Differential effects of 17beta-estradiol and raloxifene on bone and lipid metabolism in rats with chronic kidney disease and estrogen insufficiency.

OBJECTIVE: The aim of this study was to evaluate the effect of 17beta-estradiol, raloxifene, and 1-alpha,25-dihydroxycholecalciferol or calcitriol on bone and lipid metabolism in chronic kidney disease and estrogen insufficiency. METHODS: Six-month-old female Sprague-Dawley rats (n = 48) were ovariectomized and nephrectomized (seven eighths). One week after surgery, the rats were divided into six groups and treated with (1) placebo, (2) 17beta-estradiol 10 microg kg day, (3) raloxifene 1 mg kg day, (4) calcitriol 10 ng kg day, (5) 17beta-estradiol + calcitriol, and (6) raloxifene + calcitriol. A group of untreated animals with chronic kidney disease and normal ovarian function was used as a control group (n = 5). The rats were killed after 8 weeks of treatment. Blood samples were drawn for serum analyses; the right tibia was removed to perform histomorphometric analyses, uteri were used as tissue markers of estrogen replacement, and paraffin-embedded sections of the uterus and the fourth breast were used for histopathologic evaluation. RESULTS: Raloxifene, alone or combined with calcitriol, and 17beta-estradiol combined with calcitriol significantly diminished total cholesterol level compared with placebo. Qualitative histological and histomorphometric analyses showed that both the single treatments and their combinations were able to increase the trabecular connectivity compared with placebo. The less beneficial results were obtained with 17beta-estradiol alone, whereas the more beneficial results were obtained with the combined treatments, particularly with raloxifene and calcitriol. CONCLUSIONS: In summary, this experimental study demonstrates the advantages of replacing both hormonal deficiencies together. The combination of calcitriol and raloxifene, a selective estrogen receptor modulator, showed a better lipid, uterus, and bone profile.

Long-term response of cultured rat parathyroid glands to calcium and calcitriol: the effect of cryopreservation.

AIM: This study aimed to investigate the longest period in which parathyroid glands cultured in vitro maintained their viability and functionality in order to study the response of the glands to factors that exert their main action in the long term (1-7 days). METHODS: Rat parathyroid glands from 104 Wistar rats were used. Cell viability was measured by flow cytometry for 7 days. Parathyroid tissue functionality was determined by parathyroid hormone (PTH) secretion in basal conditions and in the response of the glands to calcium and calcitriol. Calcium sensing receptor (CaR) synthesis was determined measuring protein levels by immunohistochemistry. Parathyroid glands were cryopreserved to study them in the same way as fresh tissue. RESULTS: Intact parathyroid glands maintained their cell viability >80% until the 6th day in culture, while the functional capacity was limited to 4 days: PTH release was stable for 4 days, whilst from the 5th day onwards, PTH secretion reduced to undetectable levels. Parathyroid glands responded accurately when calcium was reduced in the culture medium; a mean increase >50% in PTH secretion was observed. No differences were observed in CaR levels before and after the culture period. PTH synthesis and secretion inhibition was observed when the parathyroid glands were cultured with calcitriol; this inhibition achieved 90% after 4 days in culture. Cryopreserved parathyroid glands maintained their viability, but partially lost their functionality, as they were unable to respond to calcium. CONCLUSIONS: Intact parathyroid glands cultured in vitro maintained their functionality and their capacity to respond to their effectors for longer periods than in previously developed studies. It seems that part of this capacity is lost after cryopreservation. Nevertheless, this long-term culture model can be useful to study the response of the parathyroid glands.

Effect of VDR gene polymorphisms on osteocalcin secretion in calcitriol-stimulated human osteoblasts.

