Rapid and highly sensitive analysis of benzodiazepines and tandospirone in human plasma by automated on-line column-switching UFLC-MS/MS

A high-throughput method was developed for the detection of 31 benzodiazepine drugs and tandospirone in human plasma by on-line column-switching ultra-fast liquid chromatography-tandem mass spectrometry. Plasma samples (100 μl) spiked with the 32 drugs and oxazepam-d₅ (internal standard) were diluted with 300 μl of 13.3 mM ammonium acetate/acetonitrile (33:67, v/v). After centrifugation and filtration, the clear supernatant was injected directly onto the extraction column (Oasis HLB cartridge column). The following procedure was fully automated. The analytes retained on the extraction column were eluted by backflushing of the extraction column and introduced into an analytical column (SUMIPAX ODS D-Swifter column, 30 mm × 3.0 mm i.d.; particle size 2 μm) by column switching. Quantification was performed by multiple reaction monitoring with positive-ion electrospray ionization. Distinct peaks appeared for each drug and the internal standard on each channel within 7 min, including the extraction time. All drugs spiked into plasma showed recoveries of 83–95%. The regression equations for the 32 drugs showed excellent linearities in the range of 50–2000 pg/ml of plasma and the limits of detection ranged from 20 to 50 pg/ml. The lower and upper limits of quantitation were 50–100 ng/ml and 2000 pg/ml, respectively. Intra- and interday coefficients of variation for none of the drugs were greater than 13.6%. The accuracies of quantitation were 87–112%. The multiple reaction monitoring information-dependent acquisition of enhanced product ions method enabled the quantification and confirmation of diazepam, triazolam, and lorazepam obtained from actual plasma.     

Disputed case of homicide by smothering due to severe amitriptyline intoxication of the victim

We report a fatal case of a female for whom the forensic autopsy revealed injuries to the external respiratory orifices indicating smothering. Subsequent postmortem toxicological analysis confirmed heavy amitriptyline acute intoxication. The victim had serious psychological problems, was under long-term treatment with antidepressants and was a systematic alcohol abuser. Forensic autopsy determined damage to the external airways, along with multiple formal petechial hemorrhages (Tardieu) in various parts of the body. The presence of amitriptyline, nortriptyline and 10-hydroxynortriptyline was confirmed by GC–MS and quantified by HPLC in blood (7.0 μg/ml amitriptyline and 7.4 μg/ml nortriptyline). The cause of death was disputed between severe intoxication (poisoning or suicide attempt) and smothering due to controversial evidence.     

Diagnostic approach to drug-screening tests for fatal diabetic ketoacidosis: Forensic autopsy of a methamphetamine abuser

To diagnose the cause of death in autopsy cases, systematic examinations, such as macroscopic, pathological, biochemical, and toxicological are important. In this case report, drug examinations also gave very useful information to diagnose the cause of death, fatal diabetic ketoacidosis (DKA). A female methamphetamine abuser in her forties was found dead lying on a hotel bed. Diagnosing her cause of death was difficult only from the macroscopic findings because there was no fatal and/or serious injury or disease. On toxicological examination, acetone was detected at a high concentration (682 μg/mL in blood, 887 μg/mL in urine) using gas chromatography (GC). Using gas chromatography–mass spectrometry (GC–MS), methamphetamine was detected in the blood, urine, hair, and visceral organs; however, these concentrations were low. At the same time, GC–MS examination revealed a high glucose peak. From the results of the biochemical examination of urine, acetoacetic acid was 1940 μmol/L, β-hydroxybutyric acid was 14,720 μmol/L, and glucose was 4620 mg/dL. Histologically, Langerhans’ islets in the pancreas were fibrotic and atrophic, and no insulin-immunoreactive cells were observed. The subsequent police investigation also revealed that she had contracted diabetes mellitus type 1; therefore, we concluded that her cause of death was DKA, due to a lack of insulin injection.     

