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.

[Existence of IL-8 degrading protease and anti-IL-8 IgG in gingival crevicular fluid]

OBJECTIVE

To identify the nature of the IL-8 inhibitor(s) in gingival crevicul fluid (GCF).

METHODS

(1) 14 GCF samples were collected from 13 adult periodontitis (AP) patients, and 9 samples were taken from 8 healthy subjects. Each GCF sample was divided into two aliquots. A serine protease-specific inhibitor-PMSF was added to one aliquot and PBS added to the other aliquot as control. ELISA was used to measure IL-8 level in the samples. (2) 41 GCF samples were collected from 15 AP patients and indirect ELISA was performed to detect the anti-IL-8 IgG antibody.

RESULTS

(1) IL-8 level in the PMSF-added samples were significantly greater than that in the control group(3.01 mg/L +/- 5.79 mg/L vs 0.05 mg/L +/- 0.15 mg/L, P < 0.001). (2) The mean value of anti-IL-8 IgG in GCF was greater than that of negative control +3 x s.

CONCLUSION

A serine protease which can "cleave" IL-8 exists in GCF and GCF from AP sites contain auto-antibody against IL-8.

[One stage repair of intraoral defects after radical operation of oral carcinoma by facial vessels pedicled naso-labial myocutaneous flap]

In order to repair the intraoral defects after extensive resection of oral carcinoma with radical neck lymph nodes dissection, the nasolabial myocutaneous flap was prepared with its pedicle which only contained the facial artery and anterior facial vein. After removal of the tumor, the flap was used to cover the intraoral defect. Altogether 15 cases of oral squamous cell carcinoma were treated by this method. Seven out of 15 cases had their cervical lymph nodes involved. The tumor in all cases were located in one anatomical region, without involvement of accessory nerve or metastasis. All the flaps survived after the operation. There was no recurrence of tumor in any case after being followed up from 0.5-2 years. Removal of tumor and repaire of the defect by pedided naso-labial myocutaneous flap could be done in one stage. The detail of the process was introduced. Its feasibility and application were discussed. It was suggested that preserving the facial vessels be a kind of modified method of radical neck lymph nodes dissection, and the nasolabial myocutaneous flap have some clinical value in repair of the defect after radical operation of oral carcinoma.

Inhibition of FtsZ polymerization by SulA, an inhibitor of septation in Escherichia coli

The bacterial cell division protein FtsZ assembles into the cytokinetic Z ring that directs cytokinesis in prokaryotes. In Escherichia coli the formation of the Z ring is prevented by induction of the cell division inhibitor SulA (SfiA), a component of the SOS response. Here we show that a MalE-SulA fusion that retains this inhibitory function in vivo inhibits the GTPase activity and polymerization of FtsZ in vitro. MalE-SulA10, which does not block Z ring formation in vivo, is unable to inhibit the GTPase activity and polymerization in vitro. Furthermore, FtsZ114, which is refractory to SulA in vivo, is not inhibited by MalE-SulA. These results indicate that SulA blocks Z ring formation by blocking FtsZ polymerization.

[Comparison of sampling methods and their effects on alkaline phosphatase levels in gingival crevicular fluid]

OBJECTIVE

To observe the change of alkaline phosphatase (ALP) after repeat sampling and compare the two sampling methods (orifice method and intra-pocket method).

METHODS

Gingival crevicular fluid (GCF) was sampled repeatedly by the interval of 20 minutes, with orifice and intra-pocket method respectively, and the levels of ALP in GCF were determined.

RESULTS

Mean levels of ALP per site and concentration of ALP are not statistically different between two samples after repeat sampling with-orifice method as well as intra-pocket method (P > 0.05). ALP levels (per site and per microliter) are much higher for intra-pocket method than orifice method (P < 0.001). From the viewpoint of the numbers of recovery sites after repeat sampling, though ALP levels at most sites can't entirely recover to their original levels with both method, intra-pocket method is still a little better than orifice method, and ALP levels per site is better than ALP concentration.

CONCLUSION

The interval of repeat sampling should be prolonged more than 20 minutes. It is better to determine the GCF-ALP with intra-pocket method and also the recommended pattern that express enzyme levels is total activity per site but not concentration.

