First Report of Lasiodiplodia theobromae Associated with Stem Canker of Almond in California

California is a major almond (Prunus dulcis) producer in the world. In September 2012, 2-year-old almond trees from an orchard in Fresno Co. with stem cankers were submitted for disease diagnosis. In a survey of the orchard, 12 ha (1,500 Nonpareil and 1,800 Monterey almond trees) of 48 ha trees had been killed apparently due to a stem canker. The cankers developed above the graft union, were covered with amber sap, and often girdled the trunk. Isolations made from tissues at the canker margins onto acidified potato dextrose agar (PDA) yielded two fungi, Macrophomina phaseolina (Tassi) Goid and Lasiodiplodia theobromae (Pat.) Griffon & Maubl (1). M. phaseolina and L. theobromae were isolated from eight and two of 10 cankered trees, respectively. No mixed infections were found. M. phaseolina isolates were characterized by gray hyphae that turned black with developing microsclerotia. L. theobromae isolates were characterized by white, aerial mycelium that turned mouse gray after 5 days. Young conidia were ellipsoidal, thick walled, initially hyaline, granular, and nonseptate; aged conidia were brown, 1-septate with longitudinal striations in the wall. Identity was confirmed by analyses of the internal transcribed spacer (ITS), β-tubulin 2 (BT2), and the translation elongation factor 1-alpha (TEF-1α) gene regions. BLAST searches at GenBank showed a high identity with reference sequences of type specimens both for M. phaseolina (isolates 7E64 to 7E69: ITS, 100%; BT2, 99%; TEF-1α, 99%) and L. theobromae (isolates 7E86 to 7E88: ITS, 99%; BT2, 99%; TEF-1α, 100%). Sequences of three gene regions were deposited as GenBank accessions KC357271 to KC357279 (ITS); KC357280 to KC357288 (BT2); and KC357289 to KC357297 (TEF-1α). The pathogenicity of M. phaseolina and L. theobromae to P. dulcis cultivars Butte, Carmel, Nonpareil, and Padre was investigated in an orchard at KARE using four isolates of M. phaseolina (7E64, 7E65, 7E66, and 7E69) and two isolates of L. theobromae (7E86 and 7E88). Ten 2-year-old branches per isolate from 7-year-old trees were inoculated with each isolate in late September 2012, after removing the bark with a 7-mm cork borer and placing a 7-day-old 7-mm-diameter agar plug bearing mycelium of each isolate directly into the fresh wound, mycelium side down. Ten additional branches of each of the four cultivars were inoculated with sterile PDA plugs and served as negative controls. Three weeks after inoculation, the average lesion produced by M. phaseolina on Butte, Carmel, Nonpareil, and Padre was 53, 52, 41, and 37 mm in length, respectively. Lesions produced by L. theobromae were 191, 206, 194, and 103 mm in length on the four cultivars, respectively. No disease lesion, only wounds, were produced on negative controls. Lesions produced by both pathogens were longer (P < 0.05) than wounds on the controls (average length 10 mm on all cultivars). Both L. theobromae isolates killed branches of cultivars Butte, Carmel, and Nonpareil in 2 weeks. M. phaseolina and L. theobromae were reisolated from the inoculated branches, and no fungus was reisolated from controls. Based on pathogenicity results, L. theobromae is more virulent to almond branches than M. phaseolina. To our knowledge, this is the second report of M. phaseolina (2) and the first report of L. theobromae as pathogens of P. dulcis trees in California. References: (1) A. Alves et al. Fungal Diversity 28:1, 2008. (2) P. Inderbitzin et al. Mycologia 102:1350, 2010.

Phylogeny of 16S rRNA and nifH genes and regulation of nitrogenase activity by oxygen and ammonium in the genus Paenibacillus

