Association of free-living physical activity measures with metabolic phenotypes in type 2 diabetes at the time of diagnosis. The Verona Newly Diagnosed Type 2 Diabetes Study (VNDS).

BACKGROUND AND AIM: Lifestyle is considered a major determinant of risk of type 2 diabetes (T2D). We investigated whether daily physical activity (DPA) is associated with beta-cell function (BF) and/or insulin sensitivity (IS) in patients with T2D at the time of diagnosis. METHODS AND RESULTS: In 41 subjects enrolled in the Verona Newly-Diagnosed Type 2 Diabetes Study we assessed: (1) IS, by euglycaemic insulin clamp; (2) BF, estimated by prolonged-OGTT minimal modeling and expressed as derivative and proportional control; (3) DPA and energy expenditure (EE), assessed over 48-h monitoring by a validated wearable armband system. Study participants (median [IQR]; age: 62 [53-67] years, BMI: 30.8 [26.5-34.3] Kg m-2, HbA1c: 6.7 [6.3-7.3]%; 49.7 [45.4-56.3] mmol/mol) were moderately active (footsteps/day: 7773 [5748-10,927]; DPA≥3MET: 70 [38-125] min/day), but none of them exercised above 6 metabolic equivalents (MET). EE, expressed as EETOT (total daily-EE) and EE≥3MET (EE due to DPA≥3MET) were 2398 [2226-2801] and 364 [238-617] Kcal/day, respectively. IS (M-clamp 630 [371-878] µmol/min/m2) was positively associated with DPA and EE, independent of age, sex and BMI (p < 0.05). Among the DPA and EE parameters assessed, DPA≥3MET and EETOT were independent predictors of IS in multivariable regression analyses, adjusted for age, sex, BMI (R2 = 16%, R2 = 19%, respectively; p < 0.01). None of model-derived components of BF was significantly associated with DPA or accompanying EE. CONCLUSIONS: Our study highlighted moderate levels of DPA and total EE as potential determinants of IS, but not BF, in T2D at the time of diagnosis. Intervention studies are needed to conclusively elucidate the effect of DPA on these features. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. UNIQUE IDENTIFIER: NCT01526720.

Effects of aerobic or resistance exercise training on cardiovascular autonomic function of subjects with type 2 diabetes: A pilot study.

BACKGROUND AND AIMS: Both aerobic (AER) and resistance (RES) training improve metabolic control in patients with type 2 diabetes (T2DM). However, information on the effects of these training modalities on cardiovascular autonomic control is limited. Our aim was to compare the effects of AER and RES training on cardiovascular autonomic function in these subjects. METHODS AND RESULTS: Cardiovascular autonomic control was assessed by Power Spectral Analysis (PSA) of Heart Rate Variability (HRV) and baroreceptors function indexes in 30 subjects with T2DM, randomly assigned to aerobic or resistance training for 4 months. In particular, PSA of HRV measured the Low Frequency (LF) and High Frequency (HF) bands of RR variations, expression of prevalent sympathetic and parasympathetic drive, respectively. Furthermore, we measured the correlation occurring between systolic blood pressure and heart rate during a standardized Valsalva maneuver using two indexes, b2 and b4, considered an expression of baroreceptor sensitivity and peripheral vasoactive adaptations during predominant sympathetic and parasympathetic drive, respectively. After training, the LF/HF ratio, which summarizes the sympatho-vagal balance in HRV control, was similarly decreased in the AER and RES groups. After AER, b2 and b4 significantly improved. After RES, changes of b2 were of borderline significance, whereas changes of b4 did not reach statistical significance. However, comparison of changes in baroreceptor sensitivity indexes between groups did not show statistically significant differences. CONCLUSION: Both aerobic and resistance training improve several indices of the autonomic control of the cardiovascular system in patients with T2DM. Although these improvements seem to occur to a similar extent in both training modalities, some differences cannot be ruled out. CLINICAL TRIAL REGISTRATION NUMBER: NCT01182948, clinicaltrials.gov.

