A key role of the basal ganglia in pain and analgesia--insights gained through human functional imaging

The basal ganglia (BG) are composed of several nuclei involved in neural processing related to the execution of motor, cognitive and emotional activities. Preclinical and clinical data have implicated a role for these structures in pain processing. Recently neuroimaging has added important information on BG activation in conditions of acute pain, chronic pain and as a result of drug effects. Our current understanding of alterations in cortical and sub-cortical regions in pain suggests that the BG are uniquely involved in thalamo-cortico-BG loops to integrate many aspects of pain. These include the integration of motor, emotional, autonomic and cognitive responses to pain.

A fMRI evaluation of lamotrigine for the treatment of trigeminal neuropathic pain: pilot study

Using functional magnetic resonance imaging (fMRI) methods, we evaluated the effects of lamotrigine vs placebo in a double-blind 1:1 randomized trial. Six patients with neuropathic pain were recruited for the study. All subjects had baseline pain >4/10 on a visual analog scale (VAS) and allodynia to brush as inclusion criteria for the study. Patients underwent two fMRI sessions, with half of the subjects receiving placebo first and half receiving drug first (based on the blinding protocol). Lamotrigine decreased their average pain intensity level from 5.6 to 3.5 on a VAS. All subjects had brush, cold, and heat applied to the affected and mirror-unaffected sides of their face. The results show: 1) in a small cohort, lamotrigine had a significant effect on heat VAS but not on the other stimuli; and 2) contrast analysis of fMRI results for heat stimuli applied to the affected face for lamotrigine vs placebo produced an overall decrease in blood oxygen dependent level signal, suggesting a potential inhibitory effect of the drug on predominantly cortical regions (frontal, parietal, and temporal).

Improved characterization of BOLD responses for evoked sensory stimuli

Pain and somatosensory processing involves an interaction of multiple neuronal networks. One result of these complex interactions is the presence of differential responses across brain regions that may be incompletely modeled by a straightforward application of standard general linear model (GLM) approaches based solely on the applied stimulus. We examined temporal blood oxygenation-level dependent (BOLD) signatures elicited by two stimulation paradigms (brush and heat) providing innocuous and noxious stimuli. Data were acquired from 32 healthy male subjects (2 independent cohorts). Regional time courses and model-free analyses of the first cohort revealed distinct temporal features of the BOLD responses elicited during noxious versus innocuous stimulation. Specifically, a biphasic (dual peak) BOLD signal was observed in response to heat but much less so in response to brush stimuli. This signal was characterized by a stimulus-locked response along with a second peak delayed by approximately 12.5 s. A cross-validation error analysis determined a modified design matrix comprising two explanatory variables (EVs) as a parsimonious means to model the biphasic responses within a GLM framework. One EV was directly derived from the stimulation paradigm (EV1), while the second EV (EV2) was EV1 shifted by 12.5 s. The 2EV GLM analysis enabled a more detailed characterization of the elicited BOLD responses, particularly during pain processing. This was confirmed by application of the model to a second, independent cohort[AU1]. Furthermore, the delayed component of the biphasic response was strongly associated with the noxious heat stimuli, suggesting that this may represent a sensitive fMRI link of pain processing.

Noninvasive mapping of human trigeminal brainstem pathways

The human trigeminal system mediates facial pain and somatosensory processing. The anatomic location of neuronal substrates and axonal pathways of the trigeminal system have previously been characterized with conventional in vitro methods. The present investigation implemented diffusion tensor imaging (DTI) and probabilistic tractography to first segment the peripheral trigeminal circuitry, trigeminal nerve branches (ophthalmic, maxillary, and mandibular nerves), ganglion, and nerve root. Subsequent segmentations involved the spinal trigeminal and trigeminal thalamic tracts, which respectively convey information to the spinal trigeminal nuclei and ventral thalamic regions. This latter procedure also identified 1) spinal thalamic (anterolateral [AL]) system pathways (propagating pain and temperature information from the body), 2) trigeminal lemniscus (TL; touch and face position), and 3) medial lemniscus (ML; touch and limb position). The anatomic location of the identified pain and somatosensory pathways compared well with previous functional findings in the human trigeminal system, as well as the tract position in human histological cross sections. Probabilistic tractography may be a useful method to further comprehend the functional and structural properties of trigeminal and other related systems. Application of DTI to map pain and somatosensory pathways in conjunction with a characterization of function properties of pain and somatosensory processing would further define the systematic changes that occur in trigeminal pathology.

