Granulocyte colony stimulating factor decreases brain amyloid burden and reverses cognitive impairment in Alzheimer's mice

Granulocyte colony stimulating factor (G-CSF) is a multi-modal hematopoietic growth factor, which also has profound effects on the diseased CNS. G-CSF has been shown to enhance recovery from neurologic deficits in rodent models of ischemia. G-CSF appears to facilitate neuroplastic changes by both mobilization of bone marrow-derived cells and by its direct actions on CNS cells. The overall objective of the study was to determine if G-CSF administration in a mouse model of Alzheimer's disease (AD) (Tg APP/PS1) would impact hippocampal-dependent learning by modifying the underlying disease pathology. A course of s.c. administration of G-CSF for a period of less than three weeks significantly improved cognitive performance, decreased beta-amyloid deposition in hippocampus and entorhinal cortex and augmented total microglial activity. Additionally, G-CSF reduced systemic inflammation indicated by suppression of the production or activity of major pro-inflammatory cytokines in plasma. Improved cognition in AD mice was associated with increased synaptophysin immunostaining in hippocampal CA1 and CA3 regions and augmented neurogenesis, evidenced by increased numbers of calretinin-expressing cells in dentate gyrus. Given that G-CSF is already utilized clinically to safely stimulate hematopoietic stem cell production, these basic research findings will be readily translated into clinical trials to reverse or forestall the progression of dementia in AD. The primary objective of the present study was to determine whether a short course of G-CSF administration would have an impact on the pathological hallmark of AD, the age-dependent accumulation of A beta deposits, in a transgenic mouse model of AD (APP+ PS1; Tg). A second objective was to determine whether such treatment would impact cognitive performance in a hippocampal-dependent memory paradigm. To explain the G-CSF triggered amyloid reduction and associated reversal of cognitive impairment, several mechanisms of action were explored. (1) G-CSF was hypothesized to increase activation of resident microglia and to increase mobilization of marrow-derived microglia. The effect of G-CSF on microglial activation was examined by quantitative measurements of total microglial burden. To determine if G-CSF increased trafficking of marrow-derived microglia into brain, bone marrow-derived green fluorescent protein-expressing (GFP+) microglia were visualized in the brains of chimeric AD mice. (2) To assess the role of immune-modulation in mediating G-CSF effects, a panel of cytokines was measured in both plasma and brain. (3) To test the hypothesis that reduction of A beta deposits can affect synaptic area, quantitative measurement of synaptophysin immunoreactivity in hippocampal CA1 and CA3 sectors was undertaken. (4) To learn whether enhanced hippocampal neurogenesis was induced by G-CSF treatment, numbers of calretinin-expressing cells were determined in dentate gyrus.

Novel mutations of cathepsin C gene in two Chinese patients with Papillon-Lefèvre syndrome

Papillon-Lefèvre syndrome (PLS) is an inherited human disease characterized by early-onset periodontitis and palmoplantar hyperkeratosis. Mutations of the lysosomal protease cathepsin C (CTSC) gene have been shown to be the genetic cause of Papillon-Lefèvre syndrome. There are several case reports in China, while there has been no study on the genetic analysis of PLS. We studied two Chinese patients carrying Papillon-Lefèvre syndrome and showing premature tooth loss and palmoplantar hyperkeratosis. Mutation screening and sequence analysis of the CTSC gene revealed a compound heterozygous mutation (c.415 G>A and c.778 T>C) in one patient, and two novel compound heterozygous mutations (c.851G>A and c.112delCCTG) in the other patient. Our novel discovery indicates that the phenotypes observed in these two patients are due to the CTSC gene mutation.

A giant outburst two years before the core-collapse of a massive star

The death of massive stars produces a variety of supernovae, which are linked to the structure of the exploding stars. The detection of several precursor stars of type II supernovae has been reported (see, for example, ref. 3), but we do not yet have direct information on the progenitors of the hydrogen-deficient type Ib and Ic supernovae. Here we report that the peculiar type Ib supernova SN 2006jc is spatially coincident with a bright optical transient that occurred in 2004. Spectroscopic and photometric monitoring of the supernova leads us to suggest that the progenitor was a carbon-oxygen Wolf-Rayet star embedded within a helium-rich circumstellar medium. There are different possible explanations for this pre-explosion transient. It appears similar to the giant outbursts of luminous blue variable stars (LBVs) of 60-100 solar masses, but the progenitor of SN 2006jc was helium- and hydrogen-deficient (unlike LBVs). An LBV-like outburst of a Wolf-Rayet star could be invoked, but this would be the first observational evidence of such a phenomenon. Alternatively, a massive binary system composed of an LBV that erupted in 2004, and a Wolf-Rayet star exploding as SN 2006jc, could explain the observations.

