Quantification of bone marrow interstitial pH and calcium concentration by intravital ratiometric imaging

The fate of hematopoietic stem cells (HSCs) can be directed by microenvironmental factors including extracellular calcium ion concentration ([Ca2+]e), but the local [Ca2+]e around individual HSCs in vivo remains unknown. Here we develop intravital ratiometric analyses to quantify the absolute pH and [Ca2+]e in the mouse calvarial bone marrow, taking into account the pH sensitivity of the calcium probe and the wavelength-dependent optical loss through bone. Unexpectedly, the mean [Ca2+]e in the bone marrow (1.0 ± 0.54 mM) is not significantly different from the blood serum, but the HSCs are found in locations with elevated local [Ca2+]e (1.5 ± 0.57 mM). With aging, a significant increase in [Ca2+]e is found in M-type cavities that exclusively support clonal expansion of activated HSCs. This work thus establishes a tool to investigate [Ca2+]e and pH in the HSC niche with high spatial resolution and can be broadly applied to other tissue types.

[Debulking strategy of endovascular treatment for lower extremity artery lesions]

Objective: To explore the debulking strategy of lower extremity artery lesions. Methods: Retrospectively analyzed the clinical data of 101 patients underwent debulking therapy at Department of Vascular Surgery,Zhongshan Hospital,Fudan University from June 2019 to June 2020.There were 74 males and 27 females,aged (73.2±11.7)years (range:35 to 93 years).There were 31 cases in Rutherford class 3,39 cases in class 4 and 31 cases in class 5. Hypertension occurred in 72 patients. One hundred and forty lesions were treated in 101 patients. Among them, there were 13 lesions(9.3%) in iliac artery,72 lesions(51.4%) in superficial femoral artery,41 (29.3%) lesions in popliteal artery,10 lesions(7.1%) in tibiofibular trunk,and 4 lesions(2.9%) in below the knee artery.Percutaneous mechanical thrombectomy (PMT) was mainly used in acute thrombosis,excimer laser ablation (ELA) was mainly used for chronic in-stent restenosis and chronic stenosis or totally occlusive lesions,while directional atherectomy (DA) was mainly used for short calcified lesions. Results: All of the patients underwent debulking therapy. Eighty-two lesions(58.6%,82/140) were treated by PMT, 56 (40.0%,56/140) were treated by ELA,and 2 (1.4%,2/140) were treated by DA.The ankle-brachial index of the patient was 0.44±0.19 before surgery, 0.87±0.17 immediately after surgery (t=-16.26, P<0.01), and 0.81±0.20 at 6 months after surgery(t=-14.67,P<0.01),and 0.79±0.15 (t=-14.12,P<0.01) at 12 months after surgery. At 12 months,the primary patency was 86.1% (87/101),mortality was 5.0% (5/101), freedom from major-amputation survival rate was 93.1% (94/101),and target lesion reintervention rate was 9.9% (10/101). Conclusions: Debulking is feasible and effective to eliminate the arterial contents and maximize the acquisition of lumen.Selection of suitable debulking methods for different segments and lesions would be helpful to improve the technical success and obtain satisfactory results.

[Application and value of excimer laser ablation in the treatment of lower limb atherosclerotic obliterans]

