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PubMed1999

Differences in the attitudes of couples whose children were conceived through artificial insemination by donor in 1980 and in 1996.

OBJECTIVE: To compare the attitudes of couples whose children were conceived through artificial insemination by donor (AID) in 1980 and in 1996. DESIGN: Replication study. SETTING: Infertility clinic of the Utrecht university hospital. PATIENT(S): Couples who conceived a child through AID in 1980 (n = 134) or in 1996 (n = 110). INTERVENTION(S): Anonymous questionnaires. MAIN OUTCOME MEASURE(S): Answers to questionnaires. RESULT(S): Couples who conceive a child through AID still strongly prefer (84%) absolute anonymity of the donor. In both 1980 and 1996, most couples (approximately 80%) decided not to inform their child about the nature of his or her conception. In 1996, couples who considered informing their child hesitated significantly less and showed significantly more openness toward others. In addition, more couples wanted unidentifiable data about the donor and considered it more important to use the same donor for a subsequent child. CONCLUSION(S): Between 1980 and 1996, the number of couples who conceived a child through AID and adhered to absolute anonymity of the donor and secrecy toward the child remained the same, whereas their openness toward others and desire for unidentifiable data about the donor increased.

Attitude↗

PubMed2002

DNA-support coupling for transcription factor purification. Comparison of aldehyde, cyanogen bromide and N-hydroxysuccinimide chemistries.

Purification of transcription factor IIIA on internal control region DNA coupled to aldehyde-silica is described and compared with purification on cyanogen bromide-activated Sepharose and Bio-Rad Affi-Gel-10. The Affi-Gel support results in mixed-mode chromatography; both ion-exchange and affinity modes contribute. Coupling DNA to aldehyde-silica is advantageous in that it has no ion-exchange properties and performs as well as DNA coupled to CNBr-activated Sepharose. Purification of lac repressor on aldehyde-silica, and CAAT enhancer binding protein on Affi-Gel also shows the advantages of a neutral support and the disadvantages of mixed-mode chromatography for transcription factor purification. Aldehyde-silica couples to alkylamines and to the amines of adenine, guanine, and cytosine nucleoside bases. Reaction occurs with either single- or double-stranded DNA, although it is less efficient with the latter. Overall, the results demonstrate that predominantly neutral coupling chemistries, such as aldehyde or CNBr-mediated coupling, have distinct advantages for transcription factor purification. Since the CNBr chemistry has not yet been applied to silica supports, aldehyde-silica coupling is currently the most attractive method for DNA affinity HPLC.

Aldehydes↗

PubMed2006

Intrauterine insemination with controlled ovarian hyperstimulation versus expectant management for couples with unexplained subfertility and an intermediate prognosis: a randomised clinical trial.

BACKGROUND: Intrauterine insemination with controlled ovarian hyperstimulation is commonly used as first-line treatment for couples with unexplained subfertility. Since such treatment increases the risk of multiple pregnancy, a couple's chances of achieving an ongoing pregnancy without it should be considered to identify those most likely to benefit from treatment. We aimed to assess the incremental effectiveness of intrauterine insemination with controlled ovarian hyperstimulation compared with expectant management in couples with unexplained subfertility and an intermediate prognosis of a spontaneous ongoing pregnancy. METHODS: 253 couples with unexplained subfertility and a 30-40% probability of a spontaneous ongoing pregnancy within 12 months were randomly assigned either intrauterine insemination with controlled ovarian hyperstimulation for 6 months or expectant management for 6 months. The primary endpoint of this hospital-based study was ongoing pregnancy within 6 months. Analysis was by intention to treat. This trial is registered with the Dutch Trial Register and as an International Standard Randomised Clinical Trial, number ISRCTN72675518. FINDINGS: Of the 253 couples enrolled, 127 were assigned intrauterine insemination with controlled ovarian hyperstimulation and 126 expectant management. In the intervention group, 42 (33%) women conceived and 29 (23%) pregnancies were ongoing. In the expectant management group, 40 (32%) women conceived and 34 (27%) pregnancies were ongoing (relative risk 0.85, 95% CI 0.63-1.1). There was one twin pregnancy in each study group, and one woman in the intervention group conceived triplets. INTERPRETATION: A large beneficial effect of intrauterine insemination with controlled ovarian hyperstimulation in couples with unexplained subfertility and an intermediate prognosis can be excluded. Expectant management for 6 months is therefore justified in these couples.

