Expression studies of superoxide dismutases in nodules and leaves of transgenic alfalfa reveal abundance of iron-containing isozymes, posttranslational regulation, and compensation of isozyme activities

The composition of antioxidant enzymes, especially superoxide dismutase (SOD), was studied in one nontransgenic and three transgenic lines of nodulated alfalfa plants. Transgenic lines overproduced MnSOD in the mitochondria of nodules and leaves (line 1-10), MnSOD in the chloroplasts (line 4-6), and FeSOD in the chloroplasts (line 10-7). In nodules of line 10-7, the absence of transgene-encoded FeSOD activity was due to a lack of mRNA, whereas in nodules of line 4-6 the absence of transgene-encoded MnSOD activity was due to enzyme inactivation or degradation. Transgenic alfalfa showed a novel compensatory effect in the activities of MnSOD (mitochondrial) and FeSOD (plastidic) in the leaves, which was not caused by changes in the mRNA levels. These findings imply that SOD activity in plant tissues and organelles is regulated, at least partially, at the posttranslational level. All four lines had low CuZnSOD activities and an abundant FeSOD isozyme, especially in nodules, indicating that FeSOD performs important antioxidant functions other than the scavenging of superoxide radicals generated in photosynthesis. This was confirmed by the detection of FeSOD cDNAs and proteins in nodules of other legumes such as cowpea, pea, and soybean. The cDNA encoding alfalfa nodule FeSOD was characterized and the deduced protein found to contain a plastid transit peptide. A comparison of sequences and other properties reveals that there are two types of FeSODs in nodules.

Persistence of secretory antiamoebic antibodies in patients with past invasive intestinal or hepatic amoebiasis

In the present work, it was demonstrated that in amoebic dysentery and amoebic liver abscess patients, the secretory response is long-lasting (> 12 months); and 50% of amoebic dysentery patients developed circulating antiamoebic IgG in comparison with 100% of amoebic liver abscess individuals. A total of 83% of these individuals developed high levels of serum anti-Entamoeba histolytica IgA. However, only 10.4% of the dysentery patients showed this anti-E. histolytica antibody isotype in serum. There was no correlation between secretory and serum antiamoebic response, suggesting independent inductive and effector sites in both compartments.

Rapid allergen delivery with photomechanical waves for inducing allergic skin reactions in the hairless guinea pig animal model

BACKGROUND

Patch testing is the confirmatory procedure for allergic contact dermatitis. The test requires the application of chemicals under occlusion for approximately 48 hours to maximize penetration, although it can also produce irritation. Photomechanical waves (PW) have been shown to render the stratum corneum transiently permeable and facilitate the delivery of macromolecules into the epidermis. This alternative might reduce prolonged occlusion of the skin to minimize irritancy, while retaining the sensitivity of the test.

OBJECTIVE

PW was used to facilitate the delivery of an allergen into the skin in vivo.

METHODS

The allergic skin reaction using PW delivery was compared with 5-minute and 21-hour occlusion in a sensitized hairless albino guinea pig model. The pigs were sensitized by intradermal injection of (0.01%) dinitrochlorobenzene (DNCB) and topical administration (0.1%, 1 week later) of the hapten. One month later, testing for the allergic response was performed by the administration with PW of 10 microL of 0.1% DNCB.

RESULTS

Our results show that there was an allergic reaction for the 24 hour occlusion or PW delivery of the antigen. In contrast, no response was observed for the 5-minute occlusion with the antigen.

CONCLUSION

The rapid delivery of antigens with PW can improve the test for the diagnosis of contact dermatitis.

Recovery from fatigue in fast and slow single intact skeletal muscle fibers from aging mouse

In the present work, we studied the recovery from fatigue (RF) of single intact fast- and slow-twitch muscle fibers from young (age 5--7 months) and old (age 22--24 months) mice. To examine whether differences in RF underlie decreases in muscle strength and endurance with aging, we performed in vitro experiments in manually dissected extensor digitorum longus (EDL) and soleus muscle fibers. We measured the recovery of the maximum force every 5 min for a total period of 30 min after inducing fiber fatigue. Fibers were classified, according to the fatigue index, into the following three groups: 0.75--0.99, 0.5--0.74, and <0.5. Although the tetanic tension of EDL and soleus fibers from young and old mice recovered significantly, no statistically significant difference in tension or recovery time was observed between age groups. These data support the concept that the reported decline in muscle force and endurance with aging is not related to changes in RF of individual muscles fibers.

