Epithelial cell volume regulation: bicarbonate dependence.

When Necturus gallbladder epithelial cells are osmotically shrunken, they rapidly return to their original volume despite the continued presence of a hypertonic bathing solution. This volume-regulatory process requires bicarbonate ions in the bathing solutions and is associated with the uptake of chloride ions. Volume-regulatory increase by epithelial cells in probable due to the parallel operation of sodium-hydrogen and chloride-bicarbonate exchangers in the apical cell membrane.

FSH suppression and tumour control in patients with prostate cancer during androgen deprivation with a GnRH agonist or antagonist.

BACKGROUND: Gonadotropin releasing hormone (GnRH) antagonists suppress follicle-stimulating hormone (FSH) to lower levels than GnRH agonists. This may partially explain the differences between these agents on prostate cancer outcomes. In this post-hoc analysis, FSH and prostate specific antigen (PSA) responses and the impact of cross-over from leuprolide to degarelix were evaluated from a 1-year comparative study (CS21) and its extension study (CS21A). MATERIALS AND METHODS: Overall, 610 patients were enrolled in CS21, wherein PSA and FSH levels were evaluated monthly. CS21A evaluated 386 patients, including those previously treated with degarelix (n = 251) who continued to receive degarelix, and those previously treated with leuprolide (n = 135) who crossed-over to receive degarelix. PSA and FSH levels were evaluated in CS21A for 3 months after cross-over. The associations between measurements were assessed using Spearman's correlation coefficient. The impact of class variables on FSH suppression were evaluated using Analysis of Variance. RESULTS: Rapid PSA and FSH suppression was observed and maintained in the degarelix arm (CS21 and CS21A), while patients on leuprolide experienced rising PSA during CS21. Patients crossed-over from leuprolide to degarelix achieved a suppression of FSH and a significant PSA decrease. PSA and FSH levels were significantly (p < .05) correlated at months 1, 3, 6, 12 and 13 in the degarelix arm. CONCLUSIONS: Significant FSH suppression with GnRH antagonists may explain its advantage over GnRH agonists in terms of better prostate cancer control. The effect of profound FSH suppression is analogous to the need for profound testosterone suppression for tumor control.

Permeability properties of the subepithelial tissues of Necturus gallbladder.

The permeability properties of the subepithelial connective tissue of Necturus gallbladder were evaluated by measurement of electrical resistance, dilution potentials and hydraulic water permeability. The gallbladder epithelial cells were removed by scraping and the underlying connective tissue placed in an Ussing chamber. The electrical resistance was 2.2 +/- 0.8 omega X cm2; the tissue was slightly cation selective relative to free solution. The subepithelial tissues restricted the rate of diffusion of small solutes to 50% of the free solution value. The hydraulic water permeability averaged 2.1 X 10(-2) cm/s per atm. We conclude that limitations of the area of subepithelium available for fluid movement are the most important factors in determining the restrictions to solute and water flow offered by the subepithelial tissues.

Prognostic factors in clinical stage I nonseminomatous germ cell tumors of the testis: multivariate analysis of a prospective multicenter study. Swedish-Norwegian Testicular Cancer Group.

Between 1981 and 1986, 279 consecutive patients with clinical stage I (CS1) nonseminomatous germ cell tumors (NSGCT) of the testis underwent pathological staging (PS) with retroperitoneal lymphadenectomy (RPLND). Patients with retroperitoneal metastases (PS2) received adjuvant chemotherapy. The median follow-up time after RPLND was 50 months (range, 30 to 90). Clinical and histopathologic features were registered prospectively and analyzed for association with risk of having PS2, relapse despite pathological stage 1 (PS1) or the combined risk of either event, metastatic disease (MET). Seventy-five (26.9%) of the patients had PS2 disease, and 30 (14.7%) of the 204 PS1 patients relapsed, indicating that at least 105 (37.6%) of this CS1 population had subclinical MET at the time of orchiectomy. Four (1.4%) of the 279 CS1 patients died of testicular cancer. Multivariate analyses showed several variables to be significantly associated with outcome for the CS1 patients; vascular invasion in primary tumor and normal preorchiectomy serum alpha-fetoprotein (Pre-AFP) level indicated PS2 disease. If Pre-AFP was excluded from the model, the absence of teratoma or yolk sac elements in the primary tumor became significant predictors of PS2. Vascular invasion, absence of teratoma, and a short interval between orchiectomy and RPLND indicated increased risk of relapse in PS1 patients. Vascular invasion, normal Pre-AFP, absence of teratoma elements, and a short orchiectomy to RPLND interval were predictive of MET. Our results indicate that prognostic factors useful for stratification of CS1 patients with NSGCT to different treatment options may be established.

