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Background and Objectives Pathogen reduction technology using amustaline (S-303) was developed to reduce the risk of transfusion-transmitted infection and adverse effects of residual leucocytes. In this study, the viability of red blood cells (RBCs) prepared with a second-generation process and stored for 35 days was evaluated in two different blood centres. Materials and Methods In a single-blind, randomized, controlled, two-period crossover study (n = 42 healthy subjects), amustaline-treated (Test) or Control RBCs were prepared in random sequence and stored for 35 days. On day 35, an aliquot of 51Cr/99mTc radiolabeled RBCs was transfused. In a subgroup of 26 evaluable subjects, 24-h RBC post-transfusion recovery, mean life span, median life span (T50) and life span area under the curve (AUC) were analysed. Results The mean 24-h post-transfusion recovery of Test and Control RBCs was comparable (83·2 ± 5·2 and 84·9 ± 5·9%, respectively; P = 0·06) and consistent with the US Food and Drug Administration (FDA) criteria for acceptable RBC viability. There were differences in the T50 between Test and Control RBCs (33·5 and 39·7 days, respectively; P 0·05). Following infusion of Test RBCs, there were no clinically relevant abnormal laboratory values or adverse events. Conclusion RBCs prepared using amustaline pathogen reduction meet the FDA criteria for post-transfusion recovery and are metabolically and physiologically appropriate for transfusion following 35 days of storage.

Understanding blood volume changes in children with malaria is important for managing fluid status. Traditionally, blood/red cell volume measurements have used radioactive chromium isotopes. We applied an alternative approach, using non-radioactive chromium-53 labelling and mass spectrometry to investigate red cell volume (RCV) in Gabonese children with malaria. Nineteen children with malaria participated (10 severe, 9 moderately severe; ages 15 months to 7 years). Blood labelled with 53Cr-chromate exvivo was re-injected, then sampled 30 min later. Pre- and post-injection 53Cr content were measured by gas chromatography/electron ionisation mass spectrometry of the chromium-trifluoroacetylacetone (TFA) chelate, calibrated against 50Cr standards. Blood and red cell volumes were calculated from isotopic dilution in 15 of 19 children (in four, insufficient signal mitigated analysis). In this small pilot study, there were no significant differences between moderate and severe cases. Including all subjects, the mean RCV was reduced compared with predicted values (184 vs. 269 mL; p = 0.016) but blood volume, 71 ± 33 mL/kg (normalised for weight), was close to predicted, ∼77 mL/kg, commensurate with reduced haematocrit. Blood lactate concentration correlated negatively with RCV/weight (r = −0.56, p = 0.028), consistent with anaemia. In one case, sequential samples over 42 days gave an estimated rate of 53Cr disappearance of 1.4%/day (equivalent half-life: 70 days). 53Cr-labelling of red cells may be used to estimate blood and red cell volumes and can be used as an investigative tool in situations such as childhood diseases and resource-constrained settings. Although the red cell mass is depleted in malaria, the blood volume appears relatively well preserved. Copyright © 2009 John Wiley & Sons, Ltd.

The intravascular clearance of intravenously administered endotoxin prior to and after administration of immune serum has been compared in untreated rabbits and in rabbits pretreated with warfarin sodium for 4 and 66 days, respectively. Firstly, the present observations show that the phagocytic rate of endotoxin without immune serum is significantly higher in rabbits exposed to “short-term” warfarin pretreatment than in those exposed to “long-term” pretreatment and in untreated rabbits. The “long-term” warfarin treatment is supposed to depress the function of the reticuloendothelial system, particularly in the liver. Secondly, the phagocytic rate of endotoxin increases significantly following the administration of immune serum, which almost completely abolishes the difference between the phagocytic rates of the groups prior to administration. Administration of immune serum seems to decrease the uptake of endotoxin in some organs or provoke an immediate redistribution of the endotoxin between the organs. The warfarin pretreatment influences the relative weight of the liver, and the duration of the warfarin pretreatment seems to influence the organ localization of endotoxin.