All Paenibacillus 16S rDNA sequences, except for that of Paenibacillus massiliensis T7, formed a coherent cluster, distinct from Gram-positive nitrogen-fixing Clostridium pasteurianum and Heliobacterium chlorum. All Paenibacillus NifH sequences formed two main clusters. Cluster I encompassing the NifH sequences from most of members of Paenibacillus spp., such as Paenibacillus azotofixans NifH1 and NifH2, Paenibacillus polymyxa and Paenibacillus macerans. Cluster II including only P. azotofixans NifH3. Curiously, three copies of nifH genes of Paenibacillus sabine T27 clustered within P. azotofixans cluster I (NifH1 and NifH2). The effect of O2 and ammonium on nitrogenase activity was studied with 14 different nitrogen-fixing Paenibacillus strains. The optimal oxygen concentration level for all Paenibacillus strains is in the 0 to 0.05% range, similar to that for Klebsiella pneumoniae. In all Paenibacillus strains, the highest nitrogenase activity is obtained in the condition of 0-0.1 mM NH4Cl and the increase of NH4CI from 0.1 to 5 mM caused a rapid inhibition of nitrogenase activity. However, the inhibition was reversible in the presence of 200 mM NH4Cl in some Paenibacillus strains. It is the first time to use almost all of the recognized nitrogen-fixing Paenibacilus spp. to investigate the phylogeny of 16S rRNA and nifH genes. The data that the inhibition of O2 and ammonium on nitrogenase acitivity will provide a base for studying the molecular regulatory mechanism of nitrogen fixation in the genus Paenibacillus.

Ultrastructural identification of interstitial cells of Cajal in hen oviduct

The interstitial cells of Cajal (ICC) are widely believed to be neuroeffector cells of smooth muscle activity in all tubular organs, including the oviduct. The avian oviduct involves the secretion, sheathing, and transportation of a large-sized egg, but there is no information available on ICC in this special organ. We have demonstrated the presence of ICC in different segments throughout the oviduct in the laying hen and provided details on their ultrastructure by transmission electron microscopy technique, for the first time. The observed ICC appeared bipolar and multipolar cells of different shapes, with varying nuclear morphologies, a thin rim of electron-dense cytoplasm, and an infrequent basal lamina. They showed moniliform primary processes with one or 2 secondary or terminal processes. We found ICC near smooth muscle cells, nerve fibers, and the epithelia, where they make specialized contacts in the form of close membrane associations or gap-like junctions and peg-and-socket-like junctions. Intricate labyrinthine-type networking contacts were also present in ICC processes. Moreover, we report for the first time, that ICC in avian oviduct make interdigitating contacts with the epithelium. Cytoplasmic organelles identified in ICC include numerous well-developed mitochondria, abundant rough endoplasmic reticulum, and dispersed intermediate filaments. Many caveolae and vesicles were also present. Golgi bodies and centrioles were rare. Fibroblasts, on the other hand, were distinct cells with larger cytoplasmic area, more rough endoplasmic reticulum, and less mitochondrial content. No basal lamina, intermediate filaments, or caveolae were present in fibroblasts. Their processes were shorter and showed no contacts with smooth muscle cells or nerves. We conclude that these ICC might also have a key role in the regulatory mechanisms of motility and transportation in the hen oviduct, as already proved in mammalian oviduct. Such role of ICC might also be responsible for the function of the muscular infundibulum, where the fertilization takes place, and that moves to surround the released ovum, failure of which results in the internal laying.

Intraoperative near-infrared indocyanine green-videoangiography (ICG-VA) and graphic analysis of fluorescence intensity in cerebral aneurysm surgery

We present our preliminary experience with intraoperative near-infrared indocyanine green-videoangiography (ICG-VA) and analysis of blood flow dynamics using fluorescence intensity assessment in cerebral aneurysm clipping surgery. Thirty-nine patients with 43 intracranial aneurysms underwent microsurgical clipping. Intraoperative ICG-VA was performed before and after clip application. An infrared fluorescence module integrated into a surgical microscope was used to visualize fluorescence in the surgical field and we recorded the emitted fluorescent light. An integrated analytical visualization tool simultaneously analyzed the video sequence and converted it into an intensity diagram, which allowed an objective evaluation of the results rather than the subjective assessment of fluorescence using ICG-VA. Overall, ICG-VA was performed 137 times. Incomplete clipping was detected in four patients, which allowed suitable adjustment to completely obliterate the aneurysm. In 12 patients, perforators arising close to, or from, the aneurysmal neck were identified in the surgical field. In three patients, the ICG-VA intensity diagram provided valuable information leading to modification of the primary surgical maneuver. ICG-VA provides high resolution images allowing real-time assessment of the blood flow in the parent artery and arterial branches, including the perforators. The intensity diagram is useful for providing a more objective record of the hemodynamics than the traditional ICG-VA, which relies more on subjective assessment and may allow interobserver variability. We conclude that ICG-VA, combined with the intensity diagram, can reduce the morbidity and complications associated with aneurysm clipping and improve patient outcomes.

