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M Rodrigues

Publications and source records attributed to M Rodrigues.

At least 37 records · Page 2Linked to original sources
PubMed2000

Use of 99mTc-furifosmin scintigraphy--planar and SPECT--to evaluate suggestive palpable and nonpalpable breast lesions.

UNLABELLED: Our objective was to evaluate the role of 99mTc-furifosmin scintigraphy--planar and SPECT--in discriminating benign from malignant breast disease. METHODS: The trial was prospective, open, and diagnostic. We recruited 30 consecutive patients with 14 palpable and 16 nonpalpable breast lesions. After receiving informed consent, we injected 555-640 MBq 99mTc-furifosmin intravenously in the arm contralateral to the breast lesion. Planar imaging and SPECT were performed. All patients underwent excision of the tumor within 2 wk. Using histology as the gold standard, we calculated sensitivity, specificity, and positive and negative predictive values for 99mTc-furifosmin in planar and SPECT technique. RESULTS: For 18 malignant and 12 benign breast lesions, a sensitivity of 50% for planar imaging and 72% for SPECT was seen. Specificity and positive and negative predictive values were 83%, 82%, and 53%, respectively, for planar imaging and 50%, 68%, and 55%, respectively, for SPECT. For the 14 palpable tumors (10 malignant, 4 benign), which averaged 17+/-10 mm in size (size range, 4-45 mm), a sensitivity of 60% for planar imaging and 80% for SPECT was achieved. Sixteen lesions were not palpable (median size, 9+/-3 mm [size range, 4-13 mm]). In this subgroup, 99mTc-furifosmin scintigraphy yielded a sensitivity of 37% for planar and 62% for SPECT technique (P>0.05). CONCLUSION: 99mTc-furifosmin scintigraphy is not a potent competitor to established scintigraphic procedures. In comparing this tracer with 99mTc-sestamibi and 99mTc-tetrofosmin, we cannot recommend 99mTc-furifosmin for the diagnosis of breast cancer.

Breast Diseases↗
PubMed2000

Uptake of 99mTc-MIBI and 99mTc-tetrofosmin into malignant versus nonmalignant breast cell lines.

UNLABELLED: The kinetics and cellular uptake of 99mTc-2-hexakis 2-methoxyiso-butyl-isonitrile (MIBI) and 99mTc-1 ,2-bis[bis(2-ethoxyethyl)phosphino]ethane (tetrofosmin) into malignant versus nonmalignant human breast cell lines were investigated and compared. METHODS: At specific intervals after incubation at 37 degrees C and 22 degrees C with 99mTc-MIBI or 99mTc-tetrofosmin, the uptake characteristics of radiotracers into human adenocarcinoma breast cell lines MCF-7 and SK-BR-3 and human breast, nontumor cell line HBL-100 were assessed. RESULTS: The uptake of 99mTc-MIBI and 99mTc-tetrofosmin was lower at an incubation temperature of 22 degrees C than that at 37 degrees C in the 3 cell lines. In MCF-7 and in SK-BR-3 cells the uptake of 99mTc-MIBI was significantly higher than the uptake of 99mTc-tetrofosmin. The uptake of 99mTc-MIBI was significantly higher into MCF-7 and SK-BR-3 cells than that into HBL-100 cells. In comparison with HBL-100 cells, uptake of 99mTc-tetrofosmin into SK-BR-3 cells was significantly higher, whereas uptake into MCF-7 cells was similar. CONCLUSION: In vitro data suggest that 99mTc-MIBI may be a better tracer than 99mTc-tetrofosmin for discrimination between malignant and nonmalignant breast disease.

Adenocarcinoma↗
PubMed1999

Examination of co-complexes for radiolabeling of platelets in positron emission tomographic studies.

Oxine, tropolonate, and mercaptopyridine-N-oxide (MPO) have been widely used with 111In for platelet labeling. The use of positron emission tomography (PET) radioisotopes for platelet labeling would offer a higher sensitivity and resolution over conventional imaging. The medium half-life PET radioisotope 55Co (t1/2 = 18.2 hours) would enable quantitative uptake and cell kinetic studies with radiolabeled platelets. To identify the optimal complex for radiolabeling of platelets with 55Co, we investigated the platelet uptake of 57Co-oxine, 57Co-tropolonate, and 57Co-MPO in varying different parameters. The platelet uptake of Co-complexes was generally low (5-12%), dependent on time and temperature of incubation and density of platelets but independent of the amount of radioactivity. These findings are not promising for potential PET application.

