Scavenging property of three cresol isomers against H2O2, hypochlorite, superoxide and hydroxyl radicals

Formocresol has long been used for pulpotomy of primary teeth and as an intracanal medicament. Little is known, however, about the pharmacological effect of tricresols. This study showed that three cresol isomers, o-cresol, m-cresol and p-cresol, are H2O2 scavengers with a 50% inhibitory concentration (IC50) of 502, 6.7 and 10.16 microM, respectively. o-, m- and p-cresol were also shown to be effective scavengers of superoxide radicals generated by xanthine/xanthine oxidase with an IC50 of 282, 153 and > 4000 microM, respectively, as analyzed by luminometer. o-, m- and p-cresol showed protective effects on the DNA breaks generated by H2O2/FeCl2 and FeCl3/ascorbate/H2O2 systems at concentrations ranging from 70 microM to 1.43 mM, o-, m- and p-cresol also showed differential protective effects against DNA breaks induced by 0.17% NaOCl with 100% inhibitory concentration (IC100) of about 10, 1 and 10 mM, respectively. In addition, reaction with 3% H2O2 and 0.17% NaOCl completely prevented NaOCl-induced DNA breaks. The results indicate that the three cresol isomers are effective ROS scavengers and may prevent ROS induced damage when used as pulpotomy agents or as intracanal medicaments. Owing to the difference in the position of the functional hydroxyl group in the three cresol isomers, m-cresol is the most effective ROS scavenger. Concomitant use of H2O2 for root canal irrigation may diminish both the tissue dissolving capacity of NaOCl and NaOCl-induced DNA damage.

An in vitro study on restoring bond strength of a GIC to saliva contaminated enamel under unrinse condition

OBJECTIVES

This study attempted to find a method of restoring the tensile bond strength of glass ionomer cement (GIC) to saliva contaminated enamel under unrinse condition.

METHODS

One hundred and thirty human non-carious permanent teeth were divided into two major groups. Either treatment with air drying, acetone, polyacrylic acid, maleic acid, tartaric acid, Scotchbond primer or no treatment at all was applied to both clean and saliva contaminated enamel surfaces prior to GIC placement. Samples were debonded in tension after 7 days of storage in water using a universal testing machine. Statistical analysis was performed using one-way ANOVA, Tukey's studentized range test and Wilcoxon's rank sums test to determine the significance of the difference of tensile bond strengths within and between the two major groups.

RESULTS

Bond strength of GIC to clean enamel was 2.46+/-0.79 MPa while the bond strength of GIC to wet contaminated enamel was significantly reduced to 1.28+/-0.32 MPa (p<0.01). However, the bond strengths were restored when the contaminated enamel surfaces were air-dried (2.19+/-0.38 MPa) or applied with either maleic acid (2.80+/-0.63 MPa) or Scotchbond primer (2.13+/-0.65 MPa) before placing GIC over the enamels.

CONCLUSIONS

Air drying, or application of maleic acid or Scotchbond primer to the contaminated enamel without rinsing prior to GIC placement can restore the tensile bond strength to a level similar to that of non-contaminated control.

Transoesophageal echocardiographic monitoring of pulmonary venous obstruction induced by sternotomy closure during infant heart transplantation

A case of an infant receiving orthotopic heart transplantation with over-sized donor heart was reported. Left lower pulmonary venous obstruction after sternotomy closure was detected by transoesophageal echocardiography (TOE) and the decision to delay sternal closure was made and the clinical outcome was very satisfactory. The usefulness of intraoperative TOE monitoring and postoperative TOE follow-up for infant heart transplantation, especially in those cases of size mismatch, was well demonstrated.

Validation of diffusion tensor magnetic resonance axonal fiber imaging with registered manganese-enhanced optic tracts

Noninvasive mapping of white matter tracts using diffusion tensor magnetic resonance imaging (DTMRI) is potentially useful in revealing anatomical connectivity in the human brain. However, a gold standard for validating DTMRI in defining axonal fiber orientation is still lacking. This study presents the first validation of the principal eigenvector of the diffusion tensor in defining axonal fiber orientation by superimposing DTMRI with manganese-enhanced MRI of optic tracts. A rat model was developed in which optic tracts were enhanced by manganese ions. Manganese ion (Mn(2+)) is a potent T1-shortening agent and can be uptaken and transported actively along the axon. Based on this property, we obtained enhanced optic tracts with a T1-weighted spin-echo sequence 10 h after intravitreal injection of Mn(2+). The images were compared with DTMRI acquired with exact spatial registration. Deviation angles between tangential vectors of the enhanced tracts and the principal eigenvectors of the diffusion tensor were then computed pixel by pixel. We found that under signal-to-noise (SNR) of 30, the variance of deviation angles was (13.27 degrees). In addition, the dependence of this variance on SNR obeys stochastic behavior if SNR is greater than 10. Based on this relation, we estimated that an rms deviation of less than 10 degrees could be achieved with DTMRI when SNR is 40 or greater. In conclusion, our method bypasses technical difficulties in conventional histological approach and provides an in vivo gold standard for validating DTMRI in mapping white matter tracts.

Petal-like apatite formed on the surface of tricalcium phosphate ceramic after soaking in distilled water

In the present study six types of tricalcium phosphate ceramic were prepared and soaked in distilled water for different periods to investigate whether a surface apatite layer was formed on TCP ceramics or not. X-ray diffractometry (XRD) and Fourier-transformed infrared (FTIR) spectrometer were used to examine the changes in crystalline phases and functional groups of TCP ceramics for different soaking periods. Calcium and phosphate ions released from TCP ceramics during soaking were recorded by atomic absorption analysis and ion-coupled plasma. Results revealed that alphaTCP, alphaTCP/betaTCP mixture (alphabetaTCP) and betaTCP ceramic were gradually dissolved. There was no apatite layer formed on their surface after being immersed in distilled water for different durations of time. Mg-TCP ceramic, tricalcium phosphate doped with Mg ions, exhibited a lower dissolution rate than the other types of TCP ceramics. Apatite crystals were also not formed on the surface of Mg-TCP ceramic when immersed in distilled water. Tribasic calcium phosphate, prepared from wet precipitation method, was converted to betaTCP/HAP (HbetaTCP) or alphaTCP/betaTCP/HAP (HalphabetaTCP) crystalline composition at different sintering temperatures (1,150 degrees C and 1,300 degrees C). The surface apatite layer did not appear on HbetaTCP ceramic after soaking. We observed that petal-like apatite was formed on the HalphabetaTCP ceramic surface after being immersed for 2 weeks. alphaTCP phase of HalphabetaTCP ceramic was not directly converted to apatite during soaking. The surface apatite layer formed on the HalphabetaTCP ceramic surface was due to the precipitation of the calcium and phosphate ions released from alphaTCP dissolution. HAP, which existed in the structure of HalphabetaTCP ceramic, plays a role as apatite-precipitating seed to uptake calcium and phosphate ions. TCP ceramics which lacked alphaTCP and HAP content neither converted to apatite nor formed surface apatite on their surfaces during immersion.

Sequential changes of gastric hyperplastic polyps following endoscopic ligation

BACKGROUND

Endoscopic ligation has been extensively applied in the management of esophageal and gastric varices with or without bleeding. The varices are automatically eradicated through the use of ligation. However, whether avascular necrosis will occur in a gastrointestinal polyp when the base is ligated remains unclear. The aims of this pilot study were to investigate the sequential changes of gastric hyperplastic polyps following endoscopic detachable snare ligation and to determine the possibility of induction of avascular necrosis in these lesions following ligation.

METHODS

Eleven patients with eighteen gastric hyperplastic polyps were treated with endoscopic detachable-snare ligation. The polyps were observed for 5 minutes and biopsies were then conducted. At 14 days after endoscopic ligation, follow-up endoscopies were performed to assess the outcome of the strangulated polyps.

