Reliability of the International Prostate Symptom Score in the assessment of patients with lower urinary tract symptoms and/or benign prostatic hyperplasia.

PURPOSE: The reliability of the International Prostate Symptom Score (I-PSS) was tested in patients with lower urinary tract symptoms and/or benign prostatic hyperplasia. MATERIALS AND METHODS: A total of 71 consecutive men with benign prostatic hyperplasia and/or lower urinary tract symptoms was asked to complete the I-PSS at baseline and 8 weeks later. At the second visit the physician also completed the I-PSS according to the complaints of the patient. Variability between both scores was evaluated by calculation of duplo errors and results were compared to the clinical data. RESULTS: A considerable variability existed between the I-PSS results obtained at baseline and 8 weeks. The duplo error was 4.3. In a regression analysis of I-PSS, including all clinical parameters, only free flow had some predictive value for I-PSS outcomes. CONCLUSIONS: It is important to consider the variability of the I-PSS score when making decisions concerning treatment.

The outcome of renal ultrasound in the assessment of 556 consecutive patients with benign prostatic hyperplasia.

PURPOSE: We determined the additional value of renal ultrasonography in the assessment of patients with benign prostatic hyperplasia. MATERIALS AND METHODS: Renal ultrasound was performed in 556 consecutive patients with benign prostatic hyperplasia and the results were correlated with other clinical parameters. RESULTS: Of the patients 14 (2.5%) had dilatation of the renal pelvis, 65 (11.7%) had renal cysts and 1 (0.18%) had renal cell carcinoma. The serum creatinine level appeared to be correlated with dilatation of the renal pelvis. To predict dilatation additional information can be obtained by including the results of the post-void residual measurements. CONCLUSIONS: Renal ultrasound is indicated only in patients with a specific serum creatinine level and/or post-void residual volume.

The predictive value of microscopic haematuria in patients with lower urinary tract symptoms and benign prostatic hyperplasia.

OBJECTIVE: To determine the additional value of the presence of microscopic haematuria in patients with benign prostatic hyperplasia (BPH). METHODS: In 750 consecutive patients with BPH urinalysis was performed and the grade of microhaematuria was correlated with other clinical findings. RESULTS: Microscopic haematuria was found in one third of the patients. Only 3 had a bladder tumour and 49 patients had urinary calculi for which only one patient required treatment. There was no correlations between any clinical parameter and the finding of microscopic haematuria. CONCLUSION: Microscopic haematuria is a frequent finding in assessment of BPH patients and additional tests should only be performed if indicated.

A dc Method for the Absolute Determination of Conductivities of the Primary Standard KCl Solutions from 0 °C to 50 °C.

A new method for the absolute determination of electrolytic conductivity based on direct current and Potentiometric measurements is described. The unique design of the cell uses a removable center section whose length and cross-sectional area are accurately known. Two pairs of matched Ag, AgCl electrodes are used in a four terminal mode of resistance measurement. Measurements of the electrolytic conductivity of primary standard potassium chloride solution using [his novel dc conductance cell are compared with the currently adopted IUPAC and OIML recommendations. In addition, measurements have heen made of the electrolytic conductivity of a solution of potassium chloride having a molality of 1 mol/kg (mole KCl per kilogram H2O). The values so obtained over the temperature range of 0 °C to 50 °C are recommended as the new primary standards for electrolytic conductivity.

Frozen human serum reference material for standardization of sodium and potassium measurements in serum or plasma by ion-selective electrode analyzers.

Three interlaboratory round-robin studies (RR1, RR2, and RR3) were conducted to identify a serum-based reference material that would aid in the standardization of direct ion-selective electrode (ISE) measurements of sodium and potassium. Ultrafiltered frozen serum reference materials requiring no reconstitution reduced between-laboratory variability (the largest source of imprecision) more than did other reference materials. ISE values for RR3 were normalized by the use of two points at the extremes of the clinical range for sodium (i.e., 120 and 160 mmol/L), with values assigned by the flame atomic emission spectrometry (FAES) Reference Method. This FAES normalization of ISE raw values remarkably improved all sources of variability and unified the results from seven different direct ISE analyzers to the FAES Reference Method value. Subsequently, a three-tiered, fresh-frozen human serum reference material was produced to the specifications developed in RR1-RR3, was assigned certified values for sodium and potassium by Definitive Methods at the National Institute of Standards and Technology (NIST), and was made available in 1990 to the clinical laboratory community as a Standard Reference Material (SRM); it is now identified as SRM 956. Albeit retrospectively, we show how applying an FAES normalization step identical to that used in RR4/5 to the ISE data for SRM 956 after the NIST Definitive Method values were known, consistently moved the ISE results for RR3 closer to the true value for Na+ and K+.

Proposed New Electrolytic Conductivity Primary Standards for KCl Solutions.

An absolute determination of aqueous electrolytic conductivity has been made for 0.01 molal (m) and 0.1 m potassium cliloride solutions, over the temperature range of 0 to 50 °C in 5 degree intervals. A cell with a removable center section of accurately known length and area was used for the measurements. Values were adjusted to be in conformity with the ITS-90 temperature scale. The overall uncertainty over the entire temperature range is estimated to be 0.03%. Values at 25 °C for 0.01 and 0.1 m are 0.00140823 and 0.0128246 S/cm, respectively. It is proposed that these values be adopted as primary standards for aqueous electrolytic conductivity, replacing the demal scale.