[Reconstruction of the floor of mouth with facial artery musculocutaneous flap]

In order to study the clinical efficacy of facial artery musculocutaneous flap on repairing the defect of the floor of mouth, 21 patients had received this type of treatment from 1991 to 1997. The size of the flaps ranged from 8.0 x 3.4 cm to 12.1 x 5.4 cm and the average age of these patients was 59.5 years old. The donor site was closed directly. Nineteen flaps survived completely, while necrosis occurred at the apex of the other 2 flaps, which healed by ordinary management. The applied anatomy of the flap and the design and the main points of the operation were reported in details. The advantage of the flap and the prevention of facial malformation following operation were discussed. The conclusion was that this type of flap was ideal for reconstruction of the defects of floor of the mouth.

Modelling medical decisions in DynaMoL: a new general framework of dynamic decision analysis

Dynamic decision analysis concerns decision problems in which both time and uncertainty are explicitly considered. We present a new dynamic decision analysis framework, called DynamoL, that supports graphical presentation of the decision factors in multiple perspectives. To alleviate the difficulty in assessing conditional probabilities over time in dynamic decision models, DynaMoL incorporates a Bayesian learning system to automatically learn the probabilistic parameters from large medical databases. We describe the DynaMoL modeling and learning architecture through a medical decision problem on the optimal follow-up schedule for patients after curative colorectal cancer surgery. We also show that the modeling experience and results indicate practical promise for the framework.

Sudden turns and stops while walking: kinematic sources of age and gender differences

Background: Significant age and gender differences were found among healthy young and older adult subjects in their abilities to quickly turn or stop in order to avoid obstacles that suddenly appear in the gait path (Cao C, Ashton-Miller JA, Schultz AB, Alexander NB. Abilities to turn suddenly: effects of age, gender and available response time. J Gerontol Med Sci 1997;52A:M88-M93; Cao C, Ashton-Miller JA, Schultz AB, Alexander NB. Abilities to stop suddenly: effects of age, gender, gait phase, and available response time. Submitted for publication, 1997 (also available as a chapter in Cao C. Biomechanics of forward momentum arrest when walking: age and gender differences. PhD Dissertation, University of Michigan, 1996). The present study quantified the extent to which age and gender differences in those subjects' response kinematics affected the total time they needed to suddenly arrest their forward momentum. Methods: Age- and gender-group means of four measures of forward movement of the anterior surface of the abdomen were obtained: the duration of the first post-cue response phase, from the visual cue that initiated the arrest response to reaching peak velocity (T1); acceleration (A1) during this phase; and decelerations (D2 and D3) during two subsequent post-cue response phases. A three-line-segment representation of this forward velocity history was constructed. This representation was used to predict the differences in response time needed (NRT) to suddenly arrest momentum that resulted from measured age and gender differences in each of the four response kinematics measures. Results: The largest contributor to the age group difference found in NRT was the increase in T1 among the older adults. Among the older males, the next largest contributor was their larger value of A1, and among the older females, their substantially smaller value of D2. Among the young adults in sudden turns, no single kinematic parameter seemed primarily responsible for the gender difference found in the NRT. Among the older adults, the gender difference in D2 was almost fully responsible for the gender difference in NRT, in both sudden stops and turns. Conclusions: Much of the older adults' need for longer response times than those of the young was attributable to the lengthened first phase of their responses. Older females, in addition, needed longer response times than young adults or older males because, during the second phase of their responses, their decelerations were substantially smaller. These age and gender differences may have arisen in part from known age and gender differences in abilities to develop lower extremity joint torque strengths rapidly. Copyright 1998 Elsevier Science B.V.

