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.

X-Ray structures of the universal translation initiation factor IF2/eIF5B: conformational changes on GDP and GTP binding

X-ray structures of the universal translation initiation factor IF2/eIF5B have been determined in three states: free enzyme, inactive IF2/eIF5B.GDP, and active IF2/eIF5B.GTP. The "chalice-shaped" enzyme is a GTPase that facilitates ribosomal subunit joining and Met-tRNA(i) binding to ribosomes in all three kingdoms of life. The conserved core of IF2/eIF5B consists of an N-terminal G domain (I) plus an EF-Tu-type beta barrel (II), followed by a novel alpha/beta/alpha-sandwich (III) connected via an alpha helix to a second EF-Tu-type beta barrel (IV). Structural comparisons reveal a molecular lever, which amplifies a modest conformational change in the Switch 2 region of the G domain induced by Mg(2+)/GTP binding over a distance of 90 A from the G domain active center to domain IV. Mechanisms of GTPase function and ribosome binding are discussed.

[An analysis on need and demand for dental service in urban residents of Beijing]

OBJECTIVE

To analyze the needs and demands for dental services in urban residents of Beijing, and to forecast developmental trends of dental demand in the future.

METHODS

There were 1,517 subjects examined by a stratified, clustering, random sampling, and a questionnaire survey were completed.

RESULTS

The prevalence of oral diseases was 97.6%, but only 31.5% of subjects visited the dentist in a year, the total number of residents who had need of dental care were 4,412,010 more than that of demand level. Potential demand was mainly due to the negative awareness of people and problem from service provider. It was predicted that, if the potential demand caused by awareness and service provider were satisfied, the demand for dental care would increase by 69.4% and 13.2%, respectively. By the year of 2005, the demand will increase by 1.14%, and the value will be 3.76% in 2010.

CONCLUSIONS

A substantial discrepancy is found between oral disease presence and demand for dental service. The levels of demand are also irrational. The large potential demand is caused by both receiver and provider's factors. At last, the future demand for dental care is forecasted under three hypothesis.

Molecular electronegative distance vector (MEDV) related to 15 properties of alkanes

Several quantitative structure-property relationship (QSPR) models between 15 basic physical properties or thermodynamic functions of alkanes and their molecular electronegative distance vectors (MEDV) are developed. For six of the properties-boiling point (BP), density (D) at 25 degrees C, refraction index (RI) at 25 degrees C, critical temperature (CT), critical pressure (CP), and surface tension (ST) at 20 degrees C-logarithmic models are found to give better results than conventional (linear) models since the values of these properties all tend to a limit with increasing carbon chain length. All models are created using multiple linear regression (MLR). Conventional models are proposed for the remaining nine physical properties or thermodynamic functions: molar volume (MV) at 20 degrees C, molar refraction (MR) at 20 degrees C, heat capacity (HC) at 300 K, enthalpy (E) at 300 K, heats of vaporization (HV) at 25 degrees C, heat of atomization (HA) at 25 degrees C, standard heat of formation (HF) at 25 degrees C, heat of formation in liquid (HFL) at 25 degrees C, and heat of formation in gas (HFG) at 25 degrees C.

Pseudosubstrate inhibition of protein kinase PKR by swine pox virus C8L gene product

The interferon-induced protein kinase PKR is activated upon binding double-stranded RNA and phosphorylates the translation initiation factor eIF2alpha on Ser-51 to inhibit protein synthesis in virally infected cells. Swinepox virus C8L and vaccinia virus K3L gene products structurally resemble the amino-terminal third of eIF2alpha. We demonstrate that the C8L protein, like the K3L protein, can reverse the toxic effects caused by high level expression of human PKR in yeast cells. In addition, expression of either the K3L or C8L gene product was found to reverse the inhibition of reporter gene translation caused by PKR expression in mammalian cells. The inhibitory function of the K3L and C8L gene products in these assays was found to be critically dependent on residues near the carboxyl-termini of the proteins including a sequence motif shared among eIF2alpha and the C8L and K3L gene products. Thus, despite significant sequence differences both the C8L and K3L proteins function as pseudosubstrate inhibitors of PKR.

[Rainfall interception capacity of forest canopy between two different stands]

Based on the observation data, the rainfall interception capacity of the canopy in plantation and natural forest stands and its relation to rainfall were examined using the method of taking maximum under the same rainfall. The results showed that the rainfall interception capacity of plantation forest increased rapidly with the increase of rainfall, because of its even distribution of branches and leaves, which was higher under low rainfall less than 30 mm, and the saturation interception capacity was easily reached, depending on the quantity of branches and leaves in the canopy. Although the interception capacity of natural forest was relatively weak under low rainfall less than 30 mm, compared with plantation forest, it was much stronger under heavy rainfall more than 30 mm. The saturation interception of natural forest was larger than that of plantation forest.

[The role of IL-1 beta and TNF-alpha in hyper-reactivity of neutrophils in rapidly progressive periodontitis patients]

OBJECTIVE

Neutrophils (PMNs) from rapidly progressive periodontitis (RPP) was found to generate abnormally high levels of oxygen radicals. Elastase activity in gingival crevicular fluid (GCF) from RPP was also found much higher. It suggested that PMNs in some RPP patients are hyper-reactive. The purpose of this study was to investigate the mechanism of PMN hyper-reactivity by surveying the correlation of TNF-alpha level with elastase activity in GCF and by evaluating the association between PMN infiltration and the expression of IL-1 beta and TNF-alpha in gingival tissues from RPP patients.

METHODS

41 GCF samples from 22 RPP patients and 34 GCF samples from 11 healthy controls were collected. The total amount of TNF-alpha in GCF was detected using ELISA. The elastase activity was measured with a low molecular weight substrate (S2484) specific for granulocyte. The correlation of TNF-alpha level with elastase activity in a GCF sample was analyzed with Spearman correlation. 20 gingival specimens were obtained respectively from 10 RPP patients and 5 periodontally healthy controls. The expression of IL-1 beta and TNF-alpha was detected with immunohistochemistry. The distribution of PMN was observed with hematoxylin and eosin staining.