Red cells from 6 convalescent hospital patients without evidence of porphyria and from 2 patients with erythropoietic porphyria (5 studies) were incubated with delta amino laevulinic acid (ALA) thereby increasing the intracellular porphyrin concentration. These cells were then labelled with 3H DFP or DF32P and re-injected, and their life-span compared to a control population of cells labelled with the alternate isotope. Increasing the cellular porphyrin concentration did not alter red cell life-span. Similarly, increasing the level of porphyrins in rabbit whole blood did not diminish their life-span, when measured with radiochromium. These data indicate that increased intracellular porphyrin concentration does not prejudice red cell life-span, and that the haemolytic anaemia in patients with erythropoietic porphyria is not due to the increased intracellular porphyrin concentration.

The sites of destruction of 51Cr tagged G-6-PD deficient red cells in normal and primaquine sensitive Sardinians after drug administration have been studied by means of surface monitoring and, in one case, by direct quantitation after surgery. In practically all cases a liver to spleen ratio of one could be recorded, with a constant splenic participation in the uptake of radioactivity. It was observed that, beside the major role played by the liver in the sequestration and disposal of severely damaged G-6-PD deficient red cells after administration of primaquine, also the spleen has a significant share in the disposal of damaged cells.

The phytohaemagglutinin (PHA)-induced cytotoxic action of human blood lymphocytes against homologous cells in tissue culture was compared with the effect of human thymus cells. For quantitation of cell damage, use was made of the release of isotope from Chang cells (human liver) labelled with 51Cr-chromate. Two young male patients with congenital heart defects served as donors. The Chang target cells were not damaged by thymic lymphoid cells added in high excess. In contrast, a small number of blood lymphocytes from the same donors tested simultaneously damaged the target cells. The thymic cells were poorly stimulated to DNA synthesis and into blastoid transformation by incubation with PHA for 3 days. PPD induced no response in the thymus cells. The blood lymphocytes reacted normally in all tests. Most thymocytes survived 24 hr inkubation while only about 25 per cent were alive after 72 hr. 70 per cent blood lymphocytes survived 72 hr incubation. It is assumed that a majority of the human thymic lymphocytes are immunologically non-competent cells in regard to cellular immune reactivity. These cells lack cytotoxicity as well as ability to proliferate in the presence of PHA or antigens.

To 11 patients with sickle cell anaemia pharmacological doses of androgens were given for periods varying between 3 and 16 weeks. To 3 of the patients two courses of treatment were given. During the treatment 10 of the patients showed an increase of the total red cell mass varying between 25 and 125% of the control value. One patient did not respond. The treatment had no discernible effect on the sickling tendency of the erythrocytes at different levels of oxygen tension and there was no consistent alteration of the red cell survival measured with radioactive chromium. Weight gain was seen in all patients and hirsutism was seen in most of the females. In spite of the marked increase in red cell mass there was no certain increase in the frequency of crisis among the female patients. Priapism occurred in all of the adult males responding to the therapy. The number of patients studied is, however, small and the observation time too short to allow any firm conclusion on the effect of androgen treatment on the frequency of vaso-occlusive crisis.

3 patients with myelosclerosis have subsequently developed paroxysmal nocturnal haemoglobinuria, with positive in-vitro lysis tests (acidified-serum lysis, cold-antibody lysis and sucrose lysis), characteristic of PNH. These cases provide further evidence of a relationship between PNH and myeloproliferative disorders; they support the proposition that PNH is an acquired defect of erythropoiesis due to an abnormal clone. In two of the patients PNH has been severe with marked intravascular haemolysis, so that in these cases the clinical course and management of the original disease have been influenced by the PNH. In the third patient the PNH defect has, so far, been essentially only a phenomenon of in-vitro tests and apparently without clinical effect.

Two sisters had a congenital hypochromic anaemia in spite of hyperferraemia with a fully saturated serum transferrin, and in spite of heavy iron deposits in the liver. Bone marrow iron was reduced. The anaemia was markedly increased during pregnancy, when each of the sisters needed 8 blood transfusions. Erythrokinetic studies were compatible with hypoplastic anaemia. The bone marrow, however, was hyper-cellular with an increased erythropoiesis. Our patients resembled the two patients described by Shahid & Diamond (1964). It is postulated that the cause of the disease is a congenital defect in the one-way transport mechanism for iron from transferrin and into the erythroid cell.

