Is 125I iothalamate an ideal marker for glomerular filtration?

Is 125I iothalamate an ideal marker for glomerular filtration? The triiodinated angiographic contrast medium, iothalamate, has (usually labelled 125I) been used extensively as a marker for glomerular filtration. We have studied the renal handling of 125I iothalamate (IOT) in vivo and in vitro in several species. In renal cortical slices from chicken, rabbit, rat, and monkey, the tissue-to-medium ratio of IOT was twice that of 51Cr-EDTA (EDTA) at 37°C; a difference that was abolished at 0°C and markedly reduced by added o-iodohippurate or iodipamide. In five chickens the steady-state renal clearance of IOT (CIOT) was twice (P < 0.05) that of EDTA (CEDTA) or 3H inulin (C1); a difference that was abolished by administration of 100 mg/kg/hr of novobiocin, an organic anion transport inhibitor. CEDTA was similar to C1 before as well as after transport inhibition. Utilizing the Sperber technique the mean apparent tubular excretion fraction (ATEF) of IOT was 8%, while that of EDTA was 1% (P < 0.01; N = 10). After novobiocin coinfusion (new steady-state) ATEFIOT was significantly reduced (P < 0.01) and not different from that of EDTA (-1%). In the same animals the total urinary recovery of IOT was 84 and 57% (P < 0.01) before and after novobiocin, respectively, while corresponding values for EDTA was unchanged by the inhibitor. In seven rats the renal extraction of IOT was reduced from 29 to 17% (P < 0.05) by coinfusion of probenecid (5 mg/kg/hr). Corresponding extractions were 82 to 34% (P < 0.005) and 22% (unchanged) for PAH and EDTA, respectively. In six healthy volunteers the renal clearance of unlabelled IOT (HPLC method) equated that of creatinine but exceeded that of inulin with 38% (P < 0.01). This difference was reduced 34% (P<0.05) by probenecid (1 g i.v.). In nineteen patients with a single or two kidneys the average plasma clearance (single injection technique; slope-intercept method) of IOT was 13% higher than that of EDTA (P < 0.001); a difference which was significantly (P < 0.01) reduced to half after pretreatment with probenecid (1 g i.v.); in some patients this difference was marked. The results show that IOT is subject to a significant and in some cases marked renal tubular secretion in chicken, rats, and humans. IOT, therefore, is not an ideal marker for glomerular filtration.Le 125I iothalamate est-il un marqueur idéal de la filtration glomérulaire? L'iothalamate, un produit de contraste angiographique tri-iodé a été largement utilisé (habituellement marqué à 125I) comme marqueur de la filtration glomérulaire. Nous avons étudié l'excrétion rénale du 125I iothalamate (IOT) in vivo et in vitro dans différentes espèces. Dans des tranches corticales de rein de poulet, de lapin, de rat, et de singe, le rapport tissu sur milieu de l'IOT était le double de celui du 51Cr-EDTA (EDTA) à 37°C; une différence abolie à 0°C et réduite de façon marquée par l'addition de O-iodohippurate ou d'iodipamide. Chez cinq poulets la clearance rénale à l'équilibre d'IOT (CIOT) était le double (P < 0,05) de celle de l'EDTA (CEDTA) ou de 3H inuline (CI); une différence abolie par l'administration de 100 mg/kg/hr de novobiocine, un inhibiteur du transport des anions organiques. CEDTA était identique à CI avant comme après l'inhibition du transport. En utilisant la technique de Sperber, la fraction d'excrétion tubulaire apparente moyenne (ATEF) de l'IOT était de 8%, alors que celle de l'EDTA était de 1% {P < 0,01; N = 10). Après coperfusion de novobiocine (nouvel équilibre) ATEFIOT était significativement réduite (P < 0,01) et non différente de celle de l'EDTA (- 1%). Chez les mêmes animaux, la récupération urinaire totale d'IOT était de 84 et 57% (P < 0,01) avant et après novobiocine, respectivement, alors que les valeurs correspondantes pour l'EDTA étaient inchangées par l'inhibiteur. Chez sept rats, l'extraction rénale d'IOT était réduite de 29 à 17% (P < 0,05) par coperfusion de probénécide (5 mg/kg/hr). Les extractions correspondant étaient de 82 à 34% (P < 0,005) et de 22% (inchangées) pour le PAH et l'EDTA, respectivement. Chez six volontaires sains, la clearance rénale de l'IOT non marqué (méthode HPLC) était égale à celle de la créatinine mais dépassait celle de l'inuline de 38% (P < 0,01). Cette différence était réduite de 34% (P < 0,05) par le probénécide (1 g i.v.). Chez dix-neuf malades avec un ou deux reins, la clearance plasmatique moyenne (technique par injection unique; méthode d'interception de la courbe) de l'IOT était 13% plus élevée que celle de l'EDTA (P < 0,01); une différence qui était significativement (P < 0,01) réduite de moitié après prétraîtement par le probénécide (1 g i.v.); chez certains malades cette différence était marquée. Ces résultats montrent que l'IOT est sujet à une sécrétion tubulaire rénale significative et parfois marquée chez le poulet, le rat, et l'homme. L'IOT n'est donc pas un marqueur idéal de la filtration glomérulaire