Modulation of cortical activity as a result of task-specific practice

This report aims to examine the role of task-specific practice in the modification of finger force enslaving and to provide empirical evidence for specific EEG frequency bands accompanying such practice may be an end-effectors dependent phenomenon. Nine handed naïve subjects without any training in music participated in a pre- and post-practice sessions separated by 12 practice sessions. Subjects performed a series of isometric force production tasks at 10% and 50% maximum voluntary contraction (MVC) with two rates of force development separately by index and ring fingers. Task-specific practice aimed at suppressing the contribution of neighboring fingers was achieved via visual feedback of force traces. Behavioral data (accuracy of force production and amount of force enslaving) and EEG data in frequency domain obtained via Morlet Wavelet transforms were analyzed. The major behavioral finding is that task-specific practice significantly enhanced the accuracy of force production and individuated control of the "most enslaved" ring finger (P<0.01), but not the index finger. The major novel EEG findings are: (a) modulation of EEG activity within alpha band (8-12 Hz) in the central area of the brain as a function of practice was similar for both fingers and (b) after practice, modulation of EEG activity within gamma (30-50 Hz) band was end-effectors specific. Both behavioral and EEG patterns suggest an effect of task-specific practice on the reduction of force enslaving and that modulation of practice-related plasticity in the human cortex is end-effectors dependent phenomena.

Plasminogen Activator Inhibitor-1 Promoter Polymorphism is Not Associated With the Aggressiveness of Disease in Prostate Cancer

AIMS

PAI-1 (plasminogen activator inhibitors-1) regulates plasminogen activation, and is related to tumour development. This study aims to test whether the promoter polymorphism in the PAI-1 gene is related to the aggressiveness of disease in prostate cancer.

MATERIALS AND METHODS

In the present study, Taqman SNP genotyping assay was used to detect PAI-1 4G/5G polymorphism in DNA from paraffin-embedded tissues of 98 Caucasian patients with prostate cancer.

RESULTS

The distribution of the genotypes is in Hardy-Weinberg equilibrium. The genotype had no statistically significant relationship with other prognostic factors. Similar risks for recurrence were seen in individuals with the 4G/4G and 4G/5G genotypes compared to those with 5G/5G genotype (odds ratio [OR] 2.65, 95% CI: 0.41-16.94, P = 0.30; OR = 2.19, 95% CI: 0.38-12.49, P = 0.38).

CONCLUSION

We concluded that PAI-1 promoter polymorphism is not associated with the aggressiveness of disease in prostate cancer.

Retrospective analysis of varicella zoster virus (VZV) copy DNA numbers in plasma of immunocompetent patients with herpes zoster, of immunocompromised patients with disseminated VZV disease, and of asymptomatic solid organ transplant recipients

BACKGROUND

Varicella zoster virus (VZV) causes significant morbidity and mortality in immunocompromised patients. Subclinical reactivation has been described in solid organ recipients and has been associated with graft versus host disease in bone marrow transplantation. Newer studies assessing the prevalence and impact of subclinical VZV reactivation in solid organ transplant (SOT) recipients are lacking.

METHODS AND RESULTS

In a first step we developed a highly sensitive quantitative polymerase chain reaction (qPCR) assay for VZV DNA with a detection limit of < or = 20 copies/mL. Using this assay, we retrospectively analyzed plasma samples of different patient groups for VZV DNA. VZV DNA was found in 10/10 plasma samples of immunocompetent patients with herpes zoster (VZV copy numbers/mL: mean+/-SEM 1710+/-1018), in 1/1 sample of a human immunodeficiency virus-infected patient with primary VZV disease (15,192 copies/mL) and in 4/4 plasma samples of immunocompromised patients with visceral VZV disease (mean of first value 214,214+/-178,572). All 108 plasma samples of asymptomatic SOT recipients off any antiviral therapy, randomly sampled over 1 year, were negative for VZV DNA.

CONCLUSION

Our qPCR assay proved to be highly sensitive (100%) in symptomatic VZV disease. We did not detect subclinical reactivation in asymptomatic SOT recipients during the first post-transplant year. Thus, subclinical VZV reactivation is either a rare event or does not exist. These data need to be confirmed in larger prospective trials.

Nocturnal sleep apnea/hypopnea is associated with lower memory performance in APOE ε4 carriers

The authors investigated the relationship between obstructive sleep apnea/hypopnea (OSAH) and cognition in 36 older adults, 18 APOE ε4 carriers, and 18 non-carriers. Greater numbers of respiratory events negatively impacted memory function in ε4 carriers only. This is the first study to provide preliminary evidence for a negative interaction of APOE ε4 and OSAH on memory in older adults, which may have important implications for treating cognitive decline and delaying dementia onset.

