Tracheal cartilage - evaluating the potential of a novel biomaterial for reconstructive cardiovascular procedures.

Modern cardiovascular medicine aims for procedures that preferably involve biological materials and, ideally, living implants. Thereby, the regenerative capacity of the target organ may be preserved or even supported, with a potential implant growth capacity during the following time. In the current study we sought to evaluate the integrative capacity of vital and non-vital tracheal cartilage rings (TCRs) of allogenic or xenogenic origin (allo-/xeno-vTCR; allo-/xeno-nvTCR) as biomaterials under the in vivo functional load of the circulatory system. Ovine and porcine vTCRs and nvTCRs were implanted in the mitral valve (MV) position for 3 and 9 months (n = 3 each), respectively, in lambs. MV function and TCR position were analysed by echocardiography. Tissue morphology (planimetry), vitality (live/dead-assay) and implant endothelialization (scanning electron microscopy) were analysed. No functional impairment or significant MV insufficiency or stenosis was observed in any group. TCR shrinkage was observed in all xeno-TCRs and allo-nvTCRs at 3 months. Only TCRs of allogenic groups at 9 months and allo-vTCRs at 3 months showed a ring area comparable to its size at implantation. Moreover, allogenic vital cartilage showed superior tissue integration, greater endothelialization, less inflammation and calcification. Interestingly, in this group viable cartilage cells were found up to 9 months after implantation. Allogenic viable cartilage may represent a well-suited living material for reconstructive cardiovascular procedures, and further studies are warranted to elucidate the benefits of this novel material, particularly as a structurally supportive component in growing recipients.

Surgical treatment of renal artery dissection in 25 patients: indications and results.

OBJECTIVE: Results of surgical revascularization in 25 patients with renal artery dissection (RAD) over 14 years, with mean follow-up of 55.3 months (range, 10-111 months), were analyzed. Indications for surgery were renovascular hypertension and preservation or improvement of kidney function. PATIENTS AND METHODS: Two patients (both 20 years of age) underwent emergency surgery after severe trauma; 23 patients (mean age, 41 years) underwent elective surgery in a chronic stage of disease. Preoperative, postoperative, and follow-up examinations included duplex ultrasound scanning, determination of serum creatinine and urea concentrations, and evaluation of blood pressure control. All long-term patients underwent digital subtraction angiography preoperatively and postoperatively. All histologic specimens of resected renal arteries were re-evaluated by two independent pathologists. RESULTS: Histologic re-evaluation confirmed the traumatic origin in 2 patients who underwent emergency surgery and 1 who underwent elective surgery. Renal artery dissection developed spontaneously, with no histologic signs of trauma or fibromuscular dysplasia, in 22 patients. In 17 revascularized kidneys (61%) a kidney infarction had already developed preoperatively, and the kidneys were diminished in size or function. Results of revascularization and improvement of hypertension depended on preoperative extent of renal infarction. Hypertension resolved or improved in 86% of patients without preoperative kidney damage, but in only 38% with preoperatively damaged kidneys. Kidney function was preserved in 23 of 28 revascularized kidneys (82%). During follow-up, late renal artery occlusion developed in 3 kidneys. CONCLUSIONS: Renal artery dissection can be effectively treated with surgical revascularization. Primary nephrectomy should be considered only in patients with a large ischemic kidney infarction, with significant deterioration of kidney function, to effectively cure or improve severe renovascular hypertension.

Inner layer infarction of the coronary artery wall due to coronary thrombosis.

Cross sections of 112 coronary artery segments from 65 human hearts with coronary thromboses were investigated after postmortem coronary angiography. In almost all cases the inner layers of coronary artery walls adjacent to the obstructing thrombi or to parietal thrombi were infarcted. These infarctions followed nearly the same course as classical infarctions. From 13 hearts with segments occluded by thrombi but without atherosclerotic lesions, 19 specimens were found suitable for quantitative investigations. The 2 segments with the thinnest intima were lacking in inner layer infarctions. The other 17 specimens contained areas of inner layer necrosis of increasing diameter, depending on the thickness of the wall. In each case the media was completely preserved. The mean thickness of the noninfarcted wall tissue was 190+/-28 micro m. This noninfarcted wall tissue was supplied by vasa vasorum in the adventitia located at an average distance of approximately 40 micro m from the media. The knowledge of the supplying areas of the vasa vasorum could help us understand the pathogenesis of necroses in atherosclerotic plaques.

Sequential Morphological Changes in Aflatoxin B1-Induced Liver Tumors During Chronic Administration of Glutathione 1.

The sequential light microscopic changes in aflatoxin B1-induced liver tumors during chronic administration of glutathione were studied. The results suggest that necrosis of neoplastic hepatocytes plays an important role during the regression of tumor growth induced by glutathione.