RESULTS

Total amount of TNF-alpha in GCF was positively correlated with elastase activity (r = 0.44, P < 0.05). The IL-1 beta- and TNF-alpha-positive cells in gingiva were superimposed in areas where PMNs infiltration predominant.

CONCLUSION

The hyper-reactivity of PMN in RPP patients was related to locally produced IL-1 beta and TNF-alpha.

[The effect of non-surgical periodontal and adjunctive minocycline-HCL treatments on collagenase activity]

OBJECTIVE

To evaluate the effect of scaling and root planing combined with local application of 2% minocycline hydrochoride ointment(Periocline) on the level of collagenase activity releasing from PMNs in GCF.

METHODS

This was a randomized, single-blinded, split mouth design study. The target sites of 31 patients with moderate to severe periodontitis (PD > 5 mm) was randomized by left-side and right-side into one of the two groups (the test group and the control group). Subsequently each patient was scheduled for two appointments for the full-month supra-gingival scaling and oral hygiene instruction. At baseline all patients received subgingival scaling and root planing and were followed by 4-time applications of Periocline with one-week interval for totally four weeks in the test group. All patients were taken GCF for measuring collagenase by the method of Nakashima et al (1996) and were examined based on four parameters, including plaque index, pocket depth, attachment loss and bleeding on probing.

RESULTS

Four weeks after root planing with 4-time applications of Periocline, all clinical parameters and active collagenase in GCF decreased significantly in the test groups[(593 +/- 112) mU/sample vs (311 +/- 98) mU/sample, P < 0.001]. On the other hand, simple root-planing therapy had limited effect on the active collagenase[(611 +/- 123) mU/sample vs (523 +/- 127) mU/sample], although all clinical parameters were also reduce significantly. Interestingly, seven weeks later, gingival inflammation and the active collagenase were reduced more significantly than those after four-week root planing in both groups[Test: (311 +/- 98) mU/sample vs (207 +/- 57) mU/sample;

CONTROL

(523 +/- 127) mU/sample vs (345 +/- 117) mU/sample, P < 0.001]. At eleven week, gingival inflammation and the level of collagenase activity were rebounded in the control group[(467 +/- 108) mU/sample]. However, in the test group they were kept in lower level[(213 +/- 121) mU/sample]. The level of collagenase activity showed significantly positive correlation with GCF volumes and AL in two groups.

CONCLUSION

These results indicate that local application of 2% minocycline hydrochoride ointment may effectively inhibit the level of active collagenase from PMNs and may inhibit connective tissue breakdown by inhibiting neutrophil collagenase.

Peri-implant mucosal inflammation and bone loss: clinical and radiographic evaluation of 108 dental implants after 1-year loading

OBJECTIVE

To evaluate the clinical outcomes, and a possible correlation between peri-implant mucosal inflammation and marginal bone loss, 1 year after restoration in a group of Chinese patients with dental implants.

METHODS

Observation of the clinical and radiographic parameters of 108 IMZ and Frialit-2 dental implants in 70 patients.

RESULTS

One year after loading, there were no signs of mobility and peri-implant radiolucency in any of the implants. The average bone loss adjacent to implants was 0.63 mm (SD 0.78). The prevalence of peri-implant mucosal inflammation, as indicated by sulcus bleeding index (SBI) of 1.0 or more, was 32.9%. Significant positive correlation was found between mucosal inflammation and bone loss (P < 0.05). 92% of the observed sites had plaque index (PLI) scores greater than 1.

CONCLUSIONS

The 1-year outcomes from this patient group indicate that IMZ and Frialit-2 implants provide satisfactory clinical results. One of the etiologic factors of alveolar bone loss around implants seems to be plaque-associated marginal inflammation. Improvement of oral hygiene, elimination of soft tissue inflammation, and proper treatment of periodontal disease of natural teeth are critical for maintaining the implants.

[Assessment of malaria DNA vaccines in mice and monkeys]

Cholera toxin B subunit is a good carrier protein and an effective adjuvant which can boost both cellular and humoral immunity. DNA fragments encoding B cell, Th cell and CTL epitopes of P. falciparum CS, MSA-1, MSA-2 and RESA antigens were cloned down-2 stream of cholera toxin B subunit gene in the same reading frame. High titer of anti-malaria epitopes antibodies and strong cellular immunogenicity were elicited after Balb/c mice were immunized three times with 100 micrograms recombinant plasmid DNA dissolved in 100 microliters PBS. A total of 120 vaccinees were challenged with mouse Plasmodium yoelli to investigate if cross protection existed. The protective efficacy was about 60%-80%. Four rhesus monkeys were challenged with 10(8) of P. cynomalgi, better results were obtained in the groups immunized with mixed plasmids including NANP, AWTE.

2-year observation of attachment loss in a rural Chinese population

BACKGROUND

Risk indicators for periodontitis seem to vary with study population. The purpose of this study was to determine whether risk indicators of additional attachment loss differ between generations of Chinese villagers in a rural area of China over a 2-year period.

METHODS

The study population consisted of 310 subjects aged 15 to 44. In each subject, 2 quadrants from either the upper or lower jaw were randomly selected and 6 sites on each tooth were examined. Clinical parameters included plaque scoring system (PSS), calculus index (CI), probing depth (PD), attachment level (AL), and sulcus bleeding index (SBI). The second examination was done 2 years after the first.

RESULTS

In the 15- to 24-year-old age group, mean PSS, CI, and SBI were significantly higher in subjects with additional attachment loss > or =3 mm (AL+) than in those without attachment loss (AL-). In the 25- to 34-year-old age group, mean PD was significantly higher in AL+ than in AL-, and mean PD and AL were significantly higher in AL+ than in AL- in the 35- to 44-year-old age group. Although the number of subjects with AL+ increased with age, the mean number of sites with AL+ per subject did not differ by generation. In addition, smokers tended to exhibit attachment loss more often than non-smokers.

CONCLUSIONS

The present results suggest that the clinical parameters associated with attachment loss differ between generations and that gingival inflammation is likely associated with the onset of periodontitis more strongly than progression of periodontitis, whereas PD and/or AL are associated with the progression of periodontitis.