Development for the measurement of serum thiosulfate using LC–MS/MS in forensic diagnosis of H2S poisoning

Thiosulfate measurement is crucial to diagnosis of hydrogen sulfide (H₂S) poisoning in forensic toxicology. Although GC–MS method is currently regarded as a standard thiosulfate measurement, it requires complicated sample preparation prior to analysis. This study presents a simple, rapid, and highly sensitive method for the quantitative analysis of serum thiosulfate by using liquid chromatography–tandem mass spectrometry (LC–MS/MS). This method is based on selected reaction monitoring and has high sensitivity with a lower quantification limit of 0.5 μM. Precision and accuracy of this method meet the basic requirements for quantitative analysis (intra- and inter-day tests have a relative standard deviation of ⩽10.4%; range of analytical recovery is 94.3–102.6%). On the measurements of serum thiosulfate by our developed method, a thiosulfate concentration as 57.5 μM was detected clearly in the H₂S poisoning case comparing to the non poisoning case in which only a trace amount of thiosulfate was observed.     

Detection of imidacloprid in biological fluids in a case of fatal insecticide intoxication

Here, we describe a high-performance liquid chromatography/photodiode array detector method for the detection of imidacloprid in biological fluids in a case of suicide by ingestion of liquor mixed with Admire® Flowable insecticide (containing 20% imidacloprid). A plastic bottle containing a cloudy liquid (concentration of ethanol in the liquid was 150 mg/ml and that of imidacloprid was 50 mg/ml) was found near the decedent. The biological fluids collected at autopsy were prepared by deproteinization with acetonitrile. Zolpidem was used as an internal standard. The concentrations of imidacloprid in femoral blood and cerebrospinal fluid were 105 and 58.5 μg/ml, respectively. Ethanol was also detected in the samples, with concentrations of 1.0 mg/ml in femoral blood and 1.4 mg/ml in cerebrospinal fluid.     

The in vitro effect of antimicrobial photodynamic therapy with indocyanine green on Enterococcus faecalis: Influence of a washing vs non-washing procedure

IntroductionThe purpose of this study was to evaluate the in vitro effect of washing and non-washing of indocyanine green (ICG) as photosensitizer (PS) on bacterial count, biofilm formation, development and degradation of Enterococcus faecalis.MethodsThe anti-bacterial, anti-biofilm formation, anti-biofilm development and biofilm degradation of anti-microbial photodynamic therapy (aPDT) against E. faecalis was determined at concentrations of 3 to 2000 μg/mL of ICG, subject to 18 J/cm² dose of diode laser (808 nm) in washing and non-washing producers. Bacterial viability measurements and biofilm assays were evaluated by broth microdilution method and crystal violet assays, respectively.ResultsICG-mediated aPDT, using 25 to 2000 μg/mL and 50 to 2000 μg/mL showed significant reduction in E. faecalis growth when compared to the control in non-washing and washing producers, respectively (P < 0.05). Also, ICG-mediated aPDT showed a significantly inhibitory effect on biofilm formation of E. faecalis in concentration of 6 to 2000 μg/mL and 100 to 2000 μg/mL in non-washing and washing groups (P < 0.05). The biofilm development was inhibited by concentrations of 12 to 2000 μg/mL and 100 to 2000 μg/mL in non-washing and washing groups. The biofilm degradation increased from concentrations of 12 to 2000 μg/mL and 250 to 2000 μg/mL in non-washing and washing groups, respectively.ConclusionThis study shows that the application of ICG should be accompanied by laser irradiation without being washed out to achieve better result for bacterial count reduction and anti-biofilm effects.     

