Rapid and reliable assaying of Tc-99 in sediment samples with novel MTPN polymeric resin

The paper describes a new method for the rapid determination of Technetium (Tc) in sediment samples using solid-phase extraction chromatography (SPEC) with a novel methyl triphenyl phosphoniumnitrate (MTPN) resin. The effectiveness of the resin in selectively recovering Tc was evaluated in both batch and column mode and exploited for rapid analysis of 'Tc'. The procedure involves the acid digestion of samples, pre-concentration of fission products in supernatant and co-precipitation of actinides with Fe(OH)3, followed by selective recovery of Tc by SPEC using a column filled with MTPN resin. The recovered Tc was then radiometrically assayed using beta counting. The method was validated using IAEA certified reference materials and was found to provide reliable and reproducible results for the activity concentration of Tc-99 in sediment samples within 24 h.

Evaluation of BenzoDODA grafted polymeric resin for rapid and reliable assaying of plutonium in sediment samples

The paper reports a new rapid radioanalytical procedure for the determination of plutonium (Pu) in sediments by solid phase extraction chromatography (SPEC) using Bis-(2-ethylhexyl) carbamoyl methoxy phenoxy-bis-(2-ethylhexyl) grafted resin, abbreviated as Benzodioxodiamide (BenzoDODA) grafted resin. The resin was synthesized and evaluated for its sorption behaviour towards Pu in batch and column mode to determine its efficacy for selective recovery of Pu from sediment samples. The analytical procedure was based on the radiochemical separation of samples by acid digestion, followed by preconcentration of actinides by co-precipitation with Fe(OH)₃ and finally selective recovery of Pu by SPEC using a column filled with BenzoDODA grafted resin. Pu was then radiometrically assayed by preparing alpha disc sources with electro-deposition followed by alpha spectrometry. The method was further validated with IAEA reference materials. This method gives reliable and reproducible results for the activity concentration of Pu in sediment samples within 24 h.

Probing and understanding interaction of Eu(III) with γ- alumina in presenceof malonic acid

Radionuclide migration in aquatic environment is influenced by its sorption onto colloids/mineral oxides and the presence of organic complexing anions. With a view to understand the sorption of trivalent actinides by mineral oxides in presence of organic acid, in the present study, Eu(III), malonic acid (MA) and γ-alumina are considered as representatives of trivalent actinides, low molecular weight natural occurring organic acid and aluminol sites, respectively. The influence of MA on sorption of Eu(III) by γ-alumina was elucidated by batch sorption, spectroscopic techniques and surface complexation modeling, for the first time. Attenuated Total Reflection-Fourier Transform Infrared spectroscopic studies of MA sorbed on γ-alumina revealed the presence of two inner-sphere surface complexes. Batch sorption for binary (alumina-Eu(III)) and ternary (alumina-Eu(III)-MA) systems were investigated as a function of pH, Eu(III) concentration and sequential addition of Eu(III)/MA. The pH edge for Eu(III) sorption shifts to higher pH with increasing Eu(III) concentration. In ternary systems, Eu(III) sorption is significantly enhanced at pH < 4.5. Eu(III) speciation on γ-alumina is independent of addition sequence of Eu(III)/MA. Time resolved fluorescence spectroscopy of Eu(III) sorbed on γ-alumina exhibited two surface species, XOEu²⁺ and (YO)₂Eu⁺. The enhancement in I₆₁₆/I₅₉₂ and lifetime for ternary systems, as compared to binary system, at low pH, indicates the participation of Eu-MA complexes in the formation of surface species in ternary systems. The diffuse layer model has been employed to successfully model the experimental sorption profiles of binary and ternary systems, using code FITEQL 4.0, by considering the surface species identified by spectroscopic techniques.

