Effects of mother-infant skin-to-skin contact on severe latch-on problems in older infants: a randomized trial

Background

Infants with latch-on problems cause stress for parents and staff, often resulting in early termination of breastfeeding. Healthy newborns experiencing skin-to-skin contact at birth are pre-programmed to find the mother’s breast. This study investigates if skin-to-skin contact between mothers with older infants having severe latching on problems would resolve the problem.

Methods

Mother-infant pairs with severe latch-on problems, that were not resolved during screening procedures at two maternity hospitals in Stockholm 1998–2004, were randomly assigned to skin-to-skin contact (experimental group) or not (control group) during breastfeeding. Breastfeeding counseling was given to both groups according to a standard model. Participants were unaware of their treatment group. Objectives were to compare treatment groups concerning the proportion of infants regularly latching on, the time from intervention to regular latching on and maternal emotions and pain before and during breastfeeding.

Results

On hundred and three mother-infant pairs with severe latch-on problems 1–16 weeks postpartum were randomly assigned and analyzed. There was no significant difference between the groups in the proportion of infants starting regular latching-on (75% experimental group, vs. 86% control group). Experimental group infants, who latched on, had a significantly shorter median time from start of intervention to regular latching on than control infants, 2.0 weeks (Q₁ = 1.0, Q₃ = 3.7) vs. 4.7 weeks (Q₁ = 2.0, Q₃ = 8.0), (p-value = 0.020). However, more infants in the experimental group (94%), with a history of “strong reaction” during “hands-on latch intervention”, latched-on within 3 weeks compared to 33% in the control infants (Fisher Exact test p-value = 0.0001). Mothers in the experimental group (n = 53) had a more positive breastfeeding experience according to the Breastfeeding Emotional Scale during the intervention than mothers in the control group (n = 50) (p-value = 0.022).

Conclusions

Skin-to-skin contact during breastfeeding seems to immediately enhance maternal positive feelings and shorten the time it takes to resolve severe latch-on problems in the infants who started to latch. An underlying mechanism may be that skin-to-skin contact with the mother during breastfeeding may calm infants with earlier strong reaction to “hands on latch intervention” and relieve the stress which may have blocked the infant’s inborn biological program to find the breast and latch on.

Trial registration

Karolinska Clinical Trial Registration number CT20100055     

Sensitive ELISA detection of amyloid-beta protofibrils in biological samples

Amyloid-beta (Abeta) protofibrils are known intermediates of the in vitro Abeta aggregation process and the protofibrillogenic Arctic mutation (APPE693G) provides clinical support for a pathogenic role of Abeta protofibrils in Alzheimer's disease (AD). To verify their in vivo relevance and to establish a quantitative Abeta protofibril immunoassay, Abeta conformation dependent monoclonal antibodies were generated. One of these antibodies, mAb158 (IgG2a), was used in a sandwich ELISA to specifically detect picomolar concentrations of Abeta protofibrils without interference from Abeta monomers or the amyloid precursor protein (APP). The specificity and biological significance of this ELISA was demonstrated using cell cultures and transgenic mouse models expressing human APP containing the Swedish mutation (APPKN670/671ML), or the Swedish and Arctic mutation in combination. The mAb158 sandwich ELISA analysis revealed presence of Abeta protofibrils in both cell and animal models, proving that Abeta protofibrils are formed not only in vitro, but also in vivo. Furthermore, elevated Abeta protofibril levels in the Arctic-Swedish samples emphasize the usefulness of the Arctic mutation as a model of enhanced protofibril formation. This assay provides a novel tool for investigating the role of Abeta protofibrils in AD and has the potential of becoming an important diagnostic assay.     

Detection of Fas ligand in the bovine oviduct

Presence of a Fas-Fas ligand (FasL) system defines the immune-privileged status of certain tissues such as placenta. This study examined the fluids and tissue(s) of the bovine oviduct, where both spermatozoa and early embryos escape elimination by the female immune system, for the presence and the distribution of Fas and FasL, which might provide an explanation for the immune-privileged site of this organ. In the present study, the immunolocalisation of FasL and Fas, as well as the gene expression of FasL, were determined in the uterotubal junction (UTJ), isthmic (I) and ampullar (A) segments of the oviduct during oestrus and the luteal phase of the oestrous cycle. The degree of apoptosis of oviductal epithelium was examined by the TUNEL method. Oviductal fluid (ODF), collected chronically via indwelling catheters from the I or A segments during both non-luteal and luteal phases of the cycle, was analysed for the presence of FasL. The Fas immunostaining was scattered along the epithelium of all regions of the oviduct and cycle stages investigated, whereas FasL immunolabelling was more conspicuous in oestrous samples. This staining disappeared during the luteal phase, which was particularly evident in the sperm reservoir (UTJ and I). There were fewer TUNEL-positive cells than Fas- or FasL-positive cells in the oviductal epithelium, suggesting that tubal Fas and FasL are not directly involved in epithelial apoptosis. Western blot analyses detected FasL in ODF collected from both I and A, most conspicuously as a 24-27kDa band but also at a 40-45kDa band level. FasL mRNA was expressed in the epithelial cells from the sperm reservoir and A during both non-luteal and luteal phases. However, the level of expression differed significantly between segments during the luteal phase. The results provide novel evidence that the Fas-FasL system is present in the bovine oviduct and could be involved in mediating survival of spermatozoa and early embryos.     