[The evidence for existence of interleukin 8 inhibitor and its biological activity in gingival crevicular fluid]

In order to confirm the existence of Interleukin-8 (IL-8) inhibitor and its biological activity in gingival crevicular fluid (GCF), this study examined the GCF taken from 7 adult periodontitis (AP) patients. In neutralization test of IL-8, the results showed that the mean level of IL-8 was less than 1 ng/ml, which had been added into the GCF before ELESAs was performed to measure the amount of IL-8 in GCF. The mean level of IL-8 in the GCF of AP group was significantly lower than that of healthy group (P < 0.001). In biological activity test of IL-8 inhibitor, using pooled GCF taken from 8 AP patients (23 teeth), the results showed that the GCF (without recombinant human IL-8, rhIL-8) caused more white blood cell (WBC) migration than blank control group (physiological saline) did. When the amount of rhIL-8 increased in GCF from 0.1 microgram to 1 microgram, the WBC count increased by 18.6% which was less than the increase rate (49.1%) in control group with same dose of IL-8. In the saline group containing rhIL-8, the WBC chemotactic response appeared as an inverted "V"-shape curve. All these data suggested that 1. Certain kinds of IL-8 inhibitor exist in GCF which can "cleave" IL-8. 2. The level of IL-8 inhibitor(s) increases significantly in the GCF from periodontitis sites. 3. The GCF of adult periodontitis patient has strong chemotactic effects on WBC. IL-8 inhibitor(s) in GCF can slightly suppress the chemotactic effect induced by IL-8. When assessing the role of IL-8 in pathophysiology, the high and low dose of IL-8 might have different sense.

Analysis of the interaction of FtsZ with itself, GTP, and FtsA

The interaction of FtsZ with itself, GTP, and FtsA was examined by analyzing the sensitivity of FtsZ to proteolysis and by using the yeast two-hybrid system. The N-terminal conserved domain consisting of 320 amino acids bound GTP, and a central region of FtsZ, encompassing slightly more than half of the protein, was cross-linked to GTP. Site-directed mutagenesis revealed that none of six highly conserved aspartic acid and asparagine residues were required for GTP binding. These results indicate that the specificity determinants for GTP binding are different than those for the GTPase superfamily. The N-terminal conserved domain of FtsZ contained a site for self-interaction that is conserved between FtsZ proteins from distantly related bacterial species. FtsZ320, which was truncated at the end of the conserved domain, was a potent inhibitor of division although it expressed normal GTPase activity and could polymerize. FtsZ was also found to interact directly with FtsA, and this interaction could also be observed between these proteins from distantly related bacterial species.

[An investigation on peri-implant status in different types of dental implant]

Clinical, biochemical and microbiological methods were used to study the peri-implant status in different types of dental implant. Sixteen normal healthy adults with 12 one-stage implants and 22 two-stage implants were included in this study. Clinical parameters, proportion of subgingival spirochetes, detection rate of spirochetes were found to be significantly higher around one-stage implants than those around two-stage implants. No significant difference in gingival crevicular fluid flow, levels of aspartate aminotransferase and alkaline phosphatase was found between these two types. The bleeding index score in sites which harbored spirochetes was significantly higher than that in sites without spirochetes. The present data suggested that accumulation of plaque and existance of periodontal pathogens maybe related to peri-implant inflammation. This study suggests that plaque control and regular recall should be emphasized in implant maintenance.

[A longitudinal study of alveolar bone repair following non-surgical treatment in periodontitis]

The purpose of this study was to monitor post-treatment alveolar bone repair using digital subtraction radiography (DSR). 104 interproximal bone crestal sites were selected from 52 premolars in 9 periodontitis patients (6 male, 3 female, aged 29-63 years). Acrylic stents were used to ensure serial radiographs which were taken at initial visit, 2 weeks, and 1, 2, 3, 6, 9, 12 month(s) after scaling and root planning. Results showed: in some of the observed sites, small amount of bone increase was detected as early as two weeks after the non-surgical therapy. Statistically significant bone gain (P < 0.001) occurred at second month and peaked at 12 months after instrumentation. The increment of bone gain displayed an exponential curve. Three different patterns of alveolar bone reaction to treatment appeared among different patients. This study demonstrates that DSR is a sensitive and quantitative method in the monitor of bone fill after periodontal treatment.