A high voltage programmable ramp generator

In this paper, a ramp generator with programmable slope is presented. It consists of a high voltage step generator, followed by integrator. The capacitor and inductor in the integrator are designed such that they can be varied by a microcontroller. This circuit generates two bipolar ramps with fastest speed <1 ns and provides continuous speed variation from 6 to 30 ns for a ramp of 500 V. This is being developed as a part of automated streak camera for deflection of electron beam.

Diffusion properties of NAA in human corpus callosum as studied with diffusion tensor spectroscopy

In diffusion tensor imaging (DTI) the anisotropic movement of water is exploited to characterize microstructure. One confounding issue of DTI is the presence of intra- and extracellular components contributing to the measured diffusivity. This causes an ambiguity in determining the underlying cause of diffusion properties, particularly the fractional anisotropy (FA). In this study an intracellular constituent, N-acetyl aspartate (NAA), was used to probe intracellular diffusion, while water molecules were used to probe the combined intra- and extracellular diffusion. NAA and water diffusion measurements were made in anterior and medial corpus callosum (CC) regions, which are referred to as R1 and R2, respectively. FA(NAA) was found to be greater than FA(Water) in both CC regions, thus indicating a higher degree of anisotropy within the intracellular space in comparison to the combined intra- and extracellular spaces. A decreasing trend in the FA of NAA and water was observed between R1 and R2, while the radial diffusivity (RD) for both molecules increased. The increase in RD(NAA) is particularly significant, thus explaining the more significant decrease in FA(NAA) between the two regions. It is suggested that diffusion tensor spectroscopy of NAA can potentially be used to further characterize microscopic anatomic organization in white matter.

Diffusion tensor spectroscopy and imaging of the arcuate fasciculus

The arcuate fasciculus (AF) is a fiber pathway in the human brain relevant for language processes and has recently been characterized by means of diffusion tensor tractography. The observations made concerning the left and right hemisphere AF include a characterization of the trajectories and quantification of physical properties such as fractional anisotropy, DTI-based fiber density and volume. However, these observations were based on the diffusion of water, which is not particular to either the intra- or extra-axonal compartments, and thus its usefulness for tissue characterization is limited. If the diffusion properties and in turn the geometric properties of only one tissue compartment can be isolated and characterized, a better microstructural characterization of AF is possible. In this study, water-based diffusion tensor probabilistic mapping was first implemented to segment the AF. Subsequently, diffusion tensor spectroscopic measurements of N-acetyl aspartate (NAA) were performed to measure the intra-axonal specific diffusion in left and right AF. Diffusion properties of NAA, which solely reflect the intra-axonal space, indicated possible leftward asymmetry in axonal diameter, where those of water, which are not compartment-specific, showed laterality to a lesser extent.

Function and connectivity in human primary auditory cortex: a combined fMRI and DTI study at 3 Tesla

Human primary auditory cortex (PAC) is functionally organized in a tonotopic manner. Past studies have used neuroimaging to characterize tonotopic organization in PAC and found similar organization as that described in mammals. In contrast to what is known about PAC in primates and nonprimates, in humans, the structural connectivity within PAC has not been defined. In this study, stroboscopic event-related functional magnetic resonance imaging (fMRI) was utilized to reveal mirror symmetric tonotopic organization consisting of a high-low-high frequency gradient in PAC. Furthermore, diffusion tensor tractography and probabilistic mapping was used to study projection patterns within tonotopic areas. Based on earlier physiological and histological work in nonhuman PAC, we hypothesized the existence of cross-field isofrequency (homotopic) and within-field non-isofrequency (heterotopic)-specific axonal projections in human PAC. The presence of both projections types was found in all subjects. Specifically, the number of diffusion tensor imaging (DTI) reconstructed fibers projecting between high- and low-frequency regions was greater than those fibers projecting between 2 high-frequency areas, the latter of which are located in distinct auditory fields. The fMRI and DTI results indicate that functional and structural properties within early stages of the auditory processing stream are preserved across multiple mammalian species at distinct evolutionary levels.