RESULTS

After being strangulated by the detachable snares, a majority of the polyps immediately congested (94%), and then developed cyanotic change (89%) approximately 4 minutes later. Pathological examination revealed severe venous congestion in the lamina propria of the strangulated polyps. On follow-up endoscopy 2 weeks later, all the snares had dropped off, and avascular necrosis occurred in sixteen polyps (89%). All of the polyps with avascular necrosis were detected to have developed cyanotic changes in initial endoscopy. No complications occurred during or following the ligation procedure.

CONCLUSIONS

Most gastric hyperplastic polyps develop avascular necrosis following ligation by detachable snare. Cyanotic change is an important predictor of the outcomes of the lesions following endoscopic ligation. The application of this ligation technique in treatment of bleeding or non-bleeding gastrointestinal polyps deserves further investigation.

Induction of cellular toxicity in cultured porcine corneal keratocytes by endothelin-1

The effect of endothelin-1 (ET-1) on corneal cells is not well understood. We investigated the biochemical changes of cultured porcine corneal keratocytes under exposure to ET-1. The results indicate that ET-1 has remarkable effects to inhibit corneal keratocytes on 3H-thymidine, 3H-leucine, 3H-uridine uptakes and cellular migration. It is in a dose-dependent manner at concentrations ranging from 10(-7) M to 10(-9) M. The 50% inhibitory dose (ID50) for ET-1, as measured by 3H-thymidine uptake, 3H-uridine uptake and 3H-leucine uptake, were 10(-7) M, 10(-0.52) M and 10(-11.8) M, respectively. The dead and living cells were estimated with MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide) assay that was converted tetrazolium dye of living cells only into insoluble purple formazan crystals within mitochondria. In the presence of ET-1, the cellular MTT values were also decreased. The ID50 for ET-1 with cell migration assay and MTT assay were measured at 10(-7.86) M and 10(-5.1) M. Endothelin-1 (10(-6) M) promptly changed cellular morphology and attenuated adhesion observed with laser scanning cytometer. Endothelin-1-induced characteristic apoptosis cells were observed using a TUNEL assay that detected fragmented DNA of apoptosis. Western blot assay revealed that endothelin-1 induced proteolysis and decreased in fibronectin protein. These findings indicate that endothelin-1 may lead keratocytes to death resulting from induction of apoptosis and functional loss.

Laser-beam-triggered microcavitation: a novel method for selective cell destruction

We describe a new method of cell destruction that may have potential for use in antitumor therapy. Cells are loaded by phagocytosis with microparticles (<1 microm) and irradiated with short laser pulses. Absorption of laser energy by the microparticles causes localized vaporization of the fluid surrounding the microparticles, leading to the generation of transient vapor bubbles (microcavitation) around the microparticles. Using cultures of bovine aortic endothelial cells, we demonstrate that induction of intralysosomal microcavitation is an efficient, rapid and selective method of cell killing that is dependent on the number of microparticles, the number of laser pulses, and the fluence of the laser pulses. Cell killing by microcavitation is a very selective process that is restricted to cells containing microparticles, leaving other cells unaffected. Intracytoplasmic release of lysosomal hydrolases is, in part, responsible for cell death, because the protease inhibitors E64d and TLCK diminished cell killing. Using the broad-specificity caspase inhibitor Z-VAD-fmk, we determined that lysosomal hydrolases could induce apoptosis in a caspase-independent manner. We also examined the possibility of microcavitation-induced delayed effects in the cells that survived the treatment. Using flow cytometry, we determined that there was no delayed cell death between 1 and 4 days after microcavitation. Moreover, we did not observe changes in the cell cycle, in expression of the proteins BCL2, HSP70 and HSP27, or in PARP degradation. In conclusion, microcavitation induces rapid and specific cells death (limited only to cells containing microparticles), without producing delayed effects among the surviving cells.

Endothelin-induced changes of secondary messengers in cultured corneal endothelial cells

The effect of endothelins on corneal endothelial cells is not well understood. We have investigated the effects of endothelin-1 (ET-1), endothelin-2 (ET-2) and endothelin-3 (ET-3) on bovine corneal endothelial cellular proliferation and the secondary messenger changes in cells in the presence of ET-1. It was found that the 3H-thymidine uptake was enhanced by ET-1 significantly, whereas ET-2 and ET-3 had no effect. ET-1 remarkably affects the increase of corneal endothelial cells on 3H-thymidine, 3H-leucine, and 3H-uridine uptakes in a dose-dependent manner. The 50% effective concentrations (EC50) for ET-1, as measured by 3H-thymidine uptake, 3H-uridine uptake, and 3H-leucine uptake were 10(-8.78) M, 10(-8.53) M and 10(-8.04) M, respectively. It was found that endothelin-1 increased intracellular calcium concentration by using the method of preloading with Fura-2-AM and assaying with spectrophotometry. The cellular IP1, IP2, and IP3 were also stimulated in the presence of ET-1. Moreover, ET-1 enhanced the basal cellular cAMP and cGMP concentrations in corneal endothelial cells in a dose-dependent manner. Immunofluorescent staining revealed that ET-1 increased the fibronectin protein concentration and changed protein distribution in corneal endothelial cells. These findings indicate that endothelin-1 increases in cell proliferation and biological changes may be involved in changing intracellular calcium mobility, increasing intracellular phosphoinositides, enhancing intracellular cGMP and cAMP accumulation, and fibronectin protein synthesis.

Phase, compositional, and morphological changes of human dentin after Nd:YAG laser treatment

Although techniques for repairing root fracture have been proposed, the prognosis is generally poor. If the fusion of a root fracture by laser is possible, it will offer an alternative to extraction. Our group has attempted to use lasers to fuse a low melting-point bioactive glass to fractured dentin. This report is focused on the phase, compositional, and morphological changes observed by means of X-ray diffractometer, Fourier transforming infrared spectroscopy, and scanning electron microscopy-energy dispersive X-ray spectroscopy in human dentin after exposure to Nd:YAG laser. The irradiation energies were from 150 mJ/ pulse-10 pps-4 s to 150 mJ/pulse-30 pps-4 s. After exposure to Nd:YAG laser, dentin showed four peaks on the X-ray diffractometer that corresponding to a-tricalcium phosphate (TCP) and beta-TCP at 20 = 30.78 degrees/34.21 degrees and 32.47 degrees/33.05 degrees, respectively. The peaks of a-TCP and beta-TCP gradually increased in intensity with the elevation of irradiation energy. In Fourier transforming infrared analysis, two absorption bands at 2200 cm(-1) and 2015 cm(-1) could be traced on dentin treated by Nd:YAG laser with the irradiation energies beyond 150 mJ/pulse-10 pps-4 s. The energy dispersive X-ray results showed that the calcium/phosphorus ratios of the irradiated area proportionally increased with the elevation of irradiation energy. The laser energies of 150 mJ/ pulse-30 pps-4 s and 150 mJ/pulse-20 pps-4 s could result in the a-TCP formation and collagen breakdown. However, the formation of glass-like melted substances without a-TCP at the irradiated site was induced by the energy output of 150 mJ/ pulse-10 pps-4 s. Scanning electron micrographs also revealed that the laser energy of 150 mJ/ pulse-10 pps-4 s was sufficient to prompt melting and recrystallization of dentin crystals without cracking. Therefore, we suggest that the irradiation energy of Nd:YAG laser used to fuse a low melting-point bioactive glass to dentin is 150 mJ/ pulse-10 pps-4 s.

