The interleukin-3 receptor alpha chain is a unique marker for human acute myelogenous leukemia stem cells

Recent studies suggest that the population of malignant cells found in human acute myelogenous leukemia (AML) arises from a rare population of leukemic stem cells (LSCs). LSCs have been documented for nearly all AML subtypes and have been phenotypically described as CD34+/CD38- or CD34+/HLA-DR-. Given the potentially critical role of these primitive cells in perpetuating leukemic disease, we sought to further investigate their molecular and cellular characteristics. Flow cytometric studies using primary AML tissue showed that the interleukin-3 receptor alpha chain (IL-3Ralpha or CD123) was strongly expressed in CD34+/CD38- cells (98 +/- 2% positive) from 16 of 18 primary specimens. Conversely, normal bone marrow derived CD34+/CD38- cells showed virtually no detectable expression of the CD123 antigen. To assess the functional role of IL-3Ralpha positive cells, purified CD34+/CD123+ leukemia cells were transplanted into immune deficient NOD/SCID mice. These experiments showed that CD123+ cells were competent to establish and maintain leukemic populations in vivo. To begin to elucidate a biological role for CD123 in leukemia, primary AML samples were analyzed with respect to signal transduction activity in the MAPK, Akt, and Stat5 pathways. Phosphorylation was not detected in response to IL-3 stimulation, thereby suggesting CD123 is not active in conventional IL-3-mediated signaling. Collectively, these data indicate that CD123 represents a unique marker for primitive leukemic stem cells. Given the strong expression of this receptor on LSCs, we propose that targeting of CD123 may be a promising strategy for the preferential ablation of AML cells.

Multiple atherosclerotic plaque rupture in acute coronary syndrome: a three-vessel intravascular ultrasound study

BACKGROUND

To test the hypothesis of general atherosclerotic plaque destabilization during acute coronary syndrome (ACS), the present study sought to analyze the 3 coronary arteries by systematic intravascular ultrasound scan (IVUS).

METHODS AND RESULTS

Seventy-two arteries were explored in 24 patients referred for percutaneous coronary intervention after a first ACS with troponin I elevation. Fifty plaque ruptures (mean, 2.08 per patient; range, 0 to 6) were diagnosed by the association of a ruptured capsule with intraplaque cavity. Plaque rupture on the culprit lesion was found in 9 patients (37.5%). At least 1 plaque rupture was found somewhere other than on the culprit lesion in 19 patients (79%). These lesions were in a different artery than the culprit artery in 70.8% and were in both other arteries in 12.5% of these 24 patients. Complete IVUS examination of all 3 coronary axes in patients who had experienced a first ACS revealed that multiple atherosclerotic plaque ruptures were detected by IVUS; these multiple ruptures were present simultaneously with the culprit lesion; they were frequent and located (in three quarters of cases) on the 3 principal coronary trunks; and the multiple plaque ruptures in locations other than on the culprit lesion were less severe, nonstenosing, and less calcified.

CONCLUSION

Although one single lesion is clinically active at the time of ACS, the syndrome seems nevertheless associated with overall coronary instability.

The actin cytoskeleton response to oxidants: from small heat shock protein phosphorylation to changes in the redox state of actin itself

Actin is the major constituent of the cytoskeleton of almost all the eukaryotic cells. In vitro experiments have indicated that oxidant-stressed nonmuscle mammalian cells undergo remarkable changes in their morphology and in the structure of the actin cytoskeleton, often resulting in plasma membrane blebbing. Although the microfilament network is one of the earliest targets of oxidative stress, the mechanism by which oxidants change both the structure and the spatial organization of actin filaments is still a matter of debate and far from being fully elucidated. Starting from the 2-fold role of oxidants as injurious by-products of cellular metabolism and essential participants in cell signaling and regulation, this review attempts to gather the most relevant information related to (i) the activation of mitogen-activated protein (MAP) kinase stress-activated protein kinase-2/p38 (SAPK2/p38) which, via MAP kinase-activated protein (MAPKAP) kinase 2/3, leads to the phosphorylation of the actin polymerization (F-actin) modulator 25/27 kDa heat shock protein (HSP25/27), whose phosphorylation is causally related to the regulation of microfilament dynamics following oxidative stress; (ii) the alteration of the redox state of actin or some actin regulatory proteins. The actin cytoskeleton response to oxidants is discussed on the basis of the growing body of evidence indicating the actin system as the most sensitive constituent of the cytoskeleton to the oxidant attack.

