Efflux transporters in rat placenta and developing brain: transcriptomic and functional response to paracetamol

Adenosine triphosphate binding cassette (ABC) transporters transfer lipid-soluble molecules across cellular interfaces either directly or after enzymatic metabolism. RNAseq analysis identified transcripts for ABC transporters and enzymes in rat E19, P5 and adult brain and choroid plexus and E19 placenta. Their functional capacity to efflux small molecules was studied by quantitative analysis of paracetamol (acetaminophen) and its metabolites using liquid scintillation counting, autoradiography and ultra-performance liquid chromatography coupled with tandem mass spectrometry (UPLC-MS/MS). Animals were treated acutely (30 min) and chronically (5 days, twice daily) with paracetamol (15 mg/kg) to investigate ability of brain and placenta barriers to regulate ABC transport functionality during extended treatment. Results indicated that transcripts of many efflux-associated ABC transporters were higher in adult brain and choroid plexus than at earlier ages. Chronic treatment upregulated certain transcripts only in adult brain and altered concentrations of paracetamol metabolites in circulation of pregnant dams. Combination of changes to metabolites and transport system transcripts may explain observed changes in paracetamol entry into adult and fetal brains. Analysis of lower paracetamol dosing (3.75 mg/kg) indicated dose-dependent changes in paracetamol metabolism. Transcripts of ABC transporters and enzymes at key barriers responsible for molecular transport into the developing brain showed alterations in paracetamol pharmacokinetics in pregnancy following different treatment regimens.

Relationships between the integrity and function of lumbar nerve roots as assessed by diffusion tensor imaging and neurophysiology

Purpose

Diffusion tensor imaging (DTI) has shown promise in the measurement of peripheral nerve integrity, although the optimal way to apply the technique for the study of lumbar spinal nerves is unclear. The aims of this study are to use an improved DTI acquisition to investigate lumbar nerve root integrity and correlate this with functional measures using neurophysiology.

Methods

Twenty healthy volunteers underwent 3 T DTI of the L5/S1 area. Regions of interest were applied to L5 and S1 nerve roots, and DTI metrics (fractional anisotropy, mean, axial and radial diffusivity) were derived. Neurophysiological measures were obtained from muscles innervated by L5/S1 nerves; these included the slope of motor-evoked potential input-output curves, F-wave latency, maximal motor response, and central and peripheral motor conduction times.

Results

DTI metrics were similar between the left and right sides and between vertebral levels. Conversely, significant differences in DTI measures were seen along the course of the nerves. Regression analyses revealed that DTI metrics of the L5 nerve correlated with neurophysiological measures from the muscle innervated by it.

Conclusion

The current findings suggest that DTI has the potential to be used for assessing lumbar spinal nerve integrity and that parameters derived from DTI provide quantitative information which reflects their function.

The triple-phase CT image appearance of post-irradiated livers

Objective To evaluate the sequential CT appearance of the liver after hepatic irradiation and to investigate the correlation between CT findings and radiation-induced hepatic injury.

Material and Methods: The triple-phase CT images of 18 patients with hepatocellular carcinomas (HCC) after hepatic irradiation were retrospectively reviewed (in total 41 CT studies). The high-dose region within the liver was defined as the area receiving more than 90% of the prescribed irradiation dose. The mean radiation dose was 55.5 Gy. Density changes and patterns of enhancement in the high-dose region were classified as three types: type I, constant low-density change in all phases; type II, low-density change in both pre-contrast and arterial phases, and iso-density change in the portal phase; type III, low- or iso-density change in the pre-contrast phase, low- or high-density change in the arterial phase, and persistent high-density change in the portal phase. The interval between completion of radiotherapy and the CT examinations ranged from 9 to 469 days, with a mean of 147 days.