Hyponatremic seizures after suprapubic catheter placement in 7-year-old child

We report a case of hyponatremic seizures in a 7-year old boy with spina bifida following cystoscopy and suprapubic catheter placement. Immediate postoperative cystogram and pelvic computed tomogram (CT) after the development of seizures demonstrated a fluid collection from the suprapubic catheter site into the anterior abdominal wall. The subsequent reabsorption of free water from the fluid collection, with the contribution of postoperative hypotonic intravenous fluid administration and possible transient inappropriate antidiuretic hormone (ADH) secretion resulted in acute dilutional hyponatremia and consequent seizures. Strategies to prevent hyponatremia in children during urological procedures, with emphasis on the importance of reserving free water as the irrigation fluid are discussed.

The predictive value of diagnostic imaging for histological lesions of the upper poles in duplex systems with ureteroceles

OBJECTIVE

To compare the diagnostic imaging findings with the histological lesions in upper pole nephrectomy (UPN) specimens of duplex system ureteroceles, using renal ultrasonography (US) and nuclear renal scintigraphy.

PATIENTS AND METHODS

Between 1992 and 2000, 86 patients with a ureterocele in a duplex system underwent surgery. The results from US were reviewed in 84 patients by a radiologist, for echogenicity, parenchymal thinning and hydronephrosis; 77 nuclear renal scans describing the differential function of the upper poles were also reviewed. Fifty-five patients underwent UPN (25 antenatal, 30 postnatal; 18 intravesical, 37 extravesical) and the specimens were available for independent review by a pathologist, describing five histological categories, i.e. chronic interstitial inflammation, fibrosis, tubular atrophy, glomerulosclerosis and dysplasia. Histological lesions were categorized as severe (> 25%) or minimal (<or= 25%). Radiological features and the histology of UPN were then analysed, and correlated using Fisher's exact test and multivariate analysis.

RESULTS

Severe histological lesions were reported in 38 specimens (69%) and minimal lesions in 17 UPN specimens (31%). Severe parenchymal thinning was associated with a severe pathological lesion (P < 0.02). There was no correlation with the echogenicity or degree of hydronephrosis. Dysplasia, found in 64% of specimens, did not correlate with increased echogenicity. Minimally functioning upper poles on nuclear renal scan (<or= 4% overall function) were significantly associated with severe histological lesions (P = 0.01). There was no correlation between diagnostic imaging features and the mode of presentation or type of ureterocele.

CONCLUSIONS

Multivariate analysis, severe parenchymal thinning on renal US and minimal function on nuclear renal scan can be used to predict the severity of histological lesions of the upper pole. These results may be helpful in the making therapeutic decisions for patients with ureteroceles in duplex systems.

The use of tolterodine in children after oxybutynin failure

OBJECTIVE

To assess the safety and efficacy of tolterodine tartrate prescribed to children who previously failed to tolerate oxybutynin chloride.

PATIENTS AND METHODS

We reviewed 34 children, followed for>1 year, who were prospectively crossed-over from oxybutynin to tolterodine because of side-effects. The initial diagnosis was dysfunctional voiding in 31 patients. All patients were placed on a behavioural modification protocol. When their symptoms did not improve after 6 months, treatment with an anticholinergic agent was considered. Urodynamic studies were conducted in 20 patients, confirming uninhibited contractions in 19. The remaining 14 patients were empirically started on antimuscarinic or anticholinergic agents. The 34 patients were treated with oxybutynin for a median (range) of 6 (2-84) months. When significant side-effects were reported, they were crossed over to tolterodine. The efficacy of tolterodine was assessed as defined by the International Children's Continence Society, with tolerability assessed and side-effects documented using a questionnaire.

