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Biomedical subjects

L del Rio

Publications and source records attributed to L del Rio.

10 recordsLinked to original sources
PubMed2001

Identifying bone-mass-related risk factors for fracture to guide bone densitometry measurements: a systematic review of the literature.

Available evidence suggests that fracture prediction with bone densitometry may improve when used on people at high risk of osteoporotic fractures. The objectives of this literature review were: (1) to identify risk factors for fracture that are associated with the development of a low bone mass for both men and women; (2) to describe and assess the relationship between these factors and the risk of fracture; and (3) to classify them according to the strength of their association with fracture incidence. Studies were identified from MEDLINE (1982-1997), HealthSTAR (1975-1997) and The Cochrane Library (1997) databases. Pre-stated inclusion criteria (original analytic studies assessing risk factors for osteoporotic fractures in men and women) and methodologic quality were assessed by two independent investigators. Information on the study design and analysis, characteristics of participants, exposure (risk factor) and outcome measures (relative risk and odds ratios for fracture incidence), control for potential confounding factors and risk estimates was extracted using a standardized protocol. Qualitative and meta-analytic techniques were used for data synthesis. As a result, risk factors were classified into three groups according to their strength of association with fracture: high risk (RR > or = 2), moderate risk (1 < RR < 2) and no risk or protective (RR < or = 1). Of approximately 80 risk factors identified from 94 cohort and 72 case-control studies, 15% were classified in the high-risk group, including low body weight, loss of weight, physical inactivity, the consumption of corticosteroids or anticonvulsants, primary hyperparathyroidism, diabetes mellitus type 1, anorexia nervosa, gastrectomy, pernicious anemia, and aging (> 70-80 years). Eighteen percent and 8% of risk factors were classified in the moderate and no risk group respectively, whereas 60% showed either a lack of scientific evidence confirming their association with fracture or contradictory results. An efficient strategy for bone densitometry provision may thus be its selective use in those individuals who present with several strong or moderate risk factors for fracture related to bone mass loss.

Adrenal Cortex Hormones↗
PubMed1995

Vertebral fractures and osteopenia in chronic alcoholic patients.

To assess whether vertebral fractures are associated with osteopenia in chronic alcoholic patients, a transversal study was carried out in 76 chronic alcoholic males and 62 age-matched healthy males. Lumbar bone mineral density (BMD) by dual photon absorptiometry and spinal chest X-ray films were done in all patients. Twenty-seven patients (36%) had vertebral fractures, but only 5 of them had a BMD below the fracture threshold. Twenty-two patients (29%) had osteoporosis by densitometric criteria. There were no significant differences in lumbar BMD between alcoholic patients with and without vertebral fractures (1.11 +/- 0.2 versus 1.13 +/- 0.2, P = ns). Previous trauma was recorded in 24 of the 27 patients with vertebral fractures and in 28 of the 49 patients without vertebral fractures (P < 0.001). Moreover, patients with vertebral fractures had more peripheral fractures than patients without vertebral fractures (81% versus 49%, P = 0.01). Only one patient was aware of a previous episode of traumatic vertebral fracture. In conclusion, chronic alcoholics frequently have traumas and vertebral fractures, the latter despite having a lumbar BMD above the fracture threshold, suggesting a frequent but unrecognized association between both processes. These results suggest that both spine films and BMD measurements should be obtained for diagnosis of osteoporosis in alcoholic patients.

Absorptiometry, Photon↗
PubMed1994

Bone mineral density of the lumbar spine in white Mediterranean Spanish children and adolescents: changes related to age, sex, and puberty.

Bone mineral content was measured by dual-energy x-ray absorptiometry in the lumbar spine at the L2-L4 level with a Lunar DPX densitometer model in 471 healthy white Mediterranean Spanish children and adolescents (256 boys and 215 girls) randomly selected from the urban area of Barcelona. Ages ranged from 3 mo to 21 y. Weight, height, and pubertal development were in the normal age distribution. Bone mineral content values were corrected by the vertebral surface area scanned and expressed as bone mineral density (BMD) values. BMD increased progressively from infancy to adulthood, and values were similar in both sexes, with the only differences related to the earlier onset of puberty in girls. A statistically significant correlation (p < 0.001) was found between BMD values and age, height, and weight. BMD values increased annually, but the periods of higher increase were observed during the first 3 y of life and late puberty. A significant (p < 0.001) increase in BMD was observed between Tanner pubertal stages III and IV and between Tanner stage IV and adult values. Lumbar BMD values peaked in a similar way to growth height velocity during pubertal development. However, the BMD peak seemed to occur somewhat later than height velocity peak, particularly in girls. In conclusion, we report normative data for BMD values at the lumbar level in our normally growing pediatric population and show that the first 3 y of life and adolescence are critical periods for bone mineralization. These data provide a tool for the investigation and follow-up of pediatric populations at risk for low bone mineralization.

