Professor (Teaching), Surgery - Anatomy
My main research interest lies in the functional anatomy of the urogenital system particularly in the human. We are using numerous histochemical and immunocytochemical methods to establish the normal pattern and type of autonomic nerve which supply selected regions of the urogenital system including the urinary bladder, ureter and prostate. This data forms the basis of comparison with the results obtained using the same experimental techniques on postoperative samples of refluxing ureters and prostate hypertrophy. Recently we have begun a detailed study on the morphology of the urethral sphincter mechanism particularly in relation to its functional significance in female urinary continence.
We have also begun a study on the structure and autonomic innervation of the detrusor in cases of bladder extrophy. Our objective is to correlate morphology with detrusor function following surgical correction of this clinical condition. This investigation is intended to identify prior to surgery those cases which are most likely to benefit from subsequent operative treatment.
Successful initial surgical management of bladder exstrophy does not always lead to continence. We evaluated the ultrastructure of the exstrophic bladder using electron microscopy (EM) at various stages of reconstruction to determine whether morphology could correlate with the potential for continence.Bladder specimens obtained from 32 patients undergoing various stages of exstrophy reconstruction were evaluated by EM. Specimens were obtained at primary newborn closure (group 1-10), reclosure following failure (group 2-2), bladder neck reconstruction (group 3-9) and augmentation cystoplasty (group 4-11). Evaluation was performed by a single anatomist with experience with EM. Biopsies were separated into those with good, intermediate or poor ultrastructural parameters and then correlated clinically.In group 1, 4 children had good and 2 had intermediate parameters. All showed increased bladder volumes at followup. Four patients had poor parameters and poor bladder growth. The 2 group 2 children had poor parameters and bladder growth. In group 3, 7 of 9 patients had good and 1 had intermediate parameters. Eight of the 9 patients are doing well. Only 3 of the 11 group 4 children had good parameters and an additional 2 had intermediate parameters.Ultrastructural evaluation can identify changes in the bladder that may portend a poor prognosis for eventual continence. Although the correlation was good at bladder closure, some patients with good parameters still had failed reconstruction. Since this is a small study, we continue to recommend reconstruction in all patients who have an adequate bladder template.
View details for DOI 10.1097/01.ju.0000138248.43831.27
View details for Web of Science ID 000223899000057
View details for PubMedID 15371866
View details for Web of Science ID 000179769400003
There is increasing evidence that the progressive dysfunction induced by partial outlet obstruction is mediated by ischemia-reperfusion, and bladder decompensation results from ischemia-reperfusion induced damage to the cellular and subcellular organelle membranes of nerve and smooth muscle, mitochondria and sarcoplasmic reticulum. Tadenan, an extract of Pygeum africanum, is a therapeutic prescribed in Europe to relieve symptoms of obstructive bladder dysfunction secondary to benign prostatic hyperplasia. There is excellent experimental evidence that Tadenan treatment of obstructed rabbits reduces and reverses the progression of bladder decompensation. We determined whether Tadenan therapy can reverse the morphological damage associated with obstructive dysfunction.A total of 36 male New Zealand White rabbits were separated into 6 groups of 6 each. Rabbits in groups 1 and 2 underwent sham operation. For 3 weeks beginning 2 weeks after sham operation group 1 was treated with vehicle and group 2 was treated with 30 mg./kg. Tadenan daily. Rabbits in groups 3 to 6 underwent partial outlet obstruction surgery. Two weeks after obstruction each rabbit was treated for 3 weeks with vehicle in group 3, and with 1, 10 and 30 mg./kg. Tadenan in groups 4, 5 and 6, respectively. After the completion of treatment cystometry was performed on each rabbit and isolated bladder strips were evaluated for contractile responses to field stimulation, adenosine triphosphate, carbachol and KCl. Separate strips were fixed for electron microscopy to determine the location and severity of cellular and subcellular membrane damage.Partial outlet obstruction resulted in reduced compliance, decreased responses of bladder strips to all forms of stimulation tested, and significant and extensive damage to cellular and subcellular organelle membranes consistent with an ischemia-reperfusion etiology. Daily 1 and 10 mg./kg. Tadenan treatments had little effect on the obstruction induced increase in bladder weight or the deleterious changes in bladder function and structure. However, treating obstructed rabbits with 30 mg./kg. Tadenan daily resulted in reduced bladder hypertrophy, improved compliance, improved contractile responses to nearly normal levels of isolated bladder strips to all stimuli tested and reversal of obstruction induced structural damage to cellular and subcellular organelle membranes.Tadenan treatment of obstructed rabbits resulted in a dose dependent improvement in bladder ultrastructure in parallel with improved bladder compliance and contractile responses of isolated strips to stimulation, providing support for the hypothesis that damage to cellular and subcellular organelle membranes mediates the contractile dysfunction induced by partial outlet obstruction.
