The Fokker-Planck equation of the superstatistical fractional Brownian motion with application to passive tracers inside cytoplasm.

By collecting from literature data experimental evidence of anomalous diffusion of passive tracers inside cytoplasm, and in particular of subdiffusion of mRNA molecules inside live Escherichia coli cells, we obtain the probability density function of molecules' displacement and we derive the corresponding Fokker-Planck equation. Molecules' distribution emerges to be related to the Krätzel function and its Fokker-Planck equation to be a fractional diffusion equation in the Erdélyi-Kober sense. The irreducibility of the derived Fokker-Planck equation to those of other literature models is also discussed.

Generalized Cattaneo (telegrapher's) equations in modeling anomalous diffusion phenomena.

We study generalized Cattaneo (telegrapher's) equations involving memory effects introduced by smearing the time derivatives. Consistency conditions where the smearing functions obey restrict freedom in their choice but the proposed scheme goes beyond the approach based on using fractional derivatives. We find conditions under which solutions of the equations considered so far can be recognized as probability distributions, i.e., are normalizable and nonnegative on their domains. Nonnegativity of solutions is demonstrated by methods of positive definite and completely monotonic functions with the Bernstein theorem being the cornerstone of the ongoing proofs. Analysis of exactly solvable examples and relevant mean-squared displacements enables us to classify diffusion processes described by such got solutions and to identify them with either ordinary or anomalous diffusion which character may change over time. To complete the present research we compare our results with those obtained using the continuous-time random-walk and the continuous-time persistent random-walk approaches.

Fas receptor is not present on ejaculated human sperm.

BACKGROUND: Apoptosis appears to have an essential role in the control of testis germ cell number and Fas expression has been reported in apoptotic spermatocytes and spermatids. We investigated if Fas (CD95) was present on ejaculated human sperm and any relationship between Fas on sperm and the apoptotic marker Syto16. METHODS: Semen samples from 77 male partners of infertile couples were evaluated. Each sample was analysed both before and after semen preparation by conventional microscopical procedures and by flow cytometry (FC). A multiparameter FC analysis to assess simultaneously sperm concentration, sperm viability, sperm apoptosis, CD45 positive (leukocyte) and CD95 (Fas) positive cell concentration was carried out. A further 10 samples were studied by indirect immunofluorescence to confirm results. RESULTS: The mean concentration of CD95 positive cells was very low (<1%), with no significant difference between normozoospermic and non-normozoospermic men. There was no correlation between apoptotic sperm and CD95 positive cell concentration. A linear correlation was found between CD95 positive cell and leukocyte (CD45 positive) concentration (r = 0.9946, P < 0.0001). CD95 mean fluorescence intensity of leukocytes was 10-fold greater than that of sperm and of isotypic control. Both incubation with activating anti-Fas antibody and betulinic acid induced apoptosis in leukocytes. Incubation with betulinic acid, but not with activating anti-Fas antibody, induced apoptosis in sperm. Pre-incubation with neutralizing anti-Fas antibody suppressed CD95 expression on leukocytes, whereas it did not change sperm CD95 peak fluorescence. CONCLUSIONS: There is no detectable quantity of Fas on human ejaculated sperm.

Influence of Eulerian and Lagrangian scales on the relative dispersion properties in Lagrangian stochastic models of turbulence.

The influence of Eulerian and Lagrangian scales on the turbulent relative dispersion is investigated through a three-dimensional Eulerian consistent Lagrangian stochastic model. As a general property of this class of models, it is found to depend solely on a parameter beta based on the Kolmogorov constants C(K) and C0. This parameter represents the ratio between the Lagrangian and Eulerian scales and is related to the intrinsic inhomogeneity of the relative dispersion process. In particular, the quantity g*=g/C(0) (where g is the Richardson constant) and the temporal extension of the t(3) regime are found to be strongly dependent on the value adopted for beta.

Modulation of anthracycline activity in canine mammary tumour cells in vitro by medroxyprogesterone acetate.

Failure of chemotherapy with anthracyclines as a result of drug resistance and toxicity is a major problem in the clinical management of neoplasia. The aim of the present study was to evaluate the activity of medroxyprogesterone acetate (MPA) as a chemosensitiser on anthracycline cytotoxicity. The study investigated whether such an effect could be related to an increase in lipid peroxidation, nitric oxide production, membrane fluidity and intracellular anthracycline concentration. The results showed that anthracyclines decreased nitric oxide production but increased membrane viscosity (polarisation constant) and lipid hydroperoxide formation in canine mammary tumour cells. Moreover, it was found that both drug-induced cytotoxicity and membrane viscosity increased in the presence of MPA. Conversely, lipid hydroperoxides decreased in MPA-supplemented cells. Medroxyprogesterone acetate did not show any effect on nitric oxide production. The two anthracyclines used (doxorubicin and idarubicin) showed differential intranuclear accumulation in canine mammary tumour cells, and MPA significantly modified intracellular concentration of anthracyclines.

Medroxyprogesterone acetate increases anthracyclines uptake in chronic lymphatic leukemia cells: role of nitric oxide and lipid peroxidation.

Anthracyclines are one of the most used drugs in the therapy of several malignant tumors. Unfortunately, its use is still limited by their cardio-toxicity and by the presence of cancer cells resistant to these drugs. In the present study we evaluated the ability of a chemo-sensitizer agent, MPA (Medroxyprogesterone Acetate), to modify anthracyclines intranuclear uptake in normal leukocytes (NL) and in chronic lymphatic leukemia leukocytes (CLL). Moreover we evaluated the role of lipid peroxidation and nitric oxide (NO) production on antracyclines activity and on their combination with MPA. Our data show that MPA significantly increases anthracyclines uptake only in CLL cells and decreases anthracyclines induced lipid peroxidation.

