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

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.

In vivo antibacterial effect of tin on the oral microflora.

The antibacterial effect of oral rinses with stannous fluoride and stannous chloride solutions, and of the use of a toothpaste containing stannous fluoride and stannous pyrophosphate was tested by recording the bacterial viable counts on the oral mucous membrane. Stannous chloride had no antibacterial effect, while stannous fluoride drastically reduced the viable counts up to 4 h. Calculations demonstrated that 25% of the tin content in 10 ml rinsing solutions was retained in the mouth, and analyses showed a raised tin level in saliva up to 4 h after rinsing or toothbrushing. It is suggested that most of the retained tin is bound to the oral mucosa.

Failure in labelling of red blood cells with 99mTc: interaction between intravenous cannulae and stannous pyrophosphate.

The effect of different methods of stannous pyrophosphate (SnPYP) administration on a modified in vivo technique for labelling red blood cells (RBCs) with 99mTc has been studied. Retention of 99mTc in the bloodstream was measured and parallel in vitro RBC labelling experiments were performed. After administration of SnPYP or a mixture of SnPYP and heparin via the metal needles of intravenous cannulae, the mean 30-min retentions of 99mTc were 96.8% (SD 8.6) and 95.3% (SD 12.4) respectively and the mean in vitro labelling efficiencies were 86.9% (SD 5.0) and 81.9% (SD 18.2) respectively. When the SnPYP was administered via teflon cannulae, the mean 30-min retention of 99mTc was 40.0% (SD 16.7) and the in vitro labelling efficiency was 18.7% (SD 27.0). Reduced RBC labelling and rapid clearance of 99mTc from the bloodstream were not explained by adsorption of stannous ion or pyrophosphate onto the teflon cannulae or retention of SnPYP in the cannulae. When labelling RBCs with 99mTc it is important that SnPYP is not injected via a teflon cannula.

Modifying effect of commercially available stannous pyrophosphate (PYRO-Sn) on the tissue affinity of 99mTc pertechnetate.

Investigations were performed to examine the conditions required for in vivo labelling of red blood cells (RBCs) with 99mTc after injection of stannous pyrophosphate. It was found that good in vivo labelling of RBCs is possible and that the efficacy of this procedure is high. The highest concentration of 99mTc in the blood occurred in the first 2 h after pertechnetate injection, and the optimum time between stannous pyrophosphate and pertechnetate injection ranged from 10 to 30 min.

In vivo labeling of red blood cells with Tc-99m with stannous pyridoxylideneaminates.

Several stannous pyridoxylideneaminates were evaluated as stannous ion sources for the in vivo labeling of red blood cells (RBCs) with Tc-99m. In spite of a considerable variety of stannous preparations, rapid and efficient RBC labeling was obtained with each stannous chelate. These results suggest that the role of the ligands is merely to stabilize the divalent state of the tin. The optimal time interval between Sn(II) and 99mTcO4- injections, and the best stannous-ion concentration, was found using stannous pyridoxylideneisoleucine (Sn-P.isoL). Maximal in vivo labeling of the RBCs was obtained with an i.v. dose of 10-20 micrograms Sn(II)/kg of Sn-P.isoL followed 15-30 min later by i.v. administration of pertechnetate.