View details for Web of Science ID 000174963900089
View details for PubMedID 11956488
To understand the relationship between contractile and structural changes in the obstructed bladder, rabbit bladder was partially obstructed for up to 70 days and alterations in tension response to field stimulation and carbachol were compared with alterations in ultrastructure and innervation of detrusor smooth muscle (SM). The effect of partial outlet obstruction on the physiological responses to field stimulation (FS) (nerve mediated contraction) and carbachol (receptor mediated contraction) were correlated with the structure and innervation of the detrusor smooth muscle (SM) of the same animal during a 70 day period.28 rabbits were subjected to 1 to 70 days of mild partial outlet obstruction. Sham operated rabbits were euthanized at 7, 14, 28, and 70 days post-obstruction. At each time period, isolated strips of bladder body were mounted in individual baths and the contractile response to FS and carbachol determined. Three additional strips from each bladder were fixed for electron microscopy.Bladder mass increased rapidly during the first 7 days after obstruction, was constant for the next 7 days, and then continued to increase gradually. Dysfunction of the contractile response to FS was noted as early as 3 days and progressively increased over the 70-day study period. The decrease in the response to FS increased at a significantly faster rate than the decrease in the contractile response to carbachol. In ultrastructure studies, at 3 and 7 days post-obstruction the majority of SM cells displayed the characteristics of hypertrophy. At 28 days some SM cells displayed loosely packed myofilaments and an irregular distribution of sarcoplasmic dense bodies. At 70 days swollen mitochondria were present in all cell types of the bladder wall. Evidence of axonal degeneration was first observed at 7 days post-obstruction and became more extensive thereafter. No evidence of mitotic figures, nerve growth cones or regenerating SM cells was observed.Prolonged partial bladder outflow obstruction is accompanied by a progressive decrease in contractility of SM. The present study describes the structural damage that occurs in the bladder wall in response to partial outlet obstruction and correlates these observations with the contractile dysfunction with which it is associated. Furthermore, mitochondrial damage in vessels and fibroblasts is suggestive of bladder wall ischemia.
View details for Web of Science ID 000085974000089
View details for PubMedID 10737542
Because doubt still remains concerning the distribution of nerves that are unequivocally cholinergic in the human genitourinary organs, we have used a specific marker, namely, an antibody to vesicular acetylcholine transporter (VAChT), to immunolabel cholinergic axons and cell bodies in specimens of urinary bladder, seminal vesicle, vas deferens, and prostate gland obtained from neonates and children post mortem. In addition some sections were double-immunolabeled with VAChT and either neuropeptide Y (NPY) or nitric oxide synthase (NOS). The results demonstrated a rich cholinergic innervation to the muscle coat of the bladder body with a much less prominent, but nonetheless significant, cholinergic innervation to the smooth muscle components of the seminal vesicle, vas deferens, and prostate. Small ganglia were scattered throughout the detrusor muscle of the urinary bladder, approximately 75% of the intramural neurons being VAChT immunoreactive, whereas approximately 95% contained NPY and approximately 40% contained NOS. VAChT immunoreactivity was observed in 40% of neurons in ganglia scattered throughout the pelvic plexus. Almost all these cholinergic neurons contained NPY and approximately 65% contained NOS. Almost all the cholinergic nerve fibers throughout the genitourinary organs also contained NPY. Although NOS was sparse in the cholinergic nerves of the bladder body, it occurred in the majority of cholinergic nerves at the bladder neck and was also present in a proportion of the cholinergic nerves in the other organs examined. VAChT-immunoreactive nerves were also observed in a sub-epithelial location in all the organs examined, the majority containing NPY, whereas a small proportion contained NOS. Although doubt remains about the function of sub-epithelial cholinergic nerves in the urinary bladder, the majority of similar nerves in the seminal vesicle, vas deferens, and prostate gland are considered to be secretomotor. Collectively these findings demonstrate that the cholinergic innervation of the male genitourinary system is well established in the neonate and child. Neurourol. Urodynam. 19:185-194, 2000.
