Epstein-Barr virus reactivation by persistent apical periodontal pathogens

AIM

To assess whether Epstein-Barr virus (EBV) reactivation is triggered by persistent apical periodontitis-related microbes using in vitro and ex vivo methodologies.

METHODOLOGY

Surgically removed human periapical granulomas (n = 50) and healthy gingival tissues (n = 10) were analysed to determine the presence of EBV and seven persistent apical periodontitis-related microbes. In addition, real-time polymerase chain reaction was used to detect the mRNA expression of BZLF-1, an immediate-early gene of EBV. Expression of latent membrane protein (LMP)-1 and ZEBRA, an early lytic protein of EBV encoded by BZLF-1, was also examined using triple-colour immunofluorescence staining. n-Butyric acid produced by the microbes was quantified, and luciferase assays were performed in association with bacterial lysates. In addition, Daudi cells were cultured with bacterial lysates, and the expression levels of BZLF-1 mRNA and ZEBRA protein were determined.

RESULTS

EBV DNA and BZLF-1 mRNA were detected in 47 out of 50 periapical granulomas, but not in healthy gingival tissues. The EBV DNA copy number and the number of Fusobacterium nucleatum were significantly positively correlated with BZLF-1 expression in periapical granulomas. The number of Prevotella intermedia was slightly correlated with BZLF-1 expression; however, the other microbes were not. CD79a-positive B cells in periapical granulomas, but not those in healthy gingival tissues, expressed both LMP-1 and ZEBRA. n-Butyric acid production was the highest in F. nucleatum and the lowest in P. intermedia. Enterococcus faecalis, Candida albicans and the other tested microbes did not produce n-butyric acid. An F. nucleatum lysate exhibited significantly increased BZLF-1-luciferase activity in the same manner of commercial butyric acid, whereas P. intermedia did not. F. nucleatum also induced the expression of BZLF-1 mRNA and ZEBRA protein by Daudi cells, indicating that EBV reactivation was induced.

CONCLUSION

Among the persistent apical periodontitis-related bacteria that were tested, F. nucleatum most strongly reactivated latent EBV, whereas E. faecalis and C. albicans as well as the other microbes did not.

Porphyromonas endodontalis reactivates latent Epstein-Barr virus

AIM

To determine whether Porphyromonas endodontalis can reactivate latent Epstein-Barr virus (EBV).

METHODOLOGY

The concentrations of short-chain fatty acids (SCFAs) in P. endodontalis culture supernatants were determined using high-performance liquid chromatography. A promoter region of BamHI fragment Z leftward open reading frame 1 (BZLF-1), which is a transcription factor that controls the EBV lytic cycle, was cloned into luciferase expression vectors. Then, the luciferase assay was performed using P. endodontalis culture supernatants. Histone acetylation using Daudi cells treated with P. endodontalis culture supernatants was examined using Western blotting. BZLF-1 mRNA and BamHI fragment Z EB replication activator (ZEBRA) protein were also detected quantitatively using real-time polymerase chain reaction (PCR) and Western blotting. Surgically removed periapical granulomas were examined to detect P. endodontalis, EBV DNA, and BZLF-1 mRNA expression using quantitative real-time PCR. Statistical analysis using Steel tests was performed.

RESULTS

The concentrations of n-butyric acid in P. endodontalis culture supernatants were significantly higher than those of other SCFAs (P = 0.0173). Using B-95-8-221 Luc cells treated with P. endodontalis culture supernatants, the luciferase assay demonstrated that P. endodontalis induced BZLF-1 expression. Hyperacetylation of histones was also observed with the culture supernatants. BZLF-1 mRNA and ZEBRA protein were expressed by Daudi cells in a dose-dependent manner after the treatment with P. endodontalis culture supernatants. P. endodontalis and BZLF-1 in periapical granulomas were also detected. The expression levels of BZLF-1 mRNA were similar to the numbers of P. endodontalis cells in each specimen.

CONCLUSIONS

n-butyric acid produced by P. endodontalis reactivated latent EBV.