Dihydropyridine calcium channel blockers inhibit ascorbic acid accumulation in human intestinal Caco-2 cells

We investigated the effect of commonly used medications on the accumulation of ascorbic acid in human intestinal Caco-2 cells. Although ascorbic acid is negatively charged at physiological pH, anionic compounds including drugs and metabolites had little effect on its accumulation. On the other hand, hydrophobic 1,4-dihydropyridine compounds (nifedipine and nicardipine), but not other structurally unrelated calcium channel blockers, were found to be potent inhibitors. They inhibited both Na+-dependent and Na+-independent (K+ substituting Na+) accumulation of ascorbic acid. The inhibition was non-competitive with a Ki of 108 microM and 9 microM for nifedipine and nicardipine, respectively. The efflux of ascorbic acid from cells was not affected. Previously, we reported a similar inhibition of ascorbic acid accumulation by estrogens. When nifedipine and estrogens were included in the buffer together, the combined inhibitory effect was less than additive implying that they may act through the same mechanism. The potential clinical significance of dihydropyridine usage on ascorbic acid status in human needs to be considered.

Treatment of tooth fracture by medium-energy CO2 laser and DP-bioactive glass paste: the interaction of enamel and DP-bioactive glass paste during irradiation by CO2 laser

Acute trauma or trauma associated with occlusal disturbance can produce tooth crack or fracture. Although several methods are proposed to treat the defect, however, the prognosis is generally poor. If the fusion of a tooth fracture by laser is possible, it will offer an alternative to extraction or at least serve as an adjunctive treatment in the reconstruction. We have tried to use a continuous-wave CO2 laser and a newly developed DP-bioactive glass paste (DPGP) to fuse or bridge tooth crack or fracture lines. Both the DP-bioactive glass paste and tooth enamel have strong absorption bands at the wavelength of 10.6 microm. Therefore, under CO2 laser, DPGP and enamel should have an effective absorption and melt together. The interface between DPGP and enamel could be regarded as a mixture of DPGP and enamel (DPG-E). The study focused on the phase transformation, microstructure, functional group and thermal behavior of DPG-E with or without CO2 laser irradiation, by the analytical techniques of XRD, FTIR, DTA/TGA, and SEM. The results of XRD showed that the main crystal phase in the DPG-E was dicalcium phosphate dihydrate (CaHPO4.2H2O). It changed into CaHPO4, gamma-Ca2P2O7, beta-Ca2P2O7 and finally alpha-Ca2P2O7 with increasing temperature. In the FTIR analysis, the 720 cm(-1) absorption band ascribed to the P-O-P linkage in pyrophosphate rose up and the intensities of the OH- bands reduced after laser irradiation. In regard to the results of DTA/TGA after irradiation, the weight loss decreased due to the removal of part of absorption water and crystallization water by the CO2 laser. SEM micrographs revealed that the melted masses and the plate-like crystals formed a tight chemical bond between the enamel and DPGP. We expect that DPGP with the help of CO2 laser can be an alternative to the treatment of tooth crack or fracture.

Comparison of clinical, serological and histological findings between non-ulcer dyspepsia patients with and without Helicobacter pylori infection

BACKGROUND AND AIMS

The role of Helicobacter pylori (H. pylori) infection in non-ulcer dyspepsia (NUD) remains controversial. This study investigates the clinical, serological and histological differences between patients with H. pylori-positive and -negative NUD.

METHODS

One hundred and eighty consecutive patients with NUD were enrolled from January to December 1998. The severity of symptoms was evaluated by the Tucci's scoring system. The histological changes of gastric mucosa were assessed according to the Updated Sydney System, and a fasting blood sample was obtained to test the serum gastrin and pepsinogen I levels.

RESULTS

The H. pylori-positive NUD patients were notably older than H. pylori-negative NUD patients (48.2 +/- 15.9 vs 39.8 +/- 15.7 years, P= 0.001). There were no differences in other clinical factors between the two NUD groups. The serum pepsinogen I levels were considerably higher in H. pylori-positive NUD patients than in H. pylori-negative NUD patients (78.9 +/- 42.2 vs 61.5 +/- 43.3 ng/mL, P<0.01). However, no significant differences in serum gastrin levels were discovered between the two groups. The antrum histological scores for chronic inflammation, acute inflammation, gland atrophy and lymphoid follicles were higher in H. pylori-positive NUD patients than in H. pylori-negative NUD patients (2.09 vs 1.01, P<0.001; 1.22 vs 0.36, P<0.001; 0.76 vs 0.36, P<0.01; 0.33 vs 0.13, P<0.01, respectively).

CONCLUSIONS

The present study discovered marked differences in age, serum pepsinogen I levels, histological grades of acute inflammation, chronic inflammation, gland atrophy and lymphoid tissue formation between H. pylori-positive and H. pylori-negative NUD patients. Further investigation of the clinical prognosis of the two groups of patients is necessary.

Origin of retinal pigment epithelium cell damage by pulsed laser irradiance in the nanosecond to microsecond time regimen

BACKGROUND AND OBJECTIVE

Selective photodamage of the retinal pigment epithelium (RPE) is a new technique to treat a variety of retinal diseases without causing adverse effects to surrounding tissues such as the neural retina including the photoreceptors and the choroid. In this study, the mechanism of cell damage after laser irradiation was investigated.

STUDY DESIGN/MATERIALS AND METHODS

Single porcine RPE-melanosomes and RPE cells were irradiated with a Nd:YLF laser (wavelength lambda = 527 nm, adjustable pulse duration tau = 250 nsec-3 microsec) and a Nd:YAG laser (lambda = 532 nm, tau = 8 nsec). Fast flash photography was applied to observe vaporization at melanosomes in suspension. A fluorescence viability assay was used to probe the cells vitality.

RESULTS

The threshold radiant exposures for vaporization around individual melanosomes and for ED50 cell damage are similar at 8-nsec pulse duration. Both thresholds increase with pulse duration; however, the ED50 cell damage radiant exposure is 40% lower at 3 microsec. Temperature calculations to model the onset of vaporization around the melanosomes are in good agreement with the experimental results when assuming a surface temperature of 150 degrees C to initiate vaporization and a homogeneous melanosome absorption coefficient of 8,000 cm(-1). Increasing the number of pulses delivered to RPE cells at a repetition rate of 500 Hz, the ED50 value decreases for all pulse durations. However, the behavior does not obey scaling laws such as the N 1/4 equation.

CONCLUSION

The origin of RPE cell damage for single pulse irradiation up to pulse durations of 3 microsec can be described by a damage mechanism in which microbubbles around the melanosomes cause a rupture of the cell structure. The threshold radiant exposure for RPE damage decreases with increasing number of pulses applied.

Treatment of dental root fracture by medium energy CO2 laser and DP-bioactive glass paste. Part. II: Compositional, structure, and phase changes of DP-bioglass paste after exposed to CO2 laser

Fractured teeth are difficult to treat effectively. Currently, such as root fractures are usually treated by full-coverage restoration, root amputation, or tooth extraction. If the fusion of tooth fracture by laser were possible, it could offer a different therapy to repair fracture teeth. We tried to use a developed DP-bioactive glass paste to fuse or bridge the tooth crack line by a medium energy continuous-wave CO2 laser. The present report was focused on the phase transformation and rescrystallization of DP-bioactive paste during expose to the CO2 laser. The materials will examine by means of XRD, FTIR, DTA/TGA, and SEM. From the study, we could expect that the temperature increase due to laser irradiation must be over than 900 degrees C and the DP-bioactive glass paste could be melted in a short period of time after irradiation. In the study, we successfully developed a DP-bioactive glass paste which could form a melting glass within minutes after exposed to a medium energy density continuous-wave CO2 laser. The paste will be used to bridge the enamel or dentine surface crack by the continuous-wave CO2 laser in the near future.