View details for Web of Science ID 000085548800009
View details for PubMedID 10679835
Autonomic ganglia of the human pelvic plexus contain sympathetic and parasympathetic neurons which innervate the internal reproductive organs and the lower urinary tract while the urinary bladder also receives innervation from small intramural ganglia embedded in the detrusor muscle. Previous studies have used the immunocytochemical demonstration of tyrosine hydroxylase (TH), either alone or in combination with dopamine beta-hydroxylase, to identify noradrenergic neurons in these ganglia. However until recently a reliable marker for cholinergic neurons in the human autonomic nervous system was not available since antibodies to choline acetyltransferase do not react in this tissue. The present immunohistochemical study has used an antibody to human vesicular acetylcholine transporter (VAChT) to identify cholinergic neurons in the pelvic plexus and intramural bladder ganglia in a series of specimens from human male neonates and children. Immunostaining for TH was also carried out on the same sections and the results showed that while the vast majority of pelvic ganglion neurons were either cholinergic or noradrenergic (as seen by the presence of VAChT or TH respectively), approximately 50% of the neurons in the intramural ganglia were labeled with both immunomarkers. The presence of TH in cholinergic neurons may be due to the immaturity of the tissues examined since previous data on intramural bladder ganglia in the adult have shown that a much smaller proportion of the neurons contain TH than was observed in the present study. It is concluded that the presence of TH alone cannot be regarded as a specific marker for noradrenergic neurons in the genitourinary system of the human neonate and child.
View details for Web of Science ID 000084405400005
View details for PubMedID 10626837
The purpose of this presentation is to describe the distribution of noradrenergic nerves in the human genitourinary system. The techniques which have been employed include formaldehyde-induced fluorescence and immunocytochemical methods to demonstrate dopamine beta-hydroxylase and tyrosine hydroxylase. These methods have been applied to human fetal, neonatal, infant, child and adult tissues removed either at post mortem examination or by surgical excision. The innervation of the fetal urinary bladder is well established by 13 weeks and, as in older specimens, the detrusor receives a sparse noradrenergic nerve supply. In contrast the smooth muscle of the terminal ureter is well supplied by this type of autonomic nerve. An additional incomplete muscle layer has been identified as a nomal component of the terminal ureter which is richly innervated by noradrenergic nerves. In some cases this muscle forms a complete collar which may be responsible for ureteric obstruction. By comparison with the detrusor, bladder neck smooth muscle receives a dense noradrenergic nerve supply particularly in the male. Unlike the detrusor, the structure and innervation of the vas deferens, seminal vesicle and prostate are poorly differentiated in the fetus. In the infant and child, the structure of the intramural smooth muscle of these organs remains immature although a rich noradrenergic nerve supply resembing the adult has been established in the fetus by 30 weeks. In the fetus, autonomic ganglia occur in association with noradrenaline rich paraganglia and surprisingly, with sensory nerve endings resembling pacinian corpuscles. Shortly after birth paraganglia are no longer associated with the autonomic ganglia of the genitourinary system. On the basis of size at least two types of autonomic neuron populate these autonomic ganglia. One type is relatively large and devoid of catecholamines but is closely associated with pericellular noradrenergic nerve fibres. The second type of neuron is small, contains noradrenaline and is arranged in clusters closely related to the capsule of the prostate gland. The significance of these observations will be considered with respect to the neurological control of the genitourinary system.
View details for Web of Science ID 000081388100006
View details for PubMedID 10393469
The objective of this study was to examine the distribution of nitric oxide synthase (NOS) and the catecholamine-synthesizing enzyme tyrosine hydroxylase (TH) in nerve fibers supplying the human neonatal male genitourinary organs.An indirect double label immunofluorescence technique was employed on specimens obtained from infants and children at postmortem examination.Many nerve fibers immunoreactive for both NOS and TH were observed in the muscle coat of the vas deferens and the seminal vesicle, within the fibromuscular stroma of the prostate gland and at the bladder neck, and also formed perivascular plexuses in each of these organs. Double-labeled nerves occurred less frequently in the intramural ureters and superficial trigone while similar nerves in the bladder body were relatively sparse. Numerous nerves immunoreactive for NOS but not TH were observed at the base of the epithelium of each organ examined. Four types of autonomic ganglion cell were observed in nearby pelvic ganglia: those which contained NOS and TH, those which contained NOS alone, those which contained TH alone and those which contained neither NOS nor TH.The results indicate that many of the noradrenergic nerves as well as non-noradrenergic nerves supplying the male genitourinary organs have the capacity to synthesize nitric oxide (NO) and that NO may play a significant role in the autonomic control of both the urinary and genital organs in the postnatal human male.