5-Aminolevulinic acid-based photodynamic therapy of chordoma: In vitro experiments on a human tumor cell line

BackgroundChordomas are very rare tumors of the skull base and the sacrum. They show infiltrating and destructive growth and are known to be chemo- and radio-resistant. After surgical resection, the recurrence rate is high and overall survival limited. As current adjuvant treatments are ineffective, new treatment concepts are urgently needed. 5-aminolevulinic acid-based photodynamic therapy (5-ALA based PDT) showed promising results for malignant gliomas. However, it is unknown so far, whether chordomas accumulate protoporphyrin IX (PPIX) after application of 5-ALA and whether they are sensitive to subsequent 5-ALA based PDT.MethodsThe immortalized human chordoma cells U-CH2 were used as in vitro model. After incubation for 4 h or 6 h with different 5-ALA concentrations, PPIX accumulation was determined by flow cytometry. To assess sensitivity to PDT, chordoma cells were incubated at 30.000 cells/well (high cell density) or 15.000 cells/well (low cell density) with graded doses of 5-ALA (0–50 μg/ml) in 96-well plates and subsequently exposed to laser light of 635 nm wavelength (18.75 J/cm²). Cell survival was measured 24 h after exposure to laser light using the WST-1 assay.ResultsU-CH2 cells dose-dependently accumulated PPIX (ANOVA; p < 0.0001). PPIX fluorescence was significantly higher, when cells were incubated with 5-ALA for 6 h compared to 4 h at higher 5-ALA concentrations (ANOVA/Bonferroni; p ≤ 0.05 for ≥ 30 μg/ml 5-ALA). For both cell densities, a 5-ALA dose-dependent decline in viability was observed (ANOVA; p < 0.0001). Viability was significantly lower at higher 5-ALA concentrations, when 30.000 cells/wells were treated compared to 15.000 cells/well (ANOVA/Bonferroni; p ≤ 0.001 for ≥ 30 μg/ml 5-ALA). LD50 was 30.25 μg/ml 5-ALA.ConclusionThe human UCH-2 cell line was a very useful in vitro model to study different effects of 5-ALA based PDT. For the first time, it could be shown that human chordoma cells may be destroyed by 5-ALA/PDT.     

Real-time monitoring of arsenic filtration by granular ferric hydroxide

Contamination of drinking water by arsenic is a serious public health issue in many parts of the world. One recent approach to this problem has been to filter out arsenic by use of granular ferric hydroxide (GFH), an adsorbent developed specifically for the selective removal of arsenic from water. Previous studies have documented the efficiency and high treatment capacity of this approach. We present a novel X-ray fluorescence method to monitor the accumulation of arsenic within a specially designed GFH column, as both a function of time (or water volume) and location along the column. Using a miniature X-ray tube and silicon PiN diode detector, X-ray fluorescence is used to detect characteristic X-rays of arsenic excited from within the GFH. Trials were performed using a water flow rate of approximately 1.5 L per hour, with an added arsenic concentration of approximately 1000 μg per litre. In this paper, trial results are presented and potential applications described.     

Efficacy of erythrosine and cyanidin-3-glucoside mediated photodynamic therapy on Porphyromonas gingivalis biofilms using green light laser

BackgroundThe purpose of this in vitro study was to evaluate the efficacy of erythrosine and cyanidin-3-glucoside as photosensitizers in PDT for the elimination of Porphyromonas gingivalis (P. gingivalis) biofilms.MethodsP. gingivalis biofilms were prepared from a chronic periodontitis subject. Erythrosine and cyanidin-3-glucoside were prepared and randomly allocated as follows: 110, 220, 330, and 440 μM erythrosine; 101, 202, 303, and 404 μM anthocyanin; and 440 μM erythrosine + 404 μM cyanidin-3-glucoside. There were 18 PDT experimental groups (non-irradiated/irradiated with a 532-nm green light diode laser at 1.29 J/cm² for 60 s). The 3 controls were grouped as follows: biofilms exposed to the photosensitizers alone, biofilms exposed to the laser alone, and biofilms exposed to 0.12% chlorhexidine. All sample groups were cultured at 1, 3 and 6 h after PDT and incubated in an anaerobic chamber at 37 °C for 4 days. The surviving fraction was calculated from the log₁₀ CFU/ml. The 330 and 440 μM erythrosine and the 440 μM erythrosine + 404 μM cyanidin-3-glucoside were mixed with spin traps (TEMPO, DMPO), and the electron spin resonance spectra were evaluated.ResultsThe log₁₀ CFU/ml measurements showed that the PDT groups with 330 μM or 440 μM erythrosine and 440 μM erythrosine + 404 μM cyanidin-3-glucoside had statistically significant differences from the other groups (one-way ANOVA and Bonferroni’s multiple comparison test, p- value ≤ 0.05).ConclusionsPDT using 330 μM erythrosine, 440 μM erythrosine or 440 μM erythrosine + 404 μM cyanidin-3-glucoside irradiated with the laser more effectively inhibited P. gingivalis in biofilms.     

