Outcome of ACHD patients with non-inducible versus inducible IART undergoing cavo-tricuspid isthmus ablation: the role of empiric ablation.

PURPOSE: Catheter ablation for supraventricular tachycardia (SVT) in adults with congenital heart disease (ACHD) is an important therapeutic option. Cavo-tricuspid isthmus (CTI)-dependent intraatrial re-entrant tachycardia (IART) is common. However, induction of sustained tachycardia at the time of ablation is not always possible. We hypothesised that performing an empiric CTI line in case of non-inducibility leads to good outcomes. Long-term outcomes of empiric versus entrained CTI ablation in ACHD patients were examined. METHODS: Retrospective, single-centre, case-control study over 7 years. Arrhythmia-free survival after empiric versus entrained CTI ablation was compared. RESULTS: Eighty-seven CTI ablations were performed in 85 ACHD patients between 2010 and 2017. The mean age of the cohort was 43 years and 48% were male. Underlying aetiology included ASD (31%), VSD (11.4%), AVSD (9.1%), AVR (4.8%), Fallot's (18.4%), Ebstein's (2.3%), Fontan's palliation (9.2%) and atrial switch (13.8%). CTI-dependent IART was entrained in 59 patients whereas it was non-inducible in 28. The latter had an empiric CTI ablation. Forty-three percent of procedures were performed under general anaesthesia. There were no reported procedural complications. There was no significant difference in the mean procedure or fluoroscopy times between the groups (empiric vs entrained CTI; 169.1 vs 183.3 and 28.1 vs 19.9 min). Arrhythmia-free survival was 64.3% versus 72.8% (p value 0.44) in the empiric and entrained groups at 21 months follow-up. CONCLUSIONS: Long-term outcomes after empiric and entrained CTI ablation for IART in ACHD patients are comparable. This is a safe and effective therapeutic option. In the case of non-inducibility of IART, an empiric CTI line should be considered in this cohort.

Characteristics of the positive ion source at reduced gas feed.

The neutral beam injector of steady state superconducting tokamak (SST1-NBI) at IPR is designed for injecting upto 1.7 MW of neutral beam (Hº, 30-55 keV) power to the tokamak plasma for heating and current drive. Operations of the positive ion source (PINI or Plug-In-Neutral-Injector) of SST1-NBI were carried out on the NBI test stand. The PINI was operated at reduced gas feed rate of 2-3 Torr l/s, without using the high speed cryo pumps. Experiments were conducted to achieve a stable beam extraction by optimizing operational parameters namely, the arc current (120-300 A), acceleration voltage (16-40 kV), and a suitable control sequence. The beam divergence, power density profiles, and species fractions (H(+):H2(+):H3(+)) were measured by using the diagnostics such as thermal calorimetry, infrared thermography, and Doppler shift spectroscopy. The maximum extracted beam current was about 18 A. A further increase of beam current was found to be limited by the amount of gas feed rate to the ion source.

The four-variable modification of diet in renal disease formula underestimates glomerular filtration rate in obese type 2 diabetic individuals with chronic kidney disease.

AIMS/HYPOTHESIS: GFR is commonly estimated using the four-variable Modification of Diet in Renal Disease (MDRD) formula and this forms the basis for classification of chronic kidney disease (CKD). We investigated the effect of obesity on the estimation of glomerular filtration rate in type 2 diabetic participants with CKD. METHODS: We enrolled 111 patients with type 2 diabetes mellitus in different stages of CKD. GFR was measured using (51)Cr-labelled EDTA plasma clearance and was estimated using the four-variable MDRD formula. RESULTS: The bias between estimated and measured GFR was -22.4 (-33.8 to -11.0) p < 0.001 in the obese group compared with -6.04 (-17.6 to -5.5) p = 0.299 in the non-obese group. When GFR was indexed to body surface area of 1.73 m(2), the bias remained significant at -9.4 (-13.4 to -5.4) p < 0.001 in the obese participants. CONCLUSIONS/INTERPRETATION: This study suggests that the four-variable MDRD formula significantly underestimates GFR in obese type 2 diabetic participants with CKD.