High-level expression of a truncated wall-associated protein A from the dental cariogenic Streptococcus mutans

Streptococcus mutans plays a primary role in the formation of dental caries. Previously, in our laboratory, an S. mutans genomic library was prepared, and the wapA gene was cloned into the shuttle vector, pSA4/4B2. To generate overexpression of wapA and to facilitate efficient purification of the WapA protein for use as an immunogen, an expression vector with the strong tac promoter was used. In order to answer questions regarding the optimization of solubility and expression based on gene size or the hydrophobicity of the protein product, 12 truncated constructs of the wapA gene were prepared using PCR. The truncated products were subcloned into the pGEX-6P-1 glutathione S-transferase (GST) fusion vector and expressed in E. coli BL21. The fusion proteins were analyzed by SDS-PAGE and confirmed by analysis with anti-GST and anti-WapA antibodies. Our study suggests that abrogation of the wapA promoter is necessary for expression of this gene in this expression system. Deletion of the signal peptide and the hydrophobic C terminus of WapA increased expression compared with the full-length construct, and truncation at the protease cleavage site of the C-terminal region greatly increased the stability of the protein without a loss in reactivity with the anti-WapA antibody. Western immunoblot analysis with anti-WapA antiserum clearly showed that the majority of the epitopes of the GST-WapA fusions are located in the N-terminal region of WapA. The immunogenicity of the various WapA fusion products is being examined in mice and rats to further map the immunologically dominant regions of the protein. This method effectively increased the expression of WapA and should contribute to the further understanding of gene expression of E. coli, as well as aid in the characterization of this protein for future immunologic evaluation.

[A one-year study on enzyme level in gingival crevicular fluid around osseointegrated dental implants]

OBJECTIVE

To investigate the changes of gingival crevicular fluid(GCF) volume, aspartate aminotransferase (AST) and alkaline phosphatase(ALP) levels in GCF around dental implants during the first year after rehabilitation. And to explore the relationships between these changes and peri-implant inflammation as well as bone loss.

METHODS

26 Branemark implants in 12 adults were included in this study. Examinations were carried out in a total of 52 sites in preinsertion period and 3, 6, 12 months following rehabilitation.

RESULTS

GCF volume, GCF-AST, GCF-ALP were firstly increased and then fallen during the first year after rehabilitation. GCF volume, GCF-AST, GCF-ALP in sites with peri-implant mucositis were higher than those in health sites, and were increased with the severity of peri-implant mucositis. GCF volume, GCF-AST, GCF-ALP in sites with bone loss were significantly higher than those without bone loss.

CONCLUSION

GCF volume, GCF-AST, GCF-ALP could reflect peri-implant inflammation and bone changes to some degree.

[Ecological process of vegetation restoration in Caragana mirophylla sand-fixing area]

The occurrence and development of artificial vegetation after mobile sandy dunes being fixed by adopting straw check combining with seeding Caragana microphylla were studied. Especially the process of species invasion and the changes of community structure in 35 years were analyzed in detail. The results showed that the species richness of artificial community of C. microphylla increased, from 5 species (in 2 years) to 23 species in 35 years. In the structure concerning plant lifeform, therophytes were in dominant position, while the ratio of therophytes to all plant species had a tendency of decrease. The rates of species number and the quantity of hemicryptophytes and geocryptophytes increased gradually. Species diversity and community evenness indexes increased and ecological dominance index decreased gradually. The similarity index of the artificial plant community to natural one increased with age. The changes of physical and chemical property of soil were also discussed.

[Induction of protective immune response in mice and rhesus monkeys by immunization with fusion protein of cholera toxin B subunit and multiples of Plasmodium falciparum]

Recombinant fusion protein of cholera toxin B subunit (CTB) and poly-valent protective epitopes of plasmodium falciparum was given to i.m. to C57BL/6j mice and rhesus monkeys three times. In rhesus monkeys, high level of antibodies for CTB (1:6400) and malaria epitopes (1:3200) amtobpdoes were elicited as well as the specific CTL activity for P. plasmodium. After the mice were challenged with sporozoites of P. yeolli, about 50% of them were protected from the patent infection. A blood-stage challenge with 10(8) of P. cynomolgi parasite were given to rhesus monkeys, which showed that two animals in control group were patent infection for at least 30 days, in contrast, the two animals immunized were recovered respectively at the day of 11 and 15 after challenges. The results suggested that cholera toxin acts as an effective adjuvent in the development of malaria vaccine.

[Titer and avidity of serum antibody to Porphyromonas gingivalis before and after periodontal therapy]

OBJECTIVE

To observe the changes of titer and avidity of serum antibody to Porphyromonas gingivalis (Pg) before and one month after periodontal therapy, and to observe the correlation of titer and avidity of anti-Pg IgG with clinical indices.

METHODS

ELISA and DEA-ELISA were used to determine the titer and avidity of serum IgG antibody to Pg381 before and one month after periodontal treatment in 17 periodontitis patients and 6 healthy control subjects.

RESULTS

The titers of anti-Pg IgG antibody were higher in periodontitis patients than in healthy control subjects (P < 0.001). All patients were seropositive (titers to Pg were higher than 2-fold above the median for control subjects). IgG antibody avidity to Pg in periodontitis patients were not found to be significantly lower than that in control group. The titers to Pg decreased significantly at one month after periodontal therapy, but antibody avidity didn't change. Serum anti-Pg antibody titers had a tendency of negative correlation with probing depth. The antibody titers were significant higher in periodontitis patients with < or = 5 mm mean probing depth than in patients with > 5 mm mean probing depth.

CONCLUSIONS

It is suggested that the humoral immune response to Pg381 is protective and this protective effect mainly depends on the titer of antibody.

