Epidemiology and genotypic characterisation of dissemination patterns of uropathogenic Escherichia coli in a community.

To characterise the dissemination patterns of uropathogenic Escherichia coli (UPEC) in a community, we conducted a study utilising molecular and fundamental descriptive epidemiology. The subjects, consisted of women having community-acquired acute urinary tract infection (UTI), were enrolled in the study from 2011 to 2012. UPEC isolates were subjected to antibacterial-susceptibility testing, O serogrouping, phylotyping, multilocus-sequence typing with phylogenetic-tree analysis and pulsed-field-gel electrophoresis (PFGE). From the 209 unique positive urinary samples 166 UPEC were isolated, of which 129 were fully susceptible to the tested antibiotics. Of the 53 sequence types (STs), the four most prevalent STs (ST95, ST131, ST73 and ST357) accounted for 60% of all UPEC strains. Antimicrobial resistance was less frequently observed for ST95 and ST73 than for the others. A majority of rare STs and a few common STs constituted the diversity pattern within the population structure, which was composed of the two phylogenetically distinct clades. Eleven genetically closely related groups were determined by PFGE, which accounted for 42 of the 166 UPEC isolates, without overt geo-temporal clustering. Our results indicate that a few major lineages of UPEC, selected by unidentified factors, are disseminated in this community and contribute to a large fraction of acute UTIs.

A rare case of dual origin of the left vertebral artery without convergence.

A case of dual origin of the left vertebral artery was encountered in a dissection course for medical students in 2014. Two vertebral arteries were observed on the left side. One arose from the aortic arch between the origin of the left common carotid artery and the left subclavian artery, entered the transverse foramen of the 4th cervical vertebra, and coursed upward into the transverse foramen. The other arose from the left subclavian artery as expected, divided into two branches anterior to the cervical vertebrae, and entered the transverse foramina of the 6th and 7th cervical vertebrae. Both branches flowed into the anterior spinal artery. Moreover, as seen in other anomalies, 3 arterial fenestrations were observed in the cranial arteries. This case is extremely unique with respect to the following points: the 2 ipsilateral vertebral arteries did not combine to form 1 vertebral artery, the vertebral artery of subclavian artery origin entered the transverse foramen of the 7th cervical vertebra, and 3 fenestrations were observed in the intracranial arteries. This is a very suggestive case for neurosurgeons and radiologists who perform treatments involving the vertebral artery.

The first histological observation of a C1 posterior arch defect.

Deficiencies in the posterior arch of C1 have been well-studied with incidences ranging from 5.65% to 3% and five different classifications. Unfortunately, there is a paucity of information describing the detailed anatomy, muscle attachments, and histology of cases with a C1 posterior arch deficiency. We found a case of an isolated unilateral posterior arch defect in the 83-year-old male cadaver. Histology revealed that the posterior arch defect was filled with collagen fibres and fibrocartilaginous tissue without muscle or bony tissues. This is the first report detailing the histological findings of a posterior arch defect of C1.

Are the nerves supplying the anterior sacroiliac joint nociceptive?

BACKGROUND: Sacroiliac joint (SIJ) pain is often difficult to diagnose. Moreover, while its anatomical characteristics have been well studied, its innervation and the contributions of particular nerves remain controversial, especially in relation to posterior joint innervation. To our knowledge, previous studies have not investigated the presence of nociceptive fibres in the nerves innervating the anterior SIJ. MATERIALS AND METHODS: Eight adult cadaveric sides underwent dissection of the anterior SIJ. Adjacent anterior rami were examined for branches to the anterior SIJ. Any branches contributing to the anterior SIJ were measured and then resected. These samples were fixed in formalin and substance P was identified immunohistologically. RESULTS: On all sides, 1-2 small branches (mean diameter of 0.33 mm) arose from the posterior aspect of the L4 anterior ramus (12.5%), the L5 anterior ramus (62.5%), or simultaneously from both the L4 and L5 anterior rami (25%). These branches had a mean length of 13.5 mm. All histological samples contained nerve tissue. All samples of nerve fibres traveling to the anterior SIJ were positive for diffuse substance P reactivity. There were no histological differences between sides or sex. Each of the branches identified as travelling to the SIJ exhibited similar positivity for substance P. CONCLUSIONS: This cadaveric study demonstrates that the anterior SIJ nerve fibres carry pain fibres. This new knowledge has application to patients with SIJ syndrome and to its various treatments including interventional approaches to SIJ pain.