Mutations in the gene encoding immunoglobulin mu-binding protein 2 cause spinal muscular atrophy with respiratory distress type 1

Classic spinal muscular atrophy (SMA) is caused by mutations in the telomeric copy of SMN1. Its product is involved in various cellular processes, including cytoplasmic assembly of spliceosomal small nuclear ribonucleoproteins, pre-mRNA processing and activation of transcription. Spinal muscular atrophy with respiratory distress (SMARD) is clinically and genetically distinct from SMA. Here we demonstrate that SMARD type 1 (SMARD1) results from mutations in the gene encoding immunoglobulin micro-binding protein 2 (IGHMBP2; on chromosome 11q13.2-q13.4). In six SMARD1 families, we detected three recessive missense mutations (exons 5, 11 and 12), two nonsense mutations (exons 2 and 5), one frameshift deletion (exon 5) and one splice donor-site mutation (intron 13). Mutations in mouse Ighmbp2 (ref. 14) have been shown to be responsible for spinal muscular atrophy in the neuromuscular degeneration (nmd) mouse, whose phenotype resembles the SMARD1 phenotype. Like the SMN1 product, IGHMBP2 colocalizes with the RNA-processing machinery in both the cytoplasm and the nucleus. Our results show that IGHMBP2 is the second gene found to be defective in spinal muscular atrophy, and indicate that IGHMBP2 and SMN share common functions important for motor neuron maintenance and integrity in mammals.

S-glutathionylation: from redox regulation of protein functions to human diseases

Reactive oxygen species (ROS) and reactive nitrogen species (RNS) play an integral role in the modulation of several physiological functions but can also be potentially destructive if produced in excessive amounts. Protein cysteinyl thiols appear especially sensitive to ROS/RNS attack. Experimental evidence started to accumulate recently, documenting that S-glutathionylation occurs in a number of physiologically relevant situations, where it can produce discrete modulatory effects on protein function. The increasing evidence of functional changes resulting from this modification, and the growing number of proteins shown to be S-glutathionylated both in vitro and in vivo support this contention, and confirm this as an attractive area of research. S-glutathionylated proteins are now actively investigated with reference to problems of biological interest and as possible biomarkers of human diseases associated with oxidative/nitrosative stress.

Double labelling of subcellular structures with organelle-targeted GFP mutants in vivo

BACKGROUND

The green fluorescent protein (GFP) of Aequorea victoria is emerging as a unique tool for monitoring complex phenomena such as gene expression and organelle structure and dynamics in living cells. The recent description of GFP mutants with modified spectral properties opens numerous new applications in cell biology. However, the expression and the characteristics of these GFP mutants in living eukaryotic cells have not been verified yet.

RESULTS

Here, we demonstrate the usefulness of the GFP mutants for cell biology studies in vivo, by the use of wild-type GFP, a 'bright' GFP mutant (S65T) and a mutant with blue-shifted excitation and emission spectra (Y66H/Y145F). We have constructed two GFP chimeras targeted to mitochondria, mtGFP(S65T) and mtGFP(Y66H/Y145F), with the same strategy used previously for mtGFP. In addition, two GFP chimeras targeted to the nucleus, nuGFP and nuGFP(S65T), were constructed by fusing the wild-type GFP or the (S65T) mutant to the rat glucocorticoid receptor. By co-transfecting mtGFP(Y66H/Y145F) and nuGFP, the nucleus and the mitochondria were visualized simultaneously in living cells. Similarly, mtGFP and mtGFP(Y66H/Y145F) were transfected into different populations of cells, and the events of cellular fusion, and mitochondrial intermixing and/or fusion, were directly monitored.

CONCLUSIONS

The successful expression of organelle-targeted GFP mutants in live eukaryotes expands the uses of this fluorescent protein in cell biology, allowing direct access to key biological issues, such as the study of the interactions of different organelles in vivo. These results also open the way to other exciting applications, such as the direct study of protein redistribution and protein-protein interactions in living cells.

Antithrombin III (ATIII) replacement therapy in patients with sepsis and/or postsurgical complications: a controlled double-blind, randomized, multicenter study

BACKGROUND

ATIII is decreased in sepsis and/or shock and its baseline value correlates with mortality. The efficacy of ATIII therapy on mortality was assessed in a selected group of patients admitted to the intensive care unit (ICU) in a double-blind, randomized, multicenter study.

METHODS

120 patients admitted to the ICU with an ATIII concentration < 70% were randomized to receive ATIII (total dose 24000 units) or placebo treatment for 5 days; 56 patients had septic shock.