Delineating the influence of picolinic acid on Eu(iii) sorption by γ-alumina

The present study aims at understanding the sorption mechanism of Eu(iii) by γ-alumina in the presence of picolinic acid (PA), a decontaminating agent used in the nuclear industry, through batch sorption studies, spectroscopy and surface complexation modeling. PA is weakly sorbed by γ-alumina, with the sorption increasing with pH up to 4.5 and decreasing with further increase in pH. Attenuated Total Reflection-Fourier Transform Infrared Spectroscopy (ATR-FTIR) measurements indicate that PA forms an inner sphere surface complex on γ-alumina. The presence of PA does not affect Eu(iii) sorption by γ-alumina at low [Eu(iii)], while it drastically reduces Eu(iii) sorption at high [Eu(iii)]. Similar Eu(iii) sorption profiles with different addition sequences of Eu(iii) and PA suggest identical Eu(iii) surface species for Eu(iii) sorption on γ-alumina in the presence of PA which has been validated by time resolved fluorescence spectroscopy (TRFS). TRFS measurements of Eu(iii) sorbed on γ-alumina in the absence (binary systems) and presence of PA (ternary systems) exhibited two components 1 & 2. The lifetime value of component 1 in ternary systems is enhanced compared to that in binary systems signifying the formation of new surface species containing Eu(iii), PA and the γ-alumina surface whereas the similarity of component 2 in both the binary and ternary systems reveals an almost identical coordination environment of Eu(iii) in the two types of system. Using the spectroscopic information obtained from TRFS, Eu(iii) sorption, at high [Eu(iii)], in ternary systems has been successfully modeled by considering Eu(iii) bridged PA surface species at both low and high affinity sites of γ-alumina. At low [Eu(iii)] both PA and Eu(iii) bridged ternary surface complexes only at high affinity sites of γ-alumina could describe the Eu(iii) sorption adequately.

Genetics and Expression Analysis of Anthocyanin Accumulation in Curd Portion of Sicilian Purple to Facilitate Biofortification of Indian Cauliflower

The present study was undertaken to know the genetics of purple color of cauliflower curds using a Sicilian purple 'PC-1' and a white curding mid-late group genotype of Indian cauliflower. For this, a cross was attempted between 'DC-466' (white curd) and 'PC-1' (purple curd) and observed intermediate level of purple pigmentation on curds in F₁ plants. Segregation of F₂ population (173) revealed that the purple color of the curd was governed by a single gene dominant over white, but the expression of trait was incomplete. It was substantiated by segregation of plants of BC₁ and F_{2:3(intermediate)} generations into 1(white):1(intermediate) and 1(white):2(intermediate):1(intense), respectively. The F₂, B₁, and B₂ generations segregated into purple(intermediate to intense): white curding plants in the ratio of 126: 47, 26:24, and 40:0, respectively fitting well with the Mendelian ratio of single gene for purple curds. However, purple pigmentation on curds ranged from very light to intense, which corroborated with the wide range of anthocyanin content in F₂ (3.81-48.21 mg/100 g fw). Out of three molecular markers from high resolution map of Pr gene in purple color cauliflower 'Graffiti', only BoMYB3 marker could distinguish purple and white curding parents but did not show co-segregation while investigated in F₂ population. Expression of BoMYB1 gene was up regulated in both the purple curd genotypes 'PC-1' and 'Graffiti' in comparison to white curded 'DC-466', while BoMYB2 gene was slightly upregulated in 'PC-1' but down regulated in 'Graffiti'. Occurrence of 'broccoli type' F₂ individuals and their genetic stability in F_2:3 support the intermediate position of 'Sicilian purple' between broccoli (Calabrese) and cauliflower. There was not any correlation between curd coloration and pigmentation on apical leaf and stem portion, indicating difference of expression in 'PC-1' than 'Graffiti'. The information obtained is useful for breeding anthocyanin rich attractive purple curding 'specialty cauliflower' for better consumer health and growers' earnings.

Complexation of U(VI) with Cucurbit[5]uril: Thermodynamic and Structural investigation in aqueous medium

The assessment of cucurbituril (CBn) for selective removal of actinides from nuclear waste streams requires comprehensive understanding of binding parameters and coordination of these complexes. The present work is the first experimental report on complexation of actinide ion with Cucurbit[5]uril (CB5) in solution. The thermodynamic parameters (ΔG, ΔH and ΔS) for complexation of CB5 with U(VI) in formic acid water medium were determined using microcalorimetry and UV-Vis spectroscopy. The enthalpy and entropy of complexation revealed the partial binding of U(VI) to CB5 portal. The partial binding was confirmed by spectroscopic techniques viz. extended X absorption fine structure spectroscopy (EXAFS), ¹H and ¹³C NMR. The EXAFS χ(r) versus r spectra for U-CB5 complex has been fitted from 1.4 to 3.5 Å with two oxygen shells and a carbon shell. The presence of three carbon atom in secondary shell shows the involvement of only three carbonyl oxygens directly bonding to U(VI) which is in contrast to that calculated from gas phase DFT calculation of unhydrated system. The combined effect of hydration and formic acid encapsulation led to the enhanced stability of partially bound U(VI) to CB5. In the present work the binding of formic acid has also been studied by fluorescence spectroscopy. ESI-MS data shows the unusual stabilization of U(VI) by CB5 in gas phase.