Objective: To evaluate the results of excimer laser ablation (ELA) in the treatment of lower limb atherosclerotic obliterans (ASO). Methods: From June 2019 to March 2020, patients who underwent ELA combined with drug-coated balloon (DCB) for lower limb atherosclerotic obliterans (ASO) were enrolled. Demographics, lesion characteristics, procedure-related outcomes and complications were collected and analyzed. Results: Thirty patients were enrolled, including 21 males and 9 females. The mean age was (76.5±10.5) years. The mean lesion length was (11.7±6.4) cm. A total of 41 lesions, including in-stent restenosis (ISR) in 12 (29.3%), chronic totally occlusion (CTO) at initial treatment in 24 (58.5%), and severe stenosis in 5 (12.2%) patients. Sixteen (51.6%) patients were classified as Peripheral Arterial Calcium Scoring System (PACSS) category 4. The technical success rate was 93.5%. Incidence of distal embolization and bailout stenting was 12.9% and 6.5%, respectively. The mean follow-up time was (6.6±3.0) months. Ankle-brachial index (ABI) was significantly increased from 0.43(0.32,0.55) preoperatively to 0.91(0.87,1.01) postoperatively (Z=-5.43, P<0.01) and 0.82(0.73,1.02) (Z=-3.99, P<0.01) three months after surgery. The 3-month major-amputation free survival rate was 96.7%, primary patency rate was 100%, the target lesion reintervention (TLR) rate was 0 and ulcer healing rate was 76.9%. Conclusion: Debulking of ELA is feasible and effective for both ISR and CTO at initial treatment, providing a new option for DCB preparation and reducing stent implantation.

Characteristics of sepsis-induced cardiac dysfunction using speckle-tracking echocardiography: a feasibility study

Septic cardiomyopathy is commonly encountered in patients with severe sepsis and septic shock. This study explores whether novel global and segmental echocardiographic markers of myocardial deformation, using two-dimensional speckle tracking, are associated with adverse sepsis outcomes. We conducted a retrospective observational feasibility study, at a tertiary care centre, of patients admitted to the ICU with a diagnosis of sepsis who underwent an echocardiogram within the first week of sepsis diagnosis. Data were collected on chamber dimensions, systolic and diastolic function, demographics, haemodynamics, and laboratory parameters. Global and segmental left ventricular longitudinal strain (LVLS) and tissue mitral annular displacement (TMAD) were assessed on 12 left ventricular segments and six mitral annulus segments in apical views, respectively. We explored associations of abnormal LVLS and TMAD with duration of mechanical ventilation, hospital length of stay, and mortality. Fifty-four patients were included. Global LVLS was not associated with any of the primary study endpoints. However, reduced systolic LVLS of the basal anterior segment was associated with in-hospital mortality. There was a suggestion that patients with a reduced global TMAD were associated with an increased risk of mortality and a short length of hospital stay but these associations were not statistically significant. Reduced global LVLS was associated with lower ejection fraction. Reduced global TMAD was associated with reduced global and segmental LVLS, reduced left ventricular ejection fraction, and increased left ventricular end-systolic and end-diastolic volumes. Speckle-tracking echocardiography can be performed feasibly in patients in sepsis. Global and segmental left ventricular deformation indices are associated with ejection fraction. Further studies need to evaluate the ability of these new indices to predict sepsis outcomes.

Fatigue life enhancement of NiTi rotary endodontic instruments by progressive reciprocating operation

AIM

To evaluate the effect of reciprocating amplitude and progressive angular increment on fatigue life enhancement of NiTi rotary endodontic instruments.

METHODOLOGY

ProTaper F2 instruments were operated in steel artificial canals with both stationary reciprocating (SR) and progressive reciprocating (PR) motions. The SR motions involved symmetric to and fro reciprocation of ± 180(o) , ± 135(o) , ± 90(o) , ± 60(o) and ± 45(o) . The PR motions were ± 45(o) stationary motion superimposed with angular increments of 7(o) , 11(o) , 22.5(o) or 31(o) whenever an instrument completed 1, 10 or 30 reciprocating cycles (rc). The fatigue lives were compared with those under continuous rotation (CR) and a reciprocating operation with a forward 144(o) and backward 72(o) motion proposed by Yared (2008). The statistical significance of these operating modes on fatigue life was examined using one way anova and post hoc Tukey's tests at P = 0.05. Fractographic analysis was also applied to probe the fracture mechanisms of different rotation motions.