Detection of stromal cells in peripheral blood progenitor cell collections from breast cancer patients

Transplantation of growth factor-mobilized peripheral blood progenitor cells (PBPC) is widely used in the treatment of several neoplastic diseases. While in PBPC harvests the presence of several accessory immune and tumor cells has been documented, that of stromal cells has not been reported. In the present study, we investigated for the presence of stromal cells in growth factor-mobilized PBPC harvests from breast cancer patients. Low-density cells from PBCP harvests in culture gave rise to an adherent layer containing fibroblast-like and large flat round cells. These cells express positive immunofluorescence staining for collagen I, collagen III, fibronectin, VCAM-1 (CD106), ICAM-1 (CD54) and mesenchymal antigens recognized by monoclonal antibodies, SH2 and SH3. PBPC-derived stromal cells do not express antigens CD34, CD45 and CD14. Stromal cells were detected in the PBPC harvests of 11/14 patients (median 0.63%; range 0.02-2.32) and their concentration correlates with the number of CD34+ cells in PBPC.

Temperature shift experiments with an ftsZ84(Ts) strain reveal rapid dynamics of FtsZ localization and indicate that the Z ring is required throughout septation and cannot reoccupy division sites once constriction has initiated

FtsZ is an essential division protein in bacteria that functions by forming a ring at midcell that mediates septation. To further study the function of the Z ring the effect of a temperature-sensitive mutation, ftsZ84(Ts), on ring dynamics and septal progression was examined. Shifting a strain carrying an ftsZ84(Ts) mutation to the nonpermissive temperature led to loss of Z rings within 1 min. Septal ingrowth was immediately inhibited, and sharply demarcated septa, present at the time of the shift, were gradually replaced by blunted septa. These results indicate that the Z ring is required throughout septation. Shifting filaments to permissive temperature led to a rapid localization of FtsZ84 at regular intervals. Included in these localization events were complete and partial rings as well as spots, although some of these eventually aborted. These results reveal the rapid dynamics of FtsZ localization and indicate that nucleation sites are formed in the absence of FtsZ function. Interestingly, Z rings could not reform at division sites that were constricted although they could reform at sites that had not begun constriction.

FtsN, a late recruit to the septum in Escherichia coli

The localization of FtsN in Escherichia coli was inves tigated by immunofluorescence microscopy. FtsN is an essential cell division protein with a simple bitopic topology, a short N-terminal cytoplasmic segment fused to a large carboxy periplasmic domain through a single transmembrane domain. FtsN was found to localize to the septum in a ring pattern similar to that observed for FtsZ and FtsA, although the frequency of cells with rings was less. A MalG-FtsN fusion was also localized to the septum, indicating that the information for FtsN localization is supplied by its periplasmic domain. FtsN localization was dependent upon the prior localization of FtsZ and FtsA and required the function of FtsI and FtsQ. Consistent with FtsN functioning after FtsZ, Z rings were observed in a mutant depleted of FtsN.

[The effect of artificial traumatic occlusion on the pulp and periodontium in rat molars]

In order to study relationship between the period of occlusal trauma and pulpal and periodontal tissues, 44 rats were used in experimental occlusal trauma. The pulpal and periodontal tissues of rat molars were observed by histological examination and micrographic examination. The results showed that the damage of pulp became more serious as time went on, but periodontium appeared adaptive changes. The same changing area in periodontal tissues were observed between histological section and micrographic film. The results provide experimental evidences for the pathology and pathogeny of pulpitis and perioapical periodontitis caused by occlusal trauma.

Involvement of cyclooxygenase-2 in LPS-induced fever and regulation of its mRNA by LPS in the rat brain

We previously showed that a febrile dose of lipopolysaccharide (LPS) in rats resulted in induction of cyclooxygenase-2 (COX-2) mRNA in brain blood vessels/leptomeninges and telencephalic neurons. To elucidate the causal link between fever and LPS-induced COX-2 mRNA, we experimentally modified one or the other of these parameters and examined their relation. 1) LPS-induced fever was suppressed by pretreatment with a COX-2-specific inhibitor. 2) Levels of COX-2 mRNA in the neurons and blood vessels 2.5 h after LPS administration were even higher in the inhibitor-pretreated rats (afebrile) than in vehicle-pretreated ones (febrile). 3) After repeated administration of LPS, rats became tolerant to LPS, in which state LPS induced neither fever nor COX-2 mRNA in blood vessels/leptomeninges. When rats had not completely established LPS tolerance, they showed various degrees of fever that were closely correlated with the level of COX-2 mRNA in blood vessels but not with that in neurons. 4) Urethan anesthesia reduced basal as well as LPS-induced COX-2 mRNA in telencephalic neurons, but the rats still responded to LPS with fever and induction of COX-2 mRNA in the blood vessels/leptomeninges. These results suggest that COX-2 induced in brain blood vessels/leptomeninges is involved in the molecular mechanism of LPS-induced fever.