Results: Nine of the 41 CT studies presented with type I, 9 with type II, and 16 with type III CT findings. The mean interval between completion of radiotherapy and the appearance of types I, II, and III CT findings were 74, 183, and 220 days, respectively. The interval was significantly shorter for type I findings than for type II and type III. The difference in interval was not significant between type II and type III. A type I finding with constant low-density change in the high-dose region of the liver was the most common pattern of CT findings within the first 3 months after hepatic irradiation. Either types II or III findings were frequently seen after 3 months.

Conclusion: The sequential CT appearance and the density changes may indicate correlation with the pathogenesis of veno-occlusive disease.

Voluntary activation of trunk extensors appears normal in young adults who have recovered from low back pain

BACKGROUND

Low back pain (LBP) is associated with alterations in control of trunk movements and changes within central nervous system (CNS). Evidence shows that some of these alterations within the CNS are reversible when the symptoms are relieved, whereas other shows the opposite. Therefore, the purpose of the current study was to investigate whether alterations in voluntary activation (VA) of central neural drive, as assessed using twitch interpolation to measure VA, are present in subjects with a history of low back pain (HLBP), who are free from pain at the time of experiment.

METHODS

Twelve adults with HLBP and 12 controls participated. Bilateral electromyographic recordings were obtained from erector spiane muscles at two vertebral levels (T12 and L4) and from rectus abdominis. Participants performed a series of brief isometric back extensions (50-100% maximum voluntary contraction) during which transcranial magnetic stimulation was delivered. The sizes of the evoked (superimposed) twitches were measured using dynamometry and VA was derived. The amplitude of motor evoked potentials (MEPs) and duration of cortical silent period (CSP) in erector spinae muscles were calculated; questionnaires were used to evaluate disability, levels of physical activity, quality of life and pain.

RESULTS

The level of VA was not significantly different between HLBP and control groups. Additionally, there were no between-group differences in the time-to-peak amplitudes of the twitches, MEP amplitudes or duration of CSP.

CONCLUSIONS

The ability to voluntarily activate back extensor muscles maximally does not appear to be impaired in subjects with a history of LBP during pain-free episodes.

Impaired neural drive in patients with low back pain

BACKGROUND

Control of trunk movement relies on the integration between central neuronal circuits and peripheral skeletomuscular activities and it can be altered by pain. There is increasing evidence that there are deficits within the central nervous system controlling the trunk muscles in people with low back pain (LBP). However, it is unclear how LBP impacts upon neural drive to back muscles at different levels of voluntary contraction. Therefore, the purpose of this study was to investigate if neural drive is impaired in these patients.

METHODS

Seventeen patients with LBP and 11 healthy controls were recruited. Bilateral electromyographic (EMG) recordings were obtained from the erector spinae (ES) muscles at two vertebral levels (T12 and L4). Participants performed a series of brief isometric back extensions (50-100% maximum voluntary contraction - MVC), during which transcranial magnetic stimulation was delivered. The size of the evoked (superimposed) twitch was measured using dynamometry.

RESULTS

The size of the superimposed twitch decreased linearly with increasing contraction strength in the controls; however, this linear relationship was not observed in the patients. Additionally, patients had larger superimposed twitches and longer time-to-peak amplitudes during MVCs than those observed in controls. Furthermore, patients had lower MVC and root-mean-square EMG activity of ES muscles during MVCs.

CONCLUSIONS

A decline of central neural drive to the back muscles at high level of voluntary contraction was observed in patients with LBP. These results suggest that it might be pertinent to include neuromuscular facilitation programmes and therapeutic exercise utilizing high voluntary contractions for patients with LBP.

