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Preparations of Tamm-Horsfall glycoprotein were examined by SDS-polyacrylamide gel electrophoresis and detection using various125I-lectins as well as Coomassie Brilliant Blue. Considerable heterogeneity of electrophoretic pattern was seen. This was not due to a genetic polymorphism. Variation in binding by Soy-bean agglutinin was also seen. This was correlated with the Sda phenotype of the individual.

SummaryUrine samples, negative for protein on ‘dipstick’ testing (< 300 mg/l), were collected from women at 28–41 weeks of pregnancy and analysed for albumin and creatinine. Compared with a non-pregnant control group, there was no significant difference in the urine albumin:creatinine ratio at 28–31, 32–35, 36–37 or 37–41 weeks. Nor was there any difference in the ratio in relation to maternal age and parity or fetal sex and birth weight. The results suggest that pregnancy in general has no effect on albumin excretion.

Background: Ovarian cancer has a high case–fatality ratio, with most women not diagnosed until the disease is in its advanced stages. The United Kingdom Collaborative Trial of Ovarian Cancer Screening (UKCTOCS) is a randomised controlled trial designed to assess the effect of screening on mortality. This report summarises the outcome of the prevalence (initial) screen in UKCTOCS. Methods: Between 2001 and 2005, a total of 202 638 post-menopausal women aged 50–74 years were randomly assigned to no treatment (control; n=101 359); annual CA125 screening (interpreted using a risk of ovarian cancer algorithm) with transvaginal ultrasound scan as a second-line test (multimodal screening [MMS]; n=50 640); or annual screening with transvaginal ultrasound (USS; n=50 639) alone in a 2:1:1 ratio using a computer-generated random number algorithm. All women provided a blood sample at recruitment. Women randomised to the MMS group had their blood tested for CA125 and those randomised to the USS group were sent an appointment to attend for a transvaginal scan. Women with abnormal screens had repeat tests. Women with persistent abnormality on repeat screens underwent clinical evaluation and, where appropriate, surgery. This trial is registered as ISRCTN22488978 and with ClinicalTrials.gov, number NCT00058032. Findings: In the prevalence screen, 50 078 (98·9%) women underwent MMS, and 48 230 (95·2%) underwent USS. The main reasons for withdrawal were death (two MMS, 28 USS), non-ovarian cancer or other disease (none MMS, 66 USS), removal of ovaries (five MMS, 29 USS), relocation (none MMS, 39 USS), failure to attend three appointments for the screen (72 MMS, 757 USS), and participant changing their mind (483 MMS, 1490 USS). Overall, 4355 of 50 078 (8.7%) women in the MMS group and 5779 of 48 230 (12·0%) women in the USS group required a repeat test, and 167 (0·3%) women in the MMS group and 1894 (3·9%) women in the USS group required clinical evaluation. 97 of 50 078 (0·2%) women from the MMS group and 845 of 48 230 (1·8%) from the USS group underwent surgery. 42 (MMS) and 45 (USS) primary ovarian and tubal cancers were detected, including 28 borderline tumours (eight MMS, 20 USS). 28 (16 MMS, 12 USS) of 58 (48·3%; 95% CI 35·0–61·8) of the invasive cancers were stage I/II, with no difference (p=0·396) in stage distribution between the groups. A further 13 (five MMS, eight USS) women developed primary ovarian cancer during the year after the screen. The sensitivity, specificity, and positive-predictive values for all primary ovarian and tubal cancers were 89·4%, 99·8%, and 43·3% for MMS, and 84·9%, 98·2%, and 5·3% for USS, respectively. For primary invasive epithelial ovarian and tubal cancers, the sensitivity, specificity, and positive-predictive values were 89·5%, 99·8%, and 35·1% for MMS, and 75·0%, 98·2%, and 2·8% for USS, respectively. There was a significant difference in specificity (p

