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Radiologic Evaluation of Penile Arterial Anatomy in Arteriogenic Impotence
SEXUAL FUNCTION AND DYSFUNCTION
penile venous leakage. External vacuum devices, intracavernous iqjection or penile prosthesis has been the standard treatment for these patients. Researchers should take advantage of molecular biology techniques to investigate and develop better strategies for the prevention and treatment of vascular disease. If these measures can prevent restenosis of blood vessels, then vascular surgery may become a useful therapy in all patients with vasculogenic impotence. Tom F. Lue, M.D. Integrative Erectile Biology:The Role of Signal Transduction and Cell-To-Cell Communication in Coordinating Corporal Smooth Muscle Tone and Penile Erection G. J. CHRIST, S. RICHARDS AND A. WINKLER, Urology Research Laboratory, Albert Einstein College of Medicine, Bronx, New York Int. J. Impotence Res., 9 69-84, 1997 The contractility of corporal smooth muscle plays a critical role in the entire erectile process in man. Moreover, in the absence of severe vascular disease, or congenital or other structural abnormalities/ malformations, relaxation of the corporal smooth muscle is both necessary and sufficient to elicit a sustained erection. As such, understanding the initiation, maintenance and modulation of corporal smooth muscle tone is an absolute prerequisite to the improved understanding, diagnosis and treatment of erectile dysfunction. Despite this fact, identification of both the precise mechanistic basis by which endogenous and exogenous vasomodulators exert their effects on individual corporal smooth muscle cells, and moreover, the process by which these signals are spread among the diverse array of parenchymal cells in the paired corpora, remains somewhat of a physiological enigma. Therefore, the goal of t h i s report is two-fold first, to review current knowledge of the regulation of corporal smooth muscle tone at the cellular and molecular level; and second, to outline a cogent explanation for the rapid and syncytial integration of the effects of diverse stimuli among corporal smooth muscle cells in the human penis. Vascular Control Mechanisms in Penile Erection: Phylogeny and the Inevitability of Multiple and Overlapping Systems M. A. ADAMS, J. D. BANTING, D. H. MAURICE, A. MOUES AND J. P. W. HEATON, Departments of Pharmacology and Toxicology,and Urology and Human Sexuality Group, Queen’s University, Kingston, Ontario, Canada Int. J. Impotence Res., 9 85-91, 1997 A co-ordinated series of vascular events underlie the generation of a penile erection. The control and regulation of this simple event is, in fact, a complex of interactions occurring at multiple levels. Many of these individual pathways and responses have been studied extensively. The understanding of the necessity for the integration between the individual pathways into a complex of series and parallel coupled mechanisms provides a rationale for the development of a framework of multiple and overlapping systems. This paper sets out some of the principles of integrated and balanced control of vasodilation and vasoconstriction in the penis. In addition, the role of growth induction and regression and the importance of time as a factor in studying penile structure and function is discussed. Editorial Comment: For those who are interested in the basic neurovascular phenomenon in penile erection, these 2 articles should be on the must read list. The authors have presented a state of the art description of various cellular and molecular mechanisms controlling penile smooth muscle and blood vessels. A better understanding of the mechanisms is essential in developing new strategies for future research and management of erectile dysfunction. Tom F. Lue, M.D. Radiologic Evaluation of Penile Arterial Anatomy in Arteriogenic Impotence S. I. WAHL, M. B. RUBINAND C . W.BAKAL, Department of Radiology, Division of Vascular and Znterventionnl Radiology, Albert Einstein College of Medicine, Montefiore Medical Center, Bronx, New York Int. J. Impotence Res., 9 93-97,1997 Functional and anatomic evaluation of penile arterial blood flow is essential in the work up of erectile dysfunction. Duplex ultrasonography is an ideal screening modality with cavernosal mean peak systolic blood flow velocity being the most sensitive predictor of arterial disease. Arterial variability of the penis may affect sonographic evaluation leading to frequent misinterpretation and therefore pudendal arteriography remains the current gold standard for penile arterial evaluation. Appreciation of the type and frequency of anatomic variants and potential collateral routes is important in interpreting penile arteriograms and in evaluating the hemodynamic significance of suspected arterial disease. Editorial Comment: The authors correctly point out that Duplex ultrasonography cannot be used as a guide in penile vascular surgery. Duplex ultrasonography is an excellent screening modality to evaluate intrapenile anatomy and the functional parameters of the cavernous and dorsal arteries. However, if penile vascular surgery is contemplated, assessment of the donor and recipient arteries is necesmry. The size, location and branching pattern of the epigaetric
613
614
RENAL CALCULI, ENDOSCOPY AND LAPAROSCOPY
and dorsal arteries as well as the collateral circulation between the dorsal and the cavernous arteries are crucial in planning the surgical approach. I would perform an epigastric artery to dorsal artery bypass only if the intraluminal pressure gradient of the 2 arteries is more than 10 mm. Hg. If the intraluminal pressure of the 2 arteries is the same, then epigastric artery to dorsal vein anastomosis can be performed. Currently, the measurement can only be done during surgery. It would be an important contribution to vascular surgery if the interventional radiologist were able to measure the intraluminal pressure of the epigastric and dorsal arteries during preoperative pudendal angiography. Tom F.Lue, M.D.