[Interleukin-8, a regulator of inflammation in gingival crevicular fluid]

The role of interleuking-8 (IL-8), a neutrophil-attracting and-activating cytokine, was investigated in gingival crevicular fluid (GCF). ELISA was used to detect the levels of IL-8 in GCF collected from 54 adult periodontitis (AP) patients (105 teeth) and 24 healthy subjects (54 teeth). The results showed that 1. The role of IL-8 was dependent upon the concentration of IL-8 in GCF. IL-8, in the low concentration (< or = 30 micrograms/L), was positively correlated with bleeding index (r = 0.36, P < 0.01). While in the high concentration (> 30 micrograms/L), was negatively correlated with bleeding index and probing depth (r = -0.54 and r = -0.65 respectively, P < 0.01). In the majority of periodontitis sites (91%), the concentration of IL-8 in GCF were lower than 30 microliters/L. IL-8 most likely acted as pro-inflammatory factor in these teeth. 2. IL-8 was a two-way regulator of inflammation, pro-inflammation and anti-inflammation. The threshold of IL-8 between inducing and suppressing inflammation was approximately 30 micrograms/L. Within the confined range, IL-8 concentration greater than 30 micrograms/L could be inflammation suppressive, while a less-than-30 micrograms/L concentration of IL-8 might become inflammation inducing.

Induction of cyclooxygenase-2 in the brain by cytokines

The present study revealed that (1) a pyrogenic dose of IL-1 beta induced COX-2 mRNA in the brain vasculature and leptomeninges, and (2) the cells positive for COX-2 mRNA in the blood vessels were endothelial cells that possess receptors for IL-1. These results imply that circulating IL-1 beta acts on its receptor on the endothelial cells of the brain vasculature to induce COX-2 mRNA, which is possibly responsible for the elevated level of PGE2 seen during fever. In this sense, the endothelial cells in the brain vasculatures seem to play a role as an interface between the blood borne substance and the brain. The nature of the COX-2 mRNA-positive cells in the leptomeninges will be identified in our future study.

Possible role of cyclooxygenase-2 in the brain vasculature in febrile response

These results support the hypothesis that the brain vasculature is the site of PGE2 production responsible for LPS-induced fever. LPS seems to increase the PGE2 level in the entire brain via the induction of COX-2. Fever may be mediated by PGE2 which is produced in the blood vessels in the preoptic area or which is produced in other parts of the brain and transported to the preoptic area through the ventricular system.

Abilities to turn suddenly while walking: effects of age, gender, and available response time

BACKGROUND

Falls may occur when an unexpected turn must be made quickly, in order to avoid colliding with an object in the gait path. Little is known about abilities, particularly about abilities of old adults, to turn suddenly.

METHODS

Twenty young and 20 old (mean age 73.8) healthy and physically active adults, while walking straight ahead, were cued to make approximately a 90 degrees turn without advance knowledge of where the turn was to be made or whether it would be to the right or left. Subjects were given available response times (ART), the times between the cue to turn, and potential crossing of a specified forward limit line, of 375, 450, 600, and 750 ms. The rate of success (RS) in completing the turns as prescribed was determined. Regression analyses were used to estimate the additional ART that would be needed for other groups to achieve the same RS as did the young male subject group.

RESULTS

For all ART, old subjects had a lower rate of success in completing the turns as prescribed than the young. At an ART of 375 ms, mean RS was 36% for the young and 6% for the old. The regression analyses suggested that, for RS from 30 to 95%, old adults needed 112 ms longer than young of corresponding gender to succeed as well. Females needed on the order of 50 ms longer ART than males of corresponding age.

CONCLUSIONS

There are significant age and gender differences among healthy and physically active adults in the available response times they need when walking for successfully making sudden turns.

