Noshir F. Dabhoiwala

Lack of specificity of commercially available antisera against muscarinergic and adrenergic receptors

Commercially available antisera against five subtypes of muscarinic receptors and nine subtypes of adrenoceptors showed highly distinct immunohistochemical staining patterns in rat ureter and stomach. However, using the M1–4 muscarinic receptor subtypes and α2B-, β2-, and β3-adrenoceptors as examples, Western blots with membranes prepared from cell lines stably expressing various subtypes of muscarinic receptors or adrenoceptors revealed that each of the antisera recognized a set of proteins that differed between the cell lines used but lacked specificity for the claimed target receptor. We propose that receptor antibodies need better validation before they can reliably be used.

Causes of fecal and urinary incontinence after total mesorectal excision for rectal cancer based on cadaveric surgery: a study from the Cooperative Clinical Investigators of the Dutch total mesorectal excision trial

PURPOSEnTotal mesorectal excision (TME) for rectal cancer may result in anorectal and urogenital dysfunction. We aimed to study possible nerve disruption during TME and its consequences for functional outcome. Because the levator ani muscle plays an important role in both urinary and fecal continence, an explanation could be peroperative damage of the nerve supply to the levator ani muscle.nnnMETHODSnTME was performed on cadaver pelves. Subsequently, the anatomy of the pelvic floor innervation and its relation to the pelvic autonomic innervation and the mesorectum were studied. Additionally, data from the Dutch TME trial were analyzed to relate anorectal and urinary dysfunction to possible nerve damage during TME procedure.nnnRESULTSnCadaver TME surgery demonstrated that, especially in low tumors, the pelvic floor innervation can be damaged. Furthermore, the origin of the levator ani nerve was located in close proximity of the origin of the pelvic splanchnic nerves. Analysis of the TME trial data showed that newly developed urinary and fecal incontinence was present in 33.7% and 38.8% of patients, respectively. Both types of incontinence were significantly associated with each other (P = .027). Low anastomosis was significantly associated with urinary incontinence (P = .049). One third of the patients with newly developed urinary and fecal incontinence also reported difficulty in bladder emptying, for which excessive perioperative blood loss was a significant risk factor.nnnCONCLUSIONnPerioperative damage to the pelvic floor innervation could contribute to fecal and urinary incontinence after TME, especially in case of a low anastomosis or damage to the pelvic splanchnic nerves.

Lack of Specificity of Commercially Available Antisera: Better Specifications Needed

The ideal antiserum for immunohistochemical (IHC) applications contains mono-specific high-affinity antibodies with little nonspecific adherence to sections. Many commercially available antibodies are “affinity” purified, but it is unknown if they meet “hard” specificity criteria, such as absence of staining in tissues genetically deficient for the antigen or a staining pattern that is identical to that of an antibody raised against a different epitope on the same protein. Reviewers, therefore, often require additional characterization. Although the affinity-purified antibodies used in our study on the distribution of muscarinic receptors produced selective staining patterns on sections, few passed the preabsorption test, and none produced bands of the anticipated size on Western blots. More importantly, none showed a difference in staining pattern on sections or Western blots between wild-type and knockout mice. Because these antibodies were used in most studies published thus far, our findings cast doubts on the validity of the extant body of morphological knowledge of the whole family of muscarinic receptors. We formulate requirements that antibody-specification data sheets should meet and propose that journals for which IHC is a core technique facilitate consumer rating of antibodies. “Certified” antibodies could avoid fruitless and costly validation assays and should become the standard of commercial suppliers.

