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Biomedical subjects

F Pons

Publications and source records attributed to F Pons.

At least 73 records · Page 4Linked to original sources

Bone mineral density in young, hypothalamic oligoamenorrheic women treated with oral contraceptives.

OBJECTIVE: To evaluate whether decreasing doses of ethinyl estradiol affect bone loss related to hypothalamic amenorrhea. STUDY DESIGN: Sixty-four women with hypothalamic oligoamenorrhea were allocated to two therapy groups: group A (n = 24) received an OC containing 0.030 mg of ethinyl estradiol (EE) and 0.15 mg of desogestrel. Group B (n = 22) received an OC containing 0.020 mg of EE and 0.15 mg of desogestrel. Eighteen women who did not wish to use hormonal therapy constituted the control group (C). Calcium, phosphate and osteocalcin were measured basally and at 6 and 12 months of follow-up. Bone mineral density at the lumbar spine was determined before initiation of the study and at 12 months by dual energy X-ray absorptiometry. RESULTS: Serum calcium, phosphate and osteocalcin were significantly reduced by both active treatment regimens, whereas no differences were observed in the control group. Bone mineral density at 12 months showed an increase in both therapy groups (A, 2.4%; B, 2.5%), while group C showed a significant decrease (1.2%, P < .05). CONCLUSION: Both doses of EE were equally effective in preventing bone loss related to hypoestrogenism in hypothalamic oligoamenorrheic subjects.

Absorptiometry, Photon↗

Comparative effects of estrogens plus androgens and tibolone on bone, lipid pattern and sexuality in postmenopausal women.

BACKGROUND: The main goals of estrogen replacement therapy (ERT) are the prevention of osteoporosis and cardioprotection and the improvement of quality of life (QL). Androgens and tibolone therapy may increase bone mineral density (BMD) to a greater extent than ERT and offer an increase in QL. Lipid and cardiovascular effects, however, are still a major concern. AIM: To evaluate whether the addition of a weak androgen to ERT may improve postmenopausal bone loss and sexual activity without adverse effects on lipid pattern and to compare these effects with those observed after tibolone therapy. SUBJECTS AND METHODS: This prospective study enrolled 120 surgical postmenopausal women; of these, 96 completed the 1-year follow-up. Patients were allocated to one of four groups. The first group (A; n = 23) received 4 mg of estradiol valerate plus 200 mg of enanthate of dihydroandrosterone im monthly. The second group (E; n = 26) received 50 microg/day of transdermal 17-b-estradiol continuously; the third (T; n = 23) received 2.5 mg of tibolone every day; and finally, the fourth group (C; n = 24) constituted a treatment-free control group. Bone mass (dual X-ray absorptiometry), serum total cholesterol, HDL, LDL, triglycerides, apolipoproteins A1 and B and sexual activity were evaluated before starting therapy and at the end of follow-up. RESULTS: All active treatment groups showed an increase in BMD. This increase was higher in the A treatment group (4.08% P < 0.01). Sexuality improved significantly with therapy; however, tibolone and androgens increased scores to a greater extent than ERT. Androgen therapy was associated with significant increases in total cholesterol, LDL and triglycerides. Cholesterol and LDL fall into groups E and T, HDL into groups A and T and triglycerides in group T only. CONCLUSION: The combined regimen of androgens and ERT increased vertebral bone mass and enhance sexual activity in postmenopausal women equal to that of tibolone and to a greater extent than ERT alone; its effects on lipids, however, are clearly adverse.

Administration, Cutaneous↗

Quantitative analysis of relative protein contents by Western blotting: comparison of three members of the dystrophin-glycoprotein complex in slow and fast rat skeletal muscle.