Long-term effects of hepatocyte growth factor gene therapy in rat myocardial infarct model.

We investigated the long-term effects of human hepatocyte growth factor (HGF) gene therapy in a rat myocardial infarct model. Treatment adenovirus coexpressing the HGF therapeutic gene and the human sodium/iodide symporter (NIS) reporter gene or control adenovirus expressing the NIS gene alone were injected directly into the infarct border zone immediately after permanent coronary ligation in rats (n=6 each). A uniform disease state was confirmed in the acute phase in terms of impaired left ventricular (LV) function by cine magnetic resonance imaging (MRI), large infarct extent by (99m)Tc-tetrofosmin single-photon emission computed tomography (SPECT) and successful gene transfer and expression by (99m)TcO(4)(-) SPECT. After a 10-week follow-up, repeated cine MRI demonstrated no significant difference in the LV ejection fraction between the time points or groups, but a significantly increased end-diastolic volume from the acute to the chronic phase without a significant difference between the groups. Capillary density was significantly higher in the treatment group, whereas arteriole density remained unchanged. Two-photon excitation fluorescence microscopy revealed extremely thin capillaries (2-5 µm), and their irregular networks increased in the infarct border zone of the treated myocardium. Our results indicated that single HGF gene therapy alone induced an immature and irregular microvasculature.

[Application of the lower partial sternotomy approach to patients who may need tracheostomy in the early period after cardiac surgery].

Recent good results of cardiovascular surgery have led to expansion of its indication to elderly patients and patients with serious complications. Such patients may have serious respiratory complications after cardiac surgery and need to undergo tracheostomy relatively early in the postoperative period. Although the full sternotomy approach is the standard in almost all cardiac surgeries, superficial and deep sternal infections are rather common after early tracheostomy in full sternotomy patients. The lower partial sternotomy approach is a safer and more useful procedure in patients who will need tracheostomy in the early period after cardiac surgery. We report on 2 patients who were successfully tracheostomized within a week after cardiac surgery, with a review of the literature.

Noninvasive assessment of regulable transferred-p53 gene expression and evaluation of therapeutic response with FDG-PET in tumor model.

The use of tumor-suppressor gene p53 as an anticancer therapeutic has been vigorously investigated. However, progress has met with limited success to date. Some major drawbacks are the difficulty in achieving controllable and efficient gene transfer as well as in analyzing the transferred gene expression in real time and the treatment response in a timely manner. Thus, development of novel gene transfer vector with a regulative gene expression system coupled with the reporter gene, by which transgene can be monitored simultaneously, is critical. Moreover, noninvasive imaging-based assessment of the therapeutic response to exogenous wild-type p53 gene transfer is crucial for refining treatment protocols. In this study, as a simple preclinical model, we constructed a doxycycline-regulated bidirectional vector harboring a reporter gene encoding red fluorescence protein and p53. Then, we determined the controllable and simultaneously coordinated expression of both proteins and the p53-mediated anticancer effects in vitro and in vivo. Next, we observed that cells or tumors with induced p53 overexpression exhibited decreased uptake of [(14)C]FDG in cellular assay and [(18)F]FDG in positron emission tomography (PET) imaging. Thus, by coupling with bidirectional vector, controllable p53 transfer was achieved and the capability of fluoro-2-deoxy-D-glucose (FDG)-PET to assess the therapeutic response to p53 gene therapy was evidently confirmed, which may have an impact on the improvement of p53 gene therapy.