Characterization of a novel human immunodeficiency virus type 1 neutralizable epitope within the immunodominant region of gp41

Previously, we generated human monoclonal antibodies using peripheral blood mononuclear cells from an asymptomatic human immunodeficiency virus type 1 (HIV-1)-seropositive donor. One of these monoclonal antibodies (designated clone 3, CL3) recognized 10 amino acids (GCSGKLICTT) within the immunodominant region (cluster I) of the transmembrane envelope glycoprotein gp41 and neutralized infection of target cells with different laboratory isolates. Because the epitope recognized by CL3 has two cysteine residues that could potentially produce a disulfide loop in gp41, we analyzed binding of our monoclonal antibody to the cyclic and linear motif of the peptide sequence IWGCSGKLICTTAVP (residues 600-614). The CL3 antibody did not bind to the synthetic cyclic peptide but did recognize the linear form. Two polyclonal rabbit sera against both the linear and cyclic peptides were then generated. Both antisera bound to viral glycoproteins gp41 and gp160, but neither sera neutralized HIV-1 laboratory isolates. Using a set of alanine-substituted IWGCSGKLICTTAV peptides, we analyzed binding of polyclonal antisera and CL3. The profile of binding of polyclonal antisera to these peptides was different from that of CL3 to the same peptides. This suggests that CL3 recognized a unique neutralizable core epitope, which was not immunogenic in either the cyclic or the linear IWGCSGKLICTTAVP peptides used as immunogens in the rabbits.

[Boron balance in agroecosystem on brown-red soil of south Hubei Province]

Five sequential cropping systems including rape/soybean-rice, wheat/watermelon-rice, rape/corn-soybean, wheat-sesame and soybean-sesame, were selected study the boron balance in agroecosystem on brown-red soil of south Hubei Province. The results show that the main output of boron was runoff and leaching, which accounted for 48-53% and 41% of the total respectively, while the output by products accounted for 3.4-10.1%. The main inputs were from rainfall, irrigation, fertilization seeds and seedlings, and natural return.

[Changes of elastase in gingival crevicular fluid after periodontal treatment of adult periodontitis patients]

OBJECTIVE

To examine the changes of elastase in the supernatant (EA-s) and in the pellet (EA-p) after centrifuge in gingival crevicular fluid (GCF) before and after periodontal treatment.

METHODS

GCF was sampled with filter paper strips by intra-pocket method to determine EA levels. Forty-three teeth of eight subjects were included. EA-s and EA-p were determined separately using the subtract Meosuc-ala-ala-val-pro-NA.

RESULTS

EA-s per site and per ml, EA-p per site and the ratio of EA-s/EA-p (S/P) decreased significantly after non-surgical periodontal treatment (P < 0.001), while EA-p concentration didn't change (P > 0.05).

CONCLUSIONS

GCF-EA-s and EA-p could act as objective parameters to evaluate the effect of periodontal therapy, especially EA-s and S/P, which may be sensitive diagnostic parameters for determining periodontal disease activity.

Leukocyte functions in 2 cases of Papillon-Lefèvre syndrome

AIM

To investigate the rôle of leukocytes in the pathogenesis of Papillon-Lefevre syndrome (PLS).

METHODS

Peripheral blood polymorphonuclear neutrophils (PMNs), monocytes (MNs) and gingival crevicular fluid (GCF) were obtained from 2 cases of PLS with typical features. The chemotaxis of PMNs and MNs were evaluated using a modified Boyden chamber. The adherence of PMNs was determined by adherence of PMNs to petri dishes. Interleukin-8 (IL-8) in GCF was detected by sandwich ELISA. Elastase activity in GCF was measured with a low molecular weight substrate (S-2484) specific for granulocyte elastase.

RESULTS

PMNs from both patients showed depressed chemotactic response to FMLP and IL-8. Total amounts of IL-8 in GCF from the 2 patients were much higher than those of the normal controls. Elastase activity was not significantly different from that of the controls. The adherence of PMN and the chemotaxis of MN in the 2 patients were normal.

CONCLUSION

The depressed chemotactic response of PMN leads to decreased recruitment of PMN and/or release of lysozyme from PMN in the diseased gingival tissue, increasing the susceptibility of PLS patients to periodontal infection.

[Relevance of Fc gamma R polymorphism to the susceptibility of early-onset periodontitis]

OBJECTIVE

To investigate the polymorphism of the Fc gamma R genotype and its association with the susceptibility of early-onset periodontitis (EOP).

METHODS

DNA of the white blood cells from 33 subjects with EOP and 27 healthy controls was extracted. Genotypes of the Fc gamma RIIA and Fc gamma RIIIB were determined by PCR followed by BstUI restriction endonuclease digestion and DNA sequencing, respectively. Then compared the differences in distribution of each genotype.

RESULTS

No statistical difference in distribution of Fc gamma RIIA was observed between patients and controls. However, a significant over-representation of the Fc gamma RIIIB NA1/NA1 was found in EOP.

CONCLUSION

These results suggest that the Fc gamma RIIIB NA1/NA1 may be a risk indicator for the susceptibility of the EOP.

[Gingival crevicular fluid enzyme levels at different destruction sites in the same teeth]

OBJECTIVE

To direct selecting proper sampling methods and sites in clinical research.

METHODS

Gingival crevicular fluid (GCF) was sampled separately at the mesial-buccal and distal-buccal sites in the same teeth, which were destroyed differently. Clinical parameters were recorded in the subject sites and its adjacent sites. Aspartate Aminotransferase (AST) and Alkaline Phosphatase (ALP) in the GCF were determined. Difference of the enzyme levels between the two sampling sites, and relations between the enzyme level and all the clinical parameters were assessed.

RESULTS

GCF-AST, ALP per sample at severely diseased sites were much higher than that from healthy and/or mild sites in the same teeth. Significant positive correlation (P < 0.001, r > 0.5) was demonstrated between enzyme levels in the sampling sites and probing depth (PD) and attachment level (AL) of the lingual sites. However, there was mild significant correlation (P < 0.05, r = 0.275) between ALP level in the sampling sites and PD of the proximal-buccal sites of its adjacent teeth. No significant correlation (P > 0.05) was found between AST level in the sampling sites and PD, AL of the adjacent teeth sites, and also between ALP level in the sampling sites and AL of the adjacent teeth sites.