The application of intraoperative near-infrared indocyanine green videoangiography and analysis of fluorescence intensity in cerebrovascular surgery

OBJECTIVE

To evaluate the usefulness and limitations of the intraoperative near-infrared (NIR) indocyanine green videoangiography (ICG-VA) and analysis of fluorescence intensity in cerebrovascular surgery.

METHODS

Forty-eight patients received ICG-VA during various surgical procedures from May 2010 to August 2010. Included among them were 45 cases of cerebral aneurysms and 3 cases of cerebral arteriovenous malformations (AVMs). The infrared fluorescence module integrated into the surgical microscope was used to visualize fluorescent areas in the surgical field. An integrated analytical visualization tool constantly analyzed the fluorescence video sequence and generated it in the form of an intensity diagram for objective interpretation.

RESULTS

Overall, the procedure of ICG VA was done 158 times in 48 patients. There was no adverse effect of ICG dye. In cerebral aneurysm cases, the images obtained were of high resolution. In 4 cases, incomplete clipping was detected by ICG-VA and allowed suitable adjustment to completely obliterate the aneurysm. In 3 aneurysm cases, the intensity diagram of ICG VA provided valuable information. ICG-VA identified the feeding arteries, the draining veins, and nidus in all 3 AVM cases, which was confirmed by an immediate analysis of fluorescence intensity.

CONCLUSIONS

ICG-VA provides high resolution images allowing real-time assessment of the blood flow in surgical field. The intensity analysis function, in addition, is a useful adjunct to improve the accuracy of the clipping and decrease the complication rates in cerebral aneurysm cases. In cerebral AVM cases, with the help of color map and intensity diagram function, the superficial feeders, drainers, and nidus can be identified easily.

Identification of nitrogen-fixing Paenibacillus from different plant rhizospheres and a novel nifH gene detected in the P. stellifer

A total of 534 isolates were selectively obtained from different plant rhizospheres based on their growth on nitrogen-free medium and their resistance to 80 degrees C for 15 min. Of the 534 isolates, 23 isolates had nifH gene and exhibited nitrogenase activities. Based on 16S rDNA sequence, G + C content assay and DNA-DNA hybridization, by the 23 isolates, which were divided into four monophyletic clusters, all belonged to the Paenibacillus genus. NifH gene deduced amino acid alignment analysis revealed that cluster I, including 15 isolates, showed the highest NifH identity with Paenibacillus genus; while cluster II identified as P stellifer by DNA-DNA hybridization was consistent with four uncultured bacterial clones. This study suggested that the nitrogen-fixing Paenibacillus were distributed in various ecosystems and prevalent in different plant rhizospheres. It was the first demonstration that nitrogen fixation existed in P. jamilae and P. stellifer. In eight isolates identified as P. stellfer species, a novel nifH gene was detected in Paenibacillus.

Identification and Pathogenicity of Chrysoporthe cubensis on Eucalyptus and Syzygium spp. in South China

The genus Chrysoporthe includes important pathogens of plantation-grown Eucalyptus spp. and has been reported from several tree genera in the order Myrtales in tropical and subtropical areas of the world. During disease surveys in South China, fruiting structures typical of Chrysoporthe spp. were observed on cankers on Eucalyptus spp. and Syzygium cumini trees. The aim of this study was to confirm the identity of the Chrysoporthe cubensis infecting the Eucalyptus spp. and S. cumini and to test the pathogenicity of the fungus. Following glasshouse trials to select virulent isolates, field inoculations were undertaken to screen different commercial Eucalyptus genotypes for their susceptibility to the fungus. Isolates were characterized based on their morphology and DNA sequence data for the β-tubulin and internal transcribed spacer regions of the ribosomal DNA. Results showed that the putative pathogen represented the Asian form of C. cubensis, which occurred on numerous different Eucalyptus spp. and hybrid clones as well as S. cumini. Field inoculations showed that all six of the Eucalyptus genotypes tested are susceptible to infection by C. cubensis. Significant differences were observed between them, providing prospects to select disease-tolerant planting stock in the future.

