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Biomedical subjects

F Pons

Publications and source records attributed to F Pons.

250 records · Page 14Linked to original sources
PubMedDate not supplied

Dystrophin and dystrophin-related protein (utrophin) distribution in normal and dystrophin-deficient skeletal muscles.

The respective localizations of dystrophin and dystrophin-related protein (DRP or utrophin) along the sarcolemmal membrane and at the neuromuscular junctions (NMJs) in normal and dystrophin-deficient skeletal muscles, were determined using confocal laser microscopy. The analysis was prompted by the recent availability of a new anti-utrophin mAb [Bewick et al. NeuroReport 1992; 3:857-860] and different mAbs that react with dystrphin or both dystrophin and utrophin. In dystrophin-deficient muscles, utrophin was expressed and detectable over large subcellular areas normally occupied by dystrophin along the sarcolemmal membranes and at the NMJs. Utrophin was expressed in a non-uniform, discontinuous way on the sarcolemmal membrane in dystrophin-deficient skeletal muscles, similar to dystrophin in normal muscle fibres. The respective distributions of both related muscle proteins and their positions relative to the alpha-bungarotoxin acetylcholine (ACh) receptor marker were determined. Double-staining experiments and superimposition of the confocal images showed that utrophin was more closely associated with ACh receptors than dystrophin at the NMJs in normal muscles. Utrophin distribution consequently differed from that of dystrophin.

Adolescent↗
PubMedDate not supplied

[Fast method of labelling leukocytes with 99mTc HM PAO].

OBJECTIVE: To modify the method of labelling leukocytes with 99mTc HM-PAO by centrifuging 15 minutes at low gravity (g) instead of sedimentation at a variable time (30-90 minutes) to obtain leukocytic rich plasma (LRP). METHODS: The g number recovering the greatest number of leukocytes was determined. The cellular composition of LRP obtained by centrifugation and sedimentation was analyzed. Lastly, labelling results in two groups of patients (p) were compared: one group of 118 p using the traditional sedimentation method (SM) and another of 124 p using the proposed centrifugation alternative (CM). RESULTS: Centrifugation at 5xg produced the greatest recovery of leukocytes (93.1 5.1%). No significant difference was observed in leukocyte recovery in LRP obtained either by centrifugation or by sedimentation. However, red blood cell contamination was greater in centrifugation (12.8 4.9 x 108) than in sedimentation (7.7 3.5 x 108) (p < 0.0001). The comparison of the SM and the CM gave the following results:The number of leukocytes recovered in both methods was similar (73.9 15.1% vs 76.5 12.7%) with approximately the same platelet contamination (8.0 6.2 vs 8.4 6.5%). The number of red blood cell contaminants per leukocyte was 3.0 1.0 for the MS and 5.1 2.6 for the MC (p < 0.001). Labelling yield (LY) was somewhat higher for the CM (57.8 11.9%) than for the SM (50.8 12.6%) as a result of greater red blood cell contamination and superior radiochemical purity of the 99mTc HM-PAO used in the labelling by CM (90,9 5,9%) with regard to the SM (87.9 9.5%). No difference was observed in the scintigraphic images obtained with either of the methods, given the scarce uptake of the radiopharmaceutical by the red blood cells (3-7%) in comparison with the leukocyte uptake (70-90%). CONCLUSION: The proposed MC considerably reduces the labelling time of leukocytes with 99mTc HM-PAO without affecting the quality of scintigraphic images and represents an important labelling alternative of great interest to the Radiopharmacy Units of Nuclear Medicine Services.

Blood Cell Count↗
PubMedDate not supplied

[Comparative study of the different radiotracer administration route to locate the sentinel node in breast cancer].

