Tumor necrosis factor-α impairs oligodendroglial differentiation through a mitochondria-dependent process.

Mitochondrial defects, affecting parameters such as mitochondrial number and shape, levels of respiratory chain complex components and markers of oxidative stress, have been associated with the appearance and progression of multiple sclerosis. Nevertheless, mitochondrial physiology has never been monitored during oligodendrocyte progenitor cell (OPC) differentiation, especially in OPCs challenged with proinflammatory cytokines. Here, we show that tumor necrosis factor alpha (TNF-α) inhibits OPC differentiation, accompanied by altered mitochondrial calcium uptake, mitochondrial membrane potential, and respiratory complex I activity as well as increased reactive oxygen species production. Treatment with a mitochondrial uncoupler (FCCP) to mimic mitochondrial impairment also causes cells to accumulate at the progenitor stage. Interestingly, AMP-activated protein kinase (AMPK) levels increase during TNF-α exposure and inhibit OPC differentiation. Overall, our data indicate that TNF-α induces metabolic changes, driven by mitochondrial impairment and AMPK activation, leading to the inhibition of OPC differentiation.

Identification of PTEN at the ER and MAMs and its regulation of Ca(2+) signaling and apoptosis in a protein phosphatase-dependent manner.

The tumor suppressor activity of PTEN (phosphatase and tensin homolog deleted on chromosome 10) is thought to be largely attributable to its lipid phosphatase activity. PTEN dephosphorylates the lipid second messenger phosphatidylinositol 3,4,5-trisphosphate to directly antagonize the phosphoinositide 3-kinase-Akt pathway and prevent the activating phosphorylation of Akt. PTEN has also other proposed mechanisms of action, including a poorly characterized protein phosphatase activity, protein-protein interactions, as well as emerging functions in different compartment of the cells such as nucleus and mitochondria. We show here that a fraction of PTEN protein localizes to the endoplasmic reticulum (ER) and mitochondria-associated membranes (MAMs), signaling domains involved in calcium ((2+)) transfer from the ER to mitochondria and apoptosis induction. We demonstrate that PTEN silencing impairs ER Ca(2+) release, lowers cytosolic and mitochondrial Ca(2+) transients and decreases cellular sensitivity to Ca(2+)-mediated apoptotic stimulation. Specific targeting of PTEN to the ER is sufficient to enhance ER-to-mitochondria Ca(2+) transfer and sensitivity to apoptosis. PTEN localization at the ER is further increased during Ca(2+)-dependent apoptosis induction. Importantly, PTEN interacts with the inositol 1,4,5-trisphosphate receptors (IP3Rs) and this correlates with the reduction in their phosphorylation and increased Ca(2+) release. We propose that ER-localized PTEN regulates Ca(2+) release from the ER in a protein phosphatase-dependent manner that counteracts Akt-mediated reduction in Ca(2+) release via IP3Rs. These findings provide new insights into the mechanisms and the extent of PTEN tumor-suppressive functions, highlighting new potential strategies for therapeutic intervention.

On the nonlinear threshold versus distance in long-haul highly-dispersive coherent systems.

We show that the accumulation rate of nonlinearity in highly-dispersive long-haul coherent links can also be measured from the nonlinear threshold decrease rate, and provide simulations of such rates for both single- and cross-channel effects. We then show how the estimated rate can be used for the overall system design.

Selective modulation of subtype III IP3R by Akt regulates ER Ca²âº release and apoptosis.

Ca²âº transfer from endoplasmic reticulum (ER) to mitochondria can trigger apoptotic pathways by inducing release of mitochondrial pro-apoptotic factors. Three different types of inositol 1,4,5-trisphosphate receptor (IP3R) serve to discharge Ca²âº from ER, but possess some peculiarities, especially in apoptosis induction. The anti-apoptotic protein Akt can phosphorylate all IP3R isoforms and protect cells from apoptosis, reducing ER Ca²âº release. However, it has not been elucidated which IP3R subtypes mediate these effects. Here, we show that Akt activation in COS7 cells, which lack of IP3R I, strongly suppresses IP3-mediated Ca²âº release and apoptosis. Conversely, in SH-SY 5Y cells, which are type III-deficient, Akt is unable to modulate ER Ca²âº flux, losing its anti-apoptotic activity. In SH-SY 5Y-expressing subtype III, Akt recovers its protective function on cell death, by reduction of Ca²âº release. Moreover, regulating Ca²âº flux to mitochondria, Akt maintains the mitochondrial integrity and delays the trigger of apoptosis, in a type III-dependent mechanism. These results demonstrate a specific activity of Akt on IP3R III, leading to diminished Ca²âº transfer to mitochondria and protection from apoptosis, suggesting an additional level of cell death regulation mediated by Akt.