Age-dependent fatigue in single intact fast- and slow fibers from mouse EDL and soleus skeletal muscles

In the present work, we investigate age-dependent changes in isometric endurance in response to repetitive stimulation in single intact fast- and slow-twitch muscle fibers from young and old mice. To examine this issue we performed in vitro experiments in manually dissected EDL and soleus muscle fibers. We examined the force generation capacity of fibers in response to two stimulation protocols characterized by different inter-tetanic intervals, named short (1-s) and long interval (3.65-s). Fatigability was measured according to the fatigue index (FI, ratio between the maximum tension recorded in the last over the first tetanus in a train of pulses), the time course of the FI and sag (gradual decrease in force during a partially fused tetanic contraction). Fibers were classified according to the FI using two different criteria previously used in the literature (first criterion: FI > or = 1, 075-099, 0.5-074 and < 0.5; second criterion: FI > or = 1, 0.75-0.99, 0.25-0.74 and < 0.25). The fatigue index distribution recorded in the population of fibers corresponding to EDL and soleus muscles from young and old mice studied with the short and long interval protocols was not statistically different. In summary, these results support the concept that the decline in mechanical performance with aging is not related with changes in fatigability of individual fast- or slow twitch muscles fibers.

Involvement of inducible isoforms of COX and NOS in streptozotocin-pancreatic damage in the rat: interactions between nitridergic and prostanoid pathway

Streptozotocin-induced pancreatic damage involves nitric oxide (NO) and prostaglandins (PGs) overproduction. In this work we aim to evaluate a putative relationship between the elevated NO levels and the altered prostanoid production in pancreatic tissue from streptozotocin-diabetic rats. Total NOS activity and nitrate/nitrite pancreatic levels in tissues from diabetic rats are decreased when the cyclooxygenase (COX) inhibitor indomethacin (INDO) is added to the incubating medium, while the addition of PGE(2)increases nitrate/nitrite production and NOS levels. INDO and PGE(2)selectively affect Ca(2+)-dependent NOS (iNOS) activity in diabetic tissues, and they have not been able to modify nitrate/nitrite levels, iNOS or Ca(2+)-dependent (cNOS) in control tissues. When the NOS inhibitor L-NMMA was present in the incubating medium, control pancreatic [(14)C]-Arachidonic Acid ([(14)C]-AA) conversion to 6-keto PGF(1 alpha)and to TXB(2)was lower, and PGF(2 alpha), PGE(2)and TXB(2)production from diabetic tissues diminished. The NO donors, spermine nonoate (SN) and SIN-1, enhanced TXB(2)levels in control tissues, while PGF(2 alpha), PGE(2)and TXB(2)levels from diabetic tissues were increased. PGE(2)production from control and diabetic tissues was assessed in the presence of the NO donor SN plus INDO or NS398, a specific PG synthase 2 inhibitor. When SN combined with INDO or NS398 was added, the increment of PGE(2)production was abolished by both inhibitors in equal amounts, indicating that the activating effect of nitric oxide is exerted on the inducible isoform of cyclooxygenase. In the diabetic rat, prostaglandins and NO seem to stimulate the generation of each other, suggesting a lack of regulatory mechanisms that control the levels of vasoactive substances in acute phase of beta-cell destruction.

Efficacy of low dose schedule pamidronate infusion in children with osteogenesis imperfecta

BACKGROUND

Osteogenesis imperfecta (OI) is a rare condition in which bones are abnormally brittle with frequent fractures. A variety of therapeutic agents has been used with low efficacy. In this study, we present three patients treated for 4 years with i.v. pamidronate.

PATIENTS AND METHODS

Three prepubertal patients, aged 9 (M), 9 (F) and 11 (F) years old, with OI, were treated with 30-60 mg i.v. pamidronate every 6 months over four years. Determinations were made of plasma 1,25-dihydroxycholecalciferol, 25-hydroxycholecalciferol, insulin-like growth factor-I (IGF-I) and its transport protein (IGFBP3), osteocalcin, total alkaline phosphatase and its osseous fraction, and parathormone (PTH) at baseline and after every pamidronate infusion, Densitometry and X-ray of the vertebral column were performed at the same intervals.