RESULTS

The mean age at the first dose of tolterodine was 8.9 years; the dose was 1 mg twice daily for 12 patients and 2 mg twice daily for 22. The median treatment with tolterodine was 11.5 months, with 20 (59%) patients reporting no side-effects; six described the same but tolerable side-effects as with oxybutynin. Eight patients discontinued tolterodine because of side-effects after a median (range) of 5 (1-11) months. The efficacy of tolterodine was comparable with that of oxybutynin, as reported by the questionnaire and voiding diaries. The reduction in wetting episodes at 1 year was> 90% in 23 (68%), more than half in five and less than half (or failure) in six patients.

CONCLUSION

Tolterodine is tolerated well in children. In this subgroup of patients who could not tolerate oxybutynin, 77% were able to continue tolterodine treatment with no significant side-effects.

Intraoperative, perioperative, and long-term complications of radical prostatectomy

With improved surgical technique and perioperative care, the intraoperative and early postoperative complications of radical prostatectomy have decreased over the last 2 decades. Incontinence and impotence are two of the most significant long-term complications related to this procedure. Although the wide range of incontinence and impotence rates reported has been attributed to multiple factors, including the method of data collection and patient selection, it is apparent that the surgeon's experience is a significant factor, and that lower long-term morbidity can be expected from centers with more experience with radical prostatectomies. The impact of long-term complications, including urinary and sexual dysfunction, on the quality of life may be less than previously reported and should be discussed with patients.

Impact of preoperative serum PSA level from 0 to 10 ng/ml on pathological findings and disease-free survival after radical prostatectomy

BACKGROUND

To determine the impact of various preoperative serum prostate specific antigen (PSA) levels in the range from 0.1 to 10 ng/ml on pathological stage and disease-free survival after radical prostatectomy.

METHODS

We selected a cohort of 585 patients who underwent radical prostatectomy between 1991-1996 for clinically localized prostate cancer and presented with preoperative serum PSA levels from 0.1 to 10 ng/ml.

RESULTS

Pathological organ-confined disease was present in 57.6% of patients. The rate of organ-confined disease decreased from an average of 85% for patients with a PSA value < 2 ng/ml, to 46.8% for patients with a PSA value > 7 ng/ml. We found statistically significant correlations between preoperative serum PSA level and overall pathological stage (P = 0.001), pathologically organ-confined disease (P = 0.001), margin positive rates (P = 0.001), extra prostatic extension (P = 0.001), and seminal vesicle invasion (P = 0.001). The overall disease-free survival rate was 87%, with a median follow up of 42.4 months. Disease free survival was significantly better for patients with PSA up to 4 ng/ml (P = 0.005).

CONCLUSIONS

Our data suggests that PSA detection programs should strive to detect prostate cancer in men before the PSA level rises above 7 ng/ml. In addition, since patients with a PSA level < 4 ng/ml had better disease-free survival rates than those with a PSA level between 4.1-10 ng/ml, eliminating an arbitrary cutoff of 4 ng/ml, may lead to improved disease-free survival.

Salvage radical prostatectomy

Although technically challenging, salvage prostatectomy for radiorecurrent prostate cancer is an effective option in carefully selected patients and offers the best chance for cure and long-term survival. Alternatively, cystoprostatectomy may be indicated in some patients who have a small capacity fibrotic bladder or intractable voiding symptoms related to radiation cystitis. Good long-term results can be expected in this patient group; however, exenterative surgery in patients with locally advanced disease is associated with comparably inferior results and should not be advocated. If cystectomy is necessary, orthotopic urinary diversion can be performed safely in young motivated patients who wish to maintain a better quality of life with associated morbidity. Although the higher rate of incontinence and impotence after salvage procedures may detract from the quality of life, the impact of these long-term complications on the patient's overall well-being is less than previously believed, and most patients are satisfied with their treatment outcome and adjust well to the circumstances, accepting some increased degree of morbidity. This observation emphasizes the value of careful preoperative counseling and the discussion of treatment options and outcomes, which also should incorporate quality of life issues.