Adult↗

PubMed1979

HLA-A,B compatibility in parents of offspring with neural-tube defects or couples experiencing involuntary fetal wastage.

To test the contribution of a putative human analogue of the murine T locus to neural-tube defects (N.T.D.) and involuntary fetal wastage, HLA-A, B compatibility between husband and wife was studied in a group of 77 couples with known obstetric histories. The frequency of sharing of HLA-A,B antigens was significantly higher in 13 couples with recurrent fetal loss at one gestational age and in 11 couples whose offspring had had a lethal N.T.D. than in 17 couples with three or more normal pregnancies. The extent of HLA compatibility--that is, the number of antigens shared by husbands and wives--was significantly higher in 16 couples with one spontaneous abortion, 23 couples with recurrent spontaneous abortions, and 21 couples with N.T.D. offspring than in controls. These data are consistent with a contribution of a locus in or near the HLA complex to N.T.D. and involuntary fetal wastage.

Abortion, Spontaneous↗

PubMed1999

Platelet alpha2A-adrenoceptor function in major depression: Gi coupling, effects of imipramine and relationship to treatment outcome.

Studies suggest alpha2A-adrenoceptors (alpha(2A)AR) dysregulation in major depressive disorder (MDD). Platelet alpha(2A)ARs exist in high- and low-conformational states that are regulated by Gi protein. Although alpha(2A)AR coupling to Gi protein plays an important role in signal transduction and is modulated by antidepressants, it has not been previously investigated. Alpha2AR density in the high- and low-conformational states, agonist affinity and coupling efficiency were investigated in 27 healthy control subjects, 23 drug-free MDD patients and 16 patients after imipramine treatment using [3H]yohimbine saturation and norepinephrine displacement of [3H]yohimbine binding experiments. Coupling measures were derived from NE-displacement experiments. Patients had significantly higher alpha(2A)AR density, particularly in the high-conformational state, than control subjects. Coupling indices were normal in patients. High pre-treatment agonist affinity to the receptor in the high-conformational state and normal coupling predicted positive treatment outcome. Decreased coupling to Gi predicted a negative treatment outcome. Imipramine induced uncoupling (-11%) and redistribution of receptor density in treatment responders only, but had no effect on alpha(2A)AR coupling or density in treatment non-responders. Increased alpha(2A)AR density may represent a trait marker in MDD. The results provide indirect evidence for abnormal protein kinase A (PKA) and protein kinase C (PKC) in MDD which may be pursued in future investigations.

Adrenergic Uptake Inhibitors↗

PubMed2003

Gap junctional coupling in the olfactory organ of zebrafish embryos.

Intercellular communication through gap junctions is vital for many developmental processes, including cell division and synaptogenesis. This study is the first demonstration that olfactory organ cells are functionally coupled by gap junctions. Cell coupling was examined during development in the olfactory organ using gap junction permeable dyes in live zebrafish embryos. At 1 day post-fertilization (dpf), cells of the olfactory organ were not coupled by gap junctions. At 2 and 3 dpf, olfactory organ cells passed dye from one cell to another, indicating functional coupling via gap junctions. Coupled cell cohorts included combinations of all three olfactory cell types: basal cells, support cells, and olfactory receptor cells. As the olfactory organ matured, the number of cells per coupled cell cohort increased. Gap junctional coupling corresponded with maturation of the olfactory organ and indicates that functional gap junctions may be involved in proper development of the olfactory organ.

Animals↗

PubMed1999

Lumbar coupling during lateral translations of the thoracic cage relative to a fixed pelvis.

