Clinical characteristics of vulnerable populations hospitalized and diagnosed with COVID-19 in Buenos Aires, Argentina

There is not in Argentina publications regarding the presentation of patients with COVID-19 requiring hospitalized and emergency care in vulnerable populations (lower incomes and less education tend at greater risk for poor health status and healthcare access), and it has few reports in developing countries. The objective is to determine whether in the care of vulnerable patients, to succeed against COVID-19, multiple public health tools and interventions will be needed to minimize morbidity and mortality. The study is a prospective cohort investigation of patients with lab-confirmed COVID-19, who required to any of the Health Centers response from April 8, 2020, to August 18, 2020. In Buenos Aires Metropolitan Area (AMBA), April 8, 2020 the virus was identified in patients hospitalized in the "Southeast Network" (SN), AMBA. SN covering an area of 661 square kilometers, with 1.8 million inhabitants residing in urban, and rural areas. A total of 14 health centers with different levels of care complexity provide care to patients in the region. The information of each patient with COVID-19 evaluated by SN, was incorporated in an Epidemiological Dashboard. The investigation was designed and reported with consideration of observational studies in epidemiology. We describe the hospitals presentation and care of persons who required SN response and were ultimately diagnosed with COVID-19. From April 8, 2020, to August 18, 2020, were included 1495 patients with lab-confirmed COVID-19 in SN. A total of 58% patients were men, and the mean age (SD) was 48.9 (15.59) years. Eighty one percent patients with pre-existing diseases, most frequent hypertension and diabetes, but hypertension, chronic lung disease, and cardiovascular disease presented higher risk. A total of 13% were hospitalized in Intensive Therapy Unit. The mortality of the cohort was 9.77%. Mortality was higher for patients aged 65 or more (OR 5.09), and for those had some pre-existing disease (OR 2.61). Our observations are consistent with reports demonstrating older persons, and those with comorbidities have the highest risk of mortality related to COVID-19. However, unlike other reports from developed or some developing countries, the mortality in our study is lower. This finding may be related to age of our cohort is younger than other published. Also, the health system was able to respond to the demand.

The exploration of a new environment leads to the modulation of gene expression for prolonged times in the rat

In the present study we performed a transcriptional analysis in order to evaluate changes in gene expression induced by exploration in prolonged times. The analysis was carried out 3, 10 and 20 days after exploration. We analyzed the modulation of the expression levels of Pfn2, Casp3, Pdrg1, Pea15, Ywhaz genes which previously were found not modulated 2 days after exploration. Our data show that the expression of Pfn2, Casp3, Pdrg1, Pea15, Ywhaz genes was modulated at 10 or 20 days. The transcript, whose expression had been evaluated with the qRT-PCR, code for proteins which belong to the following functional categories: synaptic modulation, apoptosis, signal transduction. It is interesting to note that the modulation of the expression of these genes was evident some days after environmental exploration, and not previously at 2 days after conditioning as occurred after contextual fear conditioning (CFC). Hence it is possible to hypothesize that the spatial memory processes require a longer period of elaboration than the emotional ones, fundamental for the survival of the species.

Contextual fear conditioning modulates the gene expression over time

Contextual fear conditioning (CFC) is a quick cognitive test based on the association context-aversive stimulus in which a single training leads to a long-term memory. Previously, we showed that 2 days after conditioning the expression of the genes Napa, Pnf2, Casp3, Pdrg1, Ywhaz, Stmn1, Bpgm, were positively modulated in CFC rats respect to naïve rats, explor rats which had freely explored the experimental apparatus and SO rats to which the same number of aversive shocks used in CFC paradigm had been administered in the same CFC apparatus in less time to prevent the association between painful stimuli and apparatus, whereas the genes Actr3, Pea15 and Tiprl were more expressed in SO rats and Cplx1, Trim32 and Ran genes were more expressed in explor rats. At 2 days, Tomm20 gene expression resulted positively modulated in both CFC and explor rats. Herein, we have tested the expression of these genes for a period longer than 2 days, by monitoring the modulation of transcripts within 20 days after conditioning. The expression of the transcripts was assessed by qRT-PCR.We found that three days after CFC only the genes Tiprl and Trim32 were positively modulated in CFC rats whereas the gene Tomm20 was negatively modulated in CFC rats as well as in SO and explor rats. Ten days after CFC, the expression of Trim32 was still positively modulated whereas the genes Tiprl and Tomm20 returned to the constitutive level, and the gene Ran was significantly more expressed in CFC rats than in naïve, SO and explor rats. Interestingly, 20 days after CFC, the genes Stmn1 and Tiprl again became significantly more expressed in CFC rats compared with naïve, SO and explor rats.

