Renal tubular proteinuria in patients with irritable bowel syndrome.

OBJECTIVE: Irritable bowel syndrome (IBS) is a common condition that is poorly understood. We have previously demonstrated tubular protinuria in patients with inflammatory bowel disease. This study examined whether tubular proteinuria was a feature of IBS. METHODS: Eighty control subjects (male:female, 28:52; age range 20-65 years) and 21 patients with IBS (male:female, 9:12; age range 16-64 years) (not significant) were recruited. Patients with known renal disease, hypertension, diabetes or microbiological evidence of urinary infection were excluded. The IBS patients all fulfilled the ROME II criteria. None had preceding gastroenteritis. Urinary alpha1-microglobulin (alpha1-M) was measured in a second-voided morning urine sample and corrected for urinary concentration by measurement of creatine. Blood samples were analysed for haematochemical indices including C-reactive protein. Statistical analysis was by unpaired t test. RESULTS: None of the IBS patients were reclassified with inflammatory bowel disease over a 5-year follow up period. All had normal haematochemical parameters. Mean +/- standard deviation urinary alpha1-M concentrations were significantly higher in IBS patients than controls (IBS patients, 1.17 +/- 0.65 mg/mmol; controls, 0.75 +/- 0.36 mg/mmol; P < 0.01) and exceeded 1.5 mg/mmol (the upper reference limit) in seven patients. There was no difference in urinary alpha1-M concentrations in the diarrhoea-predominant and constipation-predominant groups (mean +/- standard deviation, 1.342 +/- 0.65 versus 0.76 +/- 0.48 mg/mmol; P = 0.062). CONCLUSIONS: Urinary alpha1-M concentration is commonly increased in IBS, suggesting the presence of renal proximal tubular injury.

Renal tubular injury is present in acute inflammatory bowel disease prior to the introduction of drug therapy.

BACKGROUND: 5-aminosalicylic acid (5-ASA) has been associated with renal complications in inflammatory bowel disease. Renal function is typically monitored using serum creatinine; however, significant disease may predate increases in creatinine. AIMS: To identify whether markers of early renal disease (urinary albumin, alpha-1-microglobulin [alpha-1-M] and N-acetyl-beta-D-glucosaminidase [NAG], and serum cystatin C) are useful in the assessment of renal function in inflammatory bowel disease patients receiving 5-ASA. METHODS: Twenty-one patients with a new diagnosis of inflammatory bowel disease were investigated. Samples were taken at diagnosis, and at 3-monthly intervals after the commencement of 5-ASA, for 1 year. RESULTS: Mean creatinine clearance was 100 mL/min and did not change following treatment. Inflammatory bowel disease was not associated with albuminuria. Urinary N-acetyl-beta-D-glucosaminidase and alpha-1-microglobulin at diagnosis were increased in 10 (48%) and 11 (52%) patients, respectively: treatment was not associated with consistent changes in urinary protein excretion. There was a significant correlation between cystatin C and creatinine clearance both at diagnosis (r=-0.533, P=0.0275) and combining the initial and follow-up data (r=-0.601, P < 0.01), but not between creatinine and creatinine clearance (P > 0.05). CONCLUSIONS: Tubular proteinuria is an extra-intestinal manifestation of inflammatory bowel disease irrespective of 5-ASA treatment. Tubular proteins are not useful predictors of an adverse renal response to 5-ASA. Serum cystatin C may be an improved marker of glomerular filtration rate in this setting.

Metabolic bone disease is present at diagnosis in patients with inflammatory bowel disease.

