Subchronic toxicity study of indium-tin oxide nanoparticles following intratracheal administration into the lungs of rats.

OBJECTIVES: We aimed to analyze the subchronic toxicity and tissue distribution of indium after the intratracheal administration of indium-tin oxide nanoparticles (ITO NPs) to the lungs of rats. METHODS: Male Wistar rats were administered a single intratracheal dose of 10 or 20 mg In/kg body weight (BW) of ITO NPs. The control rats received only an intratracheal dose of distilled water. A subset of rats was periodically euthanized throughout the study from 1 to 20 weeks after administration. Indium concentrations in the serum, lungs, mediastinal lymph nodes, kidneys, liver, and spleen as well as pathological changes in the lungs and kidneys were determined. Additionally, the distribution of ionic indium and indium NPs in the kidneys was analyzed using laser ablation-inductively coupled plasma mass spectrometry. RESULTS: Indium concentrations in the lungs of the 2 ITO NP groups gradually decreased over the 20-week observation period. Conversely, the indium concentrations in the mediastinal lymph nodes of the 2 ITO groups increased and were several hundred times higher than those in the kidneys, spleen, and liver. Pulmonary and renal toxicities were observed histopathologically in both the ITO groups. Both indium NPs and ionic indium were detected in the kidneys, and their distributions were similar to the strong indium signals detected at the sites of inflammatory cell infiltration and tubular epithelial cells. CONCLUSIONS: Our results demonstrate that intratracheal administration of 10 or 20 mg In/kg BW of ITO NPs in male rats produces pulmonary and renal toxicities.

Hepatic, Metabolic, and Toxicity Evaluation of Repeated Oral Administration of SnS2 Nanoflowers in Mice.

Tin sulfide (SnS2) nanoflowers (NFs) with highly photocatalytic activity for wastewater treatment may lead to potential health hazards via oral routes of human exposure. No studies have reported the hepatic effects of SnS2 NFs on the metabolic function and hepatotoxicity. In this study, we examined the hepatic effects of the oral administration of SnS2 NFs (250-1000 mg/kg) to ICR mice for 14 days, with the particle size ranging from 50 to 200 nm. Serum and liver tissue samples were assayed using biochemical analysis, liver histopathology and metabolic gene expression. The different sizes of SnS2 NFs (250 mg/kg dose), such as 50, 80, and 200 nm, did not induce any adverse hepatic effect related to biochemical parameters or histopathology in the treated mice compared with controls. The oral administration of 50-nm SnS2 NFs at doses of 250, 500, and 1000 mg/kg for 14 days produced dose-dependent hepatotoxicity and inflammatory responses in treated mice. Furthermore, the expression of metabolic genes in the liver tissues was altered, supporting the SnS2 NF-related hepatotoxic phenotype. The oral administration of SnS2 NFs also produced abnormal microstructures in the livers of the treated mice. Taken together, these data indicate that the increased risk of hepatotoxicity in SnS2 NF-treated mice was independent of the particle size but was dependent on their dose. The no-observed-adverse effect level was <250 mg/kg for the 50-nm SnS2 NFs. Our study provides an experimental basis for the safe application of SnS2 NFs.

Frequency of Application of AmF/NaF/SnCl2 Solution and Its Potential in Inhibiting the Progression of Erosion in Human Dental Enamel - An In Vitro Study.

PURPOSE: To evaluate whether increasing the frequency of its use can enhance the protective effect of AmF/NaF/SnCl2 solution against dental erosion. MATERIALS AND METHODS: Sixty human enamel samples were obtained from sound human third molars, and after the formation of incipient erosive lesions (1% citric acid, pH 4.0, for 3 min), they were divided into five treatment groups (n = 12): G1 - deionised water (negative control); G2 - NaF solution (positive control) once a day; G3 - NaF solution (positive control) twice a day; G4 - AmF/NaF/SnCl2 solution once a day; G5 - AmF/NaF/SnCl2 solution twice a day. The samples were then subjected to 5 days of erosive cycling through 6 daily immersions (2 min each) in citric acid solution (0.05 M, pH 2.6). At the end of erosive cycling, surface wear was determined by means of optical profilometry. RESULTS: One-way ANOVA showed that the surface wear was affected by surface treatments (p < 0.001). Tukey's test showed no difference between the groups in which NaF was applied once or twice, but they showed limited reduction in wear compared to the deionised water group (G1). In the groups treated with the AmF/NaF/SnCl2 solution, there was a statistically significant difference between one and two application times (p < 0.001). Although both demonstrated statistically significantly reduced tissue loss, increasing the frequency increased its anti-erosive potential. CONCLUSION: The AmF/NaF/SnCl2 solution proved to be effective in reducing dental enamel surface loss and its use twice a day potentiated its anti-erosive effect.