Influence of gamma irradiation and storage on apheresis platelets

BACKGROUND AND PURPOSE

Gamma irradiation of platelet concentrates to prevent graft-versus-host disease may inactivate contaminated lymphocytes and subsequently inhibit the synthesis of cytokines in the apheresis platelets during storage. We investigated the influence of irradiation and storage on apheresis platelets collected with the COBE Spectra or Fenwal CS-3000 Plus systems.

METHODS

Eleven units of apheresis platelets were collected with a COBE Spectra cell separator and another 11 units with a Fenwal CS-3000 Plus system. Each unit of apheresis platelets was divided into two equal parts: one was irradiated with 3000 cGy directly after blood donation, and the other served as a control. Cell counts, platelet activation marker CD62 antigen, blood gas values, and supernatant concentrations of K+, Na+, lactate, glucose, interleukin-1 beta (IL-1 beta), IL-8, and tumor necrosis factor-alpha (TNF-alpha) were determined in paired samples on the day of collection (day 0) and after 5 days of storage (day 5).

RESULTS

No significant differences in white cell counts or TNF-alpha concentrations were noted between the irradiated and control platelets on day 0 or day 5, whereas the mean proportion of platelets expressing CD62P (22.65% vs 25%, p = 0.014) and the mean IL-1 beta (45.55 pg/mL vs 52.75 pg/mL, p = 0.004) and IL-8 concentrations (10.68 pg/mL vs 13.07 pg/mL, p = 0.015) were significantly lower in irradiated than control platelets on day 5. The 5-day storage significantly increased the mean proportion of platelets expressing CD62P (25.00% vs 15.02%, p = 0.008), mean PO2 (116.34 mm Hg vs 98.07 mm Hg, p = 0.002), and mean concentrations of K+ (3.30 mmol/L vs 3.06 mmol/L, p < 0.001), lactate (15.12 mmol/L vs 3.23 mmol/L, p < 0.001), IL-1 beta (52.75 pg/mL vs 29.73 pg/mL, p = 0.001), and IL-8 (13.07 pg/mL vs 3.62 pg/mL, p < 0.001). Five-day storage also significantly decreased white cell count (0.18 x 10(8) vs 0.74 x 10(8), p < 0.001), PCO2 (19.38 mm Hg vs 50.51 mm Hg, p < 0.001), and concentrations of HCO3- (10.36 mmol/L vs 21.34 mmol/L, p < 0.001) and glucose (193.37 mg/dL vs 309.18 mg/dL, p < 0.001). Platelet counts and concentrations of IL-1 beta, IL-8, and TNF-alpha on day 0 did not differ significantly between control apheresis platelets collected with the Fenwal CS-3000 Plus and those collected with COBE Spectra. The mean white cell count (1.29 x 10(8) vs 0.19 x 10(8), p = 0.002) and the proportion of platelets expressing CD62P (24.71% vs 7.09%, p < 0.001) on day 0, however, were significantly higher in the platelets collected with the Fenwal CS3000-Plus than in those collected with the COBE Spectra.

CONCLUSIONS

Gamma irradiation of apheresis platelets inhibits the expression of platelet CD62P and the secretion of IL-1 beta and IL-8 after 5 days' storage.

Non-functioning islet cell tumors of the pancreas--a multicentric clinical study in Taiwan

BACKGROUND/AIMS

Islet cell tumors of the pancreas are rare. Functioning tumors are characterized by the symptoms induced by the hormones they secrete. The clinical behaviors of non-functioning tumors are quite different. In this retrospective study, we scrutinized 16 patients with non-functioning islet cell tumor in three tertiary university hospitals in Taiwan during a 20-year period.

METHODOLOGY

There were 12 women and 4 men with a mean age of 47 years. Body-weight loss, abdominal pain and palpable mass were the most frequent symptoms.

RESULTS

The mean size of these tumors was 8.9 cm in diameter. Ten tumors were located at the tail of pancreas, the other 6 located at the head. Except for hyperbilirubinemia in 2 patients, none of the patients with non-functioning islet cell tumor showed abnormalities of laboratory data including serum tumor markers. Preoperative detection of these tumors by imaging modalities was not difficult due to the large size of the tumors. However, differentiation with functioning tumor or ductal cell carcinoma required clinical and imaging correlation. Fourteen tumors were malignant including 8 with regional lymph nodes involvement, 3 with locally microscopic invasion, 2 with hepatic metastasis and 2 with nearby organ invasion.

CONCLUSIONS

Even with its malignant behavior, non-functioning islet cell tumor still possessed a good prognosis after adequate surgical removal in comparison with a higher mortality rate of ductal carcinoma of the pancreas.

Reactive oxidizing species produced near the plasma membrane induce apoptosis in bovine aorta endothelial cells

Many cytotoxic agents initiate apoptosis by generating reactive oxidizing species (ROS). The goal of this study was to determine whether apoptosis could be induced by initial reactions of ROS near the plasma membrane. Bovine aorta endothelial cells (BAEC) were illuminated with evanescent wave visible radiation, which has limited penetration into the basal surface of cells, or by trans-radiation. Imaging of fluorescent dyes localizing in the plasma membrane, mitochondria, or nucleus confirmed that evanescent wave radiation excited only dyes in and near the plasma membrane. Singlet oxygen, an ROS generated by photosensitization, has a very short lifetime, ensuring that it oxidizes molecules residing in or very close to the plasma membrane when evanescent wave radiation is used. Cells with condensed nuclei were considered apoptotic and were quantified after treatment with varying doses of light. Annexin V staining without propidium iodide staining confirmed that these cells were apoptotic. The doses required to induce apoptosis using evanescent wave radiation were 10-fold greater than those needed for trans-irradiation. Quantitative analysis of the evanescent wave penetration into cells supports a mechanism in which the singlet oxygen created near the plasma membrane, rather than at intracellular sites, was responsible for initiation of apoptosis.

Bonded amalgam restorations: using a glass-ionomer as an adhesive liner

Due to the lack of adhesiveness of amalgam to tooth structure, several adhesive cements have been utilized in bonded amalgam restorations. This study evaluated whether Fuji-II glass-ionomer cement is an appropriate adhesive liner in bonded amalgam restorations. Two adhesive composite luting cements (Amalgambond Plus and Panavia-21) and Copalite cavity liner were compared. The study was conducted in two phases. In the first part, we quantitatively assessed the tensile bond strengths as well as the failure modes of amalgam bonded to human dentin, using different adhesive liners. In each group, the flat dentin surface was treated with the assigned adhesive cement with a Teflon mold, followed by condensation of amalgam (Valiant PhD) onto it. Each group's mean tensile bond strengths were recorded and the statistical analysis by one way ANOVA showed no significant differences among groups (p > 0.05). Similar to the fracture patterns of the Amalgambond Plus and Panavia-21 groups, the failure mode of Fuji-II group was predominantly adhesive fracture. In the second part, the fracture strengths of amalgam restored teeth were measured using different adhesive liners. Standard MOD cavities were prepared in each tooth except for the intact tooth group. After treatment with the assigned adhesives or varnish, the cavities were restored with amalgam. Fracture strengths were then measured and the fractured interfaces examined using a scanning electron microscope. The fracture strengths of the intact tooth, Amalgambond Plus, Panavia-21 and Fuji-II groups were significantly higher than those of the Copalite and prepared cavity without restoration groups (p < 0.01). Accordingly, Fuji-II glass-ionomer cement, when used as an adhesive liner of amalgam restoration, may effectively reinforce the remaining tooth structure and, therefore, enhance the fracture resistance of the amalgam-restored teeth.