[Arthralgia, eosinophilia, proteinuria and diuretics-resistant leg edemas]

We report the case of a patient with eosinophilic fasciitis, a rare disease related to systemic sclerodermia and other fibrosing disorders. An involvement of the kidneys--like in this patient with proteinuria and hypoproteinemia--has been described in the literature but is very rare. We discuss diagnostic procedures and novel therapeutic options as combination therapies with steroids, methotrexate and ciclosporine A.

Human single chain Fv antibodies and a complementarity determining region-derived peptide binding to amyloid-beta 1–42

A library of phage-displayed human single-chain Fv (scFv) antibodies was selected against the human amyloid-beta peptide (Abeta42). Two new anti-Abeta42 phage-displayed scFvs antibodies were obtained, and the sequences of their V(H) and Vkappa genes were analyzed. A synthetic peptide based on the sequence of Ig heavy chain (V(H)) complementarity-determining region (HCDR3) of the clone with the highest recognition signal was generated and determined to bind to Abeta42 in ELISA. Furthermore, we showed for the first time that an HCDR3-based peptide had neuroprotective potential against Abeta42 neurotoxicity in rat cultured hippocampal neurons. Our results suggest that not only scFvs recognizing Abeta42 but also synthetic peptides based on the V(H) CDR3 sequences of these antibodies may be novel potential candidates for small molecule-based Alzheimer's disease (AD) therapy.

Molecular characterization of insulin-like peptide genes and their expression in the African malaria mosquito, Anopheles gambiae

Of the seven genes encoding insulin-like peptides (ILPs) in the mosquito, Anopheles gambiae, four are arrayed proximally as duplicate pairs on chromosome three. Amino acid substitutions encoded in the duplicate genes occur in the C peptide and not the B and A peptides. Except for one duplicated gene, sequence-specific transcripts for all other AgamILPs were obtained from female mosquitoes. Transcript expression of each AgamILP was determined by RT-PCR in the head, thorax, and abdomen of all life stages and both sexes of this mosquito. Two AgamILPs were ubiquitously expressed, suggesting a growth factor function, whereas the other AgamILPs were expressed primarily in heads, as confirmed by the immunostaining of ILPs in the neurosecretory cells of female brains, thus indicating a hormonal function.

Amyloid-beta peptide-specific single chain Fv antibodies isolated from an immune phage display library

A single-chain fragment variable (scFv) antibody library displayed on phage was constructed using spleen cells from mice immunized with human amyloid-beta peptide (Abeta42). This first anti-Abeta42 scFv immune antibody library was selected against human Abeta42. A number of positive clones were obtained, and sequences of VH and Vkappa genes were analyzed using ExPASy and BLAST computer tools. This analysis revealed that only two unique clones with identical VH and Vkappa complementarity determining region (CDR) (except HCDR2) and identical germline genes were selected, indicating that oligoclonal immune response was occurring in Abeta42-immunized mice. Abeta42-specific scFv antibodies selected from this first immune anti-Abeta42 phage antibody library may be an important tool for the development of therapeutic molecules for Alzheimer's disease (AD).

Association of vitamin D receptor gene polymorphism with periodontal diseases in Japanese and Chinese

We examined whether polymorphisms in the vitamin D receptor (VDR) gene are associated with the incidence of adult periodontitis (AP) and early-onset periodontitis (EOP) in case-controlled studies of Japanese and Chinese subjects. Restriction fragment length polymorphisms in the VDR gene detected by digestion with Taq I were found to be significantly associated with the occurrence of AP or EOP, suggesting that the VDR genotype a risk factor for periodontitis.

[Intermittent-pulse treatment of onychomycosis with orally administered itraconazole]

Fifty-four patients received an intermittent regimen of itraconazole (26 of them were finger onychomycosis and 28 toe onychomycosis) and were followed-up for nine months. The result showed that the clinical cure rate of fingernails was 88.5% and the mycologic cure rate was 96.4%, while the clinical cure rate of toes was 82.1% and the mycologic cure rate was 96.4%. Few adverse events were observed by 7.4%, just like nausea, gastric discomfort etc. It suggests that the pulse administration system is highly effective and has a few side-effects.