RESULTS

Significant reductions of number of bone fractures and pain were observed in all patients, despite lack of any modification in biochemical parameters. Lumbar X-ray and densitometry showed a striking improvement by the end of the treatment period.

CONCLUSION

Pamidronate seems to be useful in the treatment of patients with osteogenesis imperfecta.

HIV-1 Tat inhibits IL-2 gene transcription through qualitative and quantitative alterations of the cooperative Rel/AP1 complex bound to the CD28RE/AP1 composite element of the IL-2 promoter

Dysregulation of cytokine secretion plays an important role in AIDS pathogenesis. Here, we demonstrate that expression of HIV-1 Tat protein in Jurkat cells induces a severe impairment of IL-2 but not TNF gene transcription. Interestingly, this inhibition correlates with the effect of the viral protein on the transactivation of the CD28RE/AP1 composite element (-164/-154), but not with that observed on the NFAT/AP1 site of the IL-2 gene promoter, neither with the effect on NF-kappa B- nor AP1-independent binding sites. Endogenous expression of Tat induced a decrease in the amount of the specific protein complex bound to the CD28RE/AP1 probe after PMA plus calcium ionophore stimulation. This effect was accompanied by qualitative alterations of the AP1 complex. Thus, in wild-type Jurkat cells, c-jun was absent from the complex, whereas in Tat-expressing cells, c-jun was increasingly recruited overtime. By contrast, similar amounts of c-rel and a small amount of NFAT1 were detected both in wild type and in Jurkat Tat(+) cells. Furthermore, Tat not only induced the participation of c-jun in the cooperative complex but also a decrease in its transactivation activity alone or in combination with c-rel. Thus, the interaction of Tat with the components of this rel/AP1 cooperative complex seems to induce quantitative and qualitative alterations of this complex as activation progresses, resulting in a decrease of IL-2 gene transcription. Altogether our results suggest the existence of tuned mechanisms that allow the viral protein to specifically affect cooperative interactions between transcription factors.

Assembly of truncated HCV core antigen into virus-like particles in Escherichia coli

Core protein is one of the most conserved and immunogenic of the hepatitis C virus proteins. Several pieces of experimental evidence suggest its ability for formation of virus like particles alone or in association with other viral proteins in mammalian or yeast cells with great similarity to those detected in patient sera and liver extract. In this work we report an Escherichia coli-derived truncated hepatitis C core protein that is able to aggregate. SDS-PAGE and size exclusion chromatography patterns bring to mind the aggregation of monomers of recombinant protein Co.120. The Co.120 protein migrated with buoyant density of 1.28 g/cm(3) when analyzed using CsCl density gradient centrifugation. Spherical structures with an average diameter of 30 nm were observed using electron microscopy. We report here that VLPs are generated when the first 120 aa of HCV core protein are expressed in E. coli.

Presence of fed β-carotene in digesta, excreta, blood, and hepatic and adipose tissues of Holstein steers

Eight animals were fed a diet without added β-carotene for 49 d and then supplemented with four levels of β-carotene (0, 5.5, 44 or 352 mg kg–1dry matter) for 30 d; the two-phase procedure was then repeated. Steers were killed at the end of the second period. Concentrations of β-carotene were: 0, 0, 227.2 and 2011 mg dL–1 (P < 0.05) in ruminal fluid; 0, 0, 533.7 and 4418 mg dL–1 (P < 0.05) in duodenal fluid; 0, 4.03, 14.91 and 90.64 mg g–1 (P < 0.05) in dry faeces; 0.8, 1.2, 4.7 and 8.1 mg g–1 (P < 0.05) in liver; 0.07, 0.15, 0.5 and 3.7 mg g–1 (P < 0.05) in subcutaneous fat; 0, 0, 0.09 and 0.23 mg g–1 (P < 0.05) in kidney fat for dietary treatments with 0, 5.5, 44 and 352 mg β-carotene kg–1 DM, respectively. The dose of β-carotene was reflected in retinol concentrations in liver: 101.1, 113.6, 161.7 and 199.6 mg g–1 (P < 0.05), but not in subcutaneous or kidney fat (P > 0.1). The estimated β-carotene digestibilities were 66.25, 84.39 and 88.14% for treatments with 5.5, 44 and 352 mg β-carotene kg–1 DM, respectively (P < 0.01). The results suggest a high capacity of bovine tissues to store β-carotene and probably a limited capability to convert β-carotene into vitamin A. Key words: β-carotene digestion, blood concentration, deposition, steers

