Comparison of urine albumin creatinine ratio with the pediatric index of mortality 2 score for prediction of pediatric intensive care unit outcomes

Background

Predicting morbidity and mortality in a pediatric intensive care unit (PICU) is of extreme importance to make precise decisions for better outcomes.

Aim

We compared the urine albumin creatinine ratio (ACR) with the established PICU score, pediatric index of mortality 2 (PIM 2) for predicting PICU outcomes.

Methods

This cross-sectional study enrolled 67 patients admitted to PICU with systemic inflammatory response syndrome. Urine ACR was estimated on admission, and PIM 2 score was calculated. ACR was compared with PIM 2 for PICU outcome measures: the need for inotropes, development of multiple organ dysfunction syndrome (MODS), duration of PICU stay, and survival.

Results

Microalbuminuria was found in 77.6% of patients with a median ACR of 80 mg/g. ACR showed a significant association with the need for inotropes (p < 0.001), MODS (p = 0.001), and significant correlation to PICU stay (p 0.001, rho = 0.361). The area under the receiver operating characteristic curve for ACR (0.798) was comparable to that of PIM 2 (0.896). The cutoff value of ACR derived to predict mortality was 110 mg/g. The study subjects were divided into 2 groups: below cutoff and above the cutoff. Outcome variables, inotrope use, MODS, mortality, and PICU stay compared between these subgroups, were statistically significant.

Conclusion

ACR is a good predictor of PICU outcomes and is comparable to PIM 2 for mortality prediction.

Comparative validity of microalbuminuria versus clinical mortality scores to predict pediatric intensive care unit outcomes

BACKGROUND

Predicting the prognosis of patients admitted to the pediatric intensive care unit (PICU) is very important in determining further management and resource allocation. The prognostication of critically ill children can be challenging; hence, accurate methods for predicting outcomes are needed.

PURPOSE

To evaluate the role of microalbuminuria at admission as a prognostic marker in comparison to standard Pediatric Risk of Mortality (PRISM) and Pediatric Logistic Organ Dysfunction (PELOD) mortality scores in children admitted to the PICU.

METHODS

This cross-sectional study was conducted from January 2015 to October 2016. Eighty-four patients aged 1 month to 18 years admitted to the PICU of teaching hospitals for more than 24 hours were enrolled by convenience sampling method. Microalbuminuria was estimated by spot urinary albumin-creatinine ratio. PRISM and PELOD scores were calculated using an online calculator. Outcome measures were PICU length of stay, inotrope usage, multiorgan dysfunction, and survival. ACR was compared with mortality scores for predicting survival.

RESULTS

Microalbuminuria was present in 79.8% with a median value of 85 mg/g (interquartile range, 41.5-254 mg/g). A positive correlation was found between albumin-creatinine ratio and PICU length of stay (P=0.013, r=0.271). Albumin-creatinine ratio was significantly associated with organ dysfunction (P=0.004) and need for inotropes (P=0.006). Eight deaths were observed in the PICU. The area under the curve for mortality for albumin-creatinine ratio (0.822) was comparable to that for PRISM (0.928) and PELOD (0.877). Albumin-creatinine ratio >109 mg/g predicted mortality with a sensitivity of 87.5% and specificity of 63.2%.

CONCLUSION

Microalbuminuria is a good predictor of PICU outcomes comparable with mortality scores.

Pulmonary dysfunction in children with beta thalassemia major in relation with iron overload - a cross sectional hospital based study

Background: Previously many patients with thalassemia major died from severe anemia during first decade, but with modern transfusion therapy many now survive beyond childhood. Because of such therapy, however excessive iron deposition occurs in lungs and causing respiratory dysfunction. Respiratory impairment occurs because of defective chelation and repeated transfusions. Objectives: To a) study pattern of respiratory impairment using spirometry, b) estimate iron overload by measuring serum ferritin levels, c) correlate a&b. Methodology:Thalassemia children >7year, on regular blood transfusion were included in the study after getting institutional ethical clearance .Standardised pulmonary function test was done using spirometry. Iron overload was assessed using serum ferritin levels. Severity of pulmonary dysfunction was correlated with serum ferritin levels. Results:Total of 42 children were included 62% were males and 38% were females (with median age 12yrs). By spirometry 95% had restrictive pattern of respiratory dysfunction. Mean ferritin value was 4152. Out of them10 (23.8%) mild, 25(59%) moderate and 5(12%) severe dysfunction based on FEV1 and FVC. The mean ferritin values in severe respiratory dysfunction is 6275 which is significantly higher when compared to moderate (4249) and mild (3066) pattern of respiratory dysfunction. None of the children had evidence of CCF. Significant correlation (p value=0.003) was found between severity of pulmonary dysfunction with ferritin values and also with weight of the child (p value=0.007). No other significant correlation found between severity pattern and transfusion index, age or height. Conclusion:Restrictive pattern is most common pulmonary dysfunction seen in chronic iron overloaded thalassemia major children. Regular blood transfusions with adequate chelation decrease incidence of pulmonary dysfunction. Screening of all thalassemia children using spirometry is need of the hour. DOI: http://dx.doi.org/10.3126/ajms.v6i5.11782Asian Journal of Medical Sciences Vol.6(5) 2015 47-50

Combined effects of arginine and hydroxyurea on BFU-E derived colony growth and HbF synthesis in erythroid progenitors isolated from sickle cell blood

Hydroxyurea (HU) increases HbF synthesis in sickle cell disease (SCD). Recent studies suggest HU-induced HbF synthesis is mediated through a NO-cGMP pathway. Since arginine is the main precursor of NO, we investigated the effects of arginine and HU mixtures on HbF synthesis and burst forming unit erythroid (BFU-E) proliferation. Mixtures of HU (0, 15, 25, 100μM) and arginine (0, 25, 50, and 100μM) resulting in optimal HbF synthesis and minimal HU-induced cytotoxicity in erythroid progenitors were determined. HU dose-dependently attenuated growth of BFU-E colonies and stimulated HbF synthesis. In contrast, arginine dose-dependently increased BFU-E colonies without affecting HbF synthesis. Furthermore, arginine at concentrations >100μM in combination with varying concentrations of HU, decreased HbF synthesis compared to HU controls. HU, 15-25μM, in combination with 25-50μM arginine not only minimized cytotoxicity, but also increased HbF synthesis when compared with HU controls. NG-nitro-L-arginine-methyl ester (L-NAME; 100μM), a nitric oxide synthase inhibitor, attenuated the effects of HU+arginine on HbF synthesis compared to HU and HU+arginine controls. These results suggest HU+arginine-induced HbF synthesis in human erythroid progenitors is NO dependent. The synergistic effect on HbF synthesis seen with combinations HU+arginine is an important observation in understanding potential therapeutic uses of HU and arginine.

