A cutoff thyroglobulin value suggestive of distant metastases in differentiated thyroid cancer patients.

Serum thyroglobulin is used as part of the early postoperative assessment of differentiated thyroid cancer (DTC) since there is a clear relationship between an increased risk of recurrence and persistent disease after initial treatment and high postoperative stimulated thyroglobulin (ps-Tg) values. Thus, although ps-Tg above 10-30 ng/mL is considered an independent predictor of worse prognosis, the value that is associated with distant metastases is not defined. Thus, this was our objective. We selected 655 DTC patients from a nuclear medicine department database (Irmandade Santa Casa de Misericórdia de São Paulo, Brazil). All patients had received total thyroidectomy and radioactive iodine (RAI) therapy and had ps-Tg values higher than 10 ng/mL with negative anti-thyroglobulin antibodies. Then, we selected patients who presented post-therapy whole-body scan with pulmonary and/or bone uptake but with no mediastinum or cervical uptake. Patients with negative findings on functional imaging or any doubt on lung/bone uptake were submitted to additional exams to exclude another non-thyroid tumor. Of the 655 patients, 14.3% had pulmonary and 4.4% bone metastases. There was a significant difference in ps-Tg levels between patients with and without metastases (P<0.001). The cutoff value of ps-Tg was 117.5 ng/mL (sensitivity: 70.2%; specificity: 71.7%) for those with lung metastasis, and 150.5 ng/mL (sensitivity: 79.3%; specificity: 85%) for those with bone metastasis. The cutoff value for patients with eitherpulmonary or bone metastasis was 117.5 ng/mL (sensitivity: 70.2%; specificity: 83.7%). Our findings demonstrated that ps-Tg could predict distant metastasis in DTC patients. We identified a cutoff of 117.5 ng/mL with a high negative predictive value of 93.7%.

A cutoff thyroglobulin value suggestive of distant metastases in differentiated thyroid cancer patients

Serum thyroglobulin is used as part of the early postoperative assessment of differentiated thyroid cancer (DTC) since there is a clear relationship between an increased risk of recurrence and persistent disease after initial treatment and high postoperative stimulated thyroglobulin (ps-Tg) values. Thus, although ps-Tg above 10-30 ng/mL is considered an independent predictor of worse prognosis, the value that is associated with distant metastases is not defined. Thus, this was our objective. We selected 655 DTC patients from a nuclear medicine department database (Irmandade Santa Casa de Misericórdia de São Paulo, Brazil). All patients had received total thyroidectomy and radioactive iodine (RAI) therapy and had ps-Tg values higher than 10 ng/mL with negative anti-thyroglobulin antibodies. Then, we selected patients who presented post-therapy whole-body scan with pulmonary and/or bone uptake but with no mediastinum or cervical uptake. Patients with negative findings on functional imaging or any doubt on lung/bone uptake were submitted to additional exams to exclude another non-thyroid tumor. Of the 655 patients, 14.3% had pulmonary and 4.4% bone metastases. There was a significant difference in ps-Tg levels between patients with and without metastases (P<0.001). The cutoff value of ps-Tg was 117.5 ng/mL (sensitivity: 70.2%; specificity: 71.7%) for those with lung metastasis, and 150.5 ng/mL (sensitivity: 79.3%; specificity: 85%) for those with bone metastasis. The cutoff value for patients with eitherpulmonary or bone metastasis was 117.5 ng/mL (sensitivity: 70.2%; specificity: 83.7%). Our findings demonstrated that ps-Tg could predict distant metastasis in DTC patients. We identified a cutoff of 117.5 ng/mL with a high negative predictive value of 93.7%.

The use of 99mTc-phytate for sentinel node mapping in melanoma, breast cancer and vulvar cancer: a study of 100 cases.

