Circulating adipocyte fatty acid binding protein is increased in chronic and acute renal dysfunction

BACKGROUND AND AIMS

The adipokine adipocyte fatty acid binding protein (AFABP) is positively associated with the development of the metabolic syndrome, diabetes mellitus, and cardiovascular disease. We hypothesized that AFABP also increases with deteriorating renal function.

METHODS AND RESULTS

Serum AFABP levels were quantified by enzyme linked immunosorbent assay in 532 patients with chronic kidney disease (CKD) covering the whole spectrum of estimated glomerular filtration rate (eGFR) categories from G1 to G5 (study population 1). Furthermore, AFABP was measured in 32 patients before and within 30 h after elective unilateral nephrectomy, a model of acute kidney dysfunction (AKD) (study population 2). Moreover, circulating AFABP was investigated in rats undergoing bilateral nephrectomy (BNE) as compared to sham-operated animals. Median serum AFABP levels adjusted for age, gender, and body mass index significantly increased with increasing eGFR category (G1: 22.0 μg/l; G2: 34.6 μg/l; G3: 56.7 μg/l; G4: 95.2 μg/l; and G5: 173.9 μg/l). Furthermore, renal dysfunction remained positively associated with AFABP in multivariate analysis in this cohort. In patients undergoing unilateral nephrectomy, AFABP increased significantly after surgery (42.1 μg/l) as compared to pre-surgical values (29.3 μg/l). Furthermore, relative changes of post-to-pre-surgical AFABP levels were independently associated with relative changes of post-to-pre-surgical creatinine concentrations. After BNE in rats, AFABP increased significantly as compared to sham-operated animals.

CONCLUSIONS

We show that AFABP is significantly elevated in CKD and AKD patients. Furthermore, measures of renal function are associated with circulating AFABP. Moreover, animal experiments indicate that AFABP levels strongly depend on renal function.

Analysis of the pentafecta learning curve for laparoscopic radical prostatectomy

PURPOSE

Laparoscopic radical prostatectomy (LRP) has a long learning curve; however, little is known about the pentafecta learning curve for LRP. We analysed the learning curve for a fellowship trained surgeon with regard to the pentafecta with up to 6-year follow-up.

METHODS

A retrospective review was performed in 550 cases, by dividing these cases into 11 groups of 50 patients. Outcomes analysed were the following: (1) the pentafecta (complication rate, positive surgical margin (PSM) rate, continence, potency and biochemical recurrence); (2) operative time and blood loss; and (3) overall pentafecta attainment.

RESULTS

The mean complication rate for the entire series was 9 %; this plateaued after 150 cases. The overall PSM rate for the series was 23.5 %, 16.3 % for pT2 and 40.5 % for pT3. PSM plateaued after 200 cases. Excluding the first 100 cases, the overall PSM rate for pT2 was 10.9 % and 37.8 % for pT3. The continence rate stabilised after approximately 250 cases. The rate of male sling/artificial urinary sphincter plateaued after 200 cases. The potency learning curve continues to improve after 250 cases of nerve-sparing (ns) endoscopic extraperitoneal radical prostatectomy (EERPE) as does the pentafecta learning curve which closely follows the pattern of the potency learning curve. The last group of nsEERPE achieved pentafecta in 63 %.

CONCLUSION

This study shows multiple learning curves: an initial for peri-operative outcomes, then stabilisation of oncologic outcomes and the final for stabilisation of functional outcomes. In this series over 250 cases were required to achieve the learning curve.

[Sacral neuromodulation in urology - development and current status]

Sacral neuromodulation (SNM) in urology is employed to treat refractory lower urinary tract dysfunction as well as chronic pelvic pain. Electrical stimulation of the sacral afferents (S2 - S4) causes activation and conditioning of higher autonomic and somatic neural structures and thereby influences the efferents controlling the urinary bladder, the rectum and their related sphincter systems. It is therefore possible to treat overactivity as well as hypocontractility and functional bladder neck obstruction. SNM treatment is conducted biphasically. Initially, test electrodes are placed to evaluate changes in micturition and pain parameters. If, in this first phase - called peripheral nerve evaluation (PNE test) - sufficient improvements are observed, the patient progresses to phase two which involves implantation of the permanent electrodes and impulse generator system. In recent years, the "two stage approach" with initial implantation of the permanent electrodes has been favoured as it increases treatment success rates. Long-term success rates of SNM vary significantly in the literature (50 - 80 %) due to heterogeneous patient populations as well as improved surgical approaches. With the introduction of "tined lead electrodes" (2002), tissue damage is reduced to a minimum. Technical innovation, financial feasibility (reimbursed in Germany since 2004) and wider application, especially in otherwise therapy-refractory patients or complex dysfunctions of the pelvis, have established SNM as a potent treatment option in urology.

