Psidium guajava (guava) leaf is a phytotherapic used in folk medicine to treat gastrointestinal and respiratory disturbances and is used as anti-inflammatory medicine. In nuclear medicine, blood constituents (BC) are labelled with technetium-99m ( 99m Tc) and used to image procedures. However, data have demonstrated that synthetic or natural drugs could modify the labelling of BC with 99m Tc. The aim of this work was to evaluate the effects of aqueous extract of guava leaves on the labelling of BC with 99m Tc. Blood samples of Wistar rats were incubated with different concentrations of guava extract and labelled with 99m Tc after the percentage of incorporated radioactivity (%ATI) in BC was determined. The results suggest that aqueous guava extract could present antioxidant action and/or alters the membrane structures involved in ion transport into cells, thus decreasing the radiolabelling of BC with 99m Tc. The data showed significant (P<0.05) alteration of ATI in BC from blood incubated with guava extract.

In clinical acupuncture, when acupuncture points are stimulated, several types of reflex responses can be evoked. Consequently, different categories of physiological responses are induced, which include changes in the activities of internal organs and tissues. The acupuncture point Sanyinjiao (SP6) has been used successfully to treat different human gastrointestinal conditions. The aim of this work was to investigate the effects of end-organ response induced by acupuncture point SP6 on the bioavailability of the radiopharmaceutical sodium pertechnetate (Na99mTcO4) in Wistar rats. Healthy rats were allocated into 2 groups, control-CG and treated-TG. TG was bilaterally stimulated at acupuncture point SP6 with stainless steel needles. Ocular plexus administration of Na99mTcO4 (3.7MBq) was carried out 10 min after every needle insertion in all animals. Ten minutes later, the animals were killed, the organs were isolated, the radioactivity was determined in a well gamma counter, and the percentage of injected dose per gram of tissue (%ID/g) was determined for each organ. The %ID/g was significantly altered (p < 0.05) in the small intestine of TG (0.56 +/- 0.09) when compared to CG (0.82 +/- 0.18). These results may suggest that this stimulation might induce physiological responses capable of altering the bioavailability of the radiopharmaceutical sodium pertechnetate. These findings aid in providing a better understanding of acupuncture and its effects on various organs and tissues.

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Since ancient times propolis has been employed for many human purposes because to their favourable properties. Blood constituents labeled with technetium-99m (99mTc) have been used in nuclear medicine procedures. Some authors have reported that synthetic or natural drugs can interfere with the labeling of blood constituents with 99mTc. The aim of this work was to evaluate the action of a propolis extract on the labeling of blood elements with 99mTc. Samples of whole blood of male Wistar rats were incubated in sequence with an aqueous propolis extract at different concentrations, stannous chloride and 99mTc, as sodium pertechnetate. Blood samples were centrifuged to separate plasma and blood cells, soluble and insoluble fractions of plasma and blood cells were also separated after precipitation in trichloroacetic acid solution and centrifugation. The radioactivity was counted and the percentage of incorporated radioactivity (%ATI) for each fraction was calculated. The data obtained showed that the aqueous propolis extract used decreased significantly the %ATI in plasma proteins at higher concentration studied. Results suggest that at high concentration the constituents of this extract could alter the labeling of plasma proteins competing with same binding sites of the 99mTc on the plasma proteins or acting as antioxidant compounds.

The use of natural products as medicines has been growing in the entire world. There are concerns that these products may contain potentially toxic ingredients and contaminants such as heavy metals. The labeling of blood constituents with technetium-99m has been influenced by the presence of natural extracts. We evaluated the influence of a chayotte (Sechium edule) extract (100% v/v macerated) on the labeling of blood elements with 99mTc. The animals were treated with the extract during 15 days. Samples of blood were carried out with specific blood biochemistry kits. The present study analyzed the influence ofchayotte in the survival of the strain of Escherichia coli AB1157 submitted to reactive oxygen species induced by stannous chloride. There was a reduction of the lethal effect induced by stannous chloride on the survival of the E. coli culture in the presence of chayotte. The results indicated a decrease in the level of glucose and globulin The effect of the extract could be explained by its metabolic transformation inducing the generation of oxidant metabolites. The culture of bacteria when was treated with stannous chloride and chayotte simultaneously, the extract could be reacting with stannous chloride ions, protecting them against the oxidation avoiding the generation of reactive oxygen species.

Stannous chloride (SnCl2) is used in nuclear medicine as a reducing agent to obtain technetium-99m-radiopharmaceuticals. It have been reported that natural products might reduce the genotoxic and cytotoxic effects related to SnCl2. This work evaluated the biological effects of an aqueous extract of Salix alba on the survival of Escherichia coli (E. coli) AB1157 (wild type) cultures submitted to the action of SnCl2. E. coli AB1157 cultures (exponential growth phase) were collected by centrifugation, washed and resuspended in 0.9%NaCl. Samples were incubated in water bath shaker with: (a) SnCl2 (25μg/ml), (b)Salix alba extract(11.6mg/ml) and (c)SnCl2(25μg/ml) + Salix alba extract (11.6mg/ml). Incubation with 0.9% NaCl was also carried out (control). At 60 min intervals, aliquots were withdrawn, diluted, spread onto Petri dishes with solid LB medium and incubated overnight. The colonies formed were counted and the survival fractions calculated. The extract was not able to protect the E. coli cultures against the lesive action of SnCl2. The extract also did not interfere with the survival of the cultures. It suggested that the substances present in the Salix alba aqueous extract did not interfere strongly with cellular metabolism and did not alter the survival fractions of E. coli AB1157. It is speculated that this extract cannot interfere with the generation of free radicals, the possible main agent responsible for SnCl2 lesive action.

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Experimental models have aided to understand the mechanism and the exercise effects on biological systems. To evaluate the effects of acute swimming exercise on the bioavailability of the radiopharmaceutical technetium-99m methylenediphosphonate ( 99m Tc-MDP) used for bone scintigraphy, the rats were divided into control, sedentary, and exercised groups. Sedentary and exercised groups were adapted to water for 2 weeks (5 min/day, 5 days/week). After that, the exercised groups (EG) were submitted to acute swimming exercise for 5, 10 or 20 min (loads of 5% of body weight), and then all animals were anaesthetized, 99m Tc-MDP was administered and after 180 min the animals were sacrificed. Blood and organs were removed, the radioactivity was determined in a well counter and the percentage per gram of tissue of injected dose (%ID/g) was calculated. The findings showed a significant decrease of %ID/g in the hearts of the sedentary group, EG-5min, EG-10min and EG-20min when compared to the control group, in the bones of EG-20min when compared to the control group, and in the lungs of EG-5min and EG-10min when compared to the control group. These findings could be associated with specific modifications of the metabolism in certain organs, which are highly relevant when evaluations of the bone using 99m Tc-MDP are being carried out.