[Clinical studies on pulpitis and periapical periodontitis caused by traumatic occlusion]

89 cases including 100 teeth with pulpitis and apical periodontitis caused by traumatic occlusion were clinically observed. All teeth are caries-free, no any dental disease, and no pocket formation. But there is a distinct evidence of marked occlusal trauma, such as premature contact and occlusal interference. The single-root teeth are usually involved. When subjected to vitality testing the teeth associated with the periapical lesions sometimes yield positive response (about 30%). The result of investigation endodontic treatment demonstrated that the presence of predisposing factors of trauma from occlusion led to decrease of endodontic success.

[A promoter responsible for over-expression of cholera toxin B subunit in cholera toxin A subunit structure gene]

A promoter sequence, which promotes the transcription of cholera toxin B subunit gene, was found in cholera toxin A subunit structure gene. The transcription starts at the adenine Located at +833, that is 456bp upstream to the A of the initiation codon ATG of cholera toxin B gene. Under the control of the promoter, cholera toxin B subunit was over-expressed as high as 200 mg/L at an optimized culture condition. The chloramphenicol acetyl transferase gene and beta-galactosidase could also be efficiently expressed under the direction of the promoter. This promoter may be responsible for the 6 fold and 7 fold higher expression level of cholera toxin B subunit than cholera toxin A subunit in V. cholerae and Escheria coli respectively. The over-expression of CTB may be useful in preparing vaccine against cholera and facilitating the construction of peptide-bearing immunogenic hybrid proteins.

[Studies on distribution patterns of modulator CGRP in different motoneuron pools in rats]

Using retrograde labelling combined with calcitonin gene-related peptide (CGRP) immunocytochemistry technique, distribution patterns of the content of calcitonin gene-related peptide-like immunoreactivity (CGRP-LI) were studied in two different motoneuron (Mn) pools supplying soleus (SOL, slow-twitch muscle) and extensor digitorium longus (EDL, fast-twitch muscle) of hindlimbs in rats during development. The Mn pools were identified with a novel retrograde tracer, choleragen B subunit (CB) coupled with colloidal gold (CB-Au, 5 nm particle, prepared by ourselves), which was injected into EDL or SOL. After the silver intensification for visualizing colloidal gold particles, CGRP immunocytochemistry were processed. The CB-Au retrogradely identified Mns in each Mn pool were counted and CGRP-LI intensity of Mns was evaluated as strong, moderate, weak and negative. The double labelling revealed different distribution patterns of CGRP-LI content between SOL and EDL Mn pools during development. Comparing the level of CGRP expression between the two Mn pools, SOL Mn pool had a higher ratio of neurons lacking CGRP-LI/weak CGRP LI and a lower proportion of strongly CGRP-LI labelled ones. These results suggest that the difference in content of CGRP-LI in Mns is related to the type of muscular motor activity.

[The effect of sampling repetition on gingival crevicular fluid and aspartate aminotransferase activity]

The purpose of the present investigation was to evaluate the influence on sampling repetition of aspartate aminotransferase (AST) level with 10-minute intervals. Tests based on the composition of gingival crevicular fluid (GCF) for detection of active periodontitis and GCF require the repetition of sampling. Two 30-second samples of GCF were harvested with 10-minute intervals from 123 sites in 10 healthy subjects and 20 periodontitis patients. AST activity of the first samples in periodontitis subjects were approximately 7.8% greater than that of the second samples. The difference were not significant (P > 0.05). But in healthy subjects the difference were significant (P < 0.05). AST activity correlation positively with bleeding index (BI) and probing pocket depth (PD).

Endothelial cells of the rat brain vasculature express cyclooxygenase-2 mRNA in response to systemic interleukin-1 beta: a possible site of prostaglandin synthesis responsible for fever

