Utilización de hematíes marcados con 99Mtc y desnaturalizados por calor en el diagnóstico gammagráfico de un caso infrecuente de esplenosis intratorácica / Use of heat-denatured 99mTC -labeled red blood cells in the scintigraphic diagnosis of an infrequent case of intrathoracic splenosis

La esplenosis intratorácica es poco frecuente y se asocia con historia previa de ruptura del bazo y del diafragma causado por un traumatismo. Suele ser asintomática, presentándose como un hallazgo accidental en las imágenes radiográficas o de tomografía computarizada. El diagnóstico definitivo puede realizarse mediante estudios gammagráficos asociados con estudios funcionales de captación de partículas o células. Por su sensibilidad y especificidad, la gammagrafía con hematíes marcados con 99mTc y desnaturalizados por calor es la técnica de referencia que permite confirmar el diagnóstico de esplenosis y diferenciarla de otros procesos que requieren resección quirúrgica. Se describe el caso de un varón de 52 años atendido por dolor de tipo pleurítico en hemitórax izquierdo. Las imágenes mostraron derrame pleural izquierdo e infarto pulmonar sin signos de tromboembolismo. Se evidenciaron múltiples focos sugestivos de esplenosis, que fue confirmada mediante gammagrafía esplénica con hematíes marcados con 99mTc y desnaturalizados por calor

Intrathoracic splenosis is extremely rare and is associated with previous history of rupture of the spleen and diaphragm caused by trauma. It is usually asymptomatic, presenting as an accidental finding in the X-ray images or computed tomography. The definitive diagnosis can be made by scintigraphic studies associated with functional studies of particle or cell uptake. Due to its sensitivity and specificity, gammagraphy with heat-denatured 99mTc-labeled red blood cells is the reference technique for confirming the diagnosis of splenosis and differentiating it from other processes that require surgical resection. We describe the case of a 52-year-old man treated for pleuritic pain in the left hemithorax. The images showed left pleural effusion and pulmonary infarction without signs of thromboembolism. There were multiple foci suggestive of splenosis, which was confirmed by splenic scintigraphy with heat-denatured 99mTc-labeled red blood cells

Synthesis of 5-hydroxymethylfurural from carbohydrates using large-pore mesoporous tin phosphate.

A large-pore mesoporous tin phosphate (LPSnP-1) material has been synthesized hydrothermally by using Pluronic P123 as the structure-directing agent. The material is composed of aggregated nanoparticles of 10-15 nm in diameter and has a BET surface area of 216 m(2) g(-1) with an average pore diameter of 10.4 nm. This pore diameter is twice as large as that of mesoporous tin phosphate materials synthesized through the surfactant-templating pathways reported previously. LPSnP-1 shows excellent catalytic activity for the conversion of fructose, glucose, sucrose, cellobiose, and cellulose to 5-hydroxymethylfurfural (HMF) in a water/methyl isobutyl ketone biphasic solvent to give maximum yields of HMF of 77, 50, 51, 39, and 32 mol %, respectively, under microwave-assisted heating at 423 K. Under comparable reaction conditions, LPSnP-1 gives 12 % more HMF yield than a small-pore mesoporous tin phosphate catalyst that has an identical framework composition. This confirms the beneficial role of large mesopores and nanoscale particle morphology in catalytic reactions that involve bulky natural carbohydrate molecules.

Investigations of Ce3+ co-doped SbPO4:Tb3+ nano-ribbons and nanoparticles by vibrational and photoluminescence spectroscopy.

Nano-ribbons and very small nanoparticles (size 2-5 nm) of SbPO4 doped with lanthanide ions (Ce3+ and Tb3+) are prepared at a relatively low temperature of 120 degrees C based on a solution method. Detailed vibrational and luminescence studies on these samples establish that these lanthanide ions are incorporated at Sb3+ site of the SbPO4 lattice. The excitation spectrum corresponding to the Tb3+ emission and the excited state lifetime of the 5D4 level of Tb3+ ions in the sample confirm the energy transfer from Ce3+ to Tb3+ ions in the SbPO4 host. The extent of energy transfer from Ce3+ to Tb3+ in these samples is found to be around 60%. Dispersion of these nanomaterials in silica matrix effectively shields the lanthanide ions at the surface of the nano-ribbons/nanoparticles from the stabilizing ligands resulting in the reduction in the vibronic quenching of the excited state. Our results show significant reduction in the surface contribution in the decay curve corresponding to the 5D4 level of the Tb3+ ions after incorporating the nano-ribbons/nanoparticles in silica. These nanomaterials incorporated in silica matrix can have potential applications in bio-assays and bio-imaging.