Structural, luminescence, thermodynamic and theoretical studies on mononuclear complexes of Eu(III) with pyridine monocarboxylate-N-oxides in aqueous solution

The mononuclear complexes formed by Eu(III) with three isomeric pyridine monocarboxylate-N-oxides namely picolinic acid-N-oxide (PANO), nicotinic acid-N-oxide (NANO) and isonicotinic acid-N-oxide (IANO) in aqueous solutions were studied by potentiometry, luminescence spectroscopy and isothermal titration calorimetry (ITC) to determine the speciation, coordination, luminescence properties and thermodynamic parameters of the complexes formed during the course of the reaction. More stable six membered chelate complexes with stoichiometry (ML_i, i=1-4) are formed by Eu(III) with PANO while non chelating ML and ML₂ complexes are formed by NANO and IANO. The stability of Eu(III) complexes follow the order PANO>IANO>NANO. The ITC studies inferred an endothermic and innersphere complex formation of Eu(III)-PANO and Eu(III)-IANO whereas an exothermic and outer-sphere complex formation for Eu(III)-NANO. The luminescence life time data further supported the ITC results. Density functional theoretical calculations were carried out to optimize geometries of the complexes and to estimate the energies, structural parameters (bond distances, bond angles) and charges on individual atoms of the same. Theoretical approximations are found to be in good agreement with the experimental observations.

Stability, speciation and spectral properties of NpO2+ complexes with pyridine monocarboxylates in aqueous solution

Neptunyl ion as NpO₂⁺ is the least reacting and most mobile radioactive species among all the actinides. The picolinic acid used for decontamination is co-disposed along with the radioactive waste. Thus, in long term storage of HLW, there is high possibility of interaction of actinides and long lived fission products with the picolinate and can cause migration. The complexation of NpO₂⁺ with the three structural isomers of pyridine monocarboxylates provides an insight to explore the role of hetero atom (nitrogen) with respect to key binding moiety (carboxylate). In the present study, the log β values, speciation and spectral properties of NpO₂⁺ complexes with pyridine monocarboxylates viz. picolinate, nicotinate and isonicotinate, have been studied at 298K in 0.1M NaClO₄ medium using spectrophotometry. The complexation reactions involving protonated ligands are always accompanied by protonation/deprotonation process; thus, the protonation constants of all the three pyridine monocarboxylates under same conditions were also determined by potentiometry. The spectrophotometric data analysis for complexation of NpO₂⁺ with pyridine monocarboxylates indicated the presence of ML and ML₂ complexes with log β values of 2.96±0.04, 5.67±0.08 for picolinate, 1.34±0.09, 1.65±0.12 for nicotinate and 1.52±0.04, 2.39±0.06 for isonicotinate. The higher values of log β for picolinate were attributed to chelation while in other two isomers, the binding is through carboxylate group only. Density Functional Theory (DFT) calculations were carried out to get optimized geometries and electrostatic charges on various atoms of the complexes and free pyridine monocarboxylates to support the experimental data. The higher stability of NpO₂⁺ nicotinate and isonicotinate complexes compared to simple carboxylates and the difference in log β between the two is due to the charge polarization from unbound nitrogen to the bound carboxylate oxygen atoms.

Diffusion of Na(I), Cs(I), Sr(II) and Eu(III) in smectite rich natural clay

Diffusion of Na(I), Cs(I), Sr(II) and Eu(III) in smectite rich natural clay, proposed as a backfill material in the Indian geological repository, was studied using the out-diffusion method. Radiotracers (22)Na, (137)Cs, (85)Sr and (154)Eu were used; the first three are carrier-free enabling experimental work at sub-micromolar metal ion concentration, and Eu(III) tracer (154)Eu was used at sub millimolar concentration. An out-diffusion methodology, wherein a thin planar source of radioactivity placed between two clay columns diffuses out, was used to obtain the apparent diffusion coefficient (Da) values. This methodology enabled determination of diffusion coefficient even for strongly sorbing (154)Eu. Da values for (22)Na, (137)Cs, (85)Sr and (154)Eu were 2.35 (±0.14) × 10(-11), 2.65 (±0.09) × 10(-12), 3.32 (±0.15) × 10(-11) and 1.23 (±0.15) × 10(-13) m(2) s(-1), respectively. Da values were found to be in fair agreement with literature data reported for similar mineralogical sediments. Sorption of radionuclides on the clay was also determined in the present study and differences in Da values were rationalized on the basis of sorption data. Distribution ratios (Kd) for Cs(I) and Eu(III) were higher than that for Sr(II), which in turn was higher than that for Na(I).