The Effect of Fibrinolysis Inhibitors on the Ellagic Acid Activation of Hageman Factor in the Dog

The administration of 10 ml/kg b.w. of a 10−4 M ellagic acid solution to dogs primed with saline (control group) caused a marked shortening of the silicone clotting time and a mild shortening of the glass clotting time whereas no changes in the euglobulin lysis time were noted. The administration of the compound to dogs primed with Trasylol (10,000 K.I.U./kg b.w.) failed to cause any change in the clotting times but caused instead a sharp inhibition of fibrinolysis. The administration of ellagic acid to dogs primed with EACA (0.3 g/kg b.w.) caused a shortening of the silicone and glass clotting times similar to that observed in the control group whereas fibrinolysis was not significantly inhibited. These data indicate that Trasylol inhibits Hageman factor activation by ellagic acid whereas EACA has no effect.

Physical Exercise Improves Total Antioxidant Capacity and Gene Expression in Rat Hippocampal Tissue

Exercise may exert beneficial effects on cognitive functions and play an important role in the prevention of neurodegenerative diseases. Such effects seem to be mediated by changes in anti-oxidative status, but limited information is available on the nature of molecular pathways supporting the antioxidant effects of exercise in the brain. In this study 3-5-month-old male Wistar albino rats were subjected to three times/week moderate intensity exercise on a rodent treadmill for a period of 6 weeks. The tissue antioxidant activity towards various reactive oxygen species (ROS) was determined in the hippocampus. In addition, to identify the molecular pathways that may be involved in ROS metabolism, the expression of nerve growth factor (NGF) and sirtuins (SIRT1 and SIRT3) were measured. Our results showed a higher antioxidant activity in the hippocampus of physically trained rats compared to sedentary controls. Furthermore, exercise induced an up-regulation of NGF, possibly related to an improved redox balance in the hippocampus. These results suggest that physical exercise might prevent age-induced oxidative damage in the hippocampus.

[Implementing clinical pathways: some practical notes]

The traditional biomedical paradigm is no longer a guarantee of quality for health care, facing increasingly difficult challenges caused by chronic diseases and increasingly fragmented resources that current healthcare systems are dealing with. Health care organizations, considered to be the most complex enterprises of the modern era, must be able to focus on the flow of patients, integrating primary and secondary care through tools such as the Integrated Care Pathways (ICP). This brief discussion attempts to define the ICP its purposes, the elements that characterize it, its limitations and the mechanisms to push for a successful implementation. In order to highlight the elements and basic steps for the creation of an ICP, the authors have compared five different clinical pathways, whose implementation they have contributed to. The comparison was made using two grids: the first showing the essential elements for the definition of lCP and the second one with features that can facilitate their effectiveness. The conclusions of the work show what, pursuing the construction of a pathway, we must never forget: to analyze the gap between the clinical-care activities performed and the theoretical framework provided by the evidence; to see the barriers to change that may impede the implementation; to involve all actors in the system, with particular attention to patients and their associations, and finally to provide a plan for information and education, addressed to health professionals and patients as well.

Abstract S6-10: Identification of a Novel Tumor Suppressor Network Reveals a Role for Proto-Oncogenic Receptor Tyrosine Kinases in Triple-Negative Breast Cancer

Breast cancer is a collection of diseases with distinct clinical behaviors and underlying genetic causes. Triple-negative breast cancer (TNBC) is a common subtype of breast cancer that confers a particularly poor prognosis and is refractory to current targeted therapies. Unfortunately, the molecular determinants driving this aggressive malignancy are poorly understood. Using an unbiased genetic screen, we have identified a novel tumor suppressor network that governs proliferation and transformation of TNBCs in vitro and in vivo. We define SECT21 as a core component in this network and a commonly inactivated tumor suppressor in TNBC. SECT21 is a potent suppressor of human mammary epithelial cell proliferation and transformation. SECT21 function is frequently compromised in human TNBCs by inactivating mutations, deletion, or loss of protein expression. Mechanistically, SECT21 is a tyrosine phosphatase that suppresses cellular transformation by interacting with and inhibiting several oncogenic receptor tyrosine kinases including HER2, EGFR, and PDGFR. Notably, the tumorigenic and metastatic potential of SECT21-deficient TNBCs is severely impaired by restoring SECT21 function or by inhibiting kinase targets of SECT21, suggesting that TNBCs are dependent on the proto-oncogenic tyrosine kinases constrained by SECT21. Collectively, these data identify SECT21 as a commonly inactivated tumor suppressor and provide a rationale for combinatorially targeting tyrosine kinases in TNBC and other cancers based on their profile of tyrosine phosphatase activity.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr S6-10.

