Effect of leptin on the regulation of placental hormone secretion in cultured human placental cells.

Placenta is an important source of leptin during pregnancy that contributes to the high plasma leptin levels in pregnant women. Leptin and its functional receptors are synthesized in trophoblast cells that, in turn, secrete gestational hormones supporting a paracrine or autocrine role for leptin in the endocrine activity of the placenta. In the present study we examined the effect of leptin on in vitro release of gestational hormones (human chorionic gonadotropin (hCG), human placental lactogen (hPL), progesterone, estrogens and testosterone) by human term placental cells in culture. Placentas at term were obtained immediately after delivery from mothers with uncomplicated pregnancies. Progesterone, hCG, hPL, estradiol, estrone, estriol and testosterone levels were measured by different assays in culture media of cells maintained in monolayer culture after incubation for 12, 24, 48 or 72 h with leptin or placebo. Incubation with leptin did not modify hCG, hPL, progesterone, estriol and estrone secretion for any of the doses and times assayed. However, leptin led to a dose-dependent decrease in estradiol release. This effect was observed when treatment with recombinant human leptin spanned from 12 to 72 h. At this time an increase in testosterone levels was observed in leptin-treated cells versus placebo. These results indicate that leptin can be considered a gestational hormone implied in the endocrine function of the placenta, with an important role in control of the production of steroid reproductive hormones in placental cells in vitro.     

Knee-ankle-foot orthosis in children with duchenne muscular dystrophy: user views and adjustment.

BACKGROUND: The use of knee ankle foot orthoses (KAFOs) to prolong independent mobility is a widely used rehabilitation strategy for children with Duchenne muscular dystrophy (DMD). AIMS: To explore views and adjustment of families with a child with Duchenne muscular dystrophy to the use of KAFOs. METHODS: interviews with families of children aged 8-18 years with DMD; questionnaires on psychiatric adjustment (SDQ for children; GHQ for parents). RESULTS: In total, 17 parents and 9 children took part. Families experienced the introduction of KAFOs as a signal for illness deterioration and a re-awakening of the feelings experienced at diagnosis. Nevertheless, the majority expressed a positive attitude and over two-thirds satisfaction with KAFOs use. High psychiatric risk was found in 2/17 children (12%; expected 10%) and 7/17 main carers (41%; expected 20-30%). CONCLUSION: Most families were satisfied with KAFOs use, and its implementation was well tolerated especially by the children. However, mental distress was high in main carers who emphasized the importance of full preparation and support in this rehabilitation technique.     

Hydrophobicity of β-adrenoceptor blocking agents: Study of correlations between retention in reversed-phase HPLC systems and octanol-water partition constants

The capacity factors (k′) of seven β-adrenoceptor blocking agents in six different reversed-phase HPLC systems have been determined. Octanol-aqueous buffer (pH 7.4) partition constants (P) for these blocking agents were also obtained. By using target factor analysis (TFA), good empirical correlations between the log k′ and log P were derived. The resulting hydrophobicity order agrees well with the metabolic elimination pathways of these drugs.     

Elimination and minimization of the spherical aberration of intraocular lenses in high myopia

By applying Seidel aberration theory we have studied the spherical aberration of intraocular lenses in place ( S _IL), and the total spherical aberration of pseudophakic eyes ( S _IT). The optimum lens shapes for zero S _IL and S _IT or for minimum S _IL and S _IT of 12 schematic, highly myopic eyes were investigated. When the power required for emmetropization is positive, the total Seidel spherical aberration of the whole eye cannot be zero but can only be minimized. If the power of the intraocular lens is negative, the total Seidel spherical aberration of the whole eye can be made zero, and one of the optimum lens shapes would be meniscus with the convex surface towards the retina. In addition to improving the quality of the image, the lens has advantages from the physiological point of view, since it helps to maintain the structure of the eye.     

Partial-solubility Parameters of Naproxen and Sodium Diclofenac

The expanded Hansen method was tested for determination of the solubility parameters of two non-steroidal anti-inflammatory drugs, naproxen and sodium diclofenac. This work describes for the first time the application of the method to the sodium salt of a drug. The original dependent variable of the expanded Hansen method, involving the activity coefficient of the drug, was compared with the direct use of the logarithm of the mole fraction solubility lnX₂ in the solubility models. The solubility of both drugs was measured in pure solvents of several chemical classes and the activity coefficient was obtained from the molar heat and the temperature of fusion. Differential scanning calorimetry was performed on the original powder and on the solid phase after equilibration with the pure solvents, enabling detection of possible changes of the thermal properties of the solid phase that might change the value of the activity coefficient. The molar heat and temperature of fusion of sodium diclofenac could not be determined because this drug decomposed near the fusion temperature. The best results for both drugs were obtained with the dependent variable lnX₂ in association with the four-parameter model which includes the acidic and basic partial-solubility parameters δ_a and δ_b instead of the Hansen hydrogen bonding parameter δ_h. Because the dispersion parameter does not vary greatly from one drug to another, the variation of solubility among solvents is largely a result of the dipolar and hydrogen-bonding parameters, a fact that is being consistently found for other drugs of small molecular weight. These results support earlier findings with citric acid and paracetamol that the expanded Hansen approach is suitable for determining partial-solubility parameters. The modification introduced in the expanded Hansen method, i.e. the use of lnX₂ as the dependent variable, provides better results than the activity coefficient used in the original method. This is advantageous for drugs such as sodium diclofenac for which the ideal solubility cannot be estimated. This paper shows for the first time that the method is suitable for determination of the partial-solubility parameters of a sodium salt of a drug, sodium diclofenac.     