Evaluation of antimicrobial photodynamic therapy with indocyanine green and curcumin on human gingival fibroblast cells: An in vitro photocytotoxicity investigation

Recent investigations have suggested that antimicrobial photodynamic therapy (aPDT) can be an alternative treatment for the management of periodontal infections. However, currently there is very limited data regarding the photocytotoxicity of this method on human gingival fibroblast (HuGu) cells.AimThe in vitro optimal concentrations of indocyanine green (ICG) and curcumin as photosensitizers (PSs) and the irradiation time of diode laser emission were evaluated by assessing the photocytotoxicity of the treatment on HuGu cells.Materials and methodMonolayers of HuGu cells were incubated with various final concentrations of ICG (500, 750, 1000, 1250, 1500, 1750, and 2000 μg/ml) and curcumin (3, 4, 5, 10, and 20 mM). Three exposure times of the diode laser (30 s, 60 s, and 2 × 30 s irradiation with an interval of 1 min between each) and one of exposure time of 5 min for LED were tested; cell viability was determined using neutral red assay. Chlorhexidine (CHX) as a gold standard antimicrobial agent for periodontal disease was considered as a control group.ResultsICG and curcumin significantly reduced HuGu cell viability at concentrations below 1000 μg/ml and 10 mM, respectively (P < 0.01). Cytotoxicity was higher when the cells were treated for 2 × 30 s irradiation with an interval of 1 min and then again exposed to the laser for 30 s (2% and 0.1%). CHX demonstrated no significant reduction in HuGu cell survival.ConclusionPhotocytotoxicity is influenced by PS concentration, exposure time of PS, and time of irradiation. High doses of ICG and curcumin with lowest exposure time of light source and without cytotoxic effects may be an effective strategy for aPDT as an alternative treatment for periodontal disease.     

An autopsy case of spontaneous esophageal perforation (Boerhaave syndrome)

A 45-year-old male, an alcohol addict with asthma, was found dead in his home, after several days of continued drinking. A forensic autopsy was performed 3 days after the discovery of his death in order to specify the cause of death.A longitudinal perforation penetrating all layers of the esophagus measuring 1.8 cm was present on the left wall approximately 2.0 cm from the gastroesophageal junction. There were 1900 mL of greenish to brownish turbid liquid in the left pleural cavity and 150 mL of greenish viscous liquid in the stomach. Histopathologically, an infiltration of numerous neutrophils was evident in the submucosa layer, proper muscular layer, and serous membrane of the esophagus, corresponding to the esophageal laceration. The serum C-reactive protein (CRP) concentration was determined to be 3.1 mg/dL. The alcohol concentrations were determined to be 1.49 mg/g in the right cardiac blood, 1.31 mg/g in the left cardiac blood, and 2.48 mg/g in urine.Based upon the autopsy and histopathological findings, as well as the biochemical and toxicological analyses, we concluded that the cause of death was respiratory failure by pleural effusion, resulting from spontaneous esophageal perforation. This was the first report of a spontaneous esophageal perforation eventually causing respiratory failure.     

Hair-zinc levels determination in Algerian psoriatics using Instrumental Neutron Activation Analysis (INAA)

Psoriasis is a multifactorial skin disease with an unknown etiology. Zinc has a positive impact on psoriasis. The aim of this study is to determine hair-zinc concentration in Algerian psoriatics. 58 psoriatics and 31 normal controls of both genders were selected. Hair zinc levels were determined using Instrumental Neutron Activation Analysis technique (INAA). Student's t-test and One-Way ANOVA were applied. The average zinc concentration for controls and patients were 152±53 μg/g and 167±52 μg/g respectively. They are not significantly different (p>0.05). Zn concentration for males and females controls and patients were 171±27 μg/g, 151±37 μg/g and 145±59 μg/g, 178±58 μg/g respectively. However, for females we have observed a significant difference (p<0.05).     