Cryptic and rare Aspergillus species in Brazil: prevalence in clinical samples and in vitro susceptibility to triazoles.

Aspergillus spp. are among the most common causes of opportunistic invasive fungal infections in tertiary care hospitals. Little is known about the prevalence and in vitro susceptibility of Aspergillus species in Latin America, because there are few medical centers able to perform accurate identification at the species level. The purpose of this study was to analyze the distribution of cryptic and rare Aspergillus species among clinical samples from 133 patients with suspected aspergillosis admitted in 12 medical centers in Brazil and to analyze the in vitro activity of different antifungal drugs. The identification of Aspergillus species was performed based on a polyphasic approach, as well as sequencing analysis of the internal transcribed spacer (ITS) region, calmodulin, and ß-tubulin genes and phylogenetic analysis when necessary. The in vitro susceptibility tests with voriconazole, posaconazole, and itraconazole were performed according to the CLSI M38-A2 document (2008). We demonstrated a high prevalence of cryptic species causing human infection. Only three isolates, representing the species Aspergillus thermomutatus, A. ochraceus, and A. calidoustus, showed less in vitro susceptibility to at least one of the triazoles tested. Accurate identifications of Aspergillus at the species level and with in vitro susceptibility tests are important because some species may present unique resistance patterns against specific antifungal drugs.

Glomerular filtration rate, albuminuria and risk of cardiovascular and all-cause mortality in type 2 diabetic individuals.

BACKGROUND AND AIMS: To assess all-cause and cardiovascular mortality in type 2 diabetic individuals according to estimated glomerular filtration rate (eGFR) and albuminuria. METHODS AND RESULTS: We followed 2823 type 2 diabetic outpatients for a median period of 6 years for the occurrence of all-cause and cardiovascular mortality. eGFR was estimated using the abbreviated Modification of Diet in Renal Disease study equation. At baseline, an eGFR < 60 ml/min/1.73 m² and abnormal albuminuria were present in 22.5% and 26.0% of participants, respectively. During follow-up, a total of 309 patients died, 53% of deaths were secondary to cardiovascular causes. Risks of all-cause and cardiovascular mortality increased progressively with decreasing eGFR and increasing albuminuria. After adjustment for age, sex, body mass index, smoking, hypertension, diabetes duration, hemoglobin A1c, plasma lipids, medications use (hypoglycemic, anti-hypertensive, anti-platelet or lipid-lowering drugs) and albuminuria, the hazard ratios of all-cause and cardiovascular mortality per 1-SD decrease in eGFR were 1.53 (95%CI 1.2-2.0; p < 0.0001) and 1.51 (95%CI 1.05-2.2; p=0.023), respectively. A similar pattern in the risk of all-cause and cardiovascular mortality was seen for albuminuria (1.14, 1.01-1.3, p=0.028 and 1.19, 1.01-1.4, p=0.043 per 1-SD increase in albuminuria, respectively) after adjustment for eGFR and other potential confounders. CONCLUSIONS: These findings suggest that both decreasing eGFR and rising albuminuria are associated with all-cause and cardiovascular mortality in type 2 diabetic individuals, independently of traditional risk factors and diabetes-related variables.

Embutidos cocidos funcionales / Functional cooked sausage-type product

Se ha optimizado, desde el punto de vista funcional, un embutido cocido, útil para prevenir la aterosclerosis, usando aceites vegetales con alto contenido en ácidos grasos poliinsaturados.El producto obtenido a nivel artesanal y posteriormente a nivel industrial con el apoyo de importante frigorífico, no posee grasas animales adicionadas, no contiene ácidos grasos trans, tiene bajo contenido en sodio, es bajo en calorías, no presenta cambios organolépticos considerables con relación a productos similares de primeras marcas, y esta enriquecido con AGPIw3 obteniéndose una relación w6:w3 ideal.

Familial adenomatous polyposis. Surgical treatment: when and how.