Visualization of in vivo electroporation-mediated transgene expression in experimental tumors by optical and magnetic resonance imaging.

In vivo electroporation (EP) is an efficient method for effective gene transfer and is highly expected for application in anticancer gene therapy. Non-invasive monitoring of gene transfer/expression is critical for optimal gene therapy. Here we report in vivo optical and high-field magnetic resonance imaging (MRI) of EP-mediated transgene expression in a tumor model. Initially, we observed spatio-temporal change in in vivo EP-mediated transgene expression by optical imaging using red fluorescence protein (RFP) as a reporter gene. Next, we constructed a dual-reporter plasmid carrying a gene-encoding MRI reporter ferritin heavy chain and RFP gene to visualize the intratumoral transgene expression by dual modality. Cells transfected with this plasmid showed lower signal intensity on in vitro T(2)-weighted cellular MRI and quantitatively increased the transverse relaxation rate (1/T(2)) compared with control cells. After conducting in vivo EP in an experimental tumor, the plasmid-injected region showed both fluorescent emissions in optical imaging and detectably lowered signal on T(2)-weighted MRI. The correlative immunohistological findings confirmed that both the reporter transgenes were co-expressed in this region. Thus, our strategy provides a platform for evaluating EP-mediated cancer gene therapy easily and safely without administering contrast agent or substrate.

MRI of cerebral micro-vascular flow patterns: A multi-direction diffusion-weighted ASL approach.

The study and clinical assessment of brain disease is currently hindered by a lack of non-invasive methods for the detailed and accurate evaluation of cerebral vascular pathology. Angiography can detect aberrant flow in larger feeding arteries/arterioles but cannot resolve the micro-vascular network. Small vessels are a key site of vascular pathology that can lead to haemorrhage and infarction, which may in turn trigger or exacerbate neurodegenerative processes. In this study, we describe a method to investigate microvascular flow anisotropy using a hybrid arterial spin labelling and multi-direction diffusion-weighted MRI sequence. We present evidence that the technique is sensitive to the mean/predominant direction of microvascular flow in localised regions of the rat cortex. The data provide proof of principle for a novel and non-invasive imaging tool to investigate cerebral micro-vascular flow patterns in healthy and disease states.

Avidin targeting of intraperitoneal tumor xenografts.

BACKGROUND: Lectins (proteins that bind specific sugar molecules on glycoproteins and glycolipids) are expressed at various levels on the surface of tumor cells. Conjugation of cytotoxic agents to glycoproteins recognized by lectins could be useful in the treatment of tumors. Avidin (a highly glycosylated, positively charged protein found in egg white) contains terminal N-acetylglucosamine and mannose residues that bind to some lectins. In this study, we tested the ability of avidin, labeled through conjugation to radioactive biotin (a B vitamin), to target intraperitoneal tumors. METHODS: Biotin was radioactively labeled with 111In. Four tumor models (one ovarian, one lung, and two colon) were established in nude mice by intraperitoneal injection of cultured cancer cells. The following two approaches were used in the intraperitoneal administration of avidin: 1) radioactive biotin-avidin conjugates were injected and 2) avidin was injected 1-24 hours before the injection of radioactive biotin (avidin pretargeting; avidin-biotin conjugates formed in vivo). The distribution of injected radioactivity in the tissues of treated animals was assessed. RESULTS: Radiolabeled avidin localized highly and rapidly in the tumors. More than 50% of the administered dose of avidin-biotin conjugate accumulated per gram of tumor tissue 2 hours after injection; high tumor uptake of radioactivity was observed up to 24 hours after conjugate injection. In contrast, accumulation of radioactivity in normal tissues was low, yielding high tumor to nontumor ratios. With avidin pretargeting, accumulation of radioactivity in the liver, kidney, and spleen was reduced to a greater extent than that in the tumor, and tumor to nontumor ratios were increased. CONCLUSIONS: Avidin may be a promising vehicle for the delivery of radioisotopes, drugs, toxins, or therapeutic genes to intraperitoneal tumors.