Frequency of Application of AmF/NaF/SnCl2 Solution and Its Potential in Controlling Human Enamel Erosion Progression: An in situ Study.

Although several studies have demonstrated the efficacy of AmF/NaF/SnCl2 solution in inhibiting dental erosion progression, measures for further improvement in its effectiveness are paramount. Thus, this in situ study evaluated whether the protective effect promoted by the AmF/NaF/SnCl2 solution would be enhanced by increasing its frequency of use. The study was conducted with 12 volunteers, a 4-phase (5 days each) randomized, crossover model. Extraoral erosive challenges (0.5% citric acid, pH 2.6, 6 × 2 min/day) and rinsing protocol (1 or 2 × 2 min/day) were performed. Before the in situ phase, human enamel samples were subjected to an in vitro surface softening (1% citric acid, pH 4.0, for 3 min). Four treatment protocols were tested using samples in replicas (n = 12): group G1 - deionized water (negative control); G2 - NaF solution (positive control, 500 ppm F-, pH 4.5); G3 - AmF/NaF/SnCl2 solution (500 ppm F-, 800 ppm Sn2+, pH 4.5) once a day; G4 - AmF/NaF/SnCl2 solution twice a day. Tissue loss and morphological changes were determined by optical profilometry (n = 12) and scanning electron microscopy (n = 3) analysis, respectively. Data were statistically analyzed by ANOVA with subsequent pairwise comparison of treatments. Tissue loss means (±SD in µm) for each treatment protocol and statistical differences were found as follows: G1 4.55 ± 2.75, G2 4.59 ± 2.13, G3 2.64 ± 1.55, and G4 1.34 ± 1.16. Although there was no difference between the 2 AmF/NaF/SnCl2 solution application regimens (once or twice a day), application of the product twice a day was the only treatment that was able to control erosion progression, differing from the control groups.

Endocytosis of indium-tin-oxide nanoparticles by macrophages provokes pyroptosis requiring NLRP3-ASC-Caspase1 axis that can be prevented by mesenchymal stem cells.

The biological effects of indium-tin-oxide (ITO) are of considerable importance because workers exposed to indium compounds have been diagnosed with interstitial lung disease or pulmonary alveolar proteinosis; however, the pathophysiology of these diseases is undefined. Here, mice intraperitoneally inoculated with ITO-nanoparticles (ITO-NPs) resulted in peritonitis dependent in NLRP3 inflammasome, with neutrophils recruitment and interleukin-1ß (IL-1ß) production. Withal peritoneal macrophages exposed ex vivo to ITO-NPs caused IL-1ß secretion and cytolysis. Further, alveolar macrophages exposed to ITO-NPs in vitro showed ITO-NP endocytosis and production of tumor necrosis factor-α (TNF-α) and IL-1ß, ensued cell death by cytolysis. This cell death was RIPK1-independent but caspase1-dependent, and thus identified as pyroptosis. Endocytosis of ITO-NPs by activated THP-1 cells induced pyroptosis with IL-1ß/TNF-α production and cytolysis, but not in activated THP-1 cells with knockdown of NLRP3, ASC, or caspase1. However, exposing activated THP-1 cells with NLRP3 or ASC knockdown to ITO-NPs resulted in cell death but without cytolysis, with deficiency in IL-1ß/TNF-α, and revealing features of apoptosis. While, mesenchymal stem cells (MSCs) co-cultured with macrophages impaired both inflammation and cell death induced by ITO-NPs. Together, our findings provide crucial insights to the pathophysiology of respiratory diseases caused by ITO particles, and identify MSCs as a potent therapeutic.