Energy efficiency and pulmonary artery flow after balloon pulmonary angioplasty for inoperable,chronic thromboembolic pulmonary hypertension: Analysis by phase-contrast MRI

PurposeThe aims of this study were to propose a new quantitative method for pulmonary artery (PA) flow energetics using phase-contrast magnetic resonance imaging (PC-MRI), and to investigate how balloon pulmonary angioplasty (BPA) impacts energetics in chronic thromboembolic pulmonary hypertension (CTEPH).Materials and methodsPC-MRI at 3-Teslar and with a flow sensitive gradient echo was used to examine energetics prior to and following BPA for 24 CTEPH patients. Stroke volume (m; ml) and mean velocity (V; mm/s) for the main pulmonary artery (PA), right PA, and left PA were calculated from a time-flow curve derived from PC-MRI. Based on the Bernoulli principle, PA energy was identified as 1/2 mV² (μj/kg), and energy loss was defined as the following equation “energy loss = main PA energy − (rt. PA energy + lt. PA energy)”.ResultsRight PA energy was significantly greater post-BPA than pre-BPA (61 ± 55 vs. 32 ± 40 μj/kg). There was no difference in main PA and left PA energies. Energy loss was significantly decreased post-BPA (18 ± 97 μj/kg) than pre-BPA (79 ± 125 μj/kg). An optimal cutoff of left PA energy of 45 μj/kg pre-BPA can be used to predict patients with mPAP ≥ 30 mmHg after BPA, with an area under the curve of 0.91, 78% sensitivity, and 92% specificity.ConclusionAnalysis of PA energetics using phase-contrast MRI demonstrates that BPA improves energy loss in CTEPH. In addition, BPA responses can be predicted by PA energy status pre-treatment.     

Hypoleptinaemia in extreme body mass models: The case of international rugby players

Leptinaemia has been poorly studied in athlete populations with the consequences of athletic hypoleptinaemia yet to be examined. Our aim was to determine if systemic leptinaemia is influenced in high body mass athletes. We recruited 24 rugby players (21.5 ± 4.7 years; 11.8 ± 2.9 h/week) and 26 controls (22.3 ± 3.1 years; 1.9 ± 1.4 h/week). BMD (whole body (WB), limbs, lumbar spine and non-dominant femur) and body composition (WB Lean Mass (LM) and FM) were measured by Dual X-ray Absorptiometry. Circulating levels of serum leptin (ng/ml), adiponectin (μg/ml), insulin (ng/ml), osteocalcin (ng/ml) and CTx (ng/ml) were assessed by ELISA assays. BMD were significantly higher in rugby players vs controls, at all bone sites, yet after adjustments for body mass index. They had significantly higher LM and FM but no differences in %FM. They had significantly higher osteocalcin but lower CTx, insulin and leptin concentrations. Leptin levels were strongly correlated to %FM (r = 0.85, p < 0.0001), as well as to absolute FM (r = 0.77, p = 0.0002), in the rugbymen group. Rugby practice was associated to a bone remodelling process in favour of bone formation. There was a significant hypoleptinaemia in our rugby players, while their percent FM was equivalent and absolute FM significantly higher than the control levels. These data suggest that leptin is under control of physical activity and not just fat mass.     