CONCLUSION

Site-specificity of periodontal disease was further demonstrated. GCF components were influenced reciprocally more obviously in the same proximal than by other sites.

[Effect of tian ma cu zhi chongji medicinal granules (TMCZCJ) on blood rheology in hypostasis rats due to stagnation of liver-qi and learning-memory disorder in cerebral ischemia-reperfusion mice]

OBJECTIVE

To investigate the effect of TMCZCJ on the blood rheology in hypostasis rats due to stagnation of the liver-qi and on the learning-memory disorder in cerebral ischemia-reperfusion mice.

METHOD

The models of hypostasis due to stagnation of the liver-qi were made by combining irritation with hypodemic injected adrenalin and ice-bath in rats, and the models of learning-memory disorder were made by repeatedly ligating-reperfusing the bilateral carotid in mice. The hypostasis rats and learning-memory disorder mice were perorally administrated TMCZCJ(7.7, 15.4 g.kg-1) once a day, for fourteen consecutive days.

RESULT

TMCZCJ can significantly reduce plasma viscosity, blood viscosity and reduced viscosity in hypostasis rats. It can also improve the latent learning-memory capability and memory gain-repetition ability in water-maze for cerebral ischemia-reperfusion mice.

CONCLUSION

TMCZCJ can improve remarkably blood rheology in hypostasis rats and learning-memory disorder in cerebral ischemia-reperfusion mice.

Artifact detection in the PO2 and PCO2 time series monitoring data from preterm infants

BACKGROUND

Artifacts in clinical intensive care monitoring lead to false alarms and complicate later data analysis. Artifacts must be identified and processed to obtain clear information. In this paper, we present a method for detecting artifacts in PCO2 and PO2 physiological monitoring data from preterm infants. PATIENTS AND DATA: Monitored PO2 and PCO2 data (1 value per minute) from 10 preterm infants requiring intensive care were used for these experiments. A domain expert was used to review and confirm the detected artifact.

METHODS

Three different classes of artifact detectors (i.e., limit-based detectors, deviation-based detectors, and correlation-based detectors) were designed and used. Each identified artifacts from a different perspective. Integrating the individual detectors, we developed a parametric artifact detector, called ArtiDetect. By an exhaustive search in the space of ArtiDetect instances, we successfully discovered an optimal instance, denoted as ArtiDetector.

RESULTS

The sensitivity and specificity of ArtiDetector for PO2 artifacts is 95.0% (SD = 4.5%) and 94.2% (SD = 4.5%), respectively. The sensitivity and specificity of ArtiDetector for PCO2 artifacts is 97.2% (SD = 3.6%) and 94.1% (SD = 4.2%), respectively. Moreover, 97.0% and 98.0% of the artifactual episodes in the PO2 and PCO2 channels respectively are confirmed by ArtiDetector.

CONCLUSIONS

Based on the judgement of the expert, our detection method detects most PO2 and PCO2 artifacts and artifactual episodes in the 10 randomly selected preterm infants. The method makes little use of domain knowledge, and can be easily extended to detect artifacts in other monitoring channels.

Induction of diagnostic test strategies with multi-level information measures

This paper presents a method for inducing clinical diagnostic test protocols or strategies from data. We represent testing strategies as a strategy tree. To support induction of strategy tree, we define three information measures: K-level information, K-level information gain, K-level gain ratio, and K-level cost index, for test selection during strategy building. These measures generalize Quinlan's information measures used in decision tree induction. We present theoretical and experimental results to show that the K-level cost index can be used to induce strategy trees in a practical domain.

[Clinical evaluation of gingival sulcus temperature in healthy subjects]

OBJECTIVE

To evaluate gingival sulcus temperature in healthy subjects.

METHODS

Small size, high sensitivity and rapid response thermocouple was used to measure the gingival sulcus temperature in seven dental students with healthy periodontium. 28 teeth in each subject were tested.

RESULTS

For an individual subject, the gingival sulcus temperatures in all sites were always lower than sublingual temperature. There was obviously increased temperature gradient from anterior teeth to posterior teeth. The mean gingival sulcus temperatures on buccal sites were lower than that on lingual sites. There was no significant difference between maxillary and mandibular corresponding sites on lingual side. However, mandibular temperature was significantly lower than maxillary temperature on buccal side. Mandibular buccal temperature was the lowest in all tooth surfaces.

CONCLUSION

Gingival sulcus temperature in subjects with healthy periodontium is easily influenced by environmental factors.

[Genetic analysis of tooth development and eruption in 82 pairs of female-female twins]

OBJECTIVE

To study the heritability of tooth development and eruption.

METHODS

82 pairs of female-female twins between 6-12 years old were collected. Twin zygosity diagnosis were made by DNA-fingerprinting. The number of third molar present, hypodontia, upper lateral incisor malformation and the number of erupted permanent teeth were recorded by oral examination and panoramic radiographs, their heritabilities were calculated.

RESULTS

According to the level of heritability, the dental traits were aligned as follows: the number of third molars present, the upper lateral incisor malformation, hypodontia and the number of erupted permanent teeth.

CONCLUSION

Though both the tooth development and its eruption were under genetic influence, the heritability of tooth development was far more than tooth eruption.

An additional electrostatic interaction between adrenodoxin and P450c27 (CYP27A1) results in tighter binding than between adrenodoxin and p450scc (CYP11A1)

Mitochondrial cytochrome P450c27 (product of the CYP27A1 gene) is found to have significantly higher affinity for the common redox partner adrenodoxin than another mitochondrial P450, P450scc (product of the CYP11A1 gene). To investigate the basis of the approximately 30-fold difference in adrenodoxin binding, two sets of P450c27 mutants were generated, expressed in Escherichia coli, and purified. Mutations of one set were within the putative adrenodoxin-binding site containing conserved lysine residues also crucial in P450scc for binding adrenodoxin. The second set included mutations within a sequence aligning with the "meander region" of P450BM-3 proposed to be a site of redox-partner interactions in P450s (Hasemann, C. A., Kurumbail, R. G., Boddupalli, S. S., Peterson, J. A., and Deisenhofer, J. (1995) Structure 3, 41-62). Mutation of the P450c27 conserved lysines (K354A and K358A) led to a approximately 20-fold increase in apparent Ks for adrenodoxin, confirming that these two positively charged residues conserved in mitochondrial P450s are important for adrenodoxin binding. Mutation of Arg-418, conserved in the CYP27A1 family, to serine also decreased the affinity for adrenodoxin approximately 20-fold. This residue is predicted to be located in the meander region. A triple K354A/K358A/R418S mutation profoundly reduced adrenodoxin binding. Thus, in contrast to P450scc, where mutation of the two conserved positively charged residues results in virtually complete inhibition of adrenodoxin binding, in P450c27 there are three of such residues (Lys-354, Lys-358, and Arg-418) important for adrenodoxin interaction.