[New insights in the differential diagnosis of bladder pain syndrome]

The diagnosis of bladder pain syndrome/interstitial cystitis (BPS/IC) is challenging, since pathogenetic mechanisms and the definition of clinical relevant parameters are still under lively discussion. The criteria recently proposed by the European Society for the Study of Interstitial Cystitis (ESSIC) define a collective of patients based on the cardinal symptom of bladder pain which is heterogeneous, and therefore cannot receive standardised consistent therapy. Thus an extended diagnosis based on molecular markers seems to be indicated to render individual pharmacotherapy possible, and to contribute to elucidation of BPS/IC pathogenesis. For this purpose we feel the vital need for taking a bladder biopsy. The diagnosis of BPS/IC should rely on 3 "columns": (1) clinical diagnostics; (2) histopathology; (3) molecular diagnostics/protein expression. Since a significant contribution of the 3 functional units of the bladder to the pathophysiology is most evident, the examinations should ideally include urothelium, lamina propria, and detrusor musculature. Generation of receptor profiles of the detrusor muscle represents a first attempt to define a diagnostic tool for the individualisation of BPS/IC pharmacotherapy. Other factors, e.g., beta-hCG expression in the urothelium, need further evaluation. Extended BPS/IC diagnostics could be realistically integrated into routine patient care within a clinic/laboratory network.

Anxiety and depression in cancer patients compared with the general population

The objective of this study was to compare the prevalence of anxiety and depression in cancer patients with the prevalence found in the general population, using the Hospital Anxiety and Depression Scale (HADS). Participants were 1529 cancer patients treated between 2002 and 2004 in Germany and 2037 persons from the German general population. In the cancer patients, the risk of psychiatric distress was nearly twice that of the general population. While for older age groups (61 years and above) there were only small differences between cancer patients and the general population, the differences in both scales were high for young persons. There were differences between the HADS mean scores of the patients with different tumour localisations, with high values for brain cancer and low scores for prostate cancer. The influence of the tumour stage on anxiety and depression was weak. However, depression scores of patients with a survival time less than 1 year were elevated. The results show that large sample sizes are necessary to evaluate the psychological situation of cancer patients, and that age and gender differences must be taken into account when several samples are compared.

[Myofibroblasts and afferent signalling in the urinary bladder. A concept]

Afferent signal transduction in the urinary bladder is still not clearly understood. An increasing body of evidence supports the view of complex interactions between urothelium, suburothelial myofibroblasts, and sensory nerves. Bladder tissue from tumour patients was used in this study. Methods included confocal immunofluorescence, polymerase chain reaction, calcium imaging, and fluorescence recovery after photobleaching (FRAP).Myofibroblasts express muscarinic and purinergic receptors. They show constitutive spontaneous activity in calcium imaging, which completely depends on extracellular calcium. Stimulation with carbachol and ATP-evoked intracellular calcium transients also depend on extracellular calcium. The intensive coupling between the cells is significantly diminished by incubation with TGF-beta 1. Myofibroblasts form an important cellular element within the afferent signalling of the urinary bladder. They possess all features required to take part in the complex interactions with urothelial cells and sensory nerves. Modulation of their function by cytokines may provide a pathomechanism for bladder dysfunction.

Management of lymph nodes in early prostate cancer

This article is a review of the literature concerning the management of lymph nodes (LNs) in early prostate cancer. The literature review was performed using the PUBMED database. The treatment of LNS in early prostate cancer usually requires a pelvic LN dissection (PLND), which is performed in all patients with localized prostate cancer. Sometimes nomograms are used to select patients requiring lymphadenectomy. No consensus is available concerning the indications for the performance of PLND and the extent of the lymphadenectomy that should be performed. Recent non-surgical methods detecting LN invasion seem promising, but further investigations and a consensus attainment for terminology and investigation methodologies are advisable.

Oncological and functional results of open, robot-assisted and laparoscopic radical prostatectomy: does surgical approach and surgical experience matter?