Gallbladder epithelial cell hydraulic water permeability and volume regulation.

The hydraulic water permeability (Lp) of the cell membranes of Necturus gallbladder epithelial cells was estimated from the rate of change of cell volume after a change in the osmolality of the bathing solution. Cell volume was calculated from computer reconstruction of light microscopic images of epithelial cells obtained by the "optical slice" technique. The tissue was mounted in a miniature Ussing chamber designed to achieve optimal optical properties, rapid bath exchange, and negligible unstirred layer thickness. The control solution contained only 80% of the normal NaCl concentration, the remainder of the osmolality was made up by mannitol, a condition that did not significantly decrease the fluid absorption rate in gallbladder sac preparations. The osmotic gradient ranged from 11.5 to 41 mosmol and was achieved by the addition or removal of mannitol from the perfusion solutions. The Lp of the apical membrane of the cell was 1.0 X 10(-3) cm/s . osmol (Posm = 0.055 cm/s) and that of the basolateral membrane was 2.2 X 10(-3) cm/s . osmol (Posm = 0.12 cm/s). These values were sufficiently high so that normal fluid absorption by Necturus gallbladder could be accomplished by a 2.4-mosmol solute gradient across the apical membrane and a 1.1-mosmol gradient across the basolateral membrane. After the initial cell shrinkage or swelling resulting from the anisotonic mucosal or serosal medium, cell volume returned rapidly toward the control value despite the fact that one bathing solution remained anisotonic. This volume regulatory response was not influenced by serosal ouabain or reduction of bath NaCl concentration to 10 mM. Complete removal of mucosal perfusate NaCl abolished volume regulation after cell shrinkage. Estimates were also made of the reflection coefficient for NaCl and urea at the apical cell membrane and of the velocity of water flow across the cytoplasm.

Tubuloglomerular feedback and chloride activity in the juxtaglomerular interstitium in Amphiuma.

Fresh-water animals excrete large volumes of dilute urine. The pronounced dilution of the tubular fluid starts in the early distal tubule. In this paper the reabsorptive capacity of the diluting segment is discussed, with special attention to the maximal salt concentration of the reabsorbed fluid. Earlier studies have shown a reabsorption-dependent chloride concentration on the basolateral side of the epithelium (juxtaglomerular interstitium, JGI) at the site of the juxtaglomerular apparatus. In the present study measurements were made of chloride activities in the immediate vicinity of the basolateral side of the tubular epithelial cells at high and low tubular perfusion rates. Extremely high chloride activities (2451 +/- 625 mM (SE), n = 7) were found in the JGI at maximal reabsorption, while more plasma-like values were noted at zero tubular flow. The flow-dependent salt reabsorption may be a powerful signal for tubuloglomerular feedback from the tubular lumen to the effector cells.

Structural and functional studies of gap junctions in human myometrium.

Gap junctions are of importance in the coordinated contraction of uterine smooth muscle during labor. There are indications that in the human myometrium, gap junctions are much more numerous in the period immediately surrounding parturition. The presence and the functional state of gap junctions in human myometrium was studied by electron microscopical morphometry and by studying the distribution of an injected fluorescent dye. Electron microscopy showed that the number and size of gap junctions was significantly higher during the active phase of labor than during the pre-labor phase. Pressure injection of Lucifer Yellow into myometrial cells in vitro showed only weak coupling in the pre-labor stage. These data support the notion that coupling between myometrial cells develops in immediate association with parturition.

Survival and clinical metastases among prostate cancer patients treated with androgen deprivation therapy in Sweden.