Morphology of temperate bacteriophage SfV and characterisation of the DNA packaging and capsid genes: the structural genes evolved from two different phage families

The entire genome of SfV, a temperate serotype-converting bacteriophage of Shigella flexneri, has recently been sequenced (Allison, G.E., Angeles, D., Tran-Dinh, N., Verma, N.K. 2002, J. Bacteriol. 184, 1974-1987). Based on the sequence analysis, we further characterised the SfV virion structure and morphogenesis. Electron microscopy indicated that SfV belongs to the Myoviridae morphology family. Analysis of the proteins encoded by orf1, orf2, and orf3 revealed that they were homologous to small and large terminase subunits, and portal proteins, respectively; the protein encoded by orf5 showed homology to capsid proteins. Western immunoblot of the phage with anti-SfV sera revealed two antigenic proteins, and the N-terminal amino acid sequence of the 32-kDa protein corresponded to amino acids 116 to 125 of the ORF5 protein, suggesting that the capsid may be processed. Functional analysis of orf4 showed that it encodes the phage capsid protease. The proteins encoded by orfs1, 2, 3, 4, and 5 are homologous to similar proteins in the Siphoviridae phage family of both gram-positive and gram-negative origin. The capsid and morphogenesis genes are upstream and adjacent to the genes encoding Myoviridae (Mu-like) tail proteins. The organisation of the structural genes of SfV is therefore unique as the head and tail genes originate from different morphology groups.     

CD4+ T cells determine the ability of spleen cells from F1 hybrid mice to induce neonatal tolerance to alloantigens and autoimmunity in parental mice

Spleen cells from F₁ hybrid mice injected into newborn parental mice induce a state of cytolytic unresponsiveness to the corresponding alloantigens. However, these mice develop a transient autoimmune syndrome characterized by the production of multiple autoantibodies and glomerulonephritis. Previous reports indicated that the depletion of F₁ donor T cells, shortly prior the injection into parental mice, does not interfere with any of these events. Here, we have explored whether the continuous absence of T cells in F₁ mice influences the ability of their spleen cells to induce neonatal tolerance to alloantigens and the associated autoimmune manifestations. Our results revealed that spleen cells from athymic (BALB/c × C57BL/6) F₁ hybrid (CB6F₁) nulnu mice or from euthymic CB6F₁ mice depleted from birth of CD4⁺ T cells, but not of CD8⁺ T cells, are unable to induce neonatal tolerance to alloantigens and autoimmune manifestations. By contrast, the partial reconstitution of T cells in CB6F¹ nulnu mice, after the neonatal graft of a syngeneic thymus, restored the capacity of spleen cells from these mice to induce tolerance and autoimmunity when injected into newborn BALB/c mice. These results demonstrate that the functional defect of spleen cells from athymic CB6F₁ nulnu mice to induce neonatal tolerance to alloantigens is directly related to the long-term absence of mature CD4⁺ T cells. Interestingly, a new increase in the titers of anti-DNA Ab was observed when spleen cells from athymic CB6F₁ nulnu mice were injected into adult BALB/c mice that had been tolerized at birth with normal CB6F₁ spleen cells. This finding indicates that B cells from CB6F₁ nulnu mice recover their capacity to interact with alloreactive Th2 cells when they are placed into mice having functional CD4⁺ T cells. These data indicate that the continuous absence of CD4⁺ T cells causes a reversible functional defect in F₁ spleen cells that determines their inability to induce neonatal tolerance and autoimmunity.     

Transmission of HIV-1 infection between trophoblast placental cells and T-cells take place via an LFA-1-mediated cell to cell contact

HIV-1 vertical transmission is thought to mainly take place by virus crossing the placental barrier. However, the mechanism by which HIV-1-infects placental cells remains to be elucidated. We have found that purified cytotrophoblasts as well as trophoblastic cell lines are susceptible to infection by different HIV-1 isolates as detected by DNA-PCR and release of infectious virus, although with very low efficiency. Purified trophoblast or trophoblastic cell lines express low levels of chemokine receptors CCR-5 and CXCR-4 but not CD4 on the cell surface. To test if those molecules were used as receptors for HIV-1 infection, placental cells were pretreated with antibodies to CD4, CC-chemokines, C-X-C chemokines. None of those treatments inhibited HIV-1 infection. In contrast, we have found that HIV-1 infection of placental cells was increased in cocultures of infected T-cell blasts and placental cells. More interestingly, antibodies to beta(2) integrins and to LFA-1 were able to significantly block infection of placental cells. Cell surface expression of ICAM-1, an adhesion molecule involved in attachment of leukocytes to placenta, was upregulated in HIV-1-infected placental cells. Placental cells were able to transfer HIV-1 infection to T-cell blasts. This transmission required cell to cell contact and was also inhibited by anti-LFA-1 antibodies. In summary our results suggest that placental trophoblast could be infected by HIV-1 by a mechanism involving T cell to placental contact. Moreover, placental infection enhanced ICAM-1 expression and leukocyte adherence, an event which was required to transfer HIV-1 infection to T cells. This provides an explanation of the virus passing through the placental barrier during in utero HIV-1 vertical transmission.