Erk pathway inhibitor U0126 induces gamma-globin expression in erythroid cells

Fetal hemoglobin (HbF) induction is an effective approach to improve clinical symptoms in sickle cell disease. Understanding molecular mechanisms for gamma-gene re-activation will aid efforts to design lead compounds. A potential inhibitory role for the extracellular signal-regulated kinase (ERK) mitogen-activated protein kinase (MAPK) pathway in gamma-gene expression has been suggested recently. Therefore, we determined the ability of U0126, a selective inhibitor of MEK1/2 the upstream activators of ERK, to re-activate gamma-globin expression. K562 stable lines over-expressing constitutively active MEK1 were established. A significant increase in ERK phosphorylation was observed and gamma-gene expression was silenced concomitantly, however U0126 attenuated this effect. Studies in human erythroid progenitors confirmed the ability of U0126 to induce HbF. Cellular mechanisms for the inhibitory role of ERK signaling in drug-mediated HbF induction will be discussed.

Fetal hemoglobin induction by the histone deacetylase inhibitor, scriptaid

Many different classes of drugs induce fetal hemoglobin (HbF) including histone deacetylase (HDAC) inhibitors such as butyrate and trichostatin A. Although these agents induce gamma-globin expression in culture many are ineffective in vivo, therefore research efforts continue to identify clinically useful fetal globin inducers. We and others demonstrated a role for p38 mitogen activated protein kinase (MAPK) in gamma-globin promoter activation by HDAC inhibitors. In this study we determined the ability of scriptaid, a novel HDAC inhibitor, to induce gamma-globin expression via p38 MAPK signaling. Scriptaid induced gamma-globin in K562 cells and human erythroid progenitors. Furthermore the p38-selective inhibitor SB203580 completely reversed the ability of scriptaid to induce HbF. To test the potential efficacy of scriptaid in humans, in vivo studies were completed in beta-YAC transgenic mice where the gamma-gene is completely silenced. Scriptaid induced reticulocytosis and human gamma-globin mRNA synthesis. At a concentration of 1 mg/kg/day given by intraperitoneal injections twice weekly we observed a significant 1.8-fold increase in gamma-globin mRNA transcripts. The potential for scriptaid as a treatment option for sickle cell disease will be discussed.

Evaluation of adnexal masses by ultrasound and fine needle aspiration cytology

Forty Eight cases of adnexal masses were subjected to ultrasound and FNAC. In this study, FNAC could differentiate benign and malignant adnexal masses in 98% of cases where as ultrasound was successful in 85% of cases. FNAC is a safe simple, rapid & reliable investigation. The complex adnexal masses present a diagnostic challenge with particular reference to the findings predictive of malignancy.

Iron deficiency alters the progression of mitogen-treated murine splenic lymphocytes through the cell cycle

The influence of iron deficiency on the progression of mitogen-treated splenic lymphocytes through the cell cycle was studied in 16 control, 16 pair-fed, 15 iron-deficient (ID) and 16 ID mice that were repleted for up to 3 d (R3). The test and control diets differed only in iron concentrations (0.09 vs. 0.9 mmol/kg). When mice were killed (68 d of feeding), the hemoglobin concentration and liver iron stores of ID and R3 mice were <50% those of control mice (P < 0.05). Iron deficiency did not reduce the percentage of CD3(+) cells, but decreased CD3(+) cells/mg spleen (P < 0.05). In concanavalin A-treated and nonactivated cultures, there were no significant differences among groups in the percentages of cells in resting phase of the cell cycle (G0) to cell cycle initiation phase (G1), DNA synthesis phase (S) and exit from the S phase (G2) to mitosis phase (M) phases. In anti-CD3 and anti-CD3/anti-CD28-treated cultures, higher percentages of lymphocytes from ID and R3 mice than those from control and pair-fed mice were in the G0--G1 phase (P < 0.05). Conversely, lower percentages of activated cells from ID and R mice than those from control and pair-fed mice were in S and G2--M phases (P < 0.05). Incubation of lymphocytes with mitogens decreased the percentages of cells in G0--G1 phase from 90% to 80% in control and pair-fed but not in ID and R3 mice (P < 0.05). In activated cells, indices of iron status negatively correlated with the percentages of cells in G0--G1 (r = -0.306 to -0.597) but positively with those in S (r = 0.166--0.511) and G2--M phases (r = 0.265-0.59; P < 0.05). Data suggest that altered cell cycle progression likely contributes to impaired lymphocyte proliferation usually associated with iron deficiency.

Mechanism for fetal hemoglobin induction by hydroxyurea in sickle cell erythroid progenitors

Hydroxyurea (HU) is a widely used cytotoxic agent that is known to induce fetal hemoglobin (HbF) production and is presently used to ameliorate the severity of pain episodes in patients with sickle cell anemia (HbSS). Previously we have shown that HU inhibits growth of burst forming unit-erythroid (BFU-E) colonies in a dose-dependent manner, while fetal hemoglobin levels were increased. In the present report, we extended our analysis demonstrating the number of S phase cells is significantly higher for HbSS patients that respond to HU therapy. Studies were completed in vitro using erythroid progenitors derived from umbilical cord samples or peripheral blood from patients with HbS-hereditary persistence of fetal hemoglobin (HbS-HPFH) or HbSS disease. The effect of HU on (a) S phase erythroid progenitors, (b) BFU-E colony growth, (c) HbF levels in BFU-E colonies, and (d) total cellular RNA synthesis was analyzed in vitro for the three groups. The level of S phase erythroid progenitors was similar for all three groups and BFU-E colony growth was inhibited 92-94% for all samples in a dose-dependent manner. The HbF levels were increased in BFU-E colonies from HbSS patients (control, 4.0% +/- 1.15% vs. +HU, 22.67% +/- 2.03%) whereas HbF levels were decreased in BFU-E colonies derived from umbilical cord samples (control, 80% +/- 9.07% vs. +HU, 35.7% +/- 4.81%) or HbS-HPFH patients (control, 49.67% +/- 3.84% vs. +HU, 23.3% +/- 0.88%). Total RNA synthesis measured by 3H-uridine incorporation increased with increasing concentrations of HU; however, actinomycin D inhibited HU-induced RNA synthesis. These results suggest that HU can inhibit an active globin gene without preference and that newly synthesized RNA is under transcriptional control mechanisms.