RESULTS

ATIII concentrations in the treated group remained constant throughout the treatment period (range 97-102%). The Kaplan-Meier analysis showed no difference in overall survival between the two groups: 50 and 46% for ATIII and placebo, respectively. Septic shock and hemodynamic support were unbalanced in the two groups at admission. Therefore the Cox analysis was carried out after adjusting for these two variables. Treatment with ATIII decreases the risk of death with an odds ratio (OR) of 0.56. Of the covariates analyzed, septic shock and the baseline multiple organ failure score were negatively associated with survival and plasma activity level was positively associated with survival with an OR of 0.97 for each 1% increase in the ATIII plasma concentration at baseline.

CONCLUSIONS

The results of ATIII treatment in this population of patients suggests that replacement therapy reduces mortality in the subgroup of septic shock patients only.

An evaluation of the antioxidant and antiviral action of extracts of rosemary and Provençal herbs

Extracts of herbs and spices are increasingly of interest in the food industry because they retard oxidative degradation of lipids. There is also increasing interest in the antiviral activity of plant products. A liquid, deodorized rosemary extract and an oily extract of a mixture of Provençal herbs were tested for antioxidant and antiviral action in vitro. The rosemary extract (Herbor 025) and the extract of Provençal herbs (Spice Cocktail) inhibited peroxidation of phospholipid liposomes with 50% inhibition concentration values of 0.0009% (v/v) and 0.0035% (v/v), respectively. Herbor 025 and the spice cocktail (at 0.2%, v/v) reacted with trichloromethylperoxyl radical with calculated rates of 2.7 x 10(4) s-1 and 1.5 x 10(3) s-1, respectively. The main active components in the herbal preparations, carnosol and carnosic acid, at 0.05% (v/v) react with rate constants of (1-3) x 10(6) M-1 sec-1 and 2.7 x 10(7) M-1 sec-1, respectively. Both extracts show good antioxidant activity in the Rancimat test, especially in lard. Herbor 025 and the spice cocktail inhibited human immunodeficiency virus (HIV) infection at very low concentrations which were also cytotoxic. However, purified carnosol exhibited definite anti-HIV activity at a concentration (8 microM) which was not cytotoxic. Both preparations promoted some DNA damage in the copper-phenanthroline and the bleomycin-iron systems. The two herbal preparations possess antioxidant properties that may make them useful in the food matrix.

Orthologous myosin isoforms and scaling of shortening velocity with body size in mouse, rat, rabbit and human muscles

Maximum shortening velocity (V(0)) was determined in single fibres dissected from hind limb skeletal muscles of rabbit and mouse and classified according to their myosin heavy chain (MHC) isoform composition. The values for rabbit and mouse V(0) were compared with the values previously obtained in man and rat under identical experimental conditions. Significant differences in V(0) were found between fibres containing corresponding myosin isoforms in different species: as a general rule for each isoform V(0) decreased with body mass. Myosin isoform distributions of soleus and tibialis anterior were analysed in mouse, rat, rabbit and man: the proportion of slow myosin generally increased with increasing body size. The diversity between V(0) of corresponding myosin isoforms and the different myosin isoform composition of corresponding muscles determine the scaling of shortening velocity of whole muscles with body size, which is essential for optimisation of locomotion. The speed of actin translocation (V(f)) in in vitro motility assay was determined with myosins extracted from single muscle fibres of all four species: significant differences were found between myosin isoforms in each species and between corresponding myosin isoforms in different species. The values of V(0) and V(f) determined for each myosin isoform were significantly correlated, strongly supporting the view that the myosin isoform expressed is the major determinant of maximum shortening velocity in muscle fibres.

DNA ligase I is recruited to sites of DNA replication by an interaction with proliferating cell nuclear antigen: identification of a common targeting mechanism for the assembly of replication factories

In mammalian cells, DNA replication occurs at discrete nuclear sites termed replication factories. Here we demonstrate that DNA ligase I and the large subunit of replication factor C (RF-C p140) have a homologous sequence of approximately 20 amino acids at their N-termini that functions as a replication factory targeting sequence (RFTS). This motif consists of two boxes: box 1 contains the sequence IxxFF whereas box 2 is rich in positively charged residues. N-terminal fragments of DNA ligase I and the RF-C large subunit that contain the RFTS both interact with proliferating cell nuclear antigen (PCNA) in vitro. Moreover, the RFTS of DNA ligase I and of the RF-C large subunit is necessary and sufficient for the interaction with PCNA. Both subnuclear targeting and PCNA binding by the DNA ligase I RFTS are abolished by replacement of the adjacent phenylalanine residues within box 1. Since sequences similar to the RFTS/PCNA-binding motif have been identified in other DNA replication enzymes and in p21(CIP1/WAF1), we propose that, in addition to functioning as a DNA polymerase processivity factor, PCNA plays a central role in the recruitment and stable association of DNA replication proteins at replication factories.

