Active oxygen forms in photoreaction between DNA and furanochromones khellin and visnagin

The two furanochromones khellin and visnagin react with DNA under irradiation by 365 nm light, forming photoadducts. Recently, the use of khellin as therapeutic agent for skin diseases has been proposed. It is well known that during the formation of photoadducts toxic active oxygen forms are produced. We studied therefore the behaviour of the two furanochromones as producers of 1O-2 and O-2. Our results indicate that visnagin is a strong generator of both superoxide radicals and singlet oxygen, while khellin does not exhibit strong production of OO-2, which is promptly quenched by superoxide dismutase.     

Incorporation of a fatty acid containing a photosensitive group into lipids of cultured cardiac cells from chick embryo

Radioactive 12-(4-azido-2-nitrophenoxy)-stearic acid (NAP-stearate) was synthetized; it behaves as a competitive inhibitor of long-chain fatty acids for the entry into cultured cardiac cells from chick embryo. After uptake, [3H] NAP-stearate was incorporated by an energy-dependent process into neutral and polar lipids. Photoactivation as a function of time leads to a covalent labelling of the cells: up to 31 per cent of the radioactivity was recovered in the 105 000 g cell pellet, mainly in proteins. These experiments show that fatty acids containing photosensitive groups would potentially allow to localize the proteins involved in the binding and/or in the transport of fatty acids.     

Biochemical and molecular characterization of von Willebrand disease type 2N in a pregnant patient who gave birth under analgesia with remifentanil

von Willebrand 's disease (vWD) is the commonest inherited bleeding disorder. Although in literature there are some cases reported of epidural analgesia for labor pain in pregnancies with Von Willebrand's disease, the technique is not free from risk of neurolocal complications. Authors reported a case of spontaneous labor in a pregnant woman with type II vWD, delivered under local analgesia administered through a continuous intravenous infusion of remifentanil integrated by boli. A 34-year-old woman at the 39th week of her second pregnancy was admitted for an active labor of a single fetus in cephalic presentation. The patient had been diagnosed with type II vWD by a hematologist during her first pregnancy. The patient coagulation panel was as follows: a reduction of VIIIth factor concentration (21 percent); a normal value of vWD functional assay; an increase of vWf:Ag (antigen) and a reduction of XIth factor. During labor she was put on remifentanil in PCA (patient controlled analgesia), administered with slow boli followed by continuous infusions at increasing doses. The woman delivered a female fetus weighing 3,550 g, in vertex presentation, in left anterior occipital position, with an A.P.G.A.R. of 8 at the first minute and 9 at the fifth minute. The total duration of labor was 3 hours and 10 minutes. The patient was satisfied with analgesia in labor. The bleeding during and after delivery was regular. In the authors ' opinion, it is important to know that an alternative to epidural analgesia can be used in order to avoid the risk of neurological complications in labor pain for patients with type II Von Willebrand's disease.     

Pollen and seed desiccation tolerance in relation to degree of developmental arrest, dispersal, and survival

In most species, arrest of growth and a decrease in water content occur in seeds and pollen before they are dispersed. However, in a few cases, pollen and seeds may continue to develop (germinate). Examples are cleistogamy and vivipary. In all other cases, seeds and pollen are dispersed with a variable water content (2-70%), and consequently they respond differently to environmental relative humidity that affects dispersal and maintenance of viability in time. Seeds with low moisture content shed by the parent plant after maturation drying can generally desiccate further to moisture contents in the range of 1-5% without damage and have been termed 'orthodox'. Pollen that can withstand dehydration also was recently termed orthodox. Seeds and pollen that do not undergo maturation drying and are shed at relatively high moisture contents (30-70%) are termed 'recalcitrant'. Since recalcitrant seeds and pollen are highly susceptible to desiccation damage, they cannot be stored under conditions suitable for orthodox seeds and pollen. Hence, there are four types of plants with regard to tolerance of pollen and seeds to desiccation. Orthodoxy allows for dispersal over greater distances, longer survival, and greater resistance to low relative humidity. The advantage of recalcitrance is fast germination. Orthodoxy and recalcitrance are often related to environment rather than to systematics. It has been postulated that certain types of genes are involved during presentation and dispersal of pollen and seeds, since molecules (sucrose, polyalcohols, late embryogenic abundant proteins, antioxidants, etc.) that protect different cell compartments during biologically programmed drying have been detected in both.     