Pharmacokinetics of internally labeled monoclonal antibodies as a gold standard: comparison of biodistribution of 75Se-, 111In-, and 125I-labeled monoclonal antibodies in osteogenic sarcoma xenografts in nude mice.

In order to know the true biodistribution of anti-tumor monoclonal antibodies, three monoclonal antibodies (OST6, OST7, and OST15) against human osteosarcoma and control antibody were internally labeled with 75Se by incubating [75Se]methionine and hybridoma cells. 75Se-labeled monoclonal antibodies were evaluated both in vitro and in vivo using the human osteogenic sarcoma cell line KT005, and the results were compared with those of 125I- and 111In-labeled antibodies. 75Se-, 125I- and 111In-labeled monoclonal antibodies had identical binding activities to KT005 cells, and the immunoreactivity was in the decreasing order of OST6, OST7, and OST15. On the contrary, in vivo tumor uptake (% injected dose/g) of 75Se- and 125I-labeled antibodies assessed using nude mice bearing human osteosarcoma KT005 was in the order of OST7, OST6, and OST15. In the case of 111In, the order was OST6, OST7, and OST15. High liver uptake was similarly seen with 75Se- and 111In-labeled antibodies, whereas 125I-labeled antibodies showed the lowest tumor and liver uptake. These data indicate that tumor targeting of antibody conjugates are not always predictable from cell binding studies due to the difference of blood clearance of labeled antibodies. Furthermore, biodistribution of both 111In- and 125I-labeled antibodies are not identical with internally labeled antibody. Admitting that internally labeled antibody is a "gold standard" of biodistribution of monoclonal antibody, high liver uptake of 111In-radiolabeled antibodies may be inherent to antibodies. Little, if any, increase in tumor-to-normal tissue ratios of antibody conjugates will be expected compared to those of 111In-labeled antibodies if stably coupled conjugates are administered i.v.

Streptavidin distribution in metastatic tumors pretargeted with a biotinylated monoclonal antibody: theoretical and experimental pharmacokinetics.

We have developed a pharmacokinetic model for the analysis of a protocol that involves injection of a biotinylated monoclonal antibody followed at a later time by radiolabeled streptavidin. Three distinct physiological spaces are described: an avascular tumor nodule, the normal tissue surrounding the tumor, and the plasma. The model incorporates processes such as plasma kinetics, transcapillary transport, interstitial diffusion, binding reactions, and lymphatic clearances. We have modeled cases in which antigen turnover does not occur, in which antigen turnover does occur (24-h time constant), and in which circulating antibody is cleared from the plasma immediately prior to injection of streptavidin. We have calculated the spatial and temporal distributions of a tumor-specific antibody and of streptavidin in the tumor nodule using parameter values that simulate conditions of recent experiments on metastatic nodules in the guinea pig lung. The theoretical distribution of streptavidin in the tumor nodule shows an initial localization at the periphery that progresses to a fairly uniform distribution throughout the nodule, a temporal sequence that is very similar to experimental observation. This finding indicates that, in a tumor pretargeted with biotinylated antibody, streptavidin can encounter significant retardation in its penetration as a consequence of the high affinity interaction between these two species. Tumor:blood and tumor:lung ratios were calculated and compared to experimental results. In addition, the calculated tumor:blood ratios, tumor:lung ratios, and relative exposures were compared to values obtained from a model of one-step antibody delivery. The two-step protocol yielded an approximately 2- to 3-fold enhancement in these pharmacokinetic indices compared with the one-step method.

Effect of tumor mass and antigenic nature on the biodistribution of labeled monoclonal antibodies in mice.