AIM: To establish whether bone disease is present at diagnosis in inflammatory bowel disease and to identify contributory metabolic abnormalities. METHODS: Newly diagnosed patients with inflammatory bowel disease (19 males, 15 females; mean age, 44 years; range, 17-79 years; 23 ulcerative colitis, 11 Crohn's disease) were compared against standard reference ranges and a control group with irritable bowel syndrome (eight males, 10 females; mean age, 40 years; range, 19-64 years). Bone mineral density (g/cm2, dual-energy X-ray absorptiometry: lumbar spine and femoral neck) and biochemical bone markers were measured. RESULTS: Femoral neck bone mineral density, T- and Z-scores (mean +/- s.d., respectively) were lower in inflammatory bowel disease patients than in irritable bowel syndrome controls (0.78 +/- 0.12 vs. 0.90 +/- 0.16, P = 0.0046; - 0.88 +/- 0.92 vs. 0.12 +/- 1.17, P = 0.0018; - 0.30 +/- 0.89 vs. 0.61 +/- 1.10, P = 0.0030). Lumbar spine bone mineral density and T-scores were also significantly lower in patients than controls (0.98 +/- 0.15 vs. 1.08 +/- 0.13, P = 0.0342; - 1.05 +/- 1.39 vs. - 0.14 +/- 1.19, P = 0.0304). Compared with controls, the urinary deoxypyridinoline : creatinine ratio was increased (7.66 vs. 5.70 nmol/mmol, P = 0.0163) and serum 25-hydroxy vitamin D was decreased (18.7 vs. 28.5 micro g/L, P = 0.0016); plasma osteocalcin and serum parathyroid hormone did not differ (P > 0.05). CONCLUSIONS: The bone mineral density is reduced at diagnosis, prior to corticosteroid treatment, in both Crohn's disease and ulcerative colitis. Our data suggest that this is attributable to increased resorption rather than decreased bone formation.

Glycoprotein hormone alpha-subunit production and plurihormonality in human corticotroph tumours--an in vitro and immunohistochemical study.

Glycoprotein hormone alpha-subunit (alpha SU) is a recognized product of clinically non-functioning, glycoprotein hormone-secreting and somatotroph adenomas but has not been studied systematically in corticotroph tumours. We have performed immunohistochemistry for alpha SU in a consecutive series of four corticotroph tumours causing Nelson's syndrome, three corticotroph macroadenomas, 12 corticotroph microadenomas and one adrenocorticotrophin-secreting bronchial carcinoid tumour. In addition we have assessed alpha SU secretion in vitro in corticotroph adenomas from two subjects with Cushing's disease and two subjects with Nelson's syndrome. Immunohistochemistry, performed after microwave treatment of sections to enhance antigen retrieval, demonstrated alpha SU positivity in 3/4 Nelson's tumours, 2/3 corticotroph macroadenomas, 7/12 microadenomas and one bronchial carcinoid. Eight of the 13 tumours positive for alpha SU were also immunostained after microwave pretreatment of sections for thyrotrophin (six positive), follicle-stimulating hormone (four positive), luteinizing hormone (three positive), beta-chorionic gonadotrophin (five positive), growth hormone (three positive) and prolactin (two positive) immunoreactivity. In vitro cell cultures of all four tumours studied secreted adrenocorticotrophin and three secreted alpha SU, with the variable presence of luteinizing hormone, follicle-stimulating hormone, thyrotrophin, growth hormone and prolactin, in basal culture. The alpha SU secretion was augmented by phorbol ester (160 +/- 15%, SEM, n = 3 wells; p < 0.01) and 8-bromo-cAMP (138 +/- 8%; p < 0.05) in one tumour. These data indicate that plurihormonality and, in particular, alpha SU elaboration and secretion by corticotroph tumours is more common than hitherto recognized. Possible mechanisms include abnormal or deregulated gene expression, autocrine or paracrine effects or a stem cell origin of tumour.(ABSTRACT TRUNCATED AT 250 WORDS)

Use of an immunoradiometric assay and a radioimmunoassay for the detection of free beta-human chorionic gonadotropin.

An immunoradiometric assay and a radioimmunoassay (RIA) were used to quantitate human chorionic gonadotropin (hCG) in the sera of ten pregnant women at term and of six women with gestational trophoblastic neoplasia. The two techniques show good correlation (Pearson correlation coefficient .96) in the assay of pregnancy serum. Because only the RIA, and not the immunoradiometric assay, measures the free beta-subunit of hCG, a comparison of the results obtained by the two immunoassay methods permits a semi-quantitative assessment of the free beta-subunit. The numerical results may not reflect the actual concentration of free beta-subunit in that two different immunoassay methods are used.

Prognosis for the infertile couple.

