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Biomedical subjects

A Díez

Publications and source records attributed to A Díez.

At least 19 recordsLinked to original sources
PubMed2000

[Treatment of osteoporosis with calcium and vitamin D. Systematic review].

BACKGROUND: Systematic review of the efficacy of calcium and vitamin D for the treatment of osteoporosis. MATERIAL AND METHOD: Review of the database MEDLINE between 1996 and may 1998, by the key words: osteoporosis, calcium, vitamin D (and related terms) and randomized clinical trial. Review of the electronic versions of Best Evidence, The Cochrane Library, congress abstracts and references from two main textbooks. Ascending review of the literature. All the reviews were performed independently by two of the authors. Design parameters and main results of the primary publications of the identified trials were tabulated. Two independent observers carried out methodological scoring of the studies. Results were tabulated and a judgement made for the results. RESULTS: Eleven studies on calcium, 8 of vitamin D and 12 about calcitriol and other hormone derivatives were included. Studies with calcium were mainly performed on non-clinical populations and in three anti-fracture efficacy was analyzed. Results were positive in population with low baseline intake and substantial supplementation. Trials on vitamin D were done in non-clinical and on institutionalized populations. Trials with calcitriol were developed mainly in osteoporotic fracture populations and reached poorer methodological validity scores. Heterogeneity of the studies precluded a meta-analysis of the different treatments. Studies on calcium showed clinical efficacy in a more consistent way. Inter-observer score was good (kappa = 0.81) and there were no significant correlations between sample size and effect in the different studies. CONCLUSIONS: Calcium treatment is efficacious in populations with low intake receiving substantial supplementation. Vitamin D is efficacious associated with calcium mainly in deficient populations. Efficacy of calcitriol and other derivatives is more controversial.

Calcitriol↗
PubMed1999

In vitro synthesis of type I collagen: quantification of carboxyterminal propeptide of procollagen type I versus tritiated proline incorporation.

Radioimmunoassay of the carboxyterminal propeptide of human type I procollagen has been recently introduced to measure in vitro synthesis of type I collagen by osteoblasts and fibroblasts. However, it has not been assessed whether the equivalent results are obtained with this new assay and with tritiated proline incorporation to collagen protein. To this purpose, both methods were used to quantify synthesis of type I collagen in normal human osteoblast cultures to which fetal calf serum and human serum were added in order to stimulate protein synthesis. A positive correlation in the results obtained by both methods was obtained (r = 0.95, P = 0.0001). Given the technical advantages of detection of levels to carboxyterminal propeptide of type I procollagen, we consider that this is the technique of choice for the quantification of in vitro synthesis of type I collagen by normal human osteoblasts.

Aged↗
PubMed1999

[Adherence to very active antiretroviral treatment: impact of individualized assessment].

BACKGROUND: To determine if the intervention of individual advice improves adherence and effectiveness to highly active antiretroviral therapy. METHODS: Randomized open trial. Patients treated with zidovudine + lamivudine + indinavir were assigned (2/1) to conventional care or individual advise. Individual advise consists in adaptation to treatment to patient style of live and detailed information of therapy. Adherence were estimated with structured interview and pillo counts and were considered correct when more than 90% of prescribed drugs were taken. RESULTS: Patients 170, conventional care: 110 and IA: 60. FOLLOW-UP: 24 weeks. Baseline characteristics were similar in both groups. Correct adherence were estimated in 52.7% of conventional care and in 76.7% of individual advise (p = 0.002, relative risk: 1.45; CI 95%: 1.16-1.82). Undetectable viral load (NASBA < 50 copies/ml) in 54.5% of conventional care and in 65% of individual advise (p = 0.18, relative risk: 1.19; CI 95%: 0.93-1.53). Reduction of viral load in the conventional care group 1.02 +/- 0.5 log10/ml, and in the individual advise group 1.98 +/- 0.7 log10/ml. CONCLUSION: The individual advice improve adherence with a tendency to improve effectiveness of highly active antiretroviral therapy.

Adult↗
PubMed1999

DNA image cytometry. An alternative method in osteoblast proliferation assays.