A comparison of the morphological changes after Nd-YAG and CO2 laser irradiation of dentin surfaces

The purpose of this study was to compare the morphological changes after Nd-YAG and CO2 laser irradiation on dentin surfaces with or without the smear layer. Eighty-one 3-mm-thick dentin specimens collected from the middle third of molar crowns were used. The dentin surfaces were ground to #320, #400, and #600 grit in series to create a smear layer. Half of the specimens were treated with 14% EDTA for 2 min to remove the smear layers. The lasers were applied on each specimen perpendicularly with 1-mm focus distance to the dentin surface for 4 s. The parameters for the Nd-YAG laser were 50 mJ, 100 mJ, and 150 mJ at 10 pps, 20 pps, and 30 pps, and for the CO2 laser were 2 W, 3 W, and 4 W at 5 ms x 20 pps, 10 ms x 10 pps, 20 ms x 20 pps, 50 ms x 2 pps, 100 ms x 2 pps, and 200 ms x 2 pps. The results showed that the Nd-YAG laser caused crater and melting of the dentin surface, especially in dentin specimens with smear layers. The CO2 laser produced extensive cracking lines on dentin surfaces with a smear layer, whereas surface erosion and crater formation were found on specimens without a smear layer. In conclusion, both the laser types and smear layer have a significant influence on the morphological changes of dentin surfaces irradiated by lasers.

Selective delivery of laser energy to biological tissue based on refractive-index differences

We report a novel method for selective laser energy delivery into biological tissues based on refractive-index differences. As a specific example, Ho:YAG laser energy is delivered into fat preferentially over other soft tissue, despite the fact that water has a higher absorption coefficient at this wavelength than fat.

Vaccination against gonadotropin-releasing hormone (GnRH) using toxin receptor-binding domain-conjugated GnRH repeats

A method for the preparation of an immunogen containing multiple copies of a self-peptide in linear alignment was designed in order to overcome the difficulty of inducing an immune response to poorly immunogenic peptide antigens. DNA fragments encoding multiple repeats of the self-peptide were generated by a new technique, termed template-repeated polymerase chain reaction (TR-PCR), which could be subcloned into an expression vector for production of peptide repeats as an immunogen. This approach was tested by constructing fusion proteins containing the receptor-binding domain of Pseudomonas exotoxin A and multiple copies of the 10-residue sequence of the peptide hormone gonadotropin-releasing hormone (GnRH). Immunization of female rabbits with the immunogen that contained the exotoxin receptor-binding domain and 12 copies of GnRH (PEIa-GnRH12) resulted in the generation of high-titer antibodies specific for GnRH. Although at equal molar basis of the GnRH moiety, the immunogen that contained single copy of GnRH (PEIa-GnRH1) induced low-titer anti-GnRH antibodies. These observations suggest that the presence of multiple peptide repeats is a key factor in eliciting an immune response. In addition, anti-GnRH antibodies effectively neutralized GnRH activity in vivo, as demonstrated by the degeneration of the ovaries in the injected rabbits. Because anti-GnRH antibody could be functionally analogous to GnRH antagonist, which has been used to treat patients with ovarian cancer, vaccination of PEIa-GnRH12 presents a potential therapeutic application for the treatment of GnRH-sensitive ovarian cancer.

Fiber-coupled multiplexed confocal microscope

We describe a new parallel scanning mechanism for confocal microscopy that is inherently fiber-optic compatible and that retains the simplicity of the line scanning confocal microscope. The method works by employing an incoherent fiber-optic bundle that maps a line illumination pattern back on itself on double passing, while separating the fibers that carry photons from out-of-focus sample planes. The transformation permits efficient rejection of out-of-focus photons by a slit aperture.

Successful treatment of all-trans retinoic acid resistant and chemotherapy naïve acute promyelocytic patients with arsenic trioxide--two case reports

Arsenic trioxide(As2O3) has proved highly effective in treating both refractory or primary cases of acute promyelocytic leukemia (APL). The role of arsenic trioxide in APL treatment has been confirmed by study groups in China and in the USA. However, what is the role of As2O3 in treating APL? Should it be used as first line therapy, or should it be used as a second line drug. This still remains to be defined. Here, we report two cases of APL, who were treated successfully with As2O3 when they relapsed. Initially, both received all-trans retinoic acid (ATRA) for primary remission induction therapy, and obtained a complete remission. For ethical or personal reasons, they did not receive chemotherapy as consolidation therapy and when they relapsed at 23 months and 12 months later respectively, they both received As2O3 therapy after being resistant to ATRA treatment. Two courses of As2O3 were given and both reached complete remission. There were very few adverse reactions to the drug, only mild abdominal cramps, mild fluid retention, and transient elevation of transaminases. They both had rather good quality of life throughout the treatment and both remain in remission for 32 months and 10 months since therapy, respectively.

Reversible axial myopia following infectious scleral ulceration--a case report

Adult-onset axial myopia is uncommon in comparison with the lenticular myopia. When we dealt with a case of the infectious scleral ulceration, the progressive myopic shift was not only due to the dense nuclear sclerosis but also due to the longer axial length. The elongating axis became shortened after 3-months follow up. Then the patient underwent uneventful cataract surgery. However, the reversal process persisted even after the operation. Although the pathogenesis is not well known, we concluded that the cataract surgery in dealt with the complicated cataract should be delayed in the cases with any inflammation or the axial changes.

Treatment of tooth fracture by medium energy CO2 laser and DP-bioactive glass paste: thermal behavior and phase transformation of human tooth enamel and dentin after irradiation by CO2 laser

Acute trauma or trauma associated with occlusal disharmony can produce tooth crack or fracture. Although several methods are proposed to treat the defect, however, the prognosis is generally poor. If the fusion of a tooth fracture by laser is possible it will offer an alternative to extraction or at least serve as an adjunctive treatment in the reconstruction. The responses of soft tissues to lasers of different wavelengths are fairly well known, but the reactions of hard tissues are still to be understood. The purpose of this research was to study the feasibility of using a medium energy continuous-wave CO(2) laser and a low melting-point bioactive glass to fuse or bridge tooth fractures. The present report is focused on the first part of the research, the analysis of changes in laser-irradiated human tooth enamel/dentin by means of X-ray diffractometer (XRD), Fourier-transforming infrared spectroscopy (FTIR), differential thermal analysis/thermogravimetric analysis (DTA/TGA), and scanning electron microscopy (SEM). After CO(2) laser irradiation, there were no marked changes in the X-ray diffraction pattern of the enamel when compared to that before laser treatment. However, a small peak belonging to alpha-TCP appeared at the position of 2theta=30.78 degrees C. After being treated with CO(2) laser, the dentin showed much sharper peaks on the diffraction patterns because of grain growth and better crystallinity. alpha-TCP and beta-TCP were identified after laser treatment. In the FTIR analysis, an HPO(4)(-2) absorption band was noted before laser treatment disappeared after the irradiation. No significant change in the absorption band of HPO(4)(-2) was found on the FTIR curves of enamel after laser treatment. The results of DTA/TGA indicated that loss of water and organic materials occurred in both enamel and dentin after laser treatment. Under SEM, melting and resolidification occurred in both enamel and dentin by medium energy of CO(2) laser. This implies that using a continuous-wave CO(2) laser of medium energy density to fuse a low melting-point bioactive glass to the enamel/dentin is possible. We believe these phase changes and thermal data can make a useful guide for future studies on the thermal interaction and bridging mechanism between the bioactive glass and enamel/dentin under CO(2) laser irradiation.

Gastrointestinal metastasis in hepatocellular carcinoma: radiological and endoscopic studies of 11 cases

BACKGROUND

From October 1990 to January 1999, 11 of 2237 hepatoma patients at our hospital had gastrointestinal tract metastasis. We describe the radiological and endoscopic features, clinical course and prognoses of those patients.

METHODS

All patients were male. Six patients were hepatitis B carriers, and cirrhosis was noted in eight patients on admission. We reviewed all available radiological, endoscopic and pathological features.