Identification of a new water channel (Rp-MIP) in the Malpighian tubules of the insect Rhodnius prolixus

Malpighian tubules (MT) of Rhodnius prolixus transport fluid at very high rates. To identify whether aquaporins (AQPs) are present in the MT of R. prolixus, total ribonucleic acid (RNA) was isolated from MT and used in a reverse transcription, polymerase chain reaction (RT-PCR), with two degenerate primers to highly conserved regions of the members of the AQPs family. A deoxyribonucleic acid (DNA) fragment of 370 bp was amplified; its sequence revealed a novel protein, representing a new member of the major intrinsic protein (MIP) family. The complementary DNA (cDNA) sequence of this new MIP protein was cloned by using RNA from MT and the rapid amplification of cDNA ends (RACE) technique. The cDNA had 1133 bp and the largest open reading frame coded for a protein of 286 amino acids, named R. prolixus major intrinsic protein (Rp-MIP). The hydrophobicity profile of the amino acid sequence predicts six transmembrane domains. Northern blot analysis of MT RNA showed a single transcript of about 1-1.3 kb for Rp-MIP. RT-PCR of single isolated MT and in situ hybridization analysis showed Rp-MIP transcripts in both proximal and distal segments. Expression of Rp-MIP in Xenopus laevis oocytes doubled the osmotic water permeability Pf, indicating that Rp-MIP may function as an aquaporin protein in the MT of the insect and thus may participate in urine formation in R. prolixus.

Immunological and molecular characterization of the major allergens from lilac and privet pollens overproduced in Pichia pastoris

The main allergens from privet and lilac pollens, Lig v 1 and Syr v 1, are proteins homologous to Ole e 1 and have been shown to be involved in cross-reactivity. To overproduce the correctly folded Lig v 1 and Syr v 1 allergens and to study their immunological properties in comparison with those of their natural counterparts. The yeast Pichia pastoris was used as an expression system to produce these recombinant allergens. The proteins were isolated by ion-exchange and size-exclusion chromatographies. Amino acid quantifying, Edman degradation, mass spectrometry and circular dichroism were carried out to obtain molecular properties of the recombinant proteins. Anti-Ole e 1 monoclonal and polyclonal antibodies, as well as sera from patients allergic to olive pollen, were used in immunoblotting and ELISA for immunological characterization. Recombinant Lig v 1 and Syr v 1 were secreted at high yield to the extracellular medium of the yeast. The purified proteins displayed the native conformation, as deduced from their spectroscopic properties and binding ability to an IgG monoclonal antibody. The recombinant allergens behaved similarly to their natural counterparts when they were analysed against Ole e 1-specific antibodies. IgE and IgG binding properties of lilac and privet allergens to olive allergic sera and Ole e 1-specific antibodies indicated that these molecules share common B-cell epitopes with Ole e 1. P. pastoris yeast is an appropriate system for the efficient production of Ole e 1-like allergens, which could be used as analogous allergens and predictors of clinical sensitization.

Biweekly gemcitabine, doxorubicin, and paclitaxel as first-line treatment in metastatic breast cancer. Final results from a phase II trial

In a single-center, open, phase II trial, we assessed the toxicity and activity of a triple combination therapy--doxorubicin at 30 mg/m2 (day 1), paclitaxel (Taxol) at 135 mg/m2 (day 2), and gemcitabine (Gemzar) at 2,500 mg/m2 (day 2 after paclitaxel)--administered biweekly in a 28-day cycle for six cycles. This was given as first-line treatment in 41 patients with metastatic breast cancer. Granulocyte colony-stimulating factor was used in 27 patients to permit maintenance of dose density. Hematologic toxicity was moderate. Nonhematologic adverse events were generally mild. The objective response rate was 82.9% (34/41) with 18 patients (43.9%) achieving complete response and 16 (38%) achieving partial response; progressive disease was observed in 4 patients (9.8%). Responses were observed at all metastatic sites, including complete responses in lung, liver, bone, and soft tissue. Median duration of response was 14.1 months and median time to progression was 13.9 months. Median survival was 26.2 months. The biweekly combination of gemcitabine, doxorubicin, and paclitaxel is safe and highly active as first-line treatment in metastatic breast cancer.