OBJECTIVES: To examine the incidence of metastases and clinical course of prostate cancer patients who are without confirmed metastasis when initiating androgen deprivation therapy (ADT). METHODS: Retrospective cohort study conducted using electronic medical records from Swedish outpatient urology clinics linked to national mandatory registries to capture medical and demographic data. Prostate cancer patients initiating ADT between 2000 and 2010 were followed from initiation of ADT to metastasis, death, and/or end of follow-up. RESULTS: The 5-year cumulative incidence (CI) of metastasis was 18%. Survival was 60% after 5 years; results were similar for bone metastasis-free survival. The 5-year CI of castration-resistant prostate cancer (CRPC) was 50% and the median survival from CRPC development was 2.7 years. Serum prostate-specific antigen (PSA) levels and PSA doubling time were strong predictors of bone metastasis, any metastasis, and death. CONCLUSION: This study provides understanding of the clinical course of prostate cancer patients without confirmed metastasis treated with ADT in Sweden. Greater PSA values and shorter PSA doubling time (particularly ≤ 6 months) were associated with increased risk of bone metastasis, any metastasis, and death.

A randomised comparison of oral desmopressin lyophilisate (MELT) and tablet formulations in children and adolescents with primary nocturnal enuresis.

AIMS: Desmopressin is a useful treatment for primary nocturnal enuresis (PNE), a common childhood condition that can persist into adolescence. This open-label, randomised, cross-over study evaluated the preference of children and adolescents with PNE for sublingual desmopressin oral lyophilisate (MELT) vs. tablet treatment, and the efficacy, safety, compliance and ease of use associated with each formulation. In total, 221 patients aged 5-15 years who were already receiving desmopressin tablets were randomised 1 : 1 to receive desmopressin treatment in the order MELT/tablet (n = 110) or tablet/MELT (n = 111) for 3 weeks each. Each formulation was administered in bioequivalent doses (0.2/0.4 mg tablets identical with 120/240 microg MELT). Following treatment, patients were questioned regarding treatment preference. Diary card data and 100 mm Visual Analogue Scale scores were also recorded. RESULTS: Overall, patients preferred the MELT formulation to the tablet (56% vs. 44%; p = 0.112). This preference was age dependent (p = 0.006); patients aged < 12 years had a statistically significant preference for desmopressin MELT (p = 0.0089). Efficacy was similar for both formulations (MELT: 1.88 +/- 1.94 bedwetting episodes/week; tablet: 1.90 +/- 1.85 episodes/week). Ease of use of both formulations was high. Compliance (> or = 80%) was 94.5% for MELT patients vs. 88.9% for the tablet (p = 0.059). No serious/severe adverse events were reported. CONCLUSIONS: There was an overall preference for the MELT, and a statistically significant preference for desmopressin MELT in children aged 5-11 years. Desmopressin MELT had similar levels of efficacy and safety at lower dosing levels than the tablet, and therefore facilitates early initiation of PNE treatment in children aged 5-6 years.

Dynamics of glomerular ultrafiltration in Amphiuma means.

To study renal function in Amphiuma means, the hydrostatic pressures in vascular and tubular structures and the glomerular filtration rate were determined at different arterial blood pressures. In the arterial blood pressure range studied no evidence of autoregulation of the glomerular capillary pressure of the hydrostatic pressure gradient over the capillary membrane was found. The glomerular filtration ceases at an arterial blood pressure below 12 cm H2O. No significant difference between tubular free flow pressure and peritubular capillary pressure was noted. Furthermore, it was found that the glomerular capillary pressure could be estimated by measuring the intratubular stop-flow pressure and arterial colloid osmotic pressure at an arterial pressure above 15 cm H2O. It was also found possible to measure the glomerular capillary pressure at the very end of the afferent arteriole. The protein concentrations in afferent and efferent arteriolar blood were determined and the colloid osmotic pressures were calculated according to a new formula derived for Amphiuma plasma. The dynamics of glomerular ultrafiltration was evaluated. A filtration equilibrium across the glomerular membrane was reached, since the efferent colloid osmotic pressure was not significantly different from the hydrostatic pressure gradient across the glomerular capillary membrane.

GFR regulation and flow-dependent electrophysiology of early distal tubule in Amphiuma.