RENAL CALCULI, ENDOSCOPY AND LAF'AROSCOPY Southwestern Internal Medicine Conference: Medical Management of Nephrolithiasis-A New, Simplified Approach for General Practice C. Y. C. PAK, University of Texas Southwestern Medical Center at Dallas, Center for Mineral Metabolism and Clinical Research, Dallas, Texas Amer. J. Med. Sci., 313 215-219, 1997 Considerable progress has been made regarding pathophysiology, diagnosis, and medical prevention of recurrent renal stone formation. The medical approach is not applied widely because of the availability of extracorporeal shockwave lithotripsy and the complexity of medical diagnostic and treatment modalities. In this review, a simplified program for the medical management of stones is described. From analysis of stone risk factors in 24-hour urine specimens, uncomplicated calcium stone disease is separated from other stone diseases. The uncomplicated calcium stone disease, comprising the illness in the majority of patients with recurrent renal calculi, is characterized by normocalcemia, normouricemia, calcium stones, and the absence of urinary tract infection, bowel disease, or marked hyperoxaluria. Uncomplicated calcium stone disease is separated into a hypercalciuric group and a normocalciuric group. In the simplified treatment program, the hypercalciuric group would be offered thiazide plus potassium citrate, whereas the normocalciuric group would receive potassium citrate alone. Editorial Comment: The author provides a simplified method for completing a metabolic evaluation for urolithiasis. T w o 24-hour urine studies are obtained (1with a random diet and 1 with a stone prevention diet). Using a volume marker and specific preservatives in the small collection container, only an aliquot portion of the 24-hour urine needs to be analyzed. While a full analysis of all factors can be done, the author notes that a simplified method is to assess only the levels of calcium, oxalate, uric acid, citrate, pH, sodium and total volume. With this simplified approach the cases are divided according to stone diseases, for example primary hyperparathyroidism, gout, infection stones, cystinuria and primarylenteric hyperoxaluria. With this information patients with calcium stone disease who have normal serum calcium and uric acid levels, and no history of chronic urinary tract infections, bowel disease or marked hyperoxaluria, may be divided into the 2 major categories of normocalciuric and hypercalciuric. The treatment scheme is likewise simplified with the former patients receiving potassium citrate and the latter patients receiving thiazide and potassium citrate, which leaves only a few other therapies for patients with noncalcium stones or with calcium stone related hyperoxaluria. This simplified approach to diagnosing and treating the medical aspects of urolithiasis makes the benefits of directed medical therapy available to all practicing urologists and their patients. Ralph V. Clayman, M.D. The Value of Antibiotic Prophylaxis During Extracorporeal Shock Wave Lithotripsy in the Prevention of Urinary Tract Infections in Patients With Urine Proven Sterile Prior to Treatment A. F. BIERKENS, A. J. M. HENDRIKX, K. Ezz EL DIN,J. J. M. C. H. DE LA ROSETTE, A. HORREVORTS, W. DOESBURG AND F. M. J. DEBRUYNE, Departments of Urology and Medical Statistics, Academic Hospital Nijmegen, Nijmegen, Department of Urology, Catharine Hospital Eindhoven and Department of Medical Microbiology, Rode Kruis Hospital, The Hague, The Netherlands Eur. Urol., 31: 30-35, 1997 Abstract printed in J. Urol., 159 340, 1997
penile venous leakage. External vacuum devices, intracavernous iqjection or penile prosthesis has been the standard treatment for these patients. Researchers should take advantage of molecular biology techniques to investigate and develop better strategies for the prevention and treatment of vascular disease. If these measures can prevent restenosis of blood vessels, then vascular surgery may become a useful therapy in all patients with vasculogenic impotence. Tom F. Lue, M.D. Integrative Erectile Biology:The Role of Signal Transduction and Cell-To-Cell Communication in Coordinating Corporal Smooth Muscle Tone and Penile Erection G. J. CHRIST, S. RICHARDS AND A. WINKLER, Urology Research Laboratory, Albert Einstein College of Medicine, Bronx, New York Int. J. Impotence Res., 9 69-84, 1997 The contractility of corporal smooth muscle plays a critical role in the entire erectile process in man. Moreover, in the absence of severe vascular disease, or congenital or other structural abnormalities/ malformations, relaxation of the corporal smooth muscle is both necessary and sufficient to elicit a sustained erection. As such, understanding the