Combining nanotechnology with current biomedical knowledge for the vascular imaging and treatment of atherosclerosis

Activation of vasa vasorum (the microvessels supplying the major arteries) at specific sites in the adventitia initiates their proliferation or 'angiogenesis' concomitant with development of atherosclerotic plaques. Haemorrhagic, leaky blood vessels from unstable plaques proliferate abnormally, are of relatively large calibre but are immature neovessels poorly invested with smooth muscle cells and possess structural weaknesses which may contribute to instability of the plaque by facilitation of inflammatory cell infiltration and haemorrhagic complications. Weak neovascular beds in plaque intima as well as activated adventitial blood vessels are potential targets for molecular imaging and targeted drug therapy, however, the majority of tested, currently available imaging and therapeutic agents have been unsuccessful because of their limited capacity to reach and remain stably within the target tissue or cells in vivo. Nanoparticle technology together with magnetic resonance imaging has allowed the possibility of imaging of neovessels in coronary or carotid plaques, and infusion of nanoparticle suspensions using infusion catheters or implant-based drug delivery represents a novel and potentially much more efficient option for treatment. This review will describe the importance of angiogenesis in mediation of plaque growth and development of plaque instability and go on to investigate the possibility of future design of superparamagnetic/perfluorocarbon-derived nanoparticles for imaging of the vasculature in this disease or which could be directed to the adventitial vasa vasorum or indeed intimal microvessels and which can release active payloads directed against primary key external mitogens and intracellular signalling molecules in endothelial cells responsible for their activation with a view to inhibition of angiogenesis.

Tissue factor induction by aggregated LDL depends on LDL receptor-related protein expression (LRP1) and Rho A translocation in human vascular smooth muscle cells

OBJECTIVE

Low density lipoprotein (LDL) internalized in the vascular wall and modified by binding to extracellular matrix-proteoglycans (ECM) becomes aggregated (agLDL). AgLDL induces tissue factor (TF) expression and activity in human vascular smooth muscle cells (VSMC). TF expression in vascular cells promotes the prothrombotic transformation of the vascular wall. However, the mechanisms by which agLDL induces TF are not known. The aim of this study was to investigate the mechanisms involved in TF activation by extracellular matrix-modified LDL in human VSMC.

METHODS AND RESULTS

AgLDL significantly induces TF expression (real time PCR and Western blot analysis) and procoagulant activity (factor Xa generation test) in human VSMC. HMG-CoA reductase inhibition completely prevents agLDL-induced TF expression and partially inhibits agLDL-TF activation. These effects are reverted by geranylgeranyl pyrophosphate (GGPP) but not by farnesyl pyrophosphate (FPP), suggesting the involvement of a geranylated protein in agLDL-TF induction. AgLDL increases Rho A translocation (2-fold) from the cytoplasm to the cell membrane in control but not in simvastatin-treated VSMC. Exoenzyme C3, a specific Rho A inhibitor, completely prevents agLDL-induced TF overexpression and partially agLDL-TF activation. Blocking LRP1, the receptor of agLDL, with anti-LRP1 antibodies or inhibiting LRP1 expression by small interference RNA treatment (siRNA-LRP1) impairs agLDL-induced TF overexpression and activation.

CONCLUSIONS

These results demonstrate that TF induction by agLDL depends on LRP1 expression and requires Rho A translocation to the cellular membrane.

Linear correlation between stable intracranial pressure decrease and regional cerebral oxygenation improvement following mannitol administration in severe acute head injury patients

OBJECTIVES

We investigated the relationship between stable decrease in intracranial pressure (ICP) following mannitol administration and variations in regional oxygenation (PtiO2) in severe traumatic brain injured (STBI) patients.

METHODS

Fourteen STBI patients (Glasgow Coma Scale score < or = 8) admitted to the neurointensive care unit during a 12-month period were studied. Multiparameter data, including parenchymal tissue oxygen (PtiO2) and carbon dioxide tension, cerebral perfusion pressure, mean arterial pressure; temperature, pH and pressure reactivity index were measured. Point values from 53 mannitol administrations were extracted every five seconds and divided into five consecutive 30-minute epochs. Mean values and trends were identified. Postadministration epoch with maximum decrease in ICP was selected along with the means of the corresponding variables. These data were compared with baseline to derive the delta values. Mean deltaICP was then compared with deltaPtiO2 in each patient using linear correlation.