RESULTS

Fatigue life increased with decreasing reciprocating amplitude. Operating in the SR increased fatigue life by 355% over that in the CR. Except for the 22.5(o) increment, all PR motions yielded longer fatigue lives than the SR motion. A progressive reciprocating operation with a ± 45(o) reciprocating amplitude and a + 7(o) progressive angular increment every 10 reciprocating cycles (± 45(o) /10rc/+7(o) ) increased fatigue life by 990% over that in the CR motion. In terms of life enhancement over the CR motion, the larger the curvature the less are the differences between different movements. Single crack initiation sites were found in the CR and SR motions, while three crack initiation sites were typical in the ± 45(o) /10rc/+7(o) motion.

CONCLUSIONS

Fatigue life increased with decreasing reciprocating amplitude in stationary reciprocation. A progressive reciprocating operation with ± 45(o) /10rc/+7(o) motion led to significant fatigue life enhancement and multiple fatigue crack initiation in NiTi endodontic instruments.

The increase of the functional entropy of the human brain with age

We use entropy to characterize intrinsic ageing properties of the human brain. Analysis of fMRI data from a large dataset of individuals, using resting state BOLD signals, demonstrated that a functional entropy associated with brain activity increases with age. During an average lifespan, the entropy, which was calculated from a population of individuals, increased by approximately 0.1 bits, due to correlations in BOLD activity becoming more widely distributed. We attribute this to the number of excitatory neurons and the excitatory conductance decreasing with age. Incorporating these properties into a computational model leads to quantitatively similar results to the fMRI data. Our dataset involved males and females and we found significant differences between them. The entropy of males at birth was lower than that of females. However, the entropies of the two sexes increase at different rates, and intersect at approximately 50 years; after this age, males have a larger entropy.

Docosahexaenoic Acid Promotes Dopaminergic Differentiation in Induced Pluripotent Stem Cells and Inhibits Teratoma Formation in Rats with Parkinson-Like Pathology

Parkinson's disease (PD) is a neurodegenerative disorder characterized by the degeneration of dopaminergic (DA) neurons in the midbrain. Induced pluripotent stem (iPS) cells have shown potential for differentiation and may become a resource of functional neurons for the treatment of PD. However, teratoma formation is a major concern for transplantation-based therapies. This study examined whether functional neurons could be efficiently generated from iPS cells using a five-step induction procedure combined with docosahexaenoic acid (DHA) treatment. We demonstrated that DHA, a ligand for the RXR/Nurr1 heterodimer, significantly activated expression of the Nurr1 gene and the Nurr1-related pathway in iPS cells. DHA treatment facilitated iPS differentiation into tyrosine hydroxylase (TH)-positive neurons in vitro and in vivo and functionally increased dopamine release in transplanted grafts in PD-like animals. Furthermore, DHA dramatically upregulated the endogenous expression levels of neuroprotective genes ( Bcl-2, Bcl-xl, brain-derived neurotrophic factor, and glial cell-derived neurotrophic factor) and protected against 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced apoptosis in iPS-derived neuronal precursor cells. DHA-treated iPS cells significantly improved the behavior of 6-hydroxydopamine (6-OHDA)-treated PD-like rats compared to control or eicosapentaenoic acid-treated group. Importantly, the in vivo experiment suggests that DHA induces the differentiation of functional dopaminergic precursors and improves the abnormal behavior of 6-OHDA-treated PD-like rats by 4 months after transplantation. Furthermore, we found that DHA treatment in iPS cell-grafted rats significantly downregulated the mRNA expression of embryonic stem cell-specific genes (Oct-4 and c-Myc) in the graft and effectively blocked teratoma formation. Importantly, 3 Tesla-magnetic resonance imaging and ex vivo green fluorescence protein imaging revealed that no teratomas were present in transplanted grafts of DHA-treated iPS-derived DA neurons 4 months after implantation. Therefore, our data suggest that DHA plays a crucial role in iPS differentiation into functional DA neurons and that this approach could provide a novel therapeutic approach for PD treatment.