Sentinel node mapping reduces surgical morbidity and allows the use of more accurate tumour staging techniques. Radionuclide studies are preferentially performed using small colloids, which have limited availability in our country. The possibility of using phytate for sentinel node mapping was raised because of the similarity between its biodistribution and that of nanocolloids in the reticulo-endothelial system. In this paper we evaluated the use of 99mTc-phytate for sentinel node mapping, correlating the histopathological results with the status of the rest of the lymph node chain in different malignant tumours. A total of 100 patients were studied. group 1 consisted of 62 patients with breast cancer, group 2 of 20 patients with melanoma and group 3 of 18 patients with vulvar carcinoma. Lymph node scintigraphy was carried out after injecting 99mTc-phytate subdermally, and the sentinel node projection was marked on the skin. After 18-24 h, intraoperative sentinel node localisation was performed using a gamma probe (combined with visual localisation using patent blue dye) in 75 patients, and lymph node dissection was then carried out. Radionuclide scintigraphy identified the sentinel node in 98% of all studies. Intraoperative detection using the gamma probe was equally efficient: group 1=93% (38/41), group 2=95% (18/19) and group 3=100% (15/15). The sentinel node was involved in 41%, 31% and 20% of cases in groups 1, 2 and 3, respectively. Among the patients with positive nodes, the sentinel node was the only one affected in 53% of group 1, 50% of group 2 and 67% of group 3 cases. The method's negative predictive value was 91% in group 1 and 100% in the other groups. One false-negative study occurred in a patient who had a multifocal tumour and an intraparenchymatous lymph node; another occurred in a patient with a macroscopically affected node found during surgery. There were no side-effects related to the 99mTc-phytate. It is concluded that scintigraphic and intraoperative sentinel node identification was satisfactorily performed using 99mTc-phytate. The results were comparable to those previously described in the literature using other radiopharmaceuticals. Easy availability and low cost justify the use of phytate in our practice.

The use of (99m)Tc-phytate for sentinel node mapping in melanoma, breast cancer and vulvar cancer: a study of 100 cases.

Sentinel node mapping reduces surgical morbidity and allows the use of more accurate tumour staging techniques. Radionuclide studies are preferentially performed using small colloids, which have limited availability in our country. The possibility of using phytate for sentinel node mapping was raised because of the similarity between its biodistribution and that of nanocolloids in the reticulo-endothelial system. In this paper we evaluated the use of (99m)Tc-phytate for sentinel node mapping, correlating the histopathological results with the status of the rest of the lymph node chain in different malignant tumours. A total of 100 patients were studied. group 1 consisted of 62 patients with breast cancer, group 2 of 20 patients with melanoma and group 3 of 18 patients with vulvar carcinoma. Lymph node scintigraphy was carried out after injecting (99m)Tc-phytate subdermally, and the sentinel node projection was marked on the skin. After 18-24 h, intraoperative sentinel node localisation was performed using a gamma probe (combined with visual localisation using patent blue dye) in 75 patients, and lymph node dissection was then carried out. Radionuclide scintigraphy identified the sentinel node in 98% of all studies. Intraoperative detection using the gamma probe was equally efficient: group 1=93% (38/41), group 2=95% (18/19) and group 3=100% (15/15). The sentinel node was involved in 41%, 31% and 20% of cases in groups 1, 2 and 3, respectively. Among the patients with positive nodes, the sentinel node was the only one affected in 53% of group 1, 50% of group 2 and 67% of group 3 cases. The method's negative predictive value was 91% in group 1 and 100% in the other groups. One false-negative study occurred in a patient who had a multifocal tumour and an intraparenchymatous lymph node; another occurred in a patient with a macroscopically affected node found during surgery. There were no side-effects related to the (99m)Tc-phytate. It is concluded that scintigraphic and intraoperative sentinel node identification was satisfactorily performed using (99m)Tc-phytate. The results were comparable to those previously described in the literature using other radiopharmaceuticals. Easy availability and low cost justify the use of phytate in our practice.

Morphometric dual-energy X-ray absorptiometry of the spine: report of a large series and correlation with axial bone mineral density.