Rapidly deteriorating renal function with membranoproliferative glomerulonephritis Type 1 associated with hepatitis C treated successfully with steroids and antiviral therapy: a case report and review of literature.

INTRODUCTION: The hepatitis C virus (HCV) infection is associated with several renal diseases including mixed essential cryoglobulinemia, membranoproliferative glomerulonephritis (MPGN) and less frequently membranous nephropathy and crescentic glomerulonephritis. We present a case of HCV-associated cryoglobulin-negative, MPGN Type 1 with features of early crescents and rapidly deteriorating renal function requiring urgent treatment. CASE: A 35-year-old male was admitted with history of arthralgia and erythematous rash. His past medical history included being an intravenous drug abuser. Biochemistry test showed raised serum creatinine of 150 micromol/l. He had nephrotic range proteinuria of 6 g/day and a serum albumin of 23 g/l. Viral serology for hepatitis B and HIV was negative but confirmed evidence of HCV infection with genotype 3A and viral load of 151,014 copies. He had a renal biopsy and histology demonstrated features of crescentic MPGN Type 1. His renal function deteriorated rapidly with his serum creatinine rising to 300 micromol/l over 2 days. We commenced treatment with intravenous methylprednisolone, 500 mg once daily (o.d.) for 3 days, followed by oral prednisolone 40 mg o.d. Concurrently, pegylated Interferon- (IFN) I+/- was commenced. After a 2-week treatment, his renal function showed remarkable recovery with creatinine reduced to 140 micromol/l. After 3 months, ribavirin was added when his renal function remained stable. He had tolerated his treatment without any major side effects. At 6 months follow-up clinic, his renal function was normal with serum creatinine of 69 micromol/l, 24-h urinary protein had dropped to 0.35 g/day, serum albumin increased to 38 g/l and HCV PCR was negative. DISCUSSION: The current treatment strategy of HCV-associated renal diseases includes targeting viral trigger HCV with interferon and ribavirin. Both IFN-I+/- and ribavirin have their limitation and adverse effects. In a clinical scenario where there is evidence of rapidly deteriorating renal function with crescentic glomerulonephritis, cautious use of immunosuppressive therapy may well be essential in the acute stage to halt the progression of kidney damage. Literature review of the treatment strategy for MPGN Type 1, cryoglobulin-negative with early features of crescents associated with HCV showed that there was no report or guideline available. CONCLUSIONS: To our knowledge, this is the first case in the literature of rapidly progressing MPGN Type 1 associated with HCV and nephrotic syndrome treated successfully with antiviral drugs and steroids concurrently. Our case highlights an important treatment strategy and may be beneficial to nephrologists facing this clinical scenario in the future. However, a randomized controlled trial is required to evaluate the efficacy of this treatment combination before it can be a standard treatment.

Retroperitoneal Castleman's disease mimicking soft tissue tumour.

Castleman's disease is a type of non-neoplastic lymphoproliferative disease having lymph nodal hyperplasia. It has two distinct microscopic types: hyaline-vascular type and plasma cell type. Clinically, it may present either as a solitary mass, most commonly in the mediastinum, or as a multicentric form whose features are generalized lymph-adenopathy, splenomegaly and involvement of other organs like the lungs and kidneys. Here we report a case of isolated retroperitoneal Castleman's disease, which presented as a lump in the iliac fossa in a young female. A clinico-radio-logical diagnosis of retroperitoneal soft tissue tumour was made and the patient underwent complete surgical excision. The exact diagnosis was only obtained at histopathology and there is no evidence of recurrence at six months follow-up.

Polymerization site in the beta chain of fibrin: mapping of the B beta 1-55 sequence.