Enhanced natriuretic response to neutral endopeptidase inhibition in patients with moderate chronic renal failure. Atrial natriuretic factor (ANF) has natriuretic, renin-suppressing and chronic hypotensive actions that may be utilized by inhibition of ANF degradation by neutral endopeptidase, E.C.24.11 (NEP). Three groups of 8 male patients [GFR 103 ± 8 (Normal), 64 ± 6 (Moderate CRF), and 16 ± 2ml/min (Severe CRF)] received 100mg i.v. bolus of the NEP inhibitor candoxatrilat or placebo in random order in a double-blind crossover study. GFR (51CR-EDTA), ERPF (125I-hippuran), ANF (IRMA), urinary cGMP (RIA) and albumin (RIA) and sodium excretion and flow rate were measured hourly for two hours before and for seven hours after candoxatrilat administration. After candoxatrilat plasma ANF rose two- to threefold from baseline, and remained elevated for 5N and 7MS hours (P < 0.01NS, P < 0.03M) associated with an immediate rise in urine cGMP excretion from 23.5N, 25.4M and 10.4s nmol/hr (base) to 51.7N, 73.8M and 27.5s(peak) lasting 7N,M,S hours P < 0.0lN,M,S). There was a marked natriuresis in all three groups, the cumulative sodium excretion at seven hours post-candoxatrilat being 104N, 140M, 102s mmol (P < 0.05N,M,S). This was greatest in those with moderate CRF (moderate CRF vs. normal, P = 0.036, moderate vs. severe CRF, P = 0.01, normal vs. severe CRF, P = 0.74). Following candoxatrilat there was a near doubling of the urine flow rate (P < 0.01N,S, P < 0.02M). Urine albumin excretion increased in patients with renal failure (P < 0.01), but there was no change in GFR, ERPF or systemic blood pressure. We conclude that the marked natriuretic effects of acute NEP inhibition seen in normal subjects are enhanced in the presence of moderate CRF and sustained even in severe renal impairment.

1. Haemaccel is a synthetic polymer of partially degraded gelatin and a widely used plasma volume expander. 2. The effect of a 17.5 g infusion of Haemaccel on protein excretion was investigated in four normal subjects. 3. The urinary excretion of two low molecular weight proteins, retinol-binding protein and β2-microglobulin, increased 1000- and 500-fold respectively above the values found after administration of saline as a control. The urinary excretion of albumin did not change significantly (P > 0.5). 4. In the hour after Haemaccel administration the excretion of the two low molecular weight proteins approached at least 50% of a predicted filtered load. 5. This effect of Haemaccel may be due to inhibition of proximal tubular uptake or transport of the two proteins. Absence of any effect on albumin excretion suggests alternative mechanisms for its tubular reabsorption. 6. Haemaccel may be a valuable new agent for the study of renal tubular protein metabolism.

The Tamm–Horsfall glycoprotein prepared by salt precipitation from urine was found to comprise a heterogeneous collection of aggregates. These could be disaggregated with 8m-urea, following which chromatography on a column of Bio-Gel A.15m yielded a homogeneous glycoprotein of mol.wt. 73000 together with several unidentified impurities. Gel filtration of normal plasma showed the glycoprotein to exist predominantly in a form that is eluted identically with the purified preparation. In one case, material of higher molecular weight was also detected. The purified glycoprotein was used to develop a rapid specific radioimmunoassay for its measurement in human serum or plasma by the use of the Tamm–Horsfall glycoprotein, labelled with 125I by the chloramine-t method as the tracer, an antiserum raised in rabbits, and separation of the bound and free fractions by a second antibody covalently linked to magnetizable particles. Parallelism was demonstrated between the standard preparation and samples. Recovery of added standard to serum varied between 99 and 109%. Total assay time was less than 4h with an intra-assay and inter-assay coefficient of variation of less than 10%. There were no significant differences in the ranges covered with regard to either age or sex, and no circadian rhythm was observed in normal subjects. A physiological range of 70–540ng/ml was established based on serum samples from 95 subjects with normal renal function, as defined by their serum creatinine and urea concentrations. No Tamm–Horsfall glycoprotein was detected in the serum of six anephric patients.