Evaluation of the antitumor effects of rilotumumab by PET imaging in a U-87 MG mouse xenograft model

IntroductionDysregulation of the hepatocyte growth factor (HGF)/MET pathway has been implicated in various cancers. Rilotumumab is an investigational, fully human monoclonal antibody that binds and neutralizes HGF. The purpose of this study was to evaluate the efficacy of rilotumumab in a U-87 MG mouse xenograft tumor model using ¹⁸ F-FDG and ¹⁸ F-FLT PET.MethodsU-87 MG tumor-bearing nude mice received rilotumumab or control IgG2. In the dose response study, increasing doses of rilotumumab (10, 30, 100, 300, or 500 μg) were administered, and mice were evaluated with ¹⁸ F-FDG PET at baseline and 7 days post-treatment. In the time course study, 300 μg of rilotumumab twice per week was used for the treatment, and mice were evaluated over 7 days using ¹⁸ F-FDG and ¹⁸ F-FLT PET.ResultsIn the dose response study, rilotumumab at doses of 300 and 500 μg was similarly effective against tumor growth. Treatment with 300 and 500 μg rilotumumab inhibited ¹⁸ F-FDG accumulation with significant decreases of ? 37% and ? 40% in the percent injected dose per gram of tissue (%ID/g), respectively. In the time course study, treatment with 300 μg rilotumumab inhibited ¹⁸ F-FDG and ¹⁸ F-FLT accumulation with a maximum %ID/g of ? 41% and ? 64%, respectively. No apparent differences between the use of either tracer to evaluate rilotumumab efficacy were observed.ConclusionsRilotumumab inhibited ¹⁸ F-FDG and ¹⁸ F-FLT accumulation as early as 2 and 4 days after treatment, respectively, in a mouse tumor model. Further studies to evaluate ¹⁸ F-FDG PET imaging as an early tumor response marker for rilotumumab are warranted. Rilotumumab is currently being tested in patients with MET-positive, advanced gastric and gastroesophageal cancer.     

Polyvinyl alcohol terminal chemoembolization for hepatocellular carcinoma with hepatic arteriovenous shunts: Safety,efficacy, and prognostic factors

PurposeTo evaluate the safety and efficacy of polyvinyl alcohol (PVA) terminal chemoembolization and to identify the prognostic factors associated with survival in hepatocellular carcinoma (HCC) patients with hepatic arteriovenous shunts (HAVS).Materials and methodsOf 133 patients’ managements were retrospectively analyzed. HAVS was classified into three types: slow-flow, intermediate-flow and high-flow. The size of the PVA used was determined following the scheme: slow-flow HAVS: 300–500 μm PVA; intermediate-flow HAVS: 500–710 μm PVA; high-flow HAVS: 710–1000 μm PVA. The HCCs with slow-flow and intermediate-flow HAVS were embolized by PVA plus chemotherapeutic agents lipiodol emulsion, while the high-flow HAVS were treated by PVA with chemotherapeutic agents. Survival curves were calculated by Kaplan-Meier method and compared by log-rank test. The influence of possible prognostic factors on survival were analyzed by multivariate Cox proportional-hazards method.ResultsThe median overall survival (OS) of 133 patients was 9.1 months. The median OS of the slow-flow type, intermediate-flow type and high-flow type patients were 10.8, 9.1 and 7.3 months, respectively. There was no statistically significant difference among different HAVS types (P = 0.239). The 30-day mortality was 3.8%. Cox multivariate survival analysis revealed that initial preoperative AFP value ≥ 400 ng/ml (HR = 2.105, P = 0.006) was an independent risk factor. While multiple embolization (HR = 0.482, P = 0.011), tumor remission (HR = 0.431, P = 0.041) and multimodality therapy (HR = 0.416, P = 0.004) were independent protection factors.ConclusionIt is safe and effective for HCCs with HAVS treated by terminal chemoembolization therapy with PVA plus chemotherapeutic agents lipiodol emulsion (or PVA plus chemotherapeutic agents). The HCCs with HAVS achieves good prognosis with multiple embolization, tumor remission and multimodality therapy, while achieves poor prognosis with inital preoperative high AFP value (≥400 ng/ml).     

