Degradation of 1,3-dichloropropene by a soil bacterial consortium and Rhodococcus sp. AS2C isolated from the consortium

A bacterial consortium capable of degrading the fumigant 1,3-D ((Z)- and (E)- 1,3-dichloropropene) was enriched from an enhanced soil. This mixed culture degraded (Z)- and (E)-1,3-D only in the presence of a suitable biodegradable organic substrate, such as tryptone, tryptophan, or alanine. After 8 months of subculturing at 2- to 3-week intervals, a strain of Rhodococcus sp. (AS2C) that was capable of degrading 1,3-D cometabolically in the presence of a suitable second substrate was isolated. (Z)-3-chloroallyl alcohol (3-CAA) and (Z)-3-chloroacrylic acid (3-CAAC), and (E)-3-CAA and (E)-3-CAAC were the metabolites of (Z)- and (E)- 1,3-D, respectively. (E)- 1,3-D was degraded faster than (Z)- 1,3-D by the strain AS2C and the consortium. AS2C also degraded (E)-3-CAA faster than (Z)-3-CAA. Isomerization of (E)- 1,3-D to (Z)- 1,3-D or the (Z) form to the (E) form did not occur.

Flux enhancement with gas injection in crossflow ultrafiltration of oily wastewater

The gas injection technique was introduced to achieve flux improvement in cross-flow ultrafiltration of oil emulsion. By the nitrogen gas injection, homogeneous liquid phase oil/water emulsion was changed to heterogeneous gas- liquid phase. The injected gas causes positive effect of promoting turbulence, but it also has negative effect of decreasing the effective membrane area due to the partial occupation of membrane pores by bubbles. The efficiency of the gas injection was found out to be dependent on bubble fractions in the mixture: at sufficient bubble fractions the higher flux was observed. but at lower bubble fractions the flux rather decreased compared with that without gas injection. An attempt was made to explain the mechanisms for the dual aspects of gas injection. Turbulence dampening effect was also observed when the dependence of mass transfer coefficient on cross-flow rate was investigated with gas injection.

Formation of DNA triple helix containing N(4)-(6-aminopyridin-2-yl)-2'-deoxycytidine

A cytidinyl derivative, N(4)-(6-aminopyridin-2-yl)- 2'-deoxycytidine ((p)C), could interact with a CG base pair to support the triple-helix (triplex) formation of oligodeoxyribonucleotides. Characteristics of (p)C in the formation of both intramolecular triplex, i.e., a "paper clip type" triplex ((P)CT) and intermolecular triplex, i.e., a "linear type" triplex (LT) was monitored by optical methods and isothermal titration calorimetric measurements. Experimental results revealed that the LT with (p)C*CG internally was independent of the solution pH. Only single substitution of (p)C, situated internally but not terminally, facilitated the (P)CT formation by the UV thermal melting study at the neutral pH. However, the best stabilization of the PCT in acidic conditions occurred when (p)C at the end of the triplex rather than internally. In addition, an LT, but not a (P)CT, containing an alternating (p)CT(p)CT(p)C sequence, could be formed in the conditions of 20 mM MgCl(2) and/or 5 mM spermine. Thus, the presence of several nucleotides of (p)C in proximity along the Hoogsteen strand may lead to structural distortion such that the more flexible LT with multiple substitutions is formed in favor of the more rigid PCT.