Genetic Pleiotropy for Resting Metabolic Rate with Fat-Free Mass and Fat Mass: The Québec Family Study

Shared genetic and familial environmental causes for the associations among resting metabolic rate (RMR), fat-free mass (FFM), and fat mass (FM) were investigated in families participating in phase 2 of the Québec Family Study. A multivariate familial correlation model assessing the pattern of significant cross-trait correlations between family members (e.g., RMR in parents with FFM in offspring) was used to infer the etiology of the associations. For each of FM and FFM with RMR, significant sibling, parent-offspring, and intraindividual cross-trait correlations suggest the associations are familial. Furthermore, the lack of significant spouse cross-trait correlations suggests that the familial aggregation is primarily genetic. Bivariate heritability estimates suggest that as much as 45% to 50% of the shared variance between FFM and RMR may be genetic, and as much as 28% to 34% for FM and RMR. This study supports the notion that the gene(s) affecting each of FFM and FM also influence the RMR. Moreover, the lack of any familial associations between FFM and FM suggests that the effects of each body size component on RMR are independent, i.e., more than one genetic source on the RMR-body size association. The possibility that RMR is an oligogenic trait (i.e., more than one underlying genetic etiology) should be further investigated using more complex multivariate segregation methods until specific genes can be tested.     

The tapetum: Its form,function, and possible phylogeny inEmbryophyta

It appears that the tapetum is universally present in land plants, even though it is sometimes difficult to recognize, because it serves mostly as a tissue for meiocyte/spore nutrition. In addition to this main function, the tapetum has other functions, namely the production of the locular fluid, the production and release of callase, the conveying of P.A.S. positive material towards the loculus, the formation of exine precursors, viscin threads and orbicules (= Ubisch bodies), the production of sporophytic proteins and enzymes, and of pollenkitt/tryphine. Not all these functions are present in all land plants:Embryophyta. Two main tapetal types are usually distinguished in theSpermatophyta: the secretory or parietal type and the amoeboid or periplasmodial type; in lower groups, however, other types may be recognized, with greater or lesser differences. A hypothetical phylogenesis of the tapetum is proposed on the basis of its morphological appearance and of the nutritional relations with meiocytes/spores. The evolutionary trends of the tapeta tend towards a more and more intimate and increasingly greater contact with the spores/pollen grains. Three evolutionary trends can be recognized: 1) an intrusion of the tapetal cells between the spores, 2) a loss of tapetal cell walls, and 3) increasing nutrition through direct contact in narrow anthers.     

Cytogenetic survey of sixty-one patients with preleukemic syndrome including myeloproliferative and myelodysplastic diseases

The authors report on a cytogenetic survey of 61 patients with preleukemic syndrome (PLS). Of these, 41 had a myeloproliferative disease (MPD) and 20 a myelodysplastic syndrome (MDS). Clonal chromosome abnormalities appeared in 24 patients (39.3%) at disease onset. Such changes had a frequency of 26.8% in patients with MPD and 65% in those with MDS. The authors stress the usefulness of ethidium bromide high resolution techniques. They allow obtaining a larger number of metaphases and elongated chromosomes with higher banding resolution and could account for the frequent detection of chromosome changes in most groups of MDS patients in the present series. Moreover, they discuss the possible significance of some chromosome aberrations suggesting that patients with MPD may live longer than those with MDS because of their higher frequency of normal karyotypes.     