The treatment of prostate cancer has undergone a fundamental change in the last decade. New surgical and nonsurgical minimal invasive methods have evolved. As the methodology of the different treatments is commonly known to urologists, this article focuses on oncological and functional outcome of open retropubic (ORP), trans- or extraperitoneal endoscopical (LRP), and robot-assisted radical prostatectomy (RALP), based on personal experience and review of the literature. A MEDLINE search was performed to review the literature on LRP and RALP between 1982 and 2007 with special emphasis on oncological and functional results, technical considerations, comparison of LRP and RALP to ORP, laparoscopic training, historical aspects, and cost-efficiency of the techniques. Based on diligent training and proctoring programs, a continuous dissemination of laparoscopic techniques takes place. There is a trend towards the extraperitoneal access in most of the minimal invasive programs at least in the European community. Mid-term outcomes of LRP and short-term outcomes of RALP achieved equivalence to open surgery with regards to complications, oncologic and functional results. Distinct advantages of LRP include less postoperative pain, lower transfusion rates, shorter convalescence, and better cosmetics. In contrast to RALP, LRP reaches cost-equivalence with open surgery in selected centers. LRP and RALP reproduce the short-term results of open surgery while providing the advantages of a minimal access. Video-assisted teaching improves the transfer of anatomical knowledge and technical knowhow, but the discussion about the longer learning curve for laparoscopy handling remains. The future will show if European centers adopt the use of robots comparable to the United States.

[Laparoscopic extraperitoneal radical prostatectomy: changes in time and updated results]

Laparoscopic radical prostatectomy has been established and adopted by specialized urologic centers around the world as the primary approach to the surgical management of localized prostate cancer. Urologists are on a continuous search for development of technical modifications and refinements, to reduce morbidity and ameliorate clinical and quality of life outcome. In 2002 we have initially reported our technique and experience with the totally extraperitoneal endoscopic radical prostatectomy (EERPE). In the present review paper we present the evolution of the technique and the latest results.

Patienten nach Prostatektomie

BACKGROUND

Prostate carcinoma patients (PCP) with mental disorders suffer frequently from a decreased quality of life (QOL) and often need psychooncological treatment (PTN). To meet that need, the extent of treatment required should be determined and a reliable identification routine implemented.

METHODS

A total of 103 PCP were interviewed with a validated instrument (SCID) during urological inpatient treatment to assess mental disorders of PTN, and questionnaires were administered to examine QOL (QLQ-C30) and mental stress (HADS); 17 doctors and 23 nurses assessed their patients' PTN.

RESULTS

Twenty percent of the patients had a PTN which was identified by doctors and nurses in 50% of the cases and by HADS in up to 84%. Even 1 year after treatment, the QOL of patients with PTN was diminished, while patients without recovered remarkably better.

CONCLUSION

Patients with PTN should be detected as a matter of routine, e.g., using the HADS, and treated early.

Repair of inguinal hernias using the mesh technique during extraperitoneal pelvic lymph node dissection

PURPOSE

This article describes our experience of using a totally extraperitoneal approach for endoscopic pelvic lymphadenectomy and inguinal hernia repair with the mesh technique in one procedure.

MATERIALS AND METHODS

A total of 52 patients underwent modified pelvic lymph node dissection for the staging of prostate cancer. Eight of them had hernia defects; 1 was recurrent. Five patients with direct and 3 patients with indirect inguinal hernias were treated by totally extraperitoneal hernia repair with the placement of a mesh measuring at least 10 x 15 cm (prolene mesh with incision and flap).

RESULTS

The mean duration of the lymphadenectomy itself was decreased from 150 min (first 20 patients) to 70 min (n = 21-52). The mean additional procedure time for hernioplasty was 15 min. The overall lymph node-positive rate was 9.6%. The complication rate was 7.7%. Four patients developed symptomatic lymphoceles, 1 of whom developed deep venous thrombosis. No complications occurred which were attributed to hernia repair. Morbidity did not rise, and hospitalization time did not increase for the patients who underwent hernioplasty. There were no recurrences or neuralgias on follow-up up to 2 years.

CONCLUSIONS

By avoiding entry into the peritoneal cavity, the extraperitoneal approach obviates intra-abdominal complications (ileus, bowel injury, peritonitis) in both techniques. The extraperitoneal approach for pelvic lymph node dissection allows concomitant inguinal hernia to be repaired with low morbidity and within an acceptable operating time.

Comparative anatomy of the male guinea-pig and human lower urinary tract: histomorphology and three-dimensional reconstruction

The guinea-pig is often used for experimental studies in urology. However, the anatomy of the lower urinary tract of the guinea-pig is poorly described in the literature. The structure and function of the lower urinary tract, i.e. continence, micturition and sexual function, are closely related to the gross anatomy of the pelvis and the fine structure of the musculature. We investigated the anatomy and histomorphology of the lower urinary tract by serial sections in male guinea-pigs and compared it to that in humans. Immunohistochemical stainings for alpha-smooth muscle cell actin were used to differentiate between smooth and striated muscles. By using whole pelvic preparations, including all internal organs preserved in their in situ location for three-dimensional reconstruction, we developed three-dimensional models, which elucidate the spatial relationship of all muscular structures and can help to deduce functional aspects of lower urinary tract function. In the guinea-pig, most of the muscles found in humans can be demonstrated in comparable location and extension. However, the structure of the prostate and the existence of the so-called coagulation glands define a significant difference in the morphology of the prostatic urethra.