Tailoring 99mTc-Macroaggregated Albumin Administration to Optimize Patient Dose Reduction.

UNLABELLED: In the ever-changing field of nuclear medicine, best-practice considerations cannot simply go unchallenged for months and years, with the need to minimize radiation exposure to patients highlighted in "as low as reasonably achievable" principles. The Australian Radiation Protection and Nuclear Safety Agency reports that the dose for (99m)Tc-macroaggregated albumin ((99m)Tc-MAA) administered should be 180-200 MBq. An objective of imaging in pulmonary embolism, or indeed any diagnostic procedure involving radiation, is to minimize radiation exposure without sacrificing image quality and diagnostic accuracy. The amount of radiation involved must be considered together with imaging protocols. Our aim was to reduce the amount of (99m)Tc-MAA administered without compromising the diagnostic quality of the scan. METHODS: To achieve a ventilation-to-perfusion ratio of 1:4, we ventilated the patient as per standard protocol and then placed intravenous access into the patient. For the perfusion component, 180-200 MBq were prepared in a 2-mL injection. Aliquots of 0.5 mL of (99m)Tc-MAA were administered every 30 s followed by a 5-mL saline flush until the required ventilation-to-perfusion ratio was achieved. RESULTS: With this protocol, the average administered dose was 105 ± 20.7 MBq (vs. 180 ± 5.3 MBq, P < 0.0001). CONCLUSION: By individually tailoring the administered dose, diagnostic quality is maintained while achieving a significant dose reduction.

Tissue distribution of indium after repeated intratracheal instillations of indium-tin oxide into the lungs of hamsters.

OBJECTIVES: The aim of this study was to analyze the tissue distribution of indium after intratracheally instilling indium-tin oxide (ITO) into the lungs of hamsters. METHODS: Male Syrian hamsters received an intratracheal dose of 3 mg/kg or 6 mg/kg of ITO particles containing 2.2 mg/kg or 4.5 mg/kg of indium, twice weekly for 8 weeks. In parallel, control hamsters received only an intratracheal dose of distilled water. A subset of hamsters was euthanized periodically throughout the study from 8 up to 78 weeks after the final instillation. The distribution of indium in the lungs, liver, kidneys and spleen, as well as pathological changes in the liver, kidneys, and spleen, was determined. RESULTS: The contents of indium in the lungs in the two ITO groups gradually decreased over the 78-week observation period, with elimination half-lives of approximately 142 weeks for the 3 mg/kg ITO group and 124 weeks for the 6 mg/kg ITO. The indium concentrations in the liver, kidneys, and spleen gradually increased throughout the observation period. Although foci of the lesions were observed histopathologically in the extrapulmonary organs among the two ITO groups, the control group showed similar lesions. CONCLUSIONS: The results clearly demonstrate that the clearance of indium from the body is extremely slow after intratracheal instillation in hamsters.

Inorganic tin compounds do not induce micronuclei in human lymphocytes in the absence of metabolic activation.

The genotoxic evaluation (in vitro analysis) of a series of eight inorganic tin(II) and tin(IV) compounds [tin(II) acetate, tin(II) chloride, tin(II) ethylhexanoate, tin(II) oxalate, tin(II) oxide, tin(IV) acetate, tin(IV) chloride and tin(IV) oxide], for the detection of micronuclei in human blood lymphocytes, was performed in the absence of metabolic activation by the cytokinesis-block micronucleus assay. Human lymphocytes were treated for over one cell cycle (31 hours), with concentrations ranging from 1 to 75 µM (1, 5, 10, 20, 50 and 75 µM), of tin(II) and tin(IV) salts dissolved in dimethyl sulfoxide. The above-listed concentrations cover the values that have been detected in humans with no occupational exposure to tin compounds. The experimental results show the absence of genotoxicity for all inorganic compounds tested in the specific concentrations and experimental conditions. Cytotoxic effects of tin(II) and tin(IV) compounds were evaluated by the determination of cytokinesis block proliferation index and cytotoxicity percentage. Our observations on the cytotoxicity pattern of the tested tin(II) and tin(IV) compounds indicate that they are cytotoxic in several tested concentrations to human lymphocytes treated in vitro. The observed differences in cytotoxicity of each tested compound might reflect differences in their chemical structure.

