A Spin-on Dielectric Material for High Aspect Ratio Gap Fill

This communication describes the results of a potential spin-on glass (SOG) solution for narrow and high aspect ratio trench fill in both shallow trench isolation (STI) and premetal dielectric (PMD) applications. We have focused our development work on a hydrogen silsesquioxane (HSQ, (HSiO3/2)n) material, which offers the advantage of a carbon free gap fill solution. The main challenge for carbon-free SOG materials is to achieve material densification in the nano-scale gaps during thermal processing that of the gap filled material during the wet cleaning steps. This paper reports some approaches and findings on material densification in the nano-scale gaps and the results of subsequent wet etch tests.

Bronchial hyperresponsiveness to methacholine and adenosine 5'-monophosphate, and the presence and degree of atopy in young children with asthma

BACKGROUND

Bronchial hyperresponsiveness (BHR) is a characteristic feature of asthma, and is usually measured by bronchial challenges using direct or indirect stimuli. The relationship between atopy and BHR remains to be clarified, particularly in a population selected for asthma. Furthermore, data for young children are limited, although asthma frequently occurs in early childhood.

OBJECTIVE

The aim of this study was to investigate methacholine (direct stimulus) and adenosine 5'-monophosphate (AMP) (indirect stimulus) responsiveness according to the presence and degree of atopy in young children with asthma.

METHODS

A retrospective analysis of data from 122 preschool children (median age [range]: 5.3 years [4.0-6.8]) presenting with the diagnosis of asthma was performed. These children were characterized by skin-prick tests (SPTs) and bronchial challenges with methacholine and AMP, using a modified auscultation method. The end-point concentration, resulting in audible wheezing and/or oxygen desaturation, was determined for each challenge. Atopy was defined by at least one positive reaction to SPTs, and its degree was assessed using serum total IgE levels, number of positive SPTs, and atopic scores (sum of graded weal size).

RESULTS

Atopic patients (n=97) had a significantly lower AMP end-point concentration than non-atopic patients (n=25), whereas the methacholine end-point concentration was not different between the two groups. Among the atopic patients, there was no association between the methacholine end-point concentration and any of the atopy parameters. By contrast, a significant association was found between the AMP end-point concentration and the degree of atopy reflected in serum total IgE and atopic scores (χ² test for trend, P=0.001, 0.003, respectively).

CONCLUSION AND CLINICAL RELEVANCE

Young children with atopic asthma had a significantly greater AMP responsiveness than those with non-atopic asthma, whereas methacholine responsiveness was not significantly different between the two groups. The degree of atopy appeared to be an important factor in AMP responsiveness, but not in methacholine responsiveness, and thus might be a marker of airway inflammation in asthma.

Diffuse intraabdominal fibrosis and inflammation mimicking peritoneal carcinomatosis recurred after surgery for borderline ovarian tumor misdiagnosed by 18F-fluorodeoxyglucose-positron emission tomography

BACKGROUND

18F-fluorodeoxyglucose-positron emission tomography (FDG-PET) adds to conventional imaging in the detection and staging of peritoneal carcinomatosis.

CASE REPORT

Herein we report a 27-year-old woman with multiple intraperitoneal masses detected by 18F-FDG-PET, suggesting peritoneal carcinomatosis. She had undergone laparoscopic unilateral oophorectomy for a left ovarian mucinous borderline tumor approximately five years before. Based on imaging and intraoperative findings, multiple intraabdominal masses strongly suggested peritoneal recurrence from a previous ovarian borderline tumor, but it finally proved to be inflammation and fibrosis on histopathologic examination.

CONCLUSION

Although 18F-FDG-PET is well known to be a highly sensitive imaging tool for identification of peritoneal carcinomatosis, FDG uptake is not tumor-specific. Therefore, the possibility of a false-positive diagnosis due to benign conditions, such as inflammation, should always be taken into consideration.