We studied vertebral morphometry and its relation to bone mineral density (BMD) in normal Brazilian women (n = 605). All women (age 22-97 years) were ambulatory and healthy. A lateral spine scan was done for morphometric X-ray absorptiometry using an imaging densitometer. In 429 of these women, BMD of the spine and proximal femur also were measured using dual-energy X-ray absorptiometry. All women were white with mean (+/- 1 SD) age of 53.7 (+/- 9.5) years. About 21% of the women over 50 years had a T score for spine BMD lower than -2.5 SD, and 7% had a femoral neck BMD below this osteoporosis threshold. Vertebral heights (anterior, HA; middle, HM; and posterior, HP) and ratios (HA/HP and HM/HP) were assessed. There was no systematic difference between younger (20-49 years) and older (50+ years) women in heights or ratios. The vertebral heights were normalized for those observed in each individual case for the L2-L4 sequence. This normalization was adequate for all vertebral heights; the Z score averaged about +0.1. The average Z score for HA/HP was +0.01, but that for the HM/HP was -0.72, indicating that the latter ratio might differ from the reference population used (white American and European women). We observed a small positive correlation between vertebral heights and spine or femur BMD, but this was due entirely to the influence of body size on BMD. On a group basis, the HM/HP showed a significant association with axial BMD; the 1 SD difference between the lowest and highest quartile was associated with a difference of 8-15% (0.5-1.0 SD) in axial BMD.

Use of radioiodine urinalysis for effective thyroid blocking in the first few hours post exposure.

A useful correlation between maximum thyroid uptake and radioiodine urine levels at different times after exposure was developed in order to determine when the intervention with an adequate blocking agent might still be effective. In an animal model (dog), six different doses were administered in the range of 100-600 kBq. The best correlation was found between the 125I uptake after 48 h (T-48) and urine radioactivity 4-6 h (U-4, U-5, U-6) after exposure. For the case of U-4, the equation Y(T-48) = 0.790 X(U-4) + 2.973 (r = 0.974 with a level of significance of p < 0.001) was obtained. An analogous study, carried out in humans (n = 20) to whom 1311 was administered, showed a similar correlation and level of significance: Y(T-24) = 1.162 X(U-4)+3.263 (r = 0.926; p < 0.001). The validity of this correlation was confirmed in four volunteers who received small doses of 125I(25-100 kBq), with good agreement between measured and extrapolated thyroid uptake and a mean difference of less than 10% (CV = 16.2%). Three different blocking agents were then tested in the same dog: potassium iodide, potassium perchlorate, and a thionamide (Tapazole). The blocking action of the first two compounds was about 90%, as opposed to only 48% for the third compound. Potassium iodide was chosen for its limited side effects and more universal utilization. The final study, carried out with four different doses, indicated that 25 mg of KI is the ideal amount to be administered to the dog. This corresponds to approximately 100 mg for a 70 kg human being (i.e., 1.4 mg kg(-1)). This dose, when administered to a volunteer 4 h after exposure, provided a thyroid blocking of 68%.

Densidade mineral óssea vertebral e femoral de 724 mulheres brancas brasileiras: influência da idade e do peso corporal / Vertebral and femoral bone mineral sessity of 724 caucasian Brazilian woman: influence of age and body weight

Objetivo. Estudar a densidade mineral óssea (BMD) vertebral (L2-L4) e femoral (colo do fêmur) de mulheres brancas, normais. Material e Método. Mediu-se o BMD de 724 mulheres (40-79 Kg; 20-69 anos de idade) por dual-energy x-ray absorptiometry e analisaram-se os dados em funçao da idade e peso corporal (PC). Resultados. As mulheres mais leves (40-49 Kg) atingiram o BMD maximo (BMDm) vertebral e femoral aos 30-39 anos de idade, enquanto as mais pesadas (60-79 Kg) apresentaram BMDm aos 20 anos. No fêmur, houve uma correlaçao significativa entre BMDm e PC (r=0,97, p<0,001; slope=0,72 por cento/Kg). Em L2-L4, apenas as mulheres com 40-49Kg apresentaram BMDm menor do que as demais(p<0,001). A diminuiçao do BMD vertebral foi mais intensa (-8,3 vs. -5,7 por cento/década) e iniciou mais cedo (quarta vs. quinta década) nas mulheres pesando 40-59Kg do que nas pesando 60-79Kg. A diminuiçao do BMD femoral iniciou logo após o BMDm ser atingido e, até os 69 anos, as mulheres mais pesadas apresentaram um decréscimo 5,3 por cento menor do que aquelas pesando 40-49Kg. O BMD vertebral das mulheres brasileiras foi praticamente o mesmo de uma populaçao norte-americana previamente descrita. Conclusoes. 1) O BMD vertebral e femoral das brasileiras estudadas comportou-se, em funçao da idade, de forma semelhante a de outras populaçoes brancas; 2) havendo o cuidado de corrigir o PC, o BMD das mulheres brasileiras é comparavel ao de mulheres norte-americanas; e 3) o PC é importante na aquisiçao e diminuiçao da massa óssea, além de influenciar a relaçao BMD-idade.