Increased HO-1 levels ameliorate fatty liver development through a reduction of heme and recruitment of FGF21.

OBJECTIVE: Obese leptin deficient (ob/ob) mice are a model of adiposity that displays increased levels of fat, glucose, and liver lipids. Our hypothesis is that HO-1 overexpression ameliorates fatty liver development. METHODS: Obese mice were administered cobalt protoporphyrin (CoPP) and stannic mesoporphyrin (SnMP) for 6 weeks. Heme, HO-1, HO activity, PGC1α, FGF21, glycogen content, and lipogenesis were assessed. RESULTS: CoPP administration increased hepatic HO-1 protein levels and HO activity, decreased hepatic heme, body weight gain, glucose levels, and resulted in decreased steatosis. Increased levels of HO-1 produced a decrease in lipid droplet size, Fatty acid synthase (FAS) levels involving recruitment of FGF21, PPARα, and Glut 1. These beneficial effects were reversed by inhibition of HO activity. CONCLUSION: Increased levels of HO-1 and HO activity reduced the levels of obesity by reducing hepatic heme and lipid accumulation. These changes were manifested by decreases in cellular heme, increases in FGF21, glycogen content, and fatty liver. The beneficial effect of HO-1 induction results from an increase in PPARα and FGF21 levels and a decrease in PGC1α, levels they were reversed by SnMP. Low levels of HO-1 and HO activity are responsible for fatty liver.

Efficacy of fluoride compounds and stannous chloride as erosion inhibitors in dentine.

The aim of this study was to evaluate the anti-erosive effects of different fluoride compounds and one tin compound in the context of the complex pathohistology of dentine erosion, with particular emphasis on the role of the organic portion. Samples were subjected to two experiments including erosive acid attacks (0.05 molar citric acid, pH 2.3; 6 x 2 min/day) and applications (6 x 2 min/day) of the following test solutions: SnCl(2) (815 ppm Sn), NaF (250 ppm F), SnF(2) (250 ppm F, 809 ppm Sn), amine fluoride (AmF, 250 ppm F), AmF/NaF (250 ppm F), and AmF/SnF(2) (250 ppm F, 409 ppm Sn). The demineralised organic fraction was enzymatically removed either at the end of the experiment (experiment 1) or continuously throughout the experiment (experiment 2). Tissue loss was determined profilometrically after 10 experimental days. In experiment 1, the highest erosive tissue loss was found in the control group (erosion only); the AmF- and NaF-containing solutions reduced tissue loss by about 60%, reductions for SnCl(2), AmF/SnF(2), and SnF(2) were 52, 74 and 89%, respectively. In experiment 2, loss values generally were significantly higher, and the differences between the test solutions were much more distinct. Reduction of tissue loss was between 12 and 34% for the AmF- and NaF-containing preparations, and 11, 67 and 78% for SnCl(2), AmF/SnF(2), and SnF(2), respectively. Stannous fluoride-containing solutions revealed promising anti-erosive effects in dentine. The strikingly different outcomes in the two experiments suggest reconsidering current methodologies for investigating anti-erosive strategies in dentine.

Sentinel lymph node identification with radiopharmaceuticals in patients with breast cancer: a comparison of 99mTc-tin colloid and 99mTc-phytate efficiency.