In vivo evaluation of demyelination and remyelination in a nerve crush injury model

Nerves of the peripheral nervous system have, to some extent, the ability to regenerate after injury, particularly in instances of crush or contusion injuries. After a controlled crush injury of the rat sciatic nerve, demyelination and remyelination are followed with functional assessments and imaged both ex vivo and in vivo over the course of 4 weeks with video-rate coherent anti-Stokes Raman scattering (CARS) microscopy. A new procedure compatible with live animal imaging is developed for performing histomorphometry of myelinated axons. This allows quantification of demyelination proximal and remyelination distal to the crush site ex vivo and in vivo respectively.

Ultrasound-assisted percutaneous catheterization of the axillary vein for totally implantable venous access device

BACKGROUND

Placing a totally implantable venous access device (TIVAD) using the classical subclavian vein puncture method carries the risk of certain complications including hemothorax, pneumothorax and pinch-off syndrome. We set out to determine whether percutaneous axillary vein catheterization can decrease the incidence of these complications.

METHOD

This is a prospective, observational, uni-institutional study. We analyzed the outcome of 113 TIVADs performed by ultrasound-assisted percutaneous axillary vein catheterization from Jun. 2008 to Dec. 2008. Junior residents novice to subclavian and axillary vein catheterization performed the procedures. Insertion and indwelling catheter complications were recorded.

RESULT

In our study population, 100% of TIVAD placements were successful. 27 patients (23.9%) required 3 or more repeated punctures; only one patient (0.9%) had clinically insignificant pneumothorax. Neither arterial puncture nor brachial plexus injury was recorded in our study.

CONCLUSION

Ultrasound-assisted percutaneous axillary vein catheterization for TIVAD is a safe and relatively simple method for inexperienced operators.

Monomeric chlorophyll a enol: Evidence for its possible role as the primary electron donor in photosystem I of plant photosynthesis

The chlorophyll a (Chl a) special-pair model of the primary donor of photosystem I (P700) does not account in a completely adequate fashion for the magnetic resonance properties observed for P700(+). Moreover, P700 is at least 420 mV easier to oxidize than is Chl a in vitro. Neither Chl a dimer formation nor selective ligation of Chl a can account for this potential difference. Enolization of the Chl a ring V beta-keto ester results in a very different pi electronic structure. The Chl a enol can be trapped as a silyl enol ether. In addition, the enol analog 9-desoxo-9,10-dehydro-Chl a can be prepared. Both the trapped enol and its 9-H analog are approximately 350 mV easier to oxidize than Chl a. The ESR spectrum of the cation radical consists of a single 6.1-G gaussian line that is line narrowed relative to that of Chl a(+) in a manner similar to P700(+). Electron-nuclear double resonance (ENDOR) spectroscopy resolves only a 3.5-MHz hyperfine splitting for the 3-methyl-group. The remaining splittings are all less than 3.5 MHz. The second moment of the ESR line of fully (13)C-enriched 9-desoxo-9,10-dehydro-Chl a(+) agrees with that of [(13)C]P700(+) to within 10%. Application of the special-pair model to the [(13)C]P700(+) second-moment data yields a 100% error. Ab initio molecular orbital calculations on ethyl chlorophyllide a enol cation bear out the ESR and ENDOR data. We conclude that a monomeric Chl a enol model provides a better description of the magnetic resonance parameters and oxidation potential of P700 than a Chl a special-pair model.

Clinical trial: percutaneous acetic acid injection vs. percutaneous ethanol injection for small hepatocellular carcinoma--a long-term follow-up study

BACKGROUND

The long-term outcome of percutaneous acetic acid injection (PAI) and percutaneous ethanol injection (PEI) for treating small hepatocellular carcinoma (HCC) remains unclear.

AIM

To compare the long-term outcome of PAI vs. PEI for treating small HCC.

METHODS

From July 1998 to July 2004, 125 patients with small HCC were enrolled. Seventy patients receiving PAI and 55 patients receiving PEI were enrolled. There were no significant differences in the clinical characteristics between the two groups. Tumour recurrence and survival rates were assessed.