Comparative anatomy of the male guinea-pig and human lower urinary tract: histomorphology and three-dimensional reconstruction

The guinea-pig is often used for experimental studies in urology. However, the anatomy of the lower urinary tract of the guinea-pig is poorly described in the literature. The structure and function of the lower urinary tract, i.e. continence, micturition and sexual function, are closely related to the gross anatomy of the pelvis and the fine structure of the musculature. We investigated the anatomy and histomorphology of the lower urinary tract by serial sections in male guinea-pigs and compared it to that in humans. Immunohistochemical stainings for alpha-smooth muscle cell actin were used to differentiate between smooth and striated muscles. By using whole pelvic preparations, including all internal organs preserved in their in situ location for three-dimensional reconstruction, we developed three-dimensional models, which elucidate the spatial relationship of all muscular structures and can help to deduce functional aspects of lower urinary tract function. In the guinea-pig, most of the muscles found in humans can be demonstrated in comparable location and extension. However, the structure of the prostate and the existence of the so-called coagulation glands define a significant difference in the morphology of the prostatic urethra.

[Anatomic principles of urinary incontinence]

The morphological fundamentals of urinary continence are still subject to controversy. This was the reason for a renewed examination of the sphincter musculature of the lower urinary tract. This study included 50 male and 15 female autopsy specimens. The organs of the lower urinary tract including the neighboring organs had been removed in their entirety and histologically reprocessed en bloc as a complete series of sections. We were able to demonstrate that the internal sphincter or m. sphincter vesicae is represented as a circular, distinct structure which elliptically embraces the internal urethral orifice. Lamellas of the detrusor are not involved in the formation of the internal sphincter. In females and males, the external sphincter consists of a striated and a smooth muscular part (m. sphincter urethrae transversostriatus et glaber). In transverse sections, the muscle has a horseshoe shape. It is completely separated by connective tissue from the musculature of the pelvic floor. A deep transverse perineal muscle does not exist. The histological findings were used for the construction of a digital three-dimensional model of the anatomy of the lower urinary tract. Computer animations of the model with integrated original histologies were generated and stored as a computer video on a CD-ROM attached to this journal.

Efficacy and cardiac safety of propiverine in elderly patients - a double-blind, placebo-controlled clinical study

The study investigated the efficacy and cardiac safety of propiverine in the elderly, because the induction of life-threatening ventricular arrhythmia has been reported for some drugs prescribed in the therapy of urinary incontinence. Ninety-eight patients (21 male, 77 female; 67.7+/-6.3 years of age) suffering from urgency, urge incontinence or mixed urge-stress incontinence were included in the double-blind, multicentre, placebo-controlled, randomized study. After a 2-week placebo run-in period, the patients received propiverine (15 mg t.i.d.) or placebo (t.i.d.) for 4 weeks. Before (V1, V2) and during the treatment period (V3, V4), standard ECGs and 24-hour long-term ECGs were recorded. Propiverine caused a significant reduction of the micturition frequency (V2: 8.7+/-4.2, V4: 6.5+/-3.2 ml; p< or =0.01), reflected in a significant increase in the average micturition volume (V2: 163.5+/-65.9, V4: 216.3+/-101.5 ml; p< or =0.01) and a significant decrease in episodes of incontinence (-54%; p = 0.048). These findings were confirmed by the overall assessment at V4, in which approximately 90% of patients under propiverine either had no urge incontinence or urge symptoms, or showed improvement. Resting and ambulatory electrocardiograms indicated no significant changes. Neither the frequency-corrected Q-T interval nor other cardiac parameters were relevantly altered. The frequency of cardiac events (Lown classes IVa/b) was random, revealing no difference between placebo and propiverine. The incidence of adverse events was very low (2% dryness of the mouth under propiverine) and confirmed by the findings from the quality of life questionnaires. A favourable benefit-risk ratio without the induction of any cardiac arrhythmia in the treatment of elderly patients suffering from urgency, urge incontinence or combined urge-stress incontinence is therefore proven for propiverine.

The dispute about the external sphincter and the urogenital diaphragm

PURPOSE

Basic scientific facts, such as anatomical structures, are rarely subjected to critical reappraisal. Nevertheless, several clinical phenomena exist which are inconsistent with the description of the anatomy of the so-called external sphincter muscle and urogenital diaphragm.