Development of a new semi-quantitative non-invasive method for evaluating ventricular stroke work.

BACKGROUND AND AIM: Ventricular stroke work (SW) is one of the best indices to evaluate ventricular function, however, the SW monitoring mainly depends on the invasive method with the artery catheter. In this paper, our aim is to develop a new semi-quantitative non-invasive method for evaluating ventricular SW. METHODS: The multiple gated cardiac blood pool imaging was done in 25 patients with coronary artery disease and 12 normal controls. A new parameter, the relative stroke work (RSW) of left ventricle, was calculated using an equation derived from the principle of hydrodynamics. The left ventricular SW was analyzed by stroke volume (SV) and mean arterial pressure. Ejected fraction (EF), peak ejected rate (PER) and peak filling rate (PFR) were gotten with the routine software in imaging device. RESULTS: The left ventricular RSW was linearly correlated with the SW. The RSW was related to the SV, EF, PER and PFR of the left ventricle. The RSW had regressive relation with SV and PER. The RSW in patients, same as SW, SV, EF, PFR and PER, was noticeably lower than that in normal controls, P<0.01. CONCLUSION: The RSW is a potential and valuable clinical index for evaluation of the ventricular function.

Insoluble zinc, cupric and tin pyrophosphates inhibit the formation of volatile sulphur compounds.

Oral malodour is mainly a result of the production of volatile sulphur compounds (VSC). The present study was concerned with investigating the anti-VSC effect of insoluble pyrophosphates (PP) of zinc, copper(II) and tin(II). The hypothesis to be tested was that the sulphide anions produced when VSC are solubilized in water have a higher affinity for the respective metal ions than the PP anion. The anti-VSC effects of insoluble PP were compared with the corresponding soluble metal salts using three in vitro methods: saliva putrefaction; dialysis of a suspension of PP and saliva against water; and analysis of water containing hydrogen sulphide and methyl mercaptan gases, and gases in the headspace. The levels of VSC were analysed by gas chromatography in the first and third methods, and released metal ions were analysed by atomic absorption spectroscopy in the second. The results showed that: the insoluble metal PP inhibited VSC formation in saliva by 99-100%; under dialysis, only minute amounts of metal ions are released from the combination of PP and saliva; and the PP lost their metal cations in water containing dissolved gases and inhibited VSC formation. Hence, the results support the experimental hypothesis. Sulphide ions are obviously very strong ligands for these metal ions.

Poor labeling of Tc-99m red blood cells in vivo in a radionuclide intestinal bleeding study of a patient who had recently undergone frequent blood transfusions.

The authors report poor labeling of Tc-99m red blood cells (RBCs) in vivo in a radionuclide intestinal bleeding study of a patient who had recently undergone frequent blood transfusions. The existence of RBC antibodies, as a result of the recent blood transfusions in this patient, was one of the causes of the poor labeling. In radionuclide bleeding studies with patients with recent blood transfusion, Tc-99m HSA-D must be chosen instead of Tc-99m RBCs in vivo.

Feasibility and accuracy of left ventricular volumes and ejection fraction determination by fundamental, tissue harmonic, and intravenous contrast imaging in difficult-to-image patients.

The need to enhance the echocardiographic determination of left ventricular ejection fraction is greatest in patients with suboptimal images. Intravenous contrast (CON) and tissue harmonic imaging (THI) are 2 important methods for enhancing endocardial border definition. However, the comparative feasibility and accuracy of THI and contrast-enhanced power harmonic imaging in difficult-to-image patients have not been examined. We assessed the comparative accuracy of THI and CON in determining EF and ventricular volumes in patients with suboptimal fundamental images. We demonstrated that CON is feasible and exhibits a greater correlation with ejection fraction and ventricular volumes determined by radionuclide angiography (standard of comparison) than THI in this difficult-to-image population, with no reported side effects. For both ejection fraction and ventricular volumes, the observer variability was least for CON, intermediate with THI, and greatest for fundamental imaging.

[Radiochemical purity and stability of Tc-99m-pyrophosphate]. / Radiohemijska cistoca i stabilnost Tc-99m-pirofosfata.