Familial adenomatous polyposis is an autosomal dominated inherited disease, caused by the mutation of the tumour suppressor gene adenomatous polyposis coli on chromosome 5. Despite being a rare disorder, accounting for some 1% of colorectal cancers, it represents an interesting model of hereditary disease, because of its intrinsic characteristics, conventionally defined by the presence of more than 100 colorectal polyps, as well as extra-colon manifestations, the attenuated form of the disease, genetic aspects, the inevitable progression to colorectal cancer and hence the correct therapy to treat or prevent the fatal evolution of the disease. Surgical treatment is based above all on two techniques: ileorectal anastomosis, which requires careful surveillance of rectal remnant, and ileal pouch-anal anastomosis, which totally eradicates the disease. The suitability of using these two techniques is discussed in view of new genetic and clinical findings, acquired from personal experience and from the literature.

Effects of topoisomerase II inhibitors on gastric cancer cells characterized by different genetic lesions.

Gastric cancer is poorly-responsive to widely used antitumour drugs, the efficacy of which is thought to be related to the capacity of triggering apoptosis. This process requires a series of gene products including a functional p53 protein. We tested the effects of two DNA topoisomerase II poisons, etoposide and doxorubicin, on gastric cancer cell lines with different genetic lesions. We characterised MKN74 and MKN28 cells for p53 gene status and for the expression of p53 and p21 proteins, as well as of topoisomerase II alpha and beta isoforms. After drug treatments, the cells were analysed for drug cytotoxicity, colony forming ability, cell cycle distribution and presence of apoptotic features. Our findings demonstrated that both etoposide and doxorubicin have a potent anti-proliferative effect on gastric cancer cells. Cell death kinetics was different in the two cell lines, MKN74 cells being more sensitive than MKN28 to the drugs. MKN74 cells, although harboring a wt p53 gene, were unable to undergo a massive apoptosis following etoposide treatment. The response of this cell line might be related to the topoisomerase II beta isozyme, the expression of which proved to be undetectable.

Different effects of methotrexate on DNA mismatch repair proficient and deficient cells.

Antifolates exert their antiproliferative activity through the inhibition of dihydrofolate reductase and, as a consequence, of thymidylate synthesis, thereby inducing nucleotide misincorporation and impairment of DNA synthesis. We investigated the processes involved in the repair of antifolate-induced damage and their relationship with cell death. Since misincorporated bases may be removed by DNA mismatch repair (MMR), the study was carried out on the MMR-proficient human cell lines HeLa and HCT116+chr3, and, in parallel, on the MMR-deficient cell lines HeLa cell-clone12, defective in the protein hPMS2, and HCT116, with an inactive hMLH1. After treatment with methotrexate (MTX), we observed that DNA repair synthesis occurs independently of the cellular MMR function. Clear signs of apoptosis such as nuclear shrinkage, chromatin condensation and degradation, DNA laddering, and poly (ADP-ribose) polymerase (PARP) proteolysis, were visible in both MMR(+) and MMR(-) cells. Remarkably, cell viability was lower and the apoptotic process was triggered more efficiently in the MMR-competent cells.

Functional uncoupling of adenosine A(2A) receptors and reduced responseto caffeine in mice lacking dopamine D2 receptors.

Dopamine D(2) receptors (Rs) and adenosine A(2A)Rs are coexpressed on striatopallidal neurons, where they mediate opposing actions. In agreement with the idea that D(2)Rs tonically inhibit GABA release from these neurons, stimulation-evoked GABA release was significantly greater from striatal/pallidal slices from D(2)R null mutant (D(2)R(-/-)) than from wild-type (D(2)R(+/+)) mice. Release from heterozygous (D(2)R(+/-)) slices was intermediate. However, contrary to predictions that A(2A)R effects would be enhanced in D(2)R-deficient mice, the A(2A)R agonist CGS 21680 significantly increased GABA release only from D(2)R(+/+) slices. CGS 21680 modulation was observed when D(2)Rs were antagonized by raclopride, suggesting that an acute absence of D(2)Rs cannot explain the results. The lack of CGS 21680 modulation in the D(2)R-deficient mice was also not caused by a compensatory downregulation of A(2A)Rs in the striatum or globus pallidus. However, CGS 21680 significantly stimulated cAMP production only in D(2)R(+/+) striatal/pallidal slices. This functional uncoupling of A(2A)Rs in the D(2)R-deficient mice was not explained by reduced expression of G(s), G(olf), or type VI adenylyl cyclase. Locomotor activity induced by the adenosine receptor antagonist caffeine was significantly less pronounced in D(2)R(-/-) mice than in D(2)R(+/+) and D(2)R(+/-) mice, further supporting the idea that D(2)Rs are required for caffeine activation. Caffeine increased c-fos only in D(2)R(-/-) globus pallidus. The present results show that a targeted disruption of the D(2)R reduces coupling of A(2A)Rs on striatopallidal neurons and thereby responses to drugs that act on adenosine receptors. They also reinforce the ideas that D(2)Rs and A(2A)Rs are functionally opposed and that D(2)R-mediated effects normally predominate.