The anatomical components of urinary continence

BACKGROUNDnThe levator ani muscle (LAM) plays an important role in urinary continence, but the anatomical relationship between this pelvic floor muscle and the external urethral sphincter (EUS) remains incompletely understood.nnnOBJECTIVEnTo investigate the topographical relationship between the EUS and the LAM.nnnDESIGN, SETTING, AND PARTICIPANTSnSerially sectioned and histochemically stained foetal pelves from eleven females and nine males (10-27 wk of gestation) were studied. Three foetal pelves (two female, 12 and 18 wk of gestation; one male, 12 wk of gestation) and three adult pelves (two females, 54 and 85 yr; one male, 75 yr) were stained immunohistochemically for the presence of striated and smooth muscle tissue. Three-dimensional reconstructions were prepared.nnnMEASUREMENTSnAnatomy of the LAM and urethral sphincter components was evaluated qualitatively.nnnRESULTS AND LIMITATIONSnThe EUS has no direct bony attachment. In female foetuses, the inferior part of the EUS is firmly attached to the LAM by a tendinous connection. Contraction of this part of the EUS produces a force on the urethra in a posteroinferior direction. Contraction of the LAM compresses the rectum and moves the rectovaginal complex anteriorly and superiorly towards the urethra in a plane that lies parallel to, but superior of, that of the EUS. Simultaneous contraction of the LAM and EUS causes an anteriorly convex bend in the midurethra, which closes the midurethral lumen. A similar attachment of the EUS to the LAM is absent in the male. Our study is limited due to the absence of young adult study specimens.nnnCONCLUSIONSnThe EUS in females is anchored to the levator ani muscle via a tendinous connection. Because of this attachment to the LAM, proper function of the EUS is dependent on the integrity of the LAM and its attachment to the pelvic wall.

Innervation of the pelvic floor muscles : A reappraisal for the levator ani nerve

OBJECTIVE: We investigated the clinical anatomy of the levator ani nerve and its topographical relationship with the pudendal nerve. METHODS: Ten female pelves were dissected and a pudendal nerve blockade was simulated. The course of the levator ani nerve and pudendal nerve was described quantitatively. The anatomical data were verified using (immuno-)histochemically stained sections of human fetal pelves. RESULTS: The levator ani nerve approaches the pelvic-floor muscles on their visceral side. Near the ischial spine, the levator ani nerve and the pudendal nerve lie above and below the levator ani muscle, respectively, at a distance of approximately 6 mm from each other. The median distance between the levator ani nerve and the point of entry of the pudendal blockade needle into the levator ani muscle was only 5 mm. CONCLUSION: The levator ani nerve and the pudendal nerve are so close at the level of the ischial spine that a transvaginal “pudendal nerve blockade” would, in all probability, block both nerves simultaneously. The clinical anatomy of the levator ani nerve is such that it is prone to damage during complicated vaginal childbirth and surgical interventions. LEVEL OF EVIDENCE: II-3

Functional anatomy of the human ureterovesical junction

The valve function of the ureterovesical‐junction (UVJ) is responsible for protection of the low pressure upper urinary tract from the refluxing of urine from the bladder. Controversy about the microanatomy of the human ureterovesical‐junction persists.

Anatomy and Histology of the Lower Urinary Tract

The function of the lower urinary tract is basically storage of urine in the bladder and the at-will periodic evacuation of the stored urine. Urinary incontinence is one of the most common lower urinary tract disorders in adults, but especially in the elderly female. The urethra, its sphincters, and the pelvic floor are key structures in the achievement of continence, but their basic anatomy is little known and, to some extent, still incompletely understood. Because questions with respect to continence arise from human morbidity, but are often investigated in rodent animal models, we present findings in human and rodent anatomy and histology. Differences between males and females in the role that the pelvic floor plays in the maintenance of continence are described. Furthermore, we briefly describe the embryologic origin of ureters, bladder, and urethra, because the developmental origin of structures such as the vesicoureteral junction, the bladder trigone, and the penile urethra are often invoked to explain (clinical) observations. As the human pelvic floor has acquired features in evolution that are typical for a species with bipedal movement, we also compare the pelvic floor of humans with that of rodents to better understand the rodent (or any other quadruped, for that matter) as an experimental model species. The general conclusion is that the Bauplan is well conserved, even though its common features are sometimes difficult to discern.