Reversible S-glutathionylation of Cys 374 regulates actin filament formation by inducing structural changes in the actin molecule

S-glutathionylation, the reversible formation of mixed disulphides of cysteinyl residues in target proteins with glutathione, occurs under conditions of oxidative stress; this could be a posttranslational mechanism through which protein function is regulated by the cellular redox status. A novel physiological relevance of actin polymerization regulated by glutathionylation of Cys(374) has been recently suggested. In the present study we showed that glutathionylated actin (GS-actin) has a decreased capacity to polymerize compared to native actin, filament elongation being the polymerization step actually inhibited. Actin polymerizability recovers completely after dethiolation, indicating that S-glutathionylation does not induce any protein denaturation and is therefore a reversible oxidative modification. The increased exposure of hydrophobic regions of protein surface observed upon S-glutathionylation indicates changes in actin conformation. Structural alterations are confirmed by the increased rate of ATP exchange as well as by the decreased susceptibility to proteolysis of the subtilisin cleavage site between Met(47) and Gly(48), in the DNase-I-binding loop of the actin subdomain 2. Structural changes in the surface loop 39-51 induced by S-glutathionylation could influence actin polymerization in view of the involvement of the N-terminal portion of this loop in intermonomer interactions, as predicted by the atomic models of F-actin.

Actin carbonylation: from a simple marker of protein oxidation to relevant signs of severe functional impairment

The number of protein-bound carbonyl groups is an established marker of protein oxidation. Recent evidence indicates a significant increase in actin carbonyl content in both Alzheimer's disease brains and ischemic hearts. The enhancement of actin carbonylation, causing the disruption of the actin cytoskeleton and the loss of the barrier function, has also been found in human colonic cells after exposure to hypochlorous acid (HOCl). Here, the effects of oxidation induced by HOCl on purified actin are presented. Results show that HOCl causes a rapidly increasing yield of carbonyl groups. However, when carbonylation becomes evident, some Cys and Met residues have been already oxidized. Covalent intermolecular cross-linking as well as some noncovalent aggregation of carbonylated actin have been found. The covalent cross-linking, unaffected by reducing and denaturing agents, parallels an increase in dityrosine fluorescence. Moreover, HOCl-mediated oxidation induces the progressive disruption of actin filaments and the inhibition of F-actin formation. The molar ratios of HOCl to actin that lead to inhibition of actin polymerization seem to have effect only on cysteines and methionines. The process that involves oxidation of amino acid side chains with formation of a carbonyl group would occur at an extent of oxidative insult higher than that causing the oxidation of some critical amino acid residues. Therefore, the increase in actin content of carbonyl groups found in vivo would indicate drastic oxidative modification leading to drastic functional impairments.

Specific contributions of various muscle fibre types to human muscle performance: an in vitro study

Human skeletal muscle fibres can be divided in five groups: 1, 1-2A, 2A, 2A-2B and 2B, by using myosin heavy chain (MHC) isoforms as molecular markers. This study aimed to define the contribution of each fibre type to the contractile performance of human muscles. Single fibre segments were dissected from bioptic samples of vastus lateralis and chemically skinned. Force-velocity properties, including isometric tension (P0), maximal shortening velocity (Vmax), maximum power output (Wmax) and the velocity at which Wmax is reached (Vopt), were determined at maximum calcium activation. Among these parameters Wmax showed the largest range of variation: about nine times between 2B and slow fibres. Vopt also showed large (about four times) and significant variations between fibre types. Force development at submaximum calcium activation was studied and force-pCa curves were obtained for each fibre type. Calcium sensitivity was greater in 2B than in 2A and in slow fibres. The slope of the force-pCa curve was greater in fast than in slow fibres. At the end of the experiment the MHC isoform composition of each fibre segment was determined by gel electrophoresis. The functional properties of each fibre type are discussed in the light of the motor unit recruitment mechanism to understand their possible physiological role.

The simplified papilla preservation flap in the regenerative treatment of deep intrabony defects: clinical outcomes and postoperative morbidity

BACKGROUND

The aims of the present multi-center, randomized, controlled clinical trial were: 1) to compare the efficacy of the simplified papilla preservation flap with and without a barrier membrane in deep intrabony defects; 2) to evaluate the postoperative morbidity and surgical complications; and 3) to preliminarily test the impact of baseline tooth mobility on clinical outcomes.

METHODS

This parallel group, randomized, multi-center, controlled clinical trial involved 112 patients in 8 periodontal practices in 4 countries. A deep intrabony defect in each patient was accessed with the simplified papilla preservation flap. In the test defects, a bioabsorbable membrane was positioned. Patients' experiences with the surgical procedure and postoperative period were evaluated with a questionnaire. Clinical outcomes included clinical attachment level (CAL) and probing depth (PD) changes.