OBJECTIVE: To determine lumbar coupling during lateral postural translations (lumbosacral list) of the thoracic cage relative to a fixed pelvis. DESIGN: Digitized measurements from anteroposterior lumbar radiographs of 17 volunteers were obtained in neutral, maximal left lateral translation and maximal right lateral translation posture of the thoracic cage compared to a fixed pelvis. Subjects were constrained with two sets of clamps at the lateral borders of the pelvis and lower ribs. BACKGROUND: Data. Clinically, lumbosacral list is a common posture. Range of motion and spinal coupling results have not been reported for the lumbosacral list movement. METHODS: Four vertebral body corners, mid narrow-waisted body margins, superior and inferior pedicle margins, and spinous-lamina junction of T12-L5 were digitized on 51 anterior-posterior lumbar radiographs. Using the orthogonal axes of positive x-direction to the left, vertical as positive y, and anterior as positive z, digitized points were used to measure projected segmental z-axis rotation, y-axis rotation, and segmental lateral translations of each vertebra. RESULTS: Using the displacement of T12, subjects could translate 35-70 mm left or right along the x-axis with an average of 53.2 mm to the left and 52.1 mm to the right. Using superior endplates to superior sacral base, lateral flexion was largest at L1 and decreased from L1 to L5, but the segmental rotation angles for lateral flexion were largest at L2-L3 (3.9 degrees ), L3-L4 (6.2 degrees ) and L4-L5 (5.7 degrees ) and were in the same direction as the main motion translation. The relative z-axis rotation of T12 was opposite to the direction of L1-L5. The coupled y-axis rotations were less than 1 degrees and coupled segmental lateral translations were averaging less than 1 mm. CONCLUSIONS: Thoracic cage x-axis translations compared to a fixed pelvis are significant, between 35 and 70 mm. The z-axis lumbar coupled rotation was largest at L2-L3, L3-L4 and L4-L5 and to the same side of the main motion translation in L1-L5, but opposite the main motion direction for T12. All other movements were small, averaging less than 1 degrees or 1 mm. RELEVANCE: The clinically common posture of lateral translation of the thoracic cage (lumbosacral list) is often associated with disc herniation. Yet normal lumbar coupling patterns and total range of motion of this movement have not been established in the literature. Normal values for lumbar segmental coupling on anterior-posterior lumbo-pelvic radiographs during trunk list might be important for an analysis of segmental instability since segmental translations were determined to be 1 mm or less.

Adult↗

PubMed2001

Redox environment of the cell as viewed through the redox state of the glutathione disulfide/glutathione couple.

Redox state is a term used widely in the research field of free radicals and oxidative stress. Unfortunately, it is used as a general term referring to relative changes that are not well defined or quantitated. In this review we provide a definition for the redox environment of biological fluids, cell organelles, cells, or tissue. We illustrate how the reduction potential of various redox couples can be estimated with the Nernst equation and show how pH and the concentrations of the species comprising different redox couples influence the reduction potential. We discuss how the redox state of the glutathione disulfide-glutathione couple (GSSG/2GSH) can serve as an important indicator of redox environment. There are many redox couples in a cell that work together to maintain the redox environment; the GSSG/2GSH couple is the most abundant redox couple in a cell. Changes of the half-cell reduction potential (E(hc)) of the GSSG/2GSH couple appear to correlate with the biological status of the cell: proliferation E(hc) approximately -240 mV; differentiation E(hc) approximately -200 mV; or apoptosis E(hc) approximately -170 mV. These estimates can be used to more fully understand the redox biochemistry that results from oxidative stress. These are the first steps toward a new quantitative biology, which hopefully will provide a rationale and understanding of the cellular mechanisms associated with cell growth and development, signaling, and reductive or oxidative stress.

Cell Cycle↗

PubMed1999

Adrenergic receptor function in panic disorder. I. Platelet alpha 2 receptors: Gi protein coupling, effects of imipramine, and relationship to treatment outcome.

Various studies suggest alpha 2-adrenergic receptor (alpha 2AR) dysregulation in panic disorder (PD). Platelet alpha 2-AR exist in high- and low-conformational states as a function of their coupling to Gi protein. alpha 2AR coupling is important in signal transduction and is modulated by antidepressants. alpha 2AR density in the high- and low-conformational states, agonist affinity, and coupling efficiency were investigated in 21 healthy controls, 21 drug-free PD patients, and eight imipramine-treated patients using norepinephrine displacement of 3H-yohimbine binding. Percentage of receptors in the high-conformational state (%RH) and the ratio of the agonist dissociation constant to the receptor in the low-/high-conformational state (KL/KH), calculated from displacement experiments, were used as coupling indices. Patients had high alpha 2AR density in both conformational states. %RH and KL/KH ratio were significantly different, particularly in patients with Hamilton scale for depression (HAMD) scores > or = 15. Imipramine treatment (29 weeks) had no effect on alpha 2AR density or coupling, despite improvement in anxiety ratings. High pretreatment alpha 2AR density and coupling predicted low severity of anxiety after treatment. Increased alpha 2AR density and abnormal coupling may represent an adaptive mechanism or trait marker in PD.