AIM: To assess the results of Sentinel Lymph Node (SLN) detection in breast cancer patients depending on the radiotracer injection route, especially evaluating which route that makes it possible to identify the highest percentage of SLNs and its detection in the inner mammary chain. METHODS: We prospectively studied 120 breast cancer patients. Three groups of 40 patients each were established depending on the radiotracer injection route. 1) Subdermal or subareolar route: 18 T1 and 22 T2, mean tumor diameter size of 1.76 cm. 2) Peritumoral route: 16 T1 and 24 T2, mean tumor diameter size of 1.86 cm. 3) Intratumoral route: 20 T1 and 20 T2, mean tumor diameter size of 1.61 cm. The day before surgery, a lymphoscintigraphic study was performed in all cases and intraoperative SLN resection was carried out with the aid of a hand-held gamma probe. RESULTS: The SLN was identified in 38/40 cases (95%) of group 1, in 35/40 cases (88%) of group 2 and in 38/40 cases (95%) of group 3. No SLNs in the mammary chain were observed in patients who underwent subdermal/subareolar injection of the radiotracer. On the other hand, SLNs were visualized in this location in 4/35 patients with peritumoral injection (11%) and in 8/38 patients with intratumoral injection (21%). CONCLUSION: The superficial (subdermal, subareolar) injection technique is more suitable when an unnecessary lymphadenectomy has to be prevented in cases without axillary metastases. The deeper injection technique (peritumoral, intratumoral) should be use when, moreover, we seek accurate staging or plan non-systematic mammary chain irradiation.

Adult↗
PubMedDate not supplied

[Usefulness of the sentinel node in the treatment and staging of initial cervix cancer].

OBJECTIVE: The aim of this study was to evaluate the usefulness of intraoperative sentinel node (SN) detection in patients with initial cervix cancer. PATIENTS AND METHODS: Lymphoscintigraphy and intraoperative SN detection was performed in 17 patients with initial cervix cancer who we going to have a radical laparoscopic hysterectomy and pelvic lymphadenectomy. Conization was performed in 4/17. The day before surgery, an injection of 111 MBq 99mtechnetium nanocolloid around the primary tumour and a subsequent lymphoscintigraphy were carried out. Blue dye was injected at the same location intraoperatively. A laparoscopic gamma probe was used to identify SNs. RESULTS: SNs were successfully localized using a combination of radiocolloid and blue dye in 16/17 patients (detection rate 94 %). The detection rate only using blue dye technique decreases to 71 % (12/17) and it reaches an 82 % (14/17) if we avoid the blue dye injection. In 3 cases, there was no migration in lymphoscintigraphy and in one of the three SN could not be detected. Thirty-three SNs were identified (1.9 nodes/patient). The most frequent location was left external iliac nodal group (13 nodes: 39 %). SNs were identified in regions that are not included in usual lymphadenectomy: right parametrium (2 sentinel nodes, one of them in the retrouterine region), and interiliac (2 SNs). In all four patients with previous conization SNs were identified (detection rate 100 %). CONCLUSIONS: The rate of SN detection combining lymphoscintigraphy with gamma probe and blue dye is 82 %. The use of blue dye allows increasing this rate to 94 % in those cases which migration was not seen or when the SN is placed near the injection site. The SN technique offers the possibility to find SNs in regions not included in usual lymphadenectomy.

Adult↗
PubMedDate not supplied

[Psoas abscess as cause of lumbar spine pain detected by scintigraphy with gallium in a patient with suspicion of spondylodiscitis].

A 56 year old man with fever and lumbar pain who underwent an abdominal CT scan that showed lumbar arthrosic changes, although it was not possible to rule out infectious disease in L5/S1. Bone scintigraphy was requested. It showed heterogeneous hyperuptake that did not make it possible to exclude a spondylodiscitis in this site. Scintigraphy with 67Ga-citrate excluded infectious diseases in the lumbar spine column. However, a pathological uptake was observed in the left iliac fossa suggestive of psoas abscess, which was confirmed by ultrasonography, isolating streptococcus viridans.

Citrates↗
PubMedDate not supplied

[Ovarian and para-aortic recurrence from cervix cancer detected by PET/CT].