Modeling nonlinearity in coherent transmissions with dominant intrachannel-four-wave-mixing.

By extending a well-established time-domain perturbation approach to dual-polarization propagation, we provide an analytical framework to predict the nonlinear interference (NLI) variance, i.e., the variance induced by nonlinearity on the sampled field, and the nonlinear threshold (NLT) in coherent transmissions with dominant intrachannel-four-wave-mixing (IFWM). Such a framework applies to non dispersion managed (NDM) very long-haul coherent optical systems at nowadays typical baudrates of tens of Gigabaud, as well as to dispersion-managed (DM) systems at even higher baudrates, whenever IFWM is not removed by nonlinear equalization and is thus the dominant nonlinearity. The NLI variance formula has two fitting parameters which can be calibrated from simulations. From the NLI variance formula, analytical expressions of the NLT for both DM and NDM systems are derived and checked against recent NLT Monte-Carlo simulations.

PDM-iRZ-QPSK vs. PS-QPSK at 100 Gbit/s over dispersion-managed links.

We compare by simulation the performance of 100 Gbit/s PDM-iRZ-QPSK and PS-QPSK transmission both in homogeneous and hybrid QPSK/OOK DM links. We detail the reasons of the overall performance investigating each nonlinear effect (SPM, XPM and XPolM) individually. Moreover, we compare the accuracy of the noise loading method with the more realistic use of noisy in-line amplifiers. Results shows that i) PDM-iRZ-QPSK and PS-QPSK have same reach in both homogeneous and hybrid setups, ii) correct simulations must include distributed ASE.

VDAC1 selectively transfers apoptotic Ca2+ signals to mitochondria.

Voltage-dependent anion channels (VDACs) are expressed in three isoforms, with common channeling properties and different roles in cell survival. We show that VDAC1 silencing potentiates apoptotic challenges, whereas VDAC2 has the opposite effect. Although all three VDAC isoforms are equivalent in allowing mitochondrial Ca(2+) loading upon agonist stimulation, VDAC1 silencing selectively impairs the transfer of the low-amplitude apoptotic Ca(2+) signals. Co-immunoprecipitation experiments show that VDAC1, but not VDAC2 and VDAC3, forms complexes with IP(3) receptors, an interaction that is further strengthened by apoptotic stimuli. These data highlight a non-redundant molecular route for transferring Ca(2+) signals to mitochondria in apoptosis.

Predictive value of hematological and phenotypical parameters on postchemotherapy leukocyte recovery.

BACKGROUND: Grade IV chemotherapy toxicity is defined as absolute neutrophil count <500/microL. The nadir is considered as the lowest neutrophil number following chemotherapy, and generally is not expected before the 7th day from the start of chemotherapy. The usual prophylactic dose of rHu-G-CSF (Filgrastim) is 300 microg/day, starting 24-48 h after chemotherapy until hematological recovery. However, individual patient response is largely variable, so that rHu-G-CSF doses can be different. The aim of this study was to verify if peripheral blood automated flow cytochemistry and flow cytometry analysis may be helpful in predicting the individual response and saving rHu-G-CSF. METHODS: During Grade IV neutropenia, blood counts from 30 cancer patients were analyzed daily by ADVIA 120 automated flow cytochemistry analyzer and by Facscalibur flow cytometer till the nadir. "Large unstained cells" (LUCs), myeloperoxidase index (MPXI), blasts, and various cell subpopulations in the peripheral blood were studied. At nadir rHu-G-CSF was started and 81 chemotherapy cycles were analyzed. Cycles were stratified according to their number and to two dose-levels of rHuG-CSF needed to recovery (300-600 vs. 900-1200 microg) and analyzed in relation to mean values of MPXI and mean absolute number of LUCs in the nadir phase. The linear regressions of LUCs % over time in relation to two dose-levels of rHu-G-CSF and uni-multivariate analysis of lymphocyte subpopulations, CD34(+) cells, MPXI, and blasts were also performed. RESULTS: In the nadir phase, the increase of MPXI above the upper limit of normality (>10; median 27.7), characterized a slow hematological recovery. MPXI levels were directly related to the cycle number and inversely related to the absolute number of LUCs and CD34(+)/CD45(+) cells. A faster hematological recovery was associated with a higher LUC increase per day (0.56% vs. 0.25%), higher blast (median 36.7/microL vs. 19.5/microL) and CD34(+)/CD45(+) cell (median 2.2/microL vs. 0.82/microL) counts. CONCLUSIONS: Our study showed that some biological indicators such as MPXI, LUCs, blasts, and CD34(+)/CD45(+) cells may be of clinical relevance in predicting individual hematological response to rHu-G-CSF. Special attention should be paid when nadir MPXI exceeds the upper limit of normality because the hematological recovery may be delayed.