We have developed a method for accurate quantitative analysis and statistical comparison of the relative contents of the dystrophin-glycoprotein complex (DGC) in skeletal muscle. This method was applied to compare DGC contents in slow (soleus) and in fast (extensor digitorum longus, EDL) rat skeletal muscles. The quantitative analysis combines a modified bicinchoninic acid (BCA) assay with Western blotting and enhanced chemiluminescence (ECL). This combination allows the use of high levels of detergents and reducing reagents essential for extracting DGC. In addition, the evaluation of the total amount of proteins in each sample makes it possible to have a reference and to accurately compare relative protein levels without using a specific standard. With a large gradient gel, we could concomitantly compare two groups (n = 9) and quantify all protein contents differing highly in their molecular masses (from 35 kDa to 427 kDa). Each experiment was triplicated and normalized; the two muscles were compared using the Mann-Whitney test (P<0.001) to establish their protein content. The DGC relative levels for the slow muscle soleus and the fast muscle EDL differed significantly: dystrophin, beta-dystroglycan, and gamma-sarcoglycan levels were 130%, 110% and 120% higher in the soleus, respectively. The differences observed in the expression level of cytoskeletal associated protein (dystrophin) and transmembranous anchorage components may correspond to a physiological response of the muscle fibers to duration, magnitude, and frequency of the imposed mechanical loading.

Animals↗

Inhalation of toluene diisocyanate affects cytochrome P450 2B1 expression in rat lung.

In the lung the expression of xenobiotic-metabolizing enzymes such as cytochromes P450 (CYP) and glutathione S-transferases (GST) may be affected by inhaled pollutants. Toluene diisocyanate (TDI) is a highly volatile chemical compound known to induce a wide array of diseases in workers exposed to vapors or sprays, including respiratory allergy and asthma. We investigated the effect of inhaled TDI on expression of CYP 1A1, 2B1, 2E1, and 3A1 and of alpha-, mu-, and pi-GST in rat lung. Animals were exposed to targeted concentrations of 0.01, 0.1, or 1 ppm TDI vapors or to cleaned filtered air for 8 h. Expression of CYP and GST was analyzed 18 24 h after the end of exposure using western blotting, northern blotting, and immunohistochemistry. Constitutive levels of CYP 2B1 and 3A1 proteins were found in lung tissue from control rats, whereas CYP 1A1 and 2E1 proteins were not detectable. Animal exposure to TDI vapors neither modified CYP 3A1 protein expression, nor led to any detectable expression of CYP 1A1 or 2E1. In contrast, exposure to 1 ppm TDI induced a 40% reduction in CYP 2B1 protein levels. This decrease was associated with a 33% decrease in CYP 2B1 mRNA levels. Additionally, CYP 2B1 immunolabeling localized to ciliated epithelial cells, Clara cells, and type II alveolar cells in the lung tissue of control rats was markedly decreased in animals exposed to 1 ppm TDI. Constitutive levels of alpha-, mu-, and pi-GST proteins were found in lung tissue from control rats. Exposure to TDI had no effect on lung expression of either of the GST. In conclusion, this study clearly shows a selective decrease in CYP 2B1 expression by TDI vapors in rat lung. The contribution of CYP 2B1 to metabolize further xenobiotics is therefore altered.

Administration, Inhalation↗

(99m)Tc-sestamibi scintigraphy and cell cycle in parathyroid glands of secondary hyperparathyroidism.

Double-phase parathyroid MIBI ((99m)Tc-sestamibi) was performed in 27 patients with secondary hyperparathyroidism (SPT). Focal areas of increased uptake were scored for intensity on a three-point scale. All patients underwent subtotal parathyroidectomy (SPTx), and a total of 78 glands were removed at operation. Blood was obtained from the jugular vein before and after SPTx to measure the parathyroid hormone (PTH) levels. The volume and weight of the glands were calculated. The tissue was divided, with one aliquot being used for cell cycle analysis. The nuclei were acquired by flow cytometry and analyzed using CELLEIT software. Cell viability was assessed by flow cytometry and analyzed with LYSIS II software. Positive MIBI uptake was observed in 88.8% of patients. Focal MIBI uptake of one, two, or three glands was observed in 6, 11, and 8 patients, respectively. All patients experienced an 86% decrease in PTH blood level after SPTx compared to that before excision. A correlation was found between the volume of glands and the blood levels of intact PTH (iPTH) (r = 0.5, p < 0.05). A positive correlation was observed between MIBI uptake and the iPTH levels before SPTx (p < 0.01) and between the uptake of MIBI in the parathyroid glands and the cell cycle phases; low-grade uptake correlated with the G(0) phase and higher uptake with G(2)+S phase (r = 7, p < 0.01). No correlation was observed between MIBI uptake and the weight of the glands. MIBI scintigraphy accurately reflects the functional status of the hyperplastic parathyroid glands: Higher uptake grades correlated with the active growth phase. MIBI uptake does not reveal parathyroid enlargement; rather, it identifies the presence of hyperfunctioning autonomous glands. SPTx and total parathyroidectomy with autografting (TPTx+A) are the most widely accepted surgical approaches for patients with SPT. Reoperation for recurrence is necessary in 6% to 15% of cases. MIBI is now considered to be the radionuclide of reference for parathyroid gland scanning, although it is widely accepted that it produces poor results when trying to detect hyperplastic glands.