Thymoma with pseudosarcomatous stroma

Thymoma with psuedosarcomatous stroma is a recently described, rare variant of thymomas that are characterized by having a biphasic histologic pattern which consists of both an epithelial and a spindle cell stromal component. So far only 11 cases having similar histologic findings have been reported worldwide. At this time we report a case of this rare variant of thymoma which occurred in a 53-year-old Korean man. This previously healthy patient presented with coughing and an anterior mediastinal mass was then detected radiographically. Mediastinal exploration revealed a 9 x 8 x 8 cm-sized well- encapsulated, ovoid, cystic mass. Histological examination showed a biphasic neoplasm composed of anastomosing nests of epithelial cells and somewhat cellular stromal spindle cells that had advanced degenerative changes. Immunohistochemical staining using the antibodies for cytokeratins, EMA, e-cadherin, and p75NGFR showed a strong expression of these markers in the epithelial component but no expression in the spindle stromal cells. The epithelial tumor cells showed no reactivity to CD5 and L26 and a high proportion of the infiltrated lymphocytes were the cortical type that expressed CD99 and terminal deoxynucleotidyl transferase. Ultrastructural examinations revealed tonofilaments in the spindle cells. Follow up has been done for 5 years after the surgical excision and the patient has been free of disease during that period. Similar to previous reports, this patient had a benign clinical course that was unassociated with myasthenia gravis which appears to be a characteristic of this histologic variant of thymoma. However, our case also showed advanced degenerative features and we could demonstrate ultrastructural evidence of epithelial differentiation in the stromal spindle cells that were not mentioned in the previously reported cases. Based on the results of our studies, we suggest this entity is a distinct type of organotypic thymoma that shows cortical differentiation and abundant cellular stroma.

Heparan sulfate proteoglycan expression in the optic chiasm of mouse embryos

Previous studies have demonstrated that heparan sulfate (HS) proteoglycans (PGs) regulate neurite outgrowth through binding to a variety of cell surface molecules, extracellular matrix proteins, and growth factors. The present study investigated the possible involvement of HS-PGs in retinal axon growth by examining its expression in the retinofugal pathway of mouse embryos by using a monoclonal antibody against the HS epitope. Immunoreactive HS was first detected in all regions of the retina at embryonic day (E) 11. The staining was gradually lost in the central regions and restricted to the retinal periphery at later developmental stages (E12--E16). Prominent staining for HS was consistently found in the retinal fiber layer and at the optic disk, indicating a possible supportive role of HS-PGs in axon growth in the retina. At the ventral diencephalon, immunostaining for HS was first detected at E12, before arrival of any retinal axons. The staining matched closely the neurons that are immunopositive for the stage-specific embryonic antigen 1 (SSEA-1). At E13 to E16, when axons are actively exploring their paths across the chiasm, immunoreactivity for HS was particularly intense at the midline. This characteristic expression pattern suggests a role for HS-PGs in defining the path of early axons in the chiasm and in regulating development of axon divergence at the midline. Furthermore, HS immunoreactivity is substantially reduced at regions flanking both sides of the midline, which coincides spatially to the position of actin-rich growth cones from subpial surface to the deep regions of the optic axon layer at the chiasm. Moreover, at the threshold of the optic tract, immunoreactive HS was localized to deep parts of the fiber layer. These findings indicate that changes in age-related fiber order in the optic chiasm and optic tract of mouse embryos are possibly regulated by a spatially restricted expression of HS-PGs.

Cardiac arrhythmias in F-16 pilots during aerial combat maneuvers (ACMS): a descriptive study focused on G-level acceleration

INTRODUCTION

It is well known that acceleration during centrifuge training provokes cardiac arrhythmias. However, there is little research regarding cardiac arrhythmia during actual flight. Therefore, to identify the kinds of cardiac arrhythmias that occur in response to the Aerial Combat Maneuvers (ACM) environment, we analyzed electrocardiograms (ECG) of 35 male pilots.

METHODS

ECGs were recorded from 35 pilots (mean age 31 yr, range 27-39) from 1 h before take-off to 1 h after landing. G-load was simultaneously recorded. To see the patterns of the arrhythmia as Gz force increased, ECG data of each subject were classified into three G levels: a) G-level A was < +3 G; b) G-level B was > or = +3 G but < +6 G lasting longer than 3 s; and c) G-level C was > or = +6 G lasting longer than 3 s.

RESULTS

Mean total flying time of the 35 pilots was 1475 h (range 578-3300). Arrhythmias were observed in 17 of the pilots (49%) during ECG recording. Four pilots (11.4%) experienced arrhythmias before take-off, 16 pilots (45.7%) inflight and 4 pilots (11.4%) after landing. Arrhythmias were recorded in 13 of 35 pilots (37.1%) at G-level A, in 10 of 35 pilots (28.6%) at G-level B and in 1 of 21 pilots (5%) at G-level C. During flight, unifocal premature ventricular contractions (PVC) were experienced by three of the subjects (8.6%); supraventricular premature beats (SVPB) by four subjects (11.4%), and PVCs with bigeminy by one subject (2.9%). Eight subjects (22.9%) experienced combined arrhythmias.