Regulation of apoptosis by PML and the PML-NBs

The promyelocytic leukemia protein (PML) is a tumor suppressor identified in acute PML and implicated in the pathogenesis of a variety of tumors. PML is essential for the proper assembly of a nuclear macromolecular structure called the PML nuclear body (PML-NB). PML and PML-NBs are functionally promiscuous and have been associated with the regulation of several cellular functions. Above all these is the control of apoptosis, a function of PML whose physiological relevance is emphasized by in vivo studies that demonstrate that mice and cells lacking Pml are resistant to a vast variety of apoptotic stimuli. The function of PML in regulating apoptosis is not confined to a linear pathway; rather, PML works within a regulatory network that finely tunes various apoptotic pathways, depending on the cellular context and the apoptotic stimulus. Here, we will summarize earlier and recent advances on the molecular mechanisms by which PML regulates apoptosis and the implication of these findings for cancer pathogenesis.

Ribosomal RNA characterization in the leech Hirudo medicinalis

In the present study the ribosomal RNA of the leech Hirudo medicinalis has been characterized at the aim of identifying possible analogies with other invertebrates. Upon electrophoresis on denaturating gels, ribosomal RNA fraction of H. medicinalis exhibited a remarkable thermal instability by dissociating into two hydrogen-bonded components when heated at 60 degrees C, at variance with the behaviour of the rat rRNA, which does not show this process. This result suggests a functional role in leech ribosome organisation that requires deeper structural studies.

Alpha-tryptophan synthase of Isatis tinctoria: gene cloning and expression

Indole producing reaction is a crux in the regulation of metabolite flow through the pathways and the coordination of primary and secondary product biosynthesis in plants. Indole is yielded transiently from indole-3-glycerol phosphate and immediately condensed with serine to give tryptophan, by the enzyme tryptophan synthase (TS). There is evidence that plant TS, like the bacterial complex, functions as an alpha beta heteromer. In few species, e.g. maize, are known enzymes, related with the TS alpha-subunit (TSA), able to catalyse reaction producing indole, which is free to enter the secondary metabolite pathways. In this contest, we searched for TSA and TSA related genes in Isatis tinctoria, a species producing the natural blue dye indigo. The It-TSA cDNA and the full-length exons/introns genomic region were isolated. The phylogenetic analysis indicates that It-TSA is more closely related to Arabidopsis thaliana At-T14E10.210 TSA (95.7% identity at the amino acid level) with respect to A. thaliana At-T10P11.11 TSA1-like (63%), Zea mays indole-3-glycerol phosphate lyase (54%), Z. mays TSA (53%), and Z. mays indole synthase (50%). The It-TSA cDNA was also able to complement an Escherichia coli trpA mutant. To examine the involvement of It-TSA in the biosynthesis of secondary metabolism compounds, It-TSA expression was tested in seedling grown under different light conditions. Semi-quantitative RT-PCR showed an increase in the steady-state level of It-TSA mRNA, paralleled by an increase of indigo and its precursor isatan B. Our results appear to indicate an involvement for It-TSA in indigo precursor synthesis and/or tryptophan biosynthesis.

The leukemia-associated cytoplasmic nucleophosmin mutant is an oncogene with paradoxical functions: Arf inactivation and induction of cellular senescence

Mutations leading to aberrant cytoplasmic localization of Nucleophosmin 1 (NPM1) have been recently identified as the most frequent genetic alteration in acute myelogenous leukemia. However, the oncogenic potential of this nucleophosmin mutant (NPMc+) has never been established, which casts doubt on its role in leukemogenesis. By performing classical transformation assays, we find that NPMc+, but not wild-type NPM, cooperates specifically with adenovirus E1A to transform primary mouse embryonic fibroblasts in soft agar. We demonstrate that NPMc+ blocks the p19(Arf) (Arf) induction elicited by E1A. Surprisingly, however, we find that NPMc+ induces cellular senescence and that E1A is able to overcome this response. We propose a model whereby the NPMc+ pro-senescence activity needs to be evaded for oncogenic transformation, even though NPMc+ can concomitantly blunt the Arf/p53 pathway. These findings identify for the first time NPMc+ as an oncogene and shed new unexpected light on its mechanism of action.

[Metabolic syndrome and hypertension: prevention and treatment]

Since the 1950s the definition of the aggregate of metabolic disorders possibly presenting with adult obesity has evolved without reaching a unifying agreement on what metabolic syndrome is. After years of consensus on and research into identifying the extent to which certain criteria of metabolic syndrome may be predisposing factors for cardiovascular events, a reverse shift can be noticed in recent studies raising numerous points of contention about various elements that may be diagnostic for the syndrome. Of these, one of the most tenuous is probably arterial hypertension. Uncertainties have emerged regarding the arbitrariness of cut-off values, which differ according to the classification system the study applied, the methods of measurement, and the dilemma of hyperinsulinemia/insulin resistance which is present in only 50-60% of individuals with hypertension. Currently available data fail to solve these conundrums; however, some studies have correlated hypertension and dislipidemia with an increased risk of cardiovascular events. International epidemiologic data indicate that the prevalence of the syndrome varies between populations and between the sexes within the same populations, suggesting that diagnostic criteria need to take better account of ethnic group origin. Prevention of metabolic syndrome is still based on lifestyle changes; the huge risk of an imminent pandemic has called the attention of the American Heart Association to the importance of prevention and early treatment of the pediatric population--a new segment at risk of early cardiovascular events. Pharmacological therapy is directed at controlling various risk factors, particularly hypertension and metabolic disturbances. ACE inhibitors, sartans and statins are currently the drugs of first choice in treating metabolic syndrome.