RESULTS

Complete observations were available for 55 test and 54 control defects. CAL gains at 1 year were 3.5 +/- 2.1 mm in the guided tissue regeneration (GTR) group and 2.6 +/- 1.8 mm in the control group (P = 0.0117). CAL gains > or = 4 mm were observed in 50.9% of GTR sites and 33.3% of control sites. A significant center effect of 2.1 mm was observed (P= 0.01). Initial PD (P= 0.01) and baseline tooth mobility (P= 0.036) were significant covariates. During the procedure, 30.4% of test and 28.6% of controls reported feeling moderate pain, and subjects estimated the hardship of the procedure at 24 +/- 25 visual analog scale (VAS) units in the test group, and at 22 +/- 23 VAS in controls. In terms of the investigated outcomes, differences between test and control groups were not statistically significant. Among the postoperative complications, edema was most prevalent at week 1, and more frequently associated with the test treatment (P= 0.01). In the test group, 53.6% of membranes were exposed at week 3.

CONCLUSIONS

The present study further supports the added benefits of guided tissue regeneration with respect to access flap alone in the treatment of deep intrabony defects, as well as the general efficacy of GTR in different clinical settings. Furthermore, our study indicates a possible influence of baseline tooth mobility on clinical outcomes.

Methionine oxidation as a major cause of the functional impairment of oxidized actin

A significant specific increase in the actin carbonyl content has been recently demonstrated in human brain regions severely affected by the Alzheimer's disease pathology, in postischemic isolated rat hearts, and in human intestinal cell monolayers following incubation with hypochlorous acid (HOCl). We have very recently shown that exposure of actin to HOCl results in the immediate loss of Cys-374 thiol, oxidation of some methionine residues, and, at higher molar ratios of oxidant to protein, increase in protein carbonyl groups, associated with filament disruption and inhibition of filament formation. In the present work, we have studied the effect of methionine oxidation induced by chloramine-T (CT), which at neutral or slightly alkaline pH oxidizes preferentially Met and Cys residues, on actin filament formation and stability utilizing actin blocked at Cys-374. Methionines at positions 44, 47, and 355, which are the most solvent-exposed methionyl residues in the actin molecule, were found to be the most susceptible to oxidation to the sulfoxide derivative. Met-176, Met-190, Met-227, and Met-269 are the other sites of the oxidative modification. The increase in fluorescence associated with the binding of 8-anilino-1-naphtalene sulfonic acid to hydrophobic regions of the protein reveals that actin surface hydrophobicity increases with oxidation, indicating changes in protein conformation. Structural alterations were confirmed by the decreased susceptibility to proteolysis and by urea denaturation curves. Oxidation of some critical methionines (those at positions 176, 190, and 269) causes a complete inhibition of actin polymerization and severely affects the stability of actin filaments, which rapidly depolymerize. The present results would indicate that the oxidation of some critical methionines disrupts specific noncovalent interactions that normally stabilize the structure of actin filaments. We suggest that the process involving formation of actin carbonyl derivatives would occur at an extent of oxidative insult higher than that causing the oxidation of some critical methionine residues. Therefore, methionine oxidation could be a damaging event preceding the appearance of carbonyl groups on actin and a major cause for the functional impairment of the carbonylated protein recently observed both in vivo and in vitro.

Preferential transport of glutathione versus glutathione disulfide in rat liver microsomal vesicles

A bi-directional, saturable transport of glutathione (GSH) was found in rat liver microsomal vesicles. GSH transport could be inhibited by the anion transport blockers flufenamic acid and 4, 4'-diisothiocyanostilbene-2,2'-disulfonic acid. A part of GSH taken up by the vesicles was metabolized to glutathione disulfide (GSSG) in the lumen. Microsomal membrane was virtually nonpermeable toward GSSG; accordingly, GSSG generated in the microsomal lumen could hardly exit. Therefore, GSH transport, contrary to previous assumptions, is preferred in the endoplasmic reticulum, and GSSG entrapped and accumulated in the lumen creates the oxidized state of its redox buffer.

Neonatal screening for hearing disorders in infants at risk: incidence, risk factors, and follow-up

OBJECTIVE

To determine the incidence and risk factors for hearing disorders in a selected group of neonates and the feasibility of selective hearing screening.

SETTINGS

Multicenter prospective trial at five centers in Germany.