INTRODUCTION: In vitro stability of 99mTc-radiopharmaceuticals is an important parameter of quality. In the paper the shelf-life of the bone-seeking radiopharmaceutical 99mTc(Sn)-pyrophosphate was examined under different experimental conditions. MATERIAL AND METHODS: The solution of pyrophosphate was prepared and dispensed into 2-ml fractions which were kept at-20 degrees C. In different time intervals the samples were thawed and labeled. The in vitro stability of labeled preparation was examined on the unprotected and the samples protected by nitrogen purge or by addition of solutions of ascorbic or genetisic acid of known concentrations. The content of 99mTc-pertechnetate was determined by paper chromatography. RESULTS AND DISCUSSION: In comparison with unprotected, samples protected by nitrogen purge exhibit better, but not satisfactory stability. Best results are obtained by using chemical stabilizers. The presence of 50-60 micrograms/ml of ascorbic acid keeps the content of 99mTc-pertechnetate below 5% during six hours even in solutions of high initial radioactive concentrations (up to about 814 MBq/ml). With this concentration of ascorbic acid, good results are obtained also by labeling inactive solutions kept at low temperatures during seven days. Genetisic acid is also efficient but its concentration should be about ten times higher. CONCLUSION: The in vitro stability of 99mTc(Sn)-pyrophosphate depends on the initial radioactive concentration of 99mTc and time after labeling. Best results were obtained when the preparation contained ascorbic acid as a chemical stabilizer. Its concentration in the range of 50-60 micrograms/ml is sufficient to keep the content of 99mTc-pertechnetate below 5% during six hours, both in freshly prepared samples and those kept at low temperatures for seven days.

Ultratag RBC kit for combined cardiac first-pass and multigated acquisition studies.

UNLABELLED: The authors developed a procedure to use the in vitro Ultratag (Mallinckrodt, St. Louis, MO) red blood cell (RBC) labeling kit for both first-pass (FP) and multigated acquisition (MUGA) studies with a high specific activity in a reduced volume (50 mCi/0.5 ml) and a high labeling efficiency that can be used with a single-crystal camera to yield a quality study. METHODS: A packed red blood cell (PRBC) bolus was created by two methods: (a) reducing the volume of the components of the Ultratag kit and (b) centrifuging the final dose volume. The labeling efficiency of each bolus was evaluated, each PRBC bolus was visually inspected for clots and percent hemolysis was assessed using a hemocytometer at 30 min, 1 hr and 2 hr postcentrifugation. RESULTS: Use of the first method, the 50% kit, provided the best results. However, the resulting volume from this kit only approached 1 ml, which is not clinically adequate for a first-pass study. In the second method, the total volume was centrifuged to form a PRBC bolus, which appeared to be stable in the syringe for at least 2 hr. A combined FP/MUGA study from a centrifuged 50% reduced kit was performed in one normal subject as a preliminary assessment of the clinical utility of this procedure. The image quality of the scan is diagnostically adequate. CONCLUSION: By using the in vitro Ultratag kit, a compact PRBC bolus was created that was stable in the syringe and could be reinjected safely into the patient for combined cardiac FP/MUGA studies.

Studies on stannous fluoride toothpaste and gel (1). Antimicrobial properties and staining potential in vitro.

Stannous fluoride (SF) in a toothpaste vehicle has the potential to provide anticaries and plaque inhibitory benefits through the fluoride and antimicrobial stannous moieties respectively. Dental staining, however, can occur by precipitation of dietary chromogens onto the tooth surface by stannous ions. These studies in vitro compare the antimicrobial profile and propensity to cause tea staining of a number of stannous fluoride formulations. The formulations used were 2 SF toothpaste products (SF1, SF2), 2 experimental SF plus stannous pyrophosphate toothpastes (SFSP1, SFSP2), a SF gel (G) and a NaF toothpaste (C). Maximum inhibitory dilution values against a range of oral bacteria were determined by agar dilution. Tea staining was measured spectrophotometrically on saliva coated clear acrylic blocks exposed to slurries of the paste or gel. All formulations showed antimicrobial activity with the order of greatest activity downwards being C, SF2, SF1, SFSP1, SFSP2 and G. Tea staining at 10 exposures was in the following descending order of optical density SFSP1, SFSP2, G. C, SF1, SF2, water control. The antimicrobial profile of G was similar to that of SF, whereas that of the other formulations were varied but similar to a detergent profile. The difference in staining suggested considerable variation in availability of stannous ions in the formulations. However, the propensity for stannous ions to stain must be balanced against the stain removal propensity of the contained detergents in the toothpaste formulations. In conclusion, the variation in antimicrobial activity and more particularly staining activity of the formulations suggest the products will vary in activity in vivo.