Non-destructive evaluation of nano-sized structure of thin film devices by using small angle neutron scattering

Nano-sized multi-layers copper-doped SrZrO3, platinum (Pt) and silicon oxide (SiO2) on silicon substrates were prepared by dense plasma focus (DPF) device with the high purity copper anode tip and analyzed by using small angle neutron scattering (SANS) to establish a reliable method for the non-destructive evaluation of the under-layer structure. Thin film was well formed at the time-to-dip of 5 microsec with stable plasma of DPF. Several smooth intensity peaks were periodically observed when neutron beam penetrates the thin film with multi-layers perpendicularly. The platinum layer is dominant to intensity peaks, where the copper-doped SrZnO3 layer next to the platinum layer causes peak broadening. The silicon oxide layer has less effect on the SANS spectra due to its relative thick thickness. The SANS spectra shows thicknesses of platinum and copper-doped SrZnO3 layers as 53 and 25 nm, respectively, which are well agreement with microstructure observation.

Metastatic cervical adenocarcinoma mimicking retroperitoneal sarcoma of the psoas muscle on imaging

BACKGROUND

The incidence of bone metastasis is low in metastatic cervical cancer, especially in the case of adenocarcinoma. Incidental finding of a mass located in an unusual metastatic site in the absence of identifiable primary tumor often results in a difficult diagnostic problem.

CASE REPORT

We report the case of a 59-year-old woman presenting left-sided foot drop as her initial symptom. At first, after performing lumbar spine magnetic resonance imaging (MRI), a huge paravertebral mass with ipsilateral psoas muscle involvement suggesting retroperitoneal sarcoma was identified. However, cervical punch biopsy and sono-guided paravertebral mass biopsy revealed cervical adenocarcinoma with lumbar spinal metastasis.

CONCLUSION

Although rare, a neurological symptom such as foot drop, not vaginal symptoms, in a woman may be a first manifestation of metastatic cervical cancer, especially in spinal metastasis. Furthermore, any abnormal lesion should not be ignored because of the possibility of metastasis from the primary malignancy, especially in the current case of cervical adenocarcinoma, so a complete evaluation is always mandatory.

Feasibility of nonthermal atmospheric pressure plasma for intracoronal bleaching

AIM

To investigate the effect of nonthermal atmospheric pressure plasma on intracoronal tooth bleaching in blood stained human teeth.

METHODOLOGY

Forty extracted single-root and blood stained human teeth were used. The teeth were randomly divided into two groups (n=20): group 1 received 30% HP activated by nonthermal atmospheric pressure plasma in the pulp chamber for 30 min, whilst group 2 received 30% HP alone in the pulp chamber for 30 min. The overall colour changes (ΔE) were assessed using the Commission Internationale de L'Eclairage (CIE) Lab Colour System. The data were analysed using Student's t-test to determine the significant differences.

RESULTS

The temperature of all teeth was maintained at approximately 37 °C during plasma bleaching. The plasma treatment with 30% HP resulted in significantly higher bleaching efficacy compared to 30% HP alone in discoloured teeth (P<0.05). The average ΔE values of group 1 and group 2 were 9.24 (0.37) and 4.47 (1.62), respectively, at 30 min.

CONCLUSIONS

The application of nonthermal atmospheric pressure plasma to intracoronal bleaching could be a novel and efficient therapy in the bleaching of haemorrhagically stained teeth.

Bronchial hyperresponsiveness to methacholine/AMP and the bronchodilator response in asthmatic children

Bronchodilator response (BDR) is assessed to estimate the reversibility of airflow obstruction. Bronchial hyperresponsiveness (BHR) is a characteristic feature of asthma and is usually measured by means of bronchial challenges using direct or indirect stimuli. The aim of the present study was to compare BHR to methacholine (direct) and that to adenosine 5'-monophosphate (AMP) (indirect) with regard to their relationships to BDR in asthmatic children. Methacholine and AMP challenge tests were performed on 138 children with mild-to-moderate asthma, and the provocative concentration causing a 20% decline in forced expiratory volume in 1 s (FEV₁) (PC₂₀) was determined for each challenge. BDR was calculated as the change in FEV(1), expressed as a percentage of the initial value, after inhalation of 400 μg salbutamol. Methacholine PC₂₀ correlated significantly but weakly with BDR (r = -0.254; p = 0.003). However, there was a significant and strong correlation between AMP PC₂₀ and BDR (r = -0.489; p = 0.000). For AMP PC₂₀, the relationship was closer than for methacholine PC₂₀ (p = 0.024 for comparison between correlation coefficients). The same figures were observed when BDR was expressed as a percentage of the predicted value. A stronger correlation of BDR with AMP PC₂₀ than with methacholine PC₂₀ suggests that BDR may be better reflected by BHR as assessed by AMP challenge than by methacholine challenge.