Lipopolysaccharide injected into the cerebral ventricle evokes fever through induction of cyclooxygenase-2 in brain endothelial cells

Activation of the arachidonic acid cascade is an essential step for the development of fever during brain inflammation. We investigated the brain sites where this activation takes place by use of a rat model of brain inflammation. Intracerebroventricular administration of lipopolysaccharide but not of its vehicle evoked fever. The fever was markedly suppressed when the rats had been pretreated with a cyclooxygenase-2-specific inhibitor. In situ hybridization and immunohistochemical studies revealed that cyclooxygenase-2 mRNA and its protein were induced by lipopolysaccharide in blood vessels near the cerebral ventricles and in those in the subarachnoidal space. Double immunohistochemical staining revealed that these cyclooxygenase-2-positive cells were mostly endothelial cells. The time course of fever and that of cyclooxygenase-2 induction in the endothelial cells were in parallel. Cyclooxygenase-2 mRNA in a certain type of telencephalic neurons was also upregulated by the intracerebroventricular administration, but this neuronal response occurred both in vehicle-injected rats and in lipopolysaccharide-injected ones to the same extent. Therefore, the neuronal response was not essential to the development of fever. These results suggest that brain endothelial cells play a crucial role in the development of fever during brain inflammation by activating their arachidonic acid cascade.

Titanium dioxide as photocatalyst on porous nickel: adsorption and the photocatalytic degradation of sulfosalicylic acid

The commonly used photocatalyst, TiO2 (anatase), has been immobilized on porous nickel using 3 wt.% polyvinyl alcohol (PVA) as the binder. The results show that sulfosalicylic acid (SSal) can be degraded on the developed catalytic system. The adsorption characteristics on TiO2-Ni system have been investigated. The observance of photocalytic degradation of SSal under pH values and initial concentrations can be explained by the adsorption behavior of SSal. The parameters of the Langmuir-Hinshelwood expression have been determined by different experimental ways and the results are satisfactory.

Artifact detection in cardiovascular time series monitoring data from preterm infants

Artifacts in clinical intensive care monitoring lead to false alarms and complicate data analysis. They must be identified and processed to obtain true information. In this paper, we present a method for detecting artifacts in heart-rate (HR) and mean blood-pressure (BP) data from a physiological monitoring system used in preterm infants. The method uses three different types of artifact detectors: limit-based detectors, deviation-based detectors, and correlation-based detectors. Each identifies artifacts in the monitoring data from a different perspective. By integrating the individual detectors, we develop a parametric artifact detector, called CVDetector. The CVDetector is parametric because its performance depends on the specific values for the parameters in its component detectors. In a huge space of CVDetector instances, we have successfully discovered an optimal CVDetector instance, denoted by CVDetector. The sensitivity and specificity of CVDetector for HR artifacts is 94.8% (SD = 7.6%) and 90.6% (SD = 6.9%), respectively. The sensitivity and specificity of CVDetector for BP artifacts is 94.2% (SD = 5.3%) and 80.0% (SD = 12.4%), respectively.

Social origins of the Chinese scientific elite

The literature on China's social stratification and mobility has discussed the roles of family background and an individual's education attainment. This article aims to extend the existing literature by examining the interplay of these two aspects in fostering a homogeneous group of scientists, the members (yuanshi) of the Chinese Academy of Sciences (CAS,Zhongguo kexueyuan). Since its establishment in 1955, honorific CAS membership has been awarded to outstanding Chinese scientists in their respective fields. As of the end of 1997, a total of 859 Chinese natural scientists, including 40 women, had been elected to the five Academic Divisions of the CAS – Mathematics and Physics, Chemistry, Biological Sciences, Earth Sciences, and Technological Sciences (Table 1) – of whom 610 were alive. They have been renowned, nationally if not internationally, for their academic achievements and contributions, and they have a reputation and prestige similar to those enjoyed by their counterparts in other countries, such as members of the National Academy of Sciences in the United States and fellows of the Royal Society in Britain. Because the occupational prestige of scientists is very high in China, as it is in other countries, and following similar research on the scientific elite, it is reasonable to define CAS members as the Chinese scientific elite.

[The elastase activity in gingival crevicular fluid from rapidly progressive periodontitis]

OBJECTIVE

It is now generally accepted that polymorphonuclear neutrophil (PMN) chemotactic defect increases the patient's susceptibility to early-onset periodontitis. However, some reports including ours have failed to show defective PMN chemotaxis in rapidly progressive periodontitis(RPP) patients. The purpose of the study was to survey the role of PMN in the progression of RPP.

METHODS

The elastase activity in gingival crevicular fluid from 22 RPP patients and 11 healthy controls were studied. For the control group and 12 RPP patients, 30 s GCF and clinical data were obtained at the first visit. For other 10 RPP patients, 30 s GCF and clinical data were collected prior to treatment and 4 weeks after scaling and root-planing. The elastase activity was measured with a low molecular weight substrate (L-Pyroglutamyl-L-prolyl-L-valine-p-nitroaniline, S2484) specific for granulocyte elastase.

RESULTS

The pre-treatment elastase activity was much higher (0.63 +/- 0.38, Abs/site) in RPP patients than that in control subjects (0.07 +/- 0.05, Abs/site). The elastase activity was positively correlated with GCF volume, probing depth, attachment loss and gingival bleeding. Scaling and root-planing resulted in decrease of both clinical data and elastase activity.