The formation of a fibrin clot occurs through binding of putative complementary sites, called fibrin polymerization sites, located in the NH2- and COOH-terminal domains of fibrin monomer molecules. In this study, we have investigated the structure of the NH2-terminal fibrin polymerization site by using fibrinogen-derived peptides and fragments. Fibrinogen was digested with Crotalus atrox protease III, to two major molecular species: a Mr 325,000 derivative (Fg325) and a peptide of Mr 5000. The peptide and its thrombin-cleavage product were purified by ion-exchange and reverse-phase HPLC; the authenticity of the B beta 1-42 and beta 15-42 peptides, respectively, was confirmed by amino acid sequencing. Since Fg325 had decreased thrombin coagulability, we addressed the question of whether the peptide B beta 1-42 contained a fibrin polymerization site. In order to identify and map the site, the peptides B beta 1-42 and beta 15-42 were tested for their ability to inhibit fibrin monomer polymerization. In addition the following peptides prepared by chemical synthesis were also tested: beta 15-18, beta 15-26, beta 24-42, beta 40-54, beta 50-55, and alpha 17-19-Pro. While B beta 1-42 had no inhibitory activity, the peptide devoid of fibrinopeptide B, beta 15-42, was a strong inhibitor. The peptides beta 15-18, beta 15-26, and beta 15-42 decreased the rate of fibrin polymerization by 50% at a molar excess of the peptide to fibrin monomer of 500, 430, and 50, respectively. The peptides beta 24-42, beta 40-54, and beta 50-55 were inactive.(ABSTRACT TRUNCATED AT 250 WORDS)

Iron loading anaemias.

Iron loading anaemias are characterized by anaemia, high serum iron, transferrin saturation and ferritin values, and haemosiderin deposits in parenchymal cells and reticuloendothelial tissue with or without organ dysfunction. Sideroblastic anaemias and congenital dyserythropoietic anaemias (CDA) are important types of iron loading anaemias. Two cases of sideroblastic anaemia and five cases of CDA type I are presented as prototypes of iron loading anaemias. Increased gastrointestinal absorption of iron remains the main mechanism of iron loading in these anaemias. Phlebotomy can be used to reduce the iron load in those with mild or moderate anaemia, whereas desferrioxamine can be used to chelate excessive iron in all cases irrespective of severity of anaemia.

Bone marrow iron in nutritional anaemias.

Bone marrow smears of 168 patients with nutritional anaemias attending the Dr. J.C. Patel, Department of Hematology, K.E.M. Hospital were stained by Prussian blue method for iron (haemosiderin). Iron in the bone marrow was classified as absent, decreased, normal or increased. Amongst 93 cases with transferrin saturation (TS) of less than 16% and normoblastic erythropoiesis, bone marrow iron was absent in 48 (51.6%) and decreased in 45 (48.4%). In 50 cases with TS of less than 16% and marrow showing megaloblasts and/or giant myelocytes and metamyelocytes, bone marrow iron was absent in 15 (30%), decreased in 22 (44%), normal in 7 (14%) and increased in 6 (12%). In 25 cases with TS over 16% and megaloblastic erythropoiesis, bone marrow iron was absent in 4 (16%), decreased in 1 (4%), normal in 7 (28%) and increased in 13 (52%). In 150 (89.3%) patients out of 168, bone marrow iron and TS gave concordant results whereas in 18 (10.7%), the results were discordant; former was encountered in cases of uncomplicated iron deficiency while latter was found with megaloblastic morphology of the marrow. It is concluded that there is a good correlation between TS and bone marrow iron and hence, either of the criteria can be used for the diagnosis of iron deficiency especially when it is not complicated by megaloblastosis.

Iron status of beta thalassemia carriers.

One hundred twenty-four relatives (aged 17-52 years) of 35 children with severe transfusion-dependent beta thalassemia major were investigated for their beta thalassemia carrier status (determined by Hb-A2 level) and iron status (determined by serum ferritin level). Forty-eight males had beta thalassemia trait (BTT) and 18 males did not have BTT (control); 41 females had BTT and 17 females did not have BTT (control). Serum ferritin levels (mean +/- SEM) of male BTT, male control, female BTT, and female control groups were 151.0 +/- 27.4, 59.6 +/- 16.3, 120.6 +/- 36.6, and 17.2 +/- 6.1 mcg/liter respectively; the differences between the two male and the two female groups were statistically significant (p = .05 and p less than .001). Iron deficiency (serum ferritin below 10.0 mcg/liter) was present in 6.3%, 38.9%, 24.4%, and 58.8% of male BTT, male control Female BTT, and female control groups, respectively; the differences between the two male and two female groups were statistically significant (p less than .01 and p less than .01). Serum ferritin was over 1,000 mcg/liter in four individuals with BTT (2 male and 2 female). Thus, the BTT group had better iron nutrition. This may suggest that the BTT group has an advantage in maintaining iron balance.

cDNA-derived amino acid sequence of the gamma subunit of GTPase from bovine rod outer segments.