Hyperhomocysteinemia in type 2 diabetes mellitus: cardiovascular risk factors and effect of treatment with folic acid and pyridoxine

OBJECTIVE

To determine whether hyperhomocysteinemia (HH) exacerbates other cardiovascular risk factors and markers of coagulation and hemostasis in patients with type 2 diabetes mellitus (DM) and whether treatment of HH with vitamins will alter these risk factors.

METHODS

We measured several cardiovascular risk factors and markers of coagulation and hemostasis in patients with type 2 DM with and without HH. We also treated patients with type 2 DM and coexistent HH with high doses of folic acid and pyridoxine to determine whether this treatment would lower plasma total homocysteine concentrations as well as correct other associated cardiovascular risk factors in this population.

RESULTS

Plasma levels of plasminogen activator inhibitor type 1 and fibrinogen were significantly higher in all patients with DM in comparison with control subjects (P<0.01), whether they had HH or not. No significant difference was noted between the two groups of patients with DM. The presence of hypertension and microalbuminuria did not lead to a higher plasma total homocysteine. After treatment with folic acid, 15 mg daily, and pyridoxine, 600 mg daily, fasting (basal) plasma total homocysteine declined significantly in patients with DM from 12.3 +/- 2.9 micromol/L to 9.1 +/- 1.1 micromol/L (P<0.01). The peak post-methionine load plasma total homocysteine in the patients with DM decreased from 39.9 +/- 11.4 micromol/L to 30.4 +/- 6.5 micromol/L (P<0.05). Neither fasting nor peak plasma total homocysteine changed in normal subjects. None of the cardiovascular risk factors measured changed significantly with the vitamin treatment.

CONCLUSION

The coexistence of type 2 DM and HH does not lead to an exacerbation of abnormalities in the measured variables of coagulation and hemostasis. Treatment with high doses of folic acid and pyridoxine lowers the plasma total homocysteine significantly but does not improve any of the associated cardiovascular risk factors that we measured. Long-term clinical trials should be conducted to determine whether high-dose vitamin treatment will diminish the increased morbidity and mortality associated with cardiovascular disease in patients with type 2 DM.

A study of lupus anticoagulant in unexplained fetal wastage

Lupus Anticoagulant, first discovered in patients of SLE, is now known to be associated with a wide spectrum of diseases. The presence of LA is associated with adverse fetal outcome in an obstetric population. In the present series the incidence of LA was found to be 16.6% and 80% of LA positive subgroup had an unsuccessful outcome.

In vivo and in vitro iron deficiency reduces protein kinase C activity and translocation in murine splenic and purified T cells

We investigated the effects of iron deficiency anemia, iron repletion, and iron chelation by deferoxamine on protein kinase C (PKC) activity, an enzyme that plays a crucial role on T lymphocyte proliferation. The study involved 23 control (C), 18 pairfed (PF), and 24 iron deficient (ID) mice or ID mice that were repleted for 3 (n = 14), 7 (n = 17), or 14 (n = 14) days. The low iron (0.09 mmol iron/kg) and iron-supplemented (0.9 mmol iron/kg) diets were fed to mice for 53 days. Mean hemoglobin, hematocrit, and liver iron stores of ID mice were one third of those of C mice. Lymphocyte proliferation was reduced (P < 0.05) in spleen and purified T cells in ID but not PF mice. In concanavalin A, phytohemagglutinin, and anti-CD3 antibody-treated and untreated cells that were incubated in serum-free and serum-containing medium, PKC activity was significantly (P < 0.05) reduced in ID but not PF mice and returned to normal before correction of anemia. In mitogen-treated cells, while the ratios of membrane-bound to cytosol activity increased nearly seven-fold (from 0.4-0.63 in resting cells to 1.43-7.23) in spleen cells from C, PF, and repleted mice and 11-fold in T cells (P < 0.005), they remained below 1 in ID mice suggesting reduced translocation. In vitro iron chelation by deferoxamine for 120 min prior to cell activation reduced (P < 0.05) PKC activity by 46-60% in C and PF and 28-53% in ID mice. The data suggest that: 1) it is iron-deficiency but not anemia or differences in the proportion of immunocompetent T cells that reduced PKC activity in cells from ID mice; 2) reduced PKC translocation may play an important role on altered lymphocyte proliferation and associated functions in iron-deficient individuals.

Iron deficiency reduces the hydrolysis of cell membrane phosphatidyl inositol-4,5-bisphosphate during splenic lymphocyte activation in C57BL/6 mice