Tubuloglomerular feedback (TGF) in mammals and amphibians senses flow-dependent concentration changes in tubular fluid of the distal tubule and signals to arterioles to initiate changes in glomerular filtration rate. The distal tubules and afferent arterioles are situated on the surface of the kidney of Amphiuma means. Micropuncture techniques were used to measure luminal and intracellular chloride concentrations and the associated electrical potential differences, while tubular perfusion rate was varied. Transepithelial potential difference (PDte) and basolateral potential difference (PDbl) became more positive at increased tubular flow rates. Intratubular and intracellular chloride concentrations also increased significantly with perfusion rate. Single-nephron glomerular filtration rate decreased when perfusion rate was increased but this response was eliminated by the inclusion of furosemide in the perfusion solution; the drug also inhibited the flow dependence of PDte. The results suggest that local changes in PD and Cl- activity result from flow-dependent changes in the rate of hypertonic NaCl transport propagated along the length of the perfused segment; they establish a correlation between the rate of transport and the magnitude of the TGF inhibition; and, because transport and TGF can be jointly inhibited, they suggest a causal link between the two.

Carbonic anhydrase inhibition and cell volume regulation in Necturus gallbladder.

Gallbladder epithelial cells transport salt and water isotonically as the renal proximal tubule. The cells also have the property of regulating their cell volume in response to osmotic stress (Fisher et al. 1981, Persson & Spring 1982, Fisher & Spring 1984, Foskett & Spring 1985). The volume-regulating phenomenon is the result of a balance between cell uptake of salt and water at the luminal membrane and exit at the basolateral membrane. Different properties regarding volume regulatory increase and decrease have been found (Eriksson & Spring 1982 and Larson & Spring 1983). The present study links fluid transport and volume regulatory increase of the cell. First we concluded from histological techniques that carbonic anhydrase is present in the cell membrane or in the vicinity of the epithelial cells. Then we measured a decreased net fluid transport in the presence of increasing concentrations of the carbonic anhydrase inhibitor acetazolamide. We showed that the volume regulatory increase is substantially slowed down and that the steady-state volume of the cells changed when carbonic anhydrase was inhibited. Our conclusion is that the rate of CO2 hydration was a limiting step, at carbonic anhydrase inhibition, in both the net transfer of salt and water and also in the ability of the cells to efficiently regulate their volume.

Allopurinol treatment results in elevated prostate-specific antigen levels in prostatic fluid and serum of patients with non-bacterial prostatitis.

Non-bacterial prostatitis is a common problem in young men. It is a disease which is often recurrent and each episode lasts for several months. Different causative mechanisms of the disease have been discussed including identified and non-identified microorganisms, stone formation and psychological factors. It was shown in an earlier study that urinary reflux (as shown by a high creatinine concentration in prostatic fluid) took place to a varying extent in the prostatic ducts and this reflux was related to prostatic pain and urate concentration in expressed prostatic secretion (EPS). Allopurinol treatment lowered the urate concentration in EPS and relieved the subjective discomfort. This study reports serum (S) levels of prostate-specific antigen (PSA) in patients with non-bacterial prostatitis and the way in which S-PSA was affected by allopurinol treatment. It is also shown that the S-PSA level is age dependent. A correlation existed between the S-PSA concentration and EPS content of white blood cells. Patients with high EPS urate concentrations corresponded to low S-PSA levels and allopurinol treatment resulted in elevated S-PSA levels. PSA in EPS was also increased by allopurinol treatment. Hence, an increased release of PSA from the prostate gland was noted upon allopurinol treatment. The mechanism of the allopurinol-induced release is obscure. It might be explained by an induction of PSA synthesis via an allopurinol effect on the genome but an increased leakage of the prostatic cells elicited by allopurinol could no be ruled out.

Evidence for a mechanistic association between nonbacterial prostatitis and levels of urate and creatinine in expressed prostatic secretion.