Metformin effects on clinical features, endocrine and metabolic profiles, and insulin sensitivity in polycystic ovary syndrome: a randomized, double-blind, placebo-controlled 6-month trial, followed by open, long-term clinical evaluation.

In the last few years some studies assessed the effects of attenuation of hyperinsulinemia and insulin resistance, obtained by insulin sensitizing agents, in women with polycystic ovary syndrome (PCOS), suggesting potential scope for these drugs in treating the whole spectrum of reproductive, endocrine, and metabolic abnormalities found in such subjects. However, the results of these studies, mostly uncontrolled and short-term, are still inconclusive, and there is no long-term follow-up. In the present study, 23 PCOS subjects [mean (+/- SE) body mass index 30.0+/-1.1 kg/m2] were randomly assigned to double-blind treatment with metformin (500 mg tid) or placebo for 6 months, while maintaining their usual eating habits. Before and after treatment, menstrual history, endocrine and metabolic profiles, serum 17-hydroxyprogesterone response to GnRH-agonist testing, and insulin sensitivity measured by the glucose clamp technique were assessed. Eighteen of these women, as well as 14 additional PCOS patients, were subsequently given metformin in an open trial for 11.0+/-1.3 months (range 4-26), to assess long-term effects of treatment and baseline predictors of metformin efficacy on reproductive abnormalities. After metformin treatment, mean frequency of menstruation improved (P = 0.002), due to striking amelioration of menstrual abnormalities in about 50% of subjects. Women given metformin showed reduced plasma insulin (at fasting: P = 0.057; during the clamp studies: P<0.01) and increased insulin sensitivity (P<0.05). Concurrently, ovarian hyperandrogenism was attenuated, as indicated by significant reductions in serum free testosterone (P<0.05) and in the 17-hydroxyprogesterone response to GnRH-agonist testing (P<0.05). No changes were found in the placebo group. Only comparable minor changes in body mass index were found both in the metformin group and in the placebo group. In the open, long-term trial 17 women (54.8%) showed striking improvements of their menstrual abnormalities and were considered as responders. Logistic regression analysis of baseline characteristics in responders and nonresponders showed that plasma insulin, serum androstenedione, and menstrual history were independent predictors of the treatment's clinical efficacy. In 10 subjects whose menses proved regular after treatment, the great majority of cycles became ovulatory (32 out of 39 assessed, 79%). In conclusion, in women with PCOS metformin treatment reduced hyperinsulinemia and hyperandrogenemia, independently of changes in body weight. In a large number of subjects these changes were associated with striking, sustained improvements in menstrual abnormalities and resumption of ovulation. Higher plasma insulin, lower serum androstenedione, and less severe menstrual abnormalities are baseline predictors of clinical response to metformin.

Antiandrogen drugs lower serum prostate-specific antigen (PSA) levels in hirsute subjects: evidence that serum PSA is a marker of androgen action in women.