Iron deficiency impairs lymphocyte proliferation in humans and laboratory animals by unknown mechanisms. In this study, we investigated whether this alteration can be attributed in part to impaired hydrolysis of cell membrane phosphatidyl inositol-4, 5-bisphosphate (PIP2), a required early event of T-lymphocyte activation. The study involved 46 iron-deficient (ID), 26 control (C) and 23 pair-fed (PF) mice, and ID mice that were repleted for 3 (n = 16), 7 (n = 17) or 14 d (n = 18). Mice were killed after 40-63 d (mean, 48 d) of consuming the test diet (0.09 mmol/kg iron) or the control diet (0.9 mmol/kg). The mean (+/-SEM) hemoglobin concentrations were 57 +/- 16.7, 176 +/- 2.6 and 181 +/- 9.7 g/L for ID, C and PF groups, respectively. After splenic lymphocytes were labeled in vitro with 3H-myoinositol for 3 h, PIP2 hydrolysis was estimated by measuring the radioactivity recovered as a mixture of inositol mono-, di- and triphosphate (IP) from concanavalin A (0, 1, 2.5, 5 and 10 mg/L) activated cells. Although cells from ID mice and those from mice repleted for 3 d incorporated slightly more radioactivity in cellular phospholipids than did cells from C or PF mice, less (P < 0.005) was recovered as IP than in controls, suggesting impaired conversion of the precursor to PIP2. At almost all incubation periods (10-120 min) and mitogen concentrations, the rate of PIP2 hydrolysis expressed as the ratio of radioactivity obtained in Con A-treated to untreated cells was significantly (P < 0.05) reduced in cells from ID mice compared with those obtained from C and PF mice. For cells that were activated for 60 min or less, iron repletion for 14 d significantly (P < 0.05) improved the rate of PIP2 hydrolysis. PIP2 hydrolysis positively and significantly (P < 0.05) correlated (r = 0.27-0.56) with indicators of iron status. Mitogenic response was also significantly (P < 0.05) reduced in ID but not PF mice, and it was corrected by iron repletion for 3, 7 or 14 d. Lymphocyte proliferation positively (r = 0.27-0.37, P < 0.01) correlated with indices of iron status and IP ratios. The data suggest that reduced PIP2 hydrolysis contributes to impaired blastogenesis in iron deficiency.

Multiple primary visceral malignancy--a review with report of two cases

Multiple primary cancers are being reported with increasing frequency in recent years, the frequency varying from 0.3 to 4.3% in different studies. A combination of primary cancer of larynx and lung is the most common followed by malignant neoplasm involving lip-larynx, skin-larynx, skin-lung, breast-ovary and breast-endometrium. Two interesting cases of rare combinations of primary cancers are being presented. In the first case primary adenocarcinoma of the gall bladder was associated with appendiceal adenocarcinoma. In the second case primary malignant papillary serous cystadenocarcinoma of right ovary and squamous cell carcinoma of cervix uteri were found.

BFU-E colony growth in response to hydroxyurea: correlation between in vitro and in vivo fetal hemoglobin induction

Patients with sickle-cell anemia treated with hydroxyurea may have significant reduction in frequency and severity of pain episodes. However, previous clinical trials show a variable response to hydroxyurea. Criteria which can be used to select patients who are likely to respond to hydroxyurea treatment would be useful. Our laboratory has previously demonstrated an inverse linear relationship between the total number of burst-forming unit-erythroid (BFU-E) colonies and fetal hemoglobin levels in sickle-cell patients treated with hydroxyurea. In the present report, an in vitro cell culture system was established to evaluate the effects of hydroxyurea on BFU-E colony growth and induction of fetal hemoglobin production. Five Hb SS patients who were not previously treated with hydroxyurea and three Hb SS patients who failed to respond to hydroxyurea treatment were included in the study. The results show that the number of BFU-E colonies is decreased from 153.7 to 7.2 per 3 x 10(5) mononuclear cells, whereas fetal hemoglobin levels were increased from 5.1 to 19.4% in the presence of hydroxyurea in vitro in cultured erythroid progenitors, which were derived from 5 patients before treatment. The number of BFU-E colonies decreased from 153.7 to 2.0 per 3 x 10(5) mononuclear cells in the in vitro cultures obtained from serial peripheral blood samples over a 9- to 20-week period of oral hydroxyurea therapy. A simultaneous rise in fetal hemoglobin level from 10.2 to 28.6% in the peripheral blood over the same period of hydroxyurea therapy was also observed. Our results demonstrate that the increase in fetal hemoglobin levels in cells treated with hydroxyurea in vitro is comparable to the rise of fetal hemoglobin production following hydroxyurea therapy in these patients. On the contrary, these findings were not observed in three previously non-responsive sickle-cell patients. These results suggest that the changes in number of BFU-E colonies and fetal hemoglobin levels after in vitro exposure to hydroxyurea may be a useful approach to select sickle-cell patients who will respond to hydroxyurea therapy.

Oxidative stress in diabetic macrovascular disease: does homocysteine play a role?

BACKGROUND

Non-insulin-dependent diabetes mellitus (NIDDM) and hyperhomocysteinemia are both associated with increased lipid peroxidation (oxidative stress). This may contribute to the accelerated vascular disease associated with these conditions. It is not known whether the coexistence of elevated homocysteine levels will stimulate oxidative stress further than that caused by diabetes alone.

METHODS

Plasma concentrations of thiobarbituric acid reactive substances (TBARS), an index of lipid peroxidation, were measured in patients with NIDDM who had previously had a methionine load test; some of the patients had hyperhomocysteinemia.

RESULTS

Plasma TBARS concentrations were elevated in diabetics with vascular disease. The additional presence of hyperhomocysteinemia was not associated with a further increase in plasma TBARS concentrations.

CONCLUSIONS

Lipid peroxidation is increased in patients with diabetes mellitus and macrovascular disease and is not further elevated by the coexistence of elevated homocysteine levels. It is possible that diabetes maximally stimulates oxidative stress and any further acceleration of vascular disease in patients who have coexistent hyperhomocysteinemia is mediated through mechanisms other than lipid peroxidation.

Recent advances in the treatment of type II diabetes mellitus

Diabetes mellitus needs to be managed early to prevent the onset and progression of complications. Diet and exercise may not be sufficient to achieve and maintain good glycemic control. Currently, no pharmacologic agent addresses all of the fundamental abnormalities in the pathogenesis of type II diabetes mellitus. However, the newer agents do not exacerbate the hyperinsulinemia that often occurs with type II diabetes, and they may help reduce the risk of cardiovascular disease that is associated with high insulin levels. Two of these agents, metformin and acarbose, have recently become available in the United States for the treatment of type II diabetes. With the availability of agents that differ in their mechanisms of action and side effect profiles, regimens can be individualized to address the variety of pathophysiologic abnormalities in type II diabetes. For this purpose, agents can be used alone or in combination.

