Specially designed vascular prostheses that can be dilated after implantation using a percutaneous transluminal angioplasty (PTA) balloon catheter have been developed. The grafts are made of woven polyester fiber fabrics, the circumferential yarns of which consist of two different types of polyester fiber bundles: One is a straight weak bundle, the other is a strong bundle wound around the former. The graft with an initial diameter of 6 mm could be dilated to 9 mm by luminal inflation of the balloon four to five times at 10 atmospheres (atm) in vitro. After disrupting the weak bundle by the dilatation procedure, the strong bundles were straightened, which maintained the enlarged diameter of the new caliber. Grafts of 6 mm in initial diameter implanted into the thoracic aortas of mongrel dogs for 3 months also could be dilated in vivo by inflating the PTA four to five times at 15 atm, as found in the vitro study. Macroscopic observation revealed that, around the dilated grafts, only a tiny hematoma was formed and nominal subsequent bleeding was observed, which indicated that the dilatation procedure was performed safely. The graft, which enables adaptation of the hydrodynamic property of the graft to the increased blood flow by PTA after implantation, is applicable in a growing child.

Angioplasty, Balloon↗

PubMedDate not supplied

Highly oriented, tubular hybrid vascular tissue for a low pressure circulatory system.

A hierarchically structured hybrid vascular tissue was prepared from vascular cells and collagen. First a hybrid medial tissue was prepared by pouring a cold mixed solution of bovine aortic smooth muscle cells (SMCs) and Type I collagen into a tubular glass mold composed of a mandrel and a sheath (inner diameter, 1.5 mm; outer diameter, 7 mm; length, 7 cm). An SMC incorporating collagenous gel was formed with incubation at 37 degrees C. After the sheath of the mold was removed, the resulting fragile tissue cultured in the medium shrank in a time dependent manner to form an opaque, dense tissue. Seeding at a higher cell density and a lower concentration of collagen resulted in rapid and prominent shrinkage. Morphologic investigation showed that with time, bipolarly elongated SMCs and collagen fiber bundles became positioned around the mandrel. When the mandrel was removed, a tubular hybrid medial tissue was formed. A hybrid vascular tissue with a hierarchical structure was constructed by seeding endothelial cells onto the inner surface of the hybrid medial tissue. Prepared tissues tolerated luminal pressures as great as 100 mmHg and mechanical stress applied during the anastomotic procedure. This method allowed the authors to prepare hybrid medial tissues of predetermined size (specifically inner diameter, wall thickness, and length) and mechanical property, which all depend on the mold design, SMC seeding density, initial collagen concentration, and incubation period. Hybrid vascular tissues may provide physiologic functions such as antithrombogenicity and regulation of vasomotor tone when implanted into a venous system.

Animals↗

PubMedDate not supplied

Self-organized, tubular hybrid vascular tissue composed of vascular cells and collagen for low-pressure-loaded venous system.

A tubular, hierarchically structured hybrid vascular tissue composed of vascular cells and collagen was prepared. First, a cold mixed solution of bovine aortic smooth muscle cells (SMCs) and Type I collagen was poured into a tubular glass mold composed of a mandrel and a sheath (example of dimensions: inner diameter, 1.5 mm; outer diameter, 7 mm; length, 7 cm). Upon incubation at 37 degrees C, an SMC-incorporated collagenous gel was formed. After the sheath was removed, the resulting fragile tissue, when cultured in medium, thinned in a time-dependent manner to form an opaque, dense tissue. Higher SMC seeding density and lower initial collagen concentration induced more rapid and prominent shrinkage of the tissue. Morphologic investigation showed that over time, bipolarly elongated SMCs and collagen fiber bundles became positioned around the mandrel. Both components became circumferentially oriented. When the mandrel was removed, a tubular hybrid medial tissue was formed. A hybrid vascular tissue with a hierarchical structure was constructed by seeding endothelial cells onto the inner surface of the hybrid medial tissue. Prepared tissues tolerated luminal pressures as great as 100 mmHg and mechanical stress applied during an anastomotic procedure. This method allowed us to prepare a tubular hybrid medial tissue of predetermined size (inner diameter, wall thickness, and length) by selecting appropriate mold design, initial collagen concentration, and SMC seeding density. Such hybrid vascular tissues may provide physiological functions when implanted into the venous system.

Animals↗

PubMedDate not supplied

Venous reconstruction using hybrid vascular tissue composed of vascular cells and collagen: tissue regeneration process.