A potential role for the silent information regulator 2 homologue 1 (SIRT1) in periapical periodontitis

AIM

To investigate the role played by silent information regulator 2 homologue 1 (SIRT1) during angiogenesis of periapical periodontitis.

METHODOLOGY

Periapical granulomas were subjected to dual-colour immunofluorescence imaging and real-time polymerase chain reactions assaying the expression levels of SIRT1, vascular endothelial growth factor (VEGF) and VE-cadherin. The association between Ki-67 and SIRT1 expression was also examined. Human umbilical vein endothelial cells (HUVECs) were treated with a combination of lipopolysaccharide and resveratrol (a SIRT1 activator) or sirtinol (a SIRT1 inhibitor); and the levels of mRNAs encoding SIRT1, VEGF and VE-cadherin were determined. HUVEC tube formation was assayed in the presence of resveratrol or sirtinol. The Mann-Whitney U-test or the Tukey-Kramer test was used for statistical analysis.

RESULTS

Ki-67-expressing cells, including endothelial cells, lay adjacent to SIRT1-expressing cells in periapical granulomas. In addition, SIRT1-expressing cells were detected adjacent to VEGF-expressing cells and VEGF- or VE-cadherin-expressing endothelial cells. SIRT1, VEGF and VE-cadherin mRNA expression levels in periapical granulomas were significantly higher (P = 0.0054, 0.0090 and 0.0090, respectively) than those in healthy gingival tissues. HUVECs treated with resveratrol exhibited significantly higher expression of mRNAs encoding SIRT1, VEGF and VE-cadherin (P = 0.0019, 0.00005 and 0.0045, respectively) compared with controls, but sirtinol inhibited such expression. Resveratrol caused HUVECs to form tube-like structures, whilst sirtinol inhibited this process.

CONCLUSIONS

These findings suggest that SIRT1 may stimulate angiogenesis in periapical granulomas by triggering the proliferation of endothelial cells and inducing VEGF and VE-cadherin expression.

Use of digital subtraction fluoroscopy to diagnose radiolucent aspirated foreign bodies in infants and children

OBJECTIVES

Most tracheobronchial foreign bodies in children are radiolucent, and accurate diagnosis of such foreign bodies is not always easy. This can result in delay of diagnosis or misdiagnosis of foreign body aspiration. We report the usefulness and pitfalls of use of digital subtraction fluoroscopy (DSF) to diagnose radiolucent aspirated foreign bodies in infants.

METHODS

From 1991 through 1999, DSF was conducted for a total of 19 patients (ranged from 11 months to 4 years and 7 months in age (mean 1.8+/-0.9 years)) who were suspected to have radiolucent aspirated foreign bodies. Since DSF revealed abnormal findings in a trachea or main bronchus in 18 cases, inspection was performed for foreign body bronchofiberscopically. In the one remaining case, no abnormality was recognized on DSF, but since the symptoms at the time of onset strongly suggested aspirated foreign body, bronchofiberscopy was also performed.

RESULTS

Foreign body was verified bronchoscopically in 13 of 19 cases, and all 13 (100%) had abnormal findings on DSF, including obstruction of the trachea in two, obstruction of the bronchial lumen in nine, and indistinct visualization of the bronchial lumen in two. Bronchial stenosis was verified bronchoscopically in five of the remaining six cases, including mucus plug in three, granuloma in one and mucosal edema in one case. All five patients (100%) had abnormal findings on DSF, including obstruction of the bronchial lumen in four and indistinct visualization of the bronchial lumen in one. In the one remaining patient with normal findings of DSF, no foreign body or pathological bronchial changes were noted.

CONCLUSIONS

DSF was very sensitive in the diagnosis of foreign body aspiration and stenotic changes in the bronchial lumen. However, its diagnostic specificity for aspirated foreign body itself was not high (17%). Therefore, when abnormalities are found on DSF, we recommend to perform flexible bronchofiberscopy initially under general anesthesia via a tracheal tube. When a foreign body is verified, rigid ventilation bronchoscopy is successively performed to retrieve the foreign body.