Variation in Sodium Chloride Resistance of Cenococcum geophilum and Suillus granulatus Isolates in Liquid Culture

We studied the resistance of Cenococcum geophilum and Suillus granulatus isolates to NaCl during growth under axenic culture conditions. C. geophilum isolates displayed variations in NaCl resistance; mycelial growth of most isolates was inhibited above 200mM. All isolates of S. granulatus were tolerant to high NaCl content.

Fatal cerebral hemorrhage associated with autonomic hyperreflexia during surgery in the prone position in a quadriplegic patient: a case report

Intracerebral hemorrhage is an unusual complication of autonomic hyperreflexia (AHR), which can be fatal if massive bleeding occurs with subsequent brain herniation. Episodes of AHR are most often triggered by bladder and rectal distention. We present a case of a 45-year-old quadriplegic male who suffered left basal ganglia and thalamic hemorrhage associated with AHR during surgery for pressure sore defects in the prone position under local anesthesia. Early recognition and removal of triggering factors of AHR failed to bring his blood pressure under control. The patient continued to deteriorate neurologically and died 9 days after the attack. A preventive measure rather than episodic treatment of AHR may be of paramount importance to avoid life-threatening complications, especially when a patient with a history of AHR is undergoing surgery in the prone position.

Second-order schedules with fixed-ratio components: variation of component size

Key pecking by pigeons was reinforced with food under second-order schedules with fixed-ratio units. A constant total number of key pecks was required for reinforcement under each condition, but the size and, inversely, number of fixed-ratio components were varied. The total response requirement of 256 pecks was divided into fixed-ratio units of 128, 64, 32, 8, and 2 responses. A brief stimulus, which always preceded food reinforcement, was presented upon completion of each fixed-ratio unit. Under most conditions, the pattern of within-unit responding was typical of that under simple fixed-ratio schedules. Overall response rate was an inverted U-shaped function of component size. That is, response rates were highest under moderate sized units (fixed ratio 128 and 64). This relationship is consistent with previous determinations of rate as a function of fixed-ratio value for simple fixed-ratio schedules.

Expression of cell-cycle regulators (cyclin D1, cyclin E, p27kip1, p57kip2) in papillary thyroid carcinoma

Objective: To evaluate the expression of cell-cycle regulators in papillary thyroid carcinoma in relation to lymph node metastatic features, and to determine whether immunohistochemical staining of cell-cycle markers can predict lymph node metastasis.

Study Design: Cross-sectional study of prior surgical specimens.

Setting: Academic tertiary referral center.

Subjects and Methods: We reviewed the clinical records of patients who had undergone surgery for thyroid cancer and follicular adenoma between January 2005 and May 2008 at our clinic. Among these cases, 92 patients, comprising 28 patients with follicular adenoma, 32 with papillary thyroid carcinoma without lymph node metastasis, and 32 with papillary thyroid carcinoma with lymph node metastasis, were selected randomly. Formalin-fixed, paraffin-embedded tissues from the 92 patients were immunohistochemically stained for cyclin D1, cyclin E, p27kip1, and p57kip2, and protein expression levels were quantified and compared among the groups.

Results: Tumor specimens from the papillary thyroid carcinoma group had significantly higher expression levels of cyclin D1 and cyclin E, and cytoplasmic expression of p57kip2 than the other two groups ( P < 0.05). In particular, all malignant cases expressed cyclin D1, and cytoplasmic p57kip2 was expressed only in malignant cases. Furthermore, differences in the grade of cyclin D1 expression according to lymph node metastasis were statistically significant ( P < 0.05).

Conclusion: Our results suggest that immunohistochemistry of certain cell-cycle regulators may be helpful in the diagnosis of papillary thyroid carcinoma, and that cyclin D1 in particular may be a useful marker for evaluating lymph node metastasis.