RESULTS

Mean follow-up time was 43 months. The local recurrence rate and new tumour recurrence rate were similar between the PAI and PEI groups. The PAI group had significantly better survival than the PEI group (P = 0.027). Multivariate analysis revealed that PAI was the significant factor associated with overall survival [PAI vs. PEI, RR: 0.639, 95% CI: (0.419-1.975), P = 0.038]. The treatment sessions required to achieve complete tumour necrosis were significantly fewer in the PAI group than in the PEI group (2.4 +/- 1.0 vs. 2.9 +/- 1.3, P = 0.018).

CONCLUSION

Percutaneous acetic acid injection required fewer treatment sessions than PEI and provided better survival after long-term follow-up.

Direct effect of statins on homocysteine-induced endothelial adhesiveness: potential impact to human atherosclerosis

BACKGROUND

Although homocysteine (HCY) is a risk factor for cardiovascular diseases, recent clinical trials failed to show the benefits by reducing plasma HCY. Alternative strategy with 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors, statins, might be feasible. This study investigated HCY-induced endothelial adhesiveness with mononuclear cells (MNCs) from patients with coronary artery disease (CAD). The direct endothelial protective effects of statins were also examined.

MATERIALS AND METHODS

Circulating MNCs were isolated from 14 stable CAD patients and 7 age- and gender-matched healthy subjects. Superoxide production of MNCs was determined by Ultra-weak and luminol-enhanced chemiluminescence. Human aortic endothelial cells (HAECs) were used for endothelial adhesiveness to MNCs or U937 human monocytic cells. Endothelial expression of vascular cell adhesion molecule-1 (VCAM-1) and intercellular adhesion molecule-1 (ICAM-1) were examined by Western blot.

RESULTS

Superoxide production of MNCs and plasma HCY and high-sensitive CRP levels were significantly increased in CAD patients than in healthy subjects. Stimulation with HCY enhanced the endothelial adhesiveness to MNCs from CAD patients or to U937 cells in a dose-dependent manner, whereas it was obscure with MNCs from healthy subjects. HCY stimulated endothelial VCAM-1 but not ICAM-1 expression in a dose-dependent manner. Monoclonal antibodies to VCAM-1 attenuated HCY-induced endothelial adhesiveness. Simvastatin or pravastatin significantly reduced HCY-induced VCAM-1 expression and endothelial adhesiveness to MNCs from CAD patients.

CONCLUSION

Circulating MNCs were activated in CAD patients, which was critical to HCY-induced endothelial adhesiveness. Statins could directly reduce HCY-induced endothelial-MNC adhesion via VCAM-1 inhibition, suggesting its potential implication in HCY-related atherosclerosis disease.

Antioxidant and pro-oxidant properties of chlorhexidine and its interaction with calcium hydroxide solutions

AIM

To evaluate the antioxidant and pro-oxidant properties of chlorhexidine (CHX).

METHODOLOGY

The scavenging and generation of reactive oxygen species (ROS) by CHX in the presence or absence of saturated Ca(OH)(2) solutions was evaluated. The reaction emitted chemiluminescence in the presence of lucigenin thus was determined by a luminometer to evaluate the levels of ROS production. Changes in DNA conformation were analysed by agarose gel electrophoresis. Paired Student's t-test was used to compare the difference between groups.

RESULTS

Chlorhexidine (0.00002-0.02%) effectively scavenged 56-88% of the superoxide radicals generated by the xanthine/xanthine oxidase reaction. Through analysis of PUC18 DNA conformation changes, CHX was shown to be a mild scavenger of hydroxyl radicals generated by H(2)O(2) plus FeCl(2). However, CHX (>0.083%) decreased the mobility of PUC18 plasmid DNA with potential production of DNA-DNA cross-link and severe DNA breaks (presence of DNA smear) at further higher concentrations. Furthermore, CHX induced ROS production including H(2)O(2) and superoxide radicals in 0.1N NaOH (pH = 12.76) or Ca(OH)(2) (pH = 12.5) solutions.

