Strongly nonlinear dynamics of ferroelectric liquid crystals.

Molecular reorientation processes induced in thin ferroelectric liquid crystal systems by strong alternating external electric fields are studied both by solving numerically the equation of reorientation motion of molecules and by measuring the electro-optic response of thin samples. It is shown that the occurrence of a wide band in nonlinear response spectra above the Goldstone-mode frequency is a consequence of complex partially uncorrelated molecular reorientations enforced within smectic layers by sufficiently high fields of high enough frequencies. Such nonlinear reorientational motions of molecules are argued to have a character of weakly chaotic long-lasting transients, related to almost periodic modulations of the amplitude of rotational oscillations performed by molecules with the field frequency. These modulations have been numerically proved to proceed with lower frequencies than the field frequency and with space-dependent depths of temporal changes. The occurrence of the modulations has experimentally been confirmed by registering distinct contributions to electro-optic response spectra at frequencies less than the running frequency of the applied electric field.

Digit ratio (2D:4D) in women and men with lung cancer.

A prenatal sex steroid environment of high prenatal testosterone and low prenatal oestrogen inhibits lung development and may predispose individuals to be vulnerable to lung disease in later life. Therefore, the aim of this report was to investigate whether there is an association between right and left 2D:4D (biomarker of prenatal sex steroids exposure) and primary lung cancer in women and men. Also, we considered the relationship between right-left 2D:4D (Δ2D:4D, a negative correlate of high prenatal testosterone and low prenatal oestrogen) and the age of lung cancer diagnosis. The study included 109 patients (61 men) with lung cancer and 197 controls (78 men). In the study we found that: (i) women with lung cancer have lower 2D:4D compared to controls (the effect was independent of smoking), (ii) among women with cancer, age at diagnosis was positively related to 2D:4D, i.e. women with masculinized 2D:4D present earlier with the cancer than women with feminized 2D:4D, (iii) among men with lung cancer, those with the most aggressive form (small-cell lung cancer) had masculinized (low) Δ2D:4D compared to those with the less aggressive form (non-small cell lung cancer). The data suggests that masculinized right 2D:4D and Δ2D:4D are associated with a predisposition to lung cancer and/or the more aggressive forms of lung cancer.

Orientational order of difluorinated liquid crystals: a comparative 13C-NMR, Optical, and dielectric study in nematic and smectic B phases.

Structural and orientational order properties of 3Cy2CyBF2 and of 5CyCy2BF2 have been investigated by means of (13)C-NMR, optical, and dielectric spectroscopy methods. In the case of NMR, order parameters have been independently obtained from the analysis of either (13)C-(19)F dipolar couplings or (13)C chemical shift anisotropies, both measured from (13)C-{(1)H} NMR static spectra. The assignment of the (13)C resonances has been carried out thanks to the comparison with solution state spectra and DFT calculations, and the relevant geometrical parameters and (13)C chemical shift tensors needed to derive orientational order parameters have been calculated by DFT methods. In the analysis of (13)C-(19)F dipolar couplings, empirical corrections for vibrations and anisotropic scalar couplings have been included. Dielectric measurements have been performed over a broad frequency range for two orientations of the nematic director with respect to the measuring field. At low frequencies (static case) a positive dielectric anisotropy has been determined, which has enabled the calculation of the order parameters according to a well-tested procedure. At high frequencies the dielectric anisotropy changes its sign, a property which can be useful in designing a dual addressing display. The nematic order parameter determined from optical, dielectric, and NMR methods have been compared: their trends with temperature are very similar, apart from some slight shifts, and were analyzed by Haller and Chirtoc models. The differences among the results obtained by the four methods have been discussed in detail, also with reference to the assumptions and approximations used in each case, and to the results recently reported for similar fluorinated nematogens. The presence of a non-negligible order biaxiality has been related to the presence of a CH2CH2 bridging group, linking one cyclohexylic unit with either the other cyclohexyl or the phenyl ring.

A reappraisal of the role of insulin-like growth factor I in the regulation of human hematopoiesis.