Adult↗

PubMed2002

[What kind of support do couples expect when undergoing IVF treatment? Study and perspectives].

OBJECTIVES: To assess the management of the supportive aspects of treatment for couples having attempted an in vitro fertilization treatment. MATERIAL AND METHODS: Three groups of couples were contacted by questionnaire (successful treatment, unsuccessful treatment treatment, outcome still unknown). RESULTS: 48% considered it necessary to offer psychological support after the diagnosis. 80% considered it difficult to have a thorough representation of the physical aspects of an In Vitro Fertilization treatment but mostly they were surprised by their lack of an accurate emotional representation. All couples expected an availability and receptiveness from the infertility team but the unsuccessful treatment group was less satisfied and felt significantly (P < 0.001) less well supported. The most difficult moments mentioned were the numerous moments of waiting and the announcement of the final result. Emotional support was regularly provided by the nurses but 20% wanted psychological counselling. Two thirds of all couples considered that a psychological follow-up should be proposed to couples for whom the treatment remain unsuccessful. CONCLUSIONS: Results show the need for better emotional preparation of couples. As for the emotional support during treatment, the need for psychological counselling appears after the diagnosis of infertility as well as a constant demand of availability and empathy on behalf of the team. Post-treatment counselling may be particularly important also. Failure as well as lack of support at that time seemed to colour the way couples regard the whole support provided during treatments.

Adaptation, Psychological↗

PubMed2002

[Which psychological support for couples seeking medical assistance for procreation?].

OBJECTIVES: The objective of our qualitative study was to define modalities of psychological support to be offered to couples seeking medically assisted procreation. MATERIAL AND METHODS: Forty couples participated in a semi-structured videotaped interview, which touched on themes such as personal and family histories, the couple's relationship, etc. We focused on the "narrative mobility", that is the way in which the couples transmit their personal and family history during the interview and the interviewer's impression that he may or may not share this with the couples. RESULTS: Observed differences in narrative mobility led us to distinguish three groups of couples and to propose various types of psychological support. DISCUSSION AND CONCLUSION: This exploratory study, with its interest for the narrative mobility, concerns the couples' capacity to stand back from their own story as responsible interlocutors. We made the hypothesis that this capacity is linked to their capacity to handle their emotional stress, to act as partners to the medical team and to prepare themselves for their future parenthood.

Emotions↗

PubMed2000

NMR studies on derivatives of heteroaromatic compounds: exceptionally small carbon-carbon couplings, 1J(CC), in 2-lithiothiophene, 2-lithio-N-methylpyrrole and 2-lithiofuran.

Spin-spin carbon-carbon coupling constants across one bond and carbon proton coupling constants across one, two and three bonds have been measured for a large series of derivatives of five-membered heterocyclic compounds. This included 2-methyl and 2-lithio derivatives of furan, N-methyl pyrrole and thiophene and a series of 2-R-substituted thiophenes where R = O-t-Bu, Cl, Br, I, Si(CH3)3, MgBr and MgTh. For the long-range C-H couplings their signs have been determined in several compounds by the use of modern 2D NMR techniques, and in all the cases they have been found to be positive. A good linear dependence upon electronegativity of the substituent has been observed for 1J(CC), 2J(C2H3), and 3J(C2H4). Very small 1J(CC) couplings of ca. 30 Hz only have been found in all three lithio compounds; they belong to the smallest couplings of this type reported up to now. They are accompanied by very large and positive two-bond couplings, 2J(C2H3) of ca. +20 Hz, which in turn are the largest couplings of this type reported so far. In both cases the changes observed are interpreted in terms of the changes in the Fermi contact contribution.

Furans↗

PubMed1999

Catharanthine oxidation in flavin mononucleotide-mediated catharanthine-vindoline coupling reaction for synthesis of dimeric indole alkaloids under near-ultraviolet light.