CONCLUSION

These results suggested that PMN with the increased accumulation or the increased release of lysosomal enzymes may play a role in the pathogenesis of RPP.

[Helicobacter pylori in dental plaque of periodontitis and gastric disease patients]

OBJECTIVE

To investigate whether Helicobacter pylori(Hp) is a habitant in the oral cavity.

METHODS

A polymerase chain reaction (PCR) assay with oligonucleotide primers homologous to a portion of the urease C and cytotoxin-associated gene A (cag A) of Hp was used to test for the presence of Hp in dental plaque. This assay was able to detect the expected 294 bp and 400 bp DNA fragments from as few as 100 Hp cells per reaction. Thirteen gastric disease patients (Group G) and 10 periodontitis patients (Group P) were recruited. A total of 276 supra- and subgingival plaque samples were collected, from 6 teeth in each subject for PCR assay. Clinical periodontal parameters including probing depth (PD), bleeding index (BI) and plaque index (PLI) of the sampled sites were recorded.

RESULTS

In Group G, 11 of 13 patients had at least one Hp-positive plaque sample. 28.8% of the tested samples were urease C gene positive and 3.2% were positive for both urease C and cag A genes. All the 10 patients in Group P had at least one Hp-positive plaque sample. 49.2% of the tested samples were urease C gene positive and 3.3% were positive for both of the Hp genes. The prevalence of Hp was positively correlated with probing depth and bleeding index at the sampled sites.

CONCLUSION

These results suggest that oral cavity is an ecological niche of Hp.

Electron-beam CT angiography with three-dimensional reconstruction in the evaluation of coronary artery bypass grafts

RATIONALE AND OBJECTIVES

The authors evaluated the use of electron-beam computed tomographic (CT) angiography and three-dimensional (3D) reconstruction for evaluation of coronary artery bypass grafts (CABGs).

MATERIALS AND METHODS

Sixty patients (53 men and seven women; mean age, 56 years +/- 8) with 152 CABGs (29 internal mammary artery and 123 saphenous vein grafts) underwent electron-beam CT with 3D reconstruction. The time from bypass surgery to CT scanning was 7 days to 120 months (mean, 17 months +/- 28). Enhanced single-section and flow mode studies were performed in all cases. The results were correlated with CABG operation records, and patency was determined with time-attenuation curves.

RESULTS

All patients were successfully examined. On the basis of time-attenuation curve criteria, 124 (81.6%) of 152 grafts were patent. The patency rate for the internal mammary artery subgroup was 93% (27 of 29 grafts); for the saphenous vein graft subgroup, 78.9% (97 of 123 grafts).

CONCLUSION

Used in contrast-enhanced, single-section mode and flow studies with time-attenuation curves, electron-beam CT angiography with 3D reconstruction can provide quantitative data for evaluation of CABG patency.

[Relationship between elastase activity and leukocyte counts in gingival crevicular fluid]

OBJECTIVE

To determine the relationship among the elastase(EA) activity in the supernatant (EA-s), and in the pellet (EA-p) after centrifuge, and polymorphonuclear leukocyte (PMN) counts in gingival crevicular fluid.

METHODS

Gingival crevicular fluid (GCF) was sampled with filter paper strips by intra-pocket method to determine EA levels and then with gingival crevicular washings after 24 hours at the same site for PMN counting. The levels of EA-s and EA-p were determined seperately using the subtract Meosuc-ala-ala-val-pro-NA. PMNs at the same site were counted with light microscope.

RESULTS

The research demonstrated significantly positive correlation among EA-s and EA-p per site and the PMN counts in GCF (P < 0.001).

CONCLUSION

GCF-EA-p per site could reflect the amount of PMNs collected from the pockets, and EA can be the marker of PMN in GCF.

[Chemotactic response of polymorphonuclear neutrophil to FMLP and IL-8 in rapidly progressive periodontitis patients]

OBJECTIVE

It has been reported that 48%-85% of rapidly progressive periodontitis (RPP) are associated with a defect in polymorphonuclear neutrophil (PMN) chemotactic function. However, some reports failed to detect any defect in PMN chemotaxis in RPP patients. Further, the influence of race on neutrophil function has been suggested. The purpose of the present study was to determine the PMN chemotactic function in Chinese RPP patients.

METHODS

Neutrophils were obtained from heparinized peripheral blood of 16 RPP and 14 periodontally healthy control subjects matched for age and sex. Cells were isolated by Percoll discontinuous density gradient centrifugation. Chemotaxis was evaluated using modified Boyden chamber. (N-formyl-methionyl-leucyl-phenylalanine, FMLP) (10(-8) mol/L) and IL-8 (100 micrograms/L) which is a more specific neutrophil chemokines were used in this study. The results were determined by staining the filters followed by visual counting under microscopy at 600 x. Data was analyzed using the Students' t test and the value of RPP was compared with that of control subjects(> mean +/- 2s or < mean +/- 2s).

RESULTS AND CONCLUSION

The results showed all RPP patients had normal PMN chemotactic behavior.

[Significance of bcl-2 gene breaking and bcl-2 protein expression in nasopharyngeal carcinoma]

In order to study the relationship between bcl-2 gene and nasopharyngeal carcinoma. The two hot breakpoints of bcl-2 gene and bcl-2 protein expression were examined by in situ hybridization and immunohistochemistry technique in 41 nasopharyngeal carcinoma(NPC) tissues. bcl-2 gene breakpoint were found in 4 cases of NPC(positive rate 9.8%). 34 cases of NPC expressed bcl-2 protein, the positive incidence was 82.9%. No statistically significant differences was found in histological grades. All benign lesions were negative for bcl-2 gene breaking and bcl-2 protein expression. There was no corresponding relation between bcl-2 protein expression and bcl-2 gene breaking. The results implicated that bcl-2 gene breaking may not play an important role in the pathogenesis of NPC. It also suggested that overexpression of bcl-2 protein may involved in carcinogenesis of nasopharyngeal epithelium.