A four-day study to evaluate the anti-plaque efficacy of an experimental triclosan-containing dentifrice

Four-day, non-brushing studies have been used successfully to demonstrate the anti-plaque efficacy of triclosan-containing dentifrices. The treatment effects observed are variable, likely due to differences in formulation, study design and measurement techniques. This randomized, double-blind crossover study was conducted to evaluate the anti-plaque efficacy of an experimental, multiple-benefit, triclosan-containing dentifrice versus two currently marketed sodium fluoride dentifrices in a four-day, lingual-brushing model on subjects in Beijing. People's Republic of China. Subjects brushed the lingual surfaces for 30 seconds, and before expectorating, swished the saliva/dentifrice slurry over the buccal surfaces for an additional 30 seconds. This procedure was repeated. Subjects performed their assigned brushing regimen twice daily for four days under supervision. On Day 5, plaque was measured using the Turesky Modification of the Quigley-Hein Plaque Index. There were highly significant treatment effects in favor of the experimental triclosan-containing dentifrice for whole mouth, buccal and lingual sites when compared to either of the sodium fluoride dentifrices (p < 0.0001).

Pyrogenic cytokines injected into the rat cerebral ventricle induce cyclooxygenase-2 in brain endothelial cells and also upregulate their receptors

Peripheral immunological insults induce interleukin (IL)-1 beta and IL-6 in the brain. To elucidate the mechanism(s) of fever evoked by these brain-derived cytokines, and possible interactions between them, we examined in rats: (i) whether cyclooxygenase-2 is responsible for fever evoked by central injection of these cytokines; (ii) if so, where in the brain cyclooxygenase-2 is induced; (iii) where the receptors for these cytokines are located; and (iv) how the expression of these receptors is influenced by the cytokines. Intracerebroventricular injection of these cytokines evoked fever that was suppressed by a cyclooxygenase-2 inhibitor. Brain endothelium was the site of cyclooxygenase-2 induction by these cytokines. IL-1 receptor (IL-1R) was constitutively expressed in brain endothelium, and its mRNA was further upregulated by either cytokine. IL-6R mRNA was constitutively expressed in the cerebral cortex, and was newly induced in as yet unidentified cells in brain blood vessels by either cytokine. Messenger RNAs for cyclooxygenase-2, IL-1R, and IL-6R were often observed in the same blood vessels. These results suggest that COX-2 induced in brain endothelium is, at least in part, involved in the fever evoked by these cytokines, and that one possible interaction between these two cytokines is mutual upregulation of their receptors in the endothelium or perivascular cells, resulting in augmentation of their actions.

Diagnosing primary and metastatic renal cell carcinoma: the use of the monoclonal antibody 'Renal Cell Carcinoma Marker'

The diagnosis of primary or metastatic renal cell carcinoma (RCC) can be difficult, especially in small biopsies, because of the wide variety of histologic appearances and clinical presentations that RCC can assume. An immunomarker specific for RCC is currently not available. We tested the relevant diagnostic use of the Renal Cell Carcinoma Marker (RCC Ma), a monoclonal antibody, against a normal human proximal tubular brush border antigen. Immunostaining using RCC Ma and the avidin-biotin-peroxidase complex technique was performed on archival tissues from primary and metastatic tumors of renal or nonrenal origin. A total of 122 of 153 primary RCCs (79.7%) were positive [clear cell (84%), papillary (96%), chromophobe (45%), sarcomatoid (25%), and collecting duct (0%)], with > or =10% of tumor cells stained in 93% of cases. None of the 64 primary renal tumors other than RCC, including 15 oncocytomas, was positive. Fifteen of 146 (10.2%) nonrenal primary tumors were positive (5 of 17 breast tumors, 8 of 8 parathyroid adenomas, and 2 of 7 embryonal carcinomas). Forty-two of 63 (67%) metastatic RCCs were positive with > or =10% of cells being stained in 83% of them. Two of 108 (2%) metastases from tumors other than RCCs were positive, both of which were metastatic breast carcinomas; however, only 10% (2 of 19) of metastatic breast carcinomas were positive. RCC Ma is an excellent marker for primary RCC, which should facilitate its diagnosis in a small biopsy. Although RCC Ma remains highly specific (98%) for metastatic RCC, a negative result may not rule out metastatic RCC because of a rather low sensitivity and a focal staining pattern in some of the positive cases. RCC Ma may also facilitate the differential diagnosis between oncocytoma and other types of RCC when they are composed mostly of eosinophilic cells.

[The efficacy of the chlorhexidine chip following scaling and root planing (SRP) and compared to SRP alone]

OBJECTIVE

To evaluate the clinical efficacy and safety of the adjunctive use of Chlorhexidine Chip (CHX; commercial name, Perio Chip) following scaling and root planing (SRP) in periodontitis.

