Computerized artifact detection and correction of uroflow curves: towards a more consistent quantitative assessment of maximum flow.

OBJECTIVES: To evaluate a computerized method of artifact detection and correction of uroflow and compare the quantitative assessment of maximum flow obtained by the computer with visual correction by experts. METHODS: A total of 90 randomly chosen flows was scanned into the computer whereafter automated artifact detection and correction was performed according to pre-established rules implemented in the software. Three experts visually corrected the flows using the same artifact detection and correction specifications as the computer. Measuring agreement between different methods of assessment of maximum flow was evaluated by calculating the difference and the standard deviation (SD) of the differences. The repeatability of assessing the maximum flow value by the computer and by expert 1 was assessed by calculating the difference between 2 readings and the coefficient of repeatability. RESULTS: The coefficient of repeatability of maximum flow after detection and correction of artifacts by the computer (0.38 ml/s) was slightly better when compared with the coefficient of repeatability between 2 observations by 1 expert (1.12 ml/s). The interobserver variation for the quantitative assessment of maximum flow appeared to be great. A total of 51% of the maximum flow values assessed by expert 2 was 1 ml/s or more greater than those assessed by expert 1. When comparing the results of the computer with those of the experts, the mean value of maximum flow from expert 1 was 0.71 ml/s smaller than the computer value (p < 0.01), the mean value from expert 2 was 0.53 ml/s greater (p < 0.01) and the mean value from expert 3 was not significantly different (0.25 ml/s greater). The SD of maximum flow after correction by the computer was 0.3 ml/s smaller than the SD of the raw data from the flowmeter and the corrected values by 2 experts. CONCLUSIONS: Computerized artifact detection and correction eliminates an important fraction of the variability of manually corrected maximum flow values. This may lead to smaller sample size requirements, especially in studies where the primary objective is to assess a small (+/- 1 ml/s) difference in mean maximum flow between groups.

Molecular genetics of renal cell carcinoma.

Significant research progress over the last few years has identified several major genetics contributors to RCC. A new classification of RCC validated by cytogenetic and molecular studies has been proposed including nonpapillary, papillary, chromophobe and oncocytic tumors. The cytogenetic analysis of patients with familial RCC, VHL disease and sporadic RCC have shown that WHL gene located on chromosome 3P 25 is a tumor suppressor gene. Other genes may be involved in the development of RCC, however with a less important incidence than VHL gene. Mutations of Rb and P53 genes can be associated with metastatic disease, mutations of the ras gene is rare whereas elevated level of myc oncogene are frequent but of little prognostic value. Controversial the role of ploidy and proliferation markers as independent prognostic factors.

Male sexual impotence in diabetes mellitus: vasculogenic versus neurogenic factors.

In an attempt to understand better the role of vascular and neurogenic alterations in the pathophysiology of diabetic impotence, 29 impotent male patients with diabetes mellitus (DM) were investigated by means of doppler ultrasound examination (DUE) of penile arteries, sacral evoked responses (SERs), peripheral nerve conduction studies, and, in most cases, nocturnal penile tumescence monitoring (NPTM). Fourteen patients showed isolated alterations of penile vascular supply, four isolated alterations of penile segmental innervation, and seven combined vasculogenic and neurogenic abnormalities; finally, in four patients, DUE, SERs, and NPTM were normal. One patient, in spite of the presence of marked vasculogenic and neurogenic alterations, showed nocturnal penile erections. Results confirm that vascular obstruction, more than nerve damage, plays a primary role in the pathophysiology of diabetic erectile failure, and stress the importance of psychogenic factors. The observation that some patients presented marked involvements of both arterial supply and neurological pathways only a few years, or even 1 year, after the diagnosis of the disease, indicates the need of an early screening of the vascular and neurological status, even in asymptomatic patients. Furthermore, all patients with altered SERs had peripheral neuropathy; on the other hand, six patients with peripheral neuropathy had normal SERs. This result stresses the diagnostic importance of the electrophysiologic studies of sacral segmental innervation and indicates further that in a comprehensive diagnostic protocol of diabetic impotence the study of SERs should be performed only in patients with peripheral neuropathy.

Functional electrical stimulation: method to differentiate supraspinal from segmental detrusor hyperreflexia.

Functional electrical stimulation of anal mucosa permits a differential diagnosis between supraspinal and segmental detrusor hyperreflexia. The method introduces an interesting concept on pathophysiology of micturition allowing a better selection of patients for appropriate treatment.

Premature ejaculation: new electrophysiologic approach.

A new diagnostic investigation for premature ejaculation is described. Although the neurophysiologic basis of the test is unknown, it could be a good method for differentiating organic from psychologic ejaculatory dysfunction.