Performance demonstration of 4πβ(LS)-γ coincidence counting system for standardization of radionuclides with complex decay scheme

A standardization of (134)Cs and (131)I was carried out in order to demonstrate the performance and applicability of the 4πβ(LS)-γ coincidence counting system for standardization of radionuclides with complex decay scheme. The coincidence analyzer, capable of analyzing coincidence between beta and two gamma windows simultaneously, was developed and used for the standardization. The use of this dual coincidence analyzer has reduced the total experimental time by half. The activity concentrations obtained using the 4πβ(LS)-γ coincidence counting system, a 4πβ(PC)-γ coincidence counting system, and the CIEMAT/NIST method are in excellent agreement with each other within uncertainty limits and hence demonstrates its performance for standardization of radionuclides decaying with complex decay scheme. Hence use of this 4πβ(LS)-γ coincidence counting system can be an alternative method suitable to standardize radionuclides with complex decay scheme with acceptable precision.

Development of liquid scintillation based 4πβ(LS)-γ coincidence counting system and demonstration of its performance by standardization of ⁶⁰Co

A single-vial, single-PMT 4πβ(LS)-γ coincidence counting system has been developed at the Radiation Safety Systems Division, BARC. It has advantages of simple sample preparation, higher counting efficiency and the absence of self absorption over the conventional proportional counter based 4πβ(PC)-γ coincidence counting system. The performance of the system is demonstrated by standardizing a (60)Co solution using the 4πβ(LS)-γ coincidence counting system, 4πβ(PC)-γ coincidence counting system and CIEMAT/NIST method and comparing the results obtained by each method. The detection efficiency of liquid scintillation counter of the 4πβ(LS)-γ coincidence counting system was varied by color quenching, by chemical quenching and by varying the bias voltage applied to the LSC PMT. For the proportional counter based 4πβ(PC)-γ coincidence counting system the detection efficiency was varied by source self absorption. The activity concentrations obtained using the 4πβ(LS)-γ coincidence counting system, the 4πβ(PC)-γ coincidence counting system and the CIEMAT/NIST method are comparable within the uncertainty limits.

Facilitated transport of Pd(II) through a supported liquid membrane (SLM) containing N,N,N',N'-tetra-(2-ethylhexyl) thiodiglycolamide T(2EH)TDGA: a novel carrier

A novel carrier, N,N,N',N'-tetra-(2-ethylhexyl) thiodiglycolamide, T(2EH)TDGA has been studied for transport of Pd(II) from nitric acid medium across a supported liquid membrane (SLM). Pd(II) was found to be almost quantitatively transported (≈ 99.9%) within 2h from 3.0M HNO(3) medium using 0.05 M T(2EH)TDGA in n-dodecane as carrier and 0.01 M thiourea in 0.2M HNO(3) as strippant. Pd(II) transport was also studied against various parameters like feed acidity, carrier concentration, membrane pore size, etc. Palladium transport was found to be diffusion controlled and the diffusion co-efficient value was found to be 3.56 × 10(-5)cm(2)/s. Selectivity of T(2EH)TDGA for palladium over other fission products was found to be quite high, with the separation factors for Pd, with respect to different fission products being >10(3). With respect to leaching out of carrier from the membrane support, the membrane was found to be stable for six consecutive cycles. Thus, T(2EH)TDGA can be used as an efficient carrier of Pd(II) from nitric acid medium.

Effect of humic acid on sorption of technetium by alumina

Sorption of technetium by alumina has been studied in absence as well as in presence of humic acid using (95)Tc(m) as a tracer. Measurements were carried out at fixed ionic strength (0.1M NaClO(4)) under varying pH (3-10) as well as redox (aerobic and reducing anaerobic) conditions. Under aerobic conditions, negligible sorption of technetium was observed onto alumina both in absence and in presence of humic acid. However, under reducing conditions (simulated with [Sn(II)] = 10(-6)M), presence of humic acid enhanced the sorption of technetium in the low pH region significantly and decreased at higher pH with respect to that in absence of humic acid. Linear additive as well as surface complexation modeling of Tc(IV) sorption in presence of humic acid indicated the predominant role of sorbed humic acid in deciding technetium sorption onto alumina.

