Luiz Querino de Araújo Caldas

Bio: Luiz Querino de Araújo Caldas is an academic researcher from Federal Fluminense University. The author has contributed to research in topics: Uncaria tomentosa & Ginkgo biloba. The author has an hindex of 6, co-authored 18 publications receiving 116 citations.

Effect of oral ingestion of an extract of the herb Uncaria tomentosa on the biodistribution of sodium pertechnetate in rats

Abstract: The aim of the present study was to determine the effect of the oral ingestion of an extract of the herb Uncaria tomentosa (cat's claw) on the biodistribution of the radiobiocomplex sodium pertechnetate (Na99mTcO4) in rats. The animals (male Wistar rats, 2 months old, 180-220 g), were treated (1 mL) with an U. tomentosa extract (32 mg/mL, N = 5) or 0.9% NaCl solution (control, N = 5) for 7 days. After this period, Na99mTcO4 (3.7 MBq, 0.3 mL) was injected through the ocular plexus and after 10 min the rats were killed, the organs isolated and counted in a well-gamma counter. A significant (P < 0.05) alteration in Na99mTcO4 uptake i) from 0.57 +/- 0.008 to 0.39 +/- 0.06 %ATI/organ (P < 0.05) and from 0.57 +/- 0.17 to 0.39 +/- 0.14 %ATI/g (P < 0.05) was observed in the heart, ii) from 0.07 +/- 0.02 to 0.19 +/- 0.07 %ATI/g in the pancreas, and iii) from 0.07 +/- 0.01 to 0.18 +/- 0.07 %ATI/g (P < 0.05) in muscle after treatment with this extract. Although these results were obtained with animals, caution is advisable in the interpretation of the nuclear medicine examination when the patient is using this herb. This finding is probably an example of drug interaction with a radiopharmaceutical, a fact that could lead to misdiagnosis of the examination in clinical practice with unexpected consequences for the patient.

Bioavailability of the sodium pertechnetate and morphometry of organs isolated from rats: study of possible pharmacokinetic interactions of a ginkgo biloba extract

Abstract: Many compounds affect the bioavailability of radiobiocomplexes as radiopharmaceuticals. Ginkgo Biloba extract (EGb) has several effects. The influence of an EGb on the bioavailability of the radiobiocomplex sodium pertechnetate (Na99mTcO4) and on the morphometry of the organs was evaluated. Rats were treated with EGb and Na99mTcO4 was injected. The animals were sacrificed; the radioactivity in the organs was counted. The results showed that EGb altered the Na99mTcO4 bioavailability in the kidneys, liver and duodenum. Morphometric analysis of the organs showed significant alterations (P<0.05), probably caused by metabolites generated by EGb and capable of altering the bioavailability of the Na99mTcO4.

Strategies for reducing airborne pesticides under tropical conditions

Abstract: Brazil is currently one of the largest pesticide consumers worldwide. However, a lack of scientific information regarding airborne pollution is still an issue, with tragic consequences to human health and the environment. To reduce pollution of the lower air layers, where pesticide spraying occurs, green barriers that filter the air could be an effective mitigation procedure. Modifying pulverization habits, by pulverizing in the late afternoon instead of in the morning could also reduce pesticide volatilization, while other recommendations with the purpose of lowering the pesticide amounts currently applied are likewise pursued. Data obtained about volatilization have demonstrated that, in order to reduce air pollution risks, one of the most effective preventive strategies is to ban products with high vapor pressure. Global/local stakeholders need to assume the responsibility to find the best way to reduce airborne pesticide pollution, which has increasingly shown disastrous effects as major poisons to human health and the environment.

The ingestion of a Nectandra membranacea extract changes the bioavailability of technetium-99m radiobiocomplex in rat organs.

Abstract: The radiobiocomplexes labeled with technetium-99m (Tc-99m) have been widely used in nuclear medicine insingle photon emission computed tomography and in basic research. The aim of this study was to assess theinfluence of a Nectandra membranacea extract on the bioavailability of the sodium pertechnetate(Na 99m TcO 4 ) radiobiocomplex in rat organs. The animals were treated with a N. membranacea extract (30 mg/ml), for 6 days. Na 99m TcO 4 was injected, the organs were isolated and weighed, and the radioactivity wasdetermined in each organ (%ATI/organ). The %ATI/organ was divided by the mass of each organ to calculatethe %ATI/g. A significant increase of the %ATI/organ of Na 99m TcO 4 was observed in muscle and thyroid aswell as in the %ATI/g in the heart, kidney and thyroid. These findings could result from the interactionbetween components of the plant extract and the radiobiocomplex which may influence the uptake Na 99m TcO 4 in rat organs. Therefore, precaution is suggested in the interpretation of nuclear medicine results in patientsusing this herb.

Metals and Neurodegeneration.

Abstract: Metals play important roles in the human body, maintaining cell structure and regulating gene expression, neurotransmission, and antioxidant response, to name a few. However, excessive metal accumulation in the nervous system may be toxic, inducing oxidative stress, disrupting mitochondrial function, and impairing the activity of numerous enzymes. Damage caused by metal accumulation may result in permanent injuries, including severe neurological disorders. Epidemiological and clinical studies have shown a strong correlation between aberrant metal exposure and a number of neurological diseases, including Alzheimer’s disease, amyotrophic lateral sclerosis, autism spectrum disorders, Guillain–Barre disease, Gulf War syndrome, Huntington’s disease, multiple sclerosis, Parkinson’s disease, and Wilson’s disease. Here, we briefly survey the literature relating to the role of metals in neurodegeneration.

Technetium-99m Pharmaceuticals: Preparation and Quality Control in Nuclear Medicine

Abstract: I. Zolle, ed. New York, NY: Springer, 2007, 345 pages, $169 Written by a panel of 21 experts in the field and edited by Ilse Zolle, this hardbound volume is the current authoritative desk reference for those working with 99mTc-labeled radiopharmaceuticals. The 11 chapters of part 1 provide