RESULTS

The commonest clinical presentation was frank gastrointestinal bleeding. Histological proof of gastrointestinal involvement was seen in six patients. Endoscopic features included ulcerative tumours mimicking advanced gastric carcinoma (43%) and submucosal tumours (29%). The sites of organ involvement were stomach (five), duodenum (two), colon (three) and duodenum and colon (one). Direct invasion by a contiguous neoplasm was the major route of gastrointestinal tract metastasis. Portal vein thrombosis may be the key point of haematogenous spread to other sites.

CONCLUSIONS

The prognosis in these patients was extremely poor. Almost all patients died within 5 months if no further aggressive management was performed. Surgical intervention may be the optimal choice for palliative treatment of HCC with gastrointestinal tract involvement.

Recurrent gastrointestinal bleeding and high output cardiac failure caused by hereditary hemorrhagic telangiectasia

Hereditary hemorrhagic telangiectasia, commonly known as Osler-Weber-Rendu disease, is a systemic autosomal dominant inherited disorder, that occurs in Caucasian populations. We report the case of a 56-year-old housewife who was admitted to the gastrointestinal and cardiovascular ward because she had suffered from recurrent gastrointestinal bleeding and heart failure from 1994 to 1997. Panendoscopy showed vascular ectasia scattered over the tongue, larynx, esophagus, and posterior wall of the gastric body. Colonoscopy showed clusters of telangiectasia over the cecum and ascending colon. Arteriovenous malformations (AVMs) were found in the liver and lungs on computerized tomography. Recurrent gastrointestinal bleeding was controlled by estrogen treatment during the follow-up period. In July 1997, the patient was readmitted to our cardiovascular section due to aggravated dyspnea, orthopnea and bilateral lower leg edema. Cardiac catheterization showed a large fistula from the left pulmonary artery to the left atrium and left ventricle, pulmonary arterial pressure of 37/13 mmHg and cardiac output of 9.61/minute. Other studies excluded the possibility of sepsis, and high-output cardiac failure was suspected. The patient was discharged in a stable condition and scheduled for AVM embolization management. Unfortunately, she died of a suspected heart attack at home two weeks following discharge.

Effect of fortified antibiotic solutions on corneal epithelial wound healing

PURPOSE

To evaluate the influence of fortified antibiotic eyedrops on corneal epithelial wound healing.

METHODS

We developed an in vitro epithelial wound-healing model to evaluate the toxicity of antibiotics. An excimer laser was used to create an epithelial defect 1.5 mm in diameter, 70 microm in depth on the central area of porcine cornea. The intact animal globes were maintained in the incubator by a perfusion system. Fortified antibiotics: 10% piperacillin, 5% cefazolin, 0.5% chloramphenicol, 5% vancomycin, 1% amikacin, 2% gentamicin, and 0.1% amphotericin B were applied to the wound in three applications. The wounds were evaluated 24 h after setup with fluorescein stain and a scoring system.

RESULTS

The 0.1% amphotericin B and 2% gentamicin disturbed the corneal epithelial healing rate significantly. The remaining antibiotics did not interfere with the epithelial healing rate in our study design.

CONCLUSION

Fortified antibiotic eyedrops demonstrated varied degrees of influence on corneal epithelial wound healing. When antibiotic eyedrops are used, both the efficacy and toxicity of the antibiotics should be the major concern. If efficacy is equivalent, less-toxic agents should be given preference.

Combined use of an amniotic membrane and tissue adhesive in treating corneal perforation: a case report

We report a new method combining the use of an amniotic membrane and cyanocrylate tissue adhesive to seal a corneal perforation. A 47-year-old male suffered from an alkali injury complicated with corneal melting and perforation in the left eye. We placed an amniotic membrane of optimal size in the anterior chamber directly under the corneal perforation lesion. The cyanocrylate tissue adhesive was then applied over the perforation site and sealed successfully. Three weeks later, the tissue adhesive had dislodged. The amniotic membrane had sealed the perforated lesion and was well adhered to the surrounding corneal tissue with complete epithelial covering. Vision was 20/25 six months after the operation. The combined use of an amniotic membrane and tissue adhesive is a promising method in the treatment of corneal perforation.

Treatment of tooth fracture by medium energy CO2 laser and DP-bioactive glass paste: compositional, structural, and phase changes of DP-bioglass paste after irradiation by CO2 laser

Nowadays, fractured teeth are difficult to treat effectively. Currently, root fractures are usually treated by root amputation, hemisection or tooth extraction. If the fusion of tooth fracture by laser were possible, it would offer a different therapy to repair fracture teeth. We tried to use a developed DP-bioactive glass paste to fuse or bridge the tooth crack line by a medium energy continuous-wave CO2 laser. The study is divided into three parts: (1) The compositional and structure changes in tooth enamel and dentin after laser treatment; (2) The phase transformation and recrystallization of DP-bioactive paste during exposure to the CO2 laser; (3) The thermal interactions and bridge mechanism between DP-bioactive glass paste and enamel/dentin when they are subjected to CO2 laser. The present report will focus on the second part that will examine the changes of laser-exposed DP-bioactive glass paste by means of X-ray diffractometer (XRD), Fourier transforming infrared spectroscopy (FTIR), differential thermal analysis/thermogravimetric analysis (DTA/TGA), and scanning electron microscopy (SEM). From the study, we could find that the temperature increase due to laser irradiation is greater than 900 degrees C and that the DP-bioactive glass paste could be melted in a short period of time after irradiation. In the study, we successfully developed a DP-bioactive glass paste which could form a melting glass within seconds after exposure to a medium energy density continuous-wave CO2 laser. The paste will be used in the near future to bridge the enamel or dentin surface crack by the continuous-wave CO2 laser.

Corneal subepithelial opacities associated with inappropriate contact lens care

PURPOSE

To report two cases of corneal subepithelial opacities, which may be related to improper lens care by the patients.

METHODS

Slit-lamp examination and monitoring of contact lens care procedures.

RESULTS

Two female patients experienced similar symptoms of soreness, blurring, and red eyes after wearing soft contact lenses. Slit-lamp examinations demonstrated numerous subepithelial opacities in the central cornea. Both patients used the same kind of cleaner (MiraFlow) inappropriately, which resulted in the possibility of residual cleaner remaining in the lenses. The symptoms and signs gradually subsided after discontinued use of soft contact lens and application of topical steroid.

CONCLUSIONS

Residual MiraFlow in soft contact lenses may result in corneal subepithelial opacities.

Recombinant protein composed of Pseudomonas exotoxin A, outer membrane proteins I and F as vaccine against P. aeruginosa infection

We have constructed a chimeric protein composed of the receptor binding and membrane translocation domains of Pseudomonas exotoxin A (PE) with the outer membrane proteins I and F, together designated as PEIF. The potential of PEIF as a vaccine against Pseudomonas infection was evaluated in BALB/c mice and New Zealand white rabbits. We examined titers of anti-PE and anti-OprF antibodies, and the ability both to neutralize PE cytotoxicity and to increase opsonophagocytic uptake of Pseudomonas aeruginosa strain PAO1, serogroups 2 and 6. The results showed that PEIF can induce antibodies not only to neutralize the PE cytotoxicity but also to promote the uptake of various strains of P. aeruginosa by murine peritoneal macrophages. In a burned mouse model, PEIF afforded significant protection against infection by the homologous P. aeruginosa strain PAO1, heterologous serogroup 2, and the PE hyperproducing strain PA103. These observations thus indicate that PEIF may be used as a novel vaccine against P. aeruginosa infection.