FINDINGS

In patients with ICP0 > 20 mmHg (group A), PtiO2 increased in 69.6% of samples, whereas in group B (ICP0 < 20 mmHg), PtiO2 increased in only 50% of the samples. There was a significant negative correlation between mean deltaICP and deltaPtiO2 in both groups; Group A: r = -0.79 (P = 0.01); Group B: r = -0.92 (P = 0.01).

CONCLUSIONS

There is a strong negative correlation between stable decrease in ICP following mannitol administration and improvement in regional oxygenation around the peri-contusional area. The data suggest a potentially favourable interaction between mannitol therapy and cerebral internal milieu in STBI patients.

[Long-term functional results in ossicular reconstruction with cartilage]

Optimal hearing is one goal of otologic surgery. This study examines the long-term functional success rate of cartilage as graft material for ossicular chain reconstruction in type III tympanoplasty. A retrospective review of seventy-nine patients having undergone type III tympanoplasty (53 with closed techniques and 26 with open techniques) was made. Lateral graft ("onlay") techniques were used in almost all cases. All operations were performed by one of the authors, a well-established otologic surgeon. Seventy-four percent of the reconstructions were performed in an one-stage procedure. The mean period of follow-up was 54 months (range 1-17 years). The results of air-bone gap closure and complications of the surgery are presented. Our results show that a significant percentage of patients gain a long-term substantial improvement in their hearing with minimal risk. However, this hearing improvement tends to decline eventually in a progressive manner. A post-operative air-bone closure equal or < 30 dB was achieved in 92.2% of the all cases (n = 79) with a mean gain of 9.72 dB. Functional outcomes in closed techniques were slightly better than in open techniques. There were few complications. Perforation and retraction of the tympanic graft were the most common observed complications. In conclusion, cartilage is an available, costless, reliable and technically easy to use graft material for functional reconstructions of the ossicular chain. It is a well-tolerated element in middle ear space as well as by the tympanic membrane, it has a very low risk of extrusion and a good long-term functional viability. Therefore, update cartilage is an interesting option in functional restoration of the ossicular chain as graft placed on the stapes capitulum.

Lupus pernio with involvement of nasal cavity and maxillary sinus

Histological demonstration of sarcoidosis affecting the paranasal sinus is rare in the clinical practice. In this paper, we present a case with a diagnosis of lupus pernio with extensive involvement of the nasal cavity and the right maxillary sinus. Long before being diagnosed as having lupus pernio, the patient had had a long history of nasal obstruction and had been treated surgically without success on 3 occasions. The literature on the topic is reviewed.

Construction of a recombinant wine yeast strain expressing beta-(1,4)-endoglucanase and its use in microvinification processes

A genetic transformation system for an industrial wine yeast strain is presented here. The system is based on the acquisition of cycloheximide resistance and is a direct adaptation of a previously published procedure for brewing yeasts (L. Del Pozo, D. Abarca, M. G. Claros, and A. Jiménez, Curr. Genet. 19:353-358, 1991). Transformants arose at an optimal frequency of 0.5 transformant per microgram of DNA, are stable in the absence of selective pressure, and produce wine in the same way as the untransformed industrial strain. By using this transformation protocol, a filamentous fungal beta-(1,4)-endoglucanase gene has been expressed in an industrial wine yeast under the control of the yeast actin gene promoter. Endoglucanolytic wine yeast secretes the fungal enzyme to the must, producing a wine with an increased fruity aroma.

A New Stereoidal Saponin from Polygonatum officinale

Methanol extract of defatted rhizomes of POLYGONATUM OFFICINALE All. yielded a mixture of steroidal saponins. The structures of polyfuroside and odospiroside have been elucidated.

Antimitotic activity of saponin fractions and extracts from RX. primulae, RX. saponariae and Sem. Hippocastani

The strongest biological activity in the Allium test was shown by Rx. Primulae. The inhibition of the linear growth of the onion roots affected with the extract from 0-2 g of Rx Primulae in 100 ml of water (W0-2) and with the 0-05% solution (S0-05) of the saponin fraction after 24 hrs was about 70% of the blanc halves. The inhibition of mitose affected with W0-2 and S0-05 was 90% and 80% respectively.