The erythrocyte sequestration in the spleen and liver was investigated in 25 cases of immunohaemolysis by surface counting after infusion of 51Cr-labelled autologous erythrocytes. The erythrocyte sequestration pattern was found to depend upon the treatment with prednisone given at the time of the investigation and furthermore upon the total haemolytic intensity. Increased sequestration of erythrocytes in the liver is always present in cases of severe hyperhaemolysis. After prednisone treatment, hypersequestration of erythrocytes in the spleen predominates. In the present study increased sequestration in the liver was even demonstrated in about 50 % of the cases in which incomplete non-complement-fixing antibodies were found. In the majority of cases prednisone therapy gave only short-lasting remission. Frequently, it is difficult to reduce the dose of prednisone because of increasing haemolytic intensity. Complete, long-lasting remission seems to follow splenectomy in cases characterized by a splenic sequestration pattern during periods without prednisone therapy, but if hepatic hypersequestration has been demonstrated the remissions are not complete. The need for steroids decreased after splenectomy in practically all cases. A combination of prednisone therapy and early splenectomy is advisable in most cases of immunohaemolysis.

A case of infectious mononucleosis with longstanding thrombocytopenia, not responsive to corticosteroid therapy, is presented. Rapid normalization of the platelet level was revealed by splenectomy. The patient is the fourth known case in which it has been necessary to perform splenectomy. A study made with 51Cr-labelled homologous platelets showed a very short half-life, along with a high spleen/liver ratio of the activity. These examinations have not previously been performed in this condition.

Platelet kinetics, volume of megakaryocytes per μl sternal bone marrow, and the volume of the spleen have been quantitated in 20 cases of untreated polycythaemia vera (PV). There was a very good relationship between platelet production rate and megakaryocyte volume/μl bone marrow. The results suggest that megakaryopoiesis in PV represents mainly an effective platelet production. The megakaryocyte volume/μl bone marrow was significantly related to the body platelet mass (p < 0.001), but its relationship to the peripheral platelet count was significant only at the 10 % level. This was due to altered platelet distribution caused by differences in spleen and blood volumes. There was a negative relationship between platelet half-life time (T 1/2) and spleen volume (0.10 > p > 0.05) suggesting that enlargement of the spleen as such influences platelet survival. A highly significant correlation between platelet production rate and spleen volume, as well as between body platelet mass and spleen volume was found. The influence of the spleen size on platelet kinetics in PV has been discussed.

45 patients with chronic non-specific obstructive lung disease had a whole body/venous haematocrit ratio of 0.86 ± 0.008 SEM. This is lower than the ratio found in normal adults. For greatest accuracy independent measurement of red cell and plasma volumes should be undertaken in this condition.

The relationship between the exchangeable splenic platelet pool, determined by recovery of infused 51Cr-labelled platelets, and the spleen size, determined by 99mTc scintigraphy, has been investigated in 22 cases of polycythaemia vera and 6 control subjects. The results have shown a highly significant negative correlation, indicating that with increasing splenomegaly a larger proportion of the body platelet mass is pooled in the spleen. A scintigraphic determination of the spleen size gives a rough estimation of the splenic platelet pool.

Platelet survival studies were performed in three groups of males: 10 healthy young students, 8 healthy middle-aged men and 8 haematologically normal subjects with mild to moderate cardiovascular diseases. Two mathematical functions were used in order to obtain platelet mean life span. (MLS) according to the principle of Mills (1946). The two functions were equivalent for the estimation of platelet MLS. In all groups studied, the range for platelet MLS was wide, but was most pronounced in the group of subjects with cardiovascular diseases. The mean platelet MLS for young students was higher than the mean for healthy middle-aged men, and the mean for the latter was higher than the mean platelet MLS in the group of subjects with cardiovascular diseases. The differences between these three groups were, however, not statistically significant. The means for platelet destruction rate and turnover were equal in the two groups of healthy volunteers studied. In the group of subjects with cardiovascular diseases the mean for platelet destruction rate and turnover exceeded the means for healthy volunteers but not significantly so.