Characterization and functional role of Saccharomyces cerevisiae 2,3-butanediol dehydrogenase

Using a conserved sequence motif, a new gene (YAL060W) of the MDR family has been identified in Saccharomyces cerevisiae. The expressed protein was a stereoespecific (2R,3R)-2,3-butanediol dehydrogenase (BDH). The best substrates were (2R,3R)-2,3-butanediol for the oxidation and (3R/3S)-acetoin and 1-hydroxy-2-propanone for the reduction reactions. The enzyme is extremely specific for NAD(H) as cofactor, probably because the presence of Glu223 in the cofactor binding site, instead of the highly conserved Asp223. BDH is inhibited competitively by 4-methylpyrazole with a K(i) of 34 microM. Yeast could grow on 2,3-butanediol or acetoin as a sole energy and carbon sources, and a 3.6-fold increase in BDH activity was observed when cells were grown in 2,3-butanediol, suggesting a role of the enzyme in 2,3-butanediol metabolism. However, the disruption of the YAL060W gene was not lethal for the yeast under laboratory conditions, and the disrupted strain could also grow in 2,3-butanediol and acetoin. This suggests that other enzymes, in addition to BDH, can also metabolize 2,3-butanediol in yeast.

Performance evaluation of a mesophilic anaerobic fluidized-bed reactor treating wastewater derived from the production of proteins from extracted sunflower flour

A study of the anaerobic digestion of wastewater derived from the production of protein isolates from extracted sunflower flour was carried out in a laboratory-scale, mesophilic (35 degrees C) fluidized-bed reactor with saponite as bacterial support. Chemical oxygen demand (COD) removal efficiencies in the range of 98.3-80.0% were achieved in the reactor at organic loading rates (OLR) of between 0.6 and 9.3 g COD/I d, hydraulic retention times (HRT) of between 20.0 and 1.1 d and average feed COD concentration of 10.6 g/l. Eighty percent of feed COD could be removed up to OLR of 9.3 g COD/l d. The yield coefficient of methane production was 0.33 l of methane (at STP) per gram of COD removed and was virtually independent of the OLR applied. Because the buffering capacity of the experimental system was maintained at favorable levels with excess total alkalinity present at all loadings, the rate of methanogenesis was not affected by loading. The experimental data indicated that a total alkalinity in the range of 2,000-2,460 mg/l as CaCO3 was sufficient to prevent the pH from dropping to below 7.0 for OLR of up to 9.3 g COD/l d. The volatile fatty acid (VFA) levels and the VFA/alkalinity ratio were lower than the suggested limits for digester failure (0.3-0.4) for OLR and HRT up to 9.3 g COD/l d and 1.1 d, respectively. For a HRT of 0.87 d (OLR of 12.1 g COD/l d) the start of acidification was observed in the reactor.

The specific force of single intact extensor digitorum longus and soleus mouse muscle fibers declines with aging

In the present study we measured, for the first time, the isometric specific force (SF, force normalized to cross sectional area) generated by single intact fibers from fast- (extensor digitorum longus, EDL) and slow-twitch (soleus) muscles from young adult (2-6), middle-aged (12-14) and old (20-24 month-old) mice. SF has also been measured in single intact flexor digitorum brevis fibers from young mice. Muscle fibers have been classified into fast- or slow-twitch based on the contraction kinetics. Maximum SF recorded in EDL and soleus fibers from young and middle-aged mice did not differ significantly. A significant age-dependent decline in maximum SF was recorded in EDL and soleus fibers from young or middle-aged to old mice. The SF was 377 +/- 18, 417 +/- 20 and 279 +/- 18 kPa for EDL fibers from young, middle-aged and old mice, respectively and 397 +/- 17, 405 +/- 24 and 320 +/- 33 kPa for soleus fibers from age-matched mice, respectively. The frequency needed to elicit maximum force in EDL and soleus fibers from middle-aged to old mice did not differ significantly. In conclusion, the specific force developed by both fast and slow-twitch single intact muscle fibers declines with aging and more significantly in the former.