Microbiology profile in women with pelvic inflammatory disease in relation to IUD use.

OBJECTIVE: To study the microbial characteristics of patients with pelvic inflammatory disease (PID) and the possible impact of an intrauterine device (IUD) on the microbial environment in women presenting with PID. METHODS: Case-control study, investigating 51 women with acute PID and 50 healthy women. Endocervical specimens for microbiological investigation were obtained at gynaecological examination. RESULTS: IUD users with PID had significantly more Fusobacteria spp. and Peptostreptococcus spp. than non-IUD users with PID. The finding of combinations of several anaerobic or aerobic microbes was associated with a significantly increased risk of PID and with complicated PID. In IUD users, the combinations of several anaerobic/aerobic microbes were associated with an increased risk of PID, irrespective of duration of IUD use. Long-term IUD use appeared to be associated with an increased risk of a PID being complicated. CONCLUSION: The finding of several anaerobic or aerobic microbes appears to be associated with PID in users of IUD

Reduced natriuretic response to acute sodium loading in COMT Gene deleted mice

BACKGROUND: The intrarenal natriuretic hormone dopamine (DA) is metabolised by catechol-O-methyltransferase (COMT) and monoamine oxidase (MAO). Inhibition of COMT, as opposed to MAO, results in a potent natriuretic response in the rat. The present study in anaesthetized homozygous and heterozygous COMT gene deleted mice attempted to further elucidate the importance of COMT in renal DA and sodium handling. After acute intravenous isotonic sodium loading, renal function was followed. RESULTS: COMT activity in heterozygous mice was about half of that in wild type mice and was zero in the homozygous mice. MAO activity did not differ between the genotypes. Urinary sodium excretion increased 10-fold after sodium loading in wild type mice. In heterozygous and homozygous mice, the natriuretic effects of sodium loading were only 29 % and 39 %, respectively, of that in wild type mice. Arterial pressure and glomerular filtration rate did not differ between genotypes. Baseline norepinephrine and DA excretions in urine were elevated in the homozygous, but not in heterozygous, COMT gene deleted mice. Urinary DA excretion increased after isotonic sodium loading in the wild type mice but not in the COMT gene deleted mice. CONCLUSIONS: Mice with reduced or absent COMT activity have altered metabolism of catecholamines and are unable to increase renal DA activity and produce normal natriuresis in response to acute sodium loading. The results support the hypothesis that COMT has an important role in the DA-mediated regulation of renal sodium excretion

A Case of Oral-contraceptive Related Ischemic Colitis in Young Woman

Ischemic colitis is generally considered a disease of the elderly. The causes of ischemic colitis include low-flow states due to cardiac dysfunction or hypovolemia and certain medications including estrogen. Here we report a case of ischemic colitis in a 26-year-old woman. She had no specific medical history except taking oral-contraceptives for a long time. The mechanism of estrogen-induced ischemic colitis is not clearly understood. But we recommend that oral-contraceptives should be considered as a cause of ischemic colitis in young women

The impact of different GFR estimating equations on the prevalence of CKD and risk groups in a Southeast Asian cohort using the new KDIGO guidelines