Sorption of curium by silica colloids: effect of humic acid

Sorption of curium by silica colloids has been studied as a function of pH and ionic strength using (244)Cm as a tracer. The sorption was found to increase with increasing pH and reach a saturation value of ∼95% at pH beyond 5.3. The effect of humic acid on the sorption of (244)Cm onto silica was studied by changing the order of addition of the metal ion and humic acid. In general, in the presence of humic acid (2 mg/L), the sorption increased at lower pH (<5) while it decreased in the pH range 6.5-8 and above pH 8, the sorption was found to increase again. As curium forms strong complex with humic acid, its presence results in the enhancement of curium sorption at lower pH. At higher pH the humic acid present in the solution competes with the surface sites for curium thus decreasing the sorption. The decrease in the Cm sorption in presence of humic acid was found to be less when humic acid was added after the addition of curium. Linear additive model qualitatively reproduced the profile of the Cm(III) sorption by silica in presence of humic acid at least in the lower pH region, however it failed to yield quantitative agreement with the experimental results. The results of the present study evidenced the incorporation of Cm into the silica matrix.

Sorption of 137Cs, 133Ba and 154Eu by synthesized sodium aluminosilicate (Na-AS)

Sodium aluminosilicate has been synthesized by solution route for use as a sorbent for various radionuclides. It was characterized by XRD, zeta potential, BET surface area, FTIR spectroscopy and site density measurement. Sorption studies of (137)Cs, (133)Ba and (154)Eu on synthesized sodium aluminosilicate have been carried out at varying pH (3-10). Sorption of all the metal ions was found to increase with pH of suspension with the saturation value increasing with the oxidation state of metal ion. Effect of Aldrich humic acid (2mg/l) on sorption was also investigated. In case of (137)Cs, the sorption was not affected by the presence of humic acid, while in case of (133)Ba and (154)Eu, sorption was enhanced at lower pH and decreased at higher pH in presence of HA. A series of experiments were carried out for (154)Eu sorption on sodium aluminosilicate at various conditions. Sorption of europium was analyzed by different sorption isotherms, viz., Freundlich and D-R isotherm. Thermodynamic data reveal sorption phenomena as endothermic and spontaneous. Studies were further extended to find out effect of diverse ions (Ca(2+) and CO(3)(2-)) on sorption of europium.

Spectroscopic investigation on europium complexation with humic acid and its model compounds

Time resolved fluorescence spectroscopy (TRFS) of Eu(III) (an analogue of trivalent actinides) complexation with humic acid (HA) and its model compounds, namely phthalic acid (PA), mandelic acid (MA) and succinic acid (SA) has been carried out at varying concentration ratios of ligand to metal ion. The emission spectra were recorded in the range of 550-650nm by exciting at an appropriate wavelength. The intensity of the 616nm peak of Eu(III) was found to be sensitive to complexation. The ratio of the intensities of 616 and 592nm peaks was used to determine the stability constants of Eu-phthalate, Eu-mandelate and Eu-succinate complexes. In the case of model compounds, the life-time was found to increase with increasing ligand to metal ratio (L/M) indicating the decrease in quenching of the fluorescence by coordinated water molecules with increasing complexation. On the other hand in the case of HA, the life-time was found to be constant at least up to L/M of 5, indicating the formation of outer sphere complex. Beyond L/M=5 the life-time value was found to increase which can be attributed to the binding of the metal ion to the higher affinity sites in the HA macromolecule.