Predictors of survival and toxicity in patients on adjuvant therapy with 5-fluorouracil for colorectal cancer.

The present study aimed at investigating whether the simultaneous evaluation of pharmacokinetic, pharmacogenetic and demographic factors could improve prediction on toxicity and survival in colorectal cancer patients treated with adjuvant 5-fluorouracil (5FU)/leucovorin therapy. One hundred and thirty consecutive, B2 and C Duke's stage colorectal cancer patients were prospectively enrolled. 5FU pharmacokinetics was evaluated at the first cycle. Thymidylate synthase (TYMS) 5'UTR and 3'UTR polymorphisms and methylenetetrahydrofolate reductase (MTHFR) C677T and A1298C polymorphisms were assessed in peripheral leukocytes. Univariate and multivariate analyses were applied to evaluate which variables could predict chemotherapy-induced toxicity, disease-free survival (DFS) and overall survival (OS). Multivariate analysis showed that: (a) low 5FU clearance was an independent predictive factor for severe toxicity (OR=7.32; P<0.0001); (b) high-5FU clearance predicted poorer DFS (HR=1.96; P=0.041) and OS (HR=3.37; P=0.011); (c) advanced age was associated with shorter DFS (HR=3.34; P=0.0008) and OS (HR=2.66; P=0.024); (d) the C/C genotype of the MTHFR C677T polymorphism was protective against grade 3-4 toxicity (P=0.040); (e) none of the TYMS polymorphisms could explain 5FU toxicity or clinical outcome.

Pharmacokinetic and demographic markers of 5-fluorouracil toxicity in 181 patients on adjuvant therapy for colorectal cancer.

BACKGROUND: The relationship between 5-fluorouracil (5-FU) pharmacokinetics and toxicity following i.v. bolus administration has not been extensively studied. PATIENTS AND METHODS: One hundred and eighty-one patients on adjuvant therapy with 5-FU plus leucovorin for colorectal cancer were the study population. 5-FU pharmacokinetics was determined on day 2 of the first, third, and fifth cycles; type and the grade of adverse reactions were recorded on the next cycle. RESULTS: The 5-FU area under the curve (AUC) measured at the first cycle ranged between 146 and 1236 mg x min/l and was significantly correlated with drug dose, patients' body weight (BW) and gender, females having higher AUCs. These covariates explained only 23% of AUC variability. AUC and age were the only covariates which discriminated between toxic (grade > or =2) and nontoxic cycles (grade <2), with an optimal AUC cut-off value of 596 mg x min/l. Such a correlation was lost during the next cycles following dose reduction because of toxicity in 80 patients. CONCLUSIONS: A method for calculating the initial 5-FU dose is proposed which takes into account patient BW, gender and a target AUC of 596 mg x min/l. Nevertheless, it appears that a substantial part of 5-FU toxicity is not linked to pharmacokinetic factors and dose adjustments must still be on the basis of careful clinical surveillance.

Increased myeloperoxidase index and large unstained cell values can predict the neutropenia phase of cancer patients treated with standard dose chemotherapy.

OBJECTIVE: The objective of this study was to better understand neutropenia induced by standard dose chemotherapy and to verify if there are any hematological parameters for defining the phase and possibly the duration of neutropenia. METHODS: The kinetics of large unstained cells (LUCs) and lymphocytes was evaluated in 324 blood counts of 56 chemotherapy cycles through the use of a Technicon H2 or an ADVIA 120 hematology analyzer. Blood samples collected during the neutropenia phase were also studied by flow cytometry using a large panel of monoclonal antibodies. Parametric and nonparametric statistics were employed to compare the different variables analyzed. A linear regression between each variable before and after nadir and a simple linear correlation among the same variables in the neutropenic and recovery phase were performed. RESULTS: The percentage of LUCs reaches the higher value at nadir and the difference between the mean value of prenadir and nadir is statistically significant (P <.01). The number of LUCs increases during the pre and postnadir phase. Lymphocytes number appears stable in the prenadir phase. The MPXI index increases in the prenadir phase and falls at nadir and this difference is statistically significant(P <.01). LUCs are correlated with blasts and CD34+ cells in the pre and postnadir phase, with CD3+/CD4+ cells in the prenadir phase, and with CD2+/CD56+ in the postnadir phase. CONCLUSIONS: Our data have shown that the estimation of both percentage of LUCs and MPXI can predict the neutropenia phase and orient for its duration. The lymphocyte number may be regarded as a parameter of risk of fever after day 5 of chemotherapy and the number of blood CD34+ cells may be predicted by LUC count.

