Pathological aging of the vascular endothelium: are endothelial progenitor cells the sentinels of the cardiovascular system?

Aging is associated with vascular endothelial dysfunction, which ultimately leads to atherosclerosis. On the other hand, it is clear that in young patients with risk factors for cardiovascular diseases (CVD), endothelial dysfunction is an early marker of the ongoing atherogenic process. It is therefore tempting to speculate that risk factors for CVD accelerate the aging process. The aging of an endothelial cell (EC) is not chronological but rather dependent on its replication rate. ECs have a finite number of divisions and enter replicative senescence after exhaustion of this potential. Telomere attrition is believed to be responsible for this phenomenon. Upon reaching a critical minimal telomere length, ECs enter a nondividing state of replicative senescence. Recently, endothelial progenitor cells originating from the bone marrow have been isolated from the circulation. They integrate into the endothelial layer of the vessel and contribute to healing, ischemic repair and angiogenesis. A completely new field of investigation is now open. Are endothelial progenitor cells sensitive to the aging process? Do they prevent endothelial dysfunction? Are they the ultimate shield against the damages induced by risk factors for CVD? There are no definite answers to these questions, but the potential of these cells is tremendous and understanding their physiology is essential.     

Lingual artery bifurcation aneurysms for training and evaluation of neurovascular devices

We present a canine lingual artery bifurcation aneurysm and assess its value for training in endovascular techniques and testing new embolic agents. The experimental aneurysm described herein mirrors human bifurcation aneurysms, and with this model, we sought to reproduce endovascular technical difficulties. However, the lesions created in this canine model did not show angiographic or histologic evidence of aneurysmal recurrence. We conclude that this model may be useful for training in endovascular techniques, but because of the lack of sufficient aneurysmal recurrence, it is not suitable for evaluating new embolic agents.     

Positron emission tomography with 18F-fluorodeoxyglucose to predict pathologic response after induction chemotherapy and definitive chemoradiotherapy in head and neck cancer

BACKGROUND: Conventional imaging is limited in identifying persistent disease after organ-preserving therapy for patients with advanced squamous cell carcinoma of the head and neck (SCCHN). We studied the accuracy of positron emission tomography (PET) with (18)F-fluoro-2-deoxy-D-glucose (FDG-PET) in restaging disease in patients with SCCHN after they had undergone induction chemotherapy (ICT) followed by chemoradiotherapy (CRT). METHODS: Forty patients with advanced SCCHN were treated with ICT followed by CRT. FDG-PET imaging was performed to assess for residual cancer at the primary site and in nodal metastases. Two nuclear medicine physicians interpreted PET scans in random sequence. Test characteristics were calculated with pathologic analysis or clinical recurrence as the standard. RESULTS: After induction chemotherapy, PET imaging had a sensitivity of 100% and specificity of 65% for detecting persistent disease at the primary tumor site. After ICT and CRT were completed, the sensitivity and specificity of PET imaging were 67% and 53%, respectively, for detecting occult disease in cervical lymph nodes. CONCLUSIONS: FDG-PET imaging showed some correlation with pathologic response after ICT and CRT in patients with advanced SCCHN. The use of FDG-PET warrants further investigation in this setting.     

Late metastasis after a testicular Sertoli cell tumour

The diagnosis of Sertoli cell tumors is sometimes difficult and can be improved using anti inhibin immunohistochemistry. It is also difficult to establish the prognostic of Sertoli cell tumors. In our observation a high Mib 1 rate (20%) could have be taken in account to decide a better survey or/and a lymphadenectomy, which could have avoided lymph node metastasis in our patient, which was discovered ten years after orchidectomy.     

A large para-renal PEComa

We report the case of a 45-year-old man with a voluminous para-renal mass. The tumor was composed of epithelioid or spindle-shaped eosinophilic and clear cells with some atypia and an elevated mitotic count. The immunohistochemical study was positive for anti-HMB45 antibodies and anti-actin-antibodies and negative for epithelial markers and PS100 antibodies. The diagnosis of epithelioid AML (PEComa) was established. Two years later, recurrence was observed with a voluminous mass in the left upper quadrant of the abdomen, with high cellular density and the same immunohistochemical features. This tumor belongs to the PEComa and is not easy to diagnose clinically and morphologically. The immunohistochemical phenotype is characteristic. AML are usually benign but some epithelioid AMLS outcome can be unfavorable with metastatic dissemination. Criteria of malignancy are not clearly defined in the literature. This case shows that the mitotic count and the tumor size are probably important.     

The pathogenesis of interstitial lung diseases in children

The pathological changes observed in interstitial lung disease (ILD) are characterised by derangements of the alveolar walls. For a long time, the prevailing hypothesis has emphasised the key role of a persistent alveolitis that injures the lung and modulates fibrogenesis, regardless of initiating agents. The current concept on ILD pathogenesis relies on an epithelial/fibroblastic pathway with epithelial injury and activation, formation of subepithelial fibroblast/myofibroblast foci and excessive accumulation of extracellular matrix. An essential step in the restoration of alveolar integrity is the rapid re-epithelialisation of the altered surface, mainly through epithelial proliferation and migration. In the context of lung growth and development in paediatric ILD, it is suggested that the programmed production of mitogenic factors may promote the process of re-epithelialisation and may help to counteract the altered secretion of mediators involved in migration and proliferation of fibroblasts and differentiation into myofibroblasts. This is supported by clinical observations indicating that paediatric ILD is more responsive to therapeutic strategies than adult ILD.