Intravenous leiomyomatosis

We present two cases of intravenous leiomyomatosis with uterine leiomyoma or previous hysterectomy because of uterine leiomyoma in which MRI was characteristic. MRI showed a mass in the inferior vena cava and the heart. These MR findings are useful in diagnosing intravenous leiomyomatosis.

Nasopharyngeal colonization with Haemophilus influenzae type b among infants and children in Japan

Healthy carriers of Haemophilus influenzae type b (Hib) play an important role in the spread of invasive Hib disease. The aim of the present study was to estimate Hib colonization among infants and children in Japan. Specimens from throat and nasopharyngeal cultures were obtained by thorough swabbing of both tonsils and the posterior pharynx. Specimens were inoculated on Hib antiserum agar. This was prepared with Levinthal base and Hib antiserum. Conventional methods were used concomitantly. Four of 474 infants from 1-48 months of age (0.84%) had Hib cultured from their nasopharynx. The carriage rate in 1-12 months old infants was 0.62% (2/322 cases), and that in 13-48 month old children was 1.32% (2/152 cases). Five of 167 (3.0%) 13-year-old children, and five of 154 (3.2%) 9-year-old children were asymptomatic carriers. Thirty-five of 104 household contacts of a patient with invasive Hib disease (33.6%) had Hib colonization. The carriage rate in healthy Japanese children may not be different from that in the USA prior to the availability of the conjugate Hib vaccine. The Hib carriage rate in household contacts of patients with invasive Hib disease was higher than in healthy children (P < 0.005). Our results suggest the possibility of an outbreak of invasive Hib disease in Japan.

Continuous monitoring of jugular bulb oxygen saturation as a measure of the shunt flow of cerebral arteriovenous malformations

Jugular bulb oxygen saturation (SjO2) was monitored during preoperative embolization procedures in a consecutive series of 15 patients with large supratentorial arteriovenous malformations (AVM's) in order to test the hypothesis that changes in the shunt flow ratio can be continuously evaluated from the SjO2. A fiberoptic catheter was placed at the dominant jugular bulb. The SjO2 measured using jugular blood withdrawn before embolization was significantly higher than the SjO2 measured at the end of the final embolization procedure (mean +/- standard deviation 84.1% +/- 12.7% vs. 74.2% +/- 10.9%, p < 0.0001), showing a positive correlation with the AVM volume (r = 0.66, p < 0.001). Continuous monitoring of SjO2 via the fiberoptic catheter revealed a progressive decrease in association with the embolization procedures. Microsurgical resection of the AVM was performed at 1 to 2 weeks after the final embolization. Cases in which postoperative hemispheric deformation was revealed on computerized tomography demonstrated a higher SjO2 at the end of embolization compared to that in the remaining cases (81.6% +/- 8.6% vs. 67.8% +/- 8.4%, p < 0.008). Hemispheric deformation was observed in all cases in which the SjO2 did not decline to a level below 90% following embolization. The risk of severe hyperemic complications appeared to be greatly diminished when the SjO2 fell to below 80%. Assuming that the oxygen saturation of the perfusion flow (SjpO2) ranges from 50% to 75%, the ratio of the shunt flow to total flow at an SjO2 of 90% was estimated to be 0.6 to 0.8 based on the following equation: shunt flow/(perfusion flow + shunt flow) = (SjO2 - SjpO2)/(arterial oxygen saturation - SjpO2). These results suggest that monitoring the SjO2 provides real-time information concerning the progress of embolization and helps to determine whether the embolization has progressed sufficiently to avoid postoperative hyperemic complications.