METHODS

One center, blinded, randomized, split-mouth and active control study was designed. Sixty-five adult periodontitis patients were enrolled into the baseline after SRP. Each subject had at least one tooth with pocket depth of 5 mm or more and bleeding on probing (BOP) in each side of the mouth. Then the tooth was selected as a target and its parameters of probing depth (PD), attachment loss (AL), BOP, gingival index (GI), plaque index (PI) and staining index (SI) were recorded. Each side of mouth was randomly assigned to one of two treatments--drug placement after SRP or SRP alone. All the adverse events and parameters were recorded at time of 3-month, 6-month and meanwhile the patients received oral hygiene instruction and scaling. The same was conducted at 6-week, 4.5-month except for recording of parameters and scaling of the target teeth.

RESULTS

Reduction of PD and gain of attachment at 6-month in group of SRP plus CHX (1.32 mm, 0.94 mm) were significantly higher than those in group of SRP alone (0.77 mm, 0.40 mm) (P < 0.001). Forty-four point six percent (44.6%) of patients reflected adverse reactions related to drug placement. Toothaches, the main reactions, were mild to moderate in nature and spontaneously resolved within 2-4 days.

CONCLUSIONS

The chlorhexidine chip is indeed a safe and effective control-delivered drug for topical use when patient in his supportive periodontal therapy.

Duration and specificity of humoral immune responses in mice vaccinated with the Alzheimer's disease-associated beta-amyloid 1-42 peptide

Alzheimer's disease (AD) is a neurodegenerative disorder characterized by overproduction of beta-amyloid (Abeta), which is formed from amyloid precursor protein (APP), with the subsequent pathologic deposition of Abeta in regions of the brain important for memory and cognition. Recently, vaccination of murine models of AD that exhibit Abeta deposition has halted or delayed the usual progression of the pathology of AD. Our group has demonstrated that vaccination of a doubly transgenic mouse model (expressing mutant APP and presenilin-1) with the Abeta 1-42 peptide protects these mice from the memory deficits they would ordinarily develop. This report further characterizes the Abeta 1-42 peptide vaccine in mice. Anti-Abeta response time course analysis indicated that at least three vaccinations (each 100 microg) were necessary to elicit a significant anti-Abeta titer. Subsequent vaccinations resulted in half-maximal antibody titers of at least 10,000, and these titers were maintained for at least 5 months after the final boost. Peptide binding competition studies indicated that the highest humoral responses are generated against the N terminus of the Abeta peptide. Also, measurement of specific murine Ig isotypes in Abeta-vaccinated mice demonstrated a predominant IgG(1) and IgG(2b) response, suggesting a type 2 (Th2) T-helper cell immune response, which drives humoral immunity. Finally, lymphocyte proliferation assay experiments using Abeta peptides and splenocytes from vaccinated mice demonstrated that the vaccine specifically stimulates T-cell epitopes present within the Abeta peptide.

Abnormal DNA-binding of transcription factors in minimal change nephrotic syndrome

The activation of transcription factors such as nuclear factor kappaB (NF-kappaB) and activator protein 1 (AP-1) plays an important role in regulating the expression of target genes, including those for cytokines involved in pathogenesis of minimal change nephrotic syndrome (MCNS). The therapeutic effects of glucocorticoids depend on the glucocorticoid receptor (GR) acting on gene transcription and interacting with certain transcription factors. To explore the role of transcription factors in the pathogenesis of MCNS and the therapeutic effects of glucocorticoids, we examined the DNA-binding abilities of NF-kappaB, AP-1, and GR in peripheral blood mononuclear cells (PBMC) from 6 children with MCNS and 6 healthy controls by electrophoretic mobility shift assay (EMSA). NF-kappaB and AP-1 DNA-binding abilities were significantly increased both at baseline and after stimulation by phorbol 12-myristate 13-acetate (TPA) in PBMC from MCNS patients compared with controls, but declined to normal levels after treatment with dexamethasone (DEX). GR DNA-binding abilities were significantly reduced at baseline and after treatment with TPA, but were enhanced markedly by DEX. There were strong correlations between urinary protein and the baseline DNA binding ability of NF-kappaB or AP-1, or GR. These results suggested that the abnormal activation of NF-kappaB and AP-1 and the reduction of GR DNA-binding abilities may be involved in the pathogenesis of MCNS. Inhibition of NF-kappaB and AP-1 and enhancement of GR DNA-binding abilities by DEX may form the molecular basis of the effects of glucocorticoids in MCNS.