We previously showed that intraperitoneal injection of lipopolysaccharide induced cyclooxygenase-2 (COX-2) mRNA in as yet unidentified cells of blood vessels and leptomeninges in the rat brain and proposed a possible role of these cells as the source of prostaglandin E2 in the genesis of fever (Cao et al., Brain Res., 697 (1995) 187-196). In the present study, to proceed further with this line of research, we addressed the following two questions: first, does a pyrogenic dose of interleukin-1 beta (IL-1 beta), an endogenous pyrogen, induce COX-2 mRNA in the brain blood vessels and leptomeninges? Secondly, if it does, what type of cells are positive for COX-2 mRNA? Intraperitoneal injection of recombinant human IL-1 beta (30 micrograms/kg) induced fever in rats and an in situ hybridization study revealed that faint but significant COX-2 mRNA signals appeared in the blood vessels and leptomeninges at 1.5 h after the injection (the early rising phase of fever). The mRNA signals increased in number and intensity at 4 h (early plateau phase), decreased at 6.5 h (early recovery phase), and completely disappeared by 10 h after the injection (late recovery phase). The COX-2 mRNA positive cells in the blood vessels were likely to be the endothelial cells since the corresponding cells in the adjacent mirror-imaged section also expressed mRNAs for intracellular adhesion molecule-1 and the type-I interleukin-1 receptor, although those in the leptomeninges still remained unidentified. These results imply that circulating IL-1 beta acts on its receptor on the endothelial cells of the brain vasculature to induce COX-2 mRNA, which is possibly responsible for the elevated level of PGE2 seen during fever.

Interaction between FtsZ and inhibitors of cell division

The interaction between inhibitors of cell division and FtsZ were assessed by using the yeast two-hybrid system. An interaction was observed between FtsZ and SulA, a component of the SOS response, and the interacting regions were mapped to their conserved domains. This interaction was reduced by mutations in sulA and by most mutations in ftsZ that make cell refractory to sulA. No interaction was detected between FtsZ and MinCD, an inhibitory component of the site selection system. However, interactions were observed among various members of the Min system, and MinE was found to reduce the interaction between MinC and MinD. The implications of these findings for cell division are discussed.

[Tropisetron for the prevention of nausea and vomiting during chemotherapy: multicenter clinical study]

The antiemetic effect of tropisetron was studied in 97 cancer patients (67 men, 30 women) receiving cisplatin in doses of 75 mg/m2 or higher. On 279 chemotherapy cycles studied (max 6 per patient) 5 mg of tropisetron was administered once a day i.v on day 1 and p.o. on days 2 to 6. Efficacy preventing vomiting and nausea was measured in 24 hour period as: complete control O episodes, major control 1 to 2 episodes, minor control 3 to 4 episodes and no control 5 or more episodes. Satisfactory vomiting control (complete and major) was 69%, 63%, 82%, 88%, 96% and 96% in days 1 to 6 of cycle 1. Satisfactory nausea control (complete and major) for the same days was 70%, 66%, 72%, 85%, 92% and 97%. Similar data was obtained for the subsequent cycles. Complete vomiting control was obtained in 47%, 35%, 56%, 72%, 81% and 84% and for nausea in 42%, 39%, 48%, 64%, 81% and 87%. 19 patients presented adverse effects (19.6%). Only 2 headache episodes had a definite relation with the antiemetic drug. 12 patients discontinued the medication; 6 due to drug inefficacy, 2 to illness unrelated to the drug, 1 to lack of collaboration, and 3 due to other reasons. We conclude that tropisetron allows satisfactory control of acute and delayed vomiting in a high percentage of patients treated with high doses of cisplatin. The drug does not have significant secondary effects. Tropisetron administration in only one daily dose implies an evident advantage and a treatment cost reduction.

Diagnosis of hepatitis C Virus (HCV) infection by antigen-capturing ELISA

BACKGROUND

Hepatitis C virus (HCV) is a major cause of non-A non-B hepatitis. Detection of circulating antibodies against HCV by enzyme-linked immunosorbent assay (ELISA) has provided the main approach for the diagnosis of HCV infection. Most ELISA kits use a mixture of core, NS3, NS4 and NS5 antigen as capture antigens and enzyme-labeled goat anti-human IgG as conjugate.

OBJECTIVES

To establish an ELISA system based on the antigen-capturing principle, using a recombinant chimeric polyprotein containing four HCV antigenic components as antigen.

STUDY DESIGN

HCV antigens were expressed in Escherichia coli as chimeric polyprotein either in inclusion bodies or in soluble form. Protein expressed in inclusion bodies was used as solid-phase antigen, and the antigen expressed in a soluble form was used as enzyme conjugate after being labeled with horseradish peroxidase (HRP).