The sequence of the 74 amino acids in the gamma subunit of GTPase from bovine rod outer segments has been deduced from the cDNA sequence. Enriched GTPase mRNA was used to prepare a cDNA library in the expression vector lambda gt11. Clones encoding the gamma subunit were identified by screening the library with anti-GTPase antibodies and by cell-free translation of hybrid-selected mRNA. The longest cDNA (448 base pairs) contained the amino acid coding region for the entire gamma subunit as well as 5' and 3' noncoding regions of 67 and 159 base pairs, respectively. The 3' noncoding region contained the sequence, A-A-U-A-A-A, the presumed recognition sequence for polyadenylylation, and a 14-unit long poly(A) tract. The amino acid sequence derived for the gamma-subunit is mostly in agreement with that previously determined by McConnell and co-workers [McConnell, D. G., Kohnken, R. E. & Smith, A. J. (1984) Fed. Proc. Fed. Am. Soc. Exp. Biol. 43, 1585] and the partial sequence deduced by Van Dop and co-workers from cDNA [Van Dop, C., Medynski, D., Sullivan, K., Wu, A. M., Fung, B. K.-K. & Bourne, H. R. (1984) Biochem. Biophys. Res. Commun. 124, 250-255].

Conservation of human fibrinogen conformation after cleavage of the B beta chain NH2 terminus.

Human fibrinogen exposed to protease III from Crotalus atrox venom is cleaved near the NH2 terminus of the B beta chain yielding a species of Mr 325,000 (Fg325) with impaired thrombin clottability. The derivative was compared with intact fibrinogen in a number of ways to determine whether the functional defect resulted from a conformational change or from the loss of a polymerization site. NH2-terminal amino acid sequencing of isolated A alpha, B beta, and gamma chains showed that Fg325 contained intact A alpha and gamma chains, but differed from fibrinogen by the absence of the first 42 residues of the B beta chain. Fibrinopeptide A was present and was cleaved at the same rate in both fibrinogen and Fg325. The rate and extent of A alpha and gamma cross-linking by factor XIIIa was also indistinguishable. In contrast, the thrombin-catalyzed coagulation of Fg325 was 46% less in extent and 180-fold slower than observed for intact fibrinogen. A conformational comparison of Fg325 and fibrinogen was made using immunochemical and spectroscopic approaches. Antisera specific for different regions of the fibrinogen molecule were used to characterize the epitopes in Fg325. The only significant differences were found in the NH2-terminal region of the B beta chain, probed with antiserum to B beta 1-118. The conformational similarity of Fg325 and fibrinogen was confirmed by the identity of both near and far UV CD spectra of the two proteins. Structural, functional, and immunochemical results imply that cleavage of 42 NH2-terminal residues from the B beta chain is not accompanied by a measurable conformational change. The residues of this B beta chain segment, which are evidently located on the surface of the molecule, in conjunction with the NH2-terminal part of the A alpha chain appear to play an important role in the expression of a fibrin polymerization site.

Anticoagulant proteases from western diamondback rattlesnake (Crotalus atrox) venom.