PURPOSE: Chronic prostatitis is a common disease of the late teenage years, which affects patients for many years. In the majority of cases etiology is unknown but in some cases prostatitis is clearly caused by microorganisms that result from overuse of antibiotic drugs. We attempt to gain further knowledge about the etiology of the disease. MATERIALS AND METHODS: We studied 56 patients with nonbacterial prostatitis in regard to whether urine reflux into the prostatic ducts was responsible for increased concentrations of creatinine, urate and white blood cells in expressed prostatic secretion. The patients were interviewed using a standard questionnaire. RESULTS: A relationship was demonstrated between pain estimated in accordance with a scoring scale, and expressed prostatic secretion contents of white blood cells, urate and creatinine. CONCLUSIONS: These results provide further support of the role of reflux into the prostatic ducts as an underlying mechanism initiating a chemical inflammatory reaction. Urate appears to be the chemical agent eliciting this inflammatory response.

The existence of a tubulo-glomerular feedback mechanism in the Amphiuma nephron.

A single nephron tubulo-glomerular feedback control of the glomerular filtration rate, which is known in mammalian animals, could be one way by which amphibians regulate the glomerular filtration rate (GFR). To investigate whether the Amphiuma means shows any sign of a tubulo-glomerular feedback control, micropuncture experiments were carried out. Six different series of experiments were performed. In the first series, tubular stop-flow pressure (SFP) was measured during distal tubular perfusion with amphibian Ringer solution at a rate of 10, 25 and 50 nl/min. A significant decrease of SFP was found at the three perfusion rates compared to the controls. In the second group, single nephron glomerular filtration rate (SNGFR) was measured, while the distal tubule was perfused at 10, 25 and 50 nl/min. At a perfusion rate of 10 nl/min the SNGFR did not decrease, whereas at 25 and 50 nl/min it decreased significantly. In the third group the perfusion pipette was located in the proximal tubule and the nephron was perfused at 10, 25 and 50 nl/min, while at the same time the proximal tubular stop-flow pressure was measured. No reduction of SFP was found at a perfusion rate of 10 nl/min, while significant reductions were noted at rates of 25 and 50 nl/min. In the fourth group the SNGFR was measured in the distal tubule beyond the macula densa and in Bowman's space of the same nephron. No significant difference was found. In the fifth group, the glomerular capillary pressure (GCP) was measured before and after blockade of the tubular fluid flow. No significant difference was found between these two measurements. The sixth series deals with the changes occurring at the single nephron level by the tubulo-glomerular feedback control. The single nephron filtration fraction (FF) was determined from efferent arteriolar protein concentration with and without a feedback-induced reduction of the SNGFR. The FF values were not significantly different from one another. From these results and data from the other series, the afferent (Raff) and efferent (Reff) arteriolar resistances were calculated. Reff did not change, while Raff increased significantly when a feedback stimulus was applied. These experiments indicate the existence of a tubulo-glomerular feedback control which depresses the SNGFR and SFP by contracting the afferent arteriole.

Acidification in the distal tubule of the Amphiuma kidney.

The acidification of the urine within the distal tubule of Amphiuma means was studied with micropuncture techniques. Antimony microelectrodes calibrated in vivo were used for measuring the intratubular pH and samples were taken for the determination of Na+- and Cl- -concentrations and for determining buffer lines within the HCO-3-CO2 buffer system. The TF/P Na+ was used as a relative length determinator and a significant acidification along the length of the tubule was found. The pH in the tubule was more acid than samples equilibrated at blood PCO2. This disequilibrium can be described in terms of an imbalance within the Henderson-Hasselbach formula or/and as a PCO2-gradient across the tubular wall. The calculated PCO2-gradient was found to be correlated to the arterial PCO2 and the acidification to the arterial pH. The greatest pH-gradient is generated in the collecting duct and in the bladder.

Juxtaglomerular interstitial hypertonicity in Amphiuma: tubular origin-TGF signal.

One of the mechanisms mediating renal vascular autoregulation in mammals senses tubular flow rate-dependent changes in luminal NaCl concentrations and signals renal arterioles to change diameter. A similar mechanism operates in the salamander, Amphiuma means. To trace the signal, we measured chloride activity in juxtaglomerular interstitial spaces in Amphiuma during perfusion of the early distal tubule belonging to the same nephron. Interstitial Cl- activity exceeded systemic levels and increased when perfusion rate in the adjacent early distal tubule was increased, reaching values more than five times isotonic. Bumetanide, which inhibits NaCl transport by the early distal tubule, eliminated the hypertonicity. Regions of the interstitial space not a part of the juxtaglomerular apparatus (JGA) were not hypertonic. The Cl- concentration was 80% greater than isotonic in the JGA of nephrons studied under free-flow conditions. Single-nephron blood flow, measured by counting the flux of erythrocytes labeled with a fluorescent molecule, showed typical feedback inhibition with maximum sensitivity to the same rates of tubular perfusion that caused the maximum change in JGA interstitial hypertonicity. Juxtaglomerular interstitial hypertonicity could be an important part of the signal for renal autoregulation.