A simple analytical model has been worked out for quantitative assessment of temporary shifts in erythrocyte survival curves after labelling with radioactive tracers. This model was applied to 51Cr and DF32P curves from rabbits exposed to experimental fever induced by either bacterial pyrogen, heated milk or external heating in a climatic chamber. Thereby a quantitative expression of the fever-induced erythrocyte destruction was obtained. In all three methods for elevating the body temperature experimentally the studies showed an increased loss of activity during the fever, either in terms of the slope of the curve segment concerned with fever compared to the pre-or post-febrile periods or in terms of the deviation of the observed curves from the expected, spontaneous course in the rabbit. The maximum loss occurred soon after the initiation of fever, and prolongation of the fever period did not cause a continued increase in the destruction of the labelled erythrocytes. A certain correlation was found between the initial action of heat and the magnitude of the erythrocyte destruction. After the cessation of a short-lasting period of fever the tracer curve again approached the expected spontaneous course, explained by an age-dependent variation in the heat susceptibility of the erythrocytes. By using the age-distribution function for rabbit erythrocytes, an explanation of the demonstrated differences in the simultaneous changes in radioactivity and haemoglobin or PCV is attempted. It is concluded that elevated body temperature shortens the mean survival time of the red cells. The average reduction of the red cell mass in the present study was about 15% and the maximum loss about 35%.

Eleven patients with essential hypertension were treated with hydrochlorothiazide/KCl for three months. A significant fall in total blood volume, exchangeable sodium and blood pressure could be demonstrated both after one to two weeks and after three months of treatment, while a fall in serum sodium and body weight was only significant after one to two weeks of treatment. Thus, hypovolemia may, perhaps, be the explanation for the antipressor effect of thiazide even after three months of treatment.

At ten examinations the renal clearances of inulin and 51Cr-EDTA have been determined before, during and after hyperglycemia induced in nine normal young men. The blood glucose concentration was kept moderately elevated for a period of 2 to 3 hours by a combined oral and i.v. administration of glucose. During the hyperglycemia the inulin and 51Cr-EDTA clearances showed a highly significant increase averaging 14 and 13%, respectively. The urinary sodium excretion rate was reduced during the hyperglycemia. Five subjects were examined during a water load. No significant change occurred in the glomerular filtration rate (GFR). A possible explanation of the effect on the GFR of a glucose load could be an interaction between the glucose and sodium transport in the kidney combined with a moderate increase in the plasma volume.

Erythrocyte pooling and sequestration in the spleen were studied in 73 patients with splenomegaly due to various haematological disorders using 51Cr-labelled autologous erythrocytes and surface counting. Arbitrary values for the accumulation of activity in spleens of different sizes were obtained by correcting measured splenic surface activities (correction factors have been experimentally estimated). Absolute values for the splenic content of 51Cr and 125I were obtained by comparative surface activity measurements over the enlarged spleen and a model of the spleen charged with a known amount of activity. In this way the splenic erythrocyte and plasma volume may be estimated. In cases of pronounced splenomegaly without complicating immunohaemolysis the splenic erythrocyte pool (splenic erythrocyte volume/total erythrocyte volume) increases with increasing splenic weight, apparently independently of the underlying haematological disorder, the splenic erythrocyte content varying only with body haematocrit. Hyperhaemolysis is a regular finding in enlarged spleens. The splenic erythrocyte sequestration rate increases with increasing splenic erythrocyte pool and is much higher in myeloproliferative than in lymphoproliferative disorders. The total plasma volume is expanded in splenomegalic patients, but the splenic plasma volume constitutes only a minor part of this increment. The anaemia of splenomegalic patients is a consequence of splenic erythrocyte concentration and hypersequestration combined with expansion of the plasma volume. Frequently the total erythropoietic capacity is reduced. Splenectomy is regularly followed by an increased venous haemoglobin concentration.

A method for in vivo determination of the splenic erythrocyte and plasma volume has been developed. Ultrasonic scanning of the splenic region permits not only determination of the shape and topography of the spleen, but also calculation of its volume with great accuracy, using simultaneous computer analysis. Splenic models of a volume as determined by ultrasonic scanning were made of water-filled balloons and shaped as accurate copies of the scanned spleens. After infusion of known quantities of 51Cr-labelled erythrocytes and 125I-labelled albumin, intravenously and into a model of the patient's spleen, it may be determined – by surface measurements over the spleen in situ and over the balloon model – how large a part of the total erythrocyte and plasma volume is localized in the spleen. By the use of 59Fe, the method also allows quantitative determination of the iron incorporation in a spleen with extramedullary erythropoiesis. The percentage which the erythrocyte pool in the spleen constitutes of the total erythrocyte volume increases with increasing spleen weight, apparently independently of the underlying haematological disease.