View details for Web of Science ID A1996TU66800090
View details for PubMedID 8583576
To use immunohistochemical methods to study the developing autonomic innervation of the human fetal vas deferens and seminal vesicle.Thirteen pre-natal specimens ranging in gestational age from 13 to 30 weeks were acquired following abortion or miscarriage. The overall innervation of each specimen was visualized using protein gene product 9.5 (PGP), a general nerve marker, while the onset and development of specific neuropeptide-containing sub-populations were investigated using antisera to neuropeptide Y (NPY), vasoactive intestinal peptide (VIP), substance P (SP), calcitonin gene related peptide (CGRP), bombesin (BOM), somatostatin (SOM), and met-enkephalin (ENK). In addition the occurrence and distribution of presumptive noradrenergic nerves was studied using antisera to dopamine-beta-hydroxylase (D beta H) and tyrosine hydroxylase (TH).At 13 weeks numerous PGP, D beta H, TH, NPY and ENK immunoreactive (-IR) nerve trunks were present in the adventitia of the vas deferens and seminal vesicle but at this stage nerve fibres were not present in the smooth muscle coat of either organ. By 17 weeks, fine PGP-, D beta H, and TH-IR nerve fibres had penetrated the outer aspect of the muscle coat of the seminal vesicle but not the vas deferens. At 20 weeks a branching network of PGP-, D beta H- and TH-IR nerve fibres occurred throughout the full thickness of the muscle coat of the seminal vesicle while similar nerves were present only in the outer half of the muscle coat of the vas deferens. At 23 weeks the full thickness of the muscle coat of the vas deferens was richly innervated by a branching plexus of PGP-IR nerves. Many of these adventitial and intramuscular nerves were immunoreactive for D beta H or TH while some were immunoreactive for either NPY or ENK. Occasional adventitial nerves were immunoreactive for SP or CGRP, these being first observed at 20 weeks. VIP-IR nerves were extremely rare in the muscle coat of either organ, being first observed at 17 weeks in the seminal vesicle and at 20 weeks in the vas deferens where they mainly formed perivascular plexuses. PGP-IR nerves were first observed in the submucosa of the seminal vesicle at 20 weeks and in the vas deferens at 21 weeks. Some of these nerves were perivascular in location while other formed a subepithelial plexus which increased in density with increasing gestational age. At 22 weeks of gestation some of the submucosal nerves were immunoreactive for SP or NPY, while at 30 weeks NPY-IR nerves formed the majority of subepithelial nerves. Occasional VIP-IR subepithelial nerves were first observed at 26 weeks but were extremely rare even at 30 weeks. Submucosal nerves immunoreactive for CGRP, D beta H, TH or ENK did not occur in any of the specimens examined.(i) From 13 weeks gestation autonomic nerves develop in the muscle coat of the fetal seminal vesicle and vas deferens, being denser in the seminal vesicle than the vas deferens up to 23 weeks gestation. (ii) The majority of the intramuscular nerves in either organ contain D beta H, TH, NPY and ENK and are presumably noradrenergic in type. (iii) A subepithelial nerve plexus develops around 20 weeks gestation and contains NPY but not VIP, unlike the adult organs. (iv) Scattered neuroendocrine cells immunoreactive for SOM are present in the mucosa of the seminal vesicle from 23 weeks of gestation.
View details for Web of Science ID A1995QL53300020
View details for PubMedID 7735805
To use immunohistochemical techniques to determine the spatial and temporal distribution of a variety of neuropeptides in the human fetal and neonatal urinary bladder.Thirteen pre-natal specimens ranging in gestational age from 17 to 35 weeks were acquired following abortion or miscarriage. In addition two post-natal specimens aged 8 and 12 weeks were obtained at post-mortem and were included in this study. The overall innervation of each specimen was visualized using the general nerve marker protein gene product 9.5 (PGP). Localization of dopamine-beta-hydroxylase (DBH) and tyrosine hydroxylase (TH) revealed putative noradrenergic nerves. The neuropeptides studied included neuropeptide Y (NPY), vasoactive intestinal polypeptide (VIP), substance P (SP), and calcitonin gene-related peptide (CGRP).At 17 weeks a rich plexus of PGP and NPY-containing nerves was present throughout the detrusor muscle coat. As gestational age increased, VIP, SP and CGRP-containing nerves were observed with increasing frequency although SP and CGRP were mainly confined to perivascular nerve plexuses. TH- and DBH-containing nerves were first observed in the intramural ureters at 30 weeks and the detrusor muscle at 35 weeks and were relatively numerous in the intramural ureters and muscle of the superficial trigone in the two post-natal specimens. PGP-containing nerves were first observed beneath the bladder epithelium at 23 weeks and gradually became more numerous with increasing age. Occasional NPY, VIP, SP and CGRP-containing nerves were observed in the submucosa but TH- and DBH-immunostained nerves were especially numerous in the mucosa of the trigone in the two post-natal specimens, many such nerves being unrelated to the vascular supply.The bladder detrusor possesses a rich autonomic innervation by 17 weeks of gestation and this presumptive cholinergic innervation is associated with NPY immunoreactivity. Presumptive noradrenergic nerves appear relatively late in pre-natal development and mainly supply the intramural ureters and superficial trigone. A submucosal plexus of nerves has been demonstrated, the functional significance of which remains uncertain.