Studies on stannous fluoride toothpaste and gel (2). Effects on salivary bacterial counts and plaque regrowth in vivo.

There has been a resurgence of interest in stannous fluoride (SF) products in particular to provide oral hygiene and gingival health benefits. The aim of this study was to assess the persistence of antimicrobial action of a number of SF formulations in the mouth and relate these to plaque inhibitory activity. The formulations were 2 SF toothpastes (SF1, SF2), 2 SF plus stannous pyrophosphate toothpastes (SFSP1, SFSP2), a SF gel (G), a NaF toothpaste (C) and saline (S) as control. Both studies involve 2 different groups of 21 healthy dentate volunteers. The studies were single, blind, randomised, crossover designs balanced for residual effects, with a minimum 2 1/2 day washout period. Salivary bacterial counts were determined before and to 7 h after a single rinse with the formulations. Plaque regrowth from a zero baseline (day 1) was measured by index and area on day 5, after 2x daily rinsing with slurries of the formulations or saline. For bacterial counts, highly significant treatment differences were found. Bacterial counts were variably reduced by all treatments to 30 min then showed a variable rate of return towards baseline. All test agents were significantly better than S at some timepoints. The order for greatest persistence of action downwards was; (1) SFSP2; (2) SFSP1, G, and SF1; (3) SF2; (4) C; (5) S. Highly significant differences in plaque regrowth between treatments were found with similar mean ordering of efficacy as for salivary bacterial counts from most effective downwards namely; (1) SFSP1 and SFSP2; (2) SF1; (3) SF2; G and C; (4) S. The results were consistent with a parallel study measuring tea staining in vitro, whereby formulations causing the most staining produced the greatest persistence of action and plaque inhibitory activity. This suggests the availability of stannous ions was important for the clinical effects. It is concluded that stannous ions can enhance the plaque inhibitory action of toothpaste via a persistent antimicrobial action.

Clinical efficacy of an optimized stannous fluoride dentifrice, Part 4: A 3-month calculus clinical study, northwest USA.

The objective of this 3-month, double-blind study was to investigate the efficacy of Colgate Optimized Stannous Fluoride (COSF) dentifrice for the control of supragingival dental calculus accumulation. After 3 months' use, the COSF dentifrice group exhibited a statistically significant 56.6% reduction in supragingival calculus formation, as compared to the control dentifrice group. The results of this study support the conclusion that the COSF dentifrice is efficacious for controlling the accumulation of supragingival calculus.

Clinical efficacy of an optimized stannous fluoride dentifrice, Part 5: A 3-month study of extrinsic tooth staining, northeast USA.

The objective of this 3-month, double-blind clinical study was to investigate the level of tooth staining associated with the use of Colgate Optimized Stannous Fluoride (COSF) dentifrice compared to the tooth staining associated with two commercially available dentifrices. The results of this clinical study support the conclusion that the intensity and extent of extrinsic tooth stain associated with the use of the COSF dentifrice are significantly lower than that associated with Crest Gum Care Toothpaste. Further, this study provided no indication that the use of the COSF dentifrice is associated with a greater level of stain than that associated with the use of Crest Regular Toothpaste, a standard 0.243% sodium fluoride/silica dentifrice.

Clinical efficacy of an optimized stannous fluoride dentifrice, Part 2: A 6-month plaque/gingivitis clinical study, northeast USA.

The objective of this 6-month, double-blind clinical study, conducted following the American Dental Association guidelines, was to investigate the efficacy of Colgate Optimized Stannous Fluoride (COSF) dentifrice for the control of supragingival dental plaque and gingivitis. This dentifrice contains 0.454% stannous fluoride, stannous chloride, polyphosphate, and citrate in a silica base. At the 3- and 6-month study examinations, the COSF dentifrice group exhibited statistically significant reductions in both plaque and gingivitis compared to the control dentifrice group. At the 6-month examination, the magnitude of these percent reductions exceeded 20% for all 4 parameters measured. Thus, the results of this study support the conclusion that the COSF dentifrice is efficacious for the control of supragingival plaque and gingivitis.

Clinical efficacy of an optimized stannous fluoride dentifrice, Part 3: A 6-month plaque/gingivitis clinical study, southeast USA.