CONCLUSION

There were no clinically significant arrhythmias recorded during ACM in these experienced pilots.

C-H and C-C bond activation of primary amines through dehydrogenation and transimination

[structure: see text]. Dehydrogenation and subsequent transimination of primary amines offer a new pathway for C-H bond activation, ortho-alkylation, and C-C bond activation to afford a variety of ketones in the reaction of 1-alkene by a cocatalyt system of Rh(I) and 2-amino-3-picoline.

C-H and C-C bond activation of primary amines through dehydrogenation and transimination

[structure: see text]. Dehydrogenation and subsequent transimination of primary amines offer a new pathway for C-H bond activation, ortho-alkylation, and C-C bond activation to afford a variety of ketones in the reaction of 1-alkene by a cocatalyt system of Rh(I) and 2-amino-3-picoline.

Three cases of fistulae arising from gastrointestinal tract treated with endoscopic injection of Histoacryl

Treatment of gastrointestinal fistula usually consists of conservative management and surgery as definite therapeutic measure. Histoacryl can be used to treat gastrointestinal fistula with no response to conservative management in surgically high-risk patients. We report here three cases of gastrointestinal fistula successfully treated with endoscopic injection of Histoacryl through a catheter into the internal opening and fistulous tract.

A study on dust emission, particle size distribution and formaldehyde concentration during machining of medium density fibreboard

A study to characterise the quantity, particle size distribution and morphology of dust created during the machining of MDF was carried out. Four different types of MDF boards were included in this study, including a 'zero-formaldehyde' board that contains isocyanate-based resin, rather than urea-formaldehyde resin. In addition, natural softwood (pine) and natural hardwood (oak) were included in the study, for comparison with MDF. The results show that in general, the dust generated by machining MDF is comparable in terms of particle size distribution and morphology with the dust generated by similarly machining hardwood or softwood. The quantity of dust generated during sanding is higher for sanding MDF compared with sanding either hardwood or softwood. However, for sawing there is no significant difference between MDF and natural woods, in terms of the quantity of dust generated. Free formaldehyde in the air was less than 0.17mg m(-3) during machining of the Class B (higher formaldehyde potential) MDF board. There was no measurable isocyanate in the dust generated from the boards.

Inhibitory effect of sodium salicylate on nitric oxide production from TM4 sertoli cells

Nitric oxide (NO) has been proposed to play a role in a variety of inflammatory diseases. Sodium salicylate (NaSal) is the most commonly used anti-inflammatory agent. We investigated whether NaSal can diminish the production of NO in TM4 Sertoli cells. TM4 Sertoli cells produced a small amount of NO upon treatment with recombinant interferon-gamma (rIFN-gamma). The effect of rIFN-gamma was enhanced markedly by the addition of recombinant TNF-alpha (rTNF-alpha) in a dose-dependent manner. NaSal (10 and 20 mM) significantly inhibited NO production from TM4 Sertoli cells induced by rIFN-gamma plus rTNF-alpha. In addition, rIFN-gamma in combination with rTNF-alpha showed a marked increase of the expression of inducible NO synthase (iNOS) protein. Western blot analysis revealed that NaSal (10 and 20 mM) blocked a step of iNOS protein synthesis. The rIFN-gamma plus rTNF-alpha-induced nuclear factor-kappaB (NF-kappaB) activation was significantly blocked by NaSal (10 and 20 mM). On the other hand, neither staurosporine nor polymyxin B significantly inhibited NO production from TM4 Sertoli cells induced by rIFN-gamma plus rTNF-alpha. The present results indicate that NaSal inhibits rIFN-gamma plus rTNF-alpha-induced NO production in TM4 Sertoli cells via the signal transduction pathway of NF-kappaB activation.