MATERIALS AND METHODS

We performed a global examination of the anatomy of the entire lower urinary tract in 50 male autopsy specimens. For comparison magnetic resonance imaging of the same regions was performed on 12 healthy patients.

RESULTS

Direct comparison of the results of both methods revealed the exact same topography of the bladder neck. The external sphincter or musculus sphincter urethrae is an independent morphological unit separated from the surrounding pelvic floor muscles by connective tissue.

CONCLUSIONS

The musculus transversus perinei profundus or deep transverse perineal muscle, which is believed to constitute the major element of the urogenital diaphragm, does not exist. There is histomorphological evidence that the external sphincter consists of a striated (musculus sphincter urethrae transversostriatus) and smooth muscle (musculus sphincter urethrae glaber) component.

[New methods for transurethral electroresection of the prostate from the anesthesiologic viewpoint]

Intravascular absorption of large volumes of solution without electrolytes is a common problem in transurethral resection of the prostate. In the present study we compared two different methods of resection (TURP vs. Vaporization TURP; 20 patients in each group) regarding fluid absorption and loss of blood. In addition, we report on 60 patients who had Vapo-TURP. The operations were performed by different very experienced surgeons. In both groups, spinal anaesthesia and standard regimes of infusion were used. The amount of fluid absorbed was measured by the ethanol method (2 vol.% ethanol; Widmark-formula). Haemoglobin, haematocrit and electrolytes were determined at set times. Ten of the 20 patients in the TURP group showed blood-alcohol levels > 0.1%/1000. In the Vapo-TURP group, only five of 57 patients (three patients with perforation of the prostate capsula were excluded) showed positive levels of blood-alcohol (< 0.05%/1000; fluid absorption < 150 ml). The difference was statistically significant (p = 0.002). Sixty minutes after the beginning of the procedures, the values of haemoglobin and haematocrit were significantly lower in the TURP group (7.68 +/- 0.41 vs. 7.38 +/- 0.64 mmol/l and 0.36 +/- 0.02 vs. 0.34 +/- 0.03). Regarding absorption of fluid and bleeding, Vapo-TURP was superior. From the anaesthesiological point of view, Vapo-TURP should be the method of choice, especially for the elderly.

The value of DNA cytometry in transitional cell carcinoma of the urinary bladder

Transitional cell carcinomas are tumors with a high tendency of local recurrence. The extent of the primary tumor and histopathologic grade incompletely predict the individual outcome. In several studies, measurement of nuclear DNA content has been found to be of prognostic value in bladder cancer. We performed static DNA cytometry on transitional cell carcinomas of 130 patients. DNA parameters were correlated with stage and grade. There was a good correlation between local tumor extent (T category), grading, and DNA parameters. Ta and T1 tumors had significantly lower levels of 5c exceeding rate and DNA grade of malignancy than muscle invasive carcinoma. Well-differentiated carcinoma (G1) also had lower levels than G2 and G3 tumors. As a result of earlier studies, a DNA-based risk-adapted concept for treatment has been developed for superficial tumors. First preliminary results of a clinical study are given in the present paper.

The Müller (glial) cell in normal and diseased retina: a case for single-cell electrophysiology

In the retina of most vertebrates there exists only one type of macroglia, the Müller cell. Müller cells express voltage-gated ion channels, neurotransmitter receptors and various uptake carrier systems. These properties enable the Müller cells to control the activity of retinal neurons by regulating the extracellular concentration of neuroactive substances such as K+, GABA and glutamate. We show here how electrophysiological recordings from enzymatically dissociated mammalian Müller cells can be used to study these mechanisms. Müller cells from various species have Na(+)-dependent GABA uptake carriers, but only cells from primates have additional GABA receptors that activate Cl- channels. Application of glutamate analogues causes enhanced membrane currents recorded from Müller cells in situ but not from isolated cells. We show that mammalian Müller cells have no ionotropic glutamate receptors but respond to increased K+ release from glutamate-stimulated retinal neurons. This response is involved in extracellular K+ clearance and is mediated by voltage-gated (inwardly rectifying) K+ channels which are abundantly expressed by healthy Müller cells. In various cases of human retinal pathology, currents through these channels are strongly reduced or even extinguished. Another type of voltage-gated ion channels, observed in Müller cells from many mammalian species, are Na+ channels. In Müller cells from diseased human retinae, voltage-dependent Na+ currents were significantly increased in comparison to cells from control donors. Thus, the expression of glial ion channels seems to be controlled by neuronal signals. This interaction may be involved in the pathogenesis of retinal gliosis which inevitably accompanies any degeneration of retinal neurons. In particular, Müller cell proliferation may be triggered by mechanisms requiring the activation of Ca(2+)-dependent K+ channels. Ca(2+)-dependent K+ currents are easily elicitable in Müller cells from degenerating retinae and can be blocked by 1 mM TEA (tetraethylammonium). In purified Müller cell cultures, the application of 1 mM TEA greatly reduces the proliferative activity of the cells. These data clearly show that Müller cells are altered in cases of neuronal degeneration and may be crucially involved in pathogenetic mechanisms of the retina.