EFFECTS OF SIBERIAN GINSENG (ELEUTHEROCOCCUS SENTICOSUS MAXIM.) ON ELDERLY QUALITY OF LIFE: A RANDOMIZED CLINICAL TRIAL

An unspecific feeling of fatigue and asthenia often pushes elderly patients to require any form of help even from non medically trained people. Traditional Chinese medicine suggest that Siberian ginseng could act as safe "adaptogenic" substance. Our aim was thus to test the effect of a middle term Eleutherococcus senticosus Maxim. (Araliaceae) administration on elderly, health related quality of life (HRQOL). 20 elderly hypertensive and digitalized volunteers (age >/= 65 years) were randomized in a double -blind manner to E. senticosus dry extract 300 mg/day (n = 10) or placebo (n = 10) for 8 weeks. The short form-36 health survey version 2 (SF-36v2), a validated general health status questionnaire, was used to access HRQOL at baseline and at 4 and 8 weeks. There were no significant differences in baseline demographics and SF-36v2 scores between the groups. At each visit, controls of digitalemia and blood pressure level were carried out. After 4 weeks of therapy, higher scores in social functioning (p = 0.02) scales were observed in patients randomized to E. senticosus; these differences did not persist to the 8-week time point. No adverse event has been observed in both groups of patients. No significant difference in both blood pressure control and digitalemia was observed in both treatment groups. Subjects give E. senticosus (70%) were more likely to state that they received active therapy than subjects given placebo (20%; p < 0.05). In conclusion, E. senticosus safely improves some aspects of mental health and social functioning after 4 weeks of therapy, although these differences attenuate with continued use.

Effect of pilocarpine mouthwash on salivary flow

Pilocarpine is a cholinergic agonist that increases salivary flow and has been used to treat xerostomia. Oral intake is the most frequent route of administration. Adverse effects are dose-dependent and include sudoresis, facial blushing and increased urinary frequency. The objective of the present study was to evaluate the effects of topical pilocarpine solutions as mouthwashes on salivary flow and their adverse effects on healthy subjects. Forty volunteers received 10 ml 0.5, 1 and 2% pilocarpine solutions or 0.9% saline in a randomized, double-blind, placebo-controlled manner. Salivation was measured before and 45, 60 and 75 min after mouth rinsing for 1 min with 10 ml of saline or pilocarpine solutions. Vital signs were measured and ocular, gastrointestinal and cardiovascular symptoms, anxiety and flushing were estimated using visual analog scales. There was a dose-dependent increase in salivation. Salivation measured after 1 and 2% pilocarpine (1.4 +/- 0.36 and 2.22 +/- 0.42 g, respectively) was significantly (P<0.001) higher than before (0.70 +/- 0.15 and 0.64 +/- 0.1 g), with a plateau between 45 and 75 min. Cardiovascular, visual, gastrointestinal and behavioral symptoms and signs were not changed by topical pilocarpine. Mouth rinsing with pilocarpine solutions at concentrations of 1 to 2% induced a significant objective and subjective dose-dependent increase in salivary flow, similar to the results reported by others studying the effect of oral 5 mg pilocarpine. The present study revealed the efficacy of pilocarpine mouthwash solutions in increasing salivary flow in healthy volunteers, with no adverse effects. Additional studies on patients with xerostomia are needed.

Combination of 1alpha,25-dihydroxyvitamin D(3) with dexamethasone enhances cell cycle arrest and apoptosis: role of nuclear receptor cross-talk and Erk/Akt signaling