IGF-I has been reported to increase hematopoietic progenitor cell cloning efficiency. To investigate this phenomenon, we studied the IGF-I responsiveness of human marrow cells expressing IGF-I receptor (IGF-IR), a direct strategy not used previously. IGF-IR+ and control CD34+ marrow cells were isolated using immunoaffinity methods. Then, the cells were cloned in methylcellulose containing variable amounts of serum- and lineage-appropriate growth factors supplemented with recombinant human IGF-I. In contrast to CD34+ cells, IGF-IR+ cells never gave rise to CFU-Blast, CFU-Mix, CFU-GM, BFU-E, or CFU-E. To substantiate the suggestion that CD34+ and IGF-IR+ cells were distinct populations, we used reverse transcription PCR to detect IGF-I, EpO, and KIT receptor mRNAs in these cells. The mRNA phenotype of CD34+ cells was EpO (+), KIT (+), and IGF-IR (-), while IGF-IR+ cells were IGF-IR (+), EpO (-), and KIT (-). These results suggested that IGF-IR is either not expressed or expressed at low levels on normal hematopoietic progenitor cells. Functional significance of the latter possibility was tested by exposing CD34+ cells to IGF-IR antisense oligodeoxynucleotides. Colony formation was unaffected by oligodeoxynucleotide disruption of IGF-IR, suggesting that, even if expressed at low level, the receptor's functional significance was doubtful. Nevertheless, when cultured in the presence of IGF-I, IGF-IR+ cells elaborated an activity with mild BFU-E stimulatory effects. Accordingly, if IGF-I plays a role in hematopoietic colony formation, it is probably and results from stimulation of IGF-IR-positive ancillary cells to secrete growth factors. Studies carried out with human leukemia cells yielded similar results.

Dielectric relaxation in chevron surface stabilized ferroelectric liquid crystals.

The dielectric response of surface stabilized ferroelectric liquid crystals with chevron layer structure is studied within low and intermediate frequency ranges, characteristic for collective molecular excitations. By analytically solving the dynamic equation for collective molecular fluctuations under a weak alternating electric field, it is demonstrated that chevron cells stabilized by both nonpolar and polar surface interactions undergo at medium frequencies two Debye relaxation processes, connected with two chevron slabs, on opposite sides of the interface plane. This result is confirmed, experimentally, making use of the electro-optic technique. Based on qualitative arguments supported by microscopic observations of zigzag defects at different frequencies and amplitudes of the external electric field, it is shown that, at low frequencies, the electro-optic response of chevron samples is determined by three kinds of motions of zigzag walls. The first two dynamic categories are related to collective relaxation processes at weak fields, within smectic A layers forming zigzag walls, and drift or creep motions of thick walls occurring at stronger field amplitudes. Dynamic processes of the third kind correspond to sliding of zigzag walls, which appear at yet stronger field amplitudes, but below the switching threshold.

Electric-field-induced weakly chaotic transients in ferroelectric liquid crystals.

Nonlinear dynamics induced in surface stabilized ferroelectric liquid crystals by strong alternating external electric fields is studied both theoretically and experimentally. As has already been shown, molecular reorientations induced by sufficiently strong fields of high-enough frequencies can reveal a long transient behavior that has a weakly chaotic character. The resulting complex dynamics of ferroelectric liquid crystals can be considered not only as a consequence of irregular motions of particular molecules but also as a repercussion of a surface-enforced partial decorrelation of nonlinear molecular motions within smectic layers. To achieve more insight into the nature of this phenomenon and to show that the underlying complex field-induced behavior of smectic liquid crystals is not exceptional, ranges of system parameters for which the chaotic behavior occurs are determined. It is proved that there exists a large enough set of initial phase trajectory points, for which weakly chaotic long-time transitory phenomena occur, and, thereby, it is demonstrated that such a chaotic behavior can be regarded as being typical for strongly field-driven thin liquid crystal systems. Additionally, the influence of low-amplitude random noise on the duration of the transient processes is numerically studied. The strongly nonlinear contribution to the electro-optic response, experimentally determined for liquid crystal samples at frequencies lower than the actual field frequency, is also analyzed for long-time signal sequences. Using a statistical approach to distinguish numerically response signals of samples from noise generated by measuring devices, it is shown that the distribution of sample signals distinctly differs from the device noise. This evidently corroborates the occurrence of the nonlinear low-frequency effect, found earlier for different surface stabilized liquid crystal samples.

Determination of piezoelectric and flexoelectric polarization in ferroelectric liquid crystals.

A method of determining the local polarization in chiral smectic liquid crystals is proposed. The method consists of simultaneous measurement of the electric permittivity and depth of electro-optic modulation in a helical liquid crystal using weak ac electric field. The spontaneous polarization of a single smectic layer determined in this way contains both the flexoelectric and piezoelectric component. On the other hand, the polarization measured using strong electric fields in a switching experiment contains the piezoelectric component only. The comparison of polarization obtained using strong and weak fields makes it possible to determine the value of flexoelectric polarization. This kind of measurement has been performed for two ferroelectric liquid crystals having quite small absolute values of the spontaneous polarization (few nC/cm2). It turned out that in both cases, the flexoelectric polarization is of the same order of magnitude as the piezoelectric one.