View details for Web of Science ID A1995QE96100023
View details for PubMedID 7531592
A quantitative histological study was performed on specimens of 33 ureters obtained from 14 male and 19 female patients 5 days to 14 years old (mean age 1.2 years). A high resolution color image video analysis system was used to quantify and compare collagen and smooth muscle components of the muscularis layers to normal control ureters from patients of similar ages. In comparing ureters with ectopia (7), ureters with ectopic ureteroceles (20) and control ureters (4) there was not a statistically different collagen-to-smooth muscle ratio among the groups. In the patients with posterior urethral valves the amount of collagen and smooth muscle was not statistically different from controls (p > 0.01), although the collagen-to-smooth muscle ratio was increased. The 4 patients with the prune belly syndrome had a collagen-to-smooth muscle ratio that was markedly elevated (1.21 versus 0.39) compared with controls. When this group was analyzed as 2 separate groups (obstructed versus refluxing ureters) the difference was more apparent (p < 0.004). Ureters with ectopia or ectopic ureteroceles and ureters associated with posterior urethral valves had similar quantitative amounts of smooth muscle (60%, 56% and 52%, respectively). In patients with the prune belly syndrome obstructed ureters had 65% muscle and refluxing ureters had 38% muscle on evaluation. The percentage of collagen was 33% in ureters with ectopia, 37% in those with ureteroceles and 48% in those associated with posterior urethral valves compared with 23% in controls. In the group with the prune belly syndrome there was 30% collagen in obstructed ureters and 62% collagen in refluxing ureters. Our findings demonstrate that while these dilated ureters had different etiologies the overall quantitative composition of collagen-to-smooth muscle ratios was similar except in refluxing ureters associated with the prune belly syndrome. Our study provides further insight into the pathological nature of such ureters and considerations for surgical repair.
View details for Web of Science ID A1995PW16700071
View details for PubMedID 7966764
A quantitative histological study of the dilated ureter of childhood was performed on 26 ureters. The specimens were from 15 male and 11 female patients 10 days to 12 years old (mean age 2.0 years). A color image analysis system was used to examine and compare collagen and smooth muscle components of the muscularis layers to normal control ureters of similar age. In comparing primary obstructed (12) to primary refluxing (14) megaureters and control ureters (6), there was a statistically different collagen-to-smooth muscle ratio (p < 0.001) between the primary obstructed and primary refluxing megaureter groups. For patients with primary refluxing megaureter there was a 2-fold increase in the tissue matrix ratio of collagen-to-smooth muscle when compared to patients with primary obstructed megaureter. In the primary obstructed megaureters the amount of collagen and smooth muscle was not statistically different from controls (p > 0.01). The increased tissue matrix ratio of 2.0 +/- 0.35 (collagen-to-smooth muscle) in the refluxing megaureter group compared to 0.78 +/- 0.22 in the obstructed megaureter group and 0.52 +/- 0.12 in controls was found to be due not only to a marked increase in collagen but also a significant decrease in the smooth muscle component of the tissue. Primary obstructed and normal control ureters had similar quantitative amounts of smooth muscle with 60 +/- 5% and 61 +/- 6%, respectively, while refluxing megaureters had only 40 +/- 5% smooth muscle. The percentage collagen was 36 +/- 5 in the obstructed megaureter group and 30 +/- 5 in controls, with refluxing megaureters having 58 +/- 5% collagen on analysis. Our findings emphasize the significant differences in the structural components (collagen and smooth muscle) of the dilated ureter of childhood, and provide us with further insight into the pathological nature of these dilated ureters and their surgical repair.
View details for Web of Science ID A1992JW46000036
View details for PubMedID 1433552
Temporal and distributive properties of ureteral peristaltic contractions in the anesthetized pig have been examined. Interperistaltic time intervals have been recorded, and their frequency during different urine flow rates has been compared. The results show that ureteral peristalsis is increased at high urine flow rates to a maximum of approximately 0.06 Hz. It is further shown from the interperistaltic histograms that ureteral contractions are not clustered into a discreet multimodal spectrum. This represents the first evidence that the multicalyceal kidney has a system of pacemakers of differing fundamental frequencies, tending toward synchronism as urine flow increases.
View details for Web of Science ID A1977DH99500008
View details for PubMedID 870443