METHODS

Enrollment criteria: in addition to previously defined risk factors by the Joint Committee on Infant Hearing (family history of hearing loss, in utero infections, craniofacial anomalies, birth weight <1500 g, critical hyperbilirubinemia, ototoxic medications, bacterial meningitis, postnatal asphyxia, mechanical ventilation >5 days, stigmata, or syndromes associated with hearing loss), the impact of maternal drug abuse, birth weight <10th percentile, persistent pulmonary hypertension, and intracranial hemorrhage more than or equal to grade III or periventricular leukomalacia on infant hearing were evaluated. The screening procedure was performed by automated auditory brainstem response (A-ABR; ALGO 1-plus; Natus Med Inc, San Carlos, CA).

STATISTICS

univariate analyses of risk factors versus A-ABR results and a multivariate regression analysis were used; additionally, the total test time was recorded.

RESULTS

Seven hundred seventy recordings from 777 infants enrolled consecutively constitute the basis of this analysis. Mean gestational age was 33.8 +/- 4.3 weeks, birth weight 2141 +/- 968 g; 431 infants being male and 339 female; 41 (5.3%) infants exhibited pathologic A-ABR results (16 bilateral and 25 unilateral). Meningitis or sepsis, craniofacial malformations, and familial hearing loss were independent significant risk factors. Median total test time was 25 minutes. Follow-up examinations in 31 infants revealed persistent hearing loss in 18 infants (13 infants sensorineural, 5 from mixed disorders), 7 requiring amplification.

CONCLUSION

Hearing screening in high-risk neonates revealed a total of 5% of infants with pathologic A-ABR (bilateral 2%). Significant risk factors were familial hearing loss, bacterial infections, and craniofacial abnormalities. Other perinatal complications did not significantly influence screening results indicating improved perinatal handling in a neonatal population at risk for hearing disorders.

Unilateral nephrectomy and cisplatin as risk factors of ifosfamide-induced nephrotoxicity: analysis of 120 patients

PURPOSE

This study was performed to identify risk factors of ifosfamide-induced renal damage.

PATIENTS AND METHODS

Renal function was assessed in 120 patients at a minimum of 3 months after completion of chemotherapy including ifosfamide. The cumulative ifosfamide dose ranged from 2 to 95 g/m2 (median, 30 g/m2). Ten patients had undergone unilateral nephrectomy; combination cytostatic treatment included cisplatin in 51 and methotrexate in 57. Sixty-eight patients had received gentamicin treatment. The glomerular filtration rate was estimated using the Schwartz formula. Proximal tubular function was assessed by the percent reabsorptions of glucose and 16 amino acids, the fractional excretion of sodium, and the fractional reabsorption of phosphate. In addition, the serum bicarbonate level was measured.

RESULTS

Proximal tubular dysfunction--with a predominance of renal amino acid (66.3%) and phosphate loss (38.3%)--was much more frequent than both glomerular impairment and acidosis. Seven patients were identified as having renal Fanconi's syndrome, and generalized tubulopathy was noted in another 15 patients. Ifosfamide-induced nephrotoxicity was dose-dependent, with a weak linear inverse correlation between cumulative ifosfamide dose and fractional phosphate reabsorption. Unilateral nephrectomy proved to be the single most important risk factor (odds ratio for the development of renal Fanconi's syndrome, 11.4), but cisplatin also significantly enhanced ifosfamide-mediated nephrotoxicity. Methotrexate, gentamicin, and patient age at primary diagnosis had no influence on renal function.

CONCLUSION

Ifosfamide chemotherapy should probably be restricted in patients after unilateral nephrectomy.

Piggy-back versus conventional technique in liver transplantation: report of a randomized trial

Liver transplantation with preservation of the recipient vena cava (the "piggy-back" technique) has been proposed as an alternative to the traditional method. We performed a randomized study on 39 cirrhotic patients, 20 who underwent the piggy-back technique (group 1) and 19 the traditional method using venovenous bypass (group 2) to evaluate the feasibility and true advantages of the piggy-back technique compared to the traditional method. Two patients were switched to the conventional technique due to the presence of a caudate lobe embracing the vena cava in one patient and a caval lesion in the other. Statistically significant differences between the two groups were only found for the warm ischemia time (48.5 +/- 13 min for piggy-back vs 60 +/- 12 min for the conventional method) and for renal failure (zero cases in group 1 vs four cases in group 2). We therefore believe that liver transplantation with the piggy-back technique can easily be performed in almost all cases, and that only a few, specific situations, such as a very enlarged caudate lobe, do not justify its routine use.