Adult↗
PubMed1999

A head-to-head comparison between technetium-99m-tetrofosmin and technetium-99m-MIBI scintigraphy to evaluate suspicious breast lesions.

The aim of this study was to assess the diagnostic value of technetium-99m-tetrofosmin and technetium-99m-MIBI in a head-to-head comparison. Both radiopharmaceuticals are routinely used for detecting breast cancer. In a prospective, open, diagnostic trial, the two radiopharmaceuticals were administered randomly on different days to the same 101 women suffering from 103 breast tumours. Planar images and single photon emission computer tomography (SPET) were performed. After histological examination of the tumours, sensitivity, specificity and positive and negative predictive value were compared. 99mTc-tetrofosmin and 99mTc-MIBI showed low sensitivity in planar images (44% vs 46%, respectively). SPET improved sensitivity (70% vs 69%, respectively). Specificity in planar images was 83% and 87%, and it was even lower using SPET (70% vs 78%, respectively). Positive predictive value in planar images was 76% vs 81%, and it was not changed by SPET. Negative predictive value was low in planar images (54% vs 57%, respectively), but it was improved by using SPET (65% vs 67%, respectively). In conclusion, 99mTc-tetrofosmin and 99mTc-MIBI scintigraphy show similar diagnostic value in assessing suspicious breast lesions.

Adult↗
PubMed1999

Platelet labeling with 67Ga chelates.

68Ga-labeled platelets could be useful for positron emission tomographic (PET) studies. In order to identify the optimal chelate for radiolabeling of platelets with 68Ga, we investigated the platelet uptake of 67Ga-oxine, -tropolone and -MPO. The platelet uptake of 67Ga-oxine and -tropolone is very low (< 5%). The platelet uptake of 67Ga-MPO, in contrast, increases with platelet density (highest at 10(9) platelets/ml) up to 18%. Our data provide evidence that only 68Ga-MPO could be useful for PET-studies.

Adult↗
PubMed1999

Presence of PGE1 binding determines the erectile response to PGE1.

The clinical benefit of PGE1 in erectile dysfunction in men is well proven, while other species including non-human primates show almost no response. The reason for that difference is still unclear. We examined PGE1 binding in human surgical material (n=27) and from transsexual surgery (n=7) as well as rhesus (n=10) and cynomolgus monkeys (n=8) corpus cavernosum tissue. Erection was judged after intracavernous injection of PGE1 in men (10 microg) and in monkeys (5 microg). Human corpus cavernosum shows high- (binding capacity 24.7+/-3.3 pmol/mg protein) and low-affinity (binding capacity 77.4+/-7.3 pmol/mg protein) PGE1 binding sites. Oestrogen (3 mg/day) for more than one month before transsexual surgery decreases receptor density significantly. In rhesus and cynomolgus monkeys no high-affinity binding could be detected, while they respond on PGE1 with slight tumescence only. These findings indicate a significant correlation between corpus cavernosum PGE1 receptor density and the erectile response.

Adult↗
PubMed1999

Influence of etoposide on the retention of radiolabeled low-density lipoprotein in the arterial wall.

BACKGROUND: Cardiovascular toxicity of chemotherapy for testicular cancer is a matter of discussion, since highly efficient agents can achieve cure of the disease, even in the metastasized setting. Acute ischemic events during the treatment period and a persistently elevated serum cholesterol thereafter are observations of particular concern in these patients, and the underlying basic mechanisms are unknown to date. OBJECTIVE: To evaluate etoposide, which is part of the standard treatment for testicular cancer, as a potential cause of atherogenesis in an experimental model. SETTING: Aortic 125I-labeled low-density lipoprotein retention was studied in 72 cholesterol-fed rabbits under etoposide treatment and was quantified according to the morphologically assessed type of surface lining. Aortic cholesterol content was determined both by Sudan III staining and quantitatively by a biochemical assay. RESULTS: A reduced uptake of 125I-labeled low-density lipoprotein in the arterial wall was observed in the etoposide-treated animals, which resulted in a size reduction of sudanophilic areas and cholesterol content. Whereas the breakdown of 125I-labeled low-density lipoprotein in the liver was not significantly enhanced, the plasma decay of 125I-labeled low-density lipoprotein was faster and serum cholesterol was lower in the etoposide group than in controls. CONCLUSION: Unexpectedly, we found an improvement of arterial wall lipid metabolism under etoposide treatment and can thus exclude this substance as a promoter of atherogenesis in this model.