Peritoneal serous papillary carcinoma: a reappraisal of CT imaging features and literature review

We evaluated the imaging features of primary serous peritoneal carcinoma (PSPC) on computed tomography (CT) and reviewed the literature. Preoperative CT images of 11 women with PSPC were retrospectively reviewed. The clinical presentations and serum levels of CA-125 were recorded. Special attention was paid to the operative and histopathologic findings of the ovaries. Imaging features were correlated with those in the literature. An elevation of serum CA-125 was found in 91% of cases. The CT findings included ascites (82%), peritoneal nodules or masses (73%), and omental nodules or omental caking (64%). Absence of an overt ovarian mass was observed in 64% of cases. The clinical manifestations and imaging features in our patients were consistent with those in the literature. Eighty-five percent of the ovaries in our study were superficially involved by PSPC in histopathologic examination. In none of our cases could the ovarian size be clearly assessed in the CT images. In conclusion, the presence of diffuse peritoneal disease and the absence of an ovarian mass on CT and an elevation of serum CA-125 level is suggestive of PSPC. However, in our experience, the evaluation of ovarian morphology and size by CT alone may not be as reliable.

The triple-phase CT image appearance of post-irradiated livers

OBJECTIVE

To evaluate the sequential CT appearance of the liver after hepatic irradiation and to investigate the correlation between CT findings and radiation-induced hepatic injury.

MATERIAL AND METHODS

The triple-phase CT images of 18 patients with hepatocellular carcinomas (HCC) after hepatic irradiation were retrospectively reviewed (in total 41 CT studies). The high-dose region within the liver was defined as the area receiving more than 90% of the prescribed irradiation dose. The mean radiation dose was 55.5 Gy. Density changes and patterns of enhancement in the high-dose region were classified as three types: type I, constant low-density change in all phases; type II, low-density change in both pre-contrast and arterial phases, and iso-density change in the portal phase; type III, low- or iso-density change in the pre-contrast phase, low- or high-density change in the arterial phase, and persistent high-density change in the portal phase. The interval between completion of radiotherapy and the CT examinations ranged from 9 to 469 days, with a mean of 147 days.

RESULTS

Nine of the 41 CT studies presented with type I, 9 with type II, and 16 with type III CT findings. The mean interval between completion of radiotherapy and the appearance of types I, II, and III CT findings were 74, 183, and 220 days, respectively. The interval was significantly shorter for type I findings than for type II and type III. The difference in interval was not significant between type II and type III. A type I finding with constant low-density change in the high-dose region of the liver was the most common pattern of CT findings within the first 3 months after hepatic irradiation. Either types II or III findings were frequently seen after 3 months.

CONCLUSION

The sequential CT appearance and the density changes may indicate correlation with the pathogenesis of veno-occlusive disease.

Optimizing production of polyunsaturated fatty acids in Marchantia polymorpha cell suspension culture

Chlorophyll containing callus cells of Marchantia polymorpha are able to grow under dim illumination in the presence of an organic carbon source and retain the ability to produce polyunsaturated fatty acids (PUFA), including C(20) fatty acids. Highest PUFA production was achieved using 2,4-dichlorophenoxyacetic acid as growth regulator. Inoculum size, illumination intensity, organic carbon source, and ferrous ion are the major factors affecting PUFA productivity. Maximum PUFA productivity is attained under low light intensity, with a photon flux density ca. 20 micromol m(-2) s(-1). Optimal inoculum size and glucose concentration for PUFA production are 8-12% and 20-30 g l(-1), respectively. Ferrous ion can promote PUFA productivity by increasing the intracellular lipid content. Highest productivities for PUFA, arachidonic acid (ARA), and eicosapentaenoic acid (EPA) were 35.0+/-2.1, 6.7+/-0.4 and 6.6+/-0.4 mg l(-1) day(-1), respectively. PUFA production in the M. polymorpha culture is shown to be strongly growth-associated. Environmental stress (osmotic pressure) is ineffective in promoting PUFA productivity. Chitosan, an elicitor, also has no effect on intracellular PUFA content in cultured M. polymorpha cells.