Assay by ultrasensitive methods of serum prostate-specific antigen (PSA) recently demonstrated that many women have detectable levels of this molecule. Interestingly, serum PSA concentrations were higher in hirsute than in nonhirsute subjects, suggesting that, also in females, PSA may be regulated by androgens. To establish the potential for this assay as a biochemical marker of androgen action in women, we studied 40 hirsute subjects recruited in a double-blind, placebo-controlled, 6-month trial assessing the effects of 3 different antiandrogen drugs: spironolactone, flutamide, or finasteride. In each subject, serum PSA, free testosterone, and 3alpha-androstanediol glucuronide were determined at baseline and at the end of treatments. At baseline, PSA concentrations were higher in these 40 women than in 19 nonhirsute healthy controls (12.9+/-1.5 vs. 4.9+/-0.7 pg/mL, P = 0.03) and significantly correlated with serum free testosterone (r = 0.37, P<0.005). After treatments, the 29 hirsute subjects given active drugs showed significant reduction of serum PSA levels (7.2+/-1.4 vs. 14.7+/-3.0 pg/mL, P = 0.002). This phenomenon was correlated to baseline PSA values. No change was found in the placebo group. In conclusion, serum PSA is increased in many hirsute women. A 6-month course of antiandrogen treatments with spironolactone, flutamide, or finasteride determines a reduction of PSA levels in these subjects. These results suggest that serum PSA is a biochemical marker of androgen action in tissues of female subjects.

Comparison of spironolactone, flutamide, and finasteride efficacy in the treatment of hirsutism: a randomized, double blind, placebo-controlled trial.

To compare objectively the efficacies of spironolactone (100 mg/day), flutamide (250 mg/day), and finasteride (5 mg/day) in the treatment of hirsutism, 40 hirsute women were randomly assigned to double blind treatments with 1 of these 3 drugs or placebo for 6 months. Before and at the end of treatment, hirsutism was quantitatively measured in each subject by determination, by computer-assisted light microscopy, of the largest diameter of 5 hairs plucked from the linea alba. These measurements were averaged to produce a mean hair shaft diameter. For each subject, baseline and posttreatment assessments were carried out at the same time by an investigator blinded to both time and type of therapy. In addition, a semi-quantitative clinical evaluation was carried out by a modification of the Ferriman-Gallwey (F-G) scoring method, performed by a single investigator. At baseline the 4 groups of women had similar hair diameters and F-G scores. After 6 months of therapy all groups of subjects given active drugs showed reductions of their hair diameters, without statistically significant differences among groups (mean change +/- SEM, -11.7+/-5.6%, -18.0+/-6.1%, and -12.6+/-6.7%, respectively, in the spironolactone, flutamide, and finasteride groups). F-G scores were also significantly reduced in women receiving antiandrogen drugs, again without differences among groups (mean change, -41.0+/-5.5%, -38.9+/-7.2%, and -31.6+/-3.7%, respectively). No significant changes from baseline values were recorded by either hair diameter (-1.4+/-5.2%) or F-G score (+5.4+/-3.7%) assessment in the placebo group. In conclusion, spironolactone, flutamide, and finasteride are all effective in the treatment of hirsutism. After a 6-month course of therapy, the clinical efficacies of these drugs, at least at the doses used, are similar.

Spironolactone, but not flutamide, administration prevents bone loss in hyperandrogenic women treated with gonadotropin-releasing hormone agonist.