Growth of a giant aneurysm following complete thrombosis by detachable balloon occlusion

A giant basilar artery aneurysm demonstrating growth and causing neurological deterioration even after complete detachable balloon occlusion is reported. Autopsy revealed total thrombosis of the aneurysm and a hemiconcentric, onion skin-like, laminated structure. Numerous vascular channels and multiple fresh intramural hemorrhages were noted within the outer margin of the aneurysmal wall. Repeated intramural hemorrhages appeared to have been responsible for the aneurysmal laminated structure and contributed to progressive aneurysmal growth. This case demonstrates that the growth of some giant aneurysms is not dependent upon the continuity with the parent artery, and progressive enlargement cannot always be prevented by balloon occlusion.

[Effects of contrast media under systemic heparinization on blood coagulation and fibrinolytic system during angiocardiography--comparison of ionic and nonionic contrast media]

Nonionic contrast media are suggested to cause increased thromboembolism (in vivo), because of less inhibitory action on blood coagulation and platelet aggregation (in vitro) as compared with ionic contrast media. Therefore, to prevent thrombotic complication, we examined whether differences in blood coagulation and fibrinolytic system between the two groups received nonionic (iopamidol) and ionic (ioxaglate) contrast media are seen in vivo when 2,500 unit heparin is administered during angiocardiography. 20 patients undergoing routine angiocardiography were randomized to two groups of 10 patients each. Blood heparin concentration, activated partial thromboplastin time, prothrombin time, thrombin-antithrombin III complex (TAT), antithrombin III, fibrinogen, alpha 2-plasmin inhibitor plasmin complex, fibrinogen and fibrin degradation product were measured at four stages during the procedure: before and 5 min after 2,500 unit bolus heparin administration, 5 min after left ventriculography, and at the end of procedure. Systemic heparinization inhibited clot formation in the presence of nonionic contrast media. TAT generations were elevated before heparinization, after heparinization, however these generations were remarkably inhibited in both groups. No remarkable differences were noted at 40 +/- 14 min duration of procedure when these parameters were compared between the two groups. Since nonionic contrast media did not activate blood coagulation and fibrinolytic system with 2,500 unit heparin administration as compared with ionic contrast media, systemic heparinization was demonstrated to be effective in the prevention of thrombotic complication.

[Effects of uro-angiographic contrast media on blood coagulation--a scanning electron microscopic study on time dependent changes of blood clot and a clinical study]

Anticoagulant activity of ionic and nonionic contrast media (CM) was investigated in vitro and in vivo. Based on the time course of FPA and TAT generations and gross examinations of the blood clots on the catheters placed in CM-blood mixtures [an 2 to 8 ratio (20% v/v)]. It was demonstrated that blood coagulation was activated during the period of 20 to 30 minutes when nonionic CM (iopamidol, iohexol) was employed, but no activation of blood coagulation was noted with ionic CM (diatrizoate, ioxaglate). Scanning electron microscopic examinations of the clots on the catheters revealed that fine fibrin meshwork fibers, in which many red blood cells were trapped in bound, were observed with nonionic CM. In contrast, no fibrin mesh was formed with ionic CM after 30 minutes. In vivo, antithrombin III and fibrinogen significantly decreased in the patients who underwent infusion of nonionic CM. Our studies confirmed that nonionic CM show weaker anticoagulant activity than do ionic CM. And these findings account for previous reported thromboembolic complications with the use of nonionic CM. Extreme caution should be therefore exercised when nonionic CM are employed during prolonged angiographic and interventional procedures.

Intraparenchymal blood-fluid levels in traumatic intracerebral haematomas

Blood-fluid levels within the cerebral parenchyma are observed more frequently on CT and MRI in traumatic intracerebral haematomas than in those of other aetiologies. The intraparenchymal blood-fluid interface can be formed without a fluid cavity. It is suggested that the blood-fluid levels represent layering of red blood cells within areas of contusion necrosis as well as extensive contusion oedema. The more extensive the damage to brain tissue, the more often blood-fluid levels formed. A poorer outcome can be therefore predicted when an intraparenchymal blood-fluid interface is seen.