Quantitative structure-activity relationships for the pre-steady-state inhibition of cholesterol esterase by 4-nitrophenyl-N-substituted carbamates

4-Nitrophenyl-N-substituted carbamates (1-6) are the pseudo-substrate inhibitors of porcine pancreatic cholesterol esterase. Thus, the first step of the inhibition (Ki step) is the formation of the enzyme inhibitor tetrahedral adduct and the second step of the inhibition (kc) is the formation of the carbamyl enzyme. The formation of the enzyme inhibitor tetrahedral adduct is further divided into two steps, the formation of the enzyme-inhibitor complex with the dissociation constant, KS, at the first step and the formation of the enzyme-inhibitor tetrahedral adduct from the complex at the second step. The two-step mechanism for the formation of the enzyme-inhibitor tetrahedral adduct is confirmed by the pre-steady-state kinetics. The results of quantitative structure-activity relationships for the pre-steady-state inhibitions of cholesterol esterase by carbamates 1-6 indicate that values of -logKs and logk2/k-2 are correlated with the Taft substituent constant, sigma*, and the rho* values from these correlations are -0.33 and 0.1, respectively. The negative rho* value for the -logKS-sigma*-correlation indicates that the first step of the two-step formation of the enzyme-inhibitor tetrahedral adduct (KS step) is the formation of the positive enzyme inhibitor complex. The positive rho* value for the logk2/k-2 -sigma*-correlation indicates that the enzyme inhibitor tetrahedral adduct is more negative than the enzyme inhibitor complex. Finally, the two-step mechanism for the formation of the enzyme inhibitor tetrahedral adduct is proposed according to these results. Thus, the partially positive charge is developed at nitrogen of carbamates 1-6 in the enzyme-inhibitor complex probably due to the hydrogen bonding between the lone pair of nitrogen of carbamates 1-6 and the amide hydrogen of the oxyanion hole of the enzyme. The second step of the two-step formation of the enzyme-inhibitor tetrahedral adduct is the nucleophilic attack of the serine of the enzyme to the carbonyl group of carbamates 1-6 in the enzyme-inhibitor complex and develops the negative-charged oxygen in the adduct.

Topography of low skin resistance points (LSRP) in rats

Based on the electrical properties of the skin, a method employing the unijunction transistor (UJT) relaxation oscillator for detecting low skin resistance points (LSRP) was developed in this study. By means of this instrumentation, the topography of the LSRP in Wistar rats was developed. All the LSRP in the rats were found to be bilaterally and symmetrically distributed except those points located on the dorsal midline (i.e., governor vessel, GV) and the ventral midline (i.e., conception vessel, CV). The resistances of the LSRP on these two major vessels, including 14 CV points and 17 GV points of six rats were experimentally determined to be in the ranges of 179.4 +/- 41.2 K omega and 152.5 +/- 32.2 K omega, respectively. The resistances of the GV points were found in general to be lower than those of the CV points. Most non-LSRP, on the other hand, exhibited resistances of greater than 420 K omega. It is noted that the resistances of most LSRP increased yet still retained a separate identity within thirty minutes after the death of the animals, but the low resistance properties of some LSRP gradually disappeared thereafter and could not be detected by the relaxation oscillator.

Inhibition of Japanese encephalitis virus infection by nitric oxide: antiviral effect of nitric oxide on RNA virus replication