Expression of Streptococcus mutans wall-associated protein A gene in Chinese hamster ovary cells: prospect for a dental caries DNA vaccine

The Streptococcus mutans strain GS-5 wall-associated protein A (Wap-A) is a precursor to the extracellular antigen A (AgA), a recognized candidate dental caries vaccine. The full-length wapA gene (wapA-E) and a C-terminal truncated version (wapA-G) encoding the AgA were cloned into the mammalian expression vector pcDNA 3.1/V5/His-TOPO. The resulting constructs were propagated in the Escherichia coli Top10. To investigate the expression of the S. mutans genes in mammalian cells, the above constructs were used to transfect Chinese hamster ovary (CHO) cells in the presence of the cationic lipid pfx-8. Transient expression of the wapA-E and wapA-G genes was observed at 24 h post-transfection, as shown by Western immunoblot analysis using a rabbit antiserum to S. mutans cell wall. Immunochemical staining of the transfected CHO cells showed expression of WapA mainly in the cells and budding vesicles, whereas AgA was found mainly in the transfected cells and extracellular medium. The expression of S. mutans proteins in CHO cells, in either vesicles or soluble form, suggested an antibody response to the above DNA constructs. Work is under way to test the efficacy of these as DNA vaccines against S. mutans.

[A study on affecting factors on dental care demands by logistic regression model]

OBJECTIVE

To develop probability model for dental visits based on analysis of the factors affecting people's dental services utilization in urban area of Beijing, thus providing some evidence for forecasting further demanded dental care and building the more efficient oral health care delivery system.

METHODS

A cross-sectional survey was conducted amnog 1,517 subjects of all age groups in Beijing selected by stratified, clustering, random sampling. The first model of dental care demand--probability model for dental visits was established with logistic regression.

RESULTS

Awareness of oral health showed the most important relationship. Different social background and economic factors also had great effects on demand. Higher demand for care were existed among those who suffered from a disease that was painful or resulted in poor oral function.

CONCLUSIONS

It is suggested that dental care has different characters from general health service. Utilization of dental service is largely determined by people's awareness, income and insurance system. So oral health education should be extended in order to promote the effective demands and reduce the potential demands. Rational oral health insurance system should be set up to provide some priority to certain people, thus stimulating the supply of dental care and improving the utilization of dental service. Since raising price for care will restrain the low-incomer's basic demand, and it will neither add the profit nor improve people's oral health, the price decision should be considered carefully. At last, oral health care should be emphasized on children and adolescent as priority age groups based on the conclusion from demand model.

Medial axis reformation: a new visualization method for CT angiography

RATIONALE AND OBJECTIVES

The authors performed this study to evaluate a new method (medial axis reformation [MAR]) for visualizing three-dimensional vascular data at electron-beam computed tomographic (CT) angiography.

MATERIALS AND METHODS

MAR was performed automatically with a personal computer-based workstation. After the region of interest was edited, voxels were divided into groups according to their path lengths. Centroids of groups were connected to form the medial axis. Then, the medial axis was refined with multiscale medial response. Bifurcations were also detected and refined. Finally, curved sections were generated through the branches and laid out onto a single image by using a splitting method. The authors performed MAR during electron-beam CT angiography of coronary arteries, common carotid arteries, and iliac arteries.

RESULTS

MAR displayed curved sections of branched vessels on one image, cut through the axis of vessels to show the vessel diameter objectively, and allowed the viewing direction to be altered arbitrarily.

CONCLUSION

Results of preliminary applications demonstrate that MAR is a valuable new visualization method for CT angiography.

Topological indices based on vertex, distance, and ring: on the boiling points of paraffins and cycloalkanes

Vertex, distance, and ring (in cyclic compounds) are three essential structure elements of a molecular graph, based on which three new topological indices VDI, OEI, and RDI are proposed. Multiple regression analysis was carried out against the boiling points of 343 hydrocarbons(160 paraffins and 183 cycloalkanes) with VDI, OEI, RDI, and N(2/3)(N is the number of carbon atoms) together, and a good QSPR model was obtained: ln(577 - Bp) = 6.729609 - 0.154107N(2/3) + 2.285632 x 10(-2)VDI - 7.921410 x 10(-3)OEI - 1.821962 x 10(-2)RDI (F = 6455.09, r = 0.9935, rms = 6.44 degrees C, n = 343).

Ethanol-induced swelling in neonatal rat primary astrocyte cultures

We tested the hypothesis that astrocytes swell in response to ethanol (EtOH) exposure. The experimental approach consisted of an electrical impedance method designed to measure cell volume. In chronic experiments, EtOH (100 mM) was added to the culture media for 1, 3, or 7 days. The cells were subsequently exposed for 15 min to isotonic buffer (122 mM NaCl) also containing 100 mM EtOH. Subsequently, the cells were washed and exposed to hypotonic buffer (112 mM NaCl) containing 100 mM mannitol. Chronic exposure to EtOH led to a marked increase in cell volume compared with control cells. Specific anion cotransport blockers, such as SITS, DIDS, furosemide, or bumetanide, when simultaneously added with EtOH to hyponatremic buffer, failed to reverse the EtOH-induced effect on swelling. In acute experiments, confluent neonatal rat primary astrocyte cultures were exposed to isotonic media (122 mM NaCl) for 15 min, followed by 45-min exposure to hypotonic media (112 mM NaCl, mimicking in vivo hyponatremic conditions associated with EtOH withdrawal) in the presence of 0-100 mM EtOH. This exposure led to a concentration-dependent increase in cell volume. Combined, these studies suggest that astrocytes exposed to EtOH accumulate compensatory organic solutes to maintain cell volume, and that in response to hyponatremia and EtOH withdrawal their volume increases to a greater extent than in cells exposed to hyponatremia alone. Furthermore, the changes associated with EtOH are osmotic in nature, and they are not reversed by anion cotransport blockers.