Embolization of intramedullary spinal arteriovenous malformation fed by the anterior spinal artery with monitoring of the corticospinal motor evoked potential--case report

Intramedullary spina AVMs fed by the anterior spinal artery cannot be embolized without risking unacceptable motor deficits, since the feeding arteries may supply the corticospinal tract (CST). An 8-year-old boy underwent successful embolization of such an AVM under general anesthesia using intermittent infusion of embolic material with monitoring of the CST integrity with the corticospinal motor evoked potential (MEP). This case illustrates the value of corticospinal MEP monitoring during therapeutic procedures under general anesthesia which risk interrupting the blood supply to the CST.

Growth of totally thrombosed giant aneurysm within the posterior cranial fossa. Diagnostic and therapeutic considerations

We report a case in which growth of a totally thrombosed giant aneurysm of the posterior cranial fossa was demonstrated by computed tomography (CT) scans repeated after 4 years. A magnetic resonance (MR) image demonstrated an onion-skin-like, laminated structure within a calcified wall. The laminated structure had developed around an old thrombosis, without any communication to the flowing blood. It showed intensities indicating recent clots, revealing that the giant aneurysm had grown by recurrent intramural hemorrhage rather than by intraluminal accumulation of thrombotic materials. This case illustrates that totally thrombosed giant aneurysms still have the potential of growth.

Magnetic resonance imaging of cavernous sinus cavernous hemangiomas

Radiological findings of surgically verified cavernous hemangiomas of the cavernous sinus are presented with special reference to the appearance in magnetic resonance imaging. Differences in radiological features of the cavernous sinus cavernous hemangiomas and intracerebral cavernous hemangiomas are discussed.

[Preliminary study and clinical evaluation method of ioversol in angiocardiography--establishment of safety evaluation parameters and reliability of radiographic quality evaluation]

A multi-center clinical study of a new nonionic iodinated contrast medium (ioversol) was performed in 26 patients undergoing left ventriculography (LVG) and coronary angiography (CAG) at four centers. The aims of this study were to try to establish a clinical evaluation method on contrast media in angiocardiography and to determine radiographic efficacy and safety of ioversol. The reliability of the method evaluating the radiographic quality of the contrast medium was also examined with statistical analysis. Excellent radiographic efficacy was observed with ioversol and morphological diagnosis was possible in all cases. The electrocardiograms (ST-segment deflection, T-wave amplitude, QT interval, corrected QT interval, arrhythmia and heart rate) and the hemodynamic parameters (left ventricular systolic and end diastolic pressures, left ventricular dp/dt max, aortic systolic and diastolic pressures) indicated no clinically significant changes. This study suggested that the monitoring of the ECGs and hemodynamic parameters for up to three minutes after injection of the contrast medium is sufficient for the evaluation in LVG and CAG, and that the monitoring in CAG during the first injection into each left and right coronary artery is also sufficient for the purpose. Heat sensation during injection was mild. A patient had a symptom of nausea after ioversol administration, but it was mild and transient and resolved spontaneously. There were no abnormal clinical laboratory data related to ioversol. The reliability of the radiographic quality evaluated by the individual clinical investigators was considered to be high and adaptable. However, the evaluation in the blinded cinefilms by the committee members involving all investigators would be more preferable for the higher objectivity. The study results suggest that ioversol is considered to be the efficacious and safe contrast medium for the cardiovascular angiography.

[A case of penicillin-resistant pneumococcal meningitis and antibiotic susceptibility of Streptococcus pneumoniae isolated from children]