Adult↗

Primary spontaneous pneumothorax: one-stage treatment by bilateral videothoracoscopy.

BACKGROUND: The goal of the study was to report our 7-year experience with single-stage bilateral videothoracoscopy for bleb excision and pleural abrasion in patients suffering primary spontaneous pneumothorax. METHODS: From November 1992 through June 1999, 12 men were operated on in our department. Preoperative chest computed tomographic scans were obtained for all patients. Operative indications included simultaneous bilateral pneumothorax (n = 2), contralateral recurrence (n = 1), ipsilateral recurrence with contralateral blebs or bullae, and job restrictions (n = 9). RESULTS: Mean age at operation was 26+/-6 years. All patients had multiple blebs or bullae located in upper lobes, and 4 patients (33%) had pleural adhesions. All blebs or bullae were resected at operation. The mean number of staple cartridges was 5 per patient (range, 3 to 8). All patients had bilateral pleurabrasion. There were no perioperative complications and no conversion to thoracotomy. The mean operative time was 168+/-17 minutes (range, 140 to 190 minutes). The mean drainage time was 5 days (range, 4 to 26 days) and the mean hospital stay was 7.7+/-1.4 days for 11 of 12 patients. Postoperative complications included prolonged air leak (16.5%), incomplete lung reexpansion (25%), and pleural effusion (8.5%). One patient required reoperation on the right side through transaxillary thoracotomy within 1 month of videothoracoscopy for pleurodesis failure. Follow-up was 100% complete. Mean follow-up is 50+/-34 months (range, 9 to 88 months) and no patient has had recurrence of pneumothorax. All patients except one returned to full occupational activity within 5 weeks of surgery. CONCLUSIONS: Single-stage bilateral videothoracoscopy for bilateral bleb excision and pleurabrasion is a safe procedure that does not result in major complications and provides excellent long-term results. This approach could be considered in young patients with bilateral primary spontaneous pneumothorax, or in those requiring radical therapy for the prevention of ipsilateral and contralateral recurrences.

Adolescent↗

Thoracoscopic excision of mediastinal bronchogenic cysts: results in 20 cases.

BACKGROUND: We present our experience with thoracoscopic resection of mediastinal bronchogenic cysts in adults. METHODS: From November 1990 to September 1993, 20 patients with mediastinal bronchogenic cysts were operated on by thoracoscopy. The average cyst size was 4.9 cm, and the largest diameter was 10 cm. Ten cysts were located in the middle mediastinum and 10 in the posterior mediastinum. Two cysts were complicated. RESULTS: Thirteen bronchogenic cysts were resected completely by thoracoscopy. We had to convert thoracoscopy into thoracotomy because of bleeding in two cases and because of major adhesions to vital structures in five cases. There were no operative deaths and no postoperative complications. Mean hospital stay was significantly less in the completely thoracoscopically treated group. Long-term follow-up (range, 4.5 to 7.5 years) showed no late complications and no recurrence. CONCLUSIONS: Preoperative complications, intraoperative injuries, and major adhesions to vital structures seem to be the only unfavorable conditions to thoracoscopic treatment of bronchogenic cysts. This study found encouraging results for thoracoscopic excision of mediastinal bronchogenic cysts in selected patients.

Adult↗

[Treatment of metastatic bone pain with repeated doses of strontium-89 in patients with prostate neoplasm].