Animals↗
PubMed1998

Use of a leishmanin skin test in the detection of canine Leishmania-specific cellular immunity.

The leishmanin skin test was used to detect Leishmania-specific cellular immunity in asymptomatic dogs from an endemic region of visceral leishmaniosis. The test was safe since no clinical signs of intolerance to leishmanin were detected during 1 month, in 14 dogs after inoculations of 3 x 10(8) promastigotes/ml. In another group of four dogs no cross reactivity was found after inoculations of a PPD which demonstrated the specificity of the test. In the same group of animals, repeatability was assessed by repeated inoculations of leishmanin at 1-5-month intervals and the threshold of sensitivity was the concentration of 3 x 10(6) promastigotes/ml. Secondly, we applied the test in a dog population that live in an endemic region of visceral leishmaniosis and found a significant increase in Leishmania-infected dogs after the application of this test in the field.

Animals↗
PubMed1998

Accumulation of platelets as a key mechanism of human erection.

In this study, the role of platelets in the human erectile response was assessed. Twenty patients with erectile dysfunction were studied by means of (111)In-oxine-platelets and blood pool imaging using 99mTc. Seventeen patients received intracavernously prostaglandin E1, and three patients received papaverine together with phentolamine. In patients who responded with erection, an increase by between 16 to 137% platelets/ml and a rapid platelet accumulation in the penis during the initial phase of erection were observed. In patients without erection, no change in local platelet concentration occurred. It is likely that platelets play a major role in human erection, probably by temporary activation, thereby regulating venous outflow.

Adult↗
PubMed1998

No relationship between territory size and the risk of cuckoldry in birds.

It has been suggested that male birds adjust their territory size in order to prevent potential intruders from gaining extra-pair copulations. The risk of cuckoldry is supposed to be highest when the distance between a female and the neighbouring males is shortest. This paper describes the variation in territory size of the chiffchaff, Phylloscopus collybita, in relation to the breeding cycle. Contrary to the risk of cuckoldry hypothesis, chiffchaff territories were larger prior to the fertile period of the females and at a minimal size during the fertile period. A review of the literature shows little, if any, evidence of a peak in territory size during the fertile period of the females for most species studied. It is suggested that territoriality is in need of an operational definition. Without such a definition, it is difficult to make and test predictions about the adaptive basis of variation in territory size. Copyright 1998 The Association for the Study of Animal Behaviour. Copyright 1998 The Association for the Study of Animal Behaviour.

Journal Article↗
PubMed1998

Prostaglandins as biochemical markers of radiation injury to the salivary glands after iodine-131 therapy?

Because salivary glands, as well as thyroid tissue, are able to concentrate radioiodine, the treatment of thyroid diseases with iodine-131 may have secondary effects on salivary gland function which seriously impair the quality of life. Such effects include sialoadenitis and xerostomia. Salivary secretion is stimulated by prostaglandins (PGs). In this study we evaluate whether 131I therapy influences the levels of PGs in saliva. Patients who had previously received 131I for treatment of hyperthyroidism or differentiated thyroid cancer and healthy volunteers were studied. Levels of PGs [6-oxo-PGF1 alpha, bicyclo-PGEm, thromboxane B2 (TXB2), PGF2 alpha] in unstimulated saliva were measured using enzyme immunoassay. Significantly lower levels of 6-oxo-PGF1 alpha, bicyclo-PGEm and PGF2 alpha and higher levels of TXB2 were found in the group of patients in comparison with the controls. Differences between patients and controls were more pronounced in smokers. This study demonstrates that salivary gland uptake of 131I significantly affects PG levels in saliva.

Adult↗
PubMed1998

Pure red cell aplasia due to persistent B19 parvovirus infection in patient infected with human immunodeficiency virus type 1. Recovery with alpha-interferon therapy.

B19 parvovirus (PV) infection is ordinarily resolved with the production of specific antibodies that neutralize virus infectivity for erythroid host cells. Nevertheless persistent infection with B19 PV and pure red blood cell aplasia have been documented. A 27 year-old male. i.v. drug abuser, HIV+ and HCV was diagnosed of pure red cell aplasia. Six months later we had serologic evidence of persistent parvovirus infection. Interferon therapy, started for HCV infection, showed a marked improvement of anaemia and anti parvovirus IgM became negative. It is discussed the possible role of interferon therapy in persistent parvovirus infection.

Adult↗