In vitro sensitivity of human hematopoietic progenitor cells to 4-hydroperoxycyclophosphamide.

Protracted engraftment and prolonged thrombocytopenia remain problems when marrow purged with 4-hydroperoxy-cyclophosphamide (4-HC) is employed for autotransplants. Toxic effects of 4-HC on early progenitor and stem cells might play an important causative role. Surprisingly, few investigations have examined the effects of 4-HC on progenitor cells other than colony-forming units-granulocyte/macrophage (CFU-GM) and burst-forming units-erythroid (BFU-E), and only one study could be found where 4-HC exposure was carried out on cells purified beyond the buffy coat stage. Since the cellular milieu, and in particular the red blood cell count, can ameliorate 4-HC toxicity, the suppressive effect of this agent on marrow stem cells might be underestimated. We therefore investigated the relative 4-HC sensitivity of different human bone marrow progenitor cells in vitro using partially purified adherent cell- and T lymphocyte-depleted bone marrow mononuclear cells (A-T-MNC). Cells were exposed to increasing doses (10 to 200 micrograms/mL) of 4-HC using a standard purging protocol established for bone marrow buffy coat cells. Effects on mixed (CFU-Mix), erythroid (CFU-E and BFU-E), granulocyte-macrophage (CFU-GM), and stromal cell (CFU-F) progenitors were determined. In addition, we examined the 4-HC sensitivity of megakaryocyte progenitors (CFU-Meg) since, to our knowledge, this has not been reported before. As expected, increasing doses of 4-HC led to progressive inhibition of hematopoietic colony formation. CFU-F, CFU-Mix, and CFU-Meg appeared most resistant to 4-HC exposure, while CFU-E, BFU-E, and CFU-GM appeared most sensitive. At doses over 100 micrograms/mL, the usual concentration recommended for purging of buffy coat cells, hematopoietic colony formation was completely inhibited. These data suggest that if more highly purified marrow cells are employed for purging, lower 4-HC doses may need to be used. They also suggest that the thrombocytopenia that frequently accompanies 4-HC purging is not likely due to loss of CFU-Meg.

Evidence for a functional kit receptor in melanoma, breast, and lung carcinoma cells.

We sought to determine the functional significance of the c-kit receptor (Kit) in melanoma, breast carcinoma, and non-small cell lung cancer (NSCLC). To explore these issues, we first screened cell lines of each type for c-kit mRNA expression using a reverse-transcription polymerase chain reaction. We found that WM-39 melanoma cells, HTB-22 breast carcinoma cells, and A549 NSCLC cells all expressed c-kit mRNA. Of interest, all of these cells expressed the c-kit ligand, Steel factor (SF). We then assessed the functional significance of c-kit and SF expression by disrupting the gene's expression with antisense (AS) oligodeoxynucleotides (ODN) targeted to c-kit mRNA codons 1-6 and SF mRNA codons 2-7, respectively. Nonhybridizing sequences [sense (5) and scrambled (SCR)] were also employed as controls. WM-39, HTB-22, and A549 cells were exposed to ODN (approximately 25 microM) for 5-7 days. Downregulation of c-kit and SF mRNA, and c-kit protein was demonstrated in cells treated with AS ODN. Effects on viable cell growth were demonstrated by the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) or 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4 -sulfophenyl)- 2H-tetrazolium (MTS) assay. In fact, c-kit antisense ODN inhibited the viable cell growth of A549 cells 66% and 79% compared to sense and untreated controls (P = .0003; P < .0001). Additionally, WM-39 cell growth was inhibited 48% and 21% (P < .0001, P < .03) and HTB-22 cell growth was inhibited 50% (P < .001) compared to sense and untreated controls. Viable cell growth was also significantly inhibited by SF AS ODN compared to S and SCR controls in all cell lines. These results demonstrate that WM-39, HTB-22, and A549 NSCLC cells all express the c-kit and SF protooncogenes and suggest that the encoded receptor and ligand are important for cell growth. By finding the presence, and functional importance, of both the receptor and ligand in these cells, this study suggests the existence of an autocrine loop growth mechanism worthy of further study.

Nonenzymatic antioxidant activity of human seminal plasma.