A reaction model for the flavin mononucleotide-mediated coupling of catharanthine (C) and vindoline (V) under near-ultraviolet light was established based on the results of experiments on the effects of various physical and chemical factors on the disappearance of C and V, and the synthesis of the product, a dihydropyridinium intermediate (IM). The following events were deduced to occur. (i) C is oxidized in the presence of FMN and oxygen under near-ultraviolet light (C(OX1)). (ii) C(OX1) then couples with V to form IM. Degradation of C occurs simultaneously with its specific oxidation, as a result of which a part of the C is converted into the product (C*) which is incapable of coupling with V. When a reaction in which C(OX1) is further oxidized to another form (C(OX2)) is added and the counterpart for the coupling with V is changed to C(OX2) from C(OX1), the reaction model more appropriately describes the exponential increase in the product, IM, that occurs in the early stage of the coupling reaction. (iii) The degradation rate of IM is much greater after C has been consumed than before its disappearance. Using this reaction model, the coupling reactions under basal and optimized conditions were simulated and the results showed a good fit with the experimental values under both conditions. The kinetic study suggests that manganese ion (Mn2+) stimulates the binding of C(OX2) with V in addition to suppressing the degradation of C, resulting in an increased yield of IM. Mn2+ thus appears to be an important factor in the coupling reaction, in which it plays two different roles.

Journal Article↗

PubMedDate not supplied

Light-induced modulation of coupling between AII amacrine cells in the rabbit retina.

The rod-driven, AII amacrine cells in the mammalian retina maintain homologous gap junctions with one another as well as heterologous gap junctions with on-cone bipolar cells. We used background illumination to study whether changes in the adaptational state of the retina affected the permeabilities of these two sets of gap junctions. To access changes in permeability, we injected single AII amacrine cells with the biotinylated tracer, Neurobiotin, and measured the extent of tracer coupling to neighboring AII cells and neighboring cone bipolar cells. We also measured the center-receptive field size of AII cells to assess concomitant changes in electrical coupling. Our results indicate that in well dark-adapted retinas, AII cells form relatively small networks averaging 20 amacrine cells and covering about 75 microns. The size of these networks matched closely to the size of AII cell on-center receptive fields. However, over most of their operating range, AII cells formed dramatically larger networks, averaging 326 amacrine cells, which corresponded to an increased receptive-field size. As the retina was light adapted beyond the operating range of the AII cells, they uncoupled to form networks comparable in size to those seem in well dark-adapted retinas. Our results, then, indicate that the adaptational state of the retina has a profound effect on the extent of electrical coupling between AII amacrine cells. Although we observed light-induced changes in the number of tracer-coupled cone bipolar cells, these appeared to be an epiphenomenon of changes in homologous coupling between AII amacrine cells. Therefore, in contrast to the robust changes in AII-AII coupling produced by background illumination, our data provided no evidence of a light-induced modulation of coupling between AII cells and on-cone bipolar cells.

Adaptation, Physiological↗

PubMedDate not supplied

Photoreceptor coupling in turtle retina.

Photoreceptors in the isolated turtle retina of two species of turtle, Chelydra serpentina and Pseudemus scripta elegans, were penetrated with double-barrel electrodes. Physiological responses were recorded through one barrel and Neurobiotin tracer was injected from the other. Intracellular injection of Neurobiotin revealed patterns of tracer-coupled photoreceptors. Both the patterns of tracer coupling and the electrophysiology suggest a high degree of specificity of connections. Rods seem to be coupled only to rods and green and red cones seem to be coupled to cones of the same spectral type. Receptive-field profiles, measured with a thin, sharply focused slit of light, often had well-defined peaks and troughs in sensitivity. We have taken advantage of this observation and used the position of a peak in sensitivity to locate the position on the retina of a coupled cell. In one rod, it was possible to correlate physiological and morphological data and to show that the peaks in the physiological receptive field occurred at positions on the retina where there were dye-coupled cells. This provides direct evidence that gap junctions produce the physiological coupling between rods.

Animals↗

PubMed1992

Hydrogen bonding to the bound dioxygen in oxy cobaltous myoglobin reduces the superhyperfine coupling to the proximal histidine.