Massive hematuria in adults with Klippel-Trenaunay syndrome associated with vascular malformation of the bladder

Although hematuria has been reported in children with Klippel-Trenaunay syndrome, it is a rare presentation in the adult population. Two cases of massive hematuria in adults with Klippel-Trenaunay syndrome are reported here. A unique feature was venous malformations of the bladder which were responsible for massive recurrent bleeding in 1 patient. The clinical presentation and management are discussed. Conservative endoscopic and arteriographic control seems to be appropriate as initial management in these patients.

Testicular position in the androgen insensitivity syndrome: implications for the role of androgens in testicular descent

PURPOSE

We compared testicular position with genital phenotype in a clinical series and a literature review of androgen receptor mutations to assess the role of androgens in testicular descent.

MATERIALS AND METHODS

Our clinical reports, the androgen receptor mutations database and selected literature were reviewed. Subjects with a proved androgen receptor mutation were included in our study when a female or ambiguous phenotype was present (Quigley grade 3 to 7) and testicular position was documented. Comparison among groups was done by Fisher's exact or chi-square test.

RESULTS

Of the 7 patients with detailed clinical records 5 had abdominal (bilateral in 4) and 2 had bilateral inguinal testes. Four patients with abdominal testes also had aberrant pelvic ligaments extending medially from the gonads. Including an additional 102 cases identified in the literature, abdominal testes were present in 52% and 3% of those with complete and partial androgen insensitivity, respectively. The incidence of abdominal testes was highest (86%) in patients with a complete female phenotype and no pubic hair (grade 7). It decreased significantly with increasing masculinization and was higher in phenotypic females diagnosed at or after (67%) than in those identified before (22%) puberty. Hernia was associated with inguinal and abdominal testes.

CONCLUSIONS

Testicular position correlates with genital phenotype in patients with androgen receptor mutations, supporting a major role for androgens in testicular descent. Inguinal hernia and abnormal pelvic ligaments in these individuals may partially determine testicular position but to our knowledge the role of androgen receptors, if any, in their development is unknown.

Impact of location and multifocality of positive surgical margins on disease-free survival following radical prostatectomy: a comparison between African-American and white men

OBJECTIVES

Although the rate of positive surgical margins is higher in African-American men (AAM) than in white men (WM), the impact of this difference on survival is not clear. Furthermore, it is unknown whether there are racial differences in the distribution of the positive surgical margins after radical retropubic prostatectomy (RRP). We investigated the differences between AAM and WM in terms of the site and multifocality of the positive surgical margins and their effect on disease-free survival (DFS) following RRP.

METHODS

Between January 1991 and December 1995, 493 patients (288 WM and 205 AAM) were treated with RRP as monotherapy. Positive surgical margins were observed in 179 patients (86 WM and 93 AAM). Patients were divided in two groups: group 1 = WM and group 2 = AAM. The incidence and location of the positive surgical margins and their correlation with DFS were determined and compared.

RESULTS

Overall, AAM had a higher rate of positive surgical margins than WM (48% versus 33%, respectively, P = 0.001). There was no significant difference in the frequency of multifocality of the positive margins (P = 0.4). Positive surgical margins were located significantly more often at the base in AAM (P = 0.015); however, the location of the positive surgical margins did not impact on DFS between groups. In those with multifocal positive surgical margins, AAM had a worse DFS compared with WM (P = 0.03).

CONCLUSIONS

Race is an independent prognostic factor for DFS in patients with positive surgical margins. There were no differences in DFS between WM and AAM based on the margin location. In WM, prognostic factors for DFS in those with positive surgical margins were preoperative serum prostate-specific antigen, Gleason score, and pathologic stage. Conversely, in AAM none of these parameters were significant predictors of failure.