Balloon kyphoplasty versus vertebroplasty for treatment of osteoporotic vertebral compression fracture: a prospective, comparative, and randomized clinical study

Bone pain and spinal axial deformity are major concerns in aged patients suffering from osteoporotic vertebral compression fracture (VCF). Pain can be relieved by vertebroplasty or kyphoplasty procedures, in which the compressed vertebral body is filled with substitutes. We randomly assigned 100 patients with osteoporotic compression fracture at the thoraco-lumbar (T-L) junction into two groups: vertebroplasty and kyphoplasty; we used polymethylmethacrylate (PMMA) as the bone filler. Pain before and after treatment was assessed with visual analog scale (VAS) scores and vertebral body height and kyphotic wedge angle were measured from reconstructed computed tomography images. More PMMA was used in the kyphoplasty group than in the vertebroplasty group (5.56 +/- 0.62 vs. 4.91 +/- 0.65 mL, p < 0.001). Vertebral body height and kyphotic wedge angle of the T-L spine were also improved (p < 0.001). VAS pain scores did not differ significantly between the treatment groups. The duration of follow-up was 6 months. Two patients in the kyphoplasty group had an adjacent segment fracture. In terms of clinical outcome there was little difference between the treatment groups. Thus, owing to the higher cost of the kyphotic balloon procedure, we recommend vertebroplasty over kyphoplasty for the treatment of osteoporotic VCFs.

INTRODUCTION

Spinal axial deformities are major concerns in aged patients suffering from osteoporotic vertebral compression fracture. Pain may be relieved by vertebroplasty or kyphoplasty. We investigated the radiological and clinical outcomes of these procedures.

METHODS

One hundred cases of VCF at the thoraco-lumbar junction were randomly assigned into two groups: vertebroplasty or kyphoplasty (50 cases each). We used polymethylmethacrylate as the bone filler. Pain before and after treatment was assessed with visual analog scale scores and vertebral body height and kyphotic wedge angle were measured from reconstructed computed tomography images.

RESULTS

More PMMA was used in the kyphoplasty group than in the vertebroplasty group (5.56 +/- 0.62 vs. 4.91 +/- 0.65 mL, p < 0.001). Vertebral body height and kyphotic wedge angle of the T-L spine were also improved (p < 0.001). VAS pain scores did not differ significantly between the treatment groups. The duration of follow-up was 6 months. Two patients in the kyphoplasty group had an adjacent segment fracture.

CONCLUSIONS

In terms of clinical outcome there was little difference between the treatment groups. Thus, with the higher cost of the kyphotic balloon procedure, we recommend vertebroplasty over kyphoplasty for the treatment of osteoporotic VCFs.

Primary serous papillary carcinoma of the peritoneum mimicking pelvic actinomycosis: a case report and brief literature review

Primary serous papillary carcinoma of the peritoneum is a rare tumor, histologically similar to primary ovarian carcinoma. Pelvic CT and MRI are helpful to diagnose primary carcinoma of the peritoneum. We present a case of primary serous carcinoma of the peritoneum mimicking pelvic actinomycosis in a 59-year-old woman. Pelvic CT and MRI suggested pelvic actinomycosis. Exploratory laparotomy was performed to remove the mass and the diagnosis was confirmed by pathology. A subtotal hysterectomy, left salpingo-oophorectomy and omentectomy were performed. Histopathology examination revealed peritoneal carcinomatosis and primary serous carcinoma of the peritoneum. Pelvic CT and MRI were limited in their ability to differentiate inflammation, such as actinomycosis, from primary carcinoma of the peritoneum.

Anatomical variations of the spinal accessory nerve and its relevance to level IIb lymph nodes

Objective: This study was conducted to identify anatomical variations of the spinal accessory nerve (SAN) in the upper neck, the landmark of the anterior and inferior border of level IIb, and to evaluate the nerve's effect on the border and the number of lymph nodes (LNs) in level IIb.

Study Design and Setting: Case series with planned data collection.

Subjects and Methods: A total of 181 neck dissections (NDs) were prospectively enrolled in this study. The relation between the SAN and adjacent structures (internal jugular vein [IJV], sternocleidomastoid muscle [SCM], cervical plexus) and the number of LNs in level IIb was investigated.

