Establishment of HEK293 cell lines stably expressing human parathyroid hormone receptors / 南方医科大学学报

<p><b>OBJECTIVE</b>To establish HEK293 cell lines with stable expression of human parathyroid hormone (PTH) receptors.</p><p><b>METHODS</b>The purified gene fragments of PTH-related peptide receptor (PTHR) and its mutant form (DSEL) were cloned separately into pcDNA3.1(+) vector after digestion with EcoR I and Not I, and the resulted pcDNA3.1(+)-PTHR and pcDNA3.1(+)-DSEL plasmids were verified by restriction enzyme digestion and DNA sequencing. HEK293 cells were transfected with these plasmids and the expression of PTHR and DSEL in the cells were examined by RT-PCR and ELSIA.</p><p><b>RESULTS</b>Sequencing and restriction enzyme digestion analysis showed that PTHR and DSEL cDNAs were correctly cloned into pcDNA3.1(+)vector. After a 48-h transfection of HEK293 cells with the recombinant plasmids and G418 selection, the positive cell clones stably expressing the constructs were obtained, which showed expressions of PTHR and DSEL mRNAs detected by RT-PCR. These positive cells showed high levels of PLC and aAMP production in response to PTH stimulation.</p><p><b>CONCLUSION</b>The HEK293 cell lines with stable expression of PTH1R or DSEL gene established in this study provide useful cell models for studying the physiological functions of PTH peptides.</p>

Hiperparatireoidismo secundário: fatores prognósticos de recidiva atribuída ao implante após paratireoidectomia total e auto-implante / Secondary hyperparathyroidism: prognostic factors of graft-dependent recurrence after total parathyroidectomy and parathyroid autotransplantation

Nos casos de hiperparatireoidismo secundário onde não é possível o tratamento clínico, é indicada a paratireoidectomia. No Serviço de Cirurgia de Cabeça e Pescoço do Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, o tipo de cirurgia utilizada é a paratireoidectomia total com auto-implante de paratireóide em membro superior. Nesses casos, ao contrário da paratireoidectomia total, pode haver recidiva do hiperparatireoidismo no sítio do implante, com sintomas sistêmicos e com necessidade de intervenção para retirada do tecido hiperplásico. Já na paratireoidectomia total, há hipoparatireoidismo definitivo e risco de doença óssea adinâmica. O presente estudo tem como escopo avaliar os pacientes submetidos a paratireoidectomia com implante e esclarecer se há fatores clínicos e de imunohistoquímica que possam indicar antes da cirurgia algum risco de recidiva no implante.

When clinical treatment of secondary hyperparathyroidism fails, parathyroidectomy is mandatory. Total parathyroidectomy and immediate parathyroid autotransplantation in the forearm is the treatment of choice at Head and Neck Surgery of Hospital das Clínicas of University of São Paulo Medical School. In this cases, recurrent hyperparathyroidism may be caused by hyperplastic graft tissue. Without autotransplantation, adinamic bone disease may occur. The present study seek to evaluate patients submitted to total parathyroidectomy and autotransplantation and try to clarify clinical or immunohistochemical.

Homeostasis del calcio: rol de la parathormona y el péptido relacionado a la parathormona. Aplicaciones clínicas y ensayos específicos / Calcium homeostasis: parathormone and parathormone related protein clinical usefulness and specific assays

Para comprender los desórdenes del metabolismo óseo y mineral es necesario tener un conocimiento integrado del sistema hormeostático del calcio y la regulación que sobre él ejercen las hormonas calciotrópicas. Esta revisión presenta un informe actualizado sobre el complejo sistema homeostático que regula y mantiene constante las concentraciones intra y extracelulares de calcio. Hace mención al sensor de calcio que a su vez regula la síntesis y liberación de la parathormona (PTH), principal hormona calciotrópica. También se analizan los mecanismos celulares involucrados en la síntesis, secreción y metabolismo de la PTH, así como sus mecanismos celulares y moleculares que dan lugar a la acción a nivel de los órganos efectores. Se presenta el rol del péptido relacionado a la PTH (PTHrp) sobre el metabolismo óseo y mineral. Dicho péptido es el responsable, en condiciones patológicas, de la hipercalcemia tumoral, pero, además, presenta una acción en condiciones fisiológicas normales tal como ocurre durante el embarazo y la lactancia. Ambas hormonas utilizan el mismo receptor y desencadenan respuestas similares sobre la homeostasis del calcio. Se analizan las dificultades para la determinación bioquímica de la PTH y PTHrp así como los inmunoensayos actualmente disponibles. Finalmente se hace mención a la aplicación clínica de los ensayos de PTH y PTHrp

An update on the discovery, pathophysiological actions, clinical manifestations and possible physiology of parathyroid related peptide

PTHrP has had an unidentified role in medicine since 1930, when Albright described a patient with renal cortical cell carcinoma with hypercalcemia. Since then hypercalcemia has been recognized as the most common paraneoplastic syndrome. At that time the concept of ®ectopic PTH syndrome® was introduced, and remained in literature until the true etiology was finally described. In the early 1970's Roof and Benson presented evidence that PTH in humoral hypercalcemia differed from ®authentic® PTH. This marked the starting point for researchers to try identifying the molecule that mimicked PTH action and structure. This molecule, named parathyroid-related peptide, has been associated to hypercalcemia seen with solid tumors, such as squamous cell carcinoma of the lung and renal cortical cell carcinoma. PTHrP has been demonstrated to have similar actions to PTH but to differ in decreasing osteoblastic activity while increasing osteoclastic activity. The more fascinating finding was the presence of the PTHrP genes throughout the body, mostly the lactating breast as well as the heart, lungs and skin among others. Despite its identification, finding its physiological roles on normal tissue still remains to be clarified