Root deformation during root-end preparation

Ultrasonic root-end preparation techniques have recently been introduced and revolutionized the field of endodontic surgery. However, several reports claimed that there was an increasing incidence of crack formation after ultrasonic root-end preparation. As yet, little work has focused on the root deformation during root-end preparation. Thus, the purpose of this investigation was to measure the amount of root deformation during root-end preparation with the use of microhandpiece and ultrasonic systems by using strain gauge methods, and simultaneously to detect any cracks with the aid of the stereomicroscope, stain, and an image processing system. The results demonstrated the ultrasonic instrumentation produced significantly greater strain on average than that generated with the microhandpiece system. From the viewpoint of fracture, any technique that could diminish the strain on the root would decrease the likelihood of fracture; however, no crack was observed on any resected surface of roots in this study.

Toxic effects of mitomycin-C on cultured corneal keratocytes and endothelial cells

Improper use of mitomycin-C in ocular medication may result in damage to corneal cells. In this study, the toxic effects of mitomycin-C on cultured porcine keratocytes and endothelial cells were estimated by MTT, 3H-thymidine uptake and cellular counting assay methods. It was found that mitomycin-C caused a dose-dependent toxic effect to keratocytes and endothelial cells. Both cells were treated with mitomycin-C at the concentration ranging from 100, 10, 1, 0.1 to 0.01 microg/ml for 3 min, 5 min or 100 min. The 50% inhibitory dose (ID50) of mitomycin-C to keratocytes and endothelial cells as measured by MTT assay was 0.40, 0.18, 0.16 mg/ml and 0.27, 0.15, 0.14 mg/ml, respectively, after 3, 5 and 100 minutes drug treatment. The ID50 for keratocytes and endothelial cells as measured by 3H-thymidine uptake immediately, 1 day and 7 days after 100 minutes mitomycin-C treatment was 0.3, 0.0002, 143.2 microg/ml and 45.1, 101.1, 450.2 microg/ml, respectively. The ID50 for keratocytes and endothelial cells as measured by cellular counting 1 day and 7 days after mitomycin-C treatment was 232.5, 109.7 microg/ml and 239.9, 367.5 microg/ml, respectively. It is concluded that mitomycin-C is more toxic to cellular proliferation in cultured corneal keratocytes than in endothelial cells.

Precise, controlled laser delivery with evanescent optical waves

Precise laser surgery is possible with laser pulses at wavelengths that are strongly absorbed at the surface of tissue. However, pulses at these wavelengths (far UV, far infrared) are not compatible with fiber-optic transmission, making endoscopic surgical procedures inside the body difficult. We use evanescent optical waves to demonstrate an alternative for confining energy near the tissue surface. Precise, superficial tissue ablation is achieved with evanescent waves generated at a sapphire-tissue interface by a free-electron laser, where the ablation depth may be varied. A new class of precise, controlled laser surgical tools may be achieved in this novel approach for use in endoscopic procedures. Electromagnetic theory governing evanescent-wave tissue ablation is presented.

A nontoxic Pseudomonas exotoxin A induces active immunity and passive protective antibody against Pseudomonas exotoxin A intoxication

Pseudomonas exotoxin A (PE) is one of the most potent cytotoxic agents produced by Pseudomonas aeruginosa. In this study, we examined the possibility of using PE with a deletion of 38 carboxyl-terminal amino acid residues, designated PE(Delta576-613), for active immunization against PE-mediated disease. We first examined the toxic effects of PE and PE(Delta576-613) on 5- and 9-week-old ICR mice. The results show that the subcutaneous administration of PE(Delta576-613) at a dose of 250 microg was still nontoxic to 5- and 9-week-old ICR mice, while native PE was lethal at a dose of 0.5 and 1 microg, respectively. PE(Delta576-613) was then used to immunize ICR mice. The minimum dose of PE(Delta576-613) that could effectively induce anti-PE antibodies in 5- and 9-week-old ICR mice was found to be 250 ng. However, immunization with 250 ng PE(Delta576-613) failed to protect the immunized mice from a lethal dose of PE. The effective immunization dose of PE(Delta576-613) that could protect mice against a 2 microg PE challenge was found to be 15 microg. In addition, sera obtained from PE(Delta576-613)-immunized ICR mice were able to neutralize PE intoxication and effectively protect mice from PE. Thus, PE(Delta576-613) may be used as an alternative route to new PE vaccine development.

The combined occluding effect of sodium fluoride varnish and Nd:YAG laser irradiation on human dentinal tubules

Various methods and materials used in the treatment of dentin hypersensitivity are thought to achieve a therapeutic benefit by tubule occlusion. The aim of the present study was to evaluate the combined occluding effect of sodium fluoride varnish and Nd:YAG laser irradiation on human dentinal tubules. Thirty-six dentin specimens with exposed dentinal tubule orifices were used in this study. The samples were randomly divided into four groups. Groups A, B, and C were varnished by sodium fluoride, whereas group D served as a control. Then, group C was lased by 30 mJ of Nd:YAG laser, 10 pulses/s for 2 min by light painting. Three hours later, groups B and C were brushed by an electrical toothbrush for 30 min. Under SEM observation, the control group showed numerous exposed dentinal tubule orifices, and the sodium fluoride varnished specimens showed closure of exposed dentinal tubule orifices. After electrical toothbrushing, most of the sodium fluoride varnish was brushed away, except in the specimens that were irradiated by Nd:YAG laser. Over 90% of the dentinal tubule orifices were occluded by sodium fluoride varnish combined with Nd:YAG laser irradiation.

Fungal corneal ulcers of onion harvesters in southern Taiwan

Fungal corneal ulcers related to agriculture has been reported throughout the world, especially in tropical areas. Most of them were sporadic and had histories of ocular trauma or use of topical corticosteroids and topical antibiotics. Five onion harvesters had fungal corneal ulcers during the same harvest period in Southern Taiwan. The authors think that this is the first report of a group occurrence relating to agricultural workers. Although all of the patients improved after medical and surgical management, their vision was greatly decreased. It is suggested that the tropical climate, the harvest procedure, the characteristic monsoon, and lack of eye protection were involved. Therefore, the importance of the eye protection, hygiene education, and improving medical care to reduce the occurrence of fungal corneal ulcer in agriculture workers must be emphasised.

Effect of reaction conditions on preparations of rhenium-188 hydroxyethylidene diphosphonate complexes

Rhenium-186 (Re-186) hydroxyethylidene diphosphonate (HEDP) has been shown to localize in metastatic foci within bone in a manner similar to Tc-99m bone-seeking agents. Usually, in the preparation of diagnostic Tc-99m radiopharmaceuticals, the concentration of Tc is at trace level (10(-8) M). However, large amounts of carrier are included in the preparation of Re-186 radiopharmaceuticals (10(-4) M), which may significantly affect the preparation of Re-HEDP. In this study, Re-188 was used as an Re tracer. The effects of pH and concentrations of Re carrier on the preparation of Re-HEDP were investigated. Re-188-Sn-HEDP was prepared by reconstitution of a kit of lyophilized HEDP mixture, and tin chloride with a radioactive solution of perrhenate in saline. The total concentration of Re present in this work ranged from 10(-8) to 10(-3) M. The results showed that high labeling efficiency was obtained for each preparation. Although the chemical behaviors of the Re-188 HEDP complexes, with and without carrier, were similar, the biodistribution patterns of carrier free Re-188 HEDP in rats were found to differ from the biodistribution patterns of carrier-added Re-188 HEDP.

Vertical root fracture in endodontically versus nonendodontically treated teeth: a survey of 315 cases in Chinese patients

OBJECTIVE

The purpose of this study was to compare endodontically versus nonendodontically treated teeth with respect to clinical features, including patient age and gender and tooth types of vertical root fractures.

STUDY DESIGN

A total of 315 consecutive cases of vertical root fracture occurring in 274 Chinese patients during a 1 3-year period were reviewed. Age and gender, as well as tooth type and root distribution of vertical root fractures, were presented and compared in endodontically versus nonendodontically treated teeth.