Uridine, xanthine and urate concentrations in prostatic fluid and seminal plasma of patients with prostatitis.

The etiology of prostatitis is not fully understood and several causative factors have been considered in the past. In this study we analyzed the expressed prostatic secretion (EPS) and seminal plasma with regard to uridine, xanthine, urate, creatinine and zinc from patients with prostatitis (the diagnosis was based on symptoms for at least 1 year), together with creatinine, urate and zinc in the serum. In 8 of the patients, a direct comparison of these constituents was performed between EPS and seminal plasma. EPS contained low concentrations of uridine and xanthine and high concentrations of creatinine and zinc as opposed to seminal plasma that displayed a reverse pattern. The mean urate concentration in seminal plasma, exceeding that of EPS by 78%, was rather close to the mean value found in serum but no significant correlation was seen between urate in serum and urate in seminal plasma or EPS. Urate in EPS correlated significantly to xanthine in EPS and such a relationship was also observed between urate and creatinine in EPS. In seminal plasma, urate and xanthine were likewise correlated with each other. On division of the patients into a high-score symptom group and a low-score group, no intergroup differences were found in EPS and seminal plasma constituents. Hence, we found high concentrations especially of uridine and xanthine in seminal plasma, compared with other body fluids, and evidence of a backflow of urine mixing with the prostatic fluid of these patients was seen. We suggest that crystal formation of these metabolites may occur under certain conditions and could constitute a first step in the development of prostatitis-vesiculitis-epididymitis in some cases.

Optimizing the therapeutic approach of transurethral alprostadil.

OBJECTIVE: To investigate the efficacy and safety of two different starting doses of transurethral alprostadil (250 microg and 500 microg, MUSE, Vivus Inc., Menlo Park, CA, USA, and Astra Läkemedel AB, Södertälje, Sweden) and the need for dose titration in a general population with erectile dysfunction. PATIENTS AND METHODS: In a 12-week randomized and open multicentre study with parallel groups, 166 patients were randomised to a starting dose of either 250 or 500 microg of MUSE and evaluated for safety. Of these patients, 142 were included in the analysis of efficacy. MUSE marked in four doses (125, 250, 500 and 1000 microg) was supplied and during the trial the dose could be increased or decreased step-wise until a satisfactory response was attained. The efficacy was assessed using the Erection Assessment Scale (EAS), as coitus (by diary) and the International Index of Erectile Function. RESULTS: The lowest dose of MUSE with which the patients achieved at least one EAS score of 4 or 5 was 125 microg for 1% of participants, 250 ++microg for 27%, 500 microg for 32%, 1000 microg for 6%, and finally 1000 microg plus a pubic band for 8%. Thirty-five of the 142 patients (25%) did not report an EAS of 4 or 5. Most patients (> 60%) achieved an EAS of 4 or 5 on the lower doses (125, 250 and 500 microg). Almost all patients who had an EAS score of 4 or 5 also had intercourse. In all, 68% reported sexual intercourse at least once in course of the study. More patients reported penile pain while treated with 500 microg than with 250 microg (P < 0.05) during the first 4 weeks. However, the penile pain was severe in very few men and it was a minor problem. Hypotensive symptoms were reported six times, independently of dose level. The administration of MUSE was generally rated as comfortable. No patients reported urethral stricture, penile fibrosis, or priapism either in the clinic or at home. CONCLUSION: Recommending 500 microg as a starting dose increased the percentage of patients reporting at least one EAS of 4-5, with or without sexual intercourse, from 28% to 60%. No serious dose-related systemic effects were seen. When starting on 500 microg, patients were more likely to find directly the dose that gave sufficient response and treatment satisfaction. We suggest that the appropriate starting dose of MUSE should be 500 microg.