OBJECTIVE: To assess whether DNA image cytometry can be used as an alternative method to tritiated thymidine uptake quantification in osteoblast proliferation assays. STUD DESIGN: Proliferation of normal human osteoblasts incubated with normal human serum at 0%, 2.5%, 5%, 10%, 20% and 40% was quantified by tritiated thymidine uptake quantification and DNA image cytometry. RESULTS: Tritiated thymidine uptake quantification showed that normal human serum stimulated the proliferation of normal human osteoblasts and that the degree of stimulation was directly related to the concentration of serum in the culture medium. Similar results were obtained when the DNA image cytometry assay was used. A highly significant linear relationship between the ranks of both methods was found (Spearman's r = 1.00, P = .0253). CONCLUSION: DNA image cytometry may be a valuable alternative when the use of radioactive material is not desired and/or subsequent morphologic or immunocytochemical characterization of cells under study is required.

Aged↗
PubMed1998

Relation between exploratory activity and immune function in aged mice: a preliminary study.

Previous studies show that fast exploration of a T-shaped maze by mature mice may predict an above average longevity. Since the nervous and the immune systems work in a coordinated fashion, and it seems that these two homeostatic systems both influence organismic aging and suffer a senescent decline, we have performed a comparative study of the above behavioral parameter and different functions of three representative immune cells: lymphocytes, macrophages and natural killer (NK) cells obtained from old (76 +/- 1 weeks of age) female OF1-Swiss mice. At 70 weeks of age the mice were divided into a 'fast' and a 'slow' group, containing 100 and 0%, respectively, of animals able to explore the 50 cm-long first arm of the maze in 20 s or less. At 76 +/- 1 weeks of age the animals were sacrificed, the peritoneal cell suspensions were obtained and the immune organs (axillary nodes, spleen and thymus) were isolated. The following leukocyte functions were studied in peritoneal macrophages: adherence to substrate, mobility (spontaneous and chemotaxis), ingestion of particles and superoxide anion production whereas mobility, lymphoproliferative response to the mitogen Con A and NK activity were studied in the immune-organ leukocyte suspensions. The results show that the aged fast mice have better immune functions than the aged slow mice.

Aging↗
PubMed1998

[Calcitonin prescriptions: an estimate of the expenditure due to inadequate prescription].

BACKGROUND: The use of calcitonin is very common in patients diagnosed with osteoporosis. The objective of this study was to determine the percentage of adequate prescriptions of calcitonin for patients with osteoporosis and to estimate the costs due to inadequate prescription. PATIENTS AND METHODS: Observational study. Four pharmacies in Osona County (Barcelona) were randomly selected. During two time periods, July-September and November-December of 1994, all women filling prescriptions for calcitonin in any of the eight pharmacies were invited to participate in the study. Adequate and inadequate prescription of calcitonin was determined based on the patient's clinical record. Justifiable and non-justifiable prescriptions were then determined after implementing a protocol and reviewing X-rays of the spine. RESULTS: Forty-eight women agreed to participate (participation rate: 68%). In the first analysis, 58.3% (95% CI: 43-72) of prescriptions were determined to be inadequate whereas in the second analysis 29.2% (95% CI: 17-44) were considered non-justifiable. Chronic back pain was associated with non-justifiable prescription of calcitonin (odds ratio: 5.2; 95% CI: 1.3-33.4). In the best of situations, the excess in annual spending due to inadequate prescription was estimated at 13 million pesetas for Osona County, 1,300 million for Catalonia, and 4,300 million for Spain. CONCLUSIONS: Between one-third and one-half of patients prescribed calcitonin in the study area apparently do not need it. Many cases of chronic back pain are being treated as osteoporosis without being properly studied. The costs derived from this incorrect practice are important. This study highlights the need for better practices in the diagnosis of osteoporosis.

Adult↗
PubMed1998

[Screening for bone disease risk with clinical factors in women after physiologic menopause].

