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Biomedical subjects

J R García-Talavera

Publications and source records attributed to J R García-Talavera.

8 recordsLinked to original sources
PubMed1998

Low bone density with normal bone turnover in ovariectomized and streptozotocin-induced diabetic rats.

Diabetes and estrogen deficit are known causes of osteopenia, diabetes being associated with a low bone turnover and estrogen deficit with a high bone turnover. In the present work, we studied the effect of combined ovariectomy and diabetes on bone mineral content (BMC) and bone mineral density (BMD) and several bone markers in the rat. Four groups of rats were studied: control (C), ovariectomized (O), diabetic (D), and ovariectomized and diabetic (DO). Twelve weeks after starting the experiments, BMC and BMD of the first six lumbar vertebrae were measured; a bone formation marker (BGP) and a bone resorption marker (free collagen cross-links, PYD) were also analyzed. Diabetic rats showed diminished gain in bone mass, BMC (D: 0.417 +/- 0.028 g, DO: 0.422 +/- 0.020 g) and BMDs (D: 0.171 +/- 0.006 g/cm2, DO: 0.174 +/- 0.006 g/cm2) both being significantly (P < 0.001) lower than those of control (C: BMC 0.727 +/- 0.024 g and BMD 0.258 +/- 0.004 g/cm2) and ovariectomized (O: BMC 0.640 +/- 0.044 g and BMD 0.240 +/- 0.009 g/cm2) groups. Moreover, the BMC and BMD of the C group were significantly (P < 0.05) higher than that of the O group. BGP and PYD levels were significantly (P < 0.01) higher in the O group (BGP: 138.2 +/- 16.8 ng/ml, PYD: 270.2 +/- 17.8 nM/mM) than those found in the control rats (BGP: 44.7 +/- 4.8 ng/ml, PYD: 165.6 +/- 12.5 nM/mM); the D group showed significantly (P < 0.01) lower values (BGP: 27.4 +/- 14.6 ng/ml, PYD: 55.0 +/- 7.4 nM/mM) than those of the control group. The DO group showed similar levels (BGP: 43.4 +/- 5.1 ng/ml, PYD: 146.7 +/- 14.6 nM/mM) to those found in the C group. Although bone marker levels in the O and D groups were in accordance with those expected in these situations, in the DO group the corresponding levels are apparently "normal." Also, the decrease of gain in bone mass observed after combining estrogen deficit and diabetes (DO group) did not seem to be more marked than that caused by diabetes alone.

Amino Acids↗
PubMed1995

Heterogeneous decrease of bone mineral density in the vertebral column of ovariectomized rats.

The long-term effect of ovariectomy on the loss of bone mineral density (BMD) was evaluated in rats with and without estrogen treatment; BMD was studied in the lumbar and caudal vertebrae, measured by DXA, to find how the losses of BMD occur in the axial skeleton. Seventy female Wistar rats of 3 months of age were divided into four groups as follows: group 1: control animals; group 2: ovariectomized animals; group 3: ovariectomized animals undergoing treatment with estrogen (0.25 mg/kg per week of 17-beta estradiol); group 4: ovariectomized rats undergoing estrogen treatment only during the last 3 months of the experimental period. No significant differences were found among the groups in regard to the BMD values of the caudal vertebrae at either 3 or 6 months. Likewise, in the lumbar vertebrae there were no significant differences among the groups after 3 months. However, at 6 months, a decrease in the BMDs of the ovariectomized animals with respect to the remaining groups was found: 226 +/- 11 mg/cm2 in the ovariectomized group; 262 +/- 14 mg/cm2 in the controls; 255 +/- 4 mg/cm2 in the rats receiving estrogen treatment for 6 months; and 259 +/- 5 mg/cm2 in the animals receiving estrogen for 3 months. The study also reveals the absence of differences in the bone mineral density between the ovariectomized and control rats when the former received estrogen treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Absorptiometry, Photon↗
PubMed1990

Influence of sex, age, and menopause in serum osteocalcin (BGP) levels.

Osteocalcin (bone Gla protein) is a promising marker of bone turnover useful in the diagnosis and follow-up of high turnover osteoporosis. Conflicting results have been reported about its physiological variations according to sex, age, and menopause. Several, but not all, authors have found increased levels in males, with aging, and after menopause. We measured serum osteocalcin in 126 healthy subjects, 57 males and 69 females, aged between 45 and 88 years. Osteocalcin was higher (P less than 0.01) in males (6.24 +/- 0.36) than in females (4.32 +/- 0.34). This sexual difference was significant, too, in subjects younger and older than 60 years. Osteocalcin increased with age, linearly in males (P less than 0.05), and exponentially in females (P less than 0.05). Although there was a difference in age (P less than 0.05), no difference in osteocalcin levels between premenopausal women and women in their first two postmenopausal years was detected, while osteocalcin was significantly increased in women more than two years into menopause. We conclude that osteocalcin in healthy subjects is higher in males than in females and increases with age after 45 years in both sexes. Osteocalcin levels increase in women more than two years beyond menopause, but not only as an effect on aging.

Age Factors↗
PubMed1987

Assessment of multimeric structure and ristocetin-induced binding to platelets of von Willebrand factor present in cryoprecipitate and different factor VIII concentrates.

The multimeric structure of von Willebrand factor (vWF) and its ristocetin-induced binding to platelets, using a simple and very sensitive radiomonoclonal antibody-labeled vWF method, was compared in normal plasma, single-donor cryoprecipitate (CP) and five different antihemophilic factor (AHF) concentrates. All the AHF showed a lack of larger vWF multimers, an abnormal 'triplet' pattern, and much lower vWF binding to platelets than that of plasma or CP, vWF being the lowest for those with a lesser proportion of larger vWF multimers. These results suggest that the combination of vWF multimeric analysis and the radiomonoclonal-labeled vWF method may be very useful in the assessment of AHF preparations.

Blood Platelets↗
PubMed1982

[Effect of ionizing radiations on certain parameters of the immune status of cancer patients].

The authors study the action of ionizing radiations upon some aspects of the humoral and cellular immune responses in cancer patients. Both humoral and cellular responses are altered in patients having malignant neoplasms; the therapeutic irradiation diminishes the phagocytic activity of monocytes and granulocytes, the number of lymphocytes, the formation of E rosettes, and the lymphocytes blastic transformation, and produces some changes in immunoglobulins. However, the irradiation-induced changes are such that radiation therapy does not conditionate negatively the neoplastic process evolution.

Antibodies, Neoplasm↗
PubMed1979

[Endocrine studies in cryptorchidism (author's transl)].

The endocrinological study of the cryptorchid testicle was carried out using a HCG and LH-RH tests to stimulate the hypophysis. Stimulation with LH-RH demonstrated a low hypophysis reserve in some cases which made suspect the presence of a hypo-stimulated testicle. One is led to believe in the heterogeneous nature of the endocrinological response.

Chorionic Gonadotropin↗