Absorptiometry, Photon↗
PubMed1994

Comparison of subcutaneous unfractionated heparin with a low molecular weight heparin (Fragmin) in patients with venous thromboembolism and contraindications to coumarin.

Intravenous heparin followed by oral anticoagulant therapy (e. g. with coumarin) is still the most widely used treatment for deep venous thromboembolism. Self-administered subcutaneous injections of heparin have been thought of as a promising alternative to coumarin, but the high doses required for ongoing prophylaxis have raised concerns about the possible development of bone disease. Certainly, long-term heparin therapy has been reported to cause osteoporosis in both laboratory animals and humans. This study aimed to compare the efficacy and safety of unfractionated (UF) heparin with that of a low molecular weight heparin (Fragmin, Kabi Pharmacia) in the prevention of recurrent deep venous thrombosis (DVT) and pulmonary embolism (PE) in a consecutive series of patients with contraindications to coumarin therapy. The patients comprised 40 men and 40 women, aged between 19 and 92 years (mean age, 68 years). They had all previously been diagnosed as having acute DVT and had been treated with conventional doses of heparin while in hospital. All patients had at least one of the following conditions: recent blood loss (either spontaneous or during admission while receiving heparin therapy); active gastroduodenal ulcer disease; psychological or physical inability or unwillingness to understand and accept the need for regular laboratory monitoring during coumarin treatment; chronic alcoholism; dementia; pregnancy; recent neurosurgery, and pericardial effusion; or were over 80 years of age. They were randomly allocated to receive either UF heparin, 10,000 IU s.c. b.d., or Fragmin, 5000 IU anti-Factor Xa s.c. b.d., for a period of 3-6 months.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Sodium fluoride prevents bone loss in primary biliary cirrhosis.

Low-bone-turnover osteoporosis is a common complication of primary biliary cirrhosis (PBC). Since sodium fluoride stimulates bone formation we assessed the effect of this drug on bone mass in a 2-year, prospective, double-blind trial including 22 women with PBC who were randomly assigned to receive sodium fluoride (50 mg/day) or placebo. All received calcium supplements and low doses of vitamin D. Bone mineral density of the lumbar spine was measured by dual-photon absorptiometry initially and every 6 months. Vertebral fractures were evaluated in thoracic and lumbar spine initially, and after 1 and 2 years. Seven patients in the fluoride group and eight in the placebo group completed the trial. In the fluoride group, bone mineral density did not change after 2 years (initial 1.05 +/- 0.07, final 1.07 +/- 0.06 g/cm2; p = n.s.). In the placebo group, however, bone mineral density decreased significantly (initial 1.00 +/- 0.07, final 0.93 +/- 0.06 g/cm2; p = 0.03). Moreover, in the fluoride group bone mineral density increased by 2.9 +/- 3.6%, and in the placebo group decreased by 6.6 +/- 2.6% (p = 0.04). None of the patients developed new vertebral or non-vertebral fractures. Treatment with sodium fluoride did not impair liver function or cholestasis in PBC. These results indicate that sodium fluoride prevents bone loss in PBC and therefore might be considered as a possible therapeutic agent for osteoporosis associated with this liver disease. Since a small number of patients completed the trial, further studies are required.

Absorptiometry, Photon↗
PubMed1983

Evolution of the influenza virus neuraminidase gene during drift of the N2 subtype.

The complete genetic information for the neuraminidase (NA) gene of influenza virus A/Bangkok/1/79 has been cloned by in vitro synthesis of dsDNA, insertion into pBR322 plasmid, and transformation of Escherichia coli. The nucleotide sequence of the NA gene has been determined by the Maxam and Gilbert method. It is 1466 nucleotides long and contains a single open reading frame with a coding capacity for 469 amino acids. When compared to the NA genes of the N2 strains A/Victoria/3/75, A/Udorn/72, A/NT/60/68, and A/RI/5-/57, 90% of the nucleotide positions and 87% of the amino acid positions remained invariant. Forty-two nucleotide changes and 14 amino acid changes accumulated in the period 1975-1979, but the general structure of the protein appeared to remain constant.

Amino Acid Sequence↗