Axon routing at the optic chiasm after enzymatic removal of chondroitin sulfate in mouse embryos

The effects of removing chondroitin sulfate from chondroitin sulfate proteoglycan molecules on guidance of retinal ganglion cell axons at the optic chiasm were investigated in a brain slice preparation of mouse embryos of embryonic day 13 to 15. Slices were grown for 5 hours and growth of dye-labeled axons was traced through the chiasm. After continuous enzymatic digestion of the chondroitin sulfate proteoglycans with chondroitinase ABC, which removes the glycosaminoglycan chains, navigation of retinal axons was disrupted. At embryonic day 13, before the uncrossed projection forms in normal development, many axons deviated from their normal course, crossing the midline at aberrant positions and invading the ventral diencephalon. In slices from embryonic day 14 embryos, axons that would normally form the uncrossed projection at this stage failed to turn into the ipsilateral optic tract. In embryonic day 15 slices, enzyme treatment caused a reduction of the uncrossed projection that develops at this stage. Growth cones in enzyme-treated slices showed a significant increase in the size both before and after they crossed the midline. This indicates that responses of retinal axons to guidance signals at the chiasm have changed after removal of the chondroitin sulfate epitope. We concluded that the chondroitin sulfate moieties of the proteoglycans are involved in patterning the early phase of axonal growth across the midline and at a later stage controlling the axon divergence at the chiasm.

Expression of chondroitin sulfate proteoglycans in the chiasm of mouse embryos

Chondroitin sulfate (CS) proteoglycans have been implicated as molecules that are involved in axon guidance in the developing neural pathways. The spatiotemporal expression of CS was investigated in the developing retinofugal pathway in mouse embryos by using the CS-56 antibody. Immunoreactive CS was detected in inner regions of the retina as early as embryonic day 11 (E11). Its expression in subsequent stages of development followed a centrifugal, receding gradient that appeared to correlate with the sequence of axogenesis in the retina. In the chiasm, immunoreactive CS was expressed at E12, before the arrival of retinal axons. When the retinal axons navigated in the chiasm at E13-E14, immunoreactive CS remained at a low level in the optic fiber layer of the chiasm but was observed prominently in the caudal parts of the ventral diencephalon. This pattern followed closely the array of stage-specific-embryonic-antigen-1-positive neurons in the ventral diencephalon, with a V-shaped configuration that bordered the posterior boundary of the retinal axons, and a rostral raphe extension that ran across the decussating axons in the chiasm. Thus, the CS epitope is implicated in patterning the course of early retinal axons and in regulating axon divergence in the chiasm. At the lateral region of the chiasm, where the retinal axons cross the midline and approach the optic tract, a CS-immunopositive region coincided with the region in which active sorting of dorsal retinal axons from ventral retinal axons occurs. Moreover, at the threshold of the optic tract, the immunoreactive CS was restricted only to the deep part of the optic fiber layer, suggesting an inhibitory role of the CS epitope in repelling newly arrived axons to superficial regions of the optic tract during the development of chronotopic order at this part of the retinofugal pathway.

Reaction monitoring of succinylation of collagen with matrix-assisted laser desorption/ionization mass spectrometry

Succinylated collagen was synthesized by the reaction of collagen with succinic anhydride under basic conditions for one hour. Using the matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) technique, the reaction products were directly identified without multi-step separation processes. MALDI-MS monitored the reaction more accurately than the conventional method of sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). From the change in molecular mass during the reaction, it is observed that about 28 succinyl groups are attached to the collagen strand.

Common blue naevus with satellite lesions: possible perivascular dissemination resulting in a clinical resemblance to malignant melanoma

We report a case of common blue naevus with polymorphous guttate and linear satellite lesions, thereby mimicking peripherally spreading malignant melanoma. Histopathologic examination showed that the naevus cells are clustered around blood vessels in the primary as well as satellite lesions, suggestive of spreading of the naevus cells along the perivascular space. Such biological behaviour resulting in a clinical manifestation of a malignant melanoma-like lesion is a rarity in common blue naevus, a benign cutaneous disorder that is devoid of a malignant potential, and has not been described before.