Clinical and laboratory evaluation of hyperlipemic and hypothyroid patients.

OBJECTIVE: To determine the frequency of hypothyroidism in a sample of hyperlipemic patients and evaluate clinical and laboratory factors indicative of thyropathy among them. METHODS: Fifty-one hyperlipemic patients, grouped according to an earlier or recent diagnosis of their thyroid function into euthyroid and hypothyroid, were evaluated with clinical and laboratory examinations of blood levels of free T4 and TSH (by radioimmunoassay). Patients were on average 46.8 +/- 11.7 years old, predominantly of the female sex (62.5 %); 31 % had a previous diagnosis of hypothyroidism and were under treatment with thyroxin. RESULTS: Fourteen three percent of patients analyzed had hypothyroidism, which had not been detected before. Differentiating attributes of the groups analyzed were: a predominance of females among the hypothyroid patients and a higher HDL serum concentration among those recently diagnosed. CONCLUSION: In the present study, new cases of hypothyroidism in hyperlipemic patients were a frequent occurrence, yet few clinical and laboratory data except tests evaluating free T4 and TSH in the blood indicated which patients had thyroid dysfunction.

Statistics of the Jones matrix of fibers affected by polarization mode dispersion.

We carry out a statistical characterization of Jones matrix eigenvalues and eigenmodes to gain deeper insight into recently proposed fiber models based on Jones matrix spectral decomposition. A set of linear dynamic equations for the Pauli coordinates of the Jones matrix is established. Using stochastic calculus, we determine the joint distribution of the retardation angle of the eigenmodes and, indirectly, their autocorrelation function. The correlation bandwidth of the eigenmodes is found to be radical2/3 that of the polarization mode dispersion vector. The results agree well with simulations performed with the standard retarded plate model.

Altered tissue electric properties in lung cancer patients as detected by bioelectric impedance vector analysis.

Modifications of body composition are frequent in cancer patients. Bioelectric impedance analysis can specifically detect changes in tissue electric properties, which may be associated with outcome. We evaluated the distribution of the impedance vectors from 63 adult male patients with lung cancer, stages IIIB (33 patients) and IV (30 patients), in supportive therapy. Body weight change over the previous 6 m.o. was the same in both groups (stable/increased 36% and decreased in 62%). Patients were compared with 56 healthy subjects matched for gender, age, and body mass index (25 kg/m2). Impedance measurements (standard tetrapolar electrode placement on the hand and foot) were made with 50-kHz alternating currents. The resistance and reactance of the vector components were standardized by the height of the subjects and were plotted as resistance/reactance graphs. The impedance vector distribution was the same in patients with either stage IIIB or IV cancer. The mean vector position differed significantly between cancer patients and control subjects (Hotelling T2 test, P < 0.01) because of a reduced reactance component (i.e., a smaller phase angle) with preserved resistance component in both cancer groups. Patients with a phase angle smaller than 4.5 degrees had a significantly shorter, i.e., 18 m.o., survival. Body weight loss was not significantly associated with survival. In conclusion, impedance vectors from lung cancer patients were characterized by a reduced reactance component. The altered tissue electric properties were more predictive than weight loss of prognosis.

Test of a new technique for the diagnosis of carpal tunnel syndrome.

Several new techniques for carpal tunnel syndrome diagnosis have been developed in the last few years. This work tests a technique that compares the distal motor latency of the median nerve to the second lumbrical muscle (2L) with the distal motor latency of the ulnar nerve to the interossei muscle (INT). Results from 40 normal hands give the superior limit of the normal difference (2L-INT) as 0. 26 ms (&xmacr;+3 SD). In 55 hands with different levels of carpal tunnel syndrome, this new technique was more sensitive and accurate than the conventional test which uses the distal motor latency of the median nerve to the abductor pollicis brevis muscle (APB), especially in the less severe cases. With the absence of the compound muscle action potentials of the APB muscle caused by severe thenar atrophy, it is much easier to obtain the potential from the 2L muscle. We concluded that this is a sensitive, simple, rapid, and non-invasive new technique, and therefore, it should be incorporated as part of the routine ENMG procedures for carpal tunnel syndrome diagnosis.