The measurement of red blood cell survival in the circulation has progressed from the original differential agglutination technique of Ashby to current isotopic and flow cytometric methods. While occasionally useful in the clinic, these methods find widespread use in a number of important research areas, including the evaluation of new red cell storage media in transfusion medicine and studies of the pathophysiology of sickle cell disease and diabetes. In this review, measurement techniques are placed in historical perspective and examined for relative merits and suitable application. Am. J. Hematol., 2009. © 2008 Wiley-Liss, Inc.

Purified HL-A antigen bearing cell membrane components were prepared from human lymphoid cells by papain digestion and physicochemical fractionation. Rabbits immunized with these components produced antisera which had high cytotoxic titers against human lymphoid cells and other human tissue culture cells. The cytotoxicity was inhibited only by those membrane fractions which contained HL-A activity. Absorption and cytotoxicity inhibition studies showed that the antisera possessed antibodies against antigens shared by humans and monkeys, antigens common to different human tissues, lymphoid antigens and allotypic antigens. To determine if the heterologous antisera reacted with immunoglobulin-like receptor sites on the lymphoid cell surface, purified human immunoglobulins were tested for their ability to inhibit the cytotoxic antisera. The evidence obtained from complement and noncomplement dependent systems indicated that the surface components recognized by the antisera did not include immunoglobulins. Addition of IgM to the complement dependent cytotoxicity assay, however, did interfere with the reaction by binding complement.

To determine the fate and distribution of chromium during lactation, six lactating women (25-38 y old) were given three doses of the tracer 53Cr (7.55 micromol/d, or 400 microg/d) on days 1, 2, and 3 of the study. Diet records, blood samples taken while subjects were fasting, and 24-h composite milk and urine samples were collected from day 0 to day 6. Fasting blood samples, morning milk samples, and 24-h urine samples were also collected on days 8, 10, 15, 30, 60, and 90. 53Cr and natural and total chromium concentrations in biological fluids were measured with gas chromatography-mass spectrometry and total urinary chromium was measured with atomic-absorption spectrometry. 53Cr was detectable in serum 2 h after dosing and continued to be detected from day 30 to day 60. Changes in total serum chromium concentration in response to the oral dose suggested that chromium concentrations in blood were not tightly regulated. 53Cr was not detected in breast milk and no significant changes in natural chromium concentration in milk were observed in response to the oral doses, suggesting that breast-milk chromium concentrations are independent of intake. The estimated chromium intake of exclusively breast-fed infants was 2.5 nmol/d (0.13 microg/d), below the lower end of the range of estimated safe and adequate daily dietary intakes (10-40 microg/d) for infants 0-6 mo of age. The baseline chromium concentration in urine and the minimum 53Cr absorption in lactating women were comparable with values for nonpregnant, nonlactating subjects. Chromium losses in breast milk do not appear to be compensated for via increased absorption or decreased excretion.

Both exercise and chromium exert beneficial effects on insulin function. The mechanism by which exercise improves insulin response may involve an alteration in Cr metabolism. To determine the effects of acute and chronic resistive exercise on urinary Cr losses, we measured the effects of acute resistive exercise and 16 wk of resistive exercise training on urinary Cr losses of 10 men 53-63 y of age. Subjects consumed diets in compliance with the American Heart Association Phase I diet with a Cr content of 30 +/- 4 microg/d. Sixteen weeks of resistive exercise training led to approximately 40% increases in upper and lower body strength, increases in fat-free mass and decreases in the percentage of body fat. An enriched stable isotope of Cr, 53Cr, was employed to differentiate the exogenously administered Cr from the native endogenous Cr. Both acute and chronic resistive exercise increased 53Cr losses. These data demonstrate that the improvements in body composition due to resistive exercise are associated with increased urinary Cr losses that are consistent with increased absorption.

B cells are susceptible to Fas ligand (FasL)+ CD4+ Th1 cell–mediated apoptosis. We demonstrate that blocking the interactions between lymphocyte function associated (LFA)-1 and intercellular adhesion molecule(ICAM)-1 and ICAM-2 completely suppresses Fas-dependent B cell lysis. Antibodies to CD2 and CD48 partially suppress B cell apoptosis, whereas anti-B7.1 and anti-B7.2 antibodies have no effect. Also, B cells from ICAM-1–deficient mice are resistant to FasL+ T cell–mediated death. Our results suggest that LFA-1/ICAM interactions are crucial for Th1 cell–mediated B cell apoptosis and may contribute to the maintenance of B cell homeostasis in vivo.