RESULTS

Most patients (87%) had 1 fractured tooth; the others had 2 or 3 fractured teeth. Of all vertical root fractures, 40% occurred in nonendodontically treated teeth. In comparison with those in endodontically treated teeth, vertical root fractures in nonendodontically treated teeth tended to occur in patients with a higher mean age (55 years vs. 51 years) and were more frequent in male patients (78% vs. 58%). Vertical root fractures occurred in nonendodontically treated teeth more often in molars (84% vs. 53%), less often in premolars (16% vs. 33%), and seldom in anteriors (1 tooth vs. 27 teeth).

CONCLUSIONS

Vertical root fractures in nonendodontically treated teeth are not uncommon and comprise a large proportion of such fractures in Chinese patients. Differences between endodontically and nonendodontically treated teeth in patient age and gender, as well as in tooth types of vertical root fractures, were demonstrated.

Ultrastructural changes of the tooth root surface by Nd:YAG laser irradiation followed by citric acid and tetracycline

The neodymium:yttrium-aluminum-garnet (Nd:YAG) laser has been used for treatment of dentinal hypersensitivity, eradicating periodontal pathogens, and facilitating calculus removal. However, Nd:YAG laser irradiation exerts potentially harmful effects on the tooth root surface. The purpose of this study was to examine the ultrastructural changes of the tooth root surface caused by Nd:YAG laser irradiation, and to determine whether chemical and mechanical preparations can correct these ultrastructural changes. Eighteen tooth specimens (3 x 3 x 0.5 mm) with healthy root surfaces were prepared and irradiated with an Nd:YAG laser at various power densities. Root surfaces were irradiated at 100 mJ at 20 pulses per second (pps) for 2 seconds followed by the application of citric acid (pH 1.2) or tetracycline solution (100 mg/mL) for 3 and 5 minutes, respectively, or ultrasonic scaling for 5 strokes of 3 seconds per stroke. As observed with low-vacuum scanning electron microscopy, (Wet-SEM), Nd:YAG laser irradiation at 70 to 100 mJ, 20 pps for 2 seconds caused surface cratering, areas of porosity, pitting, fissures, and lava-like structures in an area 140 to 280 microns in diameter. Irradiation of 50 mJ, 20 pps for 2 seconds, led to only mild surface charring. No evidence of morphologic changes was found when root surfaces were irradiated with the Nd:YAG laser at 20 mJ, 20 pps for 2 seconds or at 50 mJ, 10 pps for 8 seconds. The laser-induced lava-like structures were partially detached by citric acid (pH 1.2) etching and ultrasonic scaling, but not by tetracycline (100 mg/mL). These results indicate that chemical and mechanical preparations can be used effectively in conjunction with Nd:YAG laser irradiation for root surface preparation during both nonsurgical and surgical periodontal treatments.

Intraocular use of fluconazole in the management of ocular fungal infection

In this study, we investigate the efficacy and safety of intraocular use of fluconazole in the treatment of ocular fungal infection. Ten patients with intraocular fungal infections were examined. Among these patients, eight were infected with keratomycosis with intraocular spreading, one had postoperative fungal endophthalmitis after cataract operation with an intraocular lens implant, and another suffered from endogenous fungal endophthalmitis. In addition to the conventional local application with or without systemic administration of antifungal drugs, all ten patients were treated with intraocular administration of 5-10 micrograms/ml of fluconazole. The ocular fungal infections resolved in nine patients without obvious side effect. One failed in the antifungal treatment with loss of vision. In our experience, the results revealed that fluconazole is a safe and effective antifungal agent that can be administered intraocularly. We suggest that intraocular administration of this drug could be considered as an alternative or additional choice for the treatment of severe ocular fungal infections.

Thrombin activates the growth, cell-cycle kinetics, and clustering of human dental pulp cells

Thrombin is activated during vascular injury and inflammation of the dental pulp. In the present study, we found that thrombin can stimulate the proliferation of pulp cells in a dose-dependent manner as analyzed by modified MTT assay. The cell number increased by 1.6, 1.77, and 2.14-fold over that of control after exposure to 5, 10, and 20 units/ml of thrombin for 5 days. Flow cytometry studies also found that thrombin (10 units/ml) can induce the cell cycle progression of pulp cells after 24 h of incubation, as revealed by increasing the proportion of cells in the S phase and the G2/M phase from 29 to 72%. Moreover, exposure to thrombin (> 5 units/ml) for 3 days led to marked clustering of pulp cells. We concluded that thrombin can regulate the growth, cell cycle progression, and functional reorganization of the pulp tissue during pulp healing and inflammatory processes.

Progressive outer retinal necrosis syndrome as an early manifestation of human immunodeficiency virus infection

Progressive outer retinal necrosis syndrome is a recently recognized variant of necrotizing herpetic retinopathy, developing in patients with acquired immune deficiency syndrome (AIDS) or other conditions causing immune compromise. We report a case in which the diagnosis of retinal necrosis syndrome was made before the diagnosis of AIDS was confirmed. A 41-year-old man presented with a 1-month history of blurred vision in his left eye. Ophthalmologic examination revealed extensive retinal necrosis with total retinal detachment in his left eye and multifocal deep retinal lesions scattered in the posterior fundus as well as in the peripheral retina in his right eye. The serologic test for human immunodeficiency virus (HIV) was positive. Despite intravenous acyclovir treatment for 1 week, the lesions in the right eye showed rapid progression. High doses of intravitreal ganciclovir were then given in addition to intravenous acyclovir. After combined treatment for 1 month, the lesions became quiescent and the visual acuity improved to 20/30. Although the patient soon developed full-blown AIDS, the vision in his right eye remained undisturbed. Physicians should suspect progressive outer retinal necrosis syndrome in any patient with rapidly progressive necrotizing retinopathy and test the patient for HIV infection. Aggressive combined antiviral agent therapy should be considered to save vision.

Stability of self-prepared fortified antibiotic eyedrops

Self-prepared fortified antibiotic eye drops are essential for the severe ocular infection. The relation of potency decay and storage conditions including temperature, concentration and duration were studied by the changes of MIC. 1% and 10% amikin, 10% and 50% pipril, and 5% and 25% vancomycin were diluted from the prarenteral antibiotics with the 5% glucose and storage at 4, -18 and -80 degrees C for 3, 7, 14 and 28 days. MICs of amikin against Pseudomonas aeruginosa, pipril and vancomycin against Staphylococcus aureus were determined by the agar diffusion method. Fluctuations of the MIC were noted during the observation period. Most of the significant changes of MIC were found during the first 7 days. When the potencies between time of zero and 28 days are compared, only 10% pipril and 25% vancomycin stored at -80 degrees C had significant change. Our conclusion is that all of the fortified antibiotic eye drops in this study can be stored in the house refrigerator or freezer for up to 28 days. High concentration may show a negative result of the preservation. Temperature does not influence the preservative effect within four weeks' observation.

Influences of methylcellulose on corneal epithelial wound healing

We performed a study to evaluate the influence of methylcellulose (MC) on the corneal epithelial wound healing. A precise epithelial wound 2.0 mm in diameter and 70 microm in depth was created by an excimer laser on the cornea of a pig's eyeball. After treatment, the eyeballs were cultured in the incubator and perfused with TC-199 medium into the vitreous cavity. Topical MC with eight different combinations of concentrations and viscosities for experimental groups and BSS for the control group were applied on the epithelial defects three times. Wounds were evaluated 24 hours later with fluorescein stain and recorded with a scoring system. All of the experimental groups except one showed a more statistically significant superior wound-healing rate than the control group. MC possesses the effect to accelerate corneal epithelial wound healing.