Electron spin echo envelope modulation (ESEEM) spectroscopy was used to study the electron-nuclear coupling in two oxygenated cobalt-substituted hemoproteins, myoglobin (oxyCoMb) and a monomeric hemoglobin from Glycera dibranchiata (oxyCoHbgly). The modulation frequency components in ESEEM spectra of both proteins arose from the coupling to the N epsilon of the proximal histidyl imidazole. The hyperfine and quadrupole coupling parameters for these two nitrogens, calculated by computer spectral simulation, are Aiso = 2.46 MHz, e2qQ = 2.15 MHz, and eta = 0.4 for oxyCoMb and Aiso = 3.70 MHz, e2qQ = 2.70 MHz, and eta = 0.5 for oxyCoHbgly. A hyperfine coupling of 0.6 MHz, found for oxyCoMb in D2O but not for oxyCoHbgly in D2O, was assigned to the coupling to a deuteron that is hydrogen-bonded to the O2 ligand in oxyCoMb. This hydrogen bonding is believed to be responsible for the reduction in hyperfine and nuclear quadrupole coupling to the proximal histidyl imidazole N epsilon in oxyCoMb. A molecular orbital model for O2 adducts of cobaltous compounds [Tovrog et al. (1976) J. Am. Chem. Soc. 98, 5144] was used to understand the hydrogen bond-induced reduction in 14N superhyperfine coupling in oxyCoMb.

Animals↗

PubMed1985

Vicinal coupling constants and protein dynamics.

The effects of motional averaging on the analysis of vicinal spin-spin coupling constants derived from proton NMR studies of proteins have been examined. Trajectories obtained from molecular dynamics simulations of bovine pancreatic trypsin inhibitor and of hen egg white lysozyme were used in conjunction with an expression for the dependence of the coupling constant on the intervening dihedral angle to calculate the time-dependent behavior of the coupling constants. Despite large fluctuations, the time-average values of the coupling constants are not far from those computed for the average structure in the cases where fluctuations occur about a single potential well. The calculated differences show a high correlation with the variation in the magnitude of the fluctuations of individual dihedral angles. For the cases where fluctuations involve multiple sites, large differences are found between the time-average values and the average structure values for the coupling constants. Comparison of the simulation results with the experimental trends suggests that side chains with more than one position are more common in proteins than is inferred from X-ray results. It is concluded that for the main chain, motional effects do not introduce significant errors where vicinal coupling constants are used in structure determinations; however, for side chains, the motional average can alter deductions about the structure. Accurately measured coupling constants are shown to provide information concerning the magnitude of dihedral angle fluctuations.

Amino Acids↗

PubMed1990

Direct and indirect pathways of functional coupling in human hemoglobin are revealed by quantitative low-temperature isoelectric focusing of mutant hybrids.

Functional energetic coupling within human hemoglobin has been explored by using quantitative analysis of asymmetric mutant hybrid equilibria. Previous work showed that the free energy of cooperativity is largely attributable to alterations in free energy that accompany changing interactions at the interface between alpha 1 beta 1 and alpha 2 beta 2 dimers [Pettigrew et al. (1982) Proc. Natl. Acad. Sci. U.S.A. 79, 1849]. However, the issue of how cooperativity-linked sites in the molecule are energetically coupled in manifesting cooperative ligation is still not well delineated. In this paper we address the questions of what types of functional coupling pathways are operational in hemoglobin, what some of their characteristics are, and how they are related to one another. By constructing asymmetric mutant hybrid hemoglobins, we can assay how two structurally identical, symmetrically equivalent sites are energetically coupled in manifesting subunit assembly and/or cooperative ligation. Asymmetric hybrid hemoglobins, i.e., those containing a single modified site, cannot be isolated and must be studied in equilibrium with their symmetric parent molecules. In order to study these asymmetric hybrid equilibria, we have developed new theory and quantitation techniques to augment the low-temperature quenching and isoelectric focusing procedures of Perrella et al. [(1978) Anal. Biochem. 88, 212]. Studies of these mutant hybrid hemoglobins have provided evidence for three distinct types of energetic coupling within the hemoglobin tetramer. All alpha 1 beta 2 interface sites examined are involved in cooperativity-linked indirect coupling. Within the context of this indirect "pathway" there exist two different types of direct long-range coupling. One of these classes of direct long-range pathways is linked to cooperative ligand binding while the other class is not.

Cold Temperature↗