There has been a resurgence of interest in the use of metal on metal bearings in total hip arthroplasty. Although the use of metal on metal bearing couples would eliminate or substantially reduce particulate polyethylene generation (depending on the presence or absence of polyethylene in the implant system), there is concern about the potential for increased particulate and ionic metal generation in comparison with polyethylene on metal bearings. These metallic degradation products may be transported away from the implant site and distributed systemically. Chromium concentrations in the serum and urine and cobalt concentrations in the serum were measured in subjects with cobalt chromium alloy metal on metal total hip replacements and in controls without implants. Eight subjects with long term (> 20 years) McKee-Farrar total hip replacements had 9-fold elevations in serum chromium, 35-fold elevations in urine chromium, and at least 3-fold elevations in serum cobalt concentrations in comparison with controls. Six subjects with short term (< 2 years) metal on metal surface replacement arthroplasties had 3-fold elevations in serum chromium, 4-fold elevations in urine chromium, and 4-fold elevations in serum cobalt concentrations in comparison with subjects with McKee-Farrar implants. Although the toxicologic importance of these trace metal elevations has not been established, serum and urine metal concentrations may be useful markers for the tribologic performance of metal on metal bearings.

NK-92, a permanent natural killer (NK) cell line, shows cytotoxicity against a variety of tumors and has been tested in a phase I trial. We tested the toxicity of NK-92 and chemotherapy drugs against the stem cell capacity of the acute leukemia cell line, KG1. While the chromium-release assay is the most common method for assessing cytotoxicity of immune effectors, and flow cytometry is increasingly used, the relationship of either assay to clonogenic readouts remains unknown.KG1 was assessed for stem cell frequency by serial dilution, single-cell sorting and colony growth in methylcellulose. KG1 was sorted into CD34(+) CD38(+) and CD34(+) CD38⁻ populations and recultured in liquid medium or methylcellulose to determine the proliferative capacity of each fraction. Cytotoxicity of NK-92, daunorubicin and cytarabine against KG1 was measured using the chromium-release assay, flow cytometry and clonogenic assays.The culture-initiating cell frequency of whole KG1 was between 1 in 100 to 1000 by serial dilution and single-cell sorting. Although a rare (1-3%) CD34(+) CD38⁻ population could be demonstrated in KG1, both fractions had equivalent proliferative capacity. The cumulative flow cytotoxicity assay was more sensitive than the chromium-release assay in detecting target cell killing. At a 10:1 ratio NK-92 eliminated the clonogenic capacity of KG1, which was not predicted by the chromium-release assay.Clonogenic assays provide a more sensitive means of assessing the effect of a cytotoxic agent against putative cancer stem cells within cell lines, provided that they grow well in liquid culture medium or methylcellulose.

One new approach to cancer therapy is based on the adoptive transfer of tumor-specific cytotoxic T cells and anti-CD25 antibodies. In the present study, CD8+ and IFN-gamma secreting T lymphocytes (CTLs) were enriched as tumor-specific cytotoxic T cells from spleen lymphocytes of mice bearing the Renca tumor (a murine renal carcinoma line originating from a BALB/c mouse) after stimulation with tumor cells. An anti-CD25 IL-2Ralpha(anti-CD25) mAb from hybridoma PC61 was used for depletion for CD4(+)CD25(+) regulatory T (Treg) cells. Treatment-efficacy for tumor-bearing mice was compared using 4 systems: 1, whole spleen lymphocytes stimulated with tumor cells in vitro from tumor-bearing mice; 2, CTLs; 3, anti-CD25 mAbs; 4, CTLs and anti-CD25 mAbs. At the 50th day after tumor inoculation, in the group which received anti-CD25 mAb for depletion of T cells and inoculation of CTLs, tumors had disappeared and no re-growth was observed. In contrast, all mice of the non-treated and other three groups, treated with whole spleen cells alone, CTLs alone and anti-CD25 mAb alone, had died. These results showed that a combination of Treg cell-depletion using anti-CD25 mAbs and CTL administration is a feasible approach for treatment of cancers which warrants further exploration in the clinical setting.