Hydro-jet assisted laparoscopic partial nephrectomy: initial experience in a porcine model

PURPOSE

Hemostasis represents a challenge when performing laparoscopic partial nephrectomy. Hydro-Jet cutting is an advanced technology that has been used to create an ultra-coherent water force that functions like a sharp knife. In the surgical field, it has mainly been used for liver surgery and initial clinical experience with laparoscopic cholecystectomies has been favorable. This technique allowed selective parenchymal cutting with preservation of vessels and bile ducts. We describe a novel Hydro-Jet assisted dissection technique for laparoscopic partial nephrectomy in a porcine model.

MATERIALS AND METHODS

Ten partial nephrectomies were performed in 5 pigs using a Muritz 1000 (Euromed Medizintechnik, A. Pein, Schwerin, Germany) Hydro-Jet generator. A thin stream of ultra coherent fluid is forced at a high velocity through a small nozzle. A modified probe allows both blunt dissection concomitantly with high-pressure water application. Coagulation can be applied via a bipolar thermoapplicator as needed.

RESULTS

Laparoscopic partial nephrectomy was successful in all animals. Water-jet cutting through the parenchyma was virtually bloodless and preserved the vasculature and the collecting system. The vessels were then ligated or coagulated under direct vision. The continuous water flow established a bloodless operating field and a clear view for the surgeon. The mean dissection time and warm ischemia time were 45+/-9 and 17+/-3 minutes, respectively.

CONCLUSIONS

This preliminary study supports the suitability of this technique for laparoscopic partial nephrectomy to improve hemostasis. The improved anatomical dissection and hemostasis may further decrease morbidity and operative time. Further studies are underway to compare this technique with laser coagulation for laparoscopic partial nephrectomy.

Surgical complications of bladder augmentation: comparison between various enterocystoplasties in 133 patients

OBJECTIVES

Ileal and sigmoid augmentation are equally effective at increasing bladder capacity and compliance. Therefore, knowledge of the incidence of major complications, including perforation, small bowel obstruction (SBO), anastomotic complications, calculus formation, and indications for revision may be useful in choosing the ideal segment. We compared the complications of ileocystoplasty and two types of sigmoidocystoplasty that required reoperative surgery.

METHODS

Between 1981 and 1997, 158 patients with a mean age of 11 years (range 2 to 25) underwent augmentation cystoplasty. Ileum or sigmoid colon was used in 133 patients, who were the subjects of this study. The mean follow-up was 64 months (range 6 to 185). Indications included neurogenic bladder (n = 100), bladder exstrophy (n = 12), cloacal exstrophy (n = 6), posterior urethral valves (n = 3), and miscellaneous (n = 12). Ileum was used in 65 patients and sigmoid colon in 68. Of these, 48 underwent conventional colocystoplasty and 20 seromuscular colocystoplasty lined with urothelium (SCLU). Seventy-nine percent required additional procedures to achieve continence or facilitate catheterization, which included bladder neck procedures in 56% or continent stomas alone in 23%.

RESULTS

There were no deaths or complications of bowel anastomosis. Overall, continence was achieved in 95%. Spontaneous bladder perforation was highest in patients with neurogenic bladder. Calculi developed more frequently in patients with continent stomas (P = 0.04) and in patients with bladder/cloacal exstrophy (32%) than in patients with neurogenic bladder (P = 0.01). Additional procedures and route of catheterization did not increase the risk of perforation. One patient with SCLU with known hypercalciuria developed bladder calculi.

CONCLUSIONS

Sigmoid colon showed a trend of a lower rate of SBO with no difference in perforation or stone formation compared with ileum. Primary diagnoses of bladder or cloacal exstrophy and continent stomas are risk factors for the development of calculi. SCLU has a low rate of surgical complications and no incidence of perforation or SBO thus far; therefore, we advocate the use of SCLU when feasible, and sigmoid as the preferred bowel segment for augmentation cystoplasty.