Quantitative analysis of ribonucleoside triphosphates in human lymphoid cells by micellar electrokinetic capillary chromatography.

Micellar electrokinetic capillary chromatography (MECC) was applied to develop an analytical method for quantitation of ribonucleoside triphosphates (rNTPs) in human lymphoid cells obtained from patients with B-chronic lymphocytic leukaemia (B-CLL) and cutaneous lymphomas. The results of this analysis showed a significant depression of intracellular rNTPs in patients with B-CLL, compared with rNTPs of healthy controls. These data are in agreement with other studies in which rNTP separations were performed with traditional high-performance liquid chromatography. MECC has proved to be a useful tool for intracellular rNTPs determination, revealing possible new applications in the study of the metabolic state of human cells. In addition, this method can be useful in monitoring the effect of many drugs (antiviral, antineoplastic) which interfere with nucleotide metabolism.

Neuron-specific enolase, thymidine kinase, and tissue polypeptide-specific antigen in diagnosis and response to chemotherapy of small-cell lung cancer.

The clinical usefulness of neuron-specific enolase (NSE), thymidine kinase (TK), and tissue polypeptide-specific antigen (TPS) was investigated in 41 patients (53-80 years old) with recently discovered small-cell lung cancer (SCLC). Eleven patients exhibited limited disease (LD) and 30 extensive disease (ED). Serum samples for NSE, TPS (immunoradiometric assay), and TK (radioenzymatic assay) evaluations were drawn from all patients at the time of diagnosis and before each cycle of chemotherapy in the treated patients. Therapy consisted of i.v. carboplatin 300 mg/m2 on the first day and i.v. etoposide 120 mg/m2 from the first to the third day every 3 weeks. Nine patients refused or were not eligible for chemotherapy. Five patients received only one course and showed no response (NR); 9 patients received two courses; 18 patients received three or more courses. In the last group, complete remission (CR) was obtained in 9 cases, partial remission (PR) in 18 cases. The tumor markers studied did not show any significant difference in distinguishing LD from ED. NSE and TPS were significantly more often abnormal than TK, either at the time of diagnosis (p < 0.05) or in PR or NR patients (p < 0.05). In relation to chemotherapy response, NSE and TPS serum patterns were shown to be more reliable than TK in PR (p < 0.05) and NR patients (computed error between 10% and 15%). No significant difference was observed between serum NSE and TPS patterns. Serum NSE and TPS seem to be more useful in the diagnosis and follow-up of SCLC patients undergoing chemotherapy. Further trials are necessary to ascertain whether the associated assessment of NSE and TPS can add useful information to that provided by the assessment of NSE alone.

Primary carcinoma of fallopian tube: experience of six cases.

Between 1980 and 1993, six cases of primary carcinoma of the fallopian tube were diagnosed and treated at the Hospital of Rovigo. Median age was 64.6 years; the most frequent symptom was atypical vaginal bleeding; only one patient presented a history compatible with hydrops tubae profluens. No patient in this series had a correct preoperative diagnosis. In Papanicolau smears and endometrial currettage, one case was positive for cancer. Primary surgical treatment was performed in all cases, followed by adjuvant chemotherapy. Histologic differentiation was Grade 2 in three patients and Grade 3 in three patients. Staging was by a system analogous to the FIGO classification for ovarian carcinoma. Two patients had Stage I disease; one, Stage II; two, Stage III; and one, Stage IV. Two patients died 14 and 37 months after the initial diagnosis. Three patients without clinical evidence of disease underwent second look procedures; the patients were alive and disease free with follow up ranging from 45 to 55 months. One patient is alive 4 months after surgery. In this series survival was not associated with grade, but was dependent upon stage. In our study, the prognostic value of the second- and third-look procedures are discussed.

[Screening with latex IgM reagent on umbilical cord blood for demonstration of intrauterine infections]. / Screening con reattivo al latex IgM su sangue funicolare per evidenziare infezioni intrauterine.

The AA. have found IgM in cord sera of 903 newborns. In 13 (1.44%) there was an increase of IgM and the control made on neonatal serum within the first 5 days from birth has shown a positive result only in 1 case (7.69% of positives). The AA. present, in the conclusions, some considerations that justify the results of their work.