Gutta-percha (GP) has been the most widely used root canal filling material because of its well-known low toxicity. The inertness of GP, however, was challenged recently. The purpose of this study was to evaluate the toxicity of marketed endodontic GP using the radiochromium release test. Fourteen commercially available and three experimental GP brands were tested. Raw GP, zinc oxide, and barium sulfate, which were considered major components of GP points, and zinc ions were also evaluated. The material was spread to cover the bottom of testing wells after being dissolved in chloroform or warmed. A labeled suspension of L929 cells was added to the wells. After incubation at 37 degrees C for 4 and 24 h, extracellular radiochromium in the culture medium was measured and calculated in percentage of the total intracellular label. Spontaneous release of radiochromium was used as control and the results were considered to be within normal limits either at 4 or 24 h. All chloroform-dissolved GP showed low toxicity at 4 h, whereas warmed GP showed statistically significant differences at 4 h. Both dissolved and warmed GP were toxic at 24 h. The raw materials and barium sulfate were not toxic, whereas zinc oxide and zinc ions showed marked toxicity. All GP points tested were toxic at longer observation periods, and the toxicity was attributed to leakage of zinc ions into the fluids.

Irritable bowel syndrome (IBS) is a heterogeneous condition and defined according to symptoms. Low-grade inflammation has been associated with IBS, particularly that following infection, but whether altered intestinal permeability profiles relate to irritable bowel subtype or onset is uncertain. Our aim was to compare small and large intestinal permeability in various subtypes of IBS to healthy controls.Intestinal permeability was measured using 1.8 MBq of 51Cr-EDTA and collecting urine over 24 h; Study 1: patients with diarrhea-predominant postinfectious IBS (N=15), constipation-predominant IBS (N=15), and healthy controls (N=15); Study 2: two groups of diarrhea-predominant IBS (D-IBS), one with a history of onset after acute gastroenteritis (postinfectious) (N=15) and the other without such a history (nonpostinfectious) (N=15) both compared with healthy controls (N=12).Permeability expressed as percentage of total dose excreted in urine (median [inter-quartile range]). Study 1: Proximal small intestinal permeability was increased in postinfectious IBS (0.19 [0.12-0.23]) in contrast to constipated IBS (0.085 [0.043-0.13]) and controls (0.07 [0.035-0.19]) (p=0.02). IBS patients with eczema, asthma, or hayfever had increased proximal small intestinal permeability compared with IBS patients without atopy (p=0.02). Study 2: Small intestinal permeability was greater in nonpostinfectious diarrhea-predominant IBS (0.84 [0.69-1.49]) compared with postinfectious IBS (0.43 [0.29-0.63], p=0.028) or controls (0.27 [0.2-0.39]), p=0.001).Small intestinal permeability is frequently abnormal in diarrhea-predominant IBS. Those without a history of infectious onset appear to have a more severe defect.

Glucagon like peptide-1 (7-36) (GLP-1), one of the gastrointestinal (GI) regulatory peptide, is known to act as a stress related brain neurotransmitter mediating GI function. Central administration of GLP-1 inhibits gastric emptying. However, little is known about the effect of central GLP-1 on colonic transit. Effects and mechanism of GLP-1 on colonic transit were investigated in conscious rats. Immediately after intracerebroventricular (icv)-injection of GLP-1, 51Cr was applied via the catheter positioned to the proximal colon. 90 min after 51Cr injection, rats were euthanized and the colon was removed and divided into 10 equal segments. The radioactivity of each segment was counted and the geometric center (GC) was calculated. Icv-injection of GLP-1 (0.3-3 nmol) dose-dependently accelerated colonic transit [(GC: 4.4+/-0.2 in controls, 7.8+/-0.5 in GLP-1 (3 nmol)]. In contrast, intraperitoneal (ip)-injection of GLP-1 (3 nmol) did not modify colonic transit. Icv-injection of GLP-1 (3 nmol)-induced acceleration of colonic transit was attenuated by vagotomy, atropine and hexamethonium, but not by guanethidine. Icv-injection of GLP-1 (3 nmol)-induced acceleration of colonic transit was abolished by corticotropin releasing factor (CRF) antagonist, astressin. Restraint stress-induced acceleration of colonic transit was abolished by a selective GLP-1 receptor antagonist, exendin. These results indicate that the endogenous GLP-1 is involved in mediating stress-induced alteration of colonic transit via a central CRF and peripheral cholinergic pathways in rats.