Sentinel lymph node biopsy with lymphoscintigraphy has become the standard method for the detection of axillary lymph node metastasis in breast cancer patients. However, there is no standardized radiopharmaceutical. For the detection of axillary lymph node metastasis by lymphoscintigraphy and sentinel node biopsy in patients with breast cancer, we compared the results between subareolar injection of (99m)Tc-tin colloid and injection of (99m)Tc-phytate. This study included 516 breast cancer patients who underwent surgery between 2001 and 2010. Among the 516 patients, (99m)Tc-tin colloid (37-185 MBq) was administered to 412 patients by subareolar injection, and (99m)Tc-phytate (37-185 MBq) was injected in 104 patients. Lymphoscintigraphy was performed with the patients in the supine position, and sentinel node identification was performed by hand-held gamma probe during surgery. Among 412 patients with (99m)Tc-tin colloid, the sentinel node was identified by lymphoscintigraphy in 364 cases (88.3%) and by a gamma probe in 369 cases (89.6%). Among 104 patients with (99m)Tc-phytate, 101 cases (97.1%) were identified by lymphoscintigraphy and 101 cases (97.1%) were identified by a gamma probe. The identification rates by lymphoscintigraphy and gamma probe were superior with (99m)Tc-phytate, as compared with (99m)Tc-tin colloid, with a statistically significant difference (P < 0.05 for both methods). (99m)Tc-phytate is a better choice than (99m)Tc-tin colloid for identification of the sentinel node in breast cancer patients.

Endonuclease IV is the main base excision repair enzyme involved in DNA damage induced by UVA radiation and stannous chloride.

Stannous chloride (SnCl(2)) and UVA induce DNA lesions through ROS. The aim of this work was to study the toxicity induced by UVA preillumination, followed by SnCl(2) treatment. E. coli BER mutants were used to identify genes which could play a role in DNA lesion repair generated by these agents. The survival assays showed (i) The nfo mutant was the most sensitive to SnCl(2); (ii) lethal synergistic effect was observed after UVA pre-illumination, plus SnCl(2) incubation, the nfo mutant being the most sensitive; (iii) wild type and nfo mutants, transformed with pBW21 plasmid (nfo(+)) had their survival increased following treatments. The alkaline agarose gel electrophoresis assays pointed that (i) UVA induced DNA breaks and fpg mutant was the most sensitive; (ii) SnCl(2)-induced DNA strand breaks were higher than those from UVA and nfo mutant had the slowest repair kinetics; (iii) UVA + SnCl(2) promoted an increase in DNA breaks than SnCl(2) and, again, nfo mutant displayed the slowest repair kinetics. In summary, Nfo protects E. coli cells against damage induced by SnCl(2) and UVA + SnCl(2).

Chronic pulmonary toxicity study of indium-tin oxide and indium oxide following intratracheal instillations into the lungs of hamsters.

OBJECTIVES: The aim of this study was to clarify the chronic toxicological effects of indium-tin oxide (ITO) and indium oxide (In(2)O(3)) on laboratory animals. METHODS: Male Syrian golden hamsters were intratracheally administered 3 mg/kg or 6 mg/kg of ITO particles, or 2.7 mg/kg or 5.4 mg/kg of In(2)O(3) particles, containing 2.2 mg/kg or 4.5 mg/kg of indium, twice a week, for 8 wk. Control hamsters were given vehicle of distilled water only. The hamsters were euthanized serially up to 78 wk after the final instillation and the toxicological effects were determined. RESULTS: Body weight gain was significantly suppressed in the ITO 6 mg/kg-treated hamsters compared with the control group, but not in the ITO 3 mg/kg-treated or In(2)O(3)-treated hamsters. Relative lung weights among all the indium-treated groups were significantly increased compared to that in the control group throughout the observation period. The serum indium concentration among all the indium-treated groups gradually increased up to the end of the observation period. Histopathologically, foci of slight to severe pulmonary inflammatory response with diffuse alveolar or bronchiolar cell hyperplasia, expansion of the alveolar spaces and interstitial fibrotic proliferation were present in all the indium-treated hamsters and the severity of these lesions worsened with the passage of time. Lung benign adenomas were only manifest in 3 out of 15 of the ITO 6 mg/kg-treated hamsters. CONCLUSIONS: The present results clearly demonstrate that ITO and In(2)O(3) particles caused chronic pulmonary toxicity when repeated intratracheal instillations were given to hamsters.

In vitro efficacy of experimental tin- and fluoride-containing mouth rinses as anti-erosive agents in enamel.

