Overall vertical transmission of hepatitis C, transmission net of clearance, and timing of transmission.

Background: It is widely accepted that the risk of HCV vertical transmission (VT) is 5-6% in mono-infected women, and that 25-40% of HCV infection clears spontaneously within 5 years. However, VT and clearance rates have not been estimated from the same datasets, and there is a lack of information on VT rates 'net' of clearance. Methods: We re-analysed data on 1749 children in 3 prospective cohorts to obtain coherent estimates of overall VT rate and VT rates 'net' of clearance at different ages. Clearance rates were used to impute the proportion of uninfected children who had been infected and then cleared before testing negative. The proportion of transmission early in utero, late in utero and at delivery was estimated from data on the proportion of RNA positives in samples tested within three days of birth, and differences between elective caesarean and non-elective caesarean deliveries. Findings: Overall VT rates were 7.2% (95% credible interval 5.6-8.9) in mothers who were HIV negative and 12.1% (8.6-16.8) in HIV-co-infected women. The corresponding rates net of clearance at 5 years were 2.4% (1.1-4.1) and 4.1% (1.7-7.3). We estimated that 24.8% (12.1-40.8) of infections occur early in utero, 66.0% (42.5-83.3) later in utero, and 9.3% (0.5-30.6) during delivery. Conclusion: Overall VT rates are about 24% higher than previously assumed, but the risk of infection persisting beyond age 5 years is about 38% lower. The results can inform design of trials of to prevent or treat pediatric HCV infection, and strategies to manage children exposed in utero.

MO190NORMATIVE DATA FOR GLOMERULAR FILTRATION RATE IN HEALTHY KIDNEY DONOR POPULATION

Background and Aims Glomerular filtration rate (GFR) is estimated traditionally from 24-hour urinary creatinine clearance. Creatinine is mainly filtered by glomerulus. The collection of 24-hour urinary sample is a difficult task with many patients fail to collect all the urine samples. As measuring GFR is cumbersome, expensive, and not easily available in all centers, various equations are developed for estimating GFR from creatinine like MDRD, CKD EPI creatinine. GFR obtained from serum creatinine shows wide variation as muscle mass and dietary protein intake are important determinants of serum creatinine concentration. Literature shows very few studies with GFR estimation with reference to age in Indian population. Hence, this study is planned to develop age specific nomogram for GFR in healthy kidney donor population as well as to study agreement between GFR obtained by 99m Tc DTPA three sample method and GFR estimated by 24-hour urinary creatinine. The aim of this stidy was to develop age-specific nomogram GFR in healthy kidney donor population and to study the agreement between the GFR measured by Technetium-99m diethylene triamine pentaacetic acid (99m Tc DTPA) and 24-hour urinary creatinine method. Method This study was conducted at Sir Ganga Ram hospital, New Delhi. All healthy individuals aged more than 20 years and less than 65 years, undergoing evaluation as prospective kidney donor at our hospital were the part of this study. GFR was measured by 99m Tc DTPA clearance using 3 sample method. GFR measured by DTPA method was used to develop nomogram. Creatinine Clearance was calculated from 24-hour urinary creatinine by formula U x V/P where, U is urinary creatinine level, P is plasma creatinine level and V is total volume of urine. Nomogram was developed with respect to these 3 Age groups; namely, 20 to 40 years, 40 to 50 years and 50 to 65 years Results Total 100 kidney donors were included in this study. Enrolled subjects were divided into 3 age groups; 20 to 40 years (n=28), 40 to 50 years (n=46) and 50 to 65 years (n=26). Majority of the donors were females (n=80). The agreement between GFR obtained by 99m Tc DTPA and 24-hour urinary creatinine clearance methods was 92.6 vs. 94 ml/min, 80.4 vs. 76 ml/min and 76.3 vs. 70 ml/min in respective age groups. Conclusion In the younger age group (20 to 40 years), there is better agreement in GFR measured by 99m Tc DTPA method and 24-hour urinary creatinine clearance methods.

Aldosterone-dependent and -independent regulation of Na+ and K+ excretion and ENaC in mouse kidneys

We investigated the regulation of Na+ and K+ excretion and the epithelial Na+ channel (ENaC) in mice lacking the gene for aldosterone synthase (AS) using clearance methods to assess excretion and electrophysiology and Western blot analysis to test for ENaC activity and processing. After 1 day of dietary Na+ restriction, AS−/− mice lost more Na+ in the urine than AS+/+ mice did. After 1 wk on this diet, both genotypes strongly reduced urinary Na+ excretion, but creatinine clearance decreased only in AS−/− mice. Only AS+/+ animals exhibited increased ENaC function, assessed as amiloride-sensitive whole cell currents in collecting ducts or cleavage of αENaC and γENaC in Western blots. To assess the role of aldosterone in the excretion of a K+ load, animals were fasted overnight and refed with high-K+ or low-K+ diets for 5 h. Both AS+/+ and AS−/− mice excreted a large amount of K+ during this period. In both phenotypes the excretion was benzamil sensitive, indicating increased K+ secretion coupled to ENaC-dependent Na+ reabsorption. However, the increase in plasma K+ under these conditions was much larger in AS−/− animals than in AS+/+ animals. In both groups, cleavage of αENaC and γENaC increased. However, Na+ current measured ex vivo in connecting tubules was enhanced only in AS+/+ mice. We conclude that in the absence of aldosterone, mice can conserve Na+ without ENaC activation but at the expense of diminished glomerular filtration rate. Excretion of a K+ load can be accomplished through aldosterone-independent upregulation of ENaC, but aldosterone is required to excrete the excess K+ without hyperkalemia.

A Brief Presentation of the Characteristics of Hemodialysis Membranes

The survival of CKD patients has known significant improvement with the appearance of extrarenal clearance methods. Being a domain in a rapid progression, the hemodialysis membranes have been, in time, one of the key modifying points. In this paper will make a short presentation of the features of hemodialysis membranes and will point out aspects which need future research.