"Smart" alginate-hydroxypropylcellulose microbeads for controlled release of heparin.

"Smart" (thermosensitive) alginate-hydroxypropylcellulose (Alg/HPC) microbeads for controlled release of heparin were synthesized and the release profiles at various temperatures and for various alginate/HPC compositions were measured. Microbeads of regular spherical shape (ca. 3 microm in diameter) containing efficiently encapsulated heparin were obtained using an emulsification method. The internal structure of the bead was estimated by fluorescence microscopy using dansyl alginate as a labelled component. The microbeads surface structure and morphology were imaged in a dry state using scanning electron microscopy (SEM) and in water using atomic force microscopy (AFM). The microbead surface was shown to be covered by the regular network of pores with a mesh of ca. 30-60 nm. Lower critical solution temperature (LCST) of the Alg/HPC systems was measured spectrophotometrically (cloud point measurements). Heparin release profiles were obtained based on spectrophotometric detection of heparin complex with Azure A. Three-stage sustained release for at least 16 days was observed at 37 degrees C. This was correlated with the size of the pores present at the surface of microbeads. The release profile can be controlled by the temperature and composition of the Alg/HPC microbeads.

PDGF-C and -D and their receptors PDGFR-alpha and PDGFR-beta in atherosclerotic human arteries.

BACKGROUND: Platelet derived growth factors (PDGFs) are mitogens for fibroblasts and smooth muscle cells. This growth factor family contains four members PDGF-A, PDGF-B, PDGF-C and PDGF-D. Biology of recently discovered PDGF-C and PDGF-D is not well-established. Here we studied the expression of PDGF-C and PDGF-D and their receptors PDGFR-alpha and PDGFR-beta in normal and atherosclerotic human arteries. MATERIALS AND METHODS: Human arterial samples from amputations and autopsies were classified according to the atherosclerotic stage and the expression of PDGF-C and PDGF-D proteins and their receptors was studied by immunohistochemistry. In situ hybridization and reverse transcriptase-PCR were used to study mRNA expression. RESULTS: Both growth factors were expressed in medial smooth muscle cells (SMCs) in normal arteries and atherosclerotic lesions. However, clear differences were found in the expression profiles in endothelium: PDGF-C was strongly expressed in endothelial cells in both normal arteries and lesions whereas PDGF-D was only weakly expressed in endothelium. PDGF-C expression was very prominent in lesion macrophages. PDGF-D was expressed throughout the artery wall in lesions. PDGFR-alpha expression was strong in endothelium and in lesion macrophage-rich areas, whereas PDGFR-beta was mostly expressed in SMCs. CONCLUSIONS: Our results suggest that PDGF-C may play an important role in endothelium in normal and atherosclerotic arteries and in macrophages in lesions. PDGF-D was expressed in all types of lesions with the same intensity and thus differs from the expression of PDGF-C.

Relationships between phase morphology and deformation mechanisms in polymer nanocomposite nanofibres prepared by an electrospinning process.

Relationships between phase morphology and mechanical deformation processes in various electrospun polymer nanocomposite nanofibres (PNCNFs) containing different types of one-, two- and three-dimensional nanofiller have been investigated by transmission electron microscopy using in situ tensile techniques. From the study of the phase structure of electrospun PNCNFs, two morphological standard types are classified for the analysis of deformation mechanisms: the binary system (polymer matrix and nanofillers), and the ternary system (polymer matrix, nanofillers and nanopores on the fibres surface). According to these categories, deformation processes have been characterized, and different schematic models for these processes are proposed. The finding of importance in the present work is a brittle-to-ductile transition in polymer nanocomposite fibres during in situ tensile deformation processes. This unique feature in the deformation behaviour of electrospun PNCNFs provides an optimal balance of stiffness, strength and toughness for use as reinforcing elements in a polymer based composite of a new kind.

Ventricular standstill complicating left heart catheterization in the presence of uncomplicated right bundle branch block.

We report the unusual occurrence of complete heart block during attempted right coronary artery cannulation in a patient with pre-existing uncomplicated right bundle branch block (RBBB). This complication occurred due to accidental impingement of the Judkin's right coronary catheter on the left bundle when it transiently slipped across the aortic valve. The block resolved without any complication.

Contralateral femoral neuropathy: an unusual complication of anticoagulation following PTCA.

This case report describes the occurrence of femoral neuropathy secondary to a hematoma of the iliacus muscle. This unusual complication was a result of heparin therapy following Percutaneous Transluminal Coronary Angioplasty (PTCA). We have reviewed the anatomic correlates, mechanism, and treatment options of this condition.

Percutaneous aortic valvuloplasty procedure and implications for nursing.

Percutaneous transluminal aortic balloon valvuloplasty (PTABV) is a procedure performed in the cardiac catheterization laboratory for some patients with severe calcific aortic stenosis. A review of the literature indicated that the procedure was beneficial to elderly patients or those who were poor candidates for surgery. The common complications of PTABV include bleeding at the catheterization site and vagal reactions during groin compression. Nursing implications in the cardiac catheterization laboratory involve ensuring patient comfort, managing the effects of cardiac instrumentation, and monitoring vital signs and vascular integrity. Post-PTABV nursing diagnoses include: (1) potential for injury or hemorrhage, (2) potential for alteration in cardiac output, (3) potential for alteration in tissue perfusion, (4) alteration in comfort, (5) potential for infection, and (6) knowledge deficits.

Esophageal-atrial fistula.

We report an unusual case of an esophageal-atrial fistula in a patient with CREST (calcinosis, Raynaud's phenomenon, esophagitis, sclerodactyly, telangiectasia) variant of scleroderma. An ulcer in Barrett's esophagus perforated into the left atrium and led to systemic embolization and cerebral abscess. A review of similar reports of esophageal-atrial fistula reveals a symptom complex that includes chronic esophageal pathology, gastrointestinal bleeding, and neurological signs. An antemortem diagnosis has never been made.

Anomalous right coronary artery arising from left mainstem.

Various coronary artery anomalies occur in both symptomatic and asymptomatic individuals. We have described a unique case of an aberrant right coronary artery arising from the left mainstem, resulting in clinical myocardial infarction in the absence of coronary atherosclerosis. Though different anomalies of the right coronary artery have been described, we feel this case is unique in that the right coronary artery arises from the left mainstem, truly forming a single coronary artery.