Efficacy of a new tonic containing urea, lactate, polidocanol, and glycyrrhiza inflata root extract in the treatment of a dry, itchy, and subclinically inflamed scalp

BACKGROUND/AIMS

Dry, itchy and inflamed scalp conditions are common and often associated with diseases such as atopic dermatitis or psoriasis. To improve these symptoms, we investigated the efficacy of a new tonic containing the active ingredients urea, lactate, polidocanol, and Glycyrrhiza inflata root extract, containing licochalcone A.

STUDY DESIGN/METHODS

30 subjects with dry and itchy scalp conditions underwent a randomized half-head study for 4 weeks, applying the leave-on tonic three times a week on one side of the scalp. Tonic effects on skin hydration, itching, lipids, microinflammation, and substantivity of tonic compounds were determined using corneometry, middle-infrared spectroscopy, direct analysis in real-time mass spectrometry, and enzyme-linked immunosorbent assay. Volunteers performed a self-assessment; changes in scalp condition were documented by in vivo microscopy.

RESULTS

After tonic treatment, scalp moisture was significantly increased, whereas scalp itching and tautness were significantly reduced. Results also demonstrated a high substantivity of urea and lactate on the scalp, an increase in triglyceride, and a decrease in free fatty acid levels. The amount of total lipids was unchanged. Analyses of scalp wash-ups verified a significant reduction in important pro-inflammatory markers.

CONCLUSION

Due to the actives urea, lactate, polidocanol, and the anti-inflammatory licochalcone A, the new scalp tonic exhibited excellent performance in alleviating scalp dryness, itching, microinflammation, and in normalizing disturbances of scalp lipids.

Chorioallantoic and Yolk Sac Placentation in the Dassie Rat Petromus typicus and its Significance for the Evolution of Hystricognath Rodents

Placental characters are most important in understanding the evolutionary history of hystricognath rodents of which some act as animal models for human pregnancy. The data available deal mostly with species native to South America, but the current paper presents novel findings on chorioallantoic and yolk sac placentation in an Old World hystricognath and discusses its significance for the evolution of the group. Several hystricognath stem species characters are verified for Petromus, such as the unique trophoblast growth pattern within the chorioallantoic placenta. Subsequently, a novel set of characters belonging to the visceral yolk sac is added to the stem species pattern of the group. The nourishment of the embryo is facilitated by an inverted visceral yolk sac placenta from early pregnancy onward, later complemented by the chorioallantoic placenta. About mid term, the visceral yolk sac becomes partly folded and attached to the parietal yolk sac cover of the chorioallantoic placenta, suggesting a functional shift to the transfer of substances between the two placental types. Thus, the chorioallantoic and yolk sac placenta collaborate in nurturing the embryo. This apparently represents an evolutionary transformation along the stem lineage of hystricognaths.

Caviomorph placentation as a model for trophoblast invasion

The guinea pig and its relatives are promising candidates as animal models for studying trophoblast invasion. The origin, migration routes and kinetics of invasive trophoblast cells were examined in two caviomorph species. Histology and immunohistochemistry were done on placentas from 38 guinea pigs of days 20-47 and 13 degus of days 25-51 of gestation. BrdU was used as an in vivo marker for proliferation and for tracing of migration routes in the placenta; it was injected 24h to 15 days before collecting the material. In both species extravillous-like trophoblast cells are derived from proliferating stem cell aggregations in the subplacenta, which are comparable to the cell columns in humans. Migration routes and kinetics under in vivo conditions revealed a mean invasive depth of 300-350 microm/day and a mean life span of the extravillous-like trophoblast of 30 days. The patterns of trophoblast invasion in caviomorphs are analogous to the situation in humans, suggesting that these rodents are appropriate animal models for the study of the dynamics of trophoblast invasion.

Evolution of the Placenta in Eutherian Mammals

We review recent advances in our understanding of placental evolution with particular focus on the interhaemal barrier. It seems likely that the non-invasive, epitheliochorial placentation of living eutherians is a derived state. However, there is disagreement on whether the last common ancestor of eutherian mammals had an endotheliochorial placenta or a haemochorial one. Research has been stimulated by improved understanding of the relations between the orders of mammals provided by molecular phylogenetics. In part, the uncertainties arise from doubt about how to root the mammalian tree. Resolution of this issue will require improved taxon sampling in molecular analyses. At the same time, we need to foster research in comparative placentation on relevant taxa, particularly at the ultrastructural level. Only then can we ensure that information available about the placenta is adequate to capitalise on future advances in molecular phylogenetics. Examples are given of recent findings that could benefit cladistic analysis of placental evolution.