MicroRNA-320 expression in myocardial microvascular endothelial cells and its relationship with insulin-like growth factor-1 in type 2 diabetic rats

1. The aim of the present study was to determine the role of myocardial microvascular endothelial cells (MMVEC) in impaired angiogenesis of type 2 diabetic Goto-Kakizaki (GK) rats. 2. A microRNA (miRNA) microarray was used to assess miRNA expression in MMVEC from GK and Wistar rats. Upregulation of miRNA-320 was observed in MMVEC from GK rats using real-time reverse transcription-polymerase chain reaction (RT-PCR). 3. So far, nine miRNAs have been reported to target angiogenic factors and/or receptors, including kinase insert domain containing receptor (Flk-1), insulin-like growth factor 1 (IGF-1) and insulin-like growth factor 1 receptor (IGF-1R). The predicted genes targeted by miR-320 include Flk-1, IGF-1 and IGF-1R. Western blot analysis and RT-PCR were used to analyse the protein and mRNA expression, respectively, of the putative genes IGF-1 and IGF-1R. The expression of IGF-1 and IGF-1R proteins decreased significantly in diabetic MMVEC. However, the expression of IGF-1 mRNA increased rather than decreased. The mRNA expression of IGF-1R did not differ significantly between diabetic and control MMVEC. 4. Transfection of an miR-320 inhibitor into MMVEC from GK rats confirmed that miR-320 impaired angiogenesis. The proliferation and migration of diabetic MMVEC improved after transfection of the miR-320 inhibitor. In addition, the miR-320 inhibitor significantly increased the expression of IGF-1 protein, but had no effect on the expression of IGF-1R. 5. Eleven miRNAs were upregulated in MMVEC from GK rats compared with those in Wistar rats: let-7e, miR-129, miR-291-5p, miR-320, miR-327, mir-333, miR-363-5p, miR-370, miR-494, miR-503 and miR-664. 6. The results indicate that upregulation of miR-320 in MMVEC from GK rats may be responsible for the inconsistency between the expression of IGF-1 protein and mRNA and therefore related to impaired angiogenesis in diabetes. Transfection of an miR-320 inhibitor may be a therapeutic approach for the treatment of impaired angiogenesis in diabetes.

Adult Pseudomonas aeruginosa meningitis: high incidence of underlying medical and/or postneurosurgical conditions and high mortality rate

We analyzed the clinical and laboratory characteristics, therapeutic outcome and prognostic factors of 25 cases of cerebrospinal fluid (CSF) culture-proven Pseudomonas aeruginosa adult bacterial meningitis (ABM). Twelve P. aeruginosa strains, isolated from clinical CSF specimens, were tested for antibiotic susceptibility. The 25 cases included 17 men and 8 women, aged 17 to 86 years (median=51). Of the 25 cases of P. aeruginosa ABM, 18 were the result of postneurosurgical infection and the other 7 were spontaneous infections. The latter 7 cases had serious underlying medical conditions. The antibiotic susceptibility rates of the 12 strains were as follows: ceftriaxone 16.7% (2/12), ceftazidime 91.7% (11/12), cefepime 83.3% (10/12), imipenem 83.3% (10/12), meropenem 83.3% (10/12) and ciprofloxacin 66.7% (8/12). The therapeutic results showed an overall mortality rate of 40% (10/25). The emergence of third-generation cephalosporin-resistant P. aeruginosa strains cultured from clinical CSF specimens in recent years has resulted in a therapeutic challenge in the treatment of ABM.

Expression of fascin in oral and oropharyngeal squamous cell carcinomas has prognostic significance - a tissue microarray study of 129 cases

AIMS

To elucidate the role of fascin in oral and oropharyngeal squamous cell carcinoma (OSCC) by correlation with clinical parameters.

METHODS AND RESULTS

Paraffin sections using tissue microarrays of 129 patients with OSCC were investigated immunohistochemically. Fascin protein was overexpressed in OSCC cells compared with their non-neoplastic epithelial counterparts. For evaluating the intensity of fascin, 39 (30.2%) were classified as weakly immunoreactive, 76 (58.9%) as moderate reactive and 14 (10.9%) as intensely reactive. For evaluating the distribution of fascin, 64 (49.6%) were classified as < 55% and 65 (50.4%) were classified as >/= 55%. Fascin protein expression was correlated with size or extent of the tumour (P < 0.001), positive lymph node metastasis (P < 0.001), distant metastasis (P = 0.014) and clinical staging (P < 0.001). The immunoreactivity scores of fascin in OSCC were variable but showed significant correlation with histological grade, clinical TNM system and stage.

CONCLUSION

Expression of fascin protein may play an important role in progression of OSCC. Overexpression of fascin contributes to a more aggressive clinical course and suggests the potential of fascin as a new molecular target for therapeutic intervention.