[Nuclear magnetic resonance tomography examinations of the urogenital diaphragm in comparison with corresponding histomorphologic findings (the controversy concerning the musculus transversus perinei profundus)]

The transversus perinei profundus muscle is a well known structure in found anatomical textbook. Fibers of this muscle are believed to form the so-called external urethral sphincter (musculus sphincter urethrae). Recently histomorphologic investigations have shown that there is no muscular connection between the musculus sphincter urethrae (external sphincter) and the muscle system of the pelvic floor. Furthermore, the external sphincter was found to be divided into parts: the transversely striated part (musculus sphincter urethrae transversostriatus) and the smooth part (musculus sphincter urethrae glaber). Similar to histomorphologic investigations, contrast-enhanced MR imaging has shown the musculus sphincter urethrae to be surrounded by fatty and connective tissue only. Neither in MRI nor in anatomical slices can any connection between the urethral sphincter and the muscle system of the pelvic floor to be found. Thus, on the basis of the results presented in this work it is concluded that the musculus transversus perinei profundus does not exist in the form described in textbooks.

Pharmacological characteristics of potassium-induced, glycogenolysis in astrocytes

Elevated extracellular concentrations of the potassium ion ([K+]o) stimulate glycogenolysis in primary cultures of mouse astrocytes that have been grown in the presence of dibutyryl cyclic AMP but not in corresponding cultures which have not been treated in this manner. The response is potently inhibited by nifedipine, suggesting that it is evoked by entry of calcium ions through voltage dependent L-channels. The benzodiazepine midazolam, which is known to enhance calcium entry at concentrations of [K+]o causing submaximum calcium entry, increases the glycogenolytic effect by such levels of [K+]o.

Effects of enhanced extracellular ammonia concentration on cultured mammalian retinal glial (Müller) cells

Müller (glial) cells of the neonatal rabbit retina were cultured as confluent monolayers and exposed to enhanced concentrations of ammonia (0.25, 0.5, 1, 3, 7, and 10 mM) in medium for various periods (30 min to 10 d). This caused, in a time- and dose-dependent manner, similar changes in the Müller cells as had previously been described in cultured astrocytes. The most conspicuous events were 1) an increasing size of cell nuclei, 2) an accumulation of phagocytotic vacuoles, and 3) a rearrangement of intermediate filaments. 4) A considerable number of cells died when higher ammonia concentrations were applied for more than 1 h. Simultaneous application of dibutyryl-cyclic adenosine monophosphate (dBcAMP) prevented almost completely both the increase in cell nucleus size and the changes of intermediate filaments, but only partly the early cell death of a subpopulation of cells, and the accumulation of phagocytotic vacuoles. Further changes evoked by enhanced ammonia concentration were 5) an accumulation of lipofuscin-like material ("fatty degeneration") revealed by lipophilic stain, 6) reduced immunoreactivity for cathepsin D, and increased immunoreactivity for 7) glial fibrillary acidic protein, 8) glutamine synthetase, and 9) bcl-2 protooncogene protein. These findings are discussed in respect to the possible underlying pathophysiological mechanisms.

Further evidence that fluoxetine interacts with a 5-HT2C receptor in glial cells

It is generally believed that the antidepressant drug fluoxetine (Prozac) exerts all its effects by inhibition of serotonin uptake into neurons and an ensuing increase in the extracellular concentration of serotonin. However, these studies have confirmed and expanded our previous observation that fluoxetine on its own exerts agonist effects on astrocytes (a glial cell type), which resemble those exerted by serotonin. Fluoxetine appears to act on a different subtype of receptor (the 5-HT2C receptor [in original terminology the 5-HT1C receptor]) than the one on which micromolar concentrations of serotonin are known to act in astrocytes (the 5-HT2A receptor [in original terminology the 5-HT2 receptor]). However, this study has shown that application of serotonin to these cells stimulates glycogenolysis and causes an increase in free cytosolic concentration of calcium that is not inhibited by the 5-HT2A selective antagonist, ketanserin. Moreover, both effects are pronounced at the low nanomolar level of serotonin and, therefore, by definition, act on the 5-HT2C receptor. The concentration/response correlation is identical for the serotonin effects on free cytosolic calcium concentration and on glycogenolysis. Fluoxetine exerts similar effects, but low nanomolar concentrations have no effect, and the concentration required to obtain half-maximum response is 1-3 microM, a concentration dependence that is consistent with the plasma levels of fluoxetine during treatment with this drug.(ABSTRACT TRUNCATED AT 250 WORDS)