Regulation of type I collagen and interstitial collagenase mRNA expression in human dermal fibroblasts by colchicine and D-penicillamine

Sclerosis is a disease process in which idiopathic hardening occurs in the skin and/or internal organs as a result of the accumulation of type I collagen, induced mainly by transforming growth factor-beta. Colchicine and D-penicillamine are widely used for its treatment. Their effects are known to be due to post-translational down-regulation of type I collagen synthesis, with colchicine also up-regulating interstitial collagenase. To determine whether or not they have any pre-translational effect on type I collagen and MMP-1, and also to observe their effects on the action of TGF-beta, cultured neonatal foreskin fibroblasts were treated with colchicine and D-penicillamine, singly and together. The amount of type I collagen and MMP-1 mRNA were quantitated by Northern blot hybridization. Colchicine suppresses the basal level of type I collagen mRNA but minimally stimulates the mRNA expression of MMP-1, whereas D-penicillamine does not have any significant effects on either. Colchicine was also able to significantly suppress the TGF-beta-induced up-regulation of type I collagen mRNA expression.

The effects of early prenatal monocular enucleation on the routing of uncrossed retinofugal axons and the cellular environment at the chiasm of mouse embryos

Whereas it has been shown that early monocular enucleations produce a reduction in the uncrossed pathway from the surviving eye in rats and ferrets, similar evidence for binocular interactions in the development of the uncrossed component in mice is currently open to question. Using retrograde tracing, we have investigated the time course of changes in the uncrossed retinofugal pathway immediately after the early prenatal monocular enucleation in mouse embryos. Removal of one eye from C57 pigmented mice at embryonic day (E) 13 does not cause a reduction of the earliest uncrossed component from the central retina examined 1 day later at E14. However, a substantial reduction of the uncrossed pathway is seen at E15, the time when the major uncrossed projection first arises from the ventral temporal retina. This reduction is greater in E16 one-eyed embryos, indicating that most retinal axons from the ventral temporal retina rely on a binocular interaction for their turning at the chiasm. Further, early removal of one eye at E13 does not produce any obvious changes in the cytoarchitecture of RC-2-immunopositive radial glia at the chiasm, nor of the stage-specific antigen-1 (SSEA-1) -expressing neurons. This lack of changes in the cellular organization at the chiasm indicates that the reduction of the uncrossed pathway is probably produced by an elimination of binocular fibre interactions at the chiasm, rather than through a degenerative change of cellular elements at the chiasm as a consequence of the eye removal procedure.

Changes in axon arrangement in the retinofugal [correction of retinofungal] pathway of mouse embryos: confocal microscopy study using single- and double-dye label

The changes in quadrant-specific fiber order in the retinofugal pathway of the C57-pigmented mouse aged embryonic day 15 were investigated by using single- (1,1'-dioctadecyl-3,3,3',3'-tetramethyl-indocarbocyanine perchlorate; DiI) and double- (N-4-4-didecylaminostyryl-N-methylpyridinium iodide; 4Di-10ASP in addition to DiI) labeling techniques. At this earliest stage of development, before any fibers arrive at their targets, retinal axons display a distinct quadrant-specific order at the optic stalk close to the eye. This order gradually disappears along the stalk and is virtually lost at the chiasm, as shown in single-label preparations. The double-label preparations, in which the population peaks of fibers from two retinal quadrants are shown simultaneously in an image, show a fiber arrangement at the chiasm that is different from the pattern seen in the single-label preparations. A distinct and consistent preferential distribution of fibers from different retinal quadrants is shown in the chiasm. Before the midline, the central part of the cross section of the chiasm is dominated by dorsal fibers, whereas the rostral and caudal parts of the chiasm are dominated by ventral nasal and ventral temporal fibers, respectively. Moreover, the double-label preparations demonstrate a major reshuffling of fiber position after the fibers cross the midline. Fibers from ventral retina are shifted gradually to a rostral position at the threshold of the optic tract, whereas fibers from dorsal retina are shifted caudally. These changes in fiber position indicate a postmidline location in the chiasm, where fibers are re-sorted in accordance with their origins in the dorsal ventral axis of the retina, and suggest a change in axon response to guidance signals when the fibers cross the midline of the chiasm. These changes in fiber order may also be related to the re-sorting of fibers according to their ages at the postmidline chiasm.

