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Biomedical subjects

M M Pinheiro

Publications and source records attributed to M M Pinheiro.

6 recordsLinked to original sources
PubMed2005

Prevalence of low trauma fractures in long-term kidney transplant patients with preserved renal function.

We evaluated the prevalence of low bone mineral density (BMD) and osteoporotic fractures in kidney transplantation (KT) patients and determined risk factors associated with osteoporotic fractures. The study was conducted on 191 patients (94 men and 97 women) with first KT for 3 years or more presenting stable and preserved renal function (serum creatinine levels lower than 2.5 mg/dl). KT patients were on immunosuppressive therapy and the cumulative doses of these drugs were also evaluated. BMD was determined by dual-energy X-ray absorptiometry at multiple sites (spine, femur and total body). Quantitative ultrasound of the calcaneus (broadband ultrasound attenuation, speed of sound, and stiffness index, SI) was also performed. Twenty-four percent (46) of all patients had either vertebral (29/46) or appendicular (17/46) fractures. We found osteoporosis and osteopenia in 8.5-13.4 and 30.9-35.1% of KT patients, respectively. Women had more fractures than men. In women, prevalent fractures were associated with diabetes mellitus [OR = 11.5, 95% CI (2.4-55.7)], time since menopause [OR = 3.7, 95% CI (1.2-11.9)], femoral neck BMD [OR = 1.99, 95% CI (1.4-2.8)], cumulative dose of steroids [OR = 1.1, 95% CI (1.02-1.12)] and low SI [OR = 1.1, 95% CI (1.0-1.2)]. In men, fractures were associated with lower lumbar spine BMD [OR = 1.75, 95% CI (1.1-2.7)], lower SI [OR = 1.1, 95% CI (1.03-1.13)], duration of dialysis [OR = 1.3, 95% CI (1.13-2.7)], and lower body mass index [OR = 1.24, 95% CI (1.1-1.4). Our results demonstrate high prevalence of low BMD and osteoporotic fractures in patients receiving a successful kidney transplant and indicate the need for specific intervention to prevent osteoporosis in this population.

Absorptiometry, Photon↗
PubMed2003

Discriminatory ability of quantitative ultrasound measurements is similar to dual-energy X-ray absorptiometry in a Brazilian women population with osteoporotic fracture.

The discriminating ability and relevance of clinical risk factors, quantitative ultrasound (QUS) variables, X-ray-based bone mineral density (BMD) and hip axis length (HAL) measurements to evaluate the risk of osteoporotic fracture in elderly Brazilian women were examined in this study. QUS at the calcaneus (Achilles +, Lunar), HAL and BMD measurements (DPX-L, Lunar) at several anatomical sites were performed in 275 postmenopausal Caucasian women. Patients with suspected secondary osteoporosis were excluded. One hundred twenty-two (44.4%) women had had previous osteoporotic fracture. All of the subjects were over 50 years old (range 53-93) and answered a questionnaire that included details concerning aspects of lifestyle, diet, hormonal factors and drug use. Lateral thoracic and lumbar radiographs were taken and an independent radiologist reviewed the X-rays for the presence of vertebral fractures. After adjustments for age, the most relevant risk factors to discriminate patients with osteoporotic fracture from normal non-fracture controls were Stiffness index (OR 2.8 per standard deviation; 95% confidence interval 2.3, 8.7), familial history of hip fracture (OR 2.6 per standard deviation; 95% confidence interval 2.2, 5.4), femoral neck BMD (OR 2.3 per standard deviation; 95% confidence interval 1.9, 4.2), age (OR 2.1 per standard deviation; 95% confidence interval 1.6, 2.8) and weight (OR 1.9 per standard deviation; 95% confidence interval 1.5, 2.6). HAL measurements did not associate significantly with the risk of hip fracture in this population. The ability of QUS measurements discriminate between patients with fractures from those without was similar to, if not better, than X-ray-based BMD measurements. However, a combination of QUS and BMD measurements did not significantly improve fracture discrimination compared with either technique alone. Association of clinical risk factors with QUS or BMD measurements seems, on the other hand, to increase the sensibility to identify patients at risk of osteoporotic fractures.

Absorptiometry, Photon↗
PubMed1999

[Subclinical apoplexy in pituitary tumors].

Acute pituitary apoplexy is a rare event, even in patients with pituitary macroadenomas. On the other hand, the presence of necrotic/hemorrhagic areas, especially in macroadenomas, seems to be more common than earlier reported in the CT period. After the introduction of MR in the presurgical workup of these patients, these apopleptic areas have been more easily diagnosed preoperatively. Forty consecutive patients with pituitary macroadenomas were studied with high-resolution 1.5 T T1 coronal, sagittal and axial slices over the sellar region. Special attention was paid in the detection of necrotic, cystic and hemorrhagic areas within these tumors. Ten patients had hemorrhagic/necrotic areas within their tumors, without any sign or symptom of acute apoplexy. These areas varied from small (2 mm) to very large (30 mm) ones. Seven patients had non-secreting tumors, 2 GH and 1 prolactin secreting tumors, which is the same profile of secretory pattern for the whole series (40 patients). The clinical picture included (other than that caused by endocrine secretion) slowly progressive (but not acute) visual loss (n = 8) and headache (n = 3). After surgical decompression of the surrounding structures and visual apparatus, which was facilitated by the presence of the necrotic areas, there was visual improvement in 6 patients and headache resolution in 2. The presence of asymptomatic apopletic areas in these macroadenomas and their absence in microadenomas as can be seen in the literature suggest that they are related more to the size of the tumor than to its endocrine secretion pattern. This is in agreement with a vascular insufficiency hypothesis in the pathogenesis of these lesions.

Adenoma↗
PubMed1999

[Identical twins discordant for Cushing's disease: case report[].

Cushing's disease is rare in children and its occurrence in identical twins is extremely rare. This paper reports on identical twins discordant for Cushing's disease. One of them first presented with a cushingoid phenotype by the age of 10. Her evaluation showed an increased urinary free-cortisol and serum ACTH. Her pattern in the dexametazone suppression tests was compatible with Cushing's disease. MRI disclosed a pituitary macroadenoma which was removed by the transesphenoidal approach. Immunohistochemical studies of the tumor showed the presence of ACTH-producing cells. The patient went into clinical and laboratorial remission after surgery. She re-started to grow after the disappearance of the Cushing's phenotype but she is still shorter than her healthy sister. The latter remains disease-free 4 years after her sister's diagnosis. This represents the third such case reported in the literature. Our findings suggest that acquired factors may be responsible for the genesis of Cushing's disease.

Adenoma↗
PubMedDate not supplied

[A technology with multiple applications].

Plant breeding has been a human practice for some thousands of years. However, this process of domestication has made plants more vulnerable to pests and diseases. Classic plant breeding has allowed the genetic manipulation of plants through crossings with a resulting increase in crop productivity. Recently, the recombinant DNA technology has increased the possibilities of integration of exogenous genes to the plant genome, resulting in the production of transgenic plants. Despite the great debate on this issue, such plants represent to date a promising avenue for plant breeding. There are many examples of gene transference strategies which have been successful in promoting resistance to herbicides, viruses, fungi, bacteria and insects, or in producing an increase in food quality. In addition to biotechnological applications, transgenic plants have made a significant contribution to the study of gene functioning, such as the analysis of genic expression regulation and the study of protein functions codified by distinct plant genes.

Agriculture↗