Mechanism of differentiation of human erythroleukaemic cell line K562 by hemin

The human erythroleukaemic cell line K562, in response to various chemical agents, undergoes differentiation and exhibits exclusive production of fetal and embryonic haemoglobins. In this study we have compared the efficiency of natural growth factors interleukin-3 and erythropoietin and three chemical inducers such as dimethyl sulfoxide (DMSO, 1.9%), phorbol-12-myristate-13-acetate (PMA, 50 ng/ml) and hemin (25 microM) on growth and differentiation of these cells. Erythropoietin significantly stimulated the growth of K562 cells (P<0.0001), while interleukin-3 did not (P = 0.2783). However, neither of these growth factors individually or together induced differentiation of K562 cells. Hemin appears to be more efficient than DMSO or PMA in differentiation of K562 cells as measured by benzidine positive cells (70% or more). The differentiation of K562 cells by hemin occurs independently of protein kinase-C activation and the arrest of DNA synthesis. In contrast, hemin significantly stimulated RNA and protein synthesis (P<0.0001) as measured by [3H]-uridine and [3H]-leucine incorporation respectively. Analysis of hemin-treated K562 nuclear extract on sodium dodecylsulphate gel electrophoresis showed that one protein band of molecular weight 70 kDa decreased after 48 h of incubation in the presence of 25 microM hemin. The disappearance of this protein can be prevented by cycloheximide (100 microg/ml) and actinomycin D (0.1 microg/ml) and thus indicating that the removal of 70 kDa protein seems to be dependent on RNA and protein synthesis. The regulatory role of 70 kDa protein in hemin-induced differentiation of K562 cells is discussed.

A novel nuclear protein which binds to G gamma and A gamma globin promoters and modulates hemoglobin synthesis in K562 cells

Nuclear extract of human erythroleukemic cell line K562 contains a 70 kDa protein which is gradually reduced when cells are induced to express globin genes by 25 microM hemin. When globin synthesis was inhibited by cycloheximide (100 micrograms/ml) or Actinomycin D (1 microgram/ml), the disappearance of this protein was prevented. The 70 kDa nuclear protein exhibited strong binding to G gamma and A gamma globin promoters but not to beta-globin promoter. This suggests that this 70 kDa nuclear protein may be involved in the regulation of fetal globin gene expression.

Impaired protein kinase C activation as one of the possible mechanisms of reduced lymphocyte proliferation in iron deficiency in mice

We investigated the effects of iron deficiency in mice on protein kinase C (PKC) activation, an enzyme required for optimal lymphocyte proliferation. C57BL/6 mice were fed either an iron-deficient diet (ID; 10 mg Fe/kg diet), a control diet (C; 50 mg/kg diet), or were pair fed (PF) to ID mice for 34 d. PKC activity was studied in spleen cells by histone phosphorylation. Iron deficiency significantly reduced cytosol activity in unstimulated cells and membrane-bound activity in cells stimulated by concanavalin A (Con A) or phorbol-12-myristate-13-acetate (PMA), and the ratio of membrane-bound over cytosol activity in mitogen-stimulated cells. In PF mice the ratio of membrane-bound activity to cytosol activity was greater than normal in Con A-treated cells and only slightly decreased in PMA-treated cells. PKC activity positively correlated with iron status. We conclude that reduced PKC activity and poor translocation results in aberrant signal transduction, which in turn might be responsible for the impaired lymphocyte proliferation associated with iron deficiency.

Effects of EGF and PMA on the growth and proliferation of IEC-6 cells

Proliferation of an epithelial line (IEC-6) derived from the crypts of rat jejunum was induced with epidermal growth factor (EGF). EGF enhanced synthesis of protein, RNA, and DNA in a dose-dependent manner. Protein synthesis increased within 6-12 hours of exposure to EGF and remained elevated for 72 hours. Maximal 3H-thymidine incorporation occurred 48 hours after addition of EGF. The stimulatory effect of EGF on 3H-thymidine incorporation was two-fold greater in serum-free media than in media containing fetal calf serum (FCS). In contrast to EGF, phorbol-12-myristate-13-acetate (PMA) decreased 3H-thymidine uptake by IEC-6 cells and had no effect on either protein synthesis or RNA synthesis. EGF did not alter protein kinase-C activity in IEC-6 cells whereas PMA induced enzyme activity: activity was translocated from cytosol to membrane. Moreover, the EGF-associated increase in 3H-thymidine uptake was not altered by amiloride. These data suggest protein kinase-C activation may not be involved in the proliferation of IEC-6 cells.

Evaluation of [3H]thymidine uptake method for studying growth of spiroplasmas under various conditions

[3H]thymidine uptake and colony counts are quantitative and inexpensive methods for studying Spiroplasma growth. Using these techniques, we demonstrated subtle effects on the growth of suckling mouse cataract agent of medium alterations, inoculum size, and freezing of cultures. In addition, suckling mouse cataract agent multiplied more actively under aerobic than under anaerobic conditions. These techniques have wide application for the study of Spiroplasma growth and will be useful for the development of a defined medium.

Effects of growth and differentiation inducing factors on protein kinase-C of cultured intestinal crypt cells

To assess the role of protein kinase-C (PK-C) in the growth and differentiation of small intestinal enterocytes, IEC-6 cells (a cell line derived from the crypts of rat small intestine) were incubated with factors known to induce growth (insulin, epidermal growth factor, gastrin, somatostatin and transferrin) or differentiation (transforming growth factor-beta, retinoic acid and phorbol 12-myristate 13-acetate (PMA)). Cell proliferation (3H-thymidine incorporation) and PK-C activity (Ca++/phospholipid dependent) were measured. Among growth promoting factors only epidermal growth factor, insulin and transferrin were associated with increased 3H-thymidine incorporation, and none of these agents induced PK-C activation as measured by its translocation from cytosol to membrane fraction. Of the differentiation inducing factors, only PMA translocated PK-C from cytosol to membrane. PMA also inhibited 3H-thymidine incorporation in a dose dependent manner. These results suggest that growth and proliferation of enterocytes occur independent of PK-C signal transduction.