Nitrogen fixation and biomass production in symbioses between Alnus incana and Frankia strains with different hydrogen metabolism

Three different strains of Frankia , the pure cultures AvcI1 and CpI1 and a local strain (crushed nodule inoculum), were compared in symbiosis with one clone of Alnus incana (L.) Moench. Hydrogen metabolism, nitrogenase (EC 1.7.99.2) activity and relative efficiency of nitrogenase were studied as well as growth and nitrogen content of the plants. The local Frankia strain showed no measurable hydrogen uptake but high H₂-evolution. No H₂-evolution was detected in Frankia AvcI1 because of its hydrogenase activity. CpI1 also had hydrogenase, although only a very small H₂-evolution was detected at the end of the growth period. Hydrogenase activity was detected both in pure cultures and nodule homogenates of CpI1 and AvcI1. Growth, biomass production and nitrogen content were highest in alders inoculated with Frankia AvcI1 while the lowest values were found for alders living in symbiosis with the local Frankia strain. The presence of hydrogenase in Frankia seemed to be benefical for growth and biomass production in the alders. However, the strains also differed with respect to spore formation. The local strain, but not AvcI1 and CpI1, formed spores in the root nodules.     

Occurrence and potential pathogenesis of Vibrio cholerae, Vibrio parahaemolyticus and Vibrio vulnificus on the South Coast of Sweden

During the summer of 2006, several wound infections - of which three were fatal - caused by Vibrio cholerae were reported from patients who had been exposed to water from the Baltic Sea. Before these reports, we initiated a sampling project investigating the occurrence of potential human pathogenic V. cholerae, Vibrio vulnificus and Vibrio parahaemolyticus in The Sound between Sweden and Denmark. The Blue mussel (Mytilus edulis) was used as an indicator to follow the occurrence of vibrios over time. Molecular analyses showed high frequencies of the most potent human pathogenic Vibrio spp.; 53% of mussel samples were positive for V. cholerae (although none were positive for the cholera toxin gene), 63% for V. vulnificus and 79% for V. parahaemolyticus (of which 47% were tdh(+) and/or trh(+)). Viable vibrios were also isolated from the mussel meat and screened for virulence by PCR. The mortality of eukaryotic cells when exposed to bacteria was tested in vivo, with results showing that the Vibrio strains, independent of species and origin, were harmful to the cells. Despite severe infections and several deaths, no report on potential human pathogenic vibrios in this area had been published before this study.     

Selective quantification of free 3-nitrotyrosine in exhaled breath condensate in asthma using gas chromatography/tandem mass spectrometry.

Reactive nitrogen species can cause oxidative modifications of certain amino acid residues in proteins, notably the modification of tyrosine to 3-nitrotyrosine (3-NT), which is a potentially useful marker of oxidative stress. Since lung diseases are associated with airway inflammation and oxidative stress, quantification of 3-NT in exhaled breath condensate (EBC) may provide a non-invasive means for monitoring ongoing inflammatory processes. 3-NT-like immunoreactivity has previously been detected in EBC, but no definitive evidence for the presence of 3-NT in EBC is available. Here, a method based on gas chromatography/negative ion chemical ionization/tandem mass spectrometry was established for the quantification of free 3-NT in EBC. The detection limit was 0.56 pM (corresponding to 3.0 amol microl(-1) sample injected) and the method was found to give linear results (r2 > 0.999) in the concentration range of 0-5.0 nM. The coefficient of variation (CV) for within-day and between-day precision were 11 and 12%, respectively. No artifactual nitration was observed during sample processing. The method was applied to study subjects with asthma (n = 8), and healthy subjects (n = 10), but only a slight non-significant increase in 3-NT levels was found in the former group (median [interquartile ranges]; 99 [50-547] amol s(-1) vs. 75 [35-147] amol s(-1)). No correlation with exhaled nitric oxide (NO), pulmonary function or EBC levels of total protein was observed. The 3-NT levels were much lower compared to previously reported levels, based on immunochemical measurements. The method does not allow the simultaneous quantification of tyrosine in samples.     