The effect of tumor mass and antigenic nature on the biodistribution of 111In- and 125I-labeled monoclonal antibodies (MoAbs) was studied using F(ab')2 fragments of three representative anti-tumor MoAbs and SW1116 human colorectal carcinoma grown in nude mice. The 19-9, F33-104 anti-CEA, and 17-1A MoAbs showed specific binding to SW1116 cells. The former two MoAbs recognize circulating CA 19-9 with molecular weights of more than 5,000,000 and CEA of Mr 170,000-180,000, respectively, whereas 17-1A reacts with a nonshedding antigen. Both percentage injected dose per gram tumor and tumor-to-blood ratios were inversely proportional to the tumor mass in nude mice administered 111In- and 125I-labeled 19-9, but liver uptake increased as tumor size increased. Analysis of serum samples and tumor homogenates demonstrated the presence of a high-molecular-weight species, probably due to the antibody binding to CA 19-9. In the case of 111In-labeled anti-CEA MoAb, tumor uptake also decreased and liver uptake increased with tumor size, but this effect was less obvious than that of 19-9. In contrast, tumor and liver uptake of 125I-labeled anti-CEA MoAb, 111In- and 125I-labeled 17-1A and control antibodies were independent of tumor mass. The absolute tumor uptake and tumor-to-blood ratios of all 125I-labeled antibodies were lower than those of the 111In-labeled ones. And the effect of tumor mass was also weaker with 125I-labeled antibodies, probably due to in vivo dehalogenation. These results indicate that the effect of tumor size on the incorporation of labeled MoAb into tumors is dependent on the antigenic nature to be targeted and/or radionuclides used for labeling and that high concentrations of circulating high molecular weight antigens may limit in vivo use of MoAb conjugates.

67Ga-labeled antibodies for immunoscintigraphy and evaluation of tumor targeting of drug-antibody conjugates in mice.

To assess the in vivo behavior of cytotoxic agents linked to antibodies, deferoxamine, known to form stable chelates with 67Ga, was conjugated with monoclonal antibodies using three different methods. One method used a homocoupling reagent, glutaraldehyde, whereas two other methods used heterocoupling reagents, N-succinimidyl-3-(2-pyridyldithio)propionate and succinimidyl-6-maleimidohexanoate, linking deferoxamine to antibodies through alkylamine, disulfide, and thioether bonds, respectively. Antibodies were efficiently labeled with 67Ga through chelation with deferoxamine without losing antigen-binding capability. 67Ga-labeled antibodies clearly visualized transplanted tumors in nude mice. However, the biodistribution of radioactivity was markedly different with the coupling methods used for the conjugation of deferoxamine and antibodies. High nonspecific uptake in the liver and spleen was observed with 67Ga-labeled antibodies prepared by the glutaraldehyde method. 67Ga-labeled antibodies linked by thioether bonds demonstrated in vivo stability and the highest tumor:liver ratio, whereas 67Ga-labeled antibodies conjugated with disulfide bonds were rapidly cleared from the circulation. These results indicate that antibody conjugates linked by thioether bonds are a better choice for drug targeting and that 67Ga-labeled antitumor monoclonal antibodies are useful not only for the immunoscintigraphy but also for the quantitative assessment and visualization of the biodistribution of drug-antibody conjugates.

Scintigraphic detection of overexpressed c-erbB-2 protooncogene products by a class-switched murine anti-c-erbB-2 protein monoclonal antibody.

Class-switched monoclonal antibody SV2-61r recognized the extracellular domain of c-erbB-2 protooncogene products separate from the epidermal growth factor receptor. We studied the potential of SV2-61r for evaluating the amplification of c-erbB-2 protooncogene on cancer cells, which has been reported to have prognostic value in adenocarcinoma patients. Radiolabeled SV2-61r specifically bound to various adenocarcinoma cells in addition to c-erbB-2-transfected NIH-3T3 cells (A4) with the affinity constant of 4.4 x 10(8) M-1. SV2-61r injected i.v. localized well to A4 cells xenografted in nude mice. Tumor uptake and localization index of radioiodinated SV2-61r were lower than those of 111In-labeled SV2-61r, probably due to the internalization and dehalogenation of formed antibody-antigen complexes. Biodistribution and specificity of targeting were assessed by comparison among three cells, A4, lung cancer SBC-3 (c-erbB-2 weakly positive) and B-lymphoblastoid Manca cells (c-erbB-2 negative). Tumor:blood ratios, obtained 48 h after injection, were 5.63, 1.45, and 0.68, respectively, indicating the potential of 111In-labeled SV2-61r for evaluating the amplification of c-erbB-2 protooncogene on cancer cells. Because of its close relationship with carcinogenesis and the uniform expression, c-erbB-2 protooncogene products seem to be the optimal target of imaging and therapy of adenocarcinoma patients.