Investigation of the Interaction of Sodium Chloride and Two Amino Sulfonic Acids, HEPES and MOPSO, by EMF Measurements.

Ionic interactions in the two systems NaCl-HEPES (N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid) and NaCl-MOPSO (3-(N-Morpholino)-2-hydroxypropanesulfonic acid) have been studied in terms of their mutual influence on the respective activity coefficients of each component. Activity coefficients for each component of the two systems and for corresponding buffers are calculated from emf measurements of solutions containing NaCl, the aminosulfonic acid, and its conjugate base in a NalSE/solution/AgCl-Ag cell at 5, 15, 25, and 37 °C.

Further developments in the high-precision coulometric titration of uranium.

An experimental study of the current efficiency in the coulometric generation of Ti(III), as a function of electrolyte composition, current density and electrode material, has been performed. The cathodes investigated include platinum, mercury and graphite. The first two are suitable for high-precision determination of uranium. The graphite surface is readily poisoned, rendering it useless for high-accuracy work. The use of mercury requires thorough removal of chloride from the system. The precision and error obtained are comparable for both the mercury and platinum cathodes, and are of the order of 50 ppm.

A Report on the National Bureau of Standards pH Standards.

In 1980, the research program in pH was re-established at the National Bureau of Standards (NBS). This report describes the state of this research, as well as the state of the NBS pH standards. The thermodynamic definition and the determination of pH are elaborated. The problems of liquid junction potentials encountered in the practical determination of pH are discussed. The goal of the research program in pH is to develop and maintain a unified pH scale based on clearly stated thermodynamic criteria, with a wide range of applicability to practical pH measurements.

Chorioallantoic membrane grafting of the embryonic murine kidney. An improved in vitro technique for studying kidney morphogenesis.

Previous experimental investigations of embryonic kidney development with in vitro organ culture techniques have been limited by the short duration of explant viability. Utilization of chick chorioallantoic membranes for transplanting undifferentiated murine kidney rudiments has allowed vascularization of the grafts with advanced maturation and the appearance of early nephron units.

Direct Determination of Air Density in a Balance Through Artifacts Characterized in an Evacuated Weighing Chamber.

This paper describes a simple device which permits mass comparisons in air without appeal to the correction for air buoyancy. The device consists of a canister which is evacuated and weighed on a laboratory balance with a mass inside. A second weighing of another mass in the evacuated canister provides the desired mass comparison. The method was used to determine the mass difference between two stainless steel weights of widely differing densities. With knowledge of this mass difference and of the volume difference one may, by a simple air weighing of the two objects, determine directly the density of the air in the balance case. Densities of air determined by this method were compared with those calculated from the barometric pressure, the temperature, and the relative humidity of the laboratory air. The experimental and calculated values agree throughout to within 1.0 µg cm-3 (where the normal air density is about 1.2 mg cm-3). The calculated and experimental values of day-to-day fluctuations in air density agree to within 0.5 µg cm-3.

Additional results on the value of the faraday.

Repetition of the authors' earlier high-precision coulometric titrations of 4-aminopyridine by the hydrazine-platinum anode and back-titration methods, at the National Bureau of Standards, has yielded a new value for the Faraday, almost identical with the earlier value but with lower uncertainty. The earlier value has been recalculated, using a new value for the density of 4-aminopyridine. The weighted average of the new and old values is 96486.57 1972 NBS coulombs per equivalent, the standard deviation of the mean being 0.48 coulombs per equivalent (4.9 ppm).

A high-precision titration of 4-aminopyridine A value for the faraday.

A specimen of 4-aminopyridine purified by repeated sublimation in an atmosphere of nitrogen has been titrated coulometrically in two ways: (1) directly, using the hydrazine-platinum anode, and (2) with perchloric acid, the titration being completed coulometrically and the perchloric acid being standardized coulometrically. The values for the faraday calculated from these titrations are 96,486.40 (1.53) and 96,486.78 (0.57), 1972 NBS coulombs per mole, respectively, the average being 96,486.69 (0.81) and the numbers in the parentheses the standard deviations. The maximum error obtained by combining the estimated maximum errors in the various measurements was 8.4 ppm.

Tris(hydroxymethyl)aminomethane-a primary standard?

Commercially available "primary standard" grade tris(hydroxymethyl)aminomethane (THAM) may not always be of the requisite quality. Crystals of THAM can contain large amounts of occluded mother liquor. Material which has been ground, dried in vacuum, further ground, sifted through a 100-mesh sieve, and finally dried in vacuum, will approach 100% in purity.

An electrode for the coulometric generation of hydrogen ion.

The anodic generation of hydrogen ion on bright platinum in 1.0M sodium perchlorate is not quantitative owing to the formation of a chemical species With oxidizing properties, presumably a peroxydiperchlorate, but 100% current efficiency can be obtained in the anodic generation of hydrogen in 0.25M sodium hydrazinium sulphate, Na(N(2)H(5))SO(4). Five hydrogen ions are formed for each four electrons passed. The efficiency of this "hydrazine-platinum anode" has been demonstrated by the high-precision coulometric titration of tris(hydroxymethyl)aminomethane.

Location of end-points in high-precision coulometry.

A computer has been used to fit a cubic equation to experimental data obtained in the region of the end-point in high-precision coulometric titrations of 4-aminopyridine and tris(hydroxy-methyl) aminomethane. For these weak bases, the two end-points (points of inflexion calculated by setting the second derivative equal to zero) obtained by choosing first time, and secondly pH, as the independent variable, are in good agreement.