Preparation of 99mTc-TRODAT-1 with high labeling yield in boiling water bath: A new formulation

A new formulation for preparation of ^99mTc-labeled tropane derivative, ^99mTc-TRODAT-1, which is useful as a potential CNS dopamine transporter imaging agent, was evaluated and characterized.Preparation of ^99mTc-TRODAT-1 was attained previously by a formulation in which vial has to be autoclaved at 121 °C for 30 min. It is highly desirable to further improve the preparation method by developing a simplified one vial formulation which will be labeled in boiling water bath (95 °C) for 15 min and a high labeling yield will be achieved. A formulation contained 10 μg of TRODAT-1, 20 μg tricine, 40 μg SnCl₂ and 20 mg manitol was prepared. Labeling was performed at 95 °C for 15 min and radiochemical analysis involved ITLC and HPLC methods. The stability of radioconjugate was checked in the presence of human serum at 37 °C up to 24 h.^99mTc-TRODAT-1 was prepared with a radiochemical purity of more than 95% and specific activity of 64.3 MBq/nmol. Biodistribution studies of this new formulation in rats revealed similar regional brain distribution as compared with those obtained with the previous preparation in which brain uptake was high in striatum and striatum to cerebellum ratio was high. Requiring no autoclave facility for labeling, this new formulation will significantly improve the using feasibility of this radiopharmaceutical in clinic.     

Biodistribution of a radiolabelled thermoresponsive polymer in mice

Drug delivery systems based on thermoresponsive polymers might serve as suitable carriers for local radiotherapy. We have, therefore, designed and synthesized a radioiodine-labellable thermoresponsive polymer. The polymer was synthesized by copolymerization of N-isopropylacrylamide with N-methacryloyl tyrosinamide in tetrahydrofuran, and then labelled by ¹³¹I. The solution of this labelled polymer in dimethylsulfoxide (4.4 MBq/ml; 1.8 wt% polymer) was applied to femoral muscle of male Balb/C mice (50 μl per animal). The biodistribution and excretion of radioactivity was followed in 2 h and 1, 7, 14, 28 and 42 d post injection (n=6 per time point).As expected, the labelled polymer was left on the application site (ca 90% 2 h post injection), decreasing slowly to ca 80% within 14 d. At 28 d post injection, ca 70% of the injected activity was still found on the application site, decreasing to ca 60% at 42 d. No organ-specific accumulation of the radioactivity released from the application site, including thyroid, was observed. Majority of the released radioactivity was excreted via urine and faeces. This preliminary study suggests that thermoresponsive polymers could be used as an effective delivery system for localized radiotherapy.     

Dependence of damage within 10 min to myocardial cells by a photodynamic reaction with a high concentration of talaporfin sodium outside cells in vitro on parameters of laser irradiation

BackgroundTo investigate the immediate occurrence of irreparable severe damage to myocardial cells up to 10 min after a photodynamic reaction with a high concentration of photosensitizer outside cells, we measured the damage response time and the parameters that govern the response time via rat myocardial Ca²⁺ concentration. In our proposed method for catheter ablation of tachyarrhythmia by photodynamic reaction, there are two components to the electrical conduction block: an immediate electrical conduction block of several tens of seconds to several minutes, and a permanent electrical conduction block.MethodsRat myocardial intracellular Ca²⁺ concentration changes before, during and after the photodynamic reaction with a high concentration of photosensitizer outside myocardial cells were continuously observed using a Fluo-4 AM Ca²⁺ probe. Talaporfin sodium with 663-nm excitation was used to induce the photodynamic reaction. Talaporfin concentration was 10–30 μg/ml, radiant exposure was 10–40 J/cm², and irradiance was 30–290 mW/cm². We evaluated the response time of irreparable severe damage to myocardial cells, according to Ca²⁺ concentration.ResultsThe response time of the defined severe damage occurrence to myocardial cells ranged from 200 to 500 s. The response time decreased with increasing irradiance and photosensitizer concentration, but exhibited no significant change with total radiant exposure.ConclusionsWe found that severe myocardial cell damage caused by a photodynamic reaction with a high concentration of photosensitizer outside cells occurred within a few minutes, which might be useful for catheter ablation for tachyarrhythmia that needs immediate response during the ablation procedure.