A new theory of micturition and urinary continence based on histomorphological studies. 4. The musculus dilator urethrae: force of micturition

In an anatomical study of serial sections of the bladder neck taken from 65 cadavers of all age groups the ventral longitudinal muscle system is shown as a single unit. It is characterized by two origins and two insertions. A detailed description is given. It should be emphasized that there is no connection between this muscle system and any muscle layer of the urinary bladder. The muscle bundles of the upper part of the ventral longitudinal urethral muscle system cross in stages the whole ventral circumference of the trigonal sphincter muscle with functional consequences. The lower part is closely combined with the lumen of the urethra. During contraction the muscle could be able to open the musculus sphincter trigonalis and the musculus sphincter urethrae; we called them musculus dilator urethra. Summarizing all presented histomorphological results of parts 1-4 of these papers [Dorschner et al.; Urol Int 52;1994] a new theory of micturition and its initiation is presented.

A new theory of micturition and urinary continence based on histomorphological studies. 5. The musculus ejaculatorius: a newly described structure responsible for seminal emission and ejaculation

Theories of seminal emission and ejaculation based on morphology especially of the dorsal longitudinal urethral muscle system are found very infrequently in the literature. Our own examinations carried out on serial sections of the whole distal urethral complex taken from 50 male and 15 female autopsy preparations prove that the dorsal longitudinal urethral muscle system represents an independent smooth muscle. In the female, the muscle system runs outside the sphincter system. In the male, it is the direct continuation of the musculature of the ejaculatory ducts and its expansion is generally restricted to the urethra below the colliculus seminalis. Within the urethra the urethral crest is protruded. Differences in the degree of the formation of the muscle in various age groups will be described. For this newly described muscle structure, we suggest the term musculus ejaculatorius as, due to purely anatomic reasons, an involvement in the process of ejaculation seems to be conclusive. A theory of seminal emission and ejaculation is given as a mass action of the musculature of the bladder neck.

A new theory of micturition and urinary continence based on histomorphological studies. 2. The musculus sphincter vesicae: continence or sexual function?

Results of a histomorphological study of serial sections carried out in frontal, transversal and sagittal directions in 65 bladder necks are presented. It is shown that the trigonal system of the urinary bladder consists of two anatomical structures: first, of a muscle originating from the muscle system of both ureters and converging to form within the bladder the interureteric ridge, the musculus interuretericus and of a second structure forming the actual trigonum vesicae. It is the musculus sphincter trigonalis or musculus sphincter vesicae. This muscle elliptically embraces the internal urethral orifice and is only formed by one muscle lamella. It does not as has often been described extend in any form to the urethra or to the surroundings. The so-called Bell muscle does not exist. During the reproductive years the lower part of the sphincter trigonalis is strongly pervaded with prostate tissue. This could enable the muscle to have a double function: a continence function in accordance with a consequent distinction between the urinary bladder and the urethra as urinary and sexual tract, and during ejaculation the muscle could prevent the retrograde ejaculation and on the other hand the contraction of the muscle could lead to the release of the prostate secretion.

A new theory of micturition and urinary continence based on histomorphological studies. 3. The two parts of the musculus sphincter urethrae: physiological importance for continence in rest and stress

The urethral component of continence is the object of a lively discussion. A large number of the examiners interpret the external striated urethral muscle as part of the muscular pelvic diaphragm, formed partially or completely by the so-called musculus transversus perinei profundus. About 30,000 histological sections have been examined by light microscopy in a systematical manner. In contrast to numerous suggestions in the literature the musculus sphincter urethrae has been found to be an independent morphological unit in our investigation. It is separated from the surroundings by a segment of connective tissue. Furthermore, with the help of transversal, sagittal and frontal serial sections it was possible to show that the musculus transversus perinei profundus does not exist. In the female as well as in the male in the direction of the urethra the outer sphincter always borders on a layer of smooth muscle cells. In order to distinguish both parts the terms musculus sphincter urethrae transversostriatus and musculus sphincter urethrae glaber are introduced. In the context of a new continence theory three structures capable of occluding the urinary bladder will be discussed. It should be emphasized that the musculus sphincter urethrae glaber makes long-term continence possible.

A new theory of micturition and urinary continence based on histomorphological studies. 1. The musculus detrusor vesicae: occlusive function or support of micturition?