OBJECTIVES: The aim of this in vitro study was to investigate the efficacy of various experimental tin- and fluoride-containing mouth rinses with stepwise reduced concentrations of the active agents on erosion progression in enamel. METHODS: Human enamel specimens were subjected to a cyclic demineralisation and remineralisation procedure for 10 days with 6 demineralisation periods per day, 5 min each. Erosive demineralisation was performed with 0.05 M citric acid (pH 2.3). Except in the control groups, the specimens were treated for 2 min with experimental mouth rinses after the first and sixth demineralisations. The tin concentrations ranged between 800 and 2800 ppm, and fluoride concentrations of 500 and 250 ppm were used. All preparations were adjusted to pH 4.5. As positive control, a commercially available, tin-containing mouth rinse was used (pH 4.2, 409 ppm Sn(2+), 250 ppm F(-)). Tissue loss was determined profilometrically. RESULTS AND CONCLUSION: As expected, the highest tissue loss was found in the negative control group. All experimental mouth rinses were able to reduce tissue loss significantly (p< or =0.001). The best reduction was achieved by the 2800 ppm Sn(2+), 500 ppm F(-) solution (80%). The lowest reduction was achieved by the 800 ppm Sn(2+), 250 ppm F(-) solution (54%). Amongst the 500 ppm F(-) solutions, in the Sn(2+) concentration range of 2800-800 ppm, only small differences in efficacy were observed, meaning that the tin concentration can probably be reduced without losing efficacy. This factor is particularly important if one regards the possible clinical applicability of such mouth rinses.

Comparison of subareolar injection lymphoscintigraphy with the 1-day and the 2-day protocols for the detection of sentinel lymph nodes in patients with breast cancer.

OBJECTIVE: Lymphoscintigraphy and sentinel node biopsy are used for the detection of axillary lymph node metastasis in breast cancer patients. However, currently there is no standardized technique. For the detection of axillary lymph node metastasis by lymphoscintigraphy and sentinel node biopsy, in patients with breast cancer, we compared the results of subareolar injections administered on the day of surgery (1-day protocol) with injections administered on the day before surgery (2-day protocol). MATERIALS AND METHODS: This study included 412 breast cancer patients who underwent surgery between 2001 and 2004. For the 1-day protocol (1 h before surgery) 0.8 ml of Tc-99m Tin-Colloid (37 MBq) was injected in 203 in the subareolar region on the morning of the surgery. For the 2-day protocol (16 h before surgery) 0.8 ml of Tc-99m Tin-Colloid (185 MBq) was injected in 209 patients on the afternoon before surgery. Lymphoscintigraphy was performed in the supine position and sentinel node identification was performed by hand-held gamma probe during surgery. RESULTS: Among 203 patients with the 1-day protocol, 185 cases (91.1%) were identified by sentinel node lymphoscintigraphy, and 182 cases (89.7%) were identified by gamma probe. Among the 209 patients, in the 2-day protocol, 189 cases (90.4%) had the sentinel node identified by lymphoscintigraphy, and 182 cases (87.1%) by the gamma probe. There was no significant difference in the identification rate of the sentinel node between the 1-day and 2-day protocols by lymphoscintigraphy and the gamma probe (p > 0.05, p > 0.05). CONCLUSIONS: The results of the identification of the sentinel node by subareolar injection according to 1-day or 2-day protocol, in breast cancer patients, showed no significant differences. Because the 2-day protocol allows for an adequate amount of time to perform the lymphoscintigraphy, it is a more useful protocol for the identification of sentinel nodes in patients with breast cancer.

Effect of stannous and fluoride concentration in a mouth rinse on erosive tissue loss in enamel in vitro.

The aim of this in vitro study was to investigate the influence of stannous and fluoride ion concentrations in various experimental solutions on erosion progression in enamel. Human enamel specimens were subjected to a cyclic de- and remineralisation procedure for 10 days, with six demineralisation periods per day, of 5 min each. Erosive demineralisation was performed with 0.05 M citric acid (pH 2.3). Except in the control group, specimens were treated for 2 min with test solutions after the first and the sixth demineralisation. Test solutions were: 1500 mg/L F(-) groups: group 1: 2800 mg/L Sn(2+); group 2: 2100 mg/L Sn(2+); group 3: 1400 mg/L Sn(2+); group 4: 700 mg/L Sn(2+); 1000 mg/L F(-) groups: group 5: 2100 mg/L Sn(2+); group 6: 1400 mg/L Sn(2+). All preparations were adjusted to pH 4.5. Tissue loss was determined profilometrically after the last experimental day. As expected, the greatest tissue loss (microm, mean+/-S.D.) was found in the control group (72.6+/-11.5). All test solutions were able to reduce tissue loss significantly (p

Cytotoxic and genotoxic effects induced by stannous chloride associated to nuclear medicine kits.