Inhibition of T-lymphocyte activation by amiloride

The T-lymphocyte activation process involves a series of coordinately coupled biochemical events occurring in response to antigen or mitogen. These events have not been completely characterized. The present studies investigate the mechanism of protein synthesis during the initial phase of T-cell activation. Among the early biochemical changes, induction of protein synthesis was observed as early as 10 minutes after mitogen stimulation of T-lymphocytes. This early protein synthesis was inhibited by cycloheximide but was insensitive to actinomycin-D, indicating the presence of preformed mRNA in resting lymphocytes. Since early protein synthesis parallels the increase in protein kinase C activity in activated T-lymphocytes, these two biochemical events may be related. In the present report, amiloride, an inhibitor of Na+/H+ antiport and protein kinase C, significantly inhibited [3H]leucine and [3H]thymidine incorporation in a dose-dependent manner into phytohemagglutinin (PHA)-stimulated T-lymphocytes. Furthermore, when T-lymphocytes were stimulated by phorbol myristate acetate, a known activator of protein kinase C, a similar inhibition of protein and DNA synthesis by amiloride was observed. The partially purified cytosol fraction isolated from PHA-activated T-lymphocytes showed a 75% decrease in protein kinase C-mediated [32P] incorporation from ATP in the presence of 100 microM amiloride. These results suggest that the T-cell activation process following exposure to mitogens involves early protein synthesis, which may be mediated by protein kinase C.

Effect of polymyxin-B on T-lymphocyte protein synthesis

The role of protein kinase-C (PK-C) protein phosphorylation on the mitogen triggered responses of T-lymphocytes was examined by observing the effect of polymyxin-B (an inhibitor of PK-C) on mitogen induced protein and DNA synthesis. Polymyxin-B inhibited 3H-thymidine incorporation by PHA activated T-lymphocytes over a range of PHA concentrations. 3H-leucine incorporation by PHA activated T-lymphocytes was inhibited by polymyxin-B in a dose dependent manner. A partially purified PK-C fraction from polymyxin-B treated PHA activated T-lymphocytes demonstrated less than 25% of the phosphorylating activity of untreated lymphocytes. These results suggest that protein synthesis during the T-lymphocyte activation process is dependent on PK-C activity.

The effect of iron-deficiency anemia on cytolytic activity of mice spleen and peritoneal cells against allogenic tumor cells

The capacity of spleen and peritoneal cells from iron deficient mice, ad libitum fed control mice, and pair-fed mice to kill allogenic tumor cells (mastocytoma tumor P815) has been investigated. In the first study, mice were sensitized in vivo with 10(7) viable tumor cells 51 and 56 days after weaning. The capacity of splenic cells and peritoneal cells from sensitized and nonsensitized mice to kill tumor cells was evaluated 5 days after the second dose of tumor cells. At ratios of 2.5:1 to 100:1 of attacker to target cells, the percentage 51Cr release after 4 h of incubation was significantly less in iron-deficient mice than control and/or pair-fed mice (p less than 0.05). Protein-energy undernutrition in pair-fed mice had no significant effect. In the second study, spleen cells and enriched T cell fractions were incubated in vitro for 5 days with uv irradiated Balb/C spleen cells in a 2:1 ratio. The cytotoxic capacity against the same allogenic tumor cells was again evaluated. The percentage chromium release at different attacker to target cells was less than 30% in the iron-deficient group compared to either control or pair-fed supporting the results of in vivo sensitized cells. The possible mode of impairment of the cytotoxic capacity is discussed.

De novo purine nucleotide synthesis in the rat small and large intestine: effect of dietary protein and purines

This study assessed the pathway for de novo purine nucleotide synthesis in rat small intestinal and colonic mucosal cells, and determined the effects of dietary purines and protein on de novo purine nucleotide synthetic activity in the small intestine in vitro. Incubation of small intestinal mucosal scrapings with [14C]glycine failed to show an active pathway of de novo synthesis; in contrast, the colon showed incorporation of [14C]glycine into RNA. Rats fed a diet deficient in purines demonstrated increased incorporation of [14C]glycine into RNA-adrenine in small intestinal mucosal cells. Measurement of glutamine-amidophosphoribosyltransferase demonstrated that, regardless of the purine content of the diet, enzyme activity in the small intestine is significantly lower than in the colon or liver. The results indicate that, in the small intestine of the rat, there is an inactive de novo pathway of purine nucleotide biosynthesis that can be stimulated when purines are omitted from the diet.

Impairment of blastogenic response of splenic lymphocytes from iron-deficient mice: in vivo repletion

Iron-deficiency anemia impaired the blastogenic response of splenic lymphocytes and partially purified T cells to Concanavalin A and phytohemagglutinin. The response of splenic lymphocytes and partially B cells to bacterial lipopolysaccharide was also significantly impaired. Caloric restriction in pair-fed mice did not have any significant effect. Blastogenic response to the three mitogens was restored to normal after anemic mice were fed the regular diet containing 25 to 30 mg Fe/kg (FeSO4) for approximately 10 days. We also found that in the anemic mice the mean wet weights per 100 g of body of spleen, heart, brain, and kidney increased, while those of the thymus and liver decreased. In the pair-fed mice only the mean wet weight of the liver significantly decreased. There was a small but significant decrease in the white blood count and peripheral lymphocyte count in the anemic but not the pair-fed mice. The mechanism by which iron deficiency impairs the cell-mediated immune response is discussed.

Impaired intestinal localization of mesenteric lymphoblasts associated with vitamin A deficiency and protein-calorie malnutrition

We examined whether protein-calorie (PC) and vitamin A (VA) deficiencies altered the intestinal localization of mesenteric lymph node (MLN) lymphoblasts using an adoptive lymphocyte transfer method. MLN cells from donor rats were labelled in vitro with [125I]-deoxyuridine and injected i.v. into various recipients. Twenty-two to twenty-four hours after transfer of labelled cells prepared from PC-deficient donors, the percentage of radioactivity in the small intestine of normal recipients was two-thirds of that detected after transfer of cell obtained from normal donors. When donor cells were obtained from rats suffering both PC and VA malnourishment, this decrease was even greater, being only one-third of the normal donor cell control. Other experiments indicated that the defect in localization behaviour was associated with the donor blasts and not the recipient intestine. These findings suggest that defective localization in mucosal lymphoblasts may be a factor contributing to morbidity in malnourished populations.