Recently, isolation of penicillin-resistant S. pneumoniae has been increasing. The first Japanese case of penicillin-resistant pneumococcal meningitis was reported in 1988. We experienced a case of a one-year-old boy with penicillin-resistant pneumococcal meningitis who dead on arrival on his third day of illness. Minimal inhibitory concentration (MIC) of penicillin G or S. pneumoniae isolated from cerebrospinal fluid and blood was 0.6 micrograms/ml. We evaluated the antibiotic susceptibility of 163 strains of S. pneumoniae isolated from children from 1985 to 1988. Penicillin G (PCG), ampicillin (ABPC), cefotaxime (CTX), imipenem (IPM), and vancomycin (VCM) had good susceptibilities to S. pneumoniae. Twelve of the 163 isolates (7.3%) were penicillin-resistant strains whose MIC of PCG were more than 0.1 microgram/ml, and all of them were intermediately resistant. The annual penicillin-resistant rates were 12.5% in 1985, 1.3% in 1986, 0% in 1986, and 19.0% in 1988. We also evaluated the MIC distribution and MIC90 of antibiotics available for meningitis against penicillin-sensitive and -resistant S. pneumoniae. MIC90 of PCG and ABPC against penicillin-resistant strains was 1.56 micrograms/ml, and it might be dangerous to use PCG or ABPC for central nervous system pneumococcal infections. MIC90 of IPM against penicillin-resistant strains was 0.1 microgram/ml, and that of VCM was 0.4 micrograms/ml. There was little fall of susceptibilities of resistant strains in IPM and VCM. We evaluated the MIC distribution and MIC70 of antibiotics for oral usage against penicillin-sensitive and -resistant S. pneumoniae. Although there were falls of susceptibilities of resistant strains in PCG and ABPC, these two antibiotics had the best susceptibilities among the oral antibiotics.

[Clinical studies of sulbactam/cefoperazone therapy in pediatric bacterial infections]

Sulbactam/cefoperazone (SBT/CPZ) was administered intravenously to 9 patients with respiratory infections (H. influenzae 6 cases, pathogens unknown 3 cases), 2 patients with urinary tract infection (E. coli and C. freundii; both cases had VUR), and 1 patient with staphylococcal bacteremia. In these causative bacteria, 5 strains (H. influenzae 3, E. coli 1 and S. aureus 1) were beta-lactamase producers. Bacteriological efficacy (eradication rate) was complete (9/9, 100%) and clinical efficacy was also complete (12/12, 100%). In comparison with CPZ alone, MICs of SBT/CPZ against beta-lactamase producing bacteria were superior. Although mild side effect was observed in 1 case (eosinophilia), no other severe form of adverse reaction were encountered. It was concluded that SBT/CPZ was an useful antibiotic for the treatment of pediatric bacterial infections, especially caused by beta-lactamase (penicillinase) producing bacteria.

[Fundamental and clinical studies of ceftazidime in the field of pediatrics]

We have studied ceftazidime (CAZ), a cephem antibiotic of the new generation, for its antibacterial activity against H. influenzae and clinical effects. Antibacterial activity: MICs of CAZ for 142 strains of H. influenzae including 11 ABPC-resistant strains which were clinically isolated, were determined, and the results were good for all the strains. Clinical effects: CAZ was administered to 9 children with infections. Suspected causative organisms were H. influenzae, E. coli, P. aeruginosa, group B Streptococcus and S. pneumoniae. Eradication of these organisms was confirmed in all the strains except for one in which the antibacterial effect of CAZ was unknown. Clinical efficacy was excellent or good in all the cases. No side effect was observed except for eosinophilia noted in 1 case.

[Clinical evaluation of cefpiramide in 6 cases of infection in children]

Cefpiramide (CPM) was given to 4 patients with respiratory tract infection (H. influenzae 3 cases, P. aeruginosa 1 case), 1 patient with enteritis (enteropathogenic E. coli) and 1 patient with sepsis (E. cloacae). Bacteriological eradication was observed in 5 cases (83.3%), and clinical effectiveness was 66.7%. Serum concentration of CPM at a dose of 15 mg/kg after intravenous drip-infusion for 30 minutes was 105 micrograms/ml at the end of infusion and 67 micrograms/ml at 1 hour. Bacteriological eradication by the administration of CPM was rapidly occurred in 3 strains of H. influenzae including 1 strain of beta-lactamase producing ABPC-resistant one, and 1 strain of P. aeruginosa in the sputum. One patient aged 2 years and 5 months with pneumonia was cured by the treatment of CPM as an outpatient. No side effects were observed except 1 case of vascular pain. It was concluded that CPM is a useful drug for the treatment of bacterial infections in children.