Specific caspase interactions and amplification are involved in selective neuronal vulnerability in Huntington's disease

Huntington's disease (HD) is an autosomal dominant progressive neurodegenerative disorder resulting in selective neuronal loss and dysfunction in the striatum and cortex. The molecular pathways leading to the selectivity of neuronal cell death in HD are poorly understood. Proteolytic processing of full-length mutant huntingtin (Htt) and subsequent events may play an important role in the selective neuronal cell death found in this disease. Despite the identification of Htt as a substrate for caspases, it is not known which caspase(s) cleaves Htt in vivo or whether regional expression of caspases contribute to selective neuronal cells loss. Here, we evaluate whether specific caspases are involved in cell death induced by mutant Htt and if this correlates with our recent finding that Htt is cleaved in vivo at the caspase consensus site 552. We find that caspase-2 cleaves Htt selectively at amino acid 552. Further, Htt recruits caspase-2 into an apoptosome-like complex. Binding of caspase-2 to Htt is polyglutamine repeat-length dependent, and therefore may serve as a critical initiation step in HD cell death. This hypothesis is supported by the requirement of caspase-2 for the death of mouse primary striatal cells derived from HD transgenic mice expressing full-length Htt (YAC72). Expression of catalytically inactive (dominant-negative) forms of caspase-2, caspase-7, and to some extent caspase-6, reduced the cell death of YAC72 primary striatal cells, while the catalytically inactive forms of caspase-3, -8, and -9 did not. Histological analysis of post-mortem human brain tissue and YAC72 mice revealed activation of caspases and enhanced caspase-2 immunoreactivity in medium spiny neurons of the striatum and the cortical projection neurons when compared to controls. Further, upregulation of caspase-2 correlates directly with decreased levels of brain-derived neurotrophic factor in the cortex and striatum of 3-month YAC72 transgenic mice and therefore suggests that these changes are early events in HD pathogenesis. These data support the involvement of caspase-2 in the selective neuronal cell death associated with HD in the striatum and cortex.

Effect of 5-methoxypsoralen (5-MOP) on cell apoptosis and cell cycle in human hepatocellular carcinoma cell line

The chemopreventive role of 5-methoxypsoralen (5-MOP) in the human hepatocellular carcinoma (HCC) cell line was investigated by studying the regulation of proliferation and apoptosis in HCC (J5) cells. Morphological analysis, cell viability assay, DNA analysis and cell-cycle analysis suggest that there are at least three modes of the suppressive effects shown by 5-MOP: (a) kills J5 cells directly; (b) induces apoptosis by arresting J5 cells at the G2/M phase in the cell cycle; (c) induces apoptosis through an independent pathway with cell-cycle arrest at 24-72 h of exposure. Further immunoblot analysis demonstrated that inhibition of cyclin B1 by 5-MOP may play an important role in G2/M arrest of J5 cells and provides an additional way to prevent cells from entering the M phase and undergoing apoptosis. 5-MOP therefore appears to exert its anticarcinogenic properties by cytotoxic effect, inducing apoptosis and inhibiting proliferation in the human hepatocellular carcinoma cell line.

A ligand-receptor pair that triggers a non-apoptotic form of programmed cell death

Several receptors that mediate apoptosis have been identified, such as Fas and tumor necrosis factor receptor I. Studies of the signal transduction pathways utilized by these receptors have played an important role in the understanding of apoptosis. Here we report the first ligand-receptor pair-the neuropeptide substance P and its receptor, neurokinin-1 receptor (NK(1)R)-that mediates an alternative, non-apoptotic form of programmed cell death. This pair is widely distributed in the central and peripheral nervous systems, and has been implicated in pain mediation and depression, among other effects. Here we demonstrate that substance P induces a non-apoptotic form of programmed cell death in hippocampal, striatal, and cortical neurons. This cell death requires gene expression, displays a non-apoptotic morphology, and is independent of caspase activation. The same form of cell death is induced by substance P in NK(1)R-transfected human embryonic kidney cells. These results argue that NK(1)R activates a death pathway different than apoptosis, and provide a signal transduction system by which to study an alternative, non-apoptotic cell death program.