Characterization of a (2R,3R)-2,3-butanediol dehydrogenase as the Saccharomyces cerevisiae YAL060W gene product. Disruption and induction of the gene

The completion of the Saccharomyces cerevisiae genome project in 1996 showed that almost 60% of the potential open reading frames of the genome had no experimentally determined function. Using a conserved sequence motif present in the zinc-containing medium-chain alcohol dehydrogenases, we found several potential alcohol dehydrogenase genes with no defined function. One of these, YAL060W, was overexpressed using a multicopy inducible vector, and its protein product was purified to homogeneity. The enzyme was found to be a homodimer that, in the presence of NAD(+), but not of NADP, could catalyze the stereospecific oxidation of (2R,3R)-2, 3-butanediol (K(m) = 14 mm, k(cat) = 78,000 min(-)(1)) and meso-butanediol (K(m) = 65 mm, k(cat) = 46,000 min(-)(1)) to (3R)-acetoin and (3S)-acetoin, respectively. It was unable, however, to further oxidize these acetoins to diacetyl. In the presence of NADH, it could catalyze the stereospecific reduction of racemic acetoin ((3R/3S)- acetoin; K(m) = 4.5 mm, k(cat) = 98,000 min(-)(1)) to (2R,3R)-2,3-butanediol and meso-butanediol, respectively. The substrate stereospecificity was determined by analysis of products by gas-liquid chromatography. The YAL060W gene product can therefore be classified as an NAD-dependent (2R,3R)-2,3-butanediol dehydrogenase (BDH). S. cerevisiae could grow on 2,3-butanediol as the sole carbon and energy source. Under these conditions, a 3. 5-fold increase in (2R,3R)-2,3-butanediol dehydrogenase activity was observed in the total cell extracts. The isoelectric focusing pattern of the induced enzyme coincided with that of the pure BDH (pI 6.9). The disruption of the YAL060W gene was not lethal for the yeast under laboratory conditions. The disrupted strain could also grow on 2,3-butanediol, although attaining a lesser cell density than the wild-type strain. Taking into consideration the substrate specificity of the YAL060W gene product, we propose the name of BDH for this gene. The corresponding enzyme is the first eukaryotic (2R, 3R)-2,3-butanediol dehydrogenase characterized of the medium-chain dehydrogenase/reductase family.

[Diagnostic and clinical course features of lupus membranous glomerulonephritis]

BACKGROUND

Lupus membranous glomerulonephritis (LMG) is sometimes difficult to distinguish from idiopathic membranous glomerulonephritis (IMG) and little is known about its natural history.

METHODS

We have performed a retrospective study of 16 patients with LMG, types Va ("pure" LMG) (8 patients) and Vb (mesangial proliferation) (8 patients). Analytical and clinical characteristics were analyzed in each case at the onset of the disease and during follow-up.

RESULTS

At the time of diagnosis, 7 patients (43%) did not present any extrarenal manifestations of systemic lupus erythematosus (SLE). Nephrotic syndrome was the most common clinical presentation (81%). 14 patients (87%) showed positive antinuclear antibodies (ANA), but at low titres (< 1/300); anti-DNA antibodies were positive only in 3 cases (18%) and hypocomplementemia was observed in 2 (12%). The most relevant histological findings were the presence of Clq deposits (83%) and subendothelial and mesangial deposits. Treatment consisted of corticosteroids, adding immunosuppression when no response was obtained in 2-3 months. In recent years, an angiotensin-converting enzyme inhibitor (ACEI) was added before immunosuppression. At the end of the study, 6 patients (42%) developed chronic renal insufficiency and 8 (58%) renainea with normal renal function. Actuarial renal survival was 100% at 5 years and 75% at 10 years. The evolution towards a non-nephrotic range proteinuria throughout the follow-up was the only parameter significantly associated with a good prognosis.

CONCLUSIONS

LMG can present without extra-renal symptoms of SLE and even with very poor expression of its serological markers. Almost half of the patients (42%) developed chronic renal insufficiency. The evolution towards a non-nephrotic range proteinuria correlated with the maintenance of a normal renal function.

Pancreatic nitric oxide and oxygen free radicals in the early stages of streptozotocin-induced diabetes mellitus in the rat

