Segmental aortic wall stiffness from intravascular ultrasound at normal and subnormal aortic pressure in pigs.

Segmental aortic wall stiffness was calculated from intravascular ultrasound images and intravascular pressures in six pigs at normal and subnormal aortic pressures (21 sequences of pressures and areas before and after boli of intravenous nitroglycerin). The wall stiffness was expressed as the pressure-strain elastic modulus (Ep). The Ep was calculated from the formula: Ep = delta PR delta R-1 (P, pressure; R, radius) in two different ways. First from maximal and minimal values of pressure and area. Second as the slope of linear regression line of delta PR as a function of delta R from 29 simultaneous recorded pressures and images. The average Ep value for all sequences in the different segments was 0.58 +/- 0.55 10(5) Pa (Method 1) and 0.50 +/- 0.40 10(5) Pa (Method 2). Ep increased with the distance from the heart at normal aortic pressures. At subnormal aortic pressures after intravenous nitroglycerin this relationship was not so evident. At subnormal aortic pressures the calculated Ep values were significantly reduced in the lower half of the abdominal aorta. The phase lag, i.e. hysteresis, between pressure and diameter was demonstrated. Our study shows the applicability of intravascular ultrasound as a tool to evaluate arterial wall stiffness.     

Calciphylaxis – a topical overview

'Calciphylaxis', a calcification syndrome associated with ischaemic cutaneous necrosis, is acquired naturally in humans in disease states. It is a life and limb-threatening complication, usually observed in patients with renal disease and secondary hyperparathyroidism, but known to occur in the absence of renal or parathyroid disease. The reported mortality rate, which ranges from 60-80%, relates to wound infection, sepsis and organ failure. It is a small-vessel vasculopathy, which is estimated to occur in about 4% of haemodialysis patients. Clinically, violaceous, reticulate areas of cutaneous necrosis and eschar may be evident, particularly in the extremities. In addition to the clinical picture, a raised calcium phosphorous product, an elevated parathyroid hormone level, radiographic evidence of vessel and soft-tissue calcification and the finding of mural calcification affecting small arteries and arterioles on histopathology help to confirm the diagnosis of this entity which generally has a poor prognosis. A high index of suspicion and an active multidisciplinary management approach, with rigorous attention to wound care and prevention of sepsis, are vital in the management of these patients. In this overview, we discuss the pathophysiology, clinical features and associations, risk factors, diagnosis and management issues relating to calciphylaxis.     

The Sigma-trial protocol: a prospective double-blind multi-centre comparison of laparoscopic versus open elective sigmoid resection in patients with symptomatic diverticulitis

Backround  

Diverticulosis is a common disease in the western society with an incidence of 33–66%. 10–25% of these patients will develop diverticulitis. In order to prevent a high-risk acute operation it is advised to perform elective sigmoid resection after two episodes of diverticulitis in the elderly patient or after one episode in the younger (< 50 years) patient. Open sigmoid resection is still the gold standard, but laparoscopic colon resections seem to have certain advantages over open procedures. On the other hand, a double blind investigation has never been performed. The Sigma-trial is designed to evaluate the presumed advantages of laparoscopic over open sigmoid resections in patients with symptomatic diverticulitis.     

A novel mitochondria-targeting method using special staining for the detection of apoptotic hepatocytes

ABSTRACT

Early detection of apoptotic cells on histological slides is of major importance for both diagnostic and research areas. In the current study, the aim was to propose a convenient method to stain the mitochondria and establish whether hepatocytes undergoing apoptosis can be identified in tissue sections using the proposed method. Liver tissue from five adult chinchillas was fixed with 10% neutral buffered formalin for Goldner’s trichrome (GT) and Groat’s iron hematoxylin and eosin (HE) stains and with Kolster’s fixative for the Heidenhain’s iron hematoxylin procedure. The HE and GT-stained sections showed the morphological features consistent with apoptosis i.e., homogenous intensely acidophilic cytoplasm, cell shrinkage with an irregular outline, nuclear shrinkage with cloudy karyoplasm, and karyopyknosis in the late stage. Sections stained with Heidenhain’s iron hematoxylin method was used to pinpoint mitochondria and revealed cells which were undergoing the first stages of the apoptosis process i.e., disappearance of mitochondria from the cell, chromatin condensation and margination, paracentral localization of nucleoli, and vacuolated nuclei. In more advanced stages of apoptosis, cells presented significant nuclear and cytoplasmic changes. It was concluded that this is the first report targeting the mitochondria, by performing inexpensive histological staining techniques, in order to assess dead cells in situ.