SUMMARY. To test the hypothesis that atherosclerosis impairs endothelium-dependent vascular relaxation, we examined the effect of the endothelium-dependent vasodilators acetylcholine and thrombin and the endothehum-independent vasodilator nitroglycerin on iliac arteries from normal cynomolgus monkeys and cynomolgus monkeys with diet-induced atherosclerosis. Rings of iliac artery were suspended in organ chambers at their optimal length for generating tension. After preconstriction with prostaglandin F2,,, cumulative concentration-response curves to acetylcholine, thrombin, and nitroglycerin were examined The presence of endothehum was confirmed in each vessel by scanning electron microscopy. Atherosclerotic vessels showed morpholigic evidence of moderate to severe atherosclerosis. Acetylcholine produced a maximal relaxation of 65 ± 10% in the normal group and 27 ± 10% in atherosclerotic vessels (P < 0 05). Thrombin (10 0 U/ml) produced relaxation of 39 ± 9% in the normal group and 13 ± 7% in atherosclerotic iliac arteries (P < 0.05). Nitroglycerin relaxed both normal and atherosclerotic blood vessels to an equal extentmaximal relaxation was 92 ± 4% in normal vessels and 98 ± 2% in atherosclerotic vessels To determine if hypercholesterolemia alone produces an abnormality in endothelium-dependent relaxation, we performed two additional studies First, because veins are exposed to hypercholesterolemia, but do not develop atherosclerosis, we studied relaxation responses to acetylcholine and thrombin in veins from normal monkeys and monkeys with diet-induced atherosclerosis. Veins from normal and atherosclerotic monkeys relaxed to a similar extent upon exposure to the endothelium-dependent vasodilators acetylcholine and thrombin Second, we studied relaxation responses to acetylcholine, thrombin, and nitroglycerin in left circumflex coronary arteries from normal dogs and dogs fed a hypercholesterolemic diet for 4-5 weeks when serum cholesterol levels were elevated (serum cholesterol 442 ± 14 mg/dl), but before the onset of atherosclerosis. The endothelium-dependent vasodilators acetylcholine and thrombin produced equivalent degrees of relaxation in artenes removed from normal and hypercholesterolemic dogs These studies demonstrate that atherosclerosis impairs endothelium-dependent relaxation in primate iliac arteries, and that this impairment is not due to a generalized defect in the endothelium caused by hypercholesterolemia, but requires the presence of atherosclerosis (Che Res 58: 783-789, 1986)
Atherosclerosis results in impaired relaxation to acetylcholine, thrombin, and the calcium ionophore A23187, all agents that require the presence of endothelium. We now report that dietary treatment of atherosclerosis in monkeys not only produces morphological improvement of the atherosclerotic lesion but restores endothelium-dependent vascular relaxation to normal. ]Because the intima remains thickened after regression of atherosclerosis, these studies suggest that intimal thickening which is present in both atherosclerotic vessels and after regression of atherosclerosis does not prevent the endothelium-derived relaxing factor from reaching the underlying vascular smooth muscle.
Keratin 5 (K5) is present in the basal layer of a stratified squamous keratinized and non-keratinized epithelium. K5 and K14 have been demonstrated in the mucosa and tumors of the oral cavity, oropharynx, hypopharynx and larynx, and in the mitotic active basal cells of a stratified squamous epithelium. The aim of the present study was to assess K5 expression in squamocellular carcinoma with various localizations in the head and neck. A total of 13 biopsy fragments were included from patients diagnosed with squamocellular carcinoma of the larynx area (n=2), pharynx (n=2), hard palate (n=1), tongue (n=2), submandibular (n=1), lip (n=1), gingival sulcus (n=1), nasal pyramid (n=1), maxilla (n=1) and zygomatic (n=1). The immunohistochemical staining for K5 was evaluated according to the following score criteria: 0 (0% positive cells); 1 (<10% positive cells); 2 (10–30% positive cells); and 3 (>30% positive cells). K5 expression was observed in all squamocellular carcinomas included in the present study with scores between 1 and 3. For well- and moderately-differentiated histopathological types, a maximum score of 3 was recorded for all of the cases, not including the laryngeal area, which presented a score of 2. The following scores were identified in the regions of the poorly differentiated carcinomas: Jaw, 3; gingival sulcus, 2; and tongue and submandibular area, 1. These observations may aid with an improved stratification of head and neck squamocellular carcinoma, thus improving the diagnosis and treatment strategies for this type of cancer.
The aim of this study was to compare the conventional healing screw with custom healing screw in terms of maintenance of soft tissue architecture. Twenty-four patients who underwent single tooth extraction and single immediate implant placement were included in the study. Twelve patients were treated with conventional healing screw after immediate implant placement (control group) and 12 were treated with screwretained custom healing screw (test group). After minimally traumatic tooth extraction, a temporary abutment was fabricated utilizing flowable composite, which adapted to the socket architecture, to serve as a customized healing screw. In order to evaluate soft tissue remodeling in all cases, digital impressions were made before tooth extraction, at implant insertion, at 6 months after insertion, and after placement of the final restorations. After 6 months of the Osseo integrated period, the custom healing screw served successfully as a tooth profile for peri-implant tissue. In cases of implants with conventional healing screw, soft tissue remodeling around the implants is observed, in contrast to cases of custom healing abutments. Correct design of a healing abutment is important for maintaining the emergence contour in cases of immediate implant placement. In our study, a considerable difference was observed between the standard healing screw and customized healing screw. The selection between provisional restoration and customized healing abutment is only based on esthetic considerations.
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