The objective of the present study was to explore the regulatory mechanisms of free radicals during streptozotocin (STZ)-induced pancreatic damage, which may involve nitric oxide (NO) production as a modulator of cellular oxidative stress. Removal of oxygen species by incubating pancreatic tissues in the presence of polyethylene glycol-conjugated superoxide dismutase (PEG-SOD) (1 U/ml) produced a decrease in nitrite levels (42%) and NO synthase (NOS) activity (50%) in diabetic but not in control samples. When NO production was blocked by N(G)-monomethyl-L-arginine (L-NMMA) (600 microM), SOD activity increased (15.21 +/- 1.23 vs 24.40 +/- 2.01 U/mg dry weight). The increase was abolished when the NO donor, spermine nonoate, was added to the incubating medium (13.2 +/- 1.32). Lipid peroxidation was lower in diabetic tissues when PEG-SOD was added (0.40 +/- 0.02 vs 0.20 +/- 0.03 nmol/mg protein), and when L-NMMA blocked NOS activity in the incubating medium (0.28 +/- 0.05); spermine nonoate (100 microM) abolished the decrease in lipoperoxide level (0.70 +/- 0.02). We conclude that removal of oxygen species produces a decrease in pancreatic NO and NOS levels in STZ-treated rats. Moreover, inhibition of NOS activity produces an increase in SOD activity and a decrease in lipoperoxidation in diabetic pancreatic tissues. Oxidative stress and NO pathway are related and seem to modulate each other in acute STZ-induced diabetic pancreas in the rat.

Alternative splicing regulates the nuclear or cytoplasmic localization of dystrophin Dp71

The subcellular distribution of Dp71 isoforms alternatively spliced for exon 71 and/or 78 was examined. The cDNA sequence of each variant was fused to the C-terminus of the green fluorescent protein and the constructs were transfected transiently in the cell lines HeLa, C2C12 and N1E-115. The subcellular distribution of the fused proteins was determined by confocal microscope analysis. The Dp71 isoform lacking the amino acids encoded by exons 71 and 78 was found exclusively in the cytoplasm whereas the variants containing the amino acids encoded by exon 71 and/or exon 78 show a predominant nuclear localization. The nuclear localization of Dp71 provides a new clue towards the establishment of its cellular function.

Phase II trial of gemcitabine/doxorubicin/paclitaxel administered every other week in patients with metastatic breast cancer

The present trial was designed to determine the efficacy of the combination of gemcitabine/doxorubicin/paclitaxel (GAT) delivered every other week as first-line therapy in patients with metastatic breast cancer. From February 1998 to September 1999, 41 patients were included in this trial. Doses delivered were doxorubicin 30 mg/m2 on day 1 and paclitaxel 135 mg/m2 plus gemcitabine 2500 mg/m2 both given on day 2, every 14 days. Doses were selected from a previous phase I trial conducted at our institution. Eligibility criteria for the phase II trial included histologically confirmed metastatic breast cancer with bidimensionally measurable lesions; no prior therapy for metastatic disease; adjuvant or neoadjuvant chemotherapy was allowed if given more than 1 year before and cumulative doses of doxorubicin or epirubicin were less than 200 mg/m2 or 360 mg/m2, respectively; Eastern Cooperative Oncology Group (ECOG) performance status of 2 or less; and adequate hematological, hepatic, and renal function. Prophylactic use of granulocyte colony-simulating factor (G-CSF) was allowed if patients were not fully recovered (absolute neutrophil count greater than 1500/microL) from chemotherapy administration before the next dose. Left ventricular ejection fraction was determined initially, at the end of the study, and every 6 months thereafter. The patients' median age was 55 years (range, 33-68 years), and their median ECOG performance status was 0 (range, 0-1). Twenty-eight patients had received adjuvant therapy, 17 with epirubicin (none with doxorubicin). Metastases were present in the bone (19 patients), lung (19 patients), liver (11 patients), and soft tissues (18 patients). Twenty patients had one metastatic site and 21 had two or more sites. Efficacy was assessed on an intent-to-treat basis. A total of 216 cycles of GAT were given. Twenty-two percent of the courses were delayed or given at reduced doses mostly due to neutropenia or thrombocytopenia. G-CSF was required in 58% of the cycles. Grade 3/4 neutropenia was the main toxicity and appeared in 17 patients, one of whom had an episode of febrile neutropenia. Nonhematological toxicities consisted mainly of neurotoxicity and myalgias. A drop of 10%-20% in the left ventricular ejection fraction was detected in two patients and another patient had a decrease greater than 20%, although none developed symptoms of heart failure. Overall response rate was 80.4% (95% confidence interval: 68.3-92.5), with 15 patients (36.6%) achieving a complete response. Median survival time was 27 months and median time to progression was 15 months. The GAT combination is feasible and very active in patients with metastatic breast cancer, with an encouraging response rate including a high rate of complete responses. No congestive heart failure was documented and other toxicities were mild, with the exception of neutropenia.