Brain endothelial cells express cyclooxygenase-2 during lipopolysaccharide-induced fever: light and electron microscopic immunocytochemical studies

Cyclooxygenase-2 (COX-2), a key enzyme in the biosynthesis of prostaglandins, is induced in brain blood vessels by pyrogens, and its essential role in fever has been hypothesized. In this study, we determined (1) the type of cells that express cyclooxygenase-2 in brain blood vessels of lipopolysaccharide-treated rats, and (2) the precise relationship between the time course of fever and that of cyclooxygenase-2 protein expression in these cells. Five hours after the lipopolysaccharide injection (100 microg/kg, i.p.), cyclooxygenase-2-like immunoreactive cells were found in the parenchymal and subarachnoidal blood vessels. In these blood vessels, the cyclooxygenase-2-like immunoreactivity was restricted to the perinuclear region of the endothelial cells as revealed by a laser confocal microscopy, double-immunofluorescence staining with an endothelial marker, and immunoelectron microscopy. On the other hand, the cyclooxygenase-2-like immunoreactive cells were distinct from microglia or perivascular/meningeal macrophages as revealed by double immunostaining with macrophage/microglia-specific antibodies. Cyclooxygenase-2-like immunoreactive cells were first found at 1.5 hr after the lipopolysaccharide injection, at which time the fever had not been developed. After that, the number of cyclooxygenase-2-like immunoreactive cells and fever followed a similar time course, both being highest at 5 hr after the lipopolysaccharide injection and both returning to the baseline by 24 hr. These results demonstrate that brain endothelial cells are the primary sites where the activation of arachidonic acid cascade takes place during fever after intraperitoneal injection of lipopolysaccharide.

Three-dimensional reconstruction of electron beam computed tomography angiography for evaluating coronary artery bypass grafts

OBJECTIVES

To probe into electron beam computed tomography (EBCT) angiography and 3-D reconstruction of coronary artery bypass grafts (CABG) and to evaluate the clinical application of EBCT angiography and 3-D reconstruction of CABG.

METHODS

EBCT angiography with 3-D reconstruction was achieved in 150 patients (142 men and 8 women, mean age, 57 +/- 8 years) with 399 grafts including 100 internal mammary artery grafts (IMG), 296 saphenous vein grafts(SVG) and 3 radial artery grafts (RAG) respectively. The time from bypass surgery to EBCT scanning ranged from 7 days to 120 months, averaging 15 +/- 28 months. Enhanced single slice mode (SSM) and flow studies were performed in all patients. The results of 3-D reconstruction of CABG were compared with bypass operation records and with coronary arteriograms (7 patients).

RESULTS

150 patients underwent successfully EBCT angiography and CABG 3-D reconstruction. According to 3-D reconstruction of the coronary bypass grafts with flow studies, 318 of 399 coronary bypass grafts were patent including IMG patency in 87/100 (87%), SVG in 228/296 (77%) and RAG in 3/3 (100/100). The overall patent rate was 79.7%. In 7 patients with 12 coronary bypass grafts, EBCT studies showed graft patency (7 grafts) and occlusion (5), which were confirmed by conventional graft angiography.

CONCLUSIONS

EBCT angiography with 3-D reconstruction is effective in providing the entire anatomic structure of coronary bypass grafts and evaluating coronary bypass graft patency. EBCT flow study can provide quantitative data for evaluating coronary bypass graft patency and for supplemental diagnosis of CABG 3-D reconstruction. EBCT angiography is a noninvasive technique that could replace conventional coronary arteriography for follow-up survey of coronary bypass surgery in future.

Dynamic decision analysis in medicine: a data-driven approach

Dynamic decision analysis concerns decision problems in which both time and uncertainty are explicitly considered. Two major challenges in dynamic decision analysis are on proper formulation of a model for the problem and effective elicitation of the numerous time-dependent conditional probabilities for the model. Based on a new, general dynamic decision modeling framework called DynaMoL (Dynamic decision Modeling Language), we propose a data-driven approach to addressing these issues. Our approach uses available problem data from large medical databases, guides the decision modeling at a proper level of abstraction and establishes a Bayesian learning method for automatic extraction of the probabilistic parameters. We demonstrate the theoretical implications and practical promises of this new approach to dynamic decision analysis in medicine through a comprehensive case study in the optimal follow-up of patients after curative colorectal cancer surgery.

Cyclooxygenase-2 is induced in brain blood vessels during fever evoked by peripheral or central administration of tumor necrosis factor

Cyclooxygenase-2 (COX-2) is an inducible type of enzyme that is involved in prostaglandin biosynthesis. In the present study, we examined whether or not COX-2 is involved in fever that is induced by tumor necrosis factor-alpha (TNF-alpha) and, if so, where in the brain COX-2 is induced by this factor. Intraperitoneal (i.p.) injection of TNF-alpha into rats evoked a fever that started 1 h after the TNF injection, peaked 3 h after the injection, and then gradually declined. The fever was suppressed by pretreatment with a COX-2-specific inhibitor. With a time course similar to that of fever, COX-2 mRNA was induced in brain blood vessels. On the other hand, in some of the telencephalic neurons, COX-2 mRNA was constitutively expressed under the normal condition; but its level gradually decreased during the course of fever. Fever was also evoked by an intracerebroventricular (i.c.v.) injection of TNF-alpha. This febrile response was also suppressed by a COX-2 specific inhibitor and was associated with the induction of COX-2 mRNA in the brain blood vessels. On the other hand, the telencephalic neurons did not show consistent change in COX-2 mRNA level after i.c.v. injection of TNF-alpha or saline. COX-2-like immunoreactivity was found in some cells of the brain blood vessels 3 h after the TNF-alpha injection by either i.p. or i.c.v. route. Most of the COX-2-like immunoreactive cells were endothelial cells since COX-2-like immunoreactivity was colocalized with von Willebrand factor, an endothelial cell marker, in the same cells. These results suggest that the brain blood vessels are the major sites where TNF-alpha enhances PG biosynthesis after peripheral as well as after central injection, and provides further evidence supporting the hypothesis that COX-2 induced in the brain blood vessels is involved in fever.