OBJECTIVE: To examine the nonenzymatic antioxidant properties of human seminal plasma. DESIGN: Determination of total (peroxyl) radical-trapping antioxidant parameter and malondialdehyde concentration in seminal plasma of 112 men attending IVF-ET or intracytoplasmic sperm injection (ICSI) programs. SETTING: University-based center for reproductive medicine. PATIENT(S): Normozoospermic men, ages 25 to 50 years, of fertility proved by a pregnancy resulting from IVF-ET, and men ages 25 to 50 years with negative IVF-ET or ICSI outcome, distinguished by their smoking status. INTERVENTION(S): Seminal plasma was obtained from ejaculates collected for IVF-ET or ICSI procedures. MAIN OUTCOME MEASURE(S): Total (peroxyl) radical-trapping antioxidant parameter and malondialdehyde concentrations. RESULT(S): No significant differences for total (peroxyl)-radical-trapping antioxidant parameter were observed between normozoospermic IVF-ET or asthenozoospermic ICSI patients; neither was a difference revealed for pregnancy-positive or -negative couples within those groups. Age, smoking status, or increased leukocyte count had no effect on total (peroxyl) radical-trapping antioxidant parameter or malondialdehyde concentrations in seminal plasma. CONCLUSION(S): Nonenzymatic antioxidant activity in seminal plasma does not reflect sperm fecundity ability.

Human Sertoli cells in vitro. Lactate, estradiol-17 beta and transferrin production.

Human Sertoli cell parameters, namely lactate, estradiol-17 beta, and transferrin production, were determined after a 24-hour incubation with either human follicle stimulating hormone (FSH) or dbcAMP in the presence or absence of testosterone plus a phosphodiesterase inhibitor (1-methyl-3-isobutylxanthine; MIX). Testicular tissues were obtained from 10 young patients (mean age, 29 years); using a 3-step enzymatic treatment, Sertoli cell enriched preparations (> 92%) were studied after 4 days as primary cultures. No significant changes in lactate, estradiol-17 beta, and transferrin outputs have been observed according to age in patients ranging in age from 16 years to 47 years. Sertoli cell production of the compounds is controlled by testosterone plus MIX; FSH (or dbcAMP) treatment only slightly improves their synthesis. It is suggested that human Sertoli cell function, as far as the parameters measured in this study are concerned, is likely regulated by cAMP-dependent and independent pathways.

Influence of different temperature of cryopreservation on the proliferative potential of human bone marrow progenitor cells. Transplantological implications.

The influence of two different temperatures of cryopreservation of human bone marrow on the proliferative potential of granulocyto-monocytic (GM-CFU), erythroid (BFU-E) and megakaryocytic (CFU-Meg) progenitors was investigated. For this purpose, the human bone marrow cells were cryopreserved in the standard freezing medium supplemented with 10% DMSO and stored at -80 degrees C in a freezer or at -196 degrees C in a liquid nitrogen tank. Subsequently, cells were thawed, plated and stimulated in vitro to grow myeloid colonies. Unexpectedly, bone marrow cells stored at -80 degrees C formed about 60%, and those stored at -196 degrees C formed barely 8% of CFU-GM and BFU-E colonies respectively, in comparison to control non-frozen cells. CFU-Meg progenitors appeared to be the most sensitive to cryopreservation among all clonogeneic cells tested. The number of CFU-Meg derived colonies decreased to 20% in marrow cryopreserved at -80 degrees C and to about 2% in cells stored in liquid nitrogen at -196 degrees C. These data demonstrate the advantages of bone marrow storage at -80 degrees C over freezing in liquid nitrogen at -196 degrees C. Moreover, the increased sensitivity of CFU-Meg to cryopreservation could explain, at least partially, the clinical phenomenon of protracted thrombocytopenia observed in patients transplanted with the cryopreserved bone marrow cells.

The influence of 4 degrees C storage on proliferative potential of human bone marrow CD34+ cells. Transplantological implications.

The possibility of storage of human bone marrow CD34+ cells at 4 degrees C was investigated for bone marrow transplantational purposes. The cells were placed in Iscove medium supplemented with 20% serum (15% bovine calf serum 5% human AB serum) for three weeks at 4 degrees C. During the storage time, clonogenecity of granulocyto-monocytic (CFU-GM) erythropoietic (BFU-E) and megakaryocytic (CFU-Meg) progenitors was investigated. It was found that it is possible to keep human CD34+ cells at 4 degrees C, at least for a few days before transplantation. At day four of the storage, the number of CFU-GM and BFU-E cells still exceeded 50% of the cells present at day 0. However, we have found that CFU-Meg in comparison to other progenitors are much more sensitive to metabolic storage stress. This enhanced sensitivity of megakaryocytic progenitors could explain, at least partially, the well known phenomenon of retardation of the thrombopoietic recovery in patients undergoing bone marrow transplantations.

Cytokine stimulation of CD34+ bone marrow cells prior to cryopreservation enhances their post-thawing proliferative potential.