initiation, maintenance and modulation of corporal smooth muscle tone is an absolute prerequisite to the improved understanding, diagnosis and treatment of erectile dysfunction. Despite this fact, identification of both the precise mechanistic basis by which endogenous and exogenous vasomodulators exert their effects on individual corporal smooth muscle cells, and moreover, the process by which these signals are spread among the diverse array of parenchymal cells in the paired corpora, remains somewhat of a physiological enigma. Therefore, the goal of t h i s report is two-fold first, to review current knowledge of the regulation of corporal smooth muscle tone at the cellular and molecular level; and second, to outline a cogent explanation for the rapid and syncytial integration of the effects of diverse stimuli among corporal smooth muscle cells in the human penis. Vascular Control Mechanisms in Penile Erection: Phylogeny and the Inevitability of Multiple and Overlapping Systems M. A. ADAMS, J. D. BANTING, D. H. MAURICE, A. MOUES AND J. P. W. HEATON, Departments of Pharmacology and Toxicology,and Urology and Human Sexuality Group, Queen’s University, Kingston, Ontario, Canada Int. J. Impotence Res., 9 85-91, 1997 A co-ordinated series of vascular events underlie the generation of a penile erection. The control and regulation of this simple event is, in fact, a complex of interactions occurring at multiple levels. Many of these individual pathways and responses have been studied extensively. The understanding of the necessity for the integration between the individual pathways into a complex of series and parallel coupled mechanisms provides a rationale for the development of a framework of multiple and overlapping systems. This paper sets out some of the principles of integrated and balanced control of vasodilation and vasoconstriction in the penis. In addition, the role of growth induction and regression and the importance of time as a factor in studying penile structure and function is discussed. Editorial Comment: For those who are interested in the basic neurovascular phenomenon in penile erection, these 2 articles should be on the must read list. The authors have presented a state of the art description of various cellular and molecular mechanisms controlling penile smooth muscle and blood vessels. A better understanding of the mechanisms is essential in developing new strategies for future research and management of erectile dysfunction. Tom F. Lue, M.D. Radiologic Evaluation of Penile Arterial Anatomy in Arteriogenic Impotence S. I. WAHL, M. B. RUBINAND C . W.BAKAL, Department of Radiology, Division of Vascular and Znterventionnl Radiology, Albert Einstein College of Medicine, Montefiore Medical Center, Bronx, New York Int. J. Impotence Res., 9 93-97,1997 Functional and anatomic evaluation of penile arterial blood flow is essential in the work up of erectile dysfunction. Duplex ultrasonography is an ideal screening modality with cavernosal mean peak systolic blood flow velocity being the most sensitive predictor of arterial disease. Arterial variability of the penis may affect sonographic evaluation leading to frequent misinterpretation and therefore pudendal arteriography remains the current gold standard for penile arterial evaluation. Appreciation of the type and frequency of anatomic variants and potential collateral routes is important in interpreting penile arteriograms and in evaluating the hemodynamic significance of suspected arterial disease. Editorial Comment: The authors correctly point out that Duplex ultrasonography cannot be used as a guide in penile vascular surgery. Duplex ultrasonography is an excellent screening modality to evaluate intrapenile anatomy and the functional parameters of the cavernous and dorsal arteries. However, if penile vascular surgery is contemplated, assessment of the donor and recipient arteries is necesmry. The size, location and branching pattern of the epigaetric
613
614
RENAL CALCULI, ENDOSCOPY AND LAPAROSCOPY
and dorsal arteries as well as the collateral circulation between the dorsal and the cavernous arteries are crucial in planning the surgical approach. I would perform an epigastric artery to dorsal artery bypass only if the intraluminal pressure gradient of the 2 arteries is more than 10 mm. Hg. If the intraluminal pressure of the 2 arteries is the same, then epigastric artery to dorsal vein anastomosis can be performed. Currently, the measurement can only be done during surgery. It would be an important contribution to vascular surgery if the interventional radiologist were able to measure the intraluminal pressure of the epigastric and dorsal arteries during preoperative pudendal angiography. Tom F.Lue, M.D.