PIP: Analysis of conception rates for infertile couples based on the life table method of analysis of data is presented. 60% of the couples conceived within 3 years if the wife was under 25, had been infertile for less than 2 years, and had a normal culdoscopic examination. Women over 35, infertile for 6 or more years, with a history of pelvic infection or laparotomy and abnormal culdoscopic examination had only a 25-38% conception rate within 3 years.^ieng

Do the results of semen analysis predict future fertility? A survival analysis study.

The authors examined the results of the initial semen analysis from 1089 couples in an infertility clinic. The distributions of the values for various semen variables among couples who remained infertile were very similar to those among couples who later conceived. A cutoff point was selected in each pair of distributions to compare the cumulative probability of conception for couples with higher and lower results. The authors took into account the varying times to conception or loss to follow-up by using life table analysis. No statistically significant differences were found at the P = 0.05 level of significance. Cox's univariate and multiple regression models were then used to investigate the relationship between various semen characteristics and future fertility. Finding no significant influence of any semen characteristic on the cumulative probability of conception, the authors believe that using specific values of the semen analysis to estimate the potential for fertility of infertile couples is not useful.

Cryopreservation of mouse 2-cell embryos and ova by vitrification: methodologic studies.

Cryopreservation of unfertilized mouse ova and 2-cell embryos by a vitrification technique was examined. Survival was defined by development to the hatching blastocyst stage after in vitro fertilization. With 19 embryos at the 2-cell stage, the authors obtained 100% morphologic survival and 89% development to hatching blastocyst stage. To define the optimal conditions for vitrification of ova, the authors treated a total of 845 unfertilized ova. In experiments done at 0 degree C, the concentration of vitrification solution (VS1) and the length of exposure of ova to VS1 both had significant (P less than 0.01) effects on survival. The mean survival rate for controls in ten experiments was 52%. VS1 100% or 90% in HEPES buffered saline and 10 minutes' exposure yielded rates that did not differ significantly from controls. Significantly lower survival rates followed the use of 70 and 80% solution and exposure for 5, 15, 20, or 30 minutes. Thus, under these conditions, exposure of unfertilized mouse ova to VS1 and cooling to 0 degree C did not interfere with in vitro fertilization and development of embryos. However, in five experiments in which a total of 101 ova were plunged into liquid nitrogen after treatment with VS1 under the optimal conditions, none could be fertilized in vitro.

Cryopreservation of embryos and ova.

Development of techniques for cryopreservation of embryos of several species, principally the mouse, laid the foundation for cryopreservation of human embryos. As IVF has become more widely available and the need for the cryopreservation of human embryos has become apparent, pressure for technical development has increased. The ideal method would be simple, inexpensive, and effective. The most effective method for cryopreservation of early human embryos, such as those at the 1-cell pronuclear stage and up to the 4-cell stage, now appears to be stepwise cooling in 1,2-propanediol with sucrose in plastic ministraws. The preferred method for intermediate stage embryos uses DMSO with cooling and thawing at slow rates in a programmed biologic freezer. For the human blastocyst, slow cooling in glycerol and rapid thawing is the only method reported with survival rates comparable to those achieved for intermediate stage embryos using DMSO. The rates of survival from freezing and thawing blastocysts are not sufficiently high, however, to justify the losses associated with prolonged in vitro incubation. Even at the current level of technical achievement, cryopreservation of human embryos provides the clearest opportunity to improve the clinical results obtained with IVF. Research now underway in the modification of methods for vitrification and ultrarapid freezing holds promise for both simplification of technology and improvement of outcome. In view of legal and ethical considerations involved in embryo preservation, the desirability of ova preservation is widely accepted. Although a small number of human unfertilized mature ova have been cryopreserved using various methods, success rates are still low. Methods for the cryopreservation of eggs should be developed, but these methods probably should be proved by animal experiments to be safe, especially with regard to genetic damage, before a policy of transfer of embryos derived from frozen-thawed human ova is applied on a large scale.

Endometriosis: studies of a method for the design of a surgical staging system.

This study develops a method of identifying factors that predict pregnancy rates in patients with endometriosis. In 123 women, 60% had adhesions, 89% had implants, and 29% had endometriomas. The most common lesions were cul-de-sac implants (60%), ovarian implants (58%), and ovarian adhesions (55%). With no treatment, the life-table-estimated 3-year pregnancy rate was 40%; with oral contraceptives, 33%; and with surgery, 53%. Clustering techniques suggested new combinations of variables to be tested. We identified structures commonly involved simultaneously in a given patient, defined subgroups based on type of lesion, and developed a method to determine which factors were important in predicting outcome. In our patients, neither of two current methods of endometriosis staging predicted outcome. Further testing of the model systems suggested by the data may enable us to develop a staging system more predictive of pregnancy rates in endometriosis patients.