GnRH agonists (GnRHa) have recently been proposed for the treatment of hirsutism in women with the polycystic ovary syndrome (PCOS). As most of these subjects have increased androgen secretion from both ovaries and adrenal glands, the association of GnRHa with antiandrogen drugs might enhance the clinical response to treatment. On the other hand, this association might also potentiate the adverse effects of GnRHa on bone metabolism, generating a potentially harmful situation at the skeletal level. In this study we investigated in 41 PCOS patients the skeletal effects of a 6-month course of GnRHa (tryptorelin, 3.75 mg, i.m., monthly), either alone (n = 12) or associated with the antiandrogen drugs spironolactone (100 mg, orally, once daily; n = 14) or flutamide (250 mg, once daily; n = 15). In all subjects bone mineral density was measured before and after treatment by dual energy x-ray absorptiometry at the lumbar spine (L2-L4) and at the femoral neck and Ward's triangle. In addition, at baseline and after 6 months of therapy, bone metabolism markers (serum and urinary calcium, serum phosphorus and alkaline phosphatase, plasma osteocalcin, and urinary hydroxyproline) and endocrine parameters (serum gonadotropins, estradiol, and free testosterone) were assayed. Women given either GnRHa alone or associated with spironolactone or flutamide were similar for age and body mass index. At baseline, the 3 groups of PCOS women were also similar for endocrine and bone parameters. After 6 months, all treatments determined similar striking suppressions of serum gonadotropins and sex steroids. Concurrently, bone mineral density was significantly reduced at all examined sites in subjects receiving either GnRHa alone or GnRHa plus flutamide. Conversely, women given GnRHa plus spironolactone did not show any change in skeletal mass from baseline values (P < 0.05-0.01 among groups). Biochemical parameters of bone metabolism were consistent with densitometric assessments. In conclusion, after a 6-month course of therapy, bone mineral density is reduced in PCOS women given either GnRHa alone or GnRHa plus flutamide, but not in those receiving GnRHa plus spironolactone. The mechanisms of the bone-sparing effect of spironolactone remain to be determined. Nevertheless, this drug could represent a useful tool to prevent skeletal loss in women given GnRHa as well as in other hypoestrogenic conditions, in particular when estrogens are not recommended.

Differential involvement of DNases in HeLa cell apoptosis induced by etoposide and long term-culture.

We have applied to human HeLa cells two different stimuli of apoptosis: the antitumoral drug etoposide, and a more 'physiological' death condition, obtained by growing cells in the same medium for long time periods, for up to 10 days. Analysis of different parameters demonstrated that in both experimental systems the same apoptotic features are visible. However, the DNA degradation pattern appeared to be different, suggesting the involvement of different DNases. In this view, we have analyzed the activity and expression of Ca2+-Mg2+-dependent and acid DNases. We have observed that DNase I is not modulated during apoptosis. In contrast, the acid L-DNase II (derived from Leukocyte Elastase Inhibitor by post-translational modification), recently identified in our laboratory, is mainly active in the apoptotic pathway induced by long term-culture. Furthermore, we have provided evidence that while caspase 3 is activated by both inducers, caspase 1 is essential only for the etoposide-induced apoptosis.

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.

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.

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.

Acute effect of insulin on autonomic regulation of the cardiovascular system: a study by heart rate spectral analysis.

Insulin is suggested to have direct effects on the cardiovascular system but these are not well described. We assessed the possible influence of insulin on autonomic control of heart function. A 2-h hyperinsulinaemic euglycaemic clamp was performed in 10 healthy women (mean age 21.7 +/- 1.3 years), at two different insulin infusion rates: 80 mU m-2 and 400 mU m-2 min-1, in 7 and 3 subjects, respectively. Saline alone was infused in 4 controls. Power spectral analysis (PSA) of heart rate was recorded before and after 90-120 min of insulin infusion, as were blood pressure and heart rate. Although there were no significant changes in heart rate or blood pressure, PSA showed marked reductions of high frequency (HF) bands after insulin (2.60 +/- 0.12 vs 2.09 +/- 0.16 log ms2, p < 0.005), as at both low and high infusion rates (2.46 +/- 0.13 to 2.14 +/- 0.23 log ms2, p < 0.05, and 2.92 +/- 0.18 to 1.98 +/- 0.06 log ms2, p < 0.01, respectively). There were no significant changes of low frequency (LF) bands. Densities at LF and HF did not change significantly in control studies. As HF and LF are considered to reflect parasympathetic and mainly sympathetic control respectively, our observation of an increased LF/HF ratio (0.13 +/- 0.10 vs 0.63 +/- 0.13, p < 0.005) may be considered an index of relative sympathetic predominance induced by insulin infusion. We conclude that insulin affects the cardiovascular system, reducing vagal influence on the heart and inducing a relative hypersympathetic tone.

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.