We present the case of a 34-year-old woman diagnosed of an adenosquamous carcinoma of the uterine cervix, stage IIB of the FIGO classification (International Federation of Gynecology and Obstetrics), treated with quimiotherapy, radiotheraphy and brachytheraphy with posterior hysterectomy. A recurrence of the disease was suspected due to the progressive rise of CEA levels. A PET/CT revealed abnormal foci in both ovaries, that had been transposed to avoid lesions due to radiation, and in a left para-aortic adenopathy. The diagnosis of recurrence in these sites was confirmed by biopsy. PET with FDG (F18-fluorodeoxyglucose) is useful in the staging of primary tumour and in the detection of recurrence in uterine cervical carcinoma, with better sensitivity and specificity than CT and MRI. PET/CT improves anatomic resolution and helps to resolve the origin of unclear foci like in the case presented in which ovaries were not in their normal situation due to transposition.

Adult↗
PubMedDate not supplied

Pregnancy associated osteoporosis: the familial effect.

OBJECTIVE: The etiology and pathogenesis of pregnancy associated osteoporosis is unclear. Whether pregnancy has simply been an aggravating factor or is a direct etiologic cause responsible for severe bone loss needs to be elucidated. METHODS: In order to evaluate the contribution of familial factors to pregnancy osteoporosis, we analyzed the bone mass of 15 relatives of 5 women with pregnancy osteoporosis. Most of the patients suffered from severe back pain associated with vertebral fractures in their first pregnancy. Extensive clinical, laboratory and radiological investigations were performed to exclude secondary causes of osteoporosis. Bone mineral density measurements were performed on 15 first order family members and the results were compared with those of a control group of 20 healthy members of 5 families. RESULTS: Osteoporosis was present in 53% of the relatives of patients with pregnancy osteoporosis and in 15% of the controls (P < 0.05). CONCLUSION: These results highly suggest that some patients with pregnancy associated osteoporosis have a genetic determination of low peak bone mass, and gestation, due to its association with physiological metabolic disturbances, constitutes a risk factor for the development of skeletal fractures in these patients.

Absorptiometry, Photon↗
PubMedDate not supplied

Action of platelet-activating factor (PAF) antagonists on the bronchopulmonary effects of PAF in the guinea-pig.

Intravenous injection of BN 52021 in anesthetized guinea-pigs, 5 min before challenge, inhibited in a dose-dependent fashion with an IC50 of 0.90 mg/kg the bronchoconstriction induced by PAF (60 ng/kg i.v.). However, BN 52021 did not prevent the leukopenia following PAF injection but significantly inhibited the thrombocytopenia induced by PAF. The dioxolan compound, BN 52111, dose-dependently reduced the bronchoconstriction (IC50 = 0.27 mg/kg) and at doses higher than 1 mg/kg partially antagonized the decrease in the number of circulating platelets and leukocytes induced by PAF. BN 52115 also markedly inhibited the bronchoconstriction (IC50 = 0.36 mg/kg) as well as the thrombocytopenia induced by PAF, but was without significant effect on the leukopenia. These results demonstrate that the two dioxolan compounds, BN 52111 and BN 52115, are more potent than BN 52021 in inhibiting the in vivo bronchopulmonary alterations induced by PAF. Since these alterations are related to the activation of platelets by the autacoid, these blood elements are probably the targets of BN 52111 and BN 52115. Injection of PAF (10 and 100 ng) via the pulmonary artery of ventilated and perfused guinea-pig lungs induced dose-dependent increases in pulmonary inflation pressure (PIP) and pulmonary perfusion pressure (PPP), associated with a dose-dependent release of thromboxane B2 (TxB2). Addition of BN 52021, BN 52111 or BN 52115 (0.1, 1 or 10 microM) to the perfusion medium, 15 min before challenge, dose-dependently inhibited the bronchopulmonary effects of PAF. Although BN 52111 was the more potent in inhibiting the PAF-induced increase in PIP, BN 52021 was the more active with respect to the PAF-evoked generation of TxB2, suggesting that the two phenomena are not directly related.

Animals↗