Role of protein -SH groups in redox homeostasis--the erythrocyte as a model system

The reactivities of the sulfhydryl groups of rat, turkey, human, and calf hemoglobin were studied together with the enzyme activities of glutathione peroxidase, glutathione reductase, glucose-6-phosphate dehydrogenase, and glutaredoxin in lysed erythrocytes to evaluate their roles in regulating redox homeostasis. The results of -SH reactivity showed rate constants spanning four orders of magnitude (k2, calf, 6.67 M-1 s-1; rat -SH fast reacting, 2.8 x 10(4) M-1 s-1). Enzyme activities of glucose-6-phosphate dehydrogenase ranged from 0.402 U/ml (calf) to 0.900 U/ml (rat), glutathione reductase from 0. 162 U/ml (rat) to 0.381 U/ml (human), glutaredoxin from 0.778 U/ml (rat) to 2.28 U/ml (turkey), and glutathione peroxidase from 2.07 U/ml (human) to 27.3 U/ml (rat). Blood samples of the four species were also treated with 0.5-1.5 mM tert-butyl hydroperoxide (t-BOOH) or diamide, and levels of glutathione-derived species [GSH, GSSG, and glutathione-protein mixed disulfides (GS-SP)] were determined within 120 min and related to the corresponding protein -SH group (PSH) reactivities and enzyme repertoires. In all cases t-BOOH rapidly transformed GSH into GSSG by the action of glutathione peroxidase; GSSG was in turn transformed into GS-SP, according to the reaction GSSG + PSH --> GS-SP + GSH, or reduced back to GSH by glutathione reductase. The GSSG reduction was more efficient in rat and human blood, due to the contribution of the fast-reacting -SH of hemoglobin, in the rat, and to the efficiency of the enzyme repertoire of human blood. Calf blood showed a relatively low capacity to restore normal values after oxidative stress, due to its low PSH reactivity and the weak contribution of its enzymes. Diamide treatment, which is known to react nonenzymatically with thiols, gave increased GS-SP levels in rat and turkey, but not in human and calf blood, as expected from the different corresponding PSH reactivities. Species with relatively high PSH reactivity and glucose 6-phosphate dehydrogenase activity, such as the rat, therefore had a higher antioxidant capacity than species (calf) in which these parameters were relatively low.

Anthracycline-based chemotherapy as primary treatment for intravascular lymphoma

BACKGROUND

Optimal therapeutic management of intravascular lymphoma (IVL) lacks precise guidelines.

PATIENTS AND METHODS

The clinico-pathological features of 38 HIV-negative patients with IVL were reviewed to define efficacy of chemotherapy in these malignancies. Clinical characteristics of 22 patients treated with chemotherapy and of 16 untreated patients were compared in order to understand better the impact and causes of potential patient selection.

RESULTS

Median age was 70 years (range 34-90), with a male/female ratio of 0.9; 23 (61%) patients had Eastern Cooperative Oncology Group performance status (ECOG-PS) > 1; 21 (55%) had systemic symptoms. Cutaneous lesions and anemia were significantly more common among patients treated with chemotherapy; central nervous system (CNS) and renal involvement were significantly more common among untreated patients. Chemotherapy was associated with a response rate of 59% and a 3-year overall survival of 33 +/- 11%. Five of six patients with CNS involvement received chemotherapy: four of them died early; only one patient, treated with adriamycin, cyclophosphamide, vincristine, methotrexate, bleomycin and prednisolone (MACOP-B) followed by high-dose chemotherapy and autologous stem cell transplantation (ASCT), was alive at 19 months. High-dose chemotherapy supported by ASCT was indicated at diagnosis in another patient (43 years of age, stage I), who was alive at 71 months, and at relapse after cyclophosphamide, doxorubicin, vincristine and prednisone (CHOP) in two patients who died early after transplantation. PS < or = 1, disease limited to the skin, stage I, and use of chemotherapy were independently associated with better outcome.

CONCLUSIONS

Anthracycline-based chemotherapy is the standard treatment for IVL. However, survival is disappointing, with a relevant impact of diagnostic delay and lethal complications. More intensive combinations, containing drugs with higher CNS bioavailability, are needed in cases with brain involvement, and the role of high-dose chemotherapy supported by ASCT should be further investigated in younger patients with unfavorable features.

Oxygen radical-mediated reduction in basal and agonist-evoked NO release in isolated rat heart