Evolutionary Differentiation of Cetartiodactyl Placentae in the Light of the Viviparity-Driven Conflict Hypothesis

We analysed the evolution of placental traits in the novel mammalian clade Cetartiodactyla (Cetaceans and Artiodactyls) by a parsimony-based computer program (MacClade). A diffuse epitheliochorial placenta was identified as the stem species pattern of this clade. Trophoblast giant cells (TGCs) independently evolved in Camelids and Ruminants. The polycotyledonary placenta is an apomorphic character for Pecora (higher ruminants) and the oligocotyledonary placenta developed as a further step on the stem lineage of cervidae and moschidae. We interpret these findings by application of the "viviparity-driven conflict hypothesis", which states that divergent interests of mother and offspring lead to a rapid antagonistic coevolution, which might cause placental diversity. According to this hypothesis the evolution of camelid and ruminant TGCs can be interpreted as means to increase fetal endocrine influence on the maternal metabolism. The development of the cotyledonary placenta could be related to a diminished availability of glucose, which is associated with the evolution of forestomach fermentation in Pecora. An arms race, in which the mother tried to restrict and the fetus tried to increase transplacental glucose flow, might have promoted the evolution of the cotyledonary placenta, which has a high feto-maternal exchange area, but a low conductivity for glucose.

The Guinea pig placenta: model of placental growth dynamics

Placental growth dynamics are an important, but poorly understood aspect of placentation for which suitable animal models are lacking. Although the guinea pig is recognised as a valuable model for human pregnancy, its suitability for this purpose is not apparent, since the developmental and evolutionary processes that led to its lobulated placenta are not fully understood. Therefore, a study on immunohistochemistry has been undertaken, including the antibody mib-1 against protein Ki-67 as a proliferation marker. It was found that cellular trophoblast derived from the placental margin is the major centre of proliferation, supported by a moderate number of proliferating cells inside the labyrinth. In contrast to the ancestral condition of caviomorph rodents, the evolution of significant placental lobulation requires the latter source of proliferation. The distribution pattern of proliferating trophoblast cells revealed for the guinea pig strongly resembles the distribution in the human placenta in that (a) evenly distributed, moderate numbers of cells occur within the exchange area and (b) focal accumulations of proliferating trophoblast cells are present along the fetal mesenchymal border and appear to serve as a growth zone for appositional growth of new exchange tissues. Thus, the guinea pig appears to be an appropriate animal model for placental growth processes in human pregnancies.

Mesotocin gene expression in the diencephalon of domestic fowl: cloning and sequencing of the MT cDNA and distribution of MT gene expressing neurons in the chicken hypothalamus

This study focuses on the structure and expression of the mesotocin (MT) gene in the chicken hypothalamus. Using an anchored and nested RT-PCR strategy, combined with circular RACE-PCR, the full length sequence of the chicken MT cDNA was obtained. The cDNA and derived amino acid sequences conformed to the structure of the oxytocin-like gene family. However, unlike most mammalian species, there does not appear to be frequent gene conversion between the MT and AVT cDNA sequences. A single specific hybridization signal of 1.2 kb was detected by Southern analysis of chicken genomic DNA, indicating only a single gene copy in the chicken genome. Northern analysis of hypothalamic RNA revealed a single band at approximately 0.6 kb. Using the same probe for in situ hybridization histochemistry, MT-mRNA was demonstrated to be predominantly localized in the parvocellular, magnocellular and periventricular subgroups of the paraventricular nucleus and, when compared to the distribution of neurons containing arginine-vasotocin (AVT)-mRNA in the same region, with far fewer neurons expressing the MT gene in the lateral subgroups. Only few and scattered neurons expressing the MT gene were found in the ventral and external subgroups of the supraoptic nucleus in which many neurons contain AVT transcripts, as demonstrated in consecutive sections. In all nuclei investigated, the intensity of AVT and MT hybridization signals per cell was approximately equal. No specific labelling for MT-mRNA was found in the bed nucleus of the stria terminalis, nor the nucleus accumbens. Using immunocytochemical detection of AVT and in situ hybridization for neurons expressing MT-mRNA, some neurons were found to contain both AVT and MT gene products in the paraventricular nucleus but not in the supraoptic nucleus.