Treatment of refractory acute leukemia with timed sequential chemotherapy using topotecan followed by etoposide + mitoxantrone (T-EM) and correlation with topoisomerase II levels

A phase I/II clinical study evaluated 17 patients with refractory/recurrent acute leukemia treated with 1.5 mg/m2/day topotecan on days 1-3 followed by etoposide (100 mg/m2/day)+mitoxantrone (10 mg/m2/day) on days 4, 5 and 9, 10. Timed sequential chemotherapy using the topoisomerase I-inhibitor topotecan before the topoisomerase II-inhibitors, etoposide+mitoxantrone (T-EM) treatment is proposed to induce topoisomerase II protein levels and potentiate the cytotoxic activity of the topoisomerase II-directed drugs. Fourteen patients had refractory and three had recurrent acute leukemia. The majority of patients were heavily pre-treated with greater than three re-induction chemotherapy regimens. Ten patients responded to T-EM treatment (59%). Four of seventeen (24%) had a complete remission and one had a partial remission. Four additional patients (24%) who scored complete leukemia clearance had no evidence of disease with complete white and red blood cell recovery but with platelet counts less than 100,000. The lack of platelet recovery in one patient having a partial response was scored as a partial leukemia clearance. The toxicity profile included major non-hematological toxicity including grade 3 mucositis (29%) and neutropenic fever (65%). Paired measurements of intracellular levels of topoisomerase II isoforms alpha and beta in leukemia blast cells (bone marrow) collected before (day 0) and after topotecan treatment (day 4) showed that a relative increase of topoisomerase IIalpha (Topo IIalpha) > or = 40% strongly correlated with response after T-EM treatment. Increased Topo IIalpha levels also corresponded to increased DNA fragmentation. Two patients who had an increase of Topo IIalpha of 20-25% had either a PR or PLC while patients with a < 10% increase showed no response to T-EM treatment. We conclude that timed sequential chemotherapy using topotecan followed by etoposide+mitoxantrone is an effective regimen for patients with refractory acute leukemia, and demonstrate Topo IIalpha protein level increases after topotecan treatment.

[Cloning and functional analysis of glnB from Azospirillum brasilense Yu62]

The glnB gene of A. brasilense Yu62 was determined in a 3.7 kb EcoRI + PstI fragment. The glnA is located downstream of glnB and an ORF for hypothetical protein is on upstream of glnB. The deduced amino acid sequence of PII encoded by glnB is 71%, 77%, 79% and 69% identical to that of K. pneumoniae, Bradyrhizobium japonicum, Rhizobium leguninosarum and E. coli, respectively. A Km-casette was inserted into BglII site of glnB coding region and GlnB- mutant was obtained by homologous recombination. The GlnB- mutant has lost the nitrogenase activity, i.e.: Nif-. For the functional confirmation of glnB gene, a complementary test was carried out and it was shown that C-glnB(glnB::Km/glnB) can restore the nitrogenase activity. When the recombinant plasmid pVK-II which containined the coding region of glnB was introduced into A. brasilense Yu62 and A. brasilense Yu62 DraT-, respectively, the Yu62-II (containing pVK-II) and draT-II(containing pVK-II) showed higher nitrogenase activity than wild type. These results confirmed that glnB plays an important role in the regulation of nitrogen in A. brasilense.

The spatial distribution of macular pigment in humans

PURPOSE

To estimate the distributions in width as well as in density of macular pigment (MP) in humans at different ages, imaging fundus reflectometry was employed as a tool to reach our aim.

METHODS

Imaging fundus reflectometry was used to measure the macular pigment distribution in human eyes with a modified fundus camera to which a cooled CCD camera was attached. The fundus images were taken at 460 nm and 560 nm after the retina was light-adapted to completely bleach rhodopsin. The density of macular pigment was estimated using a model described in the text. The variation in density with retinal eccentricity was fit to Gaussian distribution. The width of MP in retinal eccentricity was estimated by 95% covering area of the distribution profile. A total of 54 normal people served as subjects. They were divided into three groups with ages of 24.8 +/- 2.6 years (N = 24), 40.2 +/- 8.3 years (N = 13) and 67.5 +/- 7.1 years (N = 17) respectively. Statistical t-tests were employed to evaluate the differences in MP density, the half width of MP distributed (HWMPD) in retina with respect to age between the groups. Linear regression was also applied to reveal the relationships of HWMPD distribution with respect to age.