CONCLUSION

Chlorhexidine exhibited both antioxidant and pro-oxidant properties under different conditions. These events are possibly involved in the killing of root canal and periodontal microorganisms when CHX and Ca(OH)(2) were used in combination or separately. Potential genotoxicity and tissue damage when extruded into the periradicular tissue and at higher concentrations should be considered during periodontal and endodontic practice.

Effects of simvastatin withdrawal on serum matrix metalloproteinases in hypercholesterolaemic patients

BACKGROUND

Serum matrix metalloproteinase (MMP) levels have been related to clinical outcomes in patients with coronary artery disease. Though statin treatment might reduce serum MMPs the change of levels after statin withdrawal remains obscure.

MATERIALS AND METHOD

Sixty-one consecutive hypercholesterolaemic patients whose lipid profiles had been well controlled by regular simvastatin (20 mg day(-1)) treatment for more than 6 months were enrolled. Statin was discontinued after their lipid profiles reached the treatment goal of the ATP-III guideline. The lipid profiles, serum MMP-2, MMP-3 and MMP-9, tissue inhibitor of MMP and highly sensitive C-reactive protein (hsCRP) levels were measured on the day of simvastatin withdrawal and 120 days later. A further 50 hyperlipidaemia patients who had never received statin treatment (positive control group) and 28 healthy patients with normal lipid profiles (negative control group) were also studied as control groups.

RESULTS

While the lipid profiles had been normalized, the levels of serum inflammatory markers were still higher in hypercholesterolaemic patients than in the healthy subjects. Up to 120 days after statin withdrawal there was no coronary event, but the lipid profiles and serum hsCRP levels had significantly rebounded in study patients. However, serum MMP-2 and MMP-9 levels remained unchanged and the MMP-3 level was even further reduced after statin withdrawal (115.04 +/- 84.54 vs. 92.71 +/- 66.71 ng mL(-1), P = 0.022). Moreover, the amplitudes of variation (%) of each parameter including MMPs, TIMP, hsCRP and lipid profiles after statin withdrawal were inversely correlated to their respective baseline levels before withdrawal (r = -0.702 to -0.284; P < 0.005).

CONCLUSIONS

The effects of short-term discontinuation of statin were different on serum hsCRP and MMPs levels in hypercholesterolaemic patients. While lipid profiles and serum hsCRP level had rebounded the serum MMPs levels were still unchanged, or even reduced, suggesting the prolonged effect of statin treatment, especially on serum MMP-3 level up to 120 days after simvastatin withdrawal. Further work is required to clarify the situation both in terms of these serum markers and clinical effects.

Plasma matrix metalloproteinase-3 level is an independent prognostic factor in stable coronary artery disease

BACKGROUND

Recent evidence suggests the important role of matrix metalloproteinases (MMPs) in the progression of atherosclerosis and development of clinical events. We assessed the prognostic value of different plasma MMPs in patients with stable coronary artery disease (CAD).

MATERIALS AND METHODS

A total of 165 consecutive nondiabetic patients with angiographically significant CAD (n = 150) or normal coronary angiograms despite exercise-induced myocardial ischemia (cardiac syndrome X, n = 15) and 17 normal subjects were evaluated. In each subject, plasma inflammatory markers including high sensitivity C-reactive protein (hsCRP) and MMP-2, 3 and 9 were measured. In CAD patients, major cardiovascular events including cardiac death, nonfatal myocardial infarction, unscheduled coronary revascularization and hospitalization as a result of unstable angina were prospectively followed up for more than 6 months.