[Vertebral and femoral bone mineral density of 724 caucasian Brazilian women: influence of age and body weight]. / Densidade mineral óssea vertebral e femoral de 724 mulheres brancas brasileiras: influência da idade e do peso corporal.

OBJECTIVE: To study the vertebral (L2-L4) and femoral (neck) bone mineral density (BMD) of normal white women. MATERIAL AND METHOD: We measured the BMD of 724 women (40-79 kg; 20-69 years-age) by dual-energy X-ray absorptiometry. Data were analysed as a function of age and body weight (BW). RESULTS: Thinner women (40-49 kg) attained maximal vertebral and femoral BMD (mBMD) at ages between 30-39 years, while heavier women (60-79 kg) already had the mBMD by the age of 20. At the femur, there was a significant mBMD-BW correlation (r = 0.97; p < 0.001; slope = 0.72%/kg). At the spine, only the 40-49 Kg women exhibited lower mBMD when compared to the others (p < 0.001). The decrease of the vertebral BMD was more intense (-8.3 vs. -5.7%/decade) and started earlier (fourth vs. fifth decade) in women weighting 40-59 kg, as compared to those weighting 60-79 kg. The decrease of the femoral BMD was initiated just after mBMD was achieved and, at the age of 69, heavier women showed a decrease that was 5.3% lower than those weighting 40-49 kg. The vertebral BMD of the Brazilian women was practically the same as reported for a North-American population. CONCLUSIONS: (i) Vertebral and femoral BMD of this Brazilian population varied with age similarly to other white female populations; (ii) provided that appropriate corrections are made for BW, the BMD of Brazilian women is comparable to the BMD of North-Americans; and (iii) the BW is important both in acquisition and decline of bone mass, as it influences the relation BMD-age.

Influence of body composition on the bone mass of postmenopausal women.

AIMS: To investigate the influence of body weight (BW), fat mass (FM) and lean mass (LM) on the bone mineral density (BMD) of several areas of the skeleton. PARTICIPANTS: Sixty one white postmenopausal women (50.1 +/- 4.8 years). MEASUREMENTS: Measurement of BMD by dual energy x-ray absorptiometry. The results were analyzed by linear regression and the slopes of each curve were compared. RESULTS: The results showed that the correlations between BW, FM and LM to BMD were positive, whilst the correlations between age and years since menopause to BMD were negative. LM was the main factor that influence BMD in almost all areas. CONCLUSIONS: FM and LM present a positive effect on BMD, although LM is the main determinant of bone mass. Moreover, higher values of LM and FM present a protective effect against the reduction of BMD combined with menopause. Therefore postmenopausal women with low BW, especially low LM, present serious risk for developing osteoporosis.

Estimation of body fat and lean tissue distribution by dual energy X-ray absorptiometry and abdominal body fat evaluation by computed tomography in Cushing's disease.