Results: The SAN crossed the IJV ventrally in 72 cases (39.8%) and dorsally in 104 cases (57.4%), and passed through the IJV in five cases (2.8%). The SAN ran along the inner surface of the SCM and sent branches to the SCM without penetration of the muscle in 83 cases (45.9%), whereas in 98 cases (54.1%) the nerve sent branches to the SCM by penetration. Cervical plexus contribution to the SAN was seen from C2 in 96 cases (53.1%), C2 and C3 in 69 cases (38.1%), and C3 in 16 cases (8.8%). The mean number of LNs of level IIa and level IIb was 6.5 and 8.2 in cases in which the SAN crossed the IJV ventrally, and 6.8 and 5.4 in dorsally crossing cases. LNs included in the neck level IIb in ventrally crossing SAN cases were significantly larger than the dorsally crossing cases ( P < 0.05).

Conclusions: Our results may help to minimize the incidence of injuring the SAN in the upper neck during ND. Neck level IIb would contain more LNs if the course of the nerve leans toward the ventral side.

Ectomycorrhizal fungal communities associated with Pinus thunbergii in the eastern coastal pine forests of Korea

We investigated the ectomycorrhizal (ECM) fungal colonization status of Pinus thunbergii mature trees and regenerating seedlings varying in age in coastal pine forests on the east coast of Korea. We established one 20 x 20-m plot at each of two study sites at P. thunbergii coastal forests in Samcheok. Fifty soil blocks (5 x 5 x 15 cm) were sampled at regular intervals, and ten P. thunbergii seedlings of age 0, 1-3, 3-5, and 5-10 years were sampled in each study plot. In total of 27 ECM fungal taxa, Cenococcum geophilum was dominant, followed by Russula sp., Sebacina sp., and unidentified Cortinuris sp. in mature trees. In 0-year-old seedlings, some fungal species such as Sebacina sp., C. geophilum, and unidentified Cortinarius sp. were dominant whereas only C. geophilum was dominant after 1 year, and there were no apparent succession patterns in ECM fungal compositions beyond a host age of 1 year. Most ECM fungal taxa that had colonized seedlings of each age class were also observed in roots of mature trees in each site. These taxa accounted for 86.7-100% and 96.4-98.4% of ECM abundance in seedlings and mature trees, respectively. The results indicate that the species composition of ECM fungal taxa colonizing seedlings of different age in forests is similar to that of surrounding mature trees. Our results also showed that C. geophilum is a common and dominant ECM fungus in P. thunbergii coastal forests and might play a significant role in their regeneration.

Gaussian-Taylor signal-to-noise ratio estimation for scanning electron microscope images

A new and robust parameter estimation technique, named Gaussian-Taylor interpolation, is proposed to predict the signal-to-noise ratio (SNR) of scanning electron microscope images. The results of SNR and variance estimation values are tested and compared with piecewise cubic Hermite interpolation, quadratic spline interpolation, autoregressive moving average and moving average. Overall, the proposed estimations for noise-free peak and SNR are most consistent and accurate to within a certain acceptable degree compared with the others.

Molecular cloning, characterization, and the response of manganese superoxide dismutase from the Antarctic bivalve Laternula elliptica to PCB exposure

Manganese superoxide dismutase (leMnSOD) cDNA was cloned from the Antarctic bivalve Laternula elliptica. The full-length cDNA of leMnSOD is 1238 bp in length and contains an open reading frame of 681 bp encoding 226 amino acid residues including a putative mitochondrial targeting peptide of 26 amino acids in the N-terminal region. The calculated molecular mass is 24.8 kDa with an estimated isoelectric point of 6.75. leMnSOD signatures from 185 to 192 (DVWEHAYY) and four conserved amino acids (H52, H11, D185, and H192) responsible for binding manganese were observed. Sequence comparison showed that leMnSOD had high levels of identity with MnSOD from Haliotis discus discus, Mizuhopecten yessoensis, and Crassostrea gigas (68%, 66%, and 59%, respectively). RT-PCR analysis revealed the presence of leMnSOD transcripts in all tissues examined. Quantitative real-time RT-PCR assay indicated that treatment with polychlorinated biphenyls (PCBs) significantly increased leMnSOD mRNA expression in an organ-, time-, and dose-dependent manner. The mRNA expression with exposure to PCBs at 0.1 and 10 ppb reached the highest level at 6 h and then recovered slightly from 6 to 48 h in the gill. In contrast, the expression of leMnSOD mRNA showed a different expression pattern related to PCB concentration in the digestive gland. The mRNA expression at 0.1 ppb PCBs increased up to 12 h and then decreased by 48 h, but increased immediately at 10 ppb PCBs. The leMnSOD was overproduced in Escherichia coli and purified. The recombinant leMnSOD showed maximum activity at pH 9.0, and it retained more than 50% of its original activity after incubation for 30 min at 40 degrees C.