Vesicourethral anastomosis biopsy after radical prostatectomy: predictive value of prostate-specific antigen and pathologic stage

OBJECTIVES

To assess the role of clinical parameters and pathologic stage in predicting a positive vesicourethral anastomosis (VUA) biopsy in patients with a rising prostate-specific antigen (PSA) level after radical prostatectomy.

METHODS

Forty-five patients were referred for a rising PSA level after radical prostatectomy. Transrectal ultrasound evaluation included visualization of the VUA and VUA quadrant biopsies. The rate of positive biopsies (per core and per patient) was correlated with race, PSA level, and the radical prostatectomy pathologic stage.

RESULTS

Overall, 53% of patients had a positive biopsy. In multivariate analysis, the dominant independent and synergistic clinical parameters determining positive biopsy rates were a PSA greater than 1 ng/mL at the time of biopsy and the pathologic stage (P = 0.04 and P = 0.02, respectively). Using a PSA cutoff point of 1.0 ng/mL, those patients with organ-confined disease and a PSA of 1.0 ng/mL or less showed no positive cancer cores (low-risk group). Conversely, 89% of patients with extraprostatic extension and a PSA greater than 1.0 ng/mL had a positive biopsy (P <0.01) (high-risk group). Patients with organ-confined disease and a PSA greater than 1.0 ng/mL or extraprostatic extension and a PSA 1.0 ng/mL or less (intermediate-risk group) had a significantly higher chance of having residual cancer than the low-risk group (P <0.025).

CONCLUSIONS

The PSA level at the time of biopsy and the pathologic stage of the radical prostatectomy specimen were the strongest determinants of a positive biopsy. A combination of PSA and pathologic stage is useful for decisions regarding VUA biopsy. Patients with organ-confined disease and a PSA of 1.0 ng/mL or less do not appear to benefit from a VUA biopsy, and patients with extraprostatic extension and a PSA greater than 1.0 ng/mL have such a high probability (89%) of local recurrence at the VUA that biopsy may be unnecessary. It appears that VUA biopsy can be restricted to those patients with an intermediate risk (organ-confined disease with PSA greater than 1 ng/mL or extraprostatic extension with a PSA less than 1 ng/mL).

Membrane type 1-matrix metalloproteinase (MT1-MMP) and MMP-2 immunolocalization in human prostate: change in cellular localization associated with high-grade prostatic intraepithelial neoplasia

Membrane type 1-matrix metalloproteinase (MT1-MMP) is a known activator of latent MMP-2 (pro-MMP-2), and increased MMP-2 expression has been associated with tumor aggressiveness in prostate cancer. However, expression of MT1-MMP in human prostate tissue has not been described. We investigated the expression and immunolocalization of MT1-MMP and MMP-2 in the epithelial components of benign prostate epithelium, high-grade prostatic intraepithelial neoplasia (HGPIN), and prostate cancer. Tissue sections from the peripheral zone of 50 prostates (radical prostatectomy specimens) were chosen based on their containing benign glands, HGPIN, and prostate cancer glands. All 50 sections were immunostained for MT1-MMP and MMP-2 and were evaluated for staining pattern, uniformity, and intensity. Western blotting and gelatin zymography were done to confirm expression of MT1-MMP and activity of MMP-2, respectively. Comparisons were made between benign epithelium, HGPIN, and cancer. In benign glands, basal cells (BCs) uniformly stained intensely for MT1-MMP, whereas secretory cells (SCs) were rarely positive (P < 0.0001). Conversely in HGPIN, SCs showed consistent cytoplasmic staining (P < 0.0001). In cancer cells, staining was heterogeneous and varied from no staining to very intense staining in select glands. MMP-2 in normal tissue stained both BCs and the apical region of SCs, whereas in HGPIN, staining was observed in the SC in a predominantly cytoplasmic pattern. Similar to MT1-MMP, staining in cancer tissue for MMP-2 was heterogeneous; however, there was a significant association between the pattern of MMP-2 and MT1-MMP staining within the epithelial components of the cancer glands in individual specimens (P < 0.001). Finally, MMP-2 and MT1-MMP were confirmed to be expressed in the prostate tissues by gelatin zymography and Western blotting. In conclusion, we found that consistent changes in localization and intracellular distribution of MMP-2 and MT1-MMP were associated with the transition from benign prostate epithelium to HGPIN, suggesting that regulation of these enzymes is altered during the earliest stages of prostate cancer.