Dynamic micro-magnetic resonance imaging of liver micrometastasis in mice with a novel liver macromolecular magnetic resonance contrast agent DAB-Am64-(1B4M-Gd)(64).

DAB-Am64-(1B4M-Gd)(64) is a newly synthesized macromolecular liver magnetic resonance imaging (MRI) contrast agent with a polypropylenimine diaminobutane (DAB) dendrimer conjugated with a bifunctional diethylenetriaminepentaacetic acid (DTPA) derivative for complexing Gd(III) atoms. The characteristics of DAB-Am64-(1B4M-Gd)(64), which quickly accumulated in the liver, have been reported recently. In the present study, the dynamic micro-MRI with DAB-Am64-(1B4M-Gd)(64) was obtained in the mouse liver metastasis model using colon carcinoma cells to evaluate the ability to visualize the micrometastatic tumors compared with that using Gd-DTPA. The dynamic micro-MRI with DAB-Am64-(1B4M-Gd)(64) was able to homogeneously enhance the normal liver parenchyma and visualize micrometastatic tumors of 0.3-mm diameter in the liver of the mice with better contrast than that with Gd-DTPA. In conclusion, DAB-Am64-(1B4M-Gd)(64) is a new liver MRI contrast agent potentially useful for diagnosis of micrometastasis in the liver.

Two-step targeting of experimental lung metastases with biotinylated antibody and radiolabeled streptavidin.

Two-step monoclonal antibody tumor targeting using an avidin-biotin system has unique characteristics because of the high-affinity binding (10(15) M-1) and the lower molecular weight ligands (avidin, streptavidin, or biotin) used as carriers of radioisotopes, toxins, or drugs. The distribution of radiolabeled streptavidin in a two-step targeting strategy was investigated in lung metastases of line 10 carcinoma in guinea pigs. The microdistribution of administered D3 monoclonal antibody and 125I-labeled streptavidin in metastatic nodules was examined by immunohistochemistry and autoradiography, and the uptake was quantitated. With monoclonal antibody pretargeting, streptavidin was found mainly at the periphery of metastatic nodules 1.5 h after injection; it had penetrated deeper at 4 h and was approaching homogeneity in many of the tumor nodules at 24 h. These results indicate that streptavidin can penetrate into metastatic nodules more rapidly than can the antibody. The concentration of streptavidin in metastatic nodules 4 h after injection was 5.6 times higher for the pretargeted group than for the nonpretargeted group, and the pretargeting index was 4.7. Although the absolute uptake of streptavidin had decreased between 4 and 24 h, the metastasis:blood ratio had increased from 1.2 to 2.4. When compared with the animals injected with 125I-labeled D3 antibody alone, the pretargeted group achieved higher tumor:blood and tumor:lung ratios and a higher localization index at early times after injection of the radiolabeled species.

Molecular epidemiologic analysis of a Pneumocystis pneumonia outbreak among renal transplant patients.