Effects of iron deficiency anemia on delayed cutaneous hypersensitivity in mice

In the present study, the effect of iron-deficiency anemia on delayed cutaneous hypersensitivity was measured using weanling C57BL/6 female mice which were fed either an ad libitum control diet supplemented with 25 to 30 mg Fe/kg diet (FePO4), an iron-deficient test diet (5 to 6 mg Fe/kg diet), or pairfed control diet (25 to 30 mg Fe/kg diet). When skin sensitizing agent (dinitrofluorobenzene) was applied to these animals and skin responses were measured 3 to 5 days later, anemic mice showed a significantly decreased inflammatory skin response than either control or pairfed mice. Five days after sensitization, the animals were challenged with dinitrofluorobenzene painted on the right ear and an equal dose of only the solvent on the left ear followed by 125I-deoxyuridine injected intraperitoneally. The ratio of either total or DNA associated radioactivity incorporated into the right over the left ears was significantly lower in anemic mice than either control or pairfed mice. A single dose of Imferon injected 24 h before the recall dose of dinitrofluorobenzene restored the ratio of 125I-dUR incorporated in anemic mice without having any significant effect on either the control or pairfed groups. The results suggest that iron is not required for sensitization but is required for an effective inflammatory response.

Synthesis and processing of RNA by isolated human placental nuclei

Conditions for isolating intact and active nuclei from human term pacenta and for studying their transcription products are described. The isolated nuclei can synthesize cell-free RNA for a prolonged period at 29 degree C in a medium containing 100 mM KCl and 5 mM MgCl2. Actinomycin D inhibited 92 per cent of RNA synthesis, whereas approximately 60 per cent of RNA synthesis was sensitive to alpha-amanitin. When nuclei were incubated at 29 degrees C for 1 h, about 27 per cent of the newly synthesized RNA was released into the medium outside the nucleus. Analysis of this released material by affinity chromatography on an oligo(dT)-cellulose column revealed that 2.4 per cent of the total released RNA was adsorbed at high salt concentration. Most of this fraction was eluted with a low-salt buffer at 45 degrees C and the remainder by 50 per cent formamide, conditions that are necessary for elution of poly(A)-containing mRNP particles from oligo(dT)-cellulose. These results show that placental nuclei incubated in vitro synthesize poly(A)-containing RNA, which is released as a protein-bound complex. This procedure allows exploration of changes in mRNA release during placental development.

Control of RNA content of developing human placenta

Human placentae obtained early in pregnancy or at full term were examined for RNA content per cell, RNA polymerase types and activities, and chromatin template availability. The RNA:DNA ratio fell from 0.7 at 15 to 20 weeks to 0.4 at 40 weeks of pregnancy. Since RNase activities were similar at both times, the reduction in RNA content was attributed not to increased degradation, but to reduced synthesis. At both stages of pregnancy, about 55 to 60 per cent of the RNA polymerase activity in isolated placental nuclei was accounted for by RNA polymerase II, as judged by suppression of activity with alpha-amanitin and by separation of the extracted polymerases on DEAE-Sephadex. The relative roles of changes in polymerase activity and template availability were measured in nuclei from 20- and 40-week placentae. Nuclei showed 20 per cent greater polymerase activity in full-term than in early placentae, but the template availability of isolated chromatin for transcription by RNA polymerase II was 70 per cent less at full term. We conclude that the reduced amount of RNA per cell in the full-term placenta is due to reduced template availability that more than offsets the slight increase in polymerase activity.

Release of in vitro-synthesized poly(A)-containing RNA from isolated rat liver nuclei: characterization of the ribonucleoprotein particles involved

Nuclei isolated from rat liver were incubated under conditions in which RNA continued to be labeled with precursors for long periods. After 1 hr, during which the rate of RNA synthesis was constant, 25-30% of the newly synthesized RNA was recovered in the postnuclear supernatant. About 3-5% of this fraction was characterized as poly(A)-containing ribonucleoproteins by the following criteria: (i) characteristic elution profile in oligo(dT)-cellulose chromatography; (ii) size distribution of the molecules and their deproteinized RNAs; (iii) buoyant densities in CsCl gradients; (iv) presence of RNaseresistant fragments resembling poly(A)-protein complexes; and (v) identification of the protein components by sodium dodecyl sulfate/polyacrylamide gel electrophoresis. The sensitivity of labeling of the RNA synthesized and released from the nuclei to low doses of alpha-amanitin suggests the presence of polymerase II products in the particles. Comparison of the sizes of proteins in these particles with those of free and polysomal messenger ribonucleoproteins as well as with heterogenous nuclear ribonucleoproteins indicates that the released particles contain a protein of 78,000 daltons, which is also present in the other three classes of ribonucleoproteins, presumably at the 3'-poly(A) segments. In addition, a few other proteins, similar in size to those found in the cytoplasmic ribonucleoproteins, were also present in the released particles. It is suggested that proteins associated with heterogenous nuclear RNA are mostly exchanged before or at the time of release of mRNA from the nucleus; the remaining mRNA-associated proteins are added in the cytoplasm, possibly in relation to cytoskeleton attachment, followed by the removal of most of these proteins during polysome formation.

High turnover rate of transfer RNA in tumor tissue

Cancer patients and tumor-bearing animals excrete high levels of modified purines and pyrimidines some of which, e.g., N2,N2-dimethylguanosine, can originate only from transfer RNA (tRNA). Until recently, it could not be ascertained whether the high level of excretion of such compounds is due to cell death or specific tRNA turnover. However, an approach to this problem became feasible, with beta-aminoisobutyric acid as a probe. This compound is a terminal degradation product of thymine which is present in both DNA and tRNA. Since the pathway of synthesis of thymine is different in the two macromolecules, it and its end product, beta-aminoisobutyric acid can be differentially labeled with [14C]formate and [3H3]methylmethionine as precursors. Therefore the ratio of the two labels in the excreted beta-aminoisobutyric acid is a measure of the macromolecular origin of the degradation product. We have found from such analysis that tRNA's are not homogeneous in their turnover rate. There is a subpopulation that turns over much faster than the rest. The turnover rate of a subpopulation of tRNA's in tumor tissue exceeds the turnover rate of tRNA's in normal tissue. Such rapid degradation of tRNA's must be the source of the massive excretion of modified nucleosides by cancer patients which can be 10-fold higher than in normal subjects.