BACKGROUND: Densitometric screening for osteoporosis in postmenopausal women has not been demonstrated cost-effective. We have tried to identify clinical factors for screening previous to densitometry avoiding unnecessary explorations. PATIENTS AND METHODS SETTING: outpatient clinics of a menopausal unit in a 450-bed general hospital. Cross-sectional study, in two steps, of two groups of 140 and 284 women attending for physiological menopause. A clinical questionnaire, physical data and lumbar densitometry (Hologic QDR 1000) were obtained classifying the cases as "normal" or "low bone mass" (osteopenia or osteoporosis) according with the WHO criteria. In the first group a logistic regression analysis was done to identify predictive factors for abnormal densitometry, then validated in the second group. Sensitivity, specificity, predictive values (PV) and classification ability of clinical factors were analyzed. RESULTS: Four factors were independent predictors of abnormal densitometry: age > 51 (odds ratio [OR] = 6.64; 95% CI, 2.36-18.7); body weight < 70 kg (OR = 4.32; 95% CI, 1.71-10.09); years of fertility < 32 (OR = 3.77; 95% CI, 1.36-10.04), and number of live births > 2 (OR = 3.47; 95% CI, 1.27-9.53). Presence of one factor offers: sensitivity 91.9%; specificity 15%; positive PV 66.6%, and negative PV 50%, whereas the presence of two factors offers: sensitivity 62.7%; specificity 70%; positive PV 79.9%, and negative PV 50.3%. Clinical screening allows, when two factors are present, to avoid a 35.5% of densitometries and the false-negative cases represent 18%. CONCLUSIONS: Detection of bone-risk clinical factors (abnormal densitometry) yields a screening, previous to densitometry, that avoids at least one third of explorations in women with physiological menopause, improving the efficiency of the test.

Cross-Sectional Studies↗
PubMed1998

Increase with age of serum lipid peroxides: implications for the prevention of atherosclerosis.

There is considerable support for the concept that oxygen free radicals and related lipid peroxides play a key role in the pathogenesis of normal senescence and of age-related chronic degenerative diseases, including atherosclerosis. This has led to a great deal of interest regarding peroxidized LDL, which seems to be more atherogenic than LDL. In contrast, the relationship of total serum or plasma lipid peroxides (which also have a marked atherogenic action) with both aging and atherogenesis are not well understood. In view of the above, we have determined the level of serum lipid peroxide (expressed as thiobarbituric acid reactive substances) in a sample of 100 healthy men and women ranging in age from 20 to 70 years. Our data show that there is an age related increase in the concentration of lipid peroxide, with men showing higher or about equal values than women until about 60 years, after which age women show the higher values. Our data also suggest that in certain men and women, aging is linked to a decline in the competence of the oxyradical-detoxifying mechanisms, which results in increased serum lipid peroxidation. Further research is needed to find out if lowering the serum peroxide levels of aging subjects by diet supplementation with antioxidants will decrease that risk. An adequate intake of antioxidants seems especially indicated in post-menopausal women because of their apparent greater sensitivity to age related oxygen stress.

Adult↗
PubMed1998

Effect of alendronate on cultured normal human osteoblasts.

Alendronate is an aminobisphosphonate with a potent anti-reabsorptive action that does not appear to interfere with bone mineralization, and is even able to increase bone mineral density in osteoporotic postmenopausal women through a still not fully understood mechanism. This study was conducted to assess the direct effect of alendronate on diverse aspects of normal human osteoblast physiology. For that purpose, the in vitro effect of a wide range of concentrations [from 10(-1) to 10(-12) mol/L] of alendronate on cell viability, proliferation, collagen synthesis, and the mineral-depositing capacity of normal human osteoblasts was tested. Alendronate effects were examined at 48 and 96 h of culture in the presence or absence of fetal calf serum. In vitro alendronate affected osteoblast viability at concentrations equal to or higher than 10(-4) mol/L. At concentrations equal to or higher than 10(-3) mol/L, no viable cells were observed in cultures. In vitro alendronate at concentrations between 10(-5) and 10(-12) mol/L did not have any effect on the proliferative capacity of normal human osteoblasts determined by two different techniques: (1) tritiated thymidine incorporation to DNA and (2) cell counting. Collagen synthesis by normal human osteoblasts showed a tendency to decrease following incubation with alendronate supplemented with fetal calf serum. This decrease was only statistically significant after 96 h of culture; however, a dose-response effect could not be documented. Finally, no effect of alendronate was observed on calcium deposition in vitro by normal human osteoblasts at concentrations equal to or lower than 10(-5) mol/L. In conclusion, the present study shows that alendronate in vitro does not affect viability, proliferation, and mineral deposit capacity of normal human osteoblasts at the concentration at which it inhibits by 50% the resorptive capacity of osteoclasts that for this drug has been reported as 2 x 10(-9) mol/L.