Marrow aplasia remains a significant cause of morbidity and mortality in the peri-transplant period. Administration of recombinant human hematopoietic growth factors along with the marrow graft is a widely used strategy to ameliorate this problem. Though arguably effective, this approach is extremely expensive. To develop alternative strategies for stimulating marrow engraftment, we investigated the utility of stimulating CD34+ enriched bone marrow cells with cytokines prior to cryopreservation. We found that culturing these cells for 1 to 3 days in Iscove's medium supplemented with kit ligand (KL), interleukin-3 (IL-3), interleukin-1 beta (IL-1 beta) and 20% bovine calf serum before freezing doubled the proliferative capacity of both myeloid and erythroid progenitor cells after thawing. Confirmation of increased proliferative activity in vivo would suggest that this approach might significantly shorten the period of marrow aplasia post transplant at far less expensive means.

[Plasma fibrinolytic activity after gynecologic surgery]. / Aktywnosc fibrynologiczna osocza po operacjach ginekologicznych.

Fibrinolytic activity and fibrinolytic potential has been estimated in women submitted of gynecologic operations. Results was referred to age, extension of the operation and character of illness. Elevation of fibrinolytic activity immediately after operation and fibrinolytic potential five days later have been stated.

[Electroejaculation and lower motor neuron lesion: a report of cases]. / Elektroejakulacja a uszkodzenie dolnego motoneuronu. Opis przypadków.

Semen was obtained by transrectal electrostimulation from two spinal injured men who had not ejaculated since their injuries. Vibratory stimulation was unsuccessful. Side effect-pain, was reported in one of the patient. A silicone catheter was used to tamponade the bladder neck and antegrade ejaculations were collected with no incidences of urine contamination and no sperm were seen in post ejaculatory urine.

[The use of a vibrator for the stimulation of ejaculation in men with spinal cord injury]. / Zastosowanie wibratora celem wywolania ejakulacji u pacjentów z uszkodzeniem rdzenia kregowego.

Authors have presented results of vibratory stimulation in 20 anejaculatory spinal cord injury men. In 17 of 20 patients who had not ejaculated since their injuries, application of a vibrator to the penis caused ejaculation. Three of them had retrograde ejaculation. All patients with upper thoracic lesions received nifedipin. Side effects of vibratory stimulation were not reported. Semen can be used for assisted reproductive techniques.

[Electroejaculation--effectiveness in a patient after retroperitoneal lymph node dissection--case report]. / Elektroejakulacja--skutecznosc zabiegu u pacjenta po usunieciu pozaotrzewnowych wezlów chlonnych--opis przypadku.

Semen was obtained by transrectal electrostimulation from male patient after retroperitoneal lymph node dissection who had not ejaculated since time of operation. Vibratory stimulation was unsuccessful. electroejaculation was done under general anaesthesia. A silicone catheter was used to tamponade the bladder neck and antegrade ejaculations were collected. The semen underwent seminological assessment and then was diluted 1:1 in egg yolk substrate containing 15% glycerol, equilibrated, divided into straws and frozen in nitrogen. The straws were then placed for storage in liquid nitrogen until the insemination.

[Diagnostic laparoscopy in the gynecology clinic at the academy of medicine in Bialystok during the years 1989-91]. / Laparoskopia diagnostyczna w klinice ginekologii akademii medycznej w Bialymstoku w latach 1989-91.

The authors present the results of 1056 diagnostic laparoscopies carried out from 1989 to 1991 in the Clinic of Gynecology of Medical School in Bialystok. Sterility was the leading indication for diagnostic laparoscopies in 92.7% of patients. Suspicion of ectopic pregnancy was the reason of 44 laparoscopies. 46.5% of diagnosed infertile women had adhesions in pelvis post inflammation or surgery. 10.6% of them had massive pelvic adhesions and the tubes were damaged without any chance for surgical correction. The endometriosis was found in 15% of infertile women, and 17% of patients had no pelvic pathology.

[Enzymatic assisted hatching in the infertile couple after failed attempts of IVF ET]. / Enzymatyczne usuniecie oslonki przejrzystej blastocysty pronaza u pacjentek po kilkukrotnych niepowodzeniach w programie IVF ET.

The study was conducted on the patients who had attempted and failed previous IVF procedures. The aim of this study was to determinate effectiveness sequential culture of embryos to blastocyst and assisted hatching by zona pellucida digestation by pronase. In this group the pregnancy rate was 24.1% compared to control 17.8%. The implantation rate was higher in study group than control one. It suggests that the culture embryos to balstocyste stage and assisted hatching by digestation by pronase is safe and effective mode of treatment of infertile couple after failed attempts IVF ET.