This 6-month, double-blind clinical study, also following the American Dental Association guidelines, investigated the efficacy of Colgate Optimized Stannous Fluoride (COSF) dentifrice in controlling supragingival dental plaque and gingivitis. The same dentifrice, containing 0.454% stannous fluoride, stannous chloride, polyphosphate, and citrate in a silica base was used. Adult men and women from the Atlanta, Georgia, area received an oral prophylaxis and were instructed to brush their teeth twice daily (morning and evening) for 1 minute with their assigned dentifrice, using a soft-bristled toothbrush. As in the first study, plaque and gingivitis examinations were conducted after 3 months and again after 6 months of using the dentifrices. At both the 3- and 6-month study examinations, the COSF dentifrice group exhibited statistically significant reductions in both plaque and gingivitis compared to the control dentifrice group. At the 6-month examination, the magnitude of these percent reductions exceeded 20% for all 4 parameters measured. Thus, the results of this study reflect those found in the New Jersey study, i.e., supporting the conclusion that the COSF dentifrice is efficacious for the control of supragingival plaque and gingivitis.

The scientific rationale and development of an optimized stannous fluoride dentifrice, Part 1.

Stannous fluoride has been recognized as an effective anticavity therapeutic agent since the early 1950s. There has recently been a resurgence in activity to discover ways to fully exploit its documented antimicrobial activity. Through the use of targeted in vitro methodology to predict in vivo efficacy, a highly optimized stannous fluoride dentifrice has been developed. Careful selection of stabilizing agents formulated into a unique system has resulted in a Colgate Optimized Stannous Fluoride (COSF) dentifrice that has been proven to simultaneously help control supragingival plaque, gingivitis, supragingival calculus, and caries. Furthermore, the COSF dentifrice has been clinically shown not to cause the traditional stannous fluoride staining of dentition.

Does impedance cardiography reliably estimate left ventricular ejection fraction?

OBJECTIVE: The objective of our study was to evaluate impedance cardiography (IMP) as a noninvasive method to determine the left ventricular ejection fraction (LVEF). METHODS. A total of 24 patients, 8 men and 16 women, aged 45.0 +/- 12.9 years, participated in the study. They used cardiotoxic chemotherapeutic drugs or suffered from cardiac failure. LVEF was measured by means of IMP (LVEFimp) and radionuclide ventriculography (LVEFnuc). LVEFimp was calculated in three ways. Capan and colleagues [13] proposed a formula in which LVEF (LVEFCap) can be calculated from the systolic time intervals, namely, left ventricular ejection time and preejection time. Judy and colleagues [14] described a systolic (S) and a diastolic (D) part in the first derivative curve of the impedance signal. The ratio S/D might equal the LVEF (LVEFJud). A new LVEF calculation was introduced (LVEFimp) in this study based on the first derivative of the impedance signal, the thoracic impedance, and heart rate. RESULTS: Mean LVEFCap was 59.9 +/- 8.4%, which did not differ from LVEFnuc (59.9 +/- 7.1%). However the correlation between both methods was not significant (r = 0.29). Mean LVEFJud was 63.9 +/- 17.4%, which was not significantly different from LVEFnuc, with a fair correlation (r = 0.55). Mean LVEFimp was 59.2 +/- 9.4%, with a better correlation with radionuclide ventriculography (r = 0.75). CONCLUSIONS: The results of this study indicate that the equations that have been used until now can be improved. The new equation provides reliable LVEF values in this group of patients.

Technetium-labelled red blood cell scintigraphy: is it useful in acute lower gastrointestinal bleeding?

Radionuclide scintigraphy is commonly utilized as a screening examination before performing more invasive procedures in the work-up of patients with lower gastrointestinal (GI) bleeding. We reviewed our institutional experience with technetium-labelled red blood cell scintigraphy (TRCS) in detecting and localising acute lower GI bleeding. The study group included 72 patients who had 80 red cells scans over a five year period. Thirty-eight scans were positive (47.5%), and 42 were negative (52.5%). Sites of lower GI bleeding were confirmed by endoscopy, arteriography, surgery and/or pathology in 22 of the 38 positive scans. There were four false-negative scans (9.5%). The overall sensitivity and specificity of TRCS in detecting lower GI bleeding was 84.6% (22/26) and 70.4% (38/54), respectively. The accuracy of localization of bleeding sites in the patients with confirmed positive scans was 72.7% (16/22). Thirty mesenteric arteriograms were performed on patients in this series. Eleven arteriograms were performed after negative TRCS; one was positive. Technetium-labelled red blood cell scintigraphy appears to be a useful screening examination for patients with lower GI bleeding who are hemodynamically stable. This may avoid the potential morbidity of arteriography in patients who are not actively bleeding.