BACKGROUND: The impact of vitamin D receptor (VDR) gene polymorphisms in bone metabolism remains controversial. Some authors have found a beneficial effect of some VDR gene polymorphisms, while others found no differences, or even a lower bone mass in subjects with the same type of polymorphisms. The aim of this study was to assess if the VDR gene polymorphisms could have an effect on the calcitriol-stimulated osteocalcin in human osteoblasts. METHODS: Osteoblasts were obtained from human femoral necks replaced because of osteoarthritis. Bones were cut into pieces of 1 to 2 mm and placed in a nylon mesh. After the migration of osteoblasts, the pieces were collected and cultured with different concentrations of calcitriol (10(-8), 10(-9), and 10(-1)0 mol/L). After 48 hours of incubation with calcitriol, the osteocalcin secreted into the medium (corrected by either total proteins or total DNA content) was measured. The DNA was extracted from the osteoblasts, amplified by polymerase chain reaction (PCR), and analyzed for target sequences sites of the BsmI, ApaI, TaqI, and FokI restriction enzymes. RESULTS: The response observed in osteocalcin secretion in the bb or TT genotypes doubled the response observed in the BB or tt genotypes (calcitriol 10(-8) and 10(-9) mol/L). A slight trend was also observed with the aa genotype. Men showed higher levels of osteocalcin secretion than women. Age did not show any influence in osteocalcin secretion. CONCLUSION: VDR alleles and gender demonstrated an effect on the osteocalcin secretion. BB or tt genotypes, and also the "A" allele, showed the lowest calcitriol-stimulated osteocalcin secretion.

Esquizofrenia: prueba de aglutinación / Schizophrenia: agglutination test

La presencia de antigeno del virus herpes simplex hominis tipo I neuronas del sistema límbico de pacientes esquizofrénicos fallecidos, fetos de madres esquizofrénicas y en embriones de pollo experimentalmente inoculados con líquido céfalo-raquideo, nos hizo considerar el desarrollo de una prueba biológica en la esquizofrénia a partir de marcadores periféricos: sangre y líquido céfalo-raquídeo. El hallazgo de una prueba de precipitación en el curso de estas investigaciones aumenta el valor de los resultados obtenidos en las pruebas anteriores con fines diagnósticos, pronósticos, médico legal,epidemiológico, para la investigación y en el tratamiento de los pacientes con medicamentos antivirales, como son el uso de interferón y acyclovir por períodos prolongados de tiempo. La prueba puede ser realizada en la investigación del laboratorio clínico en centros asistenciales, al menos en su fase inicial. Se basa en dos aspectos fundamentales: poner en contacto directo la presencia de posibles antigenos que pasan del sistema nervioso central al líquido céfalo-raquídeo con el sistema inmunológico de la sangre periférica del propio paciente, salvando de esta forma la barrera hematoencefálica y teniendo en cuenta además la reacción inmunológicas de tipo celular que se observa en las enfermedades virales lentas del sistema nervioso central. El estudio complementario con microscopía óptica, inmunofluorescencia y microscopia electrónica permite confirmar los hallazgos hechos en la relación macroscópica de aglutinación(AU)

Esquizofrenia: prueba de aglutinación / Schizophrenia: agglutination test

La presencia de antigeno del virus herpes simplex hominis tipo I neuronas del sistema límbico de pacientes esquizofrénicos fallecidos, fetos de madres esquizofrénicas y en embriones de pollo experimentalmente inoculados con líquido céfalo-raquideo, nos hizo considerar el desarrollo de una prueba biológica en la esquizofrénia a partir de marcadores periféricos: sangre y líquido céfalo-raquídeo. El hallazgo de una prueba de precipitación en el curso de estas investigaciones aumenta el valor de los resultados obtenidos en las pruebas anteriores con fines diagnósticos, pronósticos, médico legal,epidemiológico, para la investigación y en el tratamiento de los pacientes con medicamentos antivirales, como son el uso de interferón y acyclovir por períodos prolongados de tiempo. La prueba puede ser realizada en la investigación del laboratorio clínico en centros asistenciales, al menos en su fase inicial. Se basa en dos aspectos fundamentales: poner en contacto directo la presencia de posibles antigenos que pasan del sistema nervioso central al líquido céfalo-raquídeo con el sistema inmunológico de la sangre periférica del propio paciente, salvando de esta forma la barrera hematoencefálica y teniendo en cuenta además la reacción inmunológicas de tipo celular que se observa en las enfermedades virales lentas del sistema nervioso central. El estudio complementario con microscopía óptica, inmunofluorescencia y microscopia electrónica permite confirmar los hallazgos hechos en la relación macroscópica de aglutinación