RESULTS

The results indicate that the average MP densities are 0.23 +/- 0.08, 0.22 +/- 0.06 and 0.23 +/- 0.06 density unit (DU) for the young to old age groups. The average MP density is 0.23 +/- 0.07. No statistical significant difference is found in the peak MP density between the groups (all p > 0.05). This result pretty agrees with the data that obtained from others by using optical methods. For the young to old age groups, the average estimated HWMPD are 2.6 degrees +/- 0.5 degrees, 3.1 degrees +/- 0.5 degrees and 4.1 degrees +/- 0.6 degrees respectively. The differences between loci of HWMPD in the three groups are statistically significant with p = 0.0059, p < 0.0001 and p = 0.0001 for young vs. mid-age, young vs. old and mid-age vs. old respectively. Linear regressions for the HWMPD vs. age (r = 0.734, p < 0.001) implies that the macular pigment can gradually accumulate and spread out to the periphery of retina through our life span with an increase rate of approximately 0.03 degrees /year.

CONCLUSIONS

The accumulation of MP is reflected by the broader area in the macula lutea due to age, but no significant change is observed in peak density. The cause of the extension in the macular area with respect to age is unknown.

The involvement of glutamate in recall of the conditioned NK cell response

The molecular mechanisms responsible for the conditioned enhancement of natural killer (NK) cell activity were investigated. The primary goal of the study was to examine the roles of glutamate and gamma-aminobutyric acid (GABA) in recall of the conditioned NK cell response. Both neurochemical blocking assay and high performance liquid chromatography (HPLC) technique were used in the study. Results from the neurochemical blocking assay demonstrated that glutamate but not GABA was required in recall of the conditioned NK cell response. NMDA but not the kainate/AMPA receptors, are believed to be involved. The levels of glutamate that were released and/or taken up also appeared to be critical in that interruption of glutamate release and/or uptake blocked the conditioned NK cell response. Results from the HPLC analysis, however, did not show any significant difference in the glutamate content between the conditioned and control brains.

Induction of Tie-1 and Tie-2 receptor protein expression after cerebral ischemia-reperfusion

Tie-1 and Tie-2 are receptor tyrosine kinases (RTKs) that are exclusively expressed in endothelial cells and play important roles in endothelial cell biology. The authors have reported previously the temporal profiles of Tie-1 and Tie-2 mRNA expression after focal cerebral ischemia-reperfusion. In the current study, the localization of Tie-1/Tie-2 mRNA and proteins were further investigated in the same focal ischemia model. In situ hybridization showed that, after 60-minute ischemia and 72-hour reperfusion, both Tie-1 and Tie-2 mRNA appeared as capillary-like structures in the ischemic middle cerebral artery (MCA) cortex. Western blot analysis showed a biphasic expression of Tie-1 protein in the same region. The first peak, spanning the ischemic and early reperfusion period. was of low intensity and short-lived. The second peak was of greater intensity and spanning the period from 72 to 168 hours after reperfusion. Similarly, Tie-2 expression at the protein level also exhibited a biphasic pattern. Immunohistochemical studies, after 72 hours of reperfusion, showed that although Tie-1 and Tie-2 were detected within the ischemic cortex, they actually were expressed in different populations of endothelial cells in different regions. In agreement with the in situ hybridization study, Tie-1 immunoreactivity appeared as capillary-like structures in cortical layers 2 to 4. Similar capillary-like appearance of Tie-2 immunoreactivity was noted in the outer cortical layers. In addition, Tie-2 immunoreactivity also was observed in cortical layer 6b, where de novo large vessel formation was noted. Cellular colocalization experiments revealed that Tie-2 is expressed in proximity to its antagonist, Angpo-2, as well as basic fibroblast growth factor (bFGF) and vascular endothelial growth factor (VEGF) in cortical layer 1, where active vessel remodeling was noted. Interestingly, bFGF only partially colocalized with VEGF, suggesting differential roles for these angiogenic factors during vessel remodeling. Tie-1 protein, to a lesser degree, also colocalized with Angpo-2, bFGF, and VEGF in cortical layer 1. Magnetic resonance imaging (MRI) showed increased regional cerebral blood flow (CBF) corresponding to the expression of these angiogenesis gene products. Together, these findings suggest that the evolving expression of angiogenesis genes underlie the robust vascular remodeling after ischemia and reperfusion.