Previously we have shown that dexamethasone (DEX) enhances the antitumor activity and ligand binding of the active form of vitamin D, 1alpha,25-dihydroxyvitamin D(3) (1,25-D(3)), in the murine squamous cell carcinoma model SCC VII/SF. DEX also reduces the hypercalcemia toxicity of 1,25-D(3) treatment. However, the mechanism of the enhanced antitumor activity has not been defined. Here, we demonstrate that both cell cycle arrest and apoptosis were enhanced by DEX, effects that were inhibited by RU486. We also demonstrate that vitamin D receptor (VDR) protein levels were increased by the combination of 1,25-D(3) and DEX above the level observed with 1,25-D(3) treatment alone, whereas protein levels of the heterodimeric partner of VDR, retinoid X receptor, were lower for the combination than for 1,25-D(3) alone. Glucocorticoid receptor protein levels and ligand binding were increased by 1,25-D(3) but not by the combination. Treatment with the combination of 1,25-D(3) and DEX did not result in greater activation of a vitamin D response element-reporter than 1,25-D(3) alone or of a glucocorticoid response element-reporter than DEX alone. Nevertheless, the levels of phospho-Erk1/2 and phospho-Akt, signaling molecules that are modulated in 1,25-D(3)-treated squamous cell carcinoma cells, were reduced by the combination of 1,25-D(3) and DEX more than by either agent alone. These trends were also observed in vivo. Our results suggest the involvement of the Erk and Akt signaling pathways in the antiproliferative effects of the combination of 1,25-D(3) and DEX and that phospho-Erk1/2 and phospho-Akt may be useful markers of response to this combination.

Preparation and biological activity of four epiprogoitrin myrosinase-derived products

(5R)-5-Vinyl-1,3-oxazolidine-2-thione, (2S)-1-cyano-2-hydroxy-3-butene, and two diastereoisomeric erythro-(2S)- and threo-(2S)-1-cyano-2-hydroxy-3,4-epithiobutanes were prepared in pure form starting from (2S)-2-hydroxybut-3-enyl glucosinolate (epiprogoitrin). This glucosinolate was isolated in almost pure form using ripe seeds of Crambe abyssinica and then hydrolyzed under different conditions. The hydrolysis was carried out using either myrosinase immobilized on nylon, to produce (5R)-5-vinyl-1,3-oxazolidine-2-thione, or the endogenous myrosinase contained in defatted crambe meals, to produce the other epiprogoitrin-derived products. After purification and physicochemical characterization, all four myrosinase degradation products were tested for their biological activity. A bioassay on Lactuca sativa was chosen as a simple test to determine their apparent action on living tissues. (5R)-5-Vinyl-1,3-oxazolidine-2-thione negatively affected mainly root growth, whereas (2S)-1-cyano-2-hydroxy-3-butene affected the early phase of germination, and both (2S)-1-cyano-2-hydroxy-3,4-epithiobutane diastereoisomers appeared to negatively affect both germination and root growth at doses 5-10 times lower than those of (2S)-1-cyano-2-hydroxy-3-butene or (5R)-5-vinyl-1,3-oxazolidine-2-thione.

Cdc25A stability is controlled by the ubiquitin-proteasome pathway during cell cycle progression and terminal differentiation

Members of the cdc25 family are protein phosphatases that play pivotal roles in cell cycle progression. Cdc25A has been shown to be a critical regulator of the G1/S transition of mammalian cells and to be a myc-target gene with oncongenic properties. We investigated the regulation of cdc25A during terminal differentiation using myeloblastic leukemia M1 cells, that can be induced to undergo differentiation into macrophages by interleukin-6 (IL-6) treatment. In this report it is shown that cdc25A protein is degraded by the ubiquitin-proteasome machinery in both terminally differentiating and cycling cells. Cdc25A was found to have two major peaks of accumulation during cell cycle progression, one in G1 and the other in S/G2. Evidence was obtained that degradation of cdc25A by the ubiquitin-proteasome machinery in terminally differentiating myeloid cells is accelerated compared to cycling cells. Moreover, deregulated expression of c-myc in M1 cells, which had been previously shown to block terminal differentiation, was also found to block IL-6 induced degradation of cdc25A.

Isolation of the epithiospecifier protein from oil-rape (Brassica napus ssp. oleifera) seed and its characterization

The epithiospecifier protein (ESP) is a myrosinase (MYR) cofactor, which is necessary to drive the MYR-catalyzed hydrolysis of some specific glucosinolates towards the production of cyanoepithioalkanes instead of isothiocyanates and nitriles. ESP was isolated from Brassica napus seeds by anionic exchange and gel filtration chromatography. ESP showed a molecular weight of about 39 kDa and pI 5.3. The amino acid sequence of several tryptic peptides of ESP (accounting for about 50% of the total sequence) made it possible to establish the high similarity (81% identity) with a hypothetical 37 kDa protein (TrEMBL data base accession number Q39104) and several jasmonate-inducible proteins from Arabidopsis thaliana. This observation suggests that ESP is likely to be involved in jasmonate-mediated defence and disease resistance mechanisms.

Formation of glucoraphanin by chemoselective oxidation of natural glucoerucin: a chemoenzymatic route to sulforaphane

A new semi-synthetic way to produce glucoraphanin (2), the bio-precursor of the potential anticarcinogen sulforaphane (3), has been developed. Starting from glucoerucin (1), isolated from ripe seeds of Eruca sativa, glucoraphanin was obtained through chemoselective oxidation. Controlled myrosinase-catalysed hydrolysis of this precursor quantitatively afforded sulforaphane.