Anaesthetic requirement and stress hormone responses in patients undergoing lumbar spine surgery: anterior vs. posterior approach

BACKGROUND

The intensity of nociceptive stimuli reflects the severity of tissue injury. The anaesthetic requirement and stress hormonal responses were determined to learn whether they differ according to different surgical approaches (anterior vs. posterior) during the spinal surgery.

METHODS

Patients undergoing lumbar spine surgery without neurological deficits were divided into two groups: one having posterior (n=13) and the other having anterior fusion (n=13). The end-tidal sevoflurane concentrations (ET(SEVO)) required to maintain the bispectral index score at 40-50 were determined. Mean arterial pressure (MAP), heart rate (HR), central venous pressure (CVP), serum osmolality and plasma concentrations of catecholamines, cortisol and vasopressin (AVP) were measured.

RESULTS

There were no differences in MAP, HR, CVP and serum osmolality between the groups. ET(SEVO) was higher in the anterior than in the posterior group (P<0.05). The plasma concentrations of norepinephrine and cortisol increased in both groups during the surgery, whereas those of epinephrine remained unchanged. AVP concentrations increased during the surgery in the anterior group, and remained unaltered in the posterior group. The anterior group needed more analgesics (P<0.01) during the first 1 h after the operation.

CONCLUSIONS

The anterior approach required a deeper level of anaesthesia while undergoing spinal surgery and more use of post-operative analgesics than the posterior approach. It was also associated with a more pronounced AVP release during the surgery.

Synthesis and photoluminescence properties of spherical fine red (Y(1-x-y)Gd(x)EU(y))BO3 (0 < or = x < or = 0.36, 0.06 < or = y < or = 0.13) phosphors using ultrasonic spray pyrolysis

The post-heat treated (Y(1-x-y)Gd(x)Eu(y))BO3 (0 < or = x < or = 0.36, 0.06 < or = y < or = 0.13) powders crystallized in a solution of (Y(1-x-y)Gd(x)Eu(y))BO3 with the hexagonal vaterite crystal structure, irrespective of composition. The lattice parameter of the (Y(0.9-x)Gd(x)Eu(0.1))BO3 (0 < or = x < or = 0.36) powders slightly increased with an increase in Gd content. The average powder sizes were sub-micron order and the powders showed relatively uniform size distribution and smooth surface. We obtained improved powder morphologies by adding organic additives such as ethylene glycol and citric acid. For the post-treated (Y(0.9-x)Gd(x)Eu(0.1))BO3, the emission intensity became stronger with increasing Gd content up to x = 0.27. In addition, for the post-treated (Y(0.73-y)Gd(0.27)Eu(y))BO3, the emission intensity gradually increased with Eu content up to y = 0.13. In particular, the emission intensity of the (Y(0.6)Gd)0.27)Eu(0.13))BO3 powders synthesized was higher than that of the commercial (Y,Gd)BO3:Eu3+ product.

How do we interpret an elevated carbohydrate antigen 19-9 level in asymptomatic subjects?

AIM

This prospective cohort study aimed to evaluate the etiology of elevated CA 19-9 levels and to present appropriate guidelines for the asymptomatic patients.

METHODS

Between January 2004 and March 2007, we enrolled consecutive asymptomatic patients who had elevated CA 19-9 levels >37 U/mL. To evaluate the etiology, the CA 19-9 level was rechecked and further studies were carried out. If the CA 19-9 level decreased to the normal range, or if it showed a decreasing trend, then it was monitored annually. Yet, if the CA 19-9 level showed an increasing trend, then the level was monitored at intervals of 1, 3, and 6 months until no evidence of malignancy was proven.

RESULTS

Of the 62,976 patients, 501 (0.8%) subjects showed an elevated CA 19-9 level. This prospective analysis was conducted on 353 subjects (70.5%) who were followed up for at least 6 months. Ten patients (2.8%) were diagnosed with malignancies. There were 97 patients (27.5%) with benign diseases and 246 patients (69.7%) were deemed non-specific.