Role of magnetite and humic acid in radionuclide migration in the environment

Sorption of (137)Cs, (90)Sr, (154)Eu and (141)Ce by magnetite has been studied at varying pH (4 to 11) in the presence and absence of humic acid. The sorption studies have also been carried out at varying ionic strength (0.01 to 0.2 M NaClO(4)) and humic acid concentration (2 to 20 mg/L). Percentage sorption of (137)Cs and (90)Sr was found to be pH dependent, with the sorption increasing with increasing pH of the suspension. At any pH, the percentage sorption of (90)Sr was higher than that of (137)Cs. The results have been explained in terms of the electrostatic interaction between the positively charged metal ions and the surface charge of the magnetite which becomes increasingly negative with increasing pH. On the other hand, (154)Eu and (141)Ce were found to be strongly sorbed by the magnetite at all pH values, with the sorption being independent of pH. The strong sorption of trivalent and tetravalent metal ions suggests the role of complexation reactions during sorption, apart from the electrostatic interactions. However, in the case of (141)Ce surface precipitation of Ce(III) formed by reduction of Ce(IV) in the presence of magnetite cannot be ruled out. Presence of humic acid (2 mg/L) was found to have negligible effect on sorption of all metal ions.

Ionic transport behavior of BaO containing sodium borosilicate glasses

The present manuscript describes the preparation, characterization and electrical behavior of sodium borosilicate glasses with varying concentrations of BaO, while maintaining the SiO(2):B(2)O(3):Na(2)O ratios constant for all the samples. The effect of BaO substitution on the ionic conductivity of glasses was studied by ac impedance analyzer, below the glass transition temperature. The diffusion coefficient (D) of each sample has been determined from the values of electrical conductivity and density. The activation energy for sodium ion transport has been calculated from the values of diffusion coefficients at different temperatures. The electrical properties of the modified glass have been explained on the basis of the structural factor.

Time resolved fluorescence spectroscopy of Eu(III) complexation with alpha-hydroxy isobutyric acid

Complexation of Eu(III) with alpha-hydroxy isobutyric acid (HIBA), a model compound of humic acid, has been studied by time resolved fluorescence spectroscopy. The ratio of fluorescence intensity of the two peaks at 616 and 592 nm (I(616/592)) was found to increase with increasing ligand to metal ratio. The I(616/592) data was used to deduce the stability constant of Eu-HIBA complexes of the type ML(i) (i=1-3). The formation of multiple ligand complexes was also corroborated by lifetime data which was found to increase with increasing [HIBA]/[Eu] ratio thus indicating replacement of coordinated water molecules by HIBA.

Effect of barium on diffusion of sodium in borosilicate glass

Diffusion coefficients of sodium in barium borosilicate glasses having varying concentration of barium were determined by heterogeneous isotopic exchange method using (24)Na as the radiotracer for sodium. The measurements were carried out at various temperatures (748-798 K) to obtain the activation energy (E(a)) of diffusion. The E(a) values were found to increase with increasing barium content of the glass, indicating that introduction of barium in the borosilicate glass hinders the diffusion of alkali metal ions from the glass matrix. The results have been explained in terms of the electrostatic and structural factors, with the increasing barium concentration resulting in population of low energy sites by Na(+) ions and, plausibly, formation of more tight glass network. The leach rate measurements on the glass samples show similar trend.

Intestinal infections

Gastrointestinal infections are the significant cause of childhood morbidity and mortality worldwide. Gastrointestinal infections reflects the balance between the intrinsic virulence factors of the enteropathogens and host mechanisms which defend against enteric infections. Host defense factors include gastric acidity, intestinal motility, the normal indigenous intestinal microflora, mucous secretion, and specific mucosal and systemic immune mechanisms. Majority of GI infections are self limited so on one hand antibiotics are not needed and on the other hand the irrational use of antibiotics produces resistant strains. Acute diarrheal diseases which are one of the important intestinal infections, in majority of the cases are viral and have short course. Antibiotics are recommended only in specific cases and in immunocompromised individuals. Gastrointestinal disease is one of the most common manifestations of HIV infection. The gastrointestinal tract contains abundant quantities of lymphoid tissue and is likely to function as a reservoir of HIV infection, a site of profound immune dysregulation, and a target for opportunistic infections. In this situation specific antibiotics are indicated.