Potentiation of antitumor activity of irinotecan by chemically modified oligonucleotides

Co-administration of synthetic chemically modified oligonucleotides with irinotecan, a selective topoisomerase I inhibitor, provided a significant enhancement in the antitumor activity of irinotecan. The enhancement of antitumor activity of irinotecan with co-administration of chemically modified oligonucleotides was observed in several tumor models--pancreatic cancer (Panc-1), colon cancer (HCT-116) and melanoma (A375). Inhibition of tumor growth in all three models required the co-administration of irinotecan and chemically modified oligonucleotides, but was independent of the nucleotide sequence of the oligonucleotides. The potentiation of antitumor activity was dependent on the dose of irinotecan and chemically modified oligonucleotides administered. The enhancement of antitumor activity of irinotecan was also observed by co-administration of a phosphorothioate oligonucleotide, however, to a lesser extent than did chemically modified oligonucleotides, suggesting that metabolic stability of the oligonucleotide contributes to the enhancement of antitumor activity seen with irinotecan. The co-administration of dextran sulfate sodium with irinotecan showed insignificant potentiation of antitumor activity of irinotecan, suggesting that the enhancement of antitumor activity of irinotecan observed was not a result of polyanionic characteristic of oligonucleotides. Co-administration of irinotecan and chemically modified oligonucleotides did not result in increased toxicity in the tumor models studied. Potentiation of antitumor activity of irinotecan observed with co-administration of oligonucleotides suggests that the oligonucleotides affect the pharmacokinetics and/or metabolism of irinotecan. The use of chemically modified oligonucleotides together with irinotecan may increase the therapeutic index of irinotecan in cancer patients and continued development of such agents should be considered.

Determination of aqueous chlorothalonil with solid-phase microextraction and gas chromatography

Solid-phase microextraction coupled with GC-electron-capture detection was examined to analyze aqueous chlorothalonil residuals. The optimal conditions for chlorothalonil pre-concentration such as fiber polarity, temperature, salt addition, absorption time, as well as the interference were investigated in detail. In addition, the thermal desorption conditions in the injector were also systematically optimized. Experimental results indicated that an extraction with a 100-microm polydimethylsiloxane fiber for 40 min under conditions of 1250 rpm stirring rate, room temperature, and adding high concentration salt offered an optimal result. The thermal desorption of chlorothalonil at 240 degrees C for 3 min (including fiber regeneration) offered the best sensitive detection. A standard addition method for calibration was recommended to reduce the deviation from matrix interference. The proposed method provided a simple and rapid analytical procedure for chlorothalonil in water bodies with detection limits of 2.86 microg/l for distilled water, 3.06 microg/l for ground water, 4.77 microg/l for tap water, and 9.23 microg/l for farm water. The relative standard deviations were all below 3.0% (n=6) besides the farm water being below 9.2%. The calibration graph in the range of 5 to 200 microg/l is linear with very good correlation coefficient (r=0.999), and r=0.983 for farm water. Application was illustrated by the analysis of water samples collected from tap water, ground water and farm water in the southern Taichung area.

Induction of angiogenesis related genes in the contralateral cortex with a rat three-vessel occlusion model

The bFGF/FGFR, VEGF/VEGFR and Angiopoietin/Tie receptor system are crucial for angiogenesis and vascular remodeling. With a rat focal cerebral ischemia model, we previously reported dramatic changes in the vascular density and angiogenesis related genes in the ipsilateral cortex after 60 minutes severe ischemia. While only a small increase in the capillary density was noted in the contralateral cortex with very mild ischemia. In the present study we further reported that only Tie-1 and VEGFR-2 mRNA were significantly changed in the contralateral cortex with a p value of 0.0001 and 0.0168, respectively, and the degree of changes were very small. Interestingly, in contrast to a huge increase in the ipsilateral cortex, Tie-1 mRNA was slowly decreased after the onset of ischemia and stayed below the basal level throughout the remaining periods studied. The mechanism and significance for this decrease is not presently clear. In contrast to the ipsilateral cortex, the Angpo-1/Angpo-2 mRNA ratio was also slightly dropped below the basal level in the contralateral side in most of the ischemia-reperfusion periods studied, which is in line with the notion that small decrease in Angpo-1/Angpo-2 mRNA ratio implied small vascular remodeling activity. It is very likely that increase in this Angpo-1/Angpo-2 ratio is crucial for remodeling into large vessels and increase in Tie-1 may be crucial for capillary density increasing. Nevertheless, the detailed mechanisms and significance of differential expression of these genes and relationship to vascular remodeling remain to be characterized.