Localization of an insulin-like peptide in brains of two flies

A nucleotide sequence (GenBank AI134194) was identified in the database of the Berkeley Drosophila Genome Project based on the similarity of its translated sequence to insulin-like peptides known for other insects. The putative A chain of the Drosophila peptide was synthesized and used to produce an antiserum for immunocytochemistry. Medial neurosecretory cells and their axons were immunostained in whole brains of Drosophila larvae and adults. In larvae, immunostained axons from these cells extended to the corpus cardiacum in the ring gland and the hypocerebral ganglion and along the aorta in the head. In adults, axons from these cells extended along the aorta to the corpus cardiacum-hypocerebral ganglion complex near the cardiac valve and branched along the midgut and crop. In contrast, two clusters of lateral neurosecretory cells and their axons were immunostained weakly in brains of female mosquitoes, Aedes aegypti. No other cells were stained in the nervous systems or midguts of Drosophila larvae and adults or Ae. aegypti females. These specific localizations substantiate the existence of an endogenous insulin-like peptide in Drosophila and suggest that a similar peptide is present in the distantly related mosquitoes.

Distribution of ovary ecdysteroidogenic hormone I in the nervous system and gut of mosquitoes

Ovary ecdysteroidogenic hormone I (OEH I) is a gonadotropin in the female mosquito, Aedes aegypti. Whole-mount immunocytochemistry using OEH I antisera revealed an extensive distribution of immunostained cells in larvae and adults of this mosquito comparable to that observed in the African malaria mosquito, Anopheles gambiae. Medial neurosecretory cells were stained in brains of larvae and adult Ae. aegypti. In An gambiae the lateral neurosecretory cells were stained more often. In both species, immunostained axons from these cells extended out of the brain through the neurohemal organ associated with the aorta and branched extensively along the midgut. Immunostained endocrine cells were observed in larval and adult midguts of both species. In adults, abdominal metameric perivisceral organs were stained. Stained axons interconnected the perivisceral organs and neurosecretory cells in the abdominal ganglia. Episodic release of OEH I from these organs was evident in female Ae. aegypti, when staining disappeared at 12 hours after a blood meal and returned by 48 hours to levels observed before and up to 2 hours after the blood meal. Two sites were specifically stained only in An. gambiae: an axon net around the pyloric valve in the hindgut of larvae and adults and a ring of endocrine cells in the cardiac valve in the larval midgut. The markedly similar localizations of immunostained cells in larvae and adults of two distantly related species indicate that OEH I, or a homolog, is conserved within this group of Diptera and likely has stage- and sex-specific functions.

Coexpression of microsomal-type prostaglandin E synthase with cyclooxygenase-2 in brain endothelial cells of rats during endotoxin-induced fever

Fever is triggered by an elevation of prostaglandin E(2) (PGE(2)) in the brain. However, the mechanism of its elevation remains unanswered. We herein cloned the rat glutathione-dependent microsomal prostaglandin E synthase (mPGES), the terminal enzyme for PGE(2) biosynthesis, and examined its induction in the rat brain after intraperitoneal injection of pyrogen lipopolysaccharide (LPS). In Northern blot analysis, mPGES mRNA was weakly expressed in the brain under the normal conditions but was markedly induced between 2 and 4 hr after the LPS injection. In situ hybridization study revealed that LPS-induced mPGES mRNA signals were mainly associated with brain blood vessels, especially vein or venular-type ones, in the whole brain area. Immunohistochemical study demonstrated that mPGES-like immunoreactivity was expressed in the perinuclear region of brain endothelial cells, which were identified as von Willebrand factor-positive cells. Furthermore, in the perinuclear region of the endothelial cells, mPGES was colocalized with cyclooxygenase-2 (COX-2), which is the enzyme essential for the production of the mPGES substrate PGH(2). Inhibition of cyclooxygenase-2 activity resulted in suppression of both PGE(2) level in the CSF and fever (Cao et al., 1997), suggesting that the two enzymes were functionally linked and that this link is essential for fever. These results demonstrate that brain endothelial cells play an essential role in the PGE(2) production during fever by expressing COX-2 and mPGES.