The antiviral effects of nitric oxide (NO) on Japanese encephalitis virus (JEV), a member of the family Flaviviridae, were investigated in this study. In vitro, inhibition of replication of JEV in gamma interferon-activated RAW 264.7 murine macrophages was correlated to cellular NO production. When cocultured with infected murine neuroblastoma N18 cells, gamma interferon-activated RAW 264.7 cells also efficiently hindered JEV replication in contiguous bystanders, and this anti-JEV effect could be reversed by an NO synthase (NOS) inhibitor, N-monomethyl-L-arginine acetate. In vivo, the mortality rate increased as the NOS activity of JEV-infected mice was inhibited by its competitive inhibitor, N-nitro-L-arginine methyl ester. Moreover, when an organic donor, S-nitro-N-acetylpenicillamine (SNAP), was used, the NO-mediated antiviral effect was also observed in primarily JEV-infected N18, human neuronal NT-2, and BHK-21 cells, as well as in persistently JEV-infected C2-2 cells. These data reaffirm that NO has an effective and broad-spectrum antimicrobial activity against diversified intracellular pathogens. Interestingly, the antiviral effect of NO was not enhanced by treatment of N18 cells with SNAP prior to JEV infection, a measure which has been shown to greatly increase the antiviral effect of NO in infection by vesicular stomatitis virus. From biochemical analysis of the impact of NO on JEV replication in cell culture, NO was found to profoundly inhibit viral RNA synthesis, viral protein accumulation, and virus release from infected cells. The results herein thus suggest that NO may play a crucial role in the innate immunity of the host to restrict the initial stage of JEV infection in the central nervous system.

Effect of workers' shoe wear on objective and subjective assessment of slipperiness

Subjective rating of slipperiness tests were conducted for 12 male industrial workers on three slippery surfaces, with poor or good lighting conditions, and with new or workers' own old shoes. A strain gauge force platform was used to evaluate dynamic coefficient of friction (COF) of shoes for the same surface conditions representing objective measurements. The shoe wear, available tread pattern, and hardness of old shoes were determined by instruments including a digital caliper, a digitizer, and a durometer, respectively. The surface effect was found to be highly significant on subjective ratings as well as dynamic COF (p < 0.0001). The correlation between dynamic COF values and subjective ratings was significant only for old shoes under medium oily conditions (r = 0.55, p < 0.04). For a slightly oily surface, decreasing the percent of tread available significantly increased dynamic COF values (p < 0.016). In addition, the effect of increased shoe hardness significantly increased the available tread pattern when only the data from the most deteriorated old shoes were included in the analyses (p < 0.004). These results emphasize the need to consider subjective assessment of slipperiness as a valid way to evaluate floor slipperiness. Further study is needed to (1) evaluate the effects of physical fatigue due to workload on subjective assessment of slipperiness and workers' ability to assess slipperiness during task performance; (2) consider the effect of available shoe tread on COF values and slip potential; and (3) determine if guidelines should be developed regarding when work shoes should be replaced to reduce slip and fall injuries.

[Screening and rapid identification of Bacillus thuringiensis mutants]

Mutants of Bacillus thuringiensis subsp. kurstaki NTU 9 and Bt 158, which were isolated previously for using the diamondback moth as a target insect in Taiwan, were screening by either protein electrophoresis of intracellular proteins or enzyme-linked immunosorbent assay (ELISA). The optimal conditions of effective protein electrophoresis were (1) 24-hour cells harvested from nutrient broth were crashed by petite glass beads followed by centrifugation. And (2) the supernatant pretreated by heating at 60 degrees C for 2 minutes was electrophoresed with 7.5% native PAGE at 110 voltages. On ELISA, the antiserum used was obtained from rabbits immunized with Bt 158 crystal protein. Optimal antigen coating concentration of ELISA, attained by chequer-board titration method, was 10 micrograms/ml. Antigens (crystal protein) in samples were detected by competitive inhibition method with antiserum diluted to 10(4) fold. By using protein electrophoresis and ELISA methods, two isolates A 71 and BN 11, were denoted respectively as qualitative and quantitative mutants of Bacillus thuringiensis.

Enterogenous cyst of the fourth ventricle: case report

The authors present an intracranial enterogenous cyst of the fourth ventricle in a Chinese woman having symptoms of headache, dizziness and vertigo for approximately six months. A computerized tomography study of the brain disclosed a low density lesion within the fourth ventricle. A cystic tumor was completely removed and a histopathological examination diagnosed it is an enterogenous cyst; a rare lesion. During the post-operative follow-up, her symptoms gradually resolved and she was free of complaints within two years.