Nuclear factor-kappa B mediates TNF-alpha inhibitory effect on alpha 2(I) collagen (COL1A2) gene transcription in human dermal fibroblasts

Among its plethora of activities as an inflammatory mediator, TNF-alpha has potent regulatory control on extracellular matrix production and degradation. Earlier studies have documented that TNF-alpha inhibits type I collagen gene (COL1A2) expression at the transcriptional level, but the characterization of the transcription factors involved has been elusive. In the present study, using transient cell transfection of human dermal fibroblasts with a battery of 5' end deletion/chloramphenicol acetyltransferase (CAT) reporter gene constructs, we have characterized the TNF-alpha response element of the COL1A2 promoter. The TNF-alpha response element was attributed to a specific region that comprises noncanonical activator protein-1 (AP-1) (CGAGTCA) and NF-kappa B (AGAGTTTCCC) binding sites. TNF-alpha effect was eliminated by a 2-bp substitution mutation in the NF-kappa B1 binding half site of the NF-kappa B cis element. Electrophoretic mobility shift assays (EMSA) showed that recombinant human NF-kappa B heterodimers as well as NF-kappa B1 and RelA homodimers, but not AP-1, were capable of binding this element. Further, EMSA with human fibroblast nuclear extracts demonstrated enhanced binding of a single, specific complex within 5 min of TNF-alpha stimulation, which reached a plateau by 1 h and was not affected by preincubation of cells with cycloheximide. Gel supershift assays identified the complex as the NF-kappa B (p50/p65) heterodimer, whereas Abs to nuclear factor of activated T cells (NF-AT) and Jun family members failed to recognize the complex. These data suggest that in fibroblasts TNF-alpha activates and initiates the nuclear translocation of NF-kappa B that binds a divergent NF-kappa B element and plays a critical role in the observed inhibition of alpha 2(I) collagen gene transcription.

Erythema dyschromicum perstans in early childhood

Erythema dyschromicum perstans (EDP) is a rare disorder characterized by asymptomatic, slowly progressive, ash-gray macular pigmentation of the skin which usually occurs from age 5 through adult life. We have experienced two cases of EDP in children aged 2 and 3, both exceptionally younger than the previously reported cases. We therefore suggest that EDP should be included in the differential diagnosis of pigmentary disorders occurring at an early age.

Laboratory evaluation of a protocol for personal sampling of airborne particles in welding and allied processes

A new European/International Standard (ISOprEN 10882-1) on the sampling of airborne particulates generated during welding and allied processes has been proposed. The use of a number of samplers and sampling procedures is allowable within the defined protocol. The influence of these variables on welding fume exposures measured during welding and grinding of stainless and mild steel using the gas metal arc (GMA) and flux-cored arc (FCA) and GMA welding of aluminium has been examined. Results show that use of any of the samplers will not give significantly different measured exposures. The effect on exposure measurement of placing the samplers on either side of the head was variable; consequently, sampling position cannot be meaningfully defined. All samplers collected significant amounts of grinding dust. Therefore, gravimetric determination of welding fume exposure in atmospheres containing grinding dust will be inaccurate. The use of a new size selective sampler can, to some extent, be used to give a more accurate estimate of exposure. The reliability of fume analysis data of welding consumables has caused concern; and the reason for differences that existed between the material safety data sheet and the analysis of fume samples collected requires further investigation.

Primary subcutaneous mucormycosis (zygomycosis): a case report

A case of mycormycosis presenting primarily as a subcutaneous mass of the left leg in an immunocompetent individual is described. The mass that was diagnosed initially as a non-specific foreign body granulomatous process recurred a year later. Histopathological examination of the primary and recurrent lesions revealed partly degenerated hyphae associated with acute necrotizing and chronic granulomatous inflammation. Histomorphological features of primary subcutaneous mucormycosis without predisposing factors have not been previously reported.