Hepatobiliary abnormalities and parenteral nutrition

Hepatobiliary dysfunctions (TPN-HBD) occur during parenteral nutrition. In older children these are usually reversible whereas in newborns and infants these hepatobiliary abnormalities play a significant role in the morbidity. Cholestasis is a commonly occurring TPN-HBD. It correlates directly with the decreasing gestational age, low birth weight and increasing duration of TPN therapy. The pathogenesis of cholestasis of TPN is multifactorial and predisposed by necrotising enterocolitis, sepsis, cardiac failure, shock, and hypotension. Diagnosis is made with exclusion of other causes of direct hyperbilirubinemia. Most TPN-HBD appear within 4 weeks of starting of TPN but severe complications manifest usually after the 16th week. Histologically there is intralobular cholestasis. In few cases there may be severe portal fibrosis followed by development of micronodular biliary cirrhosis. Enteral starvation, defective bile acid carriers, hypercaloric TPN are the major factors responsible for TPN-HBD, including cholestasis. Biliary complications of TPN-HBD are acalculous, cholecystitis, and cholelithiasis. Bile stasis is a major pathological factor for these. If the calories are provided only by glucose or glucose-containing electrolyte solutions it may lead to cholestasis and other TPN-HBD. Even small oral alimentation (continuous or bolus) during TPN, prevent TPN-HBD. Choleretic agents have been useful in the prevention and management of cholestasis and other parenteral nutrition induced hepatobiliary abnormalities.

Infantile cholestasis--advances in its understanding: new concepts

Cholestasis is decrease or absence of bile flow into the duodenum. It can be either or in combination pathology of hepatocytes, intrahepatic bile ducts or extrahepatic bile ducts. Hepatocyte with their bile secretory apparatus and tight junction between hepatocytes are of specific importance in this. Bile is formed by several different energy-dependent transport processes. Secretion of bile is a complex metabolic process, which depends upon multiple structural and functional components in the hepatocytes and bile duct cells. The regulation of bile flow is regulated by many hormones. Bile is secreted in bile ducts having pressure of 15-25 cm of water. Rise in pressure in these bile ducts of more than 35 cm of water result suppression of bile flow and jaundice. A rise of conjugated serum bilirubin above the value of 400-500 mumol/L finds an alternate excretory pathway like urine. Various conditions are responsible for infantile cholestasis and can have different outcome of chronic cholestasis. These can be extrahepatic or intrahepatic and acute or chronic. Pathological consequences of infantile cholestasis are mainly because of malabsorption of fat and fat-soluble vitamins and hepatocellular dysfunctions. A battery of tests are required to diagnose the early infantile cholestasis. In the management of cholestasis diet rich in MCT is needed. Further, a high caloric intake up to 200 kcal/day to get adequate weight gain is desirable. Phototherapy, phenobarbitone and rifampicin is helpful in the pruritus of cholestasis by enhancing the excretion of bile. Ursodeoxycholic acid is specifically helpful in the cholestasis. A number of anti-inflammatory and immunosuppressive agents and a new compound, FK 506 has specific role in the management.

Hepatitis E in India

Institute of Pediatric Gastroenterology is superspecialised referral institute for all Pediatric Gastroenterological diseases from all over the country and for adjoining countries. We have our data and experience on 10,500 cases of proven Hepatitis E (HEV) in Pediatric population. HEV is non-enveloped 27-30 nm diameter RNA virus, prototype for alpha-like supergroup of positive stranded RNA virus. Indian HEV strain has 97% nucleotide and 98% amino acid sequence identity with Chinese strains but much diversity with Mexican strain. More than 70% acute hepatitis occurring in Pediatric population in this subcontinent are caused by HEV and 80% of these are sporadic. 90% cases were enterically transmitted, spread primarily by fecally contaminated drinking water (70%) and by food (20%), in 9.5% case spread probably was because of person to person and household contact. We could demonstrate HEV in urine, respiratory secretions. Interestingly we found HEV in insects like Flies, Cockroaches, and also in engorged Bedbugs and in Mosquitoes, apart from briefly boiled Mussels, and partially cooked cockles. Maternal-neonatal transmission could be seen if mother had HEV infection in third trimester of pregnancy. In 5 cases we could demonstrate HEV in breast milk. By studying on 10 volunteers, 40% have anicteric form only accompanied by anorexia, epigastric pain. HEV appeared in serum before the icteric phase. Shedding of virus in stool starts before the icteric phase and continued during the high levels of abnormal ALT. Hepatitis IgG anti-HEV persist up to 4 years. In 5 cases we could establish Transfusion associated Hepatitis (TAH). No chronicity could be documented. 5% cases had fulminant viral Hepatitis (FVH)/Sub fulminant viral Hepatitis (SVH), alpha-interferon (IFN) has been proved beneficial in these cases, further use of intravenous PGEl could also be beneficial. Inadequate chlorination of drinking water was an important additional factor for causing epidemics. A free residual chlorine concentration of at least 0.5 mg/l for minimum of 30 minutes is considered adequate as quality of drinking water.