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

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 percent 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 percentATI/organ (P < 0.05) and from 0.57 ± 0.17 to 0.39 ± 0.14 percentATI/g (P < 0.05) was observed in the heart, ii) from 0.07 ± 0.02 to 0.19 ± 0.07 percentATI/g in the pancreas, and iii) from 0.07 ± 0.01 to 0.18 ± 0.07 percentATI/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.

Is the infertility in hypothyroidism mainly due to ovarian or pituitary functional changes?

The objective of the present study was to examine whether hypothyroidism affects the reproductive system of adult female rats by evaluating ovarian morphology, uterus weight and the changes in serum and pituitary concentrations of prolactin and gonadotropins. Three-month-old female rats were divided into three groups: control (N = 10), hypothyroid (N = 10), treated with 0.05 percent 6-propyl-2-thiouracil (PTU) in drinking water for 60 days, and T4-treated group (N = 10), receiving daily sc injections of L-thyroxine (0.8 æg/100 g body weight) during the last 10 days of the experiment. At the end of 50 days of hypothyroidism no hypothyroid animal showed a regular cycle, while 71 percent of controls as well as the T4-treated rats showed regular cycles. Corpora lutea, growing follicles and mature Graafian follicles were found in all ovaries studied. The corpora lutea were smaller in both the hypothyroid and T4-replaced rats. Graafian follicles were found in 72 percent of controls and only in 34 percent of hypothyroid and 43 percent of T4-treated animals. Serum LH, FSH, progesterone and estradiol concentrations did not differ among the three groups. Serum prolactin concentration and the pituitary content of the three hormones studied were higher in the hypothyroid animals compared to control. T4 treatment restored serum prolactin concentration to the level found in controls, but only partially normalized the pituitary content of gonadotropins and prolactin. In conclusion, the morphological changes caused by hypothyroidism can be a consequence of higher prolactin production that can block the secretion and action of gonadotropins, being the main cause of the changes observed

Autoradiographic thyroid evaluation in short-term experimental diabetes mellitus

Previous studies have shown that in vitro thyroid peroxidase (TPO) iodide oxidation activity is decreased and thyroid T4-5' -deiodinase activity is increased 15 days after induction of experimental diabetes mellitus (DM). In the present study we used thyroid histoautoradiography, an indirect assay of in vivo TPO activity, to determine the possible parallelism between the in vitro and in vivo changes induced by experimental DM. DM was induced in male Wistar rats (about 250 g body weight) by a single ip streptozotocin injection (45 mg/kg), while control c animals received a single injection of the vehicle. Seven and 30 days after diabetes induction, each diabetic and control animal was given ip a tracer dose of I (2 muCi), 2.5 h before thyroid excision. The glands were counted, weighed, fixed in Bouin's solution, embedded in paraffin and cut. The sections were stained with HE and exposed to NTB-2 emulsion (Kodak). The autohistograms were developed and the quantitative distribution of silver grains was evaluated with a computerized image analyzer system. Thyroid radioiodine uptake was significantly decreased only after 30 days of DM (C:0.38 + 0.05 vs DM: 0.20 + 0.04 percent/mg thyroid, P<0.05) while in vivo TPO activity was significantly decreased 7 and 30 days after DM induction (C:5.3 and 4.5 grains/100 mum2 vs DM: 2.9 and 1.6 grains/100 mum2, respectively, P<0.05). These data suggest that insulin deficiency first reduces in vivo TPO activity during short-term experimental diabetes mellitus.

In vitro radioautographic studies of the biodistribution of radiopharmaceuticals on blood elements

In the present study evaluated the binding of the radiopharmaceuticals sodium pertechnetate (Na (99m)TcO4), methylenediphosphonic acid (99m)Tc-MDP)) and glucoheptonate acid (99m)Tc-GHA)) to blood elements using centrifugation and radioautographic techniques. Heparinized blood was incubated with the labelled compounds for 0, 1, 2, 3, 4, 6 and 24 h. Plasma (P) and blood cells (BC) were isolated and precipitated with 5 percent trichloroacetic acid (TCA), and soluble (SF) and isoluble fractions (IF) were separated. Blood samples were prepared (0 and 24 h) and coated with LM-1 radioautographic emulsions and percent radioactivity (percent rad) in P and BC was determined. The binding of Na (99m)TcO4 (percentrad) to P was 61.2 percent (0 h) and 46.0 percent (24 h), and radioautography showed 63.7 percent (0 h) and 43.3 percent (24 h). The binding to BC was 38.8 percent (0 h) and 54.0 percent (24 h), and radioautography showed 36.3 percent (0h) and 56.7 percent (24 h), and radioautography showed 36.3 percent (0 h) and 56.7 percent (24 h). (99m) Tc-MDP study presented 91.1 percent (0 h) to P and 87.2 percent (24 h), and radioautography showed 67.9 percent (0 h) and 67.4 percent (24 h). The binding to BC was 8.9 percent (0 h) and 12.8 percent (24 h), and radioautography showed 32.1 percent (0 h) and 32.6 percent (24 h). (99m)Tc-GHA study was 90.1 percent (0 h) to P and 79.9 percent (24 h), and radioautography showed 67.2 percent (0 h) and 60.1 percent (24 h). The binding to BC was 9.9 percent (0 h) and 20.1 percent (24 h), and radioautography showed 32.8 percent (0 h) and 39.9 percent (24 h). The comparasion of the obtained results suggests that the binding to plasma and blood cells in the two techniques used (radioautography and centrifugation) qualitatively in accordance.

Pressão arterial e grupos sociais. Estudo epidemiológico / Arterial blood pressure and social groups. Epidemiological study

Foram estudados 1773 homens, de 20 a 70 anos, pertencentes a 7 grupos sociais e profissionais: 200 medicos, 167 trabalhadores rurais, 151 indios, 218 operarios de industrias, 205 presidiarios, 699 pracas e 163 oficiais da Marinha. Das varias variaveis analisadas, a idade, a raca, o peso corporal, o estresse emocional, a historia familiar de hipertensao, os grupos sociais e profissionais tiveram correlacao estatisticamente significativa com os niveis pressoricos. Encontrou-se uma prevalencia de hipertensos da ordem de 16,1%. A maior taxa de hipertensao foi observada no grupo de presidiarios (26,3%) e a menor no de oficiais (6,7%). De modo geral, os grupos de nivel social mais baixo demonstraram maior prevalencia de hipertensao arterial. Do total de hipertensos, 72,4% ignoraram a enfermidade, apenas 16% estavam sob tratamento, e destes, somente a metade exibia niveis normais de pressao arterial.Apenas 1 em cada 12 hipertensos tinha sua hipertensao controlada por tratamento eficaz