Body composition determined by dual energy x-ray absorptiometry and the abdominal visceral fat component determined by computed tomographic scanning were examined in women with Cushing's disease and compared with those in obese women with the same anthropometric parameters and those in nonobese women. Patients with Cushing's had no increase in total body fat or the trunk region (android) component, but had a higher intraabdominal fat area compared to the obese subjects. The total lean tissue mass was slightly reduced in Cushing's compared to that in the obese subjects due to a significant decrease in the muscle of the legs and arms; the reduced amounts of fat and lean tissue masses in the arms were the most significant findings in hypercortisolism. The body mineral and bone calcium contents were slightly reduced in Cushing's compared to those in the obese controls. Thus, although obese subjects had more fat and lean tissue and mineral masses than their normal weight counterparts, the Cushing's patients, with the same total fat mass and its components (except in the arms) as obese individuals, present total lean tissue and fractions, including body mineral and bone calcium contents, similar to those in nonobese subjects due to the depletion of the protein depots, as seen in hypercortisolism.

[Basedow-Graves' disease: analysis of various parameters in the prognosis of remission after clinical treatment]. / Doença de Basedow-Graves: análise de diferentes parâmetros na previsão de remissão após tratamento clínico.

Fifty patients with Graves' disease were evaluated in relation to their outcome following medical treatment: goiter size, T3/T4 ratio, TSH and TSAb plasma levels were studied. Patients were followed for 8-20 months of medical treatment with PTU and 24-36 months thereafter. Thirty patients were eliminated for abandoning treatment (50%) or due to PTU side-effects (10%). The 20 patients remaining presented similar remission/relapse rates regardless of their T3/T4 ratio, greater than 20 (21% vs. 79%) or less than 20 (16% vs. 84%). Patients with TSH levels greater than 0.10 uU/ml immediately after PTU withdrawal presented a slight increase of remission rate (30% vs. 10%). Patients with goiter size greater than 60 cm3 at the beginning of medical treatment presented a remission rate of 8%, while those with goiters less than or equal to 60 cm3 showed a remission rate of 50%. Finally, normalization of TSAb levels (less than 15%) occurred at a remission rate of 100%, while all patients who did not achieve this goal relapsed shortly after PTU withdrawal. Based on these results, the authors conclude that the determination of TSAb levels is a reliable parameter of predict remission of Graves' disease following medical treatment.

[Diagnosis of osteoporosis using dual photon densitometry]. / Diagnóstico de osteoporose através da densitometria de dois fótons.

Osteoporosis is often diagnosed after fracture occurrence, when therapy is less effective. The dual photon densitometry has been the proposed method for osteoporosis early diagnosis. In the present study is presented our experience on the lumbar vertebral and femoral neck bone mass measurement by utilizing a Lunar DP-3 densitometer in normal young 82 volunteers and 103 women with radiologically and clinically diagnosed osteoporosis. The values found in osteoporotical patients were significantly lower when compared to those normals either in lumbar vertebrae (L2-L4) or in the femoral neck. The method's coefficient of variation was less than 0.5%, when determinated with a synthetic phantom aid and less than 1.5% repeating the exam in 10 normal volunteers. These results show that dual photon densitometry is a simple, sensitive and non-invasible method for early diagnosis and therapeutic follow-up of osteoporotical patients.

Conversao de tiroxina (T4) em 3,5,3'triiodotironina (T3) e 3,3',5-triiodotironina (reverso T3) em suspensoes de leucocitos humanos. Estudo nos estados de hiper e hipotiroidismo. / Thyroxine (T4) to 3,5,3'-triiodothyronine (T3) and 3,3',5-triiodothyronine (reserve T3) conversion in human leukocyte suspensions. Study in hyper and hypothyroidism states

O metabilismo periferico dos hormonios tiroidianos foi estudado em suspensoes de leucocitos humanos, determinando-se, por radioimunoensaio, agestao in vitro de T3 e rT3 a partir de T4 nao radioativo. Pode-se evidenciar, nas suspensoes de leucocitos provenientes de pacientes portadores de hipertiroidismo, maior geracao in vitro de T3 e rT3, enquanto que diminuicao significativa foi observada nos pacientes com hipotiroidismo. Essas alteracoes sao aparentemente devidas ao excesso e a falta de hormonios tiroidianos, respectivamente, ja que em ambos os casos elas puderam ser revertidas pelo tratamento clinico adequado