Local anesthesia with conscious sedation for laparoscopic intrafallopian transfer.

Local anesthesia with conscious sedation is well accepted by patients and provides scheduling flexibility, cost containment, patient safety, and ease of recovery. We believe the technique should be offered to selected patients undergoing intrafallopian transfer. By adhering to specific guidelines for surgical technique and monitoring, the procedure is a safe and acceptable alternative to general anesthesia for laparoscopic intrafallopian transfers.

Improved prediction of postovulatory day using temperature recording, endometrial biopsy, and serum progesterone.

The use of basal body temperature (BBT) recording and a single progesterone (P) level at the time of the endometrial biopsy in the late luteal phase improved our ability to predict the onset of the next menstrual period (NMP) and determine the postovulatory day (POD) in 124 regularly menstruating infertile women. We determined BBT shift using a microcomputer program, analyzed P levels by radioimmunoassay, and evaluated endometrial biopsies both prospectively (blinded) and retrospectively (with knowledge of the other variables). Serum P levels were within the normal range for the luteal phase and prospective and retrospective histological diagnoses closely agreed (82% within 2 days). The best correlation with the NMP was the BBT shift (r = 0.493) followed by P (r = 0.426) and prospective histologic dating (r = 0.390). Multiple regression analysis confirmed that use of all of the variables markedly improved the ability to estimate the POD (R2 = 0.51).

Thyroid function tests: often justified in the acutely ill.

It is claimed that inappropriate requesting of thyroid function tests (TFTs) is common in acutely ill patients. Consecutive inpatient TFTs (n = 129) were assessed in relation to clinical history and common symptoms and signs of thyroid disease. Requests were justified in 69% of cases, most commonly on the basis of atrial fibrillation and/or tachycardia. There were no clear reasons for requesting TFTs in the remaining cases, although the yield of abnormal results in these patients was similar to that in those with justified requests. Thyroid stimulating hormone (TSH) concentration was increased (median 7.5 mU/L, range 4.8-38.6 mU/L) in 22 patients, six of whom had biochemical and/or clinical evidence of hypothyroidism (previously undiagnosed) and five of whom had pre-existing hypothyroidism. Of the remaining 11 patients with increased TSH levels, three were confirmed to have compensated hypothyroidism; non-thyroidal illness (NTI) (including the effect of drugs) accounted for four cases. In four patients (one of whom died during the admission) follow-up was not possible. Of six patients with reduced TSH concentration (range <0.05-0.35 mU/L), one was thyrotoxic on carbimazole, one was receiving thyroxine for hypothyroidism, one had NTI and three were lost to follow-up (two of whom died during their admission). Manifestations of thyroid disease are protean and often subtle, and TFTs are thus clinically justified in many unwell inpatients. Although NTI contributes to some cases of abnormal TSH levels, a significant number of TFT abnormalities are consistent with underlying thyroid abnormality requiring investigation/treatment.

Urine-free cortisol excretion: evidence of sex-dependence.

Measurement of urine-free (unconjugated) cortisol (UFC) excretion is widely used in the investigation of hypercortisolaemia. We have measured 24 h UFC excretion in normal healthy individuals using a radioimmunoassay (RIA) method claimed to be suitable for unextracted urine. Significantly higher rates of excretion were found in a group of 15 men compared with a group of 18 women, with median values of 230 (range 145-334) and 149 (range 67-315) nmol/24 h, respectively (P < 0.005). This method was used to reanalyse the urine samples after extraction with dichloromethane. Although values were significantly lower than those found with unextracted urine (P < 0.001), the male:female difference remained with median values of 140 (range 96-295) and 112 (range 29-196) nmol/24 h, respectively (P < 0.02). Rates of UFC excretion were measured on the same dichloromethane-extracted urine samples using a second, different RIA, which again demonstrated the male:female difference with median values of 151 (range 116-302) and 109 (range 36-205) nmol/24 h, respectively (P < 0.001). There was no significant difference between these values and those obtained with extracted urine in the first assay. The higher rates of UFC excretion in men compared to women does not appear to be due to the presence of interfering compounds since the difference is also present using extracted urine samples and with two methods using different antibodies. These results should be borne in mind by laboratories when interpreting UFC results.