RENAL CALCULI, ENDOSCOPY AND LAF'AROSCOPY Southwestern Internal Medicine Conference: Medical Management of Nephrolithiasis-A New, Simplified Approach for General Practice C. Y. C. PAK, University of Texas Southwestern Medical Center at Dallas, Center for Mineral Metabolism and Clinical Research, Dallas, Texas Amer. J. Med. Sci., 313 215-219, 1997 Considerable progress has been made regarding pathophysiology, diagnosis, and medical prevention of recurrent renal stone formation. The medical approach is not applied widely because of the availability of extracorporeal shockwave lithotripsy and the complexity of medical diagnostic and treatment modalities. In this review, a simplified program for the medical management of stones is described. From analysis of stone risk factors in 24-hour urine specimens, uncomplicated calcium stone disease is separated from other stone diseases. The uncomplicated calcium stone disease, comprising the illness in the majority of patients with recurrent renal calculi, is characterized by normocalcemia, normouricemia, calcium stones, and the absence of urinary tract infection, bowel disease, or marked hyperoxaluria. Uncomplicated calcium stone disease is separated into a hypercalciuric group and a normocalciuric group. In the simplified treatment program, the hypercalciuric group would be offered thiazide plus potassium citrate, whereas the normocalciuric group would receive potassium citrate alone. Editorial Comment: The author provides a simplified method for completing a metabolic evaluation for urolithiasis. T w o 24-hour urine studies are obtained (1with a random diet and 1 with a stone prevention diet). Using a volume marker and specific preservatives in the small collection container, only an aliquot portion of the 24-hour urine needs to be analyzed. While a full analysis of all factors can be done, the author notes that a simplified method is to assess only the levels of calcium, oxalate, uric acid, citrate, pH, sodium and total volume. With this simplified approach the cases are divided according to stone diseases, for example primary hyperparathyroidism, gout, infection stones, cystinuria and primarylenteric hyperoxaluria. With this information patients with calcium stone disease who have normal serum calcium and uric acid levels, and no history of chronic urinary tract infections, bowel disease or marked hyperoxaluria, may be divided into the 2 major categories of normocalciuric and hypercalciuric. The treatment scheme is likewise simplified with the former patients receiving potassium citrate and the latter patients receiving thiazide and potassium citrate, which leaves only a few other therapies for patients with noncalcium stones or with calcium stone related hyperoxaluria. This simplified approach to diagnosing and treating the medical aspects of urolithiasis makes the benefits of directed medical therapy available to all practicing urologists and their patients. Ralph V. Clayman, M.D. The Value of Antibiotic Prophylaxis During Extracorporeal Shock Wave Lithotripsy in the Prevention of Urinary Tract Infections in Patients With Urine Proven Sterile Prior to Treatment A. F. BIERKENS, A. J. M. HENDRIKX, K. Ezz EL DIN,J. J. M. C. H. DE LA ROSETTE, A. HORREVORTS, W. DOESBURG AND F. M. J. DEBRUYNE, Departments of Urology and Medical Statistics, Academic Hospital Nijmegen, Nijmegen, Department of Urology, Catharine Hospital Eindhoven and Department of Medical Microbiology, Rode Kruis Hospital, The Hague, The Netherlands Eur. Urol., 31: 30-35, 1997 Abstract printed in J. Urol., 159 340, 1997