Monomeric C-reactive protein--a key molecule driving development of Alzheimer's disease associated with brain ischaemia?

Alzheimer's disease (AD) increases dramatically in patients with ischaemic stroke. Monomeric C-reactive protein (mCRP) appears in the ECM of ischaemic tissue after stroke, associating with microvasculature, neurons and AD-plaques, Aß, also, being able to dissociate native-CRP into inflammatory, mCRP in vivo. Here, mCRP injected into the hippocampal region of mice was retained within the retrosplenial tract of the dorsal 3rd ventrical and surrounding major vessels. Mice developed behavioural/cognitive deficits within 1 month, concomitant with mCRP staining within abnormal looking neurons expressing p-tau and in beta-amyloid 1-42-plaque positive regions. mCRP co-localised with CD105 in microvessels suggesting angiogenesis. Phospho-arrays/Western blotting identified signalling activation in endothelial cells and neurons through p-IRS-1, p-Tau and p-ERK1/2-which was blocked following pre-incubation with mCRP-antibody. mCRP increased vascular monolayer permeability and gap junctions, increased NCAM expression and produced haemorrhagic angiogenesis in mouse matrigel implants. mCRP induced tau244-372 aggregation and assembly in vitro. IHC study of human AD/stroke patients revealed co-localization of mCRP with Aß plaques, tau-like fibrils and IRS-1/P-Tau positive neurons and high mCRP-levels spreading from infarcted core regions matched reduced expression of Aß/Tau. mCRP may be responsible for promoting dementia after ischaemia and mCRP clearance could inform therapeutic avenues to reduce the risk of future dementia.

Animal models for bisphosphonate-related osteonecrosis of the jaws--an appraisal.

The prolonged use of bisphosphonates has been shown to cause a condition termed 'bisphosphonate related osteonecrosis of the jaws' (BRONJ). BRONJ is a disease entity which has only been described relatively recently, and its multi-factorial aetiology is yet to be fully elucidated. Therefore, the treatment of BRONJ lesions remains a challenge, and animal models are necessary to assist researchers in better understanding the disease. This has led to the recent publication of a number of studies utilising a variety of animal models of BRONJ. This review outlines the factors to be considered when selecting an animal model for BRONJ and discusses the current literature in this rapidly progressing field of research. It is important to consider the applicability of a given model to the clinical condition presenting in humans, and to this end, thorough characterisation of the clinical, histological, radiographic and systemic features is necessary. The development of a clinical lesion is an important consideration in terms of choosing a relevant model, and it appears clear that surgical manipulation, generally involving tooth extraction, is necessary for successful induction of the classic 'clinical' lesion of BRONJ.

Pathophysiology of the vascular wall and its relevance for cerebrovascular disorders in aged rodents.

Chronic hypertension and cerebral amyloid angiopathy (CAA) are the main pathologies which can induce the rupture of cerebral vessels and intracerebral hemorrhages, as a result of degenerative changes in the vascular wall. A lot of progress has been made in this direction since the successful creation of the first mouse model for the study of Alzheimer's disease (AD), as the spectrum of AD pathology includes a plethora of changes found in pure cerebrovascular diseases. We describe here some of these mouse models having important vascular changes that parallel human AD pathology, and more importantly, we show how these models have helped us understand more about the mechanisms that lead to CAA formation. An important cellular event associated with reduced structural and functional recovery after stroke in aged animals is the early formation of a scar in the infarcted region that impairs subsequent neural recovery and repair. We review recent evidence showing that the rapid formation of the glial scar following stroke in aged rats is associated with premature cellular proliferation that originates primarily from the walls of capillaries in the corpus callosum adjacent to the infarcted region. After stroke several vascular mechanisms are turned-on immediately to protect the brain from further damage and help subsequent neuroregeneration and functional recovery. Although does occur after stroke, vasculogenesis is overshadowed in its protective/restorative role by the angiogenesis and arteriogenesis. Understanding the basic mechanisms underlying functional recovery after cerebral stroke in aging subjects is likely to yield new insights into the treatment of brain injury in the clinic.

Follicular variant of papillary thyroid carcinoma: a diagnostic challenge for clinicians and pathologists.

The follicular variant of papillary thyroid carcinoma (FVPTC) presents a type of papillary thyroid cancer that has created continuous diagnosis and treatment controversies among clinicians and pathologists. In this review, we describe the nomenclature, the clinical features, diagnostic problems and the molecular biology of FVPTC. It is important for clinicians to understand this entity as the diagnosis and management of this group of patient may be different from other patients with conventional PTC. The literature suggests that FVPTC behaves in a way similar, clinically, to conventional papillary thyroid carcinoma. However, there are some genotypic differences which may characterise this neoplasm. These parameters may account for the phenotypic variation described by some scientists in this type of cancer. Further understanding can only be achieved by defining strict pathological criteria, in-depth study of the molecular biology and long term follow-up of the optional patients with FVPTC.

Modified variant of the Rieske iron-sulfur protein in the hippocampus of kindled rats and human epileptic patients.

Kindled seizures are widely used to model epileptogenesis, but the molecular mechanisms underlying the attainment of kindling status are largely unknown. Recently we showed that achievement of kindling status in the Sprague-Dawley rat is associated with a critical developmental interval of 25 +/- 1 days; the identification of this long, well-defined developmental interval for inducing kindling status makes possible a dissection of the cellular and genetic events underlying this phenomenon and its relationship to normal and pathological brain function. Now we report the identification, by proteomics, of a modified variant of the Rieske iron-sulfur protein, a component of the mitochondrial cytochrome bc1 complex, whose isoelectric point is shifted toward more alkaline values in the hippocampus of kindled rats. By immunohistochemistry the Rieske protein is well-expressed in the hippocampus except in the CA1 subfield, a region of selective vulnerability to seizures in humans and animal models. We also noted an asymmetric, selective expression of the Rieske protein in the subgranular neurons of the dorsal dentate gyrus, a region implicated in neurogenesis. Abnormal changes in Rieske protein immunoreactivity also were found in sections obtained from human epileptic patients. These results suggest that the Rieske protein may play a role in the response of neurons to seizure activity and could give important new insights into the molecular pathogenesis of epilepsy.