Crotalus atrox venom contains agents that render human fibrinogen and plasma incoagulable by thrombin. To elucidate the mechanism of alteration of fibrinogen clotting function by the venom, four immunochemically different proteases, I, II, III, and IV, were purified from the venom by anion-exchange chromatography and column gel filtration. All four proteases had anticoagulant activity rendering purified fibrinogen incoagulable. Proteases I and IV do not affect fibrinogen in plasma but in purified fibrinogen cleave the A alpha chain first and then the B beta and gamma chains. Both enzymes are metalloproteases containing a single polypeptide chain with 1 mol of zinc, are inhibited by (ethylenedinitrilo)tetraacetate and human alpha 2-macroglobulin, and have an optimal temperature of 37 degrees C and an optimal pH of 7. Protease I has a molecular weight (Mr) of 20 000 and is the most cationic. Protease IV has an Mr of 46 000 and is the most anionic glycoprotein with one free sulfhydryl group. Proteases II and III degrade both purified fibrinogen and fibrinogen in plasma, cleaving only the B beta chain and leaving the A alpha and gamma chains intact. Both enzymes are alkaline serine proteases, cleave chromogenic substrates at the COOH terminal of arginine or lysine, are inhibited by diisopropyl fluorophosphate and phenylmethanesulfonyl fluoride, and have an optimal temperature of 50-65 degrees C. Protease II is a single polypeptide chain glycoprotein with an Mr of 31 000. Protease III is a two polypeptide chain protein with an Mr of 24 000, each of the two chains having an Mr of 13 000; its activity is not affected by major protease inhibitors of human plasma. Proteases II and III are enzymes with unique and limited substrate specificity by cleaving only the B beta chain, releasing a peptide of Mr 5000 and generating a fibrinogen derivative of Mr 325 000, with intact A alpha and gamma chains and poor coagulability. Since the two enzymes are active in human plasma and serum, it is postulated that proteases II and III can mediate anticoagulant effects in vivo after envenomation.

Fibrinogenolytic afibrinogenemia after envenomation by western diamondback rattlesnake (Crotalus atrox).

The absence of fibrinogen and the presence of plasmic fragments X, Y, D, and E were demonstrated in a patient bitten by a western diamondback rattlesnake, Crotalus atrox. The factor VIII level and the platelet count were within normal limits. There were distinct changes of protease inhibitors in the patient's plasma. Alpha-1-protease inhibitor was elevated. Antithrombin-III was only slightly decreased after the envenomation, but alpha 2-antiplasmin and alpha 2-macroglobulin were initially significantly lowered, returning to normal values in 38 and 3 days, respectively. Plasmin-alpha 2-antiplasmin complex was present until day 10 after the envenomation. However, purified plasminogen was not activated in vitro by the venom. Cultured endothelial and smooth muscle cells from human blood vessels released an increased amount of plasminogen activator upon incubation with the venom. The release did not result from cell lysis. Platelets in normal human platelet-rich plasma were aggregated by 10 micrograms/ml of the venom, without serotonin secretion. The aggregation kinetics and serotonin secretion induced by adenosine diphosphate (ADP) or arachidonate were not significantly affected by the venom at 1-10 micrograms/ml. It is concluded that the predominant mechanism of afibrinogenemia in the patient after Crotalus atrox bite resulted from primary fibrinogenolysis and not from a consumptive coagulopathy. The lytic state seemed to be induced through an indirect activation of plasminogen by vascular plasminogen activator, which was probably released from endothelial cells and smooth muscle cells by the snake venom.

Unique degradation of human fibrinogen by proteases from western diamondback rattlesnake (Crotalus atrox) venom.

Thrombin-coagulability of both human fibrinogen and plasma was rapidly lost upon incubation with western diamondback rattlesnake (Crotalus atrox) venom. The dose- and time-dependent effect was due to direct proteolytic degradation of fibrinogen (Mr 340,000) by venom enzymes. Using purified fibrinogen as the substrate it was demonstrated that the venom degraded the A alpha chain first and then the B beta chain. The degradation pattern of fibrinogen in plasma was different to that of purified fibrinogen, since only the B beta chain was cleaved. A fibrinogen derivative isolated from venom-treated plasma had impaired thrombin-coagulability, Mr 325,000 +/- 10,000, its A alpha and gamma chains appeared intact and only the B beta chain was degraded to a species of Mr 52,000 +/- 1,500. The venom contained three proteolytic enzyme fractions as revealed by gel filtration chromatography. All abolished coagulability of purified fibrinogen, however, only one enzyme fraction rendered plasma incoagulable. The proteolytic enzyme with anticoagulant activity against plasma degraded only the B beta chain of purified fibrinogen, generating a derivative of Mr 325,000, which was identical to that obtained upon incubation of the crude venom with plasma. The polypeptide chain structure of the derivative indicates that the intact B beta chain of fibrinogen plays an important role in the formation of fibrin clots.