The ARG tyrosine kinase interacts with Siva-1 in the apoptotic response to oxidative stress

The Abl family of mammalian nonreceptor tyrosine kinases consists of c-Abl and ARG (Abl-related gene). Certain insights are available regarding the involvement c-Abl in the response of cells to stress. ARG, however, has no known function in cell signaling. The present studies demonstrate that ARG associates with the proapoptotic Siva-1 protein. The functional significance of the ARG-Siva-1 interaction is supported by the finding that ARG is activated by oxidative stress and that this response involves ARG-mediated phosphorylation of Siva-1 on Tyr(48). The proapoptotic effects of Siva-1 are accentuated in cells stably expressing ARG and are inhibited in ARG-deficient cells. Moreover, the proapoptotic effects of Siva-1 are abrogated by mutation of the Tyr(48) site. We also show that the apoptotic response to oxidative stress is attenuated in ARG-deficient cells and that this defect is corrected by reconstituting ARG expression. These findings support a model in which the activation of ARG by oxidative stress induces apoptosis by a Siva-1-dependent mechanism.

Computer simulation of temperature changes in a wheat storage bin

A mathematical model describing the transient temperature distribution of grain in a cylindrical storage bin with mixed boundaries is presented and solved using the finite element method. Using the typical meteorological data of a region such as temperate China, temperature changes of wheat in a storage bin are simulated and analysed in detail. Simulated results indicate that high temperature accumulation areas of the grain are in the bin centre and near the bin bottom or at the top surface of the grain throughout the whole year and ventilation under appropriate weather conditions is necessary. This method can be used to develop and evaluate aeration control strategy and reduce the need for chemical treatments of grain during storage.

[Induction of protective immune responses in rhesus monkey by immunization with recombinant plasmids of polyvalent epitopes of Plasmodium falciparum using cholera toxin B as adjuvant]

The immunogenicity and protective efficacy of the DNA vaccine which include cholera toxin B subunit (CTB) and polyvalent protective epitopes of Plasmodium falciparum (awte gene) was assessed using rhesus monkeys as animal models. Recombinant plasmids of pCMV-CTB-AWTE were given to five rhesus monkeys three times with two weeks intervals by intramuscle (i.m.) route, immunization dose was 500 micrograms per plasmid per animal. High levels of anti-CTB and anti-malaria epitopes antibodies and P. falciparum epitope specific CTL activity were elicited. The vaccinated groups was challenged with 1.25 x 10(8) of P. cynomolgi parasites. All monkeys of the control group was patent for at least 34 days, the DNA vaccinated groups wasn't infected during the 60 days we detected. The cocktail DNA vaccine which contains multi-stage and multi-epitope antigen gene shows excellent immunogenicity and protective efficacy, the results also suggests that DNA vaccine plays an important role against malaria infection.

[A study on the bioavailability of fluoride added into milk]

OBJECTIVE

To assess the bioavailability of fluoride added into milk.

METHODS

Eight subjects were studied by testing fluoride levels in blood and urine samples collected after drinking fluoridated milk and fluoridated water respectively, according to pharmacokinetics and cross control method.

RESULTS

The bioavailability of fluoride in fluoridated milk reached 80.2% in blood analysis and 84.8% in urine analysis. The result was about 20.0% lower as compared with fluoridated water.

CONCLUSION

Fluoride bioavailability in fluoridated milk is still high and sufficient.

[Translation initiation function of the regulation element in the operon of cholera toxin A]

To demonstrate that there existed translation coupling between cholera toxin A subunit gene and B subunit gene, and give the answer why the expression level of B gene is five times more than that of A gene, alpha report system for the investigation of translation coupling was constructed by using lacZ gene as reporter. Frame-shift mutation was introduced near the C terminal of ctxA gene, and the ribosome would read through its normal stop codon. The report plasmid was constructed and it was found that the expression level of lacZ gene decreased five times after the frame-shift mutation. The translation of cholera toxin B subunit gene was translational coupled with A subunit gene, and was responsible for the differential expression level of the two genes.

[A new model of translational control of gene expression in polycistron++ of AB5 entrerotoxin]

The expression level of the B subunit gene of cholera toxin (ctx) and E. coli heat labile toxin (ltx) is five to seven times more than that of A subunit gene. In these studies, a 80 basepair translation regulation element was found located in the structure gene of A gene of both toxin operon which consists of three translation initiation region. Site-directed mutation of the initiation codon of TIR3 resulted in the 9 time decrease of the expression of the downstream cistron which was translational coupled with A gene. The results indicated that translation from the internal of A gene and translation coupling are responsible for the differential expression level of the A and B gene of AB5 enterotoxin.