Mechanism of D-amphetamine inhibition of protein synthesis

At 1 h after intraperitoneal administration of D-amphetamine sulphate (15 mg/kg), rat brain polyribosomes show disaggregation accompanied by reduced capacity for in vitro peptide chain elongation. The direct action of amphetamine on cell-fine protein-synthesizing systems was therefore explored. When brain or liver polyribosomes from untreated rats were incubated with pH 5 enzyme, peptide chain elongation was not inhibited by the addition 4 mM amphetamine to the medium. On the other hand, an initiation-dependent system consisting of rat liver of brain mRNA and wheat germ S-30 fraction showed inhibition of [3H]leucine incorporation by 50% when 4 mM amphetamine were added. The metabolites of amphetamine, p-hydroxyamphetamine and p-hydroxynorephedrine, had no inhibitory action in either system, but the potent neurotoxin p-chloroamphetamine was a more powerful inhibitor of initiation than amphetamine. By using [3H]amphetamine, it was shown that amphetamine binds to the 80-S ribosomes of the wheat germ system. This binding depended on the presence in the system of natural liver or brain mRNA or several synthetic mRNAs, but was not promoted by polyuridylic acid as the messenger. Significantly, polyuridylic acid-dependent polyphenylalanine synthesis by the wheat germ system was not inhibited by amphetamine or p-chloroamphetamine. Therefore, it was concluded that amphetamine inhibits protein synthesis by interfering with initiation through a step related to formation of the mRNA ribosome complex.

Status of tRNA charging, trinucleotide acceptor sequence and tRNA nucleotidyltransferase activity in the human placenta

Samples of tRNA isolated from the cell sap of full-term human placenta were found to have a low capacity for accepting amino acids in the presence of partially purified synthetase preparations made from placental or rat liver cell sap. Gel electrophoresis of placental tRNA showed that part of this could be accounted for by gross degradation. The proportion of chargeable tRNA carrying amino acids was estimated by periodate oxidation followed by stripping and then charging with labeled amino acids. Only 50% of chargeable placental tRNA was in the charged state when isolated, whereas 87% of freshly isolated rat liver tRNA was found to be charged with amino acids. A fraction from placental cell sap was shown to have tRNA nucleotidyltransferase activity. When placental tRNA was incubated with this fraction and [3H]ATP or [3H]CTP, ATP was incorporated into about 12% of the tRNA molecules and CTP into 5-7%. When rat liver tRNA was used in place of placental tRNA, [3H]ATP was incorporated into less than 5% of the tRNA molecules. By using snake-venom diesterase over short periods of incubation, it was confirmed that the ATP had been incorporated terminally as AMP into the placental tRNA. These observations show that, in contrast to rat liver tRNA, tRNA prepared from human placenta is poorly charged with amino acids, many of the molecules lack the acceptor trinucleotide and there is extensive degradation beyond this stage.

Synthesis of human placental lactogen and human chorionic gonadotropin by polyribosomes and messenger RNA's from early and full term placentas

Synthesis of human placental lactogen (hPL) and of human chorionic gonadotropin (hCG) by membrane-bound and free polyribosomes from early and from full term human placentas was investigated by in vitro release of the nascent hormone peptides, followed by immunoprecipitation and electrophoresis in sodium dodecyl sulfate gels, and by specific binding of 125I-labeled hPL antibody to nascent peptide chains. In addition, messenger RNA'S Were extracted from total, free, and membrane-bound placental polyribosomes and their capacities for hPL and hCG synthesis were measured in a heterologous cell-free system prepared from wheat germ. Membrane-bound polyribosomes from full term placentas were several times more active in the synthesis of both peptide hormones than were free polyribosomes. By binding 125I-labeled hPL antibody to nascent chains on the polyribosomes, it was determined that hPL is made by clusters of seven to nine ribosomes. About 8% of the nascent peptide chains released by incubation of polyribosomes from full term placentas was accounted for by hPL, and 2% by hCG. In contrast, no chains of hPL were released by polyribosomes from 10-week placentas, whereas 11% of the total released chains were accounted for by hCG. When messenger RNAs prepared from the polyribosomes of 20- and 40-week placentas were used to stimulate protein synthesis in a wheat germ system, hPL accounted for 0.4 and 2%, respectively, of total protein synthesis, while hCG was 8 and 2%, respectively. This confirmed the relative proportions observed for nascent chains on the polyribosomes of early and late placentas. Unexpectedly, translation of mRNA from free polyribosomes yielded as much hPL and two-thirds as much hCG as did translation of mRNA from bound polyribosomes. We conclude, that the decreased blood levels of hCG and increased blood levels of hPL with advancing gestational age reflect the relative in vitro rates of synthesis of these hormones by placental polyribosomes, the abundance of which is determined by availability of their respective messenger RNAs at different times in gestation.

Novel mechanism for translational control in regulation of ferritin synthesis by iron

Poly(A)-containing RNA was isolated from the polyribosomal and post-ribosomal fractions of the livers of normal and iron-treated rats. These RNA fractions were then translated in a wheat germ system to provide a measure of the amount of ferritin mRNA present in each fraction. Following iron administration, there was a 2-fold increase in the amount of ferritin mRNA in the polyribosomal fraction. This increase was not inhibited by prior treatment of the rats with actinomycin D or cordycepin, suggesting a cytoplasmic control mechanism. In normal rats, the post-ribosomal fraction contained an amount of ferritin mRNA equal to that in the polyribosomes. When iron was administered, this untranslated ferritin mRNA became reduced to negligible quantities, thus accounting for the doubling of the ferritin mRNA content of the polyribosomal fraction. A scheme is proposed in which translation of the ferritin mRNA in the post-ribosomal fraction is prevented by adhering ferritin subunits. Iron administration removes this inhibition of the translation of ferritin mRNA by promoting aggregation of these subunits into ferritin.