Hydro-jet dissection for laparoscopic nephrectomy: a new technique

OBJECTIVES

The Hydro-Jet technique has been used to cut various industrial materials. In the medical field, this technique has been successfully used for selective dissection of the parenchyma of organs such as the liver. Recently, this technique was successfully used for laparoscopic cholecystectomy in humans. We developed a new Hydro-Jet probe and a technique of Hydro-Jet dissection during laparoscopic nephrectomy (LN) in a porcine model and compared the results with those of conventional laparoscopy.

METHODS

Fourteen pigs underwent unilateral LN using the Hydro-Jet and a conventional LN on the contralateral side. A Muritz 1000 Hydro-Jet generator was used. An adjustable water pressure gauge allowed manual control up to a maximum of 30 atm, and coagulation was applied by way of a bipolar thermoapplicator. The bent end of the probe allowed both blunt dissection and concomitant high-pressure water application. Results were compared with regard to ease of anatomic dissection, complications, and operative time between the two techniques.

RESULTS

LN was successful in all animals with no conversion to open surgery. The dissector allowed anatomic planes to be created in a relatively bloodless field, and continuous water flow allowed a clear view for the operator. The high-pressure stream resulted in excellent dissection of adventitial and soft tissue adjacent to vascular structures, with complete preservation of vessels and ureter for selective ligation. The dissection time was shortened (mean 27 minutes for the Hydro-Jet versus 40 minutes for the conventional technique).

CONCLUSIONS

To our knowledge, we describe the first report of Hydro-Jet dissection for LN as an alternative to the conventional technique. The improved anatomic dissection may decrease complications. Moreover, shorter operating times were achieved, which may result in cost savings. Further studies in humans are necessary to investigate this technique.

Long-term outcome based on the initial surgical approach to ureterocele

PURPOSE

The management of extravesical ureterocele is controversial. Heminephrectomy and recently recommended primary incision or puncture have high reoperation rates. We reviewed and compared the long-term results of these procedures with those of primary lower tract reconstruction for ureterocele.

MATERIALS AND METHODS

We reviewed the records of 106 children with ureterocele treated between 1979 and 1997. Followup was available in 99 patients, including 72 with extravesical and 27 with intravesical ureterocele. Patients with extravesical ureterocele were divided based on initial management into group 1-13 who underwent transurethral incision or puncture, group 2-41 who underwent an upper tract approach, including partial or complete nephrectomy with partial ureterectomy or ureteroureterostomy and group 3-18 who underwent complete reconstruction, including ureterocelectomy and ureteral reconstruction with or without upper tract surgery.

RESULTS

Overall the reoperation rate in patients with intravesical ureterocele was 22% and 23% in those treated with initial endoscopic incision or puncture. In patients with extravesical ureterocele the reoperation rate was 100, 41 and 0% in groups 1 to 3, respectively. Differences in followup (overall mean 6 years) and the incidence of preoperative reflux in the 3 groups were not statistically significant. In group 2, the reoperation rate in patients with versus without preoperative reflux was 57 versus 20% (p = 0.08). Of the 25 prenatally diagnosed patients urinary tract infection developed preoperatively in 3 (12%) at ages 2, 3, and 6 months, respectively. Mean age at the time of the initial operation in all prenatally diagnosed patients was 3.1 months (range 5 days to 11 months).

CONCLUSIONS

Complete reconstruction appears to be safe and highly effective even in infancy for treating extravesical ureterocele. Although the primary upper tract approach is associated with a significantly higher reoperation rate, it is a favorable alternative in patients with no preoperative reflux. However, while transurethral decompression is effective in the majority of patients with intravesical ureterocele, it is not definitive therapy for extravesical ureterocele and it should have a limited role in initial management.