At present, more than 75% of routine nuclear medicine diagnostic procedures use technetium-99m (99mTc). The binding between 99mTc and the drug to obtain the radiopharmaceutical needs a reducing agent, with stannous chloride (SnCl2) being one of the most used. There are controversies about the cytotoxic, genotoxic and mutagenic effects of SnCl2 in the literature. Thus, the approaches below were used to better understand the biological effects of this salt and its association in nuclear medicine kits [methylenediphosphonate (MDP) bone scintigraphy and diethylenetriaminepentaacetic acid (DTPA) kidney and brain scintigraphy]: (i) bacterial inactivation experiments; (ii) agarose gel electrophoresis of supercoiled and linear plasmid DNA and (iii) bacterial transformation assay. The Escherichia coli strains used here were AB1157 (wild type) and BW9091 (xthA mutant). Data obtained showed that both MDP and SnCl2 presented a high toxicity, but this was not observed when they were assayed together in the kit, thereby displaying a mutual protect effect. DTPA salt showed a moderate toxicity, and once more, the DTPA kit provided protection, compared to the SnCl2 effect alone. The results suggest a possible complex formation, either MDP-SnCl2 or DTPA-SnCl2, originating an atoxic compound. On the other hand, SnCl2-induced cell inactivation and the decrease in bacterial transformation generated by DTPA found in XthA mutant strain suggest that the lack of this enzyme could be responsible for the effects observed, being necessary to induce DNA damage repair.

CT-guided lymphoscintigraphy in patients with squamous cell carcinoma of the head and neck: a feasibility study.

Accurate knowledge of lymphatic drainage facilitates planning of surgery for patients with squamous cell carcinoma of the head and neck. The aim of this study was to evaluate the feasibility of a new injection technique for lymph node detection in patients with squamous cell carcinoma of the hypopharynx and larynx, in whom simple peritumoural injection is hampered by the tumour localisation. Computed tomography (CT)-guided lymphoscintigraphy was performed in a total of 13 patients with squamous cell carcinoma of the hypopharynx and larynx who could not be injected by simple visual inspection. In a first step, contrast medium-enhanced axial 5-mm-thick CT slices of the neck were obtained. After tumour localisation on these CT images, 1-2 ml contrast medium and, in the event of appropriate distribution, subsequently 50 MBq technetium-99m colloid were injected at one to three peritumoural sites under CT guidance. Peritumoural tracer distribution was controlled by thin-slice CT. Subsequently, planar scintigrams from anterior, right and left lateral views were obtained. In all patients, peritumoural colloid application was feasible, as shown on control CT scans. Post injection, neither severe nor minor complications were noted. The patients complained of only low pain sensations with an average score of 1.8 on a pain scale from 0 to 10. Lymphatic drainage was identified in nine of the 13 patients, with a total of 14 detected lymph nodes. In six patients, ipsilateral sentinel lymph nodes were visualised; bilateral sentinel lymph nodes were identified in one patient and contralateral lymphatic drainage was observed in two patients. CT-guided lymphoscintigraphy is a feasible and minimally invasive diagnostic tool for sentinel lymph node detection in patients with squamous cell carcinoma of the hypopharynx and the larynx. In contrast to endoscopic colloid injection under general anaesthesia, this technique seems to be a well-tolerated method for lymphatic mapping prior to surgical procedures.

Protective effect of SnCl2 on K2Cr2O7-induced nephrotoxicity in rats: the indispensability of HO-1 preinduction and lack of association with some antioxidant enzymes.