Adult↗
PubMed1998

Vitamin D treatment in myelodysplastic syndromes.

Myelodysplastic syndromes (MDS) are a group of clonal disturbances with defective cellular differentiation. Vitamin D3 (VD) analogues can act on the differentiation and maturity of different cell lines. We studied the effects of VD on a series of patients with MDS in an open-design trial. Nineteen patients, 12 men and seven women, with MDS were included. Patients were 74.8 +/- 5.6 years (mean +/- SD), seven had refractory anaemia with ringed sideroblasts, five had refractory anaemia, one had refractory anaemia with excess of blasts and six had chronic myelomonocytic leukaemia. All the patients were in a low to intermediate risk group. Mean follow-up period was 26.21 months, range 9-75. Responders were defined as follows: granulocyte or platelet count increase by 50%, or haemoglobin increase of 1.5 g/dl or transfusion needs decrease by 50%. The first five patients received 266 microg of calcifediol three times a week and the other 14 received calcitriol (0.25-0.75 microg/d). Response was observed in 11 patients. In the calcifediol-treated group, one case responded, three were nonresponders, and one showed progression. In the calcitriol group, 10 were responders (two with major response), and four were non-responders. No correlation was observed between baseline levels of vitamin D metabolites and the presence of response. No hypercalcaemia was observed. Treatment with vitamin D3 metabolites could induce a long-standing response of the haematological disturbance in some low-intermediate risk MDS patients without inducing hypercalcaemia.

Aged↗
PubMed1997

[Acceptance of, compliance with and tolerance to antiretroviral treatment in patients with human immunodeficiency virus infection].

BACKGROUND: The objective of the study is to assess the acceptance, compliance and side effects of antiretroviral therapy in relation to age, gender, risk group, HIV infection stage and type of treatment. METHODS: This is a cohort-observational study. Inclusion criteria were: consecutive non-selected IIV patients in which antiretroviral treatment was indicated on medical grounds. The study was carried out from February 1990 to February 1996. We measured: a) poor compliance, when suspicion (by medical history, analytical data and administered drug control by the hospital pharmacy) more than a 25% of prescribed treatment was not taken; b) adverse events that obliged to discontinued the drug; and c) long-term therapy, when treatment acceptance and compliance and regular follow-up was stated. Statistics methods: Ji-square and Student's t- test. RESULTS: 567 patients were included, with a median follow up of 609 days. Male 413, female 154. Mean age: 32.9 years. Average CD4+ cells: 0.260 x 10(9)/L. There was a history of intravenous drug use (IDU) in 60.4% of cases and CDC classification group C (1993) 34.2%. Antiretroviral treatment was refused by 16.6% of patients, more frequently IDU patients (21.3%, p < 0.0001). There was a drop-out rate of 17.3%, with no differences among different groups. Poor compliance was found in 23% of cases, more frequently in IDU and group-C patients. Adverse events were observed in 22.6% of cases, more frequently in female (33.8%, p < 0.0004) and group C patients (28.6%, p < 0.04). The treatments used (AZT monotherapy, DDI monotherapy, AZT DDI and AZT + DDC) had no influence on compliance or follow-up. Long-term follow-up and compliance was achieved in 47.6% of patients, with a lesser degree in IDU (42.4%, p < 0.002) and group C patients (39.7%, p < 0.006). CONCLUSIONS: HIV-infected patients treated with antiretroviral agents, not enrolled in clinical trials, had similar rates of compliance that patients with other chronic diseases. Treatment refusal and poor compliance were more frequent in IDU patients, while adverse events were more frequent in patients with more advanced HIV infection stage.

Adult↗