Modification of membrane fluidity and depolarization by some anthracyclines in different cell lines.

One of the major problems in cancer treatment is the progressive desensitization of cancer cells to chemotherapeutic drugs. Several hypotheses have been advanced to explain this property of cancer cells. In recent years different calcium channel blockers and other chemosensitizing agents like synthetic progestins have been used to revert drug resistance. In our experiments we evaluated the effects of Doxorubicin and Idarubicin on membrane fluidity and depolarization using normal lymphocytes, chronic lymphatic leukemia lymphocytes, normal breast and hormone dependent breast cancer cells and cardiomyocytes. The drugs were used alone or in combination with Verapamil and Medroxyprogesterone acetate. We showed that MPA enhances DOXO and IDA biochemical effects, acting not only on the membrane lipid bilayer, but also on ion channels. VERA instead does not seem to act through the same mechanism.

Effect of cis-diamminedichloroplatinum (II) on rat thymocyte membrane potential.

The effect of cis-diamminedichloroplatinum (II) (cisDDP) on rat thymocytes has been investigated. Changes of anisotropy constant and depolarization of the cell membrane have been determined. The effect of cisDDP on the anisotropy constant has been observed on treated animal thymocytes but not on treated isolated cell membranes. CisDDP inhibits KCl-induced depolarization in isolated rat thymocytes. This inhibiting effect is still present at a concentration as low as 5 microM and it is dose-dependent with a 9.6 microM ED50. CisDDP also boosts the inhibition of the polarization caused by 10 microM tetrodotoxin (TTX) and 10 microM doxorubicin (DOXO). The replacement of Na+ by choline and the inactivation of Ca2+ by EGTA, in the incubation medium, reduces the inhibiting effect of cisDDP on the KCl-induced depolarization. These results suggest that cisDDP induced alterations could be due to the interference of cisDDP with the activity of the ionic channels pertaining to Na+ and Ca2+. This interference is stronger for Na+ channels.

The effect of age and sex on the expression of prolactin binding activity in the chicken bursa of Fabricius.

The binding of 125I-labeled prolactin (PRL) to membranes from the bursa of Fabricius of male and female chicks of different ages (15-30-45 and 60 days) was studied. In male chicks the binding was very low in 15 day-old animals and slightly increased in more aged animals. In female chicks the binding was more evident in young animals and decreased in 60 day-old animals. The binding showed a hormonal specificity and Scatchard analysis of the binding revealed the presence of binding sites with low capacity and high affinity. The presence of PRL receptors in the bursa of the chick, a structure that confers immunological competence to birds, gives further support to the involvement of the hormone in the immune processes.

Regional distribution and species variation of prolactin binding sites in the brain.

The binding of 125I-labeled ovine prolactin (125I-oPRL) to membranes from different brain regions of pigeon, rabbit, rat, pig, calf, horse, and ewe was studied. The hypothalamus from rabbit, pig, horse, and pigeon showed a low but specific binding for 125I-oPRL clearly different from the other brain regions examined (cortex and cerebellum), whereas in the brain from rat, calf, and ewe the binding was very small and quite uniform in the various regions. Also the membranes from choroid plexus of rabbit, pig, calf, and horse showed an evident specific binding for prolactin. The binding of 125I-oPRL to hypothalamus and choroid plexus membranes from rabbit and horse was inhibited in a dose-dependent manner by unlabeled oPRL and hGH but not by many other polypeptide hormones. Scatchard analysis of the binding revealed the presence of binding sites with low capacity and high affinity for ovine ligand.

[Neuropsychopharmacological effects of TCDD]. / Effetti neuropsicofarmacologici della TCDD.

It has been found that TCDD (2,3,7,8-tetrachlorodibenzo-p-dioxin), in rats, endoperitoneally or orally administered at dose of 1-10 mcg/kg, provokes irritability, aggressivity and restlessness (increase of spontaneous crossings in the shuttle box). The TCDD does not modify the conditioned avoidance (C.A.) or the conflictual situation. In "vitro" the TCDD stimulates directly the striatal and hypothalamic adenylate cyclase of rat. The TCDD increases the stimulation produced by dopamine on striatal adenylate cyclase. Haloperidol (dopamine antagonist) inhibits the stimulation produced by TCDD. TCDD does not significantly modify the stimulation by hystamine on hypothalamic adenylate cyclase. Cimetidine (H2) antagonist) causes a remarkable increase of the TCDD stimulating effect.

Effects of bromocriptine on adenylate cyclase and phosphodiesterase activities of rat striatum.

The activity of 2-bromo-alpha-ergokryptine (bromocriptine) (5 mg kg-1, i.p.) on adenylate cyclase and on phosphodiesterase (PDE-PDE II) of rat striatum, has been examined both in vitro and in vivo. In vitro and in vivo bromocriptine stimulated adenylate cyclase activity, but reduced the stimulating effect of dopamine on adenylate cyclase activity. Bromocriptine showed a dose-dependent biphasic action on phosphodiesterases in vitro while in vivo it stimulated them. The results obtained proved bromocriptine to have an agonist-antagonist action at striatal dopamine receptor level, with a relevant effect on the cAMP system.