This study has aimed to evaluate the usefulness of repeated treatment with 89Sr in patients with prostate neoplasm and metastatic bone pain. Seventeen patients with partial or complete response after the first dose were retreated with two or more doses (total of 39 doses). The Karnofsky functional status, pain and degree of analgesia were assessed. After the first dose the response was good in 68% of the patients and partial in 32%. After the second dose, the response was good in 62% of the patients, partial in 15% and there was no response in 23% of the cases. The pre-treatment Karnofsky functional status and duration of the effect of 89Sr was lower after the second dose (p = 0.03, p = 0.02), but there were no statistically significant differences in the type of response. In conclusion, re-treatment with 89Sr can be administered safely and with a similar response to that achieved after the first dose.

Aged↗

Components of biological variation of biochemical markers of bone turnover in Paget's bone disease.

The aims of this study were to evaluate the components of biological variation of the new markers of bone turnover in patients with Paget's bone disease and to compare the results with data obtained in healthy subjects. Fifteen patients with Paget's disease in a stable period of the disease and 12 healthy premenopausal women were included for a 1 year follow-up study. Within- and between-subject biological variation, indices of individuality, and critical differences were evaluated for the following biochemical markers: in serum, total (tAP), and bone (bAP) alkaline phosphatases, procollagen type I N-terminal propeptide (PINP) and beta-carboxyterminal telopeptide of type I collagen (sCTx); in urine, hydroxyproline (Hyp), and amino (NTx) and beta-carboxyterminal (CTx) telopeptides of collagen type I. Serum markers of bone turnover showed lower biological variability than urinary markers. Within-subject biological variation was higher in pagetic patients than in healthy subjects for all serum markers. In both groups, bAP presented the lowest within-subject biological variation. In pagetic patients, all markers presented indices of individuality of <0.6, indicating their usefulness for patient monitoring. Critical differences were lower for serum markers than for urinary markers. Among pagetic patients, serum bAP and PINP showed the lowest critical differences with values close to 30%, whereas urinary CTx presented the highest critical differences (near 70%). Conversely, in healthy subjects, tAP was the marker with the lowest critical differences, being two-fold higher in pagetic patients. This study confirms the lower sensitivity of urinary markers to detect significant changes and indicates that data obtained on biological variations from healthy populations cannot always be extrapolated to pathological conditions. In addition, serum bAP and PINP seem to be the markers that best reflect a significant change in activity of Paget's disease.

Adult↗

Collagen type Ialpha1 gene polymorphism in idiopathic osteoporosis in men.

OBJECTIVE: To analyse the distribution of polymorphism of the collagen type Ialpha1 gene (COL1A1) and its relationship with bone metabolism and bone turnover in men with idiopathic osteoporosis. METHODS: A total of 35 male patients with idiopathic osteoporosis, aged 50.4 +/- 10.3 yr, and 60 healthy males (controls), aged 47 +/- 17 yr, were included in the study. Serum osteocalcin, 25-hydroxyvitamin D and parathyroid hormone were determined in all patients. The COL1A1 Sp1 genotypes (SS, SS:, ss) were assessed by restriction enzyme digestion (BAL:1) of DNA amplified by the polymerase chain reaction. RESULTS: Patients with idiopathic osteoporosis had a higher frequency of the s allele than men in the control group (29 vs 11%, P: = 0.003) and a higher frequency of the SS: genotype (patients, 48% SS, 46% SS:, 6% ss; controls, 80% SS, 18% SS:, 2% ss; P: = 0.003). No significant differences between genotypes were observed in serum concentrations of osteocalcin, vitamin D or parathyroid hormone among either the patients or the controls. CONCLUSION: This study suggests that, in men with idiopathic osteoporosis, there is a high prevalence of the s allele and the SS: genotype that is unrelated to other parameters of bone metabolism.

Adult↗

Scintigraphic evolution of a breast cancer with Tc-99m MIBI scintimammography.

Early detection and prompt treatment of breast cancer are the main tools to decrease mortality rates. Several diagnostic techniques such as mammography, magnetic resonance imaging, and ultrasound are used, but none of these are conclusive. The authors describe a 56-year-old woman who was suspected of having breast cancer on mammography. Tc-99m MIBI scintimammography showed a small mass with elevated radiotracer uptake located near the pectoral muscle of the patient's left breast. The possible tumor was confirmed with fine-needle aspiration biopsy. After the diagnosis was established, the patient did not allow any treatment. Eighteen months later, a second scintimammography was performed, showing a large mammary tumor with a high radiotracer uptake, a new small lesion located in the left upper quadrant, and axillary lymph node involvement. Chemotherapy treatment was instituted and after treatment, Tc-99m MIBI scintimammography was normal. This case report provides further evidence for Tc-99m MIBI scintimammography for the detection of breast cancer as well as to evaluate the response to chemotherapy.