RESULTS

Plasma levels of MMPs were significantly higher in CAD patients than in those with cardiac syndrome X and in normal subjects (MMP-2: 914.76 +/- 13.20 vs. 830.79 +/- 31.95 vs. 783.08 +/- 28.40 ng mL(-1), P = 0.002; MMP-3: 129.59 +/- 4.21 vs. 116.86 +/- 8.09 vs. 91.71 +/- 9.55 ng mL(-1), P = 0.011; MMP-9: 31.42 +/- 2.84 vs. 11.40 +/- 5.49 vs. 6.71 +/- 2.89 ng mL(-1), P = 0.006). In CAD patients, there were 48 major cardiovascular events during a mean follow-up period of 17.74 +/- 0.85 months. The numbers of diseased vessels (HR = 2.19, 95% CI 1.20-1.02, P = 0.011), plasma hsCRP (HR = 2.21, 95% CI 1.18-4.11, P = 0.013) and MMP-3 level (HR = 2.46, 95% CI = 1.15-5.28, P = 0.021) were associated with the development of cardiovascular events. However, only the plasma MMP-3 level was an independent predictor of the adverse events in CAD patients (HR = 2.47, 95% CI 1.10-5.54, P = 0.028).

CONCLUSIONS

Plasma MMP levels were increased in CAD patients. Plasma MMP-3 level, rather than hsCRP, was an independent prognostic marker for future cardiovascular events, suggesting its potential role in risk stratification and clinical management of stable CAD.

[Selective RPE laser treatment with a scanned cw laser beam in rabbits]

BACKGROUND

Selective RPE laser therapy with sparing of the neurosensory layer is possible by applying repetitive microsecond laser pulses. Macular diseases such as diabetic maculopathy, soft confluent drusen due to age-related macular degeneration or central serous chorioretinopathy were shown to be treated successfully-without concurrent laser scotoma-by this technique. It was the goal of this study to show, if selectivity could also be achieved using a conventional green cw-laser by scanning the beam across the retina during irradiation.

MATERIAL AND METHODS

A cw-laser beam at 532 nm was coupled to a slitlamp via a single mode optical fiber. The spot (18 microm) was scanned across the retina of Dutch-belted rabbits through a contact lens using a two-dimensional acusto-optical deflector. The scan-field was 300 microm x 300 microm in size and consisted of six separate scan lines. The scanning speed was adjusted so as to produce 5 micros exposure at each absorber in the center of the scan line. The entire scan pattern was applied 100 times at each site at a frame rate of 100 Hz. Dose response curve was measured by variation of the laser power. ED(50)-thresholds for RPE damage were calculated by fluorescein angiographic leakage in irradiated areas after exposure to different laser intensities. The extent of selectivity was examined by light microscopy.

RESULTS

Clinically the selective laser-induced RPE defect was demonstrated by fluorescein angiographic leakage and concurrent absence of ophthalmoscopic visibility. The angiographic ED(50)-damage threshold was 161 mJ/cm(2) (66 mW). Ophthalmoscopic visibility was not noticed even with the maximum available radiant exposure of 438 mJ/cm(2) (180 mW). Thus the safety range between angiographic and ophthalmoscopic thresholds had a factor of at least 2.7. First histological examinations revealed selective RPE destruction with intact photoreceptors for irradiation at laser power levels 2 times above angiographic threshold.

CONCLUSION

Selective RPE targeting is feasible with a conventional green cw-laser when scanning the focused laser beam across the fundus with a speed such that every point in exposed RPE is irradiated for duration of 5 micros.

In vivo flow cytometer for real-time detection and quantification of circulating cells

An in vivo flow cytometer is developed that allows the real-time detection and quantification of circulating fluorescently labeled cells in live animals. A signal from a cell population of interest is recorded as the cells pass through a slit of light focused across a blood vessel. Confocal detection of the excited fluorescence allows continuous monitoring of labeled cells in the upper layers of scattering tissue, such as the skin. The device is used to characterize the in vivo kinetics of red and white blood cells circulating in the vasculatúre of the mouse ear. Potential applications in biology and medicine are discussed.

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.