Micturition and urinary continence theories have been under discussion since the last century. Up to now all these theories have been unsatisfactory. There is an obvious discrepance between the anatomical presentation and the clinical perceptions and physiological phenomena. This was the reason for a renewed and global examination of the whole distal urinary tract. The results are published in five successive papers. Our own examinations are based on 30,000 serial sections of the bladder neck taken from 65 male and female cadavers of all age groups. The muscle system of the urinary bladder consists of a network of smooth muscle cells forming three layers. Caudally the longitudinal muscle layers form two special recently described structures: the collare vesicae and nodus vesicae. None of the muscle systems of the urinary bladder leaves the spatial dimension of the organ. Simply two anatomical structures fix the urinary bladder in the pelvis. Dorsally it is the musculus vesicoprostaticus and the musculus vesicovaginalis, respectively; ventrally the existence of the musculi pubovesicales is introduced. There is no involvement of the lamellas of the bladder muscles in the formation of the urinary sphincter. Therefore the morphological substrate for a hitherto generally acknowledge contribution of the detrusor vesicae to the active continence function does not exist.

What do retinal müller (glial) cells do for their neuronal 'small siblings'?

Müller (radial glial) cells are the predominant glia of the vertebrate retina. They arise, together with rod photoreceptor cells, bipolar cells, and a subset of amacrine cells, from common precursor cells during a late proliferative phase. One Müller cell and a species-specific number of such neurons seem to form a columnar unit within the retinal tissue. In contrast, 'extracolumnar neurons' (ganglion cells, cone photoreceptor cells, horizontal cells, and another subset of amacrine cells) are born and start differentiation before most Müller cells are generated. It may be essential for such neurons to develop metabolic capacities sufficient to support their own survival, whereas late-born ('columnar') neurons seem to depend on a nursing function of their 'sisterly' Müller cell. Thus, out of the cell types within a retinal column it is exclusively the Müller cell that possesses the enzymes for glycogen metabolism. We present evidence that Müller cells express functional insulin receptors. Furthermore, isolated Müller cells rapidly hydrolyse glycogen when they are exposed to an elevated extracellular K+ ion concentration, a signal that is involved in the regulation of neuronal-glial metabolic cooperation in the brain. Müller cells are also thought to be essential for rapid and effective retinal K+ homeostasis. We present patch-clamp measurements on Müller cells of various vertebrate species that all demonstrate inwardly rectifying K+ channels; this type of channel is well-suited to mediate spatial buffering currents. A mathematical model is presented that allows estimation of Müller cell-mediated K+ currents. A simulation analysis shows that these currents greatly limit lateral spread of excitation beyond the borders of light-stimulated retinal columns, and thus help to maintain visual acuity.

Rabbit retinal Müller cells in cell culture show gap and tight junctions which they do not express in situ

Retinae of early postnatal rabbits were enzymatically dissociated and explanted in a culture system. The prospective myelinated region was discarded in order to avoid the presence of astrocytic or mesenchymal cells. After about 14 days in vitro (DIV), outgrowing glial (Müller) cells formed what light optically appeared to be confluent monolayers but by electron microscopy was shown to consist of flat epithelioid cells which overlapped considerably by extension of cytoplasmic tongues. Applying the freeze-fracture technique, apposed membranes of these cells were demonstrated to express infrequently but consistently both gap and tight junctions. This kind of junctions has never been observed on the membrane of rabbit Müller cells in situ. In comparison with Müller cell membranes in situ, the density of intramembrane particles was considerably reduced. Orthogonal arrays of particles which are characteristic elements of Müller cells in situ were not detected. Our results suggest that in homogeneous cell culture, Müller cells form some kind of epithelium-like specialized intercellular junctions. This situation resembles that of closely related glial cell types which form homogeneous layers in situ as e.g. retinal pigment epithelium cells expressing tight junctions, and marginal astrocytes being coupled by extensive gap junctions.

Size and density of glial and neuronal cells within the cerebral neocortex of various insectivorian species

Morphometric measurements were done on frontal sections through the somatosensory neocortex of various insectivorian species. All measured parameters varied with the size of animals; there was a better correlation with the ventriculartopial brain wall thickness than with the brain weight. The following rules were evaluated: with increasing brain wall thickness, 1) lamina I becomes thinner; 2) the nuclei of both neuronal and glial cells become larger; 3) the volume density of neuronal cells decreases greatly; 4) the volume density of glial cells increases slightly; and 5) as a result, the glia:neuron index increases markedly. There was no equal number of neurons under a unit surface area in the cortices of any species studied. Developmental processes that might account for the above-mentioned rules are discussed in this report.