Oxygen free radicals (OFR) play a primary role in ischemia-reperfusion-mediated vascular dysfunction and this is paralleled by a loss of endothelial nitric oxide synthase (eNOS) activity. The authors tested whether a direct exposure to OFR may affect vascular relaxation by altering nitric oxide (NO) release. Effects of electrolysis(EL)-generated OFR on basal and agonist-evoked NO release were monitored in isolated rat hearts by oxyhemoglobin assay. Electrolysis-induced changes were compared with those obtained after 30 min perfusion with NOS and cyclooxygenase (COX) inhibitors NG-nitro-L-arginine methyl ester (L-NAME, 100 microM) and indomethacin (INDO, 1 m M). Electrolysis-generated hydroxyl radical (.OH) formed by.O2-and H2O2 via the Fenton reaction as revealed by Electron Paramagnetic Resonance (EPR). After EL, basal NO release declined by 60% and coronary perfusion pressure (CPP) increased by approximately 70%. L-NAME/INDO perfusion similarly lowered NO release (-63%) but increased CPP less than EL (56+/-3%P<0.03 v post-EL). In presence of excess substrates and cofactors eNOS activity was not affected by EL. Both acetylcholine (ACh; 1 microM) and bradykinin (BK; 10 n M) had minimal effect in reversing EL-induced vasoconstriction, whereas both partially reversed L -NAME/INDO-mediated constriction. Sodium nitroprusside (SNP, 1 microM) completely reversed L-NAME/INDO constriction and partly countered that after EL (-38+/-2.5, P<0.001). Acetylcholine-evoked NO release was nearly abolished by both treatments whereas BK still elicited partial NO release after eNOS/cyclooxygenase inhibition (P<0.001) but not after EL. In conclusion, OFR severely impair NO-mediated coronary vasorelaxation affecting both basal and agonist-evoked NO release but not eNOS activity. However, EL also significantly blunts NOS/COX-independent vasodilation suggesting alteration of other vasodilatative pathways.

Left atrial size is the major predictor of cardiac death and overall clinical outcome in patients with dilated cardiomyopathy: a long-term follow-up study

HYPOTHESIS

This study was undertaken to determine whether echo-derived left atrial dimension and other echocardiographic, clinical, and hemodynamic parameters detected at the time of entry into the study may influence prognosis in patients with dilated cardiomyopathy during a long-term follow-up.

METHODS

This was a prospective cohort analysis of 123 patients with dilated cardiomyopathy. Clinical evaluation, chest x-ray, M-mode and two-dimensional echocardiogram, exercise test, 72-h ambulatory electrocardiogram monitoring, and cardiac catheterization study were performed in all patients. The study was divided into two phases: in the first phase, patients were divided into two groups according to the left atrial size (> or = 45 mm; < 45 mm), with cardiac death as the end point. In the second phase, all patients were further divided into two groups according to their clinical course. A multivariate analysis was performed to determine independent correlated parameters of cardiac mortality and overall clinical outcome.

RESULTS

Cardiac mortality rate was 47.9%: 29% in the group without left atrial dilation and 54.3% in the group with dilated left atrium. Multivariate analysis revealed that left atrium > or = 45 mm, New York Heart Association functional classes III/IV, and the presence of one or more episodes of ventricular tachycardia at Holter monitoring were independent predictors of cardiac mortality, while left atrium > or = 45 mm, left ventricular end-diastolic pressure > 17 mmHg, and exercise tolerance < or = 15 min were independent predictors of poor clinical outcome.

CONCLUSIONS

Our results revealed that left atrial size is the principal independent predictor of prognosis in patients with dilated cardiomyopathy in that patients with left atrial dilation had an increase in mortality and a worse clinical outcome compared with those without left atrial dilation.

Cysteinylation and homocysteinylation of plasma protein thiols during ageing of healthy human beings

The purpose of the present study was to determine the relative amount of S-thiolated proteins (i.e. S-homocysteinylated, S-cysteinylglycinylated, S-glutathionylated and S-cysteinylated proteins) to the total protein thiols (i.e. the sum of reduced protein sulphydryl groups (PSHs) and protein mixed disulphides with homocysteine [HcySH], cysteinylglycine, cysteine [CysSH] and glutathione) in the plasma of healthy individuals aged 20 to 93. After plasma separation, total protein thiols, S-thiolated proteins, as well as CysSH, cystine, HcySH and homocystine were measured by high-performance liquid chromatography (HPLC) with fluorescence determination of the thiol-monobromobimane conjugate. Determination of plasma levels of protein thiols was performed by spectrophotometry with 5,5′-dithiobis(2-nitrobenzoic acid) as a titrating agent. The present study demonstrates an age-dependent reduction in the amount of PSHs, and an age-dependent increase in cysteinylated and homocysteinylated plasma proteins in healthy human beings. This indicates that the efficiency of the reduced protein thiol pool as an antioxidant defence system decreases with age, possibly causing an increased risk of irreversible oxidation (i.e. further oxidation to sulphinic and sulphonic acids, which are usually not reducible by thiol reducing agents) of sulphydryl groups of plasma proteins. The drop in the plasma level of protein sulphydryl groups suggests depletion and/or impairment of the antioxidant capacity of plasma, likely related to an alteration of the delicate balance between the different redox forms of thiols.