Role of endogenous and exogenous prostaglandins on the contractile functioning of isolated sow (Sus scrofa) oviducts

The output prostaglandins (PHs) E₁, E₂ and F₂ α, from ampullary and isthmic portions of sow oviducts isolated during proestrus, estrus and metestrus, was explored. Moreover, $\text{in vitro}$ cumulative dose-response curves for the contractile effect of these three PGs, on identical oviductal segments, were constructed. Isthmic preparations form proestrous and metestrous animals released more PGE₁ and PGF₂ α than PGE₂ “like material”. During estrus, the outputs of PGE₁, PGE₂ and PGF₂ α were similar, whereas, oviducts from proestrous and metestrous sows released less PGE₁ and PGF₂ α than during estrus. Although the output of PGE₂ “like material” from isthmic and ampullary segments did not differ significantly during the three stages of the sex cycle, ampullary metestrous preparations released more PGE₁ and PGF₂ α, than estrous or proestrous ones. The addition of PGE₁, PGE₂ α, consistently stimulatedthe amplitude of contractions of isthmic oviductal segments isolated from proestrous and metestrous sows. Within the concentration-range explored, dose-response curves for PGE₂ and PGE₁ were to the left of those for PGF₂ α in the isthmus obtained before ovulation (proestrus) but not in segments isolated at later times (2–3 days) of the cycle (metestrus). The stimulatory dose-response curves for PGE₁, or PGE₂, in isthmic segments of metestrous preparations incubated with phentolamine (10^?6M) were shifted to the right of controls not exposed to the adrenoreceptor blocker, whereas, the curve for PGF₂ α without phentolamine, was identical to that obtained in its presence. PGE₁ and PGE₂ did not evoke significant contractile effects on oviductal ampullary protions from proestrous sows, wherea, PGF₂ α was clearly stimulatory at concentrations of 10^?9M and higher. In ampullary segments isolated after ovulation (metestrus) the threshold for contractile enhancement following PGF₂ α was greater than during proestrus, whereas, PGE₁ elicited a significant inhibition of contractions. The spontaneous contractile pattern exhibited by isthmic and ampullary oviductal regions, prior to and after ovulation, is discussed in terms of tissue PG generation and output and is compared with results regarding tubal motility following the exposure to exogenous PGs.     

Prostacyclin induces a surprising long-lasting motility in quiescent uterine strips (indomethacin-treated) isolated from ovariectomized rats

Dose-response curves for several prostaglandins (PGI₂; PGD₂; PGF₂ and PGE₂); BaCl₂ or prostaglandin metabolites (15-keto-PGF_2α; 13, 14-diOH-15-keto-PGF_2α; 6-keto-PGF_1α and 6-keto-PGE₁ in quiescent (indomethacin-treated) uterine strips from ovariectomized rats, were constructed. All PGs tested as well as BaCl₂, triggered at different concentrations, evident phasic contractions. Within the range of concentrations tested the portion of the curves for the metabolites of PGF_2α was shifted to the right of that for PGF_2α itself; the curve for 6-keto-PGF_1α was displaced to the right of the curve for PGI₂ and that for 6-keto-PGE₁ to the left.It was also demonstrated that the uterine motility elicited by 10⁻⁵ M PGF_2α and its metabolites was long lasting (more than 3 hours) and so it was the activity evoked by PGI₂; 6-keto-PGF_1α and BaCl₂, but not the contractions following 6-keto-PGE₁, which disappeared much earlier. The contractile tension after PGF_2α; 15-keto-PGF_2α; 13, 14-diOH-15-keto-PGF_2α and PGI₂, increased as time progressed whilst that evoked by 6-keto-PGF_2α or BaCl₂ fluctuated during the same period around more constant levels.The surprising sustained and gradually increasing contractile activity after a single dose of an unstable prostaglandin such as PGI₂, on the isolated rat uterus rendered quiescent by indomethacin, is discussed in terms of an effect associated to its transformation into more stable metabolites (6-keto-PGF_1α, or another not tested) or as a consequence of a factor which might protects prostacyclin from inactivation.