A rapid, specific radioimmunoassay has been used to measure Tamm-Horsfall glycoprotein (TH glycoprotein) in urine. The apparent concentration increased with increasing dilution of urine in water, reaching a plateau at 1 in 20. This increase was greater the higher the osmolality and TH glycoprotein concentration and the lower the pH of the original sample. A dilution of 1 in 100 was chosen for routine assay. Whole urine was centrifuged and the dissolved precipitate and supernatant assayed to quantify the proportion of TH glycoprotein of TH glycoprotein initially present in highly aggregated form. This correlated positively and significantly with increasing osmolality, decreasing pH and increasing TH glycoprotein concentration. When the urine was diluted 1 in 100 in water, no TH glycoprotein was precipitated by centrifugation and the measured concentrations were unaffected by alterations of urine pH or calcium concentration or by addition of sodium dodecyl sulphate. Parallelism was demonstrated between the diluted samples and the disaggregated standard preparation. Recovery of added standard to diluted urine varied between 96 and 114%. The apparent concentration of TH glycoprotein in neat or diluted urine was not affected by freezing or by storage at 4 degrees C or room temperature for at least 2 days. A physiological range for the urinary excretion rate was established as 22-56 mg/24 h, based on samples from 29 individuals with normal renal function, as defined by their creatinine clearance. There was no significant correlation between serum concentrations of TH glycoprotein and its urinary excretion rate, nor between urinary excretion rate and creatinine clearance.

Cyclosporin A (CyA) is widely used as an immunosuppressant following organ transplantation and in the treatment of various autoimmune disorders. A major disadvantage is its nephrotoxicity which is probably of multifactorial origin, involving acute, reversible haemodynamic changes and irreversible tubulointerstitial injury and focal glomerulosclerosis (Cohen et al, 1984; Klintmalm et al, 1984; Myers et al, 1984; Palestine et al, 1986). There is no satisfactory animal model for CyA nephrotoxicity and its assessment in CyA treated renal transplant recipients is complicated by the coexistence of other renal disorders. For these reasons, we have chosen to study a group of patients being treated with long-term CyA for an autoimmune disorder, primary biliary cirrhosis (PBC).

A liquid-phase fluoroimmunoassay has been developed for the measurement of β-2-microglobulin in undiluted serum or plasma. Protein labelled with fluorescein-isothiocyanate at a molar ratio of 1:2 respectively is employed as a tracer together with an antiserum to β-2-microglobulin raised in a sheep. Separation is achieved by means of rabbit anti-sheep immunoglobulin G and, following precipitation of the bound fraction by centrifugation, the free fraction together with any potentially interfering factors is removed in the supernatant. Finally the precipitate is dissolved and the fluorescence measured. The assay is simple and rapid in that all reactants, including the second antibody, can be added at the start of the assay and equilibrium is attained within 60 min. The assay is reproducible and sufficiently sensitive to allow measurement of normal serum levels and has a wide range avoiding the need for sample dilution. Results correlated well with those of an established radioimmunoassay. © 1985, Association for Clinical Biochemistry. All rights reserved.

In vitro segregation of the metanephric nephron was examined using three probes for the main segments: fluorochrome-conjugated wheat germ agglutinin (WGA) binding to the glomerular epithelial surface, an antiserum against the brush-border antigens (BB) of the proximal tubules, and an antiserum against the Tamm-Horsfall glycoprotein (TH) of the distal tubules. In vivo , these markers appeared sequentially on Days 13 to 15. The same sequence was obtained in experimental recombinants of the metanephric mesenchyme and its inductor. When the inductor was removed after a 24 hr initial transfilter contact with the mesenchyme, segregation was similarly observed after subculture of the isolated mesenchyme. Hence, the sequential, multiphase differentiation of the nephron is initiated during a short induction period.