CONCLUSIONS

CA 19-9 should not be used as a screening tool. In the case of a persistently elevated CA 19-9 level, further work-up for determining the etiology should be done.

Regulation of resin acid synthesis in Pinus densiflora by differential transcription of genes encoding multiple 1-deoxy-D-xylulose 5-phosphate synthase and 1-hydroxy-2-methyl-2-(E)-butenyl 4-diphosphate reductase genes

Pinus densiflora Siebold et Zucc. is the major green canopy species in the mountainous area of Korea. To assess the response of resin acid biosynthetic genes to mechanical and chemical stimuli, we cloned cDNAs of genes encoding enzymes involved in the 2-C-methyl-d-erythritol 4-phosphate (MEP) pathway (1-deoxy-d-xylulose 5-phosphate synthase (PdDXS), 1-deoxy-d-xylulose 5-phosphate reductoisomerase (PdDXR) and 1-hydroxy-2-methyl-2-(E)-butenyl 4-diphosphate reductase (PdHDR)) by the rapid amplification of cDNA ends (RACE) technique. In addition, we cloned the gene encoding abietadiene synthase (PdABS) as a marker for the site of pine resin biosynthesis. PdHDR and PdDXS occurred as two gene families. In the phylogenetic trees, PdDXSs, PdDXR and PdHDRs each formed a separate clade from their respective angiosperm homologs. PdDXS2, PdHDR2 and PdDXR were most actively transcribed in stem wood, whereas PdABS was specifically transcribed. The abundance of PdDXS2 transcripts in wood in the resting state was generally 50-fold higher than the abundance of PdDXS1 transcripts, and PdHDR2 transcripts were more abundant by an order of magnitude in wood than in other tissues, with the ratio of PdHDR2 to PdHDR1 transcripts in wood being about 1. Application of 1 mM methyl jasmonate (MeJA) selectively enhanced the transcript levels of PdDXS2 and PdHDR2 in wood. The ratios of PdDXS2 to PdDXS1 and PdHDR2 to PdHDR1 reached 900 and 20, respectively, on the second day after MeJA treatment, whereas the transcript level of PdABS increased twofold by 3 days after MeJA treatment. Wounding of the stem differentially enhanced the transcript ratios of PdDXS2 to PdDXS1 and PdHDR2 to PdHDR1 to 300 and 70, respectively. The increase in the transcript levels of the MEP pathway genes in response to wounding was accompanied by two orders of magnitude increase in PdABS transcripts. These observations indicated that resin acid biosynthesis activity, represented by PdABS transcription, was correlated with the selective transcriptions of PdDXS2 and PdHDR2. Introduction of PdDXS2, PdHDR1 and PdHDR2 rescued their respective knockout Escherichia coli mutants, confirming that at least these three genes were functionally active. Intracellular targeting of the green fluorescent protein fused to the N-terminal 100 amino acid residues of these genes in the Arabidopsis transient expression system showed that the proteins were all targeted to the chloroplasts. Our results suggest that the MEP pathway regulates resin biosynthesis in the wood of P. densiflora by differential transcription of the multiple PdDXS and PdHDR genes.

Chylous ascites: a late complication of intra-abdominal Mycobacterium avium complex immune reconstitution syndrome in HIV-infected patients

Chylous ascites related to Mycobacterium avium complex (MAC) in HIV-infected patients is rare, with only six cases reported in the English literature. We report a series of six cases from a single institution. During the past six years, chylous ascites was diagnosed in six (35%) of 17 AIDS patients, all of whom had previously been diagnosed with intra-abdominal MAC immune reconstitution syndrome (MAC-IRS). A review of medical records identified no other cases of chylous ascites among HIV-positive patients over the past 13 years (1994–2007), and the incidence was estimated at one in 2248 HIV-positive admissions. The ascitic fluid had a milky appearance and a median triglyceride level of 4.07 mmol/L (range 3.19–29.6 mmol/L) (360 mg/dL, range 282–2620 mg/dL). After a median follow-up of 20 months, five (83%) of six patients survived. Chylous ascites is a late complication of intra-abdominal MAC-IRS, and is usually associated with a favourable prognosis.