Dietary L-arginine improves NO-dependent vasodilator function in cholesterol-fed rabbits and completely blocks the progression of plaques via restoration of NO synthase substrate availability and reduction of vascular oxidative stress. Lovastatin treatment has a weaker inhibitory effect on the progression of atherosclerosis and no effect on vascular NO elaboration, which may be due to its stimulatory effect on vascular superoxide radical generation.

Summary Although patients with superficial bladder cancer (Ta, TI) have a generally good prognosis, those patients who develop muscle-invasive tumours or metastatic disease at recurrence do poorly clinically. In the current study 69 patients undergoing complete uansurethral resection for superficial transitonal cell cancer of the bladder were investigated for different clinical and biological characteristics as possible prognostic factors: age, sex, performance of instillation therapy and immunohistochemical determination of mutational inactivation of p53 tumour-suppressor gene (monoclonal antibody PAb 1801) as weUl as immunohistochemical determination of the proliferation rate by staining for PCNA (proliferating ceUl nuclear antigen) (monoclonal antibody PC 10). After a median foHow-up of 45.8 months, 12 of 14 patients (85.7%) with more than 20% of cells positive for p53 had disease progression with muscle-invasive growth compared with only one of 55 patients (1.8%) negative for p53 (P <0.01, x2 test). During univariate analysis histological grade (G, vs G2) (P = 0.0373), positivity for PCNA (>60% of ceUls) (P =0.0033) and positivity for p53 (P <0.001) were significant prognostic factors for disease progression (log-rank test), while during multivariate analysis only positivity for p53 was a significant predictor for relapse of bladder cancer (P = 0.0029) (multivariate Cox regression analysis). The immunohistochemical detection of mutations of the p53 gene has been demonstrated to be a reliable, easily performed and thereby widely available technique for the investigation of fresh-frozen or paraffin-embedded tumour specimens. The results demonstrate the important role of the p53 tumoursuppressor gene protein in the development and for the progression of bladder cancer. If the high prognostic value of p53 mutations in superficial bladder cancer is confirmed in larger prospective trials, more aggressive therapeutic strategies could be discussed for patients with p53 mutations in their tumour specimens.

L-arginine, the precursor of endogenous nitric oxide (NO), has been shown to enhance endothelial function and to reduce the progression of atherosclerosis in cholesterol-fed rabbits. In the present study, we investigated whether myointimal cell proliferation is enhanced in hypercholesterolaemic rabbit aorta and whether chronic treatment of the rabbits with L-arginine or with the NO synthase inhibitor L-NAME influences this proliferative response and vascular monocyte accumulation. Rabbits were fed 1% cholesterol or normal rabbit chow for 12 weeks. Subgroups of cholesterol-fed rabbits were treated with oral L-arginine (2.25%) or L-NAME (3 mg/dl) in drinking water. Myointimal cell proliferation was quantified in aortic segments by immunohistochemical detection of bromodeoxyuridine (BrdU) incorporation into nuclear DNA; vascular monocyte accumulation was assessed by immunohistochemistry using a monoclonal anti-macrophage/monocyte antibody (RAM-11). Plasma levels of L-arginine and the endogenous NO synthase inhibitor, ADMA, were quantified by high-performance liquid chromatography (HPLC). Cholesterol feeding increased the aortic intima/media (I/M) ratio, which was not measurable in the control group, to 1.9 +/- 0.3. This was paralleled by enhanced cell proliferation (cholesterol, 2.4 +/- 0.2%; P < 0.05; control, 0.02 +/- 0.001% BrdU-positive cells per 72 h) and vascular monocyte accumulation. Double immunostaining for BrdU and alpha-actin showed that about two thirds of the proliferating cells were smooth muscle cells. ADMA levels increased from 0.8 +/- 0.1 micromol/l to 2.2 +/- 0.2 micromol/l in cholesterol-fed rabbits, but were unchanged by L-arginine or L-NAME treatment. Myointimal proliferation and intima/media ratios were correlated with ADMA plasma levels. Dietary L-arginine reduced monocyte accumulation by 85 +/- 2% (P < 0.05 vs cholesterol), myointimal cell proliferation (1.8 +/- 0.3% per 72 h; P < 0.05) and intimal thickening (I/M ratio: 0.7 +/- 0.2), whereas the inhibitor of NO synthase, L-NAME, further increased cell proliferation to 3.1 +/- 0.4% per 72 h (P < 0.05). No significant difference was observed in vascular monocyte infiltration between the cholesterol and L-NAME groups. We conclude that cell proliferation and vascular monocyte accumulation are enhanced in hypercholesterolaemic rabbit aorta. These atherogenic effects can be attenuated by dietary L-arginine. Decreased NO formation might underlie the enhanced monocyte accumulation and cell proliferation in hypercholesterolaemic rabbit aorta. The observed inhibition of cell proliferation adds to our understanding of the antiatherosclerotic effects of L-arginine in vivo.

Shape irregularities of intracranial aneurysms may indicate an increased risk of rupture. To quantify morphological differences, Fourier analysis of the shape of intracranial aneurysms was introduced. We compared the morphology of 45 unruptured (UIA) and 46 ruptured intracranial aneurysms (RIA) in 70 consecutive patients on the basis of 3D-rotational angiography. Fourier analysis, coefficient of roundness and qualitative shape assessment were determined for each aneurysm. Morphometric analysis revealed significantly smaller coefficient of roundness (P < 0.02) and higher values for Fourier amplitudes numbers 2, 3 and 7 (P < 0.01) in the RIA group, indicating more complex and irregular morphology in RIA. Qualitative assessment from 3D-reconstructions showed surface irregularities in 78% of RIA and 42% of UIA (P < 0.05). Our data have shown significant differences in shape between RIA and UIA, and further developments of Fourier analysis may provide an objective factor for the assessment of the risk of rupture.

In this review, the results of previous histomorphometric studies of brain tumours are summarized and discussed with respect to their potential value for diagnostic purposes and for tumour research. In the majority of these studies, human gliomas were investigated. In a few studies, human meningiomas and other human or experimental tumour types were investigated. A computerized image analysis system was used for the morphometric analyses in most studies. The three main histologic structures examined were tumour cell nuclei, nucleolar organizer regions and tumour vessels. The current state of knowledge provides evidence that a diagnostic benefit could be provided by histomorphometric investigations of brain tumours, especially for grading of gliomas and with respect to independent prognostic information. Additional studies are necessary to delineate the spectrum of histomorphometric parameters and the investigation of their prognostic significance for cases with the same tumour type and tumour grade. Together with many recently published observations in this field, this review shows that histomorphometry is an important approach towards the investigation of brain tumour biology.