<p>Abstract</p> <p>Background</p> <p>Recently, the Kidney Disease: Improving Global Outcomes (KDIGO) group recommended that patients with CKD should be assigned to stages and composite relative risk groups according to GFR (G) and proteinuria (A) criteria. Asians have among the highest rates of ESRD in the world, but establishing the prevalence and prognosis CKD is a problem for Asian populations since there is no consensus on the best GFR estimating (eGFR) equation. We studied the effects of the choice of new Asian and Caucasian eGFR equations on CKD prevalence, stage distribution, and risk categorization using the new KDIGO classification.</p> <p>Methods</p> <p>The prevalence of CKD and composite relative risk groups defined by eGFR from with Chronic Kidney Disease-Epidemiology Collaboration (CKD-EPI); standard (S) or Chinese(C) MDRD; Japanese CKD-EPI (J-EPI), Thai GFR (T-GFR) equations were compared in a Thai cohort (n = 5526)</p> <p>Results</p> <p>There was a 7 fold difference in CKD_3-5prevalence between J-EPI and the other Asian eGFR formulae. CKD_3-5prevalence with S-MDRD and CKD-EPI were 2 - 3 folds higher than T-GFR or C-MDRD. The concordance with CKD-EPI to diagnose CKD_3-5was over 90% for T-GFR or C-MDRD, but they only assigned the same CKD stage in 50% of the time. The choice of equation also caused large variations in each composite risk groups especially those with mildly increased risks. Different equations can lead to a reversal of male: female ratios. The variability of different equations is most apparent in older subjects. Stage G3aA1 increased with age and accounted for a large proportion of the differences in CKD_3-5between CKD-EPI, S-MDRD and C-MDRD.</p> <p>Conclusions</p> <p>CKD prevalence, sex ratios, and KDIGO composite risk groupings varied widely depending on the equation used. More studies are needed to define the best equation for Asian populations.</p

Measuring Residual Renal Function in Hemodialysis Patients without Urine Collection

This is the peer reviewed version of the following article: Wong, J., Kaja Kamal, R. M., Vilar, E. and Farrington, K. (2017), 'Measuring Residual Renal Function in Hemodialysis Patients without Urine Collection', Seminars in Dialysis, Vol. 30 (1): 39–49, which has been published in final form at doi: 10.1111/sdi.12557. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving. © 2016 Wiley Periodicals, Inc.Many patients on hemodialysis retain significant residual renal function (RRF) but currently measurement of RRF in routine clinical practice can only be achieved using inter-dialytic urine collections to measure urea and creatinine clearances. Urine collections are difficult and inconvenient for patients and staff, and therefore RRF is not universally measured. Methods to assess RRF without reliance on urine collections are needed since RRF provides useful clinical and prognostic information and also permits the application of incremental hemodialysis techniques. Significant efforts have been made to explore the use of serum based biomarkers such as cystatin C, β-trace protein and β2 -microglobulin to estimate RRF. This article reviews blood-based biomarkers and novel methods using exogenous filtration markers which show potential in estimating RRF in hemodialysis patients without the need for urine collection.Peer reviewedFinal Accepted Versio

Temporal changes in key maternal and fetal factors affecting birth outcomes: A 32-year population-based study in an industrial city

<p>Abstract</p> <p>Background</p> <p>The link between maternal factors and birth outcomes is well established. Substantial changes in society and medical care over time have influenced women's reproductive choices and health, subsequently affecting birth outcomes. The objective of this study was to describe temporal changes in key maternal and fetal factors affecting birth outcomes in Newcastle upon Tyne over three decades, 1961–1992.</p> <p>Methods</p> <p>For these descriptive analyses we used data from a population-based birth record database constructed for the historical cohort <b>Pa</b>rticulate <b>M</b>atter and <b>P</b>erinatal <b>E</b>vents <b>R</b>esearch (PAMPER) study. The PAMPER database was created using details from paper-based hospital delivery and neonatal records for all births during 1961–1992 to mothers resident in Newcastle (out of a total of 109,086 singleton births, 97,809 hospital births with relevant information). In addition to hospital records, we used other sources for data collection on births not included in the delivery and neonatal records, for death and stillbirth registrations and for validation.</p> <p>Results</p> <p>The average family size decreased mainly due to a decline in the proportion of families with 3 or more children. The distribution of mean maternal ages in all and in primiparous women was lowest in the mid 1970s, corresponding to a peak in the proportion of teenage mothers. The proportion of older mothers declined until the late 1970s (from 16.5% to 3.4%) followed by a steady increase. Mean birthweight in all and term babies gradually increased from the mid 1970s. The increase in the percentage of preterm birth paralleled a two-fold increase in the percentage of caesarean section among preterm births during the last two decades. The gap between the most affluent and the most deprived groups of the population widened over the three decades.</p> <p>Conclusion</p> <p>Key maternal and fetal factors affecting birth outcomes, such as maternal age, parity, socioeconomic status, birthweight and gestational age, changed substantially during the 32-year period, from 1961 to 1992. The availability of accurate gestational age is extremely important for correct interpretation of trends in birthweight.</p