Effect of parathyroid-hormone-related protein on human platelet activation

Evidence suggests that PTHrP [PTH (parathyroid hormone)-related protein] can act as an inflammatory mediator in several pathological settings including cardiovascular disease. The aim of the present study was to determine whether PTHrP might be involved in human platelet activation. We used a turbidimetric method to determine platelet aggregation. The expression of PTH1R (PTH type 1 receptor) in human platelets was analysed by Western blot and flow cytometry analyses. PTHrP-(1-36) (10(-7) mol/l) by itself failed to modify the activation of platelets. However, it significantly enhanced ADP-induced platelet activation, and also increased the ability of other agonists (thrombin, collagen and arachidonic acid) to induce platelet aggregation. H89 (10(-6) mol/l) and 25 x 10(-6) mol/l Rp-cAMPS (adenosine 3',5'-cyclic monophosphorothioate Rp-isomer), two protein kinase A inhibitors, and 25 x 10(-9) mol/l bisindolylmaleimide I, a protein kinase C inhibitor, partially decreased the enhancing effect of PTHrP-(1-36) on ADP-induced platelet activation. Meanwhile, 10(-6) mol/l PTHrP-(7-34), a PTH1R antagonist, as well as 10(-5) mol/l PD098059, a MAPK (mitogen-activated protein kinase) inhibitor, or a farnesyltransferase inhibitor abolished this effect of PTHrP-(1-36). Moreover, 10(-7) mol/l PTHrP-(1-36) increased (2-fold over control) MAPK activation in human platelets. PTH1R was detected in platelets, and the number of platelets expressing it on their surface in patients during AMI (acute myocardial infarction) was not different from that in a group of patients with similar cardiovascular risk factors without AMI. Western blot analysis showed that total PTH1R protein levels were markedly higher in platelets from control than those from AMI patients. PTH1R was found in plasma, where its levels were increased in AMI patients compared with controls. In conclusion, human platelets express the PTH1R. PTHrP can interact with this receptor to enhance human platelet activation induced by several agonists through a MAPK-dependent mechanism.     

Epicardial delivery of collagen patches with adipose-derived stem cells in rat and minipig models of chronic myocardial infarction

Although transplantation of adipose-derived stem cells (ADSC) in chronic myocardial infarction (MI) models is associated with functional improvement, its therapeutic value is limited due to poor long-term cell engraftment and survival. Thus, the objective of this study was to examine whether transplantation of collagen patches seeded with ADSC could enhance cell engraftment and improve cardiac function in models of chronic MI. With that purpose, chronically infarcted Sprague–Dawley rats (n = 58) were divided into four groups and transplanted with media, collagen scaffold (CS), rat ADSC, or CS seeded with rat ADSC (CS-rADSC). Cell engraftment, histological changes, and cardiac function were assessed 4 months after transplantation. In addition, Göttingen minipigs (n = 18) were subjected to MI and then transplanted 2 months later with CS or CS seeded with autologous minipig ADSC (CS-pADSC). Functional and histological assessments were performed 3 months post-transplantation. Transplantation of CS-rADSC was associated with increased cell engraftment, significant improvement in cardiac function, myocardial remodeling, and revascularization. Moreover, transplantation of CS-pADSC in the pre-clinical swine model improved cardiac function and was associated with decreased fibrosis and increased vasculogenesis. In summary, transplantation of CS-ADSC resulted in enhanced cell engraftment and was associated with a significant improvement in cardiac function and myocardial remodeling.     

Embarazo ectópico cervical: diagnóstico y tratamiento

We report a case of cervical ectopic pregnancy treated with methotrexate and abdominal hysterectomy.     

Angiotensin II increases parathyroid hormone-related protein (PTHrP) and the type 1 PTH/PTHrP receptor in the kidney

Angiotensin II (AngII) participates in the pathogenesis of kidney damage. Parathyroid hormone (PTH)-related protein (PTHrP), a vasodilator and mitogenic agent, is upregulated during renal injury. The aim of this study was to investigate the potential relation between AngII and PTHrP system in the kidney. Different methods were used to find that both rat mesangial and mouse tubuloepithelial cells express PTHrP and the type 1 PTH/PTHrP receptor (PTH1R). In these cells, AngII increased PTHrP mRNA and protein production. In contrast, PTH1R mRNA was increased in mesangial cells and downregulated in tubular cells, but its protein levels were unmodified in both cells. AT(1) antagonist, but not AT(2), abolished AngII effects on PTHrP/PTH1R. The in vivo effect of AngII was further investigated by systemic infusion (a low dose of 50 ng/kg per min) into normal rats. In controls, PTHrP immunostaining was mainly detected in renal tubules. In AngII-infused rats, PTHrP staining increased in renal tubules and appeared in the glomerulus and the renal vessels. After AngII infusion, PTHR1 staining was markedly increased in all these renal structures at day 3 but remained elevated only in tubules at day 7. The AT(1) antagonist, but not the AT(2), significantly diminished AngII-induced PTHrP and PTHR1 overexpression in the renal tissue, associated with a decrease in tubular damage and fibrosis. The results indicate that AngII regulates renal PTHrP/PTH1R system via AT(1) receptors. These findings demonstrate that PTHrP upregulation occurs in association with the mechanisms of AngII-induced kidney injury.     

Posterior fontanelle sonography: an acoustic window into the neonatal brain

BACKGROUND AND PURPOSE: Sonographic brain studies are classically performed through the anterior fontanelle, but visualization of posterior supratentorial and infratentorial structures is poor with this approach. Posterior fontanelle sonography is recommended for better assessment of these structures. Our purpose was 1) to determine whether sonography of the brain through the posterior fontanelle (PF) improves visualization of brain lesions when added to the routine anterior fontanelle (AF) approach and 2) to describe standardized PF coronal and sagittal sections. METHODS: In this prospective study (conducted from February 1999 to January 2001), PF sonography was added to AF sonography in 165 consecutive premature neonates with a birth weight of < 2000 g. Sonograms were recorded in digital format for re-evaluation at the end of the study. Lesions were grouped as congenital, infectious, hemorrhagic, or hypoxic-ischemic. The chi2 test for paired data and the kappa coefficient were used to compare diagnoses with AF alone and diagnoses with AF plus PF. RESULTS: PF sonography was performed in 164 of 165 patients. Results were normal in 86 and abnormal in 78. The single posterior fossa malformation detected in this series was best delineated with the PF approach. PF sonography increased the diagnostic rate of grade II hemorrhage by 32%. Cerebellar hemorrhage (two patients) and cerebellar abscesses (one patient) were diagnosed by using the PF approach. PF sonography did not contribute to the diagnosis of periventricular leukomalacia. CONCLUSION: Study of the neonatal brain with the addition of PF sonography afforded greater accuracy in detecting intraventricular hemorrhage compared with AF sonography alone, especially when the ventricle was not dilated. The PF approach better defines posterior fossa malformations.