In this study, a tubular hybrid vascular tissue composed of vascular cells and collagen was implanted as a venous substitute, and its remodeling process was histologically investigated. First, a hybrid medial tissue was prepared by pouring a cold mixed solution of canine jugular smooth muscle cells (SMCs) and Type I collagen into a tubular glass mold and subsequent incubation at 37 degrees C. Culture in medium for 10 days produced a dense tubular tissue. Seeding of jugular endothelial cells (ECs) onto the luminal surface of the tissue produced a hybrid vascular tissue with a hierarchical structure. These vascular tissues (inner diameter, 7 mm; length, 3 cm; wall thickness, 1 mm; n = 14) were implanted autologously in the canine posterior vena cava wrapped in Dacron mesh for up to 24 wk. Nine of 14 grafts were patent throughout implantation. In patent grafts, monolayered ECs were oriented in the direction of blood flow at 1 wk. Circumferentially oriented SMCs accumulated at the subendothelial layer and ingrown fibroblasts were sparsely distributed throughout the wall at 12 wk. Contractile phenotype of SMCs was evident at 24 wk. Collagen fibrils, which were sparsely distributed at an early period of implantation, gradually assembled to form fibrous meshes at 24 wk. Sheet-like elastic lamellae were also observed at this time. Marked wall thinning was observed at 12 and 24 wk. The resultant tissues became highly dense. The specific gravity of tissues increased with time, and reached those of natural vessels at 24 wk. Tissue remodeling progressed in a time-dependent manner and appeared to be almost complete within 6 mo of implantation.

Anastomosis, Surgical↗

PubMedDate not supplied

A case of hyperLp(a)aemia, associated with systemic lupus erythematosus, suffering from myocardial infarction and cerebral infarction.

We describe a case of systemic lupus erythematosus (SLE) with nephrotic syndrome who suffered from myocardial infarction and cerebral infarction associated with hyperLp(a)aemia. The proband was an 18-year-old Japanese male who was found to have hypercholesterolemia and hyperLp(a)aemia, with a serum total cholesterol level of 361 mg/dl and a serum Lp(a) level of 197 mg/dl. His father and mother showed higher Lp(a)levels (26 and 56 mg/dl, respectively) than those in normals (18 +/- 0.6 mg/dl, mean +/- SE). Lp(a)glycoprotein phenotypes were examined. The proband had the phenotype S2/4, which is associated with high Lp(a) concentration. His parents had the phenotype S3/4 and S2/4. No cardiovascular diseases were noted in other members of his family. After treatment with CS-514, a competitive inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A reductase. Lp(a) levels decreased from 197 to 121 mg/dl, but still remained abnormally high. LDL apheresis using a Liposorber system was attempted in this patient. Total and LDL cholesterol levels decreased by 57 and 62%, respectively. Lp(a) levels decreased by 68%. These results suggest that LDL apheresis may be an alternative therapy in drug resistant hyperLp(a)aemia.

Adolescent↗

PubMedDate not supplied

An asymptomatic, normotensive sipple syndrome patient with glucose intolerance and hypercholesterolemia, and her kindred.

The proband, a 42-year-old woman without any symptoms or hypertension, was admitted for examination of accidentally discovered bilateral adrenal masses. Physical examination disclosed bilateral nodular goiter and mild sinus tachycardia. Pheochromocytomas and medullary thyroid carcinomas were revealed by biochemical and histopathological examinations. Hypercholesterolemia and abnormal glucose metabolism returned to normal after bilateral total adrenalectomy and thyroidectomy. Screening examination showed four affected family members. Three of them were also asymptomatic and normotensive. In pheochromocytoma patients, normotension, hypercholesterolemia, and impaired glucose metabolism might be signs of excess secretion of epinephrine rather than norepinephrine.

Adrenal Gland Neoplasms↗

PubMedDate not supplied

A study of the clinical significance of lipoprotein (a) in nephrotic syndrome.

Lipoprotein (Lp)(a) concentrations were measured in eight patients with nephrotic syndrome in the age range of 8 to 69 yrs. Mean (+/- SE) levels of serum Lp(a) were elevated in the nephrotic patients compared to controls (76.5 +/- 19.7 vs 18.6 +/- 0.9 mg/dl, p less than 0.001). After treatment with prednisolone, Lp(a) concentrations were decreased from 85.2 +/- 21.6 to 42.2 +/- 14.0 mg/dl. During the treatment, serum total cholesterol showed a negative correlation with serum albumin concentration. However, no correlation was noted between Lp(a) and serum albumin concentration. There were no significant correlations between Lp(a) and other lipoprotein lipid and apolipoprotein levels. It was concluded that hyperLp(a)aemia may be an independent risk factor in the development of premature atherosclerosis in patients with nephrotic syndrome.

Adolescent↗