Loss and recovery of nitrogenase in Abuts incana nodules exposed to low oxygen and low temperature

The possibility that respiration limits oxygen access to nitrogenase was tested by artificially upsetting the balance between oxygen consumption (respiration) and oxygen influx (diffusion). Argon treatment of the nodulated root system on intact plants stopped in vivo nitrogenase activity almost completely. Upon return to air, nitrogenase activity was very low and recovered gradually to full activity after about 5 h. In vitro measurements on nodule homogenates indicated that active nitrogenase was lost upon the shift from low (argon) to normal (air) oxygen. Maintenance of nodulated root systems at low temperature (2°C) inhibited both respiration and in vivo nitrogenase activity. Upon return to normal temperature (22°C), oxygen uptake recovered very rapidly, but nitrogenase activity recovered only gradually to full activity after about 5 to 6 h. Again, loss of active nitrogenase could, at least partly, explain the reduced in vivo nitrogenase activity. The effects from a temporarily impaired balance between oxygen consumption and oxygen influx thus point to the importance of respiration for limiting oxygen access to nitrogenase.     

Nitrogenase activity in root nodule homogenates ofAlnus incana

Summary Root nodule homogenates of actinorhizal plants may representFrankia in a symbiotic stage but released from environmental influence of the host plant. Anaerobic homogenization with a blender in buffer supplied with sucrose, polyvinylpyrrolidone and reducing substances gave three times higher yields of nitrogenase activity (C₂H₂-reduction) than crushing the nodules in liquid nitrogen. The activity in the homogenates was very reproducible and was, on average, nearly twice as high as the activity in excised nodules and c. 10% of the activity in intact plants. The difference in activity between excised nodules and intact plants was, roughly by halves, due to removal of the root system from the pot and to excision of the nodules. The nitrogenase activity in the homogenates was slightly higher when nodule excision was done in Ar or under water as well as after treatment of the homogenate with toluene or Triton X-100 or osmotic shock. These gains in activity were considered too small to outweigh the increased complications of preparing homogenates for routine use. Due to the reproducible recovery of nitrogenase in the homogenates the technique seems useful for physiological studies on nitrogen fixation inAlnus incana.     

Docosahexaenoic acid stabilizes soluble amyloid-beta protofibrils and sustains amyloid-beta-induced neurotoxicity in vitro

Enrichment of diet and culture media with the polyunsaturated fatty acid docosahexaenoic acid has been found to reduce the amyloid burden in mice and lower amyloid-beta (Abeta) levels in both mice and cultured cells. However, the direct interaction of polyunsaturated fatty acids, such as docosahexaenoic acid, with Abeta, and their effect on Abeta aggregation has not been explored in detail. Therefore, we have investigated the effect of docosahexaenoic acid, arachidonic acid and the saturated fatty acid arachidic acid on monomer oligomerization into protofibrils and protofibril fibrillization into fibrils in vitro, using size exclusion chromatography. The polyunsaturated fatty acids docosahexaenoic acid and arachidonic acid at micellar concentrations stabilized soluble Abeta42 wild-type protofibrils, thereby hindering their conversion to insoluble fibrils. As a consequence, docosahexaenoic acid sustained amyloid-beta-induced toxicity in PC12 cells over time, whereas Abeta without docosahexaenoic acid stabilization resulted in reduced toxicity, as Abeta formed fibrils. Arachidic acid had no effect on Abeta aggregation, and neither of the fatty acids had any protofibril-stabilizing effect on Abeta42 harboring the Arctic mutation (AbetaE22G). Consequently, AbetaArctic-induced toxicity could not be sustained using docosahexaenoic acid. These results provide new insights into the toxicity of different Abeta aggregates and how endogenous lipids can affect Abeta aggregation.     

Fractionation of wheat and barley straw to access high-molecular-mass hemicelluloses prior to ethanol production

The cost efficiency of the biorefining process can be improved by extracting high-molecular-mass hemicelluloses from lignocellulosic biomass prior to ethanol production. These hemicelluloses can be used in several high-value-added applications and are likely to be important raw materials in the future. In this study, steam pretreatment in an alkaline environment was used to pretreat the lignocellulosic biomass for ethanol production and, at the same time, extract arabinoxylan with a high-molecular-mass. It was shown that 30% of the arabinoxylan in barley straw could be extracted with high-molecular-mass, without dissolving the cellulose. The cellulose in the solid fraction could then be hydrolysed with cellulase enzymes giving a cellulose conversion of about 80–90% after 72 h. For wheat straw, more than 40% of the arabinoxylan could be extracted with high-molecular-mass and the cellulose conversion of the solid residue after 72 h was about 70–85%. The high cellulose conversion of the pretreated wheat and barley straw shows that they can be used for ethanol production without further treatment. It is therefore concluded that it is possible to extract high-molecular-mass arabinoxylan simultaneously with the pretreatment of biomass for ethanol production in a single steam pretreatment step.