Apoptosis-prone phenotype of human colon carcinoma cells with a high level amplification of the c-myc gene

Although apoptosis can be induced by the enforced expression of exogenously introduced c-myc genes, it is not clear whether overexpression resulting from the amplification of the resident c-myc gene in tumor cells is sufficient to induce apoptosis. We have investigated the relationship between c-myc gene amplification and the propensity of tumor cells to undergo apoptosis, using the SW613-12A1 and SW613-B3 cell lines, which are representatives, respectively, of tumorigenic and non-tumorigenic clones isolated from the SW613-S human colon carcinoma cell line. Tumorigenic clones are characterized by a high level of amplification and expression of the c-myc gene, whereas cells of non-tumorigenic clones have a small number of copies and a lower level of expression of this gene. Analysis of c-myc mRNA level in cells cultured under low serum conditions indicated that the expression of the gene is tightly regulated by serum growth factors in non-tumorigenic B3 cells, whereas it is poorly regulated in tumorigenic 12A1 cells, the level of mRNAs remaining relatively high in serum-starved 12A1 cells. Under these conditions, 12A1 cells showed clear evidence of apoptosis, whereas B3 cells were completely refractory to the induction of apoptosis. Moreover, the study of cell lines derived from non-tumorigenic apoptosis-resistant clones following the introduction by transfection of exogenous c-myc gene copies showed that they have acquired an apoptosisprone phenotype. Altogether, our results strongly suggest that deregulated c-myc expression due to high-level amplification confers an apoptosis-prone phenotype to tumor cells. The possible consequences of these observations for cancer therapy are discussed.

Poly(ADP-ribose) synthesis: a useful parameter for identifying apoptotic cells

Cell death by apoptosis was analysed in HeLa cells either treated with the antitumoral drug bleomycin or depleted of growth factors by long-term culture without medium change. The interference of apoptosis with normal cell cycle progression was followed by flow cytometry in cells stained with propidium iodide and with antibody to S-phase-related PCNA protein. Bleomycin-treated cells showed a net accumulation in G2/M phase paralleled by the appearance of material with a subdiploid DNA content. Cells with a subdiploid DNA content were also present in growth factor-depleted cultures and were shown to derive from all the cell cycle phases. To identify apoptotic features in HeLa cell cultures, we applied a recently developed assay based on the simultaneous analysis in the single cell of three parameters, namely chromatin condensation, DNA degradation and poly(ADP-ribose) synthesis. Apoptotic cells were visualized by sequential reactions: Hoechst staining, terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labelling assay and immunoreaction with anti-poly(ADP-ribose) monoclonal antibody. Positive reactions were obtained for cells at different stages of the apoptotic programme showing condensed nuclei, fragmented chromatin and apoptotic bodies.

Development of a malignant peripheral nerve sheath tumor following treatment for testicular seminoma

A novel case is reported in which an S2 nerve root malignant peripheral nerve sheath tumor was diagnosed approximately 8 years after treatment for Stage I testicular seminoma. This patient underwent right orchiectomy and subsequent irradiation therapy to the periaortic region, including the sacrum. Postoperative radiation therapy likely played a role in the development of this second malignancy.

Multiparametric staining to identify apoptotic human cells

To analyze relevant features of HeLa and HL60 cells driven into apoptosis by etoposide, we have developed a new "tricolor" assay, based on the simultaneous analysis in the single cell of chromatin condensation, DNA degradation, and cellular poly(ADP-ribose) synthesis. The latter reaction is catalyzed by poly(ADP-ribose)-polymerase (E.C. 2.4.2.30), an enzyme which is activated by the presence of DNA free ends. The protocol consists in the visualization of apoptotic cells by Hoechst staining, TUNEL assay, and immunoreaction with anti-poly(ADP-ribose) antibody. We thus provide the first evidence that endogenous poly(ADP-ribose) production is indeed stimulated in cells undergoing apoptosis after treatment with antitumoral drugs, and that the monitoring of this endogenous enzymatic reaction, combined with morphological and other biochemical parameters, should facilitate the detection of apoptotic cells.

Surgical management of nontuberculous thoracic and lumbar vertebral osteomyelitis: report of 33 cases

BACKGROUND

Thirty-three patients with nontuberculous pyogenic thoracic and lumbar vertebral osteomyelitis were treated surgically. Indications for surgery were either progression of disease despite adequate antibiotic therapy, neurologic deficit, or both. The most common initial symptom was back pain. Seven patients had diabetes, seven patients were intravenous drug users, two patients were receiving immunosuppressive therapy, and seven patients had a debilitating disease. Eleven had infections elsewhere in their bodies. Prior to surgery organisms were grown from blood in 10 patients and at surgery in 15 patients.