Treatment of localized prostatic carcinoma using the transrectal ultrasound guided transperineal implantation technique

Treatment of localized prostate cancer by ultrasonically guided transperineal 125I implantation, in contrast to open 125I implantation, may allow for ideal distribution of the seeds and may therefore lead to better treatment results. 46 patients with localized prostatic carcinoma (T1-T2, G1-G3, N0, M0) have been treated since 1985, using this new technique. The longest follow-up is 64 months (median 30 months). The irradiation implantation dose to the prostate was 160 Gy. Assessed by ultrasonography an average prostate volume reduction of 20% was achieved at 6 months, increasing to 24% at 12 months, 39% at 24 months and 56% at 48 months. To evaluate response of the primary tumor systematic ultrasonically guided needle biopsies from the previous malignant prostate areas were performed in all patients every 6 months during follow-up. Tumor-negative biopsies were obtained in 33% of patients at 12 months, 40% at 24 months, progressively increasing to 50% at 48 months. Three patients developed distant metastases, and 6 died, of whom 1 patient due to prostate cancer. Morbidity from implantation has been low and the erectile function was preserved in all patients at 12 months postimplantation. The high percentage of tumor-positive biopsies during follow-up indicates that this technique fails to cure a significant proportion of patients.

AN IN VIVO ENDOLUMINAL ULTRASONOGRAPHIC STUDY OF PERISTALTIC ACTIVITY IN THE DISTAL PORCINE URETER

PURPOSEnExperiments were performed to quantify the duration and frequency of ureteric peristaltic activity in the laparotomized and non-laparotomized pig in its virgin and postinstrumented states.nnnMATERIALS AND METHODSnPigs (n = 10) in a steady state of hydration were studied under halothane anesthesia in two groups. The study was undertaken in two separate sessions at a weeks interval. In group I laparotomy and vesicotomy were undertaken to obtain ELUS images. In group II, peristalsis was studied using an ELUS probe introduced through the working channel of a 22F rigid cystoscope. Peristalsis was visualized as a periodic diameter-change of ureter and recorded (for approx. 30 minutes) on videotape after an initial period of adaptation of approx. 30 minutes.nnnRESULTSnThe ureter acts like a pump discharging urine into the bladder through peristaltic activity. ELUS imaging of ureteric peristalsis correlated well with eyeballing of the passage of peristalsis through a ureter (group I). The shortest peristaltic activity in group I was 6.0+/-2.0 seconds in the non-instrumented- and 5.1+/-1.4 seconds in the instrumented ureter. In group II it was 6.8+/-1.5 seconds in the non-instrumented- and 6.4+/-1.5 seconds in the instrumented ureter. Chronic dilatation of ureter led to decrease in peristalsis frequency. Interestingly, acute dilatation caused an increase in ureteric peristalsis frequency.nnnCONCLUSIONSnUreteric peristalsis acts as a pump discharging urinary boluses (intraluminal fluid load) unidirectionally into the bladder. ELUS provides us an opportunity to quantify and study ureteric peristalsis.

Intraluminal pressure changes in vivo in the middle and distal pig ureter during propagation of a peristaltic wave

OBJECTIVESnTo establish the characteristics of mechanical activity during ureteral peristalsis and unidirectional bolus transport, pressure changes in the middle and distal (juxtavesical and ureterovesical junction) porcine ureter were quantified in vivo.nnnMETHODSnFive female New Yorkshire pigs (50 to 60 kg) were studied under halothane anesthesia. The endoscopic approach was used to position an 8-channel 6 F perfusion catheter under direct vision into the distal ureter by way of the orifice. Ureteral activity was studied in two separate sessions at 1-week intervals. The pressure, propagation velocity, and length of the peristaltic waves were analyzed.nnnRESULTSnThe average maximal pressure in a not previously instrumented ureter amounted to 35.7 +/- 1.2 cm H(2)O in the mid-ureter, and decreased to 19.4 +/- 1.3 cm H(2)O in the juxtavesical ureter (P < 0.001) and further to 7.2 +/- 1.0 cm H(2)O (P < 0.001) in the submucosal segment. The propagation velocity of the peristaltic wave through the ureter was 2.1 +/- 1.3 cm/s. The length of the pressure peak was 5.9 +/- 1.6 cm.nnnCONCLUSIONSnA ureteral peristaltic contraction wave travels at approximately 2 cm/s and is approximately 6 cm long. It is responsible for the unidirectional transport of a urinary bolus and itself acts as an active antireflux mechanism. The maximal pressure in the lumen of the ureter decreased from proximally to distally, but remains sufficiently high at the ureterovesical junction to prevent retrograde urine leakage when the ureter empties its urinary bolus into the bladder and the orifice is open.