RESULTS

Genes coding HCV antigens were cloned and sequenced, chimeric polyproteins containing four immunodominant components (core, NS3, NS4 and NS5) were expressed in E. coli both in soluble and in inclusion body form. These two chimeric proteins retained the antigenicity of HCV antigens. Antibody-capturing ELISA using the chimeric antigens showed a sensitivity of 97% (97/100) and a specificity of 98% (97/99) using the reference panel from the National Institute for the Control of Pharmaceutic and Biological Products of China (NICPBC); the same assay showed a sensitivity of 97.9% (48/49) and a specificity of 100% (43/43) using the self-established reference panel. Antigen-capturing ELISA was set up using the antigen labeled with horseradish peroxidase as conjugate, and was shown to be as sensitive as (97.9%) and more specific than (100%) antibody-capturing ELISA using the reference panel in this work. The antigen-capturing ELISA also showed a high accordance (98.9%) with UBI HCV enzyme immunoassay (EIA) 4.0 kits (United Biomedical Inc. USA).

CONCLUSION

Antigen-capturing ELISA provided a convenient, sensitive and more specific approach for the diagnosis of hepatitis C virus infection.

[Experimental study on uptake of fluoride by dentin after pulsed Nd:YAG laser irradiation]

The purpose of this study was to determine the uptake of fluoride by dentin after pulsed Nd:YAG laser irradiation. Under SEM examination dentin lased by pulsed Nd:YAG laser appeared to be melted; there were no changes of calcium and phosphorus levels. Dentin irradiated by pulsed Nd:YAG laser and treated with 38% Ag(NH3)2F showed greater uptake and deep penetration of fluoride than topical application of fluoride alone, SEM examination revealed that CaF2-like and Ag3PO4-like deposits were formed on the dentin surface. These results suggested that pulsed Nd:YAG laser irradition could improve the absorption of fluoride in dentin.

[Clinical evaluation of force-sensitive probe in the examination of tooth sensitivity]

Two methods were tested for measuring the sensitivity of dentin to mechanical (force-sensitive probe) and cold air stimuli. Of the 212 sensitive teeth in 71 patients, 94.8% were sensitive to probe, with a mean threshold of 22.79g; 89.6% were sensitive to cold air. These two methods were significantly correlated (P < 0.001). The occlusal sites were less sensitive than the buccal sites measured by probe and cold air. It suggests that force-sensitive probe is a simple, quantitative method of measuring tooth hypersensitivity.

Induction by lipopolysaccharide of cyclooxygenase-2 mRNA in rat brain; its possible role in the febrile response

Cyclooxygenase 2 (COX-2) is a newly discovered isoform of cyclooxygenase that is inducible by lipopolysaccharide (LPS) or cytokines. This enzyme is considered to play a major role in inflammatory processes by catalyzing the production of prostaglandins. In the present study, induction of COX-2 mRNA in the rat brain by intraperitoneal injection of LPS was studied by the in situ hybridization technique with special attention paid to timing and sites of induction along with the time course of fever. In situ hybridization was carried out on sections of rat brain, 1 h (latent phase), 2.5 h (maximally febrile phase), 4 h (plateau phase), and 7 h (recovery phase) after the LPS injection, as well as on those from the brains of untreated and saline-injected rats. Injection of LPS induced COX-2 mRNA in the brain in two different constituents: neuronal cells and non-parenchymal cells of the blood vessels and leptomeninges. Induction in the neuronal cells was restricted to some telencephalic areas where the COX-2 mRNA signal was also detected in control animals. The signal was maximally enhanced by 50 to 80% over the basal level 1 h after LPS injection. The COX-2 mRNA signal was hardly detectable in neuronal and glial cells in other brain regions, including the preoptic area, either in control or LPS-injected rats. Strong COX-2 mRNA signals, however, appeared in the inner surface of blood vessels and the leptomeninges over the entire brain, including the preoptic area and its vicinity. The signals were not detectable in the brains of control rats and were most intense in the brains of rats treated with LPS for 2.5 h or 4 h. These results demonstrate that two major cell groups in the brain, neuronal cells and non-parenchymal cells, are responsible for the enhanced production of prostaglandins after systemic LPS treatment. Considering the site and timing of induction, we propose a possible role for blood vessels and leptomeninges as the source of prostaglandin E2 in the genesis of fever.