Between 18 November and 3 December 2011, five renal transplant patients at the Department of Nephrology, Toho University Omori Medical Centre, Tokyo, were diagnosed with Pneumocystis pneumonia (PCP). We used molecular epidemiologic methods to determine whether the patients were infected with the same strain of Pneumocystis jirovecii. DNA extracted from the residual bronchoalveolar lavage fluid from the five outbreak cases and from another 20 cases of PCP between 2007 and 2014 were used for multilocus sequence typing to compare the genetic similarity of the P. jirovecii. DNA base sequencing by the Sanger method showed some regions where two bases overlapped and could not be defined. A next-generation sequencer was used to analyse the types and ratios of these overlapping bases. DNA base sequences of P. jirovecii in the bronchoalveolar lavage fluid from four of the five PCP patients in the 2011 outbreak and from another two renal transplant patients who developed PCP in 2013 were highly homologous. The Sanger method revealed 14 genomic regions where two differing DNA bases overlapped and could not be identified. Analyses of the overlapping bases by a next-generation sequencer revealed that the differing types of base were present in almost identical ratios. There is a strong possibility that the PCP outbreak at the Toho University Omori Medical Centre was caused by the same strain of P. jirovecii. Two different types of base present in some regions may be due to P. jirovecii's being a diploid species.

Quantitative rest technetium-99m tetrofosmin imaging in predicting functional recovery after revascularization: comparison with rest-redistribution thallium-201.

OBJECTIVES: This study was undertaken to 1) compare the regional myocardial tracer distributions between rest technetium (Tc)-99m tetrofosmin and rest-redistribution thallium (Tl)-201 images in patients with coronary artery disease and left ventricular dysfunction; and 2) assess the comparative values of these agents for predicting functional recovery after revascularization. BACKGROUND: Tc-99m tetrofosmin is a new myocardial perfusion imaging agent, but its role for detecting viable myocardium is still unclear. METHODS: Thirty-six patients with coronary artery disease and left ventricular dysfunction underwent rest Tc-99m tetrofosmin, rest-redistribution Tl-201 and gated blood pool scintigraphy. In 21 patients with successful revascularization confirmed by follow-up angiography, gated blood pool scintigraphy was repeated after revascularization. Optimal threshold cutoffs to separate reversible from irreversible dysfunction were determined by receive operating characteristic analysis. RESULTS: Regional Tc-99m tetrofosimin activity highly correlated with redistribution Tl-201 activity (r = 0.93). The diagnostic performance for predicting functional recovery, as measured by the area under the receiver operating characteristic curves, measured 0.66 +/- 0.07 (mean +/- SD) for Tc-99m tetrofosmin and 0.67 +/- 0.07 for Tl-201 (p = 0.60, 96.7% power to detect difference in area of 0.10). The optimal threshold cutoffs for viability were considered to be 50% of peak activity for Tc-99m tetrofosmin and 55% of peak activity for Tl-201. The positive and negative predictive values for reversible dysfunction were, respectively, 69% and 82% for Tc-99m tetrofosmin and 69% (p = 0.99 vs. Tc-99m tetrofosmin) and 71% (p = 0.66 vs. Tc-99m tetrofosmin) by Tl-201. CONCLUSIONS: The diagnostic performance of quantitative rest Tc-99m tetrofosmin imaging in predicting functional recovery after revascularization is comparable to that of rest-redistribution Tl-201.

Residual formaldehyde on plastic materials and medical equipment following low-temperature steam and formaldehyde sterilization.

We measured the amount of residual formaldehyde on 16 plastic materials and five medical devices following low-temperature steam and formaldehyde (LTSF) sterilization, based on the European Standard EN14180. The amounts of formaldehyde residue on the plastic materials were compared with that on a filter paper of similar dimensions. The amount of residual formaldehyde on polyamide 6, polyurethane, natural rubber and polyacetal was higher (21.9, 15.2, 3.0 and 2.1 times, respectively) than that on the filter paper. The amount of formaldehyde recovered from a breathing circuit, anaesthesia circuit, oxygen tubing, airway tube and tweezers was 260, 240, 594, 56 and 0 microg, respectively, following LTSF sterilization. Our results emphasize the need to verify the main material composing the medical equipment before LTSF sterilization, as the amount of formaldehyde retrieved following sterilization varies according to the material used for construction.