A prospective randomized trial evaluating endoscopic Nd:YAG laser prostate ablation with or without potassium titanyl phosphate (KTP) laser bladder neck incision.

OBJECTIVE: To investigate whether performing a potassium titanyl phosphate (KTP) laser bladder neck incision (BNI) in conjunction with a Nd:YAG endoscopic ablation of the prostate (ELAP) compared with an ELAP alone, improves early post-operative voiding rates and clinical outcome. PATIENTS AND METHODS: A prospective randomized trial that was both double-blind and power-determined (80%) compared 88 patients with benign prostatic enlargement undergoing ELAP and those undergoing KTP BNI and ELAP. A dual-wavelength KTP/532TM (Laserscope) laser was used with Add/Stat side-firing fibres. A urethral catheter was inserted post-operatively and was removed after 18 h. Patients unable to void at this stage were then re-catheterized, discharged and readmitted 2 weeks later for catheter removal. Patients were followed up at 3 month intervals. RESULTS: Post-operatively, 80% of the patients undergoing KTP BNI and ELAP were able to void on catheter removal at 18 h, compared with only 57% of the patients undergoing ELAP alone (P < 0.05, chi-square). After 1 month, two patients from the former and four from the latter group failed to void and required further surgery. At 3 months, there was a significant improvement in the post-void residual volume, maximum flow rate, symptom and quality-of-life scores compared to the pre-operative values for both groups (P < 0.005). However, there was a greater improvement in the flow rate and symptom score in patients undergoing KTP BNI and ELAP (P < 0.05). CONCLUSION: This study shows the benefit of performing a KTP BNI with ELAP in terms of early voiding rates and initial clinical outcome, and this treatment is recommended.

Measurement of intracellular pH in isolated human detrusor smooth muscle cells.

Intracellular pH, pHi, was measured in isolated human detrusor smooth muscle cells by epifluorescence microscopy. The mean value was 7.07 +/- 0.19 when superfused with a CO2/HCO3- solution. Alteration of superfusate PCO2 also changed pHi whereas NaHCO3 changes were without effect, suggesting that the cell membrane is permeable to CO2 but impermeable to HCO3-. Nonbicarbonate H+ buffering power of the cell was calculated as 20.3 mequiv. x 1(-1) x pH unit-1. Addition of NH4Cl to the superfusate induced an alkalosis and, upon removal, a transient acidosis. The recovery from the acidosis allowed calculation of the acid extrusion rate from the cell. The rate was dependent on pHi and increased as the cell was more acid.

The actions of extracellular H+ on the electrophysiological properties of isolated human detrusor smooth muscle cells.

1. The influence of extracellular pH changes on intracellular pH and [Ca2+], as well as on L-type Ca2+ currents, has been investigated in isolated human detrusor smooth muscle cells. 2. Alteration of extracellular pH by changing superfusate PCO2 also changed intracellular pH. A change of superfusate pH made by altering the [NaHCO3] at constant PCO2 was not reflected in a change in intracellular pH. 3. Extracellular acidosis attenuated the magnitude and rate of change of intracellular [Ca2+] evoked by raising the extracellular [KCl]. 4. Extracellular acidosis attenuated the rate of rise and amplitude of the action potential, as well as the magnitude of the L-type Ca2+ current. In the pH range 6.78-7.62 no alteration to the voltage dependence of Ca2+ current activation or inactivation was recorded. 5. A close proportional relationship between tension generated by multicellular strips and the magnitude of peak inward Ca2+ current in isolated cells was noted over a wide range of the two variables using a number of interventions, including alteration to extracellular pH, [Ca2+] and [Mg2+]. 6. Extracellular acidosis attenuated the magnitude of caffeine-dependent intracellular Ca2+ transients and the resting [Ca2+]i between transients. Acidosis was without effect on the rise of [Ca2+]i induced by carbachol. 7. The results suggest that the negative inotropic effect of extracellular acidosis can be accounted for by attenuation of the L-type Ca2+ current. The results also imply that intracellular stores are influenced by transmembrane Ca2+ fluxes at rest and that such fluxes are also attenuated by extracellular H+.

Alterations to the electrophysiology of isolated human detrusor smooth muscle cells in bladder disease.

The aim of the study was to investigate the properties of the inward calcium current (iCa) obtained from isolated human detrusor smooth muscle cells in different pathological conditions using the whole-cell patch-clamp technique. Previous experiments on field stimulated detrusor muscle strips have shown specific differences associated with hypertrophy and detrusor instability. As iCa plays an important role in excitation-contraction coupling in this tissue, it was therefore of interest to determine if iCa was altered in the above disease states. It was found that myocytes from patients with prostatic symptoms had a significantly increased surface area and that the kinetics of iCa were also significantly altered in these cells. Although the surface area of cells from patients with idiopathic instability and detrusor hyperreflexia was also significantly increased, the kinetics of iCa were altered in different ways. These alterations to iCa will alter the action potential configuration and its propagation through the muscle mass.

Urethral catheterisation--is anybody listening?

All house officers perform male urethral catheterisation and although complications may occur awareness of the potential problems varies considerably. 43 house officers from 12 different medical schools were interviewed to determine the amount of training that they received regarding this procedure as students and during their first pre-registration post. The results suggest that there is no planned approach to teaching urethral catheterisation which would be in the interests of both junior doctors and patients alike.