We have shown that the ameliorative effect of stannous chloride (SnCl2) pretreatment on potassium dichromate (K2Cr2O7)-induced renal damage 24 h after K2Cr2O7 injection was associated with the induction of heme oxygenase-1 (HO-1). In this work we evaluated: (a) if the protective effect of SnCl2 (given 12 h before K2Cr2O7) is associated with changes in the renal activity of HO-1, superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione reductase (GR), and catalase (CAT) 24 and 48 h after K2Cr2O7 injection, and (b) if HO-1 induction is indispensable before K2Cr2O7 injection. It was found that the protective effect of SnCl2 on renal function was observed both at 24 and 48 h reaching its maximum at 24 h when HO-1 expression was higher. Cu,Zn-SOD, Mn-SOD, and GR activities remained unchanged whereas GPx and CAT activities decreased at 48 h in K2Cr2O7-treated rats. The activity of Cu,Zn-SOD, Mn-SOD, GPx, CAT, and GR was unchanged in the SnCl2-treated rats. To fulfill the objective (b) groups of rats treated with K2Cr2O7 and SnCl2 (given at the same time or 12 h after K2Cr2O7) were studied 24 h after K2Cr2O7-injection. The simultaneous injections of SnCl2 and K2Cr2O7 had no protective effect whereas the injection of SnCl2 12 h after K2Cr2O7 exacerbated renal damage. In conclusion, the protective effect of SnCl2 on K2Cr2O7-induced nephrotoxicity is associated with HO-1 induction and not with other antioxidant enzymes (Cu,Zn-SOD, Mn-SOD, GPx, GR, and CAT) and SnCl2 has a preventive and not a therapeutic effect on renal damage induced by K2Cr2O7.

Lymphoscintigraphic visualization of internal mammary nodes with subtumoral injection of radiocolloid in patients with breast cancer.

OBJECTIVE: To determine whether subtumoral injection of radiocolloid is useful for lymphoscintigraphic visualization of the internal mammary node and in sentinel lymph node (SLN) biopsy of the axilla in breast cancer patients. SUMMARY BACKGROUND DATA: The presence of retromammary lymphatics connecting to the axillary and internal mammary basins has been demonstrated by early anatomic studies. Thus, it is hypothesized that some lymph, especially that from the parenchyma under the tumor, may drain into both the axillary and internal mammary basins. METHODS: Patients (n = 196) with T1-2, N0 breast cancer underwent preoperative lymphoscintigraphy with radiocolloid (technetium 99m tin colloid) injection into various sites of the breast, followed by SLN biopsy using the combined method with blue dye. Patients were divided into four groups: group A (n = 41), peritumoral injection of both radiocolloid and blue dye; group B (n = 70), periareolar radiocolloid and peritumoral blue dye; group C (n = 45), intradermal radiocolloid and periareolar blue dye; and group D (n = 40), subtumoral radiocolloid and intradermal blue dye. A retrospective analysis of 1,297 breast cancer patients who underwent extended radical mastectomy with internal mammary node dissection was also conducted to determine the relationship between vertical tumor location (superficial or deep) and frequency of axillary and internal mammary node metastases. RESULTS: One patient (2%) in group A, 3 (4%) in group B, 0 (0%) in group C, and 15 (38%) in group D exhibited hot spots in the internal mammary region on lymphoscintigraphy (P <.001, group D vs. the other groups). The concordance rate of radiocolloid and blue dye methods in detection of SLNs in the axillary basin was significantly lower in group D than in the other groups. In contrast, the mismatch rate (some SLNs were identified by radiocolloid and other SLNs were identified by blue dye, but no SLN was identified by both in the same patient) was significantly higher in group D than in the other groups. In patients treated with extended radical mastectomy, positivity of axillary and internal mammary metastases was significantly higher in patients (n = 215) with deep tumors than those (n = 368) with superficial tumors. CONCLUSIONS: These results suggest the presence of a retromammary lymphatic pathway from the deep portion of the breast to both axillary and internal mammary basins, which is distinct from the superficial pathway. Therefore, SLN biopsy with a combination of subtumoral and other (peritumoral, dermal, or areolar) injections of radiocolloid will improve both axillary and internal mammary nodal staging.