alpha-tocopherol transfer protein is important for the normal development of placental labyrinthine trophoblasts in mice

Alpha-tocopherol transfer protein (alpha-TTP), a cytosolic protein that specifically binds alpha-tocopherol, is known as a product of the causative gene in patients with ataxia that is associated with vitamin E deficiency. Targeted disruption of the alpha-TTP gene revealed that alpha-tocopherol concentration in the circulation was regulated by alpha-TTP expression levels. Male alpha-TTP(-/-) mice were fertile; however, placentas of pregnant alpha-TTP(-/-) females were severely impaired with marked reduction of labyrinthine trophoblasts, and the embryos died at mid-gestation even when fertilized eggs of alpha-TTP(+/+) mice were transferred into alpha-TTP(-/-) recipients. The use of excess alpha-tocopherol or a synthetic antioxidant (BO-653) dietary supplement by alpha-TTP(-/-) females prevented placental failure and allowed full-term pregnancies. In alpha-TTP(+/+) animals, alpha-TTP gene expression was observed in the uterus, and its level transiently increased after implantation (4.5 days postcoitum). Our results suggest that oxidative stress in the labyrinth region of the placenta is protected by vitamin E during development and that in addition to the hepatic alpha-TTP, which governs plasma alpha-tocopherol level, the uterine alpha-TTP may also play an important role in supplying this vitamin.

Metabolism of 2-nitrofluorene, 2-aminofluorene and 2-acylaminofluorenes in rat and dog and the role of intestinal bacteria

1. The in vivo metabolism of 2-nitrofluorene (NF), an environmental pollutant, and 2-aminofluorene (AF) and its acylated derivatives, 2-formylaminofluorene (FAF) and 2-acetylaminofluorene (AAF), was examined in rat and dog. 2. 7-Hydroxy-2-nitrofluorene, 5-hydroxy-2-nitrofluorene, AF, AAF, FAF, 7-hydroxy-2-aminofluorene, 5-hydroxy-2-aminofluorene, 7-hydroxy-2-acetylaminofluorene, 5-hydroxy-2-acetylaminofluorene, 7-hydroxy-2-formylaminofluorene and 5-hydroxy-2-formylaminofluorene were identified as urinary and faecal metabolites of NF in rat and dog. 3. AAF and its hydroxylated derivatives were detected as major metabolites of NF in rat, but FAF and its hydroxylated metabolites were mainly excreted in dog. 4. AF, AAF, FAF and their hydroxylated metabolites were also identified as urinary and faecal metabolites of AF, AAF or FAF in rat, suggesting that AAF and FAF are interconverted via AF. 5. Treatment of rat and dog with antibiotics significantly decreased the urinary and faecal excretion of AF and its derivatives after oral administration of NF, and partly decreased the excretion of acylated metabolites after an oral dose of AF. 6. The caecal contents of untreated rats and some species of intestinal bacteria exhibited nitro-reductase activity toward NF, and acylating activity toward AF, affording AAF and FAF.