Antibiotics, Antineoplastic↗

Predictors of bone mineral density reduction in adolescents with anorexia nervosa.

OBJECTIVES: To determine which variables are associated with a significant reduction in bone mineral density (BMD) in adolescent anorexia nervosa and to establish guidelines for indication of bone densitometry. METHOD: One hundred seventy patients (treated from 1997 until 1999), aged 10 to 17 years, with a DSM-IV diagnosis of anorexia nervosa were evaluated by dual-energy-x-ray absorptiometry in the lumbar spine (L2-L4) and the femoral neck. The results were compared with the normative data for BMD values by age and sex in Spanish adolescents. RESULTS: 44.1% of patients had osteopenia at the lumbar spine and 24.7% at the femoral neck. The following variables were related to osteopenia: more than 12 months since onset of the disorder (p < .001), more than 6 months of amenorrhea (p < .001), body mass index <15 (p < .001), calcium intake <600 mg/day (p < .01), and <3 hours/week of physical activity (p < .001). In a stepwise logistic regression analysis to predict reduced spinal BMD, 3 variables-months elapsed since the onset of weight loss, calcium intake, and body mass index--correctly classified 78.8% of patients. CONCLUSIONS: Adolescent anorexia nervosa patients with the characteristics outlined above are at high risk of reduced BMD, and densitometry is recommended to determine the degree of osteopenia.

Absorptiometry, Photon↗

Usefulness of strontium-89 for bone pain palliation in metastatic breast cancer patients.

Most studies of prostate cancer have shown that strontium-89 chloride (89Sr) is effective in the palliation of metastatic bone pain, refractory to conventional analgesia. The aim of this study was to evaluate the usefulness of 89Sr for bone pain palliation in breast cancer patients. Forty women were treated with 148 MBq of 89Sr. Six patients were retreated, receiving two or more doses. The Karnofsky performance status was assessed and pain and analgesia were scored on scales of 9 and 5 points, respectively. The efficacy of 89Sr was evaluated at 3 months of treatment. The response was good in 60% of the patients and partial in 32%; there was no response in the remaining 8% (pre-treatment Karnofsky < or = 60). The duration of the response was 120+/-143 days. In the patients retreated, the response was good in 83% and partial in 17%, without significant differences compared with the first dose, but the pre-treatment Karnofsky and the duration of the efficacy were lower (P < 0.05). A transient and slight decrease of leukocyte and platelet counts after the first month of treatment with 59Sr was observed. In conclusion, breast cancer patients with metastatic bone pain can benefit from therapy with 89Sr. If necessary, the treatment may be repeated safely and with the same efficacy as is achieved after the first dose. A low functional performance status could be a cause of the lower effectiveness of 89Sr.

Aged↗

Myosin heavy chains in fibers of TTX-paralyzed rat soleus and medial gastrocnemius muscles.

The expression of five myosin heavy chain (MHC) isoforms was analyzed in the rat soleus (Sol) and the deep and superficial medial gastrocnemius (dGM, sGM) muscle after 2 and 4 wk of TTX paralysis by using immunohistochemical techniques. In Sol, after 4 wk of paralysis, fibers containing type I MHC were either pure type I (14%) or also contained developmental (D; 76%), IIa (26%), or IIx (18%) MHC. Values for corresponding fibers in dGM were 8.5, 65, 38, and 22%. Also, by 4 wk an increase was seen in the proportions of fibers expressing IIa MHC in Sol (from 16 to 38%) and dGM (from 24 to 74%). In a region of sGM in control muscles containing pure IIb fibers, a major proportion (86%) remained pure after 4 wk of paralysis, with the remainder coexpressing IIb and IIx. The results indicate that TTX-induced muscle paralysis results in an increase in fibers containing multiple MHC isoforms and that the D isoform appears in a major proportion of these hybrid fibers.

Animals↗