METHODS

Infection was evident on plain films in all patients, and either a CT scan or MRI was obtained in each. The lateral extracavitary approach was used for resection of granulation tissue and infected bone ventral to the dura. Interbody bone grafts were placed in 19 patients, usually when bone resection was extensive. Posterior instrumentation was placed in 17 patients at a second procedure 10 days-2 weeks following initial operation. Intravenous antibiotics were administered for 4-6 weeks following surgery, and solid fusion was obtained in all patients.

RESULTS

Neurologic deficit was present in 28 patients prior to surgery and was functionally significant in 18 patients. Of the 11 patients with severe paraparesis, 10 achieved good functional recovery. These patients were able to walk, three with assistance and seven without, and all those who were unable to void regained this ability.

CONCLUSIONS

Surgical debridement, interbody fusion, and posterior instrumentation is a safe and effective treatment for vertebral osteomyelitis and is indicated when neurologic deficit or bone destruction progress despite adequate antibiotic therapy.

Analysis of poly(ADP-ribose) glycohydrolase activity in nuclear extracts from mammalian cells

We have analysed poly(ADP-ribose) glycohydrolase, the enzyme responsible for in vivo degradation of ADP-ribose polymers, by means of a biochemical assay based on the capacity of the enzyme to use a synthetic 32P-labelled polymer as a substrate. The visualization of the reaction has been achieved by separation of poly and mono(ADP-ribose) by thin-layer chromatography followed by autoradiography, whereas polymer hydrolysis has been quantified by counting the spots corresponding to poly and mono(ADP-ribose). By addition of the enzyme inhibitor ethacridine to the reaction mixture, we have confirmed the specificity of the procedure we have developed. The protocol has been applied to study the specific activity of glycohydrolase in nuclear extracts from different mammalian cell lines and to an apoptotic experimental system, namely HL60 cells treated with etoposide. We have observed the activation of the enzyme after a two-hour drug treatment, that is concomitant with the activation of poly(ADP-ribose) polymerase, the enzyme which synthesizes the polymer. These data suggest a precise regulation of ADP-ribosylation process during cell death by apoptosis.

Sequence of events leading to apoptosis in long term cultured HeLa cells

We have maintained HeLa cells in culture in the original medium for increasing times to induce growth arrest. Cell viability was evaluated by trypan blue dye exclusion assay. We observed that when cells are maintained in culture for several days, morphological hallmarks of apoptosis become evident. DNA synthesis rate, followed by (3)H-thymidine incorporation slowed down in long term cultured cells. This evidence was supported by the analysis of cell cycle progression determined by proliferating cell nuclear antigen (PCNA) immunostaining. Apoptotic cells have been characterized with respect to the sequential appearance of high molecular weight and internucleosomal DNA fragmentation. We have provided evidence that in this experimental model the first step in DNA degradation is represented by the formation of high molecular weight fragments, whereas nucleosomal DNA ladder is visible later on. The activation of the enzyme poly(ADP-ribose)polymerase, considered a marker of apoptotic death, has been observed. The results suggest that long term culture conditions activate the apoptotic programme.

Isolation and some molecular properties of a trypsin-like enzyme from larvae of European corn borer Ostrinia nubilalis Hübner (Lepidoptera: Pyralidae)

A one-step high-yielding procedure is presented for the purification of a trypsin-like proteinase from Ostrinia nubilalis larvae, consisting of benzamidine-sepharose affinity chromatography. The purified enzyme was homogeneous as judged by SDS-PAGE. The enzyme presents a molecular mass of 24 650 Da, a maximum pH activity profile of 9.5, a remarkable thermal stability and an optimum temperature of about 53 degrees C Km values determined using N alpha-benzoyl-DL-arginine-ethylester and N alpha-benzoyl-DL-arginine-p-nitro-anilide were 3.2 x 10(-5) M and 4.1 x 10(-4) M respectively. The proteinase was inhibited by some typical serine proteinase inhibitors such as N alpha-tosyl-L-lysine chloromethyl ketone, soybean trypsin inhibitors, benzamidine and phenylmethylsulfonyl fluoride. In particular, it was competitively inhibited by benzamidine with a Ki of 1.2 x 10(-5) M, whereas it was not affected by cysteine proteinases inhibitors. Comparative analysis of the amino acid composition and N-terminal sequence of O. nubilalis proteinase confirmed that this enzyme is very similar to other serine proteinases from lepidopteran larvae.

Warfarin-induced spondyloarthropathy with pseudotumor-like appearance. A case report

STUDY DESIGN

This case report illustrates an unusual complication of chronic warfarin administration.

OBJECTIVES

The presurgical determination that the destructive process at L1-L2 was not infection or neoplasm involved the recognition that there was instability at this level resulting from chronic stress fractures.