Affinity constants and beta-adrenoceptor reserves for isoprenaline on cardiac tissue from normotensive and hypertensive rats.

To determine whether there are differences in cardiac beta-adrenoceptor responsiveness, isoprenaline affinity constants and fractional beta-adrenoceptor occupancy-response relationships for isoprenaline in the early stages of established hypertension, we studied the effects of bromoacetylalprenololmenthane (BAAM) and ([3,5-diamino-6-chloro-N-(1[N-beta-(2-hydroxyl-3-alpha-naphthoxypropy lamino)ethylcarbamoyl]-1-methylethyl)-pyrazine-2-carboxamide (ICI 147 798), slowly reversible beta-adrenoceptor antagonists, on the isoprenaline responses of the left ventricular papillary muscle and the left and right atria of 6-month-old Wistar Kyoto rats (WKY) and spontaneously hypertensive rats (SHR). The papillary muscles, but not the right and left atria, of the SHR were less responsive to isoprenaline than those of the WKY. The isoprenaline pD2 values (the negative logarithms of the molar concentrations of agonist producing 50% of the maximum response) were 7.72 and 8.00 on the SHR and WKY papillary muscles, respectively. On the WKY papillary muscle the isoprenaline KA values were 2-3 x 10(-6) M, which is as expected for isoprenaline at beta1 or beta2-adrenoceptors. Isoprenaline had 100-fold greater affinity on the WKY and SHR left atria than on the papillary muscles; the isoprenaline KA values were 2-4 x 10(-8) M. On the WKY papillary muscle and left atrium, isoprenaline had to occupy 3-4% of the beta-adrenoceptors to produce a 50% maximum response; on the WKY papillary muscle and left atrium isoprenaline had to occupy 25-35% and 55%, respectively, of the beta-adrenoceptors to produce a 90% maximum response. The SHR papillary muscles and left atrium had smaller beta-adrenoceptor reserves for isoprenaline than did the WKY tissues. We were unable to obtain isoprenaline KA values on the WKY right atrium. The isoprenaline KA value on the SHR right atrium was 1-4 x 10(-8) M. Because the isoprenaline KA values for the left and right atria are markedly different from those previously reported for isoprenaline at beta1 or beta2-adrenoceptors, we suggest that atypical beta-adrenoceptors might be present on the atria of WKY and SHR. We have also demonstrated a lower beta-adrenoceptor reserve on SHR papillary muscle and atria in the early stages of established hypertension.

[Current possibilities of echography in pneumological diagnosis (preliminary note)]. / Posibilitati actuale ale ecografiei în diagnosticul pneumologic (Nota preliminara).

Various types of echographies are presented, and it is concluded that the bi-dimensional echography, also called type B or echo-tomography is the most useful for the study of pulmonary affections, and of compact formations in contact with the pulmonary tissues. With the aid of Model E.D.B. Unirad sonograph (Technicare, USA), and of the Scintron 5 computer (Scintag, Berthold, Switzerland) 6 patients with pleurisy of various extension, one patient with fibrothorax, and 2 patients with pulmonary tumours have been examined. Five of the cases are presented. Echotomography has demonstrated its usefulness in measuring the thickness of the thoracic wall, in establishing by means of a non-invasive technique the solid or fluid character of pleural affections, in assessing the structure of pachypleuritis and in detecting changes induced by tumours, or atelectasia in the vicinity of the pleura. However, the method does not provide information on round peripheral tumours which do not come into contact with the pleura. Also this method cannot replace other methods already used in the pneumological practice, but can provide supplementary informations without any risks for the patient.

Functional peculiarities of the heart in the aged.

The dynamics of the heart contraction was studied on 126 subjects of different age (3rd--8th decades), using the classical noninvasive method, and the electrocardiogram, the phonocardogram and the external carotid arterial pulse were simultaneously recorded. In a smaller number of cases there was recorded the apexcardiogram or the echogram of the mitral valve. There was ascertained a prolongation of the pre-ejection period (PEP) with advance in age, while the left ventricular ejection time (LVET) was not significantly modified. The LVET/PEP ratio decreased significantly with age. The isovolumic relaxation time, estimated by means of the apexcardiogram, was prolonged in the aged subjects. The echogram of the mitral valve showed a diminution of the E--F slope, demonstrating that the filling rate in the protodiastole decreases in the advanced age. This decrease may reflect a reduction with age in the rate of the opening movement of the mitral valve imposed by the inherent modifications either of the mitral valve or of the left ventricle. The delay of the protodiastolic filling of the ventricle can be attributed to the slowing down of the ventricle relaxation or to the increase of the left ventricle wall stiffness in the aged.

New possibilities in colour echotomography (computer-aided colour echotomography).

The present work discusses the technical bases and clinical significance of colour echography. Connecting the echograph to a high capacity computer through a Videotron permits the processing of colour images with the help of clinical programmes. This increases the accuracy of the diagnosis, and broadens the sphere of application of echography.

Echocardiography in ischemic heart disease.

The kinetics and dimensions of the septum and left posterior ventricular wall as well as left ventricular performance were investigated by echocardiography in 50 patients with painful ischemic heart disease. In 10 cases hypokinesia and low left ventricular performance were found, more marked in those with a history of angina pectoris and myocardial infarction. The utility of this technique for exploring myocardial contractility and its limits is discussed.