Stability of parathyroid hormone ex vivo in haemodialysis patients.

BACKGROUND: The stability of parathyroid hormone (PTH) in blood ex vivo is a significant practical problem for laboratories and clinicians. Several studies have suggested that PTH is more stable in blood collected into a potassium edetate (EDTA) preservative. METHODS: To confirm that this was applicable to renal dialysis patients using our assay (Nichols chemiluminescence), we examined PTH stability in 13 patients with end-stage renal failure using three different blood collection tubes. RESULTS: PTH remained stable in EDTA plasma for up to 48 h at room temperature. PTH was significantly reduced in serum collected into plain tubes after 2 h, and after 4 h in serum collected into serum separator tubes, at room temperature. CONCLUSION: In the assessment of renal osteodystrophy, the use of EDTA plasma can confer significant benefit, especially in busy laboratories where rapid frozen separation of blood may be hard to achieve.

Alkaline phosphatase activity measurement in the UK by AMP-buffered methods: an appraisal of current practice.

Most UK clinical laboratories use alkaline phosphatase (ALP) methods similar to that proposed by the International Federation of Clinical Chemistry (IFCC), based on the use of 2-amino-2-methyl-1-propanol (AMP) buffer. We present evidence of significant differences in results produced by apparently similar commercial ALP methods using an AMP buffer. We compared Bayer DAX, Dade Dimension and Boehringer Mannheim Hitachi 717 methods. Boehringer and Dade results were higher than Bayer results (Bland and Altman analysis, log transformed data): Boehringer (+23.0%, limits of agreement 1.16-1.31 times Bayer); Dade (+21.9%, limits of agreement 1.13-1.32 times Bayer). Biases were predominantly due to differences in reagents rather than analyser characteristics. Compared to a reagent system prepared exactly as described by the IFCC, Bayer was sub-optimal and Dade and Boehringer methods produced results higher than the IFCC method. Reference ranges and results on patients' samples by the various methods showed large differences but no clinically significant difference was observed in external quality assessment schemes either between Bayer and Boehringer or against method means. Apparently similar methods produce different results in patients' sera: external quality assessment schemes are not useful in highlighting these differences.

Estimating glomerular filtration rate: comparison of the CKD-EPI and MDRD equations in a large UK cohort with particular emphasis on the effect of age.

BACKGROUND: The chronic kidney disease (CKD)-Epidemiology Collaboration (CKD-EPI) equation was developed to address the underestimation of measured glomerular filtration rate (GFR) by the Modification of Diet in Renal Disease (MDRD) equation at levels >60 mL/min/1.73 m(2). AIM: To assess the impact of the CKD-EPI equation on the estimation of GFR in a large adult UK population (n = 561,400), particularly looking at the effect of age. DESIGN: Serum creatinine results (ID-MS-aligned enzymatic assay) were extracted from the pathology database during 1 year on adult (≥ 18 years) patients from primary care. METHODS: The first available creatinine result from 174,448 people was used to estimate GFR using both equations and agreement assessed. RESULTS: Median CKD-EPI GFR was significantly higher than median MDRD GFR (82 vs. 76 mL/min/1.73 m(2), P < 0.0001). Overall mean bias between CKD-EPI and MDRD GFR was 5.0%, ranging from 13.0% in the 18-29 years age group down to -7.5% in those aged ≥ 90 years. Although statistically significant at all age groups the difference diminished with age and the agreement in GFR category assignment increased. Age-adjusted population prevalence of CKD Stages 3-5 was lower by CKD-EPI than by MDRD (4.4% vs. 4.9%). CONCLUSION: CKD-EPI produces higher GFR and lower CKD estimates, particularly among 18-59 year age groups with MDRD estimated GFRs of 45-59 mL/min/1.73 m(2) (Stage 3A). However, at ages >70 years there is very little difference between the equations, and among the very elderly CKD-EPI may actually increase CKD prevalence estimates.