SUMMARY OF BACKGROUND DATA

Periosteal or osseous hemorrhagic masses (pseudotumors) have been well described in patients with hemophilia. To the authors' knowledge, this is the first reported case of this well-known phenomenon occurring in the axial skeleton as a consequence of warfarin administration.

METHODS

Serial radiographic studies of the lumbar spine were available showing a progressive destructive lesion at L1-L2 and coinciding with the initiation of warfarin anticoagulation after aortic valve replacement.

RESULTS

The destructive mass was demonstrated surgically to represent a large partially solidified chronic hematoma.

CONCLUSIONS

Patients with stress fractures of the posterior arch and subsequent instability may be subject to development of such a spondyloarthropathy. Recognition of this unusual potential complication of warfarin therapy would prevent an incorrect diagnosis of tumor or infection. Early recognition of its occurrence could lead to early spinal stabilization.

Syringomyelia after removal of benign spinal extramedullary neoplasms

STUDY DESIGN

This is a case report.

OBJECTIVES

Two patients with noncommunicating syringomyelia manifesting symptoms years after the uneventful excision of a benign intradural extramedullary neoplasms are presented.

SUMMARY OF BACKGROUND DATA

The association of noncommunicating syringomyelia with benign extramedullary neoplasms as a coexistent or delayed process is a rare event. The pathogenesis of such spinal cord cavitation after tumor removal and the relationship with therapeutic intervention is not well defined.

METHODS

The delayed occurrence of neurologic impairment emphasizes the need for considering development of syringomyelia rather than tumor recurrence.

RESULTS

The effects of chronic spinal cord compression in the thoracic region may be accelerated by adverse stresses acting on the spinal cord associated with tethering of the spinal cord.

CONCLUSION

In defining the pathogenesis of this form of spinal cord cavitation, these cases suggest that therapeutic approaches directed at resolving the process should not only include lyses of adhesions, but shunting procedures, which appear to be most efficacious when these procedures are performed at or cephalad to the level of original tumor removal.

Induction of apoptotic cell death by DNA topoisomerase II inhibitors

We have analyzed the interference of antitumoral drugs acting through the inhibition of DNA topoisomerase II on the human HeLa cell metabolism. Different compounds characterized by a diverse mechanism of action have been used, namely m-amsacrine, an intercalative drug, etoposide, which does not intercalate DNA, and suramin, which exerts its effect through an unknown mechanism. In HeLa cells treated with increasing doses of these drugs, we have examined cell viability and DNA synthesis capacity, and we have evaluated topoisomerase II activity. Cellular morphology and DNA integrity have been studied in order to characterize the mechanism of cell death. The results we have obtained clearly indicate that topoisomerase II poisons induce cell death by apoptosis. These observations suggest a role of the inhibition of topoisomerase II activity in the apoptotic program.

Analysis of phosphorylation level of DNA topoisomerase-ii-alpha and topoisomerase-ii-Beta in human hela-cells

We have studied the phosphorylation of DNA topoisomerases II in HeLa cells focusing on the beta isoform of the enzyme which is very difficult to analyze because of its instability. In proliferating cells, we observed that both the a and beta isozymes are labeled after cell incubation with (32)p. The phosphorylation of beta enzyme occurs to a low extent, thus reflecting the expression of topoisomerases II during cell cycle. In cells treated with etoposide, the activity of topoisomerase II is inhibited and the level of phosphorylation decreases, suggesting a possible cooperation between this modification and drug response.

Activation of poly(ADP-ribose)polymerase in apoptotic human cells

We have studied the effect of the chemotherapeutic drug VP-16 (etoposide) on the metabolism of HeLa cells by analysing different cellular parameters considered as markers of apoptosis. Typical features such as chromatin condensation and internucleosomal DNA cleavage are visible in HeLa cells exposed to VP-16. We investigated whether the appearance of small-sized DNA fragments could regulate the ADP-ribosylation process. To this purpose, we have analysed, by means of the activity gel technique; the structural and catalytical properties of poly(ADP-ribose)polymerase. In extracts from cells where etoposide-induced DNA fragmentation occurred, we have shown that the label of the autoribosylated form of the enzyme is greatly increased even if the amount of the protein remains constant. This phenomenon is completely abolished in cells preincubated with poly(ADP-ribose)polymerase inhibitor, 3-aminobenzamide. After VP-16 administration, we have observed that the level of NAD is not heavily decreased. It is widely agreed that zinc exerts an inhibitory effect on the endonuclease(s) responsible for the fragmentation of DNA during apoptosis. After incubation of cells with zinc/VP-16 we have found the occurrence of apoptotic parameters even in the absence of internucleosomal DNA cleavage. The inhibition of DNA fragmentation prevents the activation of poly(ADP-ribose)polymerase activity. These results indicate that